WO2008130229A1

WO2008130229A1 - Lifting device for a vehicle

Info

Publication number: WO2008130229A1
Application number: PCT/NL2008/050218
Authority: WO
Inventors: Pieter John Van Mullekom; Bastiaan Lucas Van Baal
Original assignee: Pieter John Van Mullekom; Bastiaan Lucas Van Baal
Priority date: 2007-04-18
Filing date: 2008-04-16
Publication date: 2008-10-30
Also published as: NL1033716C2

Abstract

A lifting device for a vehicle comprises a lift platform (30) intended and adapted to receive an object for lifting, and a drive device (11,12,13,22) for displacing the lift platform in energized manner between a retracted position and an extended position. The lift platform extends displaceably from a displaceable intermediate frame (20) which is tiltable relative to an edge of the vehicle. Primary guide means (16,17) are provided which are intended and adapted to be received in the vehicle and which impose a primary path on the intermediate frame (20). Primary drive means (11,12,13) displace the intermediate frame (20) in co-action with the primary guide means between a retracted position and an extended position. The intermediate frame comprises secondary guide means (23) which movably receive the lift platform (30) and impose a secondary path. Secondary drive means displace the lift platform in co- action with the secondary guide means between a retracted position and an extended position.

Description

Lifting device for a vehicle

The present invention relates to a lifting device for a vehicle, comprising a lift platform intended and adapted to receive an object for lifting, and a drive device for S displacing the lift platform in energized manner between a retracted position located at least substantially inside the vehicle and an extended position located at least substantially outside the vehicle, wherein there is a height difference between the retracted position and the extended position.

0 Such a device can be applied particularly for loading and unloading an optionally driven invalid vehicle for the purpose of thereby increasing the action radius of the invalid vehicle. In addition, health, safety and ergonomic aspects impose increasingly more frequent and further limitations on the maximum weight of a cargo to be transferred if this has to be carried manually in and out of a vehicle. A lifting device S according to the invention also provides a solution for such applications.

Such a device is known from the European patent EP 911,007, wherein the device is specifically intended for loading and unloading of an invalid vehicle. The known device comprises for this purpose a lift platform supported by a pair of lifting the arms0 extending from the receiving vehicle. The lift platform can be carried by means of the energized lifting arms from a first position on a ground surface in a substantially vertical movement to loading floor level next to the vehicle. In this position the invalid vehicle can be moved inside, after which the lifting arms are further folded in together with the lift platform for the purpose of finally placing the lift platform in an5 upright orientation adjacently of the invalid vehicle.

A drawback of the known lifting device is however that the invalid vehicle here still has to be moved manually from the lift platform into the receiving vehicle. This represents a limitation, particularly for semi-invalid users. Furthermore, the lift0 platform is fully upright in the transporting position and thereby obstructs the view which, particularly in the case of a rear loader application, can be inconvenient. In addition, the freely suspended lift platform of the known lifting device requires a relatively heavy lifting arm construction if the device has to be suitable not only for relatively light wheelchairs but also for the considerably heavier motorized invalid vehicles which seem to be becoming generally accepted at the moment among the affected part of the population.

The present invention has for its object, among others, to provide a lifting device which, at least to a significant extent, obviates these and other drawbacks.

In order to achieve the stated object, a lifting device of the type stated in the preamble has the feature according to the invention that the lift platform extends displaceably from a displaceable intermediate frame which is tiltable relative to an edge of the vehicle, that primary guide means are provided which are intended and adapted to be received in the vehicle and which impose a primary path on the intermediate frame, that the drive device comprises primary drive means for the purpose of displacing the intermediate frame in co-action with the primary guide means in the primary path between a retracted position lying at least substantially inside the vehicle and an extended position lying at least substantially outside the vehicle, that the intermediate frame comprises secondary guide means which movably receive at least an outer end of the lift platform and impose a secondary path, and that the drive device comprises secondary drive means for the purpose of displacing the lift platform in co-action with the secondary guide means in the secondary path between a retracted position lying at least substantially inside the intermediate frame and an extended position lying at least substantially outside the intermediate frame.

Use is made here according to the invention of an articulated arrangement wherein the intermediate frame can be carried in and out of the vehicle and tilts over the edge of the vehicle in order to at least almost wholly bridge the difference in height, and the lift platform is displaceable in and out of the intermediate frame. From a halfway point in a loading cycle the intermediate frame supports on both sides on a ground surface in order to be able to absorb a load in optimal manner. In this situation the lift platform moves out of the intermediate frame so that an object for lifting can be received in substantially flat position, after which the lifting platform is carried with the object for lifting successively inside the intermediate frame, and the whole unit is pulled inside the vehicle. This takes place in at least substantially fully energized manner so that no manpower is required for the whole loading cycle, or for an unloading cycle in reverse sequence. Because the lift platform lies flat under the lifted object, the view out of the receiving vehicle is not therefore obstructed in any way at all. It has moreover been found in practice that it is possible to suffice with a relatively light construction for the lift system according to the invention in order to nevertheless handle a load in the order of several hundred kilograms, this being amply sufficient for normal applications, and particularly for motor-driven invalid vehicles.

In order to have the above described loading/unloading cycle take place to the greatest possible extent in jolt-free and gradual manner, a preferred embodiment of the lifting device according to the invention has the feature that the intermediate frame co-acts with the primary guide means for pivoting about a pivot shaft directed transversely of the primary path, and that said outer end of the lift platform co-acts with the second guide means for pivoting about a pivot shaft directed transversely of the second path. Both the intermediate frame and the lift platform are thus continuously able to adjust themselves to an actual angle of inclination.

In a particular embodiment the lifting device according to the invention is characterized in that the primary drive means comprise at least one linear actuator which can be attached optionally directly to the vehicle at a first outer end and is coupled to the intermediate frame at an opposite outer end. A linear actuator provides both pushing force and pulling force, and can thus energize both the loading cycle and the unloading cycle. For this reason a linear actuator requires only a relatively simple construction. The actuator can otherwise be of varying type within the scope of the invention and can for instance comprise a spindle or a hydraulic or pneumatic pressure cylinder. With adequate dimensioning it is possible in some circumstances to suffice with a single actuator, though it is also possible to apply a number of optionally lighter actuators, for instance on either side of the intermediate frame. In a further particular embodiment the lifting device according to the invention has the feature that the primary drive means comprise at least one driven winch which is intended and adapted to be connected firmly to the vehicle in optionally direct manner, and from which extends a cable, a free end of which is coupled to the intermediate frame. Such a winch is a relatively simple solution with a favourable cost price for the purpose of exerting a pulling force on the intermediate frame by means of the cable. The term cable must here be interpreted broadly within the context of the present patent application such that it is also understood to mean for instance a chain, cord or line. In order to enable both an inward and outward movement, two winches or two cables and drums on a shared winch can, if desired, be applied in a mutually opposed arrangement.

A preferred embodiment of the lifting device according to the invention has the feature however that the primary drive means comprise a tensioning spring coupled to the winch cable for the purpose of applying a bias during winding-up of the at least one winch, this bias being sufficient to displace the intermediate frame in an opposite direction when a winch tension falls away. If desired, it is possible in this case to suffice with only a single winch, and the tensioning spring is responsible for an opposed movement and energizing of the intermediate frame.

With a view to an adequate transmission of forces, a further preferred embodiment of the lifting device according to the invention has the feature that the primary guide means comprise guide rails over which guide members run at least substantially fittingly on at least both sides, which guide rails and guide members can be firmly attached on either side of the intermediate frame to the vehicle for reciprocation at a height above a vehicle floor and/or are connected to the intermediate frame. The rigidly mountable guide rails urge the guide members into the path thereof and are thus able to absorb the transverse forces occurring during a loading and unloading cycle. This is the main play offerees which occurs and which can thus be distributed in a relatively light, rigid construction. In a further particular embodiment the lifting device according to the invention herein has the feature that the guide rails comprise tubular profiles over which the guide members roll in at least substantially fitting manner on both sides with a concave guide surface adapted thereto. The tubular profiles are here applied mainly because of their bending strength. With a view hereto, a further particular embodiment of the lifting device according to the invention has the feature that the guide rails and the guide members are manufactured at least substantially from steel.

A further particular embodiment of the lifting device according to the invention has the feature that the intermediate frame, at least in the extended position thereof, is pivotable inside the primary guide at the first outer end and is able and adapted to support on a ground surface at the second outer end. By pivoting out of the primary guide and supporting on the ground surface the intermediate frame is able to fully bridge the height difference and take up the weight of the object optimally.

In order to simplify fitting of the lifting device in a vehicle, a further preferred embodiment of the lifting device according to the invention has the feature that the primary guide means extend from a base frame which moreover at least substantially comprises the primary drive means, which base frame can be fixed to a vehicle floor. The lifting device can be almost fully mounted in the base frame. The lifting device need then only be placed with the base frame in the vehicle and mechanically fixed therein and connected to an electrical system of the vehicle in order to perform a complete installation.

In a further preferred embodiment a lifting device according to the invention is characterized in that the intermediate frame comprises the secondary drive means. The secondary drive means can be relatively light in relation to the primary drive means, and can thus be placed relatively compactly in the intermediate frame. A further particular embodiment of the lifting device according to the invention herein has the feature that the secondary drive means comprise at least one linear actuator arranged between the intermediate frame and the lift platform. In order to facilitate driving of a vehicle on and off the lift platform, a further preferred embodiment of the lifting device according to the invention has the feature that the lift platform, at least in the extended position thereof, is mounted at the first outer end for pivoting relative to the intermediate frame and at an opposite free outer end is able and adapted to support on a ground surface. By pivoting relative to the intermediate frame, the lift platform can thus take up a smaller angle of inclination, and even lie almost completely flat. A vehicle can hereby be moved without difficulty on and off the lift platform. In order to here enhance extending of the lift platform, a further particular embodiment of the lifting device according to the invention has the feature that the lift platform is provided on an underside of a free outer end with rolling means for rolling support on a ground surface therewith. The lift platform is thus able to roll easily into position while negotiating possible small obstacles.

In order to secure a vehicle or other load on the lift platform, a further particular embodiment of the lifting device according to the invention has the feature that the lift platform is provided on a carrying side with an adjustable bar. The bar is here set just behind the object so that the object can support thereagainst in an inclining position of the platform, and is thereby held in place.

In order to facilitate getting into and out of an invalid vehicle to be lifted, a further particular embodiment of the lifting device according to the invention has the feature that on opposite longitudinal sides the lift platform comprises an upright part with an at least substantially flat elongate support part extending therefrom in a transverse direction. The support part forms as it were a step on which it is possible to step in and out.

In order to compensate a possible remaining height behind the lift platform and to enable a gradual driving on and off with an invalid vehicle, a further particular embodiment of the lifting device according to the invention has the feature that the lift platform comprises at a free outer end a tiltable bridge part which is pivotally connected thereto and which in a folded-out position bridges a remaining height above a ground surface and which in a folded-in position closes the lift platform. For the purpose of a durable whole and a light construction a further particular embodiment of the lifting device according to the invention has the feature that the lift platform is manufactured at least substantially of aluminium and that the lifting device otherwise comprises at least substantially parts of stainless steel. The relatively lightweight aluminium here limits the overall weight of the device, while the stainless steel parts impart strength to the whole but nevertheless retain a moisture resistance.

The whole device can be operated fully automatically. With a view hereto a further particular embodiment of the lifting device according to the invention has the feature that a control device is provided which in a first mode controls the primary and secondary drive means successively in an outward movement and in a second mode impose an inward movement on successively the secondary and primary drive means. If desired, an optionally wireless operating unit can be coupled to the control device with which a user can set the device into one of the two modes or bring it to a stop.

Particularly in the unlikely case that the height difference is smaller than normal, for instance if the vehicle is placed against a raised pavement, a smaller height difference can be bridged, hi order to protect the device against overload in such a case a further particular embodiment of the lifting device according to the invention has the feature that the control device comprises at least one touch-sensitive end sensor which is arranged close to a free outer end on an underside of the intermediate frame and which, when actuated, generates an electronic signal, upon which the control device interrupts the outward movement. As soon as the intermediate frame has reached the ground surface and the end sensor is actuated, the control device thus deactivates the drive prematurely. The same applies in a further particular embodiment of the lifting device according to the invention which is characterized in that the control device comprises at least one touch-sensitive end sensor which is arranged close to a free outer end on an underside of the lift platform and which, when actuated, generates an electronic signal, upon which the control device shuts off the outward movement. This also provides safety for obstacles and persons possibly present in the vicinity. In order to avoid a person possibly being trapped between separate parts of the lifting device during an inward movement thereof, a further particular embodiment has the feature according to the invention that the control device comprises at least one touch- sensitive safety sensor which is arranged on a front side of the lift platform and/or on a front side of the intermediate frame and which, when actuated, generates an electronic signal, upon which the control device interrupts the inward movement. This also contributes toward the safety of the lifting device as a whole.

The invention will now be further elucidated on the basis of two exemplary embodiments and an associated drawing. In the drawing: figures 1 A- 1 C show a first exemplary embodiment of a lifting device according to the invention in successive stages of use; and figure 2 shows a perspective view of a second exemplary embodiment of a lifting device according to the invention in a fully extended position. The figures are drawn fully to scale and corresponding parts are designated as far as possible in the figures with the same reference numeral.

The first exemplary embodiment of the lifting device according to the invention is shown in perspective in figures IA- 1C in successively a fully extended position, an intermediate position and a fully retracted position. The device comprises a base frame 10 of stainless steel with a length and width respectively in the order of 1 SO to 180 cm and 90 to 120 cm, which is adapted to a normal inner dimension of a transport vehicle and which can be fixed on a loading floor of a transport vehicle and is fully accommodated in a loading space thereof. Base frame 10 comprises primary drive means of a drive device in the form of a winch 11 with a steel cable 12, a free end of which is coupled to an intermediate frame 20. A winch drum 11 of the winch is here driven by an electric motor 13 with a suitable drive power. Winch cable 12 runs round over a number of pulleys 14 in base frame 10 and is fastened to both sides of intermediate frame 20. A tensioning spring 15 arranged in base frame 10 and winch cable 12 is hereby also tightened. A sufficiently strong steel cable is applied in this example as winch cable 12. Base frame 10 also comprises primary guide means in the form of a pair of guide rollers 16 for receiving thereon an underside of intermediate frame 20, and a pair of guide rails 17 arranged on either side of intermediate frame 20 at a height above an underside of base frame 10. Guide rails 17 are about 1.70 m long and comprise in this example thick-walled tubular profiles of ST 37-2 hard steel with a radius of curvature of about 40 mm and a wall thickness of about S mm, this being sufficient to give no bending of any significance, or hardly so, in the case of a load up to several thousand Newton.

Intermediate frame 20 is provided with guide members in the form of pairs of guide rollers 21 between which the guide rails 17 are enclosed. Guide rollers 17 are manufactured from sliding bearing steel manufactured with a concave surface which runs practically without resistance over guide rails 17. Winch cable 12 engages close to the pairs of guide rollers on intermediate frame 20 on which the pairs of guide rollers 21 are mounted rotatably about an axis. Intermediate frame 20 is thus guided in freely pivotable manner about a pivot shaft directed transversely of a guiding direction by the primary guide means.

The intermediate frame provides space for secondary drive means in the form of a linear actuator 22 which is placed centrally therein. Actuator 22 is connected at a first side to intermediate frame 20 and is coupled at an opposite end to a lift platform 30. For weight saving considerations the lift platform is manufactured almost completely of aluminium. Stainless steel is mainly used for the other parts of the device.

Lift platform 30 extends displaceably from intermediate frame 20 and is received movably with guide rollers 31 by linear secondary guide means 23 on an inner side of the outer profiles of intermediate frame 20. Just as the intermediate frame, the lift platform also lies in its guide 23 in freely pivotable manner about a pivot shaft directed transversely of a direction of displacement thereof. Both intermediate frame 20 and lift platform 30 are thus continuously able to take up an optimal stable position which takes into account an actual angle of inclination, hi the extreme position shown in figure IA lift platform 30 thus lies substantially flat on a ground surface. Lift platform 30 herein supports in rolling manner on the ground surface at a free outer end with rollers 32 and bridges a remaining height with a bridge part 33 mounted tiltably on the outer end. The lift platform comprises on either side an upright part 34 which is about 10 cm high and from an upper side of which a substantially flat elongate support part 35 extends in transverse direction. This support part 35 serves as footboard for facilitating getting in and out of an invalid vehicle (not shown) placed on lift platform 30. Upright part 34 encloses the carriage laterally, while an adjustable bar 36 just behind the invalid vehicle fixes the vehicle in longitudinal direction on the lift platform.

In order to carry an object into a vehicle it is first placed on the lift platform. In the case of an invalid vehicle, this is for instance moved onto the platform, optionally using the motor, to a position over the adjustable bar 36. Bridge part 33 is then closed and locked with a protrusion 37 provided for this purpose. Linear actuator 22 is now energized to carry the lift platform from the extended position lying at least substantially wholly outside base frame 10 as shown in figure IA, via the secondary guide means 23 and a secondary path imposed thereby inside intermediate frame 20. Lift platform 30 is eventually situated wholly within the intermediate frame, as shown as intermediate position in figure IB.

In order to carry intermediate frame 20 with lift platform 30 from the intermediate position shown in figure IB to the position shown in figure 1 C located at least substantially fully within base frame 10, the primary drive means in the form of winch 11 are energized. When the winch cable is tightened, intermediate frame 20 will thus be pulled inside base frame 10 and herein be forced into a primary path imposed by the primary guide means 16,17 along guide rails 17 until intermediate frame 20 lies at least substantially wholly within the base frame, see figure 1C. Within this primary path the intermediate frame 20 tilts over guide rollers 16 on an edge of the base frame so that it finally lies substantially flat on a bottom of the base frame.

In this final position the tensioning spring 17 will be fully tensioned. The tensioning spring thus exerts a bias on intermediate frame 20 which is sufficient, when the winch tension is released, to force intermediate frame 20 out of base frame 10. An outward movement in opposite direction can thus be initiated, which is followed by energizing of actuator 22 for the purpose of carrying lift platform 30 outside the intermediate frame. A PLC control device (not shown) controls both cycles, actuated for this purpose by a wireless hand control device which can be operated by a user. In order to compensate for a height difference in the ground surface, in particular a raised surface such as a pavement, the control device comprises end-point detectors, for instance in the form of touch-sensitive sensors, arranged on a bottom side at an outer end of the intermediate frame and/or the lift platform. When actuated, these detectors generate an electronic signal to a central control unit which interrupts an outward movement of the intermediate frame or lift platform. In addition, the control unit comprises touch- sensitive safety sensors (not shown) on a front side of the intermediate frame and/or lift platform, for instance in the form of a link strip, for the purpose of generating an electronic signal to the control unit when a predetermined resistance is exceeded in order to interrupt an inward movement of the intermediate frame or the lift platform.

A second exemplary embodiment of a lifting device according to the invention is shown in figure 2. This embodiment is wholly similar to the first, except that the primary drive means in this case comprise a pair of linear actuators 18 arranged in base frame 10. These actuators 18 replace winch 11,13 with winch cable 12 and pulleys 14 as well as tensioning spring 50. A greatly simplified construction is thus obtained which functions in wholly similar manner to the above described embodiment, except that the primary drive means can now produce both a pulling force and a pushing force.

Although the invention has been further elucidated on the basis of only two exemplary embodiments, it will be apparent that the invention is by no means limited thereto. On the contrary, many more variations and embodiments are possible for the person with ordinary skill in the art within the scope of the invention. The lifting device can thus also be applied without base frame, wherein the primary drive means and guide are mounted directly inside an accommodating vehicle, with the consequence of a longer installation time. The stated drive means, materials and dimensions, although particularly suitable within the scope of the invention, can also be replaced by others.

Claims

1. Lifting device for a vehicle, comprising a lift platform intended and adapted to receive an object for lifting, and a drive device for displacing the lift platform in

S energized manner between a retracted position located at least substantially inside the vehicle and an extended position located at least substantially outside the vehicle, wherein there is a height difference between the retracted position and the extended position, characterized in that the lift platform extends displaceably from a displaceable intermediate frame which is tiltable relative to an edge of the vehicle, 0 that primary guide means are provided which are intended and adapted to be received in the vehicle and which impose a primary path on the intermediate frame, that the drive device comprises primary drive means for the purpose of displacing the intermediate frame in co-action with the primary guide means in the primary path between a retracted position lying at least substantially inside the vehicle and an 5 extended position lying at least substantially outside the vehicle, that the intermediate frame comprises secondary guide means which movably receive at least an outer end of the lift platform and impose a secondary path, and that the drive device comprises secondary drive means for the purpose of displacing the lift platform in co-action with the secondary guide means in the secondary path between a retracted position lying at0 least substantially inside the intermediate frame and an extended position lying at least substantially outside the intermediate frame.

2. Lifting device as claimed in claim 1, characterized in that the intermediate frame co-acts with the primary guide means for pivoting about a pivot shaft directed5 transversely of the primary path, and that said outer end of the lift platform co-acts with the second guide means for pivoting about a pivot shaft directed transversely of the second path.

3. Lifting device as claimed in claim 1 or 2, characterized in that the primary drive0 means comprise at least one linear actuator which can be attached optionally directly to the vehicle at a first outer end and is coupled to the intermediate frame at an opposite outer end.

4. Lifting device as claimed in claim 1 or 2, characterized in that the primary drive means comprise at least one driven winch which is intended and adapted to be connected firmly to the vehicle in optionally direct manner, and from which extends a cable, a free end of which is coupled to the intermediate frame.

5. Lifting device as claimed in claim 4, characterized in that the primary drive means comprise a tensioning spring coupled to the winch cable for the purpose of applying a bias during winding-up of the at least one winch, this bias being sufficient to displace the intermediate frame in an opposite direction when a winch tension falls away.

6. Lifting device as claimed in one or more of the foregoing claims, characterized in that the primary guide means comprise guide rails over which guide members run at least substantially fittingly on at least both sides, which guide rails and guide members can be firmly attached on either side of the intermediate frame to the vehicle for reciprocation at a height above a vehicle floor and/or are connected to the intermediate frame.

7. Lifting device as claimed in claim 6, characterized in that the guide rails comprise tubular profiles over which the guide members roll in at least substantially fitting manner on both sides with a concave guide surface adapted thereto.

8. Lifting device as claimed in claim 6 or 7, characterized in that the guide rails and the guide members are manufactured at least substantially from steel.

9. Lifting device as claimed in one or more of the foregoing claims, characterized in that the intermediate frame, at least in the extended position thereof, is pivotable inside the primary guide at the first outer end and is able and adapted to support on a ground surface at the second outer end.

10. Lifting device as claimed in one or more of the foregoing claims, characterized in that the primary guide means extend from a base frame which moreover at least substantially comprises the primary drive means, which base frame can be fixed to a vehicle floor.

11. Lifting device as claimed in one or more of the foregoing claims, characterized in that the intermediate frame comprises the secondary drive means.

12. Lifting device as claimed in one or more of the foregoing claims, characterized in that the secondary drive means comprise at least one linear actuator arranged between the intermediate frame and the lift platform.

13. Lifting device as claimed in one or more of the foregoing claims, characterized in that the lift platform, at least in the extended position thereof, is mounted at the first outer end for pivoting relative to the intermediate frame and at an opposite free outer end is able and adapted to support on a ground surface.

14. Lifting device as claimed in one or more of the foregoing claims, characterized in that the lift platform is provided on an underside of a free outer end with rolling means for rolling support on a ground surface therewith.

15. Lifting device as claimed in one or more of the foregoing claims, characterized in that the lift platform is provided on a carrying side with an adjustable bar.

16. Lifting device as claimed in one or more of the foregoing claims, characterized in that on opposite longitudinal sides the lift platform comprises an upright part with an at least substantially flat elongate support part extending therefrom in a transverse direction.

17. Lifting device as claimed in one or more of the foregoing claims, characterized in that the lift platform comprises at a free outer end a tillable bridge part which is pivotally connected thereto and which in a folded-out position bridges a remaining height above a ground surface and which in a folded-in position closes the lift platform.

18. Lifting device as claimed in one or more of the foregoing claims, characterized in that the lift platform is manufactured at least substantially of aluminium and that the lifting device otherwise comprises at least substantially parts of stainless steel.

19. Lifting device as claimed in one or more of the foregoing claims, characterized in that a control device is provided which in a first mode controls the primary and secondary drive means successively in an outward movement and in a second mode impose an inward movement on successively the secondary and primary drive means.

20. Lifting device as claimed in claim 19, characterized in that the control device comprises at least one touch-sensitive end sensor which is arranged close to a free outer end on an underside of the intermediate frame and which, when actuated, generates an electronic signal, upon which the control device interrupts the outward movement.

21. Lifting device as claimed in claim 19 or 20, characterized in that the control device comprises at least one touch-sensitive end sensor which is arranged close to a free outer end on an underside of the lift platform and which, when actuated, generates an electronic signal, upon which the control device shuts off the outward movement.

22. Lifting device as claimed in claim 19, 20 or 21 , characterized in that the control device comprises at least one touch-sensitive safety sensor which is arranged on a front side of the lift platform and/or on a front side of the intermediate frame and which, when actuated, generates an electronic signal, upon which the control device interrupts the inward movement.