| 摘要 |
A tire changing machine for breaking tire beads on a wheel rim having a drop center is disclosed. The machine includes a bead breaker mechanism including upper and lower bead breaking shoes, driving levers for each of the bead breaking shoes, and horizontally and vertically adjustable mechanism for positioning the upper bead breaker, which mechanism is frictionally locked where manually adjusted. The tire changing machine also includes a rack and pinion drive arrangement for centrally located rotating tire tool driving post. The rack is driven by the upper bead breaking drive lever. Dual power cylinders are provided, one to drive the lower bead breaker drive lever and one to drive the upper bead breaker drive lever. The drive levers are driven bi-directionally by their respective cylinders. The center post is also driven bi-directionally by the upper bead breaker power cylinder. The mechanism also includes levers and pivots appropriately attached to the upper bead breaking mechanism for guiding the leading edge of the upper bead breaker through a locus inwardly toward the bead of a tire and therefore toward the drop center of a wheel rim on which the tire is mounted. The machine is particularly useful for changing tires on magnesium and other brittle alloy wheel rims while avoiding rim damage. |
