GB1120136A - Improvements in warp knitting machines - Google Patents

Abstract

1,120,136. Knitting-machines. G. E. BOAST and R. WOOLLETT. 22 May, 1967 [24 May, 1966], No. 23045/66. Heading D1C. The speed of rotation of the warp beam 5 or bobbins of a warp machine is increased in response to the increase in tension of the yarns as the beam or bobbins is or gradually depleted of yarn during knitting. This ensures that the rate of delivery of the yarns remains substantially constant. The yarns 4 pass over a deflector bar 6 attached to a leaf spring 7 on the tension rail of the machine and any abnormal deflection of the bar 6 due to an excessive increase in tension caused by the failure of the beam to increase speed in relation to the decrease in the effective diameter of the yarn wound thereon causes the bar 6 to engage a bolt 10 secured resiliently to a lever 8. The lever 8 is consequently pivoted to cause its further end to be raised and actuate a switch 23 operating a clutch in the drive of the beam whereby its speed is increased. The further end of the lever when it is raised disengages from contact with a rod 27 under the control of a spring 28 and piston 18 in an oil filled cylinder whereby the current energizing an electromagnet 21 is cut off. The action of the rod 27 is to gradually follow the end of the lever 8 such that after a time delay the circuit is restored and the current again supplied to the electromagnet 21 with the result that the arm 8 is again pivoted and restored to its normal position. The switch 23 is thereby disengaged and the clutch ceases to function whereby the beam is now rotated at an increased speed. An over-centre device in the form of a notched disc 15 and spring loaded plunger 13. retains the lever 8 in its two pivoted positions until it is caused to be deflected to the other by the yarn tension or electromagnet. Alternatively an electronic time relay may be used instead of the hydraulic arrangement to control the electromagnet 21.