GB2212132A - Apparatus for a folding-down loader tailboard - Google Patents

Description

r11 221213,2 IQ 1 Title.: Apparatus for a folding-down loader tailboard

This invention relates to an apparatus according to the introductory category of the principal Claim. Such apparatuses have been disclosed, for example, by German Patent Specification 33 07 857. They have. however, also been disclosed by a prospectus of the applicant having the title "Bgr Loader Tailboard".

In order to bring such an apparatus into operation, a mechanical securing device is released and the platform packet is lowered. The platform locking device is then disconnected. Two springs, mounted one on either side of the apparatus, pull the platform packet into a position just' before the neutral position. The centre of gravity oil the D-latform, packet is now situated this side of the neutral position, as seen from the vehicle. The operator now tilts the platform packet by hand beyond the neutral position and the platform packet then tilts with the second part platform still folded in (in those apparatuses in which the second part platform again consists.of two sub-platfoms, the equivalent applies), into a position beyond the neutral position. The part platform in this operation pivots about the pivot axis which usually is identical with the third parallelogram articulation point. At the end of the movement, the first part platform strikes with an abutment surface against a corresponding, second abutment surface of the coupling lug. The second part platform is then unfolded by hand, so that the walking sides of the part platforms are in alignment. In order that neither the folding-in nor the unfolding shall require a force exceeding the strength of one person, a spring load balancing takes place until just before the neutral position, as mentioned above. But a spring load balancing t&-.ces place also on the other side of the neutral position. This is achieved with two springs, which however are connected with the one horn of a boomerang-like deflection lever, w'-,iich is p-2..votal about the third parallelogram articulation point. Disadvantages of this arrangement are as follows:

a) The deflection lever is required. This is Of COMplicated form and takes up space on the axis extending transversely of the vehicle and forming part of the third parallelogram articulation point.

There is a limitation in the spring force, in that it cannot be made unduly large (on account of differing lever action) and also more than two Springs cannot be accommodated. This means that, in the case of heavy folding-down loader tailboards, considerable forces must be applied by hand in order to pivot the platform packet in either direction beyond the neutral position. In case of inattentiveness, there is increased risk of accident due to dropping.

M z c) The tension springs are a nuisance both in the folded-in and in the unfolded condition of the platform and,in many vehicle structures,also interfere in the region of the rear loading edge.

d) In some truck superstructures separate cut-outs must be provided for the deflection lever to enable the platform, in the raised condition of the folding-down loader tailboard, to be moved also to the level of the vehicle floor.

e) Por these reasons difficulties are often encountered in fittincthe number plate to the truck. Prequently, on account of the height available, only single-line number plates can be used, but due to the springs they do not have sufficient room in width. Square number plates require a lower mounting of the platform packet, which is obtained at the cost of ground clearance and slope angle.

f) Sometimes this must be overcame by providing the identification i ' which however is imDossible if the track is used 1 the centre.

with a trailer.

1 The two deflection levers and the two springs add weight. Not only do they add absolute weight, but it is at a point which lies considerably behind the rear axle.of the vehicie, where weight in many cases is undesirable.

The objective of the present invention is to provide an apparatus which in a simple manner at least eliminates these disadvantages, which hardly requires any rethinking by the operating personnel, 25 is practicable and manages with a minimum of components.

-4According to the invention there is provided an apparatus for a foldingdown loader tailboard, comprising a main transverse girder device which is movable in the longitudinal direction of a vehicle, an upper, first parallelogram articulation point to the transverse girder device, a lower, second parallelogram articulation point, a coupling lug, an upper, third parallelogram articulation point to the coupling lug, a lower, fourth parallelogram articulation point, a lifting arm between the first and third parallelgram articulation points, an inclined cylinder between the second and fourth parallelogram articulation points, a folding platform which contains at least two part platforms, of which the first part platform is pivotal about a pivot axis through an angle of pivot which extends from the fully folded-in position to the fully folded-out position, a neutral position of the folding platform when the centre of gravity of the folding platform is situated approximately vertically above the pivot axis, and a lower surface on the folding platform which, in the folded-in position of the folding platform, is situated above that part of the inclined cylinder which is movable relative to the vehicle in the longitudinal direction, characterised by the following features: a) b) the inclined cylinder is a double-acting cylinder, in the space between the lower face of the folding platform and the part of the inclined cylinder movable in the longidutinal direction, an upwardly orientated projection is fixed, which is slidable in the longitudinal direction along the lower face, when the movable part is extended, if the projection has a position near the pivot axis, the folding platform is situated just before the neutral position, d) the projection is stationary on the movable part, but is fixed so that it can be adjusted in the longitudinal direction.

POOR -CIUAL-ITY___ Q c Although the measures necessary according to this invention are listed here only once, this does of course mean however that they must be provided at least at the two outer edge regions of the folding-down loader tailboard, since a loader tailboard is basically symmetrical about the vertical central plane of the vehicle.

By the invention, about 8 to 10 kg weight is saved compared with the earlier solution. Since the springs and the deflection lever are dispensed with, the space previously occupied by these components becomes free. Therefore, no cut-outs any longer need to be provided at, the vehicle. The invention permits trailer operation, because it does not block access to the trailer coupling. Since the springs are omitted, they are not there to corrode. Both heavy and light foldingdown loader tailboards can now be moved with the same or at least similar application of force beyond the neutral position, both in unfolding and in folding-in. The double-acting cylinder now used can have exactly the same overall dimensions as the single-acting closure cylinder hitherto used. It simply has one additional hydraulic coupling.

Claims (1)

1. By the features of Claim 2 the result is achieved that both the hydraulic

   couplings for the cylinder do not move in the longitudinal direction of the cylinder, because the couplings can be mounted on the casing. Furthermore, the centre of gravity of the cylinder, consisting of piston rod, piston and casing, is now situated nearer the vehicle.

   By the features of Claim 3 the result is achieved that the same cylinder can be used for the widest variety of apparatuses according to this invention. If the length between the second and fourth parallelogram articulation points must be different, the differences are reduced by different lengths of the rod head. Purthermore, it is easier to provide the projection on the rod head. The piston rod does indeed have, amongst other things, the task of accepting axial forces and also of sealing between the piston interior and the rod, which requires a special surface quality of the piston rod. To this extent the rod head can be a COMDaratively crude component, which simply makes up different requirements in length. Also, although the folding platform simply falls down onto the projection when it is foll-ed beyond the neutral position towards the vehicle, this fall 15can be more effectively withstood by the rod head in bending than by the piston rod.

   By the features of Claim 4, minimum friction acts between the lower surface of the folding platform and the projection. Also, the force which the cylinder.must apply in lifting the folding platform until just belore the neutral position is a minimum. Since, when a roller is used, the projection does not scrape along the lower^surface, this surface remains intact.

   By the features of Claim 5 it is possible to bring the projection or, 25 where a roller is used, the roller, more or less near to the fourth 1 parallelogram articulation point, so that independently of other parameters of the system, the folding platform can alway's be brought sufficiently near to the neutral position. It is then only necessary to fit the roller block in the correct position in each case on the rod head and fix it there.

   By the features of Claim 6, for the fully extended position of the cylinder,space is created for the third parallelogram articulation point. These points are, of course, not "points" in the mathematical sense. but include those comDonents that are necessai-j for such a hinge.

   By the features of Claim 7 the cranked zone can be of simple form and flat, so that it can readily.accept the shear and compression forces acting in its region. Purthermore, other, more unfavourable forces then do not act UDon it, which would occur in the case of contact.

   By the features of Claim 8, the loader tailboard can be left standing generally upright behind the rear end of the tn-,ck or trailer. In this condition, it is quite possible to drive. This is very advantageous, if there is only a short distance between two loading or unloading 'stations and it is not always desired to fold down the tailboard when work has finished between these two stations. By using the cylinder it is possible, at the place of work, again to position the platform horizontally and immediately again start unloading or loading. Of course, when travelling in this condition, the platform must be mechanically secured, since it is not possible to rely upon the presence of a hydraulic pressure for maintaining this configuration. By these features it is possible not only to have the platform at a distance behind the vehicle, but it will also be oossible. with the cylinder and possibly other further drive devices, which are in any case present in such folding-down loader tailboards, to press the platform like a closure wall against the rear edges of the truck superstructure, so that this would be closed from the back.

   By the features of Claim 9 the result is achieved that, when fixing the platform, it is not necessary to bring it into a different position from the folded-out position, but it is possible to start from the folded- out Dosition.

   By the features of Claim 10, an especially simple first locking device is achieved, which can be easily released and demands virtually no 15 working time.

   By the features of Claim 11, the second platform also remains in a rigid, extended configuration relative to the first part platform and the entire platform then projects higher.

   By the features of Claim 12, an especially flat, simply operated locking device, which itself provides the necessary rigidity, is obtained.

   By the features of Claim 13, the application pressure of the generally vertically standing folding tailboard can be entirely or partly applied by this drive, which in any case is present in such folding- t down loader tailboard systems.

   The invention is now described by reference to examples of embodiment thereof. The Figures in the drawings show:

   Figure 1 1 a schematic lateral view of an apparatus according to this invention largely to scale and showing the positions of folding-in and folding-out. Those COMDonents that are not of importance here, such as for example the actuating cylinders, have been omitted.

   a detail lateral view of the region of the third and fourth parallelogram articulation points with cylinder rod fully extended, to scale and partly in section, Figure 3 a section on the line 3-3 in Figure 2, Figure 4 a lateral view of the rear part of a replaceable superstructure of a goods vehicle together with the rear Dart of the vehicle chassis with the tailboard standing vertically upright, Figure 5 an enlarged view along arrow 5 in Figure 4 showing the first locking device, Figure 6 a view along arrow 6 in Figure 4 showing the second locking device, Figure 7 a lateral view as Figure 4, but with the loader tailboard folded down.

   According to Fig. 1, a first hinge axis 11 and second hinge axis 12 are provided, which extend perpendicular to the plane of the drawing and correspond to the hinge axes 31 and 46 from German Patent Specification 33 07 857. The second parallelogram linkage described to the right thereof in that Patent is not described here again.

   The apparatus according to Pigure 1 has, furthermore, a third hinge axis 13 and fourth hinge axis 14. The constructional arrangement of the hinge axes may consist of journal-bush connectors, roller bearings or the like. Between the first hinge axis 11 and the third 10 hinge axis 13 there extends a lifting arm 16, which is a rigid arm. It does not extend along the shortest path of the connecting line 17 between the hinge axes 11, 13, but is inclined at an acute angle to this connecting line 17 and has a bend 18 at left bottom which is sufficiently high for the third hinge axis 13 to be higher than the upper edge 19.of the lifting arm to enable a folding platform 21 to be better accommodated in its folded-in state. Between the second hinge axis 12 and fourth hinge axis 14 extends a cylinder 22, which is pivotally attached at its right, upper lug 23 to the second hinge axis 12. Its easing 24 is coaxial to the connecting line 26 between the second hinge axis 12 and fourth hinge axis 14. The easing 24 has a first coupling 27 for a hydraulic line. The hydraulic pressure is fed through a bore 28 to the upper side of a piston 29. A second coupling 31 is provided, pointing downwards, in the lower region of the casing 24. Through a bore 32, hydraulic pressure can be fed to a chamber 33 between the inner wall of the casing 24 and a piston rod 34. Pressure on the piston 29 through the bore 28 means that the 1 piston rod 34 extends. Pressure on the annular surface of the piston through the second coupling 31 causes the piston rod 34 to retract. Into the left, lower end of the easing 24, a guiding sealing sleeve 36 is screwed in. The piston rod 34 has, at the outside, an end face 38, into which a threaded blind hole is machined coaxially to the connecting line 26. A rod head 39 is screwed into this blind hole, which rod head has first an approximately 30 cm long, circular cylindrical rod 41 of solid material, which however by no means has the same surface qualities as the piston rod 34. The rod 41 has a diameter of about 5 cm and extends coaxially to the connecting line 26. At its left- hand end according to Fig. 2, a cranked zone 42 is welded onto it, having the shape which can be seen true to scale in Fig. 2. Perpendicularly to the plane of the drawing, the cranked zone 42, in total 40 mm thick, is made from a plate. The cranked zone 42 has a first Diece 43, downwardly cranked from the connecting line 26, a second piece 44 extending parallel to the connecting line 26, and a third piece 46 extending to the fourth hinge axis 14. The cranked zone 42 is rigid. This arrangement.results in a bight 47, which is sufficiently deep and long to accommodate the third hinge axis 13 and the hinge components arranged around it. The third hinge axis 13 always remains slightly 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.

   1 A bearing block 48 is seated on the rod 41. Its two bearing cheek plates 49 extend upwards perpendicularly, spaced apart, and journal a roller 51, about 28 mm wide, of impact-resistant plastics, which rotates freely on an axle 52. A first half-shell 53, which is completed by a second half-shell 54 to form a pipe clamp, is firmly connected to the bearing block 48, the half-shells continuing at their edges into mutually parallel flanges 56, which can be connected together by bolts 57, so that the roller 51 according to Fig. 3 can be adjusted further to the left or right on the rod 41 and then firmly screwed on there.

   A coupling lug 58 connects together the third hinge axis 13 and the fourth hinge axis 14. This is an elongate, oval component. In Fig.

   19 it has at left bottom an abutment surface 59 for a counter-abutment surface of a first part platform 62 of the folding platform 21. The cylinder 22 and the lifting arm 16 are, of course, alongside one another in the verticaLdirection.

   The first part platform 62 is pivotal, by means of a conventional hinge not further illustrated, about the third hinge axis 13 in the direction of arrow 63 away from the lifting arm 16 and in the direction of arrow 64 towards the lifting arm 16. The arrow 63 denotes the unfolding direction, the arrow 64 the folding-in direction. At the end region remote from the third hinge axis 13, the second part platform 66, constituting the start of the extending part, is pivotally connected by a coupling linkage 67, which is not separately explained. When, after folding-out of the second part platform 66 through 180 0, the abutment surfaces 68, 69 bear against each other, then the internal surfaces 69, 71, which in the folded-in condition lie parallel to each other, form one continuous plane, the tip 72 7 9F pointing away from the veh-iele 73 -(Fig. 6). The second part platform 66 has, near the tip 72, a lower surface 74, which lies opposite the peripheral surface 76 of the roller 51.

   This apparatus operates as follows: in the usual way, a mechanical securing device, not shown, is released and the platform packet is brought into position A. Hydraulic pressure is now fed into the first coupling 27. The fourth hinge axis 14 now pivots according to arrow 77 in a circular are about the third hinge axis 13 out of its position B. through position C etc. to position D. Accordingly, the connecting r line 26 (and the parts associated therewith) also pivots about the second hinge axis 12 clockwise upwards. This movement implies a pivoting of the coupling lug 58 about the third hinge axis 13 from its approximately perpendicular position into a position at approximately 8 o'clock. The roller 51 moves from its position E in an are into its position F. In position E, its circumference 76 is still further away from the tip 72 than in the position F. The circumference 76 rolls on the lower surface 74 and the folding platform 21 is brought from its position A into position G. This position G is situated shortly before the neutral position and the rod 41 is extended to the maximum. The folding platform 21 is now brought by hand through the neutral position into position H. The folding platform 21 pivots, still in the folded-in condition, about the third hinge axis 13 until its counter-abutment surface 61 has fallen onto the abutment surface 59, a position H shows. The third hinge axis 13 is at a distance, as can be seen from Pig. 2, from the connecting line 26. A defined pressure is now applied to the second coupling 31. The coupling lug 58 now moves counter-clockwise into approximately its 6 o'clock position and this movement is followed by the folding platform 21 from its position H into position I. During this movement, the abutment surface 59 and counter-abutment surface 61 remain in contact, not as shown in the drawing. In the approximately horizontal orientation, the second part platform 66 can now be unfolded by hand by rotating aunticlockwise about the coupling linkage 67 and, in the usual manner, the folding platform 21 can now be adapted to the level of the road by greater or lesser extension of the piston rod 34, so that the tip 72 of the platform is correctly manDorted. This oDeration is known.

   In folding-in, the second part platform 66 is first folded back by hand. Then pressure is fed to the first coupling 27 and from the starting position, which may be any position around position C or B9 the coupling lug 58 and thus also the folding platform 21 moves into. oosition H. Depending upon the conditions of attachment to the vehicle or the slope of the ground, the angle to the neutral position 0 is about 15 to 30 The folding platform 21 is now brought by hand from position H into position G. The lower surface 74 falls onto the peripheral surface 76 of the roller 51. Pressure is now fed to the second coupling 31. The piston rod 34 again retracts and the roller 51 moves from position F into position E and thus again position A is reached. By further retraction fully home of the piston 29, the roller is released.

   j In Figures 4 and 5 for the second example of embodiment, the movement apparatus 78, known from German Patent Specification 33 07 857, can be seen. As in the first example of embodiment, the hinge axes 11, 12, 13 and 14 are also present here. Also 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 pin 79, which passes through the end zone of the bend 18 and a complementary seating for it of the coupling lug 58. The abutment surface 59 can also be recognized. An eye 81 having a transverse bore 82 projects from the centre of this abutment surface perpendicularly above the connecting line 26. In the centre of the counter-abutment surface 61 a recess 83, complementary to the eye 81, is formed. The block 84 carrying the counter-abutment surface 61 has a transverse bore which, in the condition illustrated in Fig. 5, is in aligw!ient with the transverse bore 82, so that a pin 86. which can be secured, can be pushed through both the bores.

   Behind the apparatus shown in Fig. 4 there is, of course, the same apparatus again, operating synchronously with it.

   By the constructional arrangement just described, the first part platform 62 is rigidly connected with the coupling lug 58, so that it 20 accompanies the pivotal movement of the latter.

   The second part platform 66 is, in its position shown at left top in Fig. 4, connected in alignment with the first part platform 62 by means of at least one lug 87. In the lower edge region of the second part platform 66, a pivot pin 88 projects from this platform, the Din 25 being rigidly connected with the second part platfor.m 66. It passes through a hole in the upper end region of the lug 87. This lug crosses over a dividing joint 89 between the first part platform 62 and the second part platform 66. In the lower end region of the lug 87 a slot 91, open towards the edge at the left in Pig. 6, is provided. This slot fits partly around a threaded shank 92 of a wing nut 93, by which the lug 87 can be secured in the position shown in Pig. 6. The inner surfaces 69 and 71 for walking on are on the opposite side. In addition to this second locking apparatus, two abutments 94, 96 prevent the second part platform 66 from pivoting anticlockwise relative to the first part platform 62. The lug 87 therefore only needs to apply the force for pivoting the second Dart platform 66 clockwise, which force is smaller than that which the abutments 94, 96 must apply.

   By this first locking apparatus, which comprises references 81, 83, 86 and by the just described, second locking apparatus and in conjunction with the usual actuating cylinders, not shown, it is DOssible for the configuration illustrated behind the rear edge of the vehicle in Fig. 4 to be achieved: the unfolded folding platform 21 is secured by the first locking apparatus by the second locking apparatus. By the actuating cylinders, the apparatus according to this invention is then brought in known manner into position K. By supplying pressure to the first coupling 27, the coupling lug 58 is brought approximately into its horizontal position, or more accurately into a position in which the inner surfaces 69, 71 are approximately vertical. In position K, the apparatus is mechanically secured to the vehicle 73. This securing is not illustrated. The superstructure of the vehicle V k Z 73 may be firmly connected to its chassis 98, or it may be a replaceable structure of the usual type.

   The skilled person will understand that it would also be possible, with the part platforms 62, 66 vertical and locked together, to use them as the rear closure for the vehicle superstructure. For this purpose, the movement apparatus 78 would need to be shifted a little towards the right and raised somewhat with the actuating cylinders, so that the folding platform 21 in its unfolded position can be pressed against the rear edge 97. It is then again locked there by locking 10 devices, not illustrated.

   Thus, in one way or another, the folding platform 21 does not always need to be folded back underneath.

   - CLAIMS Apparatus for a folding-down loader tailboard, comprising a main tranverse girder device which is movable in the longitudinal direction of a vehicle, an upper, first parallelogram articulation point to the transverse girder device, a lower, second parallelogram articulation point, a coupling lug, an upper, third parallelogram articulation point to the coupling lug, a lower, fourth parallelogram articulation point, a lifting arm between the first and third parallelogram articulation points, an inclined cylinder between the second and fourth parallelogram articulation points, a folding platform which contains at least two part platforms, of which the first part platform is pivotal about a pivot axis through an angle of pivot which extends from the fully folded-in position to the fully foldedout posittion, a neutral position of the folding platform when the centre of gravity of the folding platform is situated approximately vertically above the pivot axis, and a lower surface on the folding platform which, in the folded-in position C) of the folding platform, is situated above that part of the inclined cylinder which is movable relative to the vehicle in the longitudinal direction, characterised by the following features a) the inclined cylinder is a double-acting cylinder, b) in the space between the lower face of the folding platform and the part of the inclined cylinder movable in the longitudinal direction, an upwardly orientated projection is fixed, which is slidable in the longitudinal direction S._ I -19along the lower face, c) when the movable part is extended, if the projection has a position near the pivot axis, the folding platform is situated just before the neutral position, d) the projection is stationary on the movable part, but is fixed so that it can be adjusted in the longitudinal direction.

   2. Apparatus according to claim 1, characterised in that the casing of the cylinder is articulated to the second articulation point.

   Apparatus according to claim 1, characterised in that the movable part is a rod head, which is rigidly and coaxially connected with the free end of the piston rod of the cylinder.

   Apparatus according to claim 1, characterised in that the projection comprises a roller, the rotational axis of which is perpendicular to the longitudinal axis of the rod head.

   11 1-1, 1 Apparatus according to Claim 1, characterized in that the roller is journalled in a roller block which is fixed by part shells on the rod head.

   Apparatus according to Claim 1, characterized in that the movable part has, before its fourth parallelogram articulation point, a cranked zone which receives in its bight the region of the third parallelogram articulation point in the extended state of the cylinder.

   Apparatus according to Claim 6, characterized in that the cranked zone is open Upwards and,even in the fully extended condition of the movable part, the region of the third parallelogram articulation point does not touch the cranked zone.

   8. Apparatus especially according to one or more of the Dreceding Claims, characterized in that the first part platform, in its position tilted out beyond the neutral DOSitiOn, can be fixed by a first locking device rigidly relative to the thi-rd and fourth parallelogram articulation points.

   9. Apparatus according to Claim 8, characterized in that this tilted-out position is the folded-out position.

   10. Apparatus according to Claim 8, characterized in that the first 20 locking device is a plug-eye device capable of being secured, of which one half is firmly connected with the coupling lug and the other half is firmly connected with the first part platform.

   5, v 11. Apparatus according to Claim 8, characterized in that the second part platform, in its position unfolded relative to the first part platform, can be fixed by a second locking device rigidly relative to the first part platform.

   12. Apparatus according to Claim 11, characterized in that the second locking device is a flat pivoting lug, which is articulated to one part platform generally pivotally parallel to the plane of the platform, that the pivoting lug can be pivoted out releasably at the other end, and that the pivoting lug bridges across the folded joint between the first and second part platforms on the side remote from the walking face.

   13. Apparatus according to one or more of the preceding Claims, characterized in that the first and second parallelogram articulatio,n points can be moved by a movement device in the longitudinal direction of the vehicle, which device in turn is fixed to the vehicle.

   14. Apparatus for a folding-down loader tailboard substantially as discussed with reference to the accompanying drawLngs.

   Published 1989 a, The PaLentOffice.Statcliouse,66 7l1hghFoIbcrr-.Lond or. 'WAMR4TF.Further copies mkv be ObLained from The PatentOffiee. Sales Branch. St Mary Crkv. OrpingLon. Kent BR5 3RL. Printed by M"j]"plex teciriques ltd. St hlal"Y Cray. Kent. Cor.. 18'