US3188597A

US3188597A - Terminal device

Info

Publication number: US3188597A
Application number: US206948A
Authority: US
Inventors: Prescott K Turner
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1962-07-02
Filing date: 1962-07-02
Publication date: 1965-06-08
Anticipated expiration: 1982-06-08

Description

June 8, 1965 A Y P. K. TURNER TERMINAL DEVICE Filed July 2, 1962 United States Patent 0 pas 3,188,597 'IERMlNAL DEVICE Prescott K. Turner, Fairfield, Conn., assigner to General Electric Company, a corporation of New Yer-lr Filed .lniy 2, 1952, Ser. No. 2%,943 1 Claim. (Cl. 339-14) The present invention relates to electrical terminal devices, and is particularly applicable to the type of electrical terminal devices which have flexible ground-ing leads extending outwardly therefrom.

Terminal devices having flexible grounding leads have seen widespread use in cordsets for various appliance applications, such as, for example, in electric washing machines, air conditioners and dishwashers. For these applications, it is important that such devices be readily installable, and also of safe and reliable construction. PriorV art devices of the variety referred to have been found, in general, to be relative.y expensive to manufacture. Accordingly, an important object of the present invention is to provide an improved cord terminal device which includes a flexible grounding lead and is readily and economically manufacturable.

An additional object of this invention is .to provide an improved terminal device for a cord wherein a flexible grounding lead is arranged in such a manner that it prohibits the possibility of short circuiting.

A further object of my invention is to provide an improved cord terminal device which may be readily mounted in a supporting panel to provide an effective strain relief and a terminal block for the ends of associated conductors.

ln carrying out my invention, in one form thereof, I have provided a terminal device which is attached to one end of an electric oord. The conductors of .this cord are of substantially the same length and they enter into a molded insulating body from one end wall thereof. A pair of spaced apart contact prongs extend outwardly from another end wall of the body and are connected to the bared ends of a pair of associated conductors of the cord within the body. In this arrangement, to provide an improved means for grounding the device, a third conductor of the cord is looped over within the insulating body so that a flexible portion thereof extends outwardly from the wall of the body through which the conductors enter. The bared end of this flexible portion has an annular grounding contact connected thereto. The iiexible portion of the third conductor and the grounding contact are of such a length that the grounding contact is unable to engage the Contact prongs, thereby prohibiting the possibility of the grounding contact short circuiting with the contact prongs. In addition, since conductors of substantially the same length are utilized, there is no Waste in cordage involved in preparing the conductors for attachment to the insulating body of the connector. Y

Further aspects of my invention will become apparent hereinafter, and the specification concludes with a claim particularly pointing out and distinctly claiming the subject matter which I regard as my invention. The invention, however, as to organization and method of utilization, together with further objects and advantages thereof, may best be understood by reference to the following description when taken in conjunction with the accompanying drawing, in which:

FIG. l is a side elevation view partially in full and partially in section, of an improved terminal device embodying [one form of the present invention, the device being mounted in a suitable supporting panel;

FIG..2 is a front view of the improved terminal device j posed grounding conductor Ztl therebetween.

ICC

FIG. 4 is a perspective view of the device of FIG. 1;

FIG. 5 is a sectional view taken generally along the lines 5-5 of FIG. l, with the screw removed;

FIG. 6 is a side elevation view partially in full and partially in section, of an improved panel mounted terminal device embodying my invention, in alternate form thereof; and

FIG. 7 is a front View of the device of FIG. 6.

Referring iirst to'FIGS. 1-4 of the drawing, there is illustrated an electric power cord it), and a terminal device or cord connector l2 (FIG. 2) having a pair of contact prongs or blades le for making engagement with the female contacts of a suitable appliance (not shown). The device l?, and the illustrated portion of power cord lll are located at one end of a cordset, the other end thereof including a plug for engagement with a suitable power outlet. The terminal device 12 is securely positioned on the panel lo of an appliance, and furnishes power to the appliance for operation thereof through power cord lil.

Considering now more particularly the structure of terminal device l2 and cord'lt, attention is initially directed to FIGS. 4 and 5. Cord 1li is a relatively flat or oval shaped three-conductor rip cord, and includes two outermost insulated circuit conductors i8 with a centrally dis- .The conductors' i8 and .Ztl are normally disposed in parallel relationship t-o each other. Each of the

conductors

18 and 20 includes a number of stranded wires (as shown in FIG. 5) which are insulated by the extrusion of a suitable thermoplastic insulating jacket 22 thereover, such as polyvinyl chioride. A very thin coating 24 of thermoplastic material covers conductor 2d within jacket 22, its function being tol provide a relatively permanent identification means which will not tend to fray or wear off when the center conductor Ztl is exposed after the separation of the two outermost circuit conductors 13. It is a requirement of the National Electrical Code that the grounding conductor, such as the one disclosed herein shall be readily identiable by a green color, and covering 24 is therefore so colored.

For effectively supporting and insulating the connections between conductors It and their associated contact blades a4 and providing a simplified strain relief therefor, as shown in FIGS. 1, 4, and 5, an angularly shaped insulating body 32 has been provided. More particularly, the body 32 has an angularly shapedV profile ((*FIG 1), and from upper end 3i? to lower end 34, it includes section 36, through which the contact prongs i4 extendV outwardly, and section 395 from which the grounding conductor 2li extends outwardly. The arrangement of grounding conductor Ztl in the insulating body 32 helps to prohibit the possibility of short circuiting and also helps to reduce the cost of manufacturing the terminal device, as shall become apparent hereinafter.

To secure the device l2 to panel 16 in a simple and expeditious manner, an aperture dil is formed through section 38 of the insulating body 32. (See FIG. 1.) A screw 42 is extended through the aperture 40 from the right side thereof, viewing FIG. 1, and the outer end of the screw is threaded into engagement with a tapped opening 44 of panel 16 to fasten the connector insulating body 32 thereto. In the illustrated embodiment, a washer 46 is placed on screw 42 between its hexagonal head and the adjacent surface of section 38. To prevent rotation of the device l2 with respect to the panel 16, as shown in FIG. 1, the contact blade section 36 of body 32 is extended through an aperture 48. In the illustrated embodiment of FIG. 1, aperture 48 is formed in a transverse` wall Vdisposed in angular relationship to spaced apart parallel walls 16a and lob of the panel 16.

Turning now to a detailed explanation of an important amasar aspect of the present invention, attention is directed to FIGS. 4 and 5. In accordance with the present invention, the contact blades 14 extend outwardly from end 30 of insulating body 32. Grounding conductor 2G extends outwardly from the opposite end 34 of body 32 and is arranged in relationship thereto to prohibit the possibility of short circuiting the grounding conductor to the blades 14. In manufacturing the terminal device 12, the conductors 18 and Ztl are all cut to substantially the same length. Thus, if grounding conductor 2t) were disposed alongside of conductors 1S, within body 32, and the free end of conductor 20 thereupon extended in the same direction as the free ends of conductors 1S, the position which conductor 20 might then assume is shown by the phantom lines in FIG. 5. By utilizing conductors which are all of substantially the same length, the length of grounding conductor which is required for each terminal device 12 is the same as the length of power conductor required, thereby obviating the burdensome cost of scrap which has been inherent in many of the prior art devices wherein the grounding conductor has a greater length than the circuit conductors. The terminal device 12 of the present invention, may thus be manufactured at an economical cost.

As shown in FIGS. l and 4, the grounding conductor 20 enters the lower wall 34 of insulating body 32 in parallel side-by-side relationship with circuit conductors 1S. The bared ends of the outermost circuit conductors 1S are crimped to the inner ends of blades 14 (FIG. 5) and disposed within body 32 near upper end S) thereof. However, grounding conductor 2@ is looped over and doubled back toward itself at (FIG. l) within the body 32 near bottom end 34 and arranged so that it extends outwardly from end 34 in a direction opposite to the direction in which the contact prongs 14 face. The doubled back portion 50 of the conductor 2t) is encapsulated by the molded insulating body 32. A ring-shaped contact 54 is crimped to the bared free end of grounding conductor 2?. The combined length of exposed flexible grounding conductor 20 and contact 54 is such that contact 54 cannot reach either of the contact prongs 1.4 at the other end of the insulating body. In View of the length, and looped arrangement of grounding lead 20 and the positioning thereof in device 12., the possibility of short circuiting between the grounding conductor 2G and the circuitV conductors 18 is prohibited. It will thus be seen that the improved terminal device 12 is of extremely safe and reliable construction.

To connect/the grounding Contact 54 of the device 12 to lpanel 16, as shown in FIG. l, screw 56 is extended through the aperture of the ringshaped contact54 and engages tapped hole 5S of the panel 16. To preclude the possibility of short circuiting between the outermost ends of the contact prings 14, an elongated tongue-like insulating barrier 60 extends outwardly from end 3d of body 32. Barrier 60 is disposed between and generally parallel to the spaced apart contact prongs 14.

FIGS. 6 and 7 represent a modified form of my invention wherein terminal device 112 has been employed. For device 112, the same reference numerals have been employed to indicate connector parts and associated conductors which have heretofore been described for device 12. Parts of device 112 which have a modified structure in comparison to the structure of their correlative parts for device 12, but perform the same basic functions are identified by the same two reference numerals with the numeral 1 prefixed thereto.

The basic difference between terminal device 112 and device 12 resides in the fact that device 112 has Vits contact gong-s 14 facing angularly outwardly, or to the right of flat panel 116 (viewing FIG. 6), whereas the device 12 is constructed so that its contact prongs-14 face angularly inwardly or to the left of the panel 16 (viewing FIG. 1), and extend through the panel 16. The insulating body 132 of device 112. thus includes section 136 through which the contact prongs 14 extend angularly outwardly, and section 13S which is disposed in angular relationship to section 136. The grounding conductor 29 extends downwardly from end 134 of the insulating body 132 in the same manner as previously described for device 12 and is also fastened to the panel 116 in the same manner. Device 112 is fastened to the flat panel 116 by the extension of screw 42 through aperture 40 of the insulating body, the outer end of the screw 42 being in threaded engagement with the tapped hole 44 of the panel 116.

To prevent rotation of terminal device 112 in panel 116, a rectangular boss 161 is formed on the side of section 13S of the insulating body 132 which faces the panel 116. Boss 161 enters a suitable rectangular aperture 148 formed in the panel 116 and cooperates therewith to preclude any rotation of device 112 with respect to the panel after it is fastened thereto by means of screw 42.

In assembling the improved terminal devices of the present invention, the cord 10 with the two circuit conductors 18 and grounding conductor 20 is initially cut so that each conductor is separate for a distance and is of substantially the same length. The contact prongs 14 are thereupon crimped to the bared ends and adjacent insulation of conductors 18, and the grounding contact 54 is crimped to the bared end of grounding conductor 20. The conductors 13 and 20 are then positioned in the mold with the grounding conductor 20 looped over, as shown in FIG. 5, so that the free end of conductor 20 and its associated contact 54 faces in a direction generally opposite to thedircction of the free ends of the two circuit conductors 18 and their associated contact blades 14. The insulating body is then molded around the connections between circuit conductors 1S and prongs 14 in the manner illustrated in FIG. 5, with the grounding conductor 20 extending outwardly from the bottom end of the insulating body through which the conductors of cord 10 initially enter.

It will now therefore be seen that my new and improved cord terminal device as illustrated herein provides for the novel arrangement of a exible grounding lead and reduces the cost of manufacture of the device while also prohibiting the possibility of short circuiting between the grounding contact and the main circuit contacts. It will further be understood that the terminal device of the present invention maybe readily mounted in a supporting panel to provide a strain relief and a terminal block for the ends of associated conductors.

While in accordance with the patent statutes, I have de scribed what at -present are considered to be the preferred embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from my invention, and I, therefore, aim in the following claim to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What I ciairn as new and desire to secure by Letters Patent of the United States is:

For use with a panel, a cordset comprising a cord and an electrical terminal device adapted to be supported by the panel, said device including a molded insulating body attached to one end of a cord, said cord including at least three conductors of substantially the same length and entering into said insulating body from a rst end wall thereof, a pair of spaced apart power contacts facing outwardly from a second end wall of said body, said power contacts being connected respectively to the bared ends of two associated power conductors of said cord within said body, the other of said three conductors of said cord being doubled back upon itself within said body and including an external portion extending outwardly from said first end wall of said insulating body, said doubled back portion of said other conductor encapsulated by said insulating body and held in fixed relation to said two associated power conductors and contacts by said insulating body, a grounding contact connected to the free 5 6 end of the external portion of said other conductor, said 1,881,883 10/ 32 Noble 339-125 external portion and grounding contact being of such a 2,207,477 7/40 Blackmon 339-66 length that the grounding contact is unable to engage said 2,654,077 9/53 McLoad 339-148 X power contacts, thereby prohibiting the possibility of said 2,723,330 11/55 Howard 339....10 grounding contact short circuiting with said power con- 5 2,869,091 1/59 Robards 339 192 tacts, and fasteningmeans for securing said terminal de- 2,986,718 5 /61 Bender 339 14 vice to the panel.

References Cited bythe Examiner FOREIGN PATENTS 434,142 9/ 26 Germany.

UNITED STATES PATENTS 10 207,092 11/23 Great Britain.

286,963 10/83 Reed 339--148 1,157,026 10/15 Meschenmoser. JOSEPH D. SEERS, Primary Examiner.