Patent GB-157619-A (GB)
Title: Improvements in or relating to pattern mechanism for looms for weaving terry fabrics
IPC: D03D27/08
Filed: 1919-12-01
Abstract: 157,619. British Northrop Loom Co., Ltd., (Northrop Loom Co.). Dec. 1, 1919. Pile-fabric looms; letting - off warps; take-up motions.-A pattern mechanism for looms for weaving Turkish towels is adapted to suspend the positive let-off during plain weaving, and to control the let-back and the beat-up; preferably it has also devices which enable the body of the towel to be woven of different lengths. The mechanism comprises a cam-wheel 55, Fig. 10, to the edge of which are attached removable cam strips 58, which control, in accordance with the design, levers 10, 11, and the let-off, let-back, and beat-up motions. Similar cam-strips A are attached to the edge of a ratchet-wheel 55, so as to lift, at intended times, the actuating-pawl 51, and thus to stop temporarily the rotation of the wheel 52; by the use of cam-strips 58 of various lengths, it is possible to carry the width of the plain and terry stripes at the ends of the towels, and to vary the length of the terry-woven body.of the towel. The actuator or lever 10 is connected by a wire 12 to the let-back, the cloth and warp being let back when the lever 10 is raised. When the lever 11 is raised, the wire 13 affects the beatup motion so that plain weaving is done; when the lever is down, the terry weave continues, the second wire 14 on the lever 11 controlling accordingly the let-off, shown in Fig. 7. In this device, the ground warp 32 is drawn from the beam 31, and the terry warp 15 runs under the rollers 16, 18, and over the let-off roller 17, to the harness; the roller 17 is actuated by a spring-pressed hookshaped pawl 20, which, by the operation of the pattern-mechanism, is drawn back by the wire 14 and levers 28, 29 so as to render ineffective the reciprocation of the rod 21 by the levers 22, 24 and the cam 26. The apparatus is driven by the main shaft 34, Fig. 1, of the loom, gearing 35, 38, 41, and a cam 44, against which a lever 46, 49 is pressed by a spring 48. In the mechanism shown, twenty-seven revolutions of the shaft 34 and the same number of picks are made for each movement of the lever 46, 49, upon the upper end of which is a pawl 51, shown also in Fig. 10, which slowly rotates the toothed wheel 52, the shaft 54, and the cam-wheel 55. These cams -consist of detachable sectors 56, 57, 58, 59, 60, Fig. 6, attached by their flanges to the edge of the wheel 55. The cams 56 ... 59 actuate the lever 11, and the cam 60 the lever 10. With the mechanism shown, the slow rotation of the wheel 55 causes the cam 56 to lift the lever 11, so that the wire 14 and pawl 20, Fig. 7, stop the let-off, and plain weaving takes place. When the lever 11 falls on the wheel 55 between the cams 56, 57, terry weaving follows for a space, forming a terry stripe following a plain stripe. Plain weaving continues while the lever 11 is upheld by the cams 57, 58, and is followed by terry and plain stripes due to the separated cam 59. This forms the adjacent ends of two towels; the terry body of the towel is then woven as the wheel 55 rotates until the cam 56 again reaches the lever 11. The saw-like cam 60 is set on the wheel 55 in such relationship to the teeth of the wheel 52 that the foot 67 of the lever 10 rests at the foot of each tooth of the cam; as the wheel rotates, the teeth raise the lever 10 and actuate the let-back, thus enabling the terry to be formed by the slack of the warp. To enable different lengths of towels to be formed, the ratchet-wheel 52 is fitted with a pawl-lifting device shown in Fig. 11, consisting of a curved plate A, one of a set of similar plates of different lengths masking some of the teeth of the wheel 52, and bolted adjustably to a flanged and toothed sector D on a plate G mounted adjacent to the wheel 52 on the spindle 54. During the normal working of the apparatus, the pawl 51 rotates the wheel 52 and an adjustable block I carries round the plate G until the pawl-lifter A engages with the pawl 51. The auxiliary pawl O then engages with the toothed sector D, and rotates it against the strain of a coiled spring M, the wheel 52 remaining idle. This continues until the sector D is carried beyond the action of the detent Q, which is mounted on the detent 74 of the wheel 52, and until the pawl lifter A passes beyond the pawl 51, which then again operates the wheel 52. During this time, varying with the length of the pawl-lifter A, the ordinary terry weaving of the body of the towel continues. The pawl-lifters are located on the wheel 52 at a point opposite to the position of the cams 57 - - - 59 so that the pawl 51 is not lifted except when the body of the towel is being woven. Friction washers 71 prevent too free a. movement of the wheels 52, 55.