Abstract:
A seat bench transport device for transporting a bench of seats for a vehicle, comprising a chassis, a retaining rail pair that is arranged on the chassis and including two retaining rails extending parallel to one another for accommodating seat bench feet. The lengthwise sides of these rails that face one another are open at least in sections and the lengthwise sides thereof that face away from one another each have at least one locking section. A displacement mechanism moves the retaining rails transversely relative to one another.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of the U.S. Provisional Application No. 61/533,809, filed on Sep. 13, 2011, and of the German patent application No. 10 2011 082 602.5 filed on Sep. 13, 2011, the entire disclosures of which are incorporated herein by way of reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a seat bench transport device for transporting a seat bench for a transport vehicle. 
     Seat benches for use as seating in aircraft are usually transported to the aircraft on a mobile outside device, then loaded onto a mobile inside device and moved with this inside the aircraft fuselage to their respective installation positions. A conventional outside device for transporting a seat bench to the aircraft is shown in  FIG. 1 . This outside device  1  for transporting a seat bench  2  comprises a pallet  8  that is movable on caster pairs  4 ,  6 , and on which a plurality of seat rail pairs is mounted securely in the transverse position. Each seat rail pair includes two seat rails  10   a ,  10   b , arranged parallel to one another, which correspond to a distance between the rails in the aircraft. In this way, a large number of different seat benches  2  can be transported with the outside device  1 . The seat bench  2  shown comprises three seats  12 ,  14 ,  16  with a shared seat support beam  18 , whose seat bench feet for example can only be accommodated in one of the seat rail pairs  10   a ,  10   b.    
     For transporting seat bench  2 , seat bench feet  20 ,  22  are inserted into seat rails  10   a ,  10   b  transversely relative to pallet  8  and then secured in place via a locking mechanism, which is not shown. In order to transfer seat bench  2  from the outside device to the inside device inside the aircraft, the locking mechanism is released and seat bench  2  is slid out of seat rails  10   a ,  10   b  transversely relative to pallet  8 . 
     However, inserting the seat benches in the seat rails is very time-consuming. In addition, the locking mechanism regularly catches when it is opened, causing further delays. Moreover, the seat rails, seat bench feet and the locking mechanism can be damaged as a result of this catching. It is also disadvantageous that seat benches with asymmetrical seat support beams cause the device&#39;s center of gravity to shift, making the outside device more difficult to move. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to produce a seat bench transport device that eliminates the disadvantages described in the preceding and enables transportation of seat benches having differently spaced seat bench feet. 
     This object is solved with a seat bench transport device having the features of claim  1 . 
     A seat bench transport device according to the invention for transporting a seat bench for a vehicle includes a chassis, a retaining rail pair disposed on the chassis, including two retaining rails that extend parallel to one another to accommodate seat bench feet, the lengthwise sides of these rails that face one another being open at least in sections and the lengthwise sides thereof that face away from one another each having at least one locking section, and a displacement mechanism for moving the retaining rails transversely relative to one another. 
     Because the retaining rails are movable transversely relative to one another, individual distances between seat bench rails may be simulated, so that seat benches of any kind may be transported. The seat bench transport device according to the invention thus constitutes a universal transport tool for all seat benches. Since the retaining rails are open at least in sections along the lengthwise side facing the other rail, the seat benches may be deposited on the chassis without difficulty. The laborious, time-consuming activity of sliding the seat benches in the lengthwise or crosswise direction of the seat bench transport device is no longer necessary. Since each of the retaining rails has at least one locking section on the longitudinal side thereof facing away from the other rail, the seat benches are automatically secured in place when the retaining rails on the seat bench transport device are moved together, and automatically released when the retaining rails are moved apart. This also saves installation time. Moreover, the arrangement prevents the retaining rails from being damaged and/or the seat benches from becoming caught in the retaining rails. The seat bench transport device is also ideally suitable for use inside the vehicle, so that time-consuming reloading of the seat benches onto a second transport device is not necessary and this also reduces installation time. 
     The retaining rails are preferably movable simultaneously. This enables maximum movement of the retaining rails relative to one another in a single operation, so that the seat benches may be rapidly secured and rapidly released again. Alternatively, however, the retaining rails may also be separately adjustable. 
     In a preferred embodiment, the displacement mechanism is equipped with two threaded rods aligned in the direction of displacement, each of which is allocated to a retaining rail, and a gearwheel that is disposed between the threaded rods and meshes with them, and an actuating element for driving the gearwheel. This embodiment is technically simple to construct and extremely sturdy, which is to say not prone to malfunction. 
     In another embodiment, the displacement mechanism is equipped with a link disk, guide bolts on the retaining rail side for transmitting a rotating motion of the link disk to the retaining rails, and an actuating element for driving the link disk. This embodiment is also technically simple to construction and very sturdy. 
     In order to enable the opening and closing movement of the retaining rails to be effected evenly when the actuating element is operated, the spiral slots converge radially from the outside towards the inside. A pinion that is connected to the gearwheel or the link disk is advantageously supported on an axis of rotation of the gearwheel and is also in operative connection with the actuating element. The pinion is easy to mount on the axis of rotation of the gearwheel. In addition, the link disk may particularly have any outer contour, so that it is adaptable to the spiral slots in instances where unoccupied disk sections may be removed from the spiral slots. A preferred link disk is for example oval in shape. 
     The actuating element may be a lever with a handle, which is attached to a segment of the gearwheel of the displacement mechanism to transmit a rotary movement of the lever to the pinion. The transmission enables maximum relative movement of the retaining rails towards one another for minimum rotary movement, thus enabling both the disposal of the seat benches on the seat bench transport device and the release thereof to be accomplished more quickly. 
     The displacement mechanism preferably has a positioning disk, in which a plurality of arc slots is provided for guiding the handle, each of which has an arc length that corresponds to a travel distance between an open position and a closed position of the retaining rails for each seat bench rail distance. This enables the lever to be moved between a defined open or releasing position and a defined closed or locking position, which makes removal and locking of the respective seat bench considerably easier. 
     Removal of the respective seat bench may be rendered simpler still if the retaining rails are spring-biased in the opening direction, so that they are able to move apart automatically. 
     The arc slots may be radially offset from each other, while at the same time adjacent arc slots adjoin each other radially, and the handle is shiftable in the lengthwise direction of the lever. Limit stops for the lever movements are defined by the relative radial offset, which correspond uniquely to the locking positions and release positions. The radial interconnections between adjacent arc slots mean that adjustments for changing rail distances may be made quickly. 
     In order to prevent inadvertent opening of the retaining rails, the lever may be secured in the respective locking position for the retaining rails. 
     Securing may be assured for example by creating at least one securing drillhole in each arc slot to accommodate a securing pin of the handle. 
     Alternatively, each of the arc slots may be constructed with a shoulder. This variant enables reliable locking with a smaller number of components, since a mechanism for inserting and removing a securing pin may be dispensed with. In this variant, for example a crossbar, a threaded bolt or similar may be used as the handle. 
     In order to be able to set the optimal position of the center of gravity of the seat bench transport device even for seat benches with asymmetrical support beams, casters on the chassis may be adjustable relative to each other in the direction of travel of the retaining rails. 
     In a technically simple variant, the casters are disposed on telescopic arms, which are displaceable along a base frame of the chassis. 
     In order to enable multiple seat bench transport devices to be stacked on top of each other, it is advantageous if the seat bench transport device is furnished with caster recesses to accommodate the casters of a seat bench transport device stacked on top of it. A stacking capability particularly saves space when the devices are stored and enables a number of seat bench transport devices to be moved conveniently when they are not in use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantageous embodiments of the invention are the object of the additional dependent claims. 
       In the following, preferred embodiments of the invention will be explained in greater detail with reference to diagrammatic representations. These show: 
         FIG. 1  a seat bench transport device according to the prior art, 
         FIGS. 2 ,  3  and  4  a first embodiment of a seat bench transport device of the invention, 
         FIG. 5  a detail from the first embodiment, 
         FIG. 6  a plurality of stacked seat bench transport devices of the invention, 
         FIGS. 7 ,  8 ,  9  and  10  an operating mechanism of the seat bench transport device with reference to the first embodiment, 
         FIGS. 11 ,  12  and  13  the first embodiment with caster pairs displaced relative to each other, 
         FIGS. 14 and 15  a second embodiment of the seat bench transport device of the invention, 
         FIG. 16  a detail from the second embodiment, 
         FIGS. 17 and 18  a third embodiment of the seat bench transport device of the invention, 
         FIG. 19  a detail from the third embodiment, 
         FIG. 20  a detail from a fourth embodiment of the seat bench transport device of the invention, and 
         FIGS. 21 and 22  a fifth embodiment of the seat bench transport device of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The same structural elements bear the same reference numbers, although for the sake of clarity not all of the elements are identified with their reference number in some of the figures. 
     In the plan views of  FIGS. 2 and 3 , in the side view of  FIG. 4 , and in the detail view of  FIG. 5 , a first embodiment of a seat bench transport device  24  is shown. This comprises a chassis  26 , two retaining rails  28   a ,  28   b  and a displacement device  30  for moving retaining rails  28   a ,  28   b  in opposite directions. 
     Chassis  26  comprises a base frame, which is formed by two side members  32 ,  34  and two cross members  36 ,  38  which connect side members  32 ,  34  to one another at the extremities thereof. Side members  32 ,  34  define a longitudinal direction x of seat bench transport device  1  and cross members  36 ,  38  define a transverse direction y of seat bench transport device  1 . 
     In order to move chassis  26 , as shown in  FIG. 4  seat bench transport device  1  is equipped with two caster pairs  40 ,  42 , which when view in transverse direction y comprise two casters arranged one beside the other. 
     In order to stack multiple seat bench transport devices  24 ,  24 ′ on top of each other in vertical direction z, seat bench transport device  24  has four cup-shaped caster recesses  44  to accommodate one caster each of caster pairs  40 ′,  42 ′ on the upper bench transport device  24 ′ ( FIG. 6 ). 
     As indicated by the numbered elements in  FIG. 2 , retaining rails  28   a ,  28   b  extend in transverse direction y. They are guided at their extremities in lengthwise direction x on side members  32 ,  34  and are displaceable in longitudinal direction x of seat bench transport device  24  from a position of small separation ( FIG. 2 ) to a position of large separation ( FIG. 3 ) relative to one another and back. Retaining rails  28   a ,  28   b  are preferably spring-biased in the opening direction. The longitudinal side of each that faces the other is of open design and the longitudinal side of each that faces away from the other is closed. In particular, as is shown in  FIG. 4 , each has a hook-like profile with a sliding portion  46  that is movable along side member  32 ,  34  and a locking portion  48  that extends at an angle and away from side members  32 ,  34 . Locking portions  48  serve to hook around a portion of the seat bench feet  20 ,  22  ( FIG. 4 ) to secure the seat benches (shown schematically at  2  in  FIG. 4 ) in lengthwise direction x on seat bench transport device  24 . In order to secure the seat benches  2  in transverse direction y, opposite sections of retaining rails  28   a ,  28   b  each have two for example weblike limiters  50 ,  52  at a distance from one another in transverse direction y, as indicated by the numbered elements in  FIG. 2 , and these limiters define a seating space  54  for inserting a seat bench foot  20 ,  22 . 
     As indicated by the numbered elements in  FIG. 3 , displacement mechanism  30  has a cross member  56 , a gear assembly and a positioning system. 
     Cross member  56  extends in transverse direction y and the end sections thereof are connected to the middle of side members  32 ,  34  as illustrated in  FIG. 3 . This cross member serves particularly to support the gear assembly. As is shown in  FIG. 5 , it has an axis of rotation drillhole  58  designed to define an axis of rotation for a gearwheel  60  and a pinion  62  of the gear assembly, and a pivot axis drillhole  64  designed to define a pivot axis for a toothed segment  66  of the gear assembly. Gearwheel  60 , pinion  62  and toothed segment  66  are not shown in  FIG. 5 . The one end portion of cross member  56  is flared out into a positioning disk  68  to form the positioning system. In particular, pivot axis drillhole  64  is located in the root are of the flaring. As is shown in  FIG. 3 , the position of rotation axis drillhole  58  in cross member  56  is such that the axis of rotation and thus also gearwheel  60  and pinion  62  are positioned equidistantly between side members  32 ,  34 . The axis of rotation is preferably located such that a center of gravity of the device lies on the axis of rotation when seat bench transport device  24  is in a home position. 
     As is indicated by the numbered elements in  FIGS. 3 and 4 , the gear assembly comprises two threaded rods  70 ,  72 , gearwheel  60 , pinion  62 , toothed segment  66 , two and one actuating element  74 . 
     Threaded rods  70 ,  72  are positioned at a distance from and parallel to one another and extend in lengthwise direction x. Each has a threaded portion and a rod portion, via which each is connected to a retaining rail  28   a ,  28   b.    
     Gearwheel  60  is supported such that it rotates about the axis of rotation that extends in vertical direction z through axis of rotation drillhole  58 . It is disposed between threaded rods  70 ,  72  and meshes with both rods, so that when it rotates threaded rods  70 ,  72  are moved in opposite directions in lengthwise direction x. A helical spring, not shown, is anchored on the axis of rotation to bias retaining rails  28   a ,  28   b  towards the open position, and one end section of this spring acts on gearwheel  60  while the other end section acts on cross member  56 . 
     Pinion  62  is supported on the axis of rotation of gearwheel  60  and meshes with toothed segment  66 . It is permanently connected to gearwheel  60 , so that a rotary motion of pinion  62  is transmitted to gearwheel  60 . 
     Toothed segment  66  is pivotable about the pivot axis that extends in vertical direction z. It is pivoted via actuating element  74 , which is permanently disposed on an axle pin  76  of toothed segment  66  for this purpose ( FIG. 4 ). 
     Actuating element  74  has a lever  78  that extends orthogonally to the pivot axis and a handle  80  that extends in vertical direction z. When lever  78  or handle  80  is moved clockwise, as represented in  FIGS. 2 and 3 , retaining rails  28   a ,  28   b  are moved toward one another. When lever  78  is moved counterclockwise, retaining rails  28   a ,  28   b  are moved apart. Handle  80  is movable within an elongated slot  82  extending in the longitudinal direction thereof such that it is radially displaceable when lever  78  is pivoted. At its foot it is equipped with a securing pin  84  that is displaceable in vertical direction z, and at its head it has a pushbutton  86  for withdrawing and inserting securing pin  84  ( FIGS. 8 and 10 ). 
     The positioning system essentially comprises positioning disk  68 , which constitutes a disk segment and in which a plurality of arc slots  88   a ,  88   b ,  88   c ,  88   d  is formed, as indicated by the numbered references in  FIG. 5 , for guiding handle  80  or a knob. 
     Arc slots  88   a  to  88   d  are offset relative to each other radially in respect of the pivot axis. In this context, they are offset relative to each other in such manner that when the distance between retaining rails  28   a ,  28   b  is smallest handle  80  engages in radially innermost arc slot  88   a  and when the distance between retaining rails  28   a ,  28   b  is greatest it engages in radially outermost arc slot  88   d  ( FIGS. 2 and 3 ). 
     Arc slots  88   a  to  88   d  are positioned relative to each other in the pivot direction in such manner that each of the arc slots  88   a  to  88   d  corresponds to a seat rail distance. For example, in the illustrated first embodiment four arc slots  88   a  to  88   d  are provided and accordingly four seat bench distances may be represented. Each arc slot is connected at its radial limits with the respectively adjacent arc slots  88   a  to  88   d , so that a staggered arc slot guide is formed. In particular, a laterally open overlap is formed between adjacent arc slots  88   a  to  88   d , so that handle  80  is able to be moved from one of the arc slots  88   a  to  88   d  to the next arc slot  88   a  to  88   d  with a radial movement. Arc slots  88   a  to  88   d  have an arc length that corresponds to a travel distance of retaining rails  28   a ,  28   b  for each seat rail distance. Each is furnished with two limit stops  90 ,  92  for handle  80  at the opposite extremities thereof, limit stops  90  defining an opening or releasing position and the other limit stops  92  defining a closing or locking position of retaining rails  28   a ,  28   b . In order to secure lever  78  in the respective locking position, a securing drillhole  94  is provided in the area of limit stops  92  at the locking extremity of each arc slot for the insertion of a securing pin  84 . 
     In the following, an operating mechanism according to the invention for seat bench transport device  1  as illustrated in  FIGS. 7 ,  8 ,  9  and  10  will be explained: 
     Starting from the separation between retaining rails  28   a ,  28   b  in  FIG. 7 , a seat bench is to be secured in position on seat bench transport device  24 . The preselected separation between retaining rails  28   a ,  28   b  is set according to the seat bench that is to be locked by appropriate positioning of handle  80 , in the example of the figure in third arc slot  88   c . As is shown in  FIG. 8 , securing pin  84  of handle  80  is retracted from securing drillhole  94 , and retaining rails  28   a ,  28   b  are forced apart, in the opening direction, under the spring bias of the helical spring. As shown in  FIG. 9 , lever  78  is turned counterclockwise and handle  80  is moved to the left until it comes to rest against release end limit stop  90 . Now the seat bench is placed on retaining rails  28   a ,  28   b . To lock the seat bench, lever  78  is turned clockwise via handle  80 , as shown in  FIG. 9 , until it comes to rest against locking end limit stop  92  and retaining rails  28   a ,  28   b  are moved to their locking positions. Then, as shown in  FIG. 10 , securing pin  84  is inserted into securing drillhole  94  by actuating pushbutton  86  to secure the locking position. Retaining rails  28   a ,  28   b  are now fixed in place and the seat bench is secured in lengthwise direction x and transverse direction y on seat bench transport device  24 . 
     In order to dismount the seat bench, pushbutton  86  of handle  80  is pressed, and securing pin  84  is withdrawn from securing drillhole  94 . Retaining rails  28   a ,  28   b  are then automatically moved apart into the open position as a result of the helical spring force, and handle  80  is moved counterclockwise as far as release end limit stop  90  ( FIG. 8 ). 
     In order to enable a compensated position of the center of gravity of seat bench transport device  24  in the case of asymmetrical seat support beams, caster pairs  40 ,  42  are movable in lengthwise direction x relative to each other, as shown in  FIGS. 11 ,  12  and  13 . Caster pairs  40 ,  42  are each supported on two telescopic arms  96 ,  98 , which are connected with one another via one transverse arm  100  for each. Telescopic arms  96 ,  98  extend through openings in the frontal faces of side members  32 ,  34 , and are displaceable in lengthwise direction x inside these members. In order to secure telescopic arms  96 ,  98  in a desired lengthwise position, for example cross pins are provided, not shown in the figures, and are inserted in aligned pin holes in side members  32 ,  34  and telescopic arms  96 ,  98 . As is shown in  FIGS. 11 and 12 , caster pairs  40 ,  42  may be moved regardless of the position of retaining rails  28   a ,  28   b . Accordingly, there is no operative connection between displacement mechanism  30  for retaining rails  28   a ,  28   b  and telescopic arms  96 ,  98 . As is shown in  FIG. 13 , caster pairs  40 ,  42  may also be moved individually, and for example the caster pair  42  on the right in  FIG. 13  may be extended on its own. 
     A second embodiment of the seat bench transport device  24  of the invention is depicted in the plan views of  FIGS. 14 and 15  and the detail view of  FIG. 16 . Unlike the first embodiment illustrated in  FIGS. 2 to 13 , particularly  FIGS. 2 to 5 , the second embodiment is furnished with five arc slots  88   a  to  88   e , so that five different seat bench distances may be reflected. Moreover, arc slots  88   a  to  88   e  are set apart from each other radially and thus also laterally, and they are joined to each other via a connecting radial slot  102 . Arc slots  88   a  to  88   e  are each prolonged beyond connecting radial slot  102 , thus creating blind limit stops  90 ,  92 . In this way, in contrast to the first embodiment, handle  80  cannot be shifted from the opening position and the locking position in an arc slot  88   a  to  88   e  into an adjacent arc slot  88   a  to  88   e  with a radial motion, instead the handle  80  must be freed from blind limit stops  90 ,  92  by moving it backwards in the direction of the arc. A further difference from the first embodiment consists in that arc slots  88   a  to  88   e  are offset relative to each other in such manner that when the distance between retaining rails  28   a ,  28   b  is smallest handle  80  engages in the radially outermost arc slot  88   a  and when the distance between retaining rails  28   a ,  28   b  is greatest, handle  80  engages in the radially innermost arc slot  88   e.    
     A third embodiment of seat bench transport device  24  according to the invention is presented in the plan views of  FIGS. 17 and 18  and in the detail illustration of  FIG. 19 . Unlike the second embodiment represented in  FIGS. 15 ,  16  and  17 , arc slot  88   a  for setting a minimum distance between retaining rails  28   a ,  28   b  is radially innermost, and arc slot  88   e  for setting a maximum distance between retaining rails  28   a ,  28   b  is radially outermost. 
     In the detail view in  FIG. 20 , a cross member  56  with a positioning disk  68  of a fourth embodiment of the seat bench transport device  24  according to the invention is shown. Positioning disk  68  is based on the first embodiment with four arc slots  88   a  to  88   d , each of which is connected to the respective neighboring arc slots  88   a  to  88   d  laterally. In contrast to the previous embodiments, however, in this embodiment L-shaped offsets are formed at the ends of the slots instead of securing drillholes  90 . Offsets  104  are arranged at the locking ends and are conformed radially outwardly from arc slots  88   a  to  88   d . They lead back in the opening direction with an end section for the respective arc slot  88   a  to  88   d  and their orientation is accordingly counterclockwise. Each end section forms the locking end limit stop  92 , against which handle  80  is pressed by the force of the helical spring. The opening side end sections  90  are arranged radially inwards relative to arc slots  88   a  to  88   d  and are aligned to extend at an angle to arc slots  88   a  to  88   d . In this way, inadvertent opening of retaining rails  28   a ,  28   b  is reliably prevented. In particular, this offset variant enables handle  80  to have the form of a threaded bolt, for example, which extends in vertical direction z and is movable along extended slot  82  of lever  78 . It is not necessary to insert and remove a securing pin  84 , and so a pushbutton mechanism  86  is also unnecessary. 
     A fifth embodiment of the seat bench transport device  24  of the invention  24  is shown in  FIGS. 21 and 22 . Unlike the previous embodiments presented in  FIGS. 2 to 20 , this embodiment does not have a gear assembly with two threaded rods  70 ,  72  and a gearwheel  66  that meshes with threaded rods  70 ,  72 . This fifth embodiment has a gear assembly with a link disk  106  and two guide bolts  108 ,  110 . The other elements of the device, such as the cross member  56 , pinion  62 , toothed segment  66 , positioning disk  68 , lever and handle  80  are the same as in the preceding embodiments, particularly the first embodiment as shown in  FIGS. 2 to 13  with regard to positioning disk  68  with four arc slots  88   a  to  88   d  that are in lateral contact with each other. 
     Link disk  106  is mounted so as to be rotatable about the axis of rotation of pinion  62 , which is permanently attached to link disk  106 . It has spiral slot pair that includes two spiral slots  112   a ,  112   b , which have a curve radius that becomes smaller towards the axis of rotation when viewed in the clockwise direction, and accordingly converge radially from the outside inwards when viewed in the clockwise direction. In this context, their radial inner end portions  114  are located approximately on a transverse axis of link disk  106  and their radial outer end portions  116  are located on a longitudinal axis of link disk  106 . As is shown in  FIGS. 21 and 22 , when a minimum separation between retaining rails  28   a ,  28   b  is set, link disk is oriented in transverse direction y, and when a maximum separation between retaining rails  28   a ,  28   b  is set, link disk is oriented in lengthwise direction x. Overall, the link disk is able to pivot through 270 .degree. 
     Guide bolts  108 ,  110  extend in vertical direction z and are individually connected to the middle of sliding portions  46  of retaining rails  28   a ,  28   b , the opposing long sides of which are extended in a triangular form for this purpose. They extend in vertical direction z and each is movable in one of the spiral slots  112   a ,  112   b . As is shown in  FIG. 21 , guide bolts  108 ,  110  are positioned in the area of inner end sections  114  of spiral slots  112   a ,  112   b  when the minimum separation between the retaining rails is set, and, as shown in  FIG. 22 , in the area of outer end sections  116  of spiral slots  112   a ,  112   b  when the maximum separation between the retaining rails is set. 
     Link disk  106  is controlled in the same way as in the preceding embodiments. A rotation of handle  80  or lever  78  is transmitted to toothed segment  66  and from this to pinion  62 , from where the motion is transferred to link disk  106 . Starting with retaining rails  28   a ,  28   b  at their closest position as shown in  FIG. 21 , when link disk  106  is rotated counterclockwise guide bolts  108 ,  110  are moved from the radially innermost position shown to the radially outermost position shown in  FIG. 22 . Because guide bolts  108 ,  110  are secured to sliding portions  46 , the rotary motion of link disk  106  is transmitted to retaining rails  28   a ,  28   b , which then execute a sliding movement in longitudinal direction x away from one another, as a result of which the distance between them increases. To move retaining rails  28   a ,  28   b  closer to one another, lever  78  must be turned in the opposite direction. 
     LIST OF REFERENCE NUMBERS 
     
         
           1  Outside device 
           2  Seat bench 
           4  Caster pair 
           6  Caster pair 
           8  Pallet 
           10   a, b  Seat rail 
           12  Seat 
           14  Seat 
           16  Seat 
           18  Seat support beams 
           20  Seat bench foot 
           22  Seat bench foot 
           24  Seat bench transport device 
           24 ′ Seat bench transport device 
           26  Chassis 
           28   a, b  Retaining rail 
           30  Displacement mechanism 
           32  Side member 
           34  Side member 
           36  Transverse member 
           38  Transverse member 
           40 ,  40 ′ Caster pair 
           42 ,  42 ′ Caster pair 
           44  Caster recess 
           46  Sliding section 
           48  Locking section 
           50  Limiter 
           52  Limiter 
           54  Seating space 
           56  Cross member 
           58  Rotation angle drillhole 
           60  Gearwheel 
           62  Pinion 
           64  Pivot angle drillhole 
           66  Toothed segment 
           68  Positioning disk 
           70  Threaded rod 
           72  Threaded rod 
           74  Actuating element 
           76  Axle pin 
           78  Lever 
           80  Handle (knob) 
           82  Elongated slot 
           84  Securing pin 
           86  Pushbutton 
           88   a, b , . . . Arc slot 
           90  End stop 
           92  End stop 
           94  Securing drillhole 
           96  Telescopic arm 
           98  Telescopic arm 
           100  Transverse arm 
           102  Radial slot 
           104  Offset 
           106  Link disk 
           108  Guide bolt 
           110  Guide bolt 
           112   a, b  Spiral slot 
           114  Inner end section 
           116  Outer end section 
         x Lengthwise direction 
         y Transverse direction 
         z Vertical direction