Patent GB-1360650-A (GB)
Title: Sewing machine
IPC: D05B69/22
Filed: 1971-12-30
Abstract: 1360650 Sewing machine BROTHER KOGYO KK 30 Dec 1971 [30 Dec 1970 31 Dec 1970] 60636/71 Heading D1G A sewing machine comprises an electric driving motor (92, Fig. 9 not shown) a manually depressible controller (8 Fig. 1 not shown) associated with motor speed control circuitry, a clutch 20 connecting the motor to the armshaft, a stop lever 50 mounted on the machine frame to engage, in operable position, with stop means stopping the arm-shaft at a particular angular position, and actuating means 36, 32, 46 which can move the lever 50 to an inoperative position during depression of the controller, in which position the lever remains when the controller is relaxed while the motor then drives the machine at a fixed low speed for, as described, two revolutions of the arm-shaft, whereafter the stop lever moves back to stop the machine with, in this case, the needle raised. Clutch mechanism (Fig. 6). A pulley member 14 driven by the motor is integral with, or keyed to, a collar 13 rotatable on the armshaft 12 and surrounded by a helical spring 20 itself surrounded by a sleeve 21 notched to permit the spring ends 20a, 20b to protrude therefrom, the end 20a being secured to a flange 17a on a collar 17 pinned to the arm shaft and supporting the hand-wheel 18. The end 20b also projects from the sleeve and may either abut the part 56 carried on the stop lever 50 to disengage the driving connection between 14 and 12 or, when stop lever 50 swings the part 56 clear of the path of end 20b, rotates with members 14 and 17 to drive the arm-shaft 12. The position of the end 20b with respect to the member 17 and shaft 12 determines the shaft-stopping position; in a modification (Figs. 18-22 not shown) the hand-wheel 18 is axially movable on pins (103, 104) against the action of springs (109, 110) to disengage a toothed plate (106) from the collar 17. This permits the hand-wheel to be re-orientated with the arm-shaft at a position 180 removed from the original position, allowing the machine to be stopped with the needle either raised from or, if so adjusted, in the work. The collar 17 is connected to the end 20a of the spring through curved links 80, 81 which permit the shaft 12 to be rotated by manual operation of the hand-wheel 18. Operation. The machine can operate in any one of three modes selected by an external knob 59; in the normal sewing mode the machine is started by depressing a foot controller (8) and on release the machine stops with the needle in a selected (raised) position, in a basting mode depression of the controller causes a single stretching motion, while in the third a bobbin winder operates at a speed selected by the controller position. For normal sewing knob 59 is turned to allow detent 68 to dispose shaft 60 and its cams 61-3 in the position shown in Fig. 2. Supporting lever 34 thereby takes an extreme anticlockwise position moving actuating member leftwards and lever 70 moves clockwise to disengage the bobbin winding drive wheel 78 from rotary member 14. On depression of the controller switch 88 closes to energise solenoid 36 which rocks lever 32 clockwise about its pivot 35 to rotate lever 40 causing its end 40a to engage with cam 63 to prevent movement of shaft 60 and knob 59. Switch operating member 29 moves down to close switch 30 controlling thyristor 91 to start the driving motor, and lever 50 rotates disengaging its end 56 from the free end of the clutch spring 20 and permitting transmission of the drive from motor to the sewing machine. Lug 32b rotates intermediate levers 44 and 46 to disengage point 46a from the outer, annular, groove on the face of rotary member 14. On release of the controller solenoid 36 is deenergised and levers 32, 40 and 50 return to their earlier positions but inter-engagement of portions 29c 46b and 50b prevent member 29 and lever 50 returning. Lever 44 is disengaged by lug 50b and rotates to enter the point 46a into the start of a spiral groove 14b in member 14 to be carried thereby, as 14 rotates, and rotate lever 46 clockwise until after two rotations of 14 portion 46b of lever 46 releases in turn lever 50, and member 29 to allow 56 to move into the path of the end of the clutch spring and disengage the drive with the needle in raised position and to allow switch 30 to open and stop the motor. For basting, knob 59 and shaft 60 are rotated counterclockwise through 45. Lever 34 rotates clockwise from its Fig. 2 position (Fig. 11 not shown) bringing pin 42 to the centre of hole 32d in lever 32. On depression of the controller solenoid 36 lever 32 moves clockwise causing as before 40a to lock the shaft 60, switch 30 to close, and 56b to disengage the clutch spring end, but as now only part of portion 52a engages stop lever 50 the portions 52a and 50a disengage before 32 completes its movement, stop lever 50 thus returning to engage spring 20 and disengage the drive so that a single stitch is made and the needle stopped in raised position. The provision of the part 56 pivoted to the end of an arm of lever 50 prevents the lever stopping the armshaft before one revolution has completed.  Bobbin winding. Knob 59 is rotated further through 45 (Figs. 13 and 16 not shown) when cam 62 allows a lever 70 to rotate anticlockwise to engage bobbin winding wheel 78 with member 14. Lever 34 is moved anticlockwise by its cam 61 to position the right hand end 32d of its slot adjacent pin 42. On energisation of the solenoid 36 portion 40a locks the shaft 60, switch 30 is closed and 14 rotates to wind the bobbin, the drive to the arm-shaft being disengaged.