Electrical Contact Pins

Abstract

An electrical contact pin construction is provided which is particularly suited for use in circuits of railroad cars which are coupled and uncoupled and which cannot have exposed electrically live contact pins, and which includes a slidably mounted electrical contact pin with a readily replaceable contact accessible for replacement without the necessity for disassembly of the pin or of the housing in which the contact pin is mounted, a watertight construction being provided by sealing the contact pin.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to electrical contact pins and more particularly to such pins having a readily replaceable contact and with provisions for preventing access of water.

2. Description of the Prior Art

The use of automatic coupling and uncoupling equipment for railroad cars is well known and electrification of railroad cars by means of various contact elements between cars operated in conjunction with automatic coupling and uncoupling equipment is also well known. In the previously available circuit control apparatus live contact pins or elements are exposed to the weather when the cars are uncoupled and present the danger of electrical shock and easy susceptibility to damage.

In my prior application for Electrical Circuit Control Apparatus, filed May 19, 1970, Ser. No. 38,775, now U.S. Pat. No. 3,646,498, an improved construction for such usage is disclosed but in that construction the replacement of the contacts requires extensive disassembly for pin removal or contact renewal.

While it has heretofore been proposed to provide replaceable electrical contacts the structures were not suited for rigorous service under severe weather conditions, required special tools or disassembly of the mounting structure or housing for removal of the pin for replacement, were not adaptable to small diameter contact pins, or had other shortcomings.

SUMMARY OF THE INVENTION

In accordance with the invention an electrical contact pin is disclosed, suitable for use on railroad equipment and the like which is subjected to severe weather conditions, which is suitable for a wide range of uses such as in the electrical circuit control apparatus in my prior application filed May 19, 1970, Ser. No. 38,775, but not restricted to such use, the structure including an insulating block with a bore having a wear resistant insert and within which a resiliently urged captive pin is mounted, the pin having a readily replaceable contact extending outwardly of the block with sealing against access of water.

It is the principal object of the invention to provide an improved movable contact pin, resiliently opposed as to its movement in one direction and resiliently urged but limited in its movement in the other direction.

It is a further object of the invention to provide, in a contact pin construction of the character aforesaid, a replaceable exposed contact, with sealing of the contact against access of water therealong.

Other objects and advantageous features of the invention will be apparent from the description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawing forming part thereof, in which:

FIG. 1 is a sectional view of a portion of a housing block with the contact pin of the invention mounted therein; and

FIG. 2 is a transverse sectional view taken approximately on the line 2--2 of FIG. 1.

It should, of course, be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now more particularly to the drawings, a supporting block 10 is shown which may provide a boundary wall of a housing (not shown). The block 10 is preferably composed of insulating material, such as an electric grade phenolic resinous composition of well known type, and has an outer face 11 and an inner face 12.

The block 10 has one or more sets of aligned bores 15 and 16, one set being provided for each contact pin, the outer end of the bore 15 terminating at the outer face 11 and extending to a shoulder 17, and the bore 16 extending from the shoulder 17 to the inner face 12.

Within the bore 15, and preferably with a press fit engagement therewith, a hollow cylindrical insert 18 is provided, extending beyond the face 11 to provide a stop and baffle and having an end wall 19 with a central bore 20 therethrough. The insert 18 is preferably of a water resistant electrical insulating synthetic plastic material with a low coefficient of friction for metallic surfaces to engage therewith. One particularly suitable material for the insert 18 is Teflon which has the further advantage of repelling ice formation and avoiding ice adherence at the end of the insert 18 beyond the face 11.

A contact pin 25 is provided having a central cylindrical section 26, slidable in the bores 16 and 20, and with a threaded end 27 on which a retainer washer 28, retainer nut 29, wire terminal 30 and retainer nut 31 are sequentially mounted.

The contact pin 25, at the end opposite to the threaded end 27, has an annular shoulder 33 which is slidable within the insert 18. A preloading compression spring 34, preferably of stainless steel, is interposed between the shoulder 33 and a metallic washer 32, preferably of brass which engages the end wall 19 of the insert 18.

The end 35 of the contact pin 25, beyond the shoulder 33, is preferably transversely slotted as at 36 and has an annular enlarged rim 37 to provide a compression type tang.

The contact pin 25 is preferably of brass with a silver plating coating.

A replaceable contact 40 is provided, preferably of brass with a silver plating coating, and of hollow cylindrical shape with an end wall 41 and with a central opening 42. The contact 40, at its innermost end preferably abuts the shoulder 33. The opening 42, at its inner end, is preferably provided with a groove 43 complemental in shape to the enlarged rim 37 for holding engagement with the rim 37.

The other end of the contact 40 is preferably provided with silver contact face 45 for engagement by a similar contact face (not shown) brought into engagement therewith.

The contact 40, on the periphery thereof and at a location to be within the insert 18, is provided with an annular groove 46 for the reception of a packing 47, preferably an O-ring, to prevent fluid leakage inwardly along the contact 40 and contact pin 25 when the same is used in an exposed location.

It will be noted that the contact pin 25 is permitted a limited movement inwardly for resilient engagement with the contact face 45 of another contact face (not shown).

The contact 40, held by the resilient engagement of the rim 37 in the groove 43, if worn or damaged, can be readily removed and replaced, if desired, merely by removing the old contact 40 and pressing on a new contact 40. No removal of stop nuts, wire terminals or contact pins or disturbance of circuit of the wiring package is required for renewal of a contact 40.

The insert 18 functions as a guide for the contact pin 25 and provides a relatively friction free surface for movement therealong of the packing ring 47. The compression fit between the packing ring 47 and the interior of the insert 18, and the engagement of the insert 18 in the bore 15 prevents fluid leakage to the interior of the coupling housing.

The projection of the insert 18 beyond the face 11 of the block 10 provides a stop to limit movement of another block thereagainst and provides a baffle around the contact 40 to aid in diverting moisture at the face 11 from entering the insert 18.

The insert 18 and projection of the insert 18 beyond the face 11 also aid in repelling formation of ice and prevents sticking of the contact assembly under freezing conditions.

When opposing contacts are brought together a constant force is maintained by the spring 34 in opposing directions. In a specific embodiment each contact 40 moves about three sixteenths of an inch upon coupling and contact engagement with the spring 34 compressed from a 10 to 12 pound force applying position up to an 18 to 20 pound force applying position.

Upon uncoupling, the contacts 40 separate and the spring 34 moves the assembly outwardly, as limited by the engagement of the washer 28 with the inner face 12, to its free or uncoupled position.

Claims

I claim:

1. Electrical circuit control apparatus comprising

block means having an inner and an outer face,

said block means having an opening between said faces,

an insert within said opening and having a central opening therethrough,

an electrically conductive contact pin member mounted in said opening in said insert and extending beyond said inner face for the connection of a wire terminal,

a stop member on said contact pin engageable with said inner face,

resilient means on said contact pin member and within said insert for normally urging said contact pin member toward said outer face, and

an electrically conductive contact member extending inwardly within said insert and outwardly beyond said outer face, and

interengaging portions on said contact member and said contact pin member detachably securing said contact member on said contact pin member,

said contact pin member having an annular shoulder slidable in said insert, and

said resilient means being a spring in engagement at one end with said shoulder and at the other end in said insert.

2. Electrical circuit control apparatus comprising

block means having an inner and an outer face,

said block means having an opening between said faces,

an insert within said opening and having a central opening therethrough,

an electrically conductive contact pin member mounted in said opening in said insert and extending beyond said inner face for the connection of a wire terminal,

a stop member on said contact pin engageable with said inner face,

resilient means on said contact pin member and within said insert for normally urging said contact pin member toward said outer face, and

an electrically conductive contact member extending inwardly within said insert and outwardly beyond said outer face, and

interengaging portions on said contact member and said contact pin member detachably securing said contact member on said contact pin member,

said insert and said block having portions with which said contact pin member is in engagement for guiding said contact pin member.

3. Electrical circuit control apparatus comprising

block means having an inner and an outer face,

said block means having an opening between said faces,

an insert within said opening and having a central opening therethrough with a portion facing outwardly at said front face,

an electrically conductive contact pin member mounted in said opening in said insert and extending beyond said inner face for the connection of a wire terminal,

a stop member on said contact pin engageable with said inner face,

resilient means on said contact pin member and within said insert for normally urging said contact pin member toward said outer face,

said contact pin member having a forward extension,

an electrically conductive contact member extending inwardly within said portion of said opening and freely insertable and removable with respect to said portion of said opening, and

interengaging members on said forward extension and said contact member detachably securing said contact member on said contact pin member.

4. Electrical circuit control apparatus as defined in claim 3 in which for said interengaging portions

said contact pin member has an annular shoulder slidable in said insert, and

said contact pin member has an extension disposed beyond said shoulder for reception in a complemental opening in said contact member.

5. Electrical circuit control apparatus as defined in claim 3 in which

said opening in said block means comprises aligned bores of different diameters and the end of one bore has a shoulder for engagement by said insert.

6. Electrical circuit control apparatus as defined in claim 4 in which

said extension has a slot extending inwardly from the end thereof and an annular rim for engagement in said contact member.

7. Electrical circuit control apparatus as defined in claim 3 in which

said insert contiguous to said outer face has an inner cylindrical surface, and

said contact member has an outer cylindrical surface in sliding engagement with said inner cylindrical surface.

8. Electrical circuit control apparatus as defined in claim 7 in which

one of said surfaces has a groove therein and a packing in said groove in engagement with the other of said surfaces for preventing fluid leakage along said contact member.

9. Electrical circuit control apparatus as defined in claim 7 in which

the outer surface of said contact member has a groove therein and a packing in said groove in engagement with the inner surface of said insert for preventing fluid leakage along said contact member.