Patent GB-911337-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B19/00
Filed: 1960-10-28
Abstract: 911,337. Sewing-machines. NECCHI S.p.A. Oct. 28, 1960 [Dec. 31, 1959], No. 37115/60. Class 112. In a zig-zag sewing-machine comprising a plurality of cams, control members for the work feed and the needle swing, operative connections between the cams and the control members, and for each control member a handcontrol adapted to select a cam to actuate the operative connection associated with the respective control member, the cams are carried by a shaft which can be coupled by clutch means, controlled by one of said hand-controls, either to a continuously rotating shaft or to an intermittently rotating shaft. A vertical shaft 34, Fig. 15, has journalled thereon spaced gear-wheels 26 and 29. Gear 29 is driven continuously via a gear 27 from the main shaft 2, and has rigid therewith a cam 24 having uniformly-shaped lobes. Gear 94 is driven intermittently. A sleeve 95, splined to shaft 34, may be moved either upwardly to couple with gear 26 for driving shaft 34 continuously, or downwards to couple with gear 94 for driving shaft 34 intermittently. The upper end of shaft 34 carries field cams 33a and interchangeable cams 33c and 150. Stationary cam surfaces 33b of uniform radius are provided between cams 33a and 33c. The lower end of shaft 34 carries cams 51. A bar 8, Fig. 4, is pivoted at one end to the needle bar gate and is adjustably attached at its other end to a shoe 12 slidable in a horizontal groove 14 in a plate 15 pivoted at one end about vertical pins 17 between the arms of a forked member 16 pivoted to the machine frame about vertical pins 18, 19. A spring 25 biases member 16 to engage a follower pin 23 thereon with cam 24 to effect oscillation of member 16 about pins 18, 19. A bracket 31 slidable on a vertical shaft 30 carries an arm 29 formed with a lobe 28 engageable with plate 15, and also with a lobe 32 simultaneously engageable with any one of cams 33a, 33b or 33c to control the position of plate 15 about pins 17. A slot 35 in shoe 12 contains a pin 36 on an arm 37 fixed to a rotatable shaft 39. Another arm 38 on shaft 39 is connected by a link 40 to an arm 43 on a bracket 44 slidable on a vertical shaft 45. A helical groove 50 in shaft 45 is engaged by a tooth 49 in a bush 47 on an arm 46 having a forked end 48 slidably engaged with bracket 44, whereby rotation of shaft 45 engages arm 46 with any of the cams 51 to control the position of shoe 12 in groove 14, a spring 39 biasing arm 46 against the cover. When shoe 12 is aligned with pins 18, 19 at one end of groove 14 its movement is wholly controlled by plate 15, and when aligned with pins 17 at the other end of groove 14 its movement is wholly controlled by member 16. Movement of shoe 12 in groove 14 can also be effected manually by operation of a handle 63, Figs. 4, 24, on a member 61 fixed to shaft 30. A cam surface 60 on member 61 is engaged by a lobe 59 on a lever 56 pivoted at one end about a fixed pin 58 and connected at its other end to a bar 55 formed with a slot 54 engaged by a pin 53 on arm 37. Movement of handle 63 to the right serves to shift shoe 12 towards the pivots 17. In the extreme right-hand position of handle 63, shoe 12 is carried beyond pivots 17, whereby plate 15 swings to engage a stop-pin 184 on member 16. Simultaneously, arm 46 is separated from cams 51 and a lug 185 on member 61 engages bracket 31 to separate lobe 32 from cams 33. A lug 186 on member 61 also engages a lug 147 on a pivoted member 141 to move a cam follower lobe 148, Fig. 18, away from the axis of shaft 34, and a cam surface 187 on member 61 co-operates with a lobe 188 on one arm of a lever 189, pivoted on pin 58, to withdraw the end 191 of the other arm from engagement with a pair of toothed discs 192, 193 to free a pair of control knobs 131, 194 for rotation by hand. Disc 192 is rigid with a shaft 117 carrying the control knob 131 and a drum 113 formed with a helical groove 199. A lever 201, pivoted on a fixed pin 202, carries on one arm a pin 200 engaged with groove 199 and on the other arm a pin 203 engaged with a forked portion 204 of bracket 31. Rotation of knob 131 thereby serves to shift bracket 31 for engaging follower lobe 32 with any one of the cams 33. Disc 193 is rigid with a gear 197 and the control knob 194 journalled on shaft 117. Gear 197 meshes with a gear 198 on shaft 45. Rotation of knob 194 thereby serves to shift follower arm 46 into engagement with any one of the cams 51. Knob 131 is formed with a horizontal surface 132 from which rises a block 133. A lever 135, pivoted on a fixed pin 136, has a depending lug 134 adapted to engage either surface 132 or lug 133. Lever 135 also has an upstanding lug 137 which engages the undersurface of an arm 138 formed with the follower lobe 148. Arm 138 is rigid with a sleeve 140 pivoted on a fixed shaft 139 and slidable thereon between the arms of the forked member 141 also pivoted on shaft 139. A spring mounted within sleeve 140 biases the latter both downwardly, and also turnably to engage a lug 145 on sleeve 140 with a surface 146 on member 141. An arm 153, pivoted at 168, is spring-biased to engage a rounded lobe 152 thereon with a surface 151 on member 141 opposed to surface 146. The position of lobe 152 determines the rate and direction of work feed as described in Specification 911,338. Drum 113 is engaged at diametrically opposite points by the free ends of a pair of arms 111, 112, Figs. 15, 29, rigid with a block 108 journalled on shaft 45. Block 109 is connected by a spring-rod 107 to one arm of a U-shaped member 104 pivoted on a fixed pin 105. An arm 103, extending from member 104, has a forked end engaged between a pair of radial flanges 102 on sleeve 95. The arrangement is such that when the arms 111, 112 engage the cylindrical surface of drum 113, sleeve 95 occupies its lowermost position to couple shaft 34 with the intermittently driven gear 94. Lug 134 then engages surface 132, whereby sleeve 140 is in its lowermost position and follower lobe 148 is engaged with a fixed abutment 149. The work feed can be controlled only manually. When knob 131 is rotated to engage block 133 with lug 134, sleeve 140 is raised to engage lobe 148 with cam 150 for automatic control of the work feed. Simultaneously, arm 111 rides on to a projection 114 on drum 113, and arm 112 enters a recess (not shown) in drum 113, whereby member 104 is pivoted, and arm 103 shifts sleeve 95 into engagement with gear 26 for driving shaft 34 continuously. Gear 94 meshes with a gear on a shaft 71, Fig. 11. A drum 70, journalled on shaft 71, has an arm 69 which is biased by a spring 72 against an eccentric 68 on shaft 2. Drum 70 is thereby oscillated, and by means of a torsion spring 73 coiled around shaft 71 transmits intermittent unidirectional rotation to the latter. A split spring ring 78, Fig. 12, encircles shaft 71 and has ends 79 and 82 respectively engaging a spring-biased plunger 81 and a fixed abutment 83 to prevent back rotation of shaft 71. A ring 84 journalled on shaft 71 has an arm 85 biased by a spring 86 against an abutment 87, the position of which is manually adjustable. Another arm 91 on ring 84 passes through an arcuate slot 92 in drum 70. The position of arm 91 in relation to the position of the free end 77 of spring 73 may be adjusted via abutment 87 to vary the extent of the rotary steps imparted to shaft 71. A pair of scissors members pivoted on a fixed pin 119, Figs. 11, 15, have inner arms 120, 121 which are brought together to hold sleeve 95 in a mid position disengaged from gears 26 and 94, when the outer arms 122, 123 are spread apart by opposite lugs 124 on a pivoted, hand-operated shaft 125. A further lug 129 on shaft 125 may be engaged with a lug 130 on drum 70 to separate arm 69 from eccentric 68. A hand-operated lever is also provided, one arm of which is adapted to engage a lug 67, Fig. 4, on member 16 for swinging the latter to disengage follower pin 23 from cam 24. For visual indication of the pattern selected, a cylinder 206, Fig. 29, fixed to shaft 117, is divided into as many vertical sections as there are cams 51, and into as many horizontal sections as there are cams 33, to provide rectangles 206<1>, each of which bears a representation of one of the patterns producible. Cylinder 206 is loosely encircled by a ring 210 from which project lugs 209 embracing one end of follower arm 46. A rectangular space 211 formed in ring 209 and equal in size to a rectangle 206<1>, thereby travels in front of a vertical slot 208 in the machine frame, and the pattern enclosed by it is the one selected. Illuminating apparatus.-Cylinder 206 is made of transparent material, and its hollow interior tapers to an opening at the base. A lamp 212, enclosed by a shield 213, is situated at the base of the cylinder to illuminate the interior of the latter.