US1663711A - Electrical apparatus - Google Patents

Description

March 27, 1928.

J. M. LALER ELECTRI CAL APPARATUS Filed March 23, 1925 INVENTOR Jea/ wf/M mele Patented Mar. 27, 1928.

UNITED STATES PATENT OFFECE...

JEROME M. LALER, OF BURLINGAME, CALIFORNIA., ASSIGNOR TO CEAS. CORY & SON,

' INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NW YORK.

ELECTRICAL APPARATUS.

Application led March 23, 1925. Serial No. l17,680.

This invention is an improvement in electrical apparatus, and more particularly in terminal boxes or receptacles and connecting plugs for cooperating therewith.

For convenience in tapping electrical circuits it is usual to interpose in the circuit ter.- minal boxes or receptacles in selected locations, the apparatus to be connected having connecting plugs, which carry circuit terminals designed to cooperate with those of the box, to electrically connect the apparatus with the source of current supply.

ln marine work especially, the terminal box or casing should be fluid tight, and this condition should obtain when the plugs are removed, as well as when they are in place, in order that the connections be protected, and water be excluded, at all times. Hence mechanism to provide a fluid tight joint between the plug and the receptacle is necessary, as well as other mechanism to close the opening or socket through. which the plug engages, when the plug is withdrawn. Furthermore, such mechanism should not only be fool-proof, so far as possible, but should be proof against inadvertence resulting in partial or incomplete insertion of the plu In adition to such general objects as the providing of a construction of box or casing which will be fluid-tight when the plug is in place as well as when the plug is removed, and the provision of a mechanism for closing the opening or socket of the casing which is automatic in its action and normally urged to closing position, so that when the plug is removed the opening is automatically closed without the necessity of attention by the operator or attendant, one of the prime objects of my invention is the provision of a plug and socket of such interrelated construction that the functioning of the plug as a circuit-maker is dependent upon the establishment of a water-tight connection between the plug and the box.

Another object is the provision of a simple and inexpensive construction of plug and casing so constructed and arranged that the plug in addition to its connecting function also serves as a switch, for engaging and l disengaging the circuit terminals.

To the accomplishment of the foregoing and such other objects as may hereinafter appear, the invention consists in the construction and novel combination of parts fully described hereinafter, illustrated in the 'accompanying drawings, and pointed out 1n the claims appended hereto, it being understood that various changes in the form, p1.'o1')ortion, size and minor details of construction, Within the scope of the claims, may be resorted to without departing from the spirit of the invention.

Fig. 1 is a longitudinal'section of the improved casing and plug, with the plug in position to function as a connector.

Figs. 2 and 3 are sections on the lines 2-2 and 3-3, of Fig. 1.

ln the present embodiment of the invention, a receptacle or casing is provided including a body 1, of suitable shape and size, and a detachable cover 2, held to the casing body bylmeans of screws 3 or the like. A gasketA' is arranged between the cover and theA body, for making a water tight joint, and the cover has a transversely extending socket or nipple 5 providing an inlet opening for the plug to be described.

Blocks 6 of insulating material are secured to opposite side walls of the casing, and contact elements 7 in the form of strips of conducting material are supported by the blocks, being'conneeted thereto by screw bolts 8 as shown. The contact elements extend on opposite sides of the socket 5, and

the free ends are offset inwardly toward each other as shown.

At the opposite end'of each contact element 7 from the inwardly oiisetportion a lug 8 extends inwardly toward the middle of the casing, and each of these lugs has a screw 9 threadedly engaged therewith, for connection with the leads 10 of the electrical circuit which is to supplycurrent to the apparatus engaged with the plug.

The casing may be tapped at any suitable point, to provide an inlet opening for the circuit leads, preferably on the ends, which are reinforced as indicated at 11, to provide a sufficient hold for the threaded end of a conduit 12. The circuit leads 13 are carried by a cable which passes through the conduit as shown in Fig. 1.

The plug comprises a substantially cylindrical body 14 having its outer end reduced. The cable 15 carrying the outlet leads 16 passes through a bushing 17, preferably of soft rubber, and a cap 18 is threaded onto the reduced end of the body 14, engaging the cap', and acting to expand said bushing when the cap is tightened thereby to effectually seal the space between cable and body.

As Ishown in Fig. l. the bushing 17 tapers in both directions. and the outer end of the reduced portion ot the body 14 is roamed to tit one end ot' the bushing. rlhe bushing extends beyond the end ot the body, and the cap which hasl an opening 19 for the cable, is arranged to compress the bushing against the reamed portion ot' the body.

The body of the plug is of a size to [it easily within the nipple or socket 5, and it i connected to the socket, in a water ti jht manner, by inea-ns of a collar 20 having threaded engagement with the socket, and engaging an annular shoulder or ledge 21 on the body. A gasket or packing 22 is arranged between t-he collar and the end of the socket, against which the rib 21 may be forced by the collar to `torni a seal and a water tight connection at this point.

A block 23 of insulating material is held centrally of the socket, by means of a cross pin 2t, and contact elements 25 are secured to the lower end otl the block, the said block extending beyond the inner end of the plug body, and beyond the inner end of the socket when the plug is in place.

As shown more particularly in Figs. 2 and the block 23 at its lower end is provided with a cross head 26, and the contact elements 25 are extended around the ends of the head, so that each member laps upon two sides and one end of the cross head. The length of the cross head, including the laps ping contact elements is greater than the normal distance between the Contact elements 7, while the width of the head, including the contact elements 25, is considerably less than lnich distance.

Since. the contact elements 7 are equally .spaced from the axis of the plug, it will be evident that when the plug is introduced with the head 26 extending longitudinally ol the casing, there will be no cooperating engagement between the contact elements 25 and 7 The plug must be moved angularly a distance of 90 degrees, to bring the head transverse to the casing before such cooperative engagement obtains. Means is provided in connection with the socket for preventing introduction or removal of the plug` except when the contact elements 25 are out of cooperative relation with the elements 7. Said means is an opening 27 at the inner end of the socket, of rectangular shape, and of a size approximately that of the head plus the strips 25. The opening 2T is ot a size, and shaped to permit the passage ot the head, when it extends longitudinal to the casing, and it cannot pass into or out of the casing in any other position.

This collar 20 and its restricted movement on the body portion of 'che plug constitute nceamil an important feature ol my invention. By reference to ltigs. 1 and 3, it will be noticed that the relative movement of this collar 20 is limited to the distance between the rib 21 and the lower end of the sleeve portion ot the collar 28. llt. will be noticed that the Space through which said collar r2O has movement. on the body port-ion of the plug is substantially less than the distance through which said collar must be threaded on the upper end of the socket, in order to permit oi a clearance between the crosshead 26 and the lower end ot' the socket.

It will be apparent, therefore, that when the plug is initially inserted in the socket, the thread at the lower end of the collar 20 will envage the thread at the upper end of the soc {et and check the operation of the insertion of the plug prior to clearance between the cross-head 26 and the lower end of the socket. Thus, in order to effect the desired electrical connection, it is necessary to screw said collar 20 down upon the threaded portion of said socket a sufficient distance to effect this clearance, and in so screwing said collar on said socket, a wat-ertight connection is established and must be established before the device as a whole will function.

The construction enables the plug to serve also as a switch, for connecting the branch circuit leads 16 with the supply circuit leads 13. Inserting the plug, and moving it over an angular distance of 90 degrees will make the desired connection, and the connection must be made with the box before the plug is used. For convenience in turning the plug, a collar 28 is secured to the plug body by means of the screw 29 or the like, the collar as well as the collar 20, and the cap 18, having knurled edges for convenience in manipulation.

In order to provide a seal and water tight closure for the inner end of the socket 5 when the plug is removed, a plate 30 is mounted at the inner end of the socket. The said plate is faced with a layer of packing material 31, and is slidably mounted at its ends on guide rods 32, which are threaded into nipples 33 uprising fromthe bottom of the casing body. Each rod is encircled by a spring 34 between the plate and the nipple, the springs normally urging the plate upward against the inner end of the nipple or socket to seal the same. Stops 35 in the form of cotter pins are provided at the tops of the rods, to limit the upward movement of the plate, and rubber washers 36 encircle the rods above the packing plate which is of rubber or like material.

The plu is rotatable in the socket, in order that t e connection may be made by angular movement of the plug through an are of 90 degrees, and in order to center the plug when itis inserted, the lower end of 1,eea,711

the plug 23 has an axial recess 37, which is designed for engagement by a centering pin 38 in connection with the plate 30. This pin may be a rivet as shown, passing through the plate 30 and the backing 31, and assisting to hold the backing to the plate.

A cover is provided for the socket when the box is not in use, that is when the plug is removed. The cover is in the form of a cap 39 threaded to engage the outer end of the socket and cap the same. The cap has a swinging connection with the cover 2 of the box, an arm 40 is pivoted to the box at 41, at one end of the arm, and to the cap at the other end, as indicated at 42. The arm is of a length such thatthe cap may be swung into axial register with the socket, and since the cap is pivotally connected with the arm, it may be turned to engage the socket or to release the same. The pivotal connections 41 and 42 are loose with respect to the arm 40 to permit the necessary movement of the cap in engaging and releasing the socket.

In the use of the improved box and plug, when it is desired to make connection at any selected box, the cap 39 is removed, and the plug is inserted. The inner end of the plug 23 engages and depresses the normally operative closure 30-31 for the socket, the said closure moving down between the terminals 7. The pin 38 centers the plug, and after the plug has been inserted, the collar 20 is turned down to make a water tight connection. When so connected, angular movement of the plug through an are of 90 degrees will connect the branch leads 16 with the supply leads 13. The plug must be inserted with the head 26 extending longitudinally of the box, and it must be securely connected to\ the box before it can function perfectly as a switch, or as a connector. Unless it is connected to the box, the springs 35 willpush it out of engaging position. As soon as the plug is released and Withdrawn, the closure 30-31 moves against the inner end of the socket sealing the same with a Water tight Seal.

I claim:

1. Apparatus of the class described, including a terminal box and a connecting plug, the plug having a cross head for connecting with the terminals, and the box and opening shaped to tit the cross head and with its axis at an angle to the position assumed by the plug when making connection, the box having a threaded nipple encircling the opening through which nipple the cross head must pass to enter the opening, and a collar on the plug for threadedly engaging the nipple to make a fluid tight connection, said collar abutting the end of the nipple before the cross head clears the opening and retaining the cross head in the opening until threaded down upon the nipple.

2. Apparatus of the class described, in-

cluding a terminal box and a connecting,

plug, the plug having a cross head for connecting with the terminals, and the box and opening shaped to tit the cross head and with its axis at an angle to the position assumed by the plug when making connection, the box having a threaded nipple encircling the opening through which nipple the cross head must pass to enter the opening, a collar on the plug for threadedly engaging the nipple to make a fluid tight connection, said collar abutting the end of the nipple before the cross head clears the opening and retaining tlie cross head in the opening until threaded down upon the nipple, and a normally operative fluid tight closure for the opening, opened and held opened by the 1nsertion of the plug.

Signed at Burlingame, in the county of San Mateo and State of California,this 11th day of March A. D. 1925.

JEROME M. LADER.

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