Patent Application
20100282578
This invention relates generally to disconnect assemblies for electrical joints.
In known air conditioning disconnect (ACDC) systems, a disconnect assembly has a pullout assembly with conductive jaws separable from “conductive connectors” affixed in a base assembly to conductive lugs. The conductive connectors are bent at a 90 degree angle to receive the respective conductive jaws. The pull out assembly includes a full jaw connected to a handle. The base assembly includes a lug that is secured to a base of the base assembly and a corresponding conductive connector. In the conductive position the conductive connectors of the base assembly are mated to a pair of the full jaws of the pullout assembly, allowing current to flow from one lug, which receives line current, across the pair of full jaws, to another lug, which provides the line current to the air conditioning load. The full jaw includes two pieces of copper that are bent to form a jaw-like arrangement. Copper is expensive. In addition, in existing designs, numerous parts are required to form the disconnect assembly. The lug is spaced away from the 90 degree connectors that receive the jaws of the pullout assembly. Rivets or screws are required to fasten the two jaw halves together, and for every jaw, a corresponding 90 degree connector is required. In short, prior-art systems use too many parts and are expensive because they overuse the amount of copper that is needed. They also present a number of joints, and joints are undesirable because they produce heat due to electrical current crowding at the transitions and reduce the delivery efficiency of the current.
What is needed, therefore, among other things, is a disconnect assembly that requires as few parts as possible while reducing the overall amount of copper used compared to existing designs. The present disclosure fulfills these and other needs.
According to some embodiments of the present invention, in an electrical circuit where an electrical connection needs to be made or broken, a disconnect assembly is placed in the circuit that allows an operator or a device to disconnect the load from the electrical circuit. The disconnect assembly includes a pullout assembly that has metal blades, which provide the electrical path for current between a line and a load connection, that are inserted into blade-receiving extensions and held in place there as the pullout assembly is inserted into or removed from a base assembly to make or break electrical connections. The base assembly includes a lug-jaw connector that is composed of a lug and an adjacent half jaw. The half jaw uses less copper compared to previous designs, which have used a full jaw to make the electrical connection. The half jaw can be secured to the lug through friction or an attachment means such as a screw. The half jaw may resemble a clip such that when the conductive blade is inserted between, and in contact with, the half jaw and the lug, the blade is held securely in place so that current can flow from the line to the load side of the circuit. To break the electrical connection, the pullout assembly is removed manually or automatically so that the conductive blade thereof physically detaches from the lug-jaw connectors. When the disconnect device is removed an open circuit is created between the line and load portions of the circuit and no current can flow. Compared to previous designs, the disconnect assembly of the present invention advantageously uses far fewer parts, less of the expensive copper conductor, and presents fewer sharp transitions at the joints to electrical current, among other benefits.
The foregoing and additional aspects of the present invention will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided next.
The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
The flat blade 110a includes two exposed portions 112a,b for connection to respective lug-jaw connectors 114a,b,c,d, as explained below. The flat blade 110 preferably has a rectangular shape and can be tapered at its ends to permit the flat blades 110a,b to be easily inserted into the respective channels 108. While described as “flat,” the conductive blades 110a,b might also be formed in contoured shapes and individually fitted between each pair of blade-receiving extensions 106a-f although such an embodiment would likely increase part count and assembly steps. It should be emphasized that the blades 110 fit snugly into the channels 108 without any additional attachment means, such as screws, rivets, or other fasteners, to hold them therein. Although three blade-receiving extensions 106 are shown to receive one blade, only a minimum of one blade-receiving extension may be required to receive the blade through a channel of the blade-receiving extension.
The pullout assembly 102 preferably includes a pullout handle 116 connected to the face portion 104. The pullout handle 116 can be molded and composed of a plastic-based dielectric material. In applications such as an air conditioning disconnect (ACDC) in which the electric circuit includes an air conditioning load or in which the electric circuit is incorporated into a load center, the handle 116 is grasped by the operator and pulled away from the base assembly 104 to cause the blades 110a,b to separate from the respective lug-jaw connectors 114. In the illustrated example of
In applications in which the assembly 100 is incorporated into a circuit breaker or a switch, the handle 116 is not needed, and a conventional mechanism is coupled to the pullout assembly 102 to disconnect the pullout assembly 102 from the electrical circuit. The mechanism conventionally urges the flat blade out of the lug-jaw connectors 114. It should be emphasized that the assembly 100 of the present disclosure can be incorporated into any electrical circuit that requires the making and breaking of an electrical connection anywhere in the circuit. This assembly 100 is interposed into the circuit at the point where an electrical disconnect is needed.
The base assembly 104 includes the lug-jaw connectors 114a-d, which are conventionally attached to a base 118 of the base assembly 104. One of the lug-jaw connectors 114d is shown exploded away from the base 118 in
Any of the blades, lugs, and half jaws described herein can be composed of a conductive material, including aluminum, copper, or alloys thereof. Specifically, any of the half jaws described herein can be composed of a material that includes copper, such as spring copper which, when bent, can return to its original position. An example of a suitable copper includes 151 Cu or 155 Cu.
While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
