US2695990A

US2695990A - Electrical connector

Info

Publication number: US2695990A
Application number: US300373A
Authority: US
Inventors: Wellington B Sullivan
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-07-23
Filing date: 1952-07-23
Publication date: 1954-11-30
Anticipated expiration: 1971-11-30

Description

Nov. 30, 1954 w. B. SULLIVAN 2,695,990

ELECTRICAL CONNECTOR Filed July 25, 1952 INVENTOR WELLINGTON 6. 5044 m4 BY 9 WW ATTORNEY-5 United States Patent ELECTRHCAL CUNNECTQR Wellington B. Eiullivan, Washington, D. C.

Application July 23, 1952, Serial No. 300,373

13 Claims. (Cl. 339--253) This invention relates to connectors for wires or cables and more particularly to a connector for connecting electrical conductors.

Many types of devices for connecting electrical conductors have heretofore been proposed, and for the most part, such connectors have been constructed as screwthreaded clamps. The use of such clamps, however, offers several objections such as expense of manufacture, difiiculty of installation and the inability of the clamp to maintain a predetermined contact pressure over a wide range of temperatures. This latter objection is particularly serious since it has been found in practice that when low temperature conditions are encountered, the conductor materials may have been subjected to such a high initial mechanical pressure as to cause the materials to cold flow and result in a relaxation of the joint and a consequent loss in conductivity. Such action will be readily understood when it is recalled that the clamp is composed of rigid screw-threaded parts which are tightly set up by the mechanic making the connection. It is quite impossible to accurately gauge the degree of mechanical pressure in such joints under the varying conditions encountered in practice so as to secure the requisite contact pressure and still avoid the disadvantages of metal cold flow and subsequent relaxation or decay of pressure throughout the life of the connection. While many attempts have been made to avoid the foregoing objections, none of them have presented a satisfactory solution.

It is accordingly a principal object of the present invention to provide a novel electrical connector which is so constructed and arranged as to overcome the objections and disadvantages referred to above.

Another object of the invention is to provide in an electrical connector, a novel but simplified construction wherein a predetermined contact pressure will always be obtained when the connector is installed and wherein such pressure will be maintained throughout the life of the connector, thus avoiding all possibility of relaxation of the contact pressure and the problems resulting therefrom.

Still another object is to provide a connector of the foregoing type wherein the contact pressure in the joint or connection may be preselected in a range to obtain a low resistance contact of adequate mechanical strength, while at the same time avoiding cold flow of the conductor metals.

Another object resides in a novel and relatively simplified construction which is capable of rapid installation without the use of complicated and expensive tools, the arrangement being such that the aforesaid predetermined contact pressure cannot be exceeded but will always be adequate.

Still another object is to provide an electrical connector having in addition to the foregoing features, the highly desirable advantage of avoiding corrosion when used to connect conductors made of different metals wherein bridging of the metals by moisture would usually cause corrosion.

A still further object is to provide a highly effective electrical connector which is capable of manufacture at a relatively low cost, which avoids the use of screwthreaded parts, and which when installed, maintains the contact pressure in the connection throughout the life thereof and regardless of wide variations in temperature to which the connector may be subjected in practice.

Other objects and novel features of the invention will appear more fully hereinafter from a consideration of 2,695,990 Patented Nov. 30, 1954 and the following detailed description when taken in connection with the accompanying drawing. It is to be expressly understood however, that the drawing is employed for purposes of illustration only and is not to be taken as a definition of the limits of the invention, reference being had for for this purpose to the appended claims.

In the drawing, wherein similar reference characters refer to similar parts throughout the several views:

Fig. 1 is perspective view of a connector embodying the feature of the invention and illustrating one form thereof for mechanically connecting a pair of electrical conductors;

Fig. 2 is an axial sectional View of the connector of Fig. 1 prior to the collapsing of the crimped tension member;

Fig. 3 is an end view of the connector of Fig. 2;

Fig. 4 is a view similar to Fig. 2 but illustrating the position of the parts when the tension member has been collapsed to complete the connection between the conductors;

Fig. 5 is an end view of the connector of Fig. 4;

Fig. 6 is a partial plan view of a modified form of tension member prior to crimping and installation thereof;

Fig. 7 is an end view of a connector similar to Fig. 1 but illustrating the tension member of Fig. 6 installed therein, and

Fig. 8 is a modified form of connector for electrically connecting a pair of conductors formed of different metals.

In its broad aspect, the present invention provides an electrical connector wherein predetermined contact pressures are developed over a sufficient conductor area to obtain a connection having a high mechanical strength while avoiding any relaxation thereof due to cold flow of the conductor metal.

The invention in a more specific aspect comprises a U-shaped sheet metal body member having one or more corrugations in its side walls and wherein the latter terminate at their free ends in a pair of parallel tracks. The conductor means are positioned between the side walls in contact with the bottom of the body member and a crimped metal tension member is inserted in the space between the side walls, the tracks and the conductor means, the folds of the tension member having a length greater than the space between the tracks and the conducting means. Upon subsequent collapse of the folds of the tension member, by a suitable tool of plier design, the successive folds are brought into contact with each other and the side walls are stretched and tensioned, this action being obtained by the aforesaid corrugations. Hence, upon assembly of the connector, a predetermined contact pressure is always developed and such pressure is such as to provide a strong mechanical connection with consequent low resistance, while at the same time being less than 1that which would cause cold flow of the conductor meta Referring more particularly to Figs. 1-5 of the drawing, the present invention is illustrated therein as embodying an electrical connector of the type adapted to mechanically and electrically connect a plurality of conductor means, such as a tap conductor 10 and a line conductor 12, the connector including a U-shaped body member 14 having an arcuate portion 16, for receiving the conductor means, and a pair of spaced apart and

parallel side walls

18 and 20. Preferably, the body member 14 is formed of sheet metal of a character which will not cause corrosion with the metal of the conductor means, and as shown, the free ends of the

walls

18 and 20 are respectively folded inwardly to provide a pair of opposed projections or

tracks

22 and 24 which are parallel with each other and parallel with the axis of the conductor means 10 and 12. Such tracks may be spaced apart a distance equal to the diameter of the largest conductor to be accommodated by the connector so that in placing the connector into position, as shown in Figs. 1 and 3, for example, it will not be necessary to spring the

side walls

18 and 20 apart,

.which might cause an undesirable deformation in said pressure will be maintained throughout the life of the connector. Such pressure will be selected to obtain a firm and satisfactory mechanical and electrical connection while being of a sufficiently low value as to avoid any possibility of cold flow of the conductor metal which would otherwise result in a relaxation of the contact pressure and a wholly unsatisfactory connection.

In order to develop the aforesaid predetermined contact pressure, the

side walls

18 and 20 are respectively provided with one or more corrugations 26 which are arranged parallel with the conductor axes, and which provide a predetermined degree of resilience in said walls, the latter being capable of being stretched a preselected amount, by means to be hereinafter described, in order to develop the aforesaid predetermined contact pressure when the connector is installed.

A novel arrangement is provided by the invention by which the body member 14 is installed in relation to the

conductors

10 and 12 as to secure the aforementioned predetermined contact pressure. As shown, Figs. 15, such arrangement comprises a crimped tension member 27 which is preferably formed of sheet metal of a character which will not cause corrosion with the conductor metals and which is bent in the form of an accordion pleated element having a plurality of oppositely directed and angularly related folds 28, the angle between the folds beingof the order of 45 to 60. From Fig. 2, it w ll be readily observed that the tension strip 27 is formed in two separated

portions

29 and 30 joined by a stralght portion 31, this construction being preferable for ease in assembly. As shown, the portion 31 is broken away to indicate that it may be longer or shorter than that illustrated. It will also be seen that the length of each of the folds 28 is greater than the distance between the conductor 10 and the

tracks

22 and 24, and that a greater or less number of folds may be employed than the number illustrated.

While Fig. 2 illustrates the tension member 27 as comprising two

portions

29 and 30, it will be understood that if desired, the said member may be formed of a single pleated element or may comprise two or more portions connected by straight portions like the portlon 31. Thus, in a connector for small conductors, a single pleated element comprising a plurality of folds 28 may be sufficient to obtain the aforesaid tensioning of the

side walls

18 and 20 while engaging the conductor 10 and the

tracks

22 and 24 throughout sufiicient axial extent as to provide a firm and rigid connection. In other cases where the connector is designed for larger conductors, two or more of the pleated sections may be found desirable. In any event, the invention is not limited to the number of folds nor the number of portions which may be utilized.

In the assembly of the connector, as illustrated in Figs. 2 and 4, the parts are associated in the manner illustrated in Fig. 2 wherein the first portion 29 of the tension member 27 is positioned between the

arms

18 and 20 with the lower edges of the folds 28 contacting the

tracks

22 and 24 and with the side edges thereof contacting portions of the

side walls

18 and 20 as shown at 32 and 34 in Fig. 3. The member 27 is thus frictionally held in position prior to collapsing of the folds thereof in the manner shown in Figs. 4 and 5, and While the top edges of the folds 28 are illustrated as being in contact with the conductor 10, in Fig. 2, it will be understood that such initial contact will be determined, for a particular size of connector, by the diameters of the conductors and the angularity of the folds 28. It is contemplated that the parts will be such that a connector of a particular size may be used to obtain a satisfactory connection between conductors which differ in size as well as those which are of the same size.

After the parts are positioned as shown in Figs. 2 and 3, a suitable tool of the plier type is inserted between the

separated tracks

22 and 24 and the folds 28 of the first portion 29 of the tension member 27 are collapsed to the position shown in Fig. 4. Such action causes the second portion 30 to be drawn into the space between the

arms

18 and 20, following which the folds 28 of the second portion 30 are collapsed in the same manner. The installed connector is shown in Figs. 4 and and therefrom, it will be readily seen that as the folds 28 are moved to the vertical position, the

side walls

18 and 20 between the conductor and the

tracks

22, 24 are stretched and elongated, this action being permitted by reason of the corrugations 26. Such stretching of the side walls will secure a predetermined contact pressure between the

conductors

10 and 12, which will always be the same and which is not due to the guesswork or skill of a particular mechanic as in the case of screw-threaded connectors.

From the foregoing, it will be understood that the tensioning of the connector is due to the corrugations 26 in the

side walls

18 and 20 and in the movement of the folds 28 of the tension member 27 from the angular positions shown in Figs. 2 and 4 to the vertical or upright positions illustrated in Figs. 4 and 5 where adjacent folds are brought into contact with each other and arranged at to the axis of the conducting means. In assembling the parts, it is seen that the folds, when erected, function as wedge members or compression struts for tensioning and stretching the side walls 18 and 20 a predetermined amount as determined by the particular shape of the corrugations 26. The connector thus has a built-in or latent tension of a predetermined character which is developed to the selected degree upon installation, and such tension may be readily chosen and the connector parts so constructed that the final contact pressures will be well within the limitations of metal cold fiow. A tight and satisfactory electrical connection is thus always assured.

Should there be any tendency during assembly and installation of the connector heretofore discussed for the free ends of the

side walls

18 and 20 to spread apart, the modified construction illustrated in Figs. 6 and 7 may be utilized. Therein, the tension member 40 is similar to the member 27 except that alternate folds 42 thereof are provided at their lower edges with projections or ears 44 which extend downwardly and between the inner surfaces of the

respective side walls

18 and 20 and the inturned free ends thereof as shown in Fig. 7. Preferably, these ears 44, see Fig. 6, are formed integrally with the tension member 40, being cut from alternate folds 42 along the

cut lines

46, 48 and 50. Thereafter, the ears 44 are bent outwardly with respect to the plane of the member 40 and are then twisted through an angle of substantially 90 so as to be closely adjacent the edge of the tension member 40, as shown at the right hand portion of Fig. 6. Thus when the latter is crimped to form the folds 42, in a manner similar to the folds 28 of tension member 27 of Fig. 2, the ears 44 will project downwardly in the manner shown in Fig. 7.

Fig.8 discloses a modified form of connector which embodies all of the features heretofore described in connection with the connector of Figs. l-7, and is especially adapted for electrically connecting a pair of electrical conductors made of different metals where corrosion problems might be present. For example, in connecting steel or aluminum conductors to copper conductors it has been found that moisture bridging the unlike conductors acts as an electrolyte and promotes galvanic corrosiqn between the conductors. The embodiment shown 1n Fig. 8 avoids such corrosion in a relatively simple but highly effective manner.

As shown, the connector 52 of Fig. 8 may be adapted to connect an aluminum conductor 10 with a copper conductor 12, for example, in which case, a single strip of sheet metal formed in accordance with the well known claddlng process and having one surface of aluminum and the opposite surface of copper, is bent .to form a pair of integral U-shaped

connector body members

54 and 56, these bemg opposed to each other and slightly offset, as illustrated. It will be understood that during formation of the

body members

54 and 56, the cladded metal strip is bent so that the interior surface of the member 54 will be aluminum, for presentation to the aluminum conductor 10 and that the interior surface of the member 56 will be copper, for presentation to the copper conductor 12. Th s arrangement automatically results when the strip-materlal is folded in the manner illustrated. In all other respects, the body members are similar to the body member 14 of Figs. l-7.

Installation of the connector 52 is similar to the first form of the invention except that the

body members

54 and 56 are respectively secured to a single conductor only. For example, after the

conductors

10 and 12 have been associated with the arcuate portions of the

respective body members

54 and 56, it is only necessary to insert the crimped tension members 27 and collapse the folds thereof in the same manner as has been described heretofore. The same tensioning features and the same stretching of the side walls of the

body members

54 and 56 will occur as the folds of the tension members 27 are erected, by reason of the incorporation of the side wall corrugations 26. it is to be pointed out however, that the tension member associated with the conductor will be made of aluminum while the tension member used with the conductor 12 will be made of copper in the example chosen. Thus, with the construction proposed, the aluminum conductor it) will only be contacted by aluminum surfaces while the copper conductor 12 will only be contacted by copper surfaces, thus avoiding any possibility of corrosion between unlike metals.

It will be understood that in the description of Fig. 8 the use of aluminum and copper conductors has been given by way of example only and that this form of the invention may be employed for electrically connecting any two conductors formed of metals subject to corrosion. In such other cases, the connector is formed of the proper cladded metals and is so arranged that the interior surfaces of the body members are like the metal of the respective conductors. Also, the respective tension members are of a metal which is similar to or which will not promote corrosion with respect to the conductor with which it is associated.

It will be readily seen from the foregoing that the present invention provides an unusually efficient electrical connector which may be used to connect a plurality of engaged electrical conductors or to electrically connect a pair of spaced conductors of dissimilar metals, the construction in each case being such that a predetermined contact pressure will always be obtained when the connection is made, and will be maintained without the danger of cold flow of the conductor metals. In addition to the foregoing, the connector is of a relatively simple construction and is capable of economical manufacture by the use of well known stamping or extrusion methods. An added advantage resides in the simplicity of installactiion without requiring tools of complicated and costly esign.

While the invention has been illustrated and described herein with considerable particularity, it will be understood by those skilled in the art that the invention is not limited to the forms shown but is capable of a variety of expressions without departing from the spirit of the invention. For example, while reference has been made herein to the formation of the connector from sheet metal, it is apparent that in the form shown in Figs. 17, plastic materials composed of plastic alone or combined or reinforced with metal may be utilized providing such materials possess the necessary characteristics to provide the advantages set forth herein. Other changes may be made within the scope of the invention as defined in, the appended claims.

What is claimed is:

l. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion and a pair of spaced apart parallel sides, the conducting means being positioned between said sides and contacting the arcuate portion of said body member, a proj ection carried by each side adjacent the free edges thereof, and means for frictionally securing the body member to the conducting means comprising a crimped tension member having the folds thereof collapsed to bring adjacent folds into contact with each other and with the opposite edges of the folds respectively engaging the projections and the conducting means.

2. in a connector for electrical conducting means, the combination of a U-shaped body member having sides lying substantially parallel to each other, each of said sides being provided with inturned ends providing a pair of tracks, and an accordion pleated strip having its successive pleats collapsed and engaging each other to tension said sides, the edges of the pleats at one side of the strip engaging said tracks and the conducting means being confined between the strip and the arcuate portion of the body member.

3. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of resilient side walls arranged parallel with each other, each of said side walls having an inturned end to provide a track, and a tension member comprising a metal strip bent to form a plurality of oppositely directed folds interposed between the tracks and the conducting means, said folds being collapsed to bring adjacent folds into contact with each other to tension said resilient side walls.

4. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of resilient side walls each having a corrugation therein extending parallel with the axis of the conducting means, and said walls being respectively provided adjacent their free ends with an inwardly directed projection forming a pair of parallel tracks, and means interposed between said tracks and the conducting means to tension said side walls and firmly grip said conducting means comprising, a crimped tension member having the folds thereof collapsed to bring adjacent folds into contact with each other and with the opposite edges of the folds respectively engaging the projections and the conducting means.

5. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of parallel, spaced apart side walls, each wall provided with a corrugation extending parallel with the axis of the conducting means, and said walls being provided adjacent their free ends with an inwardly directed projection forming a pair of parallel tracks, and a tension strip bent to form a plurality of oppositely directed and angularly related folds, the length of said angularly related folds being greater than the space between the conducting -means and the tracks, said strip being interposed between the tracks and the conducting means with the folds thereof collapsed to...bring adjacent folds into parallel and contacting relationship to stretch said corrugations and tension the body member and conducting means into contact with each other to a predetermined degree.

6. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of parallel, spaced apart side walls, each Wall provided with a corrugation extending parallel with the axis of the conducting means, and said walls being rovided adjacent their free ends with an inwardly directed projection forming a pair of parallel tracks, and means for frictionally securing the body member to the conducting means comprising, wedge means interposed between the tracks and the conducting means and with opposite sides of the wedge means respectively engaging the opposed inner surfaces of said corrugations to stretch said corrugations and tension the body member and conducting means into contact with each other to a predetermined degree.

7. in a connector for electrical conducting means, the combination of a U-shaped body member having sides lying substantially parallel to each other, each of said sides being provided with inturned ends providing a pair of tracks parallel with the axis of the conducting means, and a tension strip provided with a pair of separated accordion pleated portions, the successive pleats of each portion being collapsed into engagement with each other to tension said sides, the edges of the pleats at one side of the strip engaging said tracks and the conducting means being confined between the strip and the arcuate portion of the body member.

8. A connector for electrical conducting means, comprising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of resilient side Walls arranged parallel with each other, each of said side walls having an inturned end forming a track parallel with the axis of the conducting means, and a tension member comprising a metal strip bent to form a pair of separated portions each of which comprises a plurality of oppositely directed folds interposed between the tracks and the conducting means, the folds of each of said portions being collapsed to bring adjacent folds into parallel and contacting relationship with each other to tension said side walls.

9. A connector for electrical conducting means, com prising a U-shaped body member having an arcuate portion for receiving said conducting means and a pair of parallel, spaced apart side walls, each wall provided with at least one corrugation extending parallel with the axis of the conducting means, and said walls being provided adjacent their free ends with an inwardly directed projection forming a pair of parallel tracks, said tracks being parallel with the axis of the conducting means, and a tension strip bent to form a pair of separated portions each of which comprises oppositely directed and angularly related folds, the length of said angularly related folds being greater than the space between the conducting means and the tracks, said portions being interposed between the tracks and the conducting means with the folds of each portion collapsed to bring adjacent folds of each portion into parallel and contacting relationship to stretch said corrugations and tension the body member and conducting means into contact with each other to a predetermined degree.

10. A connector for electrically connecting a pair of conductors of different metals of the type wherein bridging the conductors by moisture causes corrosion of the conductors, comprising a sheet metal strip formed of two cladded metals respectively similar to the metals of said conductors, said strip being formed to provide a pair of opposed and offset U-shaped body members for respectively receiving the conductors, the interior surface of one body member being of a metal like the conductor which it receives, and the interrior surface of the other body member being of a metal like the conductor which it receives, each of said body members having a pair of side walls provided with opposed tracks, and wedge members respectively interposed between the tracks and the conductors within the body members, said wedge members being respectively of a metal like the conductors with which they contact.

11. A connector for electrically connecting a pair of conductors of different metals of the type wherein bridging of the conductors by moisture causes corrosion of the conductors, comprising a sheet metal strip formed of two cladded metals respectively similar to the metals of said conductors, said strip being formed to provide a pair of opposed and offset U-shaped body members for respectively receiving the conductors, the interior surface of one body member being of a metal like the conductor which it receives, and the interior surface of the other body member being of a metal like the conductor which it receives, each of said body members having a pair of parallel side walls each of which is provided with a corrugation, each side wall terminating in an inwardly directed fold forming a track, and a pair of tension strips each bent to form a plurality of oppositely directed and angularly related folds, the length of said folds of each strip being greater than the space between the respective conductors and the tracks of each body member, said strips being respectively interposed between the tracks and the conductors of the respective body members with the folds thereof collapsed to bring adjacent folds into parallel and contacting relationship to stretch said corrugations and tension the respective body members into contact with the conductors received therein, said tension strips being respectively of a metal like the conductors with which they contact.

12. A connector for a pair of electrical conductors, comprising a U-shaped body member for receiving said conductors in the arcuate portion thereof one above the other, said member having a pair of parallel, spaced apart side walls, each wall provided with a corrugation extending parallel with the axis of the conductors, and said walls being provided at their free ends with an inturned portion forming a pair of parallel tracks, and a tension strip bent to form a plurality of oppositely directed and angularly related folds, the length of said folds being greater than the space between the conducting means and the tracks, said strip being interposed between the tracks and the conducting means with the folds thereof collapsed to bring adjacent folds into parallel and contacting relationship to, the sides of said strip engaging the inner surfaces of said side walls.

13. A connector as set forth in claim 12 wherein some of said folds are provided with projections positioned between said walls and said inturned portions to prevent the walls from spreading apart as the folds of said strip are collapsed.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,431,176 Ogden Oct. 10, 1922 1,531,816 Russell Mar. 31, 1925 1,741,804 .Zilliox Dec. 31, 1929 2,106,724 Cope Feb. 1, 1938 2,603,680 Snyder July 15, 1952 FOREIGN PATENTS Number Country Date 733,024 Germany Mar. 17, 1943