Safety clutch for electrical hand-held tool
AssigneeHilti Aktiengesellschaft
InventorsFerdinand Kristen, Hans-Werner Bongers-Ambrosius, Peter Hellmann
Life of this patent
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Abstract
A safety clutch for an electric hand-held tool and including a rotor (8), an anchor disc (9) frictionally engageable with the rotor (8) for transmitting a torque there-between, a stationary axial stop (13) for limiting the air gap (s) between the rotor and the anchor disc and engageable by the anchor disc under an axial reserved pre-stress applied to the anchor disc (g); and a stationary electromagnetic coil (11) provided on a side of the rotor (8) remote from the anchor disc (9) and coaxial with the rotor (8) for generating a rotationally symmetrical magnetic flux (φ) for attracting of the anchor disc (g) to magnetic poles (12a, 12b) associated with the rotor (8).
Claims14
A safety clutch for an electric hand-held tool, comprising a rotor (8);
- an anchor disc (9) frictionally engageable with the rotor (8) for transmitting a torque therebetween and spaced from the rotor (8) by an air gap (S) in a disengagement position of the anchor disc (9);
- a stationary axial stop (13) for limiting the air gap (S) and engageable by the anchor disc under an axial reserved prestress applied for the anchor disc, and fixedly securable in a tool housing (3);
- and a stationary electromagnetic coil (11) likewise fixedly securable in the tool housing (3) and provided on a side of the rotor (8) remote from the anchor disc (9) and coaxial with the rotor (8) for generating a rotationally symmetrical magnetic flux (φ) for attracting of the anchor disc (9) to magnetic poles (12a, 12b) associated with the rotor (8) to provide for a frictional engagement of the anchor disc (9) with the rotor (8).
An electric hand-held tool, comprising a housing (3);
- a percussion mechanism (4) located in the housing (3);
- an electric motor (5) for driving the percussion mechanism (4);
- gear means (6) for transmitting torque to the percussion mechanism (4);
- and a safety clutch (7) arranged in power flow from the electric motor (5) to the gear means (6), the safety clutch (7) having a rotor (8), an anchor disc (9) frictionally engageable with the rotor (9) for transmitting a torque therebetween and spaced from the rotor (8) by an air gap (S) in a disengagement position of the anchor disc (9), a stationary axial stop (13) for limiting the air gap (S), engageable by the anchor disc (9) under an axial reserved prestress applied to the anchor disc (9) and fixedly securable in the housing (3), and a stationary electromagnetic coil (11) likewise fixedly securable in the housing (3), and provided on a side of the rotor (8) remote from the anchor disc (9) and coaxial with the rotor (8) for generating a rotationally symmetrical magnetic flux (φ) for attracting of the anchor disc (9) to magnetic poles (12a, 12b) associated with the rotor (8) to provide for a frictional engagement of the anchor disc (9) with the rotor (8).
Dependencies are inferred from the claim text.