The invention relates generally to a socket assembly for connecting an electronic component to a circuit board and more particularly to a socket assembly used in conjunction with a connector header for providing removable connection of an integrated circuit to a circuit board.
In the electronics interconnection industry there is a need to efficiently and economically connect electronic components such as integrated circuits (IC) to printed circuit boards or similar component receiving boards. The integrated circuits are typically supported in a connector apparatus which can be easily inserted or removed from the circuit board without disturbing the remaining components on the board. The connector apparatus should also protect the integrated circuit from adverse handling conditions occasioned by replacement of components. These adverse conditions can both structurally and electrically damage the integrated circuit, rendering the component useless. Structural damage may be caused by rough or accidental mishandling of the fragile integrated circuit and electrical damage may be caused by the static electricity discharged by the handler.
Connector assemblies which are insertable and removable from circuit boards are known. These connectors employ a socket which accommodates the integrated circuit. The socket is inserted into a mating header which is mechanically and electrically secured to the circuit board. Typically the socket including the integrated circuit is inserted in a vertical orientation, that is the socket is brought down onto the header in a direction perpendicular to the plane of the circuit board. While this technique adequately provides for installation and removal without disturbing adjacent connections, clearance must be provided above the socket to allow for such vertical insertion and removal. Thus, when arranging plural circuit boards in parallel fashion, sufficient space must be provided between each to permit such clearance. Accordingly, the circuit boards cannot be placed in as close proximity as would be desirable for efficient use of the available space. Examples of the vertical insertion connectors are shown in U.S. Patent 3,880,493 issued April 29, 1975 and U.S. Patent 4,356,532 issued Oct. 26, 1982, the latter assigned to the assignee of the present invention. In each of these references the connector assembly is secured to the circuit board from above. In addition, the sockets of these connector assemblies include an open upper end which receives the integrated circuit. The integrated circuit remains exposed, both before and after connection to the circuit board and thus is subject to the external adverse conditions of handling.
The electronics industry has also seen the use of socket assemblies which provide for insertion and removal of an integrated circuit along a direction parallel to the plane of the circuit board. One such assembly is shown in U.S. Patent 4,380,360 issued April 19, 1983. In such assemblies, an integrated circuit holder is mechanically and electrically, permanently secured to a circuit board. The holder has a side opening which permits slidable receipt of an integrated circuit cartridge, in a direction parallel to the plane of the circuit board. While avoiding the need for increased space between circuit boards, the replaceable cartridge has an open side end which permits insertion of the integrated circuit into the cartridge. The integrated circuit is not fully enclosed until the removable cartridge is inserted into the fixed holder. Thus, the integrated circuit remains exposed and unprotected in the replaceable cartridge until the cartridge is inserted into the holder. As the holder is fixedly secured to the board there is no provision for the connection of an enclosed integrated circuit to a circuit board.
US-A-4397513 discloses a means for interconnecting an electronic component comprising a housing defining therein a cartridge receiving channel, the housing having a first open face in communication with said channel to permit access to said channel and a second face having contact accessing means for providing interconnection access, and a cartridge for receipt of said electronic component, the cartridge being dimensioned for slidable insertion with said channel, the cartridge having a first extent including thereon a plurality of terminals alignable with said contact accessing means of said housing, and a second extent for receipt of said electronic component, said contacts on said first extent being engageable with said electronic component via a pc-board.
According to the invention, there is provided an electrical interconnection assembly for providing electrical connection between a integrated circuit and a planar circuit board comprising:
a header having an insulative body and a plurality of electrical contacts extending therethrough, each of said electrical contacts having a first portion for securement to a generally planar printed circuit board and a second portion extending in a first direction parallel to the plane of said printed circuit board; and
a socket assembly removably securable to said header by movement slidably in said first direction along a surface of said printed circuit board, said socket assembly comprising:
The present invention provides for interconnection between an electrical component such as integrated circuit 10, Fig. 1, and a circuit board 12, Fig. 2. Integrated circuit 10 is a conventional dual-in-line package (DIP) element, including a semi-conductive, elongate body 14 and a plurality of spaced leads 16 extending from each longitudinal side thereof. Leads 16 are provided for interconnection of the active device contained in body 14 and circuit board 12. Circuit board 12 which may be a printed circuit board or similar member, is also of conventional construction, having a planar insulative body 17 and a plurality of holes 18 patterned thereon. Holes 18 facilitate connection of the integrated circuit 10 to circuit board 12 as will be described hereinafter.
Referring now to Figs. 2 and 3, a header 20, used in combination with the present invention is shown. Header 20 includes an elongate insulative body 22 which is typically formed of a suitable plastic such as glass or mineral filled polyethylene sulfide. Header body 22 includes a pair of legs 24 and 26 extending from each longitudinal end thereof. Legs 24 and 26 serve as latches to facilitate interconnection of the header 20 as will be described hereinafter. Header 20 further includes a plurality of spaced electrical contacts 28 supported in and extending through a central portion 29 of header body 22. Contacts 28 are pin-type contacts each having a first extent 30 which extends exteriorily of body 22 between legs 24 and 26, and a second extent 32 which is disposed at a right angle to first extent 30. The contacts 28 are positioned in two rows in header 20, the contacts 28 of one row being smaller than the contacts of the other row. Thus, as shown in Fig. 3, one row of contact second extents 31 will be above the other row of contact second extents 33.
Referring briefly to Fig. 7, header 20 is mounted to circuit board 12 with contact second extents 32 extending through the holes 18 thereof. The contact second extents 32 may be spot soldered or conventionally mechanically and electrically secured to circuit board 12 adjacent the holes 18. By securing the contact second extents 32 to circuit board 12, the header 20 will be fixedly positioned thereon. As above-described, contact first extents 30 of header 20 will extend at right angles to contact second extents 32 and thus extend parallel to the plane of circuit board 12. The lower row 33 of contact second extents 32 is positioned more proximately to circuit board 12 than the upper row 31.
With reference to Figs. 5 and 6, a socket assembly 40 of the present invention may be described. Socket assembly 40 is a two-piece member comprising a housing 42 and tray 44, both members being formed of a suitable insulative plastic material such as polyester. Housing 42 is a substantially rectangular member including a pair of opposed planar walls 42a and 42b and defining a central channel 46 therein. Housing 42 has an open front face 48, substantially perpendicular to planar walls 42a and 42b, which provides access to channel 46. Opposite front face 48 is a rear face 50 which includes a plurality of spaced apertures 52 therethrough. Apertures 52 are aligned in two rows and provide for accommodation of the two rows of contact first extents 30 of header 20 as will be described in further detail hereinbelow.
Tray 44 is constructed for matable slideable insertion into channel 46 of housing 42, the direction of insertion of tray 44 being along the arrow "A". Tray 44 is also substantially rectangular having forward extent 54 for accommodating the integrated circuit 10 and a rear extent 56 for facilitating interconnection. Forward extent 54 includes a cavity 58 which is exteriorly accessible from above, as shown in the drawings of Figs. 5 and 6. Cavity 58 receives and supports the integrated circuit 10. Thus, the integrated circuit 10 is inserted in tray 44 in a direction along arrow "B"; that direction being perpendicular to the direction of insertion of tray 44 (arrow "A").
Rear extent 56 supports therein a plurality of electrical terminals 60, positioned for connection with integrated circuit 10. Terminals 60 are elongate members each including a socket 62 at one end thereof and a tail 64 extending oppositely from socket 62. The terminals 60 are arranged in two rows in tray 44 for alignment with the two rows of apertures 52 of housing 42. Sockets 62 of terminals 60 are of conventional design including a pair of spring biased inwardly directed legs 62a and 62b which frictionally accommodate the pin-type first extents 30 of contacts 28 of header 20. Tails 64 extend from the sockets 62 and into the cavity 58 of forward extent 54. As oriented in Figs. 5 and 6, the upper row 60a of terminals 60 include tails 64a which extend into cavity 58 and are positioned along one side thereof, that side being adjacent sockets 62., The lower row 60b of terminals 60 have tails 64b which extend along the lower surface 44a of tray 44 to the opposite side of cavity 58. Both of tails 64a and 64b have cantilevered end extents 65 which extend into cavity 58. Cantilevered end extents 65 can be of any conventional design, including a dual beam extent as shown in Figs. 5 and 7 or an alternate single beam extent as shown in Fig. 6.
As shown in Fig. 5, the integrated circuit 10 is inserted into cavity 58 along the direction of arrow "B". The opposed leads 16 are placed in electrical engagement with the cantilevered end extents 65 of terminals 60, thus placing the integrated circuit 10 in electrical contact with the terminals 60. In order to assure proper electrical engagement the leads 16 may be vapor phase soldered or otherwise suitably secured to the cantilevered end extents 65 of terminals 60. As further described herein-below, inasmuch as the integrated circuit 10 is fully enclosed by socket assembly 40, upon insertion of tray 44 into housing 42, more effective interfaces between the leads 16 and end extents 65 may be provided. For example, interfaces such as gold-to-gold may be employed in an enclosed connection where not feasible in exposed connections.
As above mentioned, tray 44 is slidably insertable into channel 46 of housing 42 along the direction of arrow "A". To assure proper engagement of housing 42 with tray 44, housing 42 includes two rows of windows 66 and 68 across each of the planar walls 42a and 42b. The first row of windows 66 is adjacent open face 48 and the second row of windows 68 is more rearwardly disposed. Engageable with each of windows 66 and 68 are spring extents 70 of terminals 60. Each of the spring extents 70 of terminals 60 takes the form of a tang which is struck and bent away from a portion of socket 62. As the tray 44 is inserted in housing 42, the spring extent 70 of each terminal 60 will deflect inwardly to permit passage of tray 44. Once the spring extent 70 is aligned with window 66, it will spring outwardly into window 66 to lock the tray 44 in position. The inclined position of spring extent 70 will permit further inward progression of tray 44 but will prohibit withdrawal thereof. The engagement of the spring extents 70 with windows 66 provides a pre-latched position to allow access to cavity 58 for insertion of the integrated circuit 10, yet prevents the tray 44 from falling out from the housing 42. As the tray 44 is further inserted into channel 46 of housing 42, the spring extent 70 will again deflect inwardly permitting such further insertion. Upon engagement with the second row of windows 68 the spring extents will spring outwardly and engage the windows 68. This will lock the tray 44 in closed position in housing 42. In this position, sockets 62 of terminals 60 will be adjacent to and aligned with apertures 52 of housing 42 (Fig. 7) and provide connection access for the contacts 28 of header 20. The tray 44 is locked into the channel 46 of housing 42, with integrated circuit 10 being electrically connected to terminals 60. The socket assembly 40 provides a full enclosure for integrated circuit 10, permitting handling of the socket assembly 40 without adversely effecting, either mechanically or electrically, the integrated circuit 10 housed therein.
Referring to Fig. 7, the insertion of the socket assembly 40 including the integrated circuit 10 may be described. The socket assembly 40, as above-described includes integrated circuit 10 loaded into tray 44 and the tray 44 inserted and locked into housing 42. Also, as above-described header 20 is secured to the circuit board 12. The socket assembly 40 is moved along one surface of circuit board 12 in a direction parallel thereto. As no vertical displacement (relative to circuit board 12) is needed for insertion, the socket assembly 40 may be inserted between two closely spaced circuit boards 12 and 13. As socket assembly 40 is inserted into header 20, the first extents 30 of contact 28 are received in sockets 62, providing electrical connection therebetween. A conventional cooperative locking mechanism on the header legs 24 and 26 and the housing 42, locks the socket assembly 40 onto the header 20.
In order to assure proper orientation of the socket assembly 40 with respect to header 20, polarization means is provided. In the preferred embodiment, the polarization means takes the form of a key 75 (Fig. 3) on each of legs 24 and 26 which engages a key-way 77 on either side of housing 42 (Fig. 5). This key and key-way arrangement prevents inverted insertion of socket assembly 40.
In repairing or replacing the integrated circuit 10 it may become necessary to remove the socket assembly 40 from header 20, without distributing the arrangement of circuit boards 12 and 13 or adjacent connections. Thus, a pair of opposed slots 80 are provided on opposite sides of housing 42 (Fig. 5). Slots 80 permit engagement of a insertion/removal tool (not shown) which facilitates removal of socket assembly 40. The insertion/removal tool is typically a finger-type tool which can be inserted between the spaced circuit boards 12 and 13. The fingers of the tool engage slots 80 on each side of housing 42.
Various other changes to the foregoing, specifically disclosed embodiments and practices will be evident to those skilled in the art. Accordingly, the foregoing preferred embodiments are intended in an illustrative and not in a limiting sense. The scope of the invention is set forth in the following claims.