US 3323102 A
Description (OCR text may contain errors)
M y 1967 1.. c. MINOR 3,323,102
CONTACTS Filed March 21, 1966 FIGZ.
l9 i7 C ig M25 5 2L FIG-4.
59 5, IL a 44 7 United States Patent Ofilice 3,323,102 CONTACTS Leon C. Minor, Birmingham, Ala., assignor to Anderson Electric Corporation, Leeds, Ala., a corporation of Alabama Filed Mar. 21, 1966, Ser. No. 536,132 3 Claims. (Cl. 339-258) This is a continuation-in-part of the copending application for Plugboard Assembly, Ser. No. 387,465, filed Aug. 4, 1964.
This invention relates to contacts for engagement and electrical contact with patch pins of a plugboard or the like.
Among the several objects of the invention may be noted the provision of contacts adapted to make and maintain good electrical contact with a patch pin or the like; the provision of spring arm type contacts whichwipe respective patch pins as they are moved into engagement therewith; the provision of contacts of the class described which provide greater than point contact with patch pins or the like; the provision of contacts which insure relatively high contact pressure, low resistance electrical connections with plugboard pins; and the provision of contacts which avoid intermittent connections with patch pins due to the presence of contaminants and the like. Other objects and features will be in part apparent and in part pointed out hereinafter.
The invention accordingly comprises the constructions hereinafter described, the scope of the invention being i11- dicated in the following claims.
In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,
FIG. 1 is an elevation of a contact of this invention;
FIG. 2 is a view taken from the left end of FIG. 1;
FIG. 3 illustrates the contact of FIGS. 1 and 2 in engagement with a patch pin;
FIG. 4 is a plan view showing another contact embodiment of this invention; and
FIG. 5 is an end view taken from the left end of FIG. 4 and showing alternate positions of engagement between a patch pin and the contact of FIG. 4.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
Referring now to the drawings, a contact of this invention generally comprises, at one end, a hollow collar 1 shown secured to a metallic sleeve 3 by spot-welding or soldering. Projecting from collar 1 is an elongate fingerlike spring arm 5 of beryllium-copper or the like. The tip or free end 7 of the contact has a surface 9 for engagement with a patch pin 11 of a plugboard or the like for making electrical contact therewith.
Sleeve 3 and collar 1 are shown (FIG. 3) positioned in a hole or opening 17 of a contact board 19 with the sleeve engaging a shoulder 21 formed by a step in the hole 17. A terminal or pin 23 is crimp-connected to an electrical conductor 25 and the pin is positioned in sleeve 3 thereby electrically connecting the conductor 25 to the contact.
The contact arm 5 is preferably elongate and flexible to permit movement of the contact between its unfiexed FIG. 1 position and its flexed FIG. 3 position. Surface 9 on the free end or tip 7 of the contact is shaped to firmly engage a patch pin 11. Contact surface 9 is curved concavely transverse the length of arm 5 as shown at 27 and is curved convexly longitudinally of the length of the arm as shown at 29. The convex curve 29 extends across the concave curve 27 and the curved surfaces 27 and 29 together form the generally saddle-shape contact surface 9. Preferably, surface 27 has a radius of curvature which is 3,323,102 Patented May 30, 1967 slightly greater than that of the pin 11. For example, typical relative dimensions would be .094" as the radius of curvature of surface 27 and .077" for the radius of curvature of pin 11. Thus, surface 9 is in greater than point contact with the cylindrical side wall of the patch pin 11. The downwardly extending margins (as viewed in FIG. 2) of the concave surface 27 constitute shoulders 30 which prevent inadvertent disengagement between the surface 27 and a patch pin, the shoulders being particularly desirable when the contact is used in environments where it is subjected to vibrations and shocks which would tend to disengage the patch pin from the contact.
The pin 11 is mounted in a patch board 31 which is carried by a frame of a patch board assembly. The patch board 31 has a hole or opening 33 therethrough to re ceive the patch pin 11. The pin is connected to an electrical conductor shown at 35.
A plurality of contacts and pins are mounted in the contact board and patch board respectively so that contact surfaces 9 are opposite respective pins 11. The plugboard parts are arranged so that respective patch pins 7 are moved upwardly into contact with the contact member to slightly deflect the flexible spring contact from its FIG. 1 position to the position shown in FIG. 3. This deflection of arm 5 insures good contact between the pin 7 and the contact. The relative movement between patch pins 11 and the contacts of this invention, as the patch board 31 is moved into position relative to the contact board 19, is illustrated and described in detail in the aforesaid patent application.
The saddle-shape surface 7 of the end of the contact provides greater than point contact between the mating patch pins and the contacts of this invention which results in improved electrical contact between the parts and with good contact pressure and relatively high current carrying capacity. The convex curve 29 is desirable in that it permits post-patching in plugboard assemblies using these contacts, i.e., the insertion or removal of a pin after the contact board and patch board are positioned in registry.
Another embodiment of the contact of this invention is shown in FIGS. 4 and 5 to include a generally conical shape boss 39- which is substantially centered on both the concave and convex portions of the saddle-shape surface 9 at the free ends of the contact. A typical size for boss 39 is about .04" in diameter and about .01" in height. The boss projects downwardly (as viewed in FIG. 5) so that it will be in point contact with the surface of patch pin 11, while another point of contact is provided at either 41a or 41b depending on wheather the pin 11 (as it is moved into engagement with the contact surface 27) becomes aligned in the solid or dotted line position 11. Thus a redundant type of electrical contact is provided by this embodiment of the invention with two points of conductive contact being provided. Except for boss 39, the contact of FIGS. 4 and 5 is the same as the contact shown in FIGS. 1-3, therefore like reference numerals have been used for the other parts.
Because of boss 39 and its location, the force exerted against pin 11 due to deflection of the FIGS. 4 and 5 spring contact is applied across two relatively small contact areas and the resulting contact force per unit area is therefore substantially higher than is obtained with a corresponding deflection of the FIGS. 1-3 spring contact. This higher contact pressure will crush through or wipe oif almost any contaminants between the contact surface and the pin surface, thus avoiding loss of good electrical contact between the pin and contact. Therefore the FIGS. 4 and 5 contact is especially useful in areas subject to contamination by foreign particles, etc., and where the somewhat smaller overall contact area between the contact and a pin is suflicient for the desired current carrying capacity. Where contamination does not present any significant problem and/or higher current carrying capacity is desired, then the contact embodiment of FIGS. l-3 may be used.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. A contact particularly for engagement by a patch pin of a patch board, said contact comprising an elongate flexible spring arm adapted for mounting at one end thereof and having at its other and free end a tip including a contact surface engageable by the pin, said contact surface being curved concavely transverse the length of the arm and curved convexly longitudinally of the arm across the concave curve to present a saddle-shape contact surface at said tip for engagement by the pin, said contact surface including a boss of generally conical shape en-gageable by 4 said pin and substantially centrally positioned on the saddle-shape surface.
2. A contact as set forth in claim 1 in which the radius of curvature of said concavely curved surface is slightly greater than the radius of the patch pin.
3. A contact as set forth in claim 2 in which said one contact end comprises a hollow base for receiving a con ductor.
References Cited UNITED STATES PATENTS 1,595,003 8/1926 Downing 339-191 1,836,293 12/1931 Strahan 339258 X FOREIGN PATENTS 1,247,969 10/ 1960 France.
940,437 10/ 1963 Great Britain.
OTHER REFERENCES IBM Technical Disclosure Bulletin-Hayden vol. 2, No. 6, April 1960, '1 page.
MARVIN A. CHAMPION, Primary Examiner.
PATRICK A. CLIFFORD, Examiner.