Zero insertion force electrical connector with reliable actuation member

[0001] 1. Field of the Invention

[0002] The present invention relates to a zero insertion force (ZIF) electrical connector, and particularly to a ZIF electrical connector for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB). The invention relates to a copending application Ser. No. 10/839,838 filed on May 5, 2004.

[0003] 2. Description of the Prior Art

[0004] Zero insertion force (ZIF) electrical connectors are well known in the computer industry and are used for electrically connecting electronic packages such as central processing units (CPUs) with circuit substrates such as printed circuit boards (PCBs). Pertinent examples of such connectors are disclosed in U.S. Pat. Nos. 6,544,065, 6,533,597, 6,508,659, 6,482,022, 6,406,317 and 6,280,223.

[0005] Normally, a conventional ZIF electrical connector comprises a base soldered to and electrically connected with a PCB, a cover slideably mounted on the base and having a CPU attached thereon, and an actuating device for actuating the cover to slide along the base. The CPU has a plurality of leads extending outside a bottom surface thereof and arranged in a rectangular array. The cover has a plurality of through holes arranged corresponding to the leads of the CPU. The base defines a plurality of receiving passageways arranged corresponding to the leads of the CPU, too. Each receiving passageways receives an electrical terminal therein. When the CPU socket is in an open position, the leads of the CPU extend through the corresponding through holes of the cover and are received in the corresponding passageways of the base. The leads of the CPU do not contact the corresponding electrical terminals, thereby the CPU is attached on the CPU socket with zero insertion force. The actuation device comprises an operation lever to facilitate manual handling by a user. When the operation lever is rotated toward and locked in a closed position, the cover is correspondingly driven to slide along the base, and the CPU socket reaches a closed position. The actuation device thus pushes the leads of the CPU into mechanical and electrical engagement with the electrical terminals.

[0006] Prior to attachment of the CPU onto the socket, the operation lever may be inadvertently positioned midway between the open position and the closed position. When the CPU is attached to the socket, the leads of the CPU are inserted directly into the electrical terminals of the base. The leads of the CPU and the terminals in the base are liable to be damaged, in which case the electrical engagements between the leads of the CPU and the corresponding electrical terminals may be impaired.

[0007] Hence, an electrical connector having an improved actuation device is desired to overcome the disadvantages of the related art.

[0008] Accordingly, it is an object of the present invention to provide a zero insertion force (ZIF) electrical connector having a actuation device that can automatically position itself to an open position prior to attachment of the CPU onto the connector.

[0009] To achieve the above object, a ZIF electrical connector in accordance with a preferred embodiment of the present invention comprises an insulating base mounted onto a circuit substrate such as a printed circuit board (PCB), a cover movably mounted onto the base, and an actuation member located between the cover and the base to move the cover with respect to the base. The base defines a T-shaped chamber in an end thereof, a bind hole in the same end and parallel with the longitudinal direction of the base, and a baffle at the end adjacent the chamber. The cover defines an opening in an end thereof. The actuation member comprises a driving member located in the chamber, a spring-holding shaft received in the bind hole of the base, a spring attached around an end of the spring-holding shaft. The driving member has a driving shaft and an operating lever engaging with the driving shaft at an end thereof. The driving shaft comprises a cam at an opposite end thereof, the cam engaging in the opening of the cover to move the cover when the driving shaft rotating. An end of the coil spring securely engages the spring-holding shaft and an opposite end of the spring abuts against the operating lever. Due to structural engagement between the actuation member and the base, said spring is deformed once the operating lever is moved in a halfway from a closed position to an open position of said actuation member, so as to resume itself to urge the actuation member toward said open position completely.

[0010] Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0015] Reference will now be made to the drawings to describe the present invention in detail.

[0016] The present invention provides a zero insertion force (ZIF) electrical connector for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB). As shown in FIG. 1, the connector 1 comprises an insulating base 10 soldered to and electrically connected with the PCB (not shown), a cover 20 movably mounted onto the base 10 for attaching the CPU (not shown) thereon, and an actuation member 3 assembled between the base 10 and the cover 20 to move the cover 20 with respect to the base 10.

[0017] The base 10 comprises a body portion 11, and a head portion 12 extending from a middle portion of an end of the body portion 11. The body portion 11 defined a generally rectangular window 110 in a center portion thereof. A multiplicity of passageways 111 is defined in the body portion 11, the passageways 111 arranged in a rectangular array around the window 110. Each passageway 111 receives an electrical contact (not shown) in a side thereof, and forming a receiving space in opposite side thereof adjacent the contact. A rectangular cavity 112 is defined in a middle of a portion of the body portion 11, the portion between the passageways 111 and the end of the body portion 11. A protrusion 113 extends from the body portion 11 in the cavity 112. An aperture 114 is defined in the protrusion 113, and communicates with the cavity 112. A metal clip 40 is accommodated in the aperture 114. A bore 401 is defined in a middle of the clip 40, and communicates with the cavity 112. A semicircular recess 115 is defined in the middle of the end of the body portion 11, which is in communication with the cavity 112.

[0018] The cover 20 has a shape similar to the body portion 11 of the base 10. A multiplicity of passageways 21 is defined in the cover 20, corresponding to the passageways 111 of the base 10. A metal frame 22 is embedded in a middle portion of an end of the cover 20. An opening 23 is defined in a middle of the frame 33, corresponding to the cavity 112 of the base 10.

[0019] A width of the head portion 12 is substantially one third of a width of the body portion 10. The head portion 12 defines a T-shaped chamber (not labeled), and a baffle 124 at a distal end thereof. The chamber comprises a shaft-receiving slot 121 extending in a longitudinal direction of the head portion 12, and a lever-receiving slot 122 perpendicular to the shaft-receiving slot 121. Referring to FIG. 2, there is shown an enlarged view of part of the head portion 12. The lever-receiving slot 122 is disposed in a free end of the head portion 12 adjacent the baffle 124. A first blind hole 123 parallel with the shaft-receiving slot 121 is defined in the free end of the head portion 12. A retention recess 126 is defined in the baffle 124, in alignment with the first blind hole 123. A second blind hole 125 (labeled in FIG. 1) is defined in a middle of the baffle 16, in alignment with the shaft-receiving slot 121. A hook 127 is formed at a side of the baffle 124 with a ramp 128 toward the lever-receiving slot 122.

[0020] Referring to FIG. 2 and in conjunction with FIG. 1, the actuation member 3 comprises a driving member 30, a spring 32 and a spring-holding shaft 34. The driving member 30 comprises a driving shaft 300 and an L-shaped operating lever 304 mated with the driving shaft 300 at an end thereof. A pin 303 coaxially extends from another end of the driving shaft 300. A semicircular projecting member 301 is formed partly around a middle portion of the driving shaft 300. A cam 302 is formed partly around the end of the driving shaft 300.

[0021] The spring 32 includes a main coil portion 322, a L-shaped first end 320 and a L-shaped second end 324 extending respectively two ends of the main coil portion 322. The L-shaped first end 320 is longer than the L-shaped second end 324. The spring 32 is assembled around the spring-holding shaft 34. The spring-holding shaft 34 includes a protruding cam 340 at an end thereof, a holding notch 342 defined at another end thereof, a block 344 for preventing the movement of the spring 32 to the protruding cam 340, and an oblique recess 346 defined between the block 344 and the cam 340.

[0022] In assembly, the spring 32 is firstly assembled around the spring-holding shaft 34. The L-shaped second end 324 of the spring 32 is retained in the holding notch 342. An edge of the block 344 abuts against an end adjacent the L-shaped first end 320 of the main coil portion 322. The spring-holding shaft 34 is received in the first blind hole 123. The L-shaped second end 324 of the spring 32 and the holding notch 342 of the shaft 34 is substantially in the blind hole 123. The L-shaped first end 320 is outside the blind hole 123. The oblique recess 346 is in alignment with the lever-receiving slot 122. The protruding cam 340 is mated with the retention recess 126 referencelly, which cannot rotate any more. The spring 32 and the spring-holding shaft 34 are thus positioned.

[0023] The L-shaped operating lever 304 is assembled on the driving shaft 300. The driving shaft 300 is received in the shaft-receiving slot 121. The pin 303 of the driving shaft 300 is inserted into the bore 401 of the metal clip 40. The metal clip 40 is accommodated in the aperture 114 of the protrusion 113. The end adjacent the operating level 304 of the driving shaft 300 engaging in the second blind hole 125 of the baffle 124. Thus, the actuation member 3 is assembled onto the base 10, with the cam 302 in the cavity 112, the L-shaped first end 320 abutting against a face of the operating lever 304. Then, the cover 20 is assembled onto the base 10, with the cam 302 engagingly in the opening 32 of the cover 3.

[0024] Referring to FIGS. 3 and 4, in use, the operating lever 304 is pushed from an open position to a closed position, thereby driving the driving shaft 300 to rotate. When the operating lever 304 is oriented at the open position, the passageways 21 of the cover 20 are located over corresponding receiving spaces of the base 10. Leads (not shown) of the CPU can be inserted through the passages 21 of the cover 20 into the receiving spaces of the base 10 with ZIF. Then the operating lever 304 is pushed to the closed position. Edges of the cam 302 engage with inner edges of the frame 22 of the cover 20 to move the cover 20 with respect to the base 10. The cover 20 pushes the leads of the CPU from corresponding receiving space into corresponding contacts. The hook 127 of the head portion 12 catches the operating lever 304, thereby positioning the operating lever 304 at the closed position. The connector 1 thus connects electrically the CPU with the PCB.

[0025] In above-mentioned operation of the operating lever 304, the spring 32 exerts a force on the operating lever 304. When the operating lever 304 is rotated from the closed position to the middle of the baffle 124, the main coil portion 322 is compressed all the time. When the operating lever 304 continues to be rotated toward the open position, the main coil portion 322 of the spring 32 is released gradually, and providing a force for the operating lever 304. The force assists in driving the operating lever 304 to rotate the open position. Therefore, when rotating from the middle portion of the baffle 124 toward the open position, the operating lever 304 can automatically rotate to the open position completely under compression of the spring 32, even if a force providing by an operator is insufficient. Consequently, the leads of the CPU are unlikely to interfere with the contacts of the connector 1, the CPU can reliably be assembled/detached onto/from the connector 1 with ZIF.

[0026] From the foregoing it will be recognized that the principles of the invention may be employed in various arrangements to obtain the features, advantages and benefits described above. It is to be understood, therefore, that even though numerous characteristics and advantages of the invention have been set forth together with details of the structure and function of the invention, this disclosure is to be considered as illustrative only. Various changes and modifications may be made in detail, especially in matters of size, shape and arrangements of parts, without departing from the spirit and scope of the invention as defined by the appended claims.