Patent Application
20090278637
The application generally relates to an electromagnetic relay. The application relates more specifically to an electromagnetic relay having a relay actuator with an automated overtravel adjustment for the electrical contacts.
A relay is an electromagnetically actuated, electrical switch. Conventional relays include stationary contacts and moving contacts corresponding with the stationary contacts. When the relay is electromagnetically actuated, the moving contacts engage or disengage with the stationary contacts, to respectively close or open an electrical circuit.
A conventional relay has a base structure, a housing, a relay coil, an armature, a pusher and a contact system. The base structure and housing are made of an electrically insulating material and support and enclose the operative electromagnetic parts of the relay. The relay coil has a coil and a magnetically permeable core connected to the tilting armature to move the armature. The coil is a cylindrical hollow member with a rectangular internal cross section corresponding to a cross section of the core, and is spring loaded to return to a specified position when the coil is de-energized. The pusher links the tilting armature and the contact system.
When manufacturing a relay, the relay stationary contact springs and moving contact springs are set to make contact concurrently when closing. Both the moving spring and stationary springs include metallic pads or tips that serve as the mutual point of contact. The spring tips absorb wear and tear caused by the actuation force, electrical arcing, repetitious movements, and other deteriorating factors. To account for this deterioration due to repeated use, an over-travel adjustment must be provided. This process involves manipulating the contact springs, which are generally made from copper, copper alloys or similar conductive materials. The contact springs must be manually bent, turned, twisted or otherwise manipulated to attempt to set a uniform overtravel position for the plurality of contact springs. Due to the mechanical properties of the metallic contact springs, it is difficult to achieve a reliable and precise overtravel setting.
There is a need for an apparatus and system for automatically achieving a uniform overtravel adjustment for contact springs in an electromagnetic relay.
Intended advantages of the disclosed systems and/or methods satisfy one or more of these needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.
One embodiment relates to an electromagnetic relay. The electromagnetic relay has a relay coil, an armature, a pusher and a contact system. The armature is pivotably actuated by the relay coil, and linked to a trailing end of the pusher to drive a forward edge of the pusher to operate the contact system. The contact system has at least one stationary contact spring and at least one moveable contact spring having a gap separating the stationary contact spring and the moveable contact spring. The moveable contact springs are connected at a first end to the pusher and at a second end to a first pivot point. As the armature pivots, the armature moves the pusher linearly between a forward position and a return position in response to an electromagnetic force generated by the relay coil. The stationary springs have a connection point to a base structure portion, and include a flex point in the stationary spring adjacent to the base structure portion. The movement of the pusher causes the one stationary contact springs and the moveable contact springs to engage or disengage.
Another embodiment relates to a contact system for an electromagnetic relay having an armature pivotably actuated by a relay coil linked to a trailing end of a pusher to drive a forward edge of the pusher. The contact system includes at least one stationary contact spring and at least one moveable contact spring having a gap separating the stationary contact springs and the moveable contact springs. The moveable contact springs are connected at a first end to the pusher and at a second end to a first pivot point. As the armature pivots, the armature moves the pusher linearly between a forward position and a return position in response to an electromagnetic force generated by the relay coil. The at least one stationary spring includes a connection point to a base structure portion. The stationary spring includes a flex point adjacent to the base structure portion. The movement of the pusher causes the stationary contact springs and the moveable contact springs to engage or disengage, and adjust an angle of the stationary contact spring.
A further embodiment is directed to a method of adjusting overtravel angle of a plurality of contact springs in an electromagnetic relay. The method includes positioning an overtravel adjustment fixture on one side of a plurality of stationary contacts of the relay, and a plurality of moveable contacts corresponding to the plurality of stationary contacts on a second side of the plurality of stationary contacts opposite from the overtravel adjustment fixture; aligning a plurality of pushrods of the overtravel adjustment fixture with the plurality of contact springs; moving the plurality of moveable contacts in the direction of the plurality of stationary contacts until each moveable contact of the plurality of moveable contacts makes an initial contact with a corresponding stationary contact of the plurality of stationary contacts; and setting an overtravel angle associated with each contact of the plurality of moveable contacts by pushing each stationary contact an additional distance after sensing the initial contact of all of the plurality of moveable contacts and the corresponding stationary contacts.
Certain features of the embodiments described herein are a simplified, easily replicated and precise mechanism for overtravel adjustment in an electromagnetic relay.
Another feature is an automated system that allows for more consistent and uniform overtravel adjustment of multiple relay contacts than that produced by the manual adjustment method of bending each contact spring.
Yet another feature is a moveable relay contact spring having a pre-bias angle.
Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Referring now to
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The stationary contact springs 26 are connected at one end 26a in the base structure 28a of the relay housing 66 (See, e.g.,
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It should be understood that the application is not limited to the details or methodology set forth in the following description or illustrated in the figures. It should also be understood that the phraseology and terminology employed herein is for the purpose of description only and should not be regarded as limiting.
While the exemplary embodiments illustrated in the figures and described herein are presently preferred, it should be understood that these embodiments are offered by way of example only. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims. The order or sequence of any processes or method steps may be varied or re-sequenced according to alternative embodiments.
It is important to note that the construction and arrangement of the relay operating mechanism 10, as shown in the various exemplary embodiments, is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application.
It should be noted that although the figures herein may show a specific order of method steps, it is understood that the order of these steps may differ from what is depicted. Also two or more steps may be performed concurrently or with partial concurrence. It is understood that all such variations are within the scope of the application. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.
