This invention relates to connection techniques employed in manufacturing processes for dynamoelectric machines. While the invention is described with particular emphasis with respect to its use in electrical motors, those skilled in the art will recognize the wider applicability of the inventive principles disclosed hereinafter.
Dynamoelectric machines, such as single phase induction motors having at least one main winding and an auxiliary or start winding frequently utilize switch assemblies for selectively controlling a number of circuits. For example, in single phase induction motors, it is common practice to employ a switch to de-energize the start winding once the motor reaches a predetermined operating speed and at the same time to selectively regulate other circuitry. Many different kinds of motors, for example, single and multi speed, and reversible motors incorporate winding circuit controlling swithces which are actuated in response to a particular motor speed. It is desirable for the same basic switch unit to be capable of use in conjunction with the various motors without necessitating extensive modification of the switch assembly. These same motors often are employed in a variety of applications including, for example, domestic appliances which require selective control of both internal motor and external circuits. Consequently, the switch unit assemblies are highly versatile in application.
One form of switch assembly finding general application is shown and disclosed in the U.S. patent to Zagorski, U.S. Pat. No. 3,313,905. In general, this type of switch assembly includes an enclosure having a plurality of electrical terminals extending through the enclosure for making the aforesaid electrical connections. The various terminals are selectively energized through a use of a plunger assembly which is operatively connected to a centrifugal actuator conventionally mounted to the shaft of a rotor assembly of the dynamoelectric machine. When manufacturing the various motor types described above, the switch assembly is mounted to the motor so that the terminals extending through the switch enclosure are accessible after the motor components are assembled. Thereafter, the terminals are selectively interconnected with the motor windings and other external circuits to provide the desired operating characteristics.
In the past, it has been conventional to use a flexible wire jumper between various ones of the terminal as required by the desired switch motor operating characteristics. While this procedure works for its intended purpose, the construction of the flexible jumper itself requires a number of steps including stripping of insulation coating from the particular wire, and crimping the terminal to the wire. As will be appreciated by those skilled in the art, jumper failure often can and does occur at the crimp between the terminal and the flexible wire connector. In addition, confusion can exist in wire placement during motor assembly. That is to say, flexible jumpers can be connected along a variety of locations at the motor switch. It is relatively expensive to presize flexible jumpers to some specific length. In practice, this means both additional care in connecting the jumper and careful inspection of that connection are required.
The invention disclosed hereinafter overcomes these prior art deficiencies by providing a nonflexible, integral jumper formed from a single piece of conductive material. In the preferred form of the invention, the jumper is a single strip of material terminated on each end by a formed electrical connection means compatible with the particular switch assembly terminals being employed. Depending upon the switch terminal configuration and spacing, the strip conductive material can be sized for a particular terminal spacing with respect to the switch assembly, or the jumper can be made to fit a variety of terminal spacings along the switch assembly by selective prestressing of the strip. Since the material strip can be sized easily for a particular applications, it reduces the possible connection alternatives available to an installer, yet simultaneously provides a single size structure that is compatible with various spacing arrangements between terminals at the switch assembly.
One of the objects of this invention is to provide a low cost jumper assembly for a switch assembly of a dynamoelectric machine.
Another object of this invention is to provide a preformed jumper assembly that reduces the possible connection alternatives to the installer of the jumper assembly.
Another object of this invention is to provide a jumper assembly which, although presized, may be formed to a variety of spacings corresponding to the terminal spacing of the switch assembly with which it finds application.
Another object of this invention is to provide a jumper assembly formed from a single piece of material, all the components of the jumper assembly being integrally formed from that single material piece.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.