[0001 ] Doors can function as movable barriers over an opening to control access to an enclosure, for example to access internal components. Doors may be manually operated or be motor driven.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIGS. 1 A and 1 B are perspective views of a pair of doors to an enclosure in open and closing configurations, respectively.

[0003] FIG. 2 is a schematic diagram showing features of an example device.

[0004] FIG. 3 is a flowchart of an example method that uses the example device.

[0005] FIG. 4 is a schematic representation of example operation of the device when an obstacle is located in the path of the doors.

[0006] FIG. 5 is a schematic representation of another example operation of the device when an obstacle is located in the path of the doors.

[0007] FIG. 6 is a schematic representation of another example operation of the device when an obstacle is located in the path of the doors.

[0008] FIG. 7 is a schematic representation of another example operation of the device when no obstacle is located in the path of the doors.

DETAILED DESCRIPTION [0009] Motor-driven doors are capable of closing on obstacles, such as human fingers, in the opening between the doors. Sensors can be used to detect such obstacles in the path of closing doors. One such sensor comprises a light beam aimed across the opening such that when the beam is broken by an obstacle, the motor is prevented from closing the door. Infrared and radar safety sensors may also be used. Other sensors such as resistance-sensing motors can be used to reverse the closing action of a door after an obstacle has been encountered, or pressure sensors can be used to detect an air pressure difference within a rubber bumper on the edge of the door when the door closes on an obstacle. Such sensors can be complex, expensive and occupy considerable space within the enclosure.

[0010] In order to prevent motor-driven doors from closing on an obstacle, a device is set forth herein that uses sensors, a controller and a timer for causing the motor to open the doors in the event of such an obstacle in the path of the closing doors. The device is simple, inexpensive and occupies a small amount of space within the enclosure.

[0011] Sensors may be placed in the path of travel of each of a pair of doors, wherein the sensors are placed asymmetrically relative to the center of an opening between the doors. If at least one of the sensors fails to detect a respective door passing the location of the sensor within a first time period, then the doors are opened to prevent closing on the obstacle. If both of the sensors detect their respective doors passing the locations of the sensors within a second time period that is greater than the first time period, then the doors are permitted to close.

[0012] In examples, the device can comprise a first door and a second door to access an opening; a motor connected to the first door and second door; a controller for causing the motor to selectively open and close the first door and second door; a timer; a first sensor on each of the first door and second door to detect movement of the first door and second door from an open configuration toward a closed configuration and in response cause the timer to start timing; a second sensor on each of the first door and second door to detect movement of the first door and second door to first and second positions, respectively, the first and second positions being asymmetrical relative to the center of the opening; wherein the controller causes the motor to open the first door and second door after the timer counts more than a first time period in the absence of at least one second sensor indicating that at least one of the first door and second door has moved to the first or second positions, respectively; and wherein the controller causes the motor to continue movement of the first door and second door from the open configuration toward the closed configuration until the timer counts more than a second time period greater than the first time period if the second sensor indicates that the first door and second door have moved to the first and second positions, respectively.

[0013] In other examples, a method can comprise detecting via a first sensor on each of a first door and a second door movement of the first door and second door from an open configuration toward a closed configuration and in response causing a timer to start timing; detecting via a second sensor on each of the first door and second door movement of the first door and second door to first and second positions, respectively, the first and second positions being asymmetrical relative to the center of an opening between the first door and second door; causing the first door and second door to open after the timer counts more than a first time period in the absence of at least one second sensor indicating that at least one of the first door and second door has moved to the first or second positions, respectively; and causing the first door and second door to continue movement from the open configuration toward the closed configuration until the timer counts more than a second time period greater than the first time period if the second sensor indicates that the first door and second door have moved to the first and second positions, respectively

[0014] In other examples, a device can comprise a controller for causing a motor to selectively open and close a first door and a second door to access an opening; a timer; a first sensor on each of the first door and second door for actuating in response to movement of the first door and second door from an open configuration toward a closed configuration; and a second sensor on each of the first door and second door for actuating in response to movement of the first door and second door to first and second positions, respectively, the first and second positions being asymmetrical relative to the center of the opening; wherein the controller causes the timer to start timing in response to actuation of the first sensor; wherein the controller causes the motor to continue movement of the first door and second door from the open configuration toward the closed configuration until the timer counts more than a second time period greater than the first time period and the second sensor on each of the first door and second door is actuated.

[0015] The controller can include the timer.

[0016] The motor can close the first door and second door at a velocity equal to the dimension of the opening divided by the second time period.

[0017] The first position can be offset from the center of the opening by less than the second position is offset from the center of the opening whereby the controller causes the first door and second door to open if movement of the first door to the first position is detected before movement of the second door to the second position.

[0018] The dimension of the opening can be approximately 40mm, the velocity can be approximately 2mm/sec, the first time period can be approximately 8.5 sec and the second time period can be approximately 10 sec.

[0019] The first position can be approximately 4cm from the center of the opening and the second position can be approximately 6cm from the center of the opening.

[0020] FIGS. 1 A and 1 B are perspective views of a pair of doors 110 and 115 to an enclosure 100 in open and closing configurations, respectively. In FIG. 1 A, the pair of doors 110 and 115 are in an open configuration for access to the enclosure 100, for example to access internal components such as a camera 120. In some examples, internal components may include other devices such as microphones, audio output devices such as speakers, or other types of devices. In FIG. 1 B, the doors 110 and 115 are in a closing configuration (i.e., moving from an open configuration to a closed configuration), as shown by solid line arrows, while encountering an obstacle 130, such as a human finger, in the path of the closing doors.

[0021 ] In order to prevent motor-driven doors 110 and 115 from closing on obstacle 130, enclosure 100 includes a device 140 as set forth herein that uses sensors, a controller and a timer for causing the motor to open the doors in the event of such an obstacle in the path of the closing doors.

[0022] FIG. 2 is a schematic diagram showing features of an example device. The device can comprise a controller 200 for causing motors 210A and 210B to selectively open and close first door 110 and second door 115 to access opening 215. Although two motors 210A and 210B are shown in the example, a single motor may be used with mechanical linkages to both doors 110 and 115. In an example, each motor 210A and 210B can be a stepper motor (also known as step motor or stepping motor), which is a brushless DC electric motor that divides a full rotation into a number of equal steps, where the step angle of a stepping motor refers to the mechanical angle corresponding to one step of the rotor. In examples, the controller 200 generates voltage pulses that cause the 210A and 210B to rotate one step per voltage pulse. For motors 210A and 210B with 18 degrees/step and respective lead screws providing a transmission ratio of 6:1 for driving movement of the doors 110 and 155, the step of each motor becomes 18/6=3 degrees/step. For a 400 pps (pulse per second motor), a single pulse from controller 200 results in the motors 210A or 210B rotating 3 degrees. Thus, one full 360-degree rotation of the motor requires 360/3=120 pulses from controller 200 (i.e. one full rotation in 120/400 = 0.3 seconds).

[0023] Doors 110 and 115 may be mounted on a ball rail 218 or other suitable translational components, e.g., wheels, tracks, pulleys, gear racks, etc. The controller 200 can include a timer 220. First sensors 230A and 230B are symmetrically positioned proximate outside edges of the first door 110 and second door 115, respectively, to detect movement of the first door 110 and second door 115 from an open configuration toward a closed configuration and in response cause the timer 220 to start timing. Second sensors 240A and 240B are positioned asymmetrically relative to inside edges of the first door 110 and second door 115, respectively, to detect movement of the first door 110 and second door 115 to first and second positions, respectively.

[0024] In examples, sensors 230A, 230B, 240A and 240B can be mechanical switches, for example low current detector switches. Alternatively, optical switches may be used, such as electronic reflective optical sensors.

[0025] The first door 110 and second door 115 include door detents 250A and 250B, respectively, near the outside door edges and further door detents and 270A and 270B, respectively, near the inside edges of doors 110 and 115. Sensors 230A and 230B include sensor detents 260A and 260B, respectively.

[0026] FIG. 3 is a flowchart of an example method that uses the example device. In operation, controller 200 causes motors 210A and 210B to move doors 110 and 115 from an open configuration toward a closed configuration, illustrated in FIG. 2, at a rate defined by the step angle and transmission ratio of motors 210A and 210B, such that at least one of door detents 250A and 250B moves past sensor detents 260A and 260B thereby actuating a corresponding one of the sensors 230A and 230B, respectively, at 300, for starting the timer 220 at 310. If controller 200 determines that sensor 240A has been actuated but sensor 240B has not been actuated (a YES at 315), which means door 110 has encountered an obstacle, such as obstacle 130, then, at 320, controller 200 causes the motors 210A and 210B to re-open doors 110 and 115 and resets the timer 220. Because doors 110 and 115 close at the same rate based on the step angle and transmission ratio for the motors 210A and 210B, the asymmetric positioning of sensors 240A and 240B will result in door 115 actuating sensor 240B before door 110 actuates sensor 240B in the absence of an obstacle. If, after a specified time period T1 (a YES at 330), neither of the asymmetrically positioned sensors 240A and 240B is actuated by either of door detents 270A and 270B passing corresponding sensor detents 280A and 280B (a NO at 340 and 345), then controller 200 causes the motors 210A and 210B to re-open doors 110 and 115 and resets the timer 220, at 320, thereby preventing the doors from continuing to close on an obstacle, such as obstacle 130. Likewise, if, after time period T1 (a YES at 330), sensor 240A is actuated but sensor 240B is not actuated (a NO at 340 and a YES at 345), then controller 200 causes the motors 210A and 210B to re-open doors 110 and 115 and resets the timer 220, at 320. If, after time period T1 (a YES at 330), sensor 240A is actuated but sensor 240B is not actuated (a YES at 340 and a NO at 350), then controller 200 causes the motors 210A and 210B to re-open doors 110 and 115 and resets the timer 220, at 320, thereby preventing the doors from continuing to close on an obstacle. However, if both sensors 240A and 240B are actuated, indicating that there is no obstacle in the path of the doors 110 and 115, the doors continue to close. Once the doors are fully closed, indicated by the passage of a second time period T2 related to the rate of closure of the doors (a YES at 360), then controller 200 resets the timer 220, at 370.

[0027] In an example, if the size of the obstacle 130 is 13mm (e.g., the approximate width of a human finger), the desired length of time for closing doors 110 and 115 is T2 = 10 seconds, and the distance W from each of sensor detents 260A and 260B to the center of the opening (i.e., where the inside edges of doors 110 and 155 contact when closed) is approximately 20mm, then if the distance X of sensor detent 280A to the center of the opening is approximately 4mm, and the distance Y of sensor detent 280B to the center of the opening is approximately 6mm, then the time for door 110 to actuate sensor 240A is 8 seconds (W- X = 16mm/2mm per second), so T1 > 8 seconds (e.g.

8.5 seconds), and operation of controller 200 to control motors 210A and 210B may be summarized as shown in Table A.

TABLE A

[0028] FIG. 4 is a schematic representation of example operation of the device 140 when an obstacle is located in the path of the doors 110 and 115.

[0029] FIG. 5 is a schematic representation of another example operation of the device 140 when an obstacle is located in the path of the doors 110 and 1 15.

[0030] FIG. 6 is a schematic representation of another example operation of the device 140 when an obstacle is located in the path of the doors 110 and 115. In FIG. 6, sensor 240B has been actuated while sensor 240A has not been actuated.

[0031 ] FIG. 7 is a schematic representation of another example operation of the device when no obstacle is located in the path of the doorsl 10 and 115. In FIG. 7, both sensor 240A and sensor 240B have been actuated.

[0032] Thus, with reference to TABLE A, if both sensor 240A and sensor 240B are actuated as a result of the doors 110 and 115 closing, then after 10 seconds, (i.e. the time for the doors to close completely at a rate of 20mm/10sec=2 mm/seconds), as shown in FIG. 7, controller 200 resets the timer 220. Since the sensors 240 and 240B are positioned asymmetrically, such that sensor 240B is closer to detent 270B than sensor 240B is to detent 270A, if sensor 240A is actuated before sensor 240B then movement of doors 110 and 115 is halted and the doors are caused to reopen (i.e., there is an obstacle 13mm or greater in the path of the doors), as shown in FIG. 5. If sensor 240A is not activated within 8.5 seconds, whether or not sensor 240B is actuated, then movement of doors 110 and 115 is halted and the doors are caused to reopen, as shown in FIG. 6. If neither sensor 240A nor sensor 240B is actuated within 8.5 seconds, then movement of doors 110 and 115 is halted and the doors are caused to reopen (i.e., there is an obstacle 13mm or greater in the path of the doors), as shown in FIG. 4. Likewise, if sensor 240A is actuated but sensor 240B is not actuated within 8.5 seconds, then movement of doors 110 and 115 is halted and the doors are caused to reopen, as shown in FIG. 6.

[0033] As set forth herein, a device and method may be provided that uses inexpensive sensors and a timer for preventing motor-driven doors from closing on an obstacle, such as a human finger.

[0034] It should be recognized that features and aspects of the various examples provided above can be combined into further examples that also fall within the scope of the present disclosure. In addition, the figures are not to scale and may have size and shape exaggerated for illustrative purposes.