Abstract:
In a contact element ( 10 ) for electrically connecting two contact pieces ( 13, 15, 16, 17 ) opposing each other with contact surfaces ( 18 ), wherein the contact element ( 10 ) extends along a longitudinal axis ( 19 ) and encompasses numerous separate, identical spring-mounted individual elements ( 12 ) that are arranged essentially parallel to each other and transverse to the longitudinal axis ( 19 ), which are secured to a continuous carrier band ( 11 ) extending in the direction of the longitudinal axis ( 19 ), and establish the electrical contact between the contact surfaces, a large working area is achieved while keeping current load capacity high by designing the individual elements as interlaced contact bridges ( 12 ).

Description:
TECHNICAL AREA 
     The present invention relates to the field of electrical contacts. It relates to a contact element according to the introductory clause to claim  1 . 
     Such a contact element, in which individual contact webs or contact plates are spring-mounted to a metal sheet band, is manufactured and sold by the applicant under the type designation “MC contact lamella LACu”, or is described in U.S. Pat. No. 4,456,325. 
     PRIOR ART 
     Lamellar contact elements or contact lamellae available primarily in two variants have proven themselves in the area of technology relating to electrical contacts for transmission of high currents. In one (single-piece) variant, the entire contact lamella is stamped out of a sheet strip, and molded in such a way as to yield a continuous row of individual contact webs projecting out of the sheet strip plane and sprung by torsion, which are interlinked by continuous lateral webs. If the contact webs are designed symmetrically to the longitudinal axis, the tolerance existing between two contact pieces that can still be bridged by the contact lamella depends on the width of the contact webs. The wider the webs twisted around their longitudinal axis, the higher the tolerance that can be bridged with them. Since the number of webs per length unit of contact lamella, and hence the number of contact points between the contact pieces, diminishes given an increasing width of the contact webs, the level of transmittable currents simultaneously decreases as the size of the bridgeable tolerance rises. To resolve this dilemma, it has already been suggested in the past (e.g., see EP-B1-0 520 950) that the contact webs be designed asymmetrically and interleaved in such a way that the bridgeable tolerance can be increased without having to change the number of webs per unit of length. 
     In the other variant as known from the production program of the applicant or publication cited at the outset, the functions of spring mounting and contacting are separated. Contact is established via individual, massive and electrically well conducting webs or plates (e.g., Cu or Ag), which are secured to a correspondingly stamped carrier band for purposes of fixation and spring mounting. Even though the functional separation of spring mounting and contacting and associated freedom in material selection in this variant enables an elevated flexibility in layout and simpler optimization of the contacting and resilience properties of the contact lamella, the previously used massive, essentially rectangular contact plates have made it impossible to arrive at higher bridgeable tolerances, and hence to expand the sphere of application of these contact lamellae, at a constant current transfer capacity. 
     DESCRIPTION OF THE INVENTION 
     Therefore, the object of the invention is to further develop a contact lamella consisting of a shared carrier band and numerous individual contact elements attached thereto in such a way that it allows a distinctly greater tolerance compensation without diminishing the current transfer capacity. 
     The object is achieved through, the entirety of features of the invention. The essence of the invention lies in the fact that individual elements are designed as interlaced contact bridges. Interlacing makes it possible to vary the effective width of the individual contact elements, and hence the bridgeable tolerance, within broad limits, without having to alter the periodicity or number per unit of length of the individual elements. Since the individual contact elements or contact bridges can be formed independently from the stamping of the carrier band, optimized geometries for the contact bridges can be realized in a simple manner. 
     A first preferred embodiment of the invention is characterized by the fact that the contact bridges are essentially V shaped with two free ends and a central bend lying in between, and that the free ends of the contact bridges are secured to the carrier band in such a way that their central bend lies at a predetermined height over the carrier band. In particular, the surface clamped by the V shaped contact bridges is inclined relative to the plane of the carrier band, and the carrier band is designed in such a way that the contact bridges attaché thereto can be resiliently moved toward the carrier band with their central bend. The V shaped bent bridges are easy to manufacture, and their central bend ensures a definite contacting. 
     The carrier band is preferably divided into individual band sections sequentially arranged in the direction of the longitudinal axis, wherein each band section is allocated a contact bridge, and each band section encompasses two spring-mounted arms that extend from a central web running in the central axis of the carrier band transverse to the longitudinal axis, whose two free ends are secured to the free ends of the accompanying contact bridges. This gives rise to particularly good resilience properties. 
     A second preferred embodiment of the contact element according to the invention is characterized by the fact that the contact bridges each consist of a wire section, and that, for attaching a contact bridge to the carrier band, the free ends of the contact bridge are routed from one side through recesses in the carrier band and clamped with the carrier band by bending the ends projecting through the recesses to the other side. The advantage to this is that the contact lamella can consist of very simple elements that can be rigidly bonded together without any special additional means. 
     One alternatively preferred embodiment of the invention is characterized by the fact that the contact bridges are made out of parts stamped out of sheet steel, that, for attaching a contact bridge to the carrier band, the free ends of the contact bridges each have a clamping foot with which it is clamped to the accompanying spring-mounted arm, that the contact bridges are essentially flat stamped parts, that the spring-mounted arms can be turned around their longitudinal axis to incline the contact bridges relative to the plane of the carrier band, and that the contact bridges have an embossed area for purposes of stiffening in the area of the central bend. 
     It has proven beneficial to arrange the contact bridges in the direction of the longitudinal axis with a contact spacing of several millimeters, preferably 2-8 mm, and to have the deflection of the central bend in the direction of the longitudinal axis relative to the attachment points of the contact bridges to the carrier band with the contact bridges inclined measure several millimeters, preferably about 5-10 mm. 
     Additional embodiments are described in the subclaims. 
    
    
     BRIEF EXPLANATION OF FIGURES 
     The invention will be described in greater detail below based on embodiments in conjunction with the drawing. Shown on: 
     FIG. 1 is a preferred first embodiment of a contact element according to the invention, side view along the longitudinal axis; 
     FIG. 2 is the contact element from FIG. 1, side view transverse to the longitudinal axis; 
     FIG. 3 is the contact element from FIG. 1, top views; 
     FIG. 4 is a perspective view of the contact element from FIG. 1; 
     FIG. 5 is a perspective view of the contact element according to FIG. 1 inserted into a dovetailed puncture; 
     FIG. 6 is the incorporation of a (ring-shaped) contact element according to FIG. 1 on a plug; 
     FIG. 7 is the incorporation of a (ring-shaped) contact element according to FIG. 1 on a socket; and 
     FIGS. 8-11 is a second preferred embodiment of a contact element according to the invention, depictions comparable to FIGS.  1 - 4 . 
    
    
     WAYS FOR IMPLEMENTING THE INVENTION 
     FIGS. 1 to  4  show a first preferred embodiment for a contact element (contact lamella) according to the invention in different views (side view, top view, perspective view). The contact element  10  consists of a carrier band  11  made out of stamped sheet steel with good resilience properties and numerous V-shaped, bent contact bridges  12 , which are each bent from a piece of electrically readily conductive, mechanically stable wire comprised of a metal or metal alloy, i.e., a wire section  120 . The carrier band  11  is divided into a central web  110  running in the direction of the longitudinal axis  19  and numerous band sections  111  with parallel spring-mounted arm pairs  112 ,  113 , which extend to the outside in the band section  111  to either side of the central web  110 , perpendicular to the latter. Each pair of spring-mounted arms  112 ,  113  is allocated to one of the contact bridges  12 . 
     Each of the V-shaped bent contact bridges  12  has a central bend  121  in the form of a kink. The free ends of the wire section  120  are routed down through the corresponding recesses  116 ,  117  in the end areas of the spring-mounted arm pairs  112 ,  113  and bent to the inside, so that they run parallel to the carrier band  11  there as clamping feet  122 ,  123 . At the same time, the corresponding section of the contact bridge  12  is pressed on the carrier band  11  on the top of the carrier band  11 , so that the contact bridge is reliably and permanently press molded to the carrier band  11  or spring-mounted arms of the respective spring-mounted arm pair  112 ,  113 . This simultaneously ensures that the currents to be relayed from the contact element  10  are routed exclusively through the contact bridge  12 , namely from the central bend  121  to the clamping feet  122 ,  123  or vice versa. The recesses  116 ,  117  can take the form of holes in the spring-mounted arms  112 ,  113 . However, it is especially favorable for the automatic production of contact elements  10  if the recesses  116 ,  117 , as shown on the figures, are designed as depressions into which the contact bridges  12  can be inserted from the side. 
     The contact bridges  12  are interlaced on the carrier band  11 , and their free ends are attached to the carrier band  11  in such a way that their central bend  121  lies at a predetermined height over the carrier band  11 . The surface clamped by the V-shaped contact bridges  12  is here oriented at an angle of inclination diagonal to the plane of the carrier band  11 . The height of the central bend  121  over the carrier band  11  as determined by the angle of inclination and length of the wire section  120  is critical for the tolerance between two contact pieces maximally bridgeable by the contact element  10 . The inclined contact bridges  12  attached to the carrier band  11  can be resiliently moved toward the carrier band  11  with their central bend  121  during use primarily because the accompanying spring-mounted arms  112 ,  113  turn around their longitudinal axis during such a movement, and act as torsion springs. 
     To enable the transfer of sufficiently high currents via the contact element  10  in practice, it has proven beneficial to arrange the contact bridges  12  in the direction of the longitudinal axis  19  with a contact spacing a (FIG. 3) of several millimeters, preferably 2-8 mm. 
     As already mentioned, the length of the contact bridges  12  can be adapted to the requirements at the work location (tolerance to be bridged) within broad limits. However, it has proven beneficial in practice for inclined contact bridges  12  to have the deflection b (FIG. 3) of the central bend  121  in the direction of the longitudinal axis  19  relative to the attachment points of the contact bridges  12  on the carrier  11  measure several millimeters, preferably about 5-10 mm. 
     The contact elements  10  are preferably incorporated into a (flat) contact piece  13  or a (round) plug  15  or (round) socket  17  in the manner shown on FIGS. 5 to  7 . A puncture  14  with dovetailed cross-sectional profile is provided in the respective contact piece  13  (or  15 ,  17 ), into which the contact element  10  is inserted or pushed. To guide the contact element  10  into the puncture  14 , the free ends of the spring-mounted arms  112 ,  113  preferably have guide brackets ( 114 ,  115 ) bent at a right angle (FIG.  3 ). The floor of the puncture  14  then forms the one contact surface  18  on which the contact bridges  12  rest with their clamping feet  122 ,  123  (FIG.  4 ). The opposing (not shown) contact surface is contacted by the central bends  121 . In the case of a round plug  15  (FIG.  6 ), the contact element  10  forms a ring. The same applies to a plug contact made of a plug  16  and socket  17  (FIG.  7 ), in which the contact element  10  is inserted into the socket  17  with the central bends  121  directed inward. 
     FIGS. 8 to  11  present pictures of a second preferred embodiment for a contact element according to the invention that are comparable to FIGS. 1 to  4 . The contact element  20  again consists of a carrier band  21  made out of stamped sheet steel with good resilience properties and numerous V-shaped, bent contact bridges  22 . The contact bridges  22  are now stamped out of sheet steel consisting of an electrically readily conductive, mechanically stable metal or metal alloy. The carrier band  21  is also divided into a central web  210  running in the direction of the longitudinal axis and numerous band sections  211  with parallel spring-mounted arm pairs  212 ,  213 , which extend outwardly to either side of the central web  210 , perpendicularly to the latter. Each pair of spring-mounted arms  212 ,  213  is allocated to one of the contact bridges  22 . Guide brackets  214 ,  215  are located adjacent the spring-mounted arms  212 ,  213 . 
     Each of the V-shaped stamped contact bridges  22  has a central bend  221 . The free ends of the contact bridge  22  has clamping feet  222 ,  223 , with which the contact bridge  22  is reliably and permanently clamped to the spring-mounted arms  212 ,  213  of the accompanying band section  211 . 
     In this embodiment as well, the contact bridges  22  are interlaced according to the invention on the carrier band  21 , wherein their central bend  221  is located at a predetermined height over the carrier band  21 . The surface clamped by the V-shaped contact bridges  22  is here oriented at an angle of inclination diagonal to the plane of the carrier band  21 . Since the contact bridges  22  are essentially flat stamped parts, the spring-mounted arms  212 ,  213  are turned around their longitudinal axis (twisted) to incline the contact bridge  22  relative to the plane of the carrier band  21 . For stiffening purposes, the contact bridges  22  each have an embossed area  224  near the central bend  221 , which results in the area being slightly bent toward the top, as readily visible on FIG.  9 . At the same time, this ensures that the electrical contact in the area of the central bend  221  remains defined and largely punctiform, even if the contact bridges  22  are spring-mounted more tightly. 
     In sum, the new contact element is characterized by the following characteristics and advantages: 
     It yields a larger working area for bridging large tolerances and angular deviations; 
     The working area can be enlarged even further by lengthening the lever arm on the contact bridge; 
     The interlaced arrangement of the contact bridges makes it possible to achieve a low contact spacing, and hence a high current load capacity; 
     The incorporation width is low, because the hinges of the torsion-stressed spring-mounted arms lie in the middle of the contact element; 
     A minimal incorporation space (puncture depth) is required; 
     The separation of spring and contact function yields good resilience properties; 
     The sliding properties are uniformly low; 
     Good contacting is achieved via the contact bridges despite a relatively long current path; 
     A defined 3 point contacting comes about (2 contact points below, 1 contact point above); 
     The contact element can be used both as a plug or socket lamella (in various diameters) and for flat installation. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 REFERENCE NUMBER LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  10, 20 
                 Contact element 
               
               
                   
                  11, 21 
                 Carrier band 
               
               
                   
                  12, 22 
                 Contact bridge 
               
               
                   
                  13 
                 Contact piece 
               
               
                   
                  14 
                 Puncture 
               
               
                   
                  15, 16 
                 Plug 
               
               
                   
                  17 
                 Socket 
               
               
                   
                  18 
                 Contact surface 
               
               
                   
                  19 
                 Longitudinal axis 
               
               
                   
                 110, 210 
                 Central web 
               
               
                   
                 111, 211 
                 Band section 
               
               
                   
                 112, 113 
                 Spring-mounted arm 
               
               
                   
                 114, 115 
                 Guide bracket 
               
               
                   
                 116, 117 
                 Recess 
               
               
                   
                 120 
                 Wire section 
               
               
                   
                 121, 221 
                 Central bend (kink) 
               
               
                   
                 122, 123 
                 Clamping foot 
               
               
                   
                 212, 213 
                 Spring-mounted arm 
               
               
                   
                 214, 215 
                 Guide bracket 
               
               
                   
                 222, 223 
                 Clamping foot 
               
               
                   
                 224 
                 Embossed area 
               
               
                   
                 a 
                 Contact spacing 
               
               
                   
                 b 
                 Deflection