The invention relates to a sanding wheel com¬ prising a wheel provided with a hub, brushes arranged on the periphery of the wheel and being comprised of separate units, as well as sanding papers or cloths projecting from between the brush units substantially radially past the brushes.

Such sanding wheels are very common and are used especially in the furniture industry. As an example of the prior art, the device disclosed in U.S. Patent No. 2,430,099 may be cited. The disadvantage of this known device is the complexity of the positioning of the sand¬ ing paper or cloth. In said construction, several groups have been formed of the sanding papers or cloths, said groups being mounted on fixing axles uniformly axially spaced about the axis of the wheel. This system is in practice cumbersome, as the wheel must be partly dis¬ assembled when the papers are replaced, and, moreover, each paper or cloth must be individually slipped from between the brushes. What is more, the construction of the device is rather complicated and expensive.

As another example, the sanding wheel disclosed in Finnish Patent No. 23,929 may be cited. Also this construction has the disadvantage of the difficulty in replacing the sanding papers or cloths. In this construc¬ tion, separate strips of sanding paper or cloth are utilized, which are secured in position by means of locking bars movable by centrifugal force. Each paper or cloth must in each case be individually slipped through a narrow slot, and thus also this device is not advan¬ tageous in practice.

As a third example of the prior art, the sanding wheel disclosed in Swedish Patent No. 222,389 may further be cited. In this known construction, the sanding papers or cloths are arranged on several separate rolls which

are mounted on separate axles on the wheel. The supply¬ ing of paper or cloth from each separate roll is effected by means of a separate feed device. The disadvantage of this known device is the complexity thereof, as a result of which the working reliability is not good. Owing to the construction, also the maintenance costs are rela¬ tively high.

The object of this invention is to achieve a sanding wheel which does not have the disadvantages of the previously known constructions.

More precisely, the invention is characterized by that the sanding papers or cloths are assembled in a pile staggered in the longitudinal direction of said papers or cloths, in which pile each sanding paper or cloth is fastened at one end thereof only to the next sanding paper or cloth, that the pile is secured at the joined end thereof to the hub and wound about the hub, and that the brush units are arranged, when the pile of sanding papers or cloths is replaced, to be positioned subsequent to the winding of the pile of sanding papers or cloths about the wheel in such a manner that the free outer end of each sanding paper or cloth is arranged to project from adjacent the brush unit last positioned to outside the wheel prior to the mounting of the next brush unit bearing upon the aforesaid positioned brush unit. The advantage of the sanding wheel according to the invention is, above all, the simplicity thereof. Owing to the construction of this sanding wheel, the manufacturing costs thereof are low. Another advantage of the invention is its economy in use, as the sanding paper or cloth can be well utilized, i.e., the waste percentage is small. The number of replacements of the paper or cloth is also diminished significantly, and thus the replacements may be adjusted in accordance with the work. The actual replacement operation is very simple and quick, and thus the degree of utility of the device

is considerably better than with the known devices.

The following is a more detailed description of the invention by means of a preferred embodiment illus¬ trated in the accompanying drawing, wherein Figure 1 is a side view of a sanding wheel according to the invention in a schematic sectional drawing.

Figure 2 shows the sanding wheel of Figure 1 viewed from the direction of the rotation axis, Figure 3 shows schematically how the sanding paper or cloth is spanned about the hub.

Figure 4 is a front and side view of the locking means, and

Figure 5 is a side view of another embodiment of the invention in a schematic sectional drawing.

In the Figures, the axle is denoted by the refe¬ rence number 1 and the hub mounted thereon by the general reference number 2. The hub may, for example, consist of a tubular part 3 and flanges 4. The sanding wheel additionally comprises support flanges 5, where¬ upon the brush units 6 are mounted to rest. Figure 1 shows merely two brush units and Figure 2 three respec¬ tively. However, it is apparent that there are brush units on the outer periphery of the support flanges 5 uniformly over the entire periphery. Figure 1 additional¬ ly schematically shows means 7 by which the hub 2 can be releasably secured to the axle, whereby it rotates along with the axle or may, if desired, rotate freely whilst the axle 1 remains stationary. For clarity, the sanding paper or cloth is not shown in Figure 1 , said paper or cloth being shown e.g. in Figure 2 by the reference number 8.

The sanding paper or cloth 8 is mounted on the sanding wheel according to the invention in the following manner. Firstly, a longitudinally staggered pile has been formed of the sanding papers or cloths 8. This pile has

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been formed in such a manner that one end of each paper or cloth has been fastened only to the next paper or cloth. The manner of fastening can clearly be seen from Figure 3. The staggering of the papers or cloths 8 has been determined on the basis of the circuit of the hub and the number of the papers or cloths. The securing of the pile to the wheel is made prior to the fixing of the brush units 6 e.g. in the following manner. For the securing e.g. the locking means 9 shown in Figure 4 and having a slot 10 is used. The size of the slot 10 has been made such that two sanding papers or cloths may pass therethrough simultaneously. The locking means 9 is firstly slipped through the last paper in the pile, whereafter the first paper is wound about the hub and also slipped through slot 10 in the locking means 9

(Figure 3). After this, the first paper is pulled at in the direction of the arrow N, whereat the entire pile begins to become wound about the hub 2. It shall be noted that Figure 2 for clarity shows merely the hub and the pile of paper or cloth. Neither have but a few sanding papers or cloths been illustrated, in reality there are considerably more.The final securing to the hub is done by placing the ends of the locking means 9 in grooves 11 made on the flanges 4 of the hub. By pulling the first paper further in the direction of the arrow N and by shifting the locking means 9, when necessary, in the groove towards the surface of the hub tube, the entire pile can be secured to the hub 2. The entire pile may be wound about the hub simply by rotating the wheel until the free ends of the sanding papers or cloths are wound up on the hub 2.

The fastening of the brushes 6 comprised of sepa¬ rate units is carried out in the following manner. For the fixing there is used a turnable ring member 12 mounted on the outer periphery of one of the support flanges 5. The ring member 12 is provided with an axial opening 13

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through which one end of the brush unit 6 can pass radial¬ ly. The brushes are positioned in the following manner. One end of the first brush unit 6 (in Figure 1, the left end) is placed in the notch 14 of one support flange 5 and the other (right) end is lowered radially (in Figure 1), vertically downwards) to be sustained by the other support flange 5. Next, the end of the topmost sanding paper or cloth 8 is taken from upon the hub and lifted up to be adjacent the positioned brush unit. Thereafter, the ring member 12 is turned slightly and the next brush unit is positioned in a manner similar to the first. Subsequently, another sanding paper or cloth 8 is lifted up to be adjacent the brush unit last positioned, etc. This is continued until all of the brush units 6 are positioned, whereby also all of the sanding papers or cloths are placed to pass between the brush units (Fig¬ ure 2). The form of the brush units has been selected in such a manner that they bear upon one another, wherefore they need not be separately fixed to one another or to the support flanges. The ring member 12 is finally shift¬ ed in such a position that no brush unit may climb up¬ wards through the opening 13, and locked in this posi¬ tion. Naturally, the brush units are provided with a recess 15, forming together with the next brush unit 6 an aperture for the sanding paper or cloth 8. After the fixing of the brushes, the wheel is ready for use.

The shifting of the sanding paper or cloth 8 as a consequence of wear may in the construction of the in¬ vention be carried out in the following manner. The means 7, which may consist e.g. of a screw by means of which e.g. a journal or equivalent can be squeezed against the flange of the hub, is unbolted, as a result of which the hub 2 is freely rotatable. Thereafter, a free end of one of the sanding papers or cloths is pulled at, which makes the hub to rotate with respect to the axle and all ends of said papers or cloths to be shifted

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simultaneously radially outwards. Subsequently, the hub 2 is locked in the new position, and the wheel is ready for use. Thus the wheel need not be taken apart when a paper is shifted. The replacing of the paper or cloth 8 is carried out by releasing the brush units 6 and positioning a new sanding paper or cloth 8 in the manner afore stated.

Figure 5 shows a preferred embodiment of the invention which may be used e.g. in machinery having old wheels.Figure 5 carries similar reference numbers for parts corresponding to e.g. the respective parts in the construction of Figure 1.

The greatest difference to the construction of Figure 1 is that the hub 2 has been made demountable, so that the entire hub may be removed when the pile of papers is replaced. Thereby it is possible to use even an entirely new hub whereupon a pile of sanding papers or cloths has already been mounted. In the construction of Figure 5, the demounting of the hub is effected by unscrewing nut 16, whereby the entire head is loosened and the hub may be removed from the axle 1. The shifting of the sanding paper or cloth is carried out by loose¬ ning nut 16, whereby the hub can rotate on the axle 1. The hub is locked in position by tightening nut 16. The location of the flanges 5 in relation to one another may be secured e.g. by studs 17. The fastening of the brushes is carried out in a manner fully similar to that for the construction of Figure 1.

The above described embodiment is naturally not intended to limit the invention, wherefore the invention may be modified in many different ways within the scope of the appended claims. For example, the securing means 7 may be of any type, and the securing of the paper or cloth may be carried out also in ways other than by means of groove 11. Moreover, it is apparent that the form of the brush units 6 may vary, e.g. necessary

roundings and chamferings may be done as required. Also the structural details of the wheel may vary considerably within the scope of the claims.The sand¬ ing papers or cloths may be fastened together by any known means, e.g. by sewing or glueing, etc.

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