| 摘要 |
1,190,318. Rollers; feeding sheets. D. O'RIODAIN. 13 Aug., 1968 [18 Aug., 1967], No. 38723/68. Heading B8R. [Also in Division F2] A composite compressible roller, for use in a machine handling sheets of polystyrene ceiling or wall tiles, comprises a cylinder 3 of foamed polyurethane surrounding and fast with an internal hollow steel shaft 2 which is supported on and rotatable with a coaxial solid steel centre shaft 1, the composite roller having a diameter which is approximately three times the diameter of the internal hollow shaft 2. The foamed polyurethane has a density of 40 kilograms per cubic metre, a degree of compression equal to 25% of the uncompressed thickness of the material under an applied pressure of 18À3 pounds per square inch, and a tensile strength of 25 pounds per square inch. The density may be such that an applied pressure in the range of 15 to 30 pounds per square inch will achieve a compressibility of 25%. Power driven pairs of such rollers 10, 11 are used in a machine for feeding sheets of foamed polystyrene via guide tracks 13, 14 to and from a cutting and/or marking cylinder 12 therebetween, the polystyrene sheets being individually fed from a stack 16 to the rollers 10 by a further similar composite roller 15 provided at its periphery along all or a portion of its cylindrical length with a segment 18 of foamed polyurethane, the segment 18 engaging the underneath surface of the lowermost sheet of the stock 16 and removing it therefrom to a guide 17 for collection by the rollers 10 for feeding to the cutting and marking cylinder 12. The diameter and speed of the rollers 10, 11 is the same, but the centre spacing of outlet rollers 11 is greater than that of the inlet rollers 10 and both centre spacings are less than the diameter of the rollers whereby the difference in effective roller radius, i.e. nip, contacting the polystyrene tile sheets provides a greater effective surface speed at the rollers 11 relative to the rollers 10 whereby the tile sheets are maintained under tension to avoid creasing thereof. |
