Abstract:
An apparatus for making an electrical connection with an electrical unit which has an edge portion and terminals disposed along the edge portion. The apparatus includes a supporting member and a connector supported by the supporting member. The connector has a body elongated in a longitudinal direction and second terminals disposed along the longitudinal direction. The connector slidably guides the edge portion of the electrical unit along the longitudinal direction to a first fully inserted position such that each one of the terminals of the connector faces respective one of the terminals of the electrical unit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an apparatus for electrically connecting electronic units together, and in particular, to an apparatus for electrically connecting electronic units together via a connector supported by a supporting member such as a circuit board. 
   2. Description of the Prior Art 
   In the following description, an electronic circuit package or an electronic unit means a plurality of electronic parts integrated together. The electronic circuit package or electronic unit includes, for example, a circuit board on which an LSI is mounted, a circuit board on which a connector is mounted, a hard disk unit, and a CPU package. 
   In the following description, a connector means a device that electrically connects electronic parts. Either a portion having a female terminal or a portion having a male terminal is a connector. Accordingly, a group of terminals provided at an edge of a circuit board is also a connector as in the case of a terminal  65  in  FIG. 7 . 
   In the following description, a housing means a device that accommodates or supports electronic units. For example, a case, a cabinet, a rack, a chassis, and a frame are housings. 
   In a first conventional technique for an apparatus of this kind, a back board  72  has a connector  73 , and a plurality of electronic circuit packages  71  are connected to the back board  72  via a connector  74 , as shown in  FIG. 9 . Each of the electronic circuit packages  71  has a circuit board and electronic parts such as LSIs  75  which are mounted on the circuit board. A wiring pattern  77  of the electronic circuit package  71  connects the electronic parts such as the LSIs  75  and the connector  74  together. The connector  74  is connected to a connector  73  to electrically connect the electronic circuit package  71  to another electronic circuit package via a wiring pattern  76  in the back board  72 . 
   In this structure, as shown in  FIG. 10 , an electronic circuit package  81  is inserted into a connector  82  in its longitudinal direction, that is, perpendicularly to the direction in which terminals  83  of the connector  82  are arranged so that a terminal of the electronic circuit package  81  is connected to the terminal  83  of the connector  82 . 
   Japanese Patent Laid-Open No. 09-172240 discloses a variation of the above first conventional technique. In this variation, packages are connected to the respective surfaces of the back board. Specifically,  FIG. 1  of Japanese Patent Laid-Open No. 09-172240 shows a device that electrically connects a group of first packages composed of 16 first packages to a group of second packages composed of 16 second packages, via an adapter  30  having 16 connectors  33  arranged on each of its front and back surfaces. The adapter  30  and the connector  33  correspond to the back board  72  and connector  73 , shown in  FIG. 9  of this application. 
   If the apparatus according to the first conventional technique shown in  FIG. 9  is mounted in a housing, it is arranged so that the back board  72  is substantially perpendicular to the top or bottom surface of the housing. Then, the electronic circuit package  71  is inserted into the housing through an opening formed in the front surface of the housing. Subsequently, the connector  74  of the electronic circuit package  71  is connected to the connector  73  of the back board  72 . 
   U.S. Pat. No. 6,128,196 discloses a second conventional technique for an apparatus for electrically connecting electronic units together. With reference to  FIGS. 2 and 9  of U.S. Pat. No. 6,128,196, a circuit board  102  is inserted into a connector  152  of a motherboard  149  from a direction perpendicular to the longitudinal direction of the connector  152 . The motherboard  149  is arranged in a chassis  104  so that the motherboard  149  is parallel to the top surface (or bottom surface) of the chassis  104 . 
   However, the above first conventional technique has the following problems. 
   A first problem is a decrease in cooling efficiency. If a cooling airflow- is allowed to flow parallel to the inserting direction of the electronic circuit package  71 , the back board  72  interrupts the airflow. If the size of the back board is reduced to allow the airflow to flow without being interrupted by the back board  72 , the size of the connector is also reduced. This in turn reduces the number of signal lines and an amount of a current supply. On the other hand, if the cooling airflow is allowed to flow in a direction parallel to the back board  72 , that is, in the vertical direction of  FIG. 9 , no other devices can be mounted above or below this electronic equipment. 
   With the second conventional technique, the motherboard  149  is arranged in the chassis  104  so as to be parallel to the top surface (or bottom surface) of the chassis  104 . Accordingly, the cooling airflow is parallel to the motherboard  149 . Thus, the second conventional technique can solve the above problems of the first conventional technique. However, with the second conventional technique, the circuit board  102  is moved up and down to connect and separate the circuit board  102  to and from the motherboard connector  152 , respectively. Thus, it is difficult to connect and separate the circuit board  102  to and from the motherboard connector  152  unless there is a sufficient clearance between the circuit board  102  and the top surface  124  of the chassis  104 . This problem is particularly severe when the size of the chassis  104  is reduced. 
   According to U.S. Pat. No. 6,128,196, a 1⅜-inch clearance is required on an average to connect and separate the circuit board connector  102  to and from the motherboard connector  152 . With reference to  FIG. 3  of U.S. Pat. No. 6,128,196, the circuit board  102  is accommodated in a framework  159 . The framework  159  has a pivot  210 . The circuit board  102  can be moved up or down by 1⅜ inches or more by engaging the pivot  210  with a receiving block  220 . 
   However, since the size of the chassis  104  is reduced, it is difficult to connect and separate the circuit board  102  to and from the motherboard  149  when the clearance between the circuit board  102  and the top surface  124  of the chassis  104  is less than 1⅜ inches. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to improve cooling efficiency without reducing the number of terminals or signal lines of an electronic circuit package. It is another object of the present invention to enable an electronic circuit package and a connector in a housing to be connected together and separated from each other even if there is only a small clearance between the electronic circuit package and a housing. 
   The inventor has discovered that these objects are accomplished by allowing the electronic circuit package and the connector to be connected together and separated from each other by moving the electronic circuit package in a longitudinal direction of the connector. 
   An apparatus according to the present invention is adapted to make an electrical connection with a first electronic unit having a first edge portion and first terminals disposed along said first edge portion. The apparatus includes a first supporting member and a first connector supported by the first supporting member. The first connector has a body elongated in a longitudinal direction and second terminals disposed along the longitudinal direction. The first connector is adapted to slidably guide the first edge portion of the first electronic unit along the longitudinal direction to a first fully inserted position such that each one of the first terminals faces respective one of the second terminals. According to the present invention, as shown in  FIG. 4 , an electronic circuit package  31  is mounted horizontally in an electronic circuit package  32  constituting a support member. A cooling airflow for cooling electronic parts such as LSIs mounted on the electronic circuit package  31  is allowed to flow parallel to a direction in which the electronic circuit package  31  is inserted. Then, the electronic circuit package  32  does not interrupt the cooling airflow. Thus, the cooling efficiency is improved. The high cooling efficiency is obtained without reducing the size of a ZIF connector  33 . Consequently, the numbers of terminals and signal lines of an electronic circuit package  11  do not decrease. 
   According to the present invention, the electronic circuit package  11  is moved along a longitudinal direction of the ZIF connector  33  to connect the electronic circuit package  11  and the ZIF connector  33 . Thus, the electronic circuit package  11  and the ZIF connector  33  can be connected together and separated from each other even if there is substantially no clearance between the electronic circuit package  11  and a housing  100 . 
   Moreover, in the arrangement shown in  FIG. 1 , the electronic circuit package  11  is connected to both electronic circuit packages  12  and  13 . It is thus possible to double the number of terminals of the electronic circuit package  11 . This increases the upper limit on the number of parts that can be mounted on the electronic circuit package  11 . As a result, the number of electronic circuit packages  11  can be reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This above-mentioned and other objects, features and advantages of this invention will became more apparent by reference to the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a perspective view showing a first embodiment; 
       FIG. 2  is a perspective view showing a first embodiment; 
       FIG. 3  is a perspective view showing a second embodiment; 
       FIG. 4  is a perspective view showing a third embodiment; 
       FIG. 5  is a perspective view showing a forth embodiment; 
       FIG. 6  is a perspective view showing a fifth embodiment; 
       FIG. 7  is a perspective view showing a connector, in an open state, for embodying the first to fifth embodiments; 
       FIG. 7   a  is a perspective view showing the connector of  FIG. 7  in a closed state: 
       FIG. 8  is a perspective view showing a second connector, in an open state, for embodying the first to fifth embodiments; 
       FIG. 8   a  is a perspective view showing the connector of  FIG. 8  in a closed state; 
       FIG. 9  is a perspective view showing a configuration in the prior art; and 
       FIG. 10  is a perspective view showing a connector construction in the prior art. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the drawings, a detailed description will be given of the best modes for implemented the present invention. 
     FIG. 1  is a perspective view showing a first embodiment. Electronic circuit packages  12  and  13  are support members each of which supports a ZIF (Zero Insertion Force) connector  14 . In  FIG. 1 , the electronic circuit packages  12  and  13  are circuit boards to which ZIF connectors  14 - 1  and  14 - 2 , respectively, are attached. The electronic circuit package  11  is a circuit board on which electronic parts such as LSIs  17  are mounted. The electronic parts such as the LSIs  17  generate heat and must thus be cooled by air. 
   In  FIG. 1 , the ZIF connectors  14 - 1 , an LSI  16 , and a wiring pattern  18  mounted under the electronic circuit package  12  are shown by broken lines. 
   The electronic circuit packages  12  and  13  have the ZIF connectors  14 - 1  and  14 - 2 , respectively, and the wiring patterns  18 . The ZIF connectors  14 - 1  and  14 - 2  and the wiring pattern  18  allow a plurality of electronic circuit packages  11  to be electrically connected. An electronic part such as the LSI  16  can be mounted on each of the electronic circuit packages  12  and  13 . 
   The electronic circuit packages  12  and  13  are arranged substantially parallel to each other. The connectors  14 - 1 , arranged on the electronic package  12  are provided parallel to and opposite the connector  14 - 2 , arranged on the electronic circuit package  13 . Accordingly, the connectors  14 - 1 , arranged on the electronic circuit  12 , are each connected to a ZIF connector  15 - 1  provided on the top side of a corresponding electronic circuit package  11 . The connectors  14 - 2 , arranged on the electronic circuit package  13 , are each connected to a ZIF connector  15 - 2  provided on the bottom side of the corresponding electronic circuit package  11 . 
   Each electronic circuit package  11  has the ZIF connectors  15 - 1  and  15 - 2  on its top and bottom sides, respectively, and the ZIF connectors  15 - 1  and  15 - 2  are to be connected to ZIF connectors  14 - 1  and  14 - 2  of the electronic circuit packages  12  and  13 , respectively. 
   A distance between the electronic circuit packages  12  and  13  is substantially equal to a distance between the ZIF connectors  15 - 1  and  15 - 2 . 
   When the electronic circuit package  11  is mounted between the electronic circuit packages  12  and  13 , terminals in the connectors  14 - 1  and  14 - 2  are brought into an open position. That is, the terminals in the connectors  14 - 1  and  14 - 2  are opened in a direction perpendicular to longitudinal directions of the connectors  14 - 1  and  14 - 2 , respectively. In this case, the ZIF connectors  15 - 1  and  15 - 2  can be slid in the longitudinal directions of the ZIF connectors  14 - 1  and  14 - 2 , respectively. The ZIF connectors  15 - 1  and  15 - 2  are guided by the ZIF connectors  14 - 1  and  14 - 2 , respectively, to their fully inserted positions. In the fully inserted positions, the terminals provided in the ZIF connectors  15 - 1  and  15 - 2  face the corresponding terminals in the ZIF connectors  14 - 1  and  14 - 2 . After the ZIF connectors  15 - 1  and  15 - 2  have been moved to their fully inserted positions, the terminals in the ZIF connectors  14 - 1  and  14 - 2  are brought into a closed position. The terminals in the ZIF connectors  14 - 1  and  14 - 2  are closed and thus electrically connected to the terminals in the ZIF connectors  15 - 1  and  15 - 2 , respectively. 
   Thus, the electronic circuit packages  12  and  13  are electrically connected via the electronic circuit package  11 . The different electronic circuit packages  11  can be electrically connected via the electronic circuit packages  12  or  13 . 
   It is assumed that a cooling airflow flows in a direction in which the electronic circuit packages  11  are mounted, that is, a direction parallel to the longitudinal directions of the ZIF connectors  14 - 1  and  14 - 2 . Then, the direction of the cooling airflow is parallel to the electronic circuit package  11 , so that the electronic circuit packages  12  and  13  do not interrupt the cooling airflow. Thus, the electronic circuit packages  11  are efficiently cooled. Furthermore, other devices can be mounted on or under the apparatus  10  without reducing the cooling efficiency. Thus, if the apparatus  10  is mounted in a standard rack or the like, multiple devices can be mounted in a vertical direction. 
     FIG. 2  shows that the apparatus  10 , which includes the electronic circuit packages  12  and  13 , is mounted in a housing  100  with an opening in a front portion of the housing  100 . The apparatus  10  is arranged between the opening in the front portion and a rear opening in a rear portion of the housing  100 .  FIG. 2  shows that the electronic circuit packages  12  and  13  are parallel to the top surface  101  of the housing  100 . However, the electronic circuit packages  12  and  13  have only to extend substantially parallel to a direction from the front portion to the rear portion of the housing  100 . For example, the electronic circuit packages  12  and  13  may be extended parallel to a side  102  of the housing  100 . 
   In  FIG. 2 , the connectors  14 - 1  and  14 - 2  are provided on the electronic circuit packages  12  and  13 , respectively, so that the longitudinal directions of the connectors  14 - 1  and  14 - 2  are substantially perpendicular to the front or rear portion of the housing  100 , that is, the connectors  14 - 1  and  14 - 2  are substantially parallel to the direction from the front portion to rear portion of the housing  100 . 
   The electronic circuit packages  11  are inserted and held between the electronic circuit packages  12  and  13  at an angle substantially perpendicular to the electronic circuit packages  12  and  13  through the opening formed in the front portion of the housing  100 . 
   Furthermore, the housing  100  is provided with a fan  103 . The fan  103  provides the apparatus  10  with a cooling airflow in the direction in which the electronic circuit packages  11  are inserted, that is, the longitudinal directions of the connectors  14 - 1  and  14 - 2 . The fan  103  is provided on the front or rear portion of the housing  100  or on both portions. The fan  103  may be provided at another position providing that a cooling airflow can be allowed to flow in the above described direction using means such as a guide. 
   Since the electronic circuit packages  12  and  13  are provided substantially perpendicularly to the front surface of the housing  100 , the direction of the airflow is parallel to the electronic circuit packages  12  and  13 . Thus, the electronic circuit packages  12  and  13  do not interrupt the airflow. Consequently, the electronic circuit packages  11  can be efficiently cooled. 
     FIG. 3  is a perspective view showing a second embodiment. 
   In  FIG. 3 , electronic circuit packages  22  and  23  are circuit boards to which ZIF connectors  24 - 1  and  24 - 2  are attached. Electronic circuit packages  21  are circuit boards on which electronic parts such as LSIs  27  are mounted. The electronic parts such as the LSIs  27  generate heat and must thus be cooled by air. 
   In  FIG. 3 , the ZIF connectors  24 - 1  and  24 - 2 , an LSI  26 , and a wiring pattern  28  that are mounted under the electronic circuit package  22  are shown by broken lines. 
   Each of the electronic circuit packages  22  and  23  have the ZIF connectors  24 - 2  and  24 - 1  and the wiring pattern  28 . The ZIF connectors  24 - 1  and  24 - 2  and the wiring pattern  28  allow a plurality of electronic circuit packages  21  to be electrically connected. An electronic part such as the LSI  26  can be mounted on each of the electronic circuit packages  22  and  23 . 
   The ZIF connectors  24 - 2  are arranged adjacent to the ZIF connectors  24 - 1  on each of the electronic circuit packages  22  and  23 . More specifically, the ZIF connectors  24 - 2  are arranged in an area adjacent to a short side of the ZIF connectors  24 - 1 . The ZIF connectors  24 - 1  and  24 - 2  may be arranged in overlapping areas. In this case, the ZIF connectors  24 - 1  and  24 - 2  are arranged alternately in a staggered format. 
   The longitudinal direction of the ZIF connectors  24 - 2  is substantially parallel to the longitudinal direction of the ZIF connectors  24 - 1 . However, the direction in which the electronic circuit packages  21  are inserted through the ZIF connectors  24 - 2  is substantially opposite to the direction in which the electronic circuit packages  21  are inserted through the ZIF connectors  24 - 1 . Consequently, the different electronic circuit packages  21  can be inserted from either end of the electronic circuit packages  22  and  23 . The electronic circuit packages  21  inserted through the ZIF connectors  24 - 1  can be electrically connected to the electronic circuit packages  21  inserted through the ZIF connectors  24 - 2 , via the electronic circuit package  22  or  23 . 
   The arrangement in  FIG. 3  may be varied so that the ZIF connectors  24 - 2  are arranged in an area adjacent to a long side of an outermost one of the ZIF connectors  24 - 1 . 
   Furthermore, if the apparatus  20  is mounted in the housing  100  such as the one shown in  FIG. 2 , openings are formed in the front and rear portions, respectively, of the housing  100 . The electronic circuit packages  21  are inserted between the electronic circuit packages  22  and  23  at an angle substantially perpendicular to the electronic circuit packages  22  and  23  via the front or rear opening in the housing  100 . 
     FIG. 4  is a perspective view showing a third embodiment. In  FIG. 4 , an electronic circuit package  32  is a circuit board to which ZIF connectors  33  are attached. Electronic circuit packages  31  are circuit boards on which electronic parts such as LSIs  36  are mounted. The electronic parts such as the LSIs  36  generate heat and must thus be cooled by air. 
   In  FIG. 4 , the ZIF connectors  33 , an LSI  35 , and a wiring pattern  37  mounted under the electronic circuit package  32  are shown by broken lines. 
   The electronic circuit package  32  has the ZIF connectors  33  and the wiring pattern  37 . The ZIF connectors  33  and the wiring pattern  37  allow a plurality of electronic circuit packages  31  to be electrically connected. An electronic part such as an LSI  35  can be mounted on the electronic circuit package  32 . 
   Each electronic circuit package  31  has a ZIF connector  34  on one side of it. The ZIF connector  34  of the electronic circuit package  31  is inserted through one of the ZIF connector  33  of the electronic circuit package  32  for electric connection. 
   When the electronic circuit package  31  is mounted on the electronic circuit package  32 , terminals in the ZIF connector  33  is brought into an open position. That is, terminals in the ZIF connector  33  are opened in a direction perpendicular to longitudinal direction of the ZIF connector  33 . In this case, the ZIF connector  34  can be slid in the longitudinal direction of the ZIF connector  33 . The ZIF connector  34  is guided by the connector  33  to its fully inserted position. In the fully inserted position, the terminals provided in the ZIF connector  34  face the corresponding terminals in the ZIF connector  33 . 
   After the ZIF connector  34  has been moved to its fully inserted position, the terminals in the ZIF connector  33  are brought into a closed position. The terminals in the ZIF connector  33  are closed and thus electrically connected to the group of terminals in the ZIF connector  34 . 
   The different electronic circuit packages  31  can be electrically connected together via the electronic circuit package  32 . 
   When the apparatus  30  is mounted in the housing  100 , the electronic circuit package  32  is provided perpendicularly to the front portion of the housing  100 . For example, the electronic circuit package  32  is provided parallel to the side  102  of the housing  100 . Alternatively, the electronic circuit package  32  is provided parallel to the top surface  101  of the housing  100 . The connector  33  is provided on the electronic circuit package  32  so that its longitudinal direction is parallel to the direction from the front portion to rear portion of the housing. 
   The housing  100  has an opening in its front portion. The electronic circuit packages  31  are mounted on the electronic circuit package  32  at an angle substantially perpendicular to the electronic circuit package  32  through the opening formed in the front portion of the housing  100 . 
   Furthermore, the housing  100  is provided with the fan  103 . The fan  103  provides the apparatus  30  with a cooling airflow in the direction in which the electronic circuit packages  31  are inserted, that is, the longitudinal directions of the connectors  33 . Accordingly, the fan  103  supplies a cooling airflow in the direction from the front portion to the rear portion of the housing. 
   As in the case of the first embodiment, the electronic circuit package  32  is positioned substantially perpendicularly to the front portion of the housing. Thus, the electronic circuit package  32  does not interrupt the airflow because the direction of the airflow is parallel to the electronic circuit package  32 . Consequently, the electronic circuit packages  31  can be effectively cooled. 
     FIG. 5  is a perspective view showing a fourth embodiment. In  FIG. 5 , an electronic circuit package  42  is a circuit board to which ZIF connectors  43 - 1  and  43 - 2  are attached. Electronic circuit packages  41  are circuit boards on which electronic parts such as LSIs  46  are mounted. The electronic parts such as the LSIs  46  generate heat and must thus be cooled by air. 
   In  FIG. 5 , the ZIF connectors  43 - 1 , an LSI  45 , and a wiring pattern  47  that are mounted under the electronic circuit package  42  are shown by broken lines. 
   This embodiment differs from the third embodiment in that the electronic circuit packages  41  can be mounted in the housing through either end of the electronic circuit package  42 . The ZIF connectors  43 - 2  are arranged -adjacent to the ZIF connectors  43 - 1  on the electronic circuit package  42 . More specifically, the ZIF connectors  43 - 2  are arranged in an area adjacent to a short side of the ZIF connectors  43 - 1 . The ZIF connectors  43 - 1  and  43 - 2  may be arranged in overlapping areas. In this case, the ZIF connectors  43 - 1  and  43 - 2  are arranged alternately in a staggered format. 
   The longitudinal direction of the ZIF connectors  43 - 2  is substantially parallel to the longitudinal direction of the ZIF connectors  43 - 1 . However, the direction in which the electronic circuit packages  41  are inserted through the ZIF connectors  43 - 2  is substantially opposite to the direction in which the electronic circuit packages  41  are inserted through the ZIF connectors  43 - 1 . Consequently, the electronic circuit packages  41  can be inserted into the housing from either end of the electronic circuit package  42 . The electronic circuit packages  41  inserted through the ZIF connectors  43 - 1  can be electrically connected to the electronic circuit packages  41  inserted through the ZIF connectors  43 - 2 , via the electronic circuit package  32 . 
   The arrangement in  FIG. 5  may be varied so that the ZIF connectors  43 - 2  are arranged in an area adjacent to a long side of an outermost one of the ZIF connectors  43 - 1 . 
   Furthermore, if the apparatus  40  is mounted in the housing  100  such as the one shown in  FIG. 2 , openings are formed in the front and rear portions, respectively, of the housing  100 . The electronic circuit packages  41  are mounted on the electronic circuit package  42  at an angle substantially perpendicular to the electronic circuit package  42  via the front or rear opening in the housing  100 . 
     FIG. 6  is a perspective view showing a high-density mounting structure according to a fifth embodiment. In  FIG. 6 , electronic circuit packages  52  and  53  are circuit boards to which ZIF connectors  54 - 1 ,  54 - 2 , and  54 - 3  are attached. Electronic circuit packages  51  are circuit boards on which electronic parts such as LSIs  57  are mounted. The electronic parts such as the LSIs  57  generate heat and must thus be cooled by air. 
   In the present embodiment, the ZIF connectors  54 - 3  are arranged adjacent to the ZIF connectors  54 - 1  only on the electronic circuit package  52 . The longitudinal direction of the ZIF connectors  54 - 3  is substantially parallel to the longitudinal direction of the ZIF connectors  54 - 1 . However, the direction in which the electronic circuit packages  51  are inserted through the ZIF connectors  54 - 3  is opposite to the direction in which the electronic circuit packages  51  are inserted through the ZIF connectors  54 - 1 . 
   If the electronic circuit package  51  is inserted from one side of the apparatus  50 , ZIF connectors  55 - 1  and  55 - 2  of the electronic circuit package  51  are connected to the corresponding ZIF connectors  54 - 1  and  54 - 2  of the electronic circuit packages  52  and  53 , respectively. On the other hand, if the electronic circuit package  51  is inserted from the opposite side of the apparatus  50 , the ZIF connector  55 - 1  of the electronic circuit package  51  is connected to the corresponding ZIF connector  54 - 3  of the electronic circuit package  52 . 
   As in the case of the second and fourth embodiments, openings are formed in the front and rear portions, respectively, of the housing  100 , in which the apparatus  50  is mounted. The electronic circuit packages  51  are inserted between the electronic circuit packages  52  and  53  via the front or rear opening in the housing  100 . 
     FIG. 7  is a perspective view showing connectors for implementing the first to fifth embodiments. 
   A ZIF connector  60  is supported on an electronic circuit packages, which is a support member. The ZIF connector  60  includes a female connector  62  and a edge portion  69  of the electronic circuit package  61 . The female connector  62  has an opening  67  in its short side to receive the edge portion  69  of the electronic circuit package  61 . A guide  68  is arranged along a long side of the female connector  62  and is connected to the opening  67 . The electronic circuit package  61  can be slid along the guide  68  in a longitudinal direction of the female connector  62 . The guide  68  guides the electronic circuit package  61  to a fully inserted position. 
   The ZIF connector  60  in  FIGS. 7 and 7   a  has a lock mechanism. The lock mechanism locks the edge portion  69  of the electronic circuit package  61  in the female connector  62  as the fully inserted position of the ZIF connector  60 . The lock mechanism includes a terminal opening and closing mechanism  64  and terminals  63 . The terminals  63  can operate to engage (as shown in  FIG. 7   a ) and disengage the edge portion  69  of the electronic circuit package  61  is accordance with an operation of the opening and closing mechanism  64 . If the edge portion  69  of the electronic circuit package  61  is inserted into the female connector  62  or disengaged or removed from the female connector  62 , the opening and closing mechanism  64  is operated. The operation of the opening and closing mechanism  64  opens the terminals  63  in a direction perpendicular to the longitudinal direction of the female connector  62 . On the other hand if the edge portion  69  of the electronic circuit package  61  is locked in the female connector  62 , the opening and closing mechanism  64  is operated. The operation of the opening and closing mechanism  64  closes the terminals  63  in the direction perpendicular to the longitudinal direction of the female connector  62 . 
   The electronic circuit package  61  has terminals  65  that can be connected to the female connector  62  along the edge portion  69  of the electronic circuit package  61 . The edge portion  69  of the electronic circuit package  61  is inserted into the opening  67  of the female connector  62  while the terminal  63  of the female connector  62  is open. The edge portion  69  of the electronic circuit package  61  is inserted into the female connector  62  while being slid in the longitudinal direction of the connector  62 . The electronic circuit package  61  is inserted into the female connector  62  to a fully inserted position of the female connector  62 . At the fully inserted position, the terminals  65  of the electronic circuit package  61  face the corresponding terminals  63  of the connector  62 . After the electronic circuit package  61  has been inserted to the fully inserted position, the connector contact opening and closing mechanism  64  is operated. The operation of the connector contact opening and closing mechanism  64  closes the terminals  63 . Once the terminals  63  are closed, the edge portion  69  of the electronic circuit package  61  is fixed to the female connector  62 . The terminals  63  and  65  are electrically connected, respectively. 
   If a connector is present on both opposite electronic circuit packages (for example, electronic circuit packages  12  and  13 ) as in the case of the first, second, and fifth embodiments, the electronic circuit package  61  has the terminal  65  at both edge portions of the electronic circuit package  61 . 
     FIGS. 8 and 8   a  are perspective views showing a second connector for implementing the first to fifth embodiments. 
   The second connector differs from the connector shown in  FIGS. 7 and 7   a  in that the electronic circuit package  61  has a male connector  66  at an edge portion  69  of the electronic circuit package  61 . The electronic circuit package  61  is electrically connected to the connector  62  via the male connector  66  (as shown in  FIG. 8   a ). 
   If a connector is present on both opposite electronic circuit packages (for example, electronic circuit packages  12  and  13  as in the case of the first, second, and fifth embodiments, the electronic circuit package  61  has a terminal  66  at both edge portions of the electronic circuit package  61 . 
   In the third and fourth embodiments, shown in  FIGS. 4 and 5 , the electronic circuit packages  32  and  42  may be provided on the bottom surfaces of the electronic circuit packages  31  and  41 , respectively, instead of their top surfaces. 
   The connectors used in the embodiment need not be ZIF connectors but may be any connectors that can be connected to a corresponding connector by inserting the corresponding connector along the longitudinal direction of the connector. 
   The present invention has been described in detail. However, it should be appreciated that various changes may be made to the present invention without departing from its spirits.