| 摘要 |
934,620. Tailstocks. SPRINGFIELD MACHINE TOOL CO. Dec. 10, 1959 [Dec. 10, 1958], No. 42015/59. Class 83 (3). A fluid pressure operated tailstock or like clamping device comprises a member movable towards or away from a workpiece, a piston forming a variable volume fluid chamber with the member, and a pressure control means to limit the pressure in the chamber, and the force applied to the work. The tailstock comprises a cylinder 15 secured to a plate 10, slidable on the bed of a lathe &c. 11, a spindle 25 having a head 28 slidable in bushes 47, 18, secured to the cylinder 15, having a centre 85 and a collet 35 secured to the bush 18 and actuated to lock the spindle 25 when the resistance to forward movement of the latter reaches a predetermined value, by an axially slidable piston 60. In operation, fluid is supplied to a chamber 67 between the bush 47 and piston 60, and the latter is moved to the right, thus increasing the pressure in the fluidfilled space 65 which then moves spindle 25 until centre 85 abuts the work. The fluid in space 65 is allowed to leak-off at 77 at a predetermined pressure and further movement of the piston 60 reduces the volume of space 65 and contracts collet 35 to clamp spindle 25. The flow of fluid is reversed to release the collet and piston 60 then engages a collar 45 on spindle 25 to move the centre away from the work. Fluid is supplied from a tank T, through a line 95, to a directional valve 100, and thence to, or from, connections 75, 77 in cyl nder 15, via lines 105, 106. Spindle head 28 may be replaced by a head extending to the right-hand end of the spindle, bush 18 having a single diameter bore. A flexible cover 30 protects spindle 25. |
