The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . b on the controlling lever, and as long as this is helddown the blows continue The air-supply pipe is flexible, so thatit does not impede the movements of the workman. The tools atthe end of the cylinder are simply held in a socket, so that they canbe changed rapidly. Rotative motion can be produced either by electric or pneumaticmotors, and both systems are in wide use. Pneumatic motors arevery suitable when an air-compressing jilant is already laid downfor other tools, while if electricity is us
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . b on the controlling lever, and as long as this is helddown the blows continue The air-supply pipe is flexible, so thatit does not impede the movements of the workman. The tools atthe end of the cylinder are simply held in a socket, so that they canbe changed rapidly. Rotative motion can be produced either by electric or pneumaticmotors, and both systems are in wide use. Pneumatic motors arevery suitable when an air-compressing jilant is already laid downfor other tools, while if electricity is used in the works portable toolsoperated by this agent may be employed instead of the pneumaticones. In the electric drills (fig. 64) a small motor is fitted withinthe body and connected by spur-gears to t^e spindle to effect suitableSpeed reduction. A switch provides Tor stopping and starting the^rnotor; the current is broilgnt through a flexible cable which, like pneumatic hose, is armoured with wire to protect it from smallest drills are simply gripped in the operators hand and D^. Fig. 63.— Tierney Pneumatic Chipping Hammer. (The GlobePneumatic Engmeering Co., Ltd.) A, Cylinder. B, Tool socket, carrying chisel C. D. Piston, which strikes the back of C. E. Handle, screwed and clamped to A. F. Trigger or lever clasped by operators hand and opening valve G, admitting compressed air through connexion H. up passage J,through valve-box K, past valve L, and so against end of D,moving it towards C. As soon as the groove in the piston Dregisters with the hole M^ air is admitted from a small hole(not shown), passes round the groove through hole M andpassage A to the rear of the valve. This acting on the back ofthe valve throws it forward, thus shutting off the supply to therear ot the piston and permitting a small quantity of air to flowto the forward end of the piston for driving it in a backwarddirection. As soon as the air pressure is relieved on theback of the valve b
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
