| 摘要 |
A jack comprises a main frame device, an extensible rod device and two wheels. The main frame device has an upright pipe, a driving rod connected to the upright pipe, a reinforced plate connected to the driving rod and the upright pipe, an upper rod inserted in the upright pipe, and an upper block mounted on the upper rod. The extensible rod device has an outer pipe, a middle pipe inserted in the outer pipe, and an inner pipe inserted in the middle pipe. An inserted end of the driving rod is inserted in a lower end of the outer pipe. Two wheels are fastened on the upright pipe pivotally.
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