The swivelling doors currently used in car parks are operated by a motor which acts through a set of gearwheels on a shaft, rotation of which gives rise to opening and closing of the swivelling door.

These currently known swivelling doors have the disadvantage that they can remain blocked accidentally, whether by their mechanism of gearwheels or due to lack of electrical current feed to the motor.

Should such blocking occur, it is at present necessary to gain access to the interior of the car park in order to unblock the door. When they are blocked, these doors cannot be opened and closed in order for them to be unblocked by persons who know how to carry out such unblocking.

The operating device of the invention achieves a solution to the aforesaid disadvantages, while presenting other advantages which will be described below.

The operating device of this invention for swivelling doors is characterised in that said shaft is coaxial to a gearwheel with helicoidal teething, which meshes with an endless screw.

Thanks to this characteristic, it is possible to open and close the swivelling door manually in the event of emergency, without it being necessary to gain access to the interior of the car park. Moreover, thanks to the arrangement of the endless screw, the mechanism is reversible, that it, it can be rotated in both directions without need for the motor to operate.

According to two alternative embodiments, between the motor and said endless screw there is a reduction-

gearwheel assembly or, alternatively, the operating device of the invention includes a hydraulic operating unit between said motor and said endless screw.

The utilisation of a hydraulic operating unit means that work takes place with low pressures when compared with the hydraulic units used with swivelling doors, thereby avoiding many breakdowns.

If so wished, the operating device of the invention can also include means of control to regulate its power.

For a better understanding of all that is disclosed in this specification some drawings are attached which, solely by way of example, show a practical case of embodiment of the operating device of this invention.

In said drawings, Figure 1 is a perspective view of a first embodiment of the operating device of this invention in partial cross-section view; and Figure 2 is a perspective view of a second embodiment of the operating device of this invention in partial cross-section view.

As can be appreciated in Figure 1, the operating device of this invention includes an electric motor 1 which, through a set of gearwheels, drives the rotation of a shaft (which would be housed in orifice 2), thus causing opening or closing of the swivelling door.

Said shaft is coaxial to gearwheel with helicoidal teeth 3, which meshes directly with an endless screw 4.

Thanks to this arrangement of the endless screw 4 it is possible to open and close the swivelling door manually in the event that operating it by means of the motor is accidentally blocked.

Linked with this endless screw 4 is mounted a gearwheel with straight teeth 5, which in turn meshes with a reduction unit of gearwheels 6 linked with the electric motor 1.

The embodiment of Figure 2 differs from the embodiment of Figure 1 in that between the electric motor 1 and the toothed wheel 5 is mounted a hydraulic pump 7 and a hydraulic unit 8, through which movement is transmitted to the endless screw 4 and, in consequence, to the shaft that causes opening and closing of the swivelling door.

Said hydraulic unit 8 also includes some valves 9 for adjusting the power that it transmits to the operating device, with said hydraulic unit 8 also driving a piston 10 for the lock of the swivelling door.

Both the embodiment of the operating device of this invention shown in Figure 1 and that shown in Figure 2 can include electronic control means to regulate the power thereof.

Despite the fact that reference has been made to specific embodiment of the invention, it will be obvious to a person skilled in the art that the operating device disclosed allows of many variations and modifications, and that all the details mentioned may be replaced by others that are technically equivalent, without departing from the scope of protection defined in the attached claims.