GB482133A - Improvements in, or relating to, boring machines for use in rock, coal or similar material - Google Patents

Abstract

482,133. Cutting slots in rock &c. HARDYPICK, Ltd., and HURD, F. W. Sept. 23, 1936, No. 25871. [Class 68 (i)] [Also in Group XXII] In cutting slots in a rock, coal, &c. face for receiving roof supports, a hole is drilled into the face and a cutterhead is then used having a non-rotary head which enters the hole to serve as a guide and carries two radial cutters rotating on axes perpendicular to the hole so as to elongate the latter and form it into a slot. A machine for carrying out the method comprises a fluid or electric motor 2, Fig. 2, to which is attached a casing 11 carrying a drill spindle 5 co-axial with the motor. The spindle is driven by an annular gear 9 thereon, a stationary idle pinion 8 and a gear 6 on the motor shaft 4. A hollow spindle 18, parallel to the spindle 5, is driven therefrom through an idle gear 16 and drives two further parallel spindles through its gear 13. The three spindles drive three shafts 21-23, Fig. 1, supported by bearing members 24, 25, each shaft carrying a helical fin for withdrawing the cuttings from the slot being formed. The central shaft 22 is screwconnected at 40 to a stub shaft 34 journalled in a frame 27 attached to the bearing 25. A bevel gear 37 in the shaft 34 drives opposed radial cutters 42 also journalled in the frame 27. In operation a drill is inserted in the spindle 18 and a hole, equal in length to the depth of slot required, is drilled in the coal &c., face. The drill is then removed and the shafts 21-23 inserted in the spindles 18 and a head 28 on the frame 27 is guided in the drilled hole whilst the cutters 42 cut away the sides of the hole to form the slot. Rotation of the bearing 25 under the action of the driving torque is prevented by opposed surfaces 45 thereon engaging the upper and lower faces of the slot. The spindles 18 are arranged in a plane offset from the motor casing 2 in order that they may operate close to a roof &c., face, and a drill may be inserted in the spindle 5. The cutters 42 may be rotated by worm gearing instead of bevel gearing, the two cutters then rotating in the same direction and being of opposite hand. The device may form an integral part of an electric or pneumatic drilling machine or may be driven by a flexible shaft, and is fed during operation by hand or by any known mechanical means. The drill for forming the initial hole has a helical fin 43, Fig. 4, and blades 44, 44a of different diameter arranged one behind the other at right-angles.