Patent GB-858449-A (GB)
Title: A pneumatic device for reversing tubular fabric
IPC: D06H3/16
Filed: 1959-02-18
Abstract: 858,449. Sewing machines. LUCHI, V. Feb. 18, 1959 [Feb. 18, 1958; April 12, 1958; Nov. 24, 1958], No. 5541/59. Class 112 [Also in Group VIII] Means for turning tubular fabric inside out comprise a chamber adjacent to and at least partly surrounding the end of a pneumatic conduit, and means for creating an airstream directed radially outwards with respect to the mouth of the conduit and then, within the chamber, parallel to and around the outside of the conduit, whereby the leading portion of said fabric after pressing through the conduit and reaching the end thereof is forced open by the radial airstream, is reversed and is disposed around the conduit. As shown in Figs. 1, 2, 5, tubular fabric produced on a circular knitting machine in a chamber 3 is drawn by suction down a conduit 4 and is reversed in a chamber 7 surrounding the upturned end 4a of the conduit. The lower end of chamber 7 communicates via a grid 8 with a chamber 6 connected by a pipe 9 to a valve casing 10. The latter is formed with radial openings 17, 18, is connected to the pressure duct 21 and suction duct 22 of an air compressor 23, and contains a hollow, rotary valve body 11. The latter is operated by a lever 16 and may be turned either to connect the suction duct to pipe 9 and the pressure duct to aperture 17 or to connect the pressure duct to pipe 9 and the suction duct to aperture 18. The upper end of chamber 7 is closed by a cover 24 having a central aperture. Normally seated in the latter is a tubular member 27 having at its axis a streamlined core 28. Members 27, 28 are of light construction and are hinged at 26 on cover 24. A chamber 29 disposed over the latter is provided on its lower surface with a hinged door 30 operated by a lever 32. Levers 16 and 32 are respectively connected by links 38 and 37 to a member 35 the angular position of which is controlled by a cam drum 2. The arrangement is such that while the fabric tube is being knitted in chamber 3, door 30 is closed and suction is applied to pipe 9, whereby the fabric tube is tensioned downwardly. On completion of the knitting, door 30 is opened slightly, whereby air flows through the annular space between the members 27, 28 downwardly and outwardly over the end 4a, the suction in which is correspondingly reduced. The fabric tube travels along the conduit and on emerging from the end 4a is turned inside out by the downward current of air to surround the latter. Valve 11 is then turned to direct a blast of air into pipe 9 and door 30 is opened wide. Members 27, 28 thereupon swing open and the reversed fabric is blown through cover 24 and passes via door 30 into a collector 34. A pulsating effect may be produced in conduit 4, 4a during the reversing process by cyclically varying the slightly open position of door 30. Alternatively, as shown in Fig. 2, the axial position of member 28 may be varied to alter the area of the annular space between members 27 and 28. Member 28 is carried by a lever 40 pivoted at 26 and connected by a rod 41 to the core 42 of an electromagnet 43 which is arranged to be energised intermittently during the reversing process - to draw rod 41 downwardly against the action of a spring 44. In a modification, Fig. 6, lever 40 is connected to a rod 41a carrying a hollow piston 47 disposed in a cylinder 48 which may be put into communication, via a pipe 49, with pipe 9. Piston 47 is then drawn downwardly, against the action of a spring 50, till holes 47a in the piston register with holes 48a in the cylinder, when the vacuum in the latter is destroyed and the piston moves upwardly. In a further modification member 28 is fixed and the arrangement serves to vary the pressure in pipe 9. In the modified arrangement of Fig. 8 the upper end of a pneumatic conduit .53 is disposed in a rotatable needle cylinder 51 and the lower end is disposed in a fixed cylinder 54. The upper end of the latter is closed by a grid 56 and the lower end is closed by a hinged flap valve 69 formed with an eccentric aperture 69a. A fixed cylinder 58 surrounding cylinder 54 journals at its upper end in ball bearings 59a a sleeve 60 fixed to the conduit 53. The lower end of cylinder 58 communicates with a duct 62 which may be connected to a source either of suction or of pressure. A lug 64 on cylinder 51 engages a lug 63 projecting on conduit 53 to rotate the latter. It is stated that cylinder 51 and conduit 53 are relatively movable axially to effect or interrupt the rotation of conduit 53. A bell crank lever 65 pivoted at 66 on cylinder 58, is operated by a flexible cable 67 to engage the upper portion of sleeve 60 for braking the rotation of conduit 53. When suction is applied, the tube knitted in cylinder 51 is tensioned downwardly within conduit 53, and on leaving the needles travels downwardly and is turned inside out over the exterior of the lower end of conduit 53, the initial turning movement being assisted by the eccentric stream of air flowing upwardly through aperture 69a. On completion of the turning operation, pressure is applied to blow the fabric past the now open flap valve 69 into a collector 71. In a further modification, Fig. 14, a conduit 90 is rotatably mounted in a cylinder 96 communicating via a duct 97 with an air pressure-reversing valve 98. A cylinder 91, disposed around conduit 90, is formed at its upper end with a grid 91a, and is connected at its lower end by a conical union 92, formed with peripheral apertures, with a duct 93, the latter entering a collector 94 via a flap valve 95. Suction in duct 97 causes downward movement of a fabric tube in conduit 90 and reversal of the tube about the lower end`of the latter, the reversal being initially assisted by the eccentric upward flow of air through the apertures in union 92. Pressure applied to duct 97 effects stripping of the tube from conduit 90 and its discharge via the duct 93 and flap valve 95 into the collector 94. Fig. 15 shows an arrangement generally similar to that of Fig. 14, but modified in that the cylinder 101 containing the tube-reversing conduit 100, and the collector 105 are connected by respective ducts 108, 109 to a rotary valve 113 adapted to connect either of ducts 108 or 109 to a suction duct 112 and the other to the atmosphere. Suction applied to duct 108 causes reversal of a fabric tube drawn downwardly through conduit 100, and suction subsequently applied to duct 109 causes stripping of the tube and delivery of the latter via a duct 103 and flap valve 104 into the collector 105.