Patent GB-947153-A (GB)
Title: Improvements in the production of artificial slubbed filaments
Inventor: KENNEDY WILLIAM
IPC: D01D5/20
Filed: 1959-11-10
Abstract: 947,153. Producing slubbed artificial filaments. COURTAULDS Ltd. Nov. 9, 1960 [Nov. 10, 1959], No. 38031/59. Heading B5B. In a spinning machine for producing artificial slubbed filaments of the kind comprising at least one spinning head fed by a pump, a drive shaft fixedly connected to a worm to drive the pump through a right angle worm-wheel, means for displacing the drive shaft longitudinally so as to increase the pump speed and produce a slub and a fluid-operated device for displacing the drive shaft in the opposite longitudinal direction, there is means for supplying fluid to the fluidoperated device and means for regulating the flow of fluid from the device such that a low pressure is afforded in the fluid-operated device during the longitudinal displacement of the shaft in the direction for producing a slub and an increasing pressure is afforded during the opposite longitudinal displacement. As shown in the drawing, an hydraulic circuit for effecting the return of the pump drive-shaft on a spinning machine (not shown) comprises a pump P, a cylinder 2, a relief valve V, a solenoid-operated by-pass valve S in parallel with the relief valve V, and a reservoir R. The pump P delivers a continuous and constant feed of hydraulic liquid into the circuit and the relief valve V is set to open at a selected high pressure greater than that required at the end of the return stroke. The valve S is operated by a solenoid which is in electrical parallel with the solenoid operating a pneumatic valve (not shown) which causes the slubbing stroke. Within the cylinder 2 slides a piston 1 on a rod 3. The pump drive-shaft 4 is urged into contact with the piston rod 3 by a spring 5. In operation of the machine, the opening of the pneumatic valve to cause the slubbing stroke (which is from right to left in the drawing) is accompanied by opening of the valve S, with the result that the pressure in the cylinder 2 is able to drop to a very low figure, less even than that required to initiate the return stroke. When the pneumatic valve closes, the valve S also closes and the pressure in the cylinder 2 builds up. Once this pressure overcomes the opposing effect of the spring 5, the piston rod 3 and the drive shaft 4 begin the return stroke at a constant speed equal to the constant rate flow of hydraulic liquid into the cylinder. The continuing rise in pressure overcomes the increase in resistance to the return stroke resulting from the increased compression of the spring 5. After completion of the return stroke, the pressure in the hydraulic circuit will rise only until it reaches the value determined by the setting of the relief valve V, whereafter it is limited by the relief valve to that level until the reduction in pressure which occurs with the opening of the valve S at the beginning of the next slubbing stroke. When it is desired to avoid the production of " normal " denier sections completely, so that the filaments have only two deniers, namely those produced during the slubbing and return strokes respectively, it is ensured that the interslub length never exceeds that produced during the return stroke, i.e. the return stroke is never completed before the next slubbing stroke begins. In these circumstances the relief valve V normally never operates and its function is purely that of a safety valve against abnormal conditions. The relief valve may be omitted or replaced by a simple safety valve. When it is not desired to produce short slubs, the apparatus may be operated without using the pneumatic slubbing valve, both strokes of the drive shaft being controlled from the " hydraulic " end of the apparatus. Thus when the by-pass valve S is opened, the pressure of the spring 5 is sufficient to cause the slubbing stroke; when the valve S closes, the pump P produces the return stroke in the normal way. The production of a reduced denier portion due to the slowing down of the spinning pump speed below normal denier speed is minimised in the apparatus of the invention by making the return stroke as slow as is conveniently possible. Specification 773,781 is referred to.