US2260121A - Wiring device - Google Patents

Description

Oct. 21, 1941. B, MILLER 2,250,121

WIRING DEVICE Filed Nov. 27, 1939 WIRING DEVICE James B. Miller, Webster Groves, Mo., assignor to Mines Equipment Company, St. Louis, Mo., a corporation of Missouri Application November 27, 1939, serial No. 306,217

' 3 Claims.

This invention pertains to wiring devices which may be used for running temporary electric circuits. In many places, as for instance in mines, it is often desirable to run a temporary circuit for lighting or the like and to provide in such circuit a plurality of outlets or taps whereby currentmay be taken from the circuit for local purposes in the mine. The cables used in running such temporary circuits are subject to a great deal of rough treatment and it is desirable, therefore, to provide a very robust construction particularly at the outlets.

One of the objects of this invention, therefore, 1s to provide such a wiring device and particularly an outlet whereby connection may be made to such a circuit which shall be simple to manufacture and which is capable of withstanding a. great deal of abuse.

As such circuits are frequently changed from place to place, the flexible cables used therefor are subject to repeated bending. found that where a plug socket outlet is connected into such a cable, the continual bending of the conductor wires causes the saine to break at the point Where soldered joints are made to the plug contacts.

Another object of this invention, therefore, is to provide a construction which will permit flexure of the conductors or cables without affecting any fixed or soldered joints.

Another object is to provide a construction for such an outlet connection whereby any tensile stress put upon the outlet portion by tension on the cables is taken up without subjecting the conductor wires to such stress.

Another object is to provide such a wiring de vice with hanger means whereby it may be secured to suitable supports by temporary or permanent fastenings.

Further objects will appear from the following description taken in connection with the accompanying drawing in which:

Figure i is a sido view of a wiring device ernbodying this invention.

Figure 2 is a top view of the outlet portion as arranged before the iiexible insulating housing or covering has been molded thereon.

Figure 3 is a top view of Figure l with part of the hanger shown in section.

Figure 4 is a side-view similar to Figure 1 'out i somewhat enlarged, with the insulating housing shown in section so as to illustrate the interior construction; Y

Figure 5 is a section on line 5,-5 of Figure 4; .and

It has been Figure 6 is a sectional view oran end socket constructed `in accordance with this invention.

The cables used for Stringing temporary circuits of this kind are usually made up in continuous lengths with outlets at spaced intervals thereon so that current may be taken from the circuit at such outlets as for lighting purposes, or the like. These cables may be made up in any length and may be arranged for` coupling one to another so as to extend the circuit for any desired distance.

Figure 1 shows a portion of such a cable at one of the outlets, which is indicated generally at l. This may be constructed in the form of a plug socket which may have one Ior more sockets adapted to receive a connecting plug for making a temporary connection to the circuit. The embcdiment selected for illustration in the drawing shows a two-conductor cable and the outlet l has two sockets, one connected to each of the conductors. These sockets may be arranged to receive the plug contacts 2 of any kind of currentconsuming device, such as the lamp socket 3, or similar plug contacts arranged at the end of a second cable forming a b. inch circuit.

In the embodiment illustrated, plug sockets 4 of any suitable type provide Contact elements for making connection to the branch circuit by receiving plugs such as 2. These may be of different sizes so as to be insert-able at the sockets 4 in onlyone position in order to preserve a predetermined poiarity in the branch circuit. In the embodiment illustrated, the sockets 4 are constructed of tubular members slotted longitudnally and laterallyreis shown in Figure 4, s0 as to substantially out away a section of the tube, thus rendering the latte?.` flexible with respect to the tube, and this may then be resilientiy cornpressed by a coil spring 5 slipped over1 the end of the slotted tube. The upper ends oi' the socket members 4 may be reduced in diameter, as shown in dotted lines in Figure Il, so as to provide a re` duced neck about which the cable conductor may be looped as will now be described.- r

The main circuit cable E may be of the type having two ilexible conductors l and E insulated from one another, and a pair of tension 3 and ill running along the cable to taire up the mechanical tension therein. These cords are usually ci soit material and are laid alongside of the conductors 'i and 8, as shown in the end views in Figure ci, and the entire assembly covered with a rubber sheath il.

In making the outlet l, a portion ci thesheath ls cut away for a proper length, as illustrated in Figure 2, so as to expose the conductors l and 8 and the cords 9 and I0. In Figure 2 the cord 3 is shown cut away and the cord III is omitted entirely in order to more clearly illustrate the arrangement of the conductors 'I and 8. In the actual construction, however, these vcords are not cut. In order to make connection between the conductors 'I and 8 and the sockets 4, each conductor is stripped of its insulation for a short length, as indicated at l2, and the bare portion is then looped around the socket member 4l at the reduced portion thereof. The loop is preferably executed by turning the conductor inwardly around the element 4 and then outwardly to continue along a cable. This places both ends of the loop on the outside, as shown in Figure 2. The opposite side, or middle, of the loop is then permanently connected to the element 4 by a fixed connection, such as the soldered joint indicated at I3. By xed connection, as used in this specification and the appended claims, is meant such a connection as may be made by soldering, welding, or even clamping so as to render the two connected conductors immovable with respect to each other. It will be seen from Figure 2 that this method of connection provides an extended portion of the loop of the conductor between the xed connection I3 and that portion of the conductor which continues along the cable. With this arrangement any lexure of the conductor I or 8, due to exure of the cable 6, is taken up in this extended portion of -the loop before reaching the fixed connection I3, and there will be practically no relative movement between the conductor 'I and the contact 4 at the connection I3. This is a great advantage as it eliminates the principal cause of failure by breakage of the conductor at the xed connection. Accordingly, this device may be subjected to practically any amount of flexure without danger of breaking the conductors at the soldered joint.

The operation of looping the conductors around the contact elements 4 tends to shorten the cable E by the amount taken up in the loop. Since the cords 9 and I0 have not been cut this produces a slack portion in each conductor. portion is then formed into a loop which is also looped about one of the contact elements 4. The loops of the cords 9 and I0, however, are placed around the elements 4 at points of larger diameter than the reduced necks about which the conductors I and 8 are looped. Accordingly, the loops in the conductors take up a slightly greater length of cord than is taken up in the conductors I and 8 by their loops. Accordingly there remains slightly greater slack in the conductors than in the cords and, consequently, any tension coming upon the iinished device will be taken by the cords rather than by the conductors.

Figure 4 illustrates the manner in which the cords are looped about the Contact elements. When the connections have been made as described, a housing or covering I4 of exible insulating material, such as rubber, is molded about the entire assembly including the contact elements 4 and the looped portions of the conductors and the cords, leaving openings I5, of course, to permit the entry of the plugs 2 into the sockets 4.

In order to provide for adequately supporting the circuit at the outlet I, a hanger I6 may be formed on the housing I4 during the molding operation. In order to strengthen this hanger,

a web Il of fabric is molded into the hanger Il?.l This may be placed as shown in Figure 5, being This slack doubled at that portion within the hanger IS and the two layers separated and carried around the outside portion of the housing I4. The hanger I6 may be provided with a suitable opening I8 to receive a tie or other fastener for supporting the circuit. Auxiliary stiffening webs I9 may also be provided and these may be provided with fastener-receiving openings 20.

In the embodiment of Figure 6, the housing I4 is formed at the end ofthe cable II and the openings I5 and the elements Il are positioned for insertion of the plug from the end of the housing,

It will be seen, therefore, that this invention provides a construction for a Wiring device of this character which is simple to make and which will provide a durable device in service. The ar rangement of the loop in the conductor and the xed connection I3 at the middle of the loop so as to provide a substantial portion of the loop between that connection and the point where lexure usually comes upon the device is effective in preventing such flexure from being imposed upon the conductor at the xed connection and accordingly ample flexibility is provided in that part of the conductor so 'that breakage due to such exure is substantially eliminated. It will also be noted that the conductor is supported interiorly of the loop by the rounded shank of the contact element at that portion of the conductor between the xed connection and the beginning of the loop. This prevents any possibility of kinking and also insures a gradual exure outwardly by unwinding the conductor progressively from around the Contact element. Accordingly, this arrangement insures the maintenance of a loop of substantial radius in which flexure is conn'ed to those portions shaped from the fixed connection. The looping of the cords is so arranged as to shorten them relatively to the conductors so that they are effective in taking up tension put upon the cable 6 and in relieving the conductors of all stress due to such tension. The entire structure is then housed in a exible rubber housing adapted to protect the parts and retain them in their proper relative positions while at the same time being capable of withstanding an unlimited amount of rough treatment without rendering the device inoperative. When the housing at the entry openings I5 is formed, as illustrated in Figure 4, to match the end portions of the plug device 3, a water-tight joint may be madebetween these parts. The springs 5 may be so proportioned as to provide a substantial pressure between the elements 4 and the plugs 2 so that the latter are securely held when' once inserted. Accordingly, such a circuit may be allowed to lie on the ground, or to be temporarily suspended upon any sort of structure and will be proof against injury or disarrangement even under'rough handling.

While this invention has been described as embodied in a unitary device, it will be understood that individual features or sub-combinations thereof may be useful by themselves without reference to other features or the complete combination. It is understood, therefore, that the employment of such individual features or subcornbinati'ons is contemplated by this invention and within the scope of the appended claims. It is further obvious that various changes in the details of construction may be made within the scope of the appended claims without departing from the spirit of this invention, and it islto be understood that the invention is not limited to the specic details shown or described.

Having thus described the invention, what is claimed is:

1. An electrical connector of the character described, comprising, a cable having a flexible conductor, a contact element connected to said conductor, a stripped portion of said conductor being looped entirely around said element at a rounded portion thereof and connected thereto by a fixed connection so as to leave a free portion of the loop supported interiorly by said rounded portion of said element, and means providing a exible housing for said connected portion of said conductor and said element at said connection.

2. An electrical connector of the character described, comprising, a cable having a flexible conductor, a contact element connected to said conductor intermediate its ends, a stripped portion of said conductor being looped entirely around 20 said element without being severed and connected thereto by a fixed connection at the middle part of the loop only so as to leave the ren-airing porqq tion of the loop relatively 'free for lie ure, e -fmeans providing a flexible housing s d c nected portion of said conductor and said elem., it at said connection.

3. An electrical connector of the character de scribed, comprising, a cable having a ilexible conductor and a tension cord, a contact element connected to said conductor intermediate its ends, a stripped portion of said conductor being looped entirely around said element without being severed and connected thereto by a xed connection at the middle part of the loop only so as to leave the remaining portion of the loop relatively free for lexure, and said cord also being looped en tirely around said element so as to take up the slack produced by looping said conductor, and means providing aexible housing for said connected portion of said conductor and said element at said connection.

JAMES B. MILLER.

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