Abstract:
A terminal ( 51 ) utilizes a torsional spring as its contact portion. The terminal is formed form a plate of sheet metal and first ( 52 ), second ( 53 ) and third ( 54 ) members are defined by two spaced apart slits formed in the plate. The members are formed in circular arcs and the first member has a free end that is extended out and away from of the arc and bent into a general U-shape to define the contact portion. The remainder of the plate serves as a base portion ( 57 ) for attaching the terminal to a connector or circuit board.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a battery connector and terminal therefor and more specifically to a torsion-coil style battery connector. 
       FIG. 7  is a perspective view illustrating a conventional battery connector terminal. 
     As shown in  FIG. 7 , the terminal is fabricated by stamping and bending a metal sheet, and includes a flat base  801 , a pair of first spring portions  802  and  803  connected to one side of the base  801 , and a second spring portion  804  connected to the free ends of the first spring portions  802  and  803  and bent so that the second spring portion  804  projects toward the front. The second spring portion  804  is connected to the first spring portions  802 ,  803  via interconnecting plate portion  806  which connects the free ends of the first spring portions  802  and  803  together. In the vicinity of the free end of the second spring portion  804 , a contact portion  805  is formed which contacts an opposite-side terminal such as an electrode of a battery. By elastic deformation of the first spring portions  802 ,  803  and the second spring portion  804 , the contact portion  805  is pressed against the battery terminal. 
     In this type of conventional terminal described above, larger portions of the first spring portions  802 ,  803  and the second spring portion  804  remain straight, and the curved portions thereof are short. The length of elastically deformable portions is insufficient, and thus flexibility is low, and the contact portion  805  cannot be displaced greatly towards the interconnecting plate portion (in the horizontal direction) when the contact portion  805  presses against the battery terminal. The second spring portion  804  acts as a cantilever where the top end serves as a supporting point and the lower end serves as a free end, when the contact portion  805  contacts the battery terminal, the contact portion  805  is displaced largely horizontally. At the same time, the contact portion is largely displaced vertically. Therefore, when the battery terminal is small vertically, like a thin battery which is used for a thin cellular phone, the contact portion  805  contacts the contact surface of the battery terminal, which causes a failure in electrical conduction or charging, damages the body of the equipment or device equipped with the opposite-side terminal, or damages the contact portion  805  itself. Additionally, even though the thickness of the terminal can be reduced sufficiently to accommodate a thin battery, a space becomes necessary for absorbing the aforementioned displacement amount of the contact portion in the vertical direction, which does not contribute to a thickness reduction of electronic equipment and device. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention, by solving the problems of the conventional terminal, to provide a connector terminal and a connector in which a cylindrical portion is formed by rolling a thin and strip-shaped plate member which includes a long and slender strip-shaped first, second and third members which are connected to one end of the first member and parallel to each other, and a portion of the first member is located between the second member and the third member. 
     A contact portion is formed by bending the first member near the other end to have a shape protruding toward one side of the cylindrical portion, the cylindrical portion is deformed elastically, an amount of displacement of the contact portion is large in the horizontal direction but small in the vertical direction, ensuring that the contact portion contacts with the battery opposite-side terminal, and the space required for the battery terminal is small. 
     Therefore, a connector terminal according to the present invention includes a base attached to a connector, a cylindrical portion connected to the base, and a projecting portion projecting toward one side of the cylindrical portion includes a contact portion, wherein the cylindrical portion includes a strip-shaped first member and strip-shaped, second and third members connected to one end of the first member and parallel to each other, the first, second, and third member forming a continuous circular arc with an central angle of 360 degrees or more, a portion of the first member being located between the second and third members, and the projecting portion is constituted by a portion of the first member adjacent to an free end thereof. 
     In another embodiment of the connector terminal according to the present invention, the contact portion receives a biasing force exhibited by the opposite-side terminal and directed toward the cylindrical portion. 
     In a further embodiment of the connector terminal according to the present invention, the contact portion is displaced by an elastic deformation of the cylindrical portion when the contact portion receives a biasing force exhibited by the opposite-side terminal. 
     In a still further embodiment of the connector terminal according to the present invention, the contact portion is displaced toward the cylindrical portion. 
     In a yet further embodiment of the connector terminal according to the present invention, a straight line which indicates a direction of the biasing force that the contact portion receives from the opposite-side terminal is located closer to the base portion than to a central axis of the cylindrical portion. 
     In a further embodiment of the connector terminal according to the present invention, a straight line which indicates a direction of biasing force that the contact portion receives from the opposite-side terminal passes through a central axis of the cylindrical portion. 
     In a yet further embodiment of the connector terminal according to the present invention, the first member is located at a center of the connector terminal in a widthwise direction. 
     In a still further embodiment of the connector terminal according to the present invention, the first member, the second member, and the third member are connected integrally via an interconnecting portion, and have a shape of two-pronged fork before forming the circular arc of the terminal. 
     In a yet further embodiment of the connector terminal according to the present invention, the first member includes a slit formed therein extending longitudinally at least in the projecting portion, and the contact portion is divided in a width direction of the connector terminal. 
     A connector according to the present invention is provided with a connector terminal including a base attached to the connector, a cylindrical portion connected to the base, and a projecting portion projecting toward one side of the cylindrical portion which includes a contact portion, and a housing accommodating therein the connector terminal, wherein the cylindrical portion includes strip-shaped first member, second member and third member which are connected to one end of the first member and parallel to each other, the first member, the second member, and the third member forming a continuous circular arc with a central angle of 360 degrees or more, a portion of the first member is located between the first member and the third member, the projecting portion is constituted by a portion of the first member adjacent to a free end thereof, the housing includes an accommodating recessed portion for accommodating the connector terminal, and the accommodating recessed portion accommodates one, two or more connector terminals. 
     In another embodiment of the connector according to the present invention, the housing includes an open portion communicating with the accommodating recessed portion, and the contact portion projects from the open portion. 
     In a further embodiment of the connector according to the present invention, the contact portion is displaced elastically by the cylindrical portion when the contact portion receives a biasing force exhibited by the battery terminal, and the housing includes a terminal-receiving portion which contacts with the displaced contact portion. 
     According to the present invention, a connector terminal includes a cylindrical portion formed by rolling a strip-shaped plate member which includes a long slender strip-shaped first member, and long and slender strip-shaped second and third members which are connected to one end of the first member and parallel to each other so that a portion of the first member is located between the second and third members, and a contact portion which is formed by bending a portion of the first member adjacent to the other end thereof and has a shape protruding to one side of the cylindrical portion. Because of this, the cylindrical portion deforms elastically, and the amount of displacement of the contact portion is large horizontally but small vertically, thus ensuring that the contact portion comes into contact with the small opposite-side terminal. Further, a space exclusively occupied by the whole connector terminal can be small. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a connector according to an embodiment of the present invention; 
         FIG. 2  is a perspective view illustrating a state where an opposite-side device is being fitted to the connector according to the embodiment of the present invention; 
         FIG. 3  is a cross-sectional view illustrating a main part of the connector; 
         FIG. 4  is a perspective view of a terminal according to present invention; 
         FIGS. 5A and 5B  are views illustrating an initial state of the terminal; 
         FIGS. 6A and 6B  are views illustrating a state after displacement of the terminal; and, 
         FIG. 7  is a perspective view illustrating a conventional terminal. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings. 
     In the drawings, reference numeral  1  represents a connector which is provided with a terminal  51  serving as a connector terminal in this embodiment, and the connector is attached to electronic equipment (not shown). The electronic equipment is mounted an opposite-side device  101  (such as a battery) via the connector  1  which connects to the electrical circuits of the electronic equipment. ( FIG. 2 ) 
     The opposite-side device  101  described above may be any type of equipment as long as it can be mounted on an electronic equipment, and may be an electric connector, for example, but the opposite-side device  101  is described as a battery in this embodiment. In the drawings, the opposite-side device (battery)  101  includes a thin box-shaped body  111 , and a one or more opposite-side terminals  151  exposed on one side of the body  111 , and the battery is typically loaded in a thin cellular phone. In this case, the electric equipment to which the connector  1  is attached is the cellular phone or a battery charger for the cellular phone. 
     As shown in  FIGS. 1 &amp; 2 , the connector  1  includes a housing  11  which is formed from an insulating material, and terminals  51 , each of which is formed through the stamping and bending of a conductive material and are accommodated in an accommodating recessed portion  13 , and has a contact portion  59   a  which projects outwards from an opening portion  12 . Furthermore, an auxiliary mounting bracket  91 , commonly known as a filling nail, is attached to both sides of the housing  11  for fixing the connector  1  to the electronic equipment. 
       FIG. 3  illustrates a main part of the connector according to the embodiment of the present invention, and  FIG. 4  is a perspective view of a terminal. 
     As shown in  FIG. 3 , the housing  11  of the connector  1  includes three accommodating recessed portions  13  which are separate from each other, and the terminals  51  are accommodated in these portions  13 , respectively. The contact portions  59   a  which contact the battery terminals  151  project outward from the opening portions  12 , spatially communicating with the accommodating recessed portions  13 . The number and location of accommodating recessed portions  13  may be appropriately determined, and it is not necessarily required that the terminals  51  are accommodated in all accommodating recessed portions  13 . The housing  11  is provided with terminal receiving portions  14  which can receive projecting portions  59  when the terminals  51  receive a biasing force, respectively, from the opposite-side terminals  151  and are displaced. 
     Each of the terminals  51  is formed by a thin, long metallic plate which is formed in a predetermined shape by stamping. 
     As shown in  FIG. 4 , the terminal  51  includes a flat plate base  57 , a cylindrical portion  58  located above the base portion  57 , a projecting portion  59  connected to the cylindrical portion  58  which projects toward the side, and has an approximately triangular side shape, and an interconnecting portion  60  which interconnects the base  57  and the cylindrical portion  58  together. The cylindrical portion  58  includes a long and thin strip-shaped first member  52 , and long and thin strip-shaped second and third members  53 ,  54  which are connected to one end of the first member  52  and are parallel to each other. 
     The first member  52 , and the second and third members  53 ,  54  are integrally connected to each other via the interconnecting portion  55 , and, prior to forming the cylindrical portion  58 , the first member  52 , and the second and third members  53  and  54  are as a whole, a strip-shaped member extending straight with a shape of a thin two-pronged fork. In this case, the first member  52  corresponds to the handle of the fork, and the second and third members  53  and  54  connected to each other by interconnecting portion  55 , correspond to two prongs of the fork. Also, a long and thin aperture  56  is formed between the second and third members  533 ,  54 . In a state before forming the cylindrical portion  58  by bending the plate, this aperture  56  extends to be in registration with the line of extension of the first member  52 , and is rectangular that is wider than the first member  52 . 
     By bending a portion of the first member  52  adjacent to the interconnecting portion  55 , and portions of the second and third members  53 ,  54  adjacent to the interconnecting portion  55  into a circular arc shape, the cylindrical portion  58  is formed. The first, second and third members  52 ,  53  and  54  form a continuous circular arc. This arc is formed so that the curvature of the first member  52  and the curvature of the second and third members  53 ,  54  are substantially the same. 
     Although the circular arc is formed so that the curvature of the first member  52  and the curvature of the second and third members  53 ,  54  are substantially the same, the circular arc may be formed so that the curvature of the first member  52  is larger than that of the second and third members  53 ,  54 , or the curvature of the first member  52  maybe smaller than that of the second and third members  53 ,  54 . The circular arc is formed so that a portion of the first member  52  may be located within the aperture  56 . Therefore, the cylindrical portion  58  is formed so that its elevational view presents almost a perfect circle. The central angle of the arc formed by the first member  52  and the second and third members  53 ,  54  is 360 degrees or more. The first member  52  and the second and third members  53 ,  54  are bent and rolled for more than one complete revolution so as to form the cylindrical portion  58  shown. 
     As illustrated in the drawings, the central angle of the arc formed by the first member  52  and the second and third members  53 ,  54  is approximately 540 degrees. The series of strips that include the first member  52  and the second and third members  53 ,  54  are bent and rolled for approximately one complete and a half revolution so as to form the cylindrical portion  58 . The central angle of the arc is not limited to that shown example in the drawings, and may be any angle as long as it is 360 degrees or more. 
     The projecting portion  59  is formed in the first member  52  adjacent to the opposite side of the interconnecting portion  55 , or in other words, an area near the free end. The first member  52  includes a first flat plate portion  52   a  extending towards the tangent from the peripheral surface of the cylindrical portion  58 , and the projecting portion  59  is connected to the first flat plate portion  52   a . The first flat plate portion  52   a  extends approximately horizontally and is approximately parallel to the base  57 . 
     The projecting portion  59  is connected to the first plate portion  52   a  via a first curved portion  52   b  which is curved gently, and includes a first slope portion  59   b  extending obliquely downward to an external side of the cylindrical portion  58  (to the right of  FIGS. 3 and 4 ) from the first flat plate portion  52   a , the contact portion  59   a  serving as an end portion of the projecting portion  59  which is connected to the lower end of the first slope portion  59   b , a second slope portion  59   c  extending obliquely downward towards the inside of the cylindrical portion  58  (to the left side of  FIGS. 3 and 4 ) from the contact portion  59   a , and a free end portion  59   d  which is the extreme end of the second slope portion  59   c  and a free end of the terminal  51 . Note that the contact portion  59   a  is curved, and the surface on the external side thereof (the right of  FIGS. 3 and 4 ) is a smoothly curved surface. 
     The interconnecting portions  60  are formed in the ends of the second and third members  53  and  54  on the opposite side of the interconnecting portion  55 , and the second and third members  53  and  54  are integrally connected to the base portion  57  via the interconnecting portions  60 . The interconnecting portions  60  include second flat plate portions  53   b  and  54   b  extending to the tangible direction from the peripheral surface of the cylindrical portion  58 , third flat plate portions  53   c  and  54   c  extending to the external side of the cylindrical portion  58  from the base  57 , and interconnecting curved portions  53   a  and  54   a  which are curved at approximately 180 degrees and interconnect the second flat plate portions  53   b  and  54   b  and the third flat plate portions  53   c  and  54   c . The side view ( FIG. 5A ) of the interconnecting portions  60  is approximately U-letter shape. The free end portion  59   d  of the projecting portion  59  exists within a space defined between the interconnecting curved portions  53   a  and  54   a  on laterally opposite sides. 
     Further, the base  57  is a rectangular flat plate, the third flat plate portions  53   c  and  54   c  are connected to one end side of the base portion  57 , and tail portion  57   a  is connected to the other end side. The tail portion  57   a  is connected to a connection pad of the electronic equipment such as by soldering. A plurality of mounting projections  57   b  may be formed on both sides of the base  57 . The terminals  51  mounted within the accommodating recessed portions  13  of the housing  11  are firmly secured as the mounting projections  57   b  grasp the inner walls of the accommodating recessed portions  13 . 
     The operation of the terminal  51  is now described. in the initial state where the opposite-side device  101  is not connected to the connector  1 , and the contact portion  59   a  does not in contact with the terminal  151  ( FIG. 2 ), the terminal  51  takes a shape as best shown in  FIGS. 5A and 5B . In this case, the cylindrical portion  58  holds a shape close to a perfect circle, the second flat plate portions  53   b  and  54   b  are approximately parallel to the base portion  57  and extend in an approximately horizontal direction, the first flat plate portion  52   a  is approximately parallel to the base  57  and extends in an approximately horizontal direction, and the free end portion  59   d  enters and exists in a space defined between the interconnecting curved portions  53   a  and  54   a.    
     When viewed from the side of the cylindrical portion  58 , the contact portion  59   a  is located closer to the base  57  in comparison with the location of the central axis C 1  of the cylindrical portion  58  in an fore and aft direction (the right and left direction in  FIGS. 5A and 6A ), in other words, the contact potion  59   a  is formed to occupy a position located on a side lower than the position of the central axis C 1 . 
     Next, from the state depicted in  FIG. 2 , the opposite-side device  101  is moved towards the connector  1 , allowing the opposite-side device  101  to be connected to the connector  1 . In this case, since the opposite-side terminal  151  of the opposite-side device  101  is pressed against the contact portion  59   a  of the projecting portion  59  projecting towards the front from the housing  11 , the contact portion  59   a  receives a biasing force towards the cylindrical portion  58 , that is, to the backwards (to the left side in  FIG. 5A ) from the battery terminal  151 . Furthermore, since the contact portion  59   a  is formed to be situated lower than the central axis C 1 , once the contact portion  59   a  receives the biasing force from the battery terminal  151 , the first curved portion  52   a  is deformed and displaced downward as well. As a result, the terminal  51  is elastically deformed, and changed into the shape illustrated in  FIGS. 6A and 6B , and the contact portion  59   a  is displaced towards the backward and downward so as to be directed toward the cylindrical portion  58 . 
     When receiving the biasing force to the back from the battery terminal  151 , the first member  52 , and the second and third members  53  and  54 , and the projecting portion  59  are deformed. This means that the circular arc portion of the first member  52  is displaced backward while being deformed into a slightly irregular circle, and, in association with this, the contact portion  59   a  is displaced backward as the circular arc portions of the second and third members  53  and  54  in the vicinity of the interconnecting portion  55  are also displaced backward while the curvatures thereof are reduced, and further, the contact portion  59   a  is displaced backward and downward because the first curved portion  52   a  is deformed while being bent downward and the projecting portion  59  is displaced backward and downward. The cylindrical portion  58  becomes a slightly irregular circle in stead of a perfect circle, and the first curved portion  52   a  is also deformed as shown in  FIG. 6A . The main deformation occurs in the cylindrical portion  58 , and the contact portion  59   a  is displaced downward only slightly even if the contact portion  59   a  is largely displaced backward, in other words, the amount of horizontal displacement of the contact portion  59   a  is large, and the amount of vertical displacement is small. 
     When reducing the size of the connector  1  width wise or reducing the thickness of the battery device  101 , since the contact portion  59   a  is formed at a position lower than the central axis C 1 , any biasing force exhibited by the battery  151  is successfully absorbed at two points by displacements of the cylindrical portion  58  and the projecting portion  59 . The connector  1  and the battery  101  may be easily reduced in the size thereof, respectively. 
     The terminal  51  in which the contact portion  59   a  is formed at an equivalent location to the central axis C 1  may be used, and although the cylindrical portion  58  receives a biasing force from the battery terminal  151  and is deformed elastically, and the contact portion  59   a  is displaced downward only, the contact portion  59   a  is not deformed downward. This is because the biasing force that is applied to the contact portion  59   a  generates so as to transmit in only a direction towards the central axis C 1 . In this case, because it is not necessary to consider vertical displacement, the size of the connector  1  can be reduced in the thickness direction. 
     A portion of the first member  52  is formed to be positioned in the aperture  56 , and the terminal  51  is formed approximately symmetrically relative to the central line C 2  in the horizontal direction of the first member  52 , the contact portion  59  is prevented from being displaced in directions other than the horizontal direction and the vertical direction, and the contact portion  59  is smoothly displaced in the horizontal and vertical directions. 
     Although the second and third members  53 ,  54  are formed to have approximately the same width, even if the second and third members  53  and  54  are formed to have different widths from one another, the contact portion  59   a  is still prevented from being displaced in directions other than the horizontal direction and the vertical direction as long as a portion of the first member  52  is formed to be placed in the aperture  56 , and therefore the contact portion  59   a  can be smoothly displaced in the horizontal direction and the vertical direction. 
     Therefore, the free end portion  59   d  of the projecting portion  59  can be displaced backward without interfering with the base  57 . The entire projecting portion  59  is smoothly displaced without interfering with other areas of the base portion  57  and the like, and a biasing force applied by the battery terminal  151  is absorbed flexibly, and thus no unnecessary force is applied to the entire connector  1 . 
     The amount of vertical displacement of the contact portion  59   a  is small, even if the dimension of the battery terminal  151  is small vertically, and the contact portion  59   a  does not miss the battery terminal  151 , ensuring that the contact between the contact portion  59   a  and the battery terminal  151  is maintained. 
     The terminal receiving portion  14  is formed in the housing  11 , even if the biasing force applied from the battery terminal  151  is large and the projecting portion  59  is greatly displaced downward, the projecting portion  59  comes into contact with the terminal receiving portion  14 , and the projecting portion  59  is prevented from being excessively displaced downward, ensuring that the contact of the contact portion  59   a  with the battery terminal  151  is reliably maintained. If a biasing force is still applied even after the terminal  51  has come into contact with the terminal receiving portion  14 , the cylindrical portion  58  receives the force and is displaced. Therefore, the terminal  51  is elastically deformed without having permanent plastic deformation, thus enabling the terminal  51  to maintain reliable contact with the opposite-side terminal  151 . 
     Further, since the length of members forming the cylindrical portion  58  which serves as a mainly deformed portion is long, in other words, the continuous circular arc formed by the first member  52  and the second and third members  53  and  54  is long, the spring length becomes large, and therefore the amount of displacement of the contact portion  59   a  horizontally in large. The tolerance of relative positions of contact portion  59   a  and the battery terminal  151  is large, and, even if relative positions of the contact portion  59   a  and the battery terminal  151  are largely changed due to dimensional errors of the body  111  of the opposite-side device  101 , dimensional errors of the electronic equipment mounting, or an error in attaching the electronic equipment to the connector  1 , the contact with the battery terminal  151  is maintained as the contact portion  59   a  displaces widely. 
     The cylindrical portion  58 , has a large spring length, even if the contact portion  59   a  is greatly displaced horizontally and the amount of displacement of the outer diameter and that of the position of the cylindrical portion  58  are small. Occurrence of either the deformation of the first flat plate portion  52   a  or that of the interconnecting portions  60  is the smallest. The dimension of the terminal  51  hardly changes vertically and horizontally, and the dimensions of the accommodating recessed portions  13  may be reduced vertically and horizontally, thus reducing the size of the connector  1 . Also, since the spring length is large, any force applied to the cylindrical portion  58  and other portions are dispersed, preventing damages and plastic deformation of the terminal  51 . 
     A portion of the first member  52  is located in the gap portion  56  between the second and third members  53  and  54 , the terminal  51  has a symmetrical shape relative to the width direction (a direction perpendicular to the drawing in  FIG. 5A ), and the first member  52  is located at the center of the terminal  51  in the width direction. Therefore, even if the contact portion  59   a  receives a backward biasing force applied from the battery terminal  151 , no stress component or bending movement relative to the width of the terminal  51  is generated. As a result, excessive force is not applied to the entire terminal  51 , and therefore a no damage and no plastic deformation occurs in the terminal  51 . The terminal  51  is hardly displaced widthwise and the dimensions of the accommodating recessed portions  13  are reduced widthwise, and the size of the connector  1  can be reduced. 
     The projecting portion  59  of the first member  52  may include a slit longitudinal. By providing the slit, the projecting portion  59  is divided into a plurality of portions widthwise, and the contact portion  59   a  is also divided into a plurality of portions widthwise. Since a plurality of contact portions  59   a  contact the battery terminal  151 , the terminal  51  ensure that the connection with the battery terminal  151  is maintained. 
     The terminal  51  contains a base portion  57  for attachment to a connector  1 , a cylindrical portion  58  connected to the base portion  57 , and a projecting portion  59  projecting toward one side of the cylindrical portion  58  and a contact portion  59   a . The cylindrical portion  58  includes a strip-shaped first member  52 , as well as strip-shaped second member  53  and third member  54  which are connected to one end of the first member  52  and parallel to each other. The first, second, and the third members  52 ,  53  and  54  form a continuous circular arc with an central angle of 360 degrees or more and a portion of the first member  52  is located between the second member  53  and the third member  54 , and the projecting portion  59  is a portion of the first member  52  adjacent to an free end thereof. 
     When the contact portion  59   a  receives a biasing force applied by the opposite-side terminal  151 , the cylindrical portion  58  is elastically deformed, and the contact portion  59   a  is displaced backward. Therefore, the amount of displacement of the contact portion  59   a  in the horizontal direction becomes large, and is small in the vertical direction. Hence, even if the battery terminal  151  is small, contact between the terminal  51  and the battery terminal  151  is reliably maintained. Since an amount of displacement of the external shape of the entire terminal  51  is small, the space exclusively occupied by the terminal  51  is small, so the size of the connector  1  is reduced. 
     The present invention is not limited to the above-described embodiments, and may be changed in various ways based on the gist of the present invention, and these changes are not eliminated from the scope of the present invention.