Filtered Connector

Abstract

Electrical connector including low-pass filter contact units formed by inductance means of ferromagnetic material and capacitance sleeve means of dielectric material on a central conductive portion; the capacitive sleeve means is preferably approximately the same diameter as the end portions of the contact unit to provide a relatively thin unit while obtaining highly effective filtering. The units are readily assembled and each unit is independently removable from and re-installable in a contact passage of a support body. Curved tines extend inwardly from openings in a common ground plate to wipingly engage arcuately spaced portions of an outer conductive sleeve during installation and removal, insuring excellent electrical contact. Preferably, the contact plate is of a thin resilient metal and is engaged by one or two backing plates.

Parent Case Text

This application is a continuation of our prior applications Ser. Nos. 55,939, filed July 17, 1970; 860,175, filed Sept. 19, 1969; and 584,745, filed Oct. 16, 1966, all abandoned.

Description

The present invention relates to a filtered connector.

A broad object of the invention is to provide a filtered connector utilizing poke-home or removable contacts.

The connector is used in various installations such as, for example, in instruments enclosed in a case or cabinet of conductive material, such as aluminum. An external conductor or cable leads to the cabinet and connects with the filtered connector and other conductor or conductors lead from the connector to components within the case. The case is grounded, and means are provided for connecting the connector with the case and thus grounding it. The connector filters out high frequency noise which is diverted to ground, allowing only the direct current and low frequency alternating current signals to pass through the connector. Heretofore there has not been a successful and practical filtered connector utilizing removable contacts.

Another and broad object of the invention is to provide a filtered connector of poke-home character which has extremely good electrical characteristics.

Another object is to provide a filtered connector of the foregoing general character including pin contacts which can be easily and quickly inserted in place and removed therefrom, and which can be so inserted a great number of times without deletrious effects on the connector.

Other objects of the invention are to provide a filtered connector which is extremely small and inexpensive.

Other objects and advantges of the invention will appear from the following detail description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagrammatic illustration of an instrument in which the filtered connector of the present invention is incorporated, this figure also showing the filtered connector itself;

FIG. 2 is a diagram of a filtering means of known kind and which is incorporated in its essentials in the filtered connector of the present invention;

FIG. 3 is a diagram of the same filtering means of FIG. 2 but showing a modified arrangement of the elements and the specific arrangement incorporated in the connector of the present invention;

FIG. 4 is a perspective view of the main support structure of the filtered connector;

FIG. 5 is also a perspective view of the main support structure but taken from the side opposite that of FIG. 4;

FIG. 6 is a large scale sectional view taken at line 6-6 of FIG. 4 and also including a fragment of the cabinet in which the connector is mounted; and

FIG. 7 is a face view of the contact plate incorporated in the connector.

Referring now in detail to the drawings, attention is directed first to FIG. 1 which shows the connector of the invention incorporated in an instrument, at least portions of which are shown diagrammatically. The connector is indicated as a whole at 10 mounted in a case or cabinet 12 of conductive material such as aluminum, and grounded as indicated at 14. An external conductor 16 which is usually in the form of a cable detachably connects with the connector through a plug 18 in a known manner. Other conductors 20 are connected with the pin contacts of the connector, as referred to below, and lead to various instrumentalities in the case 12.

The connector of the invention includes filtering means incorporating the essentials represented in FIG. 2 where the conductor 16 leads to an inductance means 24 and then to the conductor 20 in the case. Capacitor means 25 are provided, including capacitors 26 and 28 connected with the conductors 16 and 20 and then to a common conductor 30 representing the case 12, and thereby to ground 14.

The filtering means shown in FIG. 3 is essentially the same as that of FIG. 2 but includes rearranged elements according to their arrangement in the connector of this invention. In the present instance, the capacitor 26 includes a first plate 32, the capacitor 28 includes a first plate 34, and the two capacitors together have a second and common plate 36, these plates being identified in the connector in the description hereinbelow.

FIGS. 4, 5 and 6 show the details of the construction of the connector. For convenience the connector will be identified as including a main support structure 38 and a plurality of pin contacts 40 removably mounted therein. The structure 38 includes an outer block 42 and an inner block 44 of dielectric material of known kind, preferably polycarbonate. Between the blocks is a central plate or foil 46 of good conductive material and preferably beryllium copper and of about .003 inches in thickness. This plate or foil is interposed between a pair of other plates 48 preferably of the same material but of substantially greater thickness, such as about .010 inch. The blocks 42, 44 and the plates 46, 48 are secured together in rigid assembly, as by housings or casings 50, 52 surrounding the peripheries of the respective blocks and having flanges 54, 56 extending beyond the housings and secured together as by rivets for securing the elements mentioned together. The plates 46, 48 also extend beyond the blocks 42, 44 and preferably to the edges of the flanges 54, 56 and are gripped therebetween. The support structure 38 is mounted in an aperture 58 (FIG. 6) in the case 12 and secured therein as by bolt-nut means 60 with the adjacent flange 56 in good electrical contact engagement with the wall of the case 12 so as to effectively ground the plate 46. Thus the plates 48 minimize the electrical impedance and increase the mechanical support.

The housing 52 preferably extends beyond the block 42 and forms a socket 62 for receiving the plug 18 of the cable, in the usual manner.

The structure 38 is provided with a plurality of through bores which serve as apertures or pin cavities 64 removably receiving the pin contacts 40, as well as other bores such as 65A, the following description however referring to the through bores 44 which are relatively large in number and of uniform size. The central through bores extend perpendicular to the lamination and of course form holes through all of the laminated elements. The size of the bores 64 relative to the pin contacts 40 are of importance and will be referred to again hereinbelow. The bore 64 in the block 42 includes a radially inwardly extending portion 67 and a counter-bore 68 at the front side of the block opening to the front, forming a forwardly facing shoulder 70. Inwardly of the portion 67 is another counter-bore 72 forming an inwardly facing shoulder 74. The hole has still another counter-bore 76 at its inner end extending to the adjacent plate 48 which also has a hole, 78, preferably of the same diameter as the counter-bore 76.

The hole in the block 44, designated 80, is of uniform diameter and of the same diameter as the counter-bore 72. The adjacent plate 48 has a hole 82 of the same diameter as the hole 80, and thus of smaller diameter than the hole 78 in the opposite plate 48. The central plate 46 also has a hole, 84, which is best shown in FIG. 7 which also shows the face of the central plate or foil 46. It also has holes 83 and 83A aligned with holes of the blocks 42, 44 to form the aperture 67 of the apertures 66. Referring to the holes 84 these are formed by initially cutting or punching them in the form of crosses, forming tines 86 which are then depressed or bent out of the plane of the plate, and they assume a shape calculated for producing a wiping action referred to below. That shape preferably is as indicated in FIG. 6 which is generally arcuate and preferably of a relatively long dimension in arcuate direction. It has been found that the greater the number of tines, the greater will be the effectiveness of the electrical contact between the tines and the pin contact.

The pin contact 40, removably disposed in each of various and selected ones of the apertures 64, as indicated, cooperates with the various dimensions of the holes making up the aperture 64. The pin contact 40 is made of good conductive material such as copper, which for manufacturing purposes is made of two parts. The body includes a central reduced portion 90 and end portions 98 and 94. The end portion 98, or front end, is adapted for engagement with the plug on the conductor 16 while the end portion 94, which may also be considered to be a collar is connected with the conductor 20. The rear end portion 94 has a hole or socket 95 into which the conductor 20 is inserted and is then crimped thereon for securement thereto.

The pin contact 40 at its forward end includes an enlargement or collar 96 forwardly of which is another reduced portion 98 forming a pin received in the plug 18. A retainer clip 100 is fitted on the pin 98 and secured thereto, adjacent to radially inwardly extending portion 67, having a radially yieldable, outwardly biased enlargement or bulbous portion 102.

After securing the conductor 20 to the pin contact 40, as indicated, the pin contact is inserted into the aperture from rear to front (right-to-left, FIG. 6), the retainer clip 100 collapsing or contracting in the portion 67 of the aperture, this movement continuing until the collar 96 engages the shoulder 74, whereupon the bulbous portion 102 passes by this restricted portion of the hole and expands, normally and yieldably retaining the pin contact in the aperture. Such a structure serves as a means for the insertion and removal of the pin contact and the impedance elements from the passageway in the blocks 42 and 44 of insulating material without separation of the blocks.

The inductance means 24 identified in FIGS. 2 and 3 is shown in FIG. 6 in the form of a ferrule 104 of ferrite, preferably made up of a plurality of sections butted end-to-end. This ferrule surrounds the reduced central portion 90 and confined endwise between the collar 96 and the rear end portion 94 which is secured to central portion 90 in any suitable manner such as by crimping. This ferrite ferrule produces an inductance in a known manner.

Outwardly of the ferrule 104 is a the capacitor means 25 identified above which includes the plates 32, 34, and 36 and a dielectric sleeve or cylinder 106 that has a central through bore and is made of a rigid ceramic material that is quite fragile. The plates are preferably of silver and may be a thin foil or coating applied to the inner and outer surfaces of the dielectric cylinder 106, the inner plates 32, 34 being spaced apart as indicated at 107 with end flanges 108 and 110 engaging the body of the pin and specifically the collar 96 and rear end portion 94. The outer plate 36 is of substantial length and forms an outer exposed contact element for engagement with the tines 86.

The physical construction of the pin contact is such that, from the collar 96 inwardly or rearwardly, it is substantially and effectively of uniform diameter. The dimensions of certain of the elements represented in FIG. 6 are exaggerated, the plates 32, 34, 36 being of insignificant thickness from a physical standpoint although however, of complete and uniform electrical integrity. The diameter of this inner or rearward large portion of the pin contact is only slightly less than the diameter of holes 80, 72 and in fact so dimensioned that the pin can be easily inserted and removed by the hand, but not wobbling therein or having appreciable play. As an example of the dimensions involved, the pin contact at its greatest diameter may be on the order of .085 inch, and .880 inch long.

The tines 86 extend inwardly beyond the diameter of the pin and upon insertion of the pin into the aperture, the outer capacitor plate 36 engages the tines with complete electrical contact therewith and to ground. The dimensions of the holes 80, 72 are important from the standpoint of physically positioning the pin contacts so that the pin element 98 is received in the plug 18 readily and without bending or distortion; it has the further advantage of establishing good electrical contact between the outer capacitor plate 36 and the tines 86. The counter-bore 76 provides space for yielding of the tines, but this counter-bore is of relatively small dimension axially. The tines 86 being biased radially inwardly constantly engage the outer capacitor plate 36 at all times; they produce a good wiping action thereon for good contact engagement, and the plurality of them circumferentially aids to the effectiveness of the contact engagement. The gripping of the central plate or foil 46 between the plates 48, and particularly the fact that they do so throughout the entire area thereof, has been found to produce an exceptional electrical conductive condition.

While a preferred form of the invention has been disclosed herein, it will be understood that changes may be made therein within the spirit and scope of the appended claims.

Claims

What is claimed is:

1. In an electrical connector having a plurality of individually removable and replaceable filtered contact units, a main support body comprising a pair of blocks of insulating material secured to each other and having a plurality of aligned contact passages therethrough; and electrical ground contact means comprising a planar layer of conductive material sandwiched between said pair of blocks and having openings aligned with the passages in said blocks; each of said filtered contact units including an elongated contact pin and filter means including a cylinder of fragile dielectric material, said contact pin having a first end portion adapted for connection with a mating connector member, a second end portion adapted for connection with an electrical conductor, and an elongated central portion interconnecting said end portions; said cylinder of fragile dielectric material having an outer diameter only slightly less than the diameter of a corresponding one of said support body passages and is positioned wholly within said support body passage for protection against damage; means securing each of said contact pins individually in said support body but allowing removal in the direction of said second end portion and reinsertion of each contact pin individually without requiring separation of the blocks of insulating material; said cylinder of dielectric material having a relatively thin foil conductive sleeve on the outer surface thereof and a central through bore surrounding said contact pin central portion; said electrical ground contact means having surfaces extending into each of said passages and yieldingly engaging the conductive sleeve on said filter means; said cylindrical filter means having opposite ends retained inside said support body when inserted for use and being removable without requiring separation of the blocks of insulating material.

2. The electrical connector of clalim 1 wherein said electrical ground contact means comprises a metal contact plate having resilient tines extending into each of the openings therein and slidingly engaging the conductive sleeve on said filter means.

3. An electrical connector comprising:

a main support body of insulating material having a plurality of parallel contact passages therethrough;

a contact pin comprising an elongated conductive body having first and second end portions adapted to meet with another contact pin and to be secured to a wire conductor respectively, and an elongated central portion interconnecting said first and second end portions and being located within a support body passage;

impedance means including a cylindrical body of fragile dielectric material surrounding the elongated central portion of said contact unit and an outer relatively thin foil conductive sleeve on the outer surface of said dielectric body; said cylinder of fragile dielectric material having an outer diameter only slightly less than the diameter of a corresponding one of said support body passages and is positioned wholly within said support body passage for protection against damage;

said contact pin being installable within said body means by inserting said first end portion into one end of a passage to move through said passage and to partially project from the opposite end thereof and being removable by withdrawal in the reverse direction;

means mounting said impedance means for insertion into and removal from said support body;

ground contact means in said body mounted in surrounding, contacting relationship with said outer conductive sleeve, and making wiping contact with said outer conductive sleeve during installation and removal of said impedance means; and

means for releasably locking said contact pin upon insertion of the pin in said passage, said locking means being releasable to permit withdrawal of said contact pin in said reverse direction.

4. The electrical connector of claim 3 wherein said body includes a pair of blocks having aligned openings defining said passages, and said ground contact means comprises a metal contact plate sandwiched between said pair of blocks, said contact plate having openings aligned with said passages in said pair of blocks, and a plurality of angularly spaced, radially inwardly extending tines in each of said openings thereof, said tines being curved for wiping engagement with angularly spaced portions of the outer surface of said outer conductive sleeve.

5. The electrical connector of claim 3 wherein said impedance means has a central bore into which the elongated central portion of said contact pin extends, and said contact pin further includes a pair of collars located at opposite ends of said central portion, said collars having diameters larger than the bore of said impedance means.

6. The electrical connector of claim 5 wherein the diameter of said outer conductive sleeve is approximately the same as the diameter of said collars and only slightly less than the diameter of said support body passage, and both of said collars are located in and positioned by the walls of said support body passage when said contact pin is locked in said passage.

7. In an electrical connector half that is useful in a two-part connector system having a plurality of individually removable and replaceable filtered contact units, said connector half including a main support body comprising a pair of blocks of insulating material secured to each other and having a plurality of aligned contact passages therethrough; and electrical ground contact means comprising a planar layer of conductive material sandwiched between said pair of blocks and having openings aligned with the passages in said blocks; each of said filtered contact units including an elongated contact pin and filter means including a cylinder of fragile dielectric material, said contact pin having a first end portion adapted for connection with a mating connector in the other part of said connector system, a second end portion adapted for connection with an electrical conductor, and an elongated central portion interconnecting said end portions; said cylinder of fragile dielectric material having an outer diameter only slightly less than the diameter of a corresponding one of said support body passages and is positioned wholly within said support body passage for protection against damage; means securing each of said contact pins individually in said support body but allowing removal in the direction of said second end portion and reinsertion of each contact pin individually without requiring separation of the blocks of insulating material, said cylinder of dielectric material having a relatively thin foil conductive sleeve on the outer surface thereof and a central through bore surrounding said contact pin central portion; said electrical ground contact means having surfaces extending into each of said passages and yieldingly engaging the conductive sleeve on said filter means; said cylindrical filter means having opposite ends retained inside said support body when inserted for use and being removable without requiring separation of the blocks of insulating material.

8. In an electrical connector half that is useful in a two-part connector system having a plurality of individually removable and replaceable filtered contact units, said connector half comprising:

a main support body of insulating material having a plurality of parallel contact support passages therethrough;

a contact pin comprising an elongated conductive body having first and second end portions adapted to meet with another contact pin in the other connector system part and to be secured to a wire conductor, respectively, and an elongated central portion interconnecting said first and second end portions and being located within a support passage;

impedance means including a cylindrical body of fragile dielectric material surrounding the elongated central portion of said contact unit and an outer relatively thin foil conductive sleeve on the outer surface of said dielectric body; said cylinder of fragile dielectric material having an outer diameter only slightly less than the diameter of a corresponding one of said support body passages and is positioned wholly within said support body passage for protection against damage;

said contact pin being installable within said body means by inserting said first end portion into one end of a passage to move through said passage and to partially project from the opposite end thereof and being removable by withdrawal in the reverse direction;

means mounting said impedance means for insertion into and removal from said support body;

ground contact means in said body including a plurality of angularly spaced, radially inwardly directed tines of conductive material mounted in surrounding, contacting relationship with said outer conductive sleeve, and making wiping contact with said outer conductive sleeve during installation and removal of said impedance means; and

means for releasably locking said contact pin upon insertion of the pin in said passage, said locking means being releasable to permit withdrawal of said contact pin in said reverse direction.

9. In an electrical connector having a plurality of individually removable and replaceable filtered contact units, a main support body comprising a pair of blocks of insulating material secured to each other and having a plurality of aligned contact passages therethrough; and electrical ground contact means comprising a planar layer of conductive material sandwiched between said pair of blocks and having openings aligned with the passages in said blocks; each of said filtered contact units including an elongated contact pin and filter means including a cylinder of fragile dielectric material, said contact pin having a first end portion adapted for connection with a mating connector member, a second end portion adapted for connection with an electrical conductor, and an elongated central portion interconnecting said end portions; means securing each of said contact pins individually in said support body but allowing removal in the direction of said second end portion and reinsertion of each contact pin individually without requiring separation of the blocks of insulating material; said cylinder of dielectric material having a conductive sleeve on the outer surface thereof and a central through bore surrounding said contact pin central portion; said electrical ground contact means having surfaces extending into each of said passages and yieldingly engaging the conductive sleeve on said filter means; said cylindrical filter means having opposite ends retained inside said support body when inserted for use and being removable without requiring separation of the blocks of insulating material, said electrical ground contact means comprises a metal contact plate having resilient tines extending into each of the openings and slidingly engaging the conductive sleeve on said filter means; and said contact pin securing means includes an enlarged, resilient, bulbous member and an annular collar member spaced therefrom by a predetermined distance, both of said members being located between said first end portion and said central portion of said contact pin; and said passageways have a first bore section having a first diameter sufficiently large to pass said bulbous and collar members and said cylindrical filter unit, and a second bore section of reduced diameter sufficiently large to pass the first end portion of said contact pin and to allow forced passage of said bulbous member but not said collar member, said second bore section extending along said predetermined distance between said bulbous and collar members.

10. The electrical connector of claim 9 wherein the diameter of said collar member is substantially the same size as the diameter of the first bore section, the second end section of the contact pin has a second collar member which has a diameter substantially the same size as the diameter of the first bore section so that the contact pin can be easily inserted and removed by hand, but not wobbling therein or having appreciable play; and the filter means is positioned between said collar members to be thereby removable and insertable concomitantly with removal and insertion of the associated contact pin.

11. The electrical connector of claim 10 wherein said fragile cylindrical dielectric body has an outer diameter only slightly less than the diameter of said support body passage and is positioned wholly within said support body passage for protection against damage.

12. In an electrical connector having a plurality of individually removable and replaceable filtered contact units, a main support body comprising a pair of blocks of insulating material secured to each other and having a plurality of aligned contact passages therethrough; said support body being enclosed within a metallic housing comprising forward and rearward portions each having a mounting flange formed integrally with both of said portions; an electrical ground contact means comprising a planar layer of conductive material sandwiched between said pair of blocks and having openings aligned with the passages in said blocks; each of said filtered contact units including an elongated contact pin and a cylindrical filter means, said contact pin having a first end portion adapted for connection with a mating connector member, a second end portion adapted for connection with an electrical conductor, and an elongated central portion interconnecting said end portions; means securing each of said contact pins individually in said support body but allowing removal in the direction of said second end portion and reinsertion of each contact pin individually without deleterious effects on said connector; said cylindrical filter means having a conductive sleeve on the outer surface thereof and a central through bore surrounding said contact pin central portion; said electrical ground contact means comprising a metal contact plate having resilient tines extending into each of said passages and slidingly and yieldingly engaging the conductive sleeve on said filter means; said metal contact plate having outer peripheral edges which are clamped between the flanges of said metallic housing to establish a low resistance electrical grounding connection between the metal contact plate of the connector and the mounting flange of said housing; said cylindrical filter means having opposite ends retained inside said support body when inserted for use and being removable without deleterious effects on said connector.

13. In an electrical connector having a plurality of individually removable and replaceable filtered contact units, a main support body comprising a pair of blocks of insulating material secured to each other and having a plurality of aligned contact passages therethrough; an electrical ground contact means comprising a planar layer of conductive material sandwiched between said pair of blocks and having openings aligned with the passages in said blocks; each of said filtered contact units including an elongated contact pin and a cylindrical filter means, said contact pin having a first end portion adapted for connection with a mating connector member, a second end portion adapted for connection with an electrical conductor, and an elongated central portion interconnecting said end portion means securing each of said contact pins individually in said support body but allowing removal in the direction of said second end portion and reinsertion of each contact pin individually without deleterious effects on said connector; said cylindrical filter means having a conductive sleeve on the outer surface thereof and a central through bore surrounding said contact pin central portion; said electrical ground contact means comprising a metal contact plate having resilient tines extending into each of said passages and slidingly and yieldingly engaging the conductive sleeve on said filter means, and a pair of metal backing plates which are both thicker than said metal contact plate, each of said backing plates having a large surface area abuttingly engaged with opposite sides of said contact plate and the abutting surfaces extending into close proximity to said tines; the metal backing plates of the ground contact means extending radially outwardly around the entire periphery of the insulating material; and the connector further including an outer casing having a surface portion of electrically conductive material generally in a plane transverse to said contact passages and in parallel facing and abutting relation to surface portions of at least one of said metal backing plates which extend beyond the periphery of the insulating material, and means establishing a low resistance electrical connection between said metal backing plates and said outer casing; said cylindrical filter means having opposite ends retained inside said support body when inserted for use and being removable without deleterious effects on said connector.