| 摘要 |
A four bar link is provided between a walled cargo area of a truck and a rig id rear cargo door. The effective length of the lower link of the four bar linkage i s longer than that of the upper link such that the motion of the door is generally up and over the top of the truck body. An eccentric cam is joined to the upper link with a tensione d spring extending around the cam such that the spring slackens as the door opens. Th e cam is configured so that, as the door is opened, the spring slackens more slowly initially then more quickly. This allows the door to be moved initially mostly outwardly before moving significantly upwardly and still be effectively counterbalanced throughout i ts motion. |
