US2547080A

US2547080A - Spring clamp connector

Info

Publication number: US2547080A
Application number: US39699A
Authority: US
Inventors: Edward S Hebeler
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-07-20
Filing date: 1948-07-20
Publication date: 1951-04-03
Anticipated expiration: 1968-04-03

Description

April 3 1951 E. s. HEBELER 2,547,080

SPRING CLAMP CONNECTOR Filed July 20, 1948 6%@ af MOR Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE SPRING CLAMP CONNECTOR Edward s. Hebeler, Williamsville, N. Y. Application July 20, 1948, Serial N0. 39,699

6 Claims. (Cl. 173-269) This invention relates to improvements in connections between electrical conducting cables of the type including many relatively small wires to provide ilexibility of the cable, and a connector therefor.

Cables of the type made of numerous small diameter wires, in such a manner that they will be readily exible, are commonly used in connection with Welding and other apparatus in which the cable is flexed, twisted and bent during the use of the apparatus, and diculty has been experienced in the past in making a good connection between an end of a cable of this type and a connector, unless the end of the cable is soldered to the connector., This, however, has been found objectionable, for the reason that the solder tends to run along the cable and to render that part of the cable in which the wires are connected by solder stii. Consequently, at the end of the solder, the thin wires will bend to a greater extent than at those parts of the cable which are free from solder, thus causing rapid breaking of the wires at the ends of the soldered parts of the cable, because the small wires will be subjected to the maximum bending at the portion thereof adjacent to the portion of the cable rendered rigid by the solder.

Unsoldered cable ends are very difficult to hold in clamped tight and rigid electrical connection with a connector by means of the usual clamping screws or bolts, since even if such screws or bolts are initially tight and form a good electrical connection, it has been found that such connections become loosened during the use of the connection, so that eventually there is not sufficient pressure between the cable and the connector. This re duction in pressure results in a poor electrical connection and in heating of the connector and the cable end and the heating in turn results in forming an oxide on the surface of the wires or connector which in turn further increases the resistance of the connection and results in further heating of the same, so that eventually the connection becomes excessively hot and fails to transmit the required amount of current from the cable to the connector. In some cases, the connector becomes too hot to be handled and may constitute a re hazard.

I have found that the reason for this rapid heating of the connection between the cable and the connector is due to the shifting of Wires of the cable at the point or points where the pressure is applied, due to the fact that the connector, when used in connection with welding or other operations is moved, turned and twisted. This shifting of the Wires of the cable gradually reduces the pressure urging the cable into contact with the terminal, so that even if a very good electrical connection is originally made by clamping the screws or bolts up tightly, yet as the wires Y 2 of the cable shift relatively to each other, this pressure gradually decreases, thus resulting ina gradually increasing resistance and consequent heating of the connection.

One of the objects of this invention is to provide an electrical connection between a cable end and a connector by means of which a constant pressure is exerted on the cable, pressing the same toward the connector, which pressure is maintained in spite of the shifting of the wires of the cable.

A further object of this invention is to provide a connection of this type in which a spring is employed which exerts a substantially constant pressure urging the cable into contact with the connector at all times, regardless of the shifting of the wires of the cable relatively to each other. A further object of this invention is to provide a connection between a cable and connector which also serves to prevent the pulling of the cable out of the connector. A further object is to provide a connection which is so constructed that any pulling of the cable relatively to the connector in a direction to disengage the same from the connector will result in increased tension and gripping of the cable to the connector.

Other objects and advantages of this invention will vappear from the following description and claims.

In the accompanying drawings, which illustrate by way of example certain embodiments of this invention:

Fig. 1 is a side elevation of a holder for a welding rod to which a cable connection embodying this invention may be applied.

Fig. 2 is a fragmentary, longitudinal, central, sectional view thereof.

Fig. 3 is a transverse section thereof, on line 3-3, Fig. 2.

Fig. 4 is a fragmentary, top plan view thereof.

Fig. 5 is a fragmentary, longitudinal, central sectional elevation of a connection of modified construction.

Fig. 6 is a transverse sectional view thereof, on line 6 6, Fig. 5. Y

Fig. '7 is a perspective view of a spring which may be employed to form a connection between the cable and the connector.

Fig. 8 is a fragmentary, longitudinal, central, sectional elevation of a connection of another modified form.

Fig. 9 is a transverse sectional elevation thereof, on line 9 9, Fig. 8.

Fig. 10 is a transverse sectional view of a connector showing a connection of modiiied construction.

Fig. 11 is a perspective view of the combined spring and pressure pad shown in Fig. 10, on an ,enlarged scale.

I have in Fig. 1 illustrated a holder for a Weld-= ing rod to which a flexible cable may be connected by means of connections embodying my invention. It will be understood, however, that it is not intended thereby to limit this invention for use with welding rod. holders, since it will be obvious that the improvements embodying this invention may be applicable to any connection between a flexible cable and a rigid connector therefor.

In Fig. 1, the welding rod holder includes: a pair of gripping members I and II which are pivotally connected, for example, by means' of a pivot I2. The gripping member II has a handle I4 arranged thereon by means of which the pivoted gripping member II. may be swung about thepivot I2 to enable a welding rod I5 to be gripped in any of the, notches or recesses I6 in the jaws of the gripping member. The rod' is securely held in the jaws by means of a compression spring I'Iy acting on the two gripping members Il! and II in a direction to close the jaws.

The rod gripping member I0 is provided'. at the rear thereof with a connector, indicated in general by the reference character I8, for connection with a flexible cable,I9. A sleeve 20 of insulating material is usually slid over the connector' so that, the operator, in using the device, grips the insulating handle portion Ill and the sleeve 2S to avoid contact with current-carrying metal parts of the device.

The connector I8 may be of any usual or suitable construction, and in the form illustrated by Way of example, it, is of. substantially hollow, cylindrical or tubular form, the interior of the cylindrical portion having a substantially cylindrical aperture 22 of sufficient size to receive the bare wire portion 24 of the cable. A part of the cylindrical portion of the connector intermediate of the ends thereof is omitted or removed', thus forming a trough-shaped portion 25` and a cylindrical portion 26 at thel end of the connector, through which the Wire portion of an end of the cable may be passed to lie in the trough-shaped portion 25. In these connectors as heretofore constructed' suitable clamping means including screws, bolts or the like were employed for pressing the. wire portion of the cable into the lower or trough-shaped portion 25. of the cylindrical part of the connector.

In the use of an implement such as an electrode or rod holder of a welding apparatus, the connection between the cable I9 and the connector I8 is subject to substantially continuous movement of the connector I8 during the time that the operator uses the welding rod holder. The welding operation requires bending, twisting, turning and other movements of the welding rod holder, and all of these movements are transmitted to the. end of the cable which is connected with the connector. It is, therefore, necessary that these cables have a high degree of flexibility and, consequently, they are made of a large number of fine or small gage current-conducting wires. Usually the connection between the cable and the connector includes screws or bolts which are tightened to apply pressure to the, cable for at- 'caching the same to the connector and, as heretofore stated, the repeated movements of the rod holder results in the fine Wires of the cable shifting and readjusting themselves at the point or points at which the clamping pressure is applied, so that the pressure acting on the cable'is gradually reduced due to lateral slipping of the wires of the'cable, thereby producing a poor connection between the cable and connector, which results in the heating of the connector and adjacent parts of the cable, which in turn results in the covering of. the. wires and connector with a nlm of oxide which makes the. electrical connection worse.

In order to overcome the difficulties heretofore experienced with clamping devices for securing the cables to connectors, I have found that the heating of the cables and the connectors can be greatly reduced by providing a yielding or spring memberv for exerting a resilient force against a portion of the cable within the connector. By means of this construction, if the wires of the cable, during the continued use or moving of the connector, become shifted or readjust themselves, this shifting or readjusting will be followed with a corresponding movement of' the yielding or spring member, so that substantially the same force will be exerted on the cable as was exerted on it before the shifting or adjusting of the wires of the cable took place.

In order to accomplish this result, I have provided in Figs. 2 to 4, a leaf spring 3G which is curved to follow approximately the contour of the outer surface of the cylindrical portion of the connector and which has a plurality of spring arms 3S extending therefrom over the troughshaped part 25 of the connector, two such arms being shown in the construction illustrated. The outer ends of the arms have a portion 32 bent toward the axis of the connector I8, and a pressure pad or intermediate pressure transmitting member 33 is arranged between the bare portion 2li of the cable and the downwardly extending portions 32 of the arms of the spring. This intermediate member may be provided witha lower surface formed to contact with the wires of the cable and a groove 35 in the upper surface in which the extensions 3l of the armsA may seat. This spring member may be sprung around the trough portion of the connector, whereupon the arms 3l will exert a force against the pad or intermediate member 33, urging the same against the wires of the cable to press the same into the trough-shaped part 25'. By means of this con'- struction, the shifting of the wires of the cable relatively to each other Will not result in any material reduction of pressure on the cable, since if the wires of the cable become more compacted or spread laterally under theintermediate member 33,v this member will be urged farther into the trough of the connector by means of the spring pressure of the arms 3l. j

One end of the intermediate member 33' may extend under the cylindrical portion 26 ofthe connector,r and this cylindrical portion also serves as a stop against which one of the arms SVI Vof the spring member may` bear to resist pulling of the cable out of the connector. The pad or intermediate member may also be of slightly tapering or wedge-shaped form with the end thereof of least height extending into the cylindricall portion 2t. Consequently, any pulling on the cable 24 will cause the wedge-shaped intermediate member 33 to enter farther into the cylindrical part 2S, thus causing this member to press more tightly against the cable, and thus form an improved electrical connection, supplementing the action of' the spring 30 and also gripping the cable more securely in the conjnector to resist removal of the same lengthwise therefrom. The wedging ofv the intermediate member 33 into the cylindrical part 26 exerts pressure against the part of the cable adjacent trough portion 25 of the connector.

mediate member 45. 'connector below the trough 25 may be provided to the smaller end of the wedge-shaped interl'mediate member 33 and the spring arms 3| serve to apply adequate pressure to the other end of the intermediate member 33 to assure a good electrical connection between the cable and the connection throughout the length of the wedgeshaped intermediate member 33. The wedging action of the cylindrical part supplements the pressure applied to the cable, but the spring arms 3| alone are capable of pressing the cable against the connector with sufficient force *to ensure a good electrical connection.

A In the modified construction shown in Figs. 5 fto 7, the connector is similar to the one shown lin Figs. 1 to 4, except that the annular or cylin- Idrical end portion 3S is provided on the upper portion of its inner surface with a tapered or inclined face 31. A pressure pad or interme-A 'diate member 45 of somewhat different construction is employed, that shown having at one vend thereof a wedge-shaped portion 4| adapted to cooperate with the inner tapered surface 31 'of the cylindrical part 35. The pressure pad or intermediate part 45 is urged into engagement with the wire portion 24 of the cable by means `hof a wire spring member having a U-shaped portion 43 which engages the underface of the The ends of the legs of the U-shaped member are curved :upwardly as shown at 44 and terminate in down- 51' wardly extending end portions 45 which are Aadapted to enter into grooves or recesses formed in vthe upper face of the pressure pad or inter- The outer surface of the with a series of notches 41 into which the legs of the U-shaped portion 43 may enter to hold this part of the spring against movement lengthwise of the connector I8.

',In'applying this spring to the pressure pad or intermediate member 45, this member is first forced to the right in Fig. 5, so that the wedge part 4| will be forced into the cylindrical part '36 of the connection, and the spring may then be applied to the pad or intermediate member 4U by inserting the ends 45 into the grooves or 'recesses in the upper face of the pad. The lowker U-shaped part 43 of the spring is then moved to the right in Fig. 5 as far as possible and en tered into two of the notches 41, so that the curved parts 44 of the spring' member will assume inclined positions, as shown by broken lines in Fig. 5. lThis spring will, consequently, serve the two-fold purpose of pressing the pressure pad or intermediate member 4G directly against the wire part of the cable to force the same into lthe trough 25, and the upper ends of the curved parts 44 of the spring will also have a tendency to assume vertical positions. Since the notches 41 prevent the lower U-shaped part of the spring from moving to the left in Fig. 5, it will be obvifous that the spring will, consequently, tend to urge the pad or intermediate member 45 to the right to retain the same in wedging relation to I.the cylindrical part 36.

In this construction, as well as that described in connection with Figs. 2 to 4, the spring member will provide a continuous force on the pres- -sure pad 'so that if the wires of the cable be- 'comeireadjusted or shifted laterally to occupy a smaller space vertically, the pad, because of the pressure oi` the spring, will follow up the wire part of the cable so that substantially the same ypressure will be applied thereto after reconnector 53.

adjustment of the wires ofthe cable asbefore the re-adjustment took place. :z

Figs. 8 and 9 show still another modified form of my invention, in which a connector also has a cylindrical portion 5| arranged between the end of the connector and the cutout portion of the same, and this cylindrical portion is provided with a tapered inner surface 52 similar to the surface 31 shown in Fig. 5. The wire portion 24 of the cable i9 is pressed into the trough 25 of the connector by means of a pressure pad or intermediate member 53. In this construction, the pressure pad or intermediate member 53 is pressedl into wedging relation with the cylindrical part 5| and into engagement with thewire part 24 of the cable by means of. a coil spring 55, one end of which enters a seaty or recess -56 formed on the pressure pad 53, the other end of which is seated in a recess 51 formedin the The upper face of the pressure member has the upper surface 55 thereof curved downwardly lengthwise thereof, which causes the coil spring 55 to assume a curved position when the ends thereof are arranged in the

seats

56 and 51. This upper surface is also trough-shaped to receive the intermediate portion of the spring 55. Consequently, the coil spring 55 exerts pressure lengthwise of the connector against the part of the pressure pad which is formed to be wedged into the inclined inner surface of the cylindrical part 5| of the connector. This pressure exerted by the coil spring also tends to cause the coil spring to .become bowed and thus exerta pressure against the upper face of the pressure pad or intermediate member, thus urging the same toward the wire part of the cable to press the same into the trough 25 of the connector. In this construction, it will also be obvious that readjustment of the wires of the cable relatively to each other will be followed by a movement' of the pressure pad toward the cable, due to the action of the spring 55, so that a loose connection between the wire portion of the cable and the connector is prevented. By urging the pressure a pad or intermediate member into wedging relation with the cylindrical part 5|, the spring further assures compression of the wire part of the cable adjacent to the cylindrical part 5| against the trough of the connector 5|). In the construction shown in Figs. 5 to 9, it will noted that the springs shown exert both transverse pressure on the intermediate member to 'force the cable into the trough of the connector, and lengthwise pressure against the intermediate member to produce a Wedging action of the cable against the connector. y

In the construction shown in Fig. l0, the connector shown is the same in construction as the oneshown in Figs. 1 to 4, including a troughshaped portion -25 and a cylindrical end portion 26. In this construction, the spring and the pressure pad or intermediate member are formed in one piece. The spring is in the form of a band or strip of spring metal having aA part 55 formed to extend partly around the outer surface of the trough portion 25 and a part 65 which extends over the open face of the trough portion. This latter part terminates in a part 51 which constitutes a pressure pad or intermediate member which is formed to engage the wire portion 24 of the cable and to press the same into the trough 25. This pressure pad portion 51 and the adjacent portions of the spring part 66 are preferably provided with a plurality of slits 68 which divide this part of the spring into aA plurality of fingers, each of which may engage a part of the cable independently of the other fingers. Preferably the ends of the fingers which formv the pressure pad are slightly inclined in such manner thatk the lower edge portions '[8 thereof grip they cable. In securing this spring on a connector, the higher edges 'H of the lingers of' the pad are arranged adjacent to the cylindrical. portion 26., so that if a pull is exerted on the. cable to pull the same from the connector, the lower edges of the pressure pad lingers will tend tob-ite into the cable and oppose such pull, and the spring itself will abut against the cylindrical portion 25 and will be held on the connector thereby.

It will be understood that various changes in the. details, materials, and arrangements oi parts which have been herein described and illustrated in; order to explain the nature of the invention. maybe made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. An electrical connection for a flexible current-carrying cable comprising a large number` of small wires, including a rigid connector having a hollow cylindrical portion at one end thereof through which the cable may extend and a trough-shaped portion adjacent thereto into which a part of said cable maybe laid lengthwise, an intermediate pressure-transmitting member overlying said trough-shaped part of said connector and having an end` portion thereof formed to extend into said cylindrical portion and to cooperate therewith to wedge said intermediate member against said cable, and a spring acting on said intermeditae member to force the same against the portion of the cable lying said trough-shaped part.

2. An electrical connection for a ilexible current-carrying cable comprising a large number of small wires, including a rigid connector havi-ng a trough-shaped part into which a part 0i said cable may be laid lengthwise, and a hollow cylindrical portion through which an end of a cable extends before entering said trough-shaped part, an intermediate pressure-transmitting member overlying said trough-shaped part of said connector and entering said hollow cylindrical portion of' said connector, and a resilient member acting on said intermediate member to urge the same against the cable to force the cable into said trough, said cylindrical member forming a stop which said resilient member may engage to resistv pulling said cable out of said connector.

- 3.. An electrical connection for a flexible current-carrying cable comprising a large number of small wires, including a rigid connector having ahollow cylindrical portion at one end thereof through which the cable may extend and a trough-shaped portion adjacent thereto into which a part of said cable may be laid. lengthwise an intermediate pressure-transmitting member overlying said trough-shaped part of said connector and having an end portion. thereof formed to extend into said cylindrical portion and to. cooperate therewith to. wedge said intermediate member against said cable, and a spring acting on said intermediate member to force the same .against the portion of the cable lying in said trough-shaped part, said spring. also exerting pressure on said intermediate member to. urge the same in` the direction of itsy length into wedging relation to said cylindrical portion of said connector.

4. An electrical connection for a. exible current-carrying cable comprising a large. number of small wires, including a rigid connector having a substantially cylindrical part at an end thereof and a trough-shaped part adjacent to said cylindrical part into which a part of said cable may be laid lengthwise alter passingl through said hollow cylindrical part, an intermediate member having one end thereof wedge-shaped and formed to enter said cylindrical part to wedge said cable therein, and ay coil compression spring having one end thereof engaging said connector and the other end engaging said intermediate.y member to force. thel same into wedging engagement with said cylindrical part and said connector, said coil spring being bowed to engage` another portion of said intermediate member to yield- -ingly urge the same toward said trough to compress said cable between said intermediate member and. said trough.

5. An electrical connection for a iiexible. current-carrying cable comprising a large number of small wires, including a rigid connector having a trough-shaped part into which a. part of said cable may be laid` lengthwise, and a hollow cylindrical portion through which an end of a cable extends before entering. said trough-shaped part, a yielding member exerting pressure on said cable in a direction to press. the same into said trough, an intermediate member interposed between said cable and said yielding member 'and having a tapering end portion extending into said cylindrical portion of said connector and serving to wedge said cable and intermediate member into L* said cylindrical portion when said cable is subjected to a pull in a direction to withdraw the end thereof from said connector.

6. An electrical connection for a flexible current-carrying cable comprising a large number of small wires, including a rigid connector haying a trough-shaped part into which a part of said cable may be laid lengthwise, a spring member extending partly around said connector and having a plurality of arms extending above said trough, and an intermediate member interposed between said spring arms and said cable, said spring arms acting on said intermediate member to press the same against said cable.

EDWARD S. HEBELEE.

REFERENCES CITED lThe following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date 1,099,034 Girard Jan. 2, 191.4 1,551,252 Johnson, Jr. Aug., 25, 1925 1,552,244 Thomas Sept. 1, 1925 1,860,262 Niemann May 24, 1932 2,198,193 Drachman et al. Apr.. 23, 1940 FOREIGN PATENTS Number Country Date 485,888 France. Feb. 15,1918 886,954 France Oct. 29, 1943