GB466520A - Improvements in apparatus for clamping sheets in a power cutting machine - Google Patents

Abstract

466,520. Clamping - mechanism for cutting - machines. THORNTON, A. A. (Seybold Machine Co.) Dec. 12, 1935, No. 34484. [Class 31 (i)] A clamping-mechanism for holding stacks of material in a guillotine machine includes a system of levers and springs which turn as a unit until the clamp engages the work when part of the system remains stationary and the remainder moves round a pivot thereon to apply pressure to the work. The system comprises a cam lever 22 which is rocked on a shaft 23 by an eccentric 16, an eccentric strap 16a and a connecting rod 18 and has a cam surface 22a including a notch 22c to co-operate with a roller 30e carried by a double bell-crank lever 30. The latter is pivoted on levers 31 loosely mounted on the shaft 23 by holes 31u, being normally held in the position shown in Fig. 2 by springs 31b bearing against washers 24 on the shaft 23. A shoe 33 co-operating with an arcuate track 34 is pivoted to the lower ends of the levers 31. Springs 27 mounted on rods 25 carried by the washers 24 on the shaft 23 bear against a bar 26 on the bell-crank 30 to hold the roller 30e up to the cam 22a. The lower ends of the bell-crank are connected by pins 38b and slots 30d with lower hinge members 38 which are pivoted at 37 to upper hinge members 36; the upper and lower hinge members are coupled together by rods 40 and are urged apart by powerful springs 42. The upper hinge members are connected by links 46, levers 48, 50 and pull rods 52 to the clamp. In operation, a treadle is depressed to start the driving shaft 10 and the lever system moves as a unit clockwise about the shaft 23 until the clamp engages the work ; then the springs 27 yield, the roller 30e rides out of the notch 22c, and the levers 31 move downwards against the springs 31b so that the shoe 33 is forced into engagement with the track 34. The bell-crank 30 then rocks about its pivot 35 which is now stationary and operates through the hinge members 36, 38, links 46, levers 48, 50 and pull rods 52 to clamp the work with a force depending on the springs 42.