Solderless Spring Socket for Printed Circuit Board

The present relates to spring sockets which are inserted into plated through holes in a printed circuit board for the purpose of receiving leads from electronic components mounted on the board.

Spring sockets, also known as mini-spring sockets, are very small tubular metal members having interior springs for compressingly gripping male leads inserted therein. These types of sockets are inserted into plated through holes in a printed circuit board and retained therein by either soldering or by a frictional fit. Their use enables an electronic component to be easily plugged into and removed from the circuit board. Of the two types of sockets, the socket of the present invention is of the solderless type wherein retention is obtained frictionally; i.e., by a portion of the socket pressing outwardly against the walls of the plated through hole. Prior art sockets of this type include one produced and sold by Mark Eyelet, Inc. under the name HEXTITE pressfit sockets, M 3300 series. One end of the socket includes a hexagonal shaped exterior surface which engages the wall of the plated through hole for retention therein. Another prior art socket, sold by the Augat Company, is the HOLTITE series zero-profile solderless socket. A circular shaped end engages the hole wall to retain the socket therein. In both cases, retention is achieved by a frictional fit and in both cases, the sockets can be replaced if needed. However, the frictional fit is achieved passively and accordingly, the plated through hole size must be within tolerance for maximum benefit. Thus, it is now proposed to provide a socket having active spring members which will retain the socket in a wider range of hole sizes. It is further proposed to provide a socket wherein the section thereof which engages the plated through hole and the section which grips the lead inserted thereinto act independently of each other to avoid adversely effecting the other.

According to the present invention, a solderless spring socket is provided. The socket includes a first section having outwardly biased, resilient retention members for engaging the wall of a plated through hole to retain the socket in a printed circuit board. The socket further includes a second section having spring fingers biased inwardly to grip a lead from an electronic package inserted into the socket.

FIG. 1 is a view of one embodiment of a socket of the present invention;

FIG. 2 is a view of the socket in a plated through holes;

FIG. 3 is a sectioned view of the socket in a plated through hole;

FIG. 4 is a sectioned view of the socket in a larger diameter plated through hole;

FIG. 5 is a sectioned view of a lead inserted into the socket; and

FIG. 6 is a view of another embodiment of a socket of the present invention .

With reference to FIG. 1, socket 10 shown therein is made by the deep drawn manufacturing process. The preferred material is beryllium copper alloy with gold plating on the contact surfaces.

Socket 10 includes first section 12 at one end and second section 14 at another end. Section 12 is cylindrical and includes resilient retention members 16 which are struck and bent outwardly. Intermediate members 16 are wall portions 20. The free, outwardly facing edges 22 of section 12 are beveled to provide a guiding function.

Retention members 16 include bend portions 24 and elongated portions 26. Bend portions 24, which are curved rather than sharp, are adjacent the interface, indicated by reference numeral 30, between the two sections 12,14. As shown the bend portions 24 displace the elongated portions 26 outwardly from wall portions 20 while retaining a concentric relation therewith; i.e., the two bends are ninety degrees each.

The amount of displacement is slightly greater than the largest size plated through hole first section 12 can expect to see.

Wall portions 20 also include a ninety degree bend portion 32 but which displaces elongated portions 34 outwardly very slightly.

Second section 14 includes cylindrical root portion 40 (from which first section 12 extends) and resilient contact fingers 42 extending outwardly therefrom. Fingers 42 are defined by removing material (not shown) as indicated by slots 44. Fingers 42 are preloaded by being pushed inwardly as indicated by the collective taper of the fingers 42; i.e., free ends 46 are closed towards each other to define a narrowing space 48 within the confines of second section 14.

FIG. 2 shows socket 10 inserted into plated through hole 52 in circuit board 54. Substantially all of first section 12 is within hole 52 with retention members 16 pressing against wall 56 of hole 52 to retain socket 10 therein. Second section 14 extends below board 54 as shown.

FIGS. 3 and 4 provides a more clear view of retention members 16 engaging walls 56 of holes 52 and 60 (FIG. 4). The plating of holes 52,60 and the immediate surrounding area is indicated by reference numeral 58. FIGS. 3 and 4 also provides a clearer picture of the tapering second section 14 occasioned by the preloaded fingers 42.

FIG. 4 shows socket 10 in hole 60 in circuit board 54. As a comparison with FIG. 3 will show, hole 60 is larger than hole 56 and retention members 16 are not pressed inwardly to the extent they are with respect to the smaller diameter hole 56.

FIG. 5 shows lead 64 inserted into socket 10 in circuit board 54. As lead 64 enters narrowing space 48 in section 14, fingers 42 are resiliently pushed outwardly to provide a compressive force thereagainst. Section 12 and retention members 16 thereon are unaffected by the presence of lead 64.

FIG. 6 shows socket 70 which is another embodiment of the present invention. Socket 70 includes all of the structural features of socket 10 plus a integral funnel portion 72 to provide a more enhanced guide for a lead 64 being inserted. Wall portions 20 are joined together above retention members 16 to form the annular funnel portion 72. The outer diameter of funnel portion 72 may exceed or be less than the outer diameter defined by members 16.

As can be discerned from above, a solderless spring socket for printed circuit boards has been disclosed. The socket includes a first section which is positioned within the confines of a plated through hole in the board and which carry outwardly biased, resilient retention members. The retention members press against the wall of the hole to retain the socket in the board. A second section, connected to the first section, extends outwardly from the board and carries spring fingers which compressively grip a lead from an electronic package to make an electrical engagement therewith. Further, the socket includes a cylindrical root portion which isolates the functioning of the active components; i.e., the retention members and the spring fingers.