Patent GB-190708382-A (GB)
Title: Improvements in Gas-actuated Percussive Tools.
Inventor: ALLEN CHARLES CHANNING
Filed: 1907-04-10
Granted: 1908-03-05
Abstract: 8382. Allen, C. C. April 10. Percussive hand tools.-A gasactuated percussive tool for drilling, riveting, puncturing, mill-stamping, mining, &c. of the type which consists of upper and lower compression and combustion cylinders with gas inlet openings; both at each compression end and intermediate the ends of each cylinder, has an anvil closing one of the cylinders and struck by the hammer piston and has also improved starting and ignition gear. The two cylinders 12, 10 are separated from an intermediate open chamber 10‹ by the screw-heads 33, 15, the outer end of the cylinder 12 carrying a handle 90 and the cylinder 10 a side handle 91 secured to lugs 93. The gas is conveyed by a three-way joint through pipes 48, 49, containing check valves 50, 51 and regulating valves 52, 54<x>, to recessed enlargements 25, 36x in the opposite compression ends of the two cylinders, the pistons 20, 40 of which are connected by a rod 45. The other ends of the cylinders have the sparking plugs 61, 60, which alternately ignite the mixed gases through a moving contact. The gas in the chamber 25 in the position shown is mixed with air passing through the port 31, and, on ignition of the mixed gas in chamber 10, the down-stroke is produced, and, when the exhaust port 29 is uncovered, burnt gas passes through the port 29, which is slightly above the port 28x. The mixture of air and gas in front of the piston then passes through the passage 28 and through the port 28 into the space behind the piston, being prevented by a vane 30 from passing through the exhaust port. For the return stroke the mixture of air passing through the port 39 and gas in recess 36<x>, which on the previous return stroke had passed to the front of piston 40, is then ignited, and the port 38 finally uncovered to remove burnt gas. A port 37x in a similar position to port 28 then again admits the mixture, a vane 42 serving the same purpose as the vane 30. The battery and induction coils are connected to each of the sparking-plugs alternately by a moving contact operated by the piston-rod. The piston-rod 45 is provided with pins 68 and blocks which slide in slots 67 in an oscillating slotted lever 64, which is pivoted to lugs on the cylinder at 64<x>. This lever has also slots 73 to guide the blocks on pins 72 projecting from a bar 71, which slides in the slot 65 in the lever between the plates 74 connected to one terminal of the induction coil. The .bar 71 at each end of the stroke of the piston makes contact with one of the insulated spring plates 80, connected to one or other of the sparking- plugs. For starting purposes a handle 95, Fig. 6, is used, having a slot 96 to receive the pin of a block, which has a groove 98 to engage the rounded end of the lever 64 and is pressed out by a spiral spring 101. On pressing down the handle, the notched end 102 engages a projection on the lever 64, which thus causes the pistons to move and an initial compression to be obtained. The cylinders are surrounded by water jackets 35, 2], which are connected by a pipe 57, admission being through the opening 55 and exit from opening 58. Instead of the anvil 24 forming part of the cylinder, it may be in the form of a spring-controlled loose socket 106, Fig. 7, its motion outwards being. limited by a shoulder 107, and its other end being surrounded by a gland 109 fixed by a flanged collar 105 and a collar 114 for holding it in place.