| 摘要 |
689,899. Linkwork. MAY, 0. Aug. 24, 1949, No. 22071/49. [A Specification was laid open to inspection under Sect, 91 of the Acts, Feb. 25, 1950.] Class 80 (iii). A mechanism for operating the ram z of a press from a reversible screw-and-nut drive m, comprises toggle arms a, b and links g, q. The link g is maintained approximately tangential to the arcuate path of the joint f by means of a further link i connecting the common pivot pin h of links g and q to a fixed pinjoint k. The linkwork may be duplicated to operate the ram (or two rams) from the single block m. In a modification the link g is pivoted to the link i at a point on the link i intermediate of its end pins. In a further modification the link i is omitted and the pin h engages a fixed curved guide, which may be non- circular. In an alternative form of driving means, the link q is pivoted to a crosshead reciprocated by a piston rod. In the toggle press shown in Fig. 8, the connecting rod 5 acts in tension to move the tool-carrying slide 11 down towards a platen 33. The toggle crank 3 is pivoted at 7 to the connecting rod and to a link 23 pin-connected to a rigid triangular link 17. The link 17 is pivoted at 15 to the press frame and is operated by a link 25 pivoted to the driving block 29. |
