US 3748633 A
Description (OCR text may contain errors)
Lundergan [451 July 24, 1973 SQUARE POST CONNECTOR  Inventor: Robert Graham Lundergan, Camp Hill, Pa.
 Assignee: AMP Incorporated, Harrisburg, Pa.
 Filed: Jan. 24, 1972  Appl. No.:,220,022
 US. Cl. 339/217 S, 339/258 R  Int. Cl H0lr 9/08  Field of Search 339/217 R, 217 S,
339/256 R, 256 C, 256 A, 256 S, 256 SP, 256 T, 258 R, 258 C, 258 F, 258 P, 258 RR, 258 I S, 258 T, 95 R, 95 D, 221 R, 211
Primary Examiner-Marvin A. Champion Assistant ExaminerRobert A. Hafer Attorney-William J. Keating et al., Gerald K. Kita, John R. Flanagan and Allan B. Osborne  ABSTRACT The disclosure relates to an electrical terminal-for making electrical connection with a square post or the like within a housing, the housing having a cavity of slightly larger dimension than the normal dimension of the connector spring fingers. The housing includes a pair of shoulders on which hooks or projections at the end of the terminal spring fingers lock upon complete insertion of the terminal within the housing. One spring finger includes teeth thereon and the other spring finger includes a tooth mateable with the teeth on the first finger in order to allow both fingers to be pushed together to a great degree. The terminal is designed so that the innermost portion of one of the spring fingers is spaced from the innermost portion of the other of the spring fingers by an amount less than the cross-sectional area of the square post terminal to be inserted therein so that the projections or hooks will be locked firmly on the shoulders upon insertion of the square post.
1 Claim, 3 Drawing Figures SQUARE POST CONNECTOR BACKGROUND OF THE INVENTION This invention relates to an electrical terminal and,
more specifically, to a terminal which is latchable within a housing of a multi-contact connector and maintained in latched position by means of a post which is wider than the space between the innermost portions of the spring fingers of the connector.
Multi-contact connectors of various types have been well-known in the electrical art. Such connectors find great utility when used in connection with printed circuit boards of various types. One such electrical connecting device including terminals is depicted in U.S. Pat. No. 3,533,044 of Bauman et al. Terminals of the type depicted in the prior art have suffered the problem of being incapable of easy insertion into a housing or the like and at the same time being capable of being securely latched in position. This was caused by requiring that the spacing between the outer edges of the terminal and the housing be sufficient to allow the fork type spring connectors to flex inwardly during insertion. At the same time, it was required that the spring terminals be able to move outwardly in order that the hook members thereon be able to latch on to the shoulder of the housing in order to provide a lock therewith. For this reason, in one prior art device, it was necessary that the spring terminals diverge outwardly, therefore allowing contact with the housing only at the end portions of the spring terminals. The connection therefore often had a great deal of play and the electrical connection often provided a great deal of contact resistance or other problems related to this situation.
In accordance with the prsent invention, there is provided a terminal having resilient arms, capable of flexing toward each other, the end portion of one of the arms having an inwardly tooth and the other arm having teeth into which the saidtoothcan move, thereby allowing the arms to move closer together during insertion then was capable of prior art terminals of this type. The terminal is designed so that the distance between the innermost portions of the two arms is less than the cross-sectional dimension of the male post to be connected therewith and the arms are of only slightly smaller dimension than the inner dimension of the housing cavity into which they are to be locked. This causes a firm latching of the hooks on the fingers with the shoulders of the housing and eliminates most of the play between themale post and the terminal, thereby eliminating the problems as mensioned hereinabove.
It is therefore an object of this invention to provide a terminal capable of being latched in a housing without excessive play between the terminal and housing.
It is a further object of this invention to provide a terminal having a pair of spring arms, a portion of each of the spring arms being capable of extending across an axis between the two arms simultaneously.
The above objects and still further objects of the invention will immediately become apparent to those skilled in the art after consideration of the following preferred embodiment thereof, which is provided by way of example and not by way of limitation, wherein:
FIG. 1 is a section view of ahousing and the terminal in accordance with the present invention about to enter into the housing;
FIG. 2 is a cross-sectional view of a housing with the terminal of the present invention partially inserted therein; and
FIG. 3 is a cross-sectional view of a housing with the terminal of the present invention fully inserted therein prior to insertion of the male post.
Referring now to FIG. 1, there is shown a housing 1 having a plurality of cavities 3 which extend from the rearward face (which is on the right in FIG. 2) to the mating face, each cavity having end walls 5 and 7. Branches extend from the inner end of each caeity and open onto the upper and lower sides of the housing as viewed in FIG. 2 and onto the mating face, these branches defining forwardly facing shoulders 9, 11 for latching a terminal in the cavity. The terminal 13 includes wire 15 secured thereto by a crimp 17. The ter minal 13 includes a pair of arms 19 and 21 which are resilient and have a spring-like action. The arm 21 includes a tooth 23 which mates with two teeth 25 in the arm 19. The arms 19 and 21 also include hook portions 27 and 29.
With reference now to FIG. 2, there is a view of the partially inserted terminal. It can be seen that the arms 19 and 21 are moved together at the forward end thereof, the tooth 23 entering into the teeth 25 to allow movement of the terminal within the cavity 3. The terminal will continue to move inwardly toward the left as shown in FIG. 2 until it reaches the position as shown in FIG. 3, whereupon the hook portions 27 and 29 of the arms 19 and 21 are able to move outwardly due to the outward spring bias of the arms 19 and 21, thereby extending over the shoulders 9 and 11. The leftward movement on the terminal 13 is terminated by the housing restraining portions 30 and 31 which form window 32.
Referring now specifically to FIG. 3 it can be seen that, in the unbiased free state the arms 19 and 21 extend substantially parallel to .the walls 5 and 7 and closely adjacent thereto. The distance at that time between the inner edge of the tooth 23 and the inner edge of the teeth 25 as depicted by the space between the lines A-A will be smaller than the cross-section of a male post 35 as shown between the arrows BB. In a typical embodiment, for example, the space between the arrows A-A could be 0.015 inches whereas the space between the arrows BB could be 0.025 inches. As the male post 35 moves inwardly between the members 30 and 31 of the housing, the forward bevelled edges 37 and 39 thereof will move against tooth 25 of the arm 19 and tooth 23 of the arm 21, thereby forcing the hook portions 27 and 29 outwardly over the shoul- 'ders 9 and 11. Due to the resilient nature of the arms 19 and 21, the hooks 27 and 29 will be locked against the walls 5 and 7 and over the shoulders 9 and 11, thereby substantially eliminating any possible play between the male post 35 and the terminal 13.
It should be noted that the individual terminals are retained in their cavities, whether or not the connector is engaged with a row of terminal posts, by virtue of the engagement of the hooks 27, 29 with the shoulders 9, 11. After the connector is coupled to a row of terminal posts, it is impossible for the fingers of an individual terminal to be moved towards each other because of the presence of a post 35 between the fingers. This fea' ture confers an added degree of reliability upon termi nals and connectors in accordance with the invention.
It will be apparent from the foregoing specification that terminals in accordance with the invention can be manufactured in extremely small sizes by a straightforward stamping operation from brass or other metal stock and connectors in accordance with the invention can have their terminals located on closely spaced centers. Terminals in accordance with the invention can, for example, be stamped from brass strip having a thickness of 0.020 inches. The overall length of a terminal intended for a rectangular 0.022 and 0.025 inch terminal post is 0.600 inches and such terminals can be mounted in a connector housing on 0.10 inch centers.
Though the invention has been described with respect to a specific preferred embodiment thereof, many variations and modifications will immediately become apparent to those skilled in the art. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.
What is claimed is: g
1. A multi-contact electrical connector for forming disengageable electrical connections to a row of spaced-apart rigid terminal post s, said posts being mounted in, and extending from, a panel board or the like, said connector comprising:
a generally prismatic housing having a rearward face and a mating face, a plurality of contact-receiving cavities extending through said housing from said rearward face towards said mating face, said cavities having inner ends which are proximate to said mating face, said cavities having laterally extending branches at said inner ends said branches opening onto the side edges of said mating face and opening onto the sides of said housing which are on each side of said mating face, said branches defining shoulders directed towards said mating face,
a plurality of windows in said mating face, each of said windows communicating with, and being centrally located with respect to, one of said cavities,
a fork-type electrical contact terminal in each of said cavities, each of said terminals comprising a,
stamped member having a yoke portion and a pair of co-planar arms extending from said yoke portion, said arms having oppositely directed hook portions on their free ends, said hook portions extending into said branches and being latched against said shoulders to prevent'rearward movement of said terminal from said cavity, and each of said terminals being disposed against the rearwardly facing sides of one of said windows to prevent forward movement of said terminal through said cavity,
one of said arms having a single tooth and the other one of said arms having two teeth, said single tooth being between said two teeth, said teeth having contact crown portions, said contact crown portions'being spaced apart on opposite sides of said window and being adapted to engage a contact post extending through each window.