Title:
ELECTRICAL TERMINAL
United States Patent 3865459


Abstract:
An electrical terminal comprises a U-shaped sheet metal body with slits or slots in the legs of the body extending inwardly from the edges thereof intermediate the opposite end of the body. These slits or slots define shoulders for abutting the surface of a printed circuit board. The sections of the legs below the slits or slots are flared outwardly so that as the terminal is inserted into the printed circuit board those leg lections will yield and then snap outwardly to underlie and provide a positive lock with the circuit board. The bight of the U-shaped body also has an outwardly struck projection that engages the printed circuit board to enhance stability of the terminal thereon. The trailing end of the body can be used as a wire wrap terminal or may be inserted into a connector.



Inventors:
MILLS TERENCE L
Application Number:
05/385404
Publication Date:
02/11/1975
Filing Date:
08/08/1973
Assignee:
MOLEX INC.
Primary Class:
Other Classes:
439/885, 439/888
International Classes:
H01R4/00; H01R4/14; H01R9/16; H01R12/04; H01R12/55; (IPC1-7): H01R9/06
Field of Search:
339/95R,217S,256SP,258S,276FS,17C,17L,213T
View Patent Images:
US Patent References:
3786402ELECTRICAL TERMINAL1974-01-15Horecky
3641477HOUSING FOR AN ELECTRICAL TERMINAL1972-02-08Plana
3535673ELECTRICAL GROUNDING TERMINAL1970-10-20Maltais et al.
3510829ELECTRICAL CONNECTOR1970-05-05Keller
3072880Snap-in terminal for panel1963-01-08Olsson
3047832Electrical socket contacts1962-07-31Deakin
2814024Prong receiving connector member1957-11-19Narozny



Primary Examiner:
Frazier, Roy D.
Assistant Examiner:
Hafer, Robert
Attorney, Agent or Firm:
Olson, Trexler, Wolters, Bushnell & Fosse
Claims:
The invention is claimed as follows

1. An electrical terminal comprising a one-piece elongated sheet metal body that defines a U-shaped channel with spaced apart legs that are joined by a bight, said channel-body having an entrance portion for insertion into an aperture in a printed circuit board and a trailing portion for connection to an electrical component, said entrance portion comprising shoulder means on said legs, and a slit formed in each of said legs at locations spaced from the corresponding shoulder means, said slit extending generally parallel to said shoulder means, the leg sections below said slit being flared outwardly with respect to the leg sections upon which said shoulder means are formed, to define edge portions, such that upon engagement of said entrance portion in said aperture, said leg sections will yield during passage through said aperture, but will snap into locking position upon passage therethrough, with said edge portions engaging one surface of said printed circuit board while said shoulder means is engaged with the other, opposed surface of said board.

2. A terminal according to claim 1 in which said leg sections taper toward the tip of said entrance section.

3. A terminal according to claim 1 in combination with an electrical connector having an entrance opening with a tongue therein that receives said trailing portion with the tongue between said legs whereby the tongue permits insertion of the terminal into the connector in a predetermined orientation relative thereto.

4. The combination as defined in claim 1 further including an outwardly struck detent means on said bight for engagement with said circuit board to aid in stabilizing said terminal on said circuit board.

5. The combination as defined in claim 4 wherein said detent means is received within said aperture and is in wedging engagement with the walls thereof to effect said stabilizing action.

6. The terminal as defined in claim 1 wherein said slits are spaced from said shoulder means a distance approximate the thickness of said printed circuit board.

7. The terminal as defined in claim 1 wherein said leg sections on said entrance portion below said shoulder have a lesser extent than said leg sections above said shoulder.

8. An electrical terminal comprising a one-piece elongated sheet metal body that defines a U-shaped channel with spaced apart legs that are joined by a bight, said channel-body having an entrance portion for insertion into an aperture in a printed circuit board and a trailing portion for connection to an electrical component, said entrance portion comprising cooperating means for engaging opposite sides of said printed circuit board to lock said body on said printed circuit board, said cooperating means including, shoulder means formed on each said leg and engageable with the upper surface of said board, and terminal leg sections spaced downwardly from said shoulder means and flared outwardly with respect to said leg sections upon which said shoulder means is defined, said outwardly flared leg sections yielding upon passage into said aperture and snapping into locking position for engaging the other side of said printed circuit board upon passage through said aperture, and an outwardly struck detent on said bight for reception in said aperture and for engaging the walls of said aperture in wedging contact to stabilize said terminal on said circuit board.

9. A terminal as defined in claim 8 wherein said leg includes a slit formed therein and spaced from said shoulder means, said leg sections below said slit defining said outwardly flared terminal leg sections.

10. A terminal as defined in claim 8 wherein each said leg includes a slot formed therein, which slot defines said shoulder means, and serves to space said outwardly flared terminal leg sections from said shoulder means.

Description:
CROSS REFERENCE TO RELATED APPLICATION

Reference is made to my copending application Ser. No. 293,001, filed Sept. 28, 1972, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to improvements in electrical terminals, more particularly terminals of the type adapted for insertion into printed circuit boards.

There are various types of terminals that are intended for use with printed circuit boards. In general these terminals are mounted on the printed circuit board after which all of the terminals are soldered in place. The assembly of these terminals with the printed circuit board should be capable of being carried out quickly and economically. Moreover, the inserted terminals should have a stable and strong construction so that subsequent handling or use of the printed circuit board will not easily damage the terminals.

In the prior art, the trailing ends of most of these terminals are designed for connection to only one type of circuit element, for example a socket-type connector, a wrap of wire, or the like. This tends to limit the flexibility of application of the terminal, requiring different terminals for different types of connections.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of this invention to provide an electrical terminal that snaps into and positively locks to a printed circuit board, thereby providing a stable positioning of the terminal with respect to the printed circuit board.

It is a further object of this invention to provide a terminal of the type stated that is of generally U-shaped cross-section to provide strength yet simplicity of design and low cost of manufacture.

It is another object of this invention to provide a terminal of the type stated that has a trailing end of a type that may serve as a wire wrap post or which may be inserted into a socket-type connector of the type designed for receiving so called square wire terminals.

A still further object of this invention is to provide a series of electrical terminals of the type stated which are produced in chain form on carrier strips at the opposite ends of the terminals, whereby the terminals are maintained in parallel relationship during handling thereof. The carrier strip at the entrance end of the terminal may then be broken off and the carrier strip at the opposite or trailing ends of the terminals may be used to support the terminals in parallel relation for simultaneous insertion of the terminals into respective holes in the printed circuit board.

Still another object of this invention is to provide a connector of generally known type but which differs uniquely in the provision of a tongue at the entrance to a socket opening therein whereby the tongue permits insertion of a terminal into the connector in a predetermined orientation relative thereto. This provides a polarizing feature for the connector relative thereto a group of terminals on a printed circuit board.

In accordance with the foregoing objects, the terminal of the present invention comprises a one-piece elongated sheet metal body that defines a U-shaped channel with spaced apart legs that are joined by a bight. The channel is open at its opposite ends and also open opposite to the bight. The channel shaped body has an entrance portion for insertion into a hole in a printed circuit board and a trailing portion for connection to an electrical component, such as a connector or a wrap of wire. The entrance portion further includes shoulder means on the legs that engages one side of the board to limit the insertion of the entrance portion into the board. To provide a positive lock for the terminal on the board, the entrance portion of the terminal includes a resilient structure that snaps into locking position on the other or printed wiring side of the board. This resilient structure may comprise sections of the legs of the channel that yield upon insertion into the hole and then snap outwardly as those leg sections move therepast. In addition, the backbone or bight of the channel includes an outwardly struck detent that engages the printed circuit board to enhance the stability of the terminal on the board. Consequently, the aforesaid leg sections, the outwardly struck detent, and the shoulder means all cooperate to lock the terminal in place in an exceedingly stable condition.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a terminal constructed in accordance with one embodiment of the present invention and with a fragmentary portion of the printed circuit board being shown in broken lines;

Fig. 2 is a side elevational view of the terminal in position on a printed circuit board, the latter being shown fragmentarily and in cross section;

FIG. 3 is a cross sectional view taken along line 3--3 of FIG. 2;

FIG. 4 is a top plan view of a series of terminals joined together by carrier strips;

Fig. 5 is an exploded perspective view of a connector and terminal of the present invention;

FIG. 6 is a view similar to FIG. 2 and showing a wrapped wire around the terminal;

FIG. 7 is a front elevation of a modified form of terminal according to this invention and shown inserted in a printed circuit board;

FIG. 8 is a sectional view taken along line 8--8 of FIG. 7;

FIG. 9 is a sectional view taken along line 9--9 of FIG. 8; and

FIG. 10 is a top plan view of a series of terminals of FIGS. 7-9 joined together by carrier strips.

DETAILED DESCRIPTION

Referring now in more detail to FIGS. 1-6 of the drawing, there is shown a terminal comprising a one-piece, elongated sheet metal body 2 of brass or other suitable resilient conductive material. The body 2 defines a U-shaped channel having longitudinally extending legs 4, 6 that are joined by a generally arcuate bight 8. The body 2 may be considered as having an entrance portion 10 for insertion into a hole 12 in a printed circuit board 14, and a trailing portion 16 for connection to a wire wrap 18 (FIG. 6), or alternatively for insertion into a connector 20 (FIG. 5).

Extending inwardly from the free edges 22 of the legs 4, 6 are slots 24, 24 of a width approximately the same as the thickness of the printed circuit board 14. These slots 24, 24 provide downwardly facing shoulders 26, 26 for engagement with the upper surface of the printed circuit board 14. It will be noted that the portions of the legs 4, 6 that are above the shoulders 26, 26 are approximately parallel. However, the leg sections 28, 28, 28 that are below the slots 24, 24 diverge outwardly whereby the free edges 30, 30 thereof are laterally of the free edges 22 of the leg sections above the shoulders 26, 26, as best seen in FIG. 3. The free edges 30, 30 of the leg sections 20, 28 are tapered in an arcuate fashion toward the tip 31 of the terminal to facilitate easy entrance of the terminal into the circuit board hole 12. Furthermore, the bight 8 is centrally formed with an outwardly struck detent 32, the lower edge 34 of which is substantially in the same plane as the shoulders 26, 26 and is also adapted to engage the upper surface of the printed board 14.

Upon insertion of the entrance portion 10 of the terminal into the hole 12 of the printed circuit board 14, the edge of the hole 12 urges the leg sections 28, 28 together until those leg sections pass the hole 12. At that time the leg sections 28, 28 will spring outwardly and underlie the printed circuit board 14, which underside contains the printed wiring on the circuit board. At the same time the shoulders 26, 26 and the edge 34 of the detent 32 will engage the top side of the printed circuit board. A positive lock of the terminal onto the circuit board is, therefore, provided. The shoulders 26, 26 cooperate with the detent 32 to support the terminal at three locations and thereby stabilize the terminal in position on the board 14.

As best seen in FIG. 4, the terminals are produced in chain form, namely by being formed with conventional mechanism that leaves two carrier strips 36, 38 that are parallel and which are joined respectively to the corresponding entrance and trailing ends of the bodies 2, at frangible lines of weakness 40 at which the carrier strips may ultimately be separated from the terminals. The carrier strips 36, 38 have holes 42 by which the strips and the being-formed terminals may be advanced through the forming machinery. Upon completion of the formation of the terminals, a number of them, together with the carrier strips 36, 38, may be wound into a supply roll for subsequent use. In such use, however, a desired number of terminals are withdrawn from the supply and both carrier strips are transversely severed to leave a group of parallel terminals with integral carrier strips. The lower carrier strip 38 may then be removed leaving the upper carrier strip 42 in place whereby the latter may be used to position all of the terminals simultaneously into a series of properly spaced holes in the printed circuit board. After the terminals are snapped into their respective holes, as previously described, the terminals along with other components of the circuit board may be soldered in accordance with known techniques. Before or after the soldering, the upper carrier strip 36 may be separated from the terminals. Both carrier strips are discarded as scrap.

If the terminal is to be used in conjunction with a wire wrap 18, the wire may be wrapped in the usual manner around the terminal whereby the sharp corners at the free edges 22, 22 will bite into the wire and enhance the conductive contact therewith. The wire wrap 18 may, however, be preformed and slipped over the upper end of the terminal, in which case the wire wrap 18 readily deforms somewhat in accordance with the cross sectional contour of the terminal.

In FIG. 5 the connector 20 may be of a known type that includes a plastic housing 44 that contains terminals (not shown) for engaging male terminals that extend into an entrance opening 46 of square or rectangular cross section. A connector 20 of this type is ordinarily used for so called "square pin" male terminals. However, the trailing portion 16 is compatible with the opening 46 whereby the trailing portion 16 may be inserted into the opening 46 just like a square male terminal pin. Moreover, the opening 46 may be integrally formed with a tongue 48. This tongue 48 acts to polarize connector 20 relative to a group of terminals of the type herein described because the terminals cannot be inserted into the openings 46 unless they are oriented so that the tongues 48 are received within the channels of the terminals.

In the form of the invention shown in FIG. 7-10 the terminal 2a comprises an elongated body having longitudinally extending legs 4a, 6a joined by a generally arcuate bight 8a. The terminal body thus has an entrance portion 10a for insertion into a hole 12a in a printed circuit board 14a and a trailing portion 16a for connection to a wire wrap, like in FIG. 6, or alternatively for insertion into the connector 20, previously described.

Extending inwardly from the free edges 22a of the legs 4a, 6a are downwardly facing shoulders 26a, 26a for engagement with the upper surface of the printed circuit board 14a. The portions of the legs 4a, 6a above the shoulders are substantially parallel. Spaced downwardly from the shoulders 26a, 26a an amount substantially the thickness of the circuit board 14a or very slightly greater, the legs are formed with slits 24a, 24a. These slits 24a, 24a extend from the free edges 22a, 22a over fractional parts of the respective legs and run generally parallel to the shoulders 26a, 26a. As a result of formation of the slits during manufacture of the terminal the resilient leg sections 50, 50 that are just below the slits 24a, 24a diverge laterally outwardly of the free edges 22a, 22a. Thus the upper edges of the leg sections 50, 50 (which are at the slits 24a, 24a) are flared laterally relative to the shoulders 26a, 26a. Also, the bight 8a has an outwardly struck, centrally located detent 32a, the centerline of which approximately coincides with the plane defined by the shoulders 26a, 26a.

Upon insertion of the entrance portion 10a into the circuit board 14a, the edge of the hole 12a urges the resilient leg sections 50, 50 together, with their elastic limits, until those leg sections pass the hole 12a. At that time the leg sections 50, 50 will snap outwardly so that their upper edges defined by the slits 24a, 24a, will engage the lower side of the printed circuit board 14a. The shoulders 26a, 26a, will engage the upper side of the board 14a adjacent to the hole 12a. Also, the detent 32a will wedge into the hole 12a opposite to the shoulders 26a, 26a and the upper edges of the leg sections 50, 50. Consequently, the shoulders 26a, 26a, the leg sections 50, 50 and the detent 32a cooperate to support the terminal in three regions and thereby stabilize the terminal in position on the circuit board 14a.

As seen in FIG. 10, the terminal 2a of FIGS. 7-9 is manufactured in a manner similar to that of the terminal of FIGS. 1-6. That is, the terminal bodies are produced in chain form with two carrier strips 36a, 38a, all as previously described. Likewise, the lower carrier strip 38a may be removed so that the upper carrier strip 36a may be used to mount a number of terminals 2a at one time into the board 14a after which the carrier strip 36a may be severed from the terminals 2a.

The terminal 2a may also be used in conjunction with a wire wrap around the trailing portion 16. Likewise, the terminal 2a may have its trailing portion 16a inserted into the compatible opening 46 in the housing 44 of FIG. 5 such that the tongues 48 serve as polarizers for a group of terminals.