| 摘要 |
1,163,819. Sawing. ROCKWELL MFG. CO. 11 July, 1967 [13 July, 1966], No. 31814/67. Heading B5L. [Also in Division H2] A portable power-driven circular saw comprises an electric motor mounted in a dielectric casing 11 and having its current carrying parts isolated from the shaft 29 by a dielectric sleeve 15, a circular saw 71 driven from the shaft via gears 41, 41a and an impact resistant housing 1 surrounding the motor and forming a hollow handle 91 in which a trigger-operated switch is mounted. The housing 1 is made in halves 7, 5 from a dielectric polymer material the halves being secured together by screws 95 in order to clamp the motor casing 11 within the housing; the casing is made from an asbestos filled phenolic material. An end cap 9 is secured to half 7 and is removable in order to gain access to the motor brushes (21, Fig. 7). The shaft 29 is formed with a portion 41 arranged to engage a gear-wheel 41a rigidly mounted on an arbor 63 which is rotatably mounted in a fixed guard portion 3 secured to the housing half 5. The saw blade is secured to the arbor by a slip clutch arrangement comprising two washers 67, 69 clamped by a screw 73. A movable guard portion (57, Fig. 10) is pivoted on a bush 59 mounted in the portion 3 and is normally urged to a closed position by a spring (62). A cooling fan 37 for the motor draws air through an opening 27a and discharges through a slot formed in a cover 32 adjacent the saw blade. |
