US 3827005 A
An electrical connector including a male and a female terminal both stamped-formed from uniform thickness metal stock. The flat female terminal includes a folded cantilever spring arm which holds the male terminal against a contact point. The blade-like male terminal is inserted between the spring arm and the contact point and includes a groove for receiving the end of the folded cantilever spring arm to hold it in proper position when the terminals are assembled.
Claims available in
Description (OCR text may contain errors)
ELECTRICAL CONNECTOR The invention relates to electrical connectors of the type used to join daughter boards to mother boards. These types of connectors are disclosed in US. Pat. No. 2,502,253; US. Pat. No. 3,596,230 discloses a terminal related to one of the terminals of the present connector.
The present invention relates to an electrical connector having a fiat female terminal stamped from uniform thickness stock material and including a folded cantilever spring arm. The end of the spring arm is opposed a contact on the base of the female terminal. The electrical connector also includes a blade-like male terminal which is inserted between the spring arm of the female terminal and the contact point so that the spring arm is stressed and biases the blade against the contact point. Spring properties of the folded cantilever spring arm are determined by varying the width of the portions of the spring arm during the stamping operation.
Electrical connector is intended for use as a reliable yet inexpensive and easily manufactured connection system between a mother board and a daughter board. Such connections are needed in a variety of applications where inexpensive yet reliable connections are required where the daughter board must be removably mounted on the mother board.
Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention, of which there is one sheet.
IN THE DRAWINGS FIG. 1 is a perspective view illustrating a mother board with a number of blade terminals according to the invention mounted in a row and a daughter board having a number of female terminals according to the invention mounted in a row along the edge of the daughter board. The two boards are shown with the daughter in position to be mounted on the mother board;
FIG. 2 is a side view of the female terminal;
FIG. 3 is a view showing the underside of the daughter board with a female terminal mounted in holes formed through the daughter board;
FIG. 4 is a side view of a blade or male terminal according to the invention; and
FIG. 5 is a view illustrating the blade and female terminals engaged with one another.
The electrical connector disclosed herein includes an essentially flat female contact or terminal illustrated in FIG. 2 and a male contact or terminal 12 illustrated in FIG. 3. Both these terminals may be stamped-formed from uniform thickness sheet metal stock. The female terminal 10 includes a base portion 14 with a contact point 16 projecting to one edge from the base portion. Spring support 18 projects above one end of base 14 with folded cantilever spring arm 20 extending from the end of support 18 in the direction of the extension of base 14 and including a first leg 22, a reverse bend 24, and a leg portion 26. The free end of leg 26 is located at the crest of contactpoint 16. A pair of support and contact tines 28 extend from the end of base 14 and are bent out of the plane of the flat contact 10 as illustrated in FIG. 3.
A number of terminals 10 may be mounted on the edge of a daughter board 30 as indicated in FIG. 1 with the respective tines 28 fitted in holes formed through the thickness of the circuit board. FIG. 3 illustrates one such terminal 10 mounted on board 30 with the tines 28 extending through circuit board holes 32. Printed circuitry 34 is provided on the board 30 so that upon soldering the tines are secured to the board in electrical connection with the circuitry 34 as illustrated in FIG. 5. The solder is indicated by reference number 36.
A male terminal 12 includes a flat blade body 38 with a central longitudinally extending groove 40 running from one end of the body. A pair of lead-in shoulders 42 are provided to either side of the end of groove 40 to facilitate engagement of the terminal 12 with a female terminal 10. A mounting tab 44 is provided on the other, end of the terminal 12. Terminals 12 are positioned on a mother board 46 as illustrated in FIGS. 1 and 5 with tabs 44 extending through slots 48 in the mother board. The portion of the tab projecting through the mother board is secured in electrical connection with printed circuitry 50 on the bottom of the mother board 46 by a soldered connection 52. The blades 12 are mounted in a row on the mother board as illustrated in FIG. 1 with the blades oriented generally parallel to each other along the row and with the grooves 40 facing in the same direction. If desired, the portions of the blade 12 to either side of groove 40 may be bent in toward each other so that in transverse cross section the side of the terminal 12 illustrated in FIG. 4 is concave.
With the daughter board 30 positioned above mother board 46 as illustrated in FIG. 1, electrical connections between the two are formed by moving the daughter board down so that the female terminals 10 engage male terminals 12 projecting upwardly from the mother board. The adjacent curved surfaces of the reversed bends 24 and curved base corners 54 of the bases 14 form lead-ins in the terminals 10 between the spring arms 20 and the base. These lead-ins cooperate with the lead-ins 42 on male terminals 12 to assure that the male and female terminals mate properly with the second legs 26 of the female terminals fitted in and extending along the recesses 40 of the male terminals. Because the female and male terminals are mounted at degrees to each other, the central longitudinal portions of the male terminals are fitted within the slot 46 of the female terminals and, with further insertion, are forced past the contact points. The folded cantilever spring arms 20 are bent outwardly away from the bases 14 so that they are stressed and provide the desired contact pressure to form an electrical connection between the blades 12 and the contact points 16 of terminals 10.
Because the folded cantilever spring arm is formed of uniform thickness strip stock material, the spring properties of the arm are easily controlled by varying the width of the arm along its length, as illustrated in FIG. 2. The width of the leg 22 of the arm is decreased along its length away from the support 18. The width of the spring arm around bend 24 is constant and the width of the second leg 26 decreases along its length. By decreasing the width of the legs portions along the length of the spring, the spring leg portions are uniformly stressed when the male blade is inserted and a high spring contact pressure is achieved. Different spring properties may be obtained by varying the width of the spring arm along its length as desired. This is easily accomplished by changing the tooling used to stamp-form the female contact and does not require complicated folding or other operations inherent in the manufacture of other types of female contacts.
FIG. 5 illustrates the male and female contacts engaged with one another with the end 58 of the male terminal engaging one edge of spring support 18 and the second spring leg 26 lying within groove 40. The groove assures that the spring 20 is held in proper position on terminal 12. The second leg 26 ends opposite the contact point 16 to assure that the contact pressure is primarily applied to the male terminal opposite the point. A second groove like groove 40 may be provided on the reverse side of male terminal 12. The contact point 16 fits into this groove.
While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.
What I claim as my invention is:
1. An electrical connector including an essentially flat female terminal and a male terminal both formed from uniform thickness metal stock; the female terminal including a base, a contact point on one edge of the base, a spring support extending from said edge past the contact point, and a folded cantilever spring arm extending from the end of the spring support along a first leg past the contact point to a reverse bend,
around the bend, and then along a second leg between the base and first leg and ending immediately adjacent the contact point, the base and second leg defining a slot for the reception of the male terminal; the male terminal including a flat blade-like body with a leg receiving groove formed along the length of one side thereof; whereby the male terminal may be mated with the female terminal with the second leg fitted in said groove and the folded cantilever spring biasing the male terminal against the contact point to form an electrical connection between the terminals.
2. An electrical connector as in claim 1 wherein said male terminal includes a pair of lead-in surfaces to either side of the end of said groove; and the female terminal includes curved lead-in surfaces to either side of the mouth of said slot.
3. An electrical connector as in claim 2 wherein the surface of the male terminal including said slot is concave in a lateral cross section.