Abstract:
A spring connector includes: an electrically-conductive pin; an electrically-conductive tube, having the pin slidably received therein, the tube holding the pin in such a condition that at least part of the pin projects from one end of the tube in a first direction, and the other end of the tube being open; and a housing, including a hole portion which can receive the tube, and a slit exposing at least part of an outer peripheral surface of the tube to an exterior, the housing having a first wall portion opposed to the other end of the tube and formed with a projecting portion projecting in the first direction and fitting to the other end of the tube. The at least part of the outer peripheral surface of the tube which is exposed from the slit is electrically connectable to a board.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a connector used in an electronic equipment such as a cellular phone, and particularly to a right angle-type spring connector mounted horizontally on a board. 
   A cellular phone contains a battery as a main power source, and this battery and an equipment body are electrically connected together via a spring connector mounted on a printed wiring board of the equipment body. 
   With the achievement of a low profile design of cellular phones in recent years, there has been an increasing demand for a low-profile design of the spring connector. 
   A spring connector  100  of the related art is shown in  FIGS. 10 and 11 . 
   The spring connector  100  of the related art is surface mounted on a board  200 , and in  FIG. 10 ,  60  denotes a resin-made insulative housing,  70  denotes a tube made of an electrically-conductive material,  30  denotes a pin, and  40  denotes a spring. Within the housing  60 , the plurality of pins  30  having electrical conductivity and serving as contacts are received, together with the respective springs  40 , in the respective tubes  70 . 
   As shown in  FIG. 10 , the pin  30  is urged by the spring  40 , and is held in such a condition that its distal end is projected from an open end portion of the tube  70 . After the spring  40  and the pin  30  are inserted into the tube  70 , the open end portion of the tube  70  from which the pin  30  projects is press-deformed. Therefore, the pin  30  can slide within the tube  70 , but will not escape from the tube  70  to the exterior. 
   Hole portions  61  for the insertion and holding of the respective tubes  70  are provided in the housing  60 , and the tube  70  in which the pin  30  and the spring  40  are received and held therein is inserted into this hole portion  61 . A holding portion  62  is provided at the hole portion  61 , and is formed such that it projects radially inwardly in the hole portion  61 . A diameter (hole diameter) of this holding portion  62  is smaller than an outer diameter of a receiving portion  71  of the tube  70 , which is a portion on this tube for receiving the holding portion  62  when the tube  70  is inserted into the hole portion  61 . Therefore, the tube  70  is press-fitted into the hole portion  61  of the housing  60 , and is held therein.  FIG. 11  is a transverse cross-sectional view showing this holding portion  62  and the receiving portion  71 . As shown in  FIG. 11 , the holding portion  62  is so formed as to cover the receiving portion  71  in a peripheral direction so that the tube  70  will not fall from the housing  60  in a downward direction. 
   In the spring connector  100  of the related art, the following construction has been introduced in order to achieve its low-profile design. 
   Slits  63  communicating respectively with the hole portions  61  are formed in a lower portion of the housing  60 , and the tube  70  inserted into the hole portion  61  is exposed to the exterior of the housing  60  through this slit  63 . A mounting portion  72  for electrical connection to the board  200  is formed on an outer peripheral surface of the tube  70 , and the mounting portion  72  exposed from the slit  63  is connected by soldering or the like to a land (not shown) formed on the board  200 . Therefore, the height of the spring connector  100  on the board  200  is reduced in an amount corresponding to a saved lower portion of the housing  60  that is eliminated by such construction. 
   However, the following problems may occur in the spring connector  100  of the related art. 
   In the press-fit holding structure in which the diameter of the holding portion  62  of the housing  60  is set to a size smaller than the outer diameter of the receiving portion  71  of the tube  70 , thereby holding the tube  70 , deformation as shown in  FIG. 11  develops in the housing  60  because of the existence of the slits  63  formed in the lower portion of the housing  60  and of stresses produced by the press-fitting. Namely, when the stresses are applied to an upper portion of the housing  60 , which also has the slits  63  in its lower portion, this results in a problem in that the lower portions of the slits  63  are widened, so that the whole of the housing  60  is warped upwardly. 
   On the other hand, when the housing  60  holding the tubes  70  is solder mounted on the board  200 , solder is coated on the lands on the board  200 , and thereafter the housing  60  is mounted on the board  200 , with the mounting portions  72  of the tubes  70  being exposed from the respective slits  63 , and the soldering is then effected by heating. Accordingly, there is also a fear that the housing  60  may be further deformed by the influence of heat during the heating. 
   With the thus deformed housing  60 , its stable electrical connection to the board  200  can not be obtained. To avoid this deformation, it is necessary to thicken the upper portion of the housing  60  (the portion disposed above the hole portions  61 ), and therefore this leads to a drawback in that the overall height of the spring connector becomes large. 
   SUMMARY 
   It is therefore an object of the invention to provide a spring connector in which a thickness of an upper portion of a housing can be made thinner through provision of a normal holding structure that eliminating deformation of the resin housing, thereby achieving a low-profile design of the whole of the spring connector. 
   In order to achieve the object, according to the invention, there is provided a spring connector comprising: 
   an electrically-conductive pin; 
   an electrically-conductive tube, having the pin slidably received therein, the tube holding the pin in such a condition that at least part of the pin projects from one end of the tube in a first direction, and the other end of the tube being open; and 
   a housing, including a hole portion which can receive the tube, and a slit exposing at least part of an outer peripheral surface of the tube to an exterior, the housing having a first wall portion opposed to the other end of the tube and formed with a projecting portion projecting in the first direction and fitting to the other end of the tube, 
   wherein the at least part of the outer peripheral surface of the tube which is exposed from the slit is electrically connectable to a board. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view showing a first embodiment of a spring connector of the present invention. 
       FIG. 2  is an external perspective view of the first embodiment of the spring connector of the present invention. 
       FIG. 3  is an external perspective view showing a modified example of the first embodiment of the spring connector of the present invention. 
       FIG. 4  is a bottom view of the spring connector shown in  FIG. 3 . 
       FIG. 5  is a cross-sectional view of the spring connector of  FIG. 4  taken along the line A-A. 
       FIG. 6  is a cross-sectional view of the spring connector of  FIG. 4  taken along the line B-B. 
       FIG. 7  is a cross-sectional view in the cross-section A-A of  FIG. 5 , showing a manner of solder mounting. 
       FIG. 8  is a schematic view showing a second embodiment of the present invention. 
       FIG. 9  is an enlarged view of the present invention, showing portions surrounding a retaining portion of a tube shown in  FIG. 8   
       FIG. 10  is a schematic view showing a structure of a spring connector of the related art. 
       FIG. 11  is a transverse cross-sectional view showing holding portions of a housing and receiving portions of tubes shown in  FIG. 10 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Embodiments of the present invention will now be described with reference to  FIGS. 1 to 9 . The same construction as that of the above-mentioned related art will be designated by identical reference numerals, and explanation thereof will be omitted. 
     FIG. 1  is a schematic view of a first embodiment of a spring connector of the present invention, and  FIG. 2  is an external perspective view. In the spring connector  1  in the drawings,  10  denotes a resin-made insulative housing,  20  denotes a tube made of an electrically-conductive material,  30  denotes a pin, and  40  denotes a spring. 
   Hole portions  11  into which the tubes  20  can be inserted, respectively, are provided in the housing  10 , and slits  13  communicating respectively with the hole portions  11  are provided in a lower portion of the housing  10 , and the tube  20  inserted in the hole portion  11  is held within the housing  10  in such a condition that a mounting portion  22  formed on a generally longitudinally-central portion of an outer peripheral surface of the tube is exposed from the slit  13 . 
   The mounting portion  22  of the tube  20  exposed from the slit  13  in the housing  10  is connected by soldering to a land provided on a board  200 , so that the pin  30 , the tube  20  and the board  200  are electrically connected together. 
   The pin  30  is slidably received within, the tube  20 , and is urged in a forward direction (left direction in  FIG. 1 ) by the spring  40  also received within the tube  20 . Although a front end of the tube  20  is open so that a distal end of the pin  30  can project therefrom, a narrow portion  23  is formed at this front end so that the pin  30  urged by the spring  40  will not escape to the exterior of the tube  20 . 
   An open end portion  24  is provided at a rear end (the right side in  FIG. 1 ) of the tube  20  so that the pin  30  and the spring  40  can be inserted into the tube  20 . Namely, in an assembling process, the pin  30  and the spring  40  are inserted into the tube  20  through the open end portion  24 . 
   Upper open portions  15  corresponding respectively to the hole portions  11  are formed in a rear portion of an upper wall portion  14  of the housing  10 , and cylindrical projecting portions  17  also corresponding respectively to the hole portions  11  and projecting forwardly are formed integrally on a rear wall portion  16  of the housing  10 . These upper open portions  15  are elements which are required for a mold so that it can form the projecting portions  17  on the rear wall portion  16 , that is, within the housing  10 . Therefore, a length of projecting of the projecting portion  17  in a direction toward the front side of the housing  10  is smaller than a length of opening of the upper open portion  15  in the same direction. 
   The tube  20  into which the pin  30  and the spring  40  is inserted through the open end portion  24  is held within the housing  10  as a result of fitting of this open end portion  24  onto the projecting portion  17  of the housing  10 . With such structure, the spring  40  is received in a compressed condition within the tube  20 , and one end thereof abuts against the projecting portion  17 , and the other end thereof urges the pin  30 . Therefore, the pin  30  is held in the housing  10  and the tube  20 , and can be resiliently moved in the forward and backward directions. Incidentally, an outer diameter of the projecting portion  17  of the housing  10  is larger than an inner diameter of the open end portion  24  of the tube  20 , and the open end portion  24  is press-fitted on the projecting portion  17 . Therefore, the tube  20  is held in the housing  10  at its rear portion. 
     FIG. 3  shows a modified example of the above-mentioned first embodiment. 
   In  FIG. 3 , solder reinforcing terminals  50  are supported respectively on opposite side portions of the housing  10 , and are connected by soldering to lands formed on the board  200  in a manner similar to that of the mounting portion  22  of the tube  20 . However, unlike the connection between the mounting portion  22  of the tube  20  and the land on the board  200 , the connection of the solder reinforcing terminals  50  to the lands is effected only for mounting and fixing purposes, and electrical connection to a circuit, etc., on the board  200  is not made. With the use of the solder reinforcing terminals  50 , the more stable solder mounting can be effected. 
   The first embodiment will be described below in further detail using the above-mentioned modified example.  FIG. 4  is a bottom view of the modified example of the above-mentioned spring connector  1 , and  FIG. 5  is a cross-sectional view taken along the line A-A of  FIG. 4 , and  FIG. 6  is a cross-sectional view taken along the line B-B of  FIG. 4 . 
   As described above, the slits  13  for the solder mounting of the tubes  20  on the board  200  are formed in the lower portion of the housing  10 . Although a width of the slit  13  in its transverse direction (a left-right direction in  FIG. 4 ; a direction perpendicular to a longitudinal direction of the tube  20 ) needs to be sufficiently large to enable the mounting portion  22  of the tube  20  to be solder bonded to the land on the board  200 , this width should be smaller than the diameter of the tube  20 , and the width of the slit  13  is so adjusted that the hole portion  11  of the housing  10  can sufficiently cover the outer diameter of the tube  20 . In the present invention, the rear open end portion  24  of the tube  20  and the projecting portion  17  at the rear portion of the housing  10  are fitted together, so that the housing  10  thus sufficiently covers the outer diameter of the tube  20  in the longitudinal direction of the tube  20 . This prevents the tube  20  from being moved within the housing  10  in an upward-downward direction (in a direction of the sheet plane of  FIG. 4 ). 
   The cross-section A-A of the spring connector  1  shown in  FIG. 5  is a cross-sectional view of a position corresponding to the mounting portions  22  of the tubes  20  as shown in  FIG. 4 . Namely, the tubes  20  are soldered to the board  200  at the position shown in  FIG. 5 . On the other hand, the cross-section B-B of the spring connector  1  shown in  FIG. 6  is a cross-sectional view of a position corresponding to the solder reinforcing terminals  50  supported on the housing  10 , and in this position the tubes  20  are not soldered to the board  200 . 
   As shown in  FIG. 5  (and  FIG. 4 ), in the vicinity of the position corresponding to the mounting portion  22  of the tube  20 , that is, in the vicinity of the position where the tube  20  and the board  200  are solder bonded together, each opposite sides of the slit  13  are notched to form chamfered portions  18 , respectively. If the chamfered portions  18  are not provided respectively at the opposite sides of the slit  13  in the vicinity of the position where the tube  20  and the board  200  are solder bonded together, a phenomenon can occur in which solder beforehand coated on the land on the board  200  contacts the opposite side portions of the slit  13  at the time of mounting the spring connector  1  on the board  200 , so that much solder flows out to the opposite side portions of the slit  13  under the influence of surface tension of the solder. In this case, the solder is not sufficiently deposited on the mounting portion  22  of the tube  20 , and therefore the strength of bonding between the spring connector  1  and the board  200  is low. 
   On the other hand, in the position shown in  FIG. 6  (and  FIG. 4 ), that is, in the position where the tube  20  and the board  200  are not solder bonded together, the opposite sides of the slit  13  are not chamfered. This is because the phenomenon in which the solder is blocked by the opposite side portions of the slit  13  as described above will not occur in this position and also because no chamfered portion is required in the slit  13  due to the fact that the tube  20  can be held more stably by the hole portion  11  of the housing  10 . 
   The manner in which the spring connector  1  is solder mounted on the board  200  is shown in  FIG. 7 . In  FIG. 7 , the mounting portions  22  of the tubes  20  and the solder reinforcing terminals  50  are solder bonded respectively to the corresponding lands  210  on the board  200 . 
   In the first embodiment of the present invention, in place of using the press-fit holding structure of the related art according to the difference between the housing inner diameter and the tube outer diameter there is adopted the press-fit holding structure at the rear open end portion  24  of the tube  20  and the projecting portion  17  at the rear portion of the housing  10 , and by doing so, stresses will not be transmitted to the portion (the upper wall portion) of the housing  10  disposed above the hole portions  11 . Therefore, the deformation of the housing which is the problem with the related art does not occur, and the upper wall portion can be made thinner than that of the related art, and the low-profile design of the whole of the spring connector can be achieved. 
   Next, a second embodiment of the present invention will be described with reference to  FIGS. 8 and 9 . The second embodiment is similar in basic construction to the first embodiment, and therefore an identical construction will be designated by identical reference numerals, and explanation thereof will be omitted. 
     FIG. 8  is a schematic view of a spring connector  2 . In the spring connector  2 , in addition to the construction of the spring connector  1  of the first embodiment, an engagement portion  25  which projects radially outwardly from a tube  20  is formed at a rear portion of a tube  20 , which corresponds to an upper open portion  15  of a housing  10  when the tube  20  is inserted into a hole portion  11  of the housing  10 . The tube  20  is inserted into the hole portion  11  of the housing  10 , and when an open end portion  24  is press-fitted and held on a projecting portion  17  of the housing  10 , the engagement portion  25  is engaged with a retaining surface  19  which is the surface of an upper wall portion  14  of the housing  10  exposed to the upper open portion  15  (see  FIG. 9 ). 
   In the second embodiment of the present invention, in addition to the construction of the first embodiment, the engagement portion  25  of the tube  20  is engaged with the retaining surface  19  of the housing  10 , thereby preventing the tube  20  from forward displacement against a force pushing the tube  20  forward (for example, a force of a spring  40  urging a pin  30 ), and the stable holding can be effected. And besides, the retaining surface  19  is defined by the upper open portion  15 , and this upper open portion  15  is a secondary element which is required for a mold so that it can form the projecting portion  17  on the housing  10  as described above, and by using this, the holding structure is added. 
   The above embodiments are one example of the present invention, and can be suitably modified and changed within the scope of the appended claims.