DE3841899A1 - SEAT ADJUSTMENT - Google Patents

Abstract

A position adjustable vehicular seat has lower rails (14) on which are slidable beams (12). One of the beams (12) has pivoted thereto (at 36) one end of a rear telescopically extensible sprung lock (34) and one end of a first telescopically extensible sprung lock (35). One of two upper seat supporting beams (16) has its rear end articulated (at 36) to one end of a link (24,40), the other end of which is articulated to the other end the lock (34). The first end of the one beam (16) is articulated by a pin-and-slot connection (30,32) to one end of a link (22), the other end of which is articulated to one end of a link (40), the other end of which is articulated to the other end of the lock (35). The lock (34,35) are remotely releasable and lockable to adjust the tilt of the seat. <IMAGE>

Description

The present invention relates generally to adjustable Vehicle seats and is particularly based on a mechanical seat support and adjustment unit, especially for use with adjustable Motor vehicle seats, directed.

Great efforts have been made in the development of devices has been made, the hiring of motor vehicle seats, esp special of the driver's seat, with an optimum of comfort comfort, comfort and safety allowed. Existing on actuators include purely mechanical systems, at which are adjusted by spring-loaded levers and bolts takes place, electrically operated devices in which screw elements along motor-driven screw spindles that, or a combination of these two. The purely mechani systems are preferred, mainly because they are at the bottom End of the economy scale because of its low cost, their easy installation and their greater inherent reliability stand. That is why there are many mechanical seat adjustments directions have been developed and in use.

Purely mechanical seat adjustment units rely on the body the weight of the seated person around an upward spring overcome and thus a desired change to get the seat position. When a bolt is released, the following results an adjustment of the seat position under spring pressure in the desired  Extent by the seat holder who is able, degree and direction the adjustment by shifting his or her body weight in relation to the adjusting device.

Existing mechanical seat adjustment units suffer from certain ten shortcomings. A source of difficulty in strut flowed devices lies in the variable pressure force of coil springs, which are typically used for this purpose be applied. A constant spring constant is known Lich an increasingly greater pressure force when the spring is together is pressed. So if the seat comes from a fully raised La is depressed, the owner (of the seat) wakes up send resistance, and near the fully depressed position according to the almost full compression of the spring, the Kör per weight of an individual lightweight is not sufficient be to push the seat further down because it is on a considerable spring force strikes. This difficulty is generally discussed in Many existing designs are overcome by an auxiliary hand handle is provided, d. H. a mechanical lever that usually is attached to one side of the seat and is operated to to lower the seat by increasing the size by lever Hand force is added to the weight of the seat holder to do so to achieve through full spring compression. However, since strength vehicles striving to become ever more compact, it becomes too taking difficult and impractical that for the auxiliary lever to provide the required space. On the inside of the front seats a central console is often provided, while on the Au there is little space between the seat and door panel on the outside of the seats,  to shrink the size of the motor vehicles. The Auxiliary lever also adds a visible mess to the inside Design of the vehicle and is therefore also aesthetic undesirable reasons.

For the above reasons, it has become desirable to have one spring loaded seat adjuster for use in Provide motor vehicle that is easier on an attitude al lein by body weight and body movement without manually operated Auxiliary lever reacts.

The present invention is directed to the foregoing needs, a seat adjuster with a base from two parallel rails for attaching to an egg ner seat mounting surface such as the floor board of a motor vehicle driving guest cell to be provided with a pair of lower support beams that slide lengthways along the rails, and a pair of upper straps to support the seat attached to them. Two transverse, parallel waves are on the lower Carriers stored and connect them in a fixed paral lelen distance. Each shaft carries a rocker arm and a pair of axially spaced lifting levers on the shafts are fastened and generally recoil radially from them ken. The upper straps have front ends that swivel with the Lifting levers are connected and of these between the radially outer ends are supported on the front shaft while the rear ends of the upper beams in the same way from Hubhe be supported on the rear shafts. One turn one wave raises or lowers the corresponding end of both  upper straps, with a seat supported by them tilting. A pull-out locking device is used as a connection between the outer radial end of the rocker arm on each shaft and one of the lower beams arranged. Each of the two bars mente is under spring pressure of a spring with a constant the spring constant in the direction of a linearly extending Position, so that the spring strives to expand, the wel le to which the individual rocker arm is connected, and likewise the lifting levers on the same shaft in one direction lift up the ends of the upper beams by these lifting levers be supported. The body weight of the seat holder works through the lifting levers and rocking levers to counter the spring load kick and telescopically press the bolts together. Either the front or back ends of the seat supportive straps can optionally by releasing the corre appropriate bar and shifting the weight of the seat holder be lifted away from this beam end, which allowed the spring tet to tighten the bolt and the corresponding end of the to lift the upper beam and the seat in the desired manner tilt. Each bolt is locked in the usual way in which it the two shafts hold against rotation to keep the seat in an exact s location. Each bar is individual with a Ka Belfreigabe or the like can be released and allows continued continuously independent adjustment of the front and rear seat height within the design limits of the device.

The device according to this invention improves on previous ones strikes by the geometry of the crank-like device in the The lifting and rocking levers on each shaft are optimized in this way  is that the mechanical advantage of the crank-like arrangement in the smaller the amount the compression spring is compressed, d. H. how the spring pressure increases accordingly. The net The result is that the spring force actually caused by the rocking and lifting levers to the upper beams and finally is transmitted upwards to the seat, almost constantly via the pressure Area of the spring remains.

In previous proposals it had been necessary in the pen choice to compromise to make it lightweight Allow seat holders to fully depress the seat and the To overcome spring force near its full compression. This solution has the use of a relatively weak spring requires a person weighing e.g. B. 46 kp could push the seat all the way down. On the other hand, this results a problem for heavier weight seat holders; e.g. a human weighing 82 kp would release at one elevated seating position an inadequate spring resistance fin that and thus a rapid sinking of the seat to a maximum depressed position.

This problem is overcome with the present invention which has approximately the same spring force over the seat adjustment range maintained; this allows a better compromise increasing spring pressure to provide a more appropriate seat support for to get heavyweight people, while these also with sol lighter weight remains manageable.

Yet another improvement in easy response is due to  such arranging the rear crank-like arrangement he is enough that the rearward directed against the seat back Force creates a component of force that leads to that downward directional body weight force vector is added and such helps push the rear end of the seat adjuster down ken. Specifically, the rear lift levers extend from the rear transverse wave in a generally backward direction and upward direction when they are in a maximum elevated position. The backward force against the seat back causes the rear lift levers to close down turn by turning the rear shaft that holds the rocker arm turns in the necessary direction to close the rear compression spring squeeze and the rear end (of the upper beam) to reduce. A lightweight seat holder can with the Niederdrüc of the rear seat section by helping bumps against the back of the seat. The trend to com compact and low-hanging motor vehicles drives the Driver and front passenger in an increasingly reclining position lung on the seats with the legs stretched forward, see above that it becomes easier to back against the back of the sit to press zes than to shift his body weight to one to apply vertically downward force and thus the To depress the device.

These and other features and advantages of the invention are discussed in individual described in a preferred embodiment, the will be explained with reference to the accompanying drawings. Show it:  

Fig. 1 is a side view of the seat adjusting device according to the invention,

FIG. 2 is a top view of the device of FIG. 1 with the central portions of the transverse shafts broken away and omitted.

Fig. 3 is a front view of a side of the apparatus along line 3-3 in Fig. 2,

Fig. 4 is a rear view of a side of the apparatus along line 4-4 in Fig. 2,

Fig. 5 is a side view as in Fig. 1 with the rear En de of the device in a raised position,

Fig. 6 is a side view as in Fig. 1 with the front En de of the device in a raised position,

Fig. 7a is a vector diagram showing the forces on the rear end of the seat adjusting device,

Fig. 7b is a vector diagram of a force acting against the seat back which helps to overcome the pressure of the rear spring, and

Fig. 8 curves of compression springs for a practical example of the invention.

Referring to FIGS. 1 and 2, the seat adjuster 10 has a pair of lower beams 12, the mounted rails 14 slide along, and a pair of parallel top, the seat support the beams 16. The lower supports 12 are connected at a fixed distance pa parallel to one another by two transverse shafts which comprise a rear shaft 42 and a front shaft 52 . The rear shaft 42 is rotatably supported by upstanding legs of two rear U-supports 54 , the base of which is connected by screw elements 56 to the lower supports 12 . Alternatively, a welded or riveted connection can take the place of the screw connection. The front transverse shaft 52 is rotatably supported in upright legs 58 a of front U-supports 58 , the bottom of which is attached to the associated lower supports 12 . A pair of lift levers are radially attached to and rotate with the shafts 52 , 42 .

A front angle bracket 26 and a rear angle bracket 28 are attached to each upper bracket 16 . Each angle bracket has the shape of an inverted L with a horizontal leg, which lies on and is fastened to the upper carrier 16 , and a vertical leg, which is articulated at articulation points 30 to the radially outer end of an associated lifting lever 22 , 24 . The front angle brackets 26 are supported on front lifting levers 22 , while the rear angle brackets 28 are supported on rear lifting levers 24 . The rear pivot points 30 are fixedly mounted to the angle brackets 28, while the front pivot points 30 are linearly displaceable within a recess 32 in each angle bracket 26 to a linear displacement of the upper support component to take on rotation of the Hubbebel. Alternatively, the recess can be provided at the rear articulation points for the same purpose. Each shaft 42 , 52 also carries a rocker arm 40 attached to it. A linearly operable rear latch 34 is articulated with its housing end to the lower support 12 at 36 and is articulated with its opposite rod end 38 to the radial outer end of the rear rocker arm 40 , the lower end of which is attached to the rear transverse shaft 42 . In the drawing, the rocker arm 40 and the lift lever 24 are shown as a one-piece crank-shaped element, but instead these can be separate lever elements that are axially spaced on the shaft 42 . The linearly operable Rie gel 34 has a rod 43 which is axially slidably arranged in a tubular Rie gel housing 46 , and a rear helical compression spring 48 which is axially between the bolt housing 46 and a retaining washer 50 which is fastened on the rod 43 near its end is squeezed. Under normal load, the latch 34 is in a telescopically extended position in which the rod 43 is pulled axially out of the housing 46 . The Rie gel 34 includes an internal device with respect to the Riegelge housing 46 through which the rod 43 is normally locked in the housing 46 against relative axial movement. The locking mechanism is released by remote control through a flexible cable (not shown), the distal end of which is connected to a fine control button or other actuating element for easy access by the seat holder on one side of the seat. A full description of the construction and operation of the preferred linear actuatable latch 34 is contained in the applicant's US Pat. No. 4,577,730, issued March 25, 1986, and is available from the undersigned as product no. MM65LOXX available.

Fig. 1 shows the rear end 20 of the device 10 in the fully depressed state, the rear latch 34 in a telescopically contracted position and the rear compression spring 48 in the state of maximum compression. When the rear latch is released from its normally locked position by remote control, the rod 43 is brought into an extended position by the coil spring 48 . The rod 43 rotates the rocker arm 40 and with it the rotatable rear shaft 42 and also the rear lift lever 24 counterclockwise to raise the rear ends (angle brackets 28 ) of the upper beams 16 to the raised position shown in FIG. 5 is. The rear part of the seat adjustment device 10 can be turned back into the depressed position according to FIG. 1 by releasing the rear bolt 34 again, a sufficient, downward force is applied to the rear end 20 to compress the rear compression spring 48 and thus linearly push the latch 34 together, and the latch device 34 is then locked in this state in order to hold the device in the depressed position.

The front end of the seat adjuster operates in a similar manner and has a front latch 35 similar to the rear latch 34 with a latch housing 46 hinged to the same lower bracket 12 at the hinge point 60 , as best shown in FIGS 3 can be seen, and a locking bar 43 , which is articulated at 62 to the radially outer end of the front rocker arm 40, which is fastened radially to the front transverse shaft 52 . Telescopic extension of the front bolt 35 under the action of the front compression spring 44 causes a rotation of the transverse shaft 52 according to FIG. 1 in a counterclockwise direction and rotates the front lifting lever 22 . Rotation of the lifting lever 22 in the counterclockwise direction lifts the front ends 18 of the upper carrier 16 into a raised position, as shown in FIG. 6. The front ends 18 can be rotated back to the depressed position shown in FIG. 1 upon release of the front latch 35 by applying sufficient downward force to compress the front compression spring 44 , the front shaft 52 and the front lift lever 22 clockwise to rotate, telescopically push the front latch together and finally lock it again to secure the device in the new position.

It is emphasized that the height of the front ends 18 and the rear ends 20 of the upper carrier 16 is independent of one another and is achieved by a selected release of the assigned latches 34 , 35 by means of individually operable remote control. As a result of this independent height adjustment, a seat connected to the upper brackets 16 can be tilted up and down front and rear, and by combining the front and rear settings in a swinging motion, the seat can also be raised and lowered without it has a significant impact on its tilting movements.

The compression springs 44 , 48 have as coil springs a constant spring constant and therefore a linearly growing resistance was when they are pressed together during the depression of the corresponding end of the seat adjuster 10 . In the fully raised position, the front and rear lift levers extend upward and rearward from the associated transverse shafts 52 , 42 . The body weight of the seat owner results in a downward force on the ends of the lifting lever, which aims to rotate the shafts together with the associated rocking levers 40 at the articulation points 30 in the clockwise direction. This is normally resisted by the locked state of the front and rear bolts 35 , 34 , which hold the device 10 and the seat supported by it in a selected position.

The downward force by the body weight, represented by the vector F ₁ , acts through a first lever M ₁ , represented by the lifting levers 22 , 24 , and is passed on by a second lever M ₂ , represented by the rocking lever 40 the linear acting latch / spring device, as indicated in FIGS. 5 and 6. Fig. 7a shows graphically the force vector diagram, according to which the resulting force F ₂ from the ratio of the lever M ₁ / M _{2 is transferred} to the locking bars against a Fe derdruckkraft F ₃ , as a function of the instantaneous angle α between the lever M ₁ and vertical vector F ₁ and the angle β between the lever M ₂ and the bar of the bolt (which is also essentially the axis of the compression spring).

The resulting axially directed pressure force F ₂ , which acts on the compression spring and is opposite to the spring pressure force F ₃ , results from

The spring pressure force F ₃ results from

F ₃ = dL · R

in which
dL the stroke length of the compression spring when compressed and
R is the characteristic spring constant of the compression spring.

The minimum force F ₁ required to compress the compression spring and thus lower the rear end of the seat adjuster 10 results from

The quotient in the expression given above grows almost linearly within certain ranges of the angles α and β , z. B. if α is between 45 ° and 0 ° and β = 90 ° ± 45 °.

The front and rear compression spring windings 44 , 48 are wound so that there is a constant spring constant which approaches the negative of the "average" slope of the F ₂ function within the given range and in the stretched state a spring pressure equal to that after directed below, resisting him. The increasing spring pressure F ₃ , which is ent when the compression spring is compressed during the depression of the device 10 , is almost balanced by the increasing mechanical advantage of the crank-like device with the lever ratio M ₁ / M ₂ , so that an approximately constant, downward force of the order of magnitude greater than F _{1 (min) will} fully depress the device. As seen from the spring end, the resultant force of the crank-like device decreases as the shaft rotates toward the depressed position by reducing the spring pressure force transmitted from the lift levers to the seat as much as the current one , force exerted by the spring on the rocker arm increases, the two trends thus cancel each other out almost and maintain an approximately constant upward force on the ends of the seat in all positions of the device 10 . Significantly, the rear end of the seat requires greater spring force because it supports a greater proportion of the seat owner's body weight. Fig. 8 illustrates the theoretical spring curves, which were calculated for the front and rear ends of the seat adjustment device, the rear compression spring 48 being selected to withstand a weight of 46 kp and the front compression spring having a downward weight of 14 kp. These theoretical curves are possible, ie practically realizable curves adapted, and the compression springs 48 , 44 are so wound that they correspond to these possible spring curves.

In previously known devices, the increase in spring force during compression ends in a compromise in the selection of the compression spring: if a light-weight person had to overcome the greatest spring pressure that was necessary to press the seat fully down, the spring force had to be at the maximum seat height can be reduced, resulting in inadequate support for heavier persons, which has resulted in them dropping with the seat when the rear latch 34 is released . By optimizing the geometry of the swing angle and the lifting lever, as described here, it will then be possible to use a stronger Druckfe the 48 than was customary in the past, and thus provide a better support for heavier people when the rear latch 34th is released without making it impossible for lighter people to never push the seat adjuster 10 . The same optimized geometry can be realized with the same improved results at the front end of the device in order to obtain a substantially identical spring force which opposes the weight of the seat holder over the adjustment range of the device provided at the front.

An additional new feature of the improved Sitzinstellvor device 10 is the arrangement of the rear lifting lever, so that the seat holder can help depress the rear end 20 by pushing backwards against the backrest of the seat, which is easy to achieve in a vehicle , if you lean back in the seat and press your feet against the chassis element or the fire protection cover of the passenger compartment. A considerable backward force can even be used by a lightweight person in this way. The effect of this is the tendency to rotate the seat about the front hinge points 30 and to depress the rear ends 20 of the device 10 . Fig. 7b shows a force vector diagram, according to which a vector F ₄ acts on the backrest, which acts at a typical angle in motor vehicles γ of 25 ° to the vertical resultant in a downwardly directed force components F ₅ on the end of the rear lifting lever 24 , which are shown in Fig. 7b as lever M ₁ . Vector F ₅ is added to the force vector F ₁ in FIG. 7 a, ie the weight of the seat holder increases the force F ₂ opposing the spring pressure in this way and facilitates the compression of the rear spring 48 . Providing such help is made possible by arranging the rear lift levers upward and backward from the rear shaft 42 so that the auxiliary force is added to the weight vector and both vectors F ₂ and F ₆ when the rear rocker arm 40 rotates against the spring pressure work together. Such additive effect is not possible if, for example, the rear crank-like device is arranged in reverse, so that the lifting levers stretch upwards and against the rear shaft 42 , and the crank-like device counterclockwise from the raised to the lowered position as shown . 5 and 6 rotates the Fig. It should be noted that this latter arrangement would be fully operational to push the rear end 20 down due to the weight of the seat holder, but it would not act as the previously described assistant when used against the backrest. Nonetheless, such an inverted crank-like device will take advantage of the optimized geometry described in connection with FIG. 7a to obtain a nearly constant spring force that acts on the rear end 20 . This optimization of the lever geometry is an improvement independent of the rearward orientation of the rear lift lever and the clockwise rotation of the rear rocker arm to lower the seat, as well as adding an active reinforcement or assistant to the seat holder's weight. The useful application of the seat holder's assistance increases the ability of a lightweight person to overcome the force of the rear spring 48 and therefore allows the use of even greater spring forces that better balance the weight of heavier people without significant inconvenience to lighter people.

The device is in the usual way with a suitable pawl or a suitable bolt for an adjustable locking tion of the lower support relative to the mounting rails 14 provided to allow adjustment of the seat position forward and backward along the mounting rails, for example, the distance between the vehicle seat and the steering wheel. A variety of locking devices for this Vorha ben is known and need not be described here.

The preferred training is only an example and only have been described for the purpose of clarification, and many changes rations, replacements and changes to the training described are included, which are in the ordinary technical knowledge, without that it deviates from the spirit and scope of the invention, which is limited only by the claims.

Claims (19)

1. Six-way seat adjuster, characterized by
a base,
lower beams that can be moved linearly on the base,
upper straps with a front and a rear end,
first axially displaceable telescopic locking elements which are arranged for actuation between the front end (of the upper support) and the lower support and are connected to these parts and which are released by remote control in order to adjust the height of the front support end relative to the base,
second axially displaceable, telescopic locking elements which are arranged for actuation between the rear end (of the upper bracket) and the lower bracket and are connected to these parts and which are released by remote control in order to adjust the height of the rear bracket end relative to the base,
third locking elements which are arranged for actuation between the first locking elements and the base and are connected to these parts and which can be released for a displaceable change in position of the lower and the upper supports relative to the base,
a seat on the upper beam in height, inclination and horizontal tale forward / backward position can be adjusted relative to the base. 2. Device according to claim 1, characterized,  that each locking element is a compression spring with an up to ih the constant position of the spring constant points and that a lever arrangement between the locking elements ten and the rear end (of the upper support) one approximately the same over the compression range of the spring to transmit permanent spring force to the upper beam. 3. Device according to claim 2, characterized, that the lever arrangement with an articulated joint is connected to the lower bracket and first and second levers has, which is at an angle to each other and radially from extend the joint, the first lever for a Actuation with the second locking element and the second He connected to the rear end (of the upper beam) and are arranged so that they are combined purely mechanically the linearly increasing spring force same when the spring is compressed so that the second lever has an approximately constant spring force transmits the rear end (of the upper beam). 4. The device according to claim 3, characterized, that the second lever extends from the hinge point ten and up in a raised position of the rear end (the upper beam) and extends due to a backward directed downward force that moves to the backrest a seat directed against the upper beam, the rearward force at least partially  the weight of the seat holder is added to the lower pushing the rear end (from the top beam) to facilitate while the second latch element is in a released Condition. 5. The device according to claim 2, characterized, that each locking element has a rod, one of which is En is attached to the base or to the lower support, while the other end axially through a bolt housing is movable, while a spring between the rod and the housing se is compressed, and the bolt housing reversed on lower support or attached to the base and that over Remote control releasable parts usually the rod ge lock against axial displacement and thus the position of the Soc Fix relative to the lower and upper beams gene. 6. The device according to claim 1, characterized, that the lever arrangement as a connection between each first and second locking element for transmitting an independent telescopic movement of the first and second locking elements into a change in height between each of the front or rear ends (the upper beam) and the base serves. 7. The device according to claim 1, characterized in that
that the lower beams have two parallel rails which are connected by two parallel, transverse shafts mounted in the rails,
Rocker arms and lifting levers attached to each of these shafts,
each of the first and second bolts connects a rocker arm on one of the associated shafts to the lower carrier,
the upper beam is supported between the shafts on the lifting levers,
wherein the telescopic expansion or contraction of the first or second locking elements is transmitted by rotating the associated shaft in a raising or lowering of the associated end of the upper support assembly. 8. Six-way seat adjuster, characterized by
a couple of parallel rails for attaching a seat assembly surface,
a pair of lower, longitudinally slidable beams,
a pair of parallel shafts, arranged perpendicular to the lower supports and connecting them to one another, the shafts being rotatably mounted in the lower supports,
a rocker arm and a pair of axially spaced lifting levers extending radially from the shaft,
a telescopically displaceable element as a connection between each a rocker arm and one of the lower beams and
a seat supporting assembly supported between the outer ends of the lift levers,
telescoping apart or contracting each of the telescopically slidable elements raises or lowers one end of the support assembly to tilt a seat support assembly. 9. The device according to claim 8, characterized, that a releasable locking element as a connection between at least one lower beam and one of the rails for optional longitudinal adjustment of the lower beams and the support arrangement for the seat along the assembled rails. 10. The device according to claim 8, characterized, that telescopic elements by a Federan order with constant spring constant in the direction of a stretched position are loaded, rocker arms and lifting levers appropriately dimensioned and arranged on each shaft are to an almost constant spring force to the associated ends of the seat support assembly via the compress to transfer area of the spring. 11. The device according to claim 10, characterized, that the rocker arm is aligned on the rear shaft is that a backward force against a backrest a seat is directed, which is on a seat support supports order, together with the weight of a seat holder works to depress the rear end (the  upper beam) to overcome the spring load. 12. The device according to claim 11, characterized, that when the rear end (the above rear carrier) the rear rocker arm from the rear shaft is directed downwards. 13. The apparatus according to claim 12, characterized, that when the rear end (the above rear carrier) lift levers on the rear shaft to the rear and are oriented upwards. 14. Seat adjustment device, characterized by
a lower bracket, suitable for attaching to a base,
an upper bracket with a front and a rear end for carrying a seat,
an axially telescopically movable locking element as an actuating connection between a rear end (an upper support) and a lower support, the locking element being releasable via a remote control to adjust the lifting of the rear end (the upper support) relative to the lower, and
a spring with a constant spring constant, which loads the locking element to its extended position, and further a lever arrangement between the locking element and the rear end (of the upper support), the lever arrangement being designed, an approximately constant spring force to the rear end ( of the upper beam) over the compression range of the spring. 15. The apparatus according to claim 14, characterized, that the lever arrangement is further arranged and designed is that a backward force against a backrest a seat is directed, which is on the upper beam supports, work together with the weight of a seat holder to depress the rear end (the upper Carrier) to overcome the spring load. 16. The apparatus according to claim 14, characterized, that the lever assembly at a hinge point of the lower Carrier is articulated, the lever arrangement first and second Has levers that are at an angle to each other and radially from extend the joint, the first lever for a Actuation with the locking element and the second lever with connected to the rear end (of the upper beam) and so on are arranged so that they combine mechanically advantageous alternate between raised and lowered layers of the back End (of the top beam) to the linearly growing spring force compensate when the spring is compressed, so that the second lever has an approximately constant Fe power to the rear end (of the upper beam). 17. The apparatus according to claim 14,  characterized, that the second lever is in a raised position of the rear end (of the upper beam) from the joint stretches back and top and due to a towards The downward directed force that is exerted on the backrest ne of a seat is directed, which is on the upper beam supports, the rearward force at least partially added to the weight of the seat holder to depressing the rear end from the top beam lighten while the latch element is in a clear given location. 18. Seat adjustment device, characterized by
a lower bracket, suitable for attaching to a base,
an upper bracket with a front and a rear end for carrying a seat attached to it,
a locking element as an actuating connection between the rear end (of the upper support) and the lower support, the locking element being releasable by remote control for adjusting the rear end (of the upper support) between a raised and a lowered position relative to the lower support, and
a spring with a constant spring constant, which loads the locking element on the raised position (the end of the upper support), and also a lever arrangement between the locking element and the rear end (the upper support), the lever arrangement being so formed and arranged is that in their union, in a purely mechanically advantageous manner, it alternates continuously between a raised and a lowered position (the rear end of the upper support) in order to compensate for the linearly increasing spring force when the spring is compressed, and an approximately constant spring force to the rear End (of the upper beam) transmits. 19. The apparatus according to claim 18, characterized, that the lever arrangement is further arranged and designed is that a backward force against the backrest a seat is directed, which is on the upper beam supports, work together with the weight of a seat holder to depress the rear end (the upper Carrier) the approximately constant spring force wind.