THEREUNDER

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This patent application claims the benefit of, and priority to, U.S.

Provisional Patent Application Serial No. 62/770,531 , filed November 21 , 2018, the disclosure of which is expressly incorporated herein by reference in its entirety.

FIELD:

[0002] The present disclosure relates generally to height-adjustable work tables, and more specifically to systems and methods for preventing contact between the work top of a height-adjustable work table and an object disposed thereunder.

BACKGROUND

[0003] Conventional motor-driven height-adjustable work tables typically include one or more electrical drive motors selectively operable to increase or decrease the height(s) of one or more height-adjustable column members supporting a work top thereon. Any object(s) positioned under the work top may accordingly be susceptible to unintended contact with the work top as it is being lowered by the one or more drive motors.

SUMMARY

[0004] This disclosure may comprise one or more of the features recited in the attached claims, and/or one or more of the following features and combinations thereof. In one aspect, a system is provided for preventing contact between a work top of a height-adjustable work table and an object disposed thereunder, wherein the work table includes at least one electric drive motor for moving the work top upwardly and downwardly. In this aspect, the system may comprise at least one sensor assembly configured to be mounted to the work table and to produce at least one object detection signal in response to an object being within a sensing range thereof, at least one computing device, and at least one memory unit having instructions stored therein executable by the at least one computing device to cause the at least one computing device to control the at least one electric drive motor to stop or disable downward movement of the work top in response to determining from the at least one object detection signal that the object is within a predefined distance of an underside of the work top.

[0005] In another aspect, a system is provided for preventing contact between a work top of a height-adjustable work table and an object disposed thereunder, wherein the work table includes at least one electric drive motor for moving the work top upwardly and downwardly. In this aspect, the system may comprise at least one radiation transmitter configured to be mounted to the work table and responsive to activation thereof to emit radiation signals along an underside of the work top or downwardly away from the underside of the work top, at least one radiation receiver configured to be mounted to the work table and configured to produce radiation detection signals, the radiation detection signals including at least one object detection signal in response to an object being within a detection range thereof, at least one computing device, and at least one memory unit having instructions stored therein executable by the at least one computing device to cause the at least one computing device to activate the at least one radiation transmitter, to process the resulting radiation detection signals and to control the at least one drive motor to stop or disable downward movement of the work top in response to determining from the at least one object detection signal that the object is within a predefined distance of the underside of the work top.

[0006] In yet another aspect, a method is provided for preventing contact between a work top of a height-adjustable work table and an object disposed thereunder, wherein the work table includes at least one electric drive motor for moving the work top upwardly and downwardly. In this aspect, the method may comprise receiving, with at least one computing device, at least one object detection signal from at least one sensor assembly mounted to the work table and producing the at least one detection signal in response to an object being within sensing range thereof, determining, by the at least one computing device from the at least one detection signal, whether the object is within a predefined distance of an underside of the work top, and controlling, by the at least one computing device, the at least one drive motor to stop or disable downward movement of the work top in response to determining that the object is within the predefined distance of the underside of the work top. [0007] In still another aspect, at least one non-transitory computer readable storage medium has stored thereon instructions executable by at least one computing device for executing a process for preventing contact between a work top of a height-adjustable work table and an object disposed thereunder, the work table including at least one electric drive motor for moving the work top upwardly and downwardly. In this aspect, the at least one computing device may execute the process according to the instructions by receiving at least one object detection signal from at least one sensor assembly mounted to the work table and producing the at least one detection signal in response to an object being within sensing range thereof, determining from the at least one detection signal whether the object is within a predefined distance of an underside of the work top, and controlling the at least one drive motor to stop or disable downward movement of the work top in response to determining that the object is within the predefined distance of the underside of the work top.

[0008] In a further aspect, a system is provided for preventing contact between a work top of a height-adjustable work table and an object disposed thereunder, wherein the work table includes at least one electric drive motor for moving the work top upwardly and downwardly. In this aspect, the system may comprise at least one sensor assembly configured to be mounted to the work table and to produce an object detection signal in response to detection of an object within a predefined distance of an underside of the work top, at least one computing device, and at least one memory unit having instructions stored therein executable by the at least one computing device to cause the at least one computing device to control the at least one electric drive motor to stop or disable downward movement of the work top in response to the object detection signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] This disclosure is illustrated by way of example and not by way of limitation in the accompanying Figures. Where considered appropriate, reference labels have been repeated among the Figures to indicate corresponding or analogous elements.

[0010] FIG. 1A is a simplified perspective view of an embodiment of a height- adjustable work table including an embodiment of a system for preventing contact between the work top and an object disposed under the work top. [0011] FIG. 1 B is a simplified plan view of an underside of the work top of the height-adjustable work table of FIG. 1 A.

[0012] FIG. 1 C is a front elevational view of the height-adjustable work table of FIGS. 1 A and 1 B.

[0013] FIG. 1 D is a cross-sectional view of the height-adjustable work table of FIGS. 1 A-1 C as viewed along section lines 1 D-1 D of FIG. 1 C.

[0014] FIG. 2A is a perspective view of an embodiment of an object sensor assembly forming part of the apparatus and system of FIGS. 1 A-1 D.

[0015] FIG. 2B is a front elevational view of the object sensor assembly illustrated in FIG. 2A.

[0016] FIG. 2C is a side elevational view of the object sensor assembly of FIGS. 2A and 2B.

[0017] FIG. 3A is a perspective view of the object sensor sub-assembly of the sensor assembly illustrated in FIGS. 2A-2C.

[0018] FIG. 3B is a side elevational view of the object sensor sub-assembly of FIG. 3A.

[0019] FIG. 4A is a front elevational view of the frame or bracket of the object sensor assembly illustrated in FIGS. 2A-2C.

[0020] FIG. 4B is a rear perspective view of the frame or bracket of FIG. 4A.

[0021] FIG. 5A is a perspective view of a top housing component of the housing sub-assembly of the sensor assembly illustrated in FIGS. 2A-2C.

[0022] FIG. 5B is a perspective view of a bottom housing component of the housing sub-assembly of the sensor assembly illustrated in FIGS. 2A-2C.

[0023] FIG. 6 is a simplified diagram illustrating object sensing operation of the object sensor sub-assembly illustrated in FIGS. 3A-3B.

[0024] FIG. 7A is a simplified schematic diagram of an embodiment of the system for preventing contact between the work top and an object disposed under the work top of the height-adjustable work table of FIGS. 1 A-1 D.

[0025] FIG. 7B is a simplified schematic diagram of another embodiment of the system for preventing contact between the work top and an object disposed under the work top of the height-adjustable work table of FIGS. 1 A-1 D.

[0026] FIG. 8 is a simplified flowchart illustrating an embodiment of a process executable by a computing device for preventing contact between the work top and an object disposed thereunder based on signals provided by the one or more object detection sensors.

[0027] FIG. 9 is a side-elevational view of the height-adjustable work table of FIGS. 1 A-1 D demonstrating one example sub-process of the process illustrated in FIG. 8.

[0028] FIGS. 10A and 10B are side-elevational views of the height-adjustable work table of FIGS. 1 A-1 D demonstrating another example sub-process of the process illustrated in FIG. 8.

[0029] FIG. 1 1 is a simplified perspective view of another embodiment of a height-adjustable work table to which is mounted another embodiment of a system for preventing contact between the work top and an object disposed under the work top thereof.

[0030] FIG. 12 is a simplified perspective view of an underside of a work top of a height-adjustable work table illustrating another embodiment of an object sensor assembly mounted thereto.

[0031] FIG. 13 is a simplified perspective view of an underside of a work top of a height-adjustable work table illustrating yet another embodiment of an object sensor assembly mounted thereto

DETAILED DESCRIPTION OF THE DRAWING

[0032] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawing and will herein be described in detail.

It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims.

[0033] References in the specification to "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases may or may not necessarily refer to the same embodiment. Further, when a particular feature, structure or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure or characteristic in connection with other

embodiments whether or not explicitly described. Further still, it is contemplated that any single feature, structure or characteristic disclosed herein may be combined with any one or more other disclosed feature, structure or characteristic, whether or not explicitly described, and that no limitations on the types and/or number of such combinations should therefore be inferred.

[0034] Referring now to FIGS. 1 A-1 D, a height-adjustable work table 12 is shown including an embodiment of a system 10 for preventing contact between the work top 14 of the table 12 and an object disposed under the work top 14. The height-adjustable work table 12 illustratively has a support frame 16 including two spaced-apart, vertically-disposed supports 18A, 18B coupled together at one end via an axial support member 20. The underside 14B of the work top 14 of the work table 12 is positioned on and supported by the supports 18A, 18B and 20 such that a work surface 14A opposite the underside 14B provides a height-adjustable work surface.

In the embodiment illustrated in FIGS. 1A-1 D, each support 18A, 18B includes a height-adjustable column member 22A, 2B coupled at a lower end to a respective lateral or transverse base member 24A, 24B supported on and by a support surface 26, e.g., a floor. Upper ends of the height-adjustable column members 22A, 22B are coupled to respective lateral or transverse table support members 28A, 28B. In the illustrated embodiment, opposite ends of the axial support member 20 couple to the transverse table support members 28A, 28B adjacent to aligned ends thereof that are spaced apart from a rear edge 14D of the work top 14, and the opposite ends of the transverse table support members 28A, 28B extend toward a front edge 14C of the work top 14. The work top 14 is thus supported on the lateral support members 28A, 28B and the axial support 20. In some embodiments, the lateral support members 28A, 28B and the axial support 20 are secured to the underside 14B of the work top 14, and in other embodiments only the lateral support members 28A, 28B are secured to the underside 14B of the work top 14. The work top 14 may defined any thickness between the top surface 14A and the bottom surface or underside 14B thereof, and may define any shape about its perimeter.

[0035] In the illustrated embodiment, the axial support 20 is provided in the form of side-by-side elongated axial support members 20A, 20B illustratively coupled, e.g., affixed, attached or otherwise secured, to one another. Conventional motor boxes 30A, 30B are shown positioned at opposite ends of the support 20 with the motor box 30A coupled, e.g., affixed, attached or otherwise secured, to one end of the axial support member 20B and the motor box 30B coupled, i.e., affixed, attached or otherwise secured, to one end of the axial support member 20A. The motor boxes 30A, 30B are operatively coupled to the upper ends of the height- adjustable support columns 22A, 22B respectively. In the illustrated embodiment, height adjustment of the height-adjustable support columns 22A, 22B is motor driven, and each support 22A, 22B is operatively coupled to a respective drive motor 152A, 152B (see FIGS. 7A and 7B) carried within a respective one of the motor boxes 30A, 30B.

[0036] A main control module 32 is illustratively coupled to the underside 14B of the work top 14 adjacent to the axial support member 20A, although in alternate embodiments the control module 32 may be positioned adjacent to the axial support member 20B or coupled to either support member 20A, 20B. The control module 32 illustratively houses a computing device operatively coupled to the drive motors 152A, 152B and to a user interface module 35 (see FIGS. 7A and 7B), and is configured, i.e., programmed, to control operation of the drive motors 152A, 152B in a conventional manner, based on user interaction with the user interface module 35, to drive the work top 14 upwardly and downwardly.

[0037] At least one object detection sensor assembly is illustratively mounted to the support frame 16 and/or to the underside 14B of the work top 14. In the embodiment illustrated in FIGS. 1 A-1 D for example, four such object detection sensor assemblies 36A-36D are mounted to the support frame 16; two spaced-apart object detection sensor assemblies 36A, 36B mounted to the transverse table support member 28A and separated by the support 22A, and two spaced-apart object detection sensor assemblies 36C, 36D mounted to the transverse table support member 28B and separated by the support 22B. It will be understood, however, that the embodiment illustrated in FIGS. 1 A-1 D represents only one example embodiment, and that other embodiments are contemplated which include more or fewer object detection sensors mounted to the support frame 16 and/or to the underside 14B of the work top 14.

[0038] In some embodiments, an impact avoidance control module 38 may also be coupled to the underside 14B of the work top 14 and/or to either of the axial support members 20A, 20B as illustrated by example in FIGS. 1 A and 1 B, and in such embodiments the impact avoidance control module 38 is operatively coupled to the main control module 32 and to each of the object detection sensor assemblies.

In such embodiments, as will be described in greater detail below with respect to FIGS. 7 A and 8-1 OB, a computing device housed by the module 38 is configured, e.g., programmed, to monitor signals produced by the one or more object detection sensors, to process such signals and to communicate a suitable message to the main control module 32 when impact with an object disposed between the underside 14B of the work top 14 and the support surface 26, e.g., floor, is imminent so that the main control module 32 may then control the drive motors 152A, 152B to stop downward movement of the work top 14, or to disable the drive motors 152A, 152B to disable downward movement of the work top 14 if the work top 14 is not yet moving, so as to avoid contact between the underside 14B of the work top 14 and the object. In alternate embodiments, as will be described in greater detail below with respect to FIG. 7B, the impact avoidance control module 38 may be omitted, the main control module 32 may be operatively coupled to each of the object detection sensor assemblies, and the computing device housed within the control module 32 may execute the impact avoidance process just described. In still other

embodiments, one or more of the sensor assemblies may include a computing device programmed to execute at least a portion of the impact avoidance process just described. In any case, the object detection sensor assemblies are, in some embodiments, each connected by one or more conventional signal paths, e.g., wires or cables, to the respective control module 32, 38, although in other embodiments the respective control module 32, 38 and one or more of the object detection sensor assemblies may be configured wirelessly communicate with one another.

[0039] Referring now to FIGS. 2A-2C, an embodiment of one of the object detection sensor assemblies 36A is shown. In some embodiments, each of the object detection sensor assemblies 36B-36D are identical to the object detection sensor assembly 36A, although in other embodiments one or more of the object detection sensor assemblies 36B-36D may be different from the object detection sensor assembly 36A. In any case, the embodiment of the object detection sensor assembly 36A depicted in FIGS. 2A-2C illustratively includes a frame or bracket 50, an object detection sensor sub-assembly 52 and a housing 54. Details of the object detection sensor sub-assembly 52 are illustrated in FIGS. 3A-3B, details of the frame or bracket 50 are illustrated in FIGS. 4A-4B and details of the housing 54 are illustrated in FIGS. 5A and 5B respectively. [0040] Referring specifically to FIGS. 3A and 3B, the object detection sensor sub-assembly 52 illustratively includes two object sensor sub-assemblies 60, 70 coupled together. The object sensor sub-assembly 60 illustratively includes a radiation transmitter 62 and a radiation receiver 64 each mounted to a circuit board 66 and operatively connected to conventional circuitry 68 also mounted to the circuit board 66 and operable to activate the transmitter 62 to transmit radiation and to activate the receiver 64 to receive radiation signals. In one embodiment, the object sensor sub-assembly 60 is an ultrasonic range sensor in which the transmitter 62 is operable to transmit ultrasonic radiation signals and the receiver 64 is operable to receive reflected ultrasonic radiation signals, i.e., ultrasonic radiation signals transmitted by the transmitter 62 and reflected by an object back to the receiver 64.

In the illustrated embodiment, the object sensor sub-assembly is a model HC-SR04 ultrasonic range sensor commercially available via Amazon.com® on-line retailer. The HC-SR04 has a ranging distance of 2 centimeters (cm) - 400 cm, and a resolution of 0.3 cm. In other embodiments, the object sensor sub-assembly 60 may be implemented using other ultrasonic range sensors or any conventional range sensor operating in any frequency range of the electromagnetic spectrum. In some embodiments, example applications of which are described below, the circuitry 68 may include at least one conventional computing device. In some such

embodiments, the circuitry 68 may further include at least one conventional memory unit having stored therein instructions executable by the computing device(s) to perform object detection as described below. In some such embodiments, the circuitry 68 may further include at least one conventional communication circuit operatively coupled to the computing device(s) to enable or facilitate communication between the computing device(s) and the computing device of the main control module 32 and/or the computing device of the impact avoidance control module 38 in embodiments which include the module 38.

[0041] The object sensor sub-assembly 70 illustratively includes a radiation transmitter 72 and a radiation receiver 74 each mounted to a circuit board 76. In one embodiment, the object sensor sub-assembly 70 is a conventional infrared sensor in which the transmitter 72 is operable to transmit infrared radiation signals and the receiver 74 is a conventional infrared sensor operable to receive reflected infrared radiation signals, i.e., infrared radiation signals transmitted by the transmitter 72 and reflected by an object back to the receiver 74. In one example embodiment, the infrared transmitter 72 is an LTE-5208A infrared LED emitter and the infrared receiver 74 is an LTR-3208E infrared LED sensor, both commercially available via Lite-On® on-line retailer. The LTE-5208A/LTR-3208 pair has a ranging distance of approximately 2 centimeters (cm) - 2 meters (m). In other embodiments, the object sensor sub-assembly 70 may be implemented using any conventional

sensor/receiver pair operating in any frequency range of the electromagnetic spectrum.

[0042] In the illustrated embodiment, the circuit boards 66, 76 of the respective object sensor sub-assemblies 60, 70 are mechanically and electrically coupled or mounted to one another via a number of electrically conductive pins 78 such that the direction of radiation transmission and reception of the object sensor sub-assembly 60 is approximately normal to that of the object sensor sub-assembly 70. In other embodiments, the direction of radiation transmission and reception of the object sensor sub-assemblies 60, 70 may be non-normal relative to one another. In any case, in embodiments in which the object detection sensor assembly 36A is electrically coupled to the control module 32 or 38 via a physical, e.g., wired, connection, electrical connection between the control module 32 or 38 and the object sensor sub-assemblies 60, 70 is made via the electrically conductive pins 78.

[0043] Referring now specifically to FIGS. 5A and 5B, an embodiment of the housing 54 is shown which illustratively includes a pair of side walls 98A, 98B which defines a top wall 100 and a front wall 1 10 therebetween, wherein the front wall 1 10 also extends downwardly from one end of the top wall 100. A number, e.g., four, of bosses 102A-102D extend downwardly from an interior surface 1 12B of the top wall 100, and each of the bosses 102A-102D define a bore, e.g., threaded bore, therein for receiving a conventional fixation member, e.g., a screw. The bosses 102A-120D are illustratively arranged to align with openings in the circuit board 76 of the object sensor sub-assembly 70, and fixation members are passed through the circuit board 70 and into the bosses 102A-102D to secure the object detection sensor sub- assembly 52 to the housing 54. A pair of support channels 103 (only one shown in FIG. 5B) are defined adjacent to the bosses 102B and 102C and are configured to receive the top edge of the circuit board 66 therein.

[0044] A number, e.g., four, of elongated clips 104A-104D also extend downwardly from the top wall 100; two of the clips 104A, 104D extending

downwardly from the top wall 100 adjacent to the rear edge thereof, and two of the clips 104B, 104C extending downwardly from the top wall 100 adjacent to the front edge thereof with the front wall 1 10 positioned between the clips 104B, 104C as best illustrated in FIG. 5A. Each of the clips 104A-104D illustratively defines a detent 1 14 at a free end thereof for engagement with a respective opening in the frame or bracket 50 to secure the housing 54 to the frame or bracket 50. The front wall 1 10 illustratively defines two arcuate portions 1 10B, 1 10C separated by a center tab 1 10A. The arcuate portions 1 10B, 1 10C are illustratively sized to fit around the transmitter 62 and the receiver 64 respectively of the object detection sensor sub- assembly 52 when mounted to the housing 54. It will be understood that in alternate embodiments the housing 54 may include more or fewer bosses 102A-102D and/or more or fewer elongated clips 104A-104D.

[0045] Referring now to FIGS. 4A-4B, an embodiment of the frame or bracket 50 is shown which illustratively includes a rear wall 80, a front wall 86 and a bottom wall 84 extending between the rear wall 80 and the front wall 86. The front wall 80 and the rear wall 86 illustratively extend substantially parallel with one another and normally away from an inner surface 84A of the bottom wall 84. The rear wall 80 illustratively defines a number, e.g., two, of openings 82A, 82B therethrough, each spaced apart from a top edge 90 of the rear wall 80 and each sized to receive a conventional fixation member, e.g., a screw or bolt, therethrough to mount the frame or bracket 50 to the support frame 16 of the height-adjustable work table 12. The rear wall 80 further defines a pair of spaced-apart openings 95A, 95D therein sized to receive and engage the detents 1 14 defined at the free ends of the clips 104A, 104D respectively to secure the housing 55 to the frame or bracket 50.

[0046] The front wall 86 illustratively defines a top edge 88 which is disposed vertically between the bottom surface 84A of the bottom wall 84 and the top edge 90 of the rear wall 80 as best shown in FIG. 4A. The front wall 86 illustratively defines two arcuate portions 92, 94 separated by a center tab 96. The arcuate portions 92, 94 are illustratively sized to fit around the transmitter 62 and the receiver 64 respectively of the object detection sensor sub-assembly 52 opposite the arcuate portions 1 10B, 1 10C respectively of the housing 54, and the center tabs 96 and 1 10A are respectively sized to abut or form a space therebetween, when the combination of the housing 50 and the object detection sensor sub-assembly 52 mounted thereto are secured to the frame or bracket 50 as best illustrated in FIG.

2B. The front wall 86 further defines a pair of spaced-apart openings 95B, 95C therein sized to receive and engage the detents 1 14 defined at the free ends of the clips 104B, 104C respectively to secure the housing 50 to the frame or bracket 50 as also best illustrated in FIG. 2B.

[0047] The bottom wall 84 of the frame or bracket 50 illustratively defines a pair of spaced-apart openings each sized and positioned to receive a respective one of the transmitter 72 and the receiver 74 therethrough when the combination of the housing 50 and the object detection sensor sub-assembly 52 mounted thereto are secured to the frame or bracket 50 such that at least a portion of the transmitter 72 and at least a portion of the receiver 74 extend downwardly away from the bottom wall 84 of the frame or bracket 50 as best illustrated in FIGS. 2B and 2C. At least a portion of the transmitter 62 and at least a portion of the receiver 64 likewise extend through and away from the walls 86 and 1 10 of the frame or bracket 50 and housing 54 respectively when the combination of the housing 50 and the object detection sensor sub-assembly 52 mounted thereto are secured to the frame or bracket 50 as best illustrated in FIGS. 2A and 2C. With the combination of the housing 50 and the object detection sensor sub-assembly 52 mounted thereto are secured to the frame or bracket 50, the portion of the rear wall 80 defining the openings 82A, 82B therethrough are positioned above the outer surface 1 12A of the top wall 100 of the housing 54 so that the assembled object detection sensor assembly 36A may be mounted to the support frame 16 of the height-adjustable work table 12.

[0048] The housing 50 is illustratively configured such that the circuit board 76 and the electrically conductive pins 78 are suspended above the inner surface 84A of the bottom wall of the frame or bracket 50 when the combination of the housing 50 and the object detection sensor sub-assembly 52 mounted thereto are secured to the frame or bracket 50 as illustrated by example in FIG. 2C. In some embodiments, a lens 65 is fitted over and coupled to the receiver 64 as shown by example in FIGS. 2A-2C, although in other embodiments the lens 65 may be omitted. In embodiments which include it, the lens 65 may be configured to focus reflected radiation toward and/or into the radiation receiving element(s) of the receiver 64. Alternatively or additionally, the lens 65 may be merely protective, and in such embodiments the transmitter 62 may likewise be fitted with a lens.

[0049] The radiation detection signals sensed or detected by the radiation receivers 64, 74 illustratively include reflected radiation signals if the radiation emitted or transmitted by a respective transmitter 62, 72 is reflected by an object positioned within a sensing region of any of the object detection sensor assemblies 36A-36D, in accordance with a conventional time sequence in which at least one radiation transmitter 62, 72 is activated to emit radiation and at least a portion of such emitted radiation is reflected by the object toward and detected by at least one respective radiation detector 64, 74. As illustrated by example in FIG. 6 with respect to the radiation transmitter 62 and the radiation detector 64 of the object detection sensor assembly 36A, an object OB is detectable within an absolute sensing range ASR of the assembly 36A, where ASR is defined between a minimum axial sensing distance and a maximum axial sensing distance; that is, between a minimum distance away from the assembly 36A at which the object OB is horizontally and vertically aligned with the assembly 36A, i.e., directly opposite the assembly 36A, and at which the assembly 36A is able to detect the object OB and produce a corresponding object detection signal, and a maximum distance away from the assembly 36A at which the object OB is horizontally and vertically aligned with the assembly 36A, i.e., directly opposite the assembly 36A, and at which the assembly 36A is able to detect the object OB and produce a corresponding object detection signal. Within this absolute sensing range ASR, radiation signals 120 emitted by the radiation transmitter 62 propagate outwardly away from the assembly 36A, and at least a portion of such signals 120 which strike the object OB are reflected by the object OB back toward the assembly 36A in the form of reflected radiation signals 122 which are detected by the radiation detector 64. Outside of the absolute sensing range, the detection signal produced by the radiation detector 64 may be zero or below a detection threshold, or may be some other constant (baseline) value based on the particular implementation. The detection signal produced by the radiation detector 64 thus contains reflected radiation signals when an object is within ASR and contains no signal(s) or some other baseline signal(s) when an object is outside ASR. In some embodiments, the computing device within the module 32, 38 and/or within any sensor assembly may be programmed with a single baseline signal, e.g., baseline signal(s) detected by the various radiation detectors at any vertical position of the work top 14 relative to the floor 26 with no object(s) positioned between, or with multiple such baseline signals at two or more different vertical positions of the work top 14 relative to the floor 26, or any such computing device may be

programmed to learn any such single baseline signal or multiple baseline signals using one or more conventional learning algorithms. In any case, the radiation transmitter 72 and radiation detector 74 illustratively operate as just described.

[0050] In the case of the radiation transmitter 62 and radiation receiver 64 implemented in the form of the example ultrasonic range sensor described above, the absolute sensing range ASR between the assembly 36A mounted to the support frame 16 of the height-adjustable work table 12 and a detectable object OB is approximately 2 cm - 400 cm (or 1 inch - 13 feet). In the case of the radiation transmitter 72 and radiation receiver 74 implemented in the form of the example infrared (IR) transmitter and receiver diode pair described above, the absolute sensing range ASR between the assembly 36A mounted to the support frame 16 of the height-adjustable work table 12 and a detectable object OB is illustratively approximately 2 cm - 2 m (or 1 inch - 6.5 feet). It will be understood, however, that the transmitter 62 and receiver 64 pair and/or the transmitter 72 and receiver 74 pair may be provided in other conventional forms operating in any frequency range, and the absolute sensing range(s) ASR of such alternate transmitter/receiver pairs may accordingly be different from the examples provide above.

[0051] Referring again to FIGS. 1 A-1 D, the object detection sensor

assemblies 36A, 36B are illustratively mounted, in spaced-apart relationship to one another, to the lateral or transverse table support member 28A between the front end thereof and the axial support member 20A as best illustrated in FIG. 1 D via conventional fixation members, e.g., screws or bolts or the like, 85A, 85B extending through the respective openings 82A, 82B of the back wall 80 of the frame or bracket 50 and into engagement with the table support member 28A. The object detection sensor assemblies 36C, 36D are likewise illustratively mounted to the lateral or transverse table support member 28B as best illustrated in FIGS. 1 B and 1 C. In alternate embodiments, one or more of the object detection sensor assemblies 36A- 36D may be mounted to one or more other components of the support frame 16 and/or to the underside 14B of the work top 14

[0052] In the orientation of the mounted object detection sensor assemblies 36A-36D relative to the height-adjustable work table 12 just described, the radiation patterns transmitted by the radiation transmitters 62 of the respective object detection sensor assemblies 36A-36D is generally parallel with the planar

undersurface 14B of the work top 14, or parallel with the planar support surface, e.g., floor, 26 supporting the work table 12 in embodiments in which the undersurface 14B of the work top 14 is not planar. Such radiation patterns 37A-37C of respective object detection sensor assemblies 36A-36C are illustrated by example in FIGS. 1 B- 1 D. As further illustrated in FIGS. 1 B and 1 D, each radiation transmitter 62 illustratively produces radiation having a circular cross-section with radius R which varies as a function of the distance from the transmitter 62 and the angle B of radiation transmission by and from the transmitter 62 such that the transmitted radiation patterns are conical in shape. In embodiments in which the radiation transmitters 62 are implemented in the form of the ultrasonic range sensor described above, B is approximately 30 degrees, although it will be understood that in other embodiments transmitters 62 may be selected which transmit radiation at angles having other values of B.

[0053] In the orientation of the mounted object detection sensor assemblies 36A-36D relative to the height-adjustable work table 12 described above and illustrated in FIGS. 1 A-1 D, the radiation patterns transmitted by the radiation transmitters 72 of the respective object detection sensor assemblies 36A-36D are generally normally away from the undersurface 14B of the work top 14 toward the support surface, e.g., floor, 26 supporting the work table 12. Such radiation patterns 72A-72C of respective object detection sensor assemblies 36A-36C are illustrated by example in FIGS. 1 A and 1 C. As further illustrated in FIG. 1 A, each radiation transmitter 72 illustratively produces radiation having a circular cross-section with a radius which is a function of the distance from the transmitter 72 and of the angle A of radiation transmission by and from the transmitter 72 such that the transmitted radiation patterns are conical in shape. In embodiments in which the radiation transmitters 72 are implemented in the form of the IR diode emitters described above, A is approximately 40 degrees, although it will be understood that in other embodiments transmitters 72 may be selected which transmit radiation at angles having other values of A. The angles A and B will be understood to be the radius of radiation beam spreading relative to a central longitudinal axis of the radiation beam.

[0054] As best illustrated in FIG. 1 C with reference to the illustrated radiation patterns 37A, 37C, the object detection sensor assemblies 36A-36D are positioned relative to the support frame 16 of the height-adjustable work table 12 such that the radiation patterns of the radiation transmitters 62 intersect approximately under an imaginary center line C transversely bisecting the work top 14 at a distance D1 below the underside 14B of the work top 14, and such that the radiation patterns of the radiation transmitters 62 each intersect an oppositely positioned adjustable column member 22A, 22B at a distance D2 below the underside 14B of the work top 14. In embodiments in which the radiation transmitters 62 are implemented in the form of the ultrasonic range sensor described above, D1 is approximately 4-4.5 inches and D2 is approximately 7-7.5 inches, although in other embodiments the system may be designed to achieve other values of D1 and/or D2. It will be understood that any such alternate design would be a mechanical step to a skilled artisan based on the concepts illustrated in the attached drawings and described herein.

[0055] As also best illustrated in FIG. 1 C with reference to the illustrated radiation patterns 72A, 72C, the object detection sensor assemblies 36A-36D are positioned relative to the support frame 16 of the height-adjustable work table 12 such that the radiation patterns of the radiation transmitters 72 intersect the support surface 26, e.g., floor, with a diameter D3, wherein D3 is a function of the distance between the transmitters 72 and the support surface 26 as well as the radiation angle A of the transmitters 72. With the top surface 14A of the work top 14 of the height-adjustable work table 12 at its maximum height, e.g., approximately 50 inches, and in embodiments in which the radiation transmitters 72 are implemented in the form of the IR diode emitters described above, D3 is approximately 32 inches, although in other embodiments the system may be designed to achieve other values of D3. It will be understood that any such alternate design would be a mechanical step to a skilled artisan based on the concepts illustrated in the attached drawings and described herein. In any case, the radiation patterns 72A-72C, including any and all intersections thereof, illustratively represent and define individual sensing ranges SR as well as a collective sensing range SR of the pairs 72, 74 radiation transmitters and receivers of the object detection sensor assemblies 36A-36D as described above with respect to FIG. 6.

[0056] Referring now to FIG. 7A, a block diagram schematic is shown of an embodiment of the system 10 for preventing contact between the work top 14 of the table 12 and an object disposed under the work top 14. In the embodiment illustrated in FIG. 7A, the system 10 illustratively includes both the main control module 32 and the impact avoidance control module 38 depicted in FIGS. 1 A and 1 B. As described above, the main control module 32 illustratively houses at least one computing device operatively coupled to the drive motors 152A, 152B, e.g., via any number K of signal paths, wherein K may be any positive integer, and to a user interface module 35, and is configured, i.e., programmed, to control operation of the drive motors 152A, 152B in a conventional manner based on user interaction with the user interface module 35. Illustratively, the main control module 32 includes one or more memory units, e.g., in the form of one or more non-transitory machine or computing device readable media, having instructions stored therein which, when executed by the at least one computing device, causes the at least one computing device to carry out, i.e., control execution and/or operation of, the drive motors 152A, 152B and the main control module 35 as just described. An example embodiment of the main control module 32 is illustrated in FIG. 7B.

[0057] The main control module 32 is operatively coupled to the impact avoidance control module 38 via a number M of signal path, wherein M may be any positive integer. In some embodiments, the impact avoidance control module 38 receives electrical power from the main control module 32 and in such embodiments at least one of the M signal paths carries such electrical power. In some such embodiments, the electrical power received from the main control module 32 is of a type that is not appropriate, e.g., in magnitude and/or type, for powering the module 38 and/or the one or more sensors 36A-36D (e.g., the one or more object detection sensor assemblies 36A-36D), and in such embodiments the impact avoidance control module 38 illustratively includes a conventional power conversion circuit 130 configured to convert the electrical power provided by the main control module 32 to suitable electrical power for powering an on-board communication circuit 132 and/or an on-board computing device 140, and/or for powering the one or more sensors 36A-36D. In some such embodiments, the power conversion circuit 130 may include conventional circuitry for converting a higher-magnitude AC or DC voltage and/or current to a lower magnitude AC or DC voltage and/or current, for converting a lower-magnitude AC or DC voltage and/or current to a higher magnitude AC or DC voltage and/or current, and/or for converting voltage and/or current from one type to another, e.g., from AC to DC or vice versa.

[0058] In some embodiments, the impact avoidance control module 38 is configured to communicate with the main control module 32 using communication signals with any conventional communication protocol, and in such embodiments at least one of the M signal paths is configured to carry such communication signals. In such embodiments, the impact avoidance control module 38 includes a communication circuit 132 and the main control module 32 likewise includes a communication circuit configured to communicate with the communication circuit 130 via any conventional communication protocol. In alternate embodiments, the communication circuit 130 and the communication circuit carried by the main control module 32 may be configured to communicate wirelessly, and in such embodiments respective one(s) of the M signal paths may be omitted.

[0059] In some embodiments, each of the one or more sensors 36A-36D (e.g., the one or more object detection sensor assemblies 36A-36D) is operatively coupled to the impact avoidance control module 38 via one or more of a number N of signal paths, wherein N may be any positive integer. In embodiments in which the one or more sensors 36A-36D receive electrical power from the module 38, at least one of the number N of signal paths carries such electrical power. In some alternate embodiments, one or more of the sensors 36A-36D may receive electrical power from the main control module 32. In other alternate embodiments, one or more of the sensors 36A-36D may be self-powered, i.e., may include a self-contained source of electrical power, e.g., one or more batteries, and in such embodiments a corresponding one or more of the electrical power-carrying ones of the N signal paths may be omitted. In some embodiments, the impact avoidance control module 38 is configured to communicate with the one or more sensors 36A-36D and vice versa via respective ones of the N signal paths. In some alternate embodiments, one or more of the sensors 36A-36D may carry wireless communication circuitry, and in such embodiments the communication circuit 132 may be configured to conduct wireless communications with one or more of the sensors 36A-36D. In such embodiments, respective one(s) of the N signal paths may be omitted.

[0060] In the illustrated embodiment, the impact avoidance control module 38 includes a computing device 140 and a memory unit 142. The computing device 140 is illustratively conventional and may be provided in the form of one or more conventional microprocessors, one or more controllers or the like. In such

embodiments, the memory unit 142 is likewise illustratively conventional and may be provided in the form of one or more conventional non-transitory machine-readable, i.e., computing device readable, media having instructions stored therein which, when executed by the computing device 140, cause the computing device 140 to control the one or more sensors 36A-36D and monitor signals produced by the one or more sensors 36A-36D, to determine, based on such sensor signals, whether an object disposed thereunder is within the sensing range SR of one or more of the sensors 36A-36D and, if so, to communicate a suitable message to the main control module 32. In this embodiment, the computing device of the main control module 32 is illustratively responsive to the received message to control the drive motors 152A, 152B to stop movement of the height-adjustable column members 22A, 22B if moving downwardly or to disable downward movement of the height-adjustable column members 22A, 22B if not moving. An example process, which may be stored in the memory 142 in the form of instructions executed by the computing device 140, for carrying out these functions just described is illustrated in FIG. 8 and will be described in detail below.

[0061] Referring now to FIG. 7B, an alternate embodiment of the system 10’ is shown in which the impact avoidance control module 38 is omitted, the main control module 32 is operatively coupled to the one or more sensors 36A-36D and the functions described above as being carried out by the impact avoidance control module 38 are carried out by the main control module 32. Each of the drive motors 152A, 152B is operatively coupled to the main control module 32 via one or more of the K signal paths as described above with respect to FIG. 7A. In some

embodiments, each of the one or more sensors 36A-36D (e.g., the one or more object detection sensor assemblies 36A-36D) is operatively coupled to the main control module 32 via one or more of a number L of signal paths, wherein L may be any positive integer. In embodiments in which the one or more sensors 36A-36D receive electrical power from the module 32, at least one of the number L of signal paths carries such electrical power. In some alternate embodiments, one or more of the sensors 36A-36D may be self-powered, i.e., may include a self-contained source of electrical power, e.g., one or more batteries, and in such embodiments a corresponding one or more of the electrical power-carrying ones of the L signal paths may be omitted. In some embodiments, a communication circuit 132 of the main control module 32 is configured to communicate with the one or more sensors 36A- 36D and vice versa via respective ones of the L signal paths. In some alternate embodiments, one or more of the sensors 36A-36D may carry wireless

communication circuitry, and in such embodiments the communication circuit 132 may be configured to conduct wireless communications with one or more of the sensors 36A-36D. In such embodiments, respective one(s) of the L signal paths may be omitted. [0062] In the illustrated embodiment, the main control module 32 includes a computing device 160 and a memory unit 162. The computing device 160 is illustratively conventional and may be provided in the form of one or more

conventional microprocessors, one or more controllers or the like. In such embodiments, the memory unit 162 is likewise illustratively conventional and may be provided in the form of one or more conventional non-transitory machine-readable, i.e., computing device readable, media having instructions stored therein which, when executed by the computing device 160, cause the computing device 160 to control operation of the drive motors 152A, 152B in a conventional manner based on user interaction with the user interface module 35, and to execute all impact avoidance functions described above with respect to FIG. 7A. More specifically, in the embodiment illustrated in FIG. 7B, the computing device 160 is operable to control the one or more sensors 36A-36D and monitor signals produced thereby the one or more sensors 36A-36D, to determine, based on such sensor signals, whether an object disposed thereunder is within the sensing range SR of one or more of the sensors 36A-36D, and to control the drive motors 152A, 152B to stop movement of the height-adjustable column members 22A, 22B if moving downwardly or to disable downward movement of the height-adjustable column members 22A, 22B if not moving. An example process, which may be stored in the memory 162 in the form of instructions executed by the computing device 160, for carrying out these functions just described is illustrated in FIG. 8 and will be described in detail below.

[0063] The main control module 32 further illustrative includes a power conversion circuit 150 for converting electrical power from an incoming source (not shown), e.g., from a conventional wall outlet of a residential or commercial building, to electrical power suitable for use by the communication circuit 132, the computing device 160, the drive motors 152A, 152B and the one or more sensors 36A-36D. In some embodiments, the power conversion circuit 150 includes conventional driver circuitry coupled to the computing device 160 and to each of the drive motors 152A, 152B via which the computing device 160 can control operation of the drive motors 152A, 152B to raise or lower the work top 14 as described above. In alternate embodiments, such driver circuitry may be separate from, but operatively coupled to, the power conversion circuit 150. In some such embodiments, the power conversion circuit 150 may include conventional circuitry for converting a higher- magnitude AC or DC voltage and/or current to a lower magnitude AC or DC voltage and/or current, for converting a lower-magnitude AC or DC voltage and/or current to a higher magnitude AC or DC voltage and/or current, and/or for converting voltage and/or current from one type to another, e.g., from AC to DC or vice versa. In some embodiments in which the one or more sensors 36A-36D receive electrical power from the main control module 32, at least one of the number L of signal paths carries such electrical power. In some alternate embodiments, one or more of the sensors 36A-36D may be self-powered, i.e., may include a self-contained source of electrical power, e.g., one or more batteries, and in such embodiments a corresponding one or more of the electrical power-carrying ones of the L signal paths may be omitted. In some embodiments, the communication circuit 132 is configured to communicate with the one or more sensors 36A-36D and vice versa via respective ones of the L signal paths. In some alternate embodiments, one or more of the sensors 36A-36D may carry wireless communication circuitry, and in such embodiments the

communication circuit 132 may be configured to conduct wireless communications with one or more of the sensors 36A-36D. In such embodiments, respective one(s) of the L signal paths may be omitted.

[0064] Referring now to FIG. 8, a simplified flowchart is shown of an embodiment of a process 200 for carrying out the impact avoidance features briefly described above with respect to FIGS. 7A and 7B. In the illustrated embodiment, the process 200 illustratively includes two separate process legs 202 and 204. In embodiments in which the system 10 takes the form of that shown in FIG. 7A, the control operations of the process leg 202 are illustratively stored in the memory 142 of the computing device 140 of the impact avoidance control module 38 in the form of instructions executable by the computing device 140, and the control operations of the process leg 204 are illustratively stored in the memory of the computing device of the main control module 32 in the form of instructions executable by the computing device of the main control module. In embodiments in which the system 10 takes the form of that 10’ shown in FIG. 7B, all of the control operations of the process 200, including those of the process leg 202 and of the process leg 204, are illustratively stored in the memory 162 of the computing device 160 of the main control module 32 in the form of instructions executable by the computing device 160. In still other embodiments in which one or more of the sensor assemblies 36A- 36D includes a computing device and memory as described above, some of the control operations of the process leg 202 are illustratively stored in the memory of the computing device of the sensor assembly(s) 36A-36D in the form of instructions executable by the computing device thereof. Other control operations of the process leg 202 in such embodiments may be carried out by the computing device of the impact avoidance control module 38, in embodiments which include it, or by the computing device of the main control module 32. In any case, the control operations of the process leg 204 are illustratively stored in the memory of the computing device of the main control module 32 in the form of instructions executable by the computing device of the main control module.

[0065] The process leg 202 is illustratively executed continually, i.e., in a continuously repeating loop. The following control operations of the process leg 202 will be described as being executed by the computing device 140 or 160, although it will be understood that in some embodiments in which one or more of the sensor assemblies 36A-36D include computing devices as described above, some of the control operations of the process leg 202 may be executed by the computing device(s) of one or more of the sensor assemblies 36A-36D. The process leg 202 illustratively begins at step 210 where the computing device 140, 160 is operable to activate the sensors 36A-36D and log the resulting sensor readings a number N of times, where N may be any positive integer. In one embodiment, the computing device 140, 160 is operable to execute step 210 by activating the radiation transmitter 62 and/or the radiation transmitter 72 of one or more (or all) of the object detection sensor assemblies 36A-36D to transmit radiation and activating the radiation receiver 64 and/or the radiation receiver 74 of one or more (or all) of the object detection sensor assemblies 36A-36D and logging radiation detection signal(s) detected thereby. Any detection signal(s) will include reflected radiation signal(s) if at least a portion of a transmitted radiation signal is reflected by an object within the sensing range SR thereof back to a respective radiation receiver(s) 64/74 and is detected thereby, and such detection signals may be referred to herein as object detection signals. If no object reflects any portion of a transmitted radiation signal back to a respective radiation receiver(s) 64/74, the corresponding detection signal(s) will be zero, below some threshold level, at some constant value or at one or more baseline values depending upon the implementation of the table 12 and/or on the height of the work top 14 relative to the floor 26 as described above. In any case, the detection signals are illustratively logged by storing the one or more detection signals in a buffer of the memory unit 142, 162. In one embodiment, the activation of the sensor(s) 36A-36D and logging the detection signal(s) illustratively occurs 10 times, although in alternate embodiments N may be less than or greater than 10.

[0066] Following step 210, the process leg 202 advances to step 212 where the computing device 140, 160 is operable to process the logged sensor readings to determine whether an object is within a sensing range SR of one or more of the object detection sensor assemblies 36A-36D, i.e., to determine whether any of the detection signals include object detection signals. As briefly described above with respect to FIG. 6, the computing device 140, 160 is illustratively operable to execute step 212 by computing a time difference between the time of activation of each radiation transmitter 62, 72 and the time of detection by a respective radiation receiver 64, 74 of a reflected radiation signal, if any. The distance between a detectable object and any of the object detection sensor assemblies 36A-36D is a function of this computed time difference for a radiation transmitter/receiver pair 62/64, 72/74. The maximum detectable distance between an object and any of the object detection sensor assemblies 36A-36D is the absolute sensing range ASR of the respective object detection sensor assembly 36A-36D as described above with respect to FIG. 6.

[0067] However, a lesser sensing range may be defined for any radiation transmitter/receiver pair 62/64, 72/74 by restricting the allowable range of computed time difference values. Referring again to FIG. 1 C, for example, a sensing range SR1 may be established for the transmitter/receiver pair 62/64 of any object detection sensor assembly 36A-36D by restricting or limiting the allowable range of computed time difference values to a maximum computed time difference value which corresponds to the distance between the transmitter/receiver pair 62/64 and the transverse center line C of the work top 14. By so restricting the allowable range of computed time difference values in this manner, the effective sensing range SR of the respective transmitter/receiver pair 62/64 is SR1 . As another example, a sensing range SR2 may be established for the transmitter/receiver pair 62/64 of any object detection sensor assembly 36A-36D by restricting or limiting the allowable range of computed time difference values to a maximum computed time difference value which corresponds to the distance between the transmitter/receiver pair 62/64 and the inwardly-facing side of the height-adjustable column member 22A, 22B opposite the transmitter/receiver pair 62/64. By so restricting the allowable range of computed time difference values in this manner, the effective sensing range SR of the respective transmitter/receiver pair 62/64 is SR2.

[0068] The sensing ranges SR of the transmitter/receiver pairs, together with the positions thereof relative to the underside 14B of the work top 14 and the angles of radiation transmission by and from the radiation transmitters, effectively creates a radiation envelop adjacent to the underside 14B of the work top 14 that sets a predefined distance from the underside 14B of the work top 14 within which objects will be detected. It follows then that the sensing ranges SR, mounting positions and radiation transmission angles can be selected to establish a resulting radiation envelop within which an object within any desired predefined distance of the underside 14B of the work top 14 will be detected. The desired predefined distance for any particular implementation of the system 10 is thus programmed, i.e., stored in the respective memory unit 142, 162, by programming, i.e., storing in the respective memory unit 142, 162, a restricted sensing range via appropriate selection of the maximum computed time difference value(s), taking into account the mounting positions of the sensor assemblies 36A-36D and their radiation transmission angles. Examples of such radiation envelops are depicted in FIGS. 9-10B and described in further detail below.

[0069] In one embodiment of the example system 10, 10’ illustrated in FIGS.

1 A-7B, the sensing range SR of each transmitter/receiver pair 62/64 of each object detection sensor assembly 36A-36D is set to SR1 , as illustrated by example in FIG. 1 C. Illustratively, SR1 is established by storing a maximum computed time difference value for each transmitter/receiver pairs 62/64 pair in the memory 142 or 162, wherein the stored maximum computed time difference value corresponds to the computed time difference value at which a detected object is positioned at or near the transverse center line C of the work top 14. At step 212, the computing device 140, 160 is thus operable to process the logged sensor readings to determine whether an object is within a sensing range SR of one or more of the object detection sensor assemblies 36A-36D by comparing the respective computed time difference values to a restricted range of computed time difference values bound by a minimum computed time difference, e.g., corresponding to a minimum detection distance, and the stored maximum computed time difference value. If a computed time difference value is within the restricted range of computed time difference values, the computing device 140, 160 determines at step 212 that an object is detected within the sensing range SR, and otherwise the computing device 140, 160 determines at step 212 that an object is not detected within the sensing range SR.

In alternate embodiments, the defined or established sensing range SR of the transmitter/receiver pair 62/64 of one or more of the object detection sensor assemblies 36A-36D may be greater or less than SR1 .

[0070] The sensing range of each transmitter/receiver pair 72/74 of each object detection sensor assembly 36A-36D is likewise illustratively set to a selected distance below the respective object detection sensor assembly 36A-36D. In one embodiment, the selected distance is 3-4 inches, although in other embodiments the selected distance may be greater or less than 3-4 inches.

[0071] In one embodiment, the computing device 140, 160 illustratively bases the object detection determination just described on an average of the N stored sensor readings for each transmitter/receiver pair 62/64, 72/74 of each object detection sensor assembly 36A-36D. In this embodiment, a sequence of N time difference measurements are logged for each transmitter/receiver pair 62/64, 72/74, and the N logged time difference measurements for each transmitter/receiver pair 62/64, 72/74 are then averaged together, e.g., using a conventional algebraic averaging technique, and it is the average time difference value that is used to determine whether an object is within the sensing region of that transmitter/receiver pair 62/64, 72/74. In alternate embodiments, a determination of whether an object is within the sensing region of a transmitter/receiver pair 62/64, 72/74 may be made for each of the N time difference measurements for that pair 62/64, 72/74, and an ultimate determination that an object is within the sensing region of the pair 62/64, 72/74 may be a function of the N individual determinations. For example, an ultimate determination of that an object is within the sensing region of the pair 62/64, 72/74 may be made if some number M of the N individual determinations indicate that an object is within the sensing region, where M < N. As another example, an ultimate determination of that an object is within the sensing region of the pair 62/64, 72/74 may be made if some number M of the most recent N individual determinations indicate that an object is within the sensing region, where M < N. Those skilled in the art will recognize other conventional techniques for making an ultimate determination of whether an object is within the sensing region of a

transmitter/receiver pair 62/64, 72/74 of any of the object detection sensor assemblies 36A-36D based on the N time difference measurements made for that pair 62/64, 72/74, and it will be understood that all such other conventional techniques fall within the scope of this disclosure. In any case, the process leg 202 of the process 200 advances from step 212 to step 214.

[0072] At step 214, the computing device 140, 160 tests the object detection result of step 212. If an object was not detected within the sensing range SR of one or more of the object detection sensor assemblies 36A-36D at step 212, execution of the process leg 202 advances to step 218. If, on the other hand, an object was detected within the sensing range SR of one or more of the object detection sensor assemblies 36A-36D at step 212, the process advances to step 216 where the computing device 140, 160 sets an object detection flag. In embodiments in which the system 10 is implemented in the form illustrated in FIG. 7A, the computing device 140 executes steps 210-220, and in such embodiments the computing device 140 is further operable at step 216 to transmit the object detection flag or a message containing the present“set” state of the object detection flag, to the main control module, e.g., via the communication circuit 132. In any case, execution of the process leg 202 loops from step 216 back to step 210.

[0073] If, at step 212, an object was not detected within the sensing range SR of one or more of the object detection sensor assemblies 36A-36D, the process advances to step 218 where the computing device 140, 160 determines whether the object detection flag is currently set. If not, execution of the process leg 202 loops back to step 210. If, at step 218 the computing device 140, 160 determines that the object detection flag is currently set, the process leg 202 advances to step 220 where the computing device 140, 160 is operable to clear the object detection flag.

In embodiments in which the system 10 is implemented in the form illustrated in FIG. 7A, the computing device 140 executes steps 210-220, and in such embodiments the computing device 140 is further operable at step 220 to transmit the object detection flag or a message containing the present“cleared” state of the object detection flag, to the main control module, e.g., via the communication circuit 132. In any case, execution of the process leg 202 loops from step 220 back to step 210.

[0074] The process leg 204 of the process 200 depicted in FIG. 8 is illustratively executed continually, i.e., in a continuously repeating loop. The process leg 204 illustratively begins at step 230 where the computing device 160 is operable to determine whether the work top 14 of the height-adjustable work table 12 is stationary. The computing device 160 is operable, as described above, to control operation of the drive motors 152A, 152B based on signals produced by the user interface 35, and the work top 14 is moving if the height-adjustable column members 22A, 22B are being driven upwardly or downwardly by the respective drive motors 152A, 152B. Thus, the work top 14 is moving if the computing device 160 is activating the drive motors 152A, 152B, and the work top 14 is not moving if the computing device 160 is not activating the drive motors 152A, 152B. If the computing device 160 determines at step 230 the work top 14 is stationary, execution of the process leg 204 advances to step 238. If the computing device 160 instead determines at step 230 that the work top 214 is moving, i.e., that the computing device 160 is activating the drive motors 152A, 152B, the process leg 204 advances to step 232 where the computing device 160 is operable to determine whether the work top 14 is moving upwardly or downwardly, i.e., whether the computing device 160 is controlling the drive motors 152A, 152B to drive the height- adjustable columns 22A, 22B upwardly or downwardly. If upwardly, the process leg 204 loops back to step 230. If downwardly, however, execution of the process leg 204 advances to step 234.

[0075] At step 234, the computing device 160 has determined that the work top 14 is moving downwardly, i.e., that the computing device 160 is presently controlling the drive motors 152A, 152B to drive the height-adjustable column members 22A, 22B downwardly, e.g., to a more compact height of the telescoping column members 22A, 22B, the computing device 160 is operable to determine the state of the object detection flag. In embodiments in which the process leg 202 is executed by the computing device 140 of the impact avoidance control module 38, the computing device 160 has received the most current object detection flag or message containing he most current state of the object detection flag transmitted thereto by the computing device 140, and has stored the flag or state thereof in a buffer or other storage location of the memory unit 162. In embodiments in which the process leg 202 is executed by the computing device 160, the most current object detection flag or state thereof has been stored by the computing device 160 in the buffer or other storage location of the memory unit 162. In either case, the computing device 160 is thus operable at step 234 to determine whether the object detection flag is currently set by recalling the most recently stored object detection flag or state thereof from the buffer or other storage location of the memory unit 162. If the object detection flag is not set, execution of the process leg 204 loops back to step 232 to continue to monitor the movement of the work top 14 if any. If the computing device 160 determines at step 234 that the object detection flag is currently set, execution of the process leg 204 advances to step 236 where the computing device 160 is operable to stop the downward movement of the work top 14 by deactivating the drive motors 152A, 152B so that the drive motors 152A, 152B stop driving movement of the height-adjustable columns 22A, 22B downwardly. Thereafter, execution of the process leg 204 loops back to step 230. If the object detection flag has been cleared from a set state following execution of step 236, the NO branch of step 238 following subsequent execution of step 230 illustratively follows the dashed line path to step 242 which will be described below.

[0076] If, at step 230, the computing device 160 has determined that the work top 14 is stationary, i.e., that the computing device 160 is not presently activating the drive motors 152A, 152B, execution of the process leg 204 advances to step 238 where the computing device 160 is operable to determine the current state of the object detection flag as described above with respect to step 234. If not currently set, execution of the process leg 204 loops back to step 230. If currently set, execution of the process leg 204 advances to step 240 where the computing device 160 is operable to disable downward movement of the work top 14 by either disabling the drive motors 152A, 152B so that they cannot drive movement of the height-adjustable columns 22A, 22B downwardly, i.e., to a more compact height thereof, or by disregarding any command received by the user interface 35 to lower the height of the work top 14.

[0077] Following step 240, the process leg 204 advances to step 242 where the computing device 160 is again operable to determine the current state of the object detection flag as described above with respect to step 234. If not currently set, execution of the process leg 204 loops back to step 230. If the object detection flag is determined at step 242 to still be set, execution of the process leg 204 loops back to step 230. If the object detection flag is determined at step 242 to be cleared, execution of the process leg 204 advances to step 244 where the computing device 160 is operable to enable or allow downward movement of the work top 14 by either enabling the drive motors 152A, 152B so that they can drive movement of the height- adjustable columns 22A, 22B downwardly, i.e., to a more compact height thereof, or by acting on any command received by the user interface 35 to lower the height of the work top 14. Thereafter, execution of the process leg 204 loops back to step 230.

[0078] The process 200 of FIG. 8 has been described as being executed, in some embodiments, in its entirety by the computing device 160 of the main control module 32, and in other embodiments by a combination of the computing device 140 of the impact avoidance control module 38 (e.g., executing the control operations of the process leg 202) and the computing device 160 of the main control module 32 (e.g., executing the control operations of the process leg 204). As briefly described above, however, some embodiments of the sensor assemblies 36A-36D may include computing devices which may be programmed to execute at least some of the control operations of process leg 202 of the process 200 illustrated in FIG. 8. As one example in which the system 10 does not include the impact avoidance module 38 and in which each of the sensor assemblies 36A-36D includes at least a computing device and an associated memory unit, such memory units may include instructions executable by the respective computing device to execute steps 210-214 such that each sensor assembly 36A-36D is operable to determine whether an object is within the restricted sensing range thereof, i.e., whether the object is within a predefined distance of the underside 14B of the work top 14, such that the object detection signal produced thereby is a direct determination that the object is detected, i.e., that the object is within the programmed predefined distance from the underside 14B of the work top 14. Alternatively or in addition to steps 216-220, the memory units of the sensor assemblies 36A-36B may include instructions to communicate the object detection flag to the computing device 160 or to omit setting and clearing an object detection flag and simply communicate the present object detection signal state to the computing device 160. As another example in which the system 10 includes the impact avoidance module 38 and in which each of the sensor assemblies 36A-36D includes at least a computing device and an associated memory unit, such memory units may include instructions executable by the respective computing device to execute steps 210-220 as just described but with the object detection signal communicated to the computing device 140 of the impact avoidance control module 38. In this embodiment, the process leg 202 will include additional steps, e.g., similar or identical to the original steps 216-220 depicted in FIG. 8, to communicate the object detection information from the computing device 140 of the impact avoidance control module 38 to the main control module 32. In some variants, only one or a subset of the sensor assemblies 36A-36D (or only one or a subset of the transmitter/receiver pairs) may operate as just described, and the remaining sensor assemblies (or transmitter/receiver pairs) and the computing device 140, 160 may operate according to the original steps of the process 200 illustrated in FIG. 8 and described above.

[0079] Referring now to FIG. 9, an example is shown illustrating operation of steps 230, 238 and 240 of the process leg 204 of the process 200 of FIG. 8. In the illustrated example, the work top 14 of the height-adjustable work table 12 is stationary and a chair CH is positioned under the work top 14. In this example, which should not be considered to be limiting in any way, the sensing range of the transmitter/receiver pair 62/64 of each object detection sensor assembly 36A-36D is restricted to the distance between the respective object detection sensor assembly 36A-36D and the transverse center line C of the work top 14. The sensing range SRA of the transmitter/receiver pair 62/64 of the object detection sensor assembly 36A illustrated in FIG. 9 is thus the portion of the radiation pattern 37A extending between the object detection assembly 36A and a plane P defined by the transverse center line C, and the sensing range SRc of the transmitter/receiver pair 62/64 of the object detection sensor assembly 36C is the portion of the radiation pattern 37C extending between the object detection assembly 36C and the plane P. The radiation envelop created by the overlapping sensing ranges SRA and SRc in FIG. 9 is bounded at the top by the underside 14B of the work top 14 and at the bottom by the lower, overlapping peripheries of the radiation patterns 37A and 37C (along with the lower, overlapping peripheries of similar radiation patterns produced by the sensor assemblies 36B and 36D) establish the predefined distance from the underside 14B of the work top 14 within which an object will be detected by the system 10. Similar radiation envelops are established by the radiation transmitters 72 of the sensor assemblies 36A-36D.

[0080] The processor 140, 160 executing the process leg 202 of the process 200 of FIG. 8 has set the object detection flag at step 216 because the object, i.e., a top portion T of the backrest of the chair CH, is determined at step 212 to be within the sensing region SRc of the object detection sensor assembly 36C, i.e., the top T of the chair CH is within the radiation envelop defined by the overlapping radiation patterns 37A, 37C (and/or by the overlapping peripheries of similar radiation patterns produced by the sensor assemblies 36B and 36D). Because the work top 14 is stationary, the process leg 204 advances from step 230 to step 238 and then to step 240 where the computing device 160 is operable to disable downward movement of the work top 14 as described above. Such disablement of downward movement of the work top 14 is maintained until the chair CH is removed from beneath the work top 14, until the chair CH is lowered until no portion of the chair extends into the sensing range SRc or the sensing range of any of the object detection sensor assemblies 36A-36D or unless the work top 14 is raised, pursuant to a command received from the user interface 35 to raise the height of the work top 14, until no portion of the chair extends into the sensing range of any of the object detection sensor assemblies 36A-36D. When any such scenario occurs, the computing device 140, 160 executing the process leg 202 will reset the object detection flag, and the computing device 160 will enable downward movement of the work top 14 at steps 242 and 244 of the process leg 204 following the dashed-line path illustrated in FIG. 8.

[0081] Referring now to FIGS. 10A and 10B, an example is shown illustrating operation of steps 230-236 of the process leg 204 of the process 200 of FIG. 8. In the example illustrated in FIG. 10A, the work top 14 of the height-adjustable work table 12 is stationary and an object OB is positioned under the work top 14. In this example, which should not be considered to be limiting in any way, the sensing range SRA of the transmitter/receiver pair 62/64 of the object detection sensor assembly 36A is the portion of the radiation pattern 37A extending between the object detection assembly 36A and a plane P defined by the transverse center line C, and the sensing range SRc of the transmitter/receiver pair 62/64 of the object detection sensor assembly 36C is the portion of the radiation pattern 37C extending between the object detection assembly 36C and the plane P, as described above with respect to the example illustrated in FIG. 9. In this example, the processor 140, 160 executing the process leg 202 of the process 200 of FIG. 8 has not set the object detection flag because no portion of the object OB is determined at step 212 to be within the sensing region of any of the object detection sensor assemblies 36A- 36CD. Because the work top 14 is stationary, the process leg 204 advances from step 230 to step 238 and then back to step 230 as the object detection flag remains cleared.

[0082] At some point, the computing device 160, acting on a command received from the user interface 35 to lower the height of the work top 14, activates the drive motors 152A, 152B to lower the height-adjustable column members 22A, 22B, i.e., to a more compact configuration. The process leg 204 advances from step 230 to step 232 and then to step 234 as the computing device 160 determines that the work top 14 is moving downwardly. Initially, all portions of the object OB are below the sensing region of each of the object detection sensor assemblies 36A- 36CD as depicted in FIG. 10A, and the process leg 202 thus loops from step 234 back to step 232. Eventually, the continued downward movement DN of the work top 14 causes at least the sensing regions SRA and SRc of the object detection sensor assemblies 36A and 36C to drop below the top T of the object OB such that a portion of the object OB extends into the radiation envelop defined by the

overlapping radiation patterns 37A, 37C of the sensing regions SRA and SRc as depicted in FIG. 10B. At this point, the computing device 140, 160 executing the process leg 202 sets the object detection flag, and the computing device 160 executing the process leg 204 thus advances from step 234 to step 236 where the computing device 160 is operable to stop the downward movement DN of the work top 14 by deactivating downward drive of drive motors 152A, 152B, thereby stopping the downward movement DN of the work top 14 before the underside 14B contacts the object OB. Such deactivation of the downward drive of the drive motors 152A, 152B is maintained until the object OB is removed from beneath the work top 14 or unless the work top 14 is sufficiently raised, pursuant to a command received from the user interface 35, to a height of the work top 14 at which no portion of the object OB extends into the sensing range of any of the object detection sensor assemblies 36A-36D. When either scenario occurs, the process leg 202 will reset the object detection flag, and the computing device 160 will enable downward movement of the work top 14 via successive execution of steps 230, 238 and 242-244 (following the dashed-line flow path).

[0083] The embodiment of the system 10, 10’ is illustrated in FIGS. 1 -10B and described above as being implemented with one example height-adjustable work table 12. In alternate embodiments, the system 10, 10’ may be implemented with other height-adjustable work table configurations. Referring to FIG. 1 1 , for example, the system 10’ is shown implemented with an alternate height-adjustable work table 12’. The work table 12’ is identical in many respects to the work table 12 illustrated in FIGS. 1 A-1 D, and like numbers are therefore used to identify like components.

The work table 12’ differs from the work table 12 primarily in the design of the support frame 16’ in which the elongated axial support member 20 and each height- adjustable column member 22A, 22B is coupled to a respective transverse table support member 28A’, 28B’ rearward of each member 28A’, 28B’. In this

embodiment, the elongated axial support member 20 is thus axially offset under the work top 14.

[0084] The embodiment illustrated in FIG. 1 1 also differs from that illustrated in FIGS. 1 A-1 D in that the embodiments 10’ illustrated in FIG. 1 1 includes three object detection sensor assemblies 36A-36C, with two of the sensor assemblies 36A, 36B mounted to the lateral support member 28A’ forward of the motor box 30A and spaced apart from one another and with the remaining sensor assembly 36C mounted to the lateral support member 28B’ forward of the motor box 30B. In alternate embodiments, more or fewer sensor assemblies may be mounted to either or both of the support members 28A’, 28B’ and/or to the underside of the work top 14. It will be understood that other configurations of the height-adjustable work table are contemplated, and that all such other configurations are intended to fall within the scope of this disclosure. It will be further understood that in any such alternate height-adjustable work table configuration, the system 10, 10’ may include any number of object detection sensor assemblies suitably mounted to the support frame and/or to the work top thereof.

[0085] In the embodiments of the system 10, 10’ illustrated in FIGS. 1 -1 1 , one example object detection sensor assembly embodiment is shown and described. Those skilled in the art will recognize, however, that the system 10, 10’ may alternatively be implemented using one or more other conventional object detection sensors, sensor assemblies and/or sensor systems, and it will be understood that all such alternate object detection sensors, sensor assemblies and/or sensing systems fall within the scope of this disclosure. As one example, one or more (or all) of the object detection sensor assemblies 36A-36D illustrated in the attached figures may alternatively be or include one or more conventional cameras, and in such embodiments the processing device 140 and/or the processing device 160 may be programmed to process, in a conventional manner, images or video segments produced by the one or more cameras to determine whether and when to deactivate or disable downward motion of the work top 14 to avoid contact between the underside 14B of the work top and an object positioned thereunder. As another example, whereas the embodiment 10 illustrated in FIGS. 1A-1 D places each of the sensor assembly pairs 36A, 36C and 36B, 36D directly across from one another along paths that are generally parallel with the front and rear edges 14C, 14D of the work top 14, alternate embodiments are contemplated in which any or all of the sensor assembly pairs are offset from one another, i.e., non-parallel with the front and/or rear edges 14C, 14D.

[0086] Another example alternate embodiment of the system 10, 10’ is illustrated in FIG. 12 in which the system 10” is implemented with a matrix of radiation transmission/detection sources mounted to and at least partially spanning the underside 14B of the work top 14. In the illustrated example, a matrix of fifteen side-by-side, transversely-extending rows of seven spaced-apart radiation

transmission/detection sources 300i,i - 300i5,7 are shown mounted to the underside 14B of the work top 14 and oriented such that the radiation transmitters each emit radiation perpendicularly away from the underside 14B of the work top 14 toward the support surface 26, e.g., floor (see, e.g., FIG. 1A). In alternate embodiments, the matrix of radiation transmission/detection sources may include more or fewer sources. In alternate embodiments, one or more of the sources 300i,i - 300i5,7 may be oriented such that the radiation emitted thereby is non-perpendicular relative to the underside 14B of the work top 14. In any case, each radiation

transmission/detection source may be configured to transmit and detect radiation in any frequency range and at any angle (i.e., any angle of beam spreading), and each source is illustratively operable as described above with respect to the object detection sensor assemblies 36A-36D to detect objects within a sensing range thereof.

[0087] Yet another example alternate embodiment of the system 10, 10’ is illustrated in FIG. 13 in which the system 10”’ is implemented in the form of a plurality of spaced-apart radiation transmitters 400i - 400N mounted to the underside 14B of the work top 14 and extending transversely at least partially along the width of the work top 14, and a corresponding plurality of spaced-apart radiation receivers or detectors 402i - 402N also mounted to the underside 14B of the work top 14 and extending transversely at least partially along the width of the work top opposite the radiation transmitters 400i - 400N, where N may be any positive integer. In this embodiment, each detector 402i- 402N is aligned with a corresponding transmitter 400i - 400N, and the transmitters 400i - 400N and detectors 402i - 402N are oriented such that radiation emitted by each transmitter 400i - 400N extends parallel to and below the underside 14B of the work top 14 to a corresponding one of the radiation detectors 402i - 402N. The transmitters 40CH - 400N are continuously or periodically activated so as to create a planar curtain of radiation transmission lines extending under the work top 14 which collectively defines a planar sensing range along and spaced apart from the underside 14B of the work top 14. Each radiation transmitter 400i - 400N and detector 402i - 402N are may be configured to transmit and detect radiation in any frequency range. In operation, an object is detected when it blocks reception by at least one of the detectors 402i - 402N of radiation transmitted by a corresponding one of the transmitters 400i - 400N. , i.e., such that an object detection signal for any transmitter/detector pair is defined by an absence of reception by the respective detector of the radiation emitted by the respective transmitter, having been blocked from reception by the object. In alternate embodiments, any or all of the transmitter/detector pairs may be offset from one another, i.e., to form one or more crisscross patterns of radiation across the underside 14B of the work top 14.

[0088] Those skilled in the art will recognize other conventional object detection sensors, sensor assemblies and/or sensing systems which may be implemented in any of the systems 10, 10’, 10”, 10’” illustrated in the attached drawings and described herein, and it will be understood that an such other conventional object detection sensors, sensor assemblies and/or sensing systems are intended to fall within the scope of this disclosure. It will be further understood that any of the embodiments illustrated in the attached drawings and described herein may be configured, e.g., by suitable mounting of the one or more sensor assemblies to the work table 12 and/or work top 14, by suitable selection of the angle of beam spreading of the emitted radiation about its central longitudinal axis, by suitable selection/control of the sensing range SR thereof and the like, to establish a radiation envelop (e.g., planar, linear, non-planar, non-linear, piecewise planar, piecewise linear and/or any combination thereof) and/or one or more radiation paths relative to the underside 14B of the work top 14 which provides for object detection at any desired distance from the underside 14B of the work top 14, at any desired distance from any frame component(s) secured to or extending along the underside 14B of the work top 14 and/or at any desired distance from any particular portion(s) of the underside 14B of the work top 14 and/or any such frame component(s). Any such alternate configuration would be a mechanical step for a skilled artisan in view of the concepts illustrated in the attached figures and described herein. It will be further understood that while in the various embodiments illustrated in the attached drawings emitted and detected radiation is described with respect to various example radiation frequencies and/ or frequency ranges, those skilled in the art will recognize that in one or more embodiments one or more of the sensor assemblies may be configured to emit/detect radiation at other frequencies and/or in other frequency ranges including, but not limited to, ultrasonic, ultraviolet, visible, infrared and/or radar frequencies and/or frequency ranges.

[0089] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications consistent with the disclosure and recited claims are desired to be protected. For example, the system 10 has been illustrated and described herein as being configured and operable to prevent contact between the underside 14B of the work top 14 of the table 12 and an object disposed under the work top 14. It will be understood that this configuration is illustrated and described only by way of example, and that other embodiments are contemplated in which the system 10 is alternatively configured or optimized to prevent contact between the lateral or transverse table support members 28A, 28B of the frame 16 and an object disposed thereunder, and/or to prevent contact between the elongated axial support member 20 (e.g., including either or both of the elongated axial support members 20A, 20B) of the frame 16 and an object disposed thereunder. Still other embodiments of the system 10 are contemplated in which one or more object detection sensors are positioned at, along or above the top surface 14A of the work top 14, and in such embodiments the system 10 may be alternatively or additionally configured to prevent contact between the top surface 14A of the work top 14 and an object disposed thereabove.