| 摘要 |
747,255. Percussive drills. LICHTBLAU, W. Nov. 24, 1952 [Nov. 23, 1951], No. 29636/52. Class 124 A rotary boring machine in which percussive action is imparted simutaneously with the rotary movement by the action of a toothed member in the housing with a toothed member connected to the drill steel has the number of teeth on each member so arranged relative 'to the number of revolutions per minute that the percussive action has a frequency of 8,500 to 11.500 blows per minute. As shown, a housing 1 has mounted therein a member 7 having teeth on a ring 6 urged by a spring 11 into engagement with teeth on a ring 6a attached to a part 5 carrying a drill steel in a socket 3, the part 5 being driven by a shaft 8 on which the member 7 is slidable. As the member 5 rotates the part 7 is moved by the sliding action of the teeth, against the spring 11 and as the points of the teeth pass over each other the part 7 moves by the spring action and strikes a blow on the part 5. The member 7 may be mounted in leaf springs 12 for limited rotary movement. If an air motor is employed exhaust air carrying with it some oil may be used to cool and lubricate the teeth. The slope of either side of the teeth may be different. |
