| 摘要 |
756,357. Feeding webs. BOWATERS DEVELOPMENT & RESEARCH, Ltd. July 2, 1954 [July 14, 1953], No. 19565/53. Class 100 (1). [Also in Group VIII] - In a web feeding machine comprising means for drawing the web from a supply and a pair of co-operating guillotine drums between which the web passes in the course of its travel and by which it is cut when a predetermined length has passed, the guillotine drums and the actuating mechanism therefor are so arranged that the web has normally free passage between the drums, but when the web is to be cut the drums are displaced out of their normal disposition to grip the web and to be rotated thereby until the web is cut, a positive drive being then applied to the drums to feed forward the web behind the cut for engagement with the web drawing means, after which feeding operation the drums are restored to their normal disposition. The web W travels from a reel 1 over a fixed reel 2, tensioning reel 3, fixed reel 4, between the guillotine. drums 5, 6 and over a glue roll 7 to a winding mandrel 8. Each of the drums 5, 6 comprise a polygonal frame 26 and a channelled member 27 in which is secured a knife 29, 30, the knife 30 being bolted directly to an angle bracket 28 and the knife 29 being made in two halves set slightly divergently from one another by means of bolts 31 and lock nuts 32. Two portions 33, 34 of the drum shells are pivoted at 35 and 36 to the frames 26 and are biased outwardly by springs 37 mounted in sleeves 38 having caps 39 engaging cradles 40 carried on the pivoted portions. The action of the springs is controlled by a threaded pin 41, passing through a yoke piece 42 keyed to the shaft 43 of the drum, and a lock nut 46. The remainder of each drum shell comprises segments 47 bolted to the frame 26 all but one segment 48 being covered with a layer of rubber. The drums are geared together and are driven from a motor 50 which, through a worm and worm gear continuously rotates a ratchet wheel 54 rotatably mounted on the shaft 55 of the drum 6, which co-operates with a pawl 58 controlled by a lever 57 and a fixed cam 61. Keyed to the shaft 55 is a plate 56 co-operating with a catch 60. Freely mounted on the shaft of the drum 5 is a disc formed with a gear segment 62 which co-operates with a toothed rack 67 spring biased for movement to the right, as seen in Fig. 1, on the release of a solenoid operated catch 77. The disc is also provided with a notch 63 co-operating with a catch 66 on a cam 65 keyed to the drum shaft 43. When it is desired to sever the web the solenoid-operated catch 77 is released thus causing rotation of the drum, through the action of the catch 66 in the direction shown by the arrows in Fig. 1 until the segments 33 grip the web, movement of the web continuing the rotation of the drums until the web is severed by the knives 29, 30. That portion of the web behind the cut is gripped by pivoted segments 34 and by this time the lever 57 has cleared the bulge of the cam plate 61 so that the pawl 58 is riding on the ratchet wheel 54. As soon as the speed of rotation of the drums has fallen to that of the ratchet wheel they will be driven by the motor 50 through the pawl 58 and ratchet 54. The drums continue to rotate until the pawl 58 and ratchet 54 are disengaged by the cam plate 61 by which time the raised portion 65 of the cam 64 has operated a lever 73 to restore the toothed rack 67 to its initial position. As the peripheral spread of the drums is slower than that at which the web is normally drawn the tensioning roll 3 is pulled downwardly under the action of a spring 18 thus causing, through linkage 12, 31 ... 15, rotation of a bell-crank lever 16 so that its free end contacts a collar 25 on a rod 24 causing movement thereof to rotate a lever 22 to tighten a braking belt 19 on the unwinding reel 1. Specifications 756,354, [Group XXVIII], 756,355 and 756,356, [Group VIII], are referred to. |
