Patent GB-573416-A (GB)
Title: Improvements in or relating to machines for cutting leaf tobacco and similar materials
IPC: A24B7/12
Filed: 1943-09-18
Abstract: 573,416. Cutting tobacco leaf &c. LEGG, Ltd., R., and SCHREIBER, P. Q. R. Sept. 18, 1943, No. 15360. [Class 5 (i)] [Also in Group XXIII] A rotary knife-assembly is mounted for to- and-fro movement as required between grinding mechanism and tobacco leaf-feeding apparatus. Converging belts 2, 3 feed the leaf to jaws 4, 5. The upper jaw is movable being mounted on a parallel linkage 7, 8 of which the pivots 9, 10 are set above and below the axis of the knife assembly, when this is in cutting position, thus keeping the movement of the jaw parallel to that of the knives. Hydraulic pressure from an oil-pump 59 acts on the belt 2 and jaw 4 to press downwardly on the leaf. Both belts are acted on by support rollers 49, 50, and at the ends remote from the cutting pass over rollers mounted in adjustable journals. Reversible movement is transmitted to the shaft 15 from an electric motor 46 through belt, bevel and worm-and-wheel gearing. The knife-assembly comprises blades 6 clamped in holders 88 secured to a drum 80, Fig. 5. The clamps 93 are tightened by rotation of eccentrics 90, and are formed with recesses 96 into which the cut tobacco passes and from which it is subsequently blown by laterally placed nozzles supplied through a pipe 146 from a pump 147. Knife adjustment is effected by pivoted levers 101, the ends 108 of which enter recesses in a hub 87 angularly movable relative to the surrounding drum 80 by means - of a set-screw engaging an end projection on the hub. The cutting edges of adjacent knives are separated by distances equal to, or slightly greater than the width of the opening between the jaws 4, 5, and the edges are inclined to cut the tobacco progressively. To permit to-and-fro movement between the cutting and grinding positions the bearing 113 of the knife assembly drums are mounted in slides 114, Fig. 8. A dog-clutch 117 operable by a handle 123 allows the journal of the drum to receive rotary motion from the source of power. Internal movement is effected by a handle 127 through bevel gearing 132, 142, Fig. 2, and internally-threaded sleeves 144 on shafts 145, Fig. 2, 8. The grinding wheel 150, rotated by a motor 160, is mounted on carriages 154, 165 for movement parallel to and at right angles to its axis. Transverse movement by means of a hand wheel 164 positions it with reference to an adjustable diamond dressing wheel. Longitudinal movement of the carriage 154 for the same purpose is effected by a hand wheel 151 acting on rack and pinion mechanism in the bed 153 and beneath the carriage 154. Reciprocating movement is imparted to carriage 154 from a shaft 175 carrying loose bevel wheels 180, 181 alternately connected to the shaft through dog clutches 182, 183. The bevel wheels are in gear with a wheel 203 on the shaft of the pinion engaging the rack beneath the carriage 154. The clutch operating arms are connected to a bar 196 with projections 197, 198 on opposite sides of a bell-crank lever 199. The other end of the ball-crank is notched to engage a spring-pressed plunger 206. Projections 204, 209 on the carriage 154 also engage the lever 199 and snap it over at the end of the travel thus changing the clutches and reversing the drive. The shaft 175 is driven from the motor 46 through worm-and-wheel gearing, a shaft 220 and clutch members 171, held disengaged during setting of the members prior to grinding by a cam 173. Progressive advancement of the knife drum during grinding is caused by movement of the plunger 206 during the snap-over action of the lever 199. The plunger is connected by links 213 to a lever 212 on the shaft of a ratchet wheel 126 adjacent to the handle by which the main movement of the drum from cutting to grinding position is effected. A pawl 210 on the lever 212 engages the ratchet wheel which is thus advanced with each movement of the plunger 206. A cam member 217 lifts the pawl when the gr'nding operation should be completed, thus halting the knife feeding movement. The cam 173 is then operated to open the clutch 171, and the motor 106 switched off. Specifications 573,427 and 573,428 are referred to.