US1899309A - Grounding fitting - Google Patents

Description

1933-1 s. N. BUCHANAN GROUNDING FITTING Filed July 26, 1929 anomwoz STEPHEN MBw/M/W luv mung

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Patented Feb. 28, 1933 UNITED STATES PATENT] o mcE. A

STEPHEN N. BUCHANAN, OF ELIZABETH, NEW JERSEY, .ASSIGNOR TO THE THOMAS & BETTS 00., OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY GROUNDING FITTING.

Application filed July 26, 1929; Serial No. 881,118.

on a water pipe or other ground conductor and shows an armored cable connected to the fitting to enclose a ground wire, the cableitself being insulated from the fitting, but the ground wire in the cable is electrically connected to the fitting.

Figure 2 shows a side view of Figure 1 as taken on the line 2-2 and shows a side view of the swivelled and insulated cable connecter. Fi re 3 shows a face view of the groundmg. tting from the opposite side of Figure 1 and illustrates the ground conductor such as a water pipe in dotted lines. This view shows the device provided with a plurality of pipe groove seats graduated in size for making an electrical ground connection with water pipes of .difierent diameter.

This invention relates to electrical connecting devices and more particularlyto grounding fittings for establishing a ground wire or electrical connection inhouse and building wiring systems to render the same safe by grounding oil and transmitting away stray current or short circuits to the ground through a water or gas pipe or other available conductor leading to the ground.

An object of the invention is to produce an improved grounding, fitting including means to establish a positive electrical connection with awater pipe or other similarly grounded conductor, as well as provide insulated anchorage means by which to attach to the fitting a ground wire protective covering such as an ordinary flexible metal armored cable,

and also to provide a suitable ground wire terminal connecter on the fitting, whereby the ground wire but not the armored cable may be electrically connected or grounded to said fitting and hence to the plpe.

A particular object of the invention is to produce a grounding fitting wherein the usual armored cable may be insulated from the ground fitting and in this way the ground wire installation itself is rendered safe for the reason that [current is not permitted to flow through the spiral armored cable since the latter, being a poor conductor of current, would heatand increase the fire hazard should current fiowtherethrough due to a break down or short circuit somewhere in the ground wiring installation.

A further object is to produce a grounding fitting having a cable connecter associated therewith, which connecter is insulated as aforementioned from the fitting and hence from the water pipe or other grounded conductor, and a pivotal connection may be used if desired to attach the insulated cable connecter to the grounding fitting.

\Vith the foregoing objects and others-in view. the inventionhas-relation to certain combinations and arrangements of the parts, examples of which are disclosed in the accompanying drawing, wherein:

Figure 1 shows a plan rear face view of the 53 grounding fitting attached to and grounded 4-4 of Figure 1 to illustrate one example of a combination insulator and swivel attachment on the grounding fitting to mount a cable connecter thereon.

Figure 5 is a section on the line 55 of Figure 4 showin parts of the combination insulated swivel y which a cable connecter is carried on the ground clamp fitting.

Figure 6 is a side elevation of a modified form of insulated and swivelled or pivoted bracket to which an ordinary or standard form of cable'connecter used in outlet boxes may be attached.

In the installation of wiring systems in houses, buildings and the like for general lighting or power work, there is usually available a ground conductor such as a water or gas pipe P to which the electrical ground wire system may be electrically connected or grounded to render the same safe by transmitting to the ground short circuits or other stray curren In this connection the contractor installing the ground wire W frequently employs a flexible metal armored cable BX, itself a poor electrical conductor, in which is carried the ground wire, one end of which is adapted to be electrically connected'with the pipe 1? and the other end to an outlet box or other part of the main wiring system not shown. Primarily, the urpose of this invention is to provide groun ing fittings or connectors by which that end of the 1 Figure 4 is an enlarged section on the line t ground wire W shown in the drawing and carried in the cable BX may be electrically connected or grounded to any available size pipe P so that the wire 1V and pipe P may carry away to the ground any stray potential existing in the main wiring installation not shown. Furthermore a feature which char acterizes this invention is the insulation means carried on the grounding fitting by which the cable BX, of poor conductivity, is insulated from the grounding fitting and from the pipe P so that the cable protecting the ground wire may not carry current and become hot due to a break down or failure somewhere either in the main wiring or circuit system or the ground wire.

Referring now to the drawing for a more detailed description of the invention, there is shown a pipe clamp which embodies the features constituting this invention. This pipe clamp comprises a yoke having threaded legs 8 carried on a yoke arch 9 which reaches over and clamps to the grounded water pipe P. A pipe seat 10 performs the function of a clamp strap to reach across the pipe in opposition to the arch 9 and this seat 10 may be made in any suitable form such as that shown in the drawing where a disc or circular pipe seat 10 is shown. However, the pipe seat or clamp strap 10 may be made square, rectangular or otherwise shaped depending on convenience of manufacture and requirements to be filled. A nut 11 acts as clamp operating means and threads on each leg 8 to grip the clamp 9-10 against a water pipe or other ground conductor.

\Vhile the pipe seat 10 may be made in various forms, one preferred embodiment thereof shown in the drawing and is suflicient to illustrate the principles of the invention. This pipe seat 10 is provided with a number of yoke receiving holes in pairs 13, and 21 made in the periphery thereof and these holes are appropriately arranged in respect to grooved and toothed pipe seats formed in that face of the pipe seat or strap 10 which is adjacent the yoke arch 9. Pipe receiving grooves 15, 16 and 17 of different standard pipe sizes are made in the pipe seat 10 and the embodiment shown is merely one example of this structure. As a matter of fact, three pipe seat grooves 15. 16 and 17 are shown and are related to the three pairs of holes 13, 20 and 21 but any. suitable number of grooves and holes may be provided.

he pipe receiving grooves 15, 16 and 17 are arranged angularly in respect to each other and the longitudinal axis of each groove passes through the center of the circular disc 10. This construction affords a maximum length for each groove and hence maximum contact making capacity with the pipe in the groove to be selected according to the size of pipe available. By centering each pipe seat groove at the center of the seat 10 itself, it is seen that each groove 15, 16 and 17 occupies the greatest dimension of the member and hence the advantage of arranging the longitudinal axis of the plurality of grooves coincident with the axis of the pipe seat 10. 4

As heretofore mentioned, two holes 13 that is a pair 13 are made in the periphery of the pipe seat 10 and these holes are isposed rightangular in respect to, say the smaller pipe seat contact groove 15. There are also shown and oppositely arranged the pair of holes 20 cooperating with the pipe seat groove 16. In the same way there is shown the third pair of holes 21 arranged transversely t0 the larger pipe seat 17. The several holes spaced about the pipe seat 10 are therefore arranged in pairs and in a plane passing through the axis of the seat 10 and transverse to the longitudinal axis of the several pipe grooves with which the clamp 9-10 engages the pipe P.

An important feature of the invention relates to a characteristic anchorage means used to attach the cable BX to the pipe clamp 910. This anchorage means performs two purposes, that of insulating the cable BX from the grounding fittings 9-10 and that of affording an adjustable swivel attachment, whereby the cable BX, in which the ground wire WV is enclosed, may be insulated from and attached to the grounding fitting, regardless of the direction in which said cable BX extends. cable BX may approach the grounded pipe or conductor in a direction parallel to the pipe P or in some angular relation thereto, but such a condition matters not for the reason that the anchorage device swivels on the grounding fitting 910 to make convenient the sim le operation of attaching the cable to the tting.

A swivel arm or bracket 24 carries an insulated anchorage on one end to attach it to the ground fitting and a cable connecter on the other end. Describing first the cable connecter end and one form of cable connecter by which the cable BX is attached to the bracket or arm 24, it is seen that the connecter may be constructed in any suitable form, and the example shown merely explains the principle of the invention. The bracket 24 in this instance carries a sleeve 25 made on its outer end and the sleeve receives the end of a cable BX thereinto. A screw 26 or other clamp means fastens the cable in the sleeve 25 and hence attaches the cable to the grounding fitting by a swivel insulator later described. The cable connecter simply comprises the screw 26 which loosely fits through a clamp yoke 27 and the screw 26 threads into a rib 28 formed on the sleeve 25. The yoke has its parallel legs 27 slidable up and down through an opening formed through the sleeve wall 25 on each side of the In other words, the

includes'a central perforation 32 :by'which to rib 28. In this way, the screw causes the inner ends of thezyoke 27 to grip thecable and anchor thelatter inIthe connectersleeve 25. The ground wire LV islead through the cable BX and through its connecter or anchorage: means 25 and has its free end stripped ofits insulation at 38 and coiled fit. the eye 30 over one of the clamp legs 8.

The nut 11 is then-tightened up toanchor the eye bracket'2430 to the grounding fitting. It is readily seen that the cable connecter may now be adjustably swiveled about the clamp leg 8 in order to line up the cable connecter sleeve 25 with the cable BX- In some forms of 'constructiomit is very desirable or even necessary to insulate the cable BX and its connecter25 from the grounding fitting 9-10. For this purpose, the connecter eye has its perforation 32 somewhat enlarged soas to receive a sleeve insulator 33 formed 'on'a washer insulator flange 34. In other'words, the insulator 3334 is a bushing made of any suitable in sulating material such as'hard rubber or fibre. The insulation bushing 33-34 is first placed on the clamplegj8 with the washer flange 34 in engagement with the pipe seat 10, and then the bracket eye 30 is placed over the insulator. The bracket eye 30 and its attached parts are thereforepositively insulated'from the pipe seat lOand leg 8.-

After assembling the bracket eye 30 and insulator bushing 33-34 on'the grounding pipe clamp, an additional insulator,'in theform of a plate or washer 36, may beplaced over the metal eye 30 and over the gasket sleeve 33, whereupon a metal washer 37 is'placedover the threaded leg 8 and against the insulator parts. The bare end 38 of the'ground wire is now coiled around the leg-8 of the clamp and against the metal washer 37, thelatter being cup shaped and including a flange 39 if desired to make a closed space in which the wire-end 38 is coiled. Another washer '40 may be placed over the wire 38 and the nut 11 is then tightened up to anchor all parts together. 7

The metal bracket 24 and cable connecter is thus insulatedfro'm the ground pipe and also swivels about the leg 80f the ground clamp or fitting. Figure?) shows a face view of the metal contacting washer 40.adapted to be pressed toward the underneath metal washer 37, both of which are spaced apart by reason of the wire 38 placedutherebetween', and the two views, Figures 4and .5, illustrate one example of this combination swiveled and insulated cable connecter for ground fitting use. The two washers 37 and 40 provide a positive electrical connector mounted on the yoke legand electrically connected thereto buttinsulated from the bracket arm "24 and eye 30. Hence the inner end of the arm 24 carries a combination insulation and electrical connecter, the current from thewire W having a good conductive path through the washer 40 and nut 11 into theyoke 8.

Figure 6 shows a side elevation of a, modified form of cable connecter wherein the eye 30 rests against an insulation bushing 34 and underneath an insulation washer 36 and thus it is similar in form to the devices described in Figures 4 and 5. However, the eye 30 carries an arm 43. which may be turned up at 44 and perfogated at H to make a standard size hole to receive any suitable form of cable conneoten Thus I have illustrated one, type of cable connecter at 25 and another simple form of cable connecter at44. p The principle of the invention is susceptible to various forms of eonsiruction. The cable connecter arm 44 has its hole :H of the same size as an ordinary knockout in outlet boxes so that any cable connecter may be used.

- It is seen that one. operating means, such as the nut 11 performs all functions of gripping the ground fitting on a pipe, locking the pivot against'rotation, and making electrical connection between the ground wire and pipe P; and that the pipe seat 10 can be rotated about the clamp legs 8 and have any of the seat holes 13, 20 and 21 mounted thereon. .It is significant that the metal eye or swivel head 30 is clamped between two in sulator means 34 and 36, and that the wire I terminal 38 is clampled between two contact plates 37and 40. ence the metallic cable connecter 25 and its arm 24 and the swivelled eye 30, together-with the cable BX, are all positively insulated from the ground pipe P and the fitting 9-10 clamped and grounded thereon; but the ground wire W38 'is electrically connected to and thus grounded on the pipe and fitting.

The invention fills a need andenables one to safely use flexible metallic armored cable in ground wire installations.

What is claimed is: V

1. In a grounding fitting, a clamp having means to grip a ground conductorand make electrical connection therewith, anchorage means to engage and hold a ground wire protective covering, pivot means to adjustably attach the anchorage means to the clamp so that said anchorage means may be pointed in anydirection desired to conveniently tach the protective covering to the clamp, and an insulator associated with the pivot means whereby the'protective covering is insulated from the clamp. i

2.- In a grounding fitting, a ground clamp having means to grip a groundconductor and make electrical Connection therewith, anchorage means to engage and hold a ground wire protective covering, pivot means to adjustably attach the anchorage means to the clamp, an insulator mounted on the pivot means to insulate the protectivocovering from theground clamp,an electrical conductor extending thru the insulator to ground a wire on the clamp; and a single operating means to grip the clamp on a pipe, to ip the ground wire to the conductor, an? to lock the pivot means against motion.

3. In a grounding fitting, a clamp having means to grip a ground conductor and make electrical connection therewith, a cable an chorage means to attach a cable to the clamp, pivot means adjustably mounting the cable anchorage means to the clamp, means to electrically connectaground wire in the cable to the clamp, and means insulating the cable from said clamp.

4. In a grounding fitting, a clamp having 'means to grip aground conductor and ,make

electrical connection therewith, a cable anchorage means to attach a cable to the clam pivot means to adjust-ably mount the cable anchorage means to the clamp, means to electrically connect a ground wire in the cable to the clamp but to insulate the cable from said clamp, said last named means including a a swivel head clamped between two insulator means and a wire terminal clamped between two contact plates, and screw thread operating means to tighten the last named means.

5. In a grounding fitting, a ipe clamp having means to grip a groun ipe conductor and make electrical connect1on therewith, cable connector means to engage and hold a ground wire protective covering, means to adjustably attach the.

cable connector to the clamp, said pipe clamp including an operating means to work the clamp and to fix the adjustable means in finally locked position, insulatin means having two spaced parts associatec with the operating means, and the adjustable means being mounted between the spaced parts, and an electrical connector mounted on the insulator and also including two spaced parts between which a ground WII'B is gripped. r

6. In a grounding fitting, a clamp having means to grip a ground conductor and make electrical connection therewith including a -pipe seat and yoke having legs and nuts on the legs, anchorage means mounted-on one or the yoke legs to engage and hold a ground Wll'e protective covering, an insulator on the same leg to insulate the covering from the fitting, and an electrical connecter on the leg to ground a wire to said leg.

7. In a grounding fitting, a clamp having means to grip a ground conductor and including a yoke with threaded legs on which is mounte a pipe strap, a swivel e e on the yoke, a cable connector carried'by t e swivel eye, and nuts on the legs to grip the swivel eye; on the clamp and to ground the clamp on the conductor. y 8. In a rounding fitting, a pipe clamp having a disk which is grooved across its center a number of times at different angles to form pipe seats of different sizes, a number of holes in the disk, a yoke having legs thru theholes, an insulator mounted on one of the legs and engaging the disk on the face thereof opposite the grooved seats, a cableconncctor mounted on the insulator, an electrical connector mounted on the leg adjacent the insulator and to which a ground wire is connected, a nut on eachleg to grip the pipe clamp on a ground conductor and to fasten the cable connecter to the fitting and to render effective the electrical connector.

9. In a grounding fitting, clamp means to ground on a pipe, an arm mounted on the clamp means, ac-able connector carried on one end of the arm, an electrical connector carried on the other end of the arm where the latter is mounted on the clamp means to connect a ground Wire from a cable secured in the cable connector, and insulating means insulating the arm from the clamp means.

10. In a grounding fitting, clamp means to ground on a pipe, an arm pivotally mounted on the clamp means, a cable connector carried on one end of the arm, an electrical connector carried on the other end of the arm where the latter is mounted on the clamp means to connect a ground wire carried by a cable secured in the cable connector to the clamp, insulating means insulating the arm from the clamp, and a single nut to lock the arm against pivotal motion after the latter is adjusted in relation to the pipe, to render eifect-ivethe electrical connector, and to Work the clamp means.

I 11. 1n a pounding fitting, clamp means to electrically ground on a rounded conductor, and a bracket mounted on the clamp means and including means at one end to attach a cable thereto and means at its other end to pivotally mount the bracket on the clamp means, 'said last means includinga pivotal insulator. and swivel eye to insulate the bracket from the clamp means, an electrical connecter included in and extending thru wire protective covering, pivot means to adjustably attach the anchorage means to the clamp so that said anchorage means may be pointed in any direction desired to conveniently attach the protective covering to the clamp, an insulating bushing slidable and rotatable upon the clamp and having a flange projecting therefrom, the pivot means being received upon the bushing and one side engaging the flange, an insulating washer slidable upon the bushing and engaging the other side of the pivot means, and a single operating means upon the clamp to grip the clamp on a pipe and to lock the pivot means.

13. A grounding system comprising a grounding fitting including clamping means to secure the grounding fitting to a grounded conductor, and anchorage means to secure an armored cable to the grounding fitting, an armored cable secured at one end to the anchorage means and carryinga ground wire electrically connected with the grounding conductor, and insulated means between the anchorage means and the clamping means thereby breaking electrical connection therebetween.

14. A grounding system comprising a grounding fitting including clamping means to secure the grounding fitting to a grounded conductor, and anchorage means to secure an armored cable to the grounding fitting, an armored cable secured at one end to the anchorage means and carrying a ground wire electrically connected with the grounding conductor, the other end of the armor of the armored cable being electrically connected to the ground wire, and insulating means between the anchorage means and the clamping means thereby breaking electrical connection therebetween.

15. A grounding system comprising a grounding fitting including clamping means to secure the grounding fitting to a grounded conductor, and anchorage means to secure an armored cable to the grounding fitting, an armored cable secured at one end to the anchorage means and carrying a ground wire secured to and electrically connected with the clamping means, the other end of the armor of the armored cable being electrically connected to the ground wire, and insulating means between the anchorage means and the clamping means thereby breaking electrical connection therebetween.

16. A grounding device comprising a rigid member having a seat portion for engaging a grounded conductor and having an opening arranged at each side 01' the seat portion, a U-shaped member for encircling the grounded conductor and havlng the ends of its branches extending through the 0 enin'gs in the first member, a third member liaving an annular portion for receiving the end of an electrical conduit and having a portion overlapping one end of the first member and being provided with a passage for receiving one branch of the U-shaped member, the U- shaped member having means for clamping the first and third members together in any of a plurality of angular ositions and for clamping the first mem Jer against the grounded conductor.

In testimony whereof I afiix In si ature.

STEPHEN N. BUG A AN.

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