Handheld power tool and control method
AssigneeHilti Aktiengesellschaft
InventorsErwin Manschitz, Walter Wissmach
Life of this patent
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Abstract
A handheld power tool has a tool socket (2) to hold a tool (4) along a working axis (11), a motor (5) and a slip clutch (21) having a number of blocking elements. A sensor (27) serves to record a measured signal (28) as the measure of vibrations inside the handheld power tool (1). A band-pass filter (29) has a pass range in which a frequency lies that is equal to the product of the rotational speed of the wheel (22) on the drive side and the number N of blocking elements (24). The measured signal (28) filtered by the band-pass filter (29) is fed to an evaluation unit (30). When the filtered measured signal (28) exceeds a limit value, the evaluation unit (30) reduces the rotational speed of the motor (5).
Claims5
A handheld power tool comprising:
- a tool socket to hold a tool along a working axis;
- a motor;
- a slip clutch having a drive side wheel on a drive side and a driven side wheel on a driven side as well as a number (N) of blocking elements arranged between the drive side wheel and the driven side wheel, the blocking elements movable relative to one wheel of the drive side and driven side wheels and the blocking elements held engaged with the one wheel by a spring force, in order to transmit a torque from the drive side wheel to the driven side wheel and in order to interrupt the transmission of torque when a torque exceeding a threshold value is present;
- a sensor serving to record a measured signal indicating movements of the handheld power tool;
- a band-pass filter in whose pass range a product of the rotational speed of the drive side wheel and the number (N) of blocking elements lies,
- an evaluation unit, the measured signal filtered by the band-pass filter being fed to the evaluation unit, the evaluation unit reducing a rotational speed of the motor in response to the filtered measured signal exceeding a limit value.
Dependencies are inferred from the claim text.