Pneumatic Tools
a class of tools which operate by compressed air. They are usually portable, and used for metal, wood or stone work. The tools are of great variety and are put to many uses, but all of them are one of two typespercussion or rotary. In both types the motor is contained in the tool, and air under pressure is conducted to the tool by a hose.
PNEUMATIC TOOLS Percussion Tools. - Tools of this type opers. are the air hammer, clippers , chippers, caulkers, balast tappers, riveters, etc.
The action in all is essentially the same.
Air, under pressure of 85 to 100 pounds per square inch (except in the case of riveters where it is under higher pressure) is sent into a cylinder containing a piston, which is made to reciprocate in the cylinder by proper valve action, the sure) is sent into a cylinder containing in the cylinder by valve action, the a by proper tool is supported in the front end of the cylinder, and transmits the blow received from the piston to the work.
George Law, an Englishman, invented the first pneumatic tool, a percussion rock drill , in 1865. In this tool, as in most which have followed, the opposite end of the drill from the tool end was fitted with handle and a controlling throttle.
Boyer of St. Louis, Mo., invented the chipping hammer in 1896, and in 1899 Keller brought out the first valveless hammer, in which there is no valve beyond the the position of impact , while the valve hammers are fitted with a reciprocating valve which regulates the inlet and exhaust of the driving air. Modern engineering has introduced many improvements and refinements and many patents have been issued on various methods of actuating and controlling the device. In general the valve type has a longer stroke, and a more powerful blow than the valveless type, while the latter operates at a much higher rate of speed , POACHING