1. Field of the Invention
The present invention relates generally to electrical connectors. More particularly, the present invention relates to a method of and system for interconnecting a printed circuit board to the rear of an electrical socket or plug.
2. Description of the Prior Art
Present methods of and systems for terminating a printed circuit board to the rear of an electrical socket or plug connector include soldering the connector contact tails to the board. The purpose of the soldering operation is to provide electrical and mechanical connection. In some instances, the heat generated by the soldering process can adversely effect the connector and printed circuit board. As a result, the electrical performance of the interconnect can be irreparably destroyed or, at the least, significantly degraded. Performance degradation, of course, must be avoided in electronics devices that are used in avionics and other sensitive systems, especially where rigid specifications must be met.
Moreover, soldering can create a rigid connection between the components. When a member soldered to a printed circuit board is deformed due to tensile, compressive or torque forces acting on the member, those forces can be propagated or transferred into the substrate of the printed circuit board causing internal stress. The stress can then damage the substrate or the crystal lattice structure associated with the circuits on the printed circuit board resulting in damage to the device.
The present method solves the problems associated with soldering and rigid connections by providing an interconnect between a socket and a printed circuit board whereby the means for attaching the two components together is made without soldering or using other methods involving heat. Moreover, the present invention solves that problem without introducing new problems, such as causing internal stresses in the printed circuit board that can also result in performance degradation.
Solderless interconnects are not new. U.S. Pat. No. 4,799,904 to Sutcliffe, for example, discloses a cylindrical connector contact for an electrical socket that can be mated to a printed circuit board. The contact, like in the present invention, provides the means for attaching the socket to the printed circuit board. The contact is made of a conducting material so that there is electrical continuity between an electrical conductor inserted in the front end of the contact and the circuits on the printed circuit board. In Sutfliffe, the contact has a plurality of axially spaced “barbs” arranged in a purely circumferential direction on the distal or “tail” portion of the contact. Those barbs engage rings on the wall of a circuit board through hole thereby retaining the contact within the hole. The larger the diameter of the hole, the greater the number of rings and barbs that are needed to ensure adequate mechanical attachment. Sutcliffe teaches that at least two barbs and rings are required to achieve a stable electrical contact. To allow for dimensional tolerances to be relaxed, the tail includes an axial cut so that the tail portion becomes flexible, which could reduce internal stresses on the printed circuit board at the connection point.
There are several problems associated with the contact disclosed in Sutcliffe. First, it is difficult and expensive to manufacture barbs and rings with tolerances in the order of a few hundredths of an inch. Moreover, if the contact is inserted in the printed circuit board through hole too far, only one barb and ring may make contact, reducing the electrical continuity between the two components and also lowering the mechanical forces retaining the contact in the hole. Further, only a portion of barb actually makes contact with a ring inside the hole, which limits the amount of electricity that can be conducted between the two parts.
U.S. Pat. No. 4,374,607 to Bright et al. also discloses an interconnect that does not require soldering but, unlike Sutcliffe, uses axially spaced “undercuts” or teeth on the distal or tail portion of a pin contact to mate with corresponding axially spaced grooves on a socket. When inserted, the undercuts engage and retain the contact in the socket.
The problem with the pin contact disclosed in Bright et al. is that electrical conductivity is made at the very distal end of the contact, which would not be feasible if it were used to conduct electricity to a printed circuit board. Pin contacts used for printed circuit boards generally require electrical contact at or near the same point where mechanical attachment occurs. That type of connection is preferred in many cases because the tensile and compressive forces transmitted through the contact to the printed circuit board must be minimized, as noted above, to reduce internal stresses on the board. Internal stresses can damage the crystal structure of, for example, the logic circuits on the board and cause circuit failure.
U.S. Pat. No. 4,701,004 to Yohn discloses a solderless cylindrical retention clip for receiving an electrical contact pin of an electrical connector. The clip is inserted inside a bore hole. One end of the clip includes two cantilevered springs or lances projecting radially inward toward the longitudinal axis of the clip. The ends of the springs engage a shoulder or groove formed on a pin. The shoulder extends perpendicular to the longitudinal axis of the pin (i.e., radially).
One obvious problem with the retention clip disclosed in Yohn is that it is not designed to conduct electricity. So while a contact inserted in the clip is retained and prevented from moving in a direction longitudinal to the contact axis, no electrical signals are conducted through the clip to another system.
U.S. Pat. No. 4,050,772 to Birnholz et al. discloses a contact pin and printed circuit board through hole receptacle for receiving the contact and conducting electricity. The through hole receptacle includes a rectangular lip around the opening of the hole and an annular electrical contact surrounding the opening of the hole. Together, those components engage the rear shoulder of a flange at the top of a contact pin as it is inserted in the hole. Another portion of the through hole inside the hole engages a radially-extending shoulder of a barb on the shank of the contact.
The problem with the contact pin disclosed in Birnholz et al. is that the rigid metal barb of the contact forces the plastic hole apart during insertion of the contact. That can cause internal stresses within the printed circuit board in the vicinity of the through hole that can damage the performance of the device. Also, the contact through hole receptacle forms a rigid connection with the contact, which is disadvantageous in some applications as noted previously.
The various approaches described in the above-cited patents for making solderless interconnects have not been found to be totally satisfactory solutions. This is especially true in the context of electrical interconnects used in highly demanding applications like aircraft connectors.
In view of the foregoing, it should be apparent that there still exits a need in the art for a method and apparatus for electrically interconnecting an electrical socket and a printed circuit board in which there is good conductivity and retention between those components and wherein the means for interconnecting does not degrade the electrical performance of the device. It is, therefore, a primary object of this invention to provide a method and apparatus for interconnecting a printed circuit board to the rear of an electrical socket that does not require soldering or other methods involving heat.
More particularly, it is an object of this invention to provide a conducting contact or pin associated with an electrical socket that extends into and engages a conducting through hole on a printed circuit board without the need for soldering.
Still more particularly, it is an object of this invention to provide a conducting contact or pin associated with an electrical socket that extends into and engages a conducting through hole on a printed circuit board so that external forces acting on the socket or plug are not transferred through the contact point to the printed circuit board or vice versa and thereby cause damage to the device.
Another object of this invention to provide a contact receptacle in a printed circuit board through hole that has springs or flanges for engaging an undercut on a contact when the contact is inserted in the contact receptacle.
A further object of the present invention is to provide a contact insertable in a contact receptacle in a printed circuit board in which the point where those components touch provides longitudinal retention of the contact in the receptacle and also provides electrical continuity between the components.
Still another object of the present invention is to provide a contact and contact receptacle in a printed circuit board in which the contact minimizes the transfer of internal stresses between the electrical socket and the printed circuit board.
Briefly described, these and other objects of the invention are accomplished in accordance with its apparatus aspects by providing a contact associated with an electrical socket receptacle or plug assembly and a contact receptacle associated with a through hole on a printed circuit board assembly. Thus, the contact can be associated with either a plug or a socket. In either case, the contact has a proximate or front end with a cavity for receiving an electrical conductor of a plug, and a distal or rear end, also called a tail, formed with a circumferentially arranged undercut that engages the ends of one or more electrically conducting flanges that extend radially inward in the contact receptacle. The receptacle assembly can be any receptacle, including one adaptable for receiving a round, 14-conductor plug, and includes a front and rear shell and an insert slidably engaged inside the rear shell. The printed circuit board assembly includes a printed circuit board with one or more contact receptacles, rear insert, retainer spring, and chip capacitor board.
With these and other objects, advantages and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims and to the several drawings attached herein.
Referring now in detail to the drawings, wherein like parts are designated by like reference numerals throughout, there is illustrated in
In the context of the present invention, the word “socket” can be interchanged with “adapter” or “receptacle.” Those terms, and others commonly used in the art, refer generally to the female portion of an electrical interconnect. The word “plug” generally refers to the male portion of an electrical interconnect, although other terms are often used, including the general term “connector.” However, “connector” also refers generally to a physical connection or mating of electrical components. It is important to note that a receptacle or a plug can contain pin or socket contacts. The embodiment of the connector 100 illustrated in
In
The components of the receptacle 210 include the following. First, the receptacle 210 has an opening 211 at a front end that is substantially cylindrical. In the embodiment shown in
Next, the receptacle 210 includes a cylindrical, threaded front shell 212 that forms the opening 211. Obviously, the front shell 212 does not have to be threaded, as any method of attaching a plug to the shell 212 is contemplated, including, but not limited to, the use of a clamp ring (not shown). The front shell 212 is axially-aligned with a rear shell 214. The front shell 212 and rear shell 214 are axially separated by a flange 213 interposed between those components. In
Next, the receptacle 210 includes a socket insert 215, which in
As noted above, socket insert 215 includes at least one contact hole 216 (described below), for receiving a contact. The socket insert 215 will have one contact hole 216 for each electrical conductor associated with a mating plug (not shown). In
Next, the receptacle 210 includes a chip capacitor board 257. A retainer spring 256 is axially-aligned with and secures the chip capacitor board 257 to the rear of the socket insert 215. The retainer spring 256 also grounds the chip capacitor board 257 to the rear shell 215, which is preferably made of metal or metal allow so as to be electrically conductive. As shown in
Next, the receptacle 210 includes a rear insert seal 254 with at least one longitudinally-extending insert hole 255 (only the rear opening of the hole 255 is shown). In the embodiment shown in
Also shown in
The components of the printed circuit board assembly 120 include the following. First, the printed circuit board assembly 120 includes a printed circuit board 251. Integral to the printed circuit board 251 are one or more contact receptacles 252 and conductors 253. In the embodiment shown in
The contact receptacles 252 are electrically conducting through holes electrically connected to circuits integral to the printed circuit board 251. There will be one contact receptacle 252 axially-aligned with a corresponding contact hole 216, aperture 258 and insert hole 255. The contact receptacles 252 can be conventional through holes well known in the art. However, in the embodiment shown in
Turning now to
In
The contact tail 310 shown in
As shown in
In
As shown in
The method of assembling the above components involves the following steps. First, an appropriate amount of heat-activated adhesive is applied to the shaft of the contact 230 and inner surface of the rear shell 214 and allowed to dry. The alignment groove 218 on the retainer ring 217 is lined up with the alignment flange (not shown) on the rear shell 214 and then the socket insert 215 is slid inside the receptacle 210 until the forward edge of the socket insert 215 is aligned approximately with the forward edge of the front shell 212. The contacts 230 are then assembled in the socket insert 215 by inserting the contacts 230 through the contact holes 216. The adhesive is then heat cured for an appropriate amount of time. After curing, the chip capacitor board 257 is slid over the contact tails 310 of the contacts 230 until it bottoms on the socket insert 215. Then the retainer spring 256 is assembled around the chip capacitor board 257 until it bottoms on the rear of the socket insert 215. Next, the rear insert 254 is slid over the contact tails 310 of the contacts 230 until the shoulder bottoms on the rear face of the rear shell 214. Finally, the printed circuit board assembly 120 is attached by lining up the contact receptacles 252 with the contact tails 310 of the contacts 230 and applying pressure until the receptacle springs 408 click into the contact tail undercuts 402 and the printed circuit board assembly 120 is secured.
Although certain presently preferred embodiments of the present invention have been specifically described and shown herein, it will be apparent to those skilled in the art to which the invention pertains that many variations and modifications of the various embodiments shown and described herein may be made in light of the above teachings without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.
Number | Name | Date | Kind |
---|---|---|---|
3621445 | Horecky | Nov 1971 | A |
4050772 | Birnholz et al. | Sep 1977 | A |
4374607 | Bright et al. | Feb 1983 | A |
4515422 | Pritulsky | May 1985 | A |
4701004 | Yohn | Oct 1987 | A |
4720268 | Weiss | Jan 1988 | A |
4799904 | Sutcliffe | Jan 1989 | A |
4930200 | Brush et al. | Jun 1990 | A |
5101322 | Ghaem et al. | Mar 1992 | A |
5456616 | Fuerst et al. | Oct 1995 | A |
5885113 | Bricaud | Mar 1999 | A |
6247965 | Cummings et al. | Jun 2001 | B1 |
Number | Date | Country | |
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20040157500 A1 | Aug 2004 | US |