Abstract: A hollow spindle (10) comprises a collet (20) at one end and behind the same and spaced from each other two guide sleeves (50,52) for the work bar (W). The rear guide sleeve (52) being the most remote from the collet (20) is axially displaceable in a direction toward the collet (20) against the resistance of a spring (58) and has an abutment face (82) remote from the collet (20) for a stock feeder (70). Upon advanced use of the work bar (W) the stock feeder (70) hits the abutment face (82) of the rear guide sleeve (52), pushing the same forwardly as the work bar (W) continues to be used up and advanced. By virtue of this arrangement the work bar (W) is guided in vibrationless manner and also the stock feeder (70) is kept largely without vibrating by its abutment against the rear guide sleeve (52).

Abstract: The tool holder (14) includes a tool holder head (30) having a planar abutment face (38) and a tool holder shaft (40) extending at right angles away from the abutment face (38) and adapted to be clamped in a receiving bore (44) of a tool support (10). A gripper plate (50) lies in abutment against the abutment face (38) all around the tool holder shaft (40) and has two gripping faces (54 and 56) inclined with respect to each other at one side of the tool holder shaft (40) and another gripping face (58) at the opposite side inclined with respect to said two gripping faces. The gripper plate (50) is adapted to be grasped in such manner by a gripper (20) that the tool holder (14) will adopt an exactly predetermined position with respect to the gripper (20), regardless of how the tool holder is designed otherwise.

Abstract: A sensor pin carrier (34) is disposed in a housing (20) and rests on a support member (26) by way of a bearing which is arranged all around a central longitudinal axis (40), and the sensor pin carrier is designed for securing at least one sensor pin (38). The sensor pin carrier (34) is attached in the middle of an elastic disc (30) disposed vertically with respect to the longitudinal axis (40) and secured at its outer edge in the housing (20). At least one electric switch (56) is associated with the sensor pin carrier (34) to generate a signal upon deflections of the sensor pin (38).

Abstract: An improvement in bar feeding mechanisms is disclosed. The bar feeding mechanism which comprises a plurality of roller assemblies disposed on a frame has an adjustable stop for limiting the movement of the rollers toward the axis of the bar being fed. The mechanism is especially advantageous for irregularly shaped bars.