One object is to improve the uniformity of polishing of a substrate. The present application discloses, as one embodiment, a substrate polishing device for a quadrilateral-shaped substrate, the device including: a surface plate; a substrate support mechanism that is attached to the surface plate and that supports the substrate; a polishing head mechanism for attaching a polishing pad, the polishing head mechanism opposing the surface plate; and an orbital drive mechanism for orbitally driving the polishing head mechanism. The substrate support mechanism includes: a base plate; a plate flow passage provided to the base plate; and a plurality of substrate support chambers that are connected to the plate flow passage, wherein each substrate support chamber independently applies a vertical direction force to the substrate, and the vertical direction force applied to the substrate corresponds to an internal pressure of the substrate support chamber.

One object is to improve the uniformity of polishing of a substrate. The present application discloses, as one embodiment, a substrate polishing device for a quadrilateral-shaped substrate, the device including: a surface plate; a substrate support mechanism that is attached to the surface plate and that supports the substrate; a polishing head mechanism for attaching a polishing pad, the polishing head mechanism opposing the surface plate; and an orbital drive mechanism for orbitally driving the polishing head mechanism. The substrate support mechanism includes: a base plate; a plate flow passage provided to the base plate; and a plurality of substrate support chambers that are connected to the plate flow passage, wherein each substrate support chamber independently applies a vertical direction force to the substrate, and the vertical direction force applied to the substrate corresponds to an internal pressure of the substrate support chamber.

An easy-detachable grinding device for a cement walk-behind trowel machine comprises a plurality of installing units arranged on a seat which is installed with the central disk and the outer rotary disks. In use, it is only needed to buckle the installing units to the grinding knives of a power source of a cement walk-behind trowel machine so that the central disk and the outer rotary disks are assembled to the cement walk behind trowel machine. The original grinding knives are unnecessary to be detached from the cement walk behind trowel machine. Furthermore the grinding device can be detached easily as it is not used, while the original used grinding knives can be used again. No more vehicle is needed. Outer rotary disks are arranged on the periphery of the central disk so as to have a large grinding area.

An easy-detachable grinding device for a cement walk-behind trowel machine comprises a plurality of installing units arranged on a seat which is installed with the central disk and the outer rotary disks. In use, it is only needed to buckle the installing units to the grinding knives of a power source of a cement walk-behind trowel machine so that the central disk and the outer rotary disks are assembled to the cement walk behind trowel machine. The original grinding knives are unnecessary to be detached from the cement walk behind trowel machine. Furthermore the grinding device can be detached easily as it is not used, while the original used grinding knives can be used again. No more vehicle is needed. Outer rotary disks are arranged on the periphery of the central disk so as to have a large grinding area.

A grinding method includes a first grinding step of executing grinding feed of a rough grinding unit and grinding the workpiece to a predetermined thickness while supplying grinding water with a first grinding water amount that allows suppression of wear of grinding abrasive stones and a second grinding step of, after executing the first grinding step, promoting dressing of the grinding abrasive stones to prepare for processing of the next workpiece through executing grinding feed of the rough grinding unit and grinding the workpiece to the finished thickness while supplying the grinding water with a second grinding water amount that increases wear of the grinding abrasive stones and promotes self-sharpening through reduction relative to the first grinding water amount.

A grinding method includes a first grinding step of executing grinding feed of a rough grinding unit and grinding the workpiece to a predetermined thickness while supplying grinding water with a first grinding water amount that allows suppression of wear of grinding abrasive stones and a second grinding step of, after executing the first grinding step, promoting dressing of the grinding abrasive stones to prepare for processing of the next workpiece through executing grinding feed of the rough grinding unit and grinding the workpiece to the finished thickness while supplying the grinding water with a second grinding water amount that increases wear of the grinding abrasive stones and promotes self-sharpening through reduction relative to the first grinding water amount.

A portable power tool includes an electric motor having a motor shaft, an output shaft arranged in parallel to the motor shaft and configured to be driven by rotation of the motor shaft, a tool accessory operably connected to the output shaft and configured to undergo an orbital and/or rotational motion in response to rotation of the output shaft, a first bearing that rotatably supports the output shaft, and a second bearing that rotatably supports the output shaft and is arranged closer to the tool accessory than the first bearing in an axial direction in which the output shaft extends. The first and second bearings are arranged at positions that do not overlap with a radially outermost one of components of the electric motor when viewed in a shaft arrangement direction in which the motor shaft and the output shaft are arranged in parallel.

A portable power tool includes an electric motor having a motor shaft, an output shaft arranged in parallel to the motor shaft and configured to be driven by rotation of the motor shaft, a tool accessory operably connected to the output shaft and configured to undergo an orbital and/or rotational motion in response to rotation of the output shaft, a first bearing that rotatably supports the output shaft, and a second bearing that rotatably supports the output shaft and is arranged closer to the tool accessory than the first bearing in an axial direction in which the output shaft extends. The first and second bearings are arranged at positions that do not overlap with a radially outermost one of components of the electric motor when viewed in a shaft arrangement direction in which the motor shaft and the output shaft are arranged in parallel.

The present invention relates to a device (14) for sanding floor areas, the device comprising a frame, a steering, a motor which is provided to said frame, a subframe (13) rotatably coupled with said motor, said subframe being centrally provided with an adapter (7) along the lower side, a sanding frame (1), said sanding frame being centrally provided with a receiver (2) along the upper side, said receiver receiving said adapter, and at least one holder (5) for sanding elements, said holder being provided along the lower side of said sanding frame and being suitable for the attachment of sanding elements (15). In particular, the subframe is freely supported by the sanding frame, via said adapter and receiver, said adapter and receiver being rotationally coupled. In other aspects, the invention relates to a sanding frame, a sanding element and a method for sanding floor areas, as well as a floor area obtained by application of said method.

A tool driver for a power trowel, the tool driver comprising a combination of a magnetic fastening arrangement and a friction based fastening arrangement for releasably holding an abrasive tool to the tool driver, wherein the magnetic fastening arrangement is configured symmetrically around a rotational center of the tool driver, wherein the friction based fastening arrangement is adapted to provide increased shear strength during abrasive operation of the tool, and wherein the magnetic fastening arrangement is adapted to provide increased pull strength during lifting of the tool driver.