Patent GB-190201060-A (GB)
Title: Improvements in Pneumatic Drilling, Tapping, Tube Expanding and like Machines.
Filed: 1902-01-14
Granted: 1902-06-05
Abstract: 1060. International Pneumatic Tool Co., and Bergstrom, T. Jan. 14. Drilling; toolholders. - A portable pneumatic machine of the type described in Specification No. 5461, A.D. 1900, for drilling, tapping, tubeexpanding, &c., has a casing 1 containing four cylinders, two piston valves, a vertical crank shaft, and a drill &c. spindle, arranged as described in the prior Specification. A reversing plug valve 26, Figs. 1 and 6, operated by a knurled sleeve 30 on one handle 29, admits fluid under pressure to one of the pairs of cylinders 2, 4, while exhaust takes place through it from the other pair, the position of the valve determining the direction of rotation, or shutting off the air supply. In the positions of the parts shown in the Figures, air is being admitted to the pair of cylinders 4 and exhausting from the pair 2. The air passes through a central aperture 40 and port 39 in the valve plug and thence, through an aperture 37 in the valve casing 25, to passages 36, 34, where the supply divides, part passing through a passage and port 69, Fig. 2, in the bushing 49 of the valve 44 to a second port 70 and passage 71 in the bushing communicating with the cylinder port 51, the passage 71 and port 51 being shown dotted in Fig. 2 which is a section on the line C-D, Fig. 1. The remainder of the air passes through a passage and port 67 in the bushing 48 of the valve 43 to a second port and passage 68 in the bushing communicating with the cylinder port 52 of the second cylinder. Exhaust takes place from the left-hand cylinder of the second pair through cylinder port 53, port and passage 75 in the bushing, a second port 76 and passage 77 in the bushing, passages 33, 35, an aperture 38, Fig. 6, in the casing 25, a recess 41 in the plug, a recess 42 in the casing, and thence, through outlets 65, to the atmosphere. The exhaust from the right-hand cylinder takes place through cylinder port 50, recess 72, and port 73 in the valve bushing, a second port 74 and recess 78 in the bushing to the passage 33, and, thence, as before. By placing the opening 39 in the plug in communication with the aperture 38 a reverse distribution is effected and the motor is reversed. The crank shaft drives the drill spindle through gearing 6 and is supported in end bearings formed by bushings 12, 14 pressed into cap nuts 11, 15, and by a central bearing. The bushes are perforated to admit oil from the hollow cap nuts to the bearings. The lower end of the crank shaft may have a longer bearing by securing a pin 79, Fig. 17, to the cap 11<a>, the pin entering the hollow end of the crank shaft 80 and forming a bearing for it. The back centre 19 is mounted in a sleeve 17 with a star-wheel 18, the sleeve engaging a screwed feed sleeve 16 in the casing. A ball race 23 is placed between the feed sleeve and the drill socket 7. The drill may be ejected from its socket by a drift 20 screwed into the feed sleeve and rotated by a pin &c. when the sleeve 17 is removed. The lower end of the casing is closed by a cap 8 with a left-handed screw and having a segmental recess to receive the cap nut 11, which has a right-handed thread.