Patent GB-541931-A (GB)
Title: Improvements relating to drilling apparatus
IPC: E21B19/081
Filed: 1940-04-05
Abstract: 541,931. Drilling - - machines. SULLIVAN MACHINERY CO. April 5, 1940, Nos. 6198 and 6199. Convention dates, April 19, 1939, and March 5, 1940. [Class 83 (iii)] [Also in Group XXIII] A rotary drilling-machine particularly for drilling hard rock has the drill driven by an electric motor and fluid pressure feeding means which operate automatically in accordance with the resistance to drilling, the feed being stopped by means of a torque reaction member when a predetermined resistance is exceeded. The drill support 3 comprises a trunnion member 4 having a swivel plate 5 which may be clamped to a support. The member 4 is fitted with a tube 6 which provides a swivel mounting for a support 7 which is bored to receive the slidable feed cylinder 8. Dirt-excluding seals are provided at 9. The support 7 is normally locked in the Fig. 1 position relatively to the plate 5 by means of a spring plunger 16. The feed cylinder includes a piston 17 on a piston rod 18 carrying a flanged plate 22 which is secured to a control head 51. Packing is provided at 32 and a dirt seal at 40 for the front end of the piston rod. The feed cylinder heads 30, 31 have depending bosses which receive a threaded tube 41 running in a nut 43 in the support 7. The screw may be rotated by a handle 47 to feed the cylinder 2 bodily through the support 7. The drill rotating means comprises a high speed motor 54. The front head of the motor includes a housing 64 for a cooling fan 65. The motor has limited rotary movement in the control head on bearings 70. Power is supplied to the motor through a connector plug 77. Fluid for feeding the drill is supplied to the control head through a line 82 leading through a strainer 83 to a valve 85 connected to a threaded control rod 90 extending through the bore of the tube 41 to a manual control 93. telescopic connections being provided so that the valve may be operated in all positions of the control head. The valve 85, Fig. 8, is supplied with fluid through the port 97 whence fluid may pass to a groove 103 connected to the interior of piston rod 18. A port in this rod allows fluid to pass to the front of the piston 17 to move the same rearwardly to its Fig. 2 position. In another position of the valve 85 fluid is supplied to the rear of the piston from a valve groove 101 by a flow through passage 117 torque control valve 118, Fig. 34, passages 119, 120 and tube 123. The motor switch 79 may be controlled by the valve 85, by means of a diaphragm 130, Fig. 29, clamped between the head 20 and member 114. The diaphragm engages a plunger 131 which operates the switch. A three-way valve 135, Fig. 34, is included in the circuit which is arranged so that when valve 85 is positioned for forward feed and the valve 135 correctly positioned, the diaphragm is actuated to close the motor switch. When pressure is exhausted from the diaphragm a spring acts to break the switch and stop the drill motor. In one position of the valve 85 the forward feed is in operation and the drill may be fed until it engages the bottom of a starting-hole. Successive forward movements of the valve then produce first a cut off of the feeding pressure, then starting of the motor through fluid pressure applied to the diaphragm 130 and then feed of the drill with the motor in operation to form the hole. When the work is completed the valve is fully retracted thereby causing stopping of the motor and initiation of the reverse drill movement. The motor may be started at any time independently of the movements of the valve 85 by turning the valve 135 to admit fluid pressure to the diaphragm 130 through a line 143. In order to supply drilling fluid to the drill bit the supply chamber 81 is connected through a manually-controlled two-way valve 146 co-axial with valve 135 to a passage 149, Fig. 21 leading to a bore 163 and passage 164 in the adapter nut 76 which secures the drill. The torque of the motor 54 automatically regulates the forward feed by the action of a valve 118, Fig. 34. The motor 54 which has limited rotation in the control head 51 has an end plate which carries a torque pin 165 engaging a groove in a reciprocable valve stem which co-acts with a seating 170, Fig. 23. A spring 176 acts oppositely to the torque reaction and normally holds the motor stator against rotation during drilling. If a predetermined torque is exceeded the part 166 moves against the spring and seats the valve thus cutting off flow to the forward feed passage 119. The head 186 of the drill tube has an axial passage 188, Fig. 30, for flow of drilling fluid and the core bit 189 may consist of a matrix material embedded with diamonds. Alternatively a plug bit may be used. For breaking the core left by the bit 189 a breaker consisting of a sleeve 191 cut away as shown in Fig. 32 may be employed. A reinforcing rib 194 welded to the tube acts laterally on the column left by the core bit to apply a breaking pressure thereto. A forward chamfer 195 assists in directing the core within the tube. When in operation the feed cylinder reaches the end of its stroke (dotted position in Fig. 1), the feed is reversed by shift of valve 85. When this return is completed the operator may by manipulation of the handle 48 of the feed screw feed the whole cylinder 2 forwardly in the support 7 after which another feed cycle may be performed by manipulation of valve 85. In this way two feed movements are obtained without disturbing the clamping means 5. In some cases the feed may be performed entirely by the manual feed of the cylinder 2 in the support 7 the valves 135 and 146 being manipulated to start the motor and to supply drilling fluid when required. When the coupling 187 is released the drill may be swung aside on its trunnions 4 so that the core barrel may be moved from the drill hole or drill rod, sections may be added. The drilling speeds may be from 3,600 to 7,200 R.P.M. and the feed pressure up to 1,400 lbs. per square inch of projected bit area. Modified forms of the control valve 85 and torque controlled valve 118 are described. With the modified torque control valve the fluid supply to the rear end of the feed cylinder is interrupted if overload occurs as described above and when a still greater overload occurs this space is opened to exhaust. In this case the manual feed of the cylinder through its support may be operated simultaneously with the hydraulic power feed so that the drill bit may be fed forwardly the combined travels of the feed piston in its cylinder and the cylinder in its support without interrupting the power feed.