US 3646504 A
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Description (OCR text may contain errors)
U States Fatent iCiasson  ELECTRICAL CONNECTQR  inventor: Edwin 0. Classon, Wallingford, Conn.
 Assignee: Litton Systems, inc, Beverly Hills, Calif.
 Filed: Oct. 17, 1969 211 Appl. No.: 867,17
 11.5. Ci. ..339/176MP,339/l71,,339/2175 [51} int. Ci ..H05r1/07  Field oiSearch ..339/l7 L, 17 LC, 17 LM, 17 F,
339/17 M, 176 M, 176 MP, 176 MP, 217 R, 217 S, 256 R; 29/630, 413, 418, 423
 Reierences Cited UNITED STATES PATENTS 2,908,775 10/1959 Gilbert ..200/2 2,995,617 8/1961 Maxirnoffetal ..174/l53 51 Feb. 29, 11972 OTHER PUBLlCATlONS Reliable Electrical Connectors, 1958, page 188. Switching Connector, IBM Tech. Disclosure, N. K. Perkins, Vol. 7 No.6, November 1964, page 424.
Primary ExaminerMarvin A. Champion Assistant Examiner-Lawrence J. Staab AttorneyEarl R. Evans, Robert H. Lentz, Alan C. Rose and Alfred B. Levine 1 1 ABSTRACT An electrical connector for printed circuit boards consisting of a series of contact members each having a curved contact section extending into the recess in an insulating block of generally cubical shape in which the printed circuit board is inserted and an external section provided with an integral terminal portion. The metallic contact member is in the form of an open loop and, being resilient, is mounted about the outer surface of the insulating block by spreading the ends of the loop to clear the locking protuberance formed on the bottom of said block. The curved contact section of the contact member forms a beam, the lower end of which is free to move as the beam is deformed by the insertion of the printed circuit board, and the pressure on the board contact or terminal decreases as the beam is deflected. As the circuit board is inserted into or withdrawn from the connector, the wiping action provides for good contact surfaces on the opposing contacts, and the withdrawal force required is greater than the force required to insert the circuit board in the connector.
6 Claims, 8 Drawing Figures PATENTEDmze 1972 SHEET 1 BF 2 15 FEGJ 1 F36. 4 1 FIG. 5
ELECTRICAL conniscron BACKGROUND OF THE INVENTION The invention relates to a multiple contact connector, particularly adapted for making a low resistance electrical connection to the conductors or terminals of an electrical unit such as a printed circuit board. Since these connectors are often made in small sizes, the mounting and replacement or assembly of the small contact members offer problems which the present invention is designed to overcome.
BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings,
FIGS. El and 2 are plan and side views,. respectively, drawn to an enlarged scale or" a printed circuit board connector embodying the invention;
FIG. 3 is a sectional perspective view of the connector shown in FIGS. I and 2;
FIG. 4 is a detailed perspective view of the individual contact member;
FIG. 5 is a detailed view of a modified form of contact member adapted for the connector shown in FIGS. 1-3;
FIG. 6 is a view similar to FIG. 3, illustrating a modification wherein the connector is provided with a switching contact; and
FIGS. 7 and 8 are top and side elevational views of an array of contacts formed from a sheet metal blank, in one preferred step of the manufacture.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-3 of the drawings, the invention is shown by way of example as embodied in a connector for a printed circuit board or similar terminal board. The connector comprises an insulating block 10 of generally cubical shape having a central recess II to receive a printed circuit board 12, the connector being shown about three times actual size (of one type) in FIGS. 1 and 2. The contact members are supported on one or both sides of the insulating block, which is provided with ridges 16 forming parallel grooves in which the contact members are disposed. In a subminiature connector, the spacing between contacts may be only a few thousandths of an inch. The insulating block is rounded at the points 17, 1711 at the mouth or top of the recess 11 and provided with protuberances or outwardly projecting ridges 18, 18a at the bottom edges opposite the mouth of the recess II.
As shown more clearly in FIG. 4, each contact member 15 is in the form of an open loop located in a single plane and having a straight intermediate section 26, curved or arcuate sections 21 and 22 shaped to fit snugly against the insulating connector block ill at the points 17, 17a and 18, 18a, an arched convex section 23 terminating in an offset or flattened tip 24 at one end of the contact member, and a terminal or solder tip 25 at the other end of the contact member. The terminal part 25 of the contact member is shown as perforated at the point 26 to receive a conductor or connecting lead. Since the contact member is external instead of being provided with a termination projecting through an opening in the bottom of the insulating block, obviously the terminal end may assume any desired shape. Furthermore the difficulty encountered in forming the holes in the connector block in the case of a miniature connector is avoided. The connector block may be molded economically in very small sizes.
The connector may be provided with bused or redundant contact members 2dr: as shown in FIG. 5. The contact member 29a consists of a pair of contact elements similar to the contact member 15 connected together by an integral end portion 28.
The contact members 15 are made of resilient metal and are mounted on or removed from the connector block I!) by spreading the ends of the contact loop until the curved section 22 can be snapped over the ridge or protuberance 13, 18a. The contact member is retained in position by positive contact with the block at the points 17, 17a and 18, 18a, and on the outer surface of the block, while allowing for complete freedom of movement of the arched contact section 23 of the contact member. This feature of the invention permits easy assembly, and also removal and replacement of individual contact members if required for field repair.
The shape and arrangement of the contact portion of the contact member 15 constitutes another important feature of the invention. As the terminal board 12 (see FIG. 6 is inserted in the connector, the convex or arched section 23 of the contact member is deflected and the offset or flattened tip 24 slides along the inner surface 363 of the recess 11. While the desired wiping action of the contact surfaces is obtained, the force applied to the conductors on the printed circuit board is lower than with the usual type of contact, and uniformity of the contact pressures from one contact to another is assured since the forces do not depend upon the usual preset contact configuration. In addition, the applied normal force or contact pressure decreases as the board is inserted, while adequate contact is maintained when the unit is subjected to vibration. Furthermore the friction between the board and connector contacts increases the withdrawal force required to remove the board from the connector, compared to the insertion force.
The deflection characteristic of the arched contact section 23 of the contact members allows the use of switching contacts in the connector. Thus as shown by the dotted lines 23a in FIG. 6, one or more pairs of opposed contacts may be so shaped as to make electrical contact when the printed circuit board is withdrawn from the connector.
As shown in FIGS. 7 and 8, in manufacture a plurality of contact members 15 may be punched from a metal sheet 33 with an integral skirt section 34. The blank is scored at the points 36 and 37 and, after shaping the contact members, the tip ends 35 are broken off. The contact members may then be inserted in the connector block 10 while attached to the skirt 1%, which is then separated by flexing the blank at the score line 36. This facilitates assembly, especially in the case of a small connector having minute delicate contact members.
It will be apparent that the invention provides a construction having outstanding advantages in respect to the form and arrangement of the improved contact members and the ease of assembly and replacement of the contact members in the insulating block. Individual contacts can be replaced without disturbing the other contacts. The invention provides complete flexibility of design in respect to contact spacing and termination, and for connectors to be used with either singlesided or double-sided printed circuit boards.
What is claimed is:
l. A multiple contact connector, comprising:
an insulating block of generally cubical shape having a cen tral recess with inside surfaces for receiving a conductor bearing terminal board;
a plurality of planar contact members each in the form of an open loop having upper and lower arcuate end portions disposed on opposite ends of a straight intermediate portion;
separate end portions extending from said upper arcuate end portions disposed inside said recess;
said block being grooved to position said contact members side by side on the outside surface of said block and said block having rounded upper and lower protuberances about which said upper and lower arcuate end portion snap for removably retaining said contact members thereon;
the inside end portions of each contact member being arched at the point of contact with said terminal board to provide a positive wiping contact with the conductors thereon; and
offset end portions connected to said arched inside end portions having sliding contact with said inside surface of said recess for supporting said arched inside end portions and for further removably retaining said contact members upon said block.
2. A multiple contact connector according to claim 1, in which said contact members are removably retained in position on said insulating block by the four point spring contact thereof including the contact of the offset end portions connected to said arched inside end portions, the contact of said upper arched portions about said upper rounded protuberances, the contact of said straight intermediate portions along said outside surface of said insulating block, and the: contact of said lower arcuate portions about said lower rounded protuberances.
3. A multiple contact connector according to ciaim 2, in which the contact members are arranged in two rows with the inside end portions thereof mounted on opposite inside surfaces of the central recess in said insulating block, and the arched sections of at least one opposing pair of contacts are in electrical contact when the terminal board is removed from the connector.
4. A multiple contact connector, comprising:
an insulating block of generally cubical shape having a central recess of rectangular cross section opening into the top face of said block to receive a terminal board;
said block having rounded protuberances on at least one upper and lower outside edge thereof adjacent to and opposite the opening of said central recess;
contact members on said insulating block;
said contact members each including an arched contact section extending within said recess;
a flattened end portion extending from said arched contact section of each contact member within said recess for slidable contact with the inside surface of said recess when the arched contact section of the contact member is depressed by the insertion of a terminal board in said connector;
said contact members each including an open loop having upper and lower arcuate portions engaging said upper and lower rounded protuberances on said block joined by a straight intermediate portion, wherein said upper and lower arcuate portions and said flattened end portions removably snap assemble said contact members in place upon said block.
5. An electricai connector, comprising;
an insulating cubical block with inner surfaces forming a recess in an upper surface, side surfaces, a lower surface, and rounded protuberances at the jointure of said upper and lower surfaces with said side surfaces;
contact members to be removably mounted upon said insulating block;
said contact members each including:
an end portion slidably engaging said inner surfaces of said insulating block of the electrical connector;
an arched portion integral with said end portion;
a curved portion integral with said arched portion engaging said rounded protuberance at the jointure of said upper surface and side surface;
a straight intermediate portion integral with said curved portion engaging said side surface;
a second curved portion integral with said intermediate portion engaging said rounded protuberance at the jointure of said lower surface and said side surface thereby interacting with said first mentioned curved portion for demountably securing said contact member to said insulating block through the four point contact therewith of said end portion, first curved portion, intermediate portion and second curved portion; and
a terminal end portion integral with said second curved portion of the contact member.
6. A multiple contact connector according to claim 4, additionally comprising:
a skirt section in the form of a flat plate integral with one end of said contact members beyond said lower arcuate portions for supporting said contact members in accurate alignment and for snap assembling said contact members in said insulatin block; and said contact mem ers being scored ad acent the point of at-