of the invention having the TITLE "Safety stop mechanism" to Maber Hoist S.r.l. The present finding concerns a safety stop mechanism to be mounted on lifting platforms, according to the general part of claim 1.

As known, in lifting platforms, in particular in service lifts for lifting things and people, present on construction worksites, as well as in lifts for civil use, the need to apply a safety mechanism that forces the mobile lifting plane to stop when its correct operation is compromised, due to the breaking of one of the control elements of said plane, in particular of the pinion that controls the lifting and lowering movements of the platform, acting in collaboration with a rack fixedly connected to the fixed part of the structure, is important.

Patent document EP 0385180 Bl describes a safety stop mechanism (see figs. 1-2, the following reference numerals concerns such a document) that foresees for a lever (6), mounted on a mobile frame, to engage, through a roller (8), on a rotary drum (1) fixedly connected to a pinion (11), which meshes with a rack (12); said roller is taken away by suitable cams (2, 3), foreseen on a rotary drum (1), with the consequence of bringing a second lever (6'), fixedly connected to said roller (8), equipped with an elastic contrast spring (9) closer to the aforementioned rotary drum (1).

When the operation of the platform is under normal conditions, the lever (6) lifts, moving away from the drum (1) sufficiently so as not to engage the stop cam (2, 3). Vice-versa, when, for whatever reason, something happens that prevents the correct operation of the platform, the increased rotation speed of the drum (1) would prevent the timely return into rest position of the lever (6) associated with the roller (8), which is instantaneously forced to engage with one of the projections (4, 5) fixedly connected to the drum (1), locking its rotation and in such a way stopping the platform.

Again in the aforementioned patent document, the connection between the drum (1) and the pinion (11), which transmits the rotation of both, in conditions of normal operation or, vice-versa, in conditions of failure, the stopping firstly of the drum (1) and, consequently, of the pinion (11), takes place through the interposition of a clutched disc brake made up of a disc (13), fixedly connected to a pin that supports a pinion (12), which is clamped through two friction rings (14, 15) mounted on the plates (16, 17), fixedly connected to the drum (1) and adjusted, in terms of pressure, through springs (18), mounted on pins (19).

In practice, with the immediate stopping caused by the safety stop mechanism, the amount of motion possessed by the members up until that moment in movement, in particular by the rapidly descending platform, transforms into intertia energy, which gives rise to a "recoil", which generates structural tensions and vibrations that can compromise the strength of the structure, the stability of the load on the platform and, overall, the well-being of the workers.

Patent document US 4856623 foresees a safety stop mechanism, of the type described in the aforementioned patent document EP 0385180 Bl, which, at the moment of immediate stopping of the platform, tends not to cause dangerous tensions and vibrations over the entire structure.

In such a document it is foreseen for the disc of the clutched brake to not be directly fixedly connected with the pin that supports the rotary pinion, but rather disc and pin constitute two separate elements, which are connected together through the interposition of a device, which has a damping function of the inevitable vibrations, which are generated in the case of immediate stopping, forced by the aforementioned safety mechanism.

Constructively, such a damping device substantially consists of a plurality of discshaped bodies and one or more series of elastic elements arranged on one or more circumferences which, mounted precompressed inside seats, in the case of immediate stopping, perform a damping function, allowing a compression, which absorbs part of the inertia energy.

The purpose of the present finding is to make a safety stop mechanism that is capable of providing significant improvements in terms of the generation of dangerous tensions and vibrations over the entire structure. This is obtained, according to the finding, through a device that has the characteristics of the characterising part of claim 1.

The finding will be defined more clearly through the description of a possible embodiment thereof, given only as a non-limiting example, with the help of the attached tables of drawings, where:

- fig. 1 (table I) represents a safety stop mechanism equipped with the damping device according to the finding;

- fig. 2 (table II) represents a top sectioned view of the mechanism according to fig. 1;

- figs. 3 and 4 (tables III- IV) represent section views of the damping device, according to the lines III-IIII and IV- IV of fig. 2;

- fig.5 (table V) represents an exploded view of the stop mechanism according to fig. l ;

- fig. 6 (table VI) represents perspective views of the four disc-shaped elements, making up the damping device according to the finding; - figs. 7, 8 and 9 (table VII) represent respective front section and perspective front and rear views of the elastic group mounted on the damping device according to the finding.

As can be seen in fig. 1, the safety stop mechanism 100, of the type described above, is equipped with the clutched disc brake 101 and is equipped with a damping device, wholly indicated with reference numeral 1, applied coaxially on the pin 102 of the pinion 103, which meshes with the fixed rack, not represented.

As can be seen in fig. 2, the device 1 consists of four disc- shaped bodies, hereinafter called by the generic term "discs", respectively indicated with reference numerals 2, 3, 4 and 5, as well as the elastic group 6.

In detail, the disc 2, arranged outermost, is welded to the pin 102, equipped with the rotary pinion 103, whereas two intermediate discs 3 and 4 are fitted idly on said pin 102 and the innermost disc 5 constitutes the flywheel of the clutched brake 101, mounted on the stop mechanism 100.

In detail, the fins 2.1, projecting from the disc 2, come close to the corresponding fins 3.1, projecting from the front wall of the first intermediate disc 3, whereas the projecting fins 3.2, projecting from the rear wall of the disc 3, come close to the corresponding fins 4.1 projecting from the wall of the second intermediate disc 4, which is connected to the disc 5 through a fixed connection, which holds the neck 5.1 of the disc 5 against the rear wall of the aforementioned disc 4.

The damping device 1 is completed with the insertion of an elastic group, wholly indicated with reference numeral 6, which comprises elastic elements 7, positioned between two consecutive pairs of fins.

In detail, a first series of elastic elements, consisting of precompressed springs 7.1, is positioned between the disc 2 and the disc 3 and the single springs 7.1 are inserted between the pairs of fins 2.1 and 3.1, as well as held in the seats 8.1, defined by the outer ring 9 and by the inner ring 10.1.

A second series of elastic elements, consisting of the precompressed springs 7.2, is positioned between the disc 3 and the disc 4 and the single springs are inserted precompressed between the pairs of fins 3.2 and 4.1, as well as held in the seats 8.2, defined by the outer ring 9 and by the inner ring 10.2.

Operatively, when the safety mechanism 100 and the clutched disc brake 101, which locks the disc 5, start to work, the inertia energy, due to the amount of motion possessed by the members up until that moment in movement and that is transmitted, through the pinion 103 and the pin 102, to the entire aforementioned mechanism 100, is, in part, absorbed by the elastic group 6, in which the elastic elements 7 are subjected to a compression, which generates a torque, which is transmitted through the two intermediate discs 3 and 4 and that, consequently, causes the rotation (slipping) of the disc 5, held between the brake discs (linings), which, in practice, also results in the dissipation of the remaining part of the aforementioned inertia energy. The finding thus conceived can undergo modifications and variants like, for example, the use of a single intermediate disc 3 and the elastic group is made up of a single series of elastic elements 7, which can consist of elastomeric pads, rubber rings; moreover, the constructive details, the sizes and the contingent shapes can vary, according to the design requirements and the needs of the user, provided that it is all encompassed by the inventive concept defined by the following claims.