GB118518A - Improvements in connection with Hydraulic Shearing and like Presses. - Google Patents

Abstract

118,518. Stewart & Co., D., and Holmes, T. E. Nov. 16, 1917. Shearing.-An hydraulically-operated shearing- press or the like of the kind in which the work is carried by a rising and falling table is constructed so that the table is lowered, not by the pressure on the work, but by a mechanical connexion with a moving member of the press. A lost-motion device forms part of this connexion to enable the shearing-blade to be moved relatively to the work. A clutch is also provided between this mechanical connexion and the table-lowering gear, this clutch being controlled by a ram operated by a cylinder in communication with the main ram of the press. As shown, the work-table B is supported by adjustable arms A<3> of a parallel-motion link system comprising lever arms A<2>, A<5> connected by links A' all controlled from a shaft A, which is connected by a link C to a counterbalancing hydraulic ram C<1> in a cylinder C<2>. The shaft A is rocked to lower the table B by means of a link D<7> connected to the moving head D<8> of the press and operating a lever D<4> on a counterbalanced shaft D<5> by means of a slot D<6>, and a pin on the lever D<4>. The shaft D<5> transmits motion by means of a link D<3> and a freely-mounted clutch element D<1>, Fig. 2, to the shaft A, the movable element D<2> of the clutch being operated to close the clutch by a lever E operated by a ram E<4> of a cylinder E<5> supplied from the main intensifier supply to the press through a pipe E<8> and non- return valve E<7>. When it is required to hold the table in its lowered position for a certain time, the pressure is maintained in the cylinder E<5> until the main hand-lever of the machine reaches a predetermined position, whereupon it is caused to operate by means of a link G<3>, lever G<4>, and link G<5>, a valve G<1> which connects the cylinder E<5> to exhaust, the clutch D', D<2> being then unclutched and a valve H opened by means of a link and lever system H<2>, H<3> with a lost motion. The valve H admits water from the accumulator to the cylinder C<2> and thereby raises the table to normal position.