WO2017024545A1

WO2017024545A1 - Limit switch with integrated reset key

Info

Publication number: WO2017024545A1
Application number: PCT/CN2015/086735
Authority: WO
Inventors: Xingjun OU; Rufus WEI; Keyong ZHOU; Dongmei DENG
Original assignee: Honeywell International Inc.
Priority date: 2015-08-12
Filing date: 2015-08-12
Publication date: 2017-02-16
Also published as: CN108292569B; CN108292569A

Abstract

A reset key assembly (104) for a limit switch (206) includes a switch head (214), a reset key opening (216), and a reset key (218). The switch head (214) is adapted to be coupled to a limit switch (206), and has an inner surface (222) and an outer surface (224). The inner surface (222) defines a limit switch cavity (226) that is dimensioned to have a portion of a limit switch (206) movably disposed therein. The outer surface (224) has a reset key groove (228) formed therein. The reset key opening (216) is formed in the switch head (214) and extends between the inner surface (222) and a portion of the reset key groove (228). The reset key (218) is disposed within the reset key groove (228) and extends at least partially into the reset key opening (216). The reset key (218) is movable, relative to the switch head (214), between a switch unlock position and a switch lock position.

Description

LIMIT SWITCH WITH INTEGRATED RESET KEY

TECHNICAL FIELD

The present invention generally relates to resettable limit switches, and more particularly relates to a limit switch with an integrated reset key.

BACKGROUND

Various types of switches are used in numerous and varied systems to implement numerous and varied switching functions. One particular type of switch is a limit switch and may be used, for example, to sense when an object contacts or passes by the switch (or vice-versa) . A typical limit switch is an electromechanical device that consists of an actuator mechanically coupled to switching device that is movable from a first position to a second position to either make or break an electrical connection. When an object comes into contact with the actuator, the actuator moves the switching device from the first to the second position. In some implementations, when the switching device is moved to the second position, it is mechanically locked into that position unless or until it is released via a reset key.

Currently, most limit switch reset keys are disposed either separate from the limit switch itself or extend from the limit switch. Because of this, inadvertent operation of the reset key can undesirably occur. Moreover, many limit switch reset keys are formed separately from the limit switch, which increases overall part quantity and costs associated with the limit switch assembly. Additionally, the configurations of the limit switches and associated limit switch reset keys limit where and how the limit switches can be mounted.

Hence, there is a need for limit switch and limit switch reset key that significantly reduces the likelihood of (or even eliminates) inadvertent operations and/or reduces overall part quantity and costs associated with the limit switch assembly and/or does not limit where and how the limit switch can be mounted. The present invention addresses at least this need.

BRIEF SUMMARY

This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In one embodiment, a reset key assembly for a limit switch includes a switch head, a reset key opening, and a reset key. The switch head is adapted to be coupled to a limit switch, and has an inner surface and an outer surface. The inner surface defines a limit switch cavity that is dimensioned to have a portion of a limit switch movably disposed therein. The outer surface has a reset key groove formed therein. The reset key opening is formed in the switch head and extends between the inner surface and a portion of the reset key groove. The reset key is disposed within the reset key groove and extends at least partially into the reset key opening. The reset key is movable, relative to the switch head, between a switch unlock position and a switch lock position.

In another embodiment, a limit switch assembly includes a switch housing, a limit switch, and a reset key assembly. The limit switch is disposed at least partially within the switch housing and is movable between a first position and a second position. The reset key assembly is coupled to the switch housing and is configured to selectively maintain the limit switch in the second position, the reset key assembly includes a switch head, a reset key opening, and a reset key. The switch head is coupled to the switch housing and includes an inner surface and an outer surface. The inner surface defines a limit switch cavity within which a portion of the limit switch is movably disposed, and the outer surface has a reset key groove formed therein. The reset key opening is formed in the switch head and extends between the inner surface and a portion of the reset key groove. The reset key is disposed within the reset key groove and extends at least partially into the reset key opening. The reset key is movable, relative to the switch head, between a switch unlock position, in which the reset key does not prevent limit switch movement between the first and second positions, and a switch lock position, in which the reset key prevents the limit switch from moving from the second position to the first position.

In yet another embodiment, a limit switch assembly includes a switch housing, a limit switch, and a reset key assembly. The limit switch is disposed at least partially within the switch housing and is movable between a first position and a second position. The reset key assembly is coupled to the switch housing and is configured to selectively maintain the limit switch in the second position. The reset key assembly includes a switch head, a reset key opening, a spring cavity, a reset key, a reset key bias spring, and a seal ring. The reset key assembly is coupled to the switch housing and includes an inner surface and an outer surface. The inner surface defines a limit switch cavity within which a portion of the limit switch is movably disposed, and the outer surface has a reset key groove formed therein. The reset key opening is formed in the switch head and extends between the inner surface and a portion of the reset key groove. The spring cavity is formed in the switch head and is disposed between the reset key groove and the reset key opening. The reset key is disposed within the reset key groove and extends at least partially into the reset key opening. The reset key is movable, relative to the switch head, between a switch unlock position, in which the reset key does not prevent limit switch movement between the first and second positions, and a switch lock position, in which the reset key prevents the limit switch from moving from the second position to the first position. The reset key bias spring is disposed within the spring cavity and engages a portion of the reset key. The reset key bias spring supplies a bias force to the reset key that biases the reset key toward the switch lock position. The seal ring surrounds a portion of the reset key and engages the reset key opening. The reset key groove and the reset key are dimensioned such that the reset key does not extend outside of the reset key groove.

Furthermore, other desirable features and characteristics of the limit switch and the reset key 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

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

FIG. 1 depicts a plan view of a portion of one embodiment of a limit switch assembly；

FIGS. 2 and 3 depict cross section plan views of the limit switch assembly of FIG. 1 with limit switch in a first position and a second position, respectively；

FIG. 4 depicts an exploded view of an embodiment of a reset key assembly that may be used with the limit switch assembly depicted in FIGS. 1-3；

FIGS. 5 and 6 depict exploded view and an assembled cross section view, respectively, of another embodiment of a reset key assembly that may be used with the limit switch assembly depicted in FIGS. 1-3； and

FIGS. 7A-7D depict top views of the limit switch assembly of FIG. 1 with a reset key assembly mounted in different orientations relative to the switch housing.

DETAILED DESCRIPTION

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.

Referring to FIGS. 1-3, a plan view (FIG. 1) , and cross section plan views (FIGS. 2 and 3) , of a portion of one embodiment of a limit switch assembly 100 are depicted. The depicted limit switch assembly 100 includes, a switch housing 102, a reset key assembly 104, and an actuator 106. The switch housing 102 may be variously configured and implemented. In the depicted embodiment, the switch housing 102 is coupled to the reset key assembly 104 and includes at least a switch opening 202 and a switch spring retainer 204. Although the switch opening 202 and switch spring retainer 204 are the only features of the switch housing 102 that are described with any detail herein, it will be appreciated that the switch housing 102 may be configured and implemented with numerous other features that are either not described, not depicted, or both.

As shown more clearly in FIGS. 2 and 3, a limit switch 206 and a switch bias spring 208 are each disposed at least partially within the switch housing 102, and more specifically within the switch opening 202. The limit switch 206 is movable between a first position, which is the position depicted in FIG. 2, and a second position, which is the position depicted in FIG. 3. As FIGS. 2 and 3 further depict, the switch spring retainer 204, together with an associated spring retainer feature 208 on the limit switch 206, retains a switch bias spring 212 in place within the switch housing 102. The switch bias spring 212 supplies a bias force to the limit switch 206 that biases the limit switch toward the first position. Although the depicted limit switch 206 is configured as a plunger type switch that translates within the switch opening 202, and the switch bias spring 212 is configured as a coil spring, one or both of these devices may be variously configured and implemented.

The reset key assembly 104 is coupled to the switch housing 102 and is configured to selectively maintain the limit switch 206 in the second position. The depicted reset key assembly includes a switch head 214, a reset key opening 216, and a reset key 218. The switch head 214 is coupled to the switch housing 102 and includes an inner surface 222 and an outer surface 224. The inner surface 222 defines a limit switch cavity 226, and the outer surface 224 has a reset key groove 228 formed therein. The limit switch cavity 226 is dimensioned such that portion of the limit switch 206 is movably disposed therein.

The reset key opening 216 is formed in the switch head 214 and extends between the inner surface 222 and a portion of the reset key groove 228. The reset key 218 is disposed within the reset key groove 228 and extends at least partially into the reset key opening 216. The reset key 218 is movably disposed within the switch head 214. More specifically, and as shown most clearly in FIGS. 2 and 3, the reset key 218 is movable, relative to the switch head 214, between a switch unlock position, which is the position depicted in FIG. 2, and a switch lock position, which is the position depicted in FIG. 3.

With reference now to FIG. 4, in combination with FIGS. 2 and 3, it is noted that the reset key 216 includes a manual reset portion 215 and a switch engagement portion 217. The manual reset portion 215 is disposed within the reset key groove 228 and is accessible via one or more fingers or via a tool. The reset key 216 and the reset key groove 228 are dimensioned such that, when the reset key 216 is installed in the switch head 214, the reset key 216, and more specifically the manual reset portion 215, does not extend outside of the reset key groove 228. The manual reset portion 215, at least in the depicted embodiment, is configured as a rectangular prism, and the reset key groove 228 is suitably dimensioned to receive the manual reset portion 215 therein. It will be appreciated that the manual reset portion 215 and the reset key groove 228 may be configured and implemented using various sizes, shapes, and configurations.

Regardless of the size, shape, and configuration of the manual reset portion 215, the switch engagement portion 217 extends from the manual reset portion 215 and into the reset key opening 216. As shown most clearly in FIG. 4, the depicted switch engagement portion 217 has at least two features formed therein, a spring groove 402 and a seal groove 404. A reset key bias spring 406 is at least partially disposed within the spring groove 402, and is also disposed within a spring cavity 408 that is formed in the switch head 214 between the reset key groove 228 and the reset key opening 216.

The reset key bias spring 406 engages a portion of the reset key 218, and more specifically the switch engagement portion 217 via the spring groove 402, and supplies a bias force to the reset key 218. The bias force supplied by the reset key bias spring 406 biases the reset key 218 toward the switch lock position. Although the reset key bias spring 406 may be variously configured and implemented, in the depicted embodiment it is implemented using a leaf spring formed of sheet metal.

A seal ring 412 is disposed within the seal groove 404. As may be appreciated, when the reset key 218 is installed in the switch head 214, the seal ring 412 engages the reset key opening 216. Thus, the seal ring 412 provides a suitable seal between the limit switch cavity 226 and the external environment.

In another embodiment, which is depicted in FIGS. 5 and 6, the switch engagement portion 217 includes the seal groove 404, does not include the spring groove 402. A ring seal 412 may be disposed within the seal groove 404 and, although the embodiment depicted in FIGS. 5 and 6 does include a reset key bias spring 502, the reset bias spring 502 is configured differently. In particular, the depicted reset key bias spring 502 is implemented using a coil spring that, when installed surrounds at least a portion of the switch engagement portion 217. As FIGS. 5 and 6 also depict, this embodiment may, if needed or desired, additionally include a spring stop 504. The spring stop 504, at least in the depicted embodiment, is disposed adjacent the reset key opening 216. The reset key bias spring 502 engages the spring stop 504 and the manual reset portion 215 and supplies the bias force to the reset key 218 that biases the reset key 218 toward the switch lock position.

Returning once again to FIGS. 1-3, it is seen that the switch head 214 further includes an actuator opening 112. The actuator 106 is rotationally mounted within the actuator opening 112, and extends into the limit switch cavity 226 and contacts the limit switch 206. When the actuator 106 is in the position depicted in FIGS. 1 and 2, the limit switch 206 is in the first position. Thereafter, if a force of sufficient magnitude is supplied to the actuator 106 that causes it to rotate, it will supply a force to the limit switch 206 that causes the limit switch 206 to move, against the force supplied from the switch bias spring 212, from the first position to the second position.

When limit switch 206 is moved to the second position, the reset key 216 moves, under the force of the reset key bias spring 406, from the switch unlock position to the switch lock position. As a result, the switch engagement portion 217 engages a portion of the limit switch 206 and maintains it in the second position. Thereafter, to reset the limit switch 206 to the first position, an operator, using one or more fingers or a tool, uses the manual reset portion 215 to move the reset key 218, against the force of the reset key bias spring 406, back to the switch unlock position. As a result, the limit switch 206, via the bias force supplied from the switch bias spring 216, moves back to the first position.

The limit switch and limit switch reset key assemblies described herein significantly reduce the likelihood of (or even eliminates) inadvertent operations. The assemblies also reduce overall part quantity and cost associated with the limit switch assembly, and does not limit where and how the limit switch can be mounted. Moreover, as depicted in FIGS. 7A-7D, the reset key assembly 104 embodiments (and all associated equivalents) depicted and described herein may be mounted, for example, in a plurality of orientations relative to the switch housing 102.

In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Numerical ordinals such as “first, ” “second, ” “third, ” etc. simply denote different singles of a plurality and do not imply any order or sequence unless specifically defined by the claim language. The sequence of the text in any of the claims does not imply that process steps must be performed in a temporal or logical order according to such sequence unless it is specifically defined by the language of the claim. The process steps may be interchanged in any order without departing from the scope of the invention as long as such an interchange does not contradict the claim language and is not logically nonsensical.

Furthermore, depending on the context, words such as “connect” or “coupled to” used in describing a relationship between different elements do not imply that a direct physical connection must be made between these elements. For example, two elements may be connected to each other physically, electronically, logically, or in any other manner, through one or more additional elements.

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.

Claims

A reset key assembly for a limit switch, comprising:

a switch head adapted to be coupled to a limit switch, the switch head having an inner surface and an outer surface, the inner surface defining a limit switch cavity, the limit switch cavity dimensioned to have a portion of a limit switch movably disposed therein, the outer surface having a reset key groove formed therein；

a reset key opening formed in the switch head and extending between the inner surface and a portion of the reset key groove； and

a reset key disposed within the reset key groove and extending at least partially into the reset key opening, the reset key movable, relative to the switch head, between a switch unlock position and a switch lock position.
The reset key assembly of claim 1, further comprising:

a spring cavity formed in the switch head and disposed between the reset key groove and the reset key opening； and

a reset key bias spring disposed within the spring cavity and engaging a portion of the reset key, the reset key bias spring supplying a bias force to the reset key that biases the reset key toward the switch lock position.
The reset key assembly of claim 2, wherein:

the reset key has a spring groove formed in a portion thereof； and

the reset key bias spring is at least partially disposed within the spring groove.
The reset key assembly of claim 3, wherein the reset key bias spring comprises a leaf spring.
The reset key assembly of claim 2, wherein the reset key bias spring comprises a coil spring.
The reset key assembly of claim 1, further comprising a seal ring surrounding a portion of the reset key and engaging the reset key opening.
The reset key assembly of claim 1, wherein the reset key groove and the reset key are dimensioned such that the reset key does not extend outside of the reset key groove.
A limit switch assembly, comprising:

a switch housing；

a limit switch disposed at least partially within the switch housing and movable between a first position and a second position； and

a reset key assembly coupled to the switch housing and configured to selectively maintain the limit switch in the second position, the reset key assembly comprising:

a switch head coupled to the switch housing and including an inner surface and an outer surface, the inner surface defining a limit switch cavity within which a portion of the limit switch is movably disposed, the outer surface having a reset key groove formed therein,

a reset key opening formed in the switch head and extending between the inner surface and a portion of the reset key groove, and

a reset key disposed within the reset key groove and extending at least partially into the reset key opening, the reset key movable, relative to the switch head, between a switch unlock position, in which the reset key does not prevent limit switch movement between the first and second positions, and a switch lock position, in which the reset key prevents the limit switch from moving from the second position to the first position.
The limit switch assembly of claim 8, further comprising:

a spring cavity formed in the switch head and disposed between the reset key groove and the reset key opening； and

a reset key bias spring disposed within the spring cavity and engaging a portion of the reset key, the reset key bias spring supplying a bias force to the reset key that biases the reset key toward the switch lock position.
The limit switch assembly of claim 9, wherein:

the reset key has a spring groove formed in a portion thereof； and

the reset key bias spring is at least partially disposed within the spring groove.
The limit switch assembly of claim 10, wherein the reset key bias spring comprises a leaf spring.
The reset key assembly of claim 9, wherein the reset key bias spring comprises a coil spring.
The limit switch assembly of claim 8, further comprising a seal ring surrounding a portion of the reset key and engaging the reset key opening.
The limit switch assembly of claim 8, wherein the reset key groove and the reset key are dimensioned such that the reset key does not extend outside of the reset key groove.
The limit switch assembly of claim 8, wherein:

the switch head further includes an actuator opening；

the limit switch assembly further comprises an actuator； and

the actuator is rotationally mounted within the actuator opening, and extends into the limit switch cavity and contacts the limit switch.