Technical Background of the Invention An elevator device of the kind defined above is of- ten used to allow disabled persons to reach e. g. elevated entrances and to bypass stairways.

Elevator devices of this kind comprises a plurality of mutually movable parts arranged to provide safe and convenient transportation. For instance, they often in- clude a load-carrying platform, which is arranged to be lifted vertically when affected by a power unit, such as a motor. Often, the load-carrying platform is arranged to slide or be displaced in a horizontal plane in order to reach the top of the stairway or the like following the lifting operation. Likewise, such movements often are ef- fected by means of a separate power unit. In order to avoid that the platform obstructs the entrance, it is of- ten arranged to pivot about a vertical axis. While being hoisted from a basic position at ground level to an unloading position, the platform is suitably pivoted over a quarter of a full turn. This pivotal movement usually is effected by means of an additional separate power

unit, which serves to effect this movement of the eleva- tor device.

In order to enable all three displacement movements, the elevator structures often become heavy, since every motor adds weight to the structure, in addition to which each motor needs a strong frame to which it may be at- tached, which adds further weight to the elevator struc- ture.

Summary of the Invention The main object of the present invention therefore is to suggest an elevator device, which is capable of ef- fecting the above displacement movements by means of one common power unit. Another object of the invention thus made possible is a reduction of the weight of the eleva- tor device in order among other things to simplify the mounting work involved in installing the elevator.

These objects have been achieved according to the teachings of the invention by means of an elevator device possessing the characteristics defined in the appended claim 1. Preferred embodiments of the invention appear from the appended dependent claims.

The invention thus concerns an elevator device com- prising a support structure and at least one laterally fixed column equipped with a hoistable load carrier, which is mounted for pivotal movement about the column, and with a lifting unit and a power unit, said units preferably mounted on the support structure to allow dis- placement of the load carrier vertically along the col- umn, said device being characterised by the provision of a follower and a guide, said follower and guide being ar- ranged to engage one another in a groove in a point of contact located between the load carrier and the support

structure, either the guide or the follower arranged to be fixed relative to the pivotal plane of the load car- rier, thus causing a relative motion between the load carrier and the column, whereby the load carrier is forced to pivot about the column while being displaced vertically.

The advantages gained by this arrangement are that it allows the structure of the elevator device to be more light-weight, since only one power unit is required both to effect the pivotal movement about a vertical axis and to provide the power to lift the load carrier. This obvi- ously is a considerable advantage, since several struc- tural members may be made less heavy compared with ear- lier structures, thus simplifying the mounting of the elevator device and making it easier. Owing to the less pressing need for more than one power unit, which is an expensive component of modern elevators, it becomes pos- sible to reduce the manufacturing costs.

The follower preferably is arranged to be raised and lowered and to pivot about the column. The load carrier is associated with the follower. Consequently, in a con- venient manner the guide may be placed in engagement with the previously mentioned groove in the follower, at a suitable level relative to the curvature of said groove, in order to thus provide an advantageous pattern of the pivotal movement of the load carrier while the latter is being lifted from a starting position to an unloading po- sition.

The inventive elevator device is adapted to allow exchange of follower of different kinds to suit the lift- ing unit and the column in dependence on the requirements on the lifting range and the radius of the pivotal move- ment of the load carrier. This arrangement gives an addi-

tional advantage in the industrial manufacture of the in- ventive elevator device, since the same basic model may be used to suit a large number of different entrances, as it is easy to exchange a follower the groove of which has an extension that is suitable for the intended entrance.

In the inventive elevator device, the guide com- prises a pin for at least guiding engagement in the groove. Preferably, the pin is devised so as to make pos- sible also at least some load transfer between the guide and the follower. Consequently, the invention allows the pivotal movement of the load carrier to be effected at a preferred level in a most simple manner because the piv- otal movement is controlled by the position of the guide relative to the curved groove. The guide could be e. g. a simple stud that may be attached at the desired level in a simple manner.

In a preferred embodiment of the invention, the ele- vator device is fitted with a load carrier comprising a platform-supporting runner, which runner together with the platform is arranged to slide relative to the support structure in a plane that essentially is perpendicular to the extension of the column. As a result, also the plat- form may be arranged for sliding movements without addi- tional power supply being required. The runner may slide between two lateral extreme positions in response to at least two mutually tightened traction elements, which in- terconnect the runner and the lifting unit from opposite directions relative to the runner sliding-direction by suitable deflection of the traction elements, being acti- vated when the lifting unit causes vertical displacement of the load carrier to displace the platform forwards or backwards, respectively, between said lateral extreme positions, one of the traction elements pulling the

sitions, one of the traction elements pulling the runner and consequently the platform in the desired direction.

The invention thus provides an elevator device which, by means of a single power unit, permits displace- ment of a platform perpendicularly to the vertical exten- sion of the elevator device, as well as lifting a load carrier, lowering it alongside and pivoting it about a vertical axis.

In accordance with the inventive idea the load car- rier of the elevator device comprises a platform fitted with side members at the platform edges, said side mem- bers preferably being hinged. This arrangement allows convenient rolling-on and rolling-off of a wheelchair or the like. Because the side members may be folded upwards, there is no risk that objects or persons may slide off the elevator platform supporting them.

The use of one single motor should not either be re- garded as a restricting factor but rather as an important advantage in normal use of the device. In order to deal with certain extreme situations the inventive elevator device could very well be given extra power in the form of e. g. additional motors. In some cases, when the inven- tive elevator device is positioned adjacent very special stairways, also the guide may be arranged to be moved and be locked in position.

For instance, in the case of stairways the steps of which are very deep and low, there is an increased risk when using a conventional elevator device that the lower face of the platform, when the latter is being lowered, hits some part of the stairway. This risk may be elimi- nated for instance by arranging the guide such that it may slide along a vertical track in parallel with the ex- tension of the column such that owing to its movability

it may affect the pivotal pattern of the pivotal movement of the load carrier.

It should be appreciated that it obviously is within the inventive idea of a device of the kind defined above to combine the characteristic features freely or to use them as separate embodiments. For instance, it should be understood that the various displacement movements that take place during a lifting operation may be effected in different stages and combinations. The control of the very lifting movement and other operations obviously could be effected in different ways, for instance manu- ally, by remote control, or to some extent be automated.

The elevator device in accordance with the invention could be supplemented in a simple way by some desired safety equipment, such as safer anchorage. Another advan- tage gained by the invention is that the platform may be folded upwards from its position in the horizontal plane.

Owing to this arrangement, it takes up only a small part of the ground surface when not in use.

An additional object of the inventive elevator de- vice is that it should be simple to mount and dismantle.

Thanks to the considerable reduction in weight that is obtained as a result of the lesser number of power units compared with those used in prior-art structures, an ele- vator device has been provided wherein each one of the components included therein may also be made lighter.

This is a considerable advantage, considering that eleva- tor devices of this kind for various reasons often need to be moved. In this case it is a great advantage that mounting and dismantling may be performed by one person only, which is made possible in accordance with one pre- ferred embodiment, wherein each component has a maximum weight of 25 kilos.

Brief Description of the Drawing Figures The invention will be described in closer detail in the following by means of preferred embodiments and with reference to the accompanying drawings, wherein: Fig la is a perspective view of one embodiment of the elevator device mounted adjacent a stairway and with the platform in the folded-down position.

Fig lb is a perspective view of one embodiment of the elevator device, showing the platform in an enlarged partial view in a folded-down starting position.

Fig lc is a perspective view of one embodiment of the elevator device while being lifted.

Fig ld is a perspective view of one embodiment of the elevator device in an unloading position adjacent a stairway.

Fig 2a is a partial view of a follower in engagement with a guide in accordance with a preferred embodiment of the invention.

Fig 2b is a partial view of a preferred embodiment of the invention, showing the guide in an extreme posi- tion relative to the follower.

Fig 3 is a partial view of a preferred embodiment of the invention, showing the guide in an exploded view.

Fig 4a is a perspective view of a preferred embodi- ment of the invention as seen from a different direction from that of Fig 1 and showing the rear face of the stand supporting a runner.

Fig 4b is a perspective view of a preferred embodi- ment of the invention as seen from another direction than that of Fig 4a, the device being in a lifted position, and showing the rear face of the stand supporting an ex- tended runner.

Fig 5 is a view of an alternative embodiment of the elevator comprising two lifting units.

Detailed Description of Preferred Embodiments The elevator device 1 of Figs la-ld comprises a power unit 2, a lifting unit 3, both of which are sup- ported by a support structure. The latter preferably is arranged at the side of a stairway 11 in order to make it easier for disabled persons to reach the top of the stairway 11. In addition, an essentially vertical column 10 is fitted on the support structure. Preferably, the column 10 has a circular cross-sectional shape. In this drawing figure and in the rest of this document, the sup- port structure has not been given a separate reference numeral but the expression support structure refers gen- erally to the static part of the elevator-device struc- ture. In most embodiments the column could be considered as a part of the support structure.

In a preferred embodiment of the invention the power unit 2 supplies power to the lifting unit 3, which is a piston-and-cylinder unit or similar drive device. A sleeve 4 is mounted for sliding movement about the column 10. The lower part of the lifting unit 3 is connected to the sliding sleeve 4. The sleeve 4 is surmounted by a follower 7, said follower too preferably extending about the column 10. In a preferred embodiment, the follower 7 is tubular and arranged to slide along and to pivot around the column 10. The follower 7 is formed with a groove 8 having a predetermined extension and path.

The follower 7 is rigidly joined to a load carrier 19. The load carrier 19 supports a runner 9 for sliding movement, said runner in turn supporting a platform 5.

Because it is attached to the runner 9, the platform may

be slid at right angles to the extension of the column 10.

The pattern of movement of the elevator device will be described in the following with reference to Figs la- ld. In Fig la, directional arrows A and B indicate re- spective reference planes. In Fig la, the elevator device 1 is shown in its lowermost position, the platform 5 be- ing folded into an upright position to occupy less ground space. In the next sequence, shown in Fig lb, the plat- form 5 occupies its folded-down position and also some of the platform sides or side members 6 are folded downwards to allow roll-on or loading. The load carrier 19 assumes its lower starting position and the lifting unit 3 then is in its maximum extended position, as appears more clearly from the enlargement. The enlargement also shows in more detail the coupling arrangement between the lift- ing unit 3 and the sleeve. In the lower starting posi- tion, the spacing between the runner 9 and the column 10 is the maximum one.

In the next figure lc, the lifting unit 3 is shown when affected by a retracting force from the power unit 2, which force pushes the sleeve 4 upwards along the col- umn 10 and consequently also urges the follower 7 up- wards. Simultaneously with the resulting lifting of the entire load carrier 19, the latter is also pivoted towards the stairway 11. The manner in which this pivotal move- ment is achieved will be described in closer detail with reference to Figs 2a-2b. During the very lifting of the load carrier, its platform side members or sides 6 may be in either their upwardly or downwardly folded position.

The lifting movement likewise affects at least two trac- tion members 14, with the result that the runner 9 is pulled inwards towards the column, along its sliding

track. In this manner, the runner and therefore the plat- form 5 are driven forwards successively and finally reach the side of the stairway, a position that essentially co- incides with the completion of the lifting and pivotal movements. This second extreme position of the elevator device 1 is shown in Fig 1d. In this position, the lift- ing unit 3 assumes its maximum contracted position. Also in this second extreme position it is possible to fold the platform 5 into an upright position in order for it to occupy less space. To lower the elevator device again the corresponding sequence of steps as related above is effected but essentially in the reverse order.

Fig 2a shows the follower 7 in accordance with one embodiment in more detail. The follower is designed to slide along and to pivot about the column 10. The thick- ness of the material of the follower 7 preferably is about 10 mm. It may be made of e. g. steel. In the jacket face of the follower is milled a groove 8 in the form of a track-delimiting slot. Fig 2a also shows the engagement of a guide 12 in the groove 8 while assuming the first extreme position corresponding to the lower position of the follower 7. In Fig 2b, the follower 7 has been lifted and the guide 12, which in accordance with a preferred embodiment is fixed relative to the follower 7, assumes its second extreme position in engagement with the lower part of the groove 8. Owing to the configuration of the track formed in the jacket face of the follower 7, said follower 7 is forced to perform a pivotal movement rela- tive to the fixed guide 12, when the follower is moved by the lifting unit 3 upwards or downwards along the column 10.

In accordance with a preferred embodiment of the in- vention shown in more detail in Fig 3, the guide 12 com-

prises a stud which is attached to a plate. A washer 13 is applied about the stud 12 for engagement with the fol- lower 7 on either side of the groove 8. The washer could be made e. g. from oiled Teflon@. In order to improve the abutment of the washer 13 against the follower 7 a flat and smooth face is milled in said follower in the area closest to the groove 8. The flat and smooth face ensures even force distribution between washer 13 and follower 7, reducing the stress on the guide 12 compared with the case, had the contact surface of the guide 12 against the follower 7 not been flat.

Fig 4a shows the elevator device from another direc- tion. The figure shows the arrangement of the traction elements 14 in accordance with a preferred embodiment to impart to the runner 9 a pulling force enabling the run- ner to be moved forwards and backwards. In this case, the traction elements 14 are wires. In a preferred embodiment of the invention a wire extends in a taut condition from a connection 17 on the runner 9 in a direction away from the column, around a pulley and back towards the column, around another pulley and up to a plate running in a ver- tical groove, which is indicated by a dotted line in the drawing figure and which extends in parallel with the column 10 and preferably is formed in the support struc- ture. An additional traction element 14 in the form of a wire is associated with the plate and extends upwards along the column 10, past a restriction at the end of the vertical groove, and inwards towards the runner to be at- tached to the connection 17. This arrangement is an exam- ple of how a pulling force may be provided to move the load carrier 19 in the elevator device 1 by transfer of the motive force from the changing of levels to exerting a pulling force on the load carrier 19. The pulling force

acting from one or the other direction, depending on whether the lifting unit urges the load carrier upwards or downwards is used above all to ensure that the plat- form reaches a desired position relative to the ground in one extreme position and the top of the stairway in the opposite extreme direction.

In order to prevent the wire from being damaged by being deflected at too small a radius, difficult passages may become possible by enclosing the wire in a cover be- tween two points in order thus to retain the tautness of the wire. This solution is shown in some places in Figs 4a and 4b, respectively. The plate received in the verti- cal groove preferably is fitted with a gas-operated spring 16 acting against the support structure in order to make it possible to keep the traction elements 14 taut at all times. Fig 4b shows the elevator device 1 with the load carrier 19 in the lifted position. In this position, the runner 9 assumes its position closest to the column 10. The gas-operated spring 16 assumes its most extended position.

The groove 8 may be configured in a variety of dif- ferent ways, provided that the inventive function of the complementary engagement with a guide to force the fol- lower 7 to pivot about a vertical axis while being moved vertically, is not relinquished. The groove 8 could thus comprise e. g. a protrusion fittingly enclosed by a guide 12 on either side of the protrusion. Also other varieties of a groove defining the track of a guide are possible.

Fig 5 shows an alternative embodiment of the inven- tion in a lateral view, wherein an auxiliary lifting unit 15 is. provided to impart additional lifting power to the elevator device. The auxiliary lifting unit 15 is a pis- ton-and-cylinder unit or some other type of spring-action

element. When the ordinary lifting unit 3 is to pull the load carrier 19 upwards, the auxiliary lifting unit 15 is in its retracted position and is able to supply a return- ing force to give lift to the elevator device. When the elevator device is again lowered to the ground, the spring is compressed again and is able to again provide upwards lift for the following lifting operation. It should be appreciated that this auxiliary lifting unit may be positioned in many different ways, and Fig 5 shows one way, according to which it is positioned in abutment against solid ground at one end and against the sleeve at the opposite end. In order to obtain this spring action the expert in the field may make his choice from a number of optional alternatives to achieve the desired function, and the arrangement referred to above should be regarded only as one presently preferred embodiment.

It should be appreciated that several modifications of the embodiment described above are possible within the scope of protection of the invention, as the latter is defined by the appended claims. As described for example above, the shape of a platform side element or side 6 may be varied depending on existing requirements or other preferences without departing from the main idea of the invention. The expert in the field is assumed to possess such thorough knowledge of suitable choices of materials that no such materials have been specified in detail, ex- cept when to describe important features of the inven- tion. It should also be appreciated that the elevator de- vice is particularly useful for the disabled and the mo- tor-handicapped to allow them access to for example raised entrances. The elevator device may likewise be used for transportation of goods on vehicles and so on.