| 摘要 |
843,201. Portable drilling - machines. ENGLISH DRILLING EQUIPMENT CO. Ltd., WALMSLEY, F., PROCTER, R. H., and SANDERS, F. H. W. Oct. 15, 1958 [July, 29 1957], No. 23995/57. Class 83 (3). A rock &c. drilling-machine comprises a drill head f fed along a support c by a toothed element t moved by power means o-p<SP>1</SP>, the rotatable element t meshing with a rack q on the drill head and a rack r on the support c, so that the drill head moves a distance equal to that moved by element t along rack r plus the distance which element t moves rack q as it rotates along rack r. The support c is angularly and vertically adjustable in a frame a having jacks b for engaging the roof and floor of a tunnel. A pneumatic &c. motor g drives the drill spindle through a chain h and a changespeed gear-box i, drill rods being guided by rollers m on a clamp k used when coupling the drill rods. A rack r is attached to each side c<SP>1</SP> of the support c, and an opposed rack q to each side of the drill head. The sprocket, pinion, &c., t meshing with each pair of racks, is carried by a cross-head s fed by the piston rod p<SP>1</SP> of an hydraulic &c. cylinder o, which is attached by a nut o<SP>1</SP> to the end of support c. The ratio of drill-head traverse to piston traverse may be more than 2: 1, by using duplex pinions t having different numbers of teeth on the parts engaging the different racks. |
