Patent ID: 6754962
Filing Date: 2004-06-29
Classification: A01D,F16D

Abstract:
A bush cutting apparatus comprising:a drive source having a body and an output shaft mounted in the body for undergoing rotation; a cutter-blade driving shaft axially spaced from and operatively connected to the output shaft of the drive source for rotation therewith; a cutter blade connected to the cutter-blade driving shaft for rotation therewith; a housing connected to the body of the drive source; a clutch mechanism disposed in the housing and having a rotational member mounted on the output shaft of the drive source for rotation therewith, at least one a clutch moving member having a tapered outer side surface and being mounted on the rotational member for sliding movement along a radial direction of the rotational member, a clutch drum mounted on the cutter-blade driving shaft for axial movement therealong for engagement with the clutch moving member and having a tapered portion with an inner surface corresponding in contour to the tapered outer side surface of the clutch moving member and a hollow connecting shaft connected to the cutter-blade driving shaft, a collar slidably mounted around the hollow connecting shaft, a bearing mounted around the collar and connected to the housing, and a clutch resilient member for biasing the clutch moving member toward an axial centerline of the rotational member; and a brake mechanism disposed in the housing and having a brake shoe formed at a tip of an open end portion of the clutch drum defining the greatest diameter region of the tapered portion of the clutch drum, a brake pad connected to the housing and disposed opposite to the brake shoe in an axial direction of the cutter-blade driving shaft, and a braking resilient member disposed between an end of the collar and the clutch drum for biasing the brake shoe into pressure contact with the brake pad; wherein when the rotational member is not rotated by the drive source at a rotational speed higher than a preselected rotational speed, the clutch moving member is maintained disengaged from the clutch drum due to a biasing force of the clutch resilient member so that the brake shoe is pressed against the brake pad to apply a braking force, and when the rotating member is rotated by the drive source at a rotational speed higher than the preselected rotational speed, the clutch moving member is moved radially outward to press the clutch drum by a centrifugal force in such a manner that the clutch drum is caused, by the tapered outer side surface of the clutch moving member, to slide in a direction to disengage the brake shoe from the brake pad.