US3268852A

US3268852A - Electrical clip contact device

Info

Publication number: US3268852A
Application number: US438901A
Authority: US
Inventors: Wennersten Bo
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-03-16
Filing date: 1965-03-11
Publication date: 1966-08-23
Anticipated expiration: 1983-08-23
Also published as: GB1097311A; NO116631B; CH431669A; BE661134A; DK116522B; DE1227980B; NL6503245A

Description

Aug. 23, 1966 B. WENNERSTEN 3,268,852

ELECTRICAL CLIP CONTACT DEVICE Filed March 11, 1965 United States Patent 3,268,852 ELECTRICAL CLIP CONTACT DEVICE Bo Wennersten, Medsolbacken 15, Vallingby, Sweden Filed Mar. 11, 1965, Ser. No. 438,901 Claims priority, application Sweden, Mar. 16, 1964, 3,236/64 6 Claims. (Cl. 339258) The present invention relates to an electrical contact device of the clip type in which the two parallel legs of the clip are adapted to clamp between them a contact blade. The invention, more particularly, has for its object to provide such contact devices with an arrangement adapted simultaneously to fulfil two functions, namely to increase the contact pressure by which the two legs of the clip clamp the contact blade between them, and to positively prevent the blade from inadvertently leaving its closed position. The principal object of the invention may be stated as being the provision of an arrangement not only combining in itself the dual functioning just described but also being structurally simple whereby it is cheap to manufacture and convenient in handling as well as safe in operation.

Several devices are previously known which fulfil the first-mentioned function, i.e. to increase the contact pressure between the clip and blade. However, all these priorart constructions have in common the drawback of being relatively complex and bulky, primarily for the reason that they were always so designed that the contact-pressure producing or augmenting force gives rise to a reaction force which will have to be taken up by some structural element or other included for this particular purpose and being in the form of a frame or support which was rigidly connected with the body of the electrical apparatus concerned with which the clip contact is associated. A specific object of the invention is the provision of an arrangement capable of producing an increased contact pressure against said contact blade with out the necessity of transmitting the corresponding reaction forces to any part outside the contact clip, said reaction forces being instead absorbed or neutralised in this clip proper.

A third object of the invention is to provide means completely or partly integral with the arrangement referred to in the last-preceding paragraph and adapted purely mechanically, or positively, to prevent the contact blade from inadvertently leaving its closed position. This could occur for any of two principal reasons. The first one involves that the position of the blade is disturbed by any direct mechanical action thereon, such as in the form of vibrations or impacts. One usual case of this type occurs when the contact blade forms part of, for example, a bridge fuse mounted on a movable contact bridge of a fuse switch. The second main cause of an inadvertent disengagement of the contact blade from its operative position depends on the excessive electromagnetical forces produced as the currentfor instance when short-circuiting takes placeattains very high values and, due to the configuration of the current path concerned, tending to throw out the fuse or corresponding member from its contact clips.

The mainly characterizing feature of the arrangement of the invention resides in that it comprises an element which is movable between a first position in which the opening between the two extreme ends of the clip legs is unobstructed, and a second position in which said element is adapted both to obstruct said clip opening thereby preventing the contact blade from moving out through the same, and to augment the contact pressure between the blade and each of the clip legs.

One embodiment of the invention will be described hereinafter with reference to the accompanying diagrammatic drawing, in which:

"Ice

FIG. 1 is an end view of a contact clip provided with an arrangement according to the invention, said movable element being shown in a position in which the contact blade is latched against getting thrown out of engagement, but in which the second main function, i.e. the augmentation of contact pressure, is not attained;

FIG. la illustrates the device of FIG. 1 in a View at right angles thereto;

FIGS. 2 and 2a correspond to FIGS. 1 and la, respectively, with the exception that in the present case said movable element is in its contact-pressure augmenting position;

FIG. 3 is a view of the device corresponding to those of FIGS. la and 2a, respectively, but with the movable element in its completely open position, i.e. in a position in which it will afford neither any latching action nor any increase of the contact pressure.

Numeral 1 designates a clip contact member having two legs or

jaws

2 and 3. These legs clamp between them a blade contact member or blade 4 which is presumed to form a part of an electrical apparatus, such as a bridge fuse, for example. The free ends of the

clip legs

2 and 3 are bent out substantially perpendicularly to the flat sides of the contact blade 4. These laterally extending portions of the legs have been denoted by 5 and 6, respectively. Leg portion 5 carries a pin 7 having a cylindrical head 8 provided with a screw driver slot and journalled in a hole made in leg portion 5. Leg portion 6 is provided with a large stud 9 being also provided with a head, as shown. Pivoted on the pin 7 is a somewhat hook-like element 10 the notch 11 of which is intended to cooperate with stud 9. The portion of pin 7 disposed between leg portion 5 and pin head 8-is provided with an eccentric 12 intended to cooperate with an opening made in the hook-like element 10.

The arrangement thus described operates as follows. After the contact blade 4 has been moved into its closed position, during which operation the hook 10 should, of course, be in its angular position shown in FIG. 3, the hook is moved into its position shown in FIG. 1. Then, by means of a screw driver, the pin 7 is rotated whereby, by cooperation of the eccentric 12 with the associated opening in the hook 10, the latter will be positively forced in the left-hand direction. After engagement having been reached between the inner edge surface of the extreme end portion 13 of the hook and the stud 9, a continued rotation of pin 7, obviously, will cause the contact blade 4 to be increasingly forcefully clamped between the

legs

2 and 3.

According to more specific features of the invention, the device is suitably provided with elements in the form of stop lugs which will facilitate its handling. Numeral 14 designates such a stop lug. The latter should be placed in a position such that, when the pin head 8 has been moved into engagement with the same, thereby restraining continued turning of the pin, the eccentric 12 should occupy the position in which maximum contact pressure is afforded between the

clip legs

2, 3 and the contact blade 4. Disposed at the diametrically opposite side of the pin head is a similar stop lug 15. The purpose of the latter is to ensure that, after the pin having been rotated in a contact-pressure relieving sense until the pin head 8 has engaged said stop lug, a continued turning of the pin in the same sense, i.e. counter-clockwise in the exemplary embodiment shown, shall result in carrying the hook 10 into the open position thereof as illustrated in FIG. 3. This in its turn is defined by a third stop lug 16 which is bent up from the extreme end of the bent-out portion 5 of the clip contact leg 2 (FIG. 3). It will be seen from the above that all three stop lugs can be conveniently produced by punching and bending operations which contributes to the very low cost of manufacture of the device. Spring washers or the equivalent are suitably associated with the pin 7 in order to increase the friction during pivoting of the book 10. This arrangement in combination with the presence of stop lug 15 is of particular value where the hook 10 is mounted in a manner to be gravitationally returned into its obstructing position.

The embodiments of the invention described and illustrated in the drawing have been chosen merely by way of example, and several modifications are possible. It may he stated, for example, that the pin 7 may be replaced by a screw-threaded pin having a conically shaped neck. A third possibility would be to dispose the pin or screw concerned in such a way that its longitudinal axis will be parallel with that of the hook 10. Further, the pin head 8 may be formed as an eccentric adapted, as the contact pressure increases, to cooperate with the stop lug or with any suitable other part of the device.

I claim:

1. An electrical clip-type contact device, comprising: a contact member having two parallel legs which are adapted to clamp a contact blade between them; a hooklike element pivotally attached to one of said legs, a studlike member carried by the other leg, said hook-like element being movable between a first position in which the opening between the two extreme ends of said legs is unobstructed, and a second position in which said hook-like element is cooperating with said stud-like member in order both to obstruct said opening, thereby preventing said contact blade from moving out through the same, and to augment the contact pressure between the blade and each of the clip legs, a rotatable pin serving as a pivot pin for said hook-like element; and an eccentric carried by said rotatable pin, said eccentric being adapted to cooperate with a pressure surface of said hook-like element for displacing said hook-like element into its obstructing position.

2. A contact device according to claim 1 wherein a first stop lug adapted in cooperation with said pin to prevent rotation of the latter beyond the angular position in which the contact pressure produced by said eccentric has its maximum value.

3. A contact device according to claim 2, wherein a second stop lug adapted in cooperation with said pin when rotated in a contact-pressure diminishing sense to carry with it said hook-like element so as to swing the latter away from its obstructing position.

4. A contact device according to claim 3 wherein said stop lugs being constituted by tongues formed integral with said hook-like element by punching and bending up from the plane thereof.

5. A contact device according to claim 4, wherein a third stop lug adapted to limit the angular movement of said hook-like element from its obstructing position to a position in which its longitudinal axis is essentially parallel to that of the contact blade.

6. An electrical clip-type contact device, comprising: a generally U-shaped contact member adapted to clamp a contact blade between the legs of said contact member; a fixed stud-like member on a first of said legs of said contact member; a closure member pivotally mounted on the other of said legs of said contact member and adapted to pivot between a closed position across the opening of said contact member and an open position away from said opening; and pressure means operatively coupled to said closure member and adapted to pivot said closure member between its open and closed positions and apply pressure to said stud-like member, thereby increasing the clamping pressure of said contact member on said contact element, when said closure member is in said closed position.

References Cited by the Examiner UNITED STATES PATENTS 1,917,862 7/1933 Wadsworth 339253 EDWARD C. ALLEN, Primary Examiner.

PATRICK A. CLIFFORD, Examiner.

I. H. MCGLYNN, Assistant Examiner.

Claims

1. AN ELECTRICAL CLIP-TYPE CONTACT DEVICE, COMPRISING: A CONTACT MEMBER HAVING TWO PARALLEL LEGS WHICH ARE ADAPTED TO CLAMP A CONTACT BLADE BETWEEN THEM; A HOOKLIKE ELEMENT PIVOTALLY ATTACHED TO ONE OF SAID LEGS, A STUDLIKE MEMBER CARRIED BY THE OTHER LEG, SAID HOOK-LIKE ELEMENT BEING MOVABLE BETWEEN A FIRST POSITION IN WHICH THE OPENING BETWEEN THE TWO EXTREME ENDS OF SAID LEGS IN UNOBSTRUCTED, AND A SECOND POSITION IN WHICH SAID HOOK-LIKE ELEMENT IS COOPERATING WITH SAID STUD-LIKE MEMBER IN ORDER BOTH TO OBSTRUCT SAID OPENING, THEREBY PREVENTING SAID CONTACT BLACE FROM MOVING OUT THROUGH THE SAME, AND TO AUGMENT THE CONTACT PRESSURE BETWEEN THE BLADE AND EACH OF THE CLIP LEGS, A ROTATABLE PIN SERVING AS A PIVOT PIN FOR SAID HOOK-LIKE ELEMENT; AND AN ECCENTRIC CARRIED BY SAID ROTATABLE PIN, SAID ECCENTRIC BEING ADAPTED TO COOPERATE WITH A PRESSURE SURFACE OF SAID HOOK-LIKE ELEMENT FOR DISPLACING SAID HOOK-LIKE ELEMENT INTO ITS OBSTRUCTING POSITION.