Patent GB-424939-A (GB)
Title: Improvements in mechanism for removing the stems of tobacco leaves from the webs thereof
IPC: A24B5/02
Filed: 1933-12-02
Abstract: 424,939. Tobacco-stemming machines. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(International Cigar Machinery Co. ; 5520, 2nd Avenue, Brooklyn, New York, U.S.A.) Dec. 2, 1933, No. 23207/34. Divided out of 425,187. [Class 130] Mechanism for removing the stems of tobacco leaves from the webs comprises web holding and stem holding devices between which a leaf passes and which are arranged to pull the web and stem in different directions to tear them one from the other, as described in Specification 380,496, and mechanism operative to effect relative movement between these devices to provide different spacing between their operative portions during the passage of a leaf between them. The devices are separated during the passage of the tip of a leaf between them, then moved towards each other to enable the stem holding device to take hold of a stem, and separated during the tearing of the stem from the leaf. The leaves are delivered from suction opening or spreading chambers between endless belts or chains 132 and an endless belt 137 to a suction cylinder 143 rotating about a hollow drum connected to a source of suction, the leaf webs being held by suction until they are delivered upon a belt 160, and the stems being torn out by a gripper drum 145, as described in the Specification referred to. The suction drum and cylinder 143 are mounted on a shaft 147 supported on arms 148 carried by the main shaft 149 and oscillated by a cam 154 on a shaft 155, which is driven through spur gearing adjustable to vary the timing of the cam in accordance with the length of the leaves handled. Arms 157 on the shaft 149 carry rollers 158, 159 over which the belt 160 passes, and the tip of the web is prevented from following the cylinder 143 around by a rotary brush 168 carried by arms 166 on the shaft of the roller 158. Rollers or rods 146, 146<1> adapted to enter between the cylinder 143 and the gripper drum 145, and to engage between the web and the stem at the tearing point, are carried by arms 195 loose on the shaft 184 of the stripping drum and are actuated from a cam 205 on the shaft 155 through levers 202, 199 and links 201, 198. The rollers 146, 1461 have belt pulleys thereon which are driven by belt gearing from a separate motor, at a peripheral speed equal to that of the suction cylinder 143. In the position shown in Fig. 5, the leaf L delivered by the belts 132, 137 is carried by the rotation of the cylinder 143 into contact with the surface of the drum 145 and the stem S is gripped between fins 189<a> and the pins 191 of successive plungers 190 under the action of the cam 193, Fig. 3. When a sufficient length of stem has entered the groove of the drum 145 to be securely held, the cams 154, 205 cause the cylinder 143 to move away from the drum sufficiently to admit the roller 146, which is moved through the gap between the cylinder and drum into the position shown in Fig. 7, to facilitate tearing out the stem. The stem S is disengaged from the gripper drum by a star wheel 216 entering between the pins and fins of the drum. At the end of each cycle, the cam 154 again moves the cylinder 143 away from the drum 145 while the rollers 146, 146<1> are returned by the cam 205 to their original position shown in Fig. 5. To prevent the stem S from riding on the outer edge of a fin 189<a>, out of the range of the gripping pins 191, a fluted roller 219, Fig. 3, is reciprocated axially, through a distance of approximately the width of one groove of the drum 145 ; a plate 220 carrying bearings for the roller 219 is reciprocated by means of a connecting-rod 224 actuated by a crank-pin 225 on a shaft 226. In a modification, Fig. 8, only one stripping roller 146 is used and is held towards the cylinder 143 by a spring 206<1>, the cam 205<1> serving only to take up the pressure of this spring when the cylinder 143 is withdrawn from the drum 145 by a depression in the cam 1541. The cylinder 143 remains in this position until the thin end of the stem has passed the roller 146, and is then returned to allow the stem to be gripped by the pins &c. on the drum 145. The roller 146 is now held against the leaf on the cylinder 143 by the spring 2061 and stripping takes place. After a sufficient number of grippers have taken hold of the stem S, the cylinder 143 is moved by the cam 154<1> a small distance away from the drum 145, to prevent the cross veins from being engaged by the grippers of the drum, the roller 146 following the cylinder 143 under the action of the spring 206<1>. At the end of the stripping operation, the cam 205<1> lifts the roller 146 from the cylinder 143 and the cam 1541 moves the cylinder 143 away from the drum 145 to allow the next leaf to enter between them.