DE3737651A1 - DEVICE FOR A FOLDING LIFTBOARD - Google Patents

Abstract

In a folding-down tailboard for goods vehicles, a roller 51 is fixed to the cylinder rod of an inclined double-acting cylinder 22 somewhat above the cylinder longitudinal axis 26, against which roller the folded-up platform 66 bears in the stowed position when the cylinder rod is retracted. When the cylinder rod is then extended, a coupling lug 58 pivots clockwise about axis 13 and the roller 51 presses the platform 66 anticlockwise until to a position just before the vertical. The platform can now be pivoted further manually until it is supported by the coupling lug 58. Thereupon the cylinder rod is actively retracted, causing the platform to be pivoted into the horizontal, loading position. Stowing takes place in the reverse sequence. <IMAGE>

Description

The invention relates to a device according to the preamble of the main claim. Such devices are for example from the German patent 33 07 857 be became known. You are also through a prospectus of the applicant with the Title "Bär tail lift" became known.

In order to put such a device into operation, a mechanical lock is released and the platform package is lowered. The platform lock is then released. Two - mounted on either side of the device - springs pull the platform package in a location close to the neutral position. The focus of the platform package from the vehicle is on this side of the neutral position. The operator now manually tilts the platform package beyond the neutral position and the platform package then tilts with the second part of the platform still folded (in the case of devices in which the second sub-platform again consists of two sub-platforms, this applies equally) to a position beyond neutral location. The sub-platform swings around the swivel axis, which is usually identical to the third parallelogram articulation point. At the end of the movement, the first sub-platform strikes with a contact surface on a corresponding second contact surface of the coupling plate. Then the second sub-platform is unfolded by hand so that the accessible sides of the sub-platform are aligned. So that the folding, but also the unfolding, does not require a force exceeding the force of a person, a spring relief acts until shortly before the neutral position - as mentioned above. But spring relief also acts beyond the neutral position. This is achieved with two springs, which, however, is connected to the one horn of a boomeranglike deflection lever, which is pivotable about the third parallelogram pivot point. The disadvantage of this is the following:

• a) You need the bellcrank. It is intricately shaped and takes up space on the third parallelogram extending in the vehicle transverse direction Pivot point belonging axis away.
• b) One is limited in the spring force insofar as it is not arbitrarily high can do (because of different leverage) and you can not accommodate more than two feathers. This means that with heavier ones Underfold tail lifts must exert considerable forces by hand to do this Swing platform package over the neutral position. When careless Falling there is an increased risk of accidents.
• c) The tension springs interfere both in the folded in, as well as in the unfolded Condition of the platform and also interfere with some vehicle bodies in the Area of the rear loading sill.
• d) For the bellcrank, you have to separate from some truck bodies Make cuts so that when the underfold tailgate is raised the platform can also be raised to the level of the vehicle floor.
• e) For these reasons, the number plate on the truck is often difficult to attach. Often you can only use single-line number plates due to the height use, but because of the spring there is no space in the width. Quadra Table number plates require a deeper extension of the platform package, what comes at the expense of ground clearance / slope angle.
• f) Sometimes you have to help yourself by providing the license plate in the middle, but this is impossible when the truck is operated by a trailer.  
• g) The two bellcranks and the two springs bring weight with them. they not only bring the weight absolutely, but also on one Location that is significantly behind the rear axle of the vehicle and where weight is undesirable in many cases.

The object of the invention is to provide a device that is simple at least eliminates these disadvantages, hardly requires rethinking of the operating personnel, is practicable and manages with a minimum of parts.

According to the invention, this object is achieved by the characterizing part of the Main claims apparent features solved.

If the measures necessary according to the invention are listed only once Of course, this nevertheless means that they are at least in the two outside edge areas of the underfold tail lift are to be provided, since a tail lift in is essentially symmetrical to the vertical vehicle center plane.

The invention saves about 8 to 10 kg compared to the previous solution. There the springs and the bellcranks are eliminated, which has since been due to these components blocked space free. It is therefore no longer necessary to provide cutouts on the vehicle. The invention allows trailer operation because it does not give access to the trailer coupling blocked. Since the springs are missing, they cannot corrode. Both heavy, as well as light under-fold tail lifts can now be done with the same or at least Similar effort to be moved over the neutral position, both when Unfold, as well as when folding. The double-acting cylinder now used can have exactly the same dimensions as the single-acting one previously used Have locking cylinders. It only has another hydraulic connection.

The features of claim 2 achieve that both hydraulic connections for the cylinder does not move in the longitudinal direction of the cylinder, as the connections on the Housing can be provided. In addition, the focus of the cylinder consisting of piston rod, piston and housing closer to the vehicle.

Through the features of claim 3 you can achieve that the same cylinder can use for a wide variety of devices according to the invention. So far the length between the second and fourth parallel pivot point below  must be different, the differences are reduced by different lengths of the Rod head on. You can also better the lead on a rod head provide. Among other things, the piston rod has the task of absorbing axial forces bring and also to seal between the inside of the piston and her, which is a special Surface quality of the piston rod. In this respect, the rod head a comparatively raw part that only has different length requirements compensated. In addition, the folding platform collapses when folded back onto the front jump if it is folded towards the vehicle beyond the neutral position. This one The rod head, which is then subjected to bending, can withstand plops better than that Piston rod.

Due to the features of claim 4 least friction between the Bottom surface of the folding platform and the projection. Also the force is that of the Zylin who has to raise the folding platform to just before the neutral position, a minimum. Because when using a roller the projection on the lower surface not scraping, the surface remains intact.

Due to the features of claim 5, one is able to bring the projection - or when using a roll, the roll - more or less close to the fourth parallelogram articulation point, so that regardless of other parameters of the system, the folding platform is always sufficient can get close to the neutral position. You only have to attach and secure the roller block in the correct position on the rod head.

Due to the features of claim 6 you create for the very extended position of the cylinder the place for the third parallelogram articulation point. Naturally these points are not "points" in the mathematical sense, but include them parts necessary for such a joint.

Due to the features of claim 7, the elbow can be easily shaped and flat be so that they simply apply the thrust and pressure forces acting in their area can take. In addition, other, less favorable forces do not act on them, that would occur when touched.

Due to the features of claim 8, the tail lift behind the back leave the truck or trailer standing approximately vertically. In this condition  you can drive easily. This is very beneficial when between two on loading or unloading points is only a short distance and you are between these two Do not always want to fold the tail lift after finishing work. By the cylinder is able to level the platform again at the place of work and can then start unloading or loading again. Of course Lich the platform must be mechanically secured when driving in this position, since one cannot rely on the presence of hydraulic pressure that this con figuration maintained. These features make it possible for the platform not only available at a distance behind the vehicle. Rather, you could also with that Cylinder and possibly other, anyway with such underfold loading board existing gears, the platform like an end wall against the Press the rear edges of the truck body so that it would be closed from the rear.

By the features of claim 9 you can achieve that when you fix the Platt form does not have to be in a position other than the unfolding position and can then move from the unfolded position.

Due to the features of claim 10, a particularly simple first Ver is achieved locking device that is easily detachable and takes up practically no working time.

Due to the features of claim 11, the second platform also remains in a star stretched configuration relative to the first sub-platform, and the entire platform form then rises higher.

Due to the features of claim 12, a particularly flat is easy to achieve operating locking device that applies the necessary rigidity itself.

Due to the features of claim 13, the contact pressure can be approximately vertical standing folding tailgate in whole or in part through this with such under-folding Fully or partially apply the existing tailgate systems to the existing transmission.

The invention will now be described on the basis of exemplary embodiments. In the Show drawing:

Fig. 1 shows the schematic side view of a device according to the invention in a largely scale representation, with the respective drawn out loading of the folding and unfolding. Parts not to be considered here, such as the lifting cylinders, have been omitted here.

Fig. 2 is a detailed side view from the area of the third and fourth parallelo gram articulation point with the cylinder rod fully extended in a scale, partially sectioned representation.

Fig. 3 is a section along the line 33 in FIG. 2.

Fig. 4 is a side view of the rear part of a truck interchangeable body including the rear part of the chassis with the tail lift standing vertically.

Fig. 5 is an enlarged view according to arrow 5 in Fig. 4 with the first locking device Ver.

Fig. 6 is a view according to the arrow 6 in Fig. 4 with the second locking device.

Fig. 7 is a side view like Fig. 4, but with the tailgate folded.

Referring to FIG. 1, a first hinge axis 11 and a second hinge axis 12 are seen in front, which extend perpendicular to the drawing plane and the hinge axes 31 and 46 correspond to from the German patent specification 33 07 857. The second parallelogram handlebar device described there on the right is not described again here.

The device according to FIG. 1 also has a third hinge axis 13 and a fourth hinge axis 14 . The constructive realization of the articulated axes can be pin / socket connections, rolling element bearings or the like. A lifting arm 16 , which is a rigid arm, extends between the first joint axis 11 and the third joint axis 13 . It does not extend along the shortest path of the connecting line 17 between the joint axes 11 , 13 . Rather, it is inclined at an acute angle to this connecting line 17 and has a bend 18 at the bottom left, which is so high that the third hinge axis 13 is higher than the upper edge 19 of the lifting arm, in order to be able to better accommodate a folding platform 21 in its folded state . A cylinder 22 extends between the second hinge axis 12 and the fourth hinge axis 14 and can be pivoted about the second hinge axis 12 with its tab 23 provided at the top right. Its housing 24 is coaxial with the connecting line 26 between the second joint axis 12 and the fourth joint axis 14 . The housing 24 has a first connection 27 for a hydraulic pressure line. The hydraulic pressure is supplied to the top of a piston 29 via a bore 28 . A second connection 31 is provided facing downward in the lower region of the housing 24 . Hydraulic pressure can be supplied to a space 33 between the inner wall of the housing 24 and a piston rod 34 via a bore 32 . Pressure on the piston 29 through the bore 28 means that the piston rod 34 extends. Pressure on the annular surface of the piston via the second connection 31 causes the piston rod 34 to retract. In the lower left end of the housing 24 , a leading sealing sleeve 36 is screwed. The piston rod 34 has an outer end face 38 into which a threaded blind hole is machined coaxially with the connecting line 26 . A rod head 39 is screwed into it, which initially comprises an approximately 30 cm long, circular cylindrical rod 41 made of solid material, but which by no means has the surface properties of the piston rod 34 . The rod 41 has a diameter of approximately 5 cm and extends coaxially with the connecting line 26 . At its left end, as shown in FIG. 2, an offset 42 is welded to it, which has the shape shown in FIG. 2, shown to scale. The bend 42 , 40 mm thick overall, is made from a plate perpendicular to the plane of the drawing. From the crank 42 has a, from the connecting line 26 from angled down, first piece 43 , a parallel to the connecting line 26 extending second piece 44 and a fourth to the fourth hinge axis 14 extending third piece 46th The bend 42 is stiff. The construction creates a bay 47 which is sufficiently deep and long to accommodate the third hinge axis 13 and the hinge parts to be arranged around it. The third hinge axis 13 always remains a little above the connecting line 26 , because the force of the cylinder 22 cannot of course be infinitely large when the piston rod 34 is fully extended.

A bearing block 48 sits on the rod 41 . Its two bearing tabs 49 extend vertically at a distance upwards and support an approximately 28 mm wide roller 51 made of impact-resistant plastic, which is freely rotatable on an axis 52 . Fixed to the bearing block 48 , a first half-shell 53 is connected, which is supplemented by a second half-shell 54 to form a clamp, the half-shells at their edges merging into mutually parallel flanges 56 , which can be connected to one another by screws 57 , so that the roller 51 , as shown in FIG. 3, can be adjusted further to the left or right on the rod 41 and screwed there.

A coupling strap 58 connects the third joint axis 13 and the fourth joint axis 14 to one another. It is an elongated oval component. In FIG. 1, it has a stop surface 59 at the bottom left for a counter stop surface of a first sub-platform 62 of the folding platform 21 . Of course, seen in the vertical direction, the cylinder 22 and the lifting arm 16 lie side by side.

The first sub-platform 62 can be pivoted about the third articulation axis 13 by means of a conventional joint (not shown further), namely away from the lifting arm 16 according to the arrow 63 and towards the lifting arm 16 according to the arrow 64 . The arrow 63 indicates the direction of folding. The arrow 64 indicates the direction of folding. On which the third pivot axis 13 facing away from end portion 66 is pivotally connected via a coupling joint 67, the second wedge-forming the beginning of the drive-on part platform, which is not described separately. If, after the second partial platform 66 has been folded out, the abutment surfaces 68 , 69 lie against one another, then the inner surfaces 69 , 71 lying opposite one another in parallel in the folded state form a continuous plane, the tip 72 of the vehicle 73 ( FIG. 6) points away. The second sub-platform 66 has a lower surface 74 near the tip 72 , which lies opposite the peripheral surface 76 of the roller 51 .

This device works as follows: A mechanical safety device (not shown) is released in the usual way and the platform package is brought into position A. Pressure is now applied to the first port 27 . The fourth joint axis 14 pivots according to arrow 77 in a circular sector arc around the third joint axis 13 from its position B via position C etc. to position D. Correspondingly, the connecting line 26 (and the associated parts) also pivots upward about the second hinge axis 12 in the clockwise direction. This movement means a pivoting of the coupling plate 58 about the third hinge axis 13 from its somewhat vertical position into a position pointing to about eight o'clock. The roller 51 moves from its position E to its position F in an arc. In the E position, their catch 76 is even further away from the tip 72 than in the F position. The circumference 76 rolls on the lower surface 74 and the folding platform 21 is brought from its position A to position G. This position G is just before the neutral position and the rod 41 is extended to the maximum. Now you bring the folding platform 21 by hand over the neutral position to position H. The folding platform 21 pivots about the third hinge axis 13 in the still folded state until its counter abutment surface 61 has fallen onto the abutment surface 59 , as the position H shows. The third hinge axis 13 is - as shown in FIG. 2 - a distance from the connecting line 26 . Now a defined pressure is applied to the second connection 31 . The coupling plate 58 now moves counterclockwise to about six o'clock and this movement is followed by the folding platform 21 from its H position to the I position. Unlike ge, the stop surface 59 and the counter stop surface 61 remain in contact. In the approximately horizontal position, the second sub-platform 66 can now be folded out counterclockwise by rotation about the coupling joint 67 and - as usual - the folding platform 21 can now be adapted to the street level by moving the piston rod 34 more or less Tip 72 lies correctly. This process is known.

When folding in, the second sub-platform 66 is first folded back by hand. Then pressure is applied to the first connection 27 and from the starting position, which can be any position around the position C or B , the coupling strap 58 and thus also the folding platform 21 moves into the position H. Depending on the mounting conditions on the vehicle or the inclination of the terrain, the angle to the neutral position is approximately 15 to 30 °. The folding platform 21 is now moved by hand from the H position to the G position. The lower surface 74 falls on the peripheral surface 76 of the roller 51 . Now pressure is applied to the second connection 31 . The piston rod 34 retracts again and the roller 51 moves from the position F to the position E and in the process the position A is reached again. The roller is released by further retraction to the block of the piston 29 .

In Figs. 4 and 5 to the second embodiment can be seen which is known from the German patent specification 33 07 857 movement device 78. As in the first exemplary embodiment, the joint axes 11 , 12 , 13 and 14 are present here . Furthermore, the connecting lines 17 and 26 and the roller 51 . Fig. 5 shows that, for example, the fourth hinge axis 14 is realized by a bolt 79 which crosses the end region of the bend 18 and a complementary receptacle for this the coupling plate 58 . The stop surface 59 can also be seen. In the middle of it vertically above the connec tion line 26 here grows an eyelet 81 with a transverse bore 82 . A recess 83 complementary to the eyelet 81 is machined here in the middle of the counter abutment surface 61 . The block 84 bearing the counter abutment surface 61 has a transverse bore which is aligned with the transverse bore 82 in the state shown in FIG. 5, so that a secure plug 86 can be inserted through both bores.

Of course, behind the device shown in FIG. 4 is the same device that runs synchronously.

Due to the construction just described, the first sub-platform 62 is rigidly connected to the coupling bracket 58 so that it follows the pivoting movement thereof.

The second sub-platform 66 is in alignment with the first sub-platform 62 by means of at least one tab 87 in its position shown at the top left in FIG. 4. In the lower edge region of the second sub-platform 66 , a pivot pin 88 projects therefrom, which is rigidly connected to the second sub-platform 66 . It passes through a hole in the upper end region of the tab 87 . This crosses a parting line 89 between the first sub-platform 62 and the second sub-platform 66 . In the lower end region of the tab 87 , a bay 91 open to the edge, as shown in FIG. 6, is provided. This partially encloses a threaded shaft 92 of a star grip screw 93 , with which you can set the tab 87 in the position shown in Fig. 6. On the other side are the accessible inner surfaces 69 and 71 . In addition to this second locking device, two stops 94 , 96 prevent the second sub-platform 66 from pivoting counterclockwise relative to the first sub-platform 62 . The tab 87 therefore only needs to exert the force that the second sub-platform 66 pivots clockwise, which force is lower than that which the stops 94 , 96 have to exert.

This first locking device, which comprises the numbers 81 , 83 , 86 and the second locking device just described, as well as together with the usual lifting cylinders, not shown, makes it possible to achieve the configuration shown behind the rear edge of the vehicle in FIG. 4: the unfolded folding platform 21 is secured by the first locking device by the second locking device. The lifting cylinder then brings the device according to the invention into the position K in a known manner. By applying pressure to the first connection 27 , the coupling plate 58 comes approximately into its horizontal position, more precisely, into a position in which the inner surfaces 69 , 71 are approximately perpendicular. In position K , the device is mechanically secured to vehicle 73 . This fuse is not shown. The structure of the vehicle 73 can be firmly connected to its chassis 98 or it can be an interchangeable structure of the usual shape.

Those skilled in the art will see that it would also be possible to use the vehicle body with vertically positioned and interlocked partial platforms 62 , 66 as the rear closure of the vehicle. To do this, one would have to move the movement device 78 a little to the right and lift it a little higher with the lifting cylinders, so that the folding platform 21 can be pressed against the rear edge 97 in its deployed position. It is then locked again by locking devices, not shown.

Either way, the folding platform 21 does not need to be folded down again and again.

Claims (13)

1. device for an under-fold tail lift,
with a main cross member device which is movable in the longitudinal direction of a vehicle,
with an upper, first parallelogram articulation point on the cross member device,
with a lower, second parallelogram articulation point,
with a coupling strap,
with an upper, third parallelogram articulation point on the coupling plate,
with a lower, fourth parallelogram articulation point,
with a lifting arm between the first and third parallelogram pivot point,
with a tilt cylinder between the second and fourth parallelogram pivot points,
with a folding platform which comprises at least two sub-platforms, of which the first sub-platform can be swiveled about a swivel axis over a swivel angle which extends from the fully folded position to the fully unfolded position,
with a neutral position of the folding platform, if the center of gravity of the folding platform is approximately perpendicular to the swivel axis,
and with a lower surface on the folding platform, which is in the folded position of the folding platform above the part of the tilt cylinder that is movable in the longitudinal direction relative to the vehicle,
characterized by the following features

• a) The tilt cylinder is a double-acting cylinder.
• b) In the space between the lower surface of the folding platform and the longitudinally movable part of the tilt cylinder, an upward-pointing projection is attached, which is slidable in the longitudinal direction on the lower surface.
• c) When the movable part is extended, when the projection has a position close to the swivel axis, the folding platform is close to the neutral position.
• d) The projection is fixed on the movable part, but is adjustable in the longitudinal direction.

2. Device according to claim 1, characterized in that the housing of the Cylinder is articulated at the second articulation point. 3. Apparatus according to claim 1, characterized in that the movable part is a rod head that is connected to the free end of the piston rod of the cylinder is rigidly and coaxially connected. 4. The device according to claim 1, characterized in that the projection is a Roll includes, whose axis of rotation is perpendicular to the longitudinal axis of the rod head. 5. The device according to claim 1, characterized in that the role in one Roller bracket is mounted, which is attached to the rod head by means of partial shells. 6. The device according to claim 1, characterized in that the movable part has a bend before its fourth parallelogram articulation point, which in their bay in the extended state of the cylinder the area of the third Parallelogram pivot point. 7. The device according to claim 6, characterized in that the bend after is open at the top and also when the movable part is fully extended the area of the third parallelogram articulation point does not have the offset touched.   8. The device in particular according to one or more of the preceding claims, characterized in that the first sub-platform in its over the neutral Position tilted position rigid by a first locking device can be fixed relative to the third and fourth parallelogram articulation points. 9. The device according to claim 8, characterized in that it is tilted out Position is the unfolded position. 10. The device according to claim 8, characterized in that the first latches lungsvorrichtung is a lockable connector / eyelet device, one half firmly with the coupling plate and the other half firmly with the first partial plate form is connected. 11. The device according to claim 8, characterized in that the second partial plate form in its position unfolded to the first sub-platform by a second ver locking device can be fixed rigidly relative to the first sub-platform. 12. The apparatus according to claim 11, characterized in that the second Verrie gelungsvorrichtung is a flat swivel tab on a sub-platform is pivoted about parallel to the platform level that the pivot tab on the other end is detachably pivoted, and that the swivel tab bridges the folding joint between the first and second sub-platforms and on their not committed side. 13. The device according to one or more of the preceding claims, characterized records that the first and second parallelogram articulation point by a Be Movement device is movable in the longitudinal direction of the vehicle, which in turn is attached to the vehicle.