BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a mechanism for changing a length or position of a support surface of seats and/or couches.  
           [0003]    2. Description of the Prior Art  
           [0004]    Modern, mass-produced upholstery furniture pieces such as seats and/or couches have backrests with a constant height. Therefore, they do not provide an appropriate support for short persons. For tall persons, the height of the seat backrests often is too short. The leg support for tall persons is also inadequate, and a tall person cannot properly bend his/her legs because a short distance between the seat and a floor surface.  
           [0005]    Accordingly, an object of the present invention is a mechanism for changing the position of the support surface(s), e.g., of the seating surface, in such a way that the position of at least one of associated support surfaces, which are smoothly combined with each other, can be easily arbitrary changed.  
         SUMMARY OF THE INVENTION  
         [0006]    This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a mechanism for changing a position of a support surface for seats and couches and a length of which changes in a longitudinal direction, and including two horizontally spaced from each other, telescopic rods having each a bent region, two slide connection elements surrounding the two telescopic rods and carrying a deformable region of the support surface, and two telescopic sleeves in which the two telescopic rods are telescopically displaceable. The mechanism permits to arbitrary change the position of a respective support surface, which permits to accommodate it for a person with a different height.  
           [0007]    The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The drawings show:  
         [0009]    [0009]FIG. 1 a perspective view of a support surface in a retracted condition;  
         [0010]    [0010]FIG. 2 a perspective view of a support surface in a pull-out condition;  
         [0011]    [0011]FIG. 3 a perspective view of a support frame for the support surface;  
         [0012]    [0012]FIG. 4 a perspective view of the support frame shown in FIG. 3 for relaxation of thigh muscles;  
         [0013]    [0013]FIG. 5 a cross-sectional view of telescopic rods and the support surface;  
         [0014]    [0014]FIG. 6 a side view of a folding mechanism;  
         [0015]    [0015]FIG. 7 a side view of the folding mechanism shown in FIG. 6 in its extended position;  
         [0016]    [0016]FIG. 8 a schematic view of the telescopic arrangement in its retracted position;  
         [0017]    [0017]FIG. 9 a schematic view of the telescopic arrangement in its pull-out position;  
         [0018]    [0018]FIG. 10 a schematic view of a bending zone of another embodiment of the displacement mechanism;  
         [0019]    [0019]FIG. 11 a perspective view of a deformable region of the support surface;  
         [0020]    [0020]FIG. 12 a perspective view of a telescopic leg with a portion of the retracted support surface;  
         [0021]    [0021]FIG. 13 a perspective view of a telescopic leg with a portion of the pull-out support surface;  
         [0022]    [0022]FIG. 14 a view showing the telescopic leg shown in FIG. 12 with a covering; and  
         [0023]    [0023]FIG. 15 a view showing the telescopic leg shown in FIG. 13 with a covering.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    [0024]FIG. 1 shows a deformable region  22  of the support surface  3  in the retracted position of the support surface  3 . In the position shown in FIG. 1, telescopic rods  1  of the telescopic mechanism are completely inserted in telescopic sleeves  2  provided in the frame of the telescopic mechanism. The support surface  3  is displaced into its retracted position to accommodate a short person. The displacement of the telescopic rods  1 , together with the support surface  3  secured thereto, is effected by a height controlling mechanism including tooth bars  4  which are attached to the support surface  3 , and tooth gears  5  which cooperate with respective bars  4  and which are supported on a common shaft supported in brackets  7  secured to respective sleeves  2 . The displacement of the support surface  3  is effected manually with a hand wheel  6 . The support surface  3  can be displaced in any position between the completely retracted position shown in FIG. 1, and a completely pull-out position shown in FIG. 2 in which the deformable region is completely expanded as shown with a reference numeral  23 .  
         [0025]    [0025]FIG. 3 shows the support frame  30  for the support surface  3 , together with the height controlling mechanism.  
         [0026]    [0026]FIG. 4 shows the support frame  30  shown in FIG. 3 but with means for relaxation of thigh muscles. The relaxation means includes a support  12  and a resilient strip  14  mounted on the support  12  and having a smooth surface  13 .  
         [0027]    [0027]FIG. 5 shows a cross-sectional view of the telescopic rods  1  and the support surface  3  which is attached to slide connection elements  8  surrounding the telescopic rods  1  and secured thereto. Means  9  provides for stretching of the support surface  3 . The reference numeral  9  represent a back cover which can be more elastic or less elastic. The support surface  3  can be formed of upholstery  10  of textile or foam material which is covered by a covering  11 .  
         [0028]    [0028]FIG. 6 shows a folding mechanism  15  which controls the position of the telescopic sleeve  2 . The telescopic sleeve  2  is retained in its predetermined position by an axle bolt  17  displaceable in a slot  16 .  
         [0029]    [0029]FIG. 7 shows the position of the folding mechanism  15  in a maximum extended position of the sleeve  2 .  
         [0030]    [0030]FIGS. 8 and 9 show the mechanism for displacing the telescopic rods  1  between their retracted (FIG. 8) and pull-out (FIG. 9) positions which correspond, respectively, to folded and extended positions of the telescopic sleeves  2  which are determined by positions of the axle bolt  17  in the slot  16 . The axle bolt  17  is displaced by displacement bars  18  which is displaced by a lever mechanism including two levers  19 . The free ends of the levers  19  are connected with the telescopic rods  1  by displacement bars  20 . Upon appropriate actuation of the lever mechanism, the telescopic sleeves  2  and the telescopic rods II are displaced from the retracted position shown in FIG. 8 to the pull-out position shown in FIG. 9.  
         [0031]    [0031]FIG. 10 shows an end element  21  with which a synchronized displacement of the telescopic rods  1  is achieved. The end element  21  is attached to a region  25  of the support surface  3  the length of which does not change during displacement of telescopic rods  1  between the retraced and pullout positions. With the constant length region  25 , a height-controlling mechanism for displacing the telescopic rods  1  is not necessary. The retraction and pull-out is effected by a corresponding displacement of the cover  9  in a respective direction for displacing the telescopic rods  1  in the channels  26 .  
         [0032]    The end element  21  is connected to the bending region  25  in a predetermined spaced relationship with respect to the corresponding telescopic sleeves  2 . The angular position of the deformable end element  21  influences the position of the telescopic rods  1 . The different positions of the telescopic rods  1  correspond to different degrees of deformation of the end element  21  which is supported at its opposite ends in brackets  29  (FIG. 11). The position of the telescopic rods  1  depend on the degree of stiffness of the deformed end element  21 . Thus, the changing of the angular position or the degree of deformation of the end element  21  results in a desired displacement of the telescopic rods  1 . This permits to eliminate the height controlling mechanism. Different degrees of deformation of the end element  21  are shown in FIGS.  12 - 15 . The reference numeral  27  and  28  show the positions of telescopic rods  1  in the retracted (FIG. 12) and pull-out (FIG. 13) positions. Reference numerals  27   a ,  28   a  designate conditions of the coverings of the telescopic rods  1 .  
         [0033]    The present invention makes a substantial contribution to the advancement of health care. The present invention is based on an effective use of ecological resources. The present invention is based on a mechanical principle that contributes to economy of material and sets forth alternative possibilities of changing the conditions of the support surface without the use of external energy sources.  
         [0034]    Though the present invention was shown and described with references to the preferred embodiments, such are merely illustrative of the present invention and are not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.
A mechanism for changing a position of a support surface ( 3) for seats and couches and a length of which changes in a longitudinal direction, includes two horizontally spaced, telescopic rods ( 1) having each a bent region and displaceable in two telescopic sleeves ( 2), and two slide connection elements carrying a deformable region ( 22) of the support surface ( 3) and surrounding respective telescopic rods ( 1).