Abstract:
The present invention relates to a multi-axial joint ( 1 ), particularly for robotics. The multiaxial joint comprises a distal joint section ( 2 ) and a proximal joint section ( 4 ) that are pivotably and swivably connected relative to each other via at least one rotatory pivot joint ( 26 ) with a rotational axis ( P ) and at least one rotatory swivel joint ( 13 ) connected in series with the pivot joint ( 26 ) and having a swivel axis (R) extending perpendicular to the rotational axis (P). With such a multiaxial joint it is possible to realize two degrees of freedom. To achieve a compact constructional shape, the pivot joint ( 26 ) and the swivel joint ( 13 ) are united by being slid into each other to form a structural unit. The multiaxial joint ( 1 ) is particularly intended to enable an operation via traction means so as to simulate the movement of an animal or human joint. To absorb great forces, a forked ( 28 ) structure may be chosen.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a Divisional of and claims priority to U.S. application No. 12/761,964, filed Apr. 16, 2010 and the benefit of German Patent Application No. 102009017581.4, filed Apr. 18, 2009, the entire disclosures of which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention refers to a multiaxial joint, particularly for robotics, with a distal joint section and a proximal joint section that are pivotably and swivably connected relative to each other via at least one rotatory pivot joint with a rotational axis and at least one rotatory swivel joint connected in series with the pivot joint and having a swivel axis extending perpendicular to the rotational axis. 
       SUMMARY OF THE INVENTION 
       [0003]    Such a multiaxial joint permits a movement of the distal, freely movable joint section with respect to the proximal joint section, which is fixed relative thereto, in two degrees of freedom. The two joint sections serve to fasten the multiaxial joint and/or to mount further components, also further multiaxial joints. The joint sections may be pin-shaped or may be designed in the form of bushings or recesses and allow a form-fit or frictionally engaged connection. 
         [0004]    The pivot joint and the swivel joint are each separate rotatory joints, each permitting a purely rotatory movement about the corresponding axis, the rotational axis and the swivel axis. 
         [0005]    It is the object of the present invention to provide a multiaxial joint that is as compact as possible. 
         [0006]    This object is achieved according to the invention in a constructionally simple way for the aforementioned multiaxial joint in that the pivot joint and the swivel joint are united by being slid (positioned) into each other to form a structural unit. 
         [0007]    The sliding (positioning) of the swivel joint and of the pivot joint into each other creates a compact structural unit in which the one (pivot or swivel) joint surrounds the other (swivel or pivot) joint at least in sections. 
         [0008]    This compact structural shape can be further improved by the following additional features that can be combined with one another in any desired way. 
         [0009]    To simulate the kinematics of for instance a human elbow joint with the multiaxial joint according to the invention, it is e.g. of advantage when the swivel axis extends perpendicular to the connection line between the proximal and the distal joint section and the rotational axis in the direction of the distal joint section. Hence, the swivel axis enables the bending and stretching of the distal joint section relative to the proximal joint section, and the pivot joint a rotation or supination and pronation of the distal joint section relative to the proximal joint section. The distal joint section can be designed in this configuration particularly as a preferably multiply supported shaft, particularly as a hollow shaft. 
         [0010]    In a further advantageous design the swivel joint may comprise a forked section having at least two bearing elements for supporting the rotary bearing about the swivel axis so as to absorb torsional forces arising upon rotation of the distal joint section. To this end the bearing elements can particularly be spaced apart in the direction of the swivel axis of the swivel bearing. The swivable pivot joint extends between the two bearing elements. In this design the pivot joint is thus slid (positioned) between the bearing elements of the swivel joint. 
         [0011]    If the multiaxial joint is used as an active, dynamically operated joint so as to move e.g. loads, low-friction bearing forms, e.g. rolling bearings or sliding bearings, are preferably used. 
         [0012]    With a passive use of the multiaxial joint in the case of which the multiaxial joint is moved from the outside into a desired position the joint is then to maintain in a static way, bearings of high friction values may also be used. For a passive use also locking means may be integrated alternatively or additionally into the multiaxial joint for fixing the swivel joint and/or the pivot joint. Such locking devices may comprise brakes or latching (stop) means as well as tensioning and clamping elements. 
         [0013]    The desired compact structural shape can once again be reduced in size according to a further advantageous design if at least one bearing element of the swivel bearing is designed as a ring bearing which encloses the rotary bearing at least in sections. In this configuration the rotary bearing can substantially be accommodated within the swivel bearing. The diameter of the ring bearing corresponds at least almost entirely to the diameter of the rotary bearing in the area of the ring bearing. With adequately large dimensions of the ring bearings the ring bearings can be made from plastics without impairment of the bearing load due to the lower surface pressure. To achieve a particularly compact structural shape, the pivot joint can extend in a further design through the plane formed by the ring bearing. 
         [0014]    The use of large and correspondingly stable ring bearings gives the multiaxial joint a great strength, especially if the ring bearings are combined with the forked design of the swivel joint and the ring bearings enclose the pivot joint in the direction of the swivel axis at both sides. Such a forked design of the ring bearings is e.g. known in the field of castors and permits high bearing loads despite the use of inexpensive plastic materials for the elements of the ring bearing. 
         [0015]    The multiaxial joint may e.g. have the approximate shape of a ball or sphere and e.g. comprise a housing which is preferably shaped as a hollow ball and encloses at least the pivot joint in the manner of a shell or capsule. A housing of such a configuration gives the multiaxial joint additional strength because it acts as a shell-type supporting structure. The spherical shape results in a strain distribution inside the housing that is optimal in terms of strength, so that great forces can be absorbed at small wall thicknesses. Moreover, the enclosed pivot joint is protected by the housing against contamination. 
         [0016]    Irrespective of its shape, the housing may be part of the distal section or part of the proximal section of the pivot joint. In the first case the shell-shaped housing is supported relative to the proximal joint section in the bearing elements of the swivel joint to rotate about the swivel axis. In the last case the housing is fixed with respect to the proximal joint section, and at least a recess must be provided in the housing for the swivel movement of the distal joint section, or the swivel joint is accommodated in the pivot joint. 
         [0017]    For exact movement guidance without the need for compensatory movements, it is of advantage when the rotational axis of the pivot joint and the swivel axis of the swivel joint intersect each other. This measure ensures that the rotational axis always extends radially relative to the swivel axis. 
         [0018]    It is of special advantage with respect to the use of the multiaxial joint according to the invention in robotics when the pivot joint and/or the swivel joint, preferably both, are configured to be drivable by traction means that are operable outside the joint. The traction means and the actuators acting on the traction means can also be part of the multiaxial joint according to the invention or of a joint assembly with at least one such multiaxial joint. Such traction means encompass e.g. wires, Bowden cables, belts, toothed belts and/or chains. The use of traction means permits an operation of the multiaxial joint simulating human or animal joints, the traction means assuming the functions of tendons. When the traction means cannot transmit compressive forces, two traction means acting against each other should be provided for each joint so as to drive the joint in both rotational directions. The actuators connected to these two traction means conform to the agonist and the antagonist of a biological muscle-joint system. As an alternative, and instead of the one traction means, a spring element may also be provided, against which the remaining traction means works and which effects an automatic return movement of the force-free joint into a resting position. 
         [0019]    In contrast to the force transmission by means of push rods or torsion elements, which must be made comparatively massive, the use of mechanical traction means for the transmission of the driving and actuating forces generated by the actuators makes it possible to save a lot of weight and to achieve a much more advantageous mass distribution at the same time. Since traction means can transmit very great forces, but since their length is of no great significance for their weight, the actuators can be arranged far away from the joints. As a result, this imparts great freedom in terms of design for the use of the multiaxial joint, and the moved masses in the distal movable portions of the construction can be kept small. This, in turn, results in a very good mass/performance ratio, which allows rapid movements with high accelerations. At the same time the risk of injury and destruction in cases of collisions can be reduced in an advantageous way due to the small mass moved. 
         [0020]    Furthermore, the traction means and/or the actuators can, in a comparatively easy way, be given elastic properties and/or be held by spring-elastic tensioning elements, resulting in high resistance to shock. With such a design particularly soft and flexible motion sequences that are close to those of their natural examples can be realized. 
         [0021]    For use with traction means the pivot joint and/or the swivel joint can particularly comprise at least one drive member with at least one holding element for a traction means. The drive member can e.g. be designed in the form of cam- or disc-shaped sections of the pivot joint and/or the swivel joint. The holding element serves to establish a force closure (non-positive connection) between the part that is moved by the traction means and belongs to the respective joint, and the traction means, thereby transmitting the drive force from the traction means to the drive member and the distal joint section. The holding element can be configured as a fastening means for the end of the respective traction means and/or as a guide section around which the traction means is winding or wound. For the drive member of the pivot joint to move only slightly in the event of a long swivel movement, it is advantageously arranged at least close to the swivel axis, with the rotational axis intersecting the swivel axis at least close to the point of section. 
         [0022]    With a cam-shaped design of the drive member the radius on which the traction means introduces the force of movement into the joint is changing through the movement of the respective joint. Thus, the movement force or the movement speed, respectively, can be changed, in conformity with the cam shape, predeterminedly depending on the current position of the respective joint. 
         [0023]    By contrast, with a disc-shaped design of the drive member the radius remains constant in all movement phases. The drive member can be provided with a support portion for the traction means, on which portion the traction means comes to rest during movement and is wound, respectively. 
         [0024]    The cam shape or disc shape is accomplished through a corresponding design of the support portion on which the traction means winds around the drive member. Furthermore, the support portion can be used for winding up the traction means when movements of more than 360° are to be generated by means of two traction means counteracting each other. The winding off of a complete winding results in a movement of 360° in each joint. If several windings are wound, multiple revolutions of the joint can be achieved. 
         [0025]    If the traction means is wound as a preferably endless loop around the drive member, a simple rotational drive can be used as the actuator; as has been mentioned above, this drive can be arranged at any desired place outside the multiaxial joint and drives the traction means via a roll. 
         [0026]    Furthermore, the use of traction means permits a simple manual remote control. For instance, the traction means can be moved in the manner of puppets by an operator&#39;s body in that they are connected to the operator&#39;s arm and transmit the arm movement to the movement of the multiaxial joint. 
         [0027]    In a further design the drive member of the pivot joint may be integrally connected to the distal joint section and e.g. be configured as an integral section of a rotational shaft of the distal joint section. 
         [0028]    The respective traction means can be guided from outside of the multiaxial joint to the respective pivot and/or swivel joint, thereby passing through the possibly existing housing. Alternatively, the traction means can also be guided inside the multiaxial joint, e.g. through proximal and/or distal joint sections of a hollow configuration, to the respective pivot and/or swivel joint. In both instances standardized fastening means and/or coupling means can be integrated into the multiaxial joint so as to permit a simple modular connection of the multiaxial joint to the traction means. 
         [0029]    Furthermore, preferably standardized coupling means may be arranged on the outside of the multiaxial joint, to which means a corresponding traction means can be connected. The coupling means may be connected to short traction means inside the multiaxial joint, the means transmitting the drive forces of the traction means mounted on the outside into the interior of the multiaxial joint. 
         [0030]    The arrangement of a plurality of multiaxial joints one behind the other increases the number of the degrees of freedom of the resulting assembly of joints in a corresponding way. To this end the distal joint section of the first multiaxial joint can be firmly connected to the distal joint section of the further next multiaxial joint, with the traction means for the further multiaxial joint being advantageously passed through the first multiaxial joint. This prevents a situation where upon movement of the multiaxial joint objects get stuck on the traction means positioned on the outside. To permit such a guidance of the traction means through the multiaxial joint, the proximal joint section may be connected to the distal joint section by way of at least one continuous channel that is open at both ends. The traction means can pass through the multiaxial joint by way of said channel. Of course, a separate channel which is flexible and sleeve-shaped preferably at least in portions and which guides each individual traction means can also be provided for each traction means. 
         [0031]    This design can be further improved when traction means acting against each other, or the advance movement and the return movement of a revolving or circulating traction means for the further downstream multiaxial joint, are twisted by at least about 180° in the first multiaxial joint. Owing to the twisting the different movements of the two traction means can be offset against one another during movement of the first multiaxial joint so that a movement in the first multiaxial joint has no impact on the traction means in the interior. The twisting can be preset by a corresponding twisted run of the channels in the multiaxial joint. 
         [0032]    The multiaxial joint in one of the above-described designs can particularly be a basic element of a robotics kit that comprises a plurality of structural elements that are dovetailed or matched to one another and can be interconnected in an easy way via standardized mechanical interfaces so as to provide artificial limbs. The structural elements of the kit can particularly comprise connection elements, traction means and/or actuator elements. 
         [0033]    The invention is described by way of example hereinafter with reference to several embodiments. The features that are different in the individual designs can hereby be combined in any desired way according to the above description if the advantages specifically resulting from a particular combination should be of relevance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a side view on an embodiment of the multiaxial joint according to the invention in different swivel positions; 
           [0035]      FIG. 2  is a schematic perspective illustration of an exemplary assembly of joints with two successively arranged embodiments of the multiaxial joint according to the invention; 
           [0036]      FIG. 3  is a schematic perspective view of a further embodiment of the multiaxial joint according to the invention with a view onto the interior of the joint with omission of individual structural elements; 
           [0037]      FIG. 4  is a further schematic perspective view of the embodiment of  FIG. 3  with a view onto the interior of the joint with omission of individual structural elements; 
           [0038]      FIG. 5  is a schematic sectional view along plane V-V of  FIG. 1 ; 
           [0039]      FIG. 6  is a schematic front view taken in viewing direction VI of  FIG. 1 ; 
           [0040]      FIG. 7  is a schematic exploded illustration along plane VII-VII of  FIG. 6  of further structural elements of an embodiment of the multiaxial joint according to the invention; 
           [0041]      FIG. 8  is a schematic sectional view along plane VIII-VIII of  FIG. 6 ; 
           [0042]      FIG. 9  is a schematic sectional view through the mid-plane of a further embodiment of the multiaxial joint of the invention in the extended state; 
           [0043]      FIG. 10  shows a variant of the embodiment of  FIG. 10  in a schematic sectional illustration along the mid-plane; 
           [0044]      FIGS. 11-13  show further embodiments of the multiaxial joint according to the invention in schematic perspective views; 
           [0045]      FIG. 14  is a schematic illustration of an application of the multiaxial joint according to the invention. 
       
    
    
       [0046]    For explaining the figures, reference will be made in the following description to identical reference signs to designate structural elements of the same function. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    First of all, the basic structure and the function of a multiaxial joint  1  according to the invention shall be explained with reference to  FIG. 1 . 
         [0048]    The multiaxial joint  1  comprises a proximal joint section  2  and a distal joint section  4 . The proximal joint section  2  and the distal joint section  4  are movable relative to each other in two degrees of freedom. The one degree of freedom is a rotational movement D of the distal joint section  4  about its own axis, which simultaneously represents the rotational axis P of the rotational movement. The other degree of movement is a swivel movement S of the proximal joint section  2  about a swivel axis R, which extends preferably in a direction perpendicular to the rotational axis P or perpendicular to the connection line V of the distal joint section  4  and of the proximal joint section  2 . 
         [0049]      FIG. 1  schematically shows different swivel positions S 1 , S 2 , . . . S 7  of the distal joint section  4  with the connection element  6 . Of course, any desired intermediate position between the illustrated swivel positions S 1  . . . S 7  can be occupied by the distal joint section  4 . 
         [0050]    The proximal joint section  2  and the distal joint section  4  can also be designed in the form of sleeves or bushes, particularly with form-fit (positively locking) accommodating means for axles or shafts, or in pin form as a solid shaft. In the design of  FIG. 1  the proximal and the distal joint sections  2 ,  4  are protruding hollow shafts with a spline. In the proximal joint section  2  a connection element  6  is shown inserted in the form of a shaft that is splined at both sides. 
         [0051]    The proximal joint section  2  is provided in  FIG. 1  with a base element  8  into which a rotary bearing (not shown) can be integrated, so that the whole multiaxial joint  1  is rotatable about axis A. 
         [0052]    As shown in  FIG. 1 , the rotational axis P and the swivel axis R may intersect at a point O, so that the distal joint section, which is here shaped by way of example as a hollow pin, points always radially away from the swivel axis R, independently of the swivel position S 1  . . . S 7 . 
         [0053]    The multiaxial joint  1  according to the invention is distinguished by a compact structural shape in the case of which, as will be explained hereinafter with reference to  FIGS. 2 and 3 , a rotatory pivot joint and a rotatory swivel joint are integrated to form a structural unit in that they are slid or positioned into each other or within each other at least in part. The structural unit formed by pivot joint and swivel joint is arranged between the proximal and distal joint sections  2 ,  4  and can be recognized in  FIG. 1  as a closed joint section  9 . 
         [0054]    In the area of the joint section  9  the multiaxial joint  1  has a substantially capsule-shaped housing  10  in which at least the pivot joint needed for the rotational movement D is accommodated. The housing  10  can be designed approximately in the form of a ball and can be swivably connected via at least one bearing element  11  to the proximal joint section  2 . To this end at least one bearing element  11  is interposed between the housing  10  and the proximal joint section  2 . A ring bearing  12 , which provides access to the housing  10  through its central opening  14 , can act as such a bearing element  11 , as shown in  FIG. 1 . A rolling or sliding bearing is positioned in the ring portion of the ring bearing  12 . The ring bearing  12  can have a diameter corresponding approximately to the outer diameter of the housing  10 , so that great forces can be absorbed. The ring bearing  12  is preferably arranged on the outside of the housing. In the embodiment shown in  FIG. 1 , the ring bearing  12  forms a swivel joint  13  together with the swivable housing  10 . 
         [0055]    The connection element  6  and the base  8  are not necessarily part of the multiaxial joint, but are primarily part of a modular system the basic component of which forms the multiaxial joint  1 . To be able to connect the structural elements of the modular system in any desired way to the proximal joint section  2  and/or the distal joint section  4 , both joint sections  2 ,  4  comprise identical connection elements. Particularly, the modular system makes it possible to arrange several multiaxial joints  1 ,  1 ′ one after the other to form an assembly  15  of joints, as is shown in  FIG. 2 . Here, the distal joint section  4  of the multiaxial joint  1  is connected to the proximal joint section  2 ′ of the further multiaxial joint  1 ′. On the whole, this combination yields a compact multiaxial joint having four degrees of freedom. If one includes the rotation of the proximal joint section  4  about the base  8 , one will even obtain five degrees of freedom. For instance, the further multiaxial joint  1 ′ is moved with the distal joint section  4  along the swivel movement S and the rotational movement D. The further multiaxial joint  1 ′ adds a further swivel movement S′ of the distal joint section  4 ′ and a further rotational movement D′ of the distal joint section  4 ′ about its own axis. 
         [0056]    A preferred, but not exclusive, application of the multiaxial joint according to the invention is the field of robotics where it is intended to predominantly map the functionality of an elbow joint. The compact structural shape is preferably accomplished in that traction means are used for driving the multiaxial joint, so that the actuators can be arranged remote from the multiaxial joint. 
         [0057]    On the basis of  FIGS. 3 and 4 , the structure of a multiaxial joint  1  that is driven according to the invention via fraction means is explained by way of example. In  FIGS. 3 and 4 , parts of the multiaxial joint  1 , such as the housing  10 , are not plotted to permit a look at the interior of the multiaxial joint  1 . 
         [0058]    With reference to  FIG. 3 , the drive of the rotational movement D of the distal joint section  4  in one direction is first of all described. The distal joint section  4  is connected to a cam- or disc-shaped drive member  16  for rotation therewith; in the case of a design of the distal joint section  4  in the form of a solid shaft or a hollow shaft, the drive member can also be formed directly by a support portion of the shaft. 
         [0059]    The drive member  16  comprises a holding element  18  which has a traction means  20 , e.g. a wire cable, fastened to it. As shown in  FIG. 3 , the traction means  20  may be part of a Bowden cable  22  positioned outside the multiaxial joint  1 . As an alternative, the Bowden cable may also be mounted in the interior of the multiaxial joint. 
         [0060]    The drive member  16  further comprises a support portion  24  along which the traction means  20  is wound and guided during the rotational movement D. In this design it is part of a pivot joint  26  which is accommodated in the multiaxial joint  1  to swivel about the swivel axis R. 
         [0061]    The rotational movement D is produced by a tractive force Z D  which acts on the traction means  20  and is transmitted  4  in the form of a torque via the traction means  20  fastened along the support  24  on the circumference of the drive member  16  and on the holding element  18  on the distal joint section. Due to the traction Z D  on the traction means  20  the means is unwound under rotation of the drive member  16 . If the support portion  24  is dimensioned such that several windings of the traction means  20  are wound onto the drive member  16 , rotational movements of more than 360°, i.e. several revolutions, can also be generated with this kind of structure. The tractive force Z D  is generated by actuators (not shown) acting on the traction means  20  at a place remote from the multiaxial joint  1 . 
         [0062]    As shown in  FIG. 3 , the multiaxial joint  1  comprises a forked section  28  having fork legs  30 ,  32  that may be composed of two identical joined halves. The two fork legs  30 ,  32  are each formed by a ring bearing  12  for the swivel movement S (cf.  FIG. 1 ). Hence, the pivot joint  26  is enclosed at the sides by the swivel joint  13 . Owing to the use of the ring bearing  12 , part of the rotary bearing  26 , particularly the drive member  16 , can extend through the plane formed by the ring bearings  12 . 
         [0063]      FIG. 3  shows the generation of the rotational movement D just in one direction. For the generation of the rotational movement in the opposite direction, a further traction means is needed that counteracts the traction means shown in  FIG. 3  in that it unwinds in opposite direction.  FIG. 4  schematically shows this additional traction means having reference sign  34 . 
         [0064]    The traction means  20 ,  34  may be connected to linearly operating actuators, such as e.g. artificial muscles, which act as agonist and antagonist of the respective rotatory movement S, D. 
         [0065]    As an alternative to the design shown in  FIG. 3 , in which the end of the traction means  20  is fastened to the drive member  16 , the traction means  20  may just be wound around the drive member  16  and may be guided with its other end out of the multiaxial joint  1  again. In this design the traction means  20  is designed as a circulating or revolving continuous endless loop which drives the drive member  16  such as a drive roll. On the side of the actuator, a roll may also be used as the drive (not shown). 
         [0066]    With reference to  FIG. 4 , the drive of the swivel movement S is now explained, the drive being also implemented via two traction means  36 ,  38  counteracting each other; these, however, are preferably connected to form a loop  40  guided over the housing  10 . 
         [0067]    In this design, a part of the housing  10  is configured as a drive member  16  and a support portion  24 , respectively, to which the traction means  36 ,  38  is guided preferably tangentially. A tractive force Z S  which is acting on the traction means  36  is transmitted by way of a frictional and/or form-fit closure of the fraction means  36 ,  38  to the drive member  16  and the housing  10 . 
         [0068]    The housing  10  is held to swivel in the ring bearings  12  so that the tractive force Z S  swivels the housing and, with the housing  10 , the rotary bearing  26  which is held therein. 
         [0069]    The traction means  20 ,  34  for the rotary bearing  26  are passed through openings  42 , of which  FIG. 4  only shows the opening for the traction means  20 , into the interior of the housing  10  to the drive member  16 . Since the housing  10  is swiveled with the rotary bearing  26 , the relative position between the opening  42  and the drive member  16  is independent of the swivel movement S. The swivel movement S must be compensated by a loop  44  in the traction means. 
         [0070]      FIG. 5  shows how the traction means  20 ,  34  can be guided at opposite sides of the housing  10  through the openings  42  into the interior of the multiaxial joint  1  tangentially onto the support portion  24  of the drive member  16  of the pivot joint and can be tightly held in the holding element  18 . Furthermore, this figure shows the at least one ring bearing  12  schematically in section. In this embodiment the ring bearing comprises a ball bearing as the bearing element  11 , the running surfaces of said bearing being formed distally by the housing  10  and proximally by a fork leg  30 ,  32 . 
         [0071]    Due to the use of the forked section  28  the drive member  16  can be given a large circumference, so that increased drive forces can be utilized for the rotational movement. To be able to accommodate a correspondingly large drive member  16 , which can extend through the ring bearing  12 , the housing  10  can bulge outwardly in the form of a calotte out of the central opening  14  of the ring bearings  12 , as shown in  FIG. 5 . In these side members, accommodating means are also arranged for the traction means  20 ,  34  with the respective opening  42  (not shown). 
         [0072]      FIG. 6  shows, by way of example, the structure of the housing  10  which is made up of two pairs of identically designed housing shells  46 ,  48 , which are held together in the direction of the swivel axis R by way of a screw-, rivet- or lock-type connection and are arranged at both sides of a corresponding ring bearing. The embodiment shown in  FIG. 7 , in which openings  49  extend through all housing shells  46 ,  48 , is particularly suited for great forces, so that the housing can be held together by continuous screws (not shown) and fastened to the forked section  28  (cf.  FIG. 6 ). The housing  10  comprises at least one recess  50  which itself can represent a bearing surface or, however, accommodate a raceway of a rolling or sliding bearing. 
         [0073]    The interior of the shell parts  46 ,  48  serves to accommodate the rotary bearing  26 , the further structure of which shall now be explained with reference to  FIG. 8 . 
         [0074]    The distal joint section  4  is thus continued in the housing  10  in the form of a shaft  51  which is supported by means of rolling and/or sliding bearings at least at one place, but preferably at two places  52 ,  54  for supporting increased forces and moments. The drive member  16  is preferably arranged between the two bearing places  52 ,  54 . In the housing  10 , corresponding accommodating means are formed for supporting the distal joint section  4 . 
         [0075]    As shown in  FIG. 2 , a plurality of multiaxial joints  1 ,  1 ′ can be connected in series. The traction means  20 ′,  34 ′,  36 ′,  48 ′ of the further downstream multiaxial joint  1 ′ can be guided on the outside past the preceding multiaxial joint  1 . To prevent any entanglement of the fraction means guided past the preceding multiaxial joint  1 , it is however better to guide the fraction means for the further multiaxial joint  1 ′ through the interior of the multiaxial joint  1 . Corresponding designs are shown in  FIGS. 9 and 10 , which shall be described hereinafter. 
         [0076]    According to the embodiment of  FIG. 9 , at least one channel  56 , which is open at both ends, extends continuously from the proximal joint section  2  to the distal joint section  4 . The traction means  20 ′,  34 ′,  36 ′,  38 ′ are passed through the channel  56  by the proximally arranged actuators through the first multiaxial joint  1  to one or several further multiaxial joints  1 ′. 
         [0077]    The housing  10  at its side facing the proximal end  2  is provided with a funnel-shaped inlet opening  57  which extends in the direction of the swivel movement S and tapers towards the distal joint section  4  and which is part of the channel  56  and prevents the traction means  20 ′,  34 ′,  36 ′,  38 ′ from colliding with the housing  10  in the course of the swivel movement S. 
         [0078]    To guide the individual traction means  20 ′,  34 ′,  36 ′,  38 ′ independently of one another, an individual channel  58 ,  59 ,  60 ,  62  may be provided for each of said traction means, the channels being continued in the region of the joint in flexible tubular sleeves  64 . The sleeves  64  extend between a proximal holding plate  66  and a distal holding plate  68 , so that short Bowden cables are formed in this area. Plastic sleeves of spherical or cylindrical segments may e.g. be used for the sleeves. Subsequently, the traction means are continued in the interior of the distal joint section. The length of the tubular sleeves is dimensioned such that even at the end points of the swivel movement there is provided a radius of curvature that is conforming to the standards and is adequately large for a low-friction operation of the traction means  20 ′,  34 ′,  36 ′,  38 ′. 
         [0079]    The proximal holding plate  66  is preferably stationarily held relative to the proximal joint section  2 , while the distal holding plate  68  is rigidly formed on or connected to the housing  10 . 
         [0080]    The distal joint section  4  is continued in the interior of the housing  10  as a hollow shaft. In this context, it is advisable to make the drive member  16  annular and to support it on its inside  70  to directly absorb the transverse forces that are needed for driving the same and are generated by the tractive means  20 ,  34 . On account of the large bearing diameter, it makes sense to use, at place  70 , a bearing capable of absorbing axial forces so as to utilize the surface pressures that are small on account of the bearing size. The axial forces are generated in this design by the tractive forces transmitted by the fraction means. 
         [0081]    A further bearing  72  can provide a support for tilt moments acting on the distal joint section  4 . 
         [0082]    The design shown in  FIG. 10  differs from the design according to  FIG. 9  only in that the bundle of the tubular sleeves  64  is twisted in the area between the holding plates  66 ,  68  by 180° to compensate the different bending radii arising during the swivel movement of the joint, and the resulting longitudinal displacements of the distal ends of the sleeves  64  positioned on the inside. The twisting is provided with reference sign  76  in  FIG. 10 . 
         [0083]    When the multiaxial joint  1  is used as a passive moved joint without drive members  16  or without drive members  16  connected to fraction means, the embodiments of  FIGS. 9 and 10  can serve the gentle passage of lines, e.g. electrical or fluidic lines, between the proximal and the distal end. 
         [0084]    Based on the preceding embodiments,  FIGS. 11 to 13  show further design variants. 
         [0085]    In the embodiment of  FIG. 11 , the distal joint section  4  is extended through the multiaxial joint  1  to the opposite side, resulting in a T-shaped basic structure. As an alternative, the extended section can be firmly connected to the housing  10 , so that it cannot perform any rotational movements. 
         [0086]    In the embodiment of  FIG. 12 , the proximal joint section  2  is extended through the multiaxial joint  1  to the opposite side.  FIG. 13  shows a combination of  FIGS. 11 and 12  with distal and proximal joint sections extended at both sides, and with one or two joint sections  76  that extend along the swivel axis R and, with swivel movement S, perform a rotational movement. 
         [0087]    With the embodiments of  FIGS. 11 to 13  the modular system can be enlarged to deal with further kinematic drive problems. This shall be briefly sketched hereinafter with reference to  FIG. 14 . 
         [0088]      FIG. 14  shows a joint assembly with two inventive multiaxial joints  1 ,  1 ′ arranged one after the other for simulating the flexibility of a human arm. The first multiaxial joint  1  serves as a shoulder joint; the downstream additional multiaxial joint  1 ′ serves as an elbow joint. The arrangement of the multiaxial joints  1 ,  1 ′ corresponds to the arrangement shown in  FIG. 2 , with the only difference that the connection element  6  has a greater length than in  FIG. 2 . 
         [0089]    The proximal end  2  of the first multiaxial joint  1  can be connected to a torso structure (not shown in  FIG. 14 ). The distal end  4 ′ of the downstream multiaxial joint  1 ′ is connected to a gripper  80  via a joint  82 . 
         [0090]    The multiaxial joint  1 ′ is flexed and extended by actuators  84 ,  86  connected to the traction means  36 ,  38 . In  FIG. 14 , pneumatic muscles are shown by way of example as actuators. 
         [0091]    In the flexed position of the elbow joint shown in  FIG. 14 , the actuator  84  serving as the flexor is contracted; its antagonist, the actuator  86  serving as the extensor, is stretched. 
         [0092]    The actuators  88 ,  90  effect a corresponding rotation of the connection element  6 ′, which connects the gripper  80  to the multiaxial joint  1 ′. The actuators  88 ,  90  are connected to the fraction means  20 ,  34  in a corresponding way. 
         [0093]    The function of the multiaxial joint  1 ′, just like the function of the multiaxial joint  1 , is the same as has been described above. 
         [0094]    Owing to the design as a modular system, the joints  1 ,  1 ′ as well as the connection elements  6 ,  6 ′ can be put together easily in any desired combination. 
         [0095]    Of the above-described embodiments, further modifications are possible without departing from the teaching according to the invention. 
         [0096]    Instead of the described wires or Bowden cables, other traction means, such as chains or belts, particularly toothed belts, can also be used. 
         [0097]    The connection element  6 ,  6 ′ itself may also be hollow to permit the passage of traction means therethrough. Shortly before the ends of the connection element, openings may be provided for guiding the fraction means to the outside. As an alternative, the connection element can also be preassembled with traction means positioned on the inside and can comprise coupling means to which traction means are fastened from the outside. 
         [0098]    Instead of the ball-shaped housing  10 , other, preferably rotationally symmetric, housing shapes, for instance cylindrical housing shapes, may be used. A housing enclosing the pivot joint  26  can also be omitted, and instead of the housing, a shaft held by at least one bearing element  11  can be used. In this case, similar to the distal joint section  2 , the drive member  16  is mounted on the shaft. 
         [0099]    Each of the above-described embodiments shows an active multiaxial joint  1  by which a force or a movement is to be transmitted to the distal joint section for handling loads. The multiaxial joint  1 , however, can be used in a similar way also as a passive joint if the bearing elements  11  of the swivel joint  13  and the bearings of the pivot joint  26  are designed e.g. as friction bearings in an automatically locking way or are provided as locking devices with which the bearings can be fixed. This can e.g. be accomplished in that the locking elements are used instead of actuators and fix the fraction means. 
         [0100]    Finally, in a kinematic reversal of the above-described structure the swivel joint  13  can also be arranged within the pivot joint  26 .