US2555099A - Hot line clamp - Google Patents

Description

May 29, 1951 L.. A. THOMAS HOT LINE CLAMP Filed Dec. 8, 1945 mVENToR. ac/AN A?. THU/WAS Patented May 29, 1951 HOT LINE CLAMP Lucian A. Thomas, St. Louis, Mo., assgnor to The Thomas & Betts Co., Elizabeth, N. J., a corporation of New Jersey Application December 8, 1945, Serial No. 633,748

3 Claims. 1

This invention relates to a hot line tap for connecting a tap or lead line to an overhead powerline sometimes hereinafter referred to as the main line without interrupting the current flow through the main power line.

Such light duty devices now known on the market are formed of a length of wire coiled back and forth into a downwardly opening spring clamp which is lifted into position overlapping the line by means of a clamp stick and then lowered by the stick 'into a resilient clamping with its relatively frail wires in engagement with the main line.

These devices have many objectional features and have not proven satisfactory in actual service. For instance their engagement with the main line is somewhat casual with the result that they tend to hop off the main line due to its vibration caused by high winds. Further, these old devices depend for their mechanical engagement with the line upon their inherent spring characteristics but the springs lose their clamping capacity when for long periods of time the heat of the connection causes the metal to anneal and the spring to weaken its gripping effect. As presently designed, these known forms of hot line taps have the lead wires connected thereto in such a way as to interfere with the movement of the clamp stick in inserting and removing the tap from its position engaging the line and are in the Way of the operators as they manipulate the stick.

The primary object of the invention is to provide a simple form of hot line tap which, negatively will avoid these objectional features and which, positively will remove the tap out of the way of theoperator, which will provide a form of tap which can be formed largely as a simple bending and stamping operation and thus easy to manufacture; which will be easy to install in position hooked over the line even in the presence of ice and stormy weather conditions; which will provide for an extensive area of contacting surface between the tap and line, and which will be positively secured to the line and maintained in a tight connection therewith even if the line does vibrate violently back and forth due to storm and wind conditions.

Broadly, the invention features a hot line tap formed of a broad strip of conductive and springy metal, bent back upon itself somewhat U-shaped; normally tending to spring its arms apart to permit its being hung on the line, and provided with a bolt capable of being operated from a position beneath the same by a long reach tool or clamp stick, the socket of which engages the eye of the clamp to place it into position secured to the wire. The invention also features an organization of lifting eye, turn bolt eye and lead wire arranged so that the lead wire will not interfere with the clamp stick as it is raised to transport the tap or to turn the bolt;

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the drawings:

Fig. 1is a View in side elevation of a hot line tap constituting a preferred embodiment of the invention and shown installed in position hanging from a power or main line and suspending a lead line therefrom;

Fig. 2 is a view in front elevation of the device looking at the same from the right side of Fig. 1, and;

Fig. 3 is a sectional view taken axially of the holt, on the line 3-3 of Fig. l looking in the direction of the arrows and showing in dotted outline the upper slotted end of a clamp stick engaging the bolt eye in position to rotate the bolt.

In the drawing there is shown an overhead electric conductor main or power line A intended to be engaged by the hot line tap herein featured and which line A in this art is commonly referred to as a hot line because it is carrying electric current, sometimes at high voltage. It will be assumed that it is desired to tap current off this line to supply some electrical equipment, such as a small transformer or to make an independent connection to a lightening arrester. Current is led to such apparatus through a tap or lead wire or line B which is disposed in position hanging from the main line A and electrically connected thereto by the hot line tap or connector Ill herein featured. The tap comprises primarily a wide and relatively thin strip of metal, such as copper, bent back upon itself in substantial U-shape to form at its crotch an upper or lift eye l! and immediately adjacent thereto an upper broad fiat side l2 and a similar lower flat side i3.

Normally the sides l2 and i3 tend by reason of the resiliency of the metal of which the tap is formed, to spring outwardly from the locked parallel position shown in Fig. 1 and thus assume a wide angle materially greater than that shown and which will tend to facilitate the hooking of the tap over the line A. The arms are drawn together against the load tending to hold them in open position by means of a clamping device designated generally by the reference character III. This clamping device includes an eye bolt I5 which is passed loosely through the lower arm I3 as best shown in Fig. 3, and has its upper end threaded as shown at I6. The shank of the bolt is provided with a stop shoulder I1 which normally bears on the outer lower exposed face of the side I3 and thus limits the movement of the lower side I3 downwardly away from the upper side I2.

The bolt at its lower end is formed into a depending eye I8 hereinafter referred to as the lower or bolt eye to distinguish it from the upper eye |I. The threaded end I6 of the bolt works into the lower open end of a long nut I9 secured to the upper side I2. In the form illustrated the nut is provided with an outstanding flange 2l) which is secured to the upper side I2 by means of screws 2l. The threaded portion of the bolt is of sufficient length to permit a rather extensive opening of the sides II and I2 when permitted to retreat into their fully open position under tension of the length of spring material of which the tap is formed. The portion of the bolt between the sides I2 and I3 as viewed in Fig. l acts as a stop to limit the relatively upward advance of the line A when the tap is hooked over the same and lowered into place.

The sides I2 and I3 are provided respectively with opposing outturned ares 22 and 23 located immediately in advance of the bolt. At the center of each flare the opposing fiat sides I2 and I3 are slightly notched or recessed or rather bent outwardly as shown at 2li and 25 to provide opposing rounded channels or seats facing eachl other for receiving the line A therebetween. The flares each provide a reinforcement of its associated side at the portion designed to engage the line and at the point where breakageis most likely to occur. The sides do not have the resiliency characterizing the balance of the tap struc ture as these flares tend to resist buckling of the otherwise flat plate-like sides. It is a feature of this disclosure that the clamping jaws are formed of one piece of spring metal preferably of wide stock and capable in all parts thereof of possessing a high degree of elasticity in directions normal to their flatwise dimension. By reason of this flexibility the outer end of the wire-engaging seats of the clamp, that is, in the region of the ares 22, can bend somewhat with the vertical vibrations of the conductor and thus the pressure on the conductor is gradually lessened considerably from the center of the clamp toward each of said ends. In this way there is minimized any tendency to concentrate stresses in the conductor at the end of the clamp due to bending of the conductor. The give of the jaws in bending helps to reduce vibration of the conductor and thus of the stresses to which the conductor is subjected. In this way possibilty of vibration fatigue failures of the conductor is minimized.

At the point where rigidity in distinction from flexibility is desired, that is, between the load imposing line of thrust provided by the bolt and the load-resisting line of yresistance to thrust provided by the squeezed line A, the otherwise highly desirable springy parts of the clamp are reinforced and thus made a little more stiff and rugged than the balance of the clamp. The lower side I 3 is stii'fened materially for a small area by the stop shoulder I1 bearing thereon, thus forming two thicknesses of material at this point in the bolt thrust line, and immediately adjacent thereto the lower arm is bent transversely and the plate so bent is anged at its two ends and thus strengthened somewhat against bending in two directions by the out-turned flares 23. The upper side I2 is similarly stiffened materially across its width by the double thickness of material provided by the flange 20 in the region of the bolt thrust line and immediately adjacent thereto and forming in effect a continuation thereof the upper arm is bent transversely and the bent portion flanged at its ends and thus strengthened at least somewhat against bending in two directions by the out-tured flares 22. It is suggested that where a greater degree of spring is desired at this portion of the tap, the flares may be omitted but in this case the groove-like seats 24 and 25 are preferably retained.

The upper side I2 is continued downwardly in its own plane to provide a relatively long upper hook plate 25 designed to reach for and overlap the line as the tap is caused to approach the line as it is installed in position. Just below are 23 and the lower seat 25, the lower side I3 is bent down sharply to form a substantially vertically extending lower hook plate 2I. The two depending hook plates 26 and 21 coact to form a downwardly facing saddle of inverted V-form with a wide open throat designed to receive the main line A, and when the upper plate rests on the line the lowering of the tap either by pull or by reason of its own weight will cause the underside of plate 26 to slide down on the line, thus automatically guiding the main line A towards its seat at 2li- 25.

The upper end of the lead wire B is preferably bent at an angle, and the angled end extends through an opening provided therefore in the plate 21. The lead line is secured to hang freely from the plate by being passed through the headed end of a bolt 29 in turn passed through an opening provided therefore adjacent the lower end of the plate 21. The wire B is secured flatwise against the inner side of the depending plate 21 and is secured by means of a nut 30 threaded on the bolt 29.

In operation the tap is assembled by the operator by locating the lead wire B in position bolted to the tap as thus described. By manually reversing the bolt I 5, the sides of the tap are permitted to open wide under their inherent spring tension to form a wide open downwardly facing saddle. By the use of a clamp stick C, or equivalent long reach member, the operator eX- tends the socket over the eye of the clamp and elevates the tap with the lead wire trailing therefrom into position hooking the upper plate 26 on the overhead power line A. It is also suggested that by means of a disconnect stick he may engage the lift eye Il to position the tap on the main line A. In either case the undersurface of the upper hook plate 26 slides down across the line A and thus in effect guides the tap into place until the line A is disposed adjacent the bridging portion of the bolt which is exposed between the sides l2 and i 3 and thus at or adjacent the channel recesses 24 and 25. The operator rotates the clamp stick as it engages the eye I 8 about its own axis turning the bolt in a direction to cause the sides I2 and I3 to approach each other against their own spring tension. As the jaw forming portions outlined by the flares 22 and 23 ofthe Sides I2 and I3 approach each other, the line A in effect nds its way into the notches 2d and 25 if not already there. By continuing the rotation of the bolt the jaws are advanced towards each other and nally the line A is positively and securely locked within the clamp and thus connected to the lead wire B hanging therefrom in more or less vertical alignment therebelow. In this way the line B is secured in place and positively connected both electrically and mechanically to the lineA with no dependency upon the spring jaws to effect the clamping security.

Should it be desired to disconnect the tap from the line, the operator proceeds in reverse steps, that is the operator reinserts the clamp stick over the bolt eye I 8, and by re-rotating the same loosens the bolt thus permitting the jaws of the clamp to spring apart automatically with the tap loosely hanging from the line. Then by removing the clamp stick from the eye I8 and engaging it in the upper eye l I, the tap may be lifted bodily ci the line and lowered to the ground.

By means of a device of the character thus described it is possible to provide an extent of metal-to-metal engagement with the line A on both its upper and lower portions for an area equal in length to the entire width of the strip of which the tap is formed. The clamp when once set by the turning of the eye bolt is maintained in its clamped position until the bolt is intentionally released. These taps have been known to remain fixed in position in the presence of storms and other conditions which, with known forms of similar taps have become loosened after having been in use for a while. On the other hand with known forms of taps their threads on the bolt tend to corrode causing their clamps to freeze on the line so that their removal is difficult. It is also appreciated that the bolt construction as herein disclosed is rugged and has a crushing capacity suitable for breaking through any ice which might have accumulated on the line A. Also the jaws have sufficient crushing strength to break through any oxidation which may form on the line -A when in nal clamping position to provide the desired all inetal-to-metal contact between line A and tap is.

I claim: p

1. A hot line clamp formed of a strip of flat spring metal bent back upon itself to form a bifurcated structure provided with a crotch forming a lift eye, the upper leg of the structure being straight with the portion thereof adjacent the crotch forming the upper element of a clamp, and therebeyond elongated to form a hook plate whose undersurface forms a guide surface for leading the line 'towards its clamped position, and the lower leg having the portion thereof adjacent the crotch forming the lower element of the clamp and therebeyond having its free end portion bent sharp-ly downwardly away from the upper leg to form a vertically depending hook plate, the upper leg provided with an opening extending therethrough and a long nut secured thereto at the place so weakened by the presence of the opening and thus reinforcing the upper leg, an eye bolt extending loosely through both the lower and upper leg and threaded into the nut, the lower end of the bolt provided with an eye accessible from a position beneath the device and said bolt provided with a broad faced stop shoulder at all times bearing on the underside of the lower leg to elevate the same towards the upper leg when the bolt is rotated by turning its eye and a lead wire replaceably secured to the downturned end portion of the lower leg and depending freely in longitudinal prolongation thereof the eye of the eye bolt and lift eye being in horizontally spaced apart relation and both horizontally offset from the depending hook plate.

2. A hot line connector comprising a flat strip of resilient metal bent back upon itself to form a pair of substantially parallel sides connected at one end to form an offset lift eye by means of which the connector may be hooked over and pulled down upon a main line, opposing faces of the parallel sides adjacent their outer ends provided with recesses forming rounded seats for receiving the main line therebetween, the lower parallel side provided with an extension bent down sharply just beyond its associated recess to assume a vertical position when the connector is in place and provided with means for demountably securing thereto a tap lead wire in position depending vertically below the extension the upper parallel side provided with an extension, said extension coacting to form a downwardly facing saddle of inverted V form, clamping means including a threaded nut secured to the upper side between the recess and eye and a bolt passed through both sides, in bearing engagement with the lower side and threaded into the nut secured to the upper side and arranged to move the sides into clamping engagement with the main line, the lower end of the bolt terminating in an eye adapted to be rotated by a reach rod engaging the same to turn the bolt, said bolt eye being horizontally odset from the saddle and from the depending extension and its associated tap line and accessible for rotation from a position beneath the connector thereby to permit the reach rod to find the bolt eye without becoming entangled with the tap lead wire depending from the connector.

3. A hot line connector comprising a broad nat and relatively thin strip of conductive spring metal bent back upon itself to form at its crotch a lift eye having a large substantially circular opening and immediately adjacent thereto two at parallel sides forming an upper side and a lower side at all times biased to spring outwardly relative to each other, the upper side being continued in its own plane to provide a relatively long upper hook plate designed to overlap the main line and in effect to guide the main line into the space between the parallel sides as the connector is lowered into place thereon, the lower side being continued and bent down sharply to form a depending lower hook plate, the portions of the parallel sides adjacent the eye provided with aligned bolt holes and the parallel plates between the bolt holes and the hook plates each having their opposite edges bent outwardly to form out-turned ares, each fiat side at the portion having the flares being bent outwardly and transversely to form a shallow recess and said recesses facing each other and coacting to form a wire clamping seat, said flares and associated recess forming bends coacting to provide at least some degree of reinforcement to the thin strip at the portion thereof forming the clamping seat while retaining capacity at the flared ends to respond to vibration in the main line, a long nut provided with a threaded bore in alignment with the bolt hole in the upper side and provided at one end with outstanding flanges secured in overlapped relation to the upper side and acting to give rigidity to the portion of the upper side so 7 overlapped, an eye bolt provided at its lower end with an eye and having its upper end passed through the hole in the lower side threaded into the nut and provided with a wide stop shoulder engaging the lower side and acting when the bolt is tightened to bear on the lower side to cause the sides to squeeze the main line on its seat, and means for securing a tap line to the lower hook plate, said connector with the tap line hanging therefrom being balanced relative to the main line clamped thereby to cause the lower hook plate to hang vertically and to locate the eyes both in horizontally oiset relation to each other and to the falling tap line whereby a clamp stick may have free access toreither eye without becoming entangled with the tap line.

LUCIAN A. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Baumel Apr. 1, 1919 Johnson July 8, 1924 MacFadden Nov. 4, 1930 Legg May 23, 1933 Hendee Oct. 3, 1933 Rudd Feb. 16, 1937 Crump Oct. 26, 1937 Smith Apr. 26, 1938

Images