Connector having flexible spring action

Abstract

 A service connector includes unitary extruded connector having a crown portion (14, 34) and depending cooperating spring elements (18, 38, 42) for forming a connection in which the conductor groove provides resilient contact pressure between connector elements.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to connectors, particularly to connectors utilizing set screws for securing electrical wires in a connector with sufficient contact pressure to establish a reliable electrical contact.

[0002] In the use of set screw electrical connectors it is necessary to provide for a constant pressure on the wire with the connector having sufficient resiliency to withstand the pressure applied by the set screw on the electrical wire. Inadequate pressure will result in a faulty connection or loss of electrical contact. It is therefore useful to provide means for operating personnel to assure that adequate set screw pressure is applied to a connector during installation.

[0003] The utilization of set screw connectors is limited to installations in which there is minimal movement or flexing of the conductor with respect to the connector. Excessive movement or flexing of a conductor can be caused by oscillation induced by wind changes, ice loads, longitudinal thermal expansion of the conductor, and bending of the conductor by electricians working on adjacent wiring.

[0004] When a set screw connection is made on an aluminum conductor, and the recommended tightening torque is applied to-the set screw, an excellent low resistance connection to the conductor is achieved initially. This is accomplished by the establishment of current carrying contact spots. However over the long term, the connection is susceptible to a destructive increase in resistance, should there be a disturbance to the contact spots that were initially established.

[0005] In the majority of applications, the connector will be used on high conductivity (EC) conductor which has an attendant, high creep characteristic. In addition its creep rate is increased at the elevated temperature that results from normal operating current. Thus the initial pressure on the contact spots will be reduced substantially and the initial firm grip on the conductor is reduced. This will normally not cause a change in resistance unless the conductor is moved. If however the connection is disturbed, the low resistance contact may be broken and moved to an oxidized, high resistance conductor surface. This will lead to failure of the connector.

[0006] By designing the body of the connector to have a resilient spring element that will elongate sufficiently to compensate for the creep of the conductor, then the initial contact pressure can be more nearly maintained. This, in conjunction with the use of a connector alloy such as 6061 which has a superior creep characteristic, further assists the connector to maintain contact pressure. This will keep the contact spots intact, maintain the grip on the conductor, and avoid a potential connector failure.

SUMMARY OF THE INVENTION

[0007] The present invention provides a service connector for electrical wires having a connector body with a conductor groove or cavity defined by dual cooperating spring elements cooperating with a set screw and wire connector for establishing a suitable electrical connection and for indicating when sufficient torque has been applied to the set screw in establishing the connection.

[0008] The service connector with cooperating spring elements and set screw accommodates the ordinary movements and flexing of overhead or underground power lines in service.

[0009] The service connector is suitable for a single conductor connection or for multiple conductor connections as used for a secondary junction.

OBJECTS OF THE INVENTION

[0010] It is an object of the invention to provide a service connector having dual cooperating spring elements defining a conductor groove in the connector and cooperating with the set screw for indicating a satisfactory connection has been established.

[0011] It is a further object to provide a connector having means for providing leverage so that recommended torque can be applied to a set screw.

[0012] A further object of the invention is to provide a service connector with integral spring elements enabling the connector to establish a connection capable of enduring conductor motion, as well as vibrational and other moving disturbances.

[0013] Other and further objects of the invention will occur to one skilled in the art upon the employment of the invention in practice or upon an understanding of the following detailed description of the invention.

DESCRIPTION OF THE DRAWING

[0014] A preferred embodiment of the invention has been chosen for purposes of description and is shown in the accompanying drawing in which:

FIGURE 1 is an end view of a preform of a connector in an intermediate stage of manufacture.

FIGURE 2 is an end view of a finished connector.

FIGURE 3 is a side elevational view thereof.

FIGURE 4 is a side elevational view of a connector according to the invention with the spring elements rolled inwardly toward the connector cavity.

FIGURE 5 illustrates the connector of Figure 4 with a conductor installed.

FIGURE 6 is an end view of a secondary junction utilizing the principles of the invention.

FIGURES 7 and 8 plan and side views thereof respectively.

FIGURE 9 is a fragmentary view of the connector of Figure 6 showing the positions of connector spring elements before and after conductor installation.

FIGURE 10 is a further modification of a secondary junction shown in fragmentary end view.

[0015] Referring now to FIGS 1 and 2 of the drawing, a service connector 10 of the present invention is preferably an extrusion initially as a preform 12 having a crown portion 14 and downwardly depending sidewalls 16 terminating at their lower ends in converging spring elements 18. The spring elements end faces 20 are spaced to define a gap G. The downwardly depending sidewalls and spring elements define a connector groove or cavity 22 for receiving a conductor. In the preform of Figure 1, the gap defines an opening for a mandrel support (not shown) necessary to create the interior cavity during an extrusion operation. After the preform is fabricated, the gap may be substantially closed (Fig. 2) by means of press rollers in a subsequent manufacturing operation.

[0016] A finished service connector is shown in Fig. 2 and 3 and includes the interior cavity for receiving a conductor, and a plurality of set screws 24 formed into the crown portion of the connector for entering the conductor cavity and compressing the conductor against the spring elements thereby forming a connection.

[0017] A slot 26 is formed in each sidewall of the connector by machining other suitable method for the purpose of allowing an operator to establish leverage when the set screws are being tightened to secure a conductor. To obtain such leverage, the operator will insert a suitable tool such as a screwdriver into the slot providing leverage so that the recommended torque can be applied to the each set screw utilizing an appropriate tool such as an allen wrench. The slots are also useful in centering and visually inspecting the conductor location within the connector prior to securing conductors.

[0018] The spring elements 18 and the wedge shaped conductor cavity 22 provide resilient contact pressure and wiping action as between connector and conductors located therein.

[0019] The spring elements acquire their spring action by selection of material and manufacturing technique. A preferred material is 6061-T6 high strength aluminum alloy initially extruded as a preform with depending side walls of given thickness and with converging spring elements of reduced wall thickness. After extrusion is completed, the spring elements are rolled inwardly toward the connector cavity as shown in Fig. 4. When a connector is installed, the set screw presses conductor 23 against the spring elements urging them outwardly as shown in Fig. 5. The spring elements have their extremities enter the conductor cavity defining a gap therebetween and the spring elements are adapted to move out of the cavity closing the gap when the conductor is secured in place providing visible means that suitable torque has been applied. The spring elements provide flexibility in the connection which can absorb vibrations or oscillations induced by wind conditions or conductor disturbances in the vicinity of the connector installation.

[0020] The principles of the present invention are also applicable to a secondary junction 30 with resilient spring contact shown in Figs. 4-6. The secondary junction is in the form of a unitary junction and includes a plurality of conductor cavities 32 as in the case of the embodiment of Figs. 4-6. As shown, the junction is preferably extruded and comprises an elongated crown portion 34 with exterior side walls 36 depending from opposite sides of the crown. Spring elements 38 project inwardly from the lower end of exterior side walls. A plurality of interior side walls 40 depend from the crown and have oppositely directed spring elements 42. The result is a plurality of cavities 32 defined by crown, adjacent side walls, and confronting spring elements. When extruded there is a gap G between spring elements in order to support mandrel cores for forming the conductor cavities. After the extrusion is complete, the gap can be closed by a secondary rolling operation.

[0021] The crown portion of the junction is fitted with a plurality of set screws 44, one for each conductor cavity.

[0022] In the course of securing a conductor within the junction cavity, the set screw will compress the conductor and rotate each of the spring fingers slightly in a downward direction bringing the spring tips in position adjacent to each other, closing the gap therebetween that existing prior to conductor installation as shown in Fig. 9. In this way, the operator has visual indication that proper contact force has been established between the set screw and the conductor. As also shown in Fig. 6, the inner surface of the spring fingers may be knurled or scored for improved contact between junction and cable.

[0023] Fig. 7 illustrates a modification of the present design in which a spring section 50 is formed as thin wall section in the downwardly depending sidewall 52 between adjacent junction cavities 54. The modified secondary junction connector includes a crown portion 56 and a closed base portion 58 interconnected by spring sections defining the laterally confined, open-ended conductor cavity 54. The spring sections 50 are of reduced wall thickness and yield or stretch vertically to accommodate vibration or movement of a conductor secured in the connector by means of set screws.

Claims

1. A device for connecting electrical conductors having an elongated crown portion (14, 34) with downwardly depending side walls (16, 36), the side walls (16) terminating in spring elements (18, 38, 42) which converge toward each other to define a cavity in the connector for receiving conductors (23), the ends of the spring elements (18, 38, 42) having a spring action acquired by being rolled inwardly toward the conductor cavity during manufacture, means (24, 44) for pressing conductors located in the cavity against the spring elements (18, 38, 42) to rotate the spring elements slightly in a downward direction and outwardly from the cavity bringing their tips adjacent each other thereby establishing spring action between the device and the conductors so that the connection is capable of enduring vibrational and other moving disturbances and providing visual indication that proper contact force has been established for securing the conductors (23) in the cavity.

2. A device as defined in claim 1 which includes a slot (26) in at least one of the side walls (16) for receiving a lever to allow the appropriate torque to be applied to the conductor pressing means (24, 44).

3. A device as defined in claim 1 which is formed of high strength aluminum alloy.

4. A connector for electrical conductors having an elongated crown portion (14, 34) formed of high strength aluminum alloy with integral downwardly depending side walls (16, 36), the side walls terminating in spring elements (18, 38, 42) which converge toward each other to define a wedge-shaped cavity within the connector for receiving conductor (23) through open ends of the device, the ends of the spring elements (18, 38, 42) being rolled inwardly toward the conductor cavity during manufacture to acquire their spring action, means (24, 44) for pressing conductors located in the cavity against the spring elements (18, 38, 42) urging the spring elements outwardly from the cavity bringing their tips adjacent each other thereby establishing flexible spring action between the device and the conductors in the cavity for absorbing vibrations or oscillations induced by wind conditions or conductor disturbances in the vicinity of the connector installation.

5. A connector as defined in claim 4, which includes a slot (26) in each of the side walls for receiving a lever to allow the appropriate torque to be applied to the conductor pressing means (24, 44).

6. A device as defined in claim 4, which is an extrusion of high strength aluminum alloy.

7. A device as defined in claim 4 in which the pressing means (24, 44) comprises a set screw passing through the crown (14, 34) into the cavity.

8. A device for connecting electrical conductors having an elongated crown portion (56) with downwardly depending side walls (52) and a closed base portion (54, 58) defining a cavity in the connector for receiving conductors (23), the side walls (52) having spring sections (50) formed by thin wall sections which yield vertically to accommodate vibration or movement of a conductor secured in the cavity so that the connection is capable of enduring vibrational and other moving disturbances, and means (59) for securing conductors in the cavity.

Drawing