Abstract:
An adjustment mechanism for adjustable pieces of furniture is provided with a coupling including a transmission and sub-coupling structure, where the transmission and sub-coupling structure is constructed in such a way that at least one secondary transmission is always adjusted whether one primary transmission is actuated or whether the another primary transmission is actuated. At least two catch decouplers are provided in such a way that when the at least one primary transmission is adjusted, and disengaged by an adjustment of an associated actuator, the transmission and sub-coupling structure is always also entrained and adjusted, while one of the catch decouplers cooperates with the transmission and sub-coupling structure in such a way that the adjusting or pivoting transmission and sub-coupling structure leaves a second secondary transmission and/or the second actuator unchanged in position.

Description:
This application is claims priority to EP Application No. 09007082.2 filed 27 May 2009, the entire contents of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a coupling means, in particular for a furniture adjustment means. 
     An adjustable piece of furniture is known from EP 0 572 770 B1 and EP 1 159 887 B1, for example. Each of these two prior publications discloses a folding table, comprising T-shaped bases which are arranged at the end face and support a work surface or table top. This table top is conventionally oriented horizontally in a work and use position. 
     This work surface or table top can be pivoted between the conventional, approximately horizontally oriented work and use position and an approximately vertical storage position. 
     A locking mechanism is therefore provided as an adjustment means and fixes the work surface in the conventional, approximately horizontal use position thereof. By contrast, if the work surface is to be pivoted into a space-saving storage position, the locking mechanism is actuated in such a way that said surface can be pivoted about a horizontal pivot axis into the approximately horizontal storage position thereof. 
     The locking mechanism can for example be disengaged using an actuation means, which is arranged of the underside of the table top directly alongside the longitudinal edge. If the table top is for example to be pivotable about a horizontal pivot axis in both directions, in such a way that the table top can be pivoted into the storage position thereof at any time independent of from which side a user approaches the table, it is expedient to provide an actuation and disengagement means, with which the locking mechanism can be released, alongside each of the two longitudinal sides of the table top on the underside. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide an improved adjustment means, in particular for an adjustable piece of furniture. 
     In the context of the invention, a coupling means for adjusting pieces of furniture or furniture parts, in particular a locking and release means for pivotable table tops is provided, and may comprise a plurality of actuation means, for example two actuation means. In particular for a pivotable table top, at least one actuation means for unlocking the table top is provided on the underside of the table top along each longitudinal side of the table top, and can only be pulled into the disengagement and released position against the force of a spring means for example. Thus, the locking means is finally adjusted into the released position, in such a way that the table top can be pivoted for example from the conventional, generally horizontal use position thereof into an approximately vertical storage position. 
     However, in the context of the invention a coupling means is now provided between the at least two actuation means and the locking means, and ensures that when an actuation and disengagement means is actuated, the further actuation or disengagement means provided in each case on the opposite table top underside alongside the longitudinal edge is not also moved or adjusted. 
     For this purpose, in the context of the invention the coupling means is constructed in such a way that when only one actuation means out of at least two provided actuation means is adjusted, only the adjustment brought about by this one actuation means is ever passed on via the coupling means according to the invention to the at least one or preferably two furniture adjustment means, preferably in the form of a locking and release means, the second actuation means which is not adjusted remaining in the starting position thereof, in effect being decoupled. 
     According to the invention, this can be provided in that when one of the two actuation means is actuated via the so-called primary transmission means which is thus adjusted, the coupling means is acted on in such a way that the secondary transmission means, leading from the coupling means to the at least one furniture adjustment means, is also adjusted and thus the other primary transmission means, proceeding from the other, non-adjusted actuation means and leading to the coupling means, remains unadjusted. 
     This concept can be provided by various measures within the scope of the invention. 
     In a preferred embodiment of the invention, this is achieved by two slides, which are coupled to one another by a transmission and coupling means which acts between them. If an actuation and disengagement means is actuated, this causes one slide to be adjusted against the force of a spring means, for example in the longitudinal direction, and causes the secondary transmission means, which engages on said slide for example and is connected to the adjustment or locking means of the table for example, also to be adjusted. The opposite, second slide is also adjusted via the coupling means, and comprises for example a catch decoupling means having a sufficiently long release path that ultimately the second primary transmission means (which thus leads to the second actuation means) is not also adjusted but remains in the starting position thereof without any change. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in greater detail in the following by way of embodiments, in which, specifically: 
         FIG. 1   a  is an end view of a folding table according to the invention; 
         FIG. 1   b  is a longitudinal side view of a detail of the folding table according to the invention, with the support column arrangement arranged at the right-hand end of the table; 
         FIG. 2  is an end view, comparable to  FIG. 1 , of the table according to the invention, in which the table top has been pivoted to the right into the storage position thereof; 
         FIG. 3   a  is an end view comparable to  FIG. 3   a , but in which the table top is pivoted into the opposite storage position; 
         FIG. 3   b  is a rear view of part of the folding table shown in  FIG. 3   a  with the work surface folded into the storage position; 
         FIG. 4  is a three-dimensional view of a detail of a two-armed table top support having an associated hollow shaft and a mounted bevel gear fixed in rotation therewith, adjacent to a cable channel; 
         FIG. 5  is a three-dimensional schematic view of a bracing and supporting head with associated ratchet wheel and fixed axle; 
         FIG. 6  is an exploded view of all of the relevant parts of the coupling means according to the invention; 
         FIG. 7  is an enlarged detail of the coupling means according to the invention, omitting the coupling housing lid and other components: 
         FIG. 8  is a view corresponding to  FIG. 7 , in which further components associated with the coupling means are also incorporated, such as two parallel slides and a coupling transmission means; 
         FIG. 9  is a detail of the coupling means according to the invention and an actuation member attached to said coupling means as well as a locking and release means, in the basic, starting position, which is actuated via the coupling means; 
         FIG. 10  is a view corresponding to  FIG. 9 , in which the coupling means is located in an intermediate position; 
         FIG. 11  is another further view corresponding to  FIGS. 9 and 10 , but with the coupling means fully pivoted in an end position opposite the starting position, with the locking means released; 
         FIG. 12  is a schematic view of a further basic example of a configuration according to the invention of a coupling means according to the invention in the basic, starting position thereof; and 
         FIG. 13  is a view corresponding to  FIG. 12  with the coupling means adjusted into the two end positions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1   a  shows for example the right-hand end face  1   a  of a folding table  1 .  FIG. 1   b  is the right-hand part of one longitudinal side  1   b  of the table  1 , showing the support means  3  which is arranged on the right in this view. 
     It can be seen from the drawings that the folding table  1  comprises an upwards-facing table top  5 , which in  FIGS. 1   a  and  1   b  is located in the generally horizontally oriented work position thereof. 
     The support means  3  is provided at each of the two opposite end faces  1   a  and in the embodiment shown comprises a respective support column  7 , which transitions downwards into a support base  9 , which comprises support base portions  9   a  and  9   b  projecting on either side of the support column  7 . 
     A roller arrangement  11  is provided on each of the opposite ends of the support bases  9  and is conventionally provided with a fixing or releasing mechanism. This means that the folding table can be moved for various uses or storage positions without difficulty. In each desired work position it can be ensured, by actuating the locking mechanism integrated into the rollers, that the table is not moved accidentally. 
       FIG. 2  reproduces the right-hand end face  1   a  of the table as shown in  FIG. 1 , with the table top brought into the vertically extending storage position arranged on the right. 
     In  FIG. 3   a , by contrast with  FIG. 2 , the table top  5  has been brought into the opposite pivot position, and  FIG. 3   b  is a rear view, in the direction of the arrow III shown in  FIG. 3   a , of part of the underside  5   b  of the table top  5  when folded into the storage position. 
     So that the work surface can be folded into the storage position around a horizontal pivot axis  90  ( FIG. 3   b ) from either longitudinal side  1   b  of the folding table  1 , a disengagement and/or actuation mechanism  15  is provided on the two opposite longitudinal sides  1   a  of the folding table on the underside  5   b  of the table top  5  ( FIG. 3   b ). If this disengagement and/or actuation mechanism  15  is for example pulled in the direction of the arrow  15 ′ towards the adjacent longitudinal edge  5   d  of the table top  5  (specifically by gripping an associated handle portion on the actuation means  15 ), this releases a locking mechanism (described in greater detail below) in such a way that a table top located in the work position can then be folded into the storage position, pivoted through 90°, thereof or vice versa. It can be seen from  FIG. 3   b  that for example two actuation means  15   a  and  15   b  are provided, one actuation means being arranged alongside one longitudinal edge  5   d  and the other actuation means being arranged alongside the opposite longitudinal edge  5   d  on the underside of the table top, in such a way that it is possible from either side to grip a corresponding actuation means  15  and thus to carry out the desired adjustment. 
     As can be seen from the drawings, a two-armed table top support  17 , extending parallel to the end face  5   c  of the table top  5  in the embodiment shown, is provided offset inwardly on the underside  5   b  of the table top  5 , in each case in the end face region of the end face  5   c  of the table top  5 , and is screwed onto the underside  5   b  of the table top  5  using screws for example. 
     A trough  19  is fixed to the underside of the table top, between the two two-armed table top supports  17  arranged alongside the end edges  5   c  of the table top  5 , and acts as a cable channel  19 ′. 
     The two-armed table top support  17  transitions—as can be seen in particular from the three-dimensional detail according to FIG.  4 —into a hollow shaft  17   a , which lies at a predetermined distance  18  below the upwards-facing construction plane  17   d  ( FIG. 1   a ) of the two-armed table top support  17 , the underside of the table top  5  being laid on said plane and fixed to the table top support. The aforementioned distance  18  between the underside of the table top  5  and the horizontal pivot or tilt axis  90  ( FIG. 3   b ) extending centrally through the hollow shaft  17   a  is of a sufficient size to travel past the respective stand means in the form of support columns, i.e. past the support columns  7 , when the table top  5  is pivoted into one of the two opposed storage positions (in which the table top is suspended oriented more or less vertically). 
     An axle  21  ( FIG. 5 ) engages in this hollow shaft  17   a  and is braced rigidly in a bracing head  23 , which is in turn supported directly on the upper end of the support column  7 . 
     This provides the possibility of the two-armed table top support  17  being pivoted together with the table top  5 , in each case around the non-rotating axle member  21  from the upwards-facing, approximately horizontal work position into one of the two mutually opposed storage positions, in which the work surface is oriented more or less in the vertical direction. 
     The table top is to be locked, at least in the single work position thereof, conventionally in the horizontal position, by a locking mechanism mentioned above, in such a way that pivoting is reliably prevented. 
     For this purpose, the locking mechanism comprises a furniture adjustment means  141 , in the present embodiment specifically in the form of a locking and release means  143 , which comprises on the one hand a pivotable locking and/or retaining means  151  having a catch pin  147 , and on the other hand a catch means  153 , which is formed as a locking disc  153 ′ in the present embodiment. 
     As can be seen from  FIG. 5 , the locking disc  153 ′ comprises three catch recesses  155 ,  156  and  157 , mutually offset in the circumferential direction, the first catch recess  155  being arranged in the vertically upwards-facing position and the catch recesses  156 ,  157  being arranged in the horizontal position, diametrically opposite relative to the horizontally oriented axle  21 . 
     In the embodiment shown, the locking disc  153 ′ is preferably screwed onto the bracing and retaining head  23  and thus held fixed axially and above all radially. The aforementioned recesses  155 ,  156 ,  157  which are offset in the circumferential direction may, depending on the catch position, be penetrated by an axial catch pin  147  ( FIG. 4 ), which is part of the actuation means  141  or is positioned thereon. The actuation means  141  having the locking and release means  143  and having the catch pin  147  which is formed or positioned thereon may for example be held in a recess  17 ′ of the two-armed table top support  17  so as to be displaceable and pivotable. 
     The following figures schematically show a coupling means  51  according to the invention for adjustable parts of pieces of furniture, for example for actuating a locking and release means  143  on a table with a pivotable table top  5 . 
     Thus,  FIG. 6  is a perspective, exploded view of an arrangement of the coupling means, together with an adjustment housing  53 , an adjustment housing lid  54 , and various adjustable components installed inside the housing. 
       FIGS. 7 to 9  follow, and show the basic construction, further to the exploded view of  FIG. 6 . 
     It can be seen from the drawings that the coupling means  51  in the embodiment shown comprises two adjustment slides  55 , i.e.  55   a  and  55   b , arranged mutually transversely offset and oriented mutually parallel, in the adjustment housing  53  shown in part (shown when open) in  FIG. 7 . 
     Each adjustment slide  55  is held biased, by a spring means  57 , into the single basic, starting position thereof, which it adopts when an actuation means  15  is not pulled out. Each spring means  57   a  or  57   b  is supported on the one hand against a stop  58   a  or  58   b  which is fixed to the housing and on the other hand against a stop  60   a  or  60   b  which moves together with the respective adjustment slide  55 , and is therefore biased towards compression. 
     As can be seen by comparing  FIG. 7  and  FIG. 8 , a parallel slide  59  is provided in the region of each adjustment slide  55   a ,  55   b , and comprises a longitudinal recess  62   a  or  62   b , a catch decoupling means  155   a  engaging in or penetrating through said recess, this catch decoupling means  155   a  in each case being formed on or fixed to the associated adjustment slide  55   a  or  55   b . In the embodiment shown, this catch decoupling means  155   a  or  155   b  is of a square shape in a plan view. 
     Each parallel slide  59   a  or  59   b  is guided by longitudinal displacement in the corresponding housing recess of the adjustment housing  53  and/or on the associated adjustment slide  55 , specifically taking into account the following particulars. 
     Each of the two parallel slides  59  is provided on the side facing the other with a toothed extension  63 , i.e. with ribs  63 , a transmission member  67  being arranged in the middle so as to be rotatable about a central axis  65  and also being equipped externally over part of the circumference thereof with a toothed extension  69 , one toothed extension  69   a  engaging, i.e. interlocking, with one toothed extension  63   a  on one parallel slide  59   a , and the other toothed extension  69   b  on the transmission member  67  engaging, i.e. interlocking, with the other toothed extension  63   b  on the other parallel slide  59   b.    
     As was shown previously in  FIG. 3   b , a first and a second actuation means  15   a  and  15   b  are provided, and are each connected to the coupling means  51  via a primary transmission means  131 , for example in the form of a Bowden cable (or another suitable means). In other words, one actuation means  15   a  is connected via one primary transmission means  131   a  and the second actuation means  15   b  is connected via the second primary transmission means  131   b  to two different points on the coupling means. 
     It can thus be seen from the plan view of  FIGS. 7 and 8  that the primary transmission means  131   a  coming from the first actuation member  15   a  and leading to one adjustment slide  55   a  leads via the associated entrance face  71   a  on the adjustment housing  51  to this one adjustment slide  55   a  and is rigidly braced to a bracing point  155   a  located there. The second actuation means  15   b  is connected to the second adjustment slide  55   b  via the second transmission means  131   b  coming through the second entrance face  71   b , specifically at a second bracing point  155   b , these bracing points  155  forming the so-called catch decoupling means  155  in the embodiment shown. 
     As can be seen from the remaining  FIGS. 9 ,  10  and  11 , the coupling means  51 , i.e. the parallel slides  55   a  and  55   b , are connected via a further, i.e. secondary transmission means  133  to an associated furniture adjustment means  141 , in the form of a locking and release means  143  in the embodiment shown. Thus, the remaining  FIGS. 9 ,  10  and  11  show the coupling means  51 , at least together with one actuation means  15   a  and the associated primary transmission means  131   a , the second primary transmission means  131   b  coming from the second actuation means  15   b  only being shown in part. The associated secondary transmission means  133   a  and  133   b  now engage on the aforementioned, mutually opposed faces of the associated parallel slides  59   a ,  59   b , and lead both to the locking and release means  143  leading along one end face of the adjustable table and to a second locking and release means  143  provided on the opposite end face of the table having the adjustable table top ( FIGS. 9 to 11  only showing or indicating the locking and release means  143  provided on one end face). 
     In other words, the secondary transmission means  133   a  and  133   b  are fixed to the relevant associated parallel slide  59   a  or  59   b  at fixing points  134   a  and  134   b.    
     The operation will be discussed in greater detail in the following. 
     If for example one actuation means  15   a  on the underside of the table top alongside the respective longitudinal side  5   d  is pulled in the direction of the arrow  15 ′, then the associated transmission means  131   a  (in this case in the form of a Bowden cable, although it is of course also possible for a different force transmission and adjustment means to be provided) is also pulled out, in such a way that the associated adjustment slide  55   a  is adjusted against the force of the spring means  57 ,  57   a  towards the opposite adjustment position thereof in the adjustment housing  53 , i.e. on the adjustment path  75   a  thereof in the direction of the arrow  175   a  ( FIG. 10 ). Because the catch  155   a , which penetrates through the aforementioned longitudinal recess  62   a  in the parallel slide  59   a , is formed on the adjustment slide (the catch  155   a  simultaneously representing the bracing position  56   a  for the first actuation and disengagement means  131   a ), the parallel slide  59   a  is thus also adjusted via the adjustment slide  55   a  from the starting position thereof shown in  FIG. 9  through the intermediate position thereof shown in  FIG. 10  into the end position thereof shown in  FIG. 11 . The parallel slide is also entrained because the catch  155   a  penetrates through the longitudinal recess  62   a  at the end of said longitudinal recess  62   a  and, when tensioned via the aforementioned actuation and disengagement means  131   a , is supported directly against the delimiting stop of the longitudinal recess  60   a  and thus also adjusts the parallel slide  59   a.    
     Because the adjustment and transmission means  133   a , which leads to one locking and release means  143  on one end face of the table, engages on the opposite end of the parallel slide  59 , it accordingly adjusts a locking mechanism (for example a locking lever described further below) from the locked position into the released position thereof. 
     However, it can also be seen from  FIGS. 9 and 10  that the adjustment (i.e. displacement) of the parallel slide  59   a , via the toothed extensions  63  formed internally thereon, also rotates the transmission means  67  which on the opposite side thereof is in engagement with the further parallel slide  59   b  via the toothed engagement which is present there. In this way, the second parallel slide  59   b  located on the opposite side is also adjusted into the opposite position, by contrast with  FIG. 6 , on the adjustment path  75   b  thereof. Because the second secondary transmission means  133   b , which leads to the second release and locking means  143  (which is provided on the end face, shown in  FIGS. 9 to 11 , of the table for unlocking and pivoting the table top), also engages on one end of this parallel slide  59   b  which is also adjusted, the two locking and release means  143  provided on the two opposite end faces of the table are only pivoted into the released position by pulling on an actuation member  15   a.    
     However, in this operation, despite the adjustment of the second parallel slide  59   b , this second adjustment slide  55   b  has been held undisplaced because of the force of the spring means  57   b  acting on it. This is also because the slit  62   b  in the second parallel slide  59   b  is sufficiently long that the catch decoupling means  155   b  projecting through this slit  59   b  can dip into this slit without interacting with the delimitations at the ends of the slit and remain undisplaced in the starting position thereof. Thus, the primary transmission means  131   b  which is connected to the second actuation means  15   b  via the second adjustment slide  55   b , and thus the associated actuation means  15 ,  15   b  are also not adjusted. 
     If the aforementioned first actuation means  15   a  is released again, then for example the spring means  57   a , which presses against the first adjustment slide  55   a  (for example also via a further spring means  146 , described further below, provided in the respective locking means), is displaced back into the starting position thereof shown in  FIG. 9 . Thus, the transmission means  67  is also pivoted back and the second parallel slide  59   b  is also guided back into the starting position thereof without the adjustment slide  55   b  moving. 
     If for example the second actuation means  15   b  were then actuated, starting as in  FIG. 9 , the parallel slide  59   b  on the left in  FIG. 9 , and via the catch  155   b  also the parallel slide  59   b , would thus be adjusted into the opposite adjustment position. In this way, the second secondary transmission means  133   b  is also pulled out directly and the locking and release means  143  connected thereby is adjusted into the released position. However, the first parallel slide  59   a  is also adjusted (now without the first adjustment slide  55   a  moving) into the pulled-out position thereof via the aforementioned transmission means  67  and the toothed engagement with the first parallel slide  59   a , also pulling out the secondary transmission means  133   a  which is connected to this parallel slide and which leads to the first locking and release means  143  and adjusts said means into the released position. 
     The advantage of this arrangement is thus still that when an actuation means is pulled out, the respective other actuation means  15  is always decoupled, i.e. not automatically also adjusted. 
     If, for example, only a single actuation means for furniture, for example only one locking and release means  143 , is provided, then only one adjustment transmission means  133  is positioned on the aforementioned adjustment means  51  and is for example connected either to the first parallel slide  59   a  or to the second parallel slide  59   b.    
     In the following, for completeness, one of a number of possible locking and release means  143  will be described briefly by way of the drawings. 
     As can be seen from  FIGS. 9 to 11 , the locking and release means  143  comprises for example a locking lever  143 ′, which is pivotable about an axis  144  and comprises a locking pin  147 , which latches into a fixed latch recess  55 , for example  55   a  ( FIG. 5 ), and is in particular acted on by the force of the aforementioned spring means  146 . 
     In the embodiment shown a lever transmission is also provided, i.e. a second locking lever  143 ′ of smaller dimensions is articulated about a further pivot axis  144 ′ in the region of the free end of the first locking lever  144 , the aforementioned adjustment and transmission means  133  then being positioned on this second locking lever  143 ′ and being connected to a respective associated first or second parallel slide  59   a ,  59   b . If, as mentioned above, the adjustment means  51  is accordingly adjusted by actuating an actuation means, then the two aforementioned adjustment transmission means  133   a ,  133   b  are pulled out and thereby the associated catch pins  147  are slid out from the respective catch recesses  55  by the two locking levers, in such a way that the table top support  17  is then freely pivotable together with the associated table top  5  about a horizontal axis  90 , for example into the approximately vertically oriented storage position thereof. If the actuation means is released again, then the respective catch pin is slid back into a catch recess  55  by the spring means  57  in the adjustment means  51  and also by the additional spring means  146  on the locking and release means  143 , if located in the direct extension of this catch pin  147  when the table top is correspondingly extended (in the horizontal or for example vertical direction). 
     A further, simplified principle for an adjustment means according to the invention is discussed by way of  FIGS. 12 and 13 . 
     From the basic drawing of  FIG. 12 , it can be seen that in this case too a transmission means  67  is provided for example in the form of a transmission means  67  pivotable about a central axis  65 , and said means will also sometimes be referred to as a coupling means  167  in the following. One of the two adjustment and transmission means  133   a  and  133   b  of this coupling means  167  which lead to the respective locking and release means  143  is in each case positioned on one of two opposite points, offset relative to the central axis  65 . 
     If for example the transmission means  131   a  shown at the top, leading to one actuation means  15   a , is now pulled, then the transmission and coupling means  67 ,  167  in the form of a double lever is also rotated anticlockwise from the position shown in  FIG. 12  into the position shown in  FIG. 13  by the catch  153   a , in this way, the two secondary transmission means  133   a  and  133   b  leading to the locking and release means  143  are also entrained and pulled out, since these adjustment and transmission means are rigidly connected to the transmission and coupling means  67 ,  167  at the fixing points  134   a  and  134   b.    
     It is thus preferred in each case for a relevant catch  155  or the relevant transmission means  131  also to be acted on by the force of one of the aforementioned spring means  57   a  and  57   b  (specifically, in the tension or compression direction depending on the support point, the spring means being biased under tension in the assignment according to  FIGS. 12 and 13 ), in such a way that when the actuation means  15  is released, this spring means pivots the entire adjustment means  51  back into the basic position thereof shown in  FIG. 12 . 
     However, for the adjustment process described, triggered by the actuated actuation means  15   a , it can be seen in the drawings, in the transition from  FIG. 12  to  FIG. 13 , that although the catch  153   a  (which is pulled out by the actuation means  15   a ) does pivot in correspondence with the transmission and coupling means  67 ,  167 , the opposite catch  153   b  simultaneously remains held in the starting position thereof by the spring means  57   b  thereof, since the opposite catch  153   b  is simultaneously decoupled from the rotated transmission and coupling means  67 ,  167 . In other words, the construction is of a type such that although the transmission and coupling means  67 ,  167  is rotated anticlockwise when the respective transmission means  131   a ,  131   b  is adjusted, rotation of the coupling means  67 ,  167  nevertheless retains the catch  155 , which is connected to the non-actuated transmission means  131   a  or  131   b , in an undisplaced manner in its shown starting position and in this way the respective second transmission means  131 , which is not acted on, and thus the associated second actuation means  15  remain in the starting position thereof. 
     In other words,  FIGS. 12 and 13  only show in a simplified manner that with tensile loading an entrainment effect is present to the extent that the force introduced via the actuation and disengagement means leads to pivoting of the coupling means and thus of the transmission means  67 ,  167 , but that this pivoting movement retains the non-actuated, non-adjusted transmission means  131  in an unpivoted manner in the starting position thereof because of the spring effect present thereon. 
     Further modifications are possible in this context. 
     In this embodiment too, if only one locking and release means  143  is disengaged, then only one of the two secondary transmission means  133   a  or  133   b  is omitted.