It is previously known to let the grinding disc be carried in such a way, that it can move to some extent when uneven floors are grinded. Then, the grinding disc has been carried by means only of a flexible sleeve of rubber, or in combination with fabric of desired textile, i.e. the type of rubber bushings, which exhibit carriers of different types of fabric associated with the output shaft of the grinding machine and a plate in order to be able to take up unevenness in the floor, and also various types of universal joints.

The security for the persons using such grinding discs has not been so good. Frequently, they carry out work, where it is uncertain if the surface which they grind contains hidden and/or visible, protruding and/or hard objects, which cannot easily be grinded away. On such occasions the known flexible hubs have been damaged and broken due to hard external influences. For example, heat is not good to rubber material which has been used. Furthermore, it has not been easy to change the flexibility of known grinding discs, for example in order to perform different types of work, which require different types of hardness and flexibility.

The main object of the present invention is to solve, among other things, the problems described above by simple and safely functioning means.

RECORD COPY-TRANSLAi lON

Rule 12,4 Said object is reached by means of a device according to the present invention, which is substantially characterized in that a lower grinding disc is flexibly carried by means of a flexible disc located in the middle, or several flexible, put together discs located in the middle, which is/are arranged between the lower grinding disc and a rotatable output shaft.

The invention is described in the

following as a preferred embodiment with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a grinding disc with a flexible hub according to the invention,

Fig. 2 is a lateral view of said grinding disc with associated device,

Fig. 3 is a plan view of said grinding disc seen from it underside,

Fig. 4 is a perspective view of a grinding disc with included parts, and

Fig. 5 is an exploded view of such a grinding disc according to the invention.

The invention solves the problem when one or more hubs are mounted on a grinding machine, where the hub is to follow the surface being grinded, and where the output shaft from the grinding machine is relatively rigid in relation to the surface intended to be grinded, and where, thus, a flexible hub is needed to be able to take up unevenness of the surface in an efficient and safe way, and in order to achieve efficient finishing.

By means of the present invention it is possible to see to it in a reliable and safe way, that the lower grinding disc, which is made of steel, can move to a certain extent in different angles in relation to the shaft of the grinding disc. This is achieved by means of one or more packed discs of spring steel, which are held by means of a number of spacing bodies, so called spacing nipples, which are four in number. The height of these spacing nipples limits the flexibility and bendability of the spring steel discs.

The invention makes it possible to

increase the safety for the persons using the grinding machine. They can perform work, where it is uncertain if the surface is free from hidden or protruding harder objects, without running the risk of the hub breaking due to such external influences.

The operator can now also easily change the number of flexible discs in order to be able to perform various types of work demanding different types of hardness and flexibility. Neither does heat being

generated now destroy the putting together.

More exactly, the invention relates to a device 1 at a grinding disc 2 for a floor grinding

machine, and comprises a rotatable, from the machine outgoing shaft. According to the invention a lower

grinding disc 2 is flexibly carried by means of one or more flexible, put together discs 3 located in the middle, which are arranged between the lower grinding disc 2 and a rotatable output shaft 4.

Said put together, flexible discs 3 consist of metal material, more exactly of spring steel or similar material. Spacer blocks 5-8 are arranged to keep said flexible discs 3 at a distance A, B from the grinding disc 2 and from the shaft 4 and its associated disc 9, respectively. The spacer blocks 5-8 are distributed in pairs 5-6 and 7-8, respectively, along a common periphery 10 on either side I; II of the flexible discs 3. Preferably, said spacer blocks 5-8 are formed by cylinders of metal with a central screw hole 11, and which have a smaller diameter d at one of their ends 12 compared with their opposite end 13, where the diameter D is larger. The portion of the spacer block 5-8 having a smaller diameter d is receivable in a fitting recess 14 in said opposite, locked, flexible disc portion 3. The other end is screwed on to the grinding disc 2.

Said spacer blocks 5-8 are equally distributed along the periphery of the flexible discs 3, whereby the upper spacer blocks 7,8 are formed by two blocks, which are perpendicular to the lower spacer blocks 5,6, which are also formed by two blocks. Thereby, more than one pack of flexible discs 3 with intermediate spacer blocks 5-8 may be arranged at the grinding disc 2.

Said flexible discs 3 are attached to the grinding disc 2 and to the output shaft 4, 9 from the machine, respectively, by means of not shown screws.

The nature and the functioning of the device should have been understood from the above descrip- tion and the accompanying drawings. Thus, the grinding disc 2 with associated grinding segments, which are preferably releasably attached thereto, may be resilient around the in pairs arranged spacer blocks along an imagined first line, which coincides with a diameter 30, and around an imagined second line, which are perpendicular to said first line, and which in its turn coincide with a perpendicular diameter 31 of said discs. It is also possible to choose an angle that is not right, especially if several separate or packs of flexible spring discs 3 are kept in a common stack and pack according to the invention .

Of course, the invention is not limited to the embodiment described above and illustrated in the accompanying drawings. Modifications are possible, especially as far as the nature of the different parts is concerned, or by using equivalent technique, without departing from the scope of the invention as it is defined in the patent claims.