Patent GB-757319-A (GB)
Title: Improvements in circular looms
IPC: C08B3/20
Filed: 1953-02-03
Abstract: 757,319. Circular looms. OSTERREICHISCHE TEXTILMASCHINENFABRIK G. JOSEPHY'S ERBEN, and POLNAUER, F. F. Feb. 3, 1953 [Feb. 13, 1952], No. 2981/53. Class 142 (2). [Also in Group XXXV] A vertical circular loom has the warp supplied by beams at the bottom of the loom and shed by cam-operated horizontal heald frames, the fabric being wound (as a flattened tube) on a cloth beam at the top of the loom. The shuttles are driven (see Group XXXV) by a stator winding, which either feeds electric motors in the shuttles or propels them by inducing currents in plates or coils on the shuttles which interact with the field produced by the stator. Synchronism is maintained by varying the power received by the shuttles, and by braking them, in accordance with error voltages derived from coils on the shuttles co-operating either with coils revolving round the loom, or with stationary coils associated with timing switches to determine whether the shuttles pass the stationary coils early or late, the control circuits including relays, thyratrons and magnetic amplifiers. Letting-off, guiding and tensioning warp.- In one arrangement, two warp beams are employed, each supplying threads to half the circumference of the fabric. At both ends of each beam 40, a feeler roll 41, Fig. 4, adjusts the braking force applied by chains 54 to the ruffles of the beam in accordance with the amount of yarn remaining on the beam. The roll 41 carries a rack 42 meshing with a pinion 45 attached to a pulley 46 to which is secured a belt 51 connected to a stirrup 50 loaded by a weight (not shown). In another arrangement, six beams are disposed in hexagonal formation and are positively driven by worm drives, all the worms being coupled together by chain gearing. In this case, the warp 58 from each beam 40a, Fig. 12, passes over a roller 52a coaxial with the pivot 47b of a brake lever 47a to which a brake band 54a is attached; the warp then passes under a roller 46a whereby, when the tension increases, the lever 47a is raised against the action of a weight 50a to reduce the pull on the brake band. The warp threads are distributed round the loom by reed sections 100, Fig. 19, carrying guide ring segments 102, and a guide ring 103, the reed sections being adjustable in clamps 102a to equalize the thread tension round the loom. Warp stop motion.-Droppers 105, Fig. 19, located by a reed-like guide consisting of blades 1061 close a circuit between rings 107, 109 if a warp thread breaks. Shedding,-Heddle frames 62, Fig. 7, are carried by radial rods 60 operated by cam grooves 67 in the upper face of discs 61. The cam discs are split diametrically and are bolted together between unsplit end plates 72, 73 and keyed on the central shaft 1 of the loom. Each cam groove has a gap in its outer wall through which the follower roller can be withdrawn to enable the heddle frame and rod 60 to be removed from the loom, the gap being situated where the inner wall of the groove presses on the follower in normal operation. The undersides of the cam discs and of the top end plate 72 house circumferential rows of balls 75 to reduce friction on the rods 60. Alternatively, as shown in Fig. 8a, the balls 75<SP>1</SP> may be in the rods 60. To keep the heddle frames horizontal, the rods 60 are prevented from turning by flats on them engaging corresponding apertures in guides 11b, Fig. 7, which may be provided with balls 60b, Fig. 8e. The cams can be exchanged by removing some of the circle of pillars 11, Fig. 7, leaving sufficient in place to support the upper part of the loom.  Beat-up mechanism.-The weft is beaten up by vertically-sliding resilient fingers 80, Fig. 14, guided by spacers 88 and operated by a cam groove 81 in a rotating ring 82; as the fingers rise, they are deflected outwards by a conical surface 90 which causes them to enter the shed ; whilst a shuttle is passing, the fingers are in the position 80a. Alternatively, rigid fingers, sliding at an angle to the shed, may be used. Take-up mechanism.-At the top of the loom the fabric passes over a take-up roll driven by change gears, and is wound on a beam driven from the take-up roll through a slipping clutch to cater for the increasing effective diameter of the beam as it fills ; the tension at which the fabric is wound on is controllable by altering the friction in the clutch.