GB1213565A - A device for stopping a sewing machine with its needle in a pre-determined upper position and for cutting the sewing threads - Google Patents

Abstract

1,213,565. Sewing machines. NECCHI S.p.A. 30 July, 1968 [29 Nov., 1967], No. 36345/68. Heading D1G. A device for stopping a sewing machine with the needle in a predetermined upper position and the sewing threads trimmed comprises needle position control discs 24, 25, 26, 27 on the machine shaft 20 which is coupled by a belt to a movable clutch disc 54 normally spring-biased against a rotary friction disc 41. The letter is coupled via reduction gearing and an electromagnetic clutch 52 and brake 53 to the consttently-revolving shaft of an electric motor driving a rotary friction disc 40. Disc 41 is coupled by a bell crank lever 57 to a treadle 60. As shown, the machine is stationary with the needle down and a brush 73 correspondingly contacting the insulating segment of disc 24, while relays 68, 69 are de-energised with their respective contacts 71, 77, 74 and 70, 76, 78 in the positions shown. When the toe of pedals 60 is partly depressed, disc 54 remains engaged with disc 41 and one arm of lever 57 closes a microswitch 65 to energise relay 68. Contact 74 then shifts to de-energise brake 53 and to energise clutch 52 and the machine runs at slow speed, relay 68 remaining energised via contact 70, the left hand contacts of a microswitch 36 and the contact 71. When the toe of treadle 60 is fully depressed, disc 54 is shifted into engagement with disc 40 for driving the machine at high speed. When the treadle is released, the machine runs at slow speed until brush 73 contacts the insulating segment of disc 24 to stop the machine. If a knee pad 39 is now depressed, microswkch 36 is actuated to close its right hand contacts to energise relay 68 via disc 75, whereby the machine runs slowly until the insulating segment of disc 25 rotates through 270 degrees to engage brush 75 to stop the machine with the needle raised. If it is desired to stop the machine with the needle raisd and simultaneously to sever the thread, pedal 60 is released when the machine is running at high speed and the heel of the pedal is then depressed, whereby lever 57 is deformed and its other arm closes microswitch 64. In consequence, when the machine has slowed down sufficiently, relay 69 is energised via a narrow conducting segment of disc 27. Relay 68 is then energised via contact 70 and disc 25, and relay 69 remains energised via the contact 76, while contact 78 energises solenoids 29 and 32 for respectively releasing thread tension and severing the thread. After energisation of solenoid 69, the machine rotates through 270 degrees until the insulating segment of disc 25 engages brush 75.