Abstract:
A seat guide device has at least one linear guide system and a seat base supported in a movable fashion on the carriage of said system against the force of a spring. The device further comprises:
       (a) damping element coupled to at least one of the carriage and the spring, and   (b) a block and tackle which includes:       (1) one fixed end which is attached to a stationary attachment point;   (2) one loose end which is connected to the carriage; and   (3) one first loose pulley which is connected to a stationary attachment point via the spring.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a seat guide device with at least one linear guide system and with a seat base being supported in a movable fashion on the carriage of the system against the force of a spring. 
     Such seat guide devices are known in particular from the former Bundestag [German Parliament] building in Bonn and the Reichstag [Imperial Diet] building in Berlin. The seats are arranged on and use a support pipe as the seat base, which is supported in a longitudinally movable fashion on the carriage of the linear guide system. In this manner, it is possible to move the seat away from the table, and in so doing giving the spring a tension, which returns the seat base with the seat to its initial position once the user gets up. This automatic return of the seats provides a harmonious arrangement in larger halls and keeps the exit routes behind the seat rows free in that the seats are returned automatically to the initial position; i.e., being guided towards the tables or away from them depending on the installed position. 
     It has been demonstrated that at greater travel distances, the developed spring tension is so great that the seat with its base is accelerated significantly and hits hard at the stop. Both the mechanical stress and, in particular the associated noise, are undesirable. 
     SUMMARY OF THE INVENTION 
     It is, therefore, the objective of the invention to return the seat base of a seat guide device of the aforementioned kind to its initial position in a controlled manner, in particular with a reduced speed compared to the known seat of this type. 
     This objective, as well as further objectives which will become apparent from the discussion that follows, are achieved, in accordance with the present invention, by providing a damping element, coupled to the carriage and/or the spring, and a block and tackle having at least:
         one fixed end which is attached to a stationary attachment point;   one loose end which is connected to the carriage; and   one first loose pulley which is connected to a stationary attachment point via the spring.       

     Because the carriage and/or the spring are coupled with a damping element, the seat base, which is accelerated by the tension of the spring, is slowed down. By providing a block and tackle, the tensioning path of the spring is reduced at the same time such that, with the same spring constant as with seat guide device known in the art, the displacement of the spring when moving the seat base back, and thus the tensioning forces, can be reduced by half. 
     In particular, the arrangement of a block and tackle allows for the use of a gas pressure spring through which the spring and the damping element can be combined. Because of the block and tackle, a gas pressure spring with a short design can be employed. This allows for retrofitting of known seat guide devices without the need to change the overall length of the device. Rather, it is possible to integrate the gas pressure spring in the free space between the preferably two parallel linear guides arranged at a prescribed distance to one another underneath the travel of the carriage. 
     A second block and tackle that operates opposite to the first block and tackle is provided in a preferred embodiment. 
     This preferred embodiment designed such that, at the second block and tackle, a fixed end is attached to a stationary attachment point, which with regard to the linear guide system is on the opposite side of the stationary attachment point of the first block and tackle, wherein a loose end is connected with the carriage and wherein a second loose pulley of the second block and tackle coincides with the first loose pulley or is arranged with it on the same rotational axis, or exhibits a rotational axis that is positively connected with the rotational axis of the first loose pulley. 
     This arrangement in particular avoids the problem of slacking cables when the tensioned spring expands and accelerates the carriage together with the seat base and the seat. The second counter-acting block and tackle has the effect that the seat base can move only according to the movement of the first block and tackle, but that the seat base cannot run ahead of the movement of the first block and tackle, or the return pulley of the first block and tackle, respectively. This prevents the cable from coming off the preferably profiled return pulley. The loose pulleys of the first end of the second block and tackle are coupled such that the movement in the first block and tackle leads to a simultaneous counter-movement of equal length in the second block and tackle. The second block and tackle gives way in the amount that the carriage is pulled back to its initial position. Thus, the carriage is positively suspended between the two loose ends of the two block and tackles and can move only proportional to the displacement of the gas pressure spring. 
     Preferably both block and tackles use a common loose pulley, which is approached from opposite directions. There may also be two separate pulleys provided, which are supported by a common rotational axis. These embodiments save the most design space. 
     If more design space is available, the loose pulleys of both block and tackles may also be coupled in some other manner, such that the distance of their rotational axes remains unchanged. 
     Since a seat guide device is typically long and narrow, due to the linear travel, it is advantageous to attach the fixed ends of both block and tackles at opposite sides of the travel and then to provide several return pulleys in order to create the different force attack directions of the two block and tackles. 
     To affect a space-saving design, it may be provided to attach the loose pulley of the first block and tackle and possibly also of the second block and tackle directly at the tip of the piston rod of the gas spring. 
     To achieve simple assembly and/or maintenance, it is advantageous to arrange the return pulleys in pulley carrier units, each exhibiting a horizontal axis that stretches perpendicular to the travel. Also provided in the housing are grooves or other recesses perpendicular to the direction of travel, which stretch, when viewed in a cross-section from the side, in a slanted manner down from one top side of the housing and at the same time to the center of the housing. Thus, the pulley carrier units can be installed by simply sliding their horizontal axes into the recesses. The slant in the recesses prevents the pulley carrier units from sliding out on top of the recesses. In this manner, no additional means of attachment are required for the pulley carrier units. The cable paths determine the distance between the horizontal axes of the pulley carrier units through the slant towards the inside and the coupling of the two block and tackles via a common loose pulley and via attachment points at the carriage. Only after loosening one of the loose ends of the block and tackles can the pulley carrier units be pulled apart from each other and thus pulled out of the recesses in the housing. 
     One preferred embodiment also provides for the gas pressure spring to be coupled directly to one of the pulley carrier units. 
     For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of the seat guide device according to the present invention. 
         FIG. 2  is a sectional side view of the seat guide device of  FIG. 1 . 
         FIG. 3   a  is a schematic presentation, viewed from above, of a first embodiment of the cable path in the seat guide device of  FIG. 1 . 
         FIG. 3   b  is a schematic presentation, viewed from above, of a second embodiment of the cable path in the seat guide device of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention will now be described with reference to  FIGS. 1-3   b  of the drawings. Identical elements in the various figures are designated with the same reference numerals. 
       FIG. 1  shows a seat guide device according to the present invention where all parts are integrated in one housing  1 . Two linear guides  3  are located parallel and at a certain distance to one another in a housing  1 . The seat base  21  is mounted to the rectangular plate  20 , which forms a common carriage for the two linear guides  3 . 
     Pulley carrier units  10 ,  36  are located to the left and right of the linear guides  3 . They each exhibit a horizontal lateral axis  17 ,  37 , which is suspended in corresponding grooves  4 ,  5  in the housing  1 . 
     The right pulley carrier unit  36  exhibits at its lateral axis  37  an attachment point  35  from which a first cable  50  with its fixed end  51  runs to the return pulley  53  and from there leads as a loose end  52  to an attachment point  22  at the carriage  20 . 
     The left pulley carrier unit  10  incorporates two return pulleys  11 ,  12  as well as an attachment point  13 , where the cable of a second block and tackle is attached. From the attachment point  13  runs the cable  64  to a loose return pulley  53  and continues from there as cable  63  around the return pulleys  11 ,  12  and then from the left housing side into the interim space between the linear guides  3  to the return pulley  33 , which is supported in a rotating manner at the second pulley carrier unit  36 . From the pulley  33 , the cable then runs with its loose end  61  to the carriage  20 , where it is clamped to the attachment point  22 . 
     Through the cable  61 ,  62 ,  63 ,  64 , the carriage  20  is held back by a return piston movement from left to right triggered by the gas pressure spring  30  according to the embodiment in  FIG. 1 . 
     Return pulleys  2 , with a belt running around them, are provided on the face side in the housing. This belt covers the recess in a not shown cover of the housing  1 , with the seat base  21  being supported in a movable manner in the recess. 
       FIG. 2  shows the seat guide device with the same position of the carriage and the seat base  21  in a sectional side view. 
     In particular, the slanted profile of the recesses  4 ,  5  for the horizontal lateral axis  17 ,  37  of the pulley carrier units  10 ,  36  can be recognized in this drawing. Additionally recognizable is that all cables and pulleys are arranged in one plane, resulting in a particularly flat construction. 
       FIG. 3   a  again schematically shows the cables of the design described previously based on  FIGS. 1 and 2  with the two block and tackles. Dashed lines on the left and right indicate the pulley carrier units  10 ,  36 . The carriage  20  is shown in the center. 
     The first block and tackle is formed by a first cable  50  with its fixed end  51  being attached to the attachment point  35  at the pulley carrier unit  36  and running across the loose pulley  53 , and with its free end  52  then returning to the attachment point  22  at the carriage. 
     If the carriage  20  is moved from left to right, then by the pull at the free end  52 , the pulley  53  is pulled to the right causing the piston rod  31  to be pushed into the gas pressure spring cylinder  32  as well. This causes tensioning of the gas pressure spring  30 . During the movement of the carriage from left to right under the tension of the gas spring  30 , a simultaneous pull is exercised on the second cable via the loose pulley  53 . During the pull movement via the cable section  63 , the return pulleys  12  and  11 , the cable section  62  and the return pulleys  33 , the loose end  61 , which is also attached to the carriage  20 , is pulled, i.e., the second cable is being tensioned. 
     If the gas pressure spring  30  is now given the opportunity to expand, for example, because the user stands up from the seat, the piston rod  31  pushes into the cable  51 ,  52  via the pulley  53  and pulls the carriage  20  to the left. To prevent the carriage  20  from running ahead of the cable movement at great acceleration, and to prevent the first cable  50  from coming off the return pulley  53 , the carriage  20  is connected to the second cable; i.e., the carriage  20  is held back via the sections  61 ,  62 ,  63  of the second cable with the return pulleys  33 ,  11 ,  12 ,  53 . 
     By the fact that both cables use the same loose pulley  53 , or at least have pulleys with rotational axes that are in a fixed position to one another, only as much cable can be released on the second cable, which is functioning as the holding cable, as on the first cable due to the return pulley  53  moved by the gas pressure spring cylinder. This presupposes an essentially equal angle of contact at the loose pulley  53 . Thus, the different diameters at this pulley shown in  FIG. 3   a  serve only the purpose of better presentation and do not constitute a preferred embodiment, because a slip would occur due to different arc lengths of the cables in the contact area of the pulley  53 . 
       FIG. 3   b  shows, in a schematic functional form, the cable guides of a slightly modified embodiment, where only one return pulley  11  is provided in the left pulley carrier unit  10 . For all other individual components, as well as in its function, the embodiment shown in  FIG. 3   b  corresponds to the embodiment shown in  FIG. 3   a . By doing without an additional return pulley in the left pulley carrier unit  10 , the design and apparatus investments for the device according to the invention are reduced. 
     There has thus been shown and described a novel seat guide device which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.