Patent GB-829265-A (GB)
Title: Method of operating a board machine and a board machine for carrying the method intoeffect
Inventor: BEK STEEN JACOB
IPC: B28B1/42
Filed: 1958-03-11
Abstract: 829,265. Calendering and cutting fibrous sheets. SMIDTH & CO. A. S., F. L. March 11, 1958, No. 7817/58. Class 87(2).  Apparatus for making fibrous sheet material and for cutting it off at the right thickness comprises a rotating calendering roller provided with a groove in its surface extending along a line parallel with the axis and having a straight-edged cutter concealed in the groove, and operating mechanism which projects the cutter partly from the groove when the sheet on the calendering roller has attained a predetermined thickness so as to cut off the sheet and subsequently retracts the cutter. There are three link systems I, II and III, inside the hollow calendering roller and rotatable with it. Link system I comprises (1) a two-armed lever 9a, 9b pivoted at 10 to an end wall of the hollow roller 1 on which a sheet is formed, carrying rollers 11<SP>1</SP>, 1111 and biased to the Fig. 1 position by springs 131, 13<SP>1</SP>1 (2) a pair of bars forming a connecting rod 15 (3) a rod 18 pivoted at 17 to the connecting rod 15 at a short distance from its end. Link system II comprises (1) a two-armed activator 21a, 21b pivoted at 22 to the roller end and controlled by a toggle-joint spring device 24 to change from one extreme position to the other by snap action (2) a connecting rod 26 (3) a coupling member 29a, 29b freely rotatable on a rod 30 which extends from one end wall of the roller to the other and is itself rotatably mounted, the member 29b being pivoted at 19 to the other end of the rod 18 of the link system I. Link system III comprises a number of arms 32b rigidly connected to the rod 30 and each linked (rods 35, 36) to the cutter 7 lying in a groove in the roller surface and guided by guides 8, springs 34 biasing the cutter to the withdrawn position. The ends of the shaft 3 of the roller 1 are carried in the arms 44 (one shown in Fig. 5), of a fork rotatable about a shaft, not shown, so that the roller 1 rests by its weight against a roller 5 which drives a belt 4, the belt and layers of material 6, 37 being interposed between the two rollers, the former fed by the belt 4 and the latter calendered on the roller 1. In operation, Fig. 1, as the roller 1 rotates clockwise a stationary tripping member 12<SP>1</SP> strikes the roller 11<SP>1</SP> on the lever arm 9a and the lever 9a, 9b turns on its pivot 10 and, through the connecting rod 15, rotates the rod 18 about the pivot 19 until the roller 111 has ridden past the tripping member 12<SP>1</SP>, when the springs 13<SP>1</SP>, 13<SP>11</SP> restore the link system I to its original position, or, in case of failure of the springs, restoration is by a second trip member 12<SP>1</SP>1. Thus, as the initial layers are formed on the roller 1, the link system II is not operated. As the sheet thickens on the surface of the roller 1 the shaft 3 rises until a stationary tripping member 201 is met by the end of the arm 21a and the toggle device 24 snaps the member 21a, 21b over, resulting in the rod 26 turning the member 29a, 29b anti-clockwise and causing the rod 18 to pull the connecting rod 15 so that a pin 16 at its end engages a notch 33 in an arm 32a, link system II thus being brought into action and, in turn, link system III whereby the cutter 7 emerges from the guides 8 and cuts the sheet 38 of material. The link systems are restored during continued rotation of the roller 1 by the fixed tripping members 12<SP>1</SP>, 20<SP>1</SP>. The cut sheet passes over a roller 39 on to a conveyer belt 40. The position of the tripping member 20<SP>1</SP> is adjustable by movement of a sleeve 45 on a column 46, Fig. 5, which is graduated to indicate the thickness of the sheet which will be cut. The cutter 7 has a groove 51 along its edge, Fig. 7, the effect of which is to render more porous material at that point on the roller surface and so weaken it along the line of the groove to facilitate cutting. A piece 54 of canvas or rubber may be attached to the edge of the cutter to facilitate the removal of the cut sheet, or, for the same purpose, a bent metal wire may be welded to the ends of a cutter, capable of making a resilient movement away from the axis of the roller.