Patent GB-480051-A (GB)
Title: Improvements in or relating to automatic work-feed devices in book or like stitching machines
IPC: B42B2/02
Filed: 1937-02-11
Abstract: 480,051. Book-stitching machines. COLDITZ, L. Feb. 11, 1937, No. 4139. Convention date, Feb. 28, 1936. [Class 112] In a signature-stitching machine the length of the feed step between stitchings is periodically varied by a travelling signature-clamping device actuated by a pivoted lever, the lever having its stroke varied by the pivot axis being periodically displaced and returned to give an additional component to the stroke, such displacement and return being automatically timed in accordance with the number of stitchings for a signature. Figs. 1 and 2 show front and side views of the machine while Fig. 3 shows the timing mechanism on an enlarged scale. Fig. 10 is a diagram showing a three page signature abutting on a stop 12, and it will be seen that the first feed step must be of length a but the second and third steps must be of length b. The normal feed steps b are obtained by movement of a lever 36, Fig. 1, driven from a continuously rotating cam drum 30 ; the large feed step a is obtained by the pivot axis of the lever 36 being moved out and back by a cam drum 42 which is clutched in only for the first of the three steps for each signature. The travelling clamping device comprises a carriage 15, Fig. 2, with an arm 15a providing an under jaw 16 which slides along a slot in the rear plate of the stitching saddle S ; the upper jaw 17 of the clamp is provided by a lever 18 which at appropriate times is raised by a bar 23 operated from a rotary cam 26. The carriage 15 is operated by the lever 36 the normal throw of which is manually adjusted by varying the pin connection 38 to the lever 35 operated by the continuously rotating cam drum 30. When the throw of lever 36 is amplified (by displacement of a slide 40 carrying the pivot axis of the lever) the carriage 15 moves sufficiently for a tappet 20 on the upper jaw 17 to effect a lifting of the stop 12 and the jaws then reach and grip the signature and on return movement of the carriage 15 the first stitching is effected at the sewing mechanism M. The next two throws of the lever 36 are normal and feed the signature for the second and third stitchings. A fresh signature placed on the saddle will not be fed until the next amplified throw of the lever 36. The timing mechanism comprises a pawl-driven ratchet wheel 55 with a lug 57 which after a certain number of forward steps butts on a lug 82 and so moves a timing plate 47 in the direction of the arrow c, Fig. 3, whereby a link 66 is moved to cause the clutching in of the cam drum 42 by which the slide 40 is moved out and back to give the amplified throw to the lever 36. The forward movement of the timing plate 47 when butted by the lug 57 lifts up by a cam 82a a back stop-pawl 58 so that the ratchet wheel 55 is released and rotates backward under spring action until the lug 57 on the wheel 55 butts on a radial plate 53 extending from an arm 49 of a member 48 adjustably fixed to the timing plate 47 ; the - further backward motion of the wheel 55 now moves the timing plate 47 back until the cam 82a allows the back stop-pawl 58 to drop and re-engage the ratchet wheel 55. It will be seen that the lug 57 of the ratchet wheel is now butting on the radial plate 53 and that the number of steps required for the lug to engage the lug 82 on the timing plate 47 is determined by the spacing of the plate 53 from the timing- plate lug 82, that is to say, by the point of connection of the plunger 50 of the member 48 on the numbered recesses 52 of the timing plate. Further it should be noted that the link 66 is moved back to the de-clutching condition. The clutch arrangement is shown in Figs. 5 and 6. Movement of the link 66 to the left raises a plunger 63 whereby a lateral projection 61 on a spindle 60 is released and allows the spindle to turn under the action of a spring 62. The spindle has an eccentric end portion which jams on the inner periphery of a ring 64 on a continuously rotating gear wheel 54 and thus the boss 59 and shaft 43 are clutched to such gear wheel. After the first revolution, i.e. the first stitching operation, the shaft 43 is declutched since the plunger 63 will have been returned to the position shown in Fig. 6. The clutching - in of the shaft 43 gives the amplified throw of the lever 36 as described above.