GB1126549A - Improvements in and relating to the controlled delivery of yarn in tufting apparatus - Google Patents

Abstract

1,126,549. Programmed control. CALLAWAY MILLS CO. March 6, 1967 [March 7, 1966], No.10450/ 67. Heading G3N. [Also in Division D1] A predetermined pattern formed by yarn tufts of different lengths is produced in a multi-needle tufting machine by frictionally feeding yarn to each needle through successive time intervals during each tuft-forming cycle, and by selectively varying the number of said time intervals for each needle during successive cycles. As shown, yarns 56 are fed to hollow needles 22 reciprocated through moving backing fabric 27, and compressed air is blown through the needles as the latter penetrate the fabric to project the yarns in the form of tuft loops 33, the height of which is determined by the length of yarn fed to a needle during the tuft-forming cycle. Each yarn is frictionally engaged between a wheel 50 driven by a motor 40, and an idler wheel 53. Motor 40 is of the pulseresponsive type, the driving shaft of the motor rotating a predetermined amount in response to an electrical impulse applied to the motor. The diameter of pulley 50 is such that a single pulse feeds the yarn a distance equal to a backstitch 61 interconnecting adjacent tufts. The length of a tuft is determined by the number of pulses applied in a tuft-forming cycle additional to that pulse required for the formation of the backstitch. The pulses are generated by electronic control means and are applied to the motors 40 via a patch board 85. Initially, the information defining a tufted pattern 80 in terms of loops 33 of various heights is converted into punch cards 81 for input to a digital computer 82 programmed for the preparation of a pattern programme magnetic tape 83. The latter contains a series of binary coded characters, each of which is equivalent to a decimal number representing the relative height of a loop 33 in that group of loops 33 formed in a single cycle. Each series is followed by a similar series to complete the number of cycles required for a particular complete pattern 80. Electrical input for the control means is provided by a tape reader 84. Yarn feed for the backstitches is effected simultaneously when a rotary cam member 90 actuates a microswitch 97 just after the needles commence to descend. Yarn feed for loop formation commences simultaneously when member 90 actuates a microswitch 106 just after the needles penetrate the backing fabric. The control means responsive to the tape comprises a number of bi-stable elements and logic elements which provide pulse outputs numerically proportional to the binary coded characters. The patchboard enables two sides of a symmetrical pattern to be controlled from one binary coded character or a plurality of tufting machines from one tape.