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AssigneeBlack & Decker Inc.
InventorsMichael Stirm, Norbert Hahn, Martin Lauterwald, Achim Jung, Stefan Gensmann, Robert Usselman, Robert Bradus
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A hand held motor driven electrically powered tool, in particular a rotary hammer, comprising a spindle (40) for rotatingly driving a tool or bit (68), a spindle rotary drive train (14, 5, 10) for rotatingly driving the spindle (40) and an arrangement for detecting blocking events (16, 17). Blocking events occur when the tool or bit of the tool become rotationally fixed in the material being bored in which case the rotary drive on the spindle from the motor causes the tool housing to rotate in a user's grip. According to a first aspect of the invention an overload clutch (14) is provided in the spindle rotary drive train for transmitting rotary drive to the spindle below a predetermined torque and slipping above the predetermined torque arranged such that the overload clutch cuts off rotary drive to the spindle, for example by reducing the predetermined torque at which the overload clutch (14) slips when a blocking event is detected so as to cut off rotary drive to the spindle in response to a blocking event being detected. According to a second aspect of the invention there is provided a mode change mechanism (45, 47, 49, 43) for selectively disengaging a clutch (10, 7) so as to cut off the rotary drive to the spindle (40) and the clutch is disengaged when a blocking event is detected so as to cut off rotary drive to the spindle in response to a blocking event being detected.
An overload clutch assembly for a power tool having a spindle for rotatingly driving a working member of the tool and a spindle rotary drive train for rotatingly driving the spindle, the assembly comprising:
An assembly according to any one of the preceding claims, further comprising at least one detector device for detecting blocking of a working member of the tool, wherein at least one said actuator device is adapted to switch said overload clutch to a said second mode thereof in response to detection of blocking of said working member.
An assembly according to any one of the preceding claims, wherein at least one said actuator device is adapted to switch the overload clutch to a said second mode thereof when the tool is switched on.
An assembly according to any one of the preceding claims, further comprising at least one biasing device for urging the overload clutch to a said second mode thereof.
An overload clutch assembly for a power tool having a spindle for rotatingly driving a working member of the tool and a spindle rotary drive train for rotatingly driving the spindle, the assembly substantially as hereinbefore described with reference to the accompanying drawings.
A switching assembly for switching an overload clutch assembly of a power tool between a first mode thereof and at least one second mode thereof, the assembly comprising:
A switching assembly for switching an overload clutch assembly of a power tool between a first mode thereof and at least one second mode thereof, the assembly substantially as hereinbefore described with reference to the accompanying drawings.
A hand held power tool, comprising:
A tool according to claim30 or 31 wherein the arrangement for detecting blocking events comprises:
A hand held rotary hammer, comprising:
A hand held rotary hammer, comprising:
Dependencies are inferred from the claim text.