TECHNICAL FIELD

[0001] The present invention generally relates to electrical switches, and more particularly relates to an electrical switch system and assembly that is relatively compact, inexpensive, and exhibits a positive opening function.

BACKGROUND

[0002] Electrical switches are used in myriad systems and environments, and are used to implement numerous and varied switch-related functions. In many instances, switches are used to sense the position of one or more components. For example, a switch may be configured to change states from an open position to a closed position, or vice-versa, when one or more components attain a particular relative or absolute position. One example of a system that uses electrical switches is an elevator system. In particular, an elevator system may include one or more electrical switches to indicate when the elevator doors are open and/or closed.

[0003] Some presently known electrical switches that are used to indicate, for example, the relative positions of elevator doors, are generally safe, reliable, and robust, but do suffer certain drawbacks. For example, some of the presently known switches exhibit a relatively low international protection grade, exhibit deleterious effects when subject to operational vibration, and develop oxidized contacts.

[0004] Hence, there is a need for an electrical switch that exhibits a relatively high international protection grade, can withstand operational vibrations, and is less prone to contact oxidation. The present invention addresses one or more of these needs. BRIEF SUMMARY

[0005] In one embodiment, an electrical switch assembly includes a housing, first and secondary stationary contacts, and a switch mechanism. The first and second stationary contacts are mounted within the housing and are spaced apart from each other. The switch mechanism is movably mounted within the housing and comprises a first movable contact and a second movable contact. The switch mechanism is movable between a closed position and an open position. In the closed position, the first and second movable contacts are electrically connected to the first and second stationary contacts, respectively, and in the open position, the first and second movable contacts are electrically disconnected from the first and second stationary contacts, respectively. The switch mechanism further includes a main shaft, an operational cam, a first contact frame, and a second contact frame. The main shaft has a first end and a second end. The operational cam is coupled to the main shaft between the first and second ends, is adapted to receive an input force in one of a first direction or a second direction, and is configured, in response thereto, to rotate the main shaft in one of a first rotational direction or a second rotational direction, respectively. The first contact frame is coupled to the first movable contact and is further coupled the first end of the main shaft. The first contact frame is responsive to rotation of the main shaft in the first rotational direction or the second rotational direction to translate in a first translational direction or a second translational direction, respectively, to thereby move the first movable contact toward the first stationary contact or away from the first stationary contact, respectively. The second contact frame is coupled to the second movable contact and is further coupled to the second end of the main shaft. The second contact frame is responsive to rotation of the main shaft in the first rotational direction or the second rotational direction to translate in the first translational direction or the second translational direction, respectively, to thereby move the second movable contact toward the second stationary contact or away from the second stationary contact, respectively.

[0006] In another embodiment, an electrical switch system includes a key, a housing, first and second stationary contacts, and a switch mechanism. The housing has a key slot into which the key may be inserted, and from which the key may be subsequently removed.

The first and second stationary contacts are mounted within the housing and are spaced apart from each other. The switch mechanism is movably mounted within the housing and comprises a first movable contact and a second movable contact. The switch mechanism is movable between a closed position and an open position. In the closed position, the first and second movable contacts are electrically connected to the first and second stationary contacts, respectively, and in the open position, the first and second movable contacts are electrically disconnected from the first and second stationary contacts, respectively. The switch mechanism further comprises a main shaft an operational cam, a first contact frame, and a second contact frame. The main shaft has a first end and a second end. The operational cam is coupled to the main shaft between the first and second ends. The operational cam is configured to be engaged by the key when it is inserted into the key slot, and is further configured to rotate the main shaft in a first rotational direction while the key is being inserted into the key slot and to rotate the main shaft in a second rotational direction while the key is being subsequently removed from the key slot. The first contact frame is coupled to the first movable contact and is further coupled the first end of the main shaft. The first contact frame is responsive to rotation of the main shaft in the first rotational direction and the second rotational direction to translate in a first translational direction and second translational direction, respectively, to thereby move the first movable contact toward the first stationary contact and away from the first stationary contact, respectively. The second contact frame is coupled to the second movable contact and is further coupled to the second end of the main shaft. The second contact frame is responsive to rotation of the main shaft in the first rotational direction and the second rotational direction to translate in the first translational direction and the second translational direction, respectively, to thereby move the second movable contact toward the second stationary contact and away from the second stationary contact, respectively.

[0007] In yet another embodiment, an electrical switch assembly includes a housing, first and second stationary contacts, and a switch mechanism. The first and second stationary contacts are mounted within the housing and are spaced apart from each other. The switch mechanism is movably mounted within the housing and comprises a main shaft, an operational cam, a first contact frame, a first movable contact, a second contact frame, a second moveable contact, a first rotary bar, and a second rotary bar. The main shaft having a first end and a second end. The operational cam is coupled to the main shaft between the first and second ends. The operational cam is adapted to receive an input force in one of a first direction or a second direction and is configured, in response thereto, to rotate the main shaft in one of a first rotational direction or a second rotational direction, respectively. The first contact frame is coupled the first end of the main shaft, and is responsive to rotation of the main shaft in the first rotational direction or the second rotational direction to translate in a first translational direction or a second translational direction, respectively. The first movable contact is coupled to and extends from the first contact frame. The first movable contact moves toward the first stationary contact when the first contact frame moves in the first translational direction, and moves away from the first stationary contact when the first contact frame moves in the second translational direction. The second contact frame is coupled the second end of the main shaft, and is responsive to rotation of the main shaft in the first rotational direction or the second rotational direction to translate in the first translational direction or the second translational direction, respectively. The second movable contact coupled to and extending from the second contact frame, the second movable contact moves toward the second stationary contact when the second contact frame moves in the first translational direction, and moves away from the second stationary contact when the second contact frame moves in the second translational direction. The first rotary bar is rotationally coupled between the first end of the main shaft and the first contact frame. The first rotary bar is configured, upon rotation of the main shaft in the first rotational direction or the second rotational direction, to supply a first translational force to the first contact frame in the first translational direction or the second translational direction, respectively. The second rotary bar is rotationally coupled between the second end of the main shaft and the second contact frame. The second rotary bar is configured, upon rotation of the main shaft in the first rotational direction or the second rotational direction, to supply a second translational force to the second contact frame in the first translational direction or the second translational direction, respectively.

[0008] Furthermore, other desirable features and characteristics of the electrical switch system and electrical switch assembly will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

[0010] FIG. 1 depicts an isometric view of an electrical switch system according to one embodiment; [0011] FIGS. 2 and 3 depict partially transparent isometric views of the electrical switch system of FIG. 1, with the electrical switch assembly in the closed position and the open position, respectively;

[0012] FIG. 4 depicts an isometric view of an embodiment of a switch mechanism that may be used to implement the electrical switch assembly depicted in FIGS. 1-3;

[0013] FIG. 5 depicts an end view of the electrical switch system with the cover removed from the housing of the electrical switch assembly;

[0014] FIG. 6 depicts an isometric exploded view of the electrical switch system depicted in FIG. 1 ;

[0015] FIG. 7 depicts an isometric view of a contact frame that may be used to implement the switch mechanism depicted in FIG. 2; and

[0016] FIG. 8 depicts a side view of a contact holder with contacts coupled thereto that may be used to implement the switch mechanism depicted in FIG. 2.

DETAILED DESCRIPTION

[0017] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Thus, any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description.

[0018] Referring first to FIG. 1, an isometric view of an electrical switch system 100 is depicted, and includes a key 102 and an electrical switch assembly 104. The key 102 may be variously configured, but in the depicted embodiment it includes a mount flange 106 and a switch operator 108. The mount flange 106 is configured to be mounted on, or otherwise coupled to, a movable component. To facilitate this, the mount flange 106 includes a plurality of fastener openings 1 12. A non-depicted fastener, such as a screw or other suitable device, may be inserted through each fastener opening 1 12 and into the component to which the key 102 is being mounted.

[0019] The switch operator 108 extends from the mount flange 106 and, as will be described further below, is selectively inserted into, and subsequently removed from, the electrical switch assembly 104. Although the switch operator 108 may be variously configured, in the depicted embodiment it includes a base section 1 14, a pair of arms 1 16 (1 16-1, 116-2), and a cross member 1 18. The base section 1 14 is connected to, and extends from, the mount flange 106. The arms 1 16 extend from the base section 1 14 and are separated from each other by a distance (d) to form a space 122 between the arms 1 16. The cross member 1 18 is connected to and extends perpendicularly from each arm 1 16 and across the space 122.

[0020] With reference now to FIGS. 1 , 2, and 3, it may be seen that the electrical switch assembly 104 includes a housing 124, within which a plurality of stationary contacts 126 and a switch mechanism 128 are mounted and enclosed via a gasket 602 and cover 604 (see FIG. 6). The housing 124 includes a key insertion slot 132 and an alternate opening 133. The key insertion slot 132, as this nomenclature denotes, is configured to allow the key 102 to be inserted into, and subsequently removed from, the housing 124. As will be described momentarily, when the key 102 is inserted into housing 124 via the key slot 132, the electrical switch assembly 104 changes from one state to another state, and when the key 102 is subsequently removed from the housing 124, the electrical switch assembly 104 changes back to its original state. The alternate opening 133 provides an alternate means to access and operate the switch mechanism 128, if needed or desired. It also provides a means by which the position of the switch mechanism 128 may be viewed.

[0021] The stationary contacts 126 are mounted within the housing 124 and are spaced apart from each other. In the depicted embodiment, the electrical switch assembly 104 includes four stationary contacts - first, second, third, and fourth stationary contacts 126-1, 126-2, 126-3, 126-4. It will be appreciated, however, that in other embodiments, the electrical switch assembly 104 could be implemented with only two stationary contacts (e.g., 126-1 and 126-2), or with more than four stationary contacts, if needed or desired. The stationary contacts 126 are individually coupled, as shown in FIG. 6, to output terminals 606 via fastener hardware 608. Two of the output terminals 606 are mounted on a first cover plate 612- 1 and two other output terminals 606 are mounted on a second cover plate 612-2.

[0022] The switch mechanism 128 is movably mounted within the housing 124 and has a plurality of movable contacts 134 coupled thereto. In the depicted embodiment, the switch mechanism 128 includes four movable contacts - first, second, third, and fourth movable contacts 134-1 , 134-2, 134-3, 134-4 - each associated with a different one of the stationary contacts 126. As with the stationary contacts 126, it will be appreciated that in other embodiments, the switch mechanism 128 could be implemented with only two movable contacts (e.g., 134-1 and 134-2), or with more than four movable contacts, if needed or desired. In the depicted embodiment, the first movable contact 134-1 is coupled to, spaced apart from, and movable with, the third movable contact 134-3, and thus forms a first pair of movable contacts. Similarly, the second movable contact 134-2 is coupled to, spaced apart from, and movable with, the fourth movable contact 134-4 and thus forms a second pair of movable contacts. More specifically, and with quick reference to FIG. 8, it is seen that each pair of movable contacts 134-1, 134-3 (134-2, 134-4) are coupled together via a contact carrier 802.

[0023] No matter the specific number of movable contacts 134, the switch mechanism 128 is movable between a closed position, which is the position depicted in FIG. 2, and an open position, which is the position depicted in FIG. 3. In the closed position, each movable contact 134 is electrically connected to its associated stationary contact 126. Conversely, in the open position, each movable contact 134 is electrically disconnected from its associated stationary contact 126. Referring now to FIGS. 4-6, a particular configuration of the switch mechanism 128 that implements this functionality will be described.

[0024] The depicted switch mechanism 128 includes a main shaft 402, an operational cam 404, a first contact frame 406, and a second contact frame 408. The main shaft 402 includes a first end 412 and a second end 414 and, as FIGS. 5 and 6 depict, is rotationally mounted on a shaft mount 502 that is formed within the housing 124. The shaft mount 502, as depicted in FIG. 6, includes a pair of openings 614 (only one visible in FIG. 6) through which the main shaft 402 extends. As FIG. 6 additionally depicts, a pair of axles 616 (only one visible) extend, one each, from the first end 412 and second end 414 of the main shaft 402. The purpose of the axles 616 is discussed further below. Referring once again to FIG. 4, it is seen that a first seal ring 416-1 and a second seal ring 416-2 are mounted on opposing portions of the main shaft 402. When the main shaft 402 is mounted on the shaft mount 502, the seal rings 416 frictionally engage the shaft mount 502, and more specifically the surfaces of the shaft mount 502 that define the openings 614. Because the seal rings 416 frictionally engage the shaft mount 502, a positive force is required to move the switch mechanism 128 between its open and closed positions.

[0025] With continued reference to FIG. 4, the operational cam 404 is coupled to the main shaft 402 between the first and second ends 412, 414, and is configured to be engaged by the key 102 when the key 102 is inserted into the key slot 132. The operational cam 404 is additionally configured to rotate the main shaft 402 in a first rotational direction 418 while the key 102 is being inserted into the key slot 132, and to rotate the main shaft 402 in a second rotational direction 422 while the key 102 is being subsequently removed from the key slot 132. The operational cam 404 may be variously configured, but in the depicted embodiment it includes a shaft mount portion 424 and two key engagement arms 426 (426-1 , 426-2). The shaft mount portion 424 is mounted on the main shaft 402, and the key engagement arms 426 extend radially outwardly from the shaft mount portion 424 in a substantially V-shaped manner to form a slot 425 for receiving the key 102.

[0026] As may be readily appreciated, when the key 102 is initially inserted into the key slot 132, the cross member 1 18 is disposed between the key engagement arms 426. As the key 102 is inserted further into the key slot 132, the cross member 1 18 engages one of the key engagement arms 426-1, and supplies a force thereto that rotates the main shaft 402 in the first rotational direction 418. As depicted in FIG. 2, the other key engagement arm 426- 2 extends through the space 122 between the key's two arms 1 16. When the key 102 is subsequently removed from the key slot 132, the cross member 1 18 engages the other key engagement arm 426-2, and supplies a force thereto that rotates the main shaft 402 in the second rotational direction 422.

[0027] Returning once again to FIG. 4, the first contact frame 406 is coupled to the first end 412 of the main shaft 402, and the second contact frame 408 is coupled to the second end 414 of the main shaft 402. The first and second contact frames 406, 408 are both responsive to rotation of the main shaft 402 in the first rotational direction 418 and the second rotational direction 422 to translate in a first translational direction 428 and a second translational direction 432, respectively. In addition to being coupled to the main shaft 402, the first contact frame 406 is coupled to the first and third movable contacts 134-1, 134-3, and the second contact frame 408 is coupled to the second and fourth movable contacts 134- 2, 134-4. Thus, when the first and second contact frames 406, 408 are translated in the first translational direction 428, each of the movable contacts 134 is moved toward its associated stationary contact 126, and when the first and second contact frames 406, 408 are translated in the second translational direction 432, each of the movable contacts 134 is moved away from its associated stationary contact 126.

[0028] Although the first and second contact frames 406, 408 may be coupled to the main shaft 402 using any one of numerous devices and techniques, in the depicted embodiment each is coupled to the main shaft 402 via a rotary bar. In particular, a first rotary bar 434-1 is rotationally coupled between the first end 412 of the main shaft 402 and the first contact frame 406, and a second rotary bar 434-2 is rotationally coupled between the second end 414 of the main shaft 402 and the second contact frame 408. As shown more clearly in FIG. 6, the rotary bars 434 each have a first opening 618 and a second opening 622, which are formed in the opposing two ends of the rotary bars 434. The rotary bars 434 are each rotationally mounted on the axles 616 that extend from the first and second ends 412, 414 of the main shaft 402 via the first openings 618. The rotary bars 434 are also rotationally mounted on separate frame shafts 624 via the second openings 622. The frame shafts 624 are rotationally mounted, one each, to the first and second contact frames 406, 408. With this configuration, when the main shaft 402 is rotated in the first rotational direction 418 or the rotational second direction 422, the first rotary bar 434-1 will supply a translational force to the first contact frame 406 in the first translational direction 428 or the second translational direction 432, respectively, and the second rotary bar 434-2 will supply a second translational force to the second contact frame 408 in the first translational direction 428 or the second translational direction 432, respectively.

[0029] With reference now to FIG. 7, a description of the first and second contact frames 406, 408 will be provided. Because each is identically constructed, a description of only one contact frame will be provided. The contact frame 406 (408) includes a rotary bar connection section 702 and a movable contact section 704. The rotary bar connection section 702 includes an outer surface 706 that defines a first guide bar 708-1 and a second guide bar 708-2. The first and second guide bars 708-1, 708-2 are disposed within corresponding guide slots 504 (see FIG. 5, where only two are shown) formed on an inner surface of the housing 124. The rotary bar connection section 702 additionally includes a frame shaft opening 712 (depicted in phantom in FIG. 7) that receives one of the frame shafts 612.

[0030] The movable contact section 704 is coupled to the rotary bar connection section 702 and includes an outer surface 714 that defines a third guide bar (not visible in FIG. 7) and a fourth guide bar 708-4, and an inner surface 716 that defines a cavity 718. As with the first and second guide bars 708-1 , 708-2, the third and fourth guide bars 708-3, 708-4 are disposed within corresponding guide slots (not visible) formed on an inner surface of the housing 124. The contact carrier 802 that couples the two movable contacts 134 together is movably disposed within, and extends from, the cavity 718. The contact carrier 802 is disposed such that the movable contacts 134 are disposed outside of the cavity 718 and, as will be discussed below, may be moved relative to the movable contact section 704.

[0031] A movable contact holder 722 and a retainer spring 724 are also disposed within the cavity 718. The movable contact holder 722 engages the movable contacts 134, and the retainer spring 724 engages the inner surface 716 at one end and the movable contact holder 722 at the other. The retainer spring 724 is configured to supply a bias force to the movable contact holder 722 that urges the movable contact holder 722 into engagement with the contact carrier 802.

[0032] Referring back to FIG. 5, two additional springs are included in the electrical switch assembly 104. A first bias spring 506-1 is disposed between the housing 124 and a blind opening formed in the first contact frame 406, and a second bias spring 506-2 is disposed between the housing 124 and a blind opening the second contact frame 408. The first and second bias springs 506-1 , 506-2 supply a bias force to the first and second contact frames 406, 408, respectively, in the second translational direction 432.

[0033] Having described the electrical switch system 100 from a structural standpoint, and having generally described the functions of various components that make up the electrical switch system 100, the overall operation of the depicted electrical switch system 100 will now be provided. Before doing so, however, it is noted that the electrical switch assembly 104 was described above as being configured with normally-open (NO) contacts. That is, when the key 102 is removed, the fixed contacts 126 and movable contacts 134 are electrically disconnected from each other. It will be appreciated that in alternative embodiments, one or more of the contacts could be configured as normally-closed (NC) contacts.

[0034] Initially, it is assumed that the electrical switch system 100 is in the state depicted in FIGS. 1, 3, and 5, with the key 102 disposed away from the electrical switch assembly 104. In this state, the switch mechanism 128 is in the open position, which means the operational cam 404 is in its first end position, and each movable contact 134 is electrically disconnected from its associated stationary contact 126. Thereafter, if a force is supplied to the key 102 to move it into the key slot 132, the cross member 1 18 will engage one of the key engagement arms 426-1 and supply a force to the operational cam 404 that causes it to rotate the main shaft 402 in the first rotational direction 418. In response to the main shaft 402 rotating in the first rotational direction 418, the first and second rotary bars 434 supply a translational force to the first and second contact frames 406, 408, respectively, in the first translational direction 428. Thus, the movable contacts 134 begin moving in the first translational direction 428 toward the stationary contacts 126.

[0035] Before the key 102 is fully inserted, and before the operational cam 404 is moved to its second end position (see FIG. 2), the switch mechanism 128 is configured such that the movable contacts 134 engage, and are thus electrically connected to, the stationary contacts 126. Further insertion of the key 102 will result in further rotation of the main shaft 402 in the first rotational direction 418, and further translation of the first and second contact frames 406, 408 in the first translational direction 428. However, the contact carriers 802 (and thus the movable contacts 134) will not further translate. Rather, the contact carriers 802 will slide within the cavities 718, as the first and second contact frames 406, 408 continue to translate. When the key 102 is fully inserted and the operational cam 404 is at its second end position, the first and second bias springs 506-1 , 506-2 will be fully enveloped by the first and second contact frames 406, 408, respectively.

[0036] If a force is then supplied to the key 102 to move it in the second translational direction 432, the cross member 1 18 will engage the other key engagement arm 426-2, and supply a force to the operational cam 404 that causes it move out of its second end position, and rotate the main shaft 402 in the second rotational direction 422. In response to the main shaft 402 rotating in the second rotational direction 422, the first and second rotary bars 434 supply a translational force to the first and second contact frames 406, 408, respectively, in the second translational direction 432. Thus, the first and second contact frames 406, 408 will begin moving in the second translational direction 432.

[0037] It is noted that the contact carriers 802 will initially slide within the cavities 718 when the first and second contact frames 406, 408 begin to translate in the second translational direction 432. Thus, the movable contacts 134 will remain electrically connected to the stationary contacts 126 until the first and second contact frames 406, 408 translate to a position where the contact carriers 802 no longer slide in the cavities 718. At that point, the movable contacts 134 will disengage, and thus be electrically disconnected from, the stationary contacts 126. As the key 102 continues to be retracted from the key slot 132, the operational cam 404 will continue to rotate the main shaft in the second rotational direction 422, and thus the first and second contact frames 406, 408 will continue to translate in the second translational direction 432. That is, until the operational cam 404 is moved into its first end position (see FIG. 3).

[0038] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.