Field of the invention The present invention relates to a lifting device according to the preamble of the appended claim 1 .

Background of the invention Barrier-free movement has recently attracted increasing attention, so that moving from one place to another would be easier to disabled people, too. For example when moving with a wheelchair, even a relatively low doorstep may cause difficulties. One solution is to provide a stairway with a slanted ramp having an even surface. Due to the slope of the ramp, moving with a wheelchair may still be difficult, because moving upwards will require a greater force than moving in the horizontal direction, and correspondingly when moving downwards along such a slanted surface, the movement of the wheelchair has to be slowed down by braking. A ramp of prior art, aiming at eliminating the above mentioned drawback, is disclosed in patent US 3,341 ,874. This solution comprises a platform (a hoist bridge) connected at its first end in an articulated way to an upper step level or the like, the second end of the platform being arranged between pillars so that this second end of the platform can be hoisted and lowered. The plat- form is further divided into two portions in the longitudinal direction, whereby the rear second portion of the platform is slightly less inclined than the first portion when the platform is in its lower position. Hoisting and lowering the platform is powered by a motor which is in a power transmission connection by a cable to the second end of the platform. The other end of the cable is connected to the top of a pillar on the other side of the platform. In this way, the rotating motion of the motor causes the cable to be taken in on a hoisting pulley when the platform is being hoisted, and to be rolled out from the pulley when the platform is being lowered, respectively. Further, a deck is provided at one end of the platform, which deck can be lifted to an upright position when the wheelchair is being hoisted or lowered on the platform. The function of the deck is to prevent the wheelchair from sliding off the platform. One drawback in this solution is the fact that the platform is not always in a substantially horizontal position during hoisting and lowering, in spite of the two- part structure of the platform, but it is always inclined to some extent, particularly when the platform is in the lower position. This means that during hoist- ing and lowering, the wheelchair is subjected to a force moving the wheelchair towards the rear end of the platform. Therefore, the wheelchair has to be fastened very carefully for the time of the hoisting and lowering.

Brief summary of the invention

It is an aim of the present invention to improve the state of art and to provide a lifting device by which the above mentioned drawbacks are avoided to at least some extent. The lifting device according to the present invention is primarily characterized in what will be presented in the characterizing part of the appended claim 1 .

Significant advantages can be achieved with the lifting device according to the present invention. When using the lifting device according to the invention, the platform remains in a substantially horizontal position during the whole operation of lifting and lowering, whereby the wheelchair also remains in a substantially horizontal position during the whole operation of lifting and lowering, which reduces forces effective on the load and substantially deviating from the vertical direction. In other words, the wheelchair, or the like, to be lifted/lowered is not subjected to such significant forces which could make it difficult for the load/person to remain on the platform of the lifting device.

Description of the drawings

In the following, the present invention will be described in more detail with reference to the appended drawings, in which

Fig. 1 shows a lifting device according to an advantageous embodiment of the invention, in a reduced perspective view; Fig. 2 shows a detail of the lifting device according to Fig. 1 , without the platform; Fig. 3 shows the lifting mechanism of a so-called kickplate of a lifting device according to an advantageous embodiment of the invention, in a reduced view;

Fig. 4 shows the lifting mechanism for a safety guard in a lifting device according to an advantageous embodiment of the invention, in a reduced view; shows a detail of the lifting mechanism of a lifting device according to an advantageous embodiment of the invention, in a first position; shows a detail of the lifting mechanism of a lifting device according to an advantageous embodiment of the invention, in a second position; shows a detail of the lifting device of Fig. 2, in a perspective view from another direction; shows the lifting mechanism for a safety guard in a lifting device according to an advantageous embodiment of the invention, in a reduced perspective view; shows a detail of the lifting mechanism of the platform in a lifting device according to an advantageous embodiment of the invention, in a reduced perspective view; and

Figs. 9a to 9d show a guide in a lifting device according to an advantageo embodiment of the invention.

Detailed description of the invention Figure 1 shows a lifting device 21 according to an advantageous embodiment of the invention in a reduced perspective view. The lifting device 21 compris- es e.g. a hoisting platform 4, a ramp 5 for the hoisting platform, a safety rail 6, and possibly one or more kickplates 7 as well. In the embodiment of Fig. 1 , three kickplates 7 are provided. The lifting device 21 also comprises a hydraulic cylinder 8 or a corresponding actuating member, as well as a mechanism 9 for lifting the hoisting platform, whereby the force generated by the hydraulic cylinder 8 can be converted to a movement elevating/lowering the hoisting platform. The lifting device 21 according to an example of the invention further comprises a lifting mechanism 13 for the safety rail 6, whereby the safety rail 6 is also moved when the hoisting platform 4 is moved. The lifting mechanism 9 for the hoisting platform and the lifting mechanism 13 for the safety rail will be described in more detail further below in this description.

In Fig. 1 , the lifting device 21 according to a preferred embodiment of the invention is arranged in connection with a door 2 in a wall 1 of a building, on the side of a floor 3. The wall 1 may be the outer wall of the building, or a wall connecting two different rooms. There is a height difference between these spaces, so that the lifting device 21 is used to facilitate moving between these two different spaces in a way to be described below in this description. The floor 3, or the space outside the wall, may also be outdoors, such as a pavement. In other words, the hoisting platform 4 of the lifting device 21 is arranged for elevating and lowering a person between two different height positions. Figure 2 shows the operating principle and functional components of the lifting device according to a preferred embodiment of the invention. A hydraulic cylinder 8 is used for moving a force coupling board 20 up or down according to whether the hoisting platform 4 is to be lifted or lowered. For lifting the hoisting platform 4 up, the piston of the hydraulic cylinder 8 is thrust outwards from the hydraulic cylinder 8, whereby the force coupling board 20 moves upward. The force coupling board 20 is connected at both ends to the lifting mechanism 9 of the hoisting platform. Thus, the force coupling board 20 also lifts the horizontal beams 9a of the lifting mechanism 9. Both ends of the horizontal beams 9a are provided with push rods 9b, the hoisting platform 4 being supported to their top end. Thus, when the horizontal beams 9a move upward, the push rods 9b move upward as well and lift the hoisting platform 4. In a corresponding way, for lowering the hoisting platform 4 down, the piston of the hydraulic cylinder 8 is withdrawn into the hydraulic cylinder 8, whereby the force coupling board 20, the horizontal beams 9a, the push rods 9b, and the hoisting platform 4 move downward.

Guide tracks 12 are used, among other things, to keep the movement of the hoisting platform 4 as smooth as possible so that the hoisting platform 4 remains in a substantially horizontal position when it is being lifted up or lowered down. Preferably, two such guide tracks 12 for the hoisting platform are provided, but it is also possible to have only one guide track or more than two guide tracks. In connection with the hoisting platform 4, a guide plate 12a is provided whose one end is preferably shaped to keep the guide plate inside the cross-sectional profile of the guide track 12. The cross-sectional profile of the guide track 12 is preferably a rectangle with a gap on one side. This gap allows the movement of the guide plate 12a inside the guide track 12.

A mechanism 10 for lifting kickplates is provided in connection with the lifting mechanism 9 of the hoisting platform, one example being shown in Fig. 3. The mechanism 10 for lifting kickplates comprises, for example, a first rod 14, a second rod 16, and a connecting rod 15 therebetween. One end of the first rod 14 is preferably rigidly mounted to the lifting mechanism 9 of the hoisting platform so that when the lifting mechanism of the hoisting platform moves, the first rod 14 will move as well. The first rod 14 is preferably mounted on the pivot of the two-part push rod 9b for example in such a way that the angle between the first rod 14 and the lower push rod remains substantially constant. One end of the connecting rod 15 is connected to the second end of the first rod 14, and the other end of the connecting rod 15 is connected to the first end of the second rod 16. The second end of the second rod 16 is connected to the kickplate 7, for example by a kind of a shaft journal 16a. The movement of the first rod 14 generates a movement of the connecting rod 15 and the second rod 16, whereby the kickplates 7 are also moved respectively. In other words, the mechanism 10 for lifting the kickplates, as presented above, generates the movement of the kickplates 7 in a substantially vertical direction while the hoisting platform 4 is moved up or down. Consequently, no separate hoisting apparatus will be needed. The kickplates 7 lifted in the upper position form a wall extending higher than the edges of the hoisting platform 4, reducing the risk that a person placed on the hoisting platform might fall off the hoisting platform. In other words, the upper edge of the kickplate 7 is configured to be flush with the upper surface of the hoisting platform when the hoisting platform 4 is placed in the lower position (of two different height positions). In a corresponding way, the upper edge of the kickplate 7 is configured to be higher than the upper surface of the hoisting platform when the hoisting platform 4 is placed in the upper position (of two different height positions).

In this context, it should be mentioned that a kickplate 7 is not necessarily provided at that edge of the hoisting platform 4, from which the person can move off the hoisting platform 4, when the hoisting platform 4 has been lifted to the upper position. For instance in the example of Fig. 1 , this edge of the hoisting platform 4 is the edge on the side of the door 2. On the other hand, this edge may be equipped with a kind of a ramp to cover a possible gap left between the upper surface of the hoisting platform 4 and the doorstep or another exiting surface level, when the hoisting platform 4 is in the upper position, that is, substantially flush with the doorstep or other exiting surface level. In Fig. 1 , the hoisting platform 4 is in this upper position.

Figure 4 shows a lifting mechanism 22 for a safety guard 6 connected to the lifting mechanism 9 of the hoisting platform 4. The lifting mechanism 22 for the safety guard advantageously comprises a vertical beam 1 1 which prefer- ably has a cross-sectional profile resembling the letter C or a rectangle with a gap on one side. Such a beam may also be called a C beam. The upper end of the vertical beam 1 1 is equipped with a lever 18 whose one end is connected to the vertical beam 1 1 and other end to the safety guard 6 by a fixing mechanism comprising e.g. a guide piece 17. The guide piece 17 is mounted on the safety guard 6 close to the first end 6a of the safety guard. The first end 6a of the safety guard 6 is connected to a guide support 19 mounted on the frame structure.

Figure 5a shows a detail of the lifting mechanism of the lifting device accord- ing to a preferred embodiment of the invention in a first position, and Fig. 5b shows a detail of the lifting mechanism of the lifting device according to a preferred embodiment of the invention in a second position. In this example, the first position refers to the position in which the hoisting platform 4 is lowered down, and the second position, respectively, refers to the position in which the hoisting platform 4 is lifted up. In Figs. 5a and 5b, the same parts are referred to by the same reference numerals as in connection with Figs. 1 to 4.

Figure 6 shows a detail of the lifting device of Fig. 2 in a perspective view from another direction.

Figure 7 shows the lifting mechanism 13 for a safety guard in a lifting device according to an advantageous embodiment of the invention in a reduced perspective view. This corresponds substantially to the lifting mechanism 13 for a safety guard as shown in Fig. 4 as well. This lifting mechanism 13 for a safety guard preferably operates in the following way. When the hoisting platform 4 is elevated, it lifts the vertical beam 1 1 upwards. The guide support 19 is not moved with the hoisting platform 4, so that the first end 6a of the safety guard 6 is not moved in the vertical position either. The lever 18 belonging to the lifting mechanism 13 for the safety guard pushes the guide piece 17 upwards, causing the second end of the safety guard 6 to move upwards. Preferably, the safety guard 6 is substantially in the horizontal position when the hoisting platform 4 is in the upper position. Correspondingly, when the hoisting platform 4 descends, it lowers the vertical beam 1 1 downwards. Now, the lever 18 belonging to the lifting mechanism 13 for the safety guard pulls the guide piece 17 downwards, causing the second end of the safety guard 6 to move downwards. Preferably, when the hoisting platform 4 is in the lower position, the safety guard 6 is substantially in the vertical position in such a way that the second end of the safety guard 6 is down, close to the surface of the hoisting platform 4. Thus, the safety guard 6 is preferably at least partly inside the C profile of the vertical beam 1 1 and does not significantly hamper movement in the vicinity of the lifting device.

Figure 8 shows a detail of a lifting device 21 according to a preferred embodiment of the invention in a reduced perspective view, and Figs. 9a to 9d show a guide 12c in a lifting device according to a preferred embodiment of the invention. In this embodiment, the guide 12c and another, auxiliary guide track 12b, connected to the guide, are configured to be movable in the guide track 12. The auxiliary guide track 12b is fastened to the kickplate 7 in such a way that the kickplate 7 is movable in the gap left between the auxiliary guide track 12b and the guide track 12. Thus, both vertical surfaces of the kickplate 7 are supported to keep the kickplate 7 in a substantially vertical position when the hoisting platform 4 is lifted and lowered. One end of the guide 12c is provided with a hole 12e to receive a shaft (not shown) that connects rollers 12d. Thus the rollers 12d, placed on both sides of the guide 12c, can roll when the hoisting platform 4 is lifted or lowered. The purpose of this arrangement is to prevent the formation of a substantial gap between the kickplate 7 and the hoisting platform 4, in which gap various trash, such as tree leaves, could accumulate. Moreover, a possible gap could, particularly in a hoisting situation, cause a danger situation if e.g. a wheel of a wheelchair or a walker-rollator were stuck in the gap.

Heating can be provided in the relevant parts of the lifting device according to the invention, if necessary. Moreover, the lifting height of the hoisting platform 4 from the street/floor level may be adjustable, for example by adjusting the piston stroke of the hydraulic cylinder and by changing the length of the lifting bars of the lifting mechanism of the hoisting platform. The lifting mechanism 13 for the safety guard may be enclosed, as may the lower end of the guide support 19, to prevent a risk of compression.

Further, if necessary, a water trough, or the like, can be installed in connec- tion with the lifting device according to the invention, for conveying possible melt water and rainwater into a drainage at the site of installation of the lifting device, or away from the foundation of the building.

It should be mentioned that although only the wheelchair has been men- tioned above as a vehicle facilitating movement, the lifting device according to the present invention facilitates the movement of people who use other vehicles equipped with wheels as well. An example of such a vehicle is a so- called walker-rollator which is used as a kind of support when a person using the walker-rollator is moving on his/her own feet. It is obvious that instead of or in addition to the hydraulic cylinder 8, another power device can be used as well, such as a motor equipped with a transmission mechanism for elevating and lowering the hoisting platform 4 as needed.

The present invention is not limited solely to the above-presented embodiments but it can be modified within the scope of the appended claims.