Patent GB-1467071-A (GB)
Title: Tyre changing machines
IPC: B60B30/06
Filed: 1974-01-30
Abstract: 1467071 Tyre changing machines MAGNUM AUTOMOTIVE EQUIPMENT Inc 30 Jan 1974 [30 Jan 1973 (6)] 04384/74 Heading B7C A tyre changing machine comprises upper and lower bead breakers 54, 55 operable by a single power unit 60, and a further power unit 205 for effecting clockwise and counterclockwise rotation of a centre post 47 and a tyre mount/demount lever 50 mounted on the post. Bead breakers.-The upper bead breaker includes an arm 74 integral with a collar 67 slidable along a post 66 pivoted on shaft 68 secured to cylinder 141 of the power unit 60, a tyre side wall engaging plate 93, a blade 58 integral with arms 76 connected to the arm 74 via links 80 and a pin 75 on the arms 76 slidable in a slot 79 in the arm 74, and a cover 101 having a wheel rim engaging portion 111, 112. Projections 116 on the blade 58 engage with notches 114 in the cover when the upper bead breaker is inoperative. The collar is locked in a selected position on the post 66 by a lock ring 120. Pivoting of the ring to a position abutting the lower surface 128 of the collar enables the collar to be moved along the post. The lower bead breaker comprises a blade 63 integral with arms 164 pivotally connected by shaft 145 to the piston-rod 143 of the unit 60. Guide arms 172 are pivoted at 173 to the machine frame and to the piston-rod by shaft 145, and are connected transversely of the machine by a bar 180 which in operation coacts with a notch 179 on a pivoted lever 175 to prevent further upward motion of the lower bead breaker. Springs 166 bias the blade 63 towards the centre post, and springs 152 bias the cylinder 141 and thus post 66 to the position illustrated in Fig. 5. The lever 175 can be pivoted to move the notch 179 out of the path of the bar 180 by manual shifting lever 186 to abut end 196 of slot 185. In operation the upper bead breaker is moved to a tyre and wheel rim engaging position (Fig. 6, not shown) and air (or hydraulic fluid) is introduced into space 149 within cylinder 141 upon operation of a foot pedal 154. This results in simultaneous or sequential movement of the breaker blades 58, 63. The blade 63 during its movement engages first the support 21 and then the wheel rim. Blade 58, however, follows the path 61 illustrated in Fig. 4, initially vertical movement of the post 66, due to shaft 68 moving in slots 137, results in vertical movement 276 of the blade 58 since projections 116 engage with notches 114, subsequently when projections 116 are free of the notches, due to movement of cover 101 relative to arms 74 and 76, the forces (123) (Fig. 9) acting against the blade cause the latter to slide on plate 93 radially of the wheel along path 277, and finally, as the arms 76 engage stops 87 and the pin 75 engages the forward end 92 of slot 79, the blade is constrained to again move vertically with the post. Such vertical movement is halted when the shift 68 engages the bottoms 275 of the slots 137 or when surface 109 of arm 74 engages a projection 110 on the cover 101. Release of the foot pedal causes atmospheric air to enter cylinder space 148 via a one-way valve 150 as springs 152, 166 return the unit 60 to the state of Fig. 5 during advance of the piston 147, air in space 148 is exhausted via the piston-rod opening. Centre post rotation is effected by a pneumatically (or hydraulically) operated power unit 205 and a rack 210 connected with the pistonrod 224 of the unit and engaging with a pinion 203 fast with the centre post. Air is supplied to cylinder spaces 220, 221 via independently operable foot pedals 261, 262 and associated values 250, 251 to effect respectively advance and retraction of the piston. Dampers (212, 213) (Fig. 14, not shown) each comprising an oil-filled cylinder (241) and a piston (242) with a bleed hole (243) therein, are connected to the cylinder and the rack. Tyre lever 50 has a tyre mount head 51 wherein R and R<SP>1</SP> are preferably substantially equal; H and H<SP>1</SP> are substantially equal; α = 115 degrees; # = 75 degrees and W is substantially (3/5)W<SP>1</SP>.