US3172180A - Wire gripping device - Google Patents

Description

F. P. BARlcl-:vlc ETAL 3,172,180

WIRE GRIPPING DEVICE:

Filed July 16, 1963 March 9, 1965 I I/ 5% l 43 37 Wyk/5%' United States Patent O 3,172,180 WIRE GRIPPING DEVICE Ferdinand P. Baricevic, Chicago, and James 3. Saul, La

Grange Park, lll., assignors to Reliable Electric Company, Franklin Park, Ill., a corporation oi illinois Filed July 16, 1963, Ser. No. 295,346 3 Claims. (Cl. 24-126) j The present invention relates to wire gripping devices such as line splices and deadends and is particularly applicable to line splices and deadends of the slidinr jaw type. These are sometimes installed manually, but frequently they are installed by hot stick technique, in which it is desirable to minimize the number of manipulative steps involved.

With the development of aluminum cable, it has been necessary to use a pilot cup in this type of wire gripping device in rorder to protect the jaws from the tangs of the strands. When aluminum cable is cut, it is suiciently soft so that a pronounced Itang will be provided for each strand. In inserting the cable between the jaws, the tangs will catch on the jaw and interfere with the smooth action of the device, resulting either in a chattering action or a relative longitudinal displacement of one jaw with respect to the others, or a canting of the whole jaw assembly. If the tang projects into the space between two jaws, it is very possible that the jaws cannot be contracted into gripping relationship. If the cable end passes through the jaw satisfactorily, then the possibility arises that the tang will catch on a Spring convolution in which event no gripping action can be developed.

It is for the foregoing reasons that a pilot cup has been proposed which serves as a nose or a shield for the cable end as it passes both through the jaws and the spring.

However, the use of the pilot cup in itself does not solve the problem of entry unless the pilot cup is considerably larger than the cable diameter; this, in turn, calls for a larger shell diameter than would otherwise be necessary, thus increasing the over all cost of the device. Such problems were not encountered with the relatively much harder copper cable for the reason that the ends of the jaws could be flared, thus facilitating the entry of the cable between the jaws with a minmum of manipulative steps, and the absence of a pronounced tang in the case of the harder copper cable did not require the use of a pilot cup.

' According to our invention, we provide a removable strand guide which is mounted on the end of the shell, and which has a funnel-shaped opening, the minimum diameter of which is less than the diameter of the pilot cup. The funnel shape of the guide thus serves to realign the strands of the cable with respect to the over all dimensions thereof including any tangs, and to center the cable end as realigned with respect to the pilot cup. Due to the fact that the opening is smaller than the cup diameter, any cable that passes through the opening will readily be received within the cup.

With respect to more pronounced tangs, the strand guide will function more in the nature of a go-no-go gauge, thus indicating immediately to the operator that the tangs are too large and that the cable end must be recut or otherwise reshaped.

The specic manipulative problem encountered, and which is solved by the use of our' strand guide, is that in order to insert the cable end into the cup, it is necessary to grip the cable end, perhaps a half inch from the end surface so as to compress the strands and permit entry thereof into the pilot cup, assuming that the tangs are not pronounced. As soon as initial entry has been effected, it is not possible to release the hot-stick clamp because then the cable would pull out of the cup; rather, it is necessary to apply a second hot-stick clamp perhaps "ice one-half inch behind the rst, then remove the rst clamp and push the cable in another half inch, and a succession of such short moves is required before it is possible to apply the clamp at a point several inches from the end of `the shell and give one long shove to push the cable through the cartridge and out of the outher end, in the case of a feed through deadend, and which ultimate relationship is required before the jaws are able to perform their required gripping function. A

Merely to perform the above operation manually, that is with the fingers, requires at least a minute due to the series of progressive short moves required, and by hot-stick technique several minutes may be consumed. When the tang is pronounced, the manipulation is more involved since it requires angular inclination of the cable with respect to the axis of the wire gripping device in order to get the tangs into the cup prior` to the cable end as a whole.

However, when the wire gripping device is provided with a guide according to our invention, the cable can be gripped several inches from the end, and a single movement will suce to cause the cable to pass through the guide and into the pilot cup, and cause subsequent release of the pilot cup and the initial feeding movement of the cable through to its home position in the case of a line splice, or to the yfeed-through position in the case of a deadend.

A second feature of our invention is the fact that after the guide has served its purpose it may be removed. According to this aspect of our invention, the guide is made of a frangible material, such as Bakelite or other brittle plastic, and preferably it is glued to the end of the shell or otherwise mechanically secured thereto. After the cable has been fully inserted, then the 'guide is gripped by a clamp or a nutcracker type of hot-stick device which crushes the guide and permits the parts to vdrop free of the power line.

It is undesirable to provide a guide of this type as a permanent part of the shell because the smaller diameter of the opening interferes with the desired stressV distribution at the outer ends of the jaws. Putting it another way, the cable should not be engaged by any portion of the wire gripping device other than the jaws themselves.

Since the shell is often fabricated by a swaging operation, it is not possible to impart the desired coniiguration to the open end of the shell so that it could function as an integral type of guide, even if this were permissible from the stress distribution viewpoint.

Therefore, it would appear that a nonintegral construction is indicated both from the viewpoint of stress distribution and also from the view point of manufacturing technique.

However, the difficulty encountered in having a strand guide which is fabricated separately from the wire gripping device, and securedl thereto by suitable interlocking or adhesive means, is that there is a danger of separation of the parts. In such event, the guide, being ring-shaped, would slide down the power line and come to rest at the bottom of the span, where it would collect dirt or foreign matter and serve as a locus of corrosion. Also, movement of the guide with respect to the line may set up radio and television interference in the vicinity.

Other objects, features and advantages will appear as the description proceeds.

With reference now to the accompanying drawings in which like reference numerals designate like parts:

FIG. 1 is a sectional view showing an installed deadend, with the removed strand guide shown in broken lines;

FIG. 2 is an enlarged sectional view of the strand guide alone;

FIG. 3 is a front view of FIG. 2;

FIG. 4 is a rear view of FIG. 2;

FIG. 5 is an enlarged sectional View of the front end of the shell;

FIG. 6 is a front view of FIG. 5;

FIG. 7 is an enlarged fragmentary view similar to FIG. 1, but showing the parts in a changed position; and

FIGS. 8 and 9 are views similar to FIG. 3, but showing modified'forms of strand guide;

FIG. 10 is a view similar to FIG. 2 showing a further modification; and

FIG. 11 is an elevation showing the present invention as applied to a line splice.

In FIG. 1 the wire gripping device 10 is a cartridge for a feed through deadend, the nature of the same being more fully described in Schweitzer Patent No. 3,098,275, granted July 23, 1963. The cartridge 1t) is interlocked with a clevis 11, the clevis forming a part of the deadend assembly and having means for connection to an insulator or other support, not shown.

The cartridge 10 as shown in FIG. 1 comprises a shell 12 having a tapered front portion 13 and an enlarged rear portion comprising the head 14. A tapered jaw assembly 15 is located withinv the shell 12 and comprises a plurality of jaws which are associated with eachother at one end by a connecting washer 17. There are preferably three jaws to the jaw assembly, and they are provided with suitable conductor gripping surfaces. When tension is applied to the cable 1S, the jaw assembly moves to the left, and the taper of each jaw cooperates with the taper 13 of the inner surface of the shell to urge the jaws into gripping engagement with the cable 18. The washer 17 provides means for maintaining the relative longitudinal positions of the j'aws without interfering with their radial movement.

The jaw assembly 1S is urged to the left and into conductor gripping position by means of a coil spring 19 which is coniined between the rear end of the jaw assembly 15 and a spring abutment 20 in the form of an inwardly directed flange formed integrally with the shell 12. The spring abutment 2t) defines the rear opening 21 of the shell through which the slack end of the conductor extends.

At the front end of the shell and located in the opening thereof, is a pilot cup 23. It will be observed that the pilot cup has flared marginal portions 24 which engage with the edge 25 of the opening. The arrangement is such that when the end portion 26 of a cable 18 is inserted into the pilot cup V23 and a moderate degree of pressure applied, the flared portions 24 will readily be deformed and permit inward movement of the pilot cup as shown in FIG. 7.

The strand guide 30 is a hollow cylindrical member made of a frangible material such as a phenol formaldehyde (Bakelite) thermosetting resin. As shown in FIGS. 2, 3 and 4 it has a ared Vopening 31 at the front end, and a counterbore 32 at the rear end which is adapted to iit over the tapered end of the shell 12. The counterbore 32 may be slightly flared, as at 33. The counterbore 32 thus forms a recess the bottom of which is in the form of a shoulder 34 against which the edge 25 abuts. Considerable space is thus provided between the wall of the counterbore 32 and the surface of the shell 12, and this space is filled with a suitable adhesive 35, such as casein glue. Thus the strand guide 30 is securely fastened .to the end of the tapered shell 12.

It will be observed that the minimum diameter or neck of the flared opening 31 is smaller than the diameter of the pilot cup 23. Thus any cable end which passes through the flared opening 31 will be easily accommodated within the pilot cut 23, and the act of insertion causes a cen- Ytering of the end portion 26 with respect to the cup 23.

The Ldiameter pf `the ppening 31 in turn is slightly larger than the nominal diameter of the cable 13 so as to pass any tangs which may be formed on the cable end 26 incident to the cutting thereof. Even where the over all cable diameter due to the presence of a tang is slightly larger than the opening 31, insertion is possible with a very small increase in the degree of force required due to the softness of the aluminum strands and due also to the smoothness and surface hardness of the material from which the strand guide material is fabricated. However, where the size of the tang is such that insertion is difficult, the cable is recut in the hope that a new cut will result in a smaller tang.

Once the end portion 26 passes through the opening 31 and is received within the pilot cup 23, the relative movement of the parts is continued until the cable is projected all the way through the deadend into the gripping position of the parts shown in FIG. l. At this time, the strand guide 3u is squeezed with a nut-cracker type of device, so that it will break into several parts and fall away, or struck with a heavy instrument. Thus there will be no possibility of contact between the installed cable 13 and the neck of the opening 31.

If desired, the recess provided by counterbore 32 may be undercut below the shoulder 34, as shown at 35 in l FIG. 2. The undercut recess thus cooperates with the frangibility of the material to a greater or lesser degree, depending upon the extent of undercutting, to facilitate the breaking of the strand guide into several pieces.

In the modification of FIG. 8, the strand guide 30 is made from a thermoplastic material, such as poly propylene. Since this material is not as brittle as Bakelite, removability from the line is effected by making the strand guide in two halves 37 and 38 which are releasably engaged with each other by rounded lugs 39 which extend into recesses 40. One or both of thehalves 37 is provided with a tab 41 having an opening 42 therein which can be engaged by a hot stick hook to yank the halves apart and break the adhesive bond 36, which in this case should be rather Weak.

In FIG. 9, a deep score providing a thin hinge portion 43 is substituted for the upper lug 39. In the case of polypropylene, the hinge is very flexible which permits the halves 37 and 38 to be injection molded in the open position; then closed and glued to the shell. A yank on the single tab 41 will open up the lower lug 39 and pull both halves away. A similar result can be achieved by shaping a split ring of a tough strippable sheet material, such as vulcanized fiber, to provide a flared opening 31 at one end and a counterbore coniiguration 32 at the other end as shown in FIG. 10, the split 44 permitting the same to be stripped away from the shell to which it is adhesively secured.

In all of these arrangements the neck of the ared opening 31 is smaller than the I D. of the pilot cut. Thus, the strand guide serves not only as a locating device and a go-no-go type gauge, but also as a strand compressor. Spreading of the outer aluminum strands is particularly prevalent in the case of ACSR due to the set taken by the steel core when wound on the storage reel.

Furthermore, the adhesive connection helps to maintain the pilot cup 23 in place against inadvertent ejection when engaged by the jaws; in some instances, indeed, the pilot cup, when thus firmly secured by the strand guide 30, serves as a stop which prevents wedging of the jaws in the taper 13, which occurs in certain types of taper.

The present invention is equally applicable to a line splice 3S as shown in FIG. 11, and also to other types of line splicing or deadending equipment when it is necessary to insert the line strand into the opening of a sleeve or shell.

Although only preferred embodiments of our invention have been shown and described herein it will be understood that various modifications and changes may be made in the constructions shown without departing from the spirit of our invention as pointed out in the appended claims.

We claim:

1. A wire gripping device comprising a tapered tubular shell having at one end an annular edge defining an end opening, a tapered jaw assembly slidably mounted within said shell, a pilot cup disposed in said end opening and having a ared deformable marginal portions engaging said annular edge, a strand guide disposed externally of and mounted on said shell at said one end and comprising a cylindrical member having a flared opening extending inwardly from one end, and having a counterbore extending inwardly from the other end, the counterbored end of said cylindrical member fitting over said one end of said shell, and the minimum diameter of said flared opening being less than the diameter of said pilot cup, said strand guide being a molded product -formed from a frangible synthetic resin material.

2. A wire gripping device as claimed in claim 1 in which said counterbore provides a recess, the bottom of which forms an annular shoulder which abuts said annular edge, the bottom of said recess being undercut beneath said shoulder to increase the frangibility of said strand guide.

3. A wire gripping device as claimed in claim 1 in which said strand guide is adhesively secured -to said shell.

References Cited by the Examiner UNITED STATES PATENTS 1,854,783 4/32 Cook 24-126 2,128,832 8/38 Lusher 24-126 2,166,457 7/ 39 Berndt 2li-81.25 3,059,208 10/ 62 Concelman 339-65 3,098,275 7/ 63 Schweitzer 24-126 DONLEY J. STOCKING, Primary Examiner.

Claims (1)

1. A WIRE GRIPPING DEVICE COMPRISING A TAPERED TUBULAR SHEEL HAVING AT ONE END AN ANNULAR EDGE DEFINING AN END OPENING, A TAPERED JAW ASSEMBLY SLIDABLY MOUNTED WITHIN SAID SHELL, A PILOT CUP DISPOSED IN SAID END OPENING AND HAVING A FLARED DEFORMABLE MARGINAL PORTIONS ENGAGING SAID ANNULAR EDGE, A STRAND GUIDE DISPOSED EXTERNALLY OF AND MOUNTED ON SAID SHELL AT SAID ONE END AND COMPRISING A CYLINDRICAL MEMBER HAVING A FLARED OPENING EXTENDING INWARDLY FROM ONE END, AND HAVING A COUNTERBORE EXTENDING INWARDLY FROM THE OTHER END, THE COUNTERBORED END OF SAID CYLINDRICAL MEMBER FITTING OVER SAID ONE END OF SAID SHELL, AND THE MINIMUM DIAMETER OF SAID FLARED OPENING BEING LESS THAN THE DIAMETER OF SAID PILOT CUP, SAID STRAND GUIDE BEING A MOLDED PRODUCT FORMED FROM A FRANGIBLE SYNTHETIC RESIN MATERIAL.

Images