US2209038A - Electric contact - Google Patents

Description

July 23, 3940.. H, mm 2,209,038

\ .ELEC'I'RIC CONTACT Filed June 6, 1958 Patented July 23, 1940 UNITED STATES ELECTRIC Charles H. Rippl, Cleveland, Ohio, assignor to The Clark Controller Ohio, a corporation of Company, Ohio Cleveland,

Application June 6, 1938, Serial No. 212,055

4 Claims. (01. 267-1) This invention relates to electric contactors and particularly to the construction of the contacting parts thereof.

v It is well recognized practice, in the construc- 5 tion of contactors of the type having a pair of engageable and disengageable contacts, to render at least one of the contacts resiliently yieldable when the contacts engage each other, to avoid arcing, to insure positive electrical contact, to provide relative wiping of one contact on the other, etc.

This has heretofore been accomplished in some cases by means of a spring which holds one of the p contacts against a stop by initial tension in the '15 spring. When the contacts engage, the springpressed contact is moved from the stopand the spring is still further tensioned. The spring thus provides the necessary pressure at the point of engagement of the contacts and also permits the spring-pressed contact to have a yielding movement.

It is desirable that in such contacts the parts be so arranged that the spring can be originally assembled therewith or later disassembled therefrom, for renewal or replacement, with facility and without the use of tools and without the necessity of deforming parts of the spring.

Among the objects of the present invention are To provide an improved construction of yieldable contact for electric contactors; To provide a yieldable contact having an improved spring construction for rendering it yieldable and an improved mounting means for the spring;

To provide an improved abutment and spring guide for the spring of a contact of the type referred to;

To provide an improved spring construction for contacts of the type referred to;

To provide an improved method for making a spring abutment for contacts of the type referred to.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawing in which;

Fig. 1 is a side elevational View and Fig. 2 is a front elevational View of a part of an electric switch having contacts embodying my invention and illustrating the contacts in normal or open position;

Fig. 3 is a simplified view similar to a part of Fig. 1 but illustrating the contacts in closed position;

Fig. 4 is a view showing a part of contact construction of Figs. 1, 2, and 3, but drawn to a larger scale;

Fig. 5 is a fragmentary view taken from the plane 5-5 of Fig. 4; l V

Fig. 6 is a fragmentary view taken in the directionof the arrow 6, of Fig. 4;

Fig. 7 is a View illustrating a part of the method of making an abutment, best illustrated in Fig. 4; V

Fig. 8 is a view illustrating another step of the it) process of making the said abutment.

The improved contact construction embodying my. invention may be used on many types of contactors and I have therefore illustrated it in connection with what may be called an elemental 1 5 contactor, comprising an arm I made from insulating material pivotally supported upon a stud 2 projected through a bore in the arm. The stud 2 has a large diameter portion 3 and a threaded portion 4 projected through a bore in a panel 5 m of insulating material; the stud being thus mounted upon the panel by clamping the panel between the portion 3 and a nut 6 on the threaded portion 4.

A contact I on the arm I and movable therer with, to be more fully described, is disposed opposite a stationary contact 8 mounted on the panel 5 by a threaded stud 9 connected to the contact and projected'through a bore in the panel, the contact being secured by a nut l0.

One wire of a circuit to be controlled by the contacts I and 8 may be connected to the stud 9 and the other wire to a post II on the arm I making electrical connection with a metal plate l2 on the arm and thence through a flexible con- 5% ductor l3 to the contact 1.

The plate IZ is secured to the arm I by bolts l4 and I5 as well as by the post II and the head of the bolt [4 serves to secure one terminal of the conductor l3 to the plate.

The plate [2 projects from the arm at one end (the upper end, as viewed in Figs. 1 to 4) as shown at 16.

The end portion 1 6 of the plate is perforated as at I! and a post I8 comprising a body portion l9 E is is rigidly mounted on the plate I2 by having a neck portion 20, of reduced cross-sectional dimensions, projected through the perforation, l1 and riveted over as at 2| on the opposite side of the plate, see Fig. 4.

The post [8 is made from fiat metal, that is to say, is rectangular in cross-section as shown in Figs. 2 and 5, and as shown in end elevation in Fig. 6. Besides the body portion IS, the post -l8 comprises, at the end spaced from the plate 555 tit .rounding the body portion l9 [2, a head 22, provided by notches 23-23 in the opposite edges of the post, and by notches 24-24, which are deeper than the notches 23-23 and disposed between the latter notches and the body portion l9; a stepped neck 25 is thus provided on the post, inwardly of the head 22. The head 22 and the body portion l9 are preferably of the same width and thickness.

The contact proper, I, constitutes the end portion of a strip of metal comprising an intermediate portion 26 overlying the end portion of the plate l2 and provided with a rocker arm 21 bent at an angle to the body portion 26 toward the plate l2 and having a finger 28 of reduced crosssectional area formed on the end of the finger, thereby providing shoulders 29-29 on the finger.

The finger 28 projects through a perforation 30 in the plate l2, the shoulders 29-29 resting upon the face of the plate I2 at the sides of, the perforation 36. The body portion 26 normally rests upon the extreme end 3| of the plate ll2. The body portion 26 has therein a perforation 32 telescoped over the post I8 and normally surthereof, as best shown in Figs. 4 and 5.

A spring 33 is telescoped over the post I8 and abuts at one end upon the body portion 26 of the contact 1, and at its outer end is lodged under the head 22 of the post and therefore normally holds the contact 1 toward the plate l2 and into engagement therewith at the extreme end 3| and at the shoulders 29-29.

In operation, when the contactor arm I is rocked from the position of Fig. 1 to that of Fig. 3, and the contacts are thereby engaged, continued movement of the arm after engagement rocks the contact I about the shoulders 29-29, compressing the spring 33 and removing the end 3| of the plate I2 from the contact 1, thus engaging the contacts I and 8 with a yielding springpressed wiping movement. Return movement of the arm I will cause the end 3| of the plate l2 to pick up the contact I and disengage it from the contact 8. Any desired amount of initial tension in the spring 33 may be provided.

'vention that the spring 33 andthe post l8, particularly the head portion 22 thereof, are so formed relatively to each other that the spring may be assembled therewith without tools and without deforming the spring 33after it is initially formed, and by very simple manipulating movements of the spring, and the spring, after it is once assembled with the post, locks therewith to prevent unintended disassembly therefrom, although permitting removal of the spring for replacement or renewal purposes with the utmost facility, and this will now be described.

The inner end of the spring 33 engaging the body portion 26 of the contact I, may for convenience, be circular as shown in Figs. 5 and 6 at 34. The outer end of the spring, however, is bent into a transverse loop having the general form of a, cross preferably symmetrical around the axis of the inner end of the spring, and as shown in Fig. 6, the cross comprising, in the preferred construction, two diametrically. opposite arms or loops 35-35 and two diametrically opposite arms or loops 36-36, the latter disposed on a diameter preferably at right angles to that of the loops 35-35. The inside diameter of the loops 35-35 is preferably the same as the inside diameter of the circular body portion 34 of the spring and these two loops and the body portion 34 of the spring have an inside diameter slightly larger than the width of the post I8, whereby the body portion 34 of the spring and the loops 35-35 may be successively telescoped over the head 22.

The inside diameter of the loops 36-36 however, is smaller than the width of the head 22 and slightly larger than the width of the post l8 between the notches 23-23. The loops 35 and 36 are preferably formed in a plane at the outer end of the spring. Upon telescoping the spring over the post, it is first rotated so as to bring the loops 35-35 in position to pass over the head 22 and is telescoped far enough to bring the loops opposited the notches 24-24 and then the spring is rotated through 90 which rotates the loops 36-36 into position opposite the notches 24-24. The spring is then released and the loops 36-36 move outwardly into the notches 23-23 and are caught under the head 22.

If during the operation of the device and during successive compressions and expansions of the spring 33, it should tend to rotate, around its axis, the side portions 31-31 of the loops 36-36 will come into engagement with the faces 38-38 of the post adjacent to the notches 23-23 and rotation of the spring will be stopped, which looks the spring to the post and prevents the spring from rotating into a position at which the loops 35-35 may clear the head and release the spring.

To remove the spring for the purposes mentioned its outer end is compressed inwardly to compress the spring until the loops 36-36 are below the notches 23-23 and opposite the notches 24-24, whereupon it may be rotated back again to bring the loops 35-35 in line with the head 22 and then it may be telescoped outwardly and removed.

It will be obvious, of course, that when the spring 33 has been removed from the post I8, the contact I may be bodily removed by untelescoping it outwardly over the post I8 so that the construction provides not only for ready removal of the spring 33, but for ready removal also of the contact 7. As shown in Fig. 1 the upper end of the flexible conductor I3 is riveted to the body portion 26 of the contact at 39, so that when the contact 7 is removed, as described, to renew it, the bolt l4 may be removed to permit removal of the lower end of the conductor l3 and when this construction is employed, the conductor l3 and contact 1 are both renewed or replaced as a unit.

To form the post l8, it may be stamped bythe usual process from relatively thick sheet metal by the usual kind of dies. In some cases, however, it may be preferred to avoid the expense of making such dies and the following method may be employed. A piece of metal is first turned in a lathe to the form shown in Fig. 7, the part thus made comprising a body 40, shank 4| of reduced diameter at one end, a small diameter neck 42' in Fig. 8, leaving a central portion 48 which will have a thickness determined by the distance between the cutting planes 46 and 41. The edges 49-49thereof will have the profile of the part of Fig. 7, and this profile may be such as to give to these edges the shape shown in Fig. 4 for the post 18.

Any suitable means, not shown, may be provided to rock the arm I, and inasmuch as rock ing switch arms, such as the arm I, are well known, it is deemed unnecessary to describe such means herein.

My invention is not limited in all respects to the exact details of construction illustrated and described. Changes and modifications may be made within the spirit of my invention without sacrificing its advantages and within the scope of the appended claims.

I claim:

1. In an electric contact construction, a support, a contact element movably mounted on the support, a post on the support extending in overlapping relation to and beyond the contact element and having projections extending oppositely laterally therefrom and spaced from the contact element, a coiled compression spring surrounding the post and abutting at its inner end portion upon the contact element and at its outer end portion disposed to be engaged under the projections, the said outer end portion of the spring being provided with a transverse loop of greater dimension on one diameter than on another and when rotated to one position and compressed, being telescopable inwardly over the post and beyond the projections and when then rotated to another position and released being engageable under the projections to maintain compression in the spring.

2. In an electric contact construction,asupport, a contact element movably mounted on the support, a post on the support extending in overlapping relation to and beyond the contact ele ment and having projections extending oppositely laterally therefrom and spaced from the contact element and having spring engageable portions associated with the projections, a coiled compression spring surrounding the post and abutting at its inner end portion upon the contact element and at its outer end portion disposed to be engaged under the projections, the said outer end portion of the spring being provided with a transverse loop of greater dimension on one diameter than on another and when rotated to one position and compressed to a predetermined degree, the loop being telescopable inwardly over the post and beyond the projections and beyond the spring engageable portions and when then rotated to another position and released being engaged under the projections to maintain compression in the spring and being engaged with the spring engageable portions, and the engagement of the loop with the spring, engageable portions preventing rotation of the spring to its said one rotated position except after compression thereof to said predetermined degree.

3. In an electric contact construction, a support, a contact element movably mounted on the support, a post on the support extending in overlapping relation to and beyond the contact element and having opposite laterally extending outer projections and having opposite laterally extending inner projections shorter than the outer projections, the projections being spaced from the contact element, a coiled compression spring surrounding. the post and abutting at its inner end portion on the contact element and at its outer end portion disposed to be engaged under the outer projections, the said outer end portion of the spring being formed with a transverse cross-form loop one arm of the cross being longer than the other, whereby when the spring is rotated on its axis to one position and compressed the loop will telescope over both the outer and inner projections and after being then rotated to another position and released the long arm of the loop will engage under the-outer projections and maintain compression in the spring and the short arm of the loop will telescope with and interlock with the short projections to prevent rotation of the spring.

4. In an electric contact construction, a support, a contact element movably mounted on the support, a post on the support extending in overlapping relation to and beyond the contact element and having projection means extending laterally therefrom and spaced from the contact element and having spring engageable portions associated with the projection means, a coiled compression spring surrounding the post and abutting at its inner end portion upon the contact element and at its outer end portion disposed to be engaged under the projection means, the said outer end portion of the spring being provided with a transverse loop of greater dimension in one transverse direction than in another and, when rotated to one position and compressed to a predetermined degree, the loop being telescop-

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