| 摘要 |
<p>1,113,125. Yarn-joining apparatus for ring- spinning machines. R. ESCURSELL-PRAT. 8 July, 1965 [9 July, 1964], No. 29096/65. Addition to 908,507. Heading DID. In the yarn-joining apparatus of the parent specification of the yarn-joining and auxiliary elements, at least the extractor is mounted on a vertically reciprocable platform raised or lowered by an auxiliary motor controlled by a detector on the platform which can make contact with the ring-rail as the latter reciprocates during the joining operation, which is initiated on detection of a break in the yarn between the traveller and the drafting rollers. Means are also provided for forming a tensioned length of thread from the broken end. When a break is detected, the vertically-reciprocable platform 45 is controlled by a detector 150 (see below) and carries an extractor mouthpiece 85; a device 48 for moving the traveller to a position convenient for rethreading; and a lever 180 which acts to re-thread the broken end through the upper thread-guide. A lever 26 on a stationary platform 30 serves to raise the yarn to a position where it can be united with the roving issuing from the drafting rollers. There is also a device for back-rotating the spindle to unwind a piecing length, a control being provided to prevent the operation of the thread joining mechanism, when the ring rail is in a position which prevents the movement of the device toward the base of the spindle. Movement of platform 45 (Fig. 1) is controlled by a detector 150 engaging the ring rail and -which is spring mounted for vertical movement relatively to the platform. The detector transmits indications to a clutch and a motor rotating a threaded spindle 153 having a nut 154 attached to the platform so that the platform is raised or lowered according to the direction of rotation of the spindle. The relative movement between the detector and the platform allows the latter to descend below the level determined by the detector for the mouthpiece to seize the piecing end. The detector when contacted by the ring rail, as the latter rises during a reciprocation, operates the clutch to connect the spindle to the continuously operating motor 152. The platform is thereby moved in the same direction as the ring-rail but more quickly, until the detector disengages and declutches the motor. The platform then remains stationary to await the ring rail, which continues to rise until it again contacts the detector, whereafter the cycle is repeated. When the ring rail descends during the same reciprocation, the same events occur in reverse, the descent of the ring rail changing over the connexions of the motor so that its direction is reversed. In an alternative arrangement, the motor is of the variable-speed self-regulating type and is supplied with information about the position of the platform by a detector so that the platform can follow the movement of the ring rail during the thread-joining operation. The back rotating device Fig. 14 comprises a disc 35 at the level of the spindle bases. When a break is detected the disc is normally advanced to engage and back-rotate the spindle to unwind a piecing length as described in the parent specification. In the present apparatus, a pivoted lever 179 is spring urged upwardly at 181 and is engaged by the ring rail in the first stages of the wind. The lever 179 cooperates with contacts 182, 183. Contact 182 makes operative the mechanism for the advance and return of the disc; contact 813 makes operative the thread joining mechanism. In the initial stage of the wind, the contact 182 is not operated until the ring rail, during the upward stroke of its reciprocation, has reached a position where the disc can advance without fouling the rail; by the time the ring rail performs its downward stroke, the disc will have advanced and retracted. Contact 183 is only operated when the ring rail is reciprocating in a zone when, on its downward stroke, it is clear of the advancing disc. The threading lever 108 is mounted in a frame 112 Fig. 13 which rises and falls with the platform 45. The platform has a rack 168 meshing a gear 167 connected to a cam 166 cooperating with a roller 165 fixed to the housing. The cam is shaped to move the housing and lever according to the changing position of the upper thread-guide 110 as the package is built. The lever is moved by a cam 169 on the fixed platen 30 driven by a shaft 24 which begins to rotate when a break is detected. The cam rotates a splined shaft 176 which is geared to the lever by bevels 177, 178. Arrangements for securing a tensioned length of thread from the broken end. This comprises a suction mouthpiece 85. This is on an end of a tube 84d, 84a, 84b, bent to form a curve and arranged to swivel when a break is detected about a union 83a carried by a fixed tube 84 connected at 86 telescopically or resiliently to a source of suction. In the bent part of the tubing between the mouthpiece and the union is a slit. When a break is detected, the source of suction is activated, and the platform 45 descends so that the mouthpiece seizes the end of the length unwound from the bobbin by the backrotating device. The yarn is thus drawn into the slitted portion of the tubes; when the end reaches the imperforate tube 84, the suction effect increases and the yarn is caused to pass out of the slit and extend under tension between the mouthpiece and the upper end of the slit across the curve of the tubing so that it can be acted upon by the levers 108 and 126. In an alternative arrangement, Figs. 3 and 4 not shown, the yarn-end seized by the mouthpiece is taken up by grippers mounted on an endless belt passing over pulleys one of which is driven. Operation of the device. When a break is detected the carriage stops, the various parts described are made operative, and the platform 45 begins to follow the movements of the ring-rail which continues to reciprocate. Subject to the control described with reference to Fig. 14, the disc 35 rotates the spindle to unwind a length of yarn from the bobbin and the mouthpiece descends inside the ring and seizes the end. As described above, a tensioned length of yarn is established; the traveller is positioned and rethreaded as described in the parent specification; the lever 26 moves the yarn to a position where it can be threaded through the upper guide 110 by the lever 108 and finally moves the end into contact with the roving issuing from the drafting rollers.</p> |
