DE4004960A1 - Loading platform with railing for heavy goods vehicle - has intermediate position of deployment of railing which allows loading or unloading by pork lift truck - Google Patents

Abstract

The platform pivoted on an arm into and out of the plane of the floor of the vehicle, is associated with a safety railing in the form of a U-section hoop about 40 cm above, with a parallel pivot at the right angle of a triangle of tubular framing. The railing has a telescopic extension terminated in a cross-tube and is raised and lowered by a pneumatic jack (35), through an intermediate position for loading. - The pneumatic jack (35) is electrically connected to solenoid-operated valves (70, 71) supplied via a detector (67) which is in form of a quick silver switch.

Description

The invention relates to a device on a tail lift of a truck or the like, according to the preamble of claim 1.

Different versions of tail lifts are in use, be it as a rigid platform that is folded up vertically in the driving position, or be it as a folding platform that can be folded up and stowed under the vehicle frame becomes. Most of the time, the end edge is the rear edge the loading area of a truck or a trailer. The trailing edge can also be provided on a side edge of the loading area.

To accelerate the loading and unloading process, increasingly higher ones Stacks of boxes, boxes or pallets are moved and lifted by means of a tail lift the problem of securing is primarily against the environment slipping load. Especially when the tail lift is frequented by passers-by Areas, such as a commercial street. It also turns out increasingly the problem of operator safety against falling. Task of The invention is therefore a for a tail lift of the generic type to create suitable safeguards that do not hinder loading.  

This object is achieved by the characterizing features of claim 1.

According to the invention, a type of railing is provided that the three outer Pages assigned to the tail lift, but not attached directly to it but on the vehicle. In addition, the bracket can be pivoted so that it can easily be used can be stowed away or swiveled up for loading and unloading not to hinder the lowered tail lift.

A particularly simple and robust preferred embodiment of the invention is characterized by the features of claims 2 and 3, in particular according to Claim 5.

For those applications where the length of the side legs of the bracket alone would not be sufficient to secure the full length of the tail lift (i.e. with long tail lifts), the further training is recommended according to claim 4 or 6 or claim 21, which latter embodiment more comfortable is in use.

Relieving the weight of the Strap according to claim 11 and position fixation according to claim 9 (causing a rattle is avoided while driving).

The arrangement of the articulation points with respect to the first pivot axes according to of claims 12 and 13 has the advantage that the bracket is automatically pivoted up can be in the intermediate position (or in its vicinity) and then falls back into the working position (damped) due to its own weight. To a control device of simple construction is then sufficient.

Further advantageous refinements and developments of the invention result preferred from the remaining subclaims and the following description Embodiments of the invention with reference to the drawing.

It shows:

Fig. 1 is a side view in section of the rear part of a truck with a first embodiment of the invention.

Fig. 2 shows one of Fig. 1 corresponding view of a second embodiment of the invention in the working position,

Fig. 3 shows the apparatus according to Fig. 2 in the rest position,

Fig. 4 is a circuit diagram of a corresponding control device in a state of travel position,

Fig. 5 shows the circuit diagram of FIG. 4 in a state of loading position, wherein the detector indicates that the loading platform is lifted,

Fig. 6 shows the circuit diagram of Fig. 5, wherein the detector indicates that the tail lift is lowered.

Fig. 1 shows the rear part of a truck cut approximately along its central plane running in the longitudinal direction, but schematically simplified, since it does not matter. The truck has a loading area 11 , which ends rearward with a trailing edge 12 , and a box-like vehicle body with opposite side walls 13 (only one of which can be seen) and a roof wall 14 . The entire structure is seated on side members 15 , to which a cross member 16 is also attached. On this, a tail lift 17 is pivotally mounted in a manner known per se, so that its articulated arms 18 are only indicated. If the tail lift 17 is lowered, the articulated arms 18 pivot from the upward-pointing position into the position indicated by 18 ' . The inclination of the articulated arms 18 thus indicates whether the tail lift 17 is in the first position shown or is lowered to the road in a second position.

A mounting frame 19 is attached to the side wall 13 and comprises a base 20 and a vertical beam 21 . A bearing block 22 is attached to the base 20 just in front of the door rebate (the doors for closing the vehicle body are not shown), which forms a first pivot axis 23 for a bracket 24 , which is located approximately 40 cm above the loading area 11 . On the opposite, invisible side wall, a mirror-image mounting frame with a bearing block is attached, which also forms a coaxial first pivot axis.

The side leg of the bracket 24 shown in FIG. 1 is designed as a tubular frame which has the shape of a right-angled triangle, the first pivot axis 23 being arranged in the region of the right angle. The opposite catheter is formed by a first shorter tube segment 26 , which is followed by an arc 27, a long second tube segment 28 , which represents the hypotenuse of the triangle. A third tube segment 29 as a pathway completes the triangle. As a result, the side leg of the bracket 24 is very stable, with the second tube segment 28 extending parallel and horizontally over the loading tailgate 17 at a distance of approximately 80 cm above the loading surface 11 in the working position A shown in a strong extension. Here too, a congruently designed second side leg is mounted on the opposite side wall.

In each of the two second tube segments 28 , a further tube part 30 is telescopically displaceably inserted and the free ends of the tube parts 30 are connected by a cross tube, which thus forms the cross leg 31 of the bracket 24 . In the vertical viewing direction, the bracket 24 therefore has a U-shape with straight side legs 32 and the straight transverse leg 31 . With the help of the telescopically extendable tube parts 30 , the bracket length can be adapted to the length of the tail lift 17 . On the other hand, in the rest position R indicated by dash-dotted lines, the bracket 24 is still located within the vehicle body by previously inserting the tubular parts 30 into the second tubular segments 28 .

It is understood that this telescopic version by a rigid connection can be replaced if there is a correspondingly shorter tail lift.

Means are not particularly shown to clamp the pipe parts 30 with respect to the second pipe segments 28 or to lock them by means of pins, for example, since such measures are generally known.

A stop 33 is attached to the mounting frame 19 above the bearing block 22 (on each side of the vehicle) and has a stop surface approximately aligned radially with respect to the first pivot axis 23 , against which the first tube segment 26 can rest over a large area in the working position A of the bracket 24 . This abutment surface preferably also abuts against the bend 27 at the beginning of the second pipe segment 28 , with which the bracket 24 is supported very stably in the working position. As shown, the stop has 33 side cheeks, which at least overlap the first tube segments 26 , so that they are also secured against lateral slipping. The third tube segment 29 can rest against the rearward-facing vertical surface of the stop 33 in the rest position R of the bracket 24 .

As shown in FIG. 1, a pivot point 34 of a first actuating cylinder 35 is provided on the second pipe segment 28 , the other end of which is mounted on a pivot point 36 which is fixed to the vehicle and is screwed to the vertical beam 21 . The same arrangement is on the opposite side, not shown here.

The positions of the articulation points 34 and 36 are chosen such that they lie in an imaginary plane 38 with the most retracted piston rods 37 , which also extends through the first pivot axes 23 . In this dash-indicated intermediate position Z, which is also the dead center position of the swivel drive, the cross leg 31 is on the one hand sufficiently high above the (not shown) roadway so that the lowered tail lift 17 can also be loaded with the aid of a forklift and on the other hand lies in this Intermediate position of the center of gravity of the bracket 24 still behind the first pivot axes 23 (to the right in FIG. 1), so that the bracket automatically strives to swivel back into the working position A (solid lines) without complications.

In fact, the bracket 24 can never be pulled up exactly into this theoretical intermediate position Z by the first actuating cylinders 35 , because this would require an unnecessarily large tensile force. In fact, the bracket 24 rather reaches an intermediate layer ZP which is somewhat lower, but still ensures sufficient "headroom".

In order to bring the bracket 24 into the rest position R, it must be swiveled up by hand over the dead center position Z in the type of drive shown here, whereupon the switch 39 is actuated, so that the first actuating cylinders 35 then press the bracket 24 into the rest position R and hold tight. The control for this will be described later. The fact that the bracket 24 must be pivoted by hand over the dead center position is desirable insofar as an erroneous pivoting in is avoided in this way.

The base 20 and the vertical spar 21 can be attached directly to the side wall 13 of the vehicle body, or to an outer side plate belonging to the mounting frame 19 . The latter version is advantageous if the vehicle body does not have fixed side walls, but a tarpaulin cover. Furthermore, it is advantageous to cover the entire mechanism, that is to say the bracket 24 together with the actuating cylinders 35 , on the inside by protective plates (not shown) which are placed parallel to the side walls 13 . As a result, the device is secured against damage from tipping over. For this purpose, a further protective plate, which at least covers the transverse leg 31 of the bracket 24 in its rest position R with respect to the interior, is preferably also attached in parallel under the roof wall 14 .

In the embodiment of FIGS. 2 and 3, a similarly designed bracket 44 is provided, but its side legs 42 , which are designed as a tubular frame, have the shape of an obtuse-angled triangle and the cross leg 41 is rigidly fastened between the side legs 42 , which cannot be changed in length. The first pivot axes 43 are each located in the corner area between the lower, longer tube segment 45 and the short tube segment 46, which is at an acute angle thereto. The articulation point 48 for the respective first actuating cylinder 49 is located in the knee area, where the short tube segment 46 merges into the second longest tube segment 47 via the obtuse angle. In contrast to the previous example, its second articulation point 50 and the first pivot axis 43 are arranged so that they can be displaced essentially in the longitudinal direction of the vehicle, namely on the respective side leg 51 of a U-shaped pivot frame 52 . The side legs 51, which are congruent with one another, are connected to one another via the cross leg 53 , which is mounted parallel under the roof wall 14 and forms a second pivot axis 54 . For this purpose, a bearing block 55 , which is part of the mounting frame 56, is indicated in the figures.

As can be seen in FIG. 3, the side leg 51 engages over the tubular segments 46 and 47 of the bracket 44 in the rest position of the pivot frame 52 and bracket 44 , the two cross legs 41 and 53 being located just next to one another and the first pivot axes 43 approximately perpendicularly below them Distance of about 30 cm above the bed 11 are arranged.

A tube extension 57 is provided on each of the side legs 51 , which extends further in the direction of the loading area 11 than that end of the respective side leg on which the corresponding first pivot axis 43 is mounted. These tube extensions 57 each protrude between an outer wall and an inner guide bracket 58 , so that the side legs 51 are secured against impermissible transverse movements. A pawl 59 is pivotally mounted on the tube extensions 57 , which in the working position of the pivot frame ( FIG. 2) engages over a rear edge 60 of the mounting frame 56 and thus secures the pivot frame 52 in this position.

The pivoting frame 52 is preferably pivoted out and in by means of second actuating cylinders 61 (of which only one side can be seen) acting on the side legs 51 . These actuating cylinders 61 are articulated on the other end on the vertical spar 62 of the mounting frame 56 in a vehicle-fixed manner. Their control will be described later.

In this embodiment too, the movable mechanism in the region of the mounting frame 56 can be protected against damage by protective plates. It also prevents any objects from getting caught between the collapsing parts.

In FIG. 2, the operating position A of the bracket is shown 44 with strong lines, while the intermediate position Z (corresponding to those of Fig. 1) is indicated by broken lines. Here, too, the intermediate position Z represents a dead center position of the actuator because the articulation points 48 and 50 and the first pivot axes 43 lie in an imaginary plane 63 .

In the rest position of the swivel frame 52 ( FIG. 3), the first swivel axes 43 are just above the end edge 12 above the loading area 11 , but in the working position ( FIG. 2) behind the end edge 12 above the tail lift (which are not shown here in particular) is). A horizontal displacement of, for example, 40 cm is thus achieved.

Compared to the telescopic extension of the bracket 24 shown in FIG. 1, the swivel frame 52 has the advantage that its movement takes place without tilting and is therefore unproblematic, which is important when the bracket is used frequently. If the bracket can only be brought into the correct working position with difficulty, there is a risk that it will be left in the rest position for convenience. However, the constructive effort is larger and more expensive.

It is also conceivable to effect the telescopic extension from FIG. 1 with two actuating cylinders, which are accommodated in the second tube segments 28 . In order to avoid tilting, the best possible synchronization of the actuating cylinders is necessary, which can best be achieved with hydraulics. This variant (which need not be shown in particular) is therefore advantageous if a hydraulic system is already available on the vehicle for other purposes.

On the other hand, the first and second actuating cylinders 49, 61 (like the first actuating cylinders 35 ) can easily be operated with compressed air, which is necessary for the braking system in any truck and therefore does not require any special installation.

A control device is described for the operation of the apparatus shown in FIGS. 2 and 3 with the first two actuating cylinders 49 and the two second actuating cylinders 61 with reference to Fig. 4. If the parts shown in broken lines are omitted, the control device can be used in accordance with the operation of the device according to FIG. 1 with the first actuating cylinders 35 .

With an air pressure accumulator 65 is designated, which is charged in the usual manner, not shown here. The compressed air lines emanating from this are represented by double lines, in contrast to the single line of the electrical line, which leads from a power connection 66 via a detector 67 to the solenoid coils 68 and 69 of solenoid valves 70, 71 , the other ends on the ground line represented by a horizontal line are connected. The detector 67 can be designed, for example, as a mercury switch which is attached to an articulated arm 18 ( FIG. 1) and closes the current path as soon as the articulated arm reaches the horizontal position and pivots further down into the position indicated by 18 ' .

Two parallel line branches 72 and 73 go from the air pressure accumulator 65 to the two functional connections 74 and 75 of an OR valve 76 . As the ball symbol indicates, for example, an outflow of air through the functional connection 75 is blocked when air flows in through the functional connection 74 and pushes the ball (in FIG. 4) to the right. Accordingly, the ball is pushed to the left when the air flows in from the other side. The center connection 77 of the OR valve 76 leads parallel to the connections 78 on the piston rod side of the first actuating cylinder 49 (or 35 ).

In the first line branch 72 there is the series connection of a preload valve 79 , at whose outlet air with reduced pressure is present, and the first solenoid valve 70 , which opens the connection to the functional connection 74 in the currentless state shown. Air with reduced pressure thus reaches the right side of the pistons in FIG. 4.

In the second line branch 73 there is the series connection of a main changeover valve 80 and the second solenoid valve 71 , which connects the function connection 75 with a vent connection 81 leading to the atmosphere in the currentless state shown, while in the excited state ( FIG. 6) with the main changeover valve 80 .

The main changeover valve 80 is, as drawn, set up so that in the first position shown in FIG. 4, the so-called "driving position" F, the connections 82 of the first actuating cylinders 49 (or 35 ) remote from the piston rod and possibly also the connections 83 on the piston rod side connects second actuating cylinder 61 directly to the air pressure accumulator 65 . At the same time, the connections 84 of the second actuating cylinder 61 remote from the piston rod are connected to a further ventilation connection 85 via the main changeover valve.

As a result, the second actuating cylinders 61 ( FIG. 3) pull the swivel frame into the rest position. Furthermore, the first actuating cylinders 49 (or 35 in FIG. 1) press the bracket 44 ( 24 ) into the folded rest position, specifically because the air pressure on the left-hand side of the piston ( FIG. 4) predominates.

The above state is called the driving position because the bracket during the Driving the truck in the rest position R is held.

If the tail lift 17 is now put into operation, the main changeover valve 80 must also be switched to its second position, the "loading position" L, as shown in FIG. 5. The main switch valve 80 can be operated manually via a lever (as indicated) or via a solenoid (not shown), which is then controlled via the button 39 ( Fig. 1-3).

In the charging position L, the connections 78 and 83 are now connected to the vent connection 85 and the connections 84 to the air pressure accumulator 65 . The second actuating cylinders 61 thus pivot the pivot frame 52 into the working position ( FIG. 2). Since the tail lift 17 is folded from the vertical driving position into the horizontal loading position, but initially remains at the top, nothing changes in the position of the solenoid valves 70, 71 , that is, the reduced pressure at the connections 78 remains. However, since the pressure at the connections 82 of the first actuating cylinders 49 ( 35 ) has now disappeared, the piston rods are retracted and the bracket 44 ( 24 ) is thus pivoted out of the rest position R until its center of gravity lies behind the first pivot axes 43 ( 23 ) . From then on, the bracket weight supports the piston movement until the intermediate position Z is reached.

From here, when the bracket 43 ( 23 ) swivels further, the pistons are reversed, so that the piston rods are pulled out against the reduced pressure. Since the reduced pressure is only set to such a degree that the bracket weight is only partially compensated (weight relief), the bracket is able to move the pistons against the reduced pressure, with the result that the air now flows in the direction of arrow 86 ( Fig ., is derived from the sequence valve 79 to the atmosphere 5) and as indicated at 87. This "backward flow" is of course strongly damped, as a result of which the bracket 44 ( 24 ) slowly swivels into the working position.

If the tail lift 17 is now lowered so that it reaches a height range in which the detector 67 closes the circuit to the solenoid coils 68, 69 , the solenoid valves 70, 71 switch to the position shown in FIG. 6. Now the first solenoid valve 70 blocks the connection to the function connection 74 , while the second solenoid valve 71 connects the other function connection 75 to the air pressure accumulator 65 via the main changeover valve 80 . This unreduced air pressure thus reaches the connections 78 of the first actuating cylinders 49 , so that they swing the bracket 44 ( 24 ) up into the practical intermediate position ZP ( FIG. 1). This ensures that the bracket is automatically swung up so far that it does not hinder the loading and unloading of the tail lift.

However, as soon as the tail lift 17 (for example 10 to 20 cm wide) is raised, the detector 67 opens the circuit again, whereby the solenoid valves 70, 71 again assume the position shown in FIG. 5. However, there is now a different starting position insofar as the ball of the OR valve 76 was last pushed to the left (according to FIG. 6) and maintains this position, since even after the solenoid valve 70 has been switched back, no air flow in the direction of the arrow 88 ( FIG. 5) can occur because at this point the bracket 44 ( 24 ) is in the highest possible swivel position that can be reached by the actuator anyway. Rather, the bracket swivels back into its working position due to its own weight, this movement now taking place significantly faster because the air flowing back in the direction of arrow 89 (since the ball is on the left) can escape to the atmosphere via the solenoid valve 71 and the vent connection 81 .

As soon as the bracket 44 ( 24 ) has reached the working position and its pivoting movement has come to a standstill, there is no backflow and the ball is pushed to the right by the reduced pressure prevailing again, which is present at the function connection 74 , which means that the one in FIG state shown. 5 is present in which the arm 44 (24) only relieved of weight is in its working position.

In order to bring the bracket 44 ( 24 ) into the rest or driving position, it must first be swung up by hand (which is supported by the first actuating cylinder) until just above the intermediate position Z. Then the main switch valve 80 is switched to the driving position ( Fig. 4), whereby the full air pressure is applied to the ports 82 , which drives out the piston rods. This again causes a backflow 90 ( FIG. 4), which is discharged into the atmosphere in a strongly damped manner via the preload valve 79 . Thus, the bracket 44 ( 24 ) slowly pivots into its rest position.

Simultaneously with the changeover of the main changeover valve 80 , the connections 83 of the second actuating cylinder 61 also receive pressure, so that the swivel frame 52 also swings back into the rest position, provided the pawl 59 has been released. This is the starting position, the driving position.

For example, a valve marketed by the company FESTO with the type designation LR-1/8-F-7 can be provided as the preload valve 79 . The OR valve is offered by the same company under the designation CS-1/8.

Claims (34)

1. Device on a tail lift of a truck or the like, which tail lift is aligned approximately parallel to the floor of the truck bed in the loading position and between a first position adjoining the end edge of the truck bed and a second position lying on the roadway can be raised and lowered is stored, characterized,
that an approximately U-shaped bracket ( 24, 44 ) is provided in the top view of the tail lift, which is adapted to the outline of the tail lift ( 17 ) in the manner of a railing,
that the two bracket ends are each mounted on mutually coaxial first pivot axes ( 23, 43 ) which are aligned parallel to the end edge ( 12 ) of the truck bed ( 11 )
and that the bracket ( 24, 44 ) can be pivoted between a pivoted-out working position (A) extending substantially horizontally over the tail lift ( 17 ) and a substantially vertical rest position (R) stowed in the vehicle body. 2. Device according to claim 1, characterized in that the first pivot axes ( 23 ) above the truck bed ( 11 ) are arranged fixed to the vehicle. 3. Apparatus according to claim 2, characterized in that the working position (A) and rest position (R) of the bracket ( 24 ) are each defined by vehicle-side stops ( 33 ). 4. The device according to claim 3, characterized in that the side legs ( 32 ) of the bracket ( 24 ) are telescopically variable in length. 5. The device according to claim 3, characterized in that the side legs ( 32 ) of the bracket ( 24 ) are designed as a tubular frame, which in the direction of the first pivot axes ( 23 ) have the shape of a right-angled triangle, the first pivot axes ( 23 ) are arranged in the area of the right angles and the first tube segments ( 26 ), which form the counter-catheters, rest in the working position of the bracket ( 24 ) on stops ( 33 ) which are fixed radially to the first pivot axes ( 23 ), in which position the second Pipe segments ( 28 ) which form the hypotenuses extend essentially horizontally in each case above the sides of the tail lift ( 17 ). 6. Apparatus according to claim 4 and 5, characterized in that in the second pipe segments ( 28 ) further pipe parts ( 30 ) are guided telescopically, at the free ends of the cross leg ( 31 ) of the bracket ( 24 ) is attached. 7. The device according to claim 5, characterized in that the stops ( 33 ) have side cheeks extending in the pivoting direction, whereby the first tube segments ( 26 ) are secured against lateral slipping. 8. The device according to claim 2, characterized in that on the side legs ( 32 ) of the bracket ( 24 ) at a radial distance from the first pivot axes ( 23 ) attack the first actuating cylinder ( 35 ) which are articulated other fixed vehicle. 9. Apparatus according to claim 3 and 8, characterized in that the bracket ( 24 ) by the first actuating cylinder ( 35 ) against the stop ( 33 ) defining its rest position can be applied. 10. The device according to claim 3 and 8, characterized in that the first actuating cylinder ( 35 ) form the stop defining the working position. 11. The device according to claim 2 and 8, characterized in that the bracket ( 24 ) by the first actuating cylinder ( 35 ) in its working position (A) is supported to relieve weight. 12. The apparatus according to claim 8, characterized in that the mutually aligned articulation points ( 36 ) of the first actuating cylinder ( 35 ) and their mutually aligned articulation points ( 34 ) on the side legs ( 32 ) of the bracket ( 24 ) in an imaginary plane ( 38 ) lie, the first pivot axes ( 23 ) also being in this plane ( 38 ) in an intermediate position (Z) of the bracket ( 24 ) between the rest and working positions. 13. The apparatus according to claim 12, characterized in that the intermediate position (Z) is set such that the bracket ( 24 ) strives by its own weight to pivot into the working position (A). 14. The apparatus according to claim 12, characterized in that the piston rods ( 37 ) of the first actuating cylinder ( 35 ) in the working position (A) of the bracket ( 24 ) are most extended and retracted in the intermediate position (Z), and at a further pivoting of the bracket ( 24 ) beyond this dead center in the direction of the rest position (R) are extended again. 15. The apparatus according to claim 5 and 12, characterized in that the first actuating cylinders ( 35 ) on the second tube segments ( 28 ) are hinged at a distance from the transitions to the first tube segments ( 26 ). 16. The apparatus according to claim 14, characterized in that a control device is provided which comprises a detector ( 67 ) for detecting the position of the tail lift ( 17 ), the pressure with which the first actuating cylinder ( 35 ) in the sense of retracting the Piston rods ( 37 ) are acted upon from the working position of the bracket ( 24 ), controlled in such a way that the bracket ( 24 ) is pivoted up from the working position (A) towards the intermediate position (Z) as soon as the tail lift ( 17 ) is in the area is in its second position and that the pressure is reduced to such an extent that the weight ( 24 ) of the bracket ( 24 ) can only be swung back into the working position (A) by its own weight as soon as the tail lift ( 17 ) is above the aforementioned range. 17. The apparatus according to claim 16, characterized in that a main changeover valve ( 80 ) is provided, in its first position (F) the pressure regardless of the detector ( 79 ) unreduced the first actuating cylinders ( 35 ) in the sense of an extension of the piston rods ( 37 ) is supplied in order to hold the bracket ( 24 ) pivoted up via the intermediate position (Z) in the rest position (R), while in its second position (L) the pressure controlled by the detector ( 79 ) in the sense of retracting the piston rods ( 37 ) is specified. 18. The apparatus according to claim 17, characterized in that the first actuating cylinders ( 35 ) are operated by air pressure which is removed from an air pressure accumulator ( 65 ) and that the control device has the following features:

• a) from the air pressure accumulator ( 65 ) go two line branches ( 72, 73 ) to the two function connections ( 74, 75 ) of an OR valve ( 76 ), from the middle connection ( 77 ) a line to the piston rod-side connections ( 78 ) of the first actuating cylinder ( 35 ) leads;
• b) in the first line branch ( 72 ) is the series connection of a preload valve ( 79 ), at the outlet of which air can be removed with reduced pressure, and a first solenoid valve ( 70 ), which opens the first line branch ( 72 ) when de-energized, in the energized state State, however, blocks;
• c) is in the second line branch (73), the Hauptumschaltventil (80) followed by a second solenoid valve (71) which separates the function terminal (75) in the currentless state of Hauptumschaltventil (80) and connects with a leading to the atmospheric vent port (81) , in the excited state, however, connects the function connection ( 75 ) with the main changeover valve ( 80 );
• d) the first and second solenoid valves ( 70, 71 ) are excited as a function of the detector ( 67 ) as soon as the tail lift ( 17 ) is in the region of its second position ( 18 ' );
• e) the main changeover valve ( 80 ) in its second position (charging position) establishes the connection from the air pressure accumulator ( 65 ) to the second solenoid valve ( 71 ) and connects the connections ( 82 ) of the first actuating cylinder ( 35 ) remote from the piston rod to a ventilation connection ( 85 ).

19. The apparatus according to claim 18, characterized in that the main switch valve ( 80 ) in its first position (driving position) connects the piston rod-remote connections ( 82 ) of the first actuating cylinder ( 35 ) to the air pressure accumulator ( 65 ) and the line to the second solenoid valve ( 71 ) with the vent connection ( 85 ). 20. The apparatus according to claim 1, characterized in that the first pivot axes ( 43 ) above the loading surface ( 11 ) are arranged displaceable substantially in the horizontal direction. 21. The apparatus according to claim 20, characterized in that the first pivot axes ( 43 ) are each arranged at the ends of an approximately U-shaped pivot frame ( 52 ) which is pivotally mounted in an approximately vertical basic position about a second pivot axis ( 54 ) are arranged fixed to the vehicle at a distance parallel to the first pivot axes ( 43 ). 22. The apparatus according to claim 22, characterized in that the second pivot axis ( 54 ) is arranged just below the roof wall ( 14 ) of the vehicle body, the first pivot axes ( 43 ) being approximately perpendicular below the second pivot axis ( 54 ) in the basic position. 23. The device according to claim 22, characterized in that the pivot frame ( 52 ) can be fixed in the basic position and in a pivoted-out working position, the first pivot axes ( 43 ) in the basic position above the loading surface ( 11 ) and in the working position above the Tail lift ( 17 ). 24. The device according to claim 23, characterized in that on the side legs ( 51 ) of the pivot frame ( 52 ) act on second actuating cylinders ( 61 ) which are supported at the other end fixed to the vehicle. 25. Device according to one of claims 8 to 14 or 16 to 19 and according to claim 21, characterized in that instead of the vehicle-fixed articulation points of the first actuating cylinder ( 49 ), a linkage on the side legs ( 51 ) of the swivel frame ( 52 ) is carried out. 26. The apparatus according to claim 24, characterized in that the piston rods of the second actuating cylinder ( 61 ) are most extended in the working position of the pivot frame ( 52 ). 27. The apparatus of claim 18, 25 and 26, characterized in that the main changeover valve ( 80 ) in its second position (L), the piston rod-remote connections ( 84 ) of the second actuating cylinder ( 61 ) with the air pressure accumulator ( 65 ) and the piston rod-side connections ( 83 ) with the vent connection ( 85 ). 28. The apparatus according to claim 19 and 27, characterized in that the main switching valve ( 80 ) in its first position (F) the piston rod-side connections ( 83 ) of the second actuating cylinder ( 61 ) with the air pressure accumulator ( 65 ) and the piston rod-remote connections ( 84 ) connects to the vent connection ( 85 ). 29. The device according to claim 1, characterized in that the bracket ends are arranged on opposite side walls ( 13 ) of the vehicle body. 30. The device according to claim 29, characterized in that in the rest position of the bracket ( 24, 44 ) whose two side legs ( 32, 42 ) are arranged at a short distance parallel to the side walls ( 13 ) of the vehicle body and the cross leg ( 31, 41 ) is arranged at a short distance parallel below the roof wall ( 14 ) of the vehicle body. 31. The device according to claim 30, characterized in that at a distance from the side walls ( 13 ) and parallel aligned protective plates are attached, which cover the side legs ( 32, 42 ) of the bracket ( 24, 44 ) in its rest position. 32. Apparatus according to claim 31, characterized in that a further protective plate extends between the lateral protective plates, which is mounted at a distance from the roof wall ( 14 ) and aligned parallel thereto and the transverse leg ( 31, 41 ) of the bracket ( 24, 44 ) covered in its rest position. 33. Apparatus according to claim 22 and 32, characterized in that the side legs ( 51 ) of the swivel frame ( 52 ) behind the side protection plates and the cross leg ( 53 ) of the swivel frame ( 52 ) is arranged behind the further protection plate. 34. Apparatus according to claim 4 or 6, characterized in that the telescopically displaceable parts of the side legs or the other tube parts ( 30 ) can be extended and retracted by means of actuating cylinders.