US3648222A

US3648222A - Electrical connector having laminated contact element

Info

Publication number: US3648222A
Application number: US19822A
Authority: US
Inventors: Richard R Cowmeadow
Original assignee: Bunker Ramo Corp
Current assignee: Amphenol Corp; Bunker Ramo Corp
Priority date: 1970-03-16
Filing date: 1970-03-16
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07
Also published as: DE2111777B2; CA929621A; FR2084621A5; IL36260A0; IL36260A; CH521029A; DE2111777A1; DE2111777C3; GB1341628A; SE378485B; NL7102559A; ZA711161B

Abstract

Electrical connector including a plurality of thin metal plates forming a laminated contact element and formed with integral resilient tines projecting in equiangularly spaced relation from peripheral portions of aligned holes in the plates to engage contact elements which are preferably filter pin units, the tines and plates functioning to provide a repeatably low-impedance electrical contact and path from the outer electrodes of the filter pin units to ground.

Description

United States Patent C-owmeadow [54] ELECTRICAL CONNECTORHAVING LAMINATED CONTACT ELEMENT [72] Inventor: Richard R. Cowmeadow, Bramalea, On-

tario, Canada [73] Assignee: The Bunker-Ramo Corporation, Oak

Brook, [11.

[22] Filed: Mar. 16, 1970 [21] Appl. No.: 19,822

[52] 11.8. (I1 ..339/l4 R, 24/204, 24/216, 339/262 R, 333/79 [51] Int. Cl ..H0lr 11/22, HOlr 3/06 [58] Field of Search ..339/l4, 17, 22 B, 262, 232, 339/256, 258, 259; 24/73 BP, 73 B, 216, 204

[56] References Cited UNITED STATES PATENTS 1,477,527 12/1923 Raettig ..339/262 R X 2,423,548 7/1947 Bels ..339/262 R 5] Mar. 7, 1972 3,519,975 I 7/1970 Prow ..339/l4P FOREIGN PATENTS OR APPLICATIONS 1,026,823 3/1958 Germany ..339/262 601,294 5/1948 Great Britain ....339/262 R 6,810,231 1/1971 Netherlands ..339/262 R Primary Examiner-Marvin A. Champion Assistant Examiner-Robert A. Hafer Attorney-Frederick M. Arbuckle l 5 7 ABSTRACT Electrical connector including a plurality of thin metal plates forming a laminated contact element and formed with integral resilient tines projecting in equiangularly spaced relation from peripheral portions of aligned holes in the plates to engage contact elements which are preferably filter pin units, the tines and plates functioning to provide a repeatably low-impedance electrical contact and path from the outer electrodes of the filter pin units to ground.

10 Claims, 7 Drawing Figures ELECTRICAL CONNECTOR HAVINGLAMINATED CONTACT ELEMENT This invention relates to an electrical connector and more particularly to an electrical connector which accommodates a wide range of contact sizes, has improved electrical performance, especially with regard to high frequencies, and which is highly reliable both mechanically and electrically while being economically manufacturable.

The principles of this invention have other applications but are especially advantageous in a connector of a type having a plurality of filter pin contact units therein, each of which may comprise inductance elements and capacitance elements arranged to form a passive filter to prevent transmission of undesirable high-frequency or noise signals. To provide a ground connection to outer cylindrical-electrodes of such filter pin units, a ground plate has heretofore been provided having holes through which the filter pin units extend, with a plurality of tines extending from edge portions of each hole to engage angularly spaced portions of each electrode. Such tines have of necessity been quite 'short, thick and stiff, and a high degree of accuracy has been required in the formation thereof. It has not been possible to accommodate any substantial range of variation in the diameter of the filter pin units and also the connectors have not been entirely satisfactory and reliable either from an electrical or a mechanical standpoint.

This invention was evolved with the general object of overcoming the disadvantages of prior art connectors and of providing a connector having improved performance both electrically and mechanically while being highly reliable and also economically manufacturable.

According to this invention, a laminated contactelement is provided which comprises a plurality of thin plates each having at least one and preferably a plurality of holes therein with an integral resilient tine projecting from an edge portion of each hole, the holes in the plates being aligned. Preferably, the holes in the plates are aligned by providing locating holes adapted to receive spigots of thermoplastic inserts in a manner such as to insure the proper relative location of the tines. The laminated contact element may preferably be sandwiched between a pair of support members having passages aligned with the holes and contacts extended through the passages and holes are engaged by the tines, each contact being engaged with a number of tines equal to the number of plates.

With this arrangement, the tines can be relatively thin and long with a length dimension of the same order of magnitude as the diameter of the holes. As a result, the tines are quite resilient and can firmly engage any contact having a diameter lying within a quite wide range of dimensional values. In addi' tion, the area of the interengaging surfaces can be quite large to obtain a low-resistance connection. The large area of engagement is also desirable in conducting away any heat generated by current flow or otherwise. The tines can thus be of any designed shape necessary to shield the control and to make a good low-impedance ground, while allowing variance of tine pressure (normal force) to suit the contact design.

The arrangement is particularly advantageous when used with filter pin contact units designed to filter out high-frequency noise or extraneous signals. Because of the large area of contact, a very low inductance is obtained and since highfrequency currents are concentrated at the surface of a conductor, the use of a plurality of plates reduces the effective resistance to ground.

This invention contemplates other objects, features and advantages which will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate a preferred embodiment and in which:

FIG. 1 is a side elevational view of an electrical connector incorporating a laminated contact element in accordance with this invention;

FIG. 2 is a sectional view taken substantially along line ll II of FIG. 1 and showing a cross section one of a plurality of filter pin contact units engaged by tines of the laminated contact element;

FIG. 3 is a cross-sectional view taken substantially along line III-Ill of FIG. 2;

FIG. 4 is a plan view, on an enlarged scale, illustrating a portion of the laminated contact element and the positioning of tines thereof before assembly in the connector;

FIG. 5 is a cross-sectional view taken substantially along V-V of FIG. 4;

FIG. 6 is a plan view of a portion of one plate of the laminated contact element, illustrating the form thereof before bending of the tines thereof; and

FIG. 7 is a view similar to FIG. 6, but showing a portion of another of the plates of the laminated contact element.

Reference numeral 10 generally designates an electrical connector structure incorporating a laminated contact element in accordance with the principles of this invention. The illustrated structure 10 is a receptacle portion of an electrical connector to which a plug portion may be connected to interconnect contacts within the plug and receptacle portion.

Disposed within the structure 10 are a multiplicity of filter pin contact units a portion of one of which is illustrated in FIGS. 2 and 3 and designated by a reference numeral 11. The contact unit 11 is disposed in aligned passages l2, l3 and 14 of members l5, l6 and 17.

Members

15 and 16 are preferably of a relatively rigid insulating material while member 17 is preferably of a relatively soft elastomeric material. Member 15 is disposed within a connector shell member 20 while

members

16 and 17 are disposed within a cylindrical insert member 21 telescoped within the right-hand portion of shell member 20. A rotatable coupling ring 22 is threaded on the right-hand portion of the shell 20 and is arranged to move the insert member 21 in a locking direction, to the left as viewed in FIGS. 1 and 3, to position the parts as shown. When rotated in the opposite direction, the insert member 21 may be moved to the right, and the filter pin contact units may be more readily removed, for inspection, repair and replacement. When rotated to the locked position, a detent spring 23, carried by a lock ring 24 secured to the insert 21, engages a notch of the coupling ring 22 to prevent rotation thereof.

The filter pin contact units are quite small in size and very thin and a large number thereof may be incorporated in a connector structure of relatively small size. By way of example, approximately 50 of such units may be incorporated in a connector as shown in which the outside diameter of the

members

15, 16 and 17 is approximately 1% inches.

The contact unit 1] which is like all others of the connector, includes an intermediate filter section which includes ferrule elements 26 of a ferrite material on a central conductive portion 27, operative to increase the inductance. A pair of sleeves 28 of thin metal or foil are disposed around the ferrule means 26 and within a sleeve 29 of a dielectric material. An outer sleeve or electrode 30 is disposed around the dielectric sleeve 29. The pair of sleeves 28 are connected through rings 31 and 32 of conductive rubber or the like to enlarged portions 33 and 34 connected electrically to opposite ends of the narrow central portion 27.

The purpose of the illustrated construction of the unit 11 is to provide a low-pass filter which filters out noise or extraneous electrical signals having a frequency above a certain frequency. It is essential for proper operation of the filter that the low-resistance and low-inductance ground connection be provided to the outer electrode 30. Heretofore, it has been the practice to provide a ground plate having a hole for each of the contact units and having a plurality of tines extending inwardly from angularly spaced edge portions of each hole to engage the outer electrode of the contact unit. As mentioned previously, difficulties have been experienced with such ground plates.

In accordance with this invention, a laminated grounding contact element is provided, generally designated by reference numeral 36 which comprises a plurality of thin metal plates, four

plates

37, 38, 39 and 40 being provided in the illustrated construction. Plates 37-40 have aligned holes 41-43 through which the contact unit 11 extends and are additionally formed with integral tines 45-48 extending from edge portions of the holes 4143, respectively. Preferably, as shown, the tines 45-48 all project in the same direction, it being noted that the tine 46 of plate 38 projects through the hole 41 of the plate 37, the tine 47 of the plate 39 projects through

holes

43 and 42 of the

plates

37 and 38 and the tine 48 of the plate 40 projects through holes 41-43 of the plates 37-39. Thus, the contact unit can be readily inserted from the right, as viewed in FIG. 3. To permit ready withdrawal of the contact unit, however, the tines 45-48 are preferably formed with outwardly bent end portions 45A-48a.

With the laminated construction, each of the tines can have a length dimension of the same order of magnitude as the hole diameter, each tine having a length approximately equal to the hole diameter in the illustrated construction. A variety of tine shapes are possible depending on the frequency composition of signals to be handled. Thus, the tines can be quite long as compared to the permissible length in the prior construction. Also, the tines can be quite wide the width being roughly equal to one-half of the hole radius as illustrated but with or without a slight taper from the base of each tine to the terminal end thereof.

With the construction as illustrated, the permissible deflection of the tine is quite large and a wide range of filter pin unit diameters can be accommodated, while still insuring firm engagement with the outer electrode of the unit. The contact units can be removed and replaced a number of times without damage to the tines or the effectiveness thereof. It is also possible to obtain a greater area of electrical contact and both a lower electrical resistance and a lower effective inductance. In conjunction with a filter pin contact unit, it is highly desirable that the inductance as well as the resistance be as low as possible, to effectively remove higher frequency components. It is also noted that since high-frequency currents are concentrated in the surface portions of conductors, the use of a plurality of plates reduces the electrical resistance and enhances the grounding action.

The tines 45-48 are preferably arranged in equiangularly spaced relation to provide a centering action, a 90 spacing being provided with four tines as illustrated, Preferably, at least three tines are used to obtain a centering action which would be much better than would be obtained with only two tines. With four tines, the centering action is somewhat better, and a greater total area of contact is obtained. A greater number of tines can be provided but the cost of manufacture would be increased. Generally, at least three are preferably provided, most preferably four, as illustrated.

FIGS. 6 and 7 illustrate the form of two of the plates, plates 37 and 40, prior to bending of tines. In the plate 37, a first row of holes 51 are provided with tines 52 projecting outwardly to the left at a 45 angle in the illustrated orientation of the plate 37. A second row of holes 53 is provided with tines 54 projecting downwardly and to the right at a 45 angle, the orientation thus being opposite to the tines 52. A third row of holes 55 have tines 56 oriented the same as the tines 52 and the tines of the next row of holes, not shown, are oriented the same as the tines 54, the tines of adjacent holes being thus oriented oppositely. The hole 41 and tine 45, shown in FIGS. 2-5 are not shown in the portion of the plate 37 illustrated in FIG. 6, but it will be understood that the hole 41 may be in one of the rows adjacent the periphery of the plate 37.

In the plate 40, a first row of holes 57 have tines 58 extending downwardly and to the left at a 45 angle, a second row of holes 59 have tines 60 extending upwardly and to the right at a 45 angle, a third row of holes 61 have tines 62 oriented the same as the tines 58 and a fourth row of holes 63 have tines 64 oriented the same as the tines 60. The plates 37 and 40 are so placed as to align

holes

51, 53 and 55 with

holes

57, 59 and 61, respectively, and to insure the proper orientation of the plates, the plate 37 has a pair of

notches

65 and 66 which are aligned with a pair of

notches

67 and 68 of the plate 40 and which are engaged by suitable projections, not shown, in the shell 20. It will be understood that the

plates

38 and 39 are formed in a similar fashion. Thus, in a first row of holes in the plate 38, the tines may extend downwardly and to the left at a 45 angle and in the plate 39, the tines may extend upwardly and to the right at a 45 angle.

The opposite orientation of tines of adjacent rows is advantageous in equalizing any transverse forces exerted when the filter pin contact elements are installed, and also reduces cost. The plates can be readily rotated and flipped before forming so that one die, artwork master or the like can be used in circular connectors. One artwork is all that is required in circular connectors where holes are symmetrical about the centerline or in rectangular connectors where the holes are symmetrical.

It is noted that each of the plates 37-40 can be readily formed by a stamping operation or by an etching process. After forming the plates, the tines may be bent by appropriate forming operations.

It should be noted that the plates 37-40 are sandwiched between facing surfaces 69 and 70 of the

members

15 and 16 which serve to dissipate heat, a peripheral edge portion of the plate 37 being firmly engaged with a shoulder 71 of the shell member 20. Preferably, a relatively thicker metal backing plate 72 may be interposed between the plate 40 and the surface 70, an outer peripheral edge portion of the plate 72 being engaged by an end surface 73 of the insert 21.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. In an electrical connector, a laminated contact element comprising a plurality of thin metal plates each having a hole therein and each having a single integral resilient tine projecting from an edge portion of said hold, said holes being aligned for engagement of said tines with a contact extended therethrough, said tines being in angularly spaced relation, and each of said tines having a length dimension substantially greater than the radius of said aligned holes.

2. In an electrical connector as defined in claim 1, said tines projecting axially in the same direction with the tine of at least one plate extending through the hole of at least one other plate.

3. In an electrical connector as defined in claim 1, each of said plates having a plurality of additional holes therein and a single integral tine projecting from an edge portion of each of said additional holes and having a length dimension substantially greater than the radius thereof, said additional holes being aligned for engagement of said tines with additional contacts extended therethrough.

4. In an electrical connector as defined in claim 3, the orientation of certain of said tines with respect to the corresponding holes of each plate being opposite the orientation of others of said tines with respect to the corresponding holes of the same plate.

5. In an electrical connector as defined in claim 1, a pair of support members having facing surfaces with said laminated contact element being sandwiched therebetween, said support members having passages aligned with said holes.

6. In an electrical connector as defined in claim 1, support means for receiving said plates, said support means and said plates having cooperating alignment means for aligning said holes.

7. In an electrical connector as defined in claim 6, said alignment means being arranged to position said tines in equiangularly spaced relation.

8. In an electrical connector as defined in claim 1, a filter pin contact unit extended through said aligned holes and having an outer generally cylindrical electrode engaged by said tines.

9. In an electrical connector as defined in claim 1, there being at least three of said plates to provide at least three of said tines for engagement with a contact, said tines being in equiangularly spaced relation, whereby to obtain a centering action.

10. In an electrical connector as defined in claim 1, each of said tines having an outwardly bent terminal end portion.