| 摘要 |
825,084. Pneumatic springs. JOHN BULL RUBBER CO. Ltd. Jan. 13, 1958 [Jan. 14, 1957], No. 1347/57. Class 108(3) [Also in Group XXVIII] A rubber hose for a pneumatic suspension for road vehicles having circumferential corrugations comprises as a reinforcement at least two layers of a cord fabric applied to a vulvanizable rubber tube, the fabric having been so cut on the bias and applied with opposing bias to the tube that the layers are stretched during formation of the corrugations when manufacturing the hose (see also Group XXVIII). The circumferential corrugations may be normal to the axis of the hose or may be helically disposed A greater number of layers of cord fabric than two provided in pairs may be used. The cord fabric is similar to the fabric used in the construction of pneumatic tyres and consists of warp cords with very weak weft threads lightly to hold the warp cords together. Preferably the fabric is calendered on both sides with a rubber sheet and is then cut on the bias and the two plies of composite fabric are applied with opposite bias to the vulcanizable inner tube. Instead of the above cord fabric there may be used a weftless cord fabric produced by passing a number of single warp cords in parallel relationship through a calendar to form a sheet of material comprising the cords between two layers of rubber. The warp and/or weft may be of natural or synthetic fibres or admixtures thereof e.g. of cotton, linen, rayon, nylon and so on. The vulcanizable inner tube may be wound or applied on the mandrel or a strip of vulcanizable rubber may be shaped around the mandrel to form the tube The bias angle may be about 25 degrees or about 30 degrees. In Fig. 3 the inner vulcanizable tube is shown at 11 and the cord fabric layers at 12, 13. Around the layers 12, 13 is an outer vulcanizable rubber tube 14 having regions of greater wall thickness as at 15. The inner tube may be provided with thicker regions instead of or in addition to those shown at 15. The inflatable tube of Fig. 1 is stretched axially so that its diameter is reduced and thereafter it is inserted into the inner tube 11 and the ridges 21 are brought to lie beneath the regions 15. The inflatable tube is then blown up to a pressure of say 10 lbs./ sq.-in. The valley portions between the regions 15 are held against diameteral expansion Thus the regions 15 are increased in diameter. Thereafter the assembly is introduced into a curing mould 25, Fig. 5. While in this mould the inflatable tube is subjected to a pressure of about 100 lbs./ sq. in. so that the tube is corrugated as indicated at 26. While the tube is subjected to pressure it is vulcanized in the usual manner. The corrugated hose may be reinforced by providing a plurality of rings which closely lie within the valleys between the corrugations.
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