GB784110A - An electrically driven portable machine for sewing up bags or sacks - Google Patents

Abstract

784,110. Sewing machines. UNION SPECIAL MASCHINENFABRIK GES. Oct. 20. 1955 [Oct. 21, 1954]. No. 29952/55: Class 112 A portable machine for sewing up bags or sacks with single or two-thread chain stitching is driven by an electric motor 9, Fig. 1, detachably mounted, as shown by a bayonet joint, on the machine casing 1, which is made in two halves. The motor is provided with a handle 102 having lugs 93 adapted to carry a shoulder sling 94. A pinion on the motor shaft drives spur wheels 15, 16 operating respectively on adjustable crank shaft 19 for actuating upper and lower feed devices and a presser device and a double throw crank shaft 18 for actuating the needle-carrying lever 28 and the shaft 17 carrying the looper 21. The centres of the pinion and spur wheels lie on a line making an angle of 45 degrees with the axis of the shaft 17. Stitch forming devices. The lever 28. which is mounted on a bush 30. Fig. 8, for oscillation in bearings 29, carries at one end a curved needle 20. The other end of the lever is bifurcated to form arms 28b. 28c. The arm 28b is coupled by a link 26 to the crank pin 18a. The arm 28c is coupled by a link 31, Fig. 6, lever 34 and link 36 to a collar 39, Fig. 4, secured to the looper actuating shaft 17 and effects reciprocation thereof. Oscillation of shaft 17 is effected by crank pin 18b through a link 43 coupling the pin to a bridge piece 41 freely mounted on the shaft and slotted to engage a tongue 40 on the collar 39. The needle arm 28, Fig. 1, is provided with two needle-thread withdrawing stirrups 98, 99 oscillating on opposite sides of a stationary eyelet 96. The needle-thread N passes from the spool to the needle over guide 91, tensioning device 98b, eyelet 100, stirrup 99, eyelet 96, and stirrup 98. A withdrawal stirrup 97c for the looper thread G is also provided on the needle arm. Feeding work. The upper feeding device 23, Fig. 5, is arranged on a carrier 62 secured to a shaft 57, Fig. 6, mounted in lugs on a lever arm 60 secured to a hollow shaft 61 arranged co-axially within the bush 30 carrying the needle arm. The lower feeding device 24 is secured to a carrier 69 integral with a bush 50. Oscillation of the devices 23 24 is effected by crank 19 through a link 45 coupled to an arm 47 on a bridge 48. Fig. 4, arranged for free oscillation about the axis of the looper actuating shaft 17. One end of the bridge encircles and is clamped to the bush 50. A second arm 52 on the bridge is connected bv a link 54 to a lever arm 56 secured to the shaft 57 Work holding devices. The presser device 22 is secured to a lever arm 63 freely oscillatable about the hollow shaft 61. The alternate lifting of the device 22 and the feeding device 23 is effected from the needle arm 28 through a link 65. Fig. 6. pivoted to the arm and to the arm 66a of a bell crank lever pivoted at 60a to the lever 60. The other arm 66b of the bell crank lever carries a pin 66c engaging a groove in the lever arm 63. The lever 60 is variably loaded by a leaf spring 67 secured to the hood 68. A resiliently mounted linking tongue 70 co-operates with the stitch plate 80 and presser device 22 to urge the formed chain stitching constantly against the feeding device 23 to ensure that both ends of the seam are reliably secured by overhanging stitch formations. Severing work. A stationary knife 74, Fig. 7, adjustably mounted on a support 73 and a co-operating knife 75 mounted on an oscillatable arm 76 are arranged under the stitch plate 80. The arm 76 is arranged on a shaft 76a provided with a second arm 78 engaged by a fork 79 integral with the bush 50 which is clamped to the bridge 48 which is oscillated by crank 19. Spool holders. The spools 85. Fig. 1. are arranged between frusto-conical plates 86a, 89 interconnected by bars 86 threaded through the spools and secured by screws 88 to a supporting plate 83 fixed by screws to the machine casing 1.