Patent Application
20180350531
The present invention relates to contact levers for use in electrical switch assemblies.
In certain existing electrical switch assemblies, such as snap-action type switch assemblies, when relatively small amount of physical force is applied to an actuator member, a contact lever operably-connected with the actuator member via a tension spring will quickly and reliably lever a movable contact member from a position of electrical communication with one stationary contact member, into a position of electrical communication with another stationary contact member of the electrical switch assembly. Such electrical switch assemblies will typically utilise a contact lever upon which the movable contact is mounted to allow movement of the movable contact from electrical communication with the one stationary contact into electrical communication with the other. The contact lever will typically comprise a pair of substantially parallel lever arms separated by a gap through which the tension spring may suitably pass during operation of the electrical switch assembly. One disadvantage with contact levers of this configuration is that they tend to be susceptible to deformation in certain circumstances due to exposure to heat stress—for instance, when used in power tools such as angle grinders and the like, requiring high current rating capacity.
The present invention seeks to alleviate at least one of the above-described problems.
The present invention may involve several broad forms. Embodiments of the present invention may include one or any combination of the different broad forms herein described.
In a first broad form, the present invention provides a contact lever for use in an electrical switch assembly so as to allow selectable movement within the switch assembly of a contact lever contact member from electrical connection with a first stationary contact member into electrical connection with a second stationary contact member, the contact lever including: first and second lever arms that are connected at respective first ends to the contact lever contact member; said first and second lever arms having respective second ends, and, said first and second lever arms being configured to extend away from the contact member and to terminate at their respective second ends; a gap disposed between the first and second lever arms which separates the first and second lever arms as they extend away from the contact member, and wherein the gap is configured to allow movement of a spring element of the switch assembly therethrough; and a bridge member configured for connection with the first and second lever arms so as to traverse the gap separating the first and second lever arms.
Preferably, the bridge member may be configured for connecting the first and second lever arms at regions along the first and second lever arms so as to define an aperture between the bridge member and the contact lever contact member.
Preferably, the bridge member may include a substantially U-shaped configuration.
Preferably, the present invention may include a contact lever contact member plate having at least one of a recess, aperture or abatement disposed therein configured for securement of the contact lever contact member thereto.
Preferably, the present invention may include an aperture configured for securement with a first end of a tension spring of the switch assembly.
Preferably, the bridge member may include a conductive material.
Preferably, the bridge member may include a copper alloy material.
Preferably, the bridge member may be integrally formed with the first and second lever arms.
Preferably, the switch assembly may include a microswitch assembly.
In another broad form, the present invention provides a contact lever for use in an electrical switch assembly so as to allow selectable movement within the switch assembly of a contact lever contact member from electrical connection with a first stationary contact member into electrical connection with a second stationary contact member, said contact lever including: first and second lever arms that are connected at respective first ends to a contact lever contact member, said first and second lever arms having respective second ends, and, said first and second lever arms being configured to extend away from the contact member and to terminate at their respective second ends; a gap disposed between the first and second lever arms which separates the first and second lever arms as they extend away from the contact member, and wherein the gap is configured to allow movement of a spring element of the switch assembly therethrough; wherein the contact lever includes a contact lever layer bonded or joined to the contact lever to form a multi-layer structure of increased cross-sectional thickness.
Preferably, the contact lever layer may include a further contact lever that is bonded or joined to the contact lever to form the multi-layer structure of increased cross-sectional thickness.
Preferably, the present invention may include a bridge member configured for connection with the first and second lever arms so as to traverse the gap separating the first and second lever arms.
Preferably, the bridge member may be configured for connecting the first and second lever arms at regions along the first and second lever arms so as to define an aperture between the bridge member and the contact lever contact member.
Preferably, the bridge member may include a substantially U-shaped configuration.
Preferably, the present invention may include a contact lever contact member plate having at least one of a recess, aperture or abatement disposed therein configured for securement of the contact lever contact member thereto.
Preferably, the present invention may include an aperture configured for securement with a first end of a tension spring of the switch assembly.
Preferably, the bridge member may include a conductive material.
Preferably, the bridge member may include a copper alloy material.
Preferably, the bridge member may be integrally formed with the first and second lever arms.
Preferably the switch assembly may include a microswitch assembly.
In another broad form, the present invention provides an electrical switch assembly including a contact lever in accordance with any one of the features of the first broad form of the present invention.
The present invention will become more fully understood from the following detailed description of a preferred but non-limiting embodiments thereof, described in connection with the accompanying drawings, wherein:
Preferred embodiments of the present invention will now be described herein with reference to
In a prior art microswitch assembly as shown in
Referring now to
A contact lever is also movably mounted within the main body (30A) of the housing about a hinge member. The contact lever is shown in stand-alone form in
The contact member plate (32) also includes a further aperture (33) configured for anchoring one end of the tension spring (36) (with the other end of the tension spring being anchored to a second fixed anchor point (42) moulded in the internal surface of the housing main body (30A)) such that in use the body of the tension spring (36) will freely be received within the gap (31C) when operably-connected with and during ordinary operation of the contact lever. In contrast to the prior art contact lever configuration described above, a bridge member (35) is configured for connecting the first and second lever arms (31A,31B) whereby it traverses the gap (31C) separating the first and second lever arms (31A,31B) and provides structural support for the contact lever. In particular, the bridge member (35) assists in alleviating deformation of the contact lever due to heat stress and/or mechanical stress applied to the material of the contact lever by substantially supporting the first and second lever arms in their fixed spaced-apart relationship. Furthermore, the novel inclusion of the bridge member (35) assists in providing a stronger overall structure for the contact lever which may assist in increasing overall production yield of such contact lever components during manufacture. In particular, in contrast to prior art contact levers described herein which may be relatively susceptible to breakage when stamped out during production due to their bridge-less structure, such problems are alleviated during stamping out due to the overall stronger and/or more rigid structure of the contact lever. Furthermore, as the novel inclusion of the bridge member (35) improves the overall strength of the contact lever structure, copper alloys (or any other suitable material known to persons skilled in the art) of lower stiffness may be utilised which tends to improve conductivity through the contact lever and thereby allows for higher current rating capability. Furthermore, in these embodiments of the present invention, the bridge member (35) is shaped and dimensioned in a substantially U-shaped configuration so as to not unduly block movement of the tension spring (36) within the gap (31C). Although in the embodiment shown in
The contact lever may typically be comprised by a conductive copper alloy material and the bridge member (35) may be either integrally formed with the contact lever, or, may be for instance welded to the contact lever arms (31A,31B) to connect the first and second lever arms (31A,31B).
An actuator member (31) is also seated in relation to the main body (30A) of the housing so that it may be depressed inwardly of the main body (30A) by relatively small amount of force applied by the user's finger. A sealing ring (41) is also provided which assists in preventing ingress or dust and water into the housing (30A) via the opening in which the actuator (31) moves.
In certain embodiments, alternatively, or, in addition to a bridge member connecting the first and second lever arms of a contact lever, a contact lever (50) may be formed by bonding or joining together two or more separate contact levers (50A,50B). For instance, as shown in
Furthermore, in yet further embodiments, instead of bonding or joining together two fully formed contact levers to increase the thickness and strength of the cross-sectional profile, it may be possible to bond or join together one or more alloy pieces to only specific regions of one contact lever so as to increase the cross-sectional thickness of only those specific regions (for instance, the lever arms (59A,59B)) of the contact lever (50). By increasing the cross-sectional thickness of the contact lever (50) in this manner, this may also assist in alleviating deformation of the contact lever (50) due to heat stress and/or mechanical stress applied to the material of the contact lever (50).
Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described without departing from the scope of the invention. All such variations and modification which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope of the invention as broadly hereinbefore described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps and features, referred or indicated in the specification, individually or collectively, and any and all combinations of any two or more of said steps or features.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that prior art forms part of the common general knowledge.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17105471.8 | Jun 2017 | HK | national |
| 17109512.1 | Sep 2017 | HK | national |
