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FIELD OF THE INVENTION 
     The present invention relates to a pivotal motor-vehicle accessory. More particularly this invention concerns a fold-down armrest for a motor-vehicle seat. 
     BACKGROUND OF THE INVENTION 
     Pivotal accessories are employed, for example for armrests in vehicle interiors or for covers of stowage compartments, for example in center consoles. 
     Such armrests are known in the art in which the arm supports of the armrests can be pivoted between an essentially horizontal starting position and an approximately vertical raised position, the arm support being lockable in intermediate positions. The armrest can for example have a control device that pivoting between the starting position and the raised end position allows the arm support to be pivoted to a first pivot position, yet prevents any pivot movement in the opposite pivot direction. Once the upper position has been reached, the latch is operated by the control device so as to enable the arm support to be pivoted freely in both directions until the starting position has been reached. Once the starting position has been reached, the latch is once again operated so as to allow the arm support to pivot only in one pivot direction. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved pivotal motor-vehicle accessory. 
     Another object is the provision of such an improved pivotal motor-vehicle accessory that overcomes the above-given disadvantages, in particular that is provided with a latch which is simple to produce but nevertheless ensures a high degree of functional reliability. 
     SUMMARY OF THE INVENTION 
     In combination with a motor-vehicle accessory having a pivotal element that can pivot about an axis on a generally fixed is support element, a mechanism has according to the invention an extension on one of the elements offset from the axis and projecting angularly of the axis, and a brake on the other of the elements having a pair of brake shoes flanking the extension and shiftable between a clamping position gripping the element and preventing movement of the element relative to the brake in at least one angular direction and a release position permitting movement of the element relative to the brake both in and against the one direction. 
     In other words, with the device according to the invention, a pivotal element is pivotally attached to a vehicle-fixed bracket. A latch allows pivoting of the pivotal element between a starting position and a raised end position, and can be locked at different positions. The latch has a locking means including at least one locking extension and a second locking means including at least one brake shoe. The brake shoes are able to move between a clamping position and a release position. The locking extension is, for example associated with the pivotal element, while the brake shoes are associated with the bracket or support element. The locking extension can be clamped in place in the clamping position by the brake shoes so as to prevent any movement by the pivotal element. The pivotal element is able to move when the brake shoe is in the release position. Friction can be applied by the brake shoes to faces of the locking extension, which frictional force acts a right angle to the direction of motion of the locking extension. 
     In a first embodiment, the latch has a control device by which the brake shoe can be moved indirectly or directly to the release position and/or to the clamping position. Control can be effected, for example as a function of the position of the pivotal element. Alternatively, control can be effected by a switch that can be actuated manually. 
     In another embodiment, the control device has first control means that are associated with the first locking means, and second control means are associated with the second locking means. At specific positions of the pivotal element, for example in the starting position and/or the raised end position, the first control means can for example interact with the second control means and effect an adjustment of the latch. 
     In another embodiment, the first control means comprise at least one control cam by which the brake shoe is able to move to the clamping position and/or to the release position. The control cam is attached to the pivotal element, for example in such a way that an adjustment of the latch is initiated in certain positions of the pivotal element, such as for example in the starting position and/or the raised end position. 
     In another embodiment of the invention, the brake shoe is biased by a spring into the clamping position and/or into the release position. The spring device is, for example able to move between a first position and a second position. In the second position, the spring forces the brake shoe into the clamping position. In the first position, the brake shoe is held in the release position. 
     In another embodiment, the spring device can be moved by an adjustment device to the first position and/or the second position, and can be held in the first position or the second position. The adjustment device can, for example be actuated by the first control means, for example, by at least one cam. The cam is, for example permanently attached to the pivotal element. The adjustment device is composed, for example of an adjustment lever. The adjustment lever is provided, for example, in the form of a multi-arm lever. One lever arm interacts, for example with the cam, while a second lever arm functions to operate the spring device. 
     In another embodiment, the brake shoe includes a friction face that interacts with the braking face of the locking extension, and a control face that interacts with the face of a support element. This embodiment enables the brake shoe, first of all, to be provided with the optimal frictional properties for interacting with the locking extension, and, second, to be provided with a specific motion characteristics. 
     In another embodiment of the invention, a coefficient of friction is provided between the friction face and the braking face that is greater than that between the control face and the braking face of the support element. This embodiment ensures that the brake shoe can move easily between the clamping position and the release position, and that the locking extension is locked by the force of friction in the clamping position. 
     In another embodiment, the control face and the face of the support element create at least one first pair of oblique faces that initiates a movement of the brake shoe in the clamping direction in response to a movement by the brake shoe relative to the face of the support housing in a first direction. The oblique faces can be provided, for example at a 45° angle relative to the first direction, with the result that the movement of the brake shoe in the first direction causes a simultaneous movement perpendicular to the first direction. 
     In another embodiment, the control face and the face of the support element create at least one second pair of oblique faces that causes a movement of the brake shoe opposite to the clamping direction in response to a movement of the brake shoe relative to the face of the support element in a second direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which: 
         FIG. 1  is a perspective view of a motor-vehicle center console according to the invention; 
         FIG. 2  is a rear view of the console, taken in the direction of arrow II of  FIG. 3 ; 
         FIG. 3  is a side view of the console, with the mounting arm and latch shown in faint linework; 
         FIG. 4  is a top view of the console, taken in the direction of arrow IV of  FIG. 3 ; 
         FIG. 5  is a side view of one of the mounting arms a lower starting end position relative to the respective fixed brake; 
         FIG. 5   a  is a top view taken in the direction of arrow Va of  FIG. 5 ; 
         FIG. 6  is a section taken along line VI-VI of  FIG. 5 ; 
         FIG. 7  is a section taken along line VII-VII of  FIG. 5   a;    
         FIG. 8  is a perspective view of the mounting arm and brake as in  FIG. 5 ; 
         FIG. 9  is a view like  FIG. 5 , but in a first raised position of the arm relative to the brake; 
         FIG. 10  is a section taken along line X-X of  FIG. 9 ; 
         FIG. 11  is a section taken along line XI-XI of  FIG. 9 ; 
         FIG. 12  is a perspective view of the mounting arm and brake in the first raised position; 
         FIG. 13  is a side view of the mounting arm in a second raised position relative to the brake; 
         FIG. 14  is a section taken along line XIV-XIV of  FIG. 13 ; 
         FIG. 15  is a section taken along line XV-XV of  FIG. 14 ; 
         FIG. 16  is a side view of the mounting arm in an uppermost raised end position disengaged from the respective brake; 
         FIG. 17  is a side view of the mounting arm returned to a position close to the second raised end position; 
         FIG. 18  is a section taken view along the line XVIII-XVIII of  FIG. 17 ; 
         FIG. 19  is a section taken along the line XIX-XIX of  FIG. 18 ; 
         FIG. 20  is a perspective view of the mounting arm and the brake as in  FIG. 17 ; 
         FIG. 21  is a side view of the position after that of  FIG. 17 , with the arm in a position just before reassuming the starting position; 
         FIG. 22  is a section taken along the line XXII-XXII of  FIG. 21 ; 
         FIG. 23  is a section taken along the line XXIII-XXIII of  FIG. 22 ; 
         FIG. 24  a perspective view of the structure as in  FIG. 21 ; 
         FIG. 25  is a side view of the mounting arm and brake as in  FIG. 23 ; 
         FIG. 26  is an side view of a brake of the latch taken in the direction of arrow XXVI-XXVI of  FIG. 25 ; 
         FIG. 27  is a view taken in the direction of arrow XXVII of  FIG. 25 ; and 
         FIG. 28  is a perspective view of the brake. 
     
    
    
     DETAILED DESCRIPTION 
     As seen in  FIG. 1  an armrest  10  according to the invention is part of a motor-vehicle center console  11 . This armrest  10  has an arm support or cushion  12 , and parts  13   a  and  13   b  form a housing of the center console  11 . The arm support  12  in  FIG. 1  is a lower starting end position that enables the arm of a passenger of the vehicle to be supported on its upper surface  14 . The arm support  12  is permanently attached to two identical mounting arms  15   a  and  15   b  that are pivoted at their rear ends at a common axis a on the housing  13   a ,  13   b . The arms  15   a  and  15   b  coact respective brakes  16   a  and  16   b  fixed on the housing  13   a ,  13   b . A latch of the armrest  10  is formed by locking extension  17   a  and  17   b  of the mounting arms  15   a  and  15   b  and by the respective brakes  16   a  and  16   b.    
     In  FIGS. 2 through 4 , each mounting arm  15   a  and  15   b  is mounted on a respective support  18   a  and  18   b  of the housing  13   a ,  13   b  via a pivot joint G and is thereby pivotal about a horizontal pivot axis a normally extending perpendicular to the normal vehicle travel direction. Only the support  18   a  is shown in  FIG. 3 . Extensions  19   a  and  19   b  attached to the supports  18   a  and  18   b  carry the respective brakes  16   a  and  16   b  as also shown in  FIG. 4 . 
     Movement of the arm support  12  from the starting position to various raised pivot positions is controlled by the latch so that the arm support  12  can be locked in any of these pivot positions. The mounting arms  15   a  and  15   b  and the cushion  12  can thus be pivoted from the starting position of  FIGS. 5 through 8  in a direction u 1  until reaching a raised end position (see  FIG. 16 ). Although movement in the direction u 1  is possible, movement in the opposite angular direction u 2  is prevented by the latch in every intermediate position between the starting position and the uppermost raised end position. Only after reaching the uppermost raised end position can the arm support  12  be pivoted back in the return direction u 2 . Thus as the cushion or support  12  is raised, it can only pivot upward until it reaches the upper end position, whereupon it can be pivoted down again, but if released in any intermediate position, it will hold and cannot be pushed back down. 
       FIGS. 5-8  and  25 - 28  show the brake  16   a , which is identical to the brake  16   b . It has a U-shaped caliper  20  formed by side members  21   a  and  21   b  unitarily connected by a bight member  22 . The side members  21   a  and  21   b  extend approximately parallel to respective braking faces  23   a  and  23   b  of the respective locking extension  17   a . In addition, brake shoes  24   a  and  24   b  are provided that have respective back control faces  25   a  and  25   b  as well as front friction faces  26   a  and  26   b . The control faces  25   a  and  25   b  of the brake shoes  24   a  and  24   b  are of sawtooth shape with steep and shallow flanks and are complementary to respective faces  27   a  and  27   b  of the side members  21   a  and  21   b . The steep and shallow flanks of the sawteeth of the faces  25   a  and  25   b  are oriented relative to the directions u 1  and u 2  such that movement of the shoes  24   a  and  24   b  in the direction u 2  relative to the extension  17   a  cams the shoes  24   a  and  24   b  toward each other and into tighter engagement with the extension  17   a , while opposite movement in direction u 1  moves them apart and releases the extension  17   a.    
     More particularly as shown in  FIG. 18 , the brake shoe  24   a  has oblique faces  33   a  and  35   a  that interact with respective opposing faces  34   a  and  36   a  of the side member  21   a . Analogously, the brake shoe  24   b  has oblique faces  33   b  and  35   b , while side member  21   b  has respective opposing faces  34   b  and  36   b  that interact in the same way. The faces  33   a ,  34   a ,  35   a , and  36   a , as well as faces  33   b ,  34   b ,  35   b , and  36   b  form an angle β with the x axis. 
     This has the effect that a force acts in a direction v 1  in response to a force in direction x 1  on the brake shoe  24   a , while a force acts in a direction w 1  in response to a force in a direction x 2 . Analogously, a force in the direction x 1  on the brake shoe  24   b  results in a force in a direction v 2 , while a force in the direction x 2  results in a force in the direction w 2 . Directions x 1  and x 2  are parallel to an x axis, as well as to angular pivot directions u 1  and u 2 . When displaced in direction x 1 , the brake shoes  24   a  and  24   b  are moved outward and apart in the directions v 1 , v 2 , and when displaced in the direction x 2  the brake shoes  24   a  and  24   b  are moved inward in the directions w 1 , w 2 . 
     As shown in  FIGS. 5 ,  25 , and  26 , a first end of a spring  28   a  is attached by a fitting  37   a  to the side member  21   a , while a second end of the spring  28   a  is attached by a fitting  38   a  to the brake shoe  24   a . Analogously, a first end of another such spring  28   b  is attached by another such fitting  37   b  to the side member  21   b , while a second end of the other spring  28   b  is attached by another such fitting  38   b  to the brake shoe  24   b . Each brake shoe  24   a  and  24   b  is biased by the respective spring  28   a  or  28   b  in the direction x 2  whenever the respective spring  28   a  or  28   b  is in a second tensioned position. When the spring  28   a  or  28   b  is in a first untensioned position, the brake shoes  24   a  and  24   b  are held by the springs  28   a  and  28   b  in the release position. 
     Each side member  21   a  and  21   b  supports a respective control wheel  29   a  or  29   b  for pivoting about an axis a 2 . Cams  30  and  31  fixed on the extension  17   a  can rotate the control wheels  29   a  and  29   b  between a first position and a second position offset angularly about the axis a 2  by about 90°. In the first position of the control wheels  29   a  and  29   b  the respective springs  28   a  and  28   b  are moved by actuating arms  32  of the control wheels  29   a  and  29   b  to the second position. In the second position of the control wheels  29   a  and  29   b , the springs  28   a  and  28   b  can move to the first position by their own elastic restoring force. 
     When the arm support  12  moves from the starting position in the direction u 1 , the mounting arms  15   a  and  15   b  and the locking extensions  17   a  and  17   b , are also pivoted in the direction u 1  as indicated in  FIG. 5 . The springs  28  are in the second position, with the result that the brake shoes  24   a  and  24   b  are biased in the direction x 2 . In response to biasing in the direction x 2 , and thus the biasing toward each other of the brake shoes  24   a  and  24   b  associated therewith in the direction w 1  or w 2 , the friction faces  26  come into contact with the braking faces  23   a  and  23   b.    
     When the locking extension  17   a , moves in the direction u 1 , the brake shoes  24   a  and  24   b  are biased oppositely to the biasing of the springs  28  in the direction x 1  opposite the clamping direction v 1 , v 2  due to the frictional locking between the approximately parallel friction faces  26  of the brake shoes  24   a  and  24   b , and the braking faces  23   a  and  23   b . There is thus no clamping of the locking extension  17   a , thereby enabling the arm support  12  to pivot freely in the direction u 1 . 
     Conversely, no movement in the direction u 2  is possible as long as the raised end position of the arm support  12  has not been reached. When the locking extensions  17   a  and  17   b  move in the direction u 2 , the brake shoes  24   a  and  24   b  are biased in the direction x 2  in the clamping direction w 1 , w 2  due to the frictional locking between the friction faces  26   a  and  26   b  of the brake shoes  24   a  and  24   b , and the braking faces  23   a  and  23   b . The locking extension  17   a  is clamped in place so strongly by the brake shoes  24   a  and  24   b  that no movement is possible by the arm support  12  in the direction u 2 . 
     When the mounting arms  15   a  and  15   b  are pivoted in the direction u 1 , the cam  30  comes into contact with an adjustment arm  39  of the control wheel  29  before reaching the raised end position (see  FIGS. 9 through 12 ) and moves the control wheel  29  to the second position, with the result that the spring  28   a  and  28   b  are reset to the first position and simultaneously move brake shoes  24   a  and  24   b  in direction x 1 , and in directions v 1 , v 2 , opposite the clamping direction. After reaching the raised end position, mounting arms  15   a  and  15   b  can be pivoted in the direction u 2 , and also once again in direction u 1  as long as the raised end position has not been reached. 
     When the mounting arms  15   a  and  15   b  are moved in the direction u 2 , the cam  31  comes into contact with the control wheel  29  just before reaching the raised end position (see  FIGS. 21 through 24 ). In response to additional movement by the mounting arms  15   a  and  15   b  in the direction u 2  to the end position, the control wheel  29  is pivoted by the cam  31  to the first position such that the springs  28   a  and  28   b  are moved to the second position and is held in this position by the control wheels  29   a  and  29   b . As a result, the directional locking mechanism is again activated, and the mounting arms  15   a  and  15   b  are able to move only in the direction u 1  until the raised end position has been reached.

Summary:
A motor-vehicle accessory having a pivotal element that can pivot about an axis on a generally fixed support element is provided with a mechanism having an extension on one of the elements offset from the axis and projecting angularly of the axis and a brake on the other of the elements. This brake has a pair of brake shoes flanking the extension and shiftable between a clamping position gripping the element and preventing movement of the element relative to the brake in at least one angular direction and a release position permitting movement of the element relative to the brake both in and against the one direction.