| 摘要 |
A cargo-receiving bed is pivotally mounted upon a wheeled undercarriage. An elongated actuator is telescopically and slidably mounted in the undercarriage and is hitched at its free end to a tractor. A lifting mechanism is connected to a portion of the actuator extending into the undercarriage to raise and lower the cargo bed. In one embodiment, the lifting mechanism comprises a pair of jointed arms each connected at one end to the cargo bed and at the other to the actuator. Suitable stop and guide members are provided to urge the arms into elevated positions as the actuator moves into the undercarriage and lowered positions as the actuator moves out of the undercarriage. An alternative lifting mechanism includes a lifting cam and a series of pivotally connected rods. Inward movement of the actuator causes the cam lifting surface to rotate upwardly against the underside of the cargo bed. Simultaneously, a pivotal connection between the rods rises and carries the bed further upwardly after the cam movement has run its course.
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