Patent Publication Number: US-6666703-B2

Title: Connector for integrated circuits, and assembly for use on integrated circuits

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a connector for detachably mounting an integrated circuit such as a CPU or the like on a circuit board, and an assembly of a heat radiator for radiating the heat of an integrated circuit and a connector for detachably mounting the integrated circuit on a circuit board. 
     2. Description of the Related Art 
     There are known connectors for detachably mounting integrated circuits such as CPUs or the like on circuit boards. FIG. 15 of the accompanying drawings shows one such connector  61  which is surface-mounted on a circuit board  3  and receives a CPU  2  mounted thereon. The connector  61  has an inner case  62  fixed to the circuit board  3  with terminals (not shown) connected thereto by reflow soldering, an outer case  63  covering the inner case  62  and slidable back and forth on the surface of the inner case  62 , a crank rod  64  interposed between the outer case  63  and the inner case  62 , and a lever  65  for turning the crank rod  64  to slide the outer case  63  over the inner case  62 . 
     While the lever  65  is in an upright position, pins  2   c  of the CPU  2  are inserted into respective through holes  66  which are defined in the outer case  63  and the inner case  62 . Then, the lever  65  is tilted forward to turn the crank rod  64 , sliding the outer case  63  forward. The pins  2   c  of the CPU  2  are now connected to an electric circuit (not shown) on the circuit board  3 . 
     The CPU  2  comprises a circuit panel  2   a  with a built-in electronic circuit and a terminal panel  2   b  with the pins  2   c  to which signals from the circuit panel  2   a  are transmitted. When the CPU  2  is energized, the circuit panel  2   a  generates heat and reaches a high temperature. Therefore, a heat radiator (not shown) such as a heat pipe or the like is mounted on the circuit panel  2   a  for cooling the CPU  2 . The heat radiator is attached to the surface of the circuit panel  2   a  by a substance of high heat conductivity such as silicone grease or the like. 
     When attempts are made to remove the heat radiator from the CPU  2  for the purpose of replacing the CPU  2  or the like, the CPU  2  tend to be lifted due to the bonding capability of the silicone grease or the like. If the CPU  2  as it is installed on the connector  61  is lifted, then the pins  2   c  of the CPU  2  and the terminals in the connector  61  are possibly damaged, making it impossible to reuse the CPU  2  and the circuit board  3 . 
     It has been customary to cover the CPU  2  and the heat radiator with a metal box in order to prevent electromagnetic waves generated when the CPU  2  is in operation from being radiated out of the CPU  2 . However, the metal box which houses the CPU  2  and the heat radiator tends to present an obstacle to recent efforts which are being made to reduce the size of the housing of personal computers or the like which incorporate the CPU  2 . 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved connector for an integrated circuit and an improved assembly for use on an integrated circuit. 
     Another object of the present invention is to provide a connector for mounting an integrated circuit having a heat radiator, the connector allowing the heat radiator to be removed without causing damage to the integrated circuit, and an assembly for use on such an integrated circuit. 
     Still another object of the present invention is to provide a connector for an integrated circuit, which is capable of blocking electromagnetic waves from the integrated circuit and which can be reduced in size, and an assembly for use on such an integrated circuit. 
     To achieve the above objects, there is provided according to a first aspect of the present invention a connector for detachably connecting an integrated circuit to a circuit board, the integrated circuit having a rectangular terminal panel and a circuit panel mounted on and projecting upwardly from a surface of the terminal panel, with a heat radiator mounted on the circuit panel, the heat radiator being wider than the circuit panel, electrically conductive, and grounded, the connector comprising an inner case for being fixed to the circuit board, an outer case mounted on the inner case for sliding movement back and forth over the inner case, and a control member pivotally supported by a rear portion of the inner case and angularly movable to slide the outer case back and forth over the inner case, the arrangement being such that the control member is erected, the outer case is slid rearward, and the integrated circuit is placed in the outer case and the inner case, after which the control member is turned down and the outer case is slid forward to connect the integrated circuit and the circuit board to each other, that the control member is brought into abutment against the surface of the terminal panel when the control member is turned down against the integrated circuit, and that the control member is disposed between the heat radiator and the terminal panel when the heat radiator is installed on the circuit panel. 
     With the connector according to the first aspect, the control member is held in abutment against the surface of the terminal panel, and when the heat radiator is installed, the control member is disposed between the heat radiator and the terminal panel. Therefore, the integrated circuit can be removed from the connector while the control member is being held in abutment against the terminal panel. By removing the heat radiator while holding the control member, the force applied to the integrated circuit when the heat radiator is detached is reduced by the control member. The heat radiator can thus be removed without causing damage to the integrated circuit. 
     According to a second aspect of the present invention, there is also provided a connector for detachably connecting an integrated circuit to a circuit board, the integrated circuit having a rectangular terminal panel and a circuit panel mounted on and projecting upwardly from a surface of the terminal panel, the connector comprising an inner case for being fixed to the circuit board, an outer case mounted on the inner case for sliding movement back and forth over the inner case, and a control member pivotally supported by a rear portion of the inner case and angularly movable to slide the outer case back and forth over the inner case, the arrangement being such that the control member is erected, the outer case is slid rearward, and the integrated circuit is placed in the outer case and the inner case, after which the control member is turned down and the outer case is slid forward to connect the integrated circuit and the circuit board to each other, and that the control member is brought into abutment against the surface of the terminal panel and locked by the outer case or the inner case against upward movement when the control member is turned down. 
     With the connector according to the second aspect, when the control member is turned down, the control member is brought into abutment against the surface of the circuit panel. The control member has its rear portion pivotally supported by the inner case and its front portion locked by the inner case or the outer case. Since the integrated circuit is held in the outer case and the inner case by the control member, the heat radiator can be detached from the integrated circuit without causing damage to the integrated circuit. 
     In the connectors according to the first and second aspects, the control member may be superposed on the integrated circuit while the integrated circuit is placed in the outer case and the inner case, the control member may have an opening through which the circuit panel is exposed, and the control member may cover the surface of the terminal panel in its substantial entirety, a front edge of the integrated circuit, and lateral side edges of the integrated circuit. 
     In the connectors according to the first and second aspects, the control member may be superposed on the integrated circuit while the integrated circuit is placed in the outer case and the inner case, and the control member may cover a rear portion of the surface of the terminal panel and rear portions of lateral side edges of the integrated circuit. 
     The control member may have pivot shaft projections serving as pivot shafts and eccentric shaft projections serving as eccentric shafts, the inner case may have pivot shaft supports pivotally supporting the pivot shafts, and the outer case may have eccentric shaft engaging members engaging the eccentric shafts. 
     The pivot shaft projections may have respective bottomed pivot shaft grooves which are open upwardly and pivotally support the pivot shaft projections, and the pivot shaft grooves may have retentive members for preventing the pivot shaft projections from being dislodged upwardly when the pivot shaft projections are supported in the pivot shaft grooves. The retentive members are effective to prevent the control member from being dislodged from the outer case and the inner case when the control member is operated on. 
     The inner case or the outer case should preferably have a keeper for preventing the control member from turning further back when the control member is erected. Inasmuch as the control member is prevented by the keeper from being turned further back, the control member does not damage any electronic circuits and parts which may possibly be disposed behind the connector on the circuit board. 
     In the connector according to the first aspect, the control member should preferably have a locking member for engaging the outer case or the inner case to prevent the control member from moving upwardly when the control member is turned down. With the control member having the locking member, the integrated circuit is firmly held on the connector by the control member. The heat radiator can thus be removed without damaging the integrated circuit. 
     Preferably, the control member has a shield for blocking electromagnetic waves produced by the integrated circuit. Because the shield can block electromagnetic waves produced by the integrated circuit, no electromagnetic waves are emitted out of the connector even when the clock frequency of the integrated circuit is increased. 
     The control member may be coated with an electrically conductive paint, or plated with a metal layer, or may have an electrically conductive tape applied thereto. The control member may include a metal panel or a metal mesh. 
     In the connectors according to the first and second aspects, the control member may comprise a bent metal bar. 
     The control member may have a retracting bent portion and an advancing bent portion which extend from a pivot shaft pivotally supported by the rear portion of the inner case, the retracting bent portion being positioned rearward of the pivot shaft to move the outer case rearward when the control member is erected, the advancing bent portion begin positioned forward of the pivot shaft to move the outer case forward when the control member is turned down. 
     Preferably, the control member extends forward from a substantially central joint of a pivot shaft pivotally supported laterally by the rear portion of the inner case, and has eccentric shafts disposed laterally on opposite sides of the joint and displaced off-center from the pivot shaft. When the eccentric shafts are turned by the control member extending from the joint, uniform forces are applied from the control member to the control member, thus allowing the outer case to move forward uniformly in its lateral direction. Therefore, the integrated circuit is smoothly connected to the circuit board. 
     The bent metal bar is preferably covered with a synthetic resin layer. When the integrated circuit is installed in position, the control member abuts against the surface of the terminal panel. Since the surface of the bent metal bar is covered with a synthetic resin layer, the control member does not damage the terminal panel even when the integrated circuit vibrates. 
     According to a third aspect of the present invention, there is provided a connector for detachably connecting an integrated circuit to a circuit board, the integrated circuit having a rectangular terminal panel and a circuit panel mounted on and projecting upwardly from a surface of the terminal panel, with a heat radiator mounted on the circuit panel, the heat radiator being wider than the circuit panel, electrically conductive, and grounded, the connector comprising an inner case for being fixed to the circuit board, an outer case mounted on the inner case for sliding movement back and forth over the inner case, a control member pivotally supported by a rear portion of the inner case and angularly movable to slide the outer case back and forth over the inner case, and a locking cover for being locked by the inner case or the outer case, the locking cover having an opening through which the circuit panel is exposed, covering the surface of the terminal panel in its substantial entirety and covering the control member, the arrangement being such that the locking cover is disposed between the heat radiator and the terminal panel when the heat radiator is installed on the circuit panel. 
     With the integrated circuit, the outer case, and the inner case being covered with the locking cover, since the control member is covered by the locking cover, the integrated circuit cannot be removed unless the locking cover is detached. When the heat radiator is removed from the integrated circuit, since the integrated circuit is locked by the locking cover, forces applied to the integrated circuit are reduced. The heat radiator can thus be removed with no damage caused to the integrated circuit. 
     The locking cover should preferably have a shield for blocking electromagnetic waves produced by the integrated circuit. As the shield is capable of blocking electromagnetic waves, it is not necessary to use other members to block electromagnetic waves produced by the integrated circuit. Consequently, it is possible to reduce the size of the entire assembly including the circuit board. 
     There is also provided in accordance with a fourth aspect of the present invention an assembly for use on an integrated circuit, comprising a connector for detachably mounting an integrated circuit on a circuit board, the integrated circuit having a rectangular terminal panel and a circuit panel mounted on and projecting upwardly from a surface of the terminal panel, and a heat radiator mounted on the circuit panel, the heat radiator being wider than the circuit panel, electrically conductive, and grounded, the connector comprising an inner case for being fixed to the circuit board, an outer case mounted on the inner case for sliding movement back and forth over the inner case, and a control member pivotally supported by a rear portion of the inner case and angularly movable to slide the outer case back and forth over the inner case, the arrangement being such that the control member is erected, the outer case is slid rearward, and the integrated circuit is placed in the outer case and the inner case, after which the control member is turned down and the outer case is slid forward to connect the integrated circuit and the circuit board to each other, the control member being superposed on the integrated circuit while the integrated circuit is placed in the outer case and the inner case, and having a shield for blocking electromagnetic waves produced by the integrated circuit, the shield and the heat radiator jointly serving to block electromagnetic waves produced by the integrated circuit. 
     As the heat radiator usually used with the integrated grated circuit is electrically conductive and the control member of the connector has the shield, it is possible to block electromagnetic waves generated by the heat radiator and the connector. As a result, other members need to be used to block electromagnetic waves produced by the integrated circuit, making it possible to reduce the size of the entire assembly including the circuit board. 
     Preferably, the shield is electrically connected to the heat radiator and grounded through the heat radiator. Since only the heat radiator is required to be grounded, the shield does not need to be individually grounded. 
     Preferably, the shield has an opening through which the circuit panel is exposed, covers the terminal panel in its substantial entirety, and has a first projection projecting upwardly around the opening, the heat radiator having a second projection projecting downwardly from a surface thereof which faces the shield, the first projection and the second projection jointly surrounding the periphery of the circuit panel in transverse directions thereof when the heat radiator is mounted on the circuit panel. Because the periphery of the circuit panel in transverse directions thereof is surrounded by the first projection and the second projection which are electrically conductive members, electromagnetic waves produced by the integrated circuit are more reliably be prevented from leaking out. 
     There is further provided in accordance with a fifth aspect of the present invention an assembly for use on an integrated circuit, comprising a connector for detachably mounting an integrated circuit on a circuit board, the integrated circuit having a rectangular terminal panel and a circuit panel mounted on and projecting upwardly from a surface of the terminal panel, a heat radiator mounted on the circuit panel, the heat radiator being wider than the circuit panel, electrically conductive, and grounded, the connector comprising an inner case for being fixed to the circuit board, an outer case mounted on the inner case for sliding movement back and forth over the inner case, and a control member pivotally supported by a rear portion of the inner case and angularly movable to slide the outer case back and forth over the inner case, the arrangement being such that the control member is erected, the outer case is slid rearward, and the integrated circuit is placed in the outer case and the inner case, after which the control member is turned down and the outer case is slid forward to connect the integrated circuit and the circuit board to each other, and an electrically conductive locking cover for being locked by the inner case or the outer case, the locking cover having an opening through which the circuit panel is exposed, covering the surface of the terminal panel in its substantial entirety and covering the control member, the locking cover being disposed between the heat radiator and the terminal panel, electrically connected to the heat radiator, and grounded through the heat radiator. 
     The electrically conductive locking cover of the connector is effective to prevent electromagnetic waves produced by the terminal panel from leaking out, and the heat radiator is effective to prevent electromagnetic waves produced by the circuit panel from leaking out. The locking cover and the heat radiator thus prevent electromagnetic waves from the integrated circuit from leaking without the need for other members. 
     The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a connector according to a first embodiment of the present invention; 
     FIG. 2 is an exploded perspective view of the connector according to the first embodiment; 
     FIG.  3 ( a ) is a plan view of a cover of the connector according to the first embodiment; 
     FIG.  3 ( b ) is a cross-sectional view of a cam assembly of the connector according to the first embodiment; 
     FIGS.  4 ( a ) through  4 ( c ) are fragmentary side elevational views showing the manner in which the cam assembly operates; 
     FIGS.  5 ( a ) through  5 ( c ) are side elevational views showing the manner in which a CPU is mounted on the connector according to the first embodiment; 
     FIG.  5 ( d ) is a perspective view of electrically conductive clips for use on the connector according to the first embodiment; 
     FIGS.  6 ( a ) and  6 ( b ) are side elevational views showing the manner in which the connector according to the first embodiment is fixed in position by a fixing device; 
     FIGS.  7 ( a ) through  7 ( c ) are views showing a modification of the connector according to the first embodiment; 
     FIGS.  8 ( a ) and  8 ( b ) are perspective and side elevational views, respectively, of a connector according to a second embodiment of the present invention; 
     FIG.  9 ( a ) is a plan view of a connector according to a third embodiment of the present invention; 
     FIG.  9 ( b ) is a front elevational view of the connector according to the third embodiment; 
     FIGS.  9 ( c ) and  9 ( d ) are plan views of modifications of the connector according to the third embodiment; 
     FIGS.  10 ( a ) and  10 ( b ) are fragmentary cross-sectional views of a cam assembly of the connector according to the third embodiment; 
     FIG. 11 is a side elevational view of the connector according to the third embodiment with a heat radiator mounted thereon; 
     FIG. 12 is a plan view of a modification of the connector according to the third embodiment; 
     FIG. 13 is a perspective view of another modification of the connector according to the third embodiment; 
     FIG. 14 is a perspective view of a connector according to a fourth embodiment of the present invention; and 
     FIG. 15 is a perspective view of a conventional connector. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A connector according to a first embodiment of the present invention will first be described below with reference to FIGS.  1  through  6 ( a ),  6 ( b ). As shown in FIG. 1, a connector  1  according to a first embodiment of the present invention serves as a CPU socket for detachably mounting a CPU (integrated circuit)  2  and is surface-mounted on a circuit board  3 . The CPU  2  comprises a circuit panel  2   a  with a built-in electronic circuit, a terminal panel  2   b  extending around peripheral edges of the circuit panel  2   a,  and a plurality of pins  2   c  (see FIG.  5 ( a )) projecting downwardly from the terminal panel  2   b.    
     The connector  1  has an inner case  4  fixed to the circuit board  3  with terminals (not shown) connected thereto by reflow soldering, an outer case  5  covering the surface of the inner case  4  and slidable back and forth on the surface of the inner case  4 , and a cover  6  mounted on the inner case  4  and the outer case  5  for fully covering the CPU  2 . In the present embodiment, the cover  6  doubles as a control member for sliding the outer case  5  back and forth on the inner case  4 . 
     As shown in FIG. 2, the inner case  4  has a plurality of through holes  7  defined therein for insertion of the pins  2   c  therethrough. Terminals (not shown) are mounted respectively in the through holes  7  for connecting the pins  2   c  to an electric circuit (not shown) on the circuit board  3 . The inner case  4  has three spaced pivot shaft supports  8  projecting rearward from a rear edge thereof for supporting a rear portion of the cover  6 . The pivot shaft supports  8  have bottomed grooves  9  which are open upwardly. Locking steps  10  are disposed in the grooves  9  in those pivot shaft supports  8  which are positioned on left and right ends of the inner case  4 . The locking steps  10  serve to engage respective retentive teeth  25  of the cover  6 . As shown in FIG.  3 ( b ), the locking steps  10  are shallower than the bottoms of the grooves  9  in the transverse direction of the inner case  4 . 
     The inner case  4  has guide ridges  11 , two on each side thereof, which slidably engage in respectively guide slots  17  defined in the outer case  5 . The inner case  4  also has a tooth  12  on its front end for engaging in a locking slot  20  defined in the front end of the cover  6 . The pivot shaft supports  8  have a cover keeper  13  on their rear ends for preventing the cover  6  from turning further back from an erected position as shown in FIG.  4 ( a ). 
     As shown in FIG. 2, the outer case  5  has a plurality of through holes  14  defined therein for insertion of the pins  2   c  therethrough. The outer case  5  has left and right side walls  5   a  extending downwardly from respective left and right side edges thereof for covering the left and right side edges of the inner case  4 . The outer case  5  also has eccentric shaft engaging members  15  projecting rearward from a rear edge thereof and disposed between the pivot shaft supports  8  of the inner case  4 . The eccentric shaft engaging members  15  have bottomed grooves  16  which are open downwardly. Eccentric shaft projections  24  on the cover  6  engage respectively in the grooves  16 . The guide slots  17  are defined in the left and right side walls  5   a  of the outer case  5  for being guided back and forth by the guide ridges  11  of the inner case  4 . 
     As shown in FIG. 2, the cover  6  comprises an upper panel  6   a  covering the upper surface of the outer case  5 , left and right side walls  6   b  covering the left and right side edges of the outer case  5 , a front wall  6   c  covering the front edges of the outer case  5  and the inner case  4 , and a cam assembly  18  disposed on the rear end of the cover  6 . The front wall  6   c  has a tab  19  projecting forward from its front surface and a locking slot  20  defined in its inner surface for receiving the tooth  12  on the inner case  4 . The upper panel  6   a  has a circuit opening  21  defined centrally therein for exposing the circuit panel  2   a  of the CPU  2  when the cover  6  is closed over the CPU  2 . In the present embodiment, the surfaces of the upper panel  6   a,  the left and right side walls  6   b,  and the front wall  6   c  of the cover  6  are covered with a plated metal layer, providing a shield  22 . 
     As shown in FIG.  3 ( a ), the cam assembly  18  comprises six cams projecting rearward (downward in FIG.  3 ( a )) from the upper panel  6   a.  The cam assembly  18  has pivot shafts  23   a  and eccentric shafts  24   a.  The four inner cams of the cam assembly  18  are disposed between the pivot shaft supports  8  of the inner case  4  and the eccentric shaft engaging members  15  of the outer case  5 , and the left and right outer cams of the cam assembly  18  are disposed on outer sides of the pivot shaft supports  8  of the inner case  4 . 
     The cam assembly  18  has pivot shaft projections  23  making up the pivot shafts  23   a  and supported by the pivot shaft supports  8  of the inner case  4  and eccentric shaft projections  24  making up the eccentric shafts  24   a  and engaged by the eccentric shaft engaging members  15  of the outer case  5 . The eccentric shaft projections  24  are displaced off-center upwardly from the pivot shaft projections  23  in FIG.  3 ( a ). Those pivot shaft projections  23  which are mounted on the left and right side walls  6   b  of the cover  6  serve as retentive teeth  25  having downwardly inclined surfaces  25   a  as shown in FIGS.  3 ( a ) and  3 ( b ). 
     The inner case  4 , the outer case  5 , and the cover  6  are assembled together as follows: The pivot shaft projections  23  of the cam assembly  18  are inserted into the grooves  9  defined in the pivot shaft supports  8 . As described above, the locking steps  10  are disposed in the grooves  9  in those pivot shaft supports  8  which are positioned on left and right ends of the inner case  4 , and shallower than the bottoms of the grooves  9  in the transverse direction of the inner case  4 , and those pivot shaft projections  23  which are mounted on the left and right side walls  6   b  serve as retentive teeth  25  with the inclined surfaces  25   a.  Therefore, the pivot shaft projections  23  move downwardly (FIGS.  3 ( a ) and  3 ( b )) as the inclined surfaces  25   a  are pushed outwardly by the locking steps  10 , until finally the retentive teeth  25  are brought into the grooves  9  below the locking steps  10 . Once the retentive teeth  25  are placed in the grooves  9  below the locking steps  10 , the cover  6  cannot be removed from the inner case  4  as the retentive teeth  25  are engaged by the locking steps  10 . 
     Then, the outer case  5  is mounted on the surface of the inner case  4 . At this time, the outer case  5  is positionally adjusted to bring the eccentric shaft projections  24  of the cam assembly  18  into the grooves  16  in the eccentric shaft engaging members  15  of the outer case  15 , and to bring the guide ridges  11  on the side edges of the inner case  4  into the guide slots  17  defined in the inner surfaces of the side walls  5   a  of the outer case  5 . Since the outer case  5  is held in engagement with the inner case  4  through the engagement of the guide ridges  11  in the guide slots  17 , the outer case  5  is prevented from disengaging from the inner case  4 . Then, a metal clip  26  for electric connection to a heat radiator  27  (described later on) is mounted on an edge of the circuit opening  21  of the cover  6 . The connector  1  thus assembled is then surface-mounted on the circuit board  3  in a reflow furnace (not shown). 
     The CPU  2  is then installed on the circuit board  3  with the connector  1  mounted thereon from above the outer case  5 . At this time, as shown in FIGS.  4 ( a ) and  5 ( a ), the cover  6  is erected substantially perpendicularly to the circuit board  3 . The pins  2   c  of the CPU  2  are inserted into the through holes  14  in the outer case  5  and the through holes  7  in the inner case  4 . At present, the pins  2   c  are not electrically connected to the terminals in the through holes  7  in the inner case  4 . Then, the cover  6  is angularly moved forward about the pivot shaft projections  23  of the cam assembly  18 . 
     As shown in FIGS.  4 ( a ) through  4 ( c ), the eccentric shaft projections  24  move forward, pushing the eccentric shaft engaging members  15  forward. When the cover  6  is fully turned down into overlapping relation to the CPU  2 , as shown in FIGS.  4 ( c ) and  5 ( c ), the outer case  5  is moved forward by the eccentric shaft projections  24 , causing the pins  2   c  of the CPU  2  to be electrically connected to the terminals in the through holes  7  in the inner case  4 . When the CPU  2  is thus mounted on the connector  1 , therefore, the terminal panel  2   b  of the CPU  2  is covered by the cover  6 . 
     In the present embodiment, since the retentive teeth  25  of the cover  6  are prevented from moving upwardly by the locking steps  10 , the cover  6  can smoothly be turned down without the cam assembly  18  moving upwardly. When the cover  6  is erected substantially perpendicularly to the inner case  4 , the rear end of the cam assembly  18  abuts against the cover keeper  13  on the rear ends of the pivot shaft supports  8 , as shown in FIG.  4 ( a ). Since the cover  6  is prevented from being further turned rearward, the cover  6  does not damage any electronic circuits and parts which may possibly be disposed behind the connector  1 . 
     Then, as shown in FIG.  6 ( a ), a heat radiator  27  is mounted on the circuit panel  2   a  of the CPU  2  mounted on the connector  1 . Specifically, the surface of the circuit panel  2   a  is coated with a silicone grease  28 . Then, the heat radiator  27  is mounted on the circuit panel  2   a  from above the surface of the silicone grease  28 . The silicone grease  28  has a relatively large bonding capability, making it difficult for the heat radiator  27  to be detached from the CPU  2 . The silicone grease  28  also has a property to transfer heat easily. 
     The heat radiator  27  is made of aluminum alloy and has an area wider than the circuit panel  2   a  of the CPU  2  and the circuit opening  21  in the cover  6 . When the heat radiator  27  is mounted on the CPU  2 , the heat radiator  27  is overlaps the surface of the upper panel  6   a  of the cover  6 . The shield  22  of the cover  6  and the heat radiator  27  are electrically connected to each other by the clip  26  which is mounted on the edge of the circuit opening  21  of the cover  6 . 
     The heat radiator  27  is fixed to the circuit board  3  by a fixing device  29  shown in FIG.  6 ( b ). The fixing device  29  comprises a rear plate  30  disposed on the reverse side of the circuit board  3 , a fixing plate  31  disposed above the heat radiator  27  and pressing the heat radiator  27  toward the circuit board  3 , and joints  32  joining the rear plate  30  and the fixing plate  31  to each other these components of the fixing device  29  are electrically conductive, and grounded with the rear plate  30  being connected to a grounding circuit (not shown). 
     The surface of the cover  6  is covered with a plated metal layer, providing the shield  22 , and the metal clip  26  is mounted on the cover  6 . The heat radiator  27  and the shield  22  are electrically connected to each other by the clip  26 . The shield  22  is thus connected to the grounding circuit by the clip  26 , the heat radiator  27 , and the fixing device  29 . Therefore, electromagnetic waves that are radiated when the CPU  2  is energized are blocked by the cover  6  covered with the shield  22  and the electrically conductive heat radiator  27 . 
     Since the heat radiator  27  is positioned above the surface of the cover  6 , the cover  6  can be removed for replacement of the CPU  2  only after the heat radiator  27  is detached. When the heat radiator  27  is removed, the CPU  2  remains held in the outer case  5  and the inner case  4  by the cover  6 . Consequently, when the heat radiator  27  is removed from the CPU  2 , the CPU  2  is prevented from being detached from the connector  1  and the pins  2   c,  etc. of the CPU  2  are prevented from being damaged. 
     After the heat radiator  27  is removed from the CPU  2 , the tab  19  of the cover  19  is lifted to erect the cover  6  as shown in FIG.  5 ( b ). The outer case  5  slides rearward, disconnecting the pins  2   c  of the CPU  2  from the terminals in the inner case  4 . Then, the CPU  2  is lifted off the connector  1 . 
     The clip  26  may have a lance  26   a  as shown in a left-hand side of FIG.  5 ( d ), or may have a bent portion  26   b  as shown in a right-hand side of FIG.  5 ( d ). In the present embodiment, the heat radiator  27  is bonded to the circuit panel  2   a  of the CPU  2  by the silicone grease  28 . However, the heat radiator  27  may be secured position by any of various known means. 
     An assembly for use on an integrated circuit, which has a connector  1   a  according to a modification of the first embodiment, will be described below. In this modification, as shown in FIGS.  7 ( a ) and  7 ( c ), the heat radiator  27  has a first annular projection (first projection)  33  projecting downwardly from a lower surface thereof. As shown in FIGS.  7 ( b ) and  7 ( c ), the cover  6  has a second annular projection (second projection)  34  projecting upwardly from an upper surface thereof in surrounding relation to the first annular projection  33  inserted therein. 
     According to the present modification, the cover  6  is molded of an electrically conductive synthetic resin which comprises a synthetic resin and a carbon or metal powder mixed therewith. The electrically conductive synthetic resin is melted and injection-molded into the cover  6  with the carbon or metal powder localized on its surface to turn the surface into an electrically conductive shield. Other structural details of the modified connector  1   a  are identical to the connector according to the first embodiment, and will not be described in detail below. 
     For installing the CPU  2  on the connector  1   a,  the CPU  2  is placed in the inner case  4  and the outer case  5 , and then the cover  6  is turned down to cover the CPU  2 , after which the heat radiator  27  is mounted on the cover  6  above the CPU  2 . At this time, as shown in FIG.  7 ( c ), the first annular projection  33  on the heat radiator  27  is inserted in the second annular projection  34  on the cover  6 , whereupon side edges of the circuit panel  2   a  of the CPU  2  are closed by the first annular projection  33  and the second annular projection  34 . Therefore, electromagnetic waves emitted from the CPU  2  are blocked against radiation from the assembly by the first annular projection  33  and the second annular projection  34 . 
     In the modification illustrated in FIGS.  7 ( a ) through  7 ( c ), each of the first and second projections  33 ,  34  is of an annular shape. However, each of the first and second projections may be of a C shape, and the first and second projections may be combined with each other so as to surround the periphery of the circuit panel  2   a  in its transverse directions. Although the first and second projections  33 ,  34  are provided one each in the illustrated modification, a plurality of first projections and a plurality of second projections may be employed. 
     An assembly for use on an integrated circuit, which has a connector  1   b  according to a second embodiment of the present invention, will be described below with reference to FIGS.  8 ( a ) and  8 ( b ). As shown in FIG.  8 ( a ), the connector  1   b  according to the second embodiment has a cover  6  for covering a substantially rear half of the terminal panel  2   b  of the CPU  2 . The cover  6  comprises a metal panel (not shown) serving as a shield and covered with a layer of synthetic resin formed by insert molding. A metal tip  35  is fastened to the upper surface of the cover  6  by a self-tapping screw  36  which is threaded into the metal panel of the cover  6 . Therefore, the tip  35  and the metal panel of the cover  6  are electrically connected to each other. 
     As shown in FIGS.  8 ( a ) and  8 ( b ), the heat radiator  27  according to the second embodiment has a projection or land  37  projecting downwardly which has an edge that is complementary in shape to the front edge of the cover  6 . Other structural details of the connector  1   b  according to the second embodiment are identical to the connector according to the first embodiment, and will not be described in detail below. 
     For installing the CPU  2  on the connector  1   b,  the CPU  2  is placed in the inner case  4  and the outer case  5 , and then the cover  6  is turned down into contact with the surface of the CPU  2 . The rear portion of the terminal panel  2   b  is covered by the cover  6 . 
     The surface of the circuit panel  2   a  is coated with a silicone grease  28 , and then the heat radiator  27  is installed. As shown in FIG.  8 ( b ), the heat radiator  27  is now mounted on the circuit panel  2   a.  Since the downward projection  37  is disposed on the reverse side of the heat radiator  27 , the side edges of the circuit  2   a  are surrounded by the projection  37  and the cover  6 . The heat radiator  27  is electrically connected to the cover  6  by the tip  35 . The heat radiator  27  is also connected to a grounding circuit, as with the previous embodiment. Therefore, electromagnetic waves emitted from the CPU  2  are blocked against radiation from the assembly by the projection  37  and the cover  6 . 
     In the second embodiment, the cover  6  employs the metal panel as the shield. However, the cover  6  may employ a metal mesh (not shown) as the shield. Since such a metal mesh is capable of blocking electromagnetic waves, no electromagnetic waves are emitted from the cover  6 . 
     An assembly for use on an integrated circuit, which has a connector  1   c  according to a third embodiment of the present invention, will be described below with reference to FIGS.  9 ( a ) through  11 . As shown in FIGS.  9 ( a ) and  9 ( b ), the connector  1   c  according to the third embodiment has a control member for sliding the outer case  5  back and forth in the form of a lever  38  bent from a metal bar. 
     The lever  38  has a cam assembly  39  on its rear end and a locking member  40  on its front end for engaging the tooth  12  of the inner case  4 . The lever  38  comprises a metal bar covered with a synthetic resin layer. The synthetic resin layer is formed by placing a heat-shrinkable synthetic resin pipe over the metal bar and then heating the heat-shrinkable synthetic resin pipe. As shown in FIGS.  9 ( a ) and  9 ( b ), the lever  38  is shaped such that it contacts the surface of the terminal panel  2   b  when the lever  38  is turned down forward onto the CPU  2 . As shown in FIG. 11, the lever  38  has support protrusions  41  disposed near front and rear ends of the portions thereof which contact the terminal panel  2   b,  the support protrusions  41  contacting the reverse surface of the heat radiator  27  when the heat radiator  27  is mounted on the CPU  2 . 
     As shown in FIGS.  10 ( a ) and  10 ( b ), the cam assembly  39  of the lever  38  has pivot shafts  42  supported by the inner case  4 . As shown in FIG.  10 ( b ), the cam assembly  39  also has an advancing bent portion  43  which is bent obliquely forward of each of the pivot shafts  42  when the lever  38  is turned down, and a retracting bent portion  44  which extends upwardly from the advancing bent portion  43  and is bent forward when the lever  38  is turned down. In FIG.  10 ( a ), the cam assembly  39  also has a lever keeper  45  extending upwardly and bent to the right from the retracting bent portion  44  for engaging a third abutment surface  48  of the outer case  5  to prevent the lever  38  from turning further back from an erected position of the lever  38  in which the lever  38  is substantially perpendicular to the outer case  5 . 
     As shown in FIGS.  10 ( a ) and  10 ( b ), the outer case  5  has in its rear portion a first abutment surface  46  for abutting against the advancing bent portion  43  of the lever  38 , a second abutment surface  47  for abutting against the retracting bent portion  44  of the lever  38 , and a third abutment surface  48  for abutting against the lever keeper  45  of the lever  38 . Other structural details of the connector  1   c  according to the third embodiment are identical to the connector according to the first embodiment, and will not be described in detail below. 
     For installing the CPU  2  on the connector  1   c,  the lever  38  is erected substantially perpendicularly to the circuit board  3 . At this time, since the pivot shafts  42  of the lever  38  are supported by the case  4 , as shown in FIG.  10 ( a )), the lever  38  is turned about the pivot shafts  42 . The lever  38  is turned while the retracting bent portion  44  is pushing the second abutment surface  47  rearward (to the right in FIG.  10 ( a )). Then, the CPU  2  is placed in the inner case  4  and the outer case  5 . When the lever  38  is turned down forward from the erected position, the lever  38  is turned forward about the pivot shafts  42 . 
     At this time, as shown in FIG.  10 ( b ), the lever  38  is turned while the advancing bent portion  43  is pushing the first abutment surface  46  forward (to the left in FIG.  10 ( b )). The outer case  5  is slid forward, causing the pins  2   c  of the CPU  2  to be electrically connected to the terminals in the through holes  7  in the inner case  4 . As shown in FIGS.  9 ( a ) and  9 ( b ), the locking member  40  on the front end of the lever  38  engages the tooth  12  on the front end of the inner case  4 . The CPU  2  is now secured to the connector  1   c  by the lever  38 . 
     Then, as shown in FIG. 11, the heat radiator  27  is mounted on the circuit panel  2   a  of the CPU  2  mounted on the connector  1   c,  with the silicone grease  28  interposed between the heat radiator  27  and the circuit panel  2   a.  At this time, the reverse side of the heat radiator  27  is held in abutment against the support protrusions  41  of the lever  38 . The heat radiator  27  is held down by the fixing plate  31  of the fixing device  29 , pressing the CPU  2  against the connector  1   c  with the support protrusions  41 . 
     In the third embodiment, since the lever  38  is held against the surface of the terminal panel  2   b,  the CPU  2  is held on the connector  1   c  even when the heat radiator  27  is removed. Consequently, when the heat radiator  27  is removed from the CPU  2 , the CPU  2  is prevented from being detached from the connector  1   c  and the pins  2   c,  etc. of the CPU  2  are prevented from being damaged. Inasmuch as the metal bar of the lever  38  is covered with the synthetic resin, the surface of the terminal panel  2   b  is not worn even when the lever  28  held in contact with the terminal panel  2   b  vibrates. 
     After the heat radiator  27  is removed from the CPU  2 , the locking member  40  of the lever  38  is disengaged from the tooth  12  of the inner case  4  and lifted to erect the lever  38 . The outer case  5  is slid rearward, disconnecting the pins  2   c  of the CPU  2  from the terminals in the inner case  4 . The CPU  2  can then easily be detached from the connector  1   c  when the CPU  2  is lifted. 
     In the third embodiment, the lever  38  is not limited to the shape shown in FIGS.  9 ( a ) and  9 ( b ), but may be shaped as shown in FIGS.  9 ( c ) and  9 ( d ). Specifically, in FIG.  9 ( c ), a connector  1   c ′ has a lever  38  including a cam assembly  39  of a conventional crank structure and extending straight downwardly from the cam assembly  39  in FIG.  9 ( c ). In FIG.  9 ( d ), a connector  1   c ″ has a lever  38  bent to extend on one side of the circuit panel  2   a  out of interference therewith. The lever  38  thus bent is advantageous in that if the heat radiator  27  comprises a heat pipe, the lever  38  is kept out of interference with pipes and cables connected to the heat radiator  27 . 
     A connector  1   d  according to a modification of the third embodiment will be described below with reference to FIG.  12 . As shown in FIG. 12, the connector  1   d  has a lever  38  including a cam assembly in the form of a crank rod  50  extending transversely in rear portions of the outer case  5  and the inner case  4 . The crank rod  50  has two pivot shafts  51  supported by the inner case  4  and two eccentric shafts  52  displaced off-center from the pivot shafts  51 . The eccentric shafts  52  are displaced off-center forward from the pivot shafts  51  when the lever  38  is turned down forward, and engage the outer case  5 . 
     The lever  38  extends from an intermediate portion of the crank rod  50  between the eccentric shafts  52  and is bent out of interference with the circuit panel  2   a  of the CPU  2 . According to the present modification, the lever  38  comprises a metal bar covered with a layer of synthetic resin formed by insert molding. The lever  38  does not have a locking member on its front end for engaging a tooth of the inner case  4 . Other structural details of the connector  1   c  according to the present modification are identical to the connector according to the third embodiment, and will not be described in detail below. 
     For installing the CPU  2  on the connector  1   d,  the CPU  2  is placed in the inner case  4  and the outer case  5 , and then the lever  38  is turned down forward. Since the lever  38  extends from the intermediate portion of the crank rod  50  between the eccentric shafts  52 , the force applied to the lever  38  is imposed uniformly on the eccentric shafts  52 . Therefore, the outer case  5  is slid smoothly forward. 
     According to the present modification, as shown in FIG. 12, the lever  38  is bent out of interference with the circuit panel  2   a  of the CPU  2 , and hence abuts against the surface of the circuit panel  2   a.  Then, the heat radiator  27  is mounted in place from above the CPU  2 . Since the heat radiator  27  projects laterally beyond the circuit panel  2   a,  the lever  28  is disposed between the heat radiator  27  and the terminal panel  2   b  of the CPU  2 . Therefore, the heat radiator  27  can be removed from the CPU  2  while the lever  38  is being held in abutment against the terminal panel  2   b.    
     The force applied to the CPU  2  at this time can be reduced by removing the CPU  2  while holding the lever  38 . 
     A connector  1   e  according to a second modification of the third embodiment will be described below with reference to FIG.  13 . As shown in FIG. 13, the connector  1   e  has a lever  38  whose length is selected such that its distal front end is positioned behind the circuit panel  2   a  when the CPU  2  is mounted in place. The lever  28  has a cam assembly  39  on its rear end, which, as shown in FIG. 13, projects rearward as a bifurcated structure and has pivot shaft projections  23  projecting inwardly toward each other and eccentric shaft projections  24  projecting outwardly away from each other. The pivot shaft projections  23  are supported by pivot shaft supports (not shown) of the inner case  4 , and the eccentric shaft projections  24  are supported by eccentric shaft engaging members (not shown) of the outer case  5 . 
     For installing the CPU  2  on the connector  1   e,  the CPU  2  is placed in the inner case  4  and the outer case  5 , and then the lever  38  is turned down forward. Since the lever  38  lies behind the circuit panel  2   a,  the lever  38  is held in abutment against the surface of the terminal panel  2   b.  Then, the heat radiator  27  is mounted in place from above the CPU  2 , and the lever  38  is disposed between the heat radiator  27  and the terminal panel  2   b.  The heat radiator  27  can be removed from the CPU  2  while the lever  38  is being held in abutment against the terminal panel  2   b.  The force applied to the CPU  2  at this time can be reduced by removing the CPU  2  while holding the lever  38 . 
     A connector  1   f  according to a fourth embodiment of the present invention will be described below with reference to FIG.  14 . As shown in FIG. 14, the connector  1   f  has a control member for sliding the outer case  5  back and forth on the inner case  4 , in the form of a lever  38  which is produced by bending a metal bar. Specifically, the lever  38  has a crank rod  50  disposed in the rear portions of the outer case  5  and the inner case  4  and including pivot shafts  51  supported by the inner case  4  and eccentric shafts  52  displaced off-center from the pivot shafts  51 . The lever  38  projects outwardly from side edges of the outer case  5  and the inner case  4 , and is bent perpendicularly to the pivot shafts  51 . 
     In the fourth embodiment, the connector  1   f  includes a locking cover  53  which covers the CPU  2  and the connector  1   f  after the CPU  2  is installed on the connector  1   f.  The locking cover  53  comprises a metal panel serving as a shield and a synthetic resin layer covering the metal panel, and has connectors  54  disposed on its surface through which the metal panel of the locking cover  53  is exposed. The locking cover  53  is of such a size as to cover the lever  38  which has been turned down forward, from above. The locking cover  53  is locked by teeth (not shown) on side walls of the outer case  5 . 
     The locking cover  53  has a circuit opening  21  defined centrally therein for exposing the circuit panel  2   a  of the CPU  2  when the upper surface of the CPU  2  is covered with the locking cover  53 . Other structural details of the connector  1   f  according to the fourth embodiment are identical to the connector according to the other embodiments, and will not be described in detail below. 
     In the fourth embodiment, as with the conventional connector, the lever  38  is erected to slide the outer case  5  rearward, and then the CPU  2  is installed from above the outer case  5  and the inner case  4 . The lever  38  is turned down forward to slide the outer case  5  forward, electrically connecting the CPU  2  to the electric circuit on the circuit board  3 . Then, the locking cover  53  is installed from above the CPU  2 . At this time, the lever  38  is accommodated in the locking cover  53 . 
     Then, the heat radiator  27  is mounted on the CPU  2 . The heat radiator  27  projects laterally beyond the circuit panel  2   a,  so that the heat radiator  27  is positioned over the locking cover  53 . Since the reverse surface of the heat radiator  27  is held in abutment against the connectors  54 , the heat radiator  27  and the locking cover  53  are electrically connected to each other. As with the previous embodiments, the heat radiator  27 , the CPU  2 , and the connector  1   f  are secured to the circuit board  3  by the fixing device  29 . 
     With the connector  1   f  according to the fourth embodiment, the locking cover  53  includes the metal panel which is connected to the electrically conductive heat radiator  27  by the connectors  54 . The heat radiator  27  is connected to the grounding circuit by the fixing device  29 . Therefore, electromagnetic waves that are radiated when the CPU  2  is energized are blocked by the locking cover  53  and the heat radiator  27 . 
     As the heat radiator  27  is positioned upwardly of the surface of the locking cover  53 , the locking cover  53  can be removed for replacement of the CPU  2  only after the heat radiator  27  is detached. When the heat radiator  27  is removed, the CPU  2  remains held in the outer case  5  and the inner case  4  by the engaging cover  6 . Consequently, when the heat radiator  27  is removed from the CPU  2 , the CPU  2  is prevented from being detached from the connector  1   f  and the pins  2   c,  etc. of the CPU  2  are prevented from being damaged. 
     Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.