Patent GB-472181-A (GB)
Title: Improvements in or relating to milling, planing and like machines for copying
IPC: B23Q35/18
Filed: 1936-04-02
Abstract: 472,181. Milling, planing, and grinding machines for copying ; drilling; fluidpressure servomotors. CINCINNATI MILLING MACHINE CO. April 2, 1936. No. 9785. Convention date, April 2, 1935. [Class 83 (iii)] [Also in Groups XXIII and XXIX] In a copying machine for producing blanking- dies by milling or grinding cutters, or shaping cutters, or both, a work holder and a cutter slide are movable by hydraulic cylinders in directions perpendicular to each other, the two movements being controlled simultaneously by a tracer on the cutter slide engaging a pattern on the work holder. The cutter slide carries a milling cutter or grinding disc and a shaping ram reciprocated vertically by a fluid pressure cylinder and the work may be cut by either tool or may be roughcut by the milling cutter and finished by the shaping tool. The base 10 of the machine supports the work table 12 slidable on guides 11 by the piston rod 22 of a fluid pressure cylinder, and also has guides 13 for the cutter slide 14. A slide 16 is movable vertically on the slide 14 by a hand-operated screw 17 and carries the shaping ram 19, the milling or grinding spindle 20 and the tracer 80. Shaping; cutter-releasing tool-boxes.-The shaping ram comprises a body 189, Fig. 2, slidable in the square-sectioned interior of a casing 194 which is angularly adjustable about a pivot 196 in a barrel 173 rotatably supported by ball bearings 174 in a boss of the slide 16. Adjustable shims 191 at right angles secure the fit of the ram in the casing 194. The holder 187 for the cutter 96 is pivoted at 188 in the body 189 and is connected by a link 185 to the piston rod 180 of a fluid pressure cylinder 182 mounted on the slide 16. Downward motion of the link 185 rocks the holder 187 into cutting position and upward motion rocks the tool out of contact with the work. Angular adjustment of the casing 194 is facilitated by a scale and pointer on the barrel 173 and casing respectively, locking being effected by a through bolt and slots. The adjustment is effected by a screw 200, against springs 197, and is for the purpose of enabling the cutter to produce " draft " on the die being made. Collars 229, 230 on the piston rod operate the stem 228 of a pilot reversing valve 224 controlling the main reversing valve 209. Fig. 15. Oil passes from the supply line 104, fed by the pump 101, by the pipe 207 to the valve 209 and then, with the plunger 210 in the left-hand position shown, by pipe 214 to the bottom of cylinder 182, thus raising the ram 189. Exhaust from the upper end of the cylinder passes by pipe 218, valve 209 and pipe 219 to two resistances 220, 221 and then to ports 222, 225 at opposite ends of the valve 209 and also to ports 223, 226 of the pilot valve 224. The port 226 being closed by the valve plate 227, the oil passes to the sump 79 through port 223 and pipes 238, but when the plate 227 is thrown over to the port 223 by the collar 230, pressure rises in the pipe 233, and falls in the pipe 232 and the valve plunger 210 is moved to the right to reverse the flow to cylinder 182. Branches from the pipes 233, 238 are led to a stop valve 242, which is inoperative in the position shown, but when the valve is moved to the right by a hand lever 245, Figs. 1 and 15, the pipes 233, 238 are connected so that the next time the ram reaches the top of its stroke and the port 223 is closed the pipe 233 will still be connected to exhaust and no movement of the valve 209 will take place. The ram is thus stopped in its upper position with the tool clear of the work. Copying-mechanism for shaping.-The shaping cutter 96 is caused to copy a roughly shaped die-opening in a work piece by relative motion of the slides 12, 14 together with rotation of the barrel 173 in its bearings 174, the cutter following a path as shown in Figs. 8-10. Oil is supplied to the cylinder 23 for the slide 12 by a reversible variable delivery pump 28, Fig. 15, and to the cylinder 31 for the slide 14 by a similar pump 36. The quantity and direction of output from the pumps is controlled by lovers 37, 38 which are connected to slidable rods 39, 40, provided with slotted yokes 43, 44 at right angles to each other. A pin 45 passes through both slots and when the pin is at the point of intersection of the axes 46, 47 of the yokes the output from both pumps is zero but when the pin is displaced from this position the direction and quantity of output of either or both pumps is varied according to the position of the pin. The pin is carried by a plunger 48 sliding in a cylinder 49 which is attached to the tracer head 50 to rotate therewith so that the pin may be moved by the plunger in any radial direction, the resultant relative movement of the cutter and work being in a direction parallel thereto. Rotation of'the tracer head and cylinder 49, with the pin 45 at a stationary radially-displaced position, causes rotary motion of the cutter barrel 173 and the speed of operation of the slides 12, 14 depends on the radially displaced position of the pin. The tracer head 50 and barrel 173 are rotated simultaneously by a chain 92 driven by a hydraulic motor 89 which is adjustable in position to vary the tension of the chain. Oil for moving the plunger is supplied by a variable displacement pump 52, which is supercharged by the pump 101 and is adjusted to limit the speed of operation of the plunger by means of a spring 58 and cam 56 operated by a handle 60, Fig. 1, moving over a graduated dial 62. The tracer 80, Fig. 15 acts by lateral pressure from the pattern to displace a valve 81 normally pressed down by a spring 82. The pump 101 supplies oil direct by a pipe 102 to two ports 105, 106 of a secondary valve 53 which is controlled by the tracer valve 81, and a third pump 70, supercharged by the pump 101, supplies oil to a differential valve 73 which controls movement of the plunger 48. In operation, with the tracer out of contact with the pattern, the tracer head 50 is rotated by a hand wheel 120, Fig. 1, so as to cause the cylinder 49 to lie along the desired line of approach of the tracer to the pattern, an arrow being provided on the wheel 120 to indicate this line. The spring 82 maintains the valve 81 in the lowest position shown in Fig. 15, so that the pipe 116 will be open to exhaust and the pipe 117 will be completely closed. Oil from the pump 101 then passes to both ends of the valve plunger 110 through the interior thereof, the pressure at the right-hand end being low due to the pipe 116 being open to exhaust, and the plunger moves to 'the right-hand position shown. Oil supplied by the pump 52 passes by pipe 122 to valve 53 and then by the interior of the plunger 110 to pipe 124. A valve 162 on the line 124 is connected by pipes 159, 161 to the pipes 115, 116, and since the latter is open to exhaust the valve will move to the right, thus admitting equal pressures from the pipe 124 to the pipes 165, 166 leading to the motor 89 and preventing it from rotating. Oil passing through the centre of the valve proceeds by the pipes 171 and 64 to the cylinder 49 to displace the pin 45 and cause feed of one or both of the slides 12, 14 according to the position to which the hand wheel 120 has been turned. The plunger 48 has a reduced portion 65 by which the oil flows to the exhaust line 65<1> and this passage increases in size as the plunger moves and so reduces the pressure in the pipe 64, until a balance is obtained with the plunger 48 stationary. The cylinder 49 to the right of the plunger is connected by pipe 701 to the pump 70 and the pressure in this line is governed by the amount which can pass by the branch 71 through the differential valve 73 and then to exhaust by the pipe 77, balancing valve 316 and a fixed resistance 78. Pipes 78<1>, 79<1> lead to opposite ends of the valve 73 from the exhaust line 77 and the supply line 64 respectively so that when the plunger 48 is first moved to the right the valve body 74 will also move to the right and increase the passage past the conical part 75 thereof, reducing the pressure in pipe 71 and thus assisting movement of the plunger 48. When pressure in the line 64 falls, however, due to the increased passage at 65, the valve body 74 will return to the left and increase the pressure at the right of plunger 48 to bring it to rest. When the tracer engages the pattern the valve 81 is raised to a central position in which oil may pass equally from the pipes 116, 117 to exhaust, thus moving the secondary valve plunger 110 to a central position and the valve body 162 to the left, since this valve body has different areas at opposite ends. All the oil passing through one of the pipes 124, 125 will then proceed by pipe 165 or 166 to the motor 89 to rotate the tracer head and cutter and determine the relative direction of feed of the slides 12, 14, whilst oil will also be delivered by pipe 123 through balancing valves 143, 153 to the cylinder 49 to determine the speed of these slides. If the surface being traversed by the tracer is comparatively straight all the flow will go to the pipe 123 for feed of the slides but if the surface is curved the flow in pipe 123 will be reduced and that in one of the pipes 124, 125 for rotating the motor 89 will be increased so as to cause the work and pattern to be moved in an orbital path around the cutter and tracer. The rotation will continue until the arrow on the wheel 120, and therefore the resultant direction of the next feed traverse, is parallel to the tangent to the pattern at the point of contact of the tracer therewith, and thus pressure on the tracer will be reduced, rotation will stop and further traverse will take place. The balancing valves 143, 153 are arranged in series with the feed pipe 123, valve 143 being also connected to motor pipe 124 and valve 153 to motor pipe 125 so that the valves serve to maintain the distribution of flow in the pipes 123..125 which is determined by the valve 53. The tracer is tapered as show