Patent GB-1026673-A (GB)
Title: Control mechanism
IPC: B23Q5/00
Filed: 1962-10-16
Abstract: 1,026,673. Lathes. BULLARD CO. Oct. 16, 1962 [Oct. 16, 1961], No. 39205/62. Heading B3T. [Also in Divisions F2 and H2] A control mechanism for a machine tool such as a lathe having a work-table 10 and a tool post 25, wherein the tool post 25 is adapted to be moved along intersecting paths comprises a motor 43, the drive from which is conveyed through a variable speed unit VS in the form of epicyclic gearing C and D. The variable speed drive is transmitted via gears 30 to 33 to parallel shafts 17 and 20; shaft 17 effecting longitudinal traverse of the tool post 25 and shaft 20 which is splined and carries bevel gear 21 which meshes with gear 22 to effect crosstraverse of the tool post. To reverse the direction of movement of the tool post fluid-actuated clutches 34 and 35 are located between gears 30, 31 and 32, 33 respectively. The motor 43 is also connected to a variable volume hydraulic unit 50 which in turn is connected via pipes 53, 54 to a non-variable hydraulic unit 52, the latter being mechanically connected to the outer element 58 of the epicyclic gearing D. These hydraulic units comprise the variable speed device, of the nut VS, and are connected to the second or outer element of the epicyclic arrangements C and D. Dissimilar ratio gearing is provided between shafts 61, 65 and the output shaft 40 by means of worm gear 70, shaft 71, worm 72, a one-way clutch 73<SP>1</SP> and a clutch 74 controlled by a cam 111 described below. To facilitate movement of the tool support in either direction along either of its paths of motion, a feed control device (Fig. 2, not shown) is provided which includes a cam 76 which operates switches 77, 78, 79, 80 (Fig. 2A, not shown). The cam movement is effected by rotation of the shaft 99 via bevel gears 100, 101 by a flexible shaft 102 attached to gear 101 and which carries a hand grip 108 (Fig. 3), the turning of the hand grip subsequently actuates switches 77 to 80. The switches may be incorporated in circuits having solenoids 82 to 85 for operating valves 82<SP>1</SP> to 85<SP>1</SP> (Fig. 7, not shown). The outlet lines 87 to 90 of the valves are connected to the clutches 34, 35. To control the operation of the unit VS movement of the lever 51 of the unit 50 may be provided by means of a reciprocable piston 110, the movement of which is effected by a servo-mechanism including a cam 111 and a servo-valve 112. The cam 111 is connected by a rack 149 and pinion 148 and a clutch 146 to an epicyclic gear 130 which is connected to gear 38 driven from the output shaft 40 of the unit VS, and to a shaft 139 which may be axially displaced by a crank and connecting rod assembly so that the calibrated displacement of the disc 138 in frictional engagement with disc 137 driven from the table drive conventional variable speed gear 12<SP>1</SP> will effect different feed rates. The shafts 26, 27 are connected to position data storage means in the form of rotatable, adjustable cam discs 291 with co-operating switching means 296, 603 and 304 (Fig. 9, not shown), which in conjunction with motor-driven function data storage means in the form of a perforated hollow cylindzical drum with propositioned dogs provides automatic operation of the electrical circuits to effect independent, combined or sequential operation of the feed to the tool post and work-table of the machine tool. Electrical circuits are described in relation to the operation of the control device.