Abstract:
A contact element for connecting to a cable having a braided shield includes a spring contact sleeve and a crimp sleeve. The spring contact sleeve has an annular ring and spring contacts arranged circumferentially on one end of the annular ring. The spring contact sleeve and the crimp sleeve form an enclosed hollow cavity between one another when the crimp sleeve is joined to the annular ring. The hollow cavity is configured to fully receive therein an exposed portion of the braided shield provided for connection of the contact element to the cable.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/EP2014/060993, published in German, with an International filing date of May 27, 2014, which claims priority to DE 10 2013 009 184.5, filed May 31, 2013; the disclosures of which are hereby incorporated in their entirety by reference herein. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a contact element for making a shield connection to a cable provided with a braided shield, the contact element including (i) a spring contact sleeve having an annular ring and spring contacts connected circumferentially to the annular ring and (ii) a crimp sleeve that can be connected to the annular ring. 
     BACKGROUND 
     DE 10 2011 102 566 A1 describes a contact element having a spring contact sleeve and a crimp sleeve. The spring contact sleeve has an annular ring and spring contacts arranged circumferentially on the annular ring. Each spring contact is respectively formed of a substantially linear supporting arm. The supporting arm of each spring contact is connected to a respective spring arm through a U-shaped curved section. 
     The connection of the contact element to a braided cable is accomplished by pushing the spring contact sleeve onto the cable sheath of the cable whereby the supporting arms rest against the cable sheath. Since a fixed connection has not yet been achieved, the spring contact sleeve can be rotated and moved into a desired position on the cable sheath. The braided shield of the cable is folded back in such a manner that the braided shield contacts the supporting arms to complete the connection to the braided shield. In a subsequent assembly step the crimp sleeve is pushed over the supporting arms so that the crimp sleeve surrounds the braided shield from the outside. The crimp sleeve is then pressed together with the supporting arms and the braided shield located between them. 
     A disadvantage of this contact element is the relatively elaborate design that is required to bend the supporting arms and the spring arms. A particular drawback is that the crimp sleeve, which is cylindrical shaped, cannot completely enclose the braided shield from all sides. This is disadvantageous for high voltage contacts since individual loose braided shield strands, which can result from stripping the cable, and exposure of the braided shield can cause dangerous short circuits. 
     SUMMARY 
     An object is a contact element that is characterized by a relatively simple and cost-effective design and is relatively simple to assemble to a cable having cable shielding and can produce a safe electrically shielded connection. 
     In carrying out at least one of the above and/or other objects, a contact element for connecting to a cable having a braided shield is provided. The contact element includes a spring contact sleeve and a crimp sleeve. The spring contact sleeve has an annular ring and spring contacts arranged circumferentially on one end of the annular ring. The spring contact sleeve and the crimp sleeve form an enclosed hollow cavity between one another when the crimp sleeve is joined to the annular ring. The hollow cavity is configured to fully receive therein an exposed portion of the braided shield provided for connection of the contact element to the cable. 
     Further, in carrying out at least one of the above and/or other objects, a cable assembly is provided. The cable assembly includes a cable and a contact element. The cable has a braided shield. The contact element has a spring contact sleeve and a crimp sleeve. The spring contact sleeve has an annular ring and spring contacts arranged circumferentially on one end of the annular ring. The spring contact sleeve and the crimp sleeve form an enclosed hollow cavity between one another when the crimp sleeve is joined to the annular ring. The spring contact sleeve and the crimp sleeve are placed on the cable with the cable extending through aperture passages of the spring contact sleeve and the crimp sleeve and the crimp sleeve is joined to the annular ring to thereby form the enclosed hollow cavity between the spring contact sleeve and the crimp sleeve. The hollow cavity fully receives therein in a physical contact manner an exposed portion of the braided shield to thereby electrically connect the contact element to the cable. 
     An embodiment provides a contact element for contacting the cable shielding (e.g., braided shield) of a cable in a shielded manner. The contact element includes a spring contact sleeve and a crimp sleeve. The spring contact sleeve has an annular ring and spring contacts. The spring contacts are circumferentially arranged on one end of the annular ring. The spring contact sleeve and the crimp sleeve are placed on the cable with the cable extending through aperture passages of the spring contact sleeve and the crimp sleeve. The spring contact sleeve and the crimp sleeve form a hollow cavity (i.e., receptacle chamber) between one another when the crimp sleeve is joined to the spring contact sleeve. The hollow cavity is enclosed by the spring contact sleeve and the crimp sleeve. The hollow cavity can completely accommodate therein an exposed portion of the braided shield. The exposed portion of the braided shielded accommodated within the cavity is in physical contact with the spring contact sleeve and the crimp sleeve thereby contacting the contact element and the cable together in a shielded manner. 
     In embodiments, the spring contact sleeve and the crimp sleeve form a hollow cavity when joined together. The hollow cavity is formed between the spring contact sleeve and the crimp sleeve. An exposed section of the braided shield of the cable, which is provided for the connection of the cable to the contact element, is accommodated within the hollow cavity. That is, the hollow cavity completely encloses in a physical contacting manner the exposed section of the braided shield thereby connecting the contact element and the braided shield of the cable together. 
     In embodiments, the crimp sleeve is in the shape of a cap. The cap includes a base plate having a circularly shaped aperture passage extending therethrough. The crimp sleeve is pushed onto the cable with the cable extending through the aperture passage of the crimp sleeve. The diameter of the aperture passage of the crimp sleeve corresponds closely to the outer dimension of the inner insulation of the cable. Thus, the crimp sleeve tightly seals to the portion of the cable extending through the aperture passage of the crimp sleeve. That is, the crimp sleeve tightly seals to the inner insulation of this portion of the cable. 
     Because of the complete enclosure of the stripped braided shield of the cable within a receptacle chamber formed by the hollow cavity and a part of the crimp sleeve that surrounds it and the spring contact sleeve, no loose sections of the braided shield can move around and give rise to short circuits. This is advantageous when the conductor contact is made to a high voltage cable carrying high currents and voltages, as for example in an electric vehicle. 
     In embodiments, the crimp sleeve has an integrally molded structured (i.e., gripping) inner contour on its inner surfaces. The inner contour can be designed, for example, as a spiral, helix, diamond shaped, or corrugated pattern. The gripping inner contour enables the braided shield of the cable to be pulled completely under the crimp sleeve with rotational movements while the crimp sleeve is being attached to the spring contact sleeve. The stripped sections of the braided shield are thereby completely enclosed in the hollow cavity formed by the spring contact sleeve and the crimp sleeve. 
     In embodiments, the spring contact sleeve assumes a relatively simple shape that does not require U-shaped bending of the spring contacts of the spring contact sleeve. The spring contact sleeve can thus be manufactured in a relatively simple and cost-effective manner as a single molded part, in particular through a thermoforming process. 
     In embodiments, the spring contacts of the spring contact sleeve are a cover surface whose free end sections extend away from the annular ring of the spring contact sleeve. The spring contacts can form an ascending section with respect to the axis of symmetry of the spring contact sleeve and an adjoining section that is parallel to the axis of symmetry or at least ascends noticeably less steeply. The ascending sections deflect when a cylindrically shaped section of a metal housing is pushed over the spring contact sleeve. The parallel or slightly ascending sections, possibly using integrally molded contact points, lie against the inner surface of the metal housing and thereby produce well-defined contact junctions making a good electrical connection. 
     In embodiments, the annular ring of the spring contact sleeve has an uninterrupted annular surface. As a result of this an increase in stability is achieved as compared to an interrupted lamellar structure, especially for the attachment of the crimp sleeve. 
     In embodiments, the annular ring of the spring contact sleeve has a collar on its end section. (The spring contacts are arranged on the other end section of the annular ring.) The diameter of the collar is smaller than the inner diameter of the spring contact sleeve. The inner diameter of the spring contact sleeve is determined so that the spring contact sleeve rests snugly on the exterior cable sheath when the spring contact sleeve is pushed over the cable. The collar of the annular ring thereby strikes the front edge of the cable sheath, which is formed as a result of a portion of the cable sheath being stripped off the cable. The collar thus determines the position of the spring contact sleeve on the cable. 
     In embodiments, the contact element can be used on a high voltage coaxial cable, for example in electrically powered motor vehicles or in energy supply systems that use regenerative energy sources. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a contact element having a spring contact sleeve and a crimp sleeve, the contact element being in a disassembled state in which the spring contact sleeve and the crimp sleeve are not joined together; 
         FIGS. 2, 3, 4, 5, 6, and 7  respectively illustrate steps in the assembly of the contact element on a shielded cable shown with each of  FIGS. 2, 3, 4, 5, 6, and 7  having a cross-sectional view a) and a plan view b); and 
         FIGS. 8 and 9  illustrate an application example of the shield connection of the contact element to the shielded cable. 
     
    
    
     DETAILED DESCRIPTION 
     Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Referring now to  FIG. 1 , a contact element for contacting braided shield  4  of a cable  5  (not shown in  FIG. 1 ) in a shielded manner is shown. The contact element includes a spring contact sleeve  1  and a crimp sleeve  6 . Spring contact sleeve  1  and crimp sleeve  6  can be joined together to form the assembled contact element. As shown in  FIG. 1 , the contact element is in a disassembled state in which spring contact sleeve  1  and crimp sleeve  6  are not joined together. 
     Spring contact sleeve  1  is a unitary molded component. Spring contact sleeve  1  includes an annular ring  3  and a plurality of flat surface spring contacts  2 . Spring contacts  2  are integrally molded circumferentially on an end section of annular ring. Spring contacts  2  form a lamellar crown that opens in a direction extending away from the end section of annular ring  3 . 
     Each spring contact  2  has a first spring contact portion  14 , a second spring contact portion  15 , and a contact point  23 . First spring contact portion  14  steeply ascends relative to the axis of symmetry of spring contact sleeve  1 . Second spring contact portion  15  is parallel to or ascends at a noticeably flatter rate to the axis of symmetry of spring contact sleeve  1 . The more steeply ascending first spring contact portions  14  deflect while being pushed radially inward by a cylindrically shaped socket section  18  of a metal housing  21  pushed over the assembled contact element (shown in  FIG. 9 ). The flatter second spring contact portions  15  lie against the inner surface of socket section  18  of metal housing  21  pushed over the assembled contact element (shown in  FIG. 9 ). Contact points  23  of spring contacts  2  are respectively integrally molded on second spring contact portions  15 . Contact points  23  provide well-defined contact junctions to metal housing  21  (shown in  FIG. 9 ). 
     Crimp sleeve  6  is formed as a cap having a base plate  8  and inner surfaces provided with a structured (e.g., gripping) inner contour  7 . Base plate  8  has a circularly shaped aperture passage  16  extending therethrough and bordered by inner contour  7 . 
     Referring now to  FIGS. 2, 3, 4, 5, 6, and 7 , with continual reference to  FIG. 1 , sequential steps in the assembly of the contact element on cable  5  are respectively shown. Each of  FIGS. 2, 3, 4, 5, 6, and 7  includes a cross-sectional view a) and a plan view b) of a respective assembly step. 
       FIGS. 2, 3, 4, 5, 6, and 7  clarify the mounting of the two-component contact element on cable  5 . Cable  5  has a cable shield formed as a braided shield  4 . Cable  5  is shown as a high-voltage coaxial cable. Such high-voltage coaxial cables  5  are used, for example, in electrically powered motor vehicles and carry both relatively high currents and voltages. 
     Cable  5  further has an inner conductor  9 , an inner insulation  11 , and an outer cable sheath  10 . Inner insulation  11  is between braided shield  4  and inner conductor  9  and lies beneath the braided shield. Cable sheath  10  lies above braided shield  4  and forms an exterior insulating layer of cable  5 . Inner conductor  9  is shown in  FIGS. 2, 3, 4, 5, 6, and 7  as a simplified solid object made of a plurality of individual strands in order to increase the flexibility of cable  5 . Braided shield  4  surrounding inner insulation  11  is primarily responsible for keeping interference radiation in cable  5  as small as possible. In this application it is important that while preparing cable  5  no part of inner conductor  9  or braided shield  4  is accessible, or that no leftover part remains, which could give rise to dangerous short circuits when detached from cable  5 . 
       FIG. 2  illustrates the first assembly step as the pushing of spring contact sleeve  1  onto a free cable  5  whose end section has already been stripped. Collar  13  of annular ring  3  of spring contact sleeve  1  constricts the aperture passage of the annular ring on the one end section of cable  5 . 
       FIG. 3  illustrates the second assembly step. As shown in  FIG. 3 , to further connect spring contact sleeve  1  to cable  5 , annular ring  3  of spring contact sleeve  1  is pushed onto cable  5  until collar  13  of annular ring  3  strikes the front edge of cable sheath  10 . Because of this an exact and secure positioning of spring contact element  1  with respect to cable  5  is obtained. 
     As further shown in  FIG. 3 , braided shield  4  and inner insulation  11  are cut to the same length. This length is chosen so that in the next sequential assembly step, shown in  FIG. 4 , the folding back of braided shield  4  in the direction of spring contact sleeve  1  is such that braided shield  4  covers annular ring  3  of spring contact sleeve  1 . 
     In the next sequential assembly step, shown in  FIG. 5 , crimp sleeve  6  is pushed over the free end of cable  5 . The cap-shaped crimp sleeve  6  has aperture  16  in its base plate  8 . The diameter of aperture  16  of crimp sleeve  6  corresponds as precisely as possible to the cross-section of cable  5  in the region of inner insulation  11  of cable  5 . The edge of aperture  16  of crimp sleeve  6  thereby lies tightly on inner insulation  11  of cable  5 . 
     In contrast, the open side of crimp sleeve  6  is wider than annular ring  3  of spring contact sleeve  1 . As a result, crimp sleeve  6  can be pushed over annular ring  3  and braided shield  4  that lies on it. 
     Pushing of crimp sleeve  6  onto cable  5  is accomplished by using a superimposed rotational motion. The inner surface of crimp sleeve  6  has integrally molded structured inner contour  7 . Inner contour  7  is designed as a screw like inner thread, as indicated to some extent in the figures. When crimp sleeve  6  is rotated, braided shield  4  is carried with crimp sleeve  6  by its inner contour  7  in the direction of motion and is pulled completely under crimp section  6 . 
     In the next sequential assembly step, shown in  FIG. 6 , crimp sleeve  6  is already partially pushed over annular ring  3  of spring contact sleeve  1 . Flared cams  12  on crimp sleeve  6  function as catches during the rotational motion for sections of wire of braided shield  4  protruding between crimp sleeve  6  and annular ring  3  of spring contact sleeve  1 . Crimp sleeve  6  is rotated until cams  12  insert into matching shaped wells  22  in annular ring  3  of spring contact sleeve  1  (shown in  FIG. 1 ). 
     The finished assembly, shown in  FIG. 7 , is hereby produced in which crimp sleeve  6  has arrived at its final position. In this final position, the leading edge of crimp sleeve  6  now rests against spring contact sleeve  1 . A hollow cavity  17  whose boundary walls completely encapsulate braided shield  4  remains because of its shape between crimp sleeve  6  and spring contact sleeve  1 . 
     Crimp sleeve  6  is then connected to spring contact sleeve  1  so that it cannot be released by a crimp (not shown). A secure mechanical and electrical connection is produced in this manner between braided shield  4  of cable  5  and spring contact sleeve  1 . 
     The arrangement described thus far can be supplemented by connecting to a screened plug-in connector. To this end, a socket contact  19  can be crimped to inner conductor  9  of cable  5 , as is shown in  FIG. 8 . Socket contact  19 , shown as an example in  FIGS. 8 and 9 , is provided to accommodate flat connector pins. To achieve a moisture-proof seal, a sealing gasket  20  can be attached to cable  5 . 
     The preassembled component is then inserted into a metal housing  21 , as shown in  FIG. 9  in a sectional view. Spring contacts  2  of spring contact sleeve  1  resting against the inside of socket section  18  produce an electrical connection between braided shield  4  of cable  5  and metal housing  21 . 
     REFERENCE SYMBOL LIST 
       1  spring contact sleeve 
       2  spring contacts of spring contact sleeve 
       3  annular ring of spring contact sleeve 
       4  braided shield of cable 
       5  cable (high-voltage coaxial cable) 
       6  crimp sleeve 
       7  inner contour of crimp sleeve 
       8  base plate of crimp sleeve 
       9  inner conductor of cable 
       10  cable sheath 
       11  inner insulation of cable 
       12  cams 
       13  collar 
       14  first portion of a spring contact 
       15  second portion of a spring contact 
       16  aperture passage 
       17  hollow cavity 
       18  socket section 
       19  socket contact 
       20  seal 
       21  metal housing 
       22  wells 
       23  contact point of a spring contact 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the present invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the present invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the present invention.