US3116101A

US3116101A - Test clip

Info

Publication number: US3116101A
Application number: US20492A
Authority: US
Inventors: John M Kikta
Original assignee: Grayhill Inc
Current assignee: Grayhill Inc
Priority date: 1960-04-06
Filing date: 1960-04-06
Publication date: 1963-12-31
Anticipated expiration: 1980-12-31

Description

Dec. 31, 1963 J. M. KlKTA 3,116,101

1 TEST CLIP Filed April 6, 1960 IIIIMIIIIIH ml m I H'HH'Hn.

IN VEN TOR.

iii!!! 11 BY Iljgllllll 16 W W United States Patent .1 3,116,101 TEST CLIP John M. Kiirta, Downers Grove, 11]., assignor to Grayhili, Inc., La Grange, 111., a corporation of Illinois Filed Apr. 6, 1960, Ser. No. 20,492 2 Claims. (Cl. 339-258) This invention relates to holding devices for use as electrical connectors, and more particularly to improved miniature electrical test clips.

The manufacture and maintenance of electrical products involves a great deal of testing which requires that such products be electrically connected in a circuit containing an electric meter. Temporary test connections of resistors, capacitors, transistors and other components having pigtail type leads are commonly made by means of electrical test clips. Test clips of the type designed for panel mounting on test equipment and also those designed for use in bread-board work must be durable and yet allow for rapid connections without requiring much attention on the part of the user. In addition, they should be capable of handling a range of wire sizes or other objects without adjustment, and some means of varying the clamping force should be provided. Although a variety of test clips are available, they are not entirely satisfactory from the standpoint of size, cost and flexibility of use.

Accordingly, it is an object of the present invention to provide a test clip which is strong and durable and yet easily made in miniature form for a variety of mountings.

Anotherobject of the invention is to provide a simple, strong holding device to which rapid electrical and/or mechanical connections of objects of various sizes and shapes may be securely made without manual opening and closing of jaws.

A further object is to provide a simple, strong test clip which is easily adjustable in tension and which is readily adaptable to receive a plurality of wires in a variety of engagements.

A feature of the invention is the provision of a holding device including a rigid post and a flexible contact portion assembled to the post by the stem of post provided for mounting the post on a chassis.

Another feature of the invention is the provision of a miniature test clip including a rigid member with a post portion and a threaded mounting stem, and one or more resilient contact members having openings for receiving the stem and shaped to be forced toward contact surfaces on the post portion of the rigid member when drawn thereto by a nut on the stem.

In the accompanying drawing:

FIG. 1 is a greatly enlarged perspective view of a test clip constructed in accordance with the invention and mounted on a printed circuit board;

FIG. 2 is a greatly enlarged side elevational view of the test clip of FIG. 1;

FIG. 3 is a front elevational view of the same;

FIG. 4 is a top plan view of the same;

FIG. 5 is an elevational side view of a test clip having two spring members showing a wire inserted therein;

FIG. 6 is .a side elevational view of a modified form of the test clip in accordance with the invention; and

FIG. 7 is a side elevational view of still another form of the invention.

The invention provides a miniature electrical test clip 3,116,1dl Patented Dec. 31, 1963 ice for obtaining rapid, temporary test connections to a wire lead. The test clip comprises two basic parts; a strong, rigid elongated member having a head or post portion and a stem mounting portion, and a bent resilient member received against and supported by the former. The resilient member has a curved, apertured base portion which is received on the stem portion, and a flexible, wire engaging contact portion which -is urged towards a contact surface of the rigid member by the flattening of the base portion between a shoulder on the rigid memher and either a nut received on the stem portion or the surface on which the rigid member is mounted. A stop may be formed either on the rigid member or on the resilient member to restrain movement of the wire lead as it is positioned on the clip. Several resilient members may be provided on one rigid member when a plurality of wires are to be connected thereto. The clip may be used to support various objects, and the resilient member may be variously shaped to provide different degrees of engagement with the wires or other objects to be held.

Referring now in more detail to the drawing, FIG. 1 illustrates a miniature test clip 10 mounted on a printed circuit board 11, with the lead wire 12 of a small pigtail component being inserted therein by hand. The thumb and forefinger of an adult illustrate the diminutive size of the test clip, which in the particular embodiments illustrated has an overall length of about W of an inch.

The test clip of FIG. 1 is shown greatly enlarged in the side, front and top view of FIGS. 2, 3 and 4 respectively. The principal supporting element of the test clip is a rigid elongated member 13 with an enlarged upper post or head portion 14 and a reduced lower stem portion 16. The rigid member 13 may be made of nonferrous materials having good conductivity, such as nickel plated brass or other suitable materials. Head 14 is square shaped and therefore provides four substantially fiat sides any or all of which may serve as electrical contact surfaces. However, other head shapes, such as triangular or hexagonal, may be used as desired. The reduced portion or stem 16 carries an external thread adapted to receive

hex nuts

17 and 18 for mounting the bolt on a panel member such as circuit board 11 or to screwably mount the bolt in a threaded hole provided in a meter housing or other mounting devices. The junction of the threaded stem and the bolt head forms ashoulder 19 whose spacing from the upper surface of nut 18 depends upon the extent to which the bolt is screwed'into board 11 and the corresponding setting of '

hex nuts

17 and 13.

A resilient or spring-like member 21 provides the opposing jaw of the test clip. This member may be readily stamped from a thin, fiat piece of suitable spring sheet metal such as heat treated beryllium copper shaped into a generally L-shaped configuration comprising two principal portions, a bowed base portion 22 and an upwardly extending contact portion 23. An aperture or hole 24 is formed in the center of base portion 22 which receives stem 16 therethrough in mounting spring member 21 on bolt 13. When thus mounted it is to be noted that base portion 22 is bowed away from, or convexly disposed with respect to shoulder 19 of head 14. Since spring 21 is entirely resilient throughout, it will be seen that screwing the bolt down into board 11 or drawing 3 nut 18 up towards shoulder 19 will flex or flatten the bowed base portion. This flattening of the base portion in turn urges contact portion 23 more firmly against the contact face of head 14. Thus, it is a simple matter to vary the Spring tension of the test clip.

Normally, both the bolt and the spring member are utilized as electrically conducting members in the test clip since they will always be in firm mechanical contact with one another. But for certain applications it may be preferred to construct the bolt of insulating material, such as hard plastic, and rely solely on the spring member to provide the conducting path. Since the bolt is made rigid and need not be reduced in size to the extent of the spring member, such materials are entirely compatible with the test clip of the invention.

The upper or contact portion 23 of the resilient member 21 can be shaped as desired to provide the particular engagement best suited for the size and type of com ponents being inserted. Thus, the contact portion 23 shown in the embodiment of FIGS. 1-5 has a flared-out portion 25 at the upper end thereof which allows a wedging action to facilitate insertion of a wire between spring 21 and the adjacent contact surface of head 14. Immediately below this flared-out portion there is a generally straight or flat wire engaging portion which terminates in an inwardly depressed stop portion 26 shaped to form a projection to limit downward movement of the wire (FIG. The depth of this depression depends upon the range of wire sizes to be tested and is, of course, limited by the smallest wire size for which the clip is to be used. The remaining portion of the spring member, between depression 26 and base portion 22, is angularly disposed with respect to the adjacent contact face of head 14 and serves to transmit the stresses resulting from the flexure of the base portion 22 to the points of actual engagement of the spring member with an inserted wire.

A modified form of the invention is illustrated in FIG. 6 wherein elements identical with those previously described are given like reference numerals, and their de scription is not repeated. A modified spring member 27 is provided which differs from spring member 21 in that depressed portion 26 is provided with a further projecting dimple 28 which extends into a mating recess 29 formed in the contact surface of head 14- opposite spring 27. Dimple 28 protrudes fully into recess 29 when there is no wire inserted in the test clip, and prevents a wire inserted between the spring and the head from being forced all the way to the bottom. This extended stop portion is advantageous when it is desired to accommodate a larger range of wire sizes than is possible without the recess as well as in situations where a heavy insertion force is to be expected from the testing personnel.

Another variation found in this embodiment is the shaping of the contact portion of spring member 27.

While the upper end of the member is again provided with the gradually flared-out portion 25, a portion 31 immediately therebelow is bent sharply away from the contact face of head 14. A wire engaging portion 32 extends generally parallel to the contact face. This configuration of the upper portion of spring 27 provides a gentle taper so that only a small force is required to insert a wire, with the abrupt angle provided by portion 31 requiring a substantially greater force to pull the wire out of the clip. It will be apparent that further modifications in the shape of the contact portion 25 are readily obtainable should a special form be desired to hold an object other than a wire. For example, the connector of the invention can be used to hold the body or case of a small transistor for electrical connection when the case is an electrical element of the same.

FIG. 6 also illustrates the adaptability of bolt 13 to various mounting means. A standard banana plug 33 provided with an internally threaded center hole receives threaded portion 16 therein, and the upper surface of 4 the plug provides the adjustable engagement with base portion 22.

Another modification of the invention is shown in FIG. 7. In this embodiment head 14 of bolt 13 is provided with a transversely disposed hole 34 adapted to receive a pin 35 which extends a given distance from 0ppositely disposed contact faces of head 14. Two identical spring members 37 are received on the bolt with their base portions 22 overlapping. Their upper contact portions contain apertures 38 adapted to receive the projecting pins 36 therethrough. Pins 36 thus do not interfere with the engagement of spring members 37 against their respective contact faces, but do provide a positive stop for a wire inserted between the spring members and the head.

It is to be understood that

spring members

21 and 27 likewise may be mounted in pairs in the manner of spring members 37. In FIG. 5 a test clip is shown having a pair of spring members 21. Since head 14 is square shaped a total of four spring members may be mounted against the four contact faces when it is desired to connect a plurality of Wires to one test clip.

FIG. 7 also illustrates another method of mounting the test clip. Here the threaded stem of the clip is screwed into a panel 39, the panel itself providing the surface to bear against base portion 22 while

hex nuts

17 and 18 are utilized to hold electrical connecting lug 41.

The above-described test clip thus provides a versatile electrical connector easily adapted for a variety of applications. Due to the provision of a rigid bolt 13 it can be made in extremely small sizes since the strength of the thinner spring members is not relied upon to support the assembly. The spring members are easily mounted on the bolt and the mounting provides a convenient method of adjusting the tension of the spring member against the contact face of the bolt head. Moreover, the form of the bolt may be standardized and then various forms of spring members may be supplied as accessory items to convert the test clip from one appli cation to another.

The clip is easily adapted for holding objects other than wire leads, and may be used simply as a fixture, either to hold a part for electrical test or merely as a mechanical holding device. Due to its comparatively large mass, the rigid member may also serve as a heat sink to absorb heat away from relatively delicate components such as transistors during a soldering operation.

I claim:

1. A miniature electrical test clip for making a connection to a wire including in combination, a rigid conductive member having an elongated post portion of square cross section with substantially flat sides and a reduced externally threaded lower stem portion, with the junction of said post portion and said stem portion forming a shoulder therebetween, internally threaded mounting means on said stem portion, and a generally L-shaped conductive sheet metal spring member having a bowed base portion and a contact portion, said base portion having a hole therethrough adapted to receive said threaded stem portion for mounting said spring member thereon between said shoulder and said mounting means, with said bowed base portion convexly disposed against said shoulder and said contact portion extending upwardly along said post portion, said bowed base portion of said resilient member being clamped and flexed between said shoulder and said mounting means to urge said contact portion of said spring member towards one flat side of said post portion with a force inversely proportional to the distance between said shoulder and said mounting means, said contact portion including a depressed portion forming a projection lying against said fiat side of said post portion and further including an upper flaredout portion at the upper end thereof normally engaging said post portion with the part of said contact portion between said depressed portion and said flared-out portion being substantially fiat, so that a wire inserted downwardly between said side of said post portion and said flared-out portion of said spring member flexes said contact portion away from said post portion and the wire is then held in resilient engagement between said fiat side of said post portion and said substantially flat part of said contact portion, with said projection formed by said depressed portion of said contact portion underlying the wire and limiting the downward movement thereof.

2. A test clip in accordance with claim 1 including a further L-shaped conductive spring member having a bowed base portion and a contact portion, with said base portion of said further spring member having a hole therein for receiving said threaded stem portion of said rigid conductive member for mounting said further spring member between said shoulder and said mounting means, and said contact portion of said further spring member engaging a different side of said post portion and having 6 an upper flared-out portion and a depressed portion with a substantially flat part therebetween.

References Qited in the file of this patent UNlTED STATES PATENTS 2,062,690 Weynand Dec. 1, 1936 2,297,036 Tallman Sept. 29, 1942 2,380,114 Kurillo July 10, 1945 2,458,511 Harlow Jan. 11, 1949 2,726,376 Heath Dec. 6, 1955 2,761,115 Visconti Aug. 28, 1956 2,851,669 Koch Sept. 9, 1958 2,853,520 Chance Oct. 28, 1958 2,997,680 Arthur Aug. 22, 1961 FOREIGN PATENTS 610,463 Great Britain Oct. 15, 1948

Claims

1. A MINIATURE ELECTRICAL TEST CLIP FOR MAKING A CONNECTION TO A WIRE INCLUDING IN COMBINATION, A RIGID CONDUCTIVE MEMBER HAVING AN ELONGATED POST PORTION OF SQUARE CROSS SECTION WITH SUBSTANTIALLY FLAT SIDES AND A REDUCED EXTERNALLY THREADED LOWER STEM PORTION, WITH THE JUNCTION OF SAID POST PORTION AND SAID STEM PORTION FORMING A SHOULDER THEREBETWEEN, INTERNALLY THREADED MOUNTING MEANS ON SAID STEM PORTION, AND A GENERALLY L-SHAPED CONDUCTIVE SHEET METAL SPRING MEMBER HAVING A BOWED BASE PORTION AND A CONTACT PORTION, SAID BASE PORTION HAVING A HOLE THERETHROUGH ADAPTED TO RECEIVE SAID THREADED STEM PORTION FOR MOUNTING SAID SPRING MEMBER THEREON BETWEEN SAID SHOULDER AND SAID MOUNTING MEANS, WITH SAID BOWED BASE PORTION CONVEXLY DISPOSED AGAINST SAID SHOULDER AND SAID CONTACT PORTION EXTENDING UPWARDLY ALONG SAID POST PORTION, SAID BOWED BASE PORTION OF SAID RESILIENT MEMBER BEING CLAMPED AND FLEXED BETWEEN SAID SHOULDER AND SAID MOUNTING MEANS TO URGE SAID CONTACT PORTION OF SAID SPRING MEMBER TOWARDS ONE FLAT SIDE OF SAID POST PORTION WITH A FORCE INVERSELY PROPORTIONAL TO THE DISTANCE BETWEEN SAID SHOULDER AND SAID MOUNTING MEANS, SAID CONTACT PORTION INCLUDING A DEPRESSED PORTION FORMING A PROJECTION LYING AGAINST SAID FLAT SIDE OF SAID POST PORTION AND FURTHER INCLUDING AN UPPER FLAREDOUT PORTION AT THE UPPER END THEREOF NORMALLY ENGAGING SAID POST PORTION WITH THE PART OF SAID CONTACT PORTION BETWEEN SAID DEPRESSED PORTION AND SAID FLARED-OUT PORTION BEING SUBSTANTIALLY FLAT, SO THAT A WIRE INSERTED DOWNWARDLY BETWEEN SAID SIDE OF SAID POST PORTION AND SAID FLARED-OUT PORTION OF SAID SPRING MEMBER FLEXES SAID CONTACT PORTION AWAY FROM SAID POST PORTION AND THE WIRE IS THEN HELD IN RESILIENT ENGAGEMENT BETWEEN SAID FLAT SIDE OF SAID POST PORTION AND SAID SUBSTANTIALLY FLAT PART OF SAID CONTACT PORTION, WITH SAID PROJECTION FORMED BY SAID DEPRESSED PORTION OF SAID CONTACT PORTION UNDERLYING THE WIRE AND LIMITING THE DOWNWARD MOVEMENT THEREOF.