Patent GB-436158-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B15/00
Filed: 1934-04-06
Abstract: 436,158. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd., Belgrave Road, Leicester.-(United Shoe Machinery Corporation ; 140, Federal Street, Boston, U.S.A.) April 6, 1934, No. 10408. [Class 112] In a chain-stitching machine with a straight eye -pointed needle co-operating with a looper, means are provided for disconnecting the needle from the sewing shaft on stopping the machine, either with the needle in or out of the work. The starting and stopping clutch comprises a member 42, Fig. 10, on the shaft 32 engaging a member 44 on a short shaft 46 in a bearing 48 in the pulley 34. The member 44 is keyed to the pulley 34 by the rolls 50 and sockets 52. The clutch members are normally held apart by a spring 54. They are brought into operative engagement by an arm 60 pressing on the ball end 62 of the shaft 46. The arm 60 is rotated on the shaft 58 to operate the clutch by a starting treadle through suitable linkage. The straight eye-pointed needle 70 co-operates with a rotating looper 72 on the forward end of the sewing shaft 40. The needle 70 is secured to the needle bar 74 which is actuated from a crank 80 supported on the crank arm 82 of the sewing shaft 40. The needle driving connections from the crank 80 are disconnected when the machine is stopped. These connections comprise a bell-crank lever 84, Fig. 2, secured by a pin 86 to a rock shaft 88, operating the needle bar 74 by a link 90 pivoted to an adjustable bracket 92. A second bell-crank lever 94 is mounted coaxially with the bell-crank 84 and is adjustably secured by a split socket and bolt 96 to a sleeve 98 on the rock shaft 88. The rearward arm of the lever 94 is connected with the crank 80 by a link 100 so that this lever is given a continuous rocking movement by the shaft 40. During normal operation of the machine, the bell-crank levers 84, 94 are connected to move as a unit so as to drive the the needle by means of the slip clutch which normally connects the rock shaft 88 and sleeve 98. This clutch comprises a member 102 having a projection engaging a recess in a strongly spring-pressed member 106, Fig. 3. A latch 112 is provided to ensure the continuous driving relation between the bell-cranks 84, 94 during the relatively heavy strain of the downward stroke of the needle through the work. When the treadle is released to allow the clutch members 42, 44 to separate to stop the machine, the latch 112 is raised to disengage the bellcrank lever 84 from the lever 94 and the bellcrank lever 84 is locked against further movement by an arm 122 on a rock shaft 126. The arm 122 carries a pin 126 adapted to engage the tail piece 128 of the latch 112 to release it from the pin 116 on the lever 94. The arm 122 is operated from the starting and stopping treadle by a rod 132. The arm 122, Fig. 6, has two recesses 140, 142 adapted to engage the pivot pin 114 on the lever 84 at the top or bottom of the needle stroke respectively. A sliding latch 144, controlled by the operator from a knee lever operated by the rod 164, enables either of the recesses 140, 142 to be covered so as to stop the machine with the needle on the top or bottom of its stroke. Specification 392,580 is referred to.