Ground fitting

Feb. 1, 1955

2,701,351

W. H. WEBER

GROUND FITTING

Filed Sept. 28, 1951

<img file="US2701351A_D0001.tif" />

Attorney

2,701,351

Patented Feb. 1, 1955

United States Patent Office

2,701,351 GROUND FITTING

Walter H. Weber, Metuchen, N. J., assignor to The Thomas &amp; Betts Co., Elizabeth, N. J., a corporation of New Jersey

Application September 28, 1951, Serial No. 248,817

Claims. (Cl. 339—265)

The invention relates to a heavy duty ground fitting by means of which one or more grounding wires of the usual sizes are electrically connected to some grounded structure, such as a water pipe, in order to ground electrically a house or similar electrical system.

More specifically defined, the invention relates to an improvement in that type of ground fitting in which a large size water pipe is clamped within a U-bolt and its saddle which bridges the space between the shanks of the bolts and to which fitting, if desired, an electric conduit and cable anchoring means, generally known as conduit hubs, are clamped to connect an extremely small size wire to the water pipe, either with or without the large size grounding wire for which this particular fitting is designed.

In actual practice these ground fittings are required to meet varying situations in service, for instance, the size of the available water pipe may vary; the ground wire for connection to the water pipe is of varying size, sometimes being very small compared to the size of the pipe; the ground wire may sometimes be bare and at other times, paticularly in the case of small size wires, is provided with an insulating jacket; or the ground wire may be contained in a conduit, and quite often a particular job requires that the ground wires, both small and large, extend either parallel to or at right angles to the length of the pipe. Heretofore, each particular requirement has necessitated a form of or size of fitting fashioned more or less particularly for the job at hand.

The primary object of the invention is to provide a standard form of ground fitting which can be utilized in these several different circumstances and thus can be used selectively either to locate a very small ground wire with its conduit hub at any one of many angles to the length of the saddle, or in the case of the usual large size bare wires to provide for its continuous grounding along one pipe parallel thereto where the circumstances dictate such a relation, or for multiple bonding across two or more parallel pipes by utilizing two or more of these standard fittings with a jump-over wire therebetween.

It will be understood that ground fittings of the above type are subjected to powerful squeeze forces for effecting the necessary binding engagement with both the water pipe and the ground wires. While steel U-bolts of proper size are usually capable of taking the tension pulls imposed on their shanks without noticeable deformation, it has been necessary heretofore to make the saddles of quite thick plates in order to avoid buckling as they tend to wrap themselves about the adjacent side of the pipe to which they are clamped, especially when the pipe is of relatively small size. Making the saddles of a heavy massive plate adds to the cost, especially as it must be made of copper or an equally highly conductive grade of metal, and this is economically impractical.

Accordingly, another object of the invention is to procide a form of saddle capable of maintaining its factory predesigned configuration even when subjected to the powerful deforming forces usually employed in mounting such fittings in place, and to attain this fixity of contour under deforming forces, even though in the instant disclosure there is less material used in forming the saddle than has been used heretofore.

Broadly, the above objectives of the invention are attained by providing a form of saddle which features a peculiar distribution of metal in its design, and the providing at one end of the saddle of a construction fashioned to receive, if desired, a conduit hub, especially in the case where small size wires are to be used, and at its other end the saddle is fashioned to provide an element of a wire clamp for receiving wires which extend selectively either parallel to or at right angles to the length of the saddle, and the companion element of the clamp is a rotatably-mounted lever-forming jaw shiftable at will into a clamping engagement with the ground wire as it lies in either of such positions.

Still another object of the invention is to provide a form of saddle designed to resist bending and other distortional strains to which such saddles are subjected in service and at the same time, by proper distribution of metal, massing the same where necessary and thinning it out where strength is not a controlling factor, to thus economize in the amount of metal used.

It would be quite an advantage in mounting ground fitting as herein disclosed to the water pipe and ground wire to effect a final tightening action of the fitting by the manipulation of a single clamping arrangement and to do this without rupturing either the fitting or the wires clamped thereby. However, if that powerful squeezing force were used on the ground wire which is found necessary to effect a good electric contact over the more extensive area of the pipe gripped thereby, the ground wire would often be damaged.

Accordingly, the present disclosure features a ground fitting which includes a lever arrangement by means of which a manual force, even a powerfully multiplied manual force, applied to a nut-bolt squeeze combination provides a mechanical advantage in that the manual force operating through the unit is doubled in its squeeze effect on the pipe where it is needed, and provides a mechanical advantage in that the same manual force operating through the nut is halved in its squeeze effect on the ground wires where a powerful squeeze force is not desired.

The disclosure particularly features a ground wire clamp by means of which a ground wire which may be extending parallel to the length of the pipe clamp and thus at right angles to the length of the pipe, or which may be extending at right angles to the length of the pipe clamp and thus parallel to the length of the pipe, can equally be clamped in position simply by rotating the shiftable jaw element of the wire clamp into its intended relation to the ground wire and applying screw pressure.

Various other objects and advantages of the invention vzill 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 ground fitting embodying 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 accompanying drawings—

Fig. 1 is a view largely in side elevation of a ground fitting forming a preferred embodiment of the invention shown in position clamping a water pipe with a large ground wire extending parallel to the pipe on the right side thereof and showing a conduit hub carrying a small ground wire secured to the fitting at the opposite or left side of the pipe;

Fig. 2 is a plan view looking down on the showing in Fig. 1 with the conduit hub omitted;

Figs. 3-5 are each detail showings of the wire clamp at the right side of the saddle in Figs. 1 and 2, Figs. 3 and 4 being showings in plan, respectively, of the top side and the under side of the wire-receiving socket, and Fig. 5 being a plan view of the under side of the lever forming the wire clamping jaw shown in side elevation in Fig. 1 and in plan in Fig. 2;

Fig. 6 is a diagrammatic representation of the leverages provided by the saddle and jaw acting on the pipe and ground wire of the preceding figures; and

Fig. 7 is a plan view of the adjacent sides of two pipes in parallel relation and interconnected electrically by a jumper wire secured to the pipes by a pair of the ground fittings such as are shown in Figs. 1-5.

In the drawings and referring first to Figs. 1 and 2, there is disclosed a six inch steel or iron water pipe P and a fitting 10 forming a pipe clamp encircling the same and forming a wire clamp for engaging a large ground wire C. The pipe clamp comprises two jaw elements, one

2,701,361 constituting a U-bolt 11 in the crotch 12 of which more or less fits the under side of the pipe P. The bolt includes a pair of upstanding, parallel threaded shanks 13 passing loosely through the two end portions of the saddle and secured conventionally by nuts. The U-bolt and its associated nuts are formed of steel and hot-dip galvanized.

A bronze casting 14 forms a saddle which bridges across the space between the shanks of the U-bolt and mid-length thereof is provided with an arched portion 15 which overlaps the side of the pipe opposite the side engaged by the crotch 12. Opposite ends of the saddle form outstanding, rugged, flat ears 16 and 17 each provided with a shank passage or bolt hole 18 extending thereto and through each of which a shank 13 of the bolt extends. One of the ears 16 will be referred to sometimes as a hub nest and the other ear 17 as a wire nest.

The arched portion 15 forms a curved plate with marginal reinforcements as hereinafter described and is provided on its underside, that is, the side engaging the pipe, and on opposite sides of the medial plane v—r thereof bisecting the arched portion 15, with two sets of V-teeth, a left set 19 and a right set 20, separated at the crown of the arch by a wide, shallow blank space 21 which extends transversely from edge to edge of the saddle. Each set of teeth comprises five teeth arranged in parallel relation and grouped into an outer group 22 of three teeth and an inner group 23 of two teeth, with the groups separated by a shallow groove 24. For convenience of reference hereinafter the ten teeth are marked clockwise in Fig. 1, with refernce characters a—j.

The three teeth forming the outer group 22 in each set are positioned with the same length radius measured from center c in the axis v—r and with relatively long radii, such as a—c, c—j; and the two teeth forming the inner group 23 in each set are positioned with the same length radius, measured from a center c' in the axis v—r and with relatively short radii, such as c'·—d and c'—g.

This peculiar arrangement of teeth in sets grouped on opposite sides of the crown of the arch-shaped clamping jaw provides a better and more positive form of gripping surface for engaging the cylindrical peripheries of pipes of different diameters than would be the case where the teeth were continuous and equidistantly spaced in an arc across the crown without grooves therebetween, or where the arched gripping surfaces were entirely free of teeth and more or less smooth.

In the particular case illustrated, that is, with a large size pipe P, it is only the outside groups of three teeth each which are in bearing contact with the perimeter of the pipe P. The two teeth groups 23 are not in contact with the pipe illustrated, but would be in bearing contact with the perimeter of a slightly smaller pipe, and in which case the outer sets 22 would be spaced outwardly of any such relatively small diametered pipe.

The advantage of this spacing of groups of teeth shown in a little different form than herein illustrated is more fully set forth in the pending application of George C. Thomas, Jr. and Walter Weber, Serial No. 230,358, filed June 7, 1951 now Patent 2,679,032.

The portion of the saddle in the central arch portion thereof between its hub and wire nests is reinforced along its long edges by upstanding flanges 25 and 26, which makes this portion of the saddle channel-shaped in cross section, thus providing the reinforcing feature of channel forms. The ear 17 forming the wire nest is particularly reinforced and for this purpose its under side is provided with a depending reinforcing rib 27, horseshoe shaped in plan as shown in Fig. 4 and encircling the bolt shank passage through the ear so reinforced by the horse-shoe rib. The right ear 17 is thick and forms the relatively fixed jaw element of the wire clamp; is somewhat rectangular in form and wider than the arched portion 15 as shown in Fig. 3; and its upper side is provided along each of its outlining edges with a shallow indentation. Two of these indentations are open at opposite ends, extend at right angles to each other, and form wire-receiving seats or recesses for receiving conductors like the conductor C. One of these indentations or recesses 28 is located close to the free end of the ear 17 and extends transversely of the length of the saddle for its entire width. The recess 29 extends parallel to the length of the saddle and is outwardly offset from the ad4 jacent upper side of the arch portion 15 as shown in Fig. 3. Located between each of these recesses 28 and 29 and the centrally located shank passage are short upstanding ribs 30 and 31, extending in planes at right 5 angles to each other and each rib terminating short of the plane containing the other rib. The other two indentations, of which one marked 32 parallels the recess 28, and the other marked 33 parallels the recess 29, and in each case forms a fulcrum-forming groove. 10 It is within the scope of this disclosure to omit any distinct grooves and to form the surfaces more or less flat in the regions marked 32 and 33, as the lever hereinafter described does not necessarily have to be seated in a groove in order to rock.

A lug 34 projects beyond the free end of the wire nest 17 mid-length of the width thereof and coacts with the rib 30 (see Fig. 3) to form a wide-spreading, U-shaped groove mid-length of the recess 28. Similarly, a lug 35 projects laterally from the side of the wire nest 17 oppo20 site the short rib 31 and likewise forms a wide-spreading, U-shaped groove mid-length of the recess 29.

The movable jaw element 36 of the wire clamp is somewhat arched in side elevation as shown in Fig. 1 and is formed as a hard copper casting. The jaw 36 is 25 provided centrally thereof with an elongated slot 37 through which the associated right shank 13 is passed; and whose outer face in the part thereof about the slot provides a seat for engagement by nut 38 threaded on the right shank 13. One down-turned end of the jaw 30 is reduced in width and forms a fulcruming flange 39 fashioned for rockably engaging selectively in either of the fulcrum grooves 32 or 33, or on the top face of the wire nest 17 in the absence of the fulcrum grooves. As the pressure is applied between the fulcrum and the 35 work end, this makes the jaws a lever of the second class.

The edge of the lever opposite the flange 39 is bifurcated to form a pair of hook-like lugs 40 with the space 41 therebetween dimensioned to receive either of the lugs 34 or 35 depending upon the rotative po⁴⁰ sition of the lever jaw. The locating of either of the lugs 34 or 35 in the space 41 forms in each case an interlock which tends to defeat separation of the jaw 36 and the wire nest 17 in a direction rotatively about the associated shank 13. The extent to which the lugs extend ⁴⁵ into the space 41 is dependent upon the diameter of the wire C for the time being engaged by the wire clamp.

Between the lugs 40 and the bolt slot 37 there is formed a wall 42 which in its engagement with the outer side of either of the short ribs 30 or 31 tends to resist shift5θ ing out of whichever of the fulcruming grooves 32 or 33 the flange 39 happens to be engaging at the time. For the purpose of receiving whichever of the ribs 30 or 31 is not so functioning, the under side of the lever 36 is provided on opposite sides of the slot 37 with a pair 55 of sockets 43 and 44. The under side of the jaw in the portion thereof which forms the pair of lugs 40 and the wall 42 is concaved and forms an upper, downwardly-facing, wire-engaging channel 45 interrupted on _Λ one side and mid-length thereof by the space 41 as shown ⁶⁰ in Fig. 5.

The hub nest formed by the left ear 16 is provided on its upper side and concentric with the associated shank passage 18 with a circle of upwardly-facing V-teeth 46 and is otherwise fashioned to receive a wire-carrying at65 tachment, such as an auxiliary conduit or an armoured cable member arranged to extend therefrom in any one of a number of angled relations to the length of the saddle.

In the instant form of the invention illustrated there • ® is disclosed such an attachment constituting a conduit hub 46 which may be any of the usual forms of such hubs, such, for instance, as the conduit-angling device shown in the patents to Stephen N. Buchanan, No. 1,887,193, November 8, 1932; No. 1,897,186, February 14, 1933; 5 and No. 1,899,309, February 28, 1933.

In any case, the hub 47 includes a base plate 48 provided on its under side with a circle of teeth 49 fitting the teeth 46 any one of a large number of positions in which the hub may be rotatively adjusted about the left 80 shank 13 as a pivot. The hub contains a small ground wire 50 connected electrically to -the base plate and therethrough to the saddle, following conventional practices in this respect. A nut 51 threaded on the associated shank 13 bears through a washer 52 to clamp the hub 85 to the saddle. Of course, where the hub is omitted the

2,701, nut 50 may be lowered to a bearing engagement with a flat portion of the saddle surrounded by the teeth 46, as suggested in Fig. 2.

In operation and assuming that the U-bolt and saddle have been looped more or less loosely about the pipe P 5 and with the shiftable lever-forming jaw 36 in the position illustrated in Figs. 1 and 2, that is, with the jaw extending lengthwise in the saddle with its bifurcated end straddling the lug 34 and its flange 39 rockably bearing in the groove 32, a cable C may be inserted between the 10 wire-receiving recess 28 of the wire nest and the channel 45 of the shiftable jaw. The nuts threaded on the shanks 13 are then tightened, alternately one and then the other, until firm contact is made with both the pipe P and wire C. Finally, a powerful squeeze pressure is developed by 15 turning nut 38 until it will turn no further. This has the effect of securing the pipe rigidly under load between the crotch of the U-bolt and the arched central portion of the saddle with the teeth of the saddle biting into the perimeter of the pipe at two spaced-apart points or, rather, 20 groups of points, as above indicated. At the same timetightening the right nut 38 will cause the lever-forming jaw to engage the cable C to clamp the same firmly and immovably in place, squeezed between the recess 28 and channel 45 as indicated in Fig. 1. In this way the pipe 25 clamp is firmly attached to the pipe and the ground wire C is firmly attached by means of the lever-acting jaw of the wire clamp to the saddle element of the pipe clamp.

Assuming, instead, that a cable, such as jw in Fig. 7, is located in the recess 29 rather than in the recess 28, 30 the jaw is rotated ninety degrees from the position shown in Figs. 1 and 2 about the associated shank as a pivot until its fulcruming flange 39 is rockably located in the groove 33 and its lug 35 is in the space 41, the associated nut 38 is advanced as before, and the cable in this case is se- 35 cured in position as before described, except that it is now located parallel to the length of the saddle or at right angles to its position in Figs. 1-3.

The latter situation is employed in the showing of Fig.

7. In this case there are shown two pipes P' and P², 40 each separately encircled by a pipe clamp such as previously described with the corresponding reference characters primed, in the case of the fitting engaging the pipe P². Opposite ends of a jumper wire jw are clamped between the wire nests 17 and the rotatably adjustable 45 jaw element 36 of the wire clamps of the two fittings.

Considering the final pressure exerted on the assembly in either case by reason of the final turn of nut 38, it will be seen that the pressure is resolved into a very large component acting to squeeze the pipe and a relatively SO small component acting to squeeze the ground wire C or jw.

As by reference to the diagram of Fig. 6 it is seen that in so far as the pipe is concerned the nut pressure originating in the right nut 38 acts with a long work leverage k—I, 55 and a short power leverage k—m, so that there is attained a mechanical advantage with the dimensions illustrated of one to two. This means that at the final turn of the nut 38 there is attained a powerful squeeze action on the pipe centered along the plane v·—&gt;·. In so far as the wire C θθ is concerned, the short work-leverage η—o provided by the second class lever 36 operates in effect on the wire over the long power leverage n—p so that there is a mechanical disadvantage of two to one. This means that only a small percentage of the nut thrust is applied to the 6a ground wire C.