Current use has long been made of self-adhesive tapes or bands, of paper, plastic, fabric, metal, made adhesive by application of a film of a suitable substance for joining objects together or for providing a protective surface layer.

Also known are abrasives of various kinds such as sandstone, corundum, emery, diamond powder incorporated in conglomerates and used in grinding wheels or mounted on flexible supporting means.

Purpose of the present invention is to facilitate the use and replace- ment of said abrasives in their innumerable functions, as will here be explained.

Subject of the invention is a process for producing reels of abrasive self-adhesive band.

A multi-layer band comprising a metal band, a first self-adhesive layer onto one face, here called the inner face, of said metal band, and a protective strip for said self-adhesive layer, is spirally wound on said inner face, in turns one close against the next, round an electrodeposition roller.

Said spiral of multi-layer band is made to adhere to the electro- deposition roller by means of clamps at each end.

In another type of execution said spiral adheres to the roller by means of a second self-adhesive layer that externally covers the protective strip, laid over the first self-adhesive layer, and therefore the inner face of the multi-layer band.

In another type of execution adherence of said multi-layer band to the roller. is obtained both by the clamps and by the second self- adhesive layer.

The roller is then immersed in a bath for electrodeposition of abrasive granules.

After electrodeposition the band is unwound from the roller and wound up to form a reel the outer metal face of which is coated with the granules of abrasive.

The metal band is advantageously of stainless steel.

The abrasive is advantageously diamond powder.

In one type of execution the process comprises a coating, consisting of a layer perforated with a pattern, applied by a silk- screening process to the outer face of the multi-layer band.

In another type of execution the multi-layer band comprises a third self-adhesive layer on the face, here called the outer face, of the metal band, and a covering strip in which perforations form a certain pattern.

As a result, electrodeposition of abrasive on the outer face of the metal band will only take effect at the position of said perforations.

In one type of execution the perforations are circular and therefore the areas covered by abrasive are also circular.

in one type of execution the protective strip for the first self- adhesive layer, and the covering strip with perforated areas, are made of paper.

In another type of execution the protective strip for the first self- adhesive layer and the covering strip with perforated areas, are made of plastic material.

Abrasive self-adhesive metal reels are obtained by this process.

The variant form of the process provides a reel of abrasive self- adhesive metal band whose abrasive areas form a certain pattern.

The invention offers evident advantages.

Wherever a tool is needed for lapping or for removing layers of material of varying thickness, not only can lengths of abrasive self- adhesive band, subject of the invention, be used but ; just as convenient, is their quick replacement when worn, thereby exploiting the characteristics inherent in a self-adhesive band rendered abrasive, as described in the invention.

At the present time, where the lapping support is a heavy tool, replacement of the abrasive part on said tool is always a lengthy and costly operation.

Where the support is light, such as sand paper for example, it gives way easily after a very short period of use, preventing or greatly limiting the effectiveness of abrasive action.

The present invention, permitting stable association between a metal band, coated by electrodeposition with abrasive, and the operative base of a tool, or even of any strong support, enormously assists lapping operations which can thereby become both less costly and more efficient.

As needs require, lengths of one or other of the abrasive bands can be used for work of varying degrees of fineness, according both to the type of abrasive on the band, and to the shape of the abrasive areas present.

Characteristics and purposes of the invention will be made still clearer by the following examples of its execution illustrated by diagrammatically drawn figures.

Fig. 1 A reel of multi-layer band and detail cut through, perspective.

Fig. 2 The multi-layer band being spirally wound onto a roller for electrodeposition with granules of abrasive, particularly diamond granules, perspective.

Fig. 3 The roller in Figure 2 when the band has been wound on and after electrodeposition, perspective.

Fig. 4 The multi-layer diamond-coated band when being unwound from the roller and rewound to form a reel, perspective.

Fig. 5 The completed diamond-coated multi-layer band, perspective.

Fig. 6 Reel of a multi-layer band comprising a paper strip with perforated areas to produce e ! ectrodeposition to a pattern, with detail cut through, perspective.

Fig. 7 The multi-layer band in Figure 6 being spirally wound onto a roller for electrodeposition, perspective.

Fig. 8 The roller in Figure 7 after the multi-layer band has been completely wound on, and after electrodeposition, perspective.

Fig. 9 The multi-layer band, diamond-coated to a pattern, being unwound from the electrodeposition roller, and wound up into a reel with removal of the perforated strip, perspective.

Fig. 10 The completed multi-layer band, diamond-coated according to a pattern, perspective.

Figure 1 shows a reel 11 consisting of a multi-layer band 10 comprising a metal band. 15, a first adhesive layer 16, a protective strip 17 held in place by a second adhesive layer 18.

The mullti-layer band 10 is spirally wound onto the roller 50 of insulating material, such as rubber, with pins 51, the band being held firm to the roller at the ends by clamps 55 (Figure 2).

Having completed winding, the roller is put into a bath of liquid for electrodeposition of abrasive granules 20, particularly diamond granules.

After electrodeposition the band 15 emerges coated with diamond granules 20 and is now numbered 25 (Figure 3).

Band 25 is then unwound from the roller 50 and wound up on itself to form a reel 26 as seen in Figure 4.

Figure 5 shows the completed reel 26.

Figure 6 shows a reel 31 of multi-layer band 30 that differs from multi-layer band 10 having, on the outer face of the metal band 15, a strip of paper 36 with perforated areas 38, following a certain pattern, held in position by a third layer of adhesive 35.

Similarly, said multi-layer band 30 is spirally wound onto a roller 50 (Figure 7) and then coated, by electrodeposition, with diamond granules as done for the multi-layer band 10.

The diamond granules only adhere to the metal band 15 at the position of perforated areas 38 present in the strip of paper 36 which then become diamond-coated areas 39.

At the end of electrodeposition said band 30 appears as in Figure 8 and becomes the band numbered 40.

Said band 40 is then unwound from the roller 50 and wound up on itself, with simultaneous detachment of the perforated strip 36, so forming a reel 41 (Figure 9).

Figure 10 shows the completed reel 41.