| 摘要 |
496,591. Hydraulically-operated machine-tools. ARCHDALE & CO., Ltd., J., and WRIGHT, I. H. June 16, 1937, No. 16709. [Class 69 (ii)] [Also in Groups XXII and XXIII] Means for effecting reversals of movement of a hydraulically-operated milling, grinding, or like machine-tool slide comprises spring or weight-loaded valves adapted to control the exhaust from the slide-operating cylinder and also the fluid for a reversing valve, and trip mechanism responsive to the slide movements for controlling the spring or weight-loaded valves. The slide f, Fig. 1, moved by the piston h in the cylinder g may carry a rotary tool a and a follower c co-operating with a pattern d, Fig. 2. A pump i draws fluid (usually oil) from a reservoir j and passes it through the reversing valve l and also to a pipe line u. In the position of the reversing valve shown, Fig. 1, pressure fluid passes through the pipe q to the trip-controlled valve m whence it passes through the pipe r to the cylinder g. Piston h and slide move to the right, fluid being exhausted through pipe s, second valve m, and pipe t to the reversing valve and reservoir. Near the end of a required stroke movement, the lever p is moved to free the right-hand valve m which moves to the left under the action of its spring n. This admits pressure fluid from the pipe u through the space y to the pipe v and thus moves the reversing valve and so effects the reverse movement of the slide f. Pressure fluid now passes through the space x in the right-hand trip valve from the pump i, and the valve is forced back against the spring pressure until re-engaged by the trip lever o. A similar reversal takes place when the slide reaches the opposite end of its movement. The trip lever p, in the embodiment described, is connected to a sliding rack bar 6, Fig. 2, engaged by a pinion 5 carried by a ratchet wheel 4. Spring- pressed pawls 3 are brought into engagement alternately with the ratchet wheel when the slide f approaches the ends of its movement, thus holding the ratchet wheel and giving movement to the rack bar to operate the valve trips. A follower c engaging a pattern d carried by the work-table e, is mounted on the end of a lever 2 which is pivotally mounted on another lever 9, the pivotal movements of which are limited by stops 10 and resisted by frictional engagement at one end with a fixed rod 11; this arrangement brings the follower c into a position in advance of that which it would otherwise occupy and it thus starts the reversal action sufficiently in advance to overcome the reversal lag and give the length of travel of the slide required. The work and pattern are mounted on the table e which can receive horizontal feed movements in directions at right-angles and also vertical feed movements, the latter being made at each reversal of the slide f or at other intervals. |
