EP0772533A1 - Dispositif de levage pour vehicules - Google Patents

Dispositif de levage pour vehicules

Info

Publication number
EP0772533A1
EP0772533A1 EP95900349A EP95900349A EP0772533A1 EP 0772533 A1 EP0772533 A1 EP 0772533A1 EP 95900349 A EP95900349 A EP 95900349A EP 95900349 A EP95900349 A EP 95900349A EP 0772533 A1 EP0772533 A1 EP 0772533A1
Authority
EP
European Patent Office
Prior art keywords
platform
articulation
hoist
parallel
lever
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP95900349A
Other languages
German (de)
English (en)
Inventor
Ingemar Svensson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ramsell Beatrice
Original Assignee
Ramsell Beatrice
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ramsell Beatrice filed Critical Ramsell Beatrice
Publication of EP0772533A1 publication Critical patent/EP0772533A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60P—VEHICLES ADAPTED FOR LOAD TRANSPORTATION OR TO TRANSPORT, TO CARRY, OR TO COMPRISE SPECIAL LOADS OR OBJECTS
    • B60P1/00—Vehicles predominantly for transporting loads and modified to facilitate loading, consolidating the load, or unloading
    • B60P1/44—Vehicles predominantly for transporting loads and modified to facilitate loading, consolidating the load, or unloading having a loading platform thereon raising the load to the level of the load-transporting element
    • B60P1/4414—Vehicles predominantly for transporting loads and modified to facilitate loading, consolidating the load, or unloading having a loading platform thereon raising the load to the level of the load-transporting element and keeping the loading platform parallel to the ground when raising the load
    • B60P1/445—Vehicles predominantly for transporting loads and modified to facilitate loading, consolidating the load, or unloading having a loading platform thereon raising the load to the level of the load-transporting element and keeping the loading platform parallel to the ground when raising the load the loading platform, when not in use, being stored under the load-transporting surface

Definitions

  • This invention relates to a hoist for vehicles of the type having a frame and a load carrier, comprising a vertically adjustable platform, a pivotable lifting arm which at spaced-apart articulation points is arti- culated to said frame and said platform, respectively, at least one linear motor by means of which the lifting arm is pivotable whilst moving the platform between upper and lower end positions, and a parallel-motion mechanism for maintaining the platform at an essentially constant angle to the horizontal plane when it is being raised or lowered.
  • hoists of the above type are long since known and are used for different types of goods vehicles, usually lorries, in order to facilitate loading and unloading.
  • such hoists have an operative loading position, in which the platform is extended in an essentially hori ⁇ zontal direction outside the load carrier, and an inope ⁇ rative transport position, in which the platform may be either retracted underneath the load carrier or swung up to an essentially vertical position in order to serve as, for instance, an openable door in a superstructure of the vehicle.
  • Prior-art hoists that can be moved in underneath the load carrier require an additional drive means for moving the hoist inwards and outwards, which renders the construction even more expensive as well as heavier.
  • the parallel-motion mechanism usually consists of two parallel pivot arms which are of equal length and are articulated to the chassis at two bearing articulation points on the chassis and two bearing articulation points on the platform rear edge facing the vehicle.
  • the pairs of bearing articula ⁇ tions on the chassis and the platform are located in planes that are substantially vertical and parallel.
  • the platform has to have a rather thick rear edge, which is disadvantageous in many respects.
  • a platform of considerable thickness is heavy, as well as expensive to manufacture.
  • the upper side of the platform will form a fairly large angle with the under- side, since the front edge of the platform has to be rather thin in order to facilitate the loading and unloading of goods.
  • the upper side of the platform will slope rather steeply towards the subjacent structure when the platform is placed thereon.
  • the goods is often loaded and unloaded with the aid of hand-drawn pallet loaders. These operations are much more difficult when the platform slopes steeply towards the subjacent structure.
  • a so-called scissors-type lifting table for moving the platform between a raised and a lowered position. This is achieved owing to the provision of at least two intersecting scissors arms, which are articulated to one another close to their cen ⁇ tres. At least one articulation of each pair of bearing articulation points provided where the scissors arms are connected to the platform and the frame, consists of a displaceable articulation bearing.
  • the bearing articulation points of the platform are located in a plane parallel to the plane of the platform, which obviates the inconveniences men ⁇ tioned above, i.e.
  • the platform can be rather thin, which is advantageous, at the same time as the distance between the bearing articulation points of the platform can be spaced apart by a considerable distance.
  • the plane of the bearing articulation points on the chassis has to be parallel to the plane of the bearing articulation points on the platform.
  • the bearing articulation points have to be arranged in pairs opposite to one another, which would make it neces ⁇ sary for the platform to be supported by a bracket struc- ture projecting outside the load carrier.
  • This invention aims at obviating the drawbacks of prior-art vehicle hoists and providing a hoist in which the platform is steadily supported in reliable fashion, despite a thin and, hence, light and less expensive design. At least this aim is achieved by a hoist as set forth in appended claim 1.
  • the invention is based on the insight that, due to the provision of the bearing articulation points of the platform in a plane at least essentially parallel to the plane of the platform, the distance between the bearing articulation points can be much longer than would have been possible with the bearing articulation points arranged at the rear edge of the platform, while at the same time the platform can be of an advantageously thin design.
  • the parallel-motion mechanism is equipped with a lifting arm extending between the chassis and the plat ⁇ form, a lever articulated to the lifting arm, as well as a parallel-motion arm articulated to the lever.
  • the lever may be connected to the platform, while the paral ⁇ lel-motion arm is connected to the chassis, and vice versa, i.e. the lever may be connected to the chassis, while the parallel-motion arm is connected to the plat ⁇ form.
  • the lever is angled, so as to avoid that the parallel-motion mechanism passes a dead-centre position when moving the platform between the upper and lower end positions.
  • a dead-centre position is passed when the two articulation points of the paral ⁇ lel-motion arm are on a line with the articulation of the lever to the lifting arm.
  • At least one of the bearing articulation points or the arti- culation of the lever to the lifting arm has to be a dis ⁇ placeable articulation bearing. It is optional which bearing articulation point is a displaceable articulation bearing.
  • bearing articulation point of the lifting arm, the lever and the parallel- motion arm may be designed as a displaceable articulation bearing. The movement of displacement should be directed towards and away from the other articulation of the same pair.
  • the invention further aims at providing, in accor ⁇ dance with a preferred embodiment thereof, a hoist in which the chassis, the fixing points thereon and the load-bearing structure of the hoist are not subjected to considerable stresses and, consequently, may be of a weaker, less expensive and lighter design.
  • Another aim of the invention is to provide a hoist which causes less changes of the inclination of the load carrier and the platform during loading and unloading and when moving the load on the platform, without the use of any additional supports reducing the effective load and making the hoist dearer. At least these aims are achieved by a hoist as set forth in the appended subclaims.
  • Yet another aim of the invention is to make the hoist of a preferred embodiment movable to and away from the area beneath the load carrier.
  • FIG. 1 is a side view of a preferred, first embodiment of the invention, full lines indicating the plat ⁇ form in a raised upper position, and dashed lines indicating an intermediate position and a lower position on the ground,
  • FIG. 2 is a side view of the hoist in the lower position with the two-piece platform folded up
  • FIG. 3 is a side view of the hoist when being moved in underneath the load carrier
  • FIG. 4 is a side view of the hoist in a completely re ⁇ tracted position underneath the load carrier
  • FIG. 5 is a side view of a second embodiment of the hoist according to the invention
  • FIG. 6 is a side view of a third embodiment of the hoist according to the invention.
  • FIG. 7 is a view of a forth embodiment of the hoist according to the invention. Description of Preferred Embodiments
  • Fig. 1 schematically illustrates the rear part of a load carrier generally designated 1.
  • the load carrier may be the platform of a lorry, which also comprises a chassis or frame 2 for supporting the lorry platform.
  • a hoist according to the invention which is generally designated 3, comprises a platform 4, a lifting arm 5 and a linear motor 6 in the form of a hydraulic cylinder.
  • the lifting arm 5 is, by articula ⁇ tions 7 and 8, articulated to, respectively, the platform 4 and the chassis 2 via a shifting element 9, which is shiftably arranged on a guide 10 supported by the chassis 2.
  • the piston rod of the hydraulic cylinder 6 is, by a first joint 11, connected to the lifting arm 5 at a point located between the articulations 7, 8.
  • the hydraulic cylinder 6 is provided with a supporting plate which, in the position shown in Fig. 1, is directed downwards and applied against the ground.
  • a second joint 13, arranged at the lower end 12, is, via a link arm 14, articulated to the guide 10.
  • the hoist is fitted with a parallel-motion mechanism which, in the embodiment shown, comprises a parallel- motion arm 15 and an angled lever 16 in addition to the lifting arm 5.
  • the lever 16 is L-shaped and has a long leg 16' and a short leg 16" forming an angle of about 90° with each other.
  • the lever is articulated to the lifting arm 5 by an articu ⁇ lation 18 and is, at its outer ends, articulated by articulations 19, 20 to, respectively, the platform 4 and one end of the parallel-motion arm 15 which, at its other end, is articulated to the shifting element 9 by an arti ⁇ culation 21.
  • the articulation 7 between the lifting arm 5 and the platform 4 is designed as a displaceable articulation bearing having a hinge pin displaceably arranged in a guide or slot 17 in the platform 4, the latter is movable upwards and downwards, whilst remaining at a constant angle to the horizontal plane.
  • the articulation 7 will come to occupy its outermost end position when the platform 4 is in an intermediate posi ⁇ tion, as shown in the Figure, whilst occupying a more retracted position below as well as above this level.
  • the parallel-motion mechanism is unsymmetrical, i.e. the distance between the articulations 8 and 21 is not the same as that between the articulations 18 and 20.
  • the chosen design of the parallel-motion mechanism enables the devising of a vehicle hoist in which the bearing articulation points on the platform are spaced apart and located in a plane that has at least a certain extent in parallel with the plane of the platform, and the bearing articulation points of the mechanism on the chassis are spaced apart and located in a plane that has at least a certain extent in the ver ⁇ tical direction, no dead-centre position being passed during the displacement of the platform between upper and lower end positions.
  • Figs 2-4 illustrate the function of the hoist when moved to the inoperative transport position beneath the load carrier 1.
  • the hoist is lowered onto the ground by retracting the hydraulic cylinder 6.
  • the plat ⁇ form 4 is divided into two parts, which are intercon ⁇ nected by a hinge (not shown) .
  • the platform can be folded up by pivoting the rear part of the plat- form over the front part thereof, as shown in Fig. 2.
  • a locking means (not shown) provided between the shifting element 9 and the guide 10 can be released so as to permit the shifting element to move along the guide 10.
  • the hydraulic cylinder 6 is, in the operative position, slightly inclined relative to a vertical line, such that the lower end of the hydraulic cylinder and the supporting plate 12 are situated slightly farther away from the vehicle than the first joint 11. If the hydrau- lie cylinder is extended by pushing out the piston rod to the position shown in Fig. 2, in which the locking means is released, the hydraulic cylinder will exert a forward- ly-directed force in relation to the vehicle. Since the lower end of the hydraulic cylinder is guided by the link arm 14, the hoist will be raised from the ground while the shifting element 9 is moved in under the lorry plat ⁇ form, and the joint 13 and the lower end of the hydraulic cylinder are pivoted upwards, as shown in Fig. 3. Final ⁇ ly, the hoist occupies a completely retracted transport position, as shown in Fig. 4, in which it takes up a minimum of space beneath the load carrier.
  • a lock may be arranged to lock the hoist in the transport position.
  • the inventive hoist has a number of advantages over prior-art hoists.
  • the hydraulic cylinder is positioned closer to the point of engagement of the load on the platform and this, combined with the fact that the stresses are transferred directly to the ground, results in that the chassis and the fixing points thereon are subjected to less stress.
  • the hoist can be of simpler, less expensive and lighter design.
  • the hoist will require less space, both in vertical and lon ⁇ gitudinal direction, in the inoperative transport posi ⁇ tion. Consequently, a greater number of vehicle types can be provided with a hoist, including certain types that have had too little space for conventional hoists.
  • Fig. 5 illustrates an alternative embodiment of the invention, which differs from that described above in that the lifting arm 5 is angled and that the point of engagement of the hydraulic cylinder 6 on the lifting arm is located farther ahead in relation to the vehicle.
  • the link arm 14 is connected to the shifting element 9, which means that the displacement of the hoist along the guide 10 of the vehicle has to be performed with the aid of a power-generating means (not shown) , preferably a hydraulic cylinder.
  • a power-generating means (not shown) , preferably a hydraulic cylinder.
  • the articulation of the lever 16 to the platform 4 consists of a displaceable articulation bearing 19.
  • the outer end portion 22 of the platform 4 is, at least to a certain extent, pivotable downwards about a hinge joint 23 in order to improve the application of the platform against the ground when in lowered position, thus faci ⁇ litating the loading and unloading of goods.
  • Fig. 6 illustrates a third embodiment of the inven ⁇ tive hoist in raised as well as lowered position.
  • the lever 16 is articulated to the frame by a displaceable articulation bearing 19, which travels in the slot 17 formed in the shifting element 9.
  • one end of the lever 16 is articulated to the platform by an articulation 21, i.e. it is the other way round compared with the embodiments described above.
  • the bearing articulation points 8 and 19 on the frame are located in an essential ⁇ ly horizontal plane, and the displaceable articulation bearing 19 is movable towards and away from the articu ⁇ lation 8.
  • Fig. 7 illustrates another embodiment of the inven- tion which rather resembles that illustrated in Fig. 6, the platform being shown in raised as well as lowered position.
  • the bearing articulation points 8, 19 of the chassis as well as the bearing articulation points 8, 21 of the platform are, however, fixed, and it is instead the articulation of the lever 16 to the lifting arm 5 that is designed as a displaceable articulation bearing 18.
  • Fig. 6 nor Fig. 7 shows a linear motor for raising and lowering the platform. It is to be understood that the vertical displacement of the platform can be performed in any suitable way, e.g. with the aid of a hydraulic cylinder resting on the ground, as shown in Figs 1-5, or with the aid of a hydraulic cylinder operat ⁇ ing between the lifting arm 5 and the frame 2.
  • the hoist need not be mounted at the rear of the vehicle but may well be mounted on a long side or even at the front.
  • the means for maintain ⁇ ing the position of the lower end of the hydraulic cylin ⁇ der need not necessarily be a link arm 14.
  • some sort of locking means may be arranged in the joint 11 which, depending on the angular position of the lift- ing arm 5 in the articulation 8, locks the hydraulic cylinder in a fixed position.
  • the hoist is provided with two lifting arms 5, two hydraulic cylinders 6, two link arms 14, two parallel-motion arms 15 and two levers 16.
  • the linear motor must not necessarily be a hydraulic cylinder, but use can also be made of pneumatic cylinders or screws.
  • the parallel-motion mechanism may, of course, be designed in many other ways.
  • the lever 16 may have other angles than precisely 90°, and the parallel-motion arm 15 may also be a linear motor, preferably a hydraulic cylinder to permit angular setting of the platform 4 in relation to the horizontal plane.
  • the lever articulated to the lifting arm at a central portion and to, respectively, the parallel-motion arm and the platform or the frame at opposite end portions instead of having the lever articulated to the lifting arm at a central portion and to, respectively, the parallel-motion arm and the platform or the frame at opposite end portions, as in the embodiments shown, one might have the parallel-motion arm connected to a central portion between the articulations to, respectively, the lifting arm and the platform or the frame.
  • the articulation 7 may advan ⁇ tageously be located as close as possible to the edge of the platform facing the load carrier.
  • the articulation of the lever 16 to the platform may then be situated outside the platform, i.e. rearwards of the vehicle.
  • the hydraulic cylinder 6 should be pivotable away from the inoperative transport position. This may be achieved by having a link arm 14 in the form of a hydrau ⁇ lic cylinder.
  • the joint 13 on the hydraulic cylinder 6 need, of course, not be arranged at the lower end of the cylinder. Further, the hydraulic cylinder 6 need not be connected to the lifting arm in the position shown in the drawings, but the connection may be arranged farther away towards the articulation 7 and may then be provided on the platform 4 itself.
  • the long hydraulic cylinders which are then required may suitably be telescopic in order to have a minimum length in retracted state.
  • the locking means acting on the shifting element 9 may be designed in many ways. For instance, the release and locking thereof may be brought about by pivoting the outer part of the platform in such a manner that the locking means will be released when the platform is folded into the position shown in Fig. 2 and will be locked when the platform is unfolded.
  • the parallel-motion mechanism described can also be operated with the aid of power-generating means that do not rest on the ground with one end.
  • the platform might be verti ⁇ cally adjustable with the aid of a hydraulic cylinder operating between the chassis 2 and the lifting arm 5.

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  • Engineering & Computer Science (AREA)
  • Jib Cranes (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)

Abstract

Un dispositif de levage pour véhicule de marchandises, du type à châssis (2) et porte-charge (1), comprend une plate-forme (4) réglable verticalement, un bras (5) de levage pivotant accouplé, au niveau de points d'articulation espacés (7, 8), au châssis et à la plate-forme respectivement, au moins un moteur (6) linéaire permettant de faire pivoter ce bras de levage quand la plate-forme se déplace entre des positions supérieure et inférieure, et un mécanisme (15, 16) à mouvement parallèle qui maintient cette plate-forme à un angle pratiquement constant par rapport à l'horizontale lorsqu'elle est élevée ou abaissée. Ce mécanisme à mouvement parallèle comprend un levier (16) et un bras (15) à mouvement parallèle reliés par une articulation (20). Le levier (16) est en outre accouplé au bras de levage (5) par une articulation (18), et à la plate-forme (4) ou au châssis (2) par une articulation (19). Le bras (15) à mouvement parallèle est accouplé par une articulation (21) à l'élément, châssis ou plate-forme, qui n'est pas relié au levier. De plus, une des articulations au moins (7, 8, 19, 21) consiste en un palier à articulation déplaçable.
EP95900349A 1993-11-03 1994-11-03 Dispositif de levage pour vehicules Ceased EP0772533A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9303618A SE9303618D0 (sv) 1993-11-03 1993-11-03 Fordonshiss
SE9303618 1993-11-03
PCT/SE1994/001040 WO1995012501A1 (fr) 1993-11-03 1994-11-03 Dispositif de levage pour vehicules

Publications (1)

Publication Number Publication Date
EP0772533A1 true EP0772533A1 (fr) 1997-05-14

Family

ID=20391620

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95900349A Ceased EP0772533A1 (fr) 1993-11-03 1994-11-03 Dispositif de levage pour vehicules

Country Status (4)

Country Link
EP (1) EP0772533A1 (fr)
AU (1) AU8119894A (fr)
SE (1) SE9303618D0 (fr)
WO (1) WO1995012501A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19719813A1 (de) * 1997-05-13 1998-11-19 Gerd Baer Faltbare Hubladebühne

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1480222A (fr) * 1966-03-25 1967-05-12 Hayon élévateur
FR2438008A1 (fr) * 1978-06-20 1980-04-30 Colas Des Francs Hubert Hayon elevateur perfectionne

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9512501A1 *

Also Published As

Publication number Publication date
SE9303618D0 (sv) 1993-11-03
WO1995012501A1 (fr) 1995-05-11
AU8119894A (en) 1995-05-23

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