Patent GB-1158192-A (GB)
Title: Force-Applying Mechanism
IPC: B30B1/26
Filed: 1966-11-04
Abstract: 1,158,192. Shearing; metal working presses. MESTA MACHINE CO. 4 Nov., 1966 [21 April, 1966], No. 49642/66. Headings B3H, B3P and B3W. [Also in Divisions B8, F1 and F2] A force applying mechanism for displacing at least one of a pair of force transmitting members relative to the other, comprising first means for alternately advancing and withdrawing one of said members against and from load means disposed between said members and second means connected to one of said members and operative during withdrawal movements of said first means from the load means, to incrementally urge such member a predetermined distance toward said other member. Fig. 1 shows a shear 10 for cutting a bloom 16 coming from a continuous casting apparatus. The shear frame includes two sides 14 and a block 20 on which the stationary cutter 24 is mounted. The movable cutter 26 is carried by a block 22 which slides in guides 18 formed in the sides 14. A main shaft 36 mounted in bearings 38 carries a worm wheel 39 on each side of which is formed an eccentric 46, 48. A pitman 34 operated by the eccentrics is connected to a driver block 30 which also slides in the guides 18. A screw 54 is mounted by a flanged head in the driver block 30, for rotation about its longitudinal axis and its threaded end engages a nut 58 secured in the block 22. A gear wheel 76 is keyed to the shank of the screw so that the two rotate together but the gear wheel can move axially of the screw. A motor 98 drives the gear wheel 76 through reduction gears. Operation.-As the eccentrics 46, 48 rotate the cutter 26 is moved forward against the bloom 16 during half a revolution and during the remainder of the revolution, in which the driver block 30 is retracted the screw 54 is rotated so that the cutter block 22 remains stationary. The rotation of the screw is achieved either by switching the motor or by using a motor which can be intermittently stalled as the load comes on the screw. Since the bloom will be sheared before the cutters meet, a limit switch 74 is positioned in front of the stationary cutter 24 and is actuated by the cutter block 22. The screw 54 is then continuously rotated in reverse to withdraw the cutter. In a modification the movable cutter block is directly attached to the driver block and the co-operating cutter is intermittently advanced by a screw mechanism similar to that described above. An extrusion press, Fig. 8 (not shown), has the ram moved by a mechanism as shown in Figs. 1 and 2 and has one or more parallel rams. An hydraulic intensifier has the ram driven by similar means, Fig. 9 (not shown). A forming press, Figs. 10 and 11 (not shown), is similar to the shear, but has the shearing tools replaced by a punch and die assembly. A portable hand-operated shear for cutting bars has a crank handle for rotating the worm 40 which drives the worm wheel 39. The screw 54 is rotated through reduction gears by a knurled disc the edge of which projects through the shear casing. Alternatively the worm shaft can be motor driven and the screw driven through a clutch, Figs. 12 and 13 (not shown). Lifting table.-The shear 10 moves with the bloom as it is cutting and for this purpose is mounted on a table 112 which is raised by two screw jacks 128. Each jack comprises a screw which is secured to the underside of the table and which passes through a worm gear 130 with a central threaded hole. The worm gears are driven in unison by two worms on a common shaft 134 which is driven by a motor 136. Each screw jack is hollow and is slidably sealed to a stud 148 to form therewith an hydraulic piston and cylinder assembly. Pressure fluid is supplied through a conduit 156 and passes through a central bore in the stud to the space 154 so that 90% of the weight of the shear is counter-balanced by the hydraulic thrust. The lifting table can also be provided for the extrusion press.