Abstract: In an annular saw, that is to say a circular saw with an annular saw blade, the saw blade is adapted to rotate about an imaginary center axis by being driven via a drive shaft which is parallel to the center axis and has a fulcrum between the annular saw blade and its center. Mounted on the drive shaft (27) are two drive rollers (25, 26), of which the adjacent surfaces (41, 42) are bevelled at a certain bevel angle so that the rollers comprise drive surfaces which, between them, form a wedge-shaped groove (40). The two lateral surfaces of the saw blade (8) are bevelled in a corresponding manner within a region (13) close to the inner edge (15) of the saw blade, the bevel angle being the same as for the drive rollers, the bevelled edge portion of the annular saw blade being clamped between the bevelled drive surfaces of the drive rollers in the wedge-shaped groove.

Abstract: A circular saw blade of centerless type which has a sawing depth greater than the radius of the circle, comprises an annular blade and at least one central disc provided inside the annular blade. The central disc contains at least one conduit or passage for a fluid, e.g. for a coolant or a flushing agent to the part of the disc which lies within the region of the maximum sawing depth.

Abstract: Apparatus for rotating an annular or ring shape tool such as a saw blade or grinding wheel. The tool is rotated by a power driven drive roller acting on a face of the ting tool. A rigid arm supports guide rollers which in turn support the tool. The guide rollers have grooves that engage the inner periphery of the ring tool. The inner periphery of the ring tool may define a tapered tongue with a rounded edge that fits into complimentary shaped grooves in the guide rollers. Fixed and movable U-shape guards are provided to shield substantially all of the ring tool.

Abstract: A portable power tool having an annular ring tool, such as a saw blade or grinding wheel, driven on its periphery by a power unit. A ring tool housing carries the ring tool and is mounted to the power unit, the latter having a drive shaft roller which frictionally engages one surface of the ring tool. Ring tool guide bearings and ring tool support bearings oppose and cooperate with the drive roller to retain the ring tool within the housing during its rotation.The driven shaft axis is canted at an angle extending beyond the center of the ring tool or toward the working side of the ring tool to counteract the torque forces produced by the working operation. Means are also provided to vary the drive roller pressure on the ring tool to balance the torque or, alternatively, to vary the drive shaft axis angle to balance the torque thereby producing dynamic stability during the working operation regardless of work piece resistance.