Patent GB-789111-A (GB)
Title: Improvements in book stitching machine
IPC: B42B2/02
Filed: 1956-03-12
Abstract: 789,111. Sewing machines. SMYTH MANUFACTURING CO. March 12, 1956 [Nov. 21, 1955], No. 7692/56. Class 112 A book-sewing machine in which the stitching also serves to secure tapes D across the backs of the signatures A, comprises thread-cutting means located near the stitching position and near the entrance to a guideway 15 for the signatures, control means for causing operation of said thread-cutting means after the stitching of the last signature of a book, a horizontal bar 56 normally located above the paths of movement of said tapes to the stitching position, and means adapted to operate automatically in synchronism with said control means for effecting downward and upward movement of said bar after the stitching of said last signature to form spacing loops F in said tapes between said last signature and the next following signature. The signatures are conveyed in succession to the stitching position by a swing- ing saddle 16. The latter contains looper hooks 34 and awls 32 adapted to pierce the signature for the passage of threaded needles 20 carried by a reciprocable crosshead 17 and hooked looper needles journalled in the crosshead for oscillation by gearing 26, 28. The threads B are drawn from cops C. The tapes D are drawn from rolls E and pass between a fixed horizontal bar 54 and the movable horizontal bar 56 located just before and normally above the stitching position, bar 56 being suspended from links 57, 58 carried by arms 59, 60 swingable about an axis 61. The threadsevering means are as described in Specification 418,176 and comprise transversely movable parts of the presser-foot 12, said parts being moved immediately after the stitching of the last signature by means of a lever 46 to form thread loops, and the latter being severed by knife edges carried by said parts during the subsequent movement of the signature along the guideway 15. The signature is initially moved away from the stitching position by a bar 62 car-. ried by arms 66, 68 which swing about an axis 64, the signature then being held in position by rods 69 which descend through the presser foot, said rods being raised when saddle 16 moves a fresh signature to the stitching position. The feeding and stitching of a signature is effected during one revolution of a shaft 72. The latter carries a pair of control cams 74 and 122, adapted respectively to co-operate with rollers 80 and 126 carried by respective levers 76 and 124, both of which are pivoted at 78. The end of lever 76 is normally engaged by a latch 86 fixed to a shaft 88, whereby roller 80 is disconnected from cam 74. A treadle 92, pivoted at 94, has an extension 96 connected by a link 98 to an arm 100 fixed to shaft 88, whereby depression of the treadle swings latch 86 against the bias of springs 90, 102 out of engagement with lever 76; when a spring 84, acting on a link 82, connecting lever 76 to a lever 106 pivoted on a shaft 108, biases roller 80 into engagement with cam 74. When roller 80 passes over a cam lobe 74<SP>1</SP> lever 76 rises and falls, whereby a pawl 112 carried by lever 106 co-operates with a ratchet wheel 110 fixed to shaft 108 to move the latter counter-clockwise. A peripherallynotched wheel 114, carried by the ratchet wheel, co-operates with a spring-biased detent 116 to retain shaft 108 in the position to which it is moved by pawl 112. A multilobed cam, carried by shaft 108, is adapted, on each partial revolution of the latter, to oscillate a shaft 118, whereby lever 46, which is carried by shaft 118, operates the thread-severing means. Roller 126 is normally disconnected from cam 122 by the engagement with lever 76 of a screw 130 carried by lever 124. The latter is connected by a link 132 to one arm of a lever 134 pivoted at 136, the other arm being adjustably connected by a link 138 to arm 59. Lever 124 is biased towards cam 122 by springs 128 and 142, and the arrangement is such that when roller 80 passes over cam lobe 74<SP>1</SP>, roller 126 traverses a cam notch 122<SP>1</SP>, whereby lever 124 rises and falls to cause corresponding downward and upward movement of bar 56. The treadle is depressed by the operator just before the stitching. of the last signature of a book.