Compressed air-driven tool
AssigneeSUHNER Schweiz AG
InventorsStefan Wiedemeier, Stefan Ineichen
Life of this patent
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Abstract
A compressed air-driven tool having an electromagnetically operated control element (27) for controlling a pneumatic control circuit in order to maintain a load-independent torque at a constant rotational speed. The tool includes a principal valve (5), which arranged in a drive housing (1) in a manner displaceable by the supplied compressed air against the force of a helical spring (13), and a generator (43), which is mounted on the shaft (49) of a turbine wheel (51). The rotational speed of the shaft (49) is measured with a speed sensor (75) and the supply of compressed air to the principal valve (5) is controlled in the event of a drop in rotational speed as a consequence of a load.
Claims14
A method for regulating a rotational speed of an output shaft (49) at a tool which is driven with compressed air, the method comprising:
- using a generator (43) driven by the compressed air, in the tool, and generating an alternating-current voltage;
- activating an electromagnetic regulating element (27) using the alternating-current voltage by which a quantity of air for the drive of a turbine wheel (51) on the output shaft (49) is regulated,
- converting the alternating-current voltage into a direct-current voltage in a rectifier (55),
- maintaining the direct-current voltage constant using a voltage regulator (57) independently of the rotational speed of the output shaft (49),
- feeding a microcontroller (37) with the constant direct-current voltage, measuring a present value of the rotational speed of the output shaft (49) using a rotational speed sensor (75), and
- the microcontroller (37) regulating, by way of the electromagnetically driven regulating valve (27), the quantity of air supplied to the turbine wheel (51) and keeping a set predefined rotational speed of the shaft (49) constant.
A compressed air-driven tool comprising:
- a drive housing (1) which includes a turbine wheel (51) that drives an output shaft (49),
- an air inlet duct (3) for compressed air, a waste-air duct (73),
- a generator (43) inserted in a supply air path for the compressed air that is adapted to generate an electrical alternating-current voltage,
- a rectifier (55) that is configured to convert the electrical alternating-current voltage to a direct-current voltage,
- a microcontroller (37),
- a rotational speed sensor for the output shaft, and
- a voltage regulator configured to generate a constant output voltage, which is independent of a rotational speed of the shaft (49), for operation of the microcontroller (37) which is configured to control a control element (27) for the actuation of a main valve (5) based on measurement data of the rotational speed sensor (75) for the output shaft (49).
Dependencies are inferred from the claim text.