Patent Publication Number: US-8992265-B2

Title: Plug-type connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an insertion-type connector, and in particular to a charging connector or high-current connector, having a housing of an electrically insulating material and having at least one first contact-making member which is of an electrically conductive material and which is arranged in the housing, the housing having an insertion end which is designed for connection by insertion to a complementary insertion-type connector and having a cable end which is designed for electrical and mechanical connection to an electrically conductive cable, and the at least one first contact-making member having a free end which is adjacent the insertion end. 
     2. Description of Related Art 
     A high-current insertion-type connector for transmitting electric currents is known from DE 20 2010 010 827 U1. This has a housing of electrically conductive material which is designed for mechanical and electrical connection to a cable and which has an open end for the insertion of a mating insertion-type connector made of an electrically conductive material. Also provided is a contact-making member which is so arranged and formed in the housing that it makes electrical contact with a contact surface and produces contact-making pressure between the housing and the mating insertion-type connector inserted therein. The contact-making member has at least one annular helical spring. 
     SUMMARY OF THE INVENTION 
     Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to improve an insertion-type connector of the above kind to the effect that contacts able to be moved relative to one another are possible within the insertion-type connector. 
     This object is achieved in accordance with the invention by an insertion-type connector of the above kind which has the features characterized in the claims. 
     The above and other objects, which will be apparent to those skilled in the art, are achieved in the present invention which is directed to an insertion-type connector including: a housing of an electrically insulating material, the housing having an insertion end which is designed for connection by insertion to a complementary insertion-type connector and having a cable end which is designed for electrical and mechanical connection to an electrically conductive cable; at least one first contact-making member which is of an electrically conductive material and which is arranged in the housing, the at least one first contact-making member having a free end which is adjacent the insertion end, and a first blade-like portion; at least one second contact-making member which is of an electrically conductive material and which has an electrically conductive connection to the first contact-making member and is arranged in the housing, the second contact-making member having a second blade-like portion, and an end adjacent the cable end of the insertion-type connector for electrical connection to the cable; wherein the blade-like portions of the two contact-making members are arranged parallel to one another and face towards one another in a direction perpendicular to themselves and in a region of overlap, the blade-like portions at least partly overlap and are at a predetermined distance from one another; there being provided, in the region of overlap, between the blade-like portions which face towards one another and for the electrically conductive connection of the first contact-making member to the second contact-making member, at least one helical spring which is of an electrically conductive and resilient material and which makes electrical contact with the first contact-making member with a first contact-making pressure, on the first blade-like portion, at at least one first contact surface and which makes electrical contact with the second contact-making member with a second contact-making pressure, on the second blade-like portion, at at least one second contact surface, the helical spring being of an annular form and defining an area in space within the annulus, the area being parallel to a longitudinal axis of the helical spring at its boundary relative to the helical spring, the helical spring being so arranged that at least part of the area is arranged between and parallel to the blade-like portions in the region of overlap, and the helical spring fitting partly around the surface of the first contact-making member. 
     The helical spring may include turns wound at an oblique angle. The helical spring is arranged between the two blade-like portions, in the region of overlap, such that at least one portion of a first axial side of the annular helical spring makes electrical and mechanical contact with the first blade-like portion and that at least one portion of a second axial side of the annular helical spring which is opposite from the first axial side makes electrical and mechanical contact with the second blade-like portion. 
     The distance between the blade-like portions of the contact-making members is smaller than the outside diameter of the helical spring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective view of a preferred embodiment of insertion-type connector according to the invention in a state where the contact-making members are withdrawn; 
         FIG. 2  is a perspective view of the insertion-type connector shown in  FIG. 1  in a state where the contact-making members are fully extended; 
         FIG. 3  is a partly broken-away perspective view of the insertion-type connector shown in  FIG. 1 ; 
         FIG. 4  shows the insertion-type connector shown in  FIG. 1  when a first contact-making member is in a second, extended, position; and 
         FIG. 5  shows the insertion-type connector shown in  FIG. 1  when a first contact-making member is in a first, withdrawn, position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     In describing the preferred embodiment of the present invention, reference will be made herein to  FIGS. 1-5  of the drawings in which like numerals refer to like features of the invention. 
     In an insertion-type connector of the above kind, provision is made in accordance with the invention for at least one second contact-making member which is of an electrically conductive material and which has an electrically conductive connection to the first contact-making member to be arranged in the housing, the first contact-making member having a first blade-like portion and the second contact-making member having a second blade-like portion, the second contact-making member having an end, adjacent to the cable end of the insertion-type connector, which is designed for electrical connection to the cable, the blade-like portions of the two contact-making members being arranged parallel to one another and to face towards one another in such a way that, in a direction perpendicular to themselves and in a region of overlap, the blade-like portions at least partly overlap and are at a predetermined distance from one another, there being provided, in the region of overlap, between the blade-like portions which face towards one another and for the electrically conductive connection of the first contact-making member to the second contact-making member, at least one helical spring which is of an electrically conductive and resilient material and which makes electrical contact with the first contact-making member with a first contact-making pressure, on the first blade-like portion, at the at least one first contact surface, and which makes electrical contact with the second contact-making member with a second contact-making pressure, on the second blade-like portion, at the at least one second contact surface. 
     This has the advantage that the first contact-making member can be moved relative to the housing and the second contact-making member without the electrical contact between the two contact-making members being adversely affected when this is done. This makes the point of electrical contact particularly suitable for transmitting high currents, such for example as ones of an intensity of 100 to 400 A or more, and, because of the movable first contact-making member, it can at the same time be equipped with a means of protection against electric shock for the electrical contacts of the insertion-type connector. 
     Particularly good electrical contact produced by a high contact-making pressure is achieved by virtue of the helical spring having turns wound at an oblique angle. 
     A particularly large number of contact surfaces together with a commensurate improvement in the electrical properties of the insertion-type connector are obtained by making the helical spring of an annular form. 
     A particular even distribution of the contact-making pressure over the contact surfaces is achieved by arranging the annular helical spring between the two blade-like portions, in the region of overlap, in such a way that at least one portion of a first axial side of the annular helical spring makes electrical and mechanical contact with the first blade-like portion and that at least one portion of a second axial side of the annular helical spring which is opposite from the first axial side makes electrical and mechanical contact with the second blade-like portion. 
     A particularly large number of contact surfaces between the helical spring and the blade-like portions of the contact-making members are obtained in the region of overlap by virtue of the fact that the annular helical spring defines an area in space within the annulus, the area being parallel to a longitudinal axis of the helical spring at its boundary relative to the helical spring and the helical spring being so arranged that at least part of this area is arranged between and parallel to the blade-like portions in the region of overlap. 
     Particularly good mechanical fixing of the helical spring to the first contact-making member is achieved by arranging the helical spring in such a way that it fits partly round the surface of the first contact-making member. 
     A further increase in the contact-making pressure together with a commensurate improvement in the electrical properties of the insertion-type connector is achieved by tilting the turns of the helical spring relative to a longitudinal axis of the helical spring by making the distance between the blade-like portions of the contact-making members smaller than the outside diameter of the helical spring. 
     The preferred embodiment of insertion-type connector according to the invention which is shown in  FIGS. 1 to 5  comprises a housing  10  having an insertion end  12  and a cable end  14 . A cover  16  is provided on the housing  10  at the insertion end  12 . The insertion end  12  is designed for connection by insertion to, or in other words plugging together with, a complementary insertion-type connector (not shown), when at least one electrical contact is to be made between the insertion-type connector according to the invention and the complementary insertion-type connector. For this purpose, there are provided in the housing  10  at least one pair of contact-making members made of an electrically conductive material comprising a first contact-making member  18  and a second contact-making member  20 , as can be seen from  FIG. 3 . For reasons of greater clarity, only one pair of these contact-making members  18 ,  20  are shown in  FIG. 3  but the illustrative embodiment does in fact have seven such pairs. For reasons of greater clarity, the mounting and guidance of the contact-making members  18 ,  20  in the housing  10  are likewise not shown in any of the drawings. The first contact-making member  18  has a free end  22  which is adjacent the insertion end  12 . Arranged on a terminal face of the free end  22  is an end-cap  24  made of an electrically insulating material which completely covers it. 
     The first contact-making member  18  of any given pair is movable relative to the housing  10  and the second contact-making member  20  between a first position as shown in  FIGS. 1 and 5  and a second position as shown in  FIGS. 2 and 4 . The second contact-making member  20  is arranged in a fixed position relative to the housing  10 . For reasons of greater clarity, a mechanism for moving the first contact-making members  18  is not shown in the drawings. In the first position, the first contact-making member  18  is drawn back into a space bounded by the housing  10  and the cover  16 . In the second position, the first contact-making member  12  is slid out of the housing  10  through a given aperture  26  in the cover  16  and thus projects beyond the cover  24  and the housing  10  in the direction towards the insertion end  12 . 
     In the first position, there is thus protection against unwanted electric shock of an operator by the first contact-making members  18  when the insertion-type connector according to the invention is not inserted in a complementary insertion-type connector and the insertion end  12  is thus freely accessible. At the insertion end  12  it is only the electrically insulating cover  16  and electrically insulated housing  10  together with the end-caps  24  which are exposed. A voltage can thus be applied to the first contact-making members  18  even when the insertion-type connector according to the invention is in the unplugged state without this creating any risk to an operator due to unwanted contact with the first contact-making members  18  at an electrically conductive point. 
     Once the insertion-type connector according to the invention has been plugged together with a complementary insertion-type connector, the first contact-making members  18  are extended through the cover  16  from the first position to the second position, the first contact-making members  18  of each pair thus making contact electrically with corresponding contact-making members in the complementary insertion-type connector. Conversely, before the insertion-type connector according to the invention and the complementary insertion-type connector are pulled apart again, the first contact-making members  18  are pulled back again from the second position to the first position. There is preferably provided an appropriate first securing mechanism which only permits the first contact-making members  18  to move from the first position to the second position if the insertion-type connector according to the invention is fully inserted in the complementary insertion-type connector. It is also preferable for a second securing mechanism to be provided which prevents the insertion-type connector according to the invention and the complementary insertion-type connector from being unplugged from one another for as long as the first contact-making members  18  are not in the first position. 
     At its cable end  14 , the insertion-type connector according to the invention is connected to at least one electrically conductive cable. To decouple the movement of the first contact-making members  18  from the cable end  14 , or in other words from the cable, there is provided for each movable first contact-making member  18  the respective second contact-making member  20  which is fixed relative to the housing  10 , as shown in  FIGS. 3 to 5 . For reasons of clearer clarity, only one pair of first and second contact-making members  18 ,  20  is shown in each of  FIGS. 3 to 5 . 
     The first contact-making member  18  and second contact-making member  20  making up a pair are each of a blade-like form and the first and second contact-making members  18 ,  20  in each pair are arranged parallel to one another in such a way that respective wide sides  28  of the first and second contact-making members  18 ,  20  are adjacent one another. Also, at least one helical spring  32  made of an electrically conductive and resilient material is arranged, in a region of overlap  30  ( FIGS. 4 and 5 ), between the blade-like contact-making members  18 ,  20  which form a pair of first and second contact-making members  18 ,  20 . The diameter of the helical spring  32  in the region of overlap  30  and a distance, in this region of overlap  30 , between the blade-like contact-making members  18 ,  20 , i.e. between the wide sides  28  of a pair of first and second contact-making members  18 ,  20 , are so selected that respective turns of the helix of the helical spring  32  rest against the first contact-making member  18  by a first radial outer side and against the second contact-making member  20  by a second outer side opposite from the first radial outer side, thus producing between the turns of the helical spring  32  and the respective contact-making members  18 ,  20 , a point where electrical contact is made with a contact surface by a contact-making pressure. The contact-making pressure sets itself by virtue of the fact that the turns of the helical spring  32  are deflected from respective rest positions relative to a longitudinal axis of the helical spring  32  or in other words are tilted relative to the longitudinal axis of the helical spring  32 . This is achieved by making the distance between the blade-like contact-making members  18 ,  20  forming a pair of first and second contact-making members  18 ,  20  smaller than the outside diameter of the helical spring  32 . 
     The helical spring  32  is fastened to the first contact-making member  18 , which means that the helical spring  32  moves with the first contact-making member  18 . When there is a movement of the first contact-making member  18 , the turns of the helical spring  32  thus rub along the second contact-making member  20  and thereby maintain an adequate electrical connection between the two contact-making members  18 ,  20 . 
     The second contact-making members  20  each have a free end which has a terminal end-face  34 , this free end being adjacent the cable end  14  of the insertion-type connector according to the invention. The terminal end-face  34  is used for example to make electrical contact with a core or electrical conductor of a cable which is to be connected to the insertion-type connector according to the invention. 
     The helical spring  32  is preferably of an annular form and defines an area of space within its annulus. At the point in question and at its own boundaries relative to the helical spring  32 , this area is aligned parallel to the longitudinal axis of the helical spring  32 . Because of its annular form, in principle the helical spring  32  creates in space a torus which has two opposing axial ends. In accordance with the invention, the helical spring  32  is so arranged in the region of overlap  30  between the two contact-making members  18 ,  20  that the helical spring  32  butts against the first contact-making member  18  by turns at one axial end and against the second contact-making member  20  by turns at the other, opposite, axial end, as can be seen from  FIG. 3 . In other words, neither of the contact-making members  18 ,  20  fits through the area in the annulus of the annular helical spring  32  and instead the making of electrical contact between the helical spring  32  and the contact-making members  18 ,  20  takes place at axial ends of the annular helical spring  32 . Because of this the helical spring  32  can be securely fastened to the first contact-making member  18  and is secured against slipping or twisting if there is a movement of the first contact-making member  18  relative to the second contact-making member  20 . As can also be seen from  FIG. 3 , the area enclosed within the annulus of the helical spring  32  fits partly round the first contact-making member  18 . This provides additional assistance with the fixing of the helical spring  32  not only at the location of the first contact-making member  18  but also against any deformation of the annular form of the helical spring  32  between the contact-making members  18 ,  20 . 
     Because they are seen in section, the annular helical springs  32  are not shown in their entirety in  FIGS. 4 and 5 . The annulus, or rather the area defined within the annulus, fits round the first contact-making member  18  on the narrow side of the blade-like portion of the first contact-making member  18 . In the illustrative views shown in  FIGS. 4 and 5  four helical springs  32  are provided. It is however also possible for any other number to be provided in a region  30  where a pair  18 ,  20  overlap, such for example as one, two, three, five or six helical springs  32 . 
     While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.