Patent GB-1003343-A (GB)
Title: Method and apparatus for making flexible conduit
Inventor: CADWALLADAR ALVIN AUGUSTUS
IPC: B29C48/21
Filed: 1961-12-01
Abstract: 1,003,343. Making conduits. TELEFLEX Inc. Dec. 1, 1961, No. 43148/61. Heading F2P. [Also in Division B3] An apparatus for making conduit comprises means for continuously advancing tubing 22 along a predetermined path of travel, means 38 operable in timed relationship with the advancing means and rotatable about the path of travel for supporting a plurality of spools 76 of wire, each of the spools including an axis of rotation extending in a plane disposed transversely of said path of travel, each spool axis being disposed at a substantially fixed angle with respect to the horizontal and for helically wrapping with a long lead a plurality of wires 24 in a substantially untwisted condition around the tubing 22, and means 42 disposed downstream of the path of travel from the wire wrapping means for applying a sheath 30 around the tubing and wires. As shown, the conduit comprises a flexible tube 22 of a plastic material such as polytetrafluoroethylene or polyethylene surrounded by wires 24 in abutting relationship with respect to each other and wound helically with a long lead so that the wires do not take a permanent set and are not bent during the winding operation beyond the elastic limit of the material of the wires. A cord or roving 26 made up of a plurality of threads are helically wound around the wires, and there is an external sheath 30 of a plastic such as nylon or polyethylene. The apparatus comprises a rotatable table or drum 34 for providing a continuous supply of tubing 22, or an extrusion machine, means 38 for applying the wires 24, a sizing die 40, means 41 for supplying and winding the threads 26, and means 42 for extruding the sheath 30. There are also cooling means 44 and traction means 46 for pulling the conduit through the apparatus; the finished conduit passes around pulleys 48, 50 and 52 to a storage drum 54 driven in timed relationship with the traction means 46. Wire supplying and applying means 38.- Axially spaced disc members 72, 74 fixedly mounted on a hollow shaft 58 carry spools of wire 76 mounted on shafts 78, 80 rotatable relative to the disc members. A disc member 92 also fixedly mounted on the shaft 58 is provided with slots 94, 96 in which are rotatably mounted pulleys 98, 100 for guiding the wires 24 which are directed by pulleys 108 through slots in the wall of the shaft 58 and to a guide plate 114 fixed in the shaft; some of the pulleys 108 and apertures in the plate 114 may accommodate more than one wire 24. To hold the shafts 78, 80 in fixed relationship in space while shaft 58 and members 72, 74 rotate, a sprocket fixed to non-rotatable tube 64 is connected by a chain 144 to a sprocket 150 secured to one of the shafts 78. The latter and the remaining shafts 78 carry sprockets 152 encircled by a chain 154. The shafts 78 rotate relative but oppositely to the shaft 58. A sprocket 156 carried by one of the shafts 78 is connected by a chain 158 to a sprocket 160 on one of the shafts 80 and this shaft and the other shafts 80 have also mounted thereon sprockets 162 encircled by a chain 164. To maintain a predetermined tension on the wires a spring biassed braking pad engages the peripheral edges of the flanges of the spools 76. The shaft 58 is driven by a chain 138 connected to a shaft 134 in turn driven by an electric motor 128. Sizing die.-The wires pass through the dies 40, Fig. 8, immediately after being laid upon the tubing 22. Cord applying means 41.-A tubular shaft 204 connected by a chain 210 to the motor 128 has fixed thereon a plate 214 carrying spindles 216 rotatably supporting bobbins 218 of thread 28. A plate 220 also fixed on the shaft is formed with apertures 222 aligned with the spindles 216 and have associated therewith thread-tensioning means 224 comprising pressure discs on a shaft and axially biased toward each other by springs, the thread passing between the discs. The tubing 22, and the wires 24 therearound, passes through a guide tube 240 and the threads 28 pass through apertures 246 in the shaft 204 to be wound on to the tubing 22 adjacent the end of the tube 240. The partially fabricated conduit passes through an extrusion head 248 for application of the sheath 30, the cooling means 44 comprising a trough 260 containing water and partially submerged in a trough 254. Conduit advancing or pulling means 46 comprises upper and lower endless belts 264, 266, consisting of hingedly connected blocks having conduit engaging grooves therein, encircling drive pulleys 268, 276 connected by gears 292, 294 and driven through a gearbox from the shaft 134. Specification 935,115 is referred to.