Abstract: The invention relates to a device for monitoring the contact of a workpiece (1) or tool on a spindle (2) of a machine tool, which device has a contact surface (3) for the workpiece (1) or tool. At least one measurement nozzle (4) is arranged in the region of the contact surface in order to produce a fluid flow directed away from the contact surface (3). Upstream of the measurement nozzle, the fluid flow is conducted through a vacuum nozzle, which can comprise a jet nozzle (7c) and a collector nozzle (7b). When the fluid medium flows through the vacuum nozzle, the vacuum nozzle produces a negative pressure in a negative pressure chamber (9c). A pressure sensor (6) or pressure switch senses a measurement pressure (p3) in the negative pressure chamber.

Abstract: The invention relates to a device for monitoring the contact of a workpiece (1) or tool on a spindle (2) of a machine tool, which device has a contact surface (3) for the workpiece (1) or tool. At least one measurement nozzle (4) is arranged in the region of the contact surface in order to produce a fluid flow directed away from the contact surface (3). Upstream of the measurement nozzle, the fluid flow is conducted through a vacuum nozzle, which can comprise a jet nozzle (7c) and a collector nozzle (7b). When the fluid medium flows through the vacuum nozzle, the vacuum nozzle produces a negative pressure in a negative pressure chamber (9c). A pressure sensor (6) or pressure switch senses a measurement pressure (p3) in the negative pressure chamber.