US3366917A - Plug contactor - Google Patents

Description

Jan. 30, 1968 KAROL 3,366,917

PLUG CONTACTOR Filed Oct. 15, 1965 United States Patent ABSTRACT OF THE DISCLOSURE A flexible insulating shroud for a plug contactor wherein the shroud has a series of serrations to facilitate manual grasping and has a pair of conical sections to provide strain relief.

This invention relates to plug contactors of the type used, for example, in plugboards for automatic computers, tabulators, accounting machines and the like for completing selected electrical circuits to control the operation of the machine as desired, and more particularly to a new and novel shroud or jacket for such contactors.

In normal use plug contactors are subjected to a great number of insertions and withdrawals from a plugboard. During the withdrawal of such contactors from a plugboard it is desirable to have the operator grasp the shroud proper to effect the withdrawal. However, in order to effect a more rapid operation, the operators will frequently merely pull on the wires leading to the plug contactors and effect the withdrawal in this manner. So long as the wires are pulled at right angles to the plugboard, there is no problem; however, as often results, the wires are pulled at a sharp angle to the board and, therefore, create great bending stresses in the region where the wire connects with the contactor. If this procedure is repeated a sufiicient number of times, there is the possibility of the wire fraying and thus destroying the electrical connection.

It is therefore an object of this invention to provide a new and improved shroud for plug contactors whereby the possibility of fraying the wires is materially reduced.

Another object is to provide a shroud having means which facilitates grasping the contactor directly for insertion or withdrawal.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purpose of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings, in which like reference numerals refer to like parts:

FIGURE 1 is a perspective view of a plug contactor showing a preferred embodiment of the present invention,

FIGURE 2 is a side elevational view of the plug contactor shown in FIGURE 1, and

FIGURE 3 is a side elevational view similar to FIG- URE 2 but showing an alternative form of shroud.

The plug contactor comprises an outer sleeve member 2, as seen in FIGURE 1, and a nose portion 4 terminating in a nose member 6. A pair of radially extending latch portions 8 extend from the outer sleeve and are positioned to be engaged behind a rearwardly directed face of a plugboard into which the contactor is connected. A wire conductor 10 is connected to the plug 3,366,917 Patented Jan. 30, 1968 member and an insulating shroud or jacket 12 of plastic or the like surrounds the connection. For a more complete disclosure of the manner in which the wire conductor is connected to the plug member, reference is made to US. Patent No. 3,134,633 issued May 26, 1964, and assigned to the assignee of the instant application.

Referring to FIGURES 1 and 2 the shroud 12 is seen to comprise a cylindrical portion 14 which surrounds that portion of the plug and Wire conductor where the connection has ben effected. Integrally formed with the cylindrical portion 14 is a first tapered section 16, said tapered section extending substantially beyond the end of the forward part of the plug contactor. A series of serrations 18 are formed in the shroud in order to facilitate grasping of the shroud for inserting the plug into or withdrawing it from the plugboard. It is to be noted that the diameter of the shroud adjacent the serrations 18 is substantially less than the outer diameter of the cylindrical portion 14. Therefore, not only does the serrated portion serve the function of facilitating grasping but further provides a reduced diameter section wherein bending of the shroud can readily occur. If the shroud was ended at this point, it can be seen that the majority of the bending of the shroud during pulling on wire conductor 6 at an angle to the plugboard would be confined to that area immediately adjacent to the serrations. In so confining the area over which the bending of the wire takes place, there results a sharp radius which is objectionable in that sharp radii produce extreme stresses which are quite likely to damage the wire conductor. To avoid this situation, a second tapered section 20 is provided, which section terminates in a portion of substantially reduced diameter. By providing this second tapered portion, the radius of curvature of the bending of the wire is significantly enlarged and the stresses on the wire are distributed over a substantial length of wire. The wire conductor 6 can now be bent and pulled an indefinite number of times without resulting in any damage to the conductor.

FIGURE 3 shows an alternative embodiment of the invention wherein the shroud 22 comprises a cylindrical portion 24, identical to cylindrical portion 14 previously described, and a long tapered portion 26 having a series of serrations 28 disposed therealong. As can be seen from the figure, the serrations 28 decrease in size to follow the angle of the taper 26. In this embodiment it can be seen that the serrations 28 provide a grasping means over a substantial length of the shroud. If the wire conductor 6 is pulled or bent at a substantial angle to the plugboard, the bend will be taken up over the entire length of taper 26 and serrations 28 thereby establishing a considerably large radius of curvature with the result that the bending stresses are spread over a substantial portion of the wire. As in the previous embodiment, the conductor 6 can now be bent and pulled an indefinite number of times without damage to the conductor.

It can therefore be seen that the objects of the invention have been achieved in that a shroud for a plug contactor has been produced which will permit the conducting wire to be pulled at any angle to a plugboard without any danger of damage to the wire.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

I claim:

1. In a plug contactor wherein a wire conductor is connected to a plug element, a flexible insulating shroud comprising a cylindrical portion surrounding the connection between said plug element and said conductor, a first strain relieving portion extending from said cylindrical portion and being a frustum of a right circular cone, a serrated portion extending from said first strain relieving portion for facilitating manual grasping of said plug contactor, said serrated portion comprising a plurality of annular rings of substantially equal diameter, said diameter being less than the external diameter of said cylindrical portion and greater than the minimum external diameter of said first strain relieving portion, and a second strain relieving portion extending from said serrated portion and being a frustum of a right circular cone, said second strain relieving portion having a maximum and minimum external diameter smaller respectively than the maximum and minimum external diameters of said first strain relieving portion and being of greater axial extent along said conductor than said first strain relieving portion.

References Cited UNITED STATES PATENTS 15 RICHARD E. MOORE, Primary Examiner.

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