Patent Publication Number: US-2023157450-A1

Title: Furniture damper

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a furniture damper for dampening a movement of a movably-supported furniture part. the furniture damper comprises a damper housing, at least one fluid chamber arranged in the damper housing, a damping fluid arranged in the fluid chamber, and at least one piston displaceably supported within the fluid chamber and having at least one channel for the passage of the damping fluid. In addition, at least one switch element is configured to be moved, when a damping stroke is performed and below a predetermined threshold value of a pressure application to the piston, into a first position in which the at least one channel of the piston is at least partially covered by the switch element and wherein a first flow rate of the damping fluid streams through the at least one channel of the piston. 
     Moreover, the invention concerns a furniture fitting comprising at least one furniture damper of the type to be described. 
     Such furniture dampers are used, for example, for dampening a closing movement of movable furniture parts (such as drawers, doors or flaps), or for dampening a movement of movably-supported components of furniture fittings so as to prevent a noisy slamming and damages to the furniture parts. 
     The damping action of the furniture dampers is generated by the flow resistance of a damping fluid arranged in the damper housing. Upon a pressure application, the piston is displaced within the fluid chamber, and the damping fluid can stream from the high-pressure side to the low-pressure side through piston orifices and/or through a gap formed between the piston and the inner wall of the fluid chamber. 
     Upon an excessive pressure application to the piston, for example in the event of improper use, a so-called damper bouncing may occur. In such an overload case, the damping fluid can no longer stream through the piston or past the piston in a sufficient amount. The increased pressure can then no longer be dissipated by the damper, so that the piston and the piston rod fixed thereon come to an abrupt halt or bounce back. In an extreme case, the damper housing can burst due to the increased pressure, and the hydraulic damping fluid can leak out from the damper housing. 
     Overload safety devices for furniture dampers are well-known, for example as disclosed in AT 12 633 U1 and DE 20 2018 103 818 U1 to the present applicant. These overload safety devices usually include a ball pressurized by a spring, and the ball blocks an overload opening of the piston during normal operation (that is to say below a predetermined pressure application to the piston). In an overload case (that is to say above the predetermined pressure application to the piston), the ball unblocks the overload opening of the piston against the force of the spring. As a result, a fluid-conductive connection between the high-pressure side and the low-pressure side can be unblocked. By unblocking this fluid-conductive connection, an increased amount of damping fluid can be transferred from the high-pressure side to the low-pressure side. Therefore, the pressure within the furniture damper can be rapidly dissipated and a burst of the housing of the furniture damper can be prevented. 
     Such overload safety devices having a spring-loaded ball usually include an increased number of components. Therefore, the costs of the furniture damper in serial production of the furniture damper are also increased. 
     AT 15609 U1, DE 202 21 550 U1 and CN 101672339 A each disclose furniture dampers with a cylinder and a piston displaceable within the cylinder. The piston includes at least one channel for the passage of the damping fluid, and the channel of the piston can be blocked by a bendable or deformable lamella. Upon an increased pressure application, the channel of the piston can be increasingly blocked by the lamella so as to generate an increased braking force of the furniture damper. 
     AT 10 342 U1 discloses a furniture damper having a cylinder and a piston displaceable within the cylinder, and the piston includes at least one overload opening for the passage of a damping fluid. Moreover, a closure element configured to be displaced relative to the piston is provided, and the overload opening of the piston can be blocked by the closure element at the beginning of the damping stroke. Accordingly, during normal operation, the damping fluid can stream exclusively through an annular gap formed between the piston and an inner wall of the cylinder. Upon an increased pressure application, the closure element is radially widened so as to reduce the size the annular gap, thereby increasing the flow resistance for the piston. In an overload case, the closure element is radially widened to such an extent that the overload opening of the piston can be unblocked, and the pressure within the cylinder can be rapidly dissipated thereby. A drawback is the fact that the overload opening of the piston is immediately closed at the beginning of the damping stroke and that the damping fluid, during normal use, can only stream through the annular gap formed between the piston and the cylinder. As a result, there is the danger of a damper bouncing. In contrast, the overload opening of the piston is only unblocked in an overload case. Accordingly, the furniture damper, during operation, tends to have a dual switching behavior, and an adaption to the prevailing pressure conditions cannot be sufficiently provided. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to propose a furniture damper of the type mentioned in the introductory part, thereby avoiding the above-discussed drawbacks. 
     According to the invention, the at least one switch element is configured to be, when the damping stroke is performed and above the predetermined threshold value of the pressure application to the piston, moved from the first position into a second position in which the at least one channel of the piston is at least partially unblocked by the switch element and wherein a second flow rate of the damping fluid streams through the at least one channel of the piston, the second fluid rate of the damping fluid being larger than the first fluid rate. 
     In other words, the furniture damper includes at least one switch element configured to be moved between at least two positions. In a first position of the switch element, the at least one channel of the piston can be at least partially covered, whereby the damping action of the furniture damper can be controlled in a pressure-dependent manner. 
     In a second position, in contrast, the switch element serves as an overload-safety device. The switch element, in the second position, again unblocks the at least one channel upon an excessive pressure application to the piston in order to rapidly dissipate the arising pressure of the damping fluid in the damper housing, thereby preventing a damage to the damper housing. 
     Accordingly, it is no longer necessary to provide an additional overload safety device having a spring-loaded ball, because the switch element serves both as a pressure-dependent control and as an overload safety device. In this way, the number of components of the furniture damper can be reduced, the construction of the furniture damper can be simplified, and a cost-effective production can be provided. 
     A constructively simple embodiment can be provided when the at least one switch element can be transferred from the first position into the second position and/or from the second position into the first position by flexing or by deformation, preferably in a central region of the switch element. 
     According to an embodiment, the at least one switch element can adopt a third position in which the switch element unblocks a third flow rate, and the at least one switch element is configured to be moved from the first position into the third position upon a pressure reduction, preferably the third flow rate of the damping fluid being larger than the first flow rate. 
     In other words, at least three positions of the switch element can be realized hereby. In the first position, the switch element at least partially covers the channel of the piston so as to provide a first damping force. In the second position of the switch element, the overload case is present, in which a channel of the piston can be unblocked by the switch element so as to provide a rapid pressure reduction within the damper housing. In the third position, the channel of the piston is covered by the switch element only to a reduced extent so as to provide a second damping force which is smaller than the first damping force. 
     During normal operation of the furniture damper, the switch element will thus only be moved between the first position and the third position so as to provide two different damping forces. In the second position, on the contrary, the overload case is present in which the switch element unblocks a channel of the piston in order for the damping fluid to stream more rapid from the high-pressure side to the low-pressure side of the furniture damper. 
     According to an embodiment, the at least one switch element, in the third position, adopts a substantially flat neutral position, and adopts a flexing position in the second position. In the flexing position, the at least one switch element is at least partially deformed or flexed relative to the neutral position. 
     Preferably, the at least one switch element, in the first position, adopts a further flexing position in which the at least one switch element is at least partially deformed or flexed relative to the neutral position, and is deformed or flexed to a lesser extent relative to the flexing position of the second position. 
     With a preferred embodiment, the at least one switch element:
         is formed by a rubber material or by a plastic material, and/or   is configured rotationally symmetrical, and/or   is configured substantially cylindrical, and/or   is configured substantially as a lamella.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention will be explained with the aid of the following description of figures. 
         FIG.  1    is a perspective view of an item of furniture comprising a furniture carcass and furniture parts in the form of drawers movably-supported relative to the furniture carcass, 
         FIG.  2   a ,  2   b    show a furniture fitting in the form of a drawer pull-out guide in a perspective view and an enlarged detail view thereof, 
         FIG.  3   a - 3   e    show the furniture damper in an exploded view and in different positions with an extended and a retracted piston rod, 
         FIG.  4   a - 4   d    show the furniture damper with the different positions of the switch element, 
         FIG.  5   a ,  5   b    show the furniture damper in a perspective cross-sectional view and an enlarged detail view thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG.  1    shows an item of furniture  1  comprising a cupboard-shaped furniture carcass  2 , and movable furniture parts  3  in the form of drawers  3   a  are displaceably supported relative to the furniture carcass  2  via furniture fittings  4  in the form of drawer pull-out guides  4   a . Each of the drawers  3   a  includes a front panel  5 , a drawer bottom  6 , drawer sidewalls  7  and a rear wall  8 . 
     Each of the drawer pull-out guides  4   a  includes a carcass rail  9  configured to be fixed to the furniture carcass  2  via at least one fastening portion  12   a ,  12   b , and a drawer rail  10  displaceably supported relative to the carcass rail  9 , the drawer rail  10  being connected or being configured to be connected to the drawer sidewall  7 . Optionally, the pull-out guide  4   a  can further include a central rail  11  displaceably supported between the carcass rail  9  and the drawer rail  10  so as to provide a full-extension of the drawer  3   a.    
       FIG.  2   a    shows the furniture fitting  4  configured as the drawer pull-out guide  4   a  in a perspective view. The drawer pull-out guide  4   a  includes the carcass rail  9  configured to be fixed to the furniture carcass  2  via the fastening portion  12   a ,  12   b , the drawer rail  10  configured to be fixed to the drawer  3   a , and the central rail  11  is displaceable between the carcass rail  9  and the drawer rail  10 . 
     A, preferably pin-shaped, fastening element  13  is arranged on the rear end of the drawer rail  10 , the fastening element  13  engaging into a provided opening of the drawer  3   a  in a mounted condition of the drawer  3   a  on the drawer pull-out guide  4   a  so as to stabilize the rear region of the drawer  3   a  in a direction extending transversely to the longitudinal extension of the drawer rail  10 . A coupling device  14  is arranged on the front end of the drawer rail  10 , the coupling device  14  including a coupling portion  14   a  configured for manual actuation. By the coupling portion  14   a , the front region of the drawer  3   a  can be releasably coupled to the drawer rail  10 . 
       FIG.  2   b    shows the oval region according to  FIG.  2   a    in an enlarged view. For retracting the drawer rail  10  into a closed end position, an entrainment member  17  pressurized by a spring device  18  is provided. The entrainment member  17  is configured to be releasably coupled to a coupling element arranged on the carcass rail  9  so as to retract the drawer rail  10  into the closed end position by a force of the force storage member  18 . 
     For dampening the spring-assisted retraction movement of the drawer rail  10 , a furniture damper  15  with a damper housing  19  is provided. In the shown embodiment, the furniture damper  15  is fixed to the drawer rail  10  via a carrier  16 . 
       FIG.  3   a    shows the furniture damper  15  in an exploded view. The furniture damper  15  includes a, preferably cylindrical, damper housing  19  in which at least one fluid chamber  19   a  is arranged. A piston  20  with a piston rod  21  is linearly displaceably supported within the fluid chamber  19   a.    
     The piston  20  includes at least one channel  20   a , preferably a plurality of channels  20   a , for the passage of a, preferably hydraulic, damping fluid arranged in the fluid chamber  19   a.    
     Further, at least one switch element  22  is provided. The switch element  22 , when a damping stroke is performed and below a predetermined threshold value of a pressure application to the piston  20 , is configured to be moved into a first position in which the at least one channel  20   a  of the piston  20  is at least partially covered by the switch element  22  and a first flow rate of the damping fluid streams through the at least one channel  20   a  of the piston  20 . 
     The switch element  22  can include at least one hole  22   a , preferably precisely two holes  22   a , the at least one hole  22   a  being in a fluid-conductive connection or being configured to be brought into a fluid-conductive connection with the channel  20   a  of the piston  20 . 
     The piston  20  includes at least one bearing location  26 , and the at least one switch element  22  is movably supported on the bearing location  26 , preferably in an axial direction of the piston  20 . 
     The piston rod  21  can be immersed into the fluid chamber  19   a , whereby the volume of the fluid chamber  19   a  is variable. By a compensation device  23  configured to be deformed or moved so as to vary a change of the volume of the fluid chamber  19   a , the additional volume of the piston rod  21  can be compensated for upon an entry into the fluid chamber  19   a . The compensation device  23  can include a deformable material portion arranged in the fluid chamber  19   a  or a compensating element  23   c  displaceable within the fluid chamber  19   a . The compensating element  23   c  is movable against a force of the force storage member  23   a  upon performing the damping stroke. The force storage member  23   a  presses against the compensating element  23   c  via a supporting portion  23   b.    
     By a closure element  25 , the damper housing  19  can be closed, and the piston rod  21  is passed through the closure element  25 . 
       FIG.  3   b    shows the furniture damper  15  in a side view, in which the piston rod  21  is located in an extended position relative to the damper housing  19 .  FIG.  3   c    shows a cross-sectional view along the plane A-A according to  FIG.  3   b   . The piston  20  located within the fluid chamber  19   a  can be seen. 
       FIG.  3   d    shows the furniture damper  15  in a side view, in which the piston rod  21  and the piston  20  are located in a retracted end position relative to the damper housing  19 . 
       FIG.  3   e    shows a cross-sectional view along the plane A-A according to  FIG.  3   d   . The additional volume of the piston rod  21  received in the fluid chamber  19   a  can be compensated for by the compensation device  23 . It can be seen that the compensating element  23   c  of the compensation device  23 , in a direct comparison with  FIG.  3   c   , has slightly been moved to the left against a force of the force storage member  23   a  upon the entry of the piston rod  21 . In  FIG.  3   e   , the force storage member  23   a  is in a more compressed condition than in  FIG.  3   c   . However, such compensation devices  23  are well-known and need not to be further described in detail here. 
       FIG.  4   a - 4   d    show the furniture damper  15  with the different positions (A, B, C, D) of the switch element  22 . The damper housing  19  with the fluid chamber  19   a  arranged therein can be seen, the fluid chamber  19   a  having a high-pressure side (HP) and a low-pressure side (LP) separated from the high-pressure side (HP) by the piston  20 . Preferably, the switch element  22  is arranged on the high-pressure side (HP). The piston  20  includes at least one channel  20   a , preferably a plurality of channels  20   a , for the passage of a damping fluid arranged in the fluid chamber  19   a . The piston  20  is connected to the piston rod  21 , the piston rod  21  being led out from the damper housing  19 . 
       FIG.  4   a    shows the first position (A) of the switch element  22 , in which the channel  20   a  of the piston  20  is at least partially covered by the switch element  22  and in which a first flow rate of the damping fluid streams through the channel  20   a  of the piston  20 . Upon a movement of the piston  20  in a direction  29  of the damping stroke, the damping fluid streams from the high-pressure side (HP) through a gap  29  formed between the switch element  22  and/or the piston  20  and an inner wall  30  of the fluid chamber  19   a  to the low-pressure side (LP). Moreover, the damping fluid streams from the high-pressure side (HP) through the holes  22   a  of the switch element  22  and through the channels  20   a  of the piston  20  to the low-pressure side (LP). This is symbolized by the paths W1, W2. 
     In the first position (A), the switch element  22  adopts a flexing position in which the switch element  22  is at least partially deformed or flexed relative to a flat neutral position ( FIG.  4   c   ). 
       FIG.  4   b    shows the second position (B) of the switch element  22  and thus the overload case. Upon an excessive, jerky pressure application to the piston  20  in a direction  29  of the damping stroke, the switch element  22  can be transferred from the first position (A) into the second position (B) through flexing or through deformation, preferably in a central region. 
     The flexing or the deformation of the switch element  22  can be favorized by the central opening  22   b  of the switch element  22 , the central opening  22   b  having a stepped configuration in diameter in a cross-section. The diameter of the opening  22   b  can be enlarged by flexing or by a deformation of the switch element  22  so as to increase the flow rate of the damping fluid above the predetermined threshold value of pressure application to the piston  20 . In the second position (B) shown in  FIG.  4   b   , the switch element  22  adopts a further flexing position, the further flexing position being stronger deformed or stronger flexed relative to the flexing position of first position (A). 
     The piston  20  includes at least one, preferably non-symmetrical, abutment  27 , and the switch element  22  is configured to bear at least partially against the abutment  27  in the second position (B). The annular gap formed between an outer perimeter of the bearing location  20   b  and an inner perimeter of the central opening  22   b  can be significantly enlarged in a region of the path W3 so as to rapidly transport the damping fluid in the overload case via the paths W3, W2 to the low-pressure side (LP). In contrast, in the first position (A) of the switch element  22  (see  FIG.  4   a   ), the annular gap is closed in the region of the path W3. 
     The switch element  22  includes at least one hole  22   a , preferably precisely two holes  22   a . It can be preferably provided that the at least one hole  22   a  is peripherally arranged on the switch element  22  and/or can be closed or at least partially closed by bearing against a counter surface  31  of the piston  20 . 
       FIG.  4   c    shows a third position (C) of the switch element  22 , in which the switch element  22  unblocks a third flow rate. Upon a pressure reduction, the at least one switch element  22  can be moved from the first position (A) into the third position (C). Preferably, the third flow rate is larger than the first flow rate. The increased third flow rate is symbolized by the three paths W1, W2, W3. 
     The switch element  22  can be moved from the third position (C) into the first position (A) and/or from the first position (A) into the third position (C) by flexing or by deformation, preferably in a central region. In the third position (C), the switch element  22  adopts a flat neutral position. 
       FIG.  4   d    shows a further position (D) of the switch element  22 , in which the switch element  22  unblocks the at least one channel  20   a  of the piston  20 , preferably all channels  20   a  provided in the piston  20 , upon a movement of the at least one piston  20  in a direction opposite the damping stroke. This is the case when the piston rod  21 , upon a return stroke, is pulled out from the damper housing  19  in a direction opposite the direction  29  of the damping stroke. By unblocking the channels  20   a , a rapid return movement of the piston rod  21  with a low fluid resistance can be made possible. 
       FIG.  5   a    shows the furniture damper  15  with the already described components in a perspective cross-sectional view. 
       FIG.  5   b    shows the encircled region of  FIG.  5   a    in an enlarged view. The piston  20  displaceable within the fluid chamber  19   a  can be seen, and the high-pressure side (HP) and the low-pressure side (LP) are separated from one another by the piston  20 . The switch element  22  is displaceably supported on the bearing location  26  of the piston  20  in an axial direction of the piston  20 . Well to be seen is the stepped configuration of the central opening  22   b  and the channels  20   a  extending through the piston  20 . Instead of a stepped configuration, the central opening  22   b  may also have a conical or a cylindrical configuration in diameter. 
     The furniture damper  15  according to the invention has been shown in the drawings in combination with a furniture fitting  4  in the form of a drawer pull-out guide  4   a . However, it is immediately apparent that the furniture damper  15  can also be applied to other furniture fittings  4 . 
     The furniture fitting  4  can include at least two components configured to be moved relative to one another, and a relative movement of the at least two components can be dampened by the furniture damper  15 , and/or that the furniture fitting  4  is configured as a furniture drive for moving a movably-supported furniture part  3 , as a furniture hinge for moving a movably-supported furniture part  3 , or as a damping device for dampening a movement of a movable furniture part  3 .