| 摘要 |
Method and apparatus for providing motive power to a tool are disclosed. A preferred power mitre box (10) including a base (12), a table (14) and electrically-powered motor unit (18) suitable for driving a saw blade (20) is described. The motor unit (18) includes an armature (40) and an arbor shaft (22) which are respectively supported by armature bearings 42 and arbor bearings 44 and are preferably substantially parallel and of substantially the same length. Also, the distances between the armature bearings (42) and the arbor bearings (44) are preferably substantially equal. The relatively large distance between the arbor bearings (44) causes the blade (20) to have very little play or deflection due to looseness in the bearings (44). In preferred embodiments, a speed reducer assembly (34) is located on the opposite end of the arbor shaft (22) in relation to the blade (20). Also, the speed reducer assembly is preferably of the cog belt type.
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