Rotating electric hand tool implement with safety routine

• US 20010042630A1
• Filed: 05/02/2001
• Published: 11/22/2001
• Est. Priority Date: 05/02/2000
• Status: Active Grant

• Current Assignee: Hilti Aktiengesellschaft (Hilti Martin Family Trust)
• Original Assignee: Hilti Aktiengesellschaft (Hilti Martin Family Trust)
• Inventors: Bongers-Ambrosius, Hans-Werner, Kristen, Ferdinand
• Granted Patent: US 7,011,165 B2
• Time in Patent Office: Days
• US Class Current: 173/1
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for

Abstract

An electric hand tool apparatus (1) for driving a drill-like tool, which carries out an at least partial rotational movement, has within a housing (2), an electric motor (4) without or free of collector and slip ring, the rpm of which can be controlled by motor control electronics (3), wherein an rpm-dependent clutch (5) for transferring the torque is disposed in a force transfer path from the electric motor (4) to a transmission (6). Optionally, to prevent an excessively high twisting of the housing (2), a sensor (7) is evaluated and the rpm of the electric motor (4) is reduced in order to sever the transfer of force by the rpm-dependent clutch (5).

Claims

1. An electric hand tool apparatus for driving a drill-like tool effecting at least partially a rotational movement and comprising a housing (2), an electric motor (4), free of a collector and slip ring for producing a torque, motor control electronics (3) within said housing (2) in operational engagement with said electric motor (4), a force transfer path from said motor (4) to said transmissions (6) and a rpm-dependent clutch (5) in the force transfer path for transmitting torque from said electric motor (4) to said transmission (6).

2. An electric hard tool apparatus, as set forth in

claim 1

, wherein a sensor (7) is connected with said housing (2) for detecting a future, excessively high twisting of said housing (2).

3. An electric hard tool apparatus, as set forth in

claim 1

, wherein said electric motor (4) is a magnetic reluctance motor.

4. A method of operating an electric hand tool apparatus for limiting an excessively high twisting of a housing of the electric hand tool apparatus in the event of an obstruction of the apparatus during operation, the electric hand tool apparatus comprising a housing (2), an electric motor (4) for producing a torque and being free of a collector and slip ring, motor control electronics (3) within the housing (2) in operational engagement with the electric motor for controlling rpm of the torque thereof, a transmission (6) within the housing (2) for transmitting rotational movement along a force transfer path from the motor (4) to the transmission (6), and a rpm-dependent clutch (5) in the force transfer path for transmitting torque from the electric motor (4) to the transmission (6), a sensor (7) connected with the housing for detecting a future excessively high twisting of the housing (2), comprising the steps of triggering a safety signal when an excessively high twisting of the housing is recorded by the sensor (7), reducing the rpm of the electric motor (4) via the motor control electronics (3), and with the reduction of the rpm interrupting the transfer of torque over the force transfer path.

5. A method, as set forth in

claim 4

, comprising the steps of polling and evaluating the safety signal before accelerating the electric motor via the motor control electronics (3).