Patent GB-1160203-A (GB)
Title: Improvements in or relating to Ziga-Zag Sewing Machines
IPC: D05B69/22
Filed: 1968-03-07
Abstract: 1,160,203. Controlling clutch/brake combinations. 7 March, 1968 [9 March, 1967], No. 11018/68. Heading F2L. [Also in Division D1] The needle bar 14 of a zig-zag sewing machine is vertically reciprocated via connections to the main shaft 3, and is carried by a frame 13 rigid with a horizontally-reciprocating bar 17 for imparting lateral movements to the needle 16. Shaft 3 carries three slip rings 4, 5, 6 engaged by respective brushes B. The outer rings 4, 6 are provided with respective insulating segments 8, 9 displaced at 180 degrees apart and so arranged that the needle is in its up and down positions when said segments engage the respective brushes. A switch 64, disposed above and adjacent bar 17, has two fixed blades 66, 67 and a movable blade 65 normally spring-biased into engagement with blade 66. A magnet 68, carried by bar 17, is so arranged that when the needle is in the right hand half of its lateral movement blade 65 engages blade 66, and when the needle is in the left hand half of its lateral movement blade 65 is attracted to engage blade 67. Shaft 3 is coupled by a belt 47 to an axially-slidable shaft 43 carrying a friction clutch disc 44 normally biased by a spring 41 against is disc 40. The latter is journalled on shaft 43 and is coupled by gearing 38, 39 to a shaft 36 journalling a pulley 35 provided with a magnet coil 48, and coupled by a belt 34 to one end of the shaft 30 of a motor 28. The other end of shaft 30 carries a disc 31. A friction disc 37, slidable on but keyed to shaft 36, is positioned between pulley 35 and a fixed brake disc 49 provided with a magnet coil 50. Coils 48, 50 are connected by leads 63, 62 to the contacts 53, 52 of a switch blade 54 controlled by a relay 51. Coils 48, 50 are also connected by a lead 92 to relay 51 and to one pole 58 of a rectifier 56. The other pole 57 is connected by a lead 61 to the brush B engaging slip ring 5. Blade 54 is connected by a lead 59 to lead 61. A lead 75 connects relay 51 via contacts 77, bridgable by a switch blade 76, to the brush B engaging slip ring 4. Lines 79, 81 connect line 75 via contacts 78, bridgable by the blade 76, to the brush B engaging slip ring 6. Line 61 is connected by a line 69 to blade 65. Blade 66 is connected by a line 70 to a switch contact 71. Blade 67 is connected by a line 72 to a switch contact 73. A movable switch blade 74 is connected to line 75. As shown, blade 76 bridges contacts 77, blade 74 engages contact 73 and disc 44 engages disc 40, whereby the machine is stopped with the needle down and in the right hand position. Segment 8 is then engaged with the respective brush B to de-energize relay 51, whereby blade 54 engages contact 52 to energize coil 50 for engaging disc 37 with brake disc 49. The machine is started by depressing a pedal connected by a lever 42 for shifting shaft 43 to engage disc 44 with disc 31, the machine then running at full speed. Relay 51 is also energized via slip ring 4, whereby blade 54 shifts to contact 53 to energize coil 48 and disc 37 thereby engages pulley 35 to drive disc 40 at slow speed. When said pedal is released, disc 44 re-engages disc 40 to drive shaft 3 slowly until segment 8 is engaged by the respective brush B. While the needle is in the left hand side of its lateral movement, segment 8 is short circuited via the interengaged blades 65, 67. When the needle moves to the right hand side of its lateral movement and blade 65 engages blade 66, relay 51 is de-energized and disc 37 engages brake disc 50 to stop the machine. When blade 74 is alternatively engaged with blade 71, the machine stops with the needle down and in the left hand position. When blade 76 alternatively bridges the contacts 78, the machine stops with the needle up and in any random lateral position. In a modification, switch 64 and magnet 68 are replaced by three slip rings similar to the slip rings 4, 5, 6, the insulating segments on the outer rings being disposed at 180 degrees apart and corresponding to the extreme left and right hand positions of the needle.