| 摘要 |
<p>693,751. Loom picking mechanism. CESKOSLOVENSKE TEXTILNI ZAVODY NARODNI PODNIK, and SVATY, V. March 13, 1950 '[April 2, 1949; Dec. 16, 1949; Feb. 21, 1950; Feb. 25, 1950], No. 6217/50. Class 142(ii) A weft thread which is wound off in measured lengths from a stationary storage spool is inserted into a conventional warp shed in a weaving loom by means of an air jet surrounding and entraining said weft. The jet is produced by releasing a measured quantity of compressed air through a nozzle. In one embodiment (Fig. 1) weft thread 2 from a bobbin 1 is wound off in predetermined lengths by an apparatus frictionally driven by the loom main shaft 8 and having a pair of rollers 4, 5. The lower roller 4 has a rought surface and its circumference approximates to the reed width of the fabric. The thread then passes through a pair of tensioning jaws 10, 11 intermittently operated from a cam disc 15 and finally through an axial cavity in a valve body 17 of an air nozzle, which has a mouthpiece 19 and a blade wheel 20 giving rotation to an air jet. Air is fed through a throttle 22 to a chamber 21 which is adjustable in volume to operate one pick and thence through the mouthpiece 19 as the valve-body 17 is drawn back by a further cam disc 27 through the medium of a bell crank 24. At the same time the tensioning jaws 10, 11 are opened by the disc 15 and the issuing air entrains the air and carries it through the shed. In a modified form of nozzle a piston valve operated by a cam controls the supply of air for entraining the thread. The thread passes between two retracting rollers at least one of which is provided with a recess for releasing the thread at the moment of picking. A modified form of winding-off apparatus (Fig. 9) comprises a drum 51 on a shaft 52 geared to the loom mainshaft. Projections 65 on the drum carry the weft thread 74 round from a bobbin under a wheel 69 having a projection on its circumference for braking the thread at predetermined intervals as the thread is disengaged from the drum projections 65 by extensions 66 on a casting-off disc 63. The disc is driven at twice the speed of the drum by sun and planet gearing 58-61-62. Instead of a disc, a stationary ramp or a spring-biased lever may be used for casting off a required length of thread. A further embodiment of a winding off mechanism is shown in Fig. 14. Thread from a bobbin 96 is fed over a conical roller and under a braking wheel 95 and is interwoven with round ropes rotating on grooved disc 91, 92.</p> |
