The present invention refers to a locking system on the sphere of a towing hook for motor vehicles. In particular, the invention refers to a system used to lock a device on the sphere of a towing hook, for example a bicycle carrier, a ski carrier, a loading platform, or any device suitable for being installed on a towing hook mounted on the rear of a motor vehicle. Locking systems on the sphere of a towing hook for motor vehicles are known, in particular a sphere with a diameter of about 50 mm made according to the ISO50 standard, comprising two parts called "scrolls" which, through a movement of connecting rods and a closure of the toggle braces type, are attached to the sphere.

This known locking system is operated by a user by means of a lever, and the closing force of the toggle on the scrolls is adjusted by means of a screw, which adjusts the bottom dead center. However, these known devices are not satisfactory and have the problem that, if the installation or adjustment of the locking system by the user is not carried out correctly, there is a risk that the device fixed to the towing hook will become disconnected, because due to stresses, vibrations, jolts, the locking system could accidentally open and cause the device or the load transported along the road to be lost. Object of the present invention is solving the aforementioned prior art problems by providing a locking system on the sphere of a towing hook for motor vehicles, in particular that is self-locking, which prevents accidental opening and guarantees a safety closure in all installation and working conditions.

The aforementioned and other objects and advantages of the invention, which will emerge from the following description, are achieved with a locking system on the sphere of a towing hook for motor vehicles such as the one described in the main claim. Preferred embodiments and non-trivial variants of the present invention form the subject of the dependent claims.

It is understood that all attached claims form an integral part of the present description.

It will be immediately obvious that innumerable variations and modifications (for example relating to shape, dimensions, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention as appears from the attached claims.

The present invention will be better described by some preferred embodiments thereof, provided by way of non-limiting example, with reference to the attached drawings, in which:

- FIG. 1 shows a perspective view of a locking system on the sphere of a towing hook for motor vehicles according to the present invention in the closed position;

- FIG. 2 shows a side view of a locking system on the sphere of a towing hook for motor vehicles according to the present invention in the open position;

- FIG. 3 shows a side view of a detail of a locking system on the sphere of a towing hook for motor vehicles according to the present invention in the open position;

FIG. 4 shows a side view of a detail of a locking system on the sphere of a towing hook for motor vehicles according to the present invention in the closed position; and

FIG. 5 shows a side sectional view of a locking system on the sphere of a towing hook for motor vehicles according to the present invention in the closed position.

With reference to the figures, the locking system 10 on the sphere of a towing hook for motor vehicles according to the invention comprises a structure 1 comprising a first fixed scroll 2A and a second mobile scroll 2B, a movement system 15, 16 configured to operate the second mobile scroll 2B by locking or unlocking a sphere 12 of the towing hook 11 between the two scrolls 2A, 2B, said movement system 15 being operated by a lever 3, said locking system 10 further comprising locking means 4, 5 configured to stop when the lever 3 is in a closed position, preferably in the lowered position, preventing it from lifting and releasing the sphere 12 by operating the movement system 15, 16 and the mobile scroll 2B.

Preferably, the locking means comprise a locking element 4 rotatably connected around a pin 7 to the structure 1 which, in the event of accidental opening of the system, interferes with a tooth 5 associated with the lever 3, for example obtained in the lever 3, to prevent the lever 3 from lifting and unlocking the mobile scroll 2B. Preferably, the movement system comprises a toggle 15 operated by the lever 3 by means of a movement of connecting rods 16; the closing force of the toggle on the scrolls 2A, 2B is adjusted, for example by means of a screw 18, which adjusts the bottom dead center.

Preferably, the locking system 10 of the invention further comprises an elastic element 19, for example a spring, which pushes the locking element 4 against the tooth 5, ensuring that the locking element 4 is always in the locking position, once the lever 3 is closed.

Preferably, the lever 3 also comprises a button 6, connected to the locking element 4, which is operated to lift the locking element 4 so as to release it from the tooth 5, allowing the lever 3 to be raised to release the sphere 12, opening the second mobile scroll 2B, so as to install or uninstall the device on the sphere of the towing hook 11; preferably, the button 6 can be rotated on a fulcrum 29 and includes an end resting on the locking element 4 to lift it when the button 6 is pressed, releasing it from the tooth 5.

Preferably, the locking system 10 of the invention comprises a lock 8 to which a hook 9 is fixed which, by rotating with the lock in the closed position, engages in a projection 14 of the locking element 4, consequently blocking the operation of the button 6 and the opening of the lever 3, thus preventing a theft of the product on the towing hook 11.

In the operation of the locking system 10 on the sphere of a towing hook for motor vehicles according to the invention, the locking element 4 interferes with the tooth 5, preventing the lever 3 from lifting and unlocking the second mobile scroll 2B. Once the lever 3 is closed, the spring pushes the locking element 4 towards the tooth 5, always ensuring the locking of the system, to ensure that the locking element 4 is always in the working position.

To install/uninstall the product from the towing hook 11, it is necessary to lift the lever 3 to position the second mobile scroll 2B in the open position, by pressing the button 6 to release, lifting it upwards, the locking element 4 from the tooth 5.

Finally, the lock 8, when closed, blocks the operation of the button 6 and the opening of the lever 3. Advantageously, the locking system on the sphere of a towing hook for motor vehicles according to the invention prevents accidental opening and guarantees a safety closure under all installation and working conditions.