| 摘要 |
<p>870,433. Supporting pneumatic tyres. FIRESTONE TIRE & RUBBER CO. Nov. 9, 1959 [Dec. 31, 1958], No. 37870/59. Class 144 (1). A chuck for inflatably supporting a pneumatic tyre to be worked on comprises a cylindrical base 2 which partially bridges the gap between the beads of the tyre and which has a flange 3 at one end for the air-tight support of one of the beads, a ring of radially-expansible and retractable segments 7 for the support, in their expanded position, of the other bead of the tyre, and an annular inflatable rubber air tube 20 carried in a recess in the end of the base 2 opposite the flange 3 whereby on inflation it completes the bridge between the tyre beads by contacting the toe of said other bead to force it against the segments 7, the tube 20 serving also to seal the chuck against escape of inflation air from the tyre. As shown, the base 2 is mounted on a stand 5, 6 to encircle a rocker-shaft 10 which extends upwardly through the stand and is rockable by a pneumatic motor 16 driving a crank 14. The shaft 10 carries an end disc 9 to which are pivoted one end of each of a series of links 8 the other ends of which are pivotally connected to the radially inner ends of the segments 7. The segments 7 are guided for radial sliding movement between upper and lower ring plates 23 and 51 which are secured to the end of base 2 opposite the flange 3 by screws 42, 43. Springs 26 oppose the rotation of shaft 10 to retract the segments 7 from their expanded position shown in Figs. 1 and 3. The ring plate 51, together with the recess in the base 2 defines a channel housing the tube 20, inflation of which is effected through a pipe 21, a channel 27 in a sleeve assembly surrounding the shaft 10, and a conduit 28. Likewise, an air inlet 29 provided in the base 2 for tyre inflation is fed via a pipe 31, a channel 34 and a conduit 35. In operation, to ensure that the upper tyre bead does not ride below the tube 20 on initial assembly of the tyre on the base 2, a centrally pivoted pawl 63, Fig. 3, is provided on the base 2 disposed so that, as the lower bead 61 slides thereover beyond its centre pivot 64, the pawl is rocked to raise its upper end 68 to serve as a stop preventing passage of the upper bead 62 beyond the tube 20.</p> |
