A method is disclosed for treating or maintaining a hard surface comprising a stone or stone-like material, the method comprising treatment of the surface with a flexible pad, in the presence of abrasive particles, bonded to the pad, on a contact surface between the pad and the hard surface, wherein the abrasive particles comprise diamond particles, and the treatment is performed in the absence of an effective amount of crystallization agent on the contact surface. The treatment is performed on a substantially regular basis, such as daily, weekly or monthly, and the treatment is performed using a pad comprising an open, lofty, three dimensional non-woven webs of fibers. A tool for use in the method is also provided, as well as a floor-surfacing machine comprising such a tool and a method for manufacturing such a tool. Furthermore, methods for treating or maintaining hard, smooth surfaces such as wood, polymer material, lacquer, linoleum, gelcoat, glass and automotive enamel are disclosed.

Dynamic regulation of contact pressures in a blade sharpening system is provided. An example multiphase grinding wheel has a grinding face with one or more abrasive concentric rings for sharpening the cutting blade of the log saw machine, and one or more padded concentric rings consisting of fiber padding. Sharpening with the multiphase grinding wheel improves cut quality, increases blade life, removes glues and varnishes from the cutting blade, reduces blade deformation, and hones the edge of the cutting blade. A pneumatic tensioning system uses air bladders to apply dynamic cushioning and processor-controlled contact pressure between the grinding wheels and the cutting blade during sharpening. The fiber-padded grinding wheels and the air bladder tensioner provide improved sharpness of the cutting blade and longer life for the mechanical components.

In an automatic wet sanding apparatus including a disc and a cushion pad, a disc center hole is formed at a central portion of the disc and a pad center hole is formed at a central portion of the cushion pad. Water having been supplied to an introduction space inside a skirt is stirred as an eccentric head rotates eccentrically and thereby pushed out toward a painted surface via the disc center hole and the pad center hole with enhanced pressure. Thus, sanding dust resulting from automatic wet sanding can be washed away toward an outer circumferential side by the water that is pushed out toward the outer circumferential side, so that the likelihood of clogging due to sanding dust can be reduced and high sanding efficiency can be maintained.

A polishing pad is provided. The polishing pad comprises a polishing layer and a metal-containing layer. The polishing layer has a polishing surface and a backside surface opposite to each other, wherein the backside surface has a plurality of cavities. The metal-containing layer is disposed on the backside surface of the polishing layer and fills into the cavities, wherein a first contact area is between the metal-containing layer and the backside surface of the polishing layer, and the first contact area is larger than the orthogonal projection area of the polishing layer.

An air cylinder that changes the posture of an automatic wet sanding unit main body having sandpaper mounted thereon is provided with a guide rod, and an outer circumferential surface of the guide rod has grooves that extend along a shaft centerline of the guide rod and have an arc-shaped cross-section. Balls are interposed between a bottom of each groove and an inner surface of a bush that is provided inside the air cylinder. Thus, it is possible to make two objects compatible with each other: to achieve high-accuracy automatic wet sanding by enhancing the adaptability of the sandpaper to the shape of a painted surface through a reduction of the diameter of the piston rod; and to enhance the durability of the automatic wet sanding apparatus.

In an automatic wet sanding apparatus including a paper peeling unit that has a clamping shaft and a clamping hook, an inclination angle of a leading end surface of the clamping hook is equal to an inclination angle of an outer circumferential surface of a cushion pad at the start of a paper peeling step. Thus, the leading end surface of the clamping hook comes into contact with an outer circumferential end of a disc at the same time as coming into contact with the outer circumferential surface of the cushion pad, so that the cushion pad is less likely to get caught due to deformation of the outer circumferential surface and its peripheral part of the cushion pad. It is therefore possible to appropriately remove the sandpaper from the cushion pad and stably perform the task of removing the sandpaper.

A grouting pan assembly includes a reinforcement ring. In another aspect, a grouting pan includes a substantially planar bottom surface and a curved sidewall surrounding the bottom surface. In a further embodiment, a grouting pan assembly includes a grouting pan having a post or mechanical fastener extending from a backside thereof for attachment to a reinforcing ring or layer.

A polishing tool with a carrier comprising a polishing surface on which a polishing paste is applied at least in some areas, wherein the polishing surface consists of a nonwoven fabric, the polishing paste is in a solid state at room temperature and is applied on the polishing surface to be covered in an amount of 0.08 g/cm.sup.2 to 0.30 g/cm.sup.2.

Dynamic regulation of contact pressures in a blade sharpening system is provided. An example multiphase grinding wheel has a grinding face with one or more abrasive concentric rings for sharpening the cutting blade of the log saw machine, and one or more padded concentric rings consisting of fiber padding. Sharpening with the multiphase grinding wheel improves cut quality, increases blade life, removes glues and varnishes from the cutting blade, reduces blade deformation, and hones the edge of the cutting blade. A pneumatic tensioning system uses air bladders to apply dynamic cushioning and processor-controlled contact pressure between the grinding wheels and the cutting blade during sharpening. The fiber-padded grinding wheels and the air bladder tensioner provide improved sharpness of the cutting blade and longer life for the mechanical components.

The invention relates to a polishing disc for a tool for fine processing optically active surfaces on spectacle lenses, having a main body which has a central axis and to which an intermediate layer that is softer than the main body and is made of a resilient material is secured, a polishing medium carrier resting on the intermediate layer. The intermediate layer has at least two regions with different degrees of hardness, said regions being arranged one behind the other in the direction of the central axis of the main body. The intermediate layer region adjoining the main part is softer than the intermediate layer region on which the polishing medium carrier rests.