The present invention relates to a process for making abrading rollers, spiral wound, i.e., coated with an abrasive tape, wound helically on their cylindrical surface and stretched at the ends, for abrading machines with one or more rollers, particularly for sheet materials, such as clothes and the like. The present invention relates also to the rollers obtained with such process, as well as the soft and speedy abrading machines comprising such rollers.

At the present state of the art the abrading machines, with one or more rollers, particularly for sheet materials, such as clothes and the like, include abrading rollers made of metallic material, thus relatively heavy, being provided with devices for radial and/or tangential tensioning. These devices are so made that render the roller unbalanced. The known devices for radial and/or tangential tensioning, were substantially of two kinds. Those of the first kind, generally mounted on machines provided with a single abrading roller, were comprised by an abrasive tape fastening unit, generally with three segment jaws, acting centripetally within a ring, enveloping each end of the roller between which and the same roller there was a groove for the abrasive tape to pass. Thus, such abrasive tape was fastened between the jaw outside and the ring inside, by a spiral device of the kind in use on self centring chucks, to drive their unit. A second kind of devices, generally mounted on machines provided with more abrading rollers, was comprised by a winch-like device, wherein the winch was provided with a diametrical groove, and could be fastened in position of highest tension, provided by a screw. Of course, at each roller end was placed one of such devices, each

1 within a depression, accessible from outside, through a groove, from which to fit the abrasive tape, through the same groove of the winch. The devices and the inherent grooves were placed in extremely and diametrically opposed positions, in order to unbalance as less as possible the roller. The abrading roller of the machines with a single roller, was provided with an annular peripheral hollow room, and in it was maintained a cooling liquid flow. Thus, every roller was fed with liquid and this rendered expensive and complex the same roller, the system cooling it, the whole unit. All these de-stabilizing factors: the weight of the roller, its unbalancing, the high heat conductivity, the inadequacy of the tenser, as agent or only in radial and/or tangential direction and once in a while, were expensive to eliminate, even if not completely eliminable. Thus the residual de- stabilization limited the R.P.M, which could not exceed about 1800 R.P.M.. Then the thermal expansion, and mechanical strain resulted in a bulking of abrasive tape, which centrifugally engaged, casually, with damage, the cloth to be abraded. The very high heating subjecting the rollers, particularly of machines with a single roller, for their high weight and thermal conductivity, rendered necessary an annular, cylindrical, concentric room close to the active surface to be cooled of the abrading roller. This compulsory room was provided to flow therethrough a cooling fluid, generally a liquid, which had to quietly flow in the roller room, without unbalancing it. Thus the roller was to be fed, while turning, and maintained filled with liquid, in order to avoid that possible empty accidental rooms could provide undue centrifugal unbalancing forces. This difficulty, non so light, increases heavily the cost of the roller and of the machine and in general disturb the room for equipments and for spare parts.

The invention as claimed is intended to remedy these drawbacks. The inventors, with ingenious perception, have conceived a process for making abrading rollers, spiral wound, for abrading machines provided with one or

more rollers, particularly for sheet materials, such as clothes and the like, which are made of very light material, so said composite, including carbon fibres provided by "Filament- Winding", using, as base of carbon fibre roving, fibres of carbon, with more thin wires and as pre-impregnant an epossidic resin. These rollers are provided, at each end, with a permanent fastening and tensioning elastic device, acting in both directions, adapted to bear the stress in operation, even when the speed is at least 1/3 as higher than that of conventional rollers. Essential fastening and tensioning member is a bladder which provides, directly a twofold result of fastening and distension and a third contemporary result of screw-drawing. This screw-drawing is obtained with a spiral shifting keying between an annular member, coating the extreme poles of the roller and a hub, with a spiral keying. The fastening device is, as unit and in the particulars substantially symmetric and centred and, it too, very light in order not to rise complicate problems of balancing. The bladder, is duly provided with an inlet and outlet valve, it is filled once in a while, for each application of abrasive tape. In accordance with a preferred embodiment of the present invention, when it is wanted, particularly on machines provided with a single roller, but in view of the reduced cost even on machines having more rollers, to cool them and in addition to obtain therefrom side effects, such as disposal and dross collecting, removing them from the asperities of the abrasive tape, a blower is provided, blowing a radial longitudinal air blade, placed upstream or downstream of the tangential line of contact with the fabric length to be worked. More particularly, having the machines a vertical attitude, with vertical feeding of the cloth to be worked, the nozzles of the air blades, extending all over the length of the rollers, are placed at the apex of each abrading roller, while the collecting container is single and placed at the base of the whole machine.

One way of carrying out the invention is described in detail below, with reference to drawings, which illustrate a specific embodiments, in which:

Fig. 1 is a perspective, exploded, view of one end, of an abrading roller, spiral wound, for abrading machines provided with one or more rollers, on whose details breaking have been made to show at different levels, the otherwise hidden particulars. Fig. 2 is a perspective view of the roller of fig. 1 assembled and in the attitude in which the end device is released i.e., in condition to receive, in a purposed groove, the end of the spiral of abrasive tape.

Fig. 3 is substantially a repetition of fig. 2 but in the attitude wherein in the purposed groove the end of the spiral of abrasive tape is stressed in three precise functional directions by a sole, particularly pneumatic, member.

Referring now to the figures of the drawings, an abrading roller, spiral wound, for abrading machines provided with one or more rollers, conventionally comprises a cylindrical body 3, provided at each end with a hub, in the drawings only one is shown, having two steps 4', 4". On the outer cylindrical surface of the body 3, is wound a spiral of tape 5, whose outer surface 5 ¹ is coated with abrasive material 5". Conventionally, the spiral wound, abrading rollers, for abrading machines provided with one or more rollers, include various devices 6, not shown, as it is shown in practice but only symbolically through the device of the present invention, whose function should be that of fastening and stretching the end of the abrasive tape 5, fastening it, with a radial centrifugal action and stretching it with a tangential action, in a direction coincident with the direction of the spiral with which the same spiral is to be wound. Moreover, conventional rollers are made of metallic material, more or less massive and thus heavy and difficult to manage, both in connection with the speed which cannot be increased and in connection with dynamic centring and inherent heating. Heating is particularly worrying in rollers of the machines with a single roller, which are provided with a layer 8, extending substantially all over the length of the roller 3, where they include an hollow space, not shown, of

ζ course of suitable dimensions, for the cooling liquid which, as said, must be fed while the roller 3 is turning.

In accordance with the present invention the abrading rollers 3, spiral wound, for abrading machines provided with one or more rollers, particularly for sheet materials, such as clothes and the like, are made, at least in the shell 30, of very light material, so said composite, particularly comprised with carbon fibres, provided with the so said "Filament- Winding", technology using as a base of the roving, particularly in carbon fibres, more wires and as pre-impregnant an epossidic resin. This shell 30 of very light material has in addition the advantage to have a heat transfer coefficient extremely low. It is so low that, to eliminate the superficial heat, produced at the level of surface 5" and flowing only negligibly in centripetal direction, it is sufficient to provide a blower, not shown. It blows, from a nozzle 7, an air longitudinal radial air blade 7', placed upstream or downstream of the tangential centripetal line of contact with the fabric length to be worked, not shown. In particular, having the machines a vertical attitude, with vertical feeding of the cloth to be worked, the nozzles 7, only one is shown, of the radial air blades 7', extending substantially all over the length of the rollers 3, are placed at the apex of each abrading roller, while the collecting container, not shown, is single and placed at the base of the whole machine. These rollers 3 are provided, at each end, with a permanent fastening and tensioning elastic device, acting in both directions, adapted to bear the stress in operation. With such process rollers is obtained that they may be driven to turn at speed at least 1/3 higher than highest speed obtainable with conventional rollers. Essential fastening and tensioning member is a bladder 9 which provides, directly a twofold result of fastening and distension and a third contemporary result of screw-drawing, which provides, directly a twofold result of fastening and distension as shown by the arrows 55, 55', as well as a contemporary result of screw-drawing, as shown by the arrow 55"

G which is obtained in combination with a spiral shiftable keying coupling, between an annular member 90, coating the extreme poles of the roller 3 and un hub 91, adjusted by a spiral keying 39. The fastening device is, as unit and in the particulars, substantially symmetric and centred and, it too, very light, in order not to rise complicate problems of balancing. The bladder 9, is duly provided with an inlet and outlet valve 93; it is filled once in a while, for each application of abrasive tape 5.

In accordance with a preferred embodiment of the present invention the bladder 9 is comprised by a pair of members 9 ^* and 9", made respectively of elastomeric material or the like: ring 9' which has an omega-like cross section, and is made of solid material and the ring 9", which is bored at interspaced constant intervals to receive the screws 09, provided in the cap 90, for keeping from inside the ring 9' fastened against the polar centripetal expansions 09' of the elastomeric section 9' of bladder, duly provided with inter-matching grooves (009, 009'). Of course, the bladder 9 is provided with a valve 93, preferably mounted in the ring 9", in order to be changeable without particular difficulties. From what explained heretofore the device operation should be evident, however a short description of it will be given hereafter. As regards as the assemblage of the members included in the exploded view of fig. 1, the drum 40, being provided to support an extremely light body shell 30 is it too maximally lightened being made completely hollow. To fasten it to the shell 30 it is sufficient a layer 8 of adhesive, e.g. of epossidic resin. Once the roller 3 is assembled, applying also the fastening elastic ring 44, and still keeping the machine stationary, after having developed flat the spiral of abrasive tape 5: an end of the same spiral is slipped between the cap inside 90 and the shell outside 30.

Of course, in these conditions, fig. 2, the bladder 9 must be substantially completely deflated. At this stage, air is inflated through the valve 93, with device 93'. The ideal pressure seems to be between two and four atmospheres.

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As shown in fig. 3 the pressure application provides force components, from which advantages can be obtained by the present invention: in fact a first centrifugal force 55, fastens the abrasive tape 5, between the bladder outer 9 and and the cap inner 90. Whereas, the axial expansion 55' of the bladder 9 provides the twofold effect of including an additional tangential component 55", suitable to stress the abrasive tape in the same direction of the spiral, as substantially dictated by the groove 39 and by the rod 95. Of course, the abrasive tape spiral 5 will result permanently self-stretched, even during operation, which will obviously correspond to the operation of the blower 7 and of inherent air blade 7'.