Hammer drill with camming hammer drive mechanism
AssigneeBlack & Decker Inc.
InventorsNorbert Hahn, Ernst Staas, Achim Buchholz, Michael Stirm, Ralf Bernhart
Life of this patent
Estimating the term…
Abstract
A reciprocating drive mechanism for a striker in a hammer, a rotary hammer, or a power drill having a hammer action, includes a sinusoidal cam channel formed on a drive member and a cam follower, in the form of a ball bearing, attached to a driven member which, due to the interaction of the cam and cam follower, results in a reciprocating movement of the driven member. Both the drive member and driven member can be rotatingly driven by a motor, their relative speeds resulting in the reciprocating movement of the driven member. The driven member is connected to the striker either via a mechanical helical spring or an air spring.
Claims21
A power tool comprising:
- a housing 4;
- a motor 18 mounted within the housing 4;
- a tool holder 20 rotatably mounted on the housing 4 for holding a cutting tool;
- a striker 42 mounted in a freely slideable manner within the housing, for repetitively striking an end of a cutting tool when a cutting tool is held by the tool holder 42, which striker is reciprocatingly driven by the motor 18, when the motor 18 is activated,
- a drive mechanism operatively connected between the motor and the striker, the drive mechanism including:
- a drive member 46 which is capable of being rotatingly driven by the motor 18;
- a driven member 48;
- and
- the driven member is connected to the drive member 46 by at least one cam 54 and cam follower 56,100;200, and to the striker 42 via a spring 44;206;
- and
- wherein rotation of the drive member 46 relative to the driven member 48 results in a reciprocating motion of the driven member 48 which in turn reciprocatingly drives the striker 42 via the spring 44;206, and in a first mode of operation the motor simultaneously drives in rotation both the drive member and the driven member.
Dependencies are inferred from the claim text.