Abstract:
An electrical socket assembly having a socket cover slidably mounted to a socket base over a range of motion. The socket assembly also includes a drive plate mounted to a cam portion of the socket cover. The drive plate and socket cover have range limit elements that engage one another to limit opposite ends of the range of motion. The socket assembly includes a cam shaft that engages the socket cover, drive plate, and socket base. The cam shaft is rotatable across a range of motion between an unlocked position and a locked position to slide the socket cover with respect to the socket base.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to an electrical socket assembly. More particularly, the present invention relates to and electrical socket assembly with tabs in the socket cover that absorb forces delivered by a rotating cam. 
     Many large electronic devices, such as computers, use sockets to connect different electronic components. For example, pin grid array (PGA) sockets are used to connect electronic packages, such as processors, to printed circuit boards. PGA sockets facilitate electrical communication between a large number of pins on the processor and contacts on the circuit board. PGA sockets may utilize a plastic socket cover that is slidably movable on a plastic socket base between open and closed positions. A metal cam shaft is situated in a channel on the socket cover and extends through the socket cover and socket base. The cam shaft is rotated to actuate the sliding movement. The cam shaft has a rectangular stop extending therefrom that rotates along a semi-circle within the channel between opposite blocking features formed with the socket cover. When the stop engages a first blocking feature, the socket cover is in the open position, and when the stop engages the second blocking feature, the socket cover is in the closed position. 
     The cover has an array of pin holes configured to match an array of pins on the processor. Similarly, the socket base has an array of pin receiving chambers configured to accept the array of pins on the processor and connected to contact pads on the circuit board. The processor is mated to the socket by first placing the processor such that its pins slide into the pin holes of the socket cover. With the socket cover in the open position, the processor pins pass through the pin holes of the socket cover into the pin receiving chambers of the socket base, but are not electrically connected to the pin receiving chambers of the socket base. The cam shaft is rotated to slide the socket cover to the closed position which causes the processor pins to electrically connect to contacts in the pin receiving chambers in the socket base. 
     Hence, conventional sockets suffer from several drawbacks. When the cam shaft is rotated in the channel and engages the plastic blocking features, the cam shaft applies a torque force to the blocking features. However, if the cam shaft applies too much torque, then the cam shaft can cause the plastic blocking features and the surrounding plastic of the socket cover to strain and crack under the force. Many socket applications require more substantial force to effectively close the socket cover and thus conventional sockets cannot be used in such applications. 
     A need exists for an electrical socket that addresses the above noted problems and others experienced heretofore. 
     BRIEF SUMMARY OF THE INVENTION 
     Certain embodiments include an electrical socket assembly having a socket cover slidably mounted to a socket base over a range of motion. The socket assembly also includes a drive plate mounted to a cam portion of the socket cover. The drive plate and socket cover have range limit elements that engage one another to limit opposite ends of the range of motion. The socket assembly includes a cam shaft that engages the socket cover, drive plate, and socket base. The cam shaft is rotatable across a range of motion between an unlocked position and a locked position to slide the socket cover with respect to the socket base. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 illustrates a top isometric view of a socket assembly formed according to an embodiment of the present invention. 
     FIG. 2 illustrates a bottom isometric view of the socket assembly of FIG.  1 . 
     FIG. 3 illustrates a partial top isometric view of a socket cover formed according to an embodiment of the present invention. 
     FIG. 4 illustrates a partial top isometric view of a socket cover formed according to an embodiment of the present invention. 
     FIG. 5 illustrates an isometric view of a drive plate formed according to an embodiment of the present invention. 
     FIG. 6 illustrates a partial bottom isometric view of a socket cover formed according to embodiment of the present invention. 
     FIG. 7 illustrates an isometric view of a cam shaft formed according to an embodiment of the present invention. 
     The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2 illustrate isometric views of a socket assembly  10  formed according to an embodiment of the present invention. The socket assembly  10  includes an insulated socket cover  14  slidably mounted to an insulated socket base  18 . The socket base  18  has a body  70  that carries an array of receptacle contacts  22  (FIG. 1) extending therethrough. The socket cover  14  has an array of pin holes  26  (FIG. 2) that are aligned to be positioned above the array of receptacle contacts  22 . In operation, the socket assembly  10  is connected to an electronic component such as a circuit board (not shown) by soldering the receptacle contacts  22  to contact pads or traces on the circuit board. A processor (not shown) having an array of pins is then positioned on top of the socket cover  14  such that the pin holes  26  receive the pins. The pins of the processor extend into, and engage, the receptacle contacts  22  in the body  70  of the socket base  18 . 
     FIG. 3 illustrates a partial isometric view of the socket cover  14 . The socket cover  14  has a generally rectangular body  66  with a cam portion  30  extending from an end thereof. The cam portion  30  has a semicircular channel  34  that receives an indicator  62  and a cylindrical metal cam shaft  38 . The cam shaft  38  has a rectangular stop  42  formed with, and extending out from, a peripheral edge of the cam shaft  38 . The indicator  62  includes a circular ring  54  connected to a handle  58 . The ring  54  rests on a top surface  50  of the channel  34 . The cam shaft  38  extends through the ring  54  into the body  66  of the socket cover  14  and the body  70  of the socket base  18  (FIGS.  1  and  2 ). Arched first and second tabs  78  and  80  extend upward through the top surface  50  of the channel  34  at opposite ends thereof. The first and second tabs  78  and  80  are received between L-shaped guide posts  82  extending from out of the cam portion  30  and side walls  110  extending along the channel  34 . The first and second tabs  78  and  80  have stop engagement sides  90 . As the stop  42  engages the stop engagement side  90  of the first tab  78 , the handle  58  of the indicator  62  is proximate the second tab  80 . 
     The socket assembly  10  is shown in FIGS. 1 and 3 in an unlocked position where the socket cover  14  and socket body  18  are aligned such that the pins of the processor freely slide into and, are not bound in, the pin holes  26  of the socket cover  14 . An operator is able to determine that the socket assembly  10  is in the unlocked position because the stop  42  engages the stop engagement side  90  of the first tab  78 . As the handle  58  is rotated in the direction of arrow A about a rotational axis  74 , the cam shaft  38  is rotated in the direction of arrow A and engages the body  66  of the socket cover  14  and the body  70  (FIG. 1) of the socket base  18 . The cam shaft  38  pushes the body  66  of the socket cover  14  in the direction of arrow B with respect to the body  70  of the socket base  18 . The relative horizontal shifting between the socket cover  14  and the socket base  18  causes the pin holes  26  to shift out of alignment with the receptacle contacts  22  (FIG. 2) and bind the pins within the socket cover  14 . When the handle  58  has been rotated in the direction of arrow A to the point where the stop  42  is resisted by the stop engagement side  90  of the second tab  80  and the handle  58  is proximate the first tab  78 , the pins are fully bound in the pin holes  26 . Thus, the position of the stop  42  indicates to an operator that the socket assembly  10  is in a locked position and electrically connects the processor to the circuit board. Alternatively, to release the pins from the pin holes  26 , the indicator  62  is rotated about the rotational axis  74  in the direction of arrow C from the locked position to the unlocked position. 
     FIG. 7 illustrates an isometric view of the cam shaft  38  formed according to an embodiment of the present invention. The cam shaft  38  includes cylindrical upper and lower portions  35  and  39 . The upper portion  35  has a larger radius than the lower portion  39 . The upper portion  35  overlaps the lower portion  39  along the perimeter of the lower portion  39  except where the upper and lower portions  35  and  39  share a common wall  37  at a point in their respective perimeters. The upper portion  35  is received within the socket cover  14  (FIGS. 1 and 2) and the lower portion  39  is received within the socket base  18  (FIGS.  1  and  2 ). 
     FIG. 4 illustrates a partial top isometric view of the socket cover  14 . The socket cover  14  may be made of plastic. The cam portion  30  is shown with the cam shaft  38 , indicator  62 , and first and second tabs  78  and  80  removed (FIG.  1 ). The channel  34  includes an oval cam hole  94  that receives the upper portion  35  (FIG. 7) of the cam shaft  38 . Because the upper portion  35  is circular, the cam shaft  38  only engages the body  66  of the socket cover  14  at two segments  98  defining the narrowest portion of the cam hole  94 . During rotation, the cam shaft  38  thus applies torque forces to the plastic body  66  of the socket cover  14  at the two segments  98  that can cause the body  66  to strain and crack along the cam portion  30 . The channel  34  also includes first and second slots  102  and  106  located between the guide posts  82  and the side walls  110  to receive the first and second tabs  78  and  80  (FIG.  3 ), respectively. 
     FIG. 5 illustrates an isometric view of a drive plate  114  formed according to an embodiment of the present invention. The drive plate  114  may be made of metal and is rhomboid or trapezoidal in shape, but may be circular, rectangular, triangular, square, hexagonal, or some other shape. The drive plate  114  is configured to be received within the cam portion  30  of the socket cover  14  of FIGS. 1-4. The first and second tabs  78  and  80  are formed with, and extend upward perpendicularly from, a top surface  118  of the drive plate  114 . The first and second tabs  78  and  80  are located on opposite sides of a cam hole  122 . The oval cam hole  122  that is aligned with the cam hole  94  (FIG. 4) of the socket cover  14  to receive the upper portion  35  (FIG. 7) of the cam shaft  38  (FIGS.  1 - 3 ). Because the upper portion  35  is circular, the cam shaft  38  only engages the drive plate  114  at two segments  125  defining the narrowest portion of the cam hole  122 . The drive plate  114  also includes circular post holes  126  that receive posts  130  (FIG. 6) extending from the socket cover  14 . The drive plate  114  strengthens the cam portion  34  (FIG. 4) around the cam hole  94  (FIG. 4) and absorbs the torque forces at the two segments  125  which receive posts  130  (FIG. 6) formed on the socket cover  14 . 
     FIG. 6 illustrates a partial bottom isometric view of the socket cover  14 . The cam portion  30  includes a recessed area  134 . The posts  130  extend out from a bottom surface  138  of the recessed area  134 , and the first and second slots  102  and  106  and the cam hole  94  extend through the recessed area  134 . The recessed area  134  is rhomboid in shape and sized to receive the drive plate  114  of FIG.  5 . The recessed area  134  is partially defined by an end wall  154  of the cam portion  30  and has angled comers  150  extending along side walls  158  of the cam portion  30 . 
     During assembly, the drive plate  114  (FIG. 5) is press fitted into the recessed area  134  such that the top surface  118  (FIG. 5) of the drive plate  114  is pressed against the bottom surface  138 , the posts  130  are received in the post holes  126  (FIG. 5) and the first and second tabs  78  and  80  (FIG. 5) are received within the first and second slots  102  and  106 . Angled corners  146  (FIG. 5) of the drive plate  114  are tightly fit into corresponding angled comers  150  of the recessed area  134 . The cam shaft  38  (FIG. 3) is then positioned in the aligned cam holes  94  and  122  (FIG. 5) of the socket cover  14  and drive plate  114 , respectively. The upper portion  35  (FIG. 7) of the cam shaft  38  engages the socket cover  14  and the drive plate  114  and the lower portion  39  (FIG. 7) of the cam shaft  38  engages the socket base  18 . 
     In operation, as the cam shaft  38  (FIG. 8) is rotated, the larger-radiused upper portion  35  (FIG. 8) engages the drive plate  114  (FIG. 5) and the socket cover  14  and moves the drive plate  114  and the socket cover  14  relative to the socket base  18  (FIG. 1) as the lower portion  39  (FIG. 8) of the cam shaft  38  rotates within the socket base  18 . The forces created by the rotating cam shaft  38  are absorbed by, and distributed through, the drive plate  114  in order that less force is applied to the plastic cam portion  30 . Therefore, the drive plate  114  helps prevent the cam shaft  38  from straining or cracking the socket cover  14  at the cam portion  30 . Additionally, the posts  130  prevent the drive plate  114  from being partially rotated or twisted within the recessed area  134  and thus reduce the amount of force being distributed by the plate against the end wall  154  and the corners  150  along the side walls  158 . 
     Returning to FIG. 3, the torque forces delivered by the stop  42  of the cam shaft  38  to the plastic side walls  110  as the cam shaft  38  is rotated between the locked and unlocked positions over time would cause the side walls  110  to strain or crack. However, the first and second tabs  78  and  80  resist and absorb the torque forces of the cam shaft  38  as the cam shaft  38  is rotated within the channel  34  in the directions of arrows A and C. The torque forces are then distributed throughout the drive plate  114  (FIG. 5) in the recessed area  134  (FIG.  6 ). The first and second tabs  78  and  80  can easily withstand and absorb a strong torque force, for example, 10 in/lbs, without straining or cracking. Therefore, the first and second tabs  78  and  80  strengthen the cam portion  30  of the socket cover  14  and generally extend the life of the socket cover  14 . Additionally, the first and second tabs  78  and  80  serve as position assurance indicators to an operator to let the operator know whether the pins are fully locked or unlocked within the pin holes  26  of the socket cover  14 . 
     In an alternative embodiment, the first and second tabs  78  and  80  may be formed with the socket cover  14  and extend through slots in the drive plate  114 . In another embodiment, the drive plate  114  may be positioned on top of the cam portion  30  and receive the first and second tabs  78  and  80  through the slots. Alternatively, the drive plate  114  may be positioned on top of the cam portion  30  and have tabs extending into slots in the socket cover  14  and tabs that engage the cam shaft  38 . 
     In another alternative embodiment, the posts  130  may be located in different positions within the recessed area  134  and corresponding post holes  126  may be located in different positions in the drive plate  114 . For example, the posts  130  may be located closer to each other alongside the cam hole  94  and the corresponding post holes  126  located closer to each other alongside the cam hole  122 . 
     In another alternative embodiment, the recessed area  134  may have more than two posts  130  received in corresponding post holes  126  in the drive plate  114 . For example, the recessed area  134  may have four smaller posts  130  situated about the cam hole  94 . Similarly, the drive plate  114  would have corresponding smaller post holes  126  situated about the cam hole  122  to receive the posts  130 . 
     In another alternative embodiment, the recessed area  134  and the corresponding drive plate  114  may have any variety of different shapes and sizes. For example, the recessed area  134  and drive plate  114  could have square, triangular, rounded, rhomboid, hexagonal, star-shaped or any other geometric or amorphous, non-symmetric shapes. Additionally, the recessed area  134  and the drive plate  114  can vary in sizes depending on the additional strength required by the drive plate  114  and the size and number of posts  130  needed to support the drive plate  114 . Different sized and shaped drive plates  114  and recessed areas  134  may be appropriate to limit force concentrations on particular points along the recessed area  134 . 
     In another alternative embodiment, the posts  130  and the corresponding post holes  126  may be any variety of size and shape. For example, the posts  130  and post holes  126  may be square, rectangular, triangular, star-shaped, hexagonal, or any other geometric or amorphous, non-symmetric shape. Different sized and shaped posts  130  may be appropriate for different torque requirements and socket cover  14  uses. 
     In another alternative embodiment, the posts  130  extend from the drive plate  114  and the post holes  126  are located in the recessed area  134 . Thus, the drive plate  114  is fitted into the recessed area  134  with the posts  130  extending into the socket cover  14 . Such an embodiment may be used where stronger posts  130  formed of metal or a similarly strong and durable substance are needed to withstand torque forces applied to the drive plate  114 . 
     While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.