| 摘要 |
A hammer drill (100) comprises a main housing (101), a hand grip (109) connected to the main housing (101) via a compression coil spring (171). In the hammer drill (100), a hammer bit (119) is driven by a motion converting mechanism (120), a hammering mechanism (140) and a rotation transmitting mechanism (150), and thereby performs a hammer-drill operation. During the hammer-drill operation, the hand grip (109) is moved against the main housing (101) in a state that biasing force of the compression coil spring (171) is applied. Further, the hammer drill (100) comprises a counterweight (190). The gravity center of the counterweight (190) is set to be lower than the upper edge of a cylinder (129) which is one component of the motion converting mechanism (120). |
| 主权项 |
1. An impact tool which drives a tool bit in a longitudinal direction of the tool bit and performs a predetermined operation, comprising:
a motor which includes a motor shaft, a driving mechanism which is driven by the motor and drives the tool bit, a main housing which houses the driving mechanism, a handle which includes a grip portion extending in a cross direction crossing the longitudinal direction of the tool bit, the handle being configured to be moved with respect to the main housing, a biasing member which is arranged between the main housing and the handle and applies biasing force on the handle, and a weight which is housed in the main housing and movable with respect to the main housing, wherein the driving mechanism comprises a motion converting mechanism which converts rotation of the motor shaft into a linear motion in the longitudinal direction of the tool bit, and a hammering mechanism which includes a bottomed cylinder member, a driving element slidably housed within the cylinder member and a hammering element driven by the driving element and hammering the tool bit, the cylinder member being configured to be driven linearly by the motion converting mechanism and arranged coaxially with the tool bit, the weight is configured to reduce vibration generated on the main housing during the operation by relatively moving with respect to the main housing, the handle is configured to prevent vibration transmission from the main housing to the handle during the operation by relatively moving with respect to the main housing in a state that the biasing force of the biasing member is applied on the handle, the grip portion includes a proximal end part which is close to an axial line of the tool bit in the crossing direction and a distal end part which is remote from the axial line of the tool bit in the crossing direction, and the weight is arranged such that the gravity center of the weight is positioned on a distal end part side with respect to an edge of the cylinder member, the edge being is most distant from the distal end part of the grip portion in the crossing direction. |
