Electricity: circuit makers and breakers – Electric switch details – Contact
Reexamination Certificate
2001-09-21
2004-07-06
Luebke, Renee (Department: 2833)
Electricity: circuit makers and breakers
Electric switch details
Contact
C200S247000, C200S280000, C200S281000
Reexamination Certificate
active
06759612
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a movable contact, and more particularly to a movable contact used in a pusher assembly of a contact block and to a method of assembling a pusher assembly having a movable contact.
BACKGROUND OF THE INVENTION
Conventional contact blocks, which can be configured both in a 1-pole arrangement or a 2-pole arrangement, include a number of contact elements. When used in a 1-pole arrangement, a movable contact only requires contact surfaces or pads formed on one side of the movable contact. However, when used in a 2-pole arrangement, the movable contact must have contact surfaces formed on both sides of the movable contact. Such movable contacts require an expensive manufacturing process to create a contact surface on both sides of the movable contact.
For example, some conventional movable contacts are produced using a “tape-welding” process in which four continuous strips of silver are welded to both sides of both ends of a strip of copper alloy from which the movable contacts are punched. Other conventional movable contacts are produced by forcing a silver wire through punched holes in the contact blade and then coining the silver wire both top and bottom to form contact surfaces on both sides of the blade. Because 2-pole contact blocks are less common than 1-pole contact blocks, double-sided movable contacts found in conventional 2-pole contacts are produced in lower volume, and are therefore even more costly.
Further, contact block assemblies are often assembled by hand, and often have a number of springs which make the assembly difficult. In particular, when assembling components of a conventional contact block assembly, it may be necessary for an assembler to compress a spring in order to insert another component of the assembly. In such situations, it is often common that the spring becomes dislodged, and in many cases may becomes lost. More importantly, the difficulty in assembling the contact block may cause additional fatigue on a worker and an increase in assembly errors.
Such problems are particularly true of pusher assemblies, which often have smaller springs that are more difficult to manipulate with the human hand. In particular, inserting a small spring into a pusher by compressing the spring can be difficult. Further, when a pusher assembly is assembled in a contact block, it is beneficial if the components of the pusher assembly are secured within the pusher assembly. That is, the pusher assembly could be picked up and placed in the contact block housing without any fear that components of the pusher assembly would become dislodged. Accordingly, there is a need for a movable contact which can be used as a pair of movable contacts for a 2-pole contact block assembly.
SUMMARY OF THE INVENTION
The present invention relates to a movable contact having a pair of contact elements extending from each end of a body portion. Each contact element comprises a pair of contact fingers, wherein each contact finger has an inclined portion leading to a contact surface which is substantially parallel to the body portion.
According to another aspect of the invention, a pusher assembly for use in a contact block assembly comprises a housing portion, a window formed in the housing portion, and a movable contact positioned within the window. The movable contact comprises a body portion and a pair of contact portions coupled to the ends of the body portion. Each contact portion has a pair of contact fingers having an inclined portion and a contact element.
According to another aspect of the invention, two movable contact having contact fingers with an inclined portion and a contact element could be placed back to back.
According to yet another aspect of the invention, a pusher assembly for use in a contact block assembly comprises a pusher, a window extending through the pusher, a first movable contact positioned within the window, and a second movable contact positioned adjacent to the first movable contact within the window.
According to another aspect of the invention, a method of assembling a pusher assembly having a movable contact comprises the steps of inserting the first movable contact within a pusher; inserting a second movable contact within the pusher; and retaining the first movable contact and the second movable contact within the pusher by a spring.
It is an object of the invention to provide a movable contact which can be used in either a 1-pole or a 2-pole contact block assembly.
It is a further object of the invention to provide a movable contact which can be coupled with a second movable contact to form a pair of movable contacts for use in a 2-pole contact block assembly.
It is a further object of the invention to provide a pusher assembly for receiving a pair of movable contacts for use in a 2-pole arrangement in a contact block assembly.
Finally, it is an object of the invention to provide a method for assembling a contact block assembly having a pair of movable contacts.
Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings.
REFERENCES:
patent: 3324270 (1967-06-01), Lacan
patent: 3436497 (1969-04-01), Mading
patent: 3505625 (1970-04-01), Nielsen et al.
patent: 4443675 (1984-04-01), Drexler et al.
patent: 4634819 (1987-01-01), Ikeda
patent: 6114639 (2000-09-01), Hall et al.
Luebke Renee
Siemens Energy & Automation
LandOfFree
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