GB807760A - Improvements in or relating to power presses - Google Patents

Abstract

807,760. Mechanical presses. GOLDING, W. F. June 22, 1956 [June 24, 1955], No. 18401/55. Class 87(2). The movable platen 6 of a power press with a fixed platen 3, Fig. 1, is reciprocated by at least two operating shafts 53, 103 connected to the movable platen by cranks and toggle linkages 59, 109 and geared together by gear wheels 66, 116, the operating shafts being each driven from a shaft through individual slippermitting drive means. The drive between the shaft 7, Fig. 3, and the shaft 53 includes a clutch 20 comprising a driving member 21 splined to the shaft 7 and axially movable thereon and a driven member 23 journalled on the shaft 7, 21 and 23 having inter-engaging teeth 22, 24 so shaped, Fig. 4, that the teeth of the driving member tend to ride up on those of the driven member but are kept in engagement by a spring 26. The pressure of the spring is adjustable by a nut 29 which has teeth 32 meshing with a gear wheel 33 which can be turned by a shaft 34 formed with a square end 35. As the nut 29 moves along the shaft 7 the gears 32, 33 are kept in engagement by shroud plates 36 which cover the meshing teeth and in consequence of which the shaft 34 also moves axially, enabling annular indicia 37 on the shaft 34 to indicate the amount of adjustment. A latch 39 engages serrations 38 on the shaft to lock it in position. The slip-permitting drive between the shafts 7 and 103 is of similar construction with similar adjustment means. The toggle linkage 59 is operated from the shaft 53 by connecting rods 58 between crank pins 56 and pivot pins 64 and in Fig. 1 is shown in the straightened position where it has raised the front of the platen 6 to the limit of its height. The toggle linkage. 109, operated from the shaft 103 to raise the rear of the platen, is of similar construction. The press is driven through a wheel 12 which normally is electromagnetically connected to a driven wheel 13 on the shaft 7. Worms 51, 101 freely journalled on the shaft 7 drive the gear wheels 53, 103 which being in mesh, do not allow the platen 6 to tilt under uneven loading. Overload at either end of the press causes overriding of the teeth of the clutch 20 and the corresponding clutch 70 against their respective springs and these axial movements operate levers 46, 96 which trip switches 49, 99 before the teeth are completely out of engagement. The switches are connected in series and the tripping of either therefore breaks the electromagnetic connection between the wheels 12, 13 and makes electromagnetic connection between the wheel 13 and a brake member 14.