GB819878A - Apparatus for separating tyre beads from wheel rim flanges - Google Patents

Abstract

819,878. Tyre bead cracking apparatus. DUNLOP RUBBER CO. Ltd. Aug. 29, 1957 (Aug. 31, 1956], No. 26624/56. Class 144 (1). A tyre bead cracking apparatus comprises a frame having two spaced parallel arms 7, 8 adjustably pivoted at one end to a base frame 1 and supporting therebetween a pair of pressure members 20, 21 which have relative axial movement and can be located coaxially on opposite sides of a pneumatic-tyred wheel, each member 20, 21 having an endless pressure ring 42 detachably secured thereto so that on relative approach movement of the members the rings contact the tyre on one or both sides to force the adjacent bead or beads from the associated rim flange. As shown the frame arms 7, 8 are connected at one end by a transverse tube 11 between brace plates 9, 10 and are pivoted at that end on pins 12 extending through lugs 13 at one end of the base frame 1. To adjust and hold the arms 7, 8 at the inclination necessary to provide the desired height of their free ends a set screw 15 screwed into a block 14 on a crossmember 4 of the base frame 1 bears against a pin 16 extending transversely through and from the tube 11, Fig. 2. The pressure members 20, 21 each comprise concentric rings 22, 23 connected together by equi-spaced spoke plates 24-28, the spokes 24 extending diametrically across both rings 22, 23. The pressure member 21 is rigidly secured to the arm 8, and the member 20 is carried on diametrically spaced rods 32 which slide in holes 33 in the arm 7. The spoke plates 25, 27 of each member are provided with a series of diametrically opposite pairs of holes 30 for the selective detachable attachment of a pressure ring 42 of the desired diameter, each ring 42 having a pair of opposed tapped holes 45 whereby the ring is clamped to the member by screws 46 extending through the appropriate pair of holes 30. The members 20, 21 have aligned axial holes 29 which align with holes in the arms 7, 8 to receive a slidable draw rod 19. The rod 19 is knurled at the end adjacent the arm 7 and has a collar 18 pinned thereto to engage non-rotatably with the member 20, the other end 53 of the rod being screw-threaded and extending outwardly through the arm 8. The draw rod is operated, to pull the member 20 towards the member 21, by a rachet-operated nut 54 on the end 53 of the rod, distance pieces 55 being provided for use according to the width of the wheel and tyre being operated on. The pressure rings 42 each comprise an axial flange 43 to sleeve snugly over a wheel rim edge and engage the tyre, and a radially inwardly projecting flange, which may be gapped to provide spaced webs 44, whereby the ring is secured to the associated member 20, 21. In use the arms 7, 8 are adjusted angularly to locate the members 20, 21 coaxially on opposite sides of the wheel, the rod 19 is then passed through the aligned holes in the arms 7, 8 and the members 20, 21, and through the wheel centre, and the nut 54 operated to cause the flanges 43 of the pressure rings to bear on opposite sides of the tyre. If one tyre bead is cracked before the other, the webs 44 of the effective ring 42 will abut the adjacent wheel rim edge so that pressure is then concentrated on the other tyre bead. In an alternative arrangement one of the rings 42 may be arranged to abut the wheel instead of the tyre to effect cracking of the beads one at a time.