Elevator Device

Scope and background of the invention

The invention relates to a system for displaying messages or the like by means of a lift. The invention also relates to a lift with such a system. In, for example, shopping centres, hotels and other public buildings an open glass-roofed hall or the like is often found which extends vertically over a number of storeys, with the storeys arranged around the glass- roofed hall. In such halls, so-called panoramic lifts are often used principally to transport persons between the floors. A characteristic of panoramic lifts is that they have an open lift shaft that is quite visible from the hall. The lift car is guided along rails or the like that are arranged on a vertical rear wall in the lift shaft. The lift car is usually driven by an electric, frequency-controlled motor which is connected to the lift car for example by means of cables and which is mounted at the upper or lower end of the lift shaft.

With such an open lift shaft the desire often exists to conceal the back vertical wall holding the rails. Furthermore, there is often a desire to be able to exploit the movement of the lift for effective display of messages such as advertising or of decorative features .

Prior art Securing a system resembling a rolling window blind at the bottom of the lift shaft has been previously known with a cylinder on which a long width of cloth or the like has been secured and rolled up. The free end of the width is fixed to the lift car. On the side of the width facing the hall, advertising messages or decorations can be printed. When the lift ascends the width is rolled out, whereupon the message or decoration becomes visible from the hall. When the lift descends, the width is rolled up again on the roll.

With these previously known systems the rolling up is accomplished, as with conventional rolling window blinds, by a spring that is tensioned during the unrolling. An example of such a previously known system is disclosed in EP 0 700 858 Al.

Such previously known systems have drawbacks in part because the spring design places an upper limit on the possible length of the width. In addition, with such previously known systems an increasingly large tensile force can be established in the width, with the risk that the tensile force will damage the width or the spring.

Brief description of the invention One object of the present invention is to provide an improved system for displaying messages and the like on a panoramic lift.

Another object is to provide such a system that is reliable and dependable. A further object is to provide such a system that can be used on even very high lift shafts.

These and other objects are achieved with a system of the type defined in the preamble to patent claim 1 and which displays the distinctive features defined in the claim.

According to the invention, the cylinder onto which the width is rolled is driven by an electric motor. The motor can easily be controlled so that the width has the same speed when being rolled up as the lift car. In this way it is possible to regulate with great precision the tensile stresses that arise in the width, thereby considerably reducing the risk of the width being damaged.

In order to obtain the advantagtes of the invention it is sufficient for the motor to be coupled in when the width is being rolled up. At least with shorter widths, where the system is placed below the lift car, it can be sufficient for the motor to drive the roll for

rolling up, whereas the movement of the lift car itself pulls the roll out when the lift car ascends . The system is however designed such that the motor will drive the cylinder both in the rolling out and in the rolling up directions. In this way placement of the system above the lift car is also possible. At the same time, such a design permits the use of very long widths without there being subjected to any harmful tensile forces . The motor is ideally frequency-controlled. This achieves reliable control of the motor in a simple manner, whereby the controls ensure that the rotational velocity of the cylinder always corresponds to the speed of the lift car. The system ideally includes a control unit to which the motor is connected electrically. The control unit is arranged to drive the motor in the rolling up and/or out directions such that the width is rolled up and out respectively subject to a controlled tensile force within the width. In this manner it is possible to obtain a well-balanced tensile force in the width, but with a tensile force ensuring that the width is kept stretched for optimum display of the message, while at the same time not risking damage to the width due to an excessive or fluctuating tensile force.

The system ideally includes an adjusting device which is connected to the control unit and arranged so as to allow adjustment of the tensile force in the width while the width is rolled up and out respectively. In this way the system can be simply adapted for use under different conditions involving, for example, the height of the lift shaft and the dimensions and weight of the width. The system can be designed such that the motor is electrically disengaged from a lift motor designed for driving the lift car, and likewise from feed and control arrangements connected to the lift motor. In this manner a completely separate unit is obtained

which can be installed simply and which only needs to be connected electrically to a voltage source. Alternatively, the motor can be connectable to an existing control unit for controlling the lift motor which drives the lift car. In this embodiment the control unit of the system can be dispensed with while at the same time permitting relatively simple installation, where the motor is coupled to already existing wires for controlling the lift motor. Further advantages and characteristics of the invention appear in the detailed description below and the subsequent patent claims . Brief description of figures In the following, an exemplary embodiment of the system in accordance with the invention will be described with reference to the figures, in which:

Fig. 1 shows a schematic diagram of a panoramic lift for which two systems according to a first embodiment of the invention are arranged. Fig. 2 shows a schematic diagram of a panoramic lift for which a system in accordance with a second embodiment of the invention is arranged. Detailed description of an embodiment A panoramic lift is shown in the figures with a lift car (3) which by way of a cable (9) is connected to a lift motor (8) that is secured at the upper end of the lift shaft. The lift motor (8) is in the usual manner frequency-controlled by a control unit (6) which is connected to the lift motor (8) via a wire (10) . In fig. 1, a system is shown in accordance with a first embodiment of the invention. The system is arranged below the lift car (3) and includes a rotating cylinder (2) which is connected to an electrical frequency- controlled motor (1) . The cylinder and motor are ideally integrated into one unit that is secured to the lift shaft below the lowest position of the lift car, for example to the floor at the bottom of the lift shaft. A width (4) of a flexible material, either cloth or plastic film which can be provided with

appropriately printed advertising or decorations has its one end secured at the cylinder (2) . The other end of the width (4) is secured to the floor of the lift car (3) by way of a spring- loaded terminal strip (5) . The motor (1) is connected by way of a signal wire (11) to the wire (10) for controlling the lift motor. Alternatively, the motor (1) can be connected directly to the existing control unit (6) or to the lift motor (8) . As shown in fig. 1, there is also a system (7) arranged above the lift car. The cylinder and motor in this other system are ideally secured as one unit in an existing machine room above the highest position of the lift car. The free end of the width of the other system (7) is secured to the roof of the lift car.

Both of the systems thus allow simple retro- fitting to pre-existing panoramic lifts. Since the system according to the invention is arranged advantageously both below and above the lift car, very impressive display of messages or decorations is permitted.

Furthermore, the systems allow for very long widths to be utilized without the risk of damage. In this manner, messages can also be displayed on panoramic lifts and the like in very tall buildings. In fig. 2, a system is shown in accordance with a second embodiment of the invention. This system is arranged below the lift car and includes a motor (1) and a cylinder (2) on which a width (4) is secured. The motor (1) for this embodiment is also frequency- controlled, but the control of the motor is different from the embodiment described above. The system shown in fig. 2 is electrically completely disconnected from the lift motor (8) and from the controls (6, 10) and supply of the lift motor. Instead, the system includes an electrical control unit (20) in order to frequency- control the motor (1) . The control unit (20) is connected to a voltage source suitable for three-phase alternating voltage. The control unit includes an adjusting device (22), for example a manually

adjustable potentiometer. The control unit (20) is further connected via a wire (21) to the motor for supply and control of the motor. The control unit (20) includes a means for sensing the motor moment. For example, this sensing could be effected by measuring the current or power consumption of the motor. The control unit can in this way drive the motor (1) to rotate in a direction that rolls up and/or out such that a controlled tensile force is established in the width during the entire rolling up and out respectively of the width. By regulating the adjustment device (21) of the control unit (20) it is possible to adjust the tensile force generated by the motor in the width. For the embodiment shown in fig. 2, very simple installation of the system is enabled since the system can be electrically disconnected from the other electrical components of the lift. At the same time, very good control of the tensile force in the width is allowed, such that the width can be kept stretched in order to obtain optimum display of the message, while at the same time the risk of damage to the width due to excessive or fluctuating tensile forces is either reduced or eliminated completely.

Examples of embodiments have been described above. It should be noted however that the invention is not limited to these embodiments but that it can be freely varied within the framework of the subsequent patent claims. For example, the lift shown in figure 2 can of course be equipped with two systems, just as the lift shown in figure 1 can be equipped with only one system.