Vibration dampening mechanism
AssigneeBlack & Decker Inc.
InventorNorbert Hahn
Life of this patent
Estimating the term…
Abstract
A hammer drill includes a body, a motor; a centre of gravity, and a hammer mechanism driven by the motor in reciprocating movement along a hammer axis at a first distance from the centre of gravity. A counter mass is mounted within the body for sliding movement along a slide axis at a second further distance from the centre of gravity. A biasing member biases the counter mass to a mid-position along the slide axis. The biasing means may be a leaf spring or a helical spring. The counter mass may be slideably supported on rods and may be able to twist about a number of axes.
Claims25
A hammer drill comprising:
- a body;
- a motor located in the body;
- a centre of gravity located within the body;
- a tool holder;
- a hammer mechanism, driven by the motor when the motor is activated;
- a counter mass slideably mounted within the body on a rod and located above the centre of gravity, the counter mass capable of sliding movement in a forward direction and a rearward direction between a first end position and a second end position and the counter mass comprises a vertical C shaped slot which engages with the rod to allow the counter mass to twist about a vertical axis;
- a biasing member which biases the counter mass to a third position located between the first end position and the second end position;
- and
- wherein the mass of the counter mass and the strength of the biasing member are such that the sliding movement of the counter mass acts to at least partially counteract vibrations of the hammer drill generated by the operation of the hammer mechanism.
A hammer drill as claimed in 19 wherein the leaf spring includes a portion constructed of two layers of resiliently deformable material connected to each other.
A hammer drill comprising:
- a body;
- a motor located in the body;
- a hammer drill centre of mass located within the body;
- a hammer mechanism, driven by the motor, when the motor is activated;
- in reciprocating motion along a hammer axis, the hammer axis a first perpendicular distance from the centre of mass;
- a counter mass mounted within the body for a sliding movement along a slide axis between a first end position and a second end position, the slide axis parallel to and spaced from the hammer axis, and the slide axis a second perpendicular distance from the centre of mass, and the second perpendicular distance is greater than the first perpendicular distance;
- a means for biasing the counter mass to a third position located between the first end position and the second end position;
- and
- wherein the counter mass is supported within the body by means for permitting a twisting movement about a twist axis.
Dependencies are inferred from the claim text.