A rotary cutting tool with enhanced bump-off capability is disclosed. The cutting tool includes a tool shank having a pocket. A replaceable cutting head is at least partially disposed within the pocket of the tool shank with an interference fit. A coupling pin assembly is at least partially received within a bore of the tool shank. The coupling pin assembly comprises a sleeve member and a coupling pin at least partially disposed within the sleeve member. The sleeve member includes an upper portion and a lower portion having a non-circular cross-sectional shape with a bump-off surface. An actuation screw contacts the coupling pin assembly and causes the replaceable cutting head to move relative to the tool shank. The bump-off surface of the lower portion of the sleeve member extends radially outward with respect to the coupling pin by a distance, D, thereby providing enhanced bump-off capability.

A workholding apparatus (10) wherein a draw bar (22) effects chucking and de-chucking of a workpiece (W) and wherein un-seating of the workholding apparatus is effected by piston-like mechanisms (30) located in a machine spindle (2).

A method for releasing a screw connection between a core drilling device and a drill bit, wherein the screw connection is released by application of torque spikes to the drive shaft of the core drilling device, these torque spikes coming into effect when the drive shaft is driven counter to the actual drilling direction of the core drilling device. A core drilling device with which the proposed method can be carried out is also provided. To this end, the core drilling device includes a drive shaft to which torque spikes can be applied, wherein the drive shaft can be driven in a drilling direction and a second direction of rotation which is opposite to the drilling direction. A core drilling device, in which the reversal of a direction of rotation of a drive shaft of the core drilling device and application of torque spikes to the drive shaft are combined with one another such that, as a result of the combination of the reversal of the direction of rotation and torque spikes, a screw connection between the core drilling device and a drill bit can be released.

A rotary cutting tool with enhanced bump-off capability is disclosed. The cutting tool includes a tool shank having a pocket. A replaceable cutting head is at least partially disposed within the pocket of the tool shank with an interference fit. A coupling pin assembly is at least partially received within a bore of the tool shank. The coupling pin assembly comprises a sleeve member and a coupling pin at least partially disposed within the sleeve member. The sleeve member includes an upper portion and a lower portion having a non-circular cross-sectional shape with a bump-off surface. An actuation screw contacts the coupling pin assembly and causes the replaceable cutting head to move relative to the tool shank. The bump-off surface of the lower portion of the sleeve member extends radially outward with respect to the coupling pin by a distance, D, thereby providing enhanced bump-off capability.

A method for holding a spindle of a mobile power tool in order to allow an opening and/or a closing of a tool fitting by turning an operating part of the tool fitting relative to the spindle, where the spindle is rotationally coupled to an electric motor. The method includes detecting a rotation of the spindle and/or of the electric motor in a first direction while a setpoint angular velocity is zero and controlling the electric motor to generate a torque in a second direction which is opposite to the first direction.

A cutting tool holding mechanism for detachably holding a cutting tool includes: a collet chuck configured to clamp and unclamp the cutting tool; a piston disposed deeper on the proximal side of the spindle than the collet chuck and configured to urge the collet chuck by the pressure of a fluid supplied from the proximal side of the spindle in the direction from the proximal side toward the distal end side of the spindle so that the collet chuck unclamps the cutting tool; a spool valve provided in the piston and configured to open thanks to centrifugal force at the time when the spindle is turned, so as to supply the fluid fed from the spindle side to the cutting tool.

A workholding apparatus (10) wherein a draw bar (22) effects chucking and de-chucking of a workpiece (W) and wherein un-seating of the workholding apparatus is effected by piston-like mechanisms (30) located in a machine spindle (2).

A cutting tool holding mechanism for detachably holding a cutting tool includes: a collet chuck configured to clamp and unclamp the cutting tool; a piston disposed deeper on the proximal side of the spindle than the collet chuck and configured to urge the collet chuck by the pressure of a fluid supplied from the proximal side of the spindle in the direction from the proximal side toward the distal end side of the spindle so that the collet chuck unclamps the cutting tool; a spool valve provided in the piston and configured to open thanks to centrifugal force at the time when the spindle is turned, so as to supply the fluid fed from the spindle side to the cutting tool.

An arrangement for machining workpieces includes a machining tool (1) having a cutting edge region (3) and a shank (30), the shank (30) having a conical shank region (5) and a receiving region (4) arranged adjacent to the shank region (5), a tool extension (2) having a conical receiving region (21), the conical shank region (5) and the conical receiving region (21) being designed complementary to each other such that the machining tool (1) is held between the conical shank region (5) and the conical receiving region (21) exclusively by means of a force-fitting connection in the tool extension (2), a tool holding device (15) for receiving the tool extension (2). The tool holding device (15) is adapted to be connected to a rotatable spindle of a machine tool. The cutting edge region (3) has a maximum diameter D1 in a plane E perpendicular to a center axis X.

A chuck device for holding a plate material workpiece supplied to a machine tool without deforming the workpiece is provided. A housing has a workpiece contact surface arranged to face workpiece holding claws, and when holding of a workpiece is released, a plurality of rods integrally swings so that the workpiece holding claws are moved away from the workpiece contact surface of the housing and moved away from each other, and when holding the workpiece, after the plurality of rods integrally swing so that the workpiece holding claws are brought close to the workpiece contact surface of the housing and brought close to each other, the plurality of rods moves integrally in parallel with the forward/backward moving direction of a drive body to bring the workpiece holding claws into contact with the workpiece.