Abstract:
A displacement device for producing a rotational movement with an output element  3   a  adjustable in angle by operating a drive element  2   a  has a load torque lock  1   a  mounted between the drive element  2   a  and the output element  3   a  and which blocks with force locking connection torque introduced on the output side and transfers torque introduced on the drive side to the output element  3   a . Between the drive element  2   a  and the load torque lock  1   a  and/or between the output element  3   a  and the load torque lock  1   a  is a play compensating device  5   a  which compensates the torsion angle play between the drive element  2   a , the output element  3   a  and the load torque lock  1   a . The displacement device is used in particular for window lifters or seat adjusters of vehicles.

Description:
CROSS REFERENCE  
         [0001]    This application claims priority of German Application No. 199 26 994.7 filed 8 Jun. 1999, a copy of which is Attachment A hereto, the disclosure of which is incorporated fully herein by reference.  
         DESCRIPTION  
         [0002]    The invention relates to a displacement device according to the preamble of claim  1 .  
           [0003]    From DE 41 20 617 C2 a displacement device is known which has a load torque lock with which torque on the drive side is transferred in both directions to an output element whilst torque on the output side is blocked in both directions by the load torque lock and the force is introduced into a displacement housing and is consequently not transferred to the drive element.  
           [0004]    Between the drive element and the load torque lock the torque on the drive side is transferred by means of elements which engage in each other with keyed engagement. Since the position of the locking elements of the load torque lock changes through tolerances and wear as a result of high flat surface pressures, in order to reach the required functional reliability of the known displacement device it is necessary to incorporate a large play so that during functioning a torsion angle play is present between the interengaging elements without which a stepped transfer or change of direction of the torques on the drive side is not possible. A minimum torsion angle play must also therefore be present between the interengaging elements of the drive element and the load torque lock in order to guard against wear and enable a certain elastic deformation.  
           [0005]    Opposite this however too much torsion angle play, particularly in the case of a stepped transfer of the torque on the drive side, has a noticeable detrimental effect since the torsion angle play causes a correspondingly large idling path or idling stroke of the drive element. Furthermore too much torsion angle play can lead when reversing the movement to a detrimental reversal play and to inaccurate handling.  
           [0006]    The known displacement device has a relativeLy large reversal play in the brake unit conditioned by the tolerances of the structural parts. In order to restrict this, manufacture must be carried out precisely within a narrow tolerance band. The assembly of the individual component parts which are provided with small tolerances is therefore expensive since the component parts which are to be connected together have to be positioned very precisely relative to each other.  
           [0007]    The object of the present invention is therefore to provide a displacement device with optimum torsion angle play between a drive element, an output element and a load torque block which on the one hand is restricted to a minimum and on the other ensures a reliable force and torque transfer and which during assembly requires no adjustment and even after long term use requires no adjustment of the torsion angle play.  
           [0008]    This is achieved according to the invention through a displacement device having the features of patent claim  1 .  
           [0009]    According to the invention a play compensating device which balances the torsion angle play between the drive element, output element and the load torque block, is mounted between the drive element and the load torque block or between the output element and the load torque block so that the functionally-conditioned torsion angle play between the drive element and the load torque lock or between the load torque lock and the output element is set and adjusted automatically. An automatic setting of the optimum torsion angle play thereby takes place taking into account the tolerances of the component parts and the adjustment is carried out taking into account the wear on the component parts so that a minimum idling stroke is ensured during operation and a high functional reliability of the displacement device is ensured taking into account the unavoidable wear. The manufacture of″the individual component parts is thus considerably more economical, assembly of the displacement device is simplified and rejects are restricted to a minimum.  
           [0010]    The load torque lock preferably has at least two locking elements mounted in a cylindrical displacement housing, with the clamping faces of the locking elements acting with predetermined pretension on the displacement housing under the action of the play compensating device which is mounted at least in part between opposing expanding faces of the locking elements and presses these locking elements apart from each other. Torque introduced on the output side thereby increases the bearing force of the clamping faces and thus of the locking elements against the displacement housing.  
           [0011]    The play compensating device can be guided in the drive element and can be connected to a spring which pretensions the play compensating device in the play compensating direction whilst the locking elements are loaded with pretensioning force against the play compensating direction.  
           [0012]    The play compensating device can be formed in different ways in order to ensure the locking elements bear on the displacement housing with the predetermined pretensioning force and in order to guarantee an automatic adjustment which becomes necessary as the component parts wear down. In a first embodiment the play compensating device consists of at least one wedge mounted between the expanding faces of the locking elements, where the wedge faces oppose the expanding faces of the locking elements and where the wedge is guided displaceable with a wedge guide in keyed connection in a slide guide of the drive element and is pretensioned radially by means of a spring so that the wedge faces adjoin the expanding faces free of play.  
           [0013]    In order to ensure that the wedge on the one hand in the absence of any drive torque engenders the optimum setting and adjustment and does not hinder the movement of the locking elements, but on the other hand in the event of torque on the drive side is not radially displaced by the locking elements, and in order to keep the system able to function in the widest possible range, the material matching of the expanding faces and of the wedge faces on the one hand and of the active faces of the wedge guide and the slide guide of the drive element on the other hand is predetermined so that with the absence of drive torque the expanding faces can move the wedge against the action of the spring, but in the event of load on the drive side the wedge is held in its position. This is caused for example by a small friction value between the wedge faces and the expanding faces as well as by a high friction value between the guide face of the wedge and the slide guide of the drive element.  
           [0014]    As an alternative or in addition the displacement device or the play compensating device can be geometrically designed so that the wedge angle α which the wedge faces include between themselves, the minimum friction angle σ sperr,min  in the event of load on the drive side and the maximum friction angle σ sperr,max  in the event of load on the output side between the wedge faces and the expanding faces as well as the minimum friction angle σ antr, min  in between the wedge guide and the slide guide meets the conditions  
           2*σ sperr, max &lt;α 
           σ antr, min +σ sperr,min &gt;α/2  
           [0015]    in which σ=arc tan μ and μ is the friction value between the friction faces formed from the surface pairings wedge surface/expanding surface and wedge guide/slide guide.  
           [0016]    In order to intensify the clamping action of the wedge the wedge guide can be arranged radially off-set from the expanding faces of the locking elements. A reduction of the (radial) height of the wedge also leads to an intensification of the clamping action so that when necessary the wedge angle can also be selected as obtuse.  
           [0017]    In order to produce a defined spot or linear contact between the wedge and the expanding faces of the locking elements, the expanding faces of the locking elements or the wedge faces are formed ball-shaped so that the slide action is minimal as a result of the slight friction of the surfaces which slide on each other and thus easy adjustment is guaranteed.  
           [0018]    In a second embodiment the play compensating device consists of at least one cylindrical roller or ball mounted between the expanding faces of the locking elements, wherein the roller or ball guide is mounted in a slide guide of the drive element and its outer face adjoins with linear or spot contact against the flat or ball-shaped expanding faces of the locking elements free of play.  
           [0019]    In a third embodiment the play compensating device consists of at least one eccentric mounted rotatable between the expanding faces of the locking elements and preferably formed as a stepped bolt, with an eccentric stud mounted in a bore of the drive element and is radially pretensioned by a torsion spring so that the eccentric faces adjoin the expanding faces of the locking elements free of play.  
           [0020]    Through the shaping and/or surface conditions the eccentric faces adjoin the expanding faces of the locking elements and the eccentric stud is connected to the drive element so that when the drive element is actuated the eccentric is blocked and does not obstruct the movement of the locking elements.  
           [0021]    An automatic compensation of the optimum torsion angle play can be provided with different structural forms of the displacement device or drive element, output element and the load torque lock according to the features of sub-claims  14  to  29 . These embodiments comprise inter alia the arrangement of pairs of locking elements in two superposed planes, applying a pretensioning force to the play compensating device by means of compression, yoke or formed springs, with or without additional force transfer elements, such as shears and the like and the positive-locking torque transfer from the drive element to the output element when the locking action is lifted through the load torque lock. 
       
    
    
       [0022]    Further advantages are produced from the following described embodiments in which:  
         [0023]    FIGS.  1  to  7  show diagrammatic illustrations for explaining the functioning principle of different play compensating devices for displacement devices with a load torque lock;  
         [0024]    [0024]FIG. 8 shows a cross-sectional view through a load torque lock with wedges guided in the drive element for adjusting brake elements;  
         [0025]    [0025]FIG. 9 shows a cross-sectional view through a load torque lock with wedges guided in the drive element and with scissor arms for adjusting locking elements;  
         [0026]    [0026]FIG. 10 shows a plan view and  
         [0027]    [0027]FIG. 11 shows a longitudinal sectional view through a load torque lock with wedges guided in the drive element and wire springs connecting these together as pretensioning elements;  
         [0028]    [0028]FIG. 12 shows a load torque lock according to FIGS. 10 and 11 with a yoke or formed spring between the wedges adjusting the locking elements;  
         [0029]    [0029]FIGS. 13 and 14 show a load torque lock with wedges connected by springs and adjoining is the end faces of the locking elements in the case of different play;  
         [0030]    [0030]FIGS. 15 and 16 show a load torque lock with wedges connected by springs and enclosed by the locking elements with different play;  
         [0031]    [0031]FIG. 17 shows a load torque lock with rod-like drive element guided through the output element and the wedge of a play compensating device, and  
         [0032]    [0032]FIG. 18 shows a load torque lock as in FIG. 17 with a rod-like drive element which is pushed through a bore of the output element and onto the end of which is pushed a wedge of a play compensating device. 
     
    
       [0033]    The diagrammatic illustrations of the load torque locks in FIGS.  1  to  7  serve only to explain the functioning principle of play compensation for displacement devices. FIGS.  8  to  18  show various different embodiments for concrete designs of displacement devices and play compensating devices used therein. The reference numerals used in the function illustrations of FIGS.  1  to  7  as well as the reference numerals used to designate the individual parts of the displacement devices in the concrete embodiments of FIGS.  8  to  18  coincide where they relate to the same or similar functioning component parts. The alphabetical additions to the reference numerals similarly designate the same or similar type of functioning elements of the various embodiments.  
         [0034]    [0034]FIG. 1 shows a sectional view through a double-sided acting displacement device  1   a  with a displacement housing  10  in which the functional parts of a load torque lock are mounted with automatic play compensation. A drive element formed as a drive lever  2   a  is mounted rotatable about an output axle  30  which is connected to an output element  3   a . Between the drive element  2   a  and the output element  3   a  there are locking elements  4   a  and  4   a ′ formed as segments and adjoining the cylindrical inner face of the displacement housing  10  with a part of their peripheral faces  42   a ,  42   a ′ which are formed as locking faces  43   a  and  43   a′.    
         [0035]    The opposing expanding faces  41   a ,  41   a ′ of the locking elements  4   a  and  4   a ′ are adjoined by wedge faces  51   a  and  51   a ′ of a wedge  5   a  which causes an automatic play compensation. The wedge  5   a  is mounted with a wedge guide  52   a  in a recess  20   a  of the drive lever  2   a  formed as a slide guide and is pretensioned by means of a spring  7   a  so that the wedge faces  51   a ,  51   a ′ press in the play compensating direction circular against the expanding faces  41   a ,  41   a ′ of the locking elements  4   a ,  4   a ′ and thus bring the locking faces  43   a ,  43   a ′ of the locking elements  4   a ,  4   a ′ to bear against the cylindrical inner face of the displacement housing  10 .  
         [0036]    The locking elements  4   a ,  4   a ′ are pretensioned by a locking element spring  6   a  circular against the play compensating direction so that the expanding faces  41   a ,  41   a ′ endeavour to press the wedge  5   a  out from the interspace between the expanding faces  41   a  and  41   a ′. As explained in further detail below from the enlarged detailed illustration of the play compensating device according to FIGS. 2 a  to  2   c  the friction conditions between the expanding faces  41   a ,  41   a ′ and the wedge faces  51   a ,  51   a ′ on the one hand and the wedge guide  52   a  and the slide guide  20   a  on the other hand are produced so that when torque is applied on the drive side the locking elements  4   a ,  4   a ′ are entrained free of play by the wedge  5   a , but on the other side the locking elements  4   a  and  4   a ′ are dragged without hindrance by the wedge  5   a  for play compensation, i.e. in the rest state are pressed through the wedge  5   a  under the action of the spring  7   a  with their locking faces  23   a ,  23   a ′ against the displacement housing  10 .  
         [0037]    This function conditions a small friction value at the friction face formed between the wedge faces  51   a ,  51   a ′ and the expanding faces  41   a ,  41   a ′ and a large friction value at the friction face formed between the wedge guide  52   a  and the slide guide  20   a  so that under certain geometric conditions the wedge  5   a  is prevented from being pressed out from the interspace between the expanding faces  41   a ,  41   a′.    
         [0038]    When torque is introduced on the drive-side through the drive lever  2   a  the torque is transferred through the wedge  5   a  to the expanding faces  41   a  or  41   a ′ of the locking elements  4   a  or  4   a ′ depending on the direction of rotation and the locking elements  4   a  or  4   a ′ are entrained in the circumferential direction since the bearing contact of the locking faces  43   a ,  43   a ′ of the locking elements  4   a ,  4   a ′ against the cylindrical inner face of the displacement housing  10  is not sufficient to block the torque which is introduced. After the locking element  4   a ,  4   a ′ has been moved slightly in the circumferential direction through the torque introduced on the drive side, the slide guides  21   a  and  21   a ′ of the drive lever  2   a  come into positive-locking engagement with claws  31 ,  32  on the output side and entrain the output element  3   a  in keyed engagement into the relevant rotary direction of the drive lever  0 . 2   a . Anadditional keyed connection between the drive element  2   a  and output element  3   a  of this kind which is activated after a slight rotation has been introduced and transfers the further transfer of the torque exerted by the drive element  2   a  to the output element  3   a , is however not absolutely necessary since the transfer of the torque from the drive element  2   a  to the output element  3   a  can also take place through the wedge  5   a  of the play compensating device and through the locking elements  4   a ,  4   a ′ to the output element  3   a.    
         [0039]    With the introduction of torque on the output side depending on the direction of rotation the outer face of the output element  3   a  is loaded more heavily at points A or A′ and presses the inner locking element faces  44   a ,  44   a ′ radially apart so that the locking faces  43   a  or  43   a ′ intensify their bearing contact against the cylindrical inner face of the displacement housing  10  and thus block the torque introduced on the output side.  
         [0040]    [0040]FIG. 2 a  shows in an enlarged detailed illustration of FIG. 1 a play compensating device with a wedge  5   a  as the play compensating element and a section of the drive lever  2   a  with slide guide  20   a  provided therein as a recess in which the wedge guide  52   a  of the wedge  5   a  is mounted and adjoins with keyed engagement against the side walls of the slide guide  20   a  of the drive lever  2   a  running perpendicular to the drive direction, but is displaceable perpendicular to the drive direction inside the slide guide  20   a.    
         [0041]    The wedge faces  51   a  and  51   a ′ of the wedge  5   a  are adjoined by the expanding faces  41   a  and  41   a ′ of the locking elements  4   a ,  4   a ′. In order to actuate the locking elements  4   a ,  4   a ′ connected in force-locking engagement with the output element  3   a  the wedge  5   a  is guided in the drive element  2   a  with the wedge guide  52   a  and biased with a compression spring  7   a  so that the wedge faces  51   a  and  51   a ′ adjoin free of play the expanding faces  41   a ,  41   a ′ of the locking elements  4   a ,  4   a ′ without being pressed apart against a spring which may be present (for example the locking element spring  6   a  according to FIG. 1) or the locking elements  4   a ,  4   a ′ lifting off from the cylindrical inner wall of the displacement housing  10 .  
         [0042]    [0042]FIG. 2 b  shows the force and friction conditions in the event of load on the drive side, i.e. with the action of the drive element  2   a  on the wedge  5   a . In the event of entrainment of the wedge  5   a  through the drive element  2   a  against a side of the locking element  4   a  or  4   a′, α/ 2   acts as the wedge angle. In the event of a force equilibrium, i.e. in the blocking state  
         σ antr +α sperr =α/2  (1)  
         [0043]    In order to ensure a secure hold, the sum of the friction values when the wedge  5   a  slips through must however be larger than the wedge angle α/2 so that in the event of load on the drive side the following applies  
         σ antr, min +σ sperr, min &gt;α/2  (2)  
         [0044]    in which  
         [0045]    σ sperr,min  is the minimum friction angle and σ sperr,max  is the maximum friction angle between the wedge faces  51   a  and the expanding faces  41   a , σ antr,min  the minimum friction angle between the wedge guide  52   a  and the slide guide  20   a , σ=arc tan μ and μ is the friction value between the friction faces formed from the surface pairings wedge face/expanding face and the wedge guide/slide guide.  
         [0046]    [0046]FIG. 2 c  shows the forces and friction angle in the event of load on the output side, i.e. in the event of load on the side of the locking elements  4   a  or  4   a ′. In this case of load on the wedge  5   a  free of drive torque from the sides of the locking element  4   a  or  4   a ′, the sum of the limit friction values must be  
         2*σ sperr, max &lt;α  (3)  
         [0047]    so that the wedge  5   a  does not impede the movement of the locking elements  4   a ,  4   a ′. If this condition is fulfilled the wedge  5   a  slips through without any drive torque as a result of force exerted by the locking elements  4   a ,  4   a ′, whilst it is blocked in the event of force exerted by the drive element  2   a  on the locking elements  4   a ,  4   a′.    
         [0048]    So that the system functions in the largest possible range of σ sperr  it is advantageous to make σ antr,min  as large as possible, e.g. by providing corresponding roughness or mini-serrations.  
         [0049]    [0049]FIG. 3 shows a possibility of intensifying the self-locking effect of a wedge  5   b  to guard against the wedge  5   b  being pressed out through the action of the expanding faces  41   b ,  41   b ′ of the locking elements  4   b ,  4   b ′ on the wedge  5   b  by providing a contact bearing for the wedge  5   b  at two points through canting. This is achieved through an eccentric arrangement of the wedge guide  52   b  in relation to the expanding faces.  41   b ,  41   b ′of the locking elements  4   b ,  4   b ′ wherein the height of the wedge guide  52   b  and the distance s of the upper edge of the wedge guide  52   b  from the contact point of the expanding faces  41   b ,  41   b ′ is variable.  
         [0050]    With a decrease in the height H or through an increase in the distance s the canting effect is intensified so that the wedge angle α of the wedge  5   a  can become more obtuse. In the event that the distance s is equal to zero then the arrangement exists according to the method of operation of FIG. 2. With an increasing distance s through the off-set wedge guide an intensifying canting effect is produced which increases the contact bearing force and hinders the system from slipping through in the event of drive load with significantly smaller friction angles. With a predetermined wedge angle α the minimum height H of the wedge guide  52   b  and thus a minimum distance s of the centre of the wedge guide  52   b  from the centre of the expanding faces  41   b ,  41   b ′ of the locking elements  4   b ,  4   b ′ must be provided in order to guarantee the functioning of the play compensating device.  
         [0051]    [0051]FIG. 3 shows a ball-shaped design of the expanding faces  41   c ,  41   c ′ of the locking elements  4   c ,  4   c ′ wherein the wedge faces  51   c ,  51   c ′ fix the angle for the geometric conditions described above. As an alternative the wedge faces  51   c  and  51   c ′ can be made ball-shaped and the expanding faces  41   c ,  41   c ′ of the locking elements  4   c ,  4   c ′ can be flat.  
         [0052]    [0052]FIG. 5 shows a function diagram in which instead of a wedge as with the displacement device described above, a cylinder or a ball is provided as the play compensating element  5   d  and is guided analogous with the embqdiments described above with a guide  53   d  in a slide guide  20   d  of the drive element  2   d . The play compensating element  5   d  lies with its cylinder or ball surface  51   d  against the expanding faces  41   d ,  41   d ′ of the locking elements  4   d ,  4   d′.    
         [0053]    [0053]FIG. 6 shows a displacement device  1   e  which corresponds to the displacement device  1   a  according to FIG. 1. As opposed to the displacement device  1   a  according to FIG. 1 here however a play compensating device is provided in the form of an eccentric  5   e  which is designed as a stepped bolt pretensioned with a torsion spring and mounted with a guide pin  52   e  in a bore  20   e  of the drive element formed as a drive lever  2   e , the eccentric adjoining by its eccentric faces  51   e  the expanding faces  41   e  and  41   e ′ of the locking elements  4   e ,  4   e′.    
         [0054]    [0054]FIGS. 7 a  and  7   b  show on an enlarged scale details of the play compensating device according to FIG. 6 and the geometric conditions which are essential for the functioning of the play compensating device in the event of load on the output side (FIG. 7 a ) on the part of the locking elements and in the event of load on the drive side (FIG. 7 b ) on the part of the drive element  2   e . The spring tensioning of the eccentric  5   e  is entered in the direction of the arrow F EP .  
         [0055]    The contact and friction conditions of the play compensating device shown in FIGS. 6, 7 a  and  7   b  are designed so that the eccentric  5   e  is blocked when the drive element  2   e  is actuated but does not obstruct the movement of the locking elements  4   e  and  4   e ′ which is necessary for a satisfactory locking of torque introduced on the output side, even when taking into account wear on the component parts.  
         [0056]    According to FIG. 7 a  the contact bearing points between the eccentric  5   e  and the locking elements  4   e ,  4   e ′ are designed so that in the event of load through the locking elements  4   e  and  4   e ′ a relatively large angle α sp max  is produced between the force direction of the contact points and the horizontal which is greater than the maximum friction angle so that in the event of load on the output side the eccentric  5   e  can be turned back by the locking elements  4   e ,  4   e ′ against the pretensioning force F EF  of the eccentric  5   e.    
         [0057]    With the conditions illustrated in FIG. 7 b  in the event of load on the drive side a minimum friction angle α sp min  is produced on the other hand between the expanding faces  41   e  and  41   e ′ of the locking element  4   e ,  4   e ′ and the eccentric  5   e  which prevents the eccentric  5   e  from turning back and thus ensures a direct and play-free force transfer. The friction area between α sp min  and α sp max  is the friction area in which the friction values of the surface bearing between the eccentric and the locking elements have to lie for a functioning of the system. The force engagement point between the drive element and the bearing of the eccentric is produced from the force direction of α sp min . The friction value between these faces must thereby be such that the slip through friction angle σ=arc tan μ is greater than the angle α antr min  between this force direction and the normal to the circle, i.e. the bearing of the eccentric in the drive must be made consciously rough.  
         [0058]    In other words: If the locking elements  4   e ,  4   e ′ are compressed together then the eccentric  5   e  has to turn away, from which a maximum angle α sp max  results. All the friction angles must therefore be smaller than α sp max  so that the eccentric  5   e  can slip away.  
         [0059]    FIGS.  8  to  19  illustrate various different variations of the load torque locks for displacement devices in which the functionally conditioned torsion angle play between the drive element and load torque lock is automatically set and adjusted.  
         [0060]    For this purpose FIGS.  8  to  16  show embodiments for load torque locks with locking elements mounted in two planes for each of the two torsion directions of the displacement device, whilst in FIGS.  17  to  24  embodiments are shown for load torque locks with locking elements mounted in one plane for each of the two turning directions of the displacement device.  
         [0061]    The part of a displacement device shown in FIG. 8 having automatic compensation of the functionally conditioned torsion angle play has on the drive side a follower disc  2   f  which is mounted rotatable inside a displacement housing  10  and is connected to a drive lever (not shown) which can swivel in one or other rotary direction and engenders a corresponding rotary movement of the follower disc  2   f  in one or other rotary direction. The follower disc  2   f  has diametrically opposite window-shaped openings  21   f ,  21   f ′ in which claws  31   f ,  31   f ′ project of an output element  3   f  which is rotatable about a rotary axis  30  and to which torque is transferred which is exerted on the follower disc  0 . 2   f.    
         [0062]    The load torque lock  1   f  contains in two superposed planes two pairs of segment type locking elements  4   f ,  4   f ′ and  4   f ′,  4   f ′″, between whose opposing chord faces  45   f ,  45   f ′ and  45 ″,  45   f ′″ is mounted the output element  3   f . The output element  3   f  and the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ thereby contact one another when torque is introduced on the output side at points A, B′ and B, A′ dependent on the rotary direction of the output element  3   f.    
         [0063]    The claws  31   f ,  32   f  on one side and the expanding faces  41   f ,  41   f ′ and  41   f ″,  41   f ′″ of the locking elements  4   f ,  4   f ′and  4   f ″,  4   f ′″ are adjoined in each plane of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ by locking element springs  6   f ,  6   f ′ which consist of a W-spring and a compression spring mounted to reinforce the W-spring at the ends adjoining the expanding faces  41   f ,  41   f ′ and  41   f ″,  41   f ′″ of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″. The springs  6   f ,  6   f ′ cause the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ to adjoin both the output element  3   f  and also with their clamping faces  43   f ,  43   f ′ and  43   f ″,  43   f ′″ which are part of the peripheral faces  42   f ,  42   f ′ and  42   f ″,  42   f ′″ of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ with larger diameter, the displacement housing  10 .  
         [0064]    The angled ends of two scissor arms  81   f ,  82   f  are mounted in peripheral recesses of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ and each radially adjoin radial stops  46   f  (of which only the radial stop of the one locking element  4   f  was marked) of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ in the two planes. This contact bearing is caused by wedges  5   f ,  5   f ′ which are guided in diametrically arranged slit-like slide guides  20   f ,  20   f ′ of the follow disc  2   f  by means of wedge guides  52   f ,  52   f ′ and adjoin with their wedge faces  5   if ,  5   if ′ on both sides the side contact bearing faces of the scissor arms  81   f ,  82   f.    
         [0065]    Springs  7   f ,  7   f ′ between the displacement housing  10  and the end faces of the wedges  5   f ,  5   f ′ facing the displacement housing  10  press the wedges  5   f ,  5   f ′ in the direction of the output axis  30  and thus cause the scissor arms  81   f ,  82   f  to spread apart so that these adjoin with their angled ends against the radial stops  46   f  of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″. For this purpose the springs  7   f ,  7   f ′ are formed only strong enough so that they spread the scissor arms  81   f ,  82   f  apart so that their angled ends bear against the radial stops  46   f  of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ but not so the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ can turn against the action of the locking element springs  6   f ,  6   f′.    
         [0066]    The slide guides  20   f ,  20   f ′ of the follower disc  2   f  for housing the wedge guides  52   f ,  52   f ′ have a rough or ribbed surface so that a self-locking bearing of the wedges  5   f ,  5   f ′ in the slide guides  20   f ,  20   f ′ of the follow disc  2   f  is ensured. On the other hand the contact bearing of the wedges  5   f ,  5   f ′ on the side contact bearing faces of the scissor arms  81   f ,  82   f  has no self-locking action, i.e. when the scissor arms  81   f ,  82   f  are compressed in the direction of the wedges  5   f ,  5   f ′ the wedges  5   f ,  5   f ′ would be pressed outwards, i.e. in the direction of the displacement housing  10 . The wedge faces  5   f ,  51   f ′ or the side contact bearing faces of the scissor arms  81   f ,  82   f  are preferably provided with a ball-shaped surface in order to produce a linear contact between the contact bearing faces of the scissor arms  81   f ,  82   f  and the wedge faces  51   f ,  51   f ′ of the wedges  5   f ,  5   f′.    
         [0067]    The wedge angle α—as already explained in connection with FIGS.  1  to  4 —is measured so that the wedges  5   f ,  5   f ′ are not moved outwards when loaded, i.e. towards the displacement housing  10 .  
         [0068]    In the rest state the locking elements  4   f ,  4   f ′ and  4   f ′,  4   f ′″ are pressed apart under the action of the locking element springs  6   f ,  6   f ′ in each plane of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ and turned in the displacement housing  10  so far in the circumferential direction or circular until they adjoin both with their clamping faces  43   f ,  43   f ′ and  43   f ′,  43   f ′″ against the displacement housing  10  and against the points A and B or A′ and B′ respectively on the output element  3   f . If torque is exerted on the follower disc  2   f  against the output torque M recorded by the curved arrow, then the follower disc  2   f  presses through the slide guides  20   f ,  20   f ′ the wedge guides  52   f ,  52   f ′ and the wedge faces  51   f ′ against the scissor arm  81   f  which turns the locking elements  4   f  and  4   f ′″ unloaded on the output side in the drive direction before the drive torque acts through the window-shaped recesses  21   f ,  21   f ′ in the follower disc  2   f  on the claws  31   f ,  31   f ′ of the output element  3   f  and causes a corresponding rotary movement of the output element  3   f.    
         [0069]    If drive torque is exerted on the follower disc  2   f  in the direction of the output torque M then the other scissor arm  82   f  is loaded through the wedges  5   f ,  5   f ′ and turns the locking elements  4   f ′ and  4   f ′″ tensioned by the output torque.  
         [0070]    If as a result of torque on the output side the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ are loaded by the output element  3   f , then the radial stops  46   f  of the locking elements  4   f ,  4   f ′ and  4   f ″,  4   f ′″ are moved up to each other and displace the scissor arms  81   f ,  82   f  relative to each other accordingly. Since this movement must not be impeded by the wedges  5   f ,  5   f ′ the wedge angle α must be so great that the wedges  5   f ,  5   f ′ can move outwards without self locking.  
         [0071]    One embodiment with automatic play adjustment between a drive element  2   g , an output element  3   g  and a load torque lock  1   g  without scissor arms is shown in FIG. 9 in which the same function parts are marked with the same reference numerals as in FIG. 8 so that for the description and explanation of the function of these parts reference is made to the illustration of FIG. 8.  
         [0072]    In this embodiment the locking elements  4   g ,  4   g ′ and  4   g ″,  4   g ′″ of two superposed pairs of locking elements have window-shaped recesses  44  (of which only the recess of the one locking element  4   g  was marked) in which wedges  5   g ,  5   g ′ are mounted and adjoin with their wedge faces  51   g ,  51   g ′ against the one or other side face of the recesses  44  of the superposed locking elements  4   g ,  4   g ′ and  4   g ″,  4   g ′″. The wedges  5   g ,  5   g ′ which are likewise guided in slide guides  20   g ,  20   g ′ of the follower disc  2   g  by means of wedge guides  52   g ,  52   g ′ press with their wedge faces  51   g ,  51   g ′ directly against the locking elements  4   g ,  4   g ′ and  4   g ″,  4   g ′″ and thus cause an automatic play compensation as a result of tolerances and wear through the high surface pressure whilst simultaneously observing the torsion angle play which is required for functioning.  
         [0073]    [0073]FIG. 10 shows a plan view and FIG. 11 a longitudinal sectional view along the line XI-XI of FIG. 10 through a load torque lock  1   h  which corresponds to the load torque lock lf according to FIG. 8.  
         [0074]    In this arrangement instead of the springs  7   f ,  7   f ′ which are provided in FIG. 8 between the displacement housing  10  and the end sides of the wedges  5   h ,  5   h ′ facing the displacement housing two wire springs  7   h ,  7   h ′ are provided whose ends are supported in recesses  53   h ,  53   h ′ and  54   h ,  54   h ′ of the wedges  5   h ,  5   h ′. The ends of the wire springs  7   h ,  7   h ′ adjoin with force locking engagement against the walls, nearer the output axis  30 , of the recesses  53   h ,  53   h ′ and  54   h ,  54   h ′ of the wedges  5   h ,  5   h ′ guided with wedge guides  52   h ,  52   h ′ in slide guides of the follower disc  2   h  and cause a slight pretensioning of the wedges  5   h ,  5   h ′ in the direction of the output axis  30  so that the scissor arms  81   h ,  82   h  are pressed apart analogous with the arrangement and description according to FIG. 8 and their angled ends are brought to bear against the radial stops of the locking elements (not shown in further detail here).  
         [0075]    An alternative load torque lock  1   i  to the load torque lock  1   h  according to FIGS. 10 and 11 is shown in FIG. 12 and has instead of two wire springs for pretensioning the wedges  5   i ,  5   i ′ a yoke or formed spring  7   i  whose angled ends  71   i ,  72   i  are mounted in recesses  55   i ,  55   i ′ of the wedges  5   i ,  5   i ′ and cause the wedge faces of the wedges  5   i ,  5   i ′ to bear against the scissor arms  81   i ,  82   i  accordingly to compensate play. Also in this illustration of this embodiment elements having the same construction and same function are provided with the same reference numerals as with the embodiments already illustrated.  
         [0076]    Two further variations for an automatic play compensation between a drive element, an output element and a load torque lock with pairs of locking elements mounted one above the other in two planes are shown in FIGS.  13  to  16  each with the minimum and maximum play and with internal and external wedges.  
         [0077]    The load torque lock  1   k  according to FIGS. 13 and 14 has analogous with the embodiments already described two locking elements  4   k ,  4   k ′ and  4   k ″,  4   k ′″ mounted in a displacement housing  10  in superposed planes of the load torque lock  1   k  as well as a drive element (not shown in further detail) whose slide guides  20   k ,  20   k ′ are connected in positive locking engagement with the wedge guides  52   k ,  52   k ′ of two wedges  5   k ,  5   k ′, and an output element  3   k  which is rotatable about an output axis  30 .  
         [0078]    The wedges  5   k ,  5   k ′ are mounted between opposite expanding faces  41   k  to  41   k ′ of the locking elements  4   k ,  4   k ′ and  4   k ″,  4   k ′″ of each plane wherein the expanding faces  41   k  to  41   k ′″ open towards the displacement housing  10  and the wedge faces  51   k ,  51   k ′ adapted to the opening of the expanding faces  41   k  to  41   k ′″ extend out towards the displacement housing  10  so that the wedges  5   k ,  5   k ′ are mounted “on the outside”. The opening angles of the expanding faces  41   k ,  41   k ′ and  41   k ″,  41   k ′″ and of the wedge faces  51   k ,  51   k ′ are thereby different from each other so that a linear bearing contact is provided between the expanding faces  41   k ,  41   k ′ and  41   k ″,  41   k ′″ and the wedge faces  51   k ,  51   k′.    
         [0079]    The locking elements  4   k ,  4   k ′ and  4   k ″,  4   k ′″ of each plane are pressed apart by locking element springs  6   k ,  6   k ′ mounted in recesses of the locking elements  4   k ,  4   k ′ so that—as previously described—the expanding faces  41   k ,  41   k ′ and  41   k ″,  41   k ′″ adjoin the wedge faces  51   k ,  51   k ′ and the clamping faces  43   k ,  43   k ′ and  43   k ″,  43   k ′″ adjoin the displacement housing  10 .  
         [0080]    Through the action of two wire, yoke or formed springs  7   k ,  7   k ′ the wedges  5   k ,  5   k ′ are pretensioned in the direction of the displacement housing  10  so that with maximum play the position of the wedges  5   k ,  5   k ′ shown in FIG. 13 is produced whilst minimum play is characterised by the position of the wedges  5   k ,  5   k ′ shown in FIG. 14.  
         [0081]    The load torque lock  11  according to FIGS. 15 and 16 has analogous with the embodiment previously described two locking elements  41 ,  41 ′ and  41 ″,  41 ′″ mounted in a displacement housing  10  in superposed planes of the load torque lock  11  as well as a drive element (not shown in further detail) whose slide guides  20   l ,  20   l ′ are connected with positive locking engagement with the wedge guides  52   l ,  52   l ′ of two wedges  5   l ,  5   l ′, and an output element  3   l  rotatable about an output axis  30 .  
         [0082]    The wedges  5   l ,  5   l ′ are mounted between the opposing expanding faces  41   l  to  41   l ′″of the locking elements  4   l ,  4   l ′ and  4   l ′,  4   l ′″ of each plane wherein the expanding faces  41   l  to  41   l ′″ close towards the displacement housing  10  so that the wedges  5   l ,  5   l ′ are arranged “on the inside”, i.e. are enclosed by the expanding faces  41   l ,  41   l ′ and  41   l ″,  41   l ′″ of the brake elements  4   l ,  4   l ′ and  4   l ″,  4   l ′″. The locking elements  4   l ,  4   l ′ and  4   l ″,  4   l ′″ of each plane are pressed apart by locking element springs  6   l ,  6   l ′ mounted in recesses of the locking elements  4   l ,  4   l ′ and  4   l ″,  4   l ′″ so that—as previously described—the expanding faces  41   l ,  41   l ′ and  41   l ″,  41   l ′″ bear against the wedge faces  51   l ,  51   l ′ and the clamping faces  43   l ,  43   l ′ and  43   l ″,  43   l ′″ bear against the displacement housing  10 .  
         [0083]    The opening angles of the expanding faces  41   l ,  41   l ′ and  41   l ″,  41   l ′″ and of the wedge faces  51   l ,  51   l ′ are also here different from each other so that a linear contact is produced between the expanding faces  41   l ,  41   l ′ and  41   l ″,  41   l ′″ and the wedge faces  51   l ,  51   l′.    
         [0084]    The wedges  5   l ,  5   l ′ are pretensioned in the direction of the displacement housing  10  under the effect of two wire, yoke or form springs  71 ,  71 ′ so that with maximum play the position of the wedges  5   l ,  5   l ′ shown in FIG. 15 is produced whilst minimum play is characterised by the position of the wedges  5   l ,  5   l ′ shown in FIG. 16.  
         [0085]    Further variations for compensating play between a drive element, an output element and a load torque lock with pairs of locking elements mounted one above the other in two planes are shown diagrammatically in FIGS. 17 and 18.  
         [0086]    The part of a displacement device shown in FIG. 17 having a load torque lock  1   m  has analogous with the embodiments illustrated previously, two pairs of locking elements  4   m ,  4   m ′ mounted in a displacement housing  10  in superposed planes of the load torque-lock  1   m  as well as a rod-like drive element  2   m  and an output element  3   m  which encloses the rod-like drive element  2   m  with play.  
         [0087]    A locking element spring  6   m  is mounted at one end of the locking elements  4   m ,  4   m ′ between opposing expanding faces  4   lm ,  4   lm ′ of the locking elements  4   m ,  4   m ′ of each plane and brings both the clamping faces  43   m ,  43   m ′ of the locking elements  4   m ,  4   m ′ to bear against the displacement housing  10  and also through rotation of the locking elements  4   m ,  4   m ′ in the displacement housing  10  to bear against the contact bearing points A, B of the output element  3   m . The clamping faces  43   m ,  43   m , thereby adjoin the displacement housing  10  and through rotation of the locking elements  4   m ,  4   m ′ in the circumferential direction adjoin the stop points A and B on the output element  3   m.    
         [0088]    A wedge  5   m  is provided as a play compensating device and with its wedge faces  5   lm ,  5   lm ′tapering towards the displacement housing  10  adjoins the expanding faces  43   m ,  43   m ′ of the locking elements  4   m ,  4   m ′ and is pushed through a bore  52   m  to guide the wedge  5   m  on to the rod-like drive element  2   m  and is guided through same. A spring  7   m  is mounted between the end face of the wedge  5   m  remote from the displacement housing  10  and the end face of the output element  3   m  facing this said end face, the spring  7   m  pretensioning the wedge  5   m  in the direction of the expanding faces  51   m ,  51   m ′ and thus as a result of the configuration of the facing expanding faces  41   m ,  41   m ′ of the locking element  4   m ,  4   m ′ as well as of the wedge faces  51   m ,  51   m ′ of the wedge.  5   m  causes the locking elements  4   m ,  4   m ′ to slide apart in parallel and bear radially in each plane against the displacement housing  10 .  
         [0089]    The wedge faces  51   m ,  51   m ′ of the wedge  5   m  thus adjoin the expanding faces  41   m ,  41   m ′ of the locking elements  4   m ,  4   m ′ so that no self-locking action is produced between the locking elements  4   m ,  4   m ′ and the wedge  5   m . The wedge  5   m  is pressed back against the spring  7   m  under the effect of the locking element springs  6   m  and the resulting rotation of the locking elements  4   m ,  4   m ′ in the displacement housing  10 .  
         [0090]    If a drive torque is exerted on the drive element  2   m  against the output torque then this drive torque is first transferred to the wedge  5   m  since sufficient play is provided between the drive element  2   m  and the output element  3   m . The wedge  5   m  is pressed with self-locking action by the drive element  2   m  against the locking elements  4   m ,  4   m ′ and lifts the clamping faces  43   m ,  43   m ′ of the locking elements  4   m ,  4   m ′ slightly away from their bearing against the displacement housing  10  so that the friction contact is eliminated or reduced and the drive element  2   m  as a result of overcoming the play between the drive element  2   m  and output element  3   m  comes to bear against the inner faces of the output element  3   m . The drive torque is thereby transferred directly to the output element  3   m  in the rotary direction of the drive torque.  
         [0091]    If however torque is exerted on the output element  3   m  then the output element  3   m  transfers, as a result of its bearing contact against points A and B on the locking elements  4   m ,  4   m ′, the torque to the locking elements  4   m ,  4   m ′ whereby the bearing contact of the clamping faces  43   m ,  43   m ′ against the displacement housing  10  is intensified and thus torque transfer from the output element  3   m  to the drive element  2   m  is blocked.  
         [0092]    [0092]FIG. 18 shows an arrangement which is substantially similar to the embodiment according to FIG. 17. As opposed to the embodiment according to FIG. 17 however with the load torque lock in according to FIG. 18 the wedge  5   n  is provided with a recess  52   n  into which an end of the drive element  2   n  engages and thereby guides the wedge  5   n , and the wedge faces  51   n ,  51   n ′ thereby expand towards the displacement housing  10  and adjoin expanding faces  41   n ,  41   n ′ of the locking elements  4   n ,  4   n ′ which open correspondingly towards the displacement housing, i.e. the distance between the expanding faces  41   n ,  41   n ′ of the locking elements  4   n ,  4   n ′ increases towards the displacement housing  10 . The expanding faces  41   n ,  41   n ′ are adjoined by the wedge faces  51   n ,  51   n ′ of the wedge  5   n  under the action of a weak spring  7   n  which is mounted between the displacement housing  10  and the end face of the wedge  7   n  facing the displacement housing  10 .  
         [0093]    Analogous with the arrangement according to FIG. 17 the wedge faces  51   n ,  51   n ′ of the wedge  5   n  thus adjoin the expanding faces  41   n ,  41   n ′ of the locking elements  4   n ,  4   n ′ so that no self locking action is produced between the locking elements  4   n ,  4   n ′ and the wedge  7   n.  The wedge  5   n  is pressed back against the spring  7   n  under the action of the locking element spring  6   n  with the resulting rotation of the locking elements  4   n ,  4   n ′ in the displacement housing  10 .  
         [0094]    If a drive torque is exerted against the output torque onto the drive element  2   n  then this drive torque is first transferred to the wedge  5   n  since sufficient play is provided between the drive element  2   n  and the output element  3   n . The wedge  5   n  is pressed with self locking action by the drive element  2   n  against the locking elements  4   n ,  4   n ′ and lifts the clamping faces  43   n ,  43   n ′ of the locking elements  4   n ,  4   n ′ slightly away from their bearing contact against the displacement housing  10  so that the friction connection is lifted or reduced and the drive element  2   n  as a result of overcoming the play between the drive element  2   n  and the output element  3   n  comes to bear against the inside faces of the output element  3   n  whereby the drive torque is transferred directly to the output element  3   n  in the rotary direction of the drive torque.  
         [0095]    If however torque is exerted on the output element  3   n  then the output element  3   n  as a result of the contact bearing of the output element  3   n  and locking elements  4   n ,  4   n ′ against the points A and B transfers the torque to the locking elements  4   n ,  4   n ′ whose clamping faces  43   n ,  43   n ′ intensify their contact bearing against the displacement housing  10  so that torque transfer from the output element  3   n  to the drive element  2   n  is blocked.  
         [0096]    All the displacement devices described above have the common basic function according to which with drive torque acting in the direction of the output torque the lock caused by the locking element is lifted but remains latently active so that an immediate locking takes place when the drive torque is lifted. If however the drive torque acts against the output torque then the lock is lifted and the drive torque is introduced into the output. A slight lifting or circular rotation of the locking element thereby takes place and then an immediate renewed bearing contact against the displacement housing.