The present invention relates to an apparatus for actuating cars or movable platforms, in particular for lifts and/or elevators, of the type comprising at least a winch.

Currently, lifts, provided with cars, and/or elevators, provided with a movable platform, are actuated by an electric motor that transmits motion to a winch through the interposition of a mechanical reduction unit coupled to a worm screw. In particular, the reduction unit usually has a high reduction ratio, in order to prevent backward motion, once the car or the elevator, with a certain load aboard, are stopped in raised position. The car and the elevator are normally sustained by a cable, partially wound about a wheel of the winch and adhering thereto, in such a way that, during rotation, there is no relative slippage between the cable and the wheel itself. Generally, the actuation means, i. e. the electric motor and the winch, are usually housed in a dedicated machinery room, obtained at the base or at the top of the system, depending on available space.

In accordance with a second prior art technique, the winch and the electric motor are mechanically connected by means of a transmission belt, preferably toothed and of the poli-V type, which acts on two pulleys mounted respectively on the electric motor and on the winch.

In both cases, an emergency brake is present which intervenes in case of failure and which allows, if necessary, to bring the lift car or the elevator to

a floor.

The technical solutions briefly described above have some drawbacks.

First of all, the energy consumption of the electric motor is independent from the size of the load to be lifted. Therefore, even when the car or elevator transport no persons or goods, energy consumption is nonetheless considerable.

Secondly, a malfunction of the electric motor entails the immediate arrest of the car and/or of the elevator and hence the impossibility of using the system.

Another drawback is represented by the fact that the potential energy associated with the lift in the descent and braking phase is not used or recovered in any way at all, thereby reducing the energy efficiency of the system.

DISCLOSURE OF INVENTION.

An aim of the present invention is to eliminate the aforesaid drawbacks, making available an apparatus for actuating cars or movable platforms, in particular for lifts and/or elevators, which is able to optimise the consumption of electric energy, varying its operation according to the load to be lifted.

Another aim of the present invention is to propose an actuating apparatus that allows to recover, possibly converting it into another form of energy, the potential energy associated with the lift in the descent and braking phase, thereby enhancing the energy efficiency of the system.

An additional aim of the present invention is to make available an actuating apparatus that is able to reduce maintenance costs and at the same time is reliable and complies with current safety regulations.

Yet another aim of the present invention is to propose an actuating apparatus

that can be applied directly to the lift car or to the elevator, reducing the size of the machinery room or even eliminating it altogether.

Said aims are fully achieved by the apparatus for actuating cars or movable platforms, in particular for lifts and/or elevators, of the present invention, which is characterised by the contents of the claims set out below and in particular in that it comprises a plurality of actuators operatively active on the winch to actuate it and means for operating said actuators in mutually independent fashion.

BRIEF DESCRIPTION OF DRAWINGS.

This and other characteristics shall become more readily apparent from the following description of a preferred embodiment illustrated, purely by way of non limiting example, in the accompanying drawing tables, in which: Figure 1 shows a front view of a first embodiment of an actuating apparatus according to the present invention; Figure 2 shows a partially sectioned lateral view of the apparatus shown in Figure 1; Figure 3 shows a front view of a second embodiment of an actuating apparatus according to the invention; Figure 4 shows a partially sectioned lateral view of a third embodiment of an actuating apparatus according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION.

With reference to the figures, the apparatus for actuating cars, in particular for lifts, and/or elevators, of the invention, is globally indicated with the number 1 and is of the type comprising at least a winch 2.

The apparatus 1 originally comprises a plurality of actuators, preferably

constituted by electric motors 3 operatively active on the winch 2 to actuate it and it is provided with means (not shown herein) for operating the motors 3 independently from each other.

In the embodiment illustrated in Figures 1 and 2, there are four mutually identical electric motors, arranged at 90° from each other along the circumference of a wheel 2a whereof the winch 2 is composed. In particular, each motor 3 has a roller 4 which exerts a certain friction on a ring 2b positioned along the perimeter of the wheel 2a and internal to the winch 2.

The electric motors 3 can be"brushless"and/or with direct current and or with single-phase or three-phase induction and/or synchronous reluctance motors. In an alternative embodiment, illustrated in Figure 3, the possibility is provided of using, in the same system, electric motors having different dimensions and power, provided they all operate at the same number of revolutions. In the illustrated embodiment, three electric motors are present, positioned at about 120° from each other along the circumference of the wheel 2a.

The means for operating the electric motors comprise at least an electronic control circuit for commanding the start of a pre-set number of motors 3 according to the weight of the load to be lifted and means for measuring the weight of the load to be lifted and send the measurement thereof to the electronic circuit. In the preferred embodiment, said means for measuring the weight of the load to be lifted comprise an electronic transducer, typically a load cell, or alternatively a normal dynamometer.

To optimise the consumption of electrical energy in the various loading conditions, it is possible to start one or more motors (which may have

different power outputs) according to pre-set load levels. Supposing, for instance, a car with load limit of 630 kg and three electric motors, only one motor is started for a load level of 200 kg or less, starting two motors for a load of between 200 and 400 kg and lastly starting all three motors for a load level exceeding 400 kg.

The electric motors 3 are preferably controlled according to two alternative modes: distributed control or centralised control.

Distributed control provides for each motor to be equipped with its own. regulator which is operated and controlled by the aforesaid electronic control circuit.

On the contrary, centralised control provides for all motors to be controlled by the same regulator and the aforementioned electronic control circuit decides which ones are to be operated.

The regulators in question are electrical circuits, typically able to control position, velocity and torque of the motor by means of an appropriate regulation system composed by functional blocks of substantially two types: - open loop, i. e. without measuring sensors and without feedback circuit; - closed loop, i. e. with measuring sensors associated with a feedback circuit.

In an additional embodiment, the regulators can include both types of controls briefly described above.

The apparatus 1 further comprises at least a safety brake 5 operatively active on the winch 2 and able to be operated at least in case of relative slippage between the winch itself and the electric motors or in case of malfunctions caused, for instance, by mechanical failures or by the lack of electrical power.

The apparatus 1 is provided with electronic means for controlling and

managing the operation of the brake 5 according to the extent of the relative slippage between the winch 2 and the electric motors 3. In the embodiments illustrated in Figures 2 and 4, the brake 5 is of the disk type, although other embodiment may provide for the use of block brakes.

During the descent of the car, the electric motors 3, exploiting the mechanical work obtained at the expense of the potential energy of the car itself or of the elevator, generate electric energy which can be reintroduced directly into the mains or stored in a battery.

Alternatively, during the descent, the motors 3 can be powered electrically, to make them exert a braking action on the car and/or on the elevator.

Lastly, the apparatus 1 comprises at least a battery for powering the electric motors 3, making the system self-sufficient in case of an interruption in the power supply from the electrical mains. In particular, the battery can be of different types, for instance lead, gel, nickel-cadmium or lithium ions.

As shown in Figure 4, the electric motors act directly on the periphery of the winch 2 and can be positioned vertically, horizontally, outside or inside the winch itself.

The invention achieves important advantages.

First of all, such an apparatus, using a number of motors that can vary according to the load to be lifted, allows to optimise the consumption of electrical energy, simultaneously reducing the lost power and hence increasing the energy efficiency of the system. With an appropriate motor start logic it is possible to reduce heating and wear on the mechanical components of the motors, also enhancing their reliability.

Secondly, such an apparatus allows to recover, at least partially, the potential

energy associated with the lift in the descent and braking phase. In particular, said energy recovery is achieved in the generation of electrical energy to be reintroduced into the mains (co-generation) or to be used to charge an accumulator and/or one or more batteries.

Another advantage is represented by the fact that, since the apparatus is provided with a plurality of electric motors, its reliability can be further enhanced by over-dimensioning the number of installed motors: if one motor fails, the system will still be able to operate correctly.

Advantageously, the presence of a plurality of motors allows to reduce maintenance costs, since the probability of failures in multiple motors simultaneously is much lower than that for a single motor.

Another advantage is represented by the fact that such an actuating apparatus can be applied directly to the lift car or to the elevator, reducing the dimensions of the machinery room or even eliminating it altogether.