The known lift device comprises two parallel swivel arms, one on each roll-on/off side of the platform. On one side of the platform a vertical wall part is arranged parallel to the direction of irement. On both sides of the wall part a swivel arm is mounted on a pivot. The pivots are arranged in line, parallel to the normal direction of movement of the wheelchair on the platform. Each swivel arm has a first part which extends at right angles to the direction of movement > in the second position and a second part which extends parallel to the direction of movement. The two second parts are in line and directed towards each other.

In the swung-up first position, the first parts extend vertically, the second parts horizontally.

This known lift device has a number of drawbacks, in particular during use by a wheelchair user. During manipulation of the swivel arm between the first and the second position, the free ends of the second parts move relatively far above the platform. With conventional dimensions of the known platform, the second parts are located, e.g., about 1.6 m above it. This means that with conventional dimensions of e.g. stairways in offices and dwelling-houses the platform cannot be used with the swivel

arms in the first position. In addition, this involves that the swivel arms move out of reach of a sitting adult.

Consequently, a wheelchair user will first have to proceed with his wheelchair onto the platform before he can operate the swivel arms by seizing the first part. Furthermore, during use a wheelchair user must always operate at least one of the swivel arms behind himself, which is often not possible, at least only with excessive efforts. Furthermore, a swivel arm of the known lift device cannot be reached or operated from a story floor.

The invention relates to a lift device of the present type in which the above drawbacks are avoided while retaining the advantages thereof. To this end, a lift device according to the invention is characterized by the features according to the characterizing part of the main claim.

The inclined position of the swivel axis relative to the direction of movement of the platform limits the envelope of movement of the swivel arm, i.e. the space in which the swivel arm moves between the first and the second position, and vice versa, while the swivel arm can freely pass over an adult sitting in a wheelchair on the platform. One swivel arm can be reached and seized from both sides of the platform during the complete movement of the swivel arm between the first and the second position. Moreover, in the second position, both on the side of the platform and on the so- called "high" side, i.e. the side of the platform where the distance between the stairway plane and the platform is

largest, the swivel arm provides sufficient protection against the wheelchair rolling off the platform. A further important advantage of a lift device according to the invention is that in the swung-up first position the swivel arm has a relatively small height above the platform, while, moreover, the highest point of this swivel arm is located relatively far within the contour of the platform, seen in top plan view, at least near a center line thereof located transversely to the direction of movement, in a manner such that the lift device can be moved along the stairway plane both with the swivel arm in the first position and with the swivel arm in the second position without touching, e.g., a story floor or a superjacent stairway, or the like.

Consequently, when moving up the empty lift device, the user need not swing up the swivel arm.

The lift device according to the invention requires relatively little space and is very ergonomic in use, while, moreover, the safety requirements imposed on such lift devices are satisfied in a suitable manner.

In a further elaboration, a lift device according to the invention is further characterized by the features of claim 2.

When using a lift device in such an embodiment, the advantage obtained for the user is that he can always simply and independently operate and control by hand the swivel arm and the movements thereof, irrespective of the position of the wheelchair on the platform. This only requires operation

of a swivel arm. The design of a swivel arm according to the invention and the arrangement of the pivot offer the advantage that the swivel arm can simply move over the head of an adult of normal stature sitting in a wheelchair and can be controlled, in principle over the complete path of movement of the platform.

In a preferred embodiment a lift device according to the invention is further characterized by the features of claim 3.

A bent embodiment of a swivel arm of a lift device according to the invention offers the advantage that during movement between the first and the second position, and vice versa, this embodiment provides much space within the envelope of movement while the free end of the swivel arm can move along a relatively small, low-lying path of movement. A substantially two-part embodiment of the swivel arm, which two parts are of convex construction, seen from the platform, provides an optimum ratio between the space within the swivel arm on the platform and the dimensions of the lift device, in particular when the swivel arm is in the first, swung-up position. Of course, the swivel arm may also be shaped differently with at least substantially the same effect.

The swivel arm may extend at least partially along three of the sides of the platform, at least surround a wheelchair placed thereon, but in a very advantageous embodiment a lift device according to the invention is characterized by the features of claim 6.

The fact that the swivel arm leaves a roll-on/off side of the platform clear offers the advantage that the swivel arm need not always be swung up when a wheelchair is to be rolled on or off the platform.

A swivel arm assembly for use in a lift device according to the claim can be of simple construction so as to be universally applicable, i.e. such a swivel arm assembly can be arranged both on the left-hand side and on the right- hand side of the longitudinal wall.

Further advantageous embodiments of a lift device according to the invention and a swivel arm assembly for use in a lift device according to the invention are given in the subclaims.

In explanation of the invention, practical examples of a lift device and a swivel arm assembly for this lift device will be described with reference to the accompanying drawings in which: Fig. 1 is a top plan view of an assembly of a platform and a swivel arm according to the invention, with the swivel arm swung down; Fig. 2 is front view of an assembly of Fig. 1; Fig. 3 is a side view of an assembly of Fig. 1, with the swivel arm swung up; Fig. 3A is a side view of an assembly of Fig. 3, with the swivel arm swung down and a wheelchair placed on the platform; and

Fig. 4 is a top plan view of an alternative embodiment of an assembly of a platform and a swivel arm, with the swivel arm swung down.

In this description of the drawings, similar or comparable parts will be indicated by the same reference numerals, if required increased by 100.

Figs. 1-3 show a first embodiment of a lift device 1 with a swivel arm 9 according to the invention. The lift device 1 comprises a platform 2 which is joined via two hinge means 3 to a vertical longitudinal wall 4 arranged on a longitudinal side thereof. Thus, the platform 2 can be swung up against the longitudinal wall 4 to enable minimization of the storage space and to clear the stairway plane. Hinged to each of the end sections 5 of the platform 2, which extend at right angles to the above longitudinal wall, is a roll-on/off plate 6. These roll-on/off plates 6 can be swung up in the direction of the platform 2 until they include an angle of, e.g., 1350 to the platform 2. The purpose thereof will be explained lower down. Provided on a first side 7 of the longitudinal wall 4 near the upper end thereof is a pivot 8, which will be described lower down. Connected to the pivot 8 is a swivel arm 9, which is composed of two bent parts 10, 11. The first bent part 10 has a length L1, which approximately corresponds to the width of the platform 2, and the second part 11 has a length L2, which is approximately equal to, or slightly shorter or longer than, the length of the platform 2. The first part 10 and the second part 11 are

connected together in a connecting point 12 while including an angle such that the chord of the first part 10, seen in top plan view and with the swivel arm 9 swung down (Fig. 1), is approximately parallel to an end section 5 of the platform, while the chord of the second part 11 extends approximately parallel to the longitudinal edge of the platform 2 remote from the longitudinal wall 4. The platform 2 has such dimensions that a wheelchair of conventional dimensions can be simply placed thereon.

The pivot 8 includes, seen in top plan view (Fig. 1), a first angle a to the longitudinal direction of the platform 2. By way of illustration, Fig. 1 of the drawings shows, in top plan view, a center line N of the platform 2, which corresponds to the normal direction of movement of a wheelchair when rolling on and off the platform. Seen in side view (Fig. 3), the pivot 8 includes a second angle , the angle between the longitudinal axis of the pivot 8 and the horizontal H. As a result of this so-called double-inclined position of the pivot 8, the bend 12 of the swivel arm 9 while passing from the swung-down position, as shown in Figs. 1 and 2, to the swung-up position, as shown in Fig. 3, does not move parallel to the end sections 5 but moves to above the longitudinal wall 4. In other words, this bend 12 moves, seen in side view (Fig. 3), along a path of movement which includes an angle to the vertical, such that the bend 12 moves from the swung-down position, as shown in Fig. 1, in the direction of the center line M of the platform 2, over a

distance D. This also means that in the swung-up position of the swivel arm 9 the bend 12, as shown in Fig. 3, comes out a distance E less high than when the pivot 8 would extend horizontally, as shown in Fig. 3 in broken lines. Moreover, when a pivot 8 is in the horizontal position, the second part 11 would extend above the bend 12, so that the total height of such a lift device with the swivel arm in the swung-up position would increase even more. Fig. 3 is a diagrammatic representation of two conventional story floors located above the stairway plane over which the lift device 1 has to move.

The lines designated as respectively 300 and 70" show the inclination of a rail for the lift device. These lines 30°, 700 indicate the lines of contact, at the relevant angle of inclination, to an edge of a superjacent story floor. As is apparent from Fig. 3, a lift device 1 with the swivel arm 9 swung up can simply pass such a story floor. This means that the lift device 1, both with the arm 9 swung up and with the arm 9 swung down, can be moved between the stairway plane and the superjacent story floor. In the practical examples shown, the angles a and of the pivot 8 are so chosen that the pivot inclines upwards and in the direction remote from the platform 2. This angle of inclination may be chosen as desired. If desired, one of the angles a, may actually be very small. It is preferred, however, that the pivot 8 is clearly inclined in two directions, e.g. with a and being between 10° and 200.

Arranged between the longitudinal wall 4 and the swivel arm 9, at least the pivot 8 therefor, is a telescopic spring 13 or a torsion spring or such a spring and balancing means which simplifies swivelling up and down of the swivel arm 9, and which brakes, at least damps, the movements thereof.

Consequently, the operation of the swivel arm 9 is simple.

An additional advantage of the double-bent swivel arm 9 is that the free end 14 of the second part 11 of the swivel arm 9 moves up over a relatively small distance relative to the swung-down position. This means that this free end 14 remains within reach of an adult sitting in a wheelchair +placed on the platform 2 or on a story floor 15 connecting to the end section 5 shown on the right-hand side of Fig. 3.

the swivel arm 9 in particular. When a wheelchair is rolled forward from the story floor 15 onto the platform 2, it can also pass between the longitudinal wall 4 and the free end 14 of the swivel arm 9 when the swivel arm is swung down.

In the position placed on the platform 2, a user is protected on at least the high side 16 of the platform 2 and the long sides of the platform 2 by respectively the first part 10, the second part 11 and the longitudinal wall 4. When the lift device arrives on a subjacent story floor, the swivel arm 9 can be simply brought into the swung-up position, by seizing the first part 10 thereof. Should a user be positioned with his face towards the free end 14 of the swivel arm 9, then the swivel arm 9 can be simply brought into the swung-up position by seizing the second part 11, e.g. at the free end

14. As a result of the double-bent configuration, the swivel arm 9 can be simply moved over the head of the sitting adult without the risk of the swivel arm coming into contact with the user. Consequently, the ease of use of a lift device 1 according to the invention is increased even further.

Moreover, the swivel arm 9 offers the advantage that it forms a roll-off protection for the wheelchair in case of an inclined position of the platform 2, e.g. in case of fracture in parts of the lift device. The handles of the wheelchair then engage over the swivel arm 9 and thus prevent the wheelchair from slipping under the swivel arm 9. In the swung-up position, the roll-on/off plates 6 include an angle of, e.g., about 1350 to the platform 2 and form a stop to the wheels of the wheelchair, by way of a further roll-off protection. Since the first part 10 of the swivel arm 9 is bent outwardly, it can extra simply pass the handles of the wheelchair during swivelling.

Fig. 4 shows an alternative embodiment of a lift device 101 in which the swivel arm 109 comprises a one-part double- bent first part 110 and a bent second part 111 swivel-mounted thereon. The swivel axis Z of the second part 111 is located such that when the second part 111 is swung up, it can be moved against the first part 110, while, e.g., spring means may be provided for fixing the second part 111 in these two positions. Such a second part 111 may offer the advantage that the swivel arm 109 offers protection on three sides of the platform 102, while the swivel arm 109 can be simply

brought into the swung-up position. The second part again forms a roll-off protection. Moreover, this makes it even more simple to seize the swivel arm on that side.

A lift device 1, 101 according to the invention is very suitable for use as a stairway lift in which conventional means are provided for moving the lift device along the stairway plane, such as guide rails, guide wheels, drive means, and the like. Operating means for the lift device may be provided in the conventional manner, e.g. on the longitudinal wall 4, 104 or near the ends of the stairway.

These and comparable embodiments and applications are considered to be within reach of those skilled in the art.

The invention is by no means limited to the embodiments shown and described in the figures and the specification.

Many variations are possible.

Thus, the swivel arm may be bent in different ways, and it may be composed of any desired number of straight or bent parts. The angles a and enclosed by the pivot 8, 108 may be suitably selected according to the available height for the lift device below a superjacent story floor. The pivot 8, 108 for the swivel arm 9, 109 may be mounted on each of the sides of the longitudinal wall 104, thus making the lift device suitable for any type of stairway.

Of course, the further lift device may be formed in different other ways, e.g. with a fixed platform or with an open longitudinal wall. These and many comparable embodiments are considered to fall within the scope of the invention.