Abstract:
A pivoting fitting ( 1 ) comprises a first tab ( 2 ) and a second tab ( 3 ) which are mounted so as to be rotatable relative to each other about an axis ( 6 ), and a locking mechanism having at least one pawl ( 5 ) and toothing ( 4 ), wherein the pawl ( 5 ) can be engaged in the toothing in a plurality of positions and permits a pivoting movement of the first tab ( 2 ) with respect to the second tab ( 3 ) in a first direction and blocks movement in an opposing direction, and wherein at least one control element ( 14 ) is provided to disengage the at least one pawl ( 5 ) from the toothing ( 4 ) and then to pivot the first tab ( 2 ) with respect to the second tab ( 3 ) in the second direction through an angle, wherein the at least one pawl ( 5 ) is retained by a spring element ( 9 ) in a position engaged in the toothing ( 4 ), wherein the spring element ( 9 ) is at least partially made from an elastomer material. In this way, the pivoting fitting ( 1 ) can be pivoted with little noise.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to a pivoting fitting with a first tab and a second tab which are mounted so as to be rotatable relative to each other about a shaft, and a locking mechanism having at least one pawl and a toothing. 
     (2) Description of the Related Art 
     EP 1 284 447 discloses a pivoting fitting, in which a first tab can be pivoted relative to a second tab, wherein the tabs can be held on each other at a predetermined angular position by a latching or locking mechanism. The locking mechanism comprises two pawls which are pivotably mounted and are in engagement with a toothing via a spring element. The metallic spring element presses the pawls into the toothing and can be compressed in order to lift the pawls out of the toothing via a cam disc and to then pivot the tabs to an initial position. It is disadvantageous in this pivoting fitting that the latching of the pawls occurs in a comparatively loud way because the metallic spring presses the pawls with high force against the toothing, thus producing loud latching noises during the pivoting of the tabs which are perceived as disturbing. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to provide a pivoting fitting which enables low-noise latching of the locking mechanism during the twisting of the first tab relative to the second tab. 
     This object is achieved by a pivoting fitting with a first tab and a second tab which are mounted so as to be rotatable relative to each other about a shaft, and a locking mechanism having at least one pawl and a toothing, wherein the pawl can be latched in the toothing in a plurality of positions and permits a pivoting movement of the first tab with respect to the second tab in a first direction and blocks movement in an opposing second direction, and wherein at least one control element is provided in order to disengage the at least one pawl from the toothing, and then to pivot the first tab with respect to the second tab in the second direction through an angle, wherein the at least one pawl is retained by a spring element in a position engaged in the toothing, characterized in that the spring element is at least partly made from an elastomer material. 
     In accordance with the invention, the spring element for retaining the pawls in a latched position is made at least partly from an elastomer material. As a result, the spring forces can be arranged in a considerably lower manner than in a metallic spring element, which for reasons of tolerance compensation alone presses the pawls with a specific spring force to the latched position in order to ensure functional reliability of the locking or latching mechanism. This increases the latching noises during the pivoting of the tabs however, especially when the pawls are also made of a metallic material. The latching noises can be reduced considerably by the lower spring forces and the noise damping of the elastomer material during the pivoting of the first and the second tab. 
     In accordance with a preferred embodiment of the invention, a contact surface of the spring element, which rests on at least one pawl, consists of an elastomer material. The contact surface can be arranged adjacent to the toothing in order to provide good lever conditions. 
     The spring element is preferably made as a shaped body from an elastomer material. Synthetic materials, rubber mixtures or other elastic materials can be considered as materials for the spring element. An elastomer material with a Shore hardness of between 40 and 110, especially 60 to 90, more preferably between 70 and 85, is preferably used. 
     In order to keep the loading of the spring element at a low level, the spring element can be pivoted at least in sections with the control element. The spring element can comprise at least one hollow chamber which is surrounded by a flexible web. The flexible web can form a contact surface on the exterior side which rests on the pawl. 
     The spring element is only able to exert a spring force against the at least one pawl when the pawl is not arranged in a latched position on the toothing. The spring element can thus be set precisely in order to exert spring forces only when the pawl was slightly lifted from the latched position. This reduces the noise development because the pawl is pressed with only little force into the latched position by the spring element. Moreover, the elasticity of the spring element is maintained for a longer period of time in that a setting behaviour of the spring element is substantially avoided. 
     In accordance with a further embodiment, the control element brings the pawl out of engagement with the toothing in an end position, and the spring element is further relieved in order to then move the at least one pawl to an initial position on the toothing. The spring element is thus not unnecessarily loaded during the changeover of the pawl in order to bring said pawl out of engagement with the toothing. Instead, it can exert a spring force at first on the spring element and is then relieved via the control element. This leads to the advantage that the spring element is not unnecessarily compressed during such a changeover process, which could lead to a loss in the elastic behaviour. In fact, the spring element is relieved again by the control element and is moved back to an initial position. In said initial position, the spring element is tensioned against the pawl, which is then moved to a latched position on the toothing. This reduces the spring forces even during a movement of the at least one pawl from an end position to an initial position. 
     The control element can be arranged as a cam disc, wherein the spring element is supported with a section on the cam disc. The spring forces of the spring element preferably do not act substantially radially on the pawl, but substantially tangentially on said pawl. As a result, the spring element can be supported by a projection of the cam disc for example in order to exert sufficient spring forces on the pawl. 
     The pivoting fitting in accordance with the invention is especially used in furniture, e.g. in upholstered furniture, for armrests, headrests or other pivotable components. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention is explained below in closer detail by reference to an embodiment shown in the enclosed drawings, wherein: 
         FIGS. 1A to 1C  show several views of a pivoting fitting in accordance with the invention in a mounted position; 
         FIG. 2  shows a perspective exploded view of the pivoting fitting of  FIG. 1 ; 
         FIGS. 3A and 3B  show two views of the spring element of the pivoting fitting of  FIG. 1 ; 
         FIG. 4  shows a detailed view of the pivoting fitting of  FIG. 1  in an initial position; 
         FIG. 5  shows a view of the pivoting fitting of  FIG. 1  briefly before a changeover position, and 
         FIG. 6  shows a detailed view of the cam disc with a spring element. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A pivoting fitting  1  comprises a first tab  2  and a second tab  3 , which are pivotable relative to each other about a shaft  6 . The first tab  2  comprises a first part  20  and a second part  21  which are connected to each other on a section protruding radially from the shaft  6  and surround a central region of the second tab  3  in the region of the shaft  6 . A locking mechanism or a latching mechanism is provided within the middle region between the first part  20  and the second part  21 , which mechanism allows a movement of the first tab  2  relative to the second tab  3  in a first direction and blocks in a second direction. This blockage is lifted in an end position, and the tabs  2  and  3  can be moved back to an initial position. 
     As is shown in  FIG. 1C , the locking mechanism comprises two pawls  5 , which are rotatably mounted about a shaft  7 . The two shafts  7  are arranged spaced from the central shaft  6  for pivoting the tab. The second tab  3  comprises an annular toothing  4 , which faces the shaft  6  and can be brought into engagement with a toothing  8  on each of the pawls  5 . 
     In order to keep the pawls  5  in a latched position, a spring element  9  is provided in form of a shaped body which is made of an elastomer material and is rotatably mounted about the shaft  6 . The spring element  9  comprises a contact surface  10  on its radially outer region adjacent to the toothing  4 , which contact surface rests on a pawl. The shaped body substantially has the shape of an “8”, so that a respective contact surface  10  for acting on a pawl  5  is formed on opposite sides. A projection  17  is provided on the opposite side of the contact surface  10 , which projection is arranged on a cam disc. The force on the pawl  5  by the spring element  9  is thus applied substantially tangentially with respect to the shaft  6  or at a lower angle to the tangential, e.g. less than 30°, especially less than 15°. 
     In  FIG. 2 , the pivoting fitting  1  is shown in an exploded view. The shaft  6  is held on opposite sides of the tab  2  on the first part  20  and the second part  21 , and mounts both the cam disc  14  and also the spring element  9 . For this purpose, the spring element  9  comprises a middle opening  12  for leading through the shaft  6 . Two hollow chambers and  11  are further provided adjacent the opening  12 , which hollow chambers are surrounded by flexible webs. A projection  13  is integrally attached to a flexible web against the contact surface  10 , which projection engages in a recess of the cam disc  14  and is supported there on a projection  17 . The cam disc  14  comprises a central opening  15  for leading through the shaft  6  and comprises two slots  16 , which are penetrated by the shafts  7  on which the pawls  5  are rotatably mounted. The shafts  7  are retained on receivers  22  of the first part  20  and the second part  21 . Projections  18  are further formed on the cam disc  14 , which projections can be brought into engagement with the pawls  5  in order to release them from the latched position with engagement of the toothing  4  and to move them from an end position back to an initial position. 
     During pivoting of the first tab  2  relative to the second tab  3 , the spring element  9  is substantially only compressed when the pawl  5  is lifted when sliding over the teeth  8  of the toothing  4 , i.e. it is moved radially to the inside, so that the spring element  9  presses the pawls  5  back to a latched position. No spring forces, or only very low spring forces, act in the latched position, because the pawls  5  are retained in a self-locking manner in the toothing  4  as seen in the blocking direction. The first tab  2  can thus be pivoted relative to the second tab  3  from an initial position to an end position, where the cam disc  14  is then stopped by a limit stop and the pawls  5  are twisted relative to the cam disc  14 . A specific angular path is required for this process. The spring element  9  is compressed equally strongly on the contact surfaces  10  in the first half of the required angular path, as in a conventional switching process in the working region of the pivoting fitting  1 . After exceeding half the angular path and a further movement of the first tab  2  relative to the second tab  3 , the contact of the contact surfaces  10  to the pawls  5  is interrupted simultaneously with the inward pivoting of the pawls  5 , and the spring element  9  is thus relieved. After reaching the end position, the first tab  2  is moved back relative to the second tab  3  from the end position to an initial position, wherein the pawls  5  are kept out of engagement. The mechanism for bringing the pawls  5  out of engagement can occur in different ways, e.g. as described in the document EP 1 284 447. 
     In the initial position, the spring element  9  is then pressed at first against the pawls  5  in order to then release the pawls  5 , so that they can be pivoted radially to the outside again and come into engagement with the toothing  4 . As a result, the loading of the spring element  9  during the changeover at the end position or the initial position is reduced to a minimum because the spring element is compressed only briefly. The spring element  9  remains substantially unloaded during the movement of the first tab  2  relative to the second tab  3  from the end position to the initial position. As a result, a setting behaviour of the elastomer material is thus substantially prevented. 
     The spring element  9  is shown in closer detail in  FIGS. 3A and 3B . The spring element  9  is produced as a shaped body made of an elastomer material, especially rubber or a synthetic material, e.g. foamed synthetic material. The Shore hardness of the material can lie in a range of between 70 and 90 Shore in order to exert sufficient spring forces on the pawls  5  without generating excessive latching noises during the pivoting of the tabs  2  and  3  relative to each other. The shaped body comprises two hollow chambers  11  which are surrounded by flexible webs on which the contact surfaces  10  and the projection  13  are formed. Other shapes of the spring element can be used in order to provide low-noise damping. 
       FIG. 4  shows the pivoting fitting of  FIGS. 1 and 2  in a detailed view in an initial position, wherein a cover for better view was omitted and invisible components were shown by way of a dashed line. The first tab  2  can be twisted from this initial position relative to the second tab  3  about the shaft  6 , wherein the pawls  5  are then rotated about the shaft  7  and then latch along the annular toothing  4  on the second tab  3 . The spring element  9  rests with the contact surface  10  on the pawls  5  in a region adjacent to the toothing  8 . The spring element  9  is supported via the projection  13  on the projection  17  of the cam disc  14 . 
     As is shown in  FIG. 6 , the projection  13  of the spring element  9  is used for suspending the spring element  9  in the recesses of the cam disc  14 . In this process, the projection  13  of the spring element  9  fixes the spring element  9  on the cam disc  14  through its shape and prevents axial slippage of the spring element  9  relative to the shaft  6 . This fixing also facilitates mounting. 
     The cam disc  14  rotates together with the first tab  2 , so that the radial protruding sections  24  can move toward the stops  23  on the second tab  3 . Depending on the arrangement of the stops  23 , the pivoting range of the first tab  2  relative to the second tab  3  can be set. As is shown in  FIGS. 4 and 5 , the tabs  2  and  3  are pivoted about a pivot angle of 90° relative to each other from an initial position to an end position, wherein further pivoting of the tab  2 , after reaching the position as shown in  FIG. 5 , leads to the consequence that as a result of the stops  43  the cam disc  14  ensures that the pawls  5  are lifted from the toothing  8  and the spring element  9  is relieved. For this purpose, the projections  18  act on the pawls  5  and lift them out of a latched position. At the same time, the spring element  9 , which is compressed at first, is relieved again. In this position, the tabs  2  and  3  can be moved back to the initial position, which is shown in  FIG. 4 . During the return movement, a radially protruding section  24  of the cam disc reaches a stop  23  on the second tab  3  and is stopped, so that the projection  18  of the cam disc no longer hold the pawls  5  out of engagement with the toothing  8  and they pivot to a latching position again. At the same time, the spring element  9  is moved back to the initial position shown in  FIG. 4 , in which the pawls  5  are held or slightly pretensioned in the latched position. 
     The spring element  9  can also have an enclosed shape instead of the hollow chambers  11 . Furthermore, the support of the spring element  9  can also occur by a tab instead of by a projection  13 , which tab is bent off from the cam disc  14 . 
     In a further embodiment (not shown), the spring element is integrally formed with the cam disc  14 , e.g. produced by a two-component injection moulding method. This reduces the number of components, which simplifies mounting. 
     Furthermore, the spring element can also be fixed to the pawls or arranged in an integral manner with said pawls. The spring element can be fixed as a soft component to the pawls. 
     In the illustrated embodiment, the pawls can be latched on a radial inner toothing of the tab  3 . Instead of such radial latching, it is also possible to provide axial latching, wherein in this case the toothing is made in an axial direction of the pivoting fitting relative to the shaft  6 . 
     It is further possible to arrange the control element  14  not as a separate component in form of a cam disc, but it can also be provided as a control section on a pawl or the spring element. This can also reduce the number of components on a pivoting fitting. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Pivoting fitting 
           2  Tab 
           3  Tab 
           4  Toothing 
           5  Pawl 
           6  Shaft 
           7  Shaft 
           8  Toothing 
           9  Spring element 
           10  Contact surface 
           11  Hollow chamber 
           12  Opening 
           13  Projection 
           14  Cam disc 
           15  Opening 
           16  Slot 
           17  Projection 
           18  Projection 
           20  Part 
           21  Part 
           22  Receiver 
           23  Stop 
           24  Radially protruding section