Abstract:
A coupling device having a first coupling part  3  provided with at least one projecting region, the regions of the first coupling part which project in the z direction being arranged eccentrically or centrally, and the projecting regions having conical outer surfaces formed with at least one angle relative to the z direction, the elastic regions  4  pointing in the direction of the centre being formed in a radially parallel manner within the second coupling part  3 . The the projecting regions of the first coupling part engage in the elastic regions  4  of the second coupling part  3  for the x-y orientation in the z direction. The second coupling part  3  is of one-piece design and can be produced in one operation.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to a coupling device having a first coupling part provided with at least one projecting region and a second coupling part provided with at least one elastic region.  
         [0002]     European Patent Application EP 0 255 042 discloses a clamping device for a tool on a machine tool, in particular for a die-sinking electrical-discharge machine. Described is a clamping device for a tool on a machine tool, in particular a die-sinking electrical-discharge machine, having a chuck which has two strips which project from the underside of the chuck and are provided with bearing surfaces for orienting the tool in an x direction and a y direction which point transversely to the centre line of the chuck. Provision is made for a plurality of posts to project from the underside of the chuck, said posts having reference surfaces, extending in the x-y plane, at their free end faces, the strips being formed eccentrically and at an angle relative to one another, and for a tool holder for bearing against the posts to have a plane surface in which two pairs of grooves are cut which are aligned with the strips and have elastic lips intended for bearing against the strips, the tool holder having a centre bore with locking elements for receiving a draw bolt in a locking and releasable manner.  
         [0003]     The object of the present invention is to provide a coupling device which can be produced automatically and cost-effectively in one operation. Furthermore, the coupling device is to have optimum rigidity, loading capacity, force distribution and a low overall height.  
       SUMMARY OF THE INVENTION  
       [0004]     The object is achieved according to the invention wherein the regions ( 2 ,  2 ′) of the first coupling part ( 1 ,  1 ′,  35 ,  42 ,  43 ,  44 ,  45 ,  46 ,  51 ) which project in the z direction are arranged eccentrically or centrally, and the projecting regions ( 2 ,  2 ′) have conical outer surfaces ( 6 ) formed with at least one angle ( 12 ,  12 ′) relative to the z direction, in that the elastic regions ( 4 ) pointing in the direction of the centre are formed in a radially parallel manner within the second coupling part ( 3 ,  25 ,  26 ,  32 ,  33 ,  34 ,  41 ,  47 ,  49 ), the projecting regions ( 2 ,  2 ′) of the first coupling part ( 1 ,  1 ′,  35 ,  42 ,  43 ,  44 ,  45 ,  46 ,  51 ) engaging in the elastic regions ( 4 ) of the second coupling part ( 3 ,  25 ,  26 ,  32 ,  33 ,  34 ,  41 ,  47 ,  49 ) for the x-y orientation in the z direction, in that the second coupling part ( 3 ,  25 ,  26 ,  32 ,  33 ,  34 ,  41 ,  47 ,  49 ) is of one-piece design, and in that the workpiece ( 16 ) or the tool, the first coupling part ( 1 ,  1 ′,  35 ,  42 ,  43 ,  44 ,  45 ,  46 ,  51 ) and the second coupling part ( 3 ,  25 ,  26 ,  32 ,  33 ,  34 ,  41 ,  47 ,  49 ) can be connected by means of a fastening device ( 53 ).  
         [0005]     The second coupling part of the coupling device according to the invention proves to be capable of being produced in one operation. It can be produced in one step on a lathe or milling machine. The production costs of the coupling device according to the invention are thus considerably reduced compared with the production costs of the coupling devices of the prior art. The second coupling part has many uses, so that only a few embodiments are necessary. The storage costs are therefore reduced. The coupling device according to the invention permits high-load applications. The risk of fracture is minimized. The coupling device can be produced and also used in a simple manner with both off-centre and central reference features.  
         [0006]     The second coupling part may be of square design with a circular or square opening.  
         [0007]     Depending on the desired application, the outer circumference of the second coupling part is circular or rectangular, preferably square. Likewise, the inner region of the second coupling part may be circular or rectangular, preferably square.  
         [0008]     According to a further embodiment, the first coupling part can have a conically shaped, projecting, centrally arranged region, and the elastic regions of the second coupling part can interact with the centrally projecting region of the first coupling part.  
         [0009]     The elastic regions of the second coupling part are preferably designed as circular sector sections, as circular sector sections with tongues, or in a tongue shape. These circular and/or tongue-shaped elastic regions can be produced in a simple manner on a lathe or milling machine.  
         [0010]     The coupling device according to the invention may be produced from conventional steel, the steel being hardened by a thermal ageing process.  
         [0011]     Furthermore, coupling devices can be made of aluminium or plastic.  
         [0012]     In a known manner, the coupling device according to the invention has a fastening device for fastening the second coupling part to the first coupling part. All fastening devices known in the prior art are conceivable, such as, for example, a bayonet fastener, screwing by means of a central screwed connection, etc.  
         [0013]     According to a preferred embodiment, the elastic regions are profiled and may additionally have a recess in the radial direction opposed to the centre of the second coupling part. This feature results in higher strength and loading capacity in the clamped state.  
         [0014]     In a corresponding manner, the elastic regions may have different thicknesses in the radial direction in order to increase the strength and the loading capacity of the coupling device.  
         [0015]     The arrangement of a web at the elastic regions in the direction of the centre of the second coupling part can preferably increase the strength and loading capacity of the coupling device.  
         [0016]     A further preferred embodiment of the coupling device consists in the fact that at least two second concentric coupling devices having different circumferential radii are arranged one inside the other. That is to say the coupling device can be used on two sizes. For example, the inner second coupling part may be provided with a central cone, and the outer second coupling part may be provided with four off-centre bars. Likewise, the inner second coupling part may have off-centre bars.  
         [0017]     Apart from that, the coupling device according to the invention may be constructed the other way round, i.e. the first coupling part has the elastic regions which interact with the projecting regions on the second coupling part.  
         [0018]     The coupling device according to the invention can be used in connection with pallets.  
         [0019]     The advantages associated with the coupling device are achieved in particular by the elastic regions of the second coupling part being arranged within the annular body of the second coupling part and not above it as in the prior art. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The invention is described below with reference to exemplary embodiments. In the drawings:  
         [0021]      FIG. 1  shows a three-dimensional illustration of the second coupling part,  
         [0022]      FIGS. 2   a  and  b  show the second coupling part in plan view and sectional view A-A,  
         [0023]     FIGS.  3  to  8  show various embodiments of the second-coupling part,  
         [0024]      FIGS. 9   a  and  b  show a two-piece embodiment of the second coupling part,  
         [0025]      FIGS. 10   a  and  10   b  show the first coupling part matching  FIG. 9 ,  
         [0026]      FIGS. 11   a  and  b  show sectional illustrations of the first coupling part of  FIG. 10 ,  
         [0027]      FIGS. 12   a, b  and  c  show a coupling device of low overall height,  
         [0028]      FIGS. 13   a  and  b  show a second coupling part with bars and cone,  
         [0029]     FIGS.  14  to  15  show applications of the coupling device in pallets. 
     
    
     DETAILED DESCRIPTION  
       [0030]     A three-dimensional view of the second coupling part  3  produced in one piece is shown from above and below in  FIG. 1 . In this exemplary embodiment, the second coupling part  3  is shown as a ring  5 . A square embodiment is likewise conceivable. The second coupling part has elastic sector-shaped regions  4  which point inwards with respect to the annular region  5 . The annular region  5  and the elastic regions  4  form a surface  7  having the elastic lateral  10  and circular  11  marginal regions.  
         [0031]     The second coupling part  3  is shown in plan view and sectional view A-A in  FIGS. 2   a  and  2   b . It has elastic regions  4 . The elastic regions  4  are four segments having lateral  10  and circular  11  marginal regions.  
         [0032]     Two embodiments of the first coupling part  1  and  1 ′ are shown in section in  FIGS. 3   a  and  3   b .  FIG. 3   a  has bars as projecting regions  2 , and  FIG. 3   b  has a central cone as projecting region  2 ′.  
         [0033]     The first coupling part  1  can be connected together with the second coupling part, for example, to the workpiece  16 , tool  16 , etc., by means of a fastening device (not shown). All known fastening devices are conceivable, for example by means of bayonet fastener, restraining by means of balls, etc. Shown in  FIG. 2   b  a tapped hole  18  is provided, into which a screw (not shown) can be screwed for restraining the second coupling part together with the first coupling part.  
         [0034]     In the clamped state, the elastic lateral marginal regions  10  interact with the projecting bars  2  of the first coupling part  1  with respect to the x-y orientation. In the clamped state, the centrally arranged cone provided in the first coupling part  1 ′ touches the elastic circular marginal regions  11  in an orienting manner in the x-y plane.  
         [0035]     The z orientation is effected via the seating surfaces  6 , which touch the surface  7  in the clamped state.  
         [0036]     The first coupling part is shown once again in plan view and sectional view in two exemplary embodiments  1  and  1 ′ in  FIGS. 4   a  and  4   b . The first coupling part  1  with the bars  8  can be seen in  FIG. 4   a . A first coupling part  1 ′ with a central cone  9  is shown in  FIG. 4   b . Both first coupling parts  1 ,  1 ′ have seatings  6  for the z orientation. The surfaces of the bars  8  and of the cone  9  having two bevels with different angles  12  of slope can be seen in the enlarged individual illustrations I and II.  
         [0037]     Another embodiment of the first coupling part  1  or  1 ′ shows the elastic region  4  with a profile. The profile has an inclination  13  and a recess  14 , as can be seen in  FIGS. 5   b  and  c .  FIGS. 5   b  and  c  represent enlargements of the detail III in  FIG. 5   a ,  FIG. 5   b  showing the coupling device in the relaxed state and  FIG. 5   c  showing it in the clamped state. The broken line is intended to represent a bar  8  or a seating surface  6 . Before the coupling device is clamped, the inclined profile is in contact in a first step, the elastic element  4  orients the first coupling part  1 , and the inclination  13  is oriented parallel to the bar surface or to the seating surface. A recess  14  is preferably incorporated in the elastic region  4 . The recess  14  is provided above the contact surface. The advantage associated therewith means high rigidity, better loading and greater resistance to fracture. At higher loads, the elastic contact between the elastic regions  4  and the bar surfaces changes to firm contact with the recesses  14 . Further bending of the elastic regions is thus prevented. Fracture is prevented as a result.  
         [0038]      FIGS. 6   a  and  b  show a further embodiment of the first coupling part. The elastic regions  4  additionally have a web  15  at the region pointing towards the centre. The web  15  increases the rigidity. The web  15  forms a narrow gap  17  at the end pointing in the direction of the workpiece  16 . This preferred embodiment can be used in particular for coupling devices made of materials different from steel, such as, for example, aluminium, plastic, etc.  
         [0039]     Another embodiment of the elastic regions  4  can be seen in  FIGS. 7   a  and  7   b ,  FIG. 7   b  showing a sectional illustration of  FIG. 7   a  in direction C-C. The elastic regions  4  have tongue-shaped regions  19 . The advantage associated therewith consists in particular in an increase in the elasticity. Each tongue  19  can be deformed more effectively on its own.  
         [0040]      FIGS. 8   a  and  8   b  show a further configuration of the elastic regions.  FIG. 8   b  shows the section along line D-D. In contrast to the embodiment in  FIGS. 7   a  and  7   b , the annular part  5  has projections  20  below the elastic regions, and these projections  20  support the elastic regions, so that only the projecting tongue-shaped regions can be elastically deformed during the clamping, which results in greater accuracy.  
         [0041]     In  FIGS. 8   c  and  8   d  (section in direction D-D), the circular margin of the elastic regions  4  has a cutout  21 , i.e. the region between the tongues  19  is fixed. The result is in an elastic restraint in the contact region  22  during average loads with high accuracy. There is thus no firm contact in the region of the recess  23 . At an even higher load, the tongues  19  are bent further in the axial direction until firm contact with the surface  24  is obtained, whereby higher strength and resistance to fracture is obtained.  
         [0042]     FIGS.  9  to  11  show a coupling device having a two-piece second coupling part  25  and  26  and the associated first coupling part  32  and  33 . The second coupling part in  FIG. 9   a  and in the sectional illustration according to  FIG. 9   b  can consist of at least two second coupling parts  25  and  26 , the inner coupling part  25  being arranged concentrically in the outer coupling part  26 . Due to the two-piece configuration, various embodiments described above can be combined, depending on the existing boundary conditions. That is to say coupling devices are possible in which the elastic regions  4  with respect to the inner coupling part  25  may differ from the elastic regions  4  of the outer coupling part  26 .  
         [0043]     The coupling devices having the two second coupling parts  25  and  26  and the associated first coupling parts  32  and  33  are shown in FIGS.  9  to  11 . They are of similar construction to the one-piece first coupling parts in the previous figures. Reference numerals  27  signify the outer bars,  28  the inner bars,  29  the central cone,  30  the inner z seatings and  31  the outer z seatings.  
         [0044]     A coupling device of smaller diameter is shown in  FIGS. 12   a  to  12   c . The second coupling part  34  in  FIG. 12   a  and in the sectional drawing G-G in  FIG. 12   b  has recesses  38  between the elastic regions  4 . The recesses  38  provide space for the z seatings  37  of the first coupling part  35  in  FIG. 12   c.    
         [0045]     A combination of bars  39  and central cone  40  is shown in the second coupling part  41  in  FIGS. 13   a  and  13   b . This combination can be used in the case of pallets with individual holders or multi-holders. The combination shown in  FIGS. 13   a  and  b  can then be used advantageously in a space-saving manner.  
         [0046]     An application for pallets is shown in  FIGS. 14   a  and  b . Four first coupling parts  42  can be seen, the first coupling part  43  in  FIG. 14   a  being provided for x-y-z orientation, the first coupling part  44  being provided for x-z orientation, the first coupling part  45  being provided for y-z orientation and the first coupling part  46  being provided for z orientation. For all applications, the second coupling part  47  is disclosed in a single embodiment in  FIG. 14   b.    
         [0047]      FIGS. 15   a  and  b  show a further application of the coupling device. Here, in particular the low overall height of the coupling device is to be emphasized, which is required in wire electrical-discharge machines for example. The first coupling part  49  is fastened to the base  48  of the wire electrical-discharge machine. The second coupling part  51  is connected to the workpiece  52 , the bottom surface  54  of the workpiece  52  lying with the base surface  54  of the wire electrical-discharge machine at the level of the 0 line  50 .  
         [0048]     Of course, the first coupling part and the second coupling part can be used the other way round for all the embodiments described above, i.e. the first coupling part has elastic regions and the second coupling part has projecting regions.