| 摘要 |
Each rocker arm (6) is so pre-tensioned to one side that when the chassis (1) lies parallel to the floor etc. in both loaded and unloaded conditions only the wheels (3,3') in the centre of the chassis adhere to the floor. The end of each rocker lever arm (4) pointing to the chassis ends has a wheel (2,2') or otherwise with a brake shoe as is also the upper part of the chassis centre wheels (3,3') so that one or other wheel is thrust against its shoe when the chassis is tipped. Alternatively, both wheels towards the chassis ends have brake shoes (10) to which either wheel is forced when its particular rocker arm is out of load. Two hanger arms (7,7') descending from the chassis-fitted boot plate serve to suspend the respective rockers (6,6') and the one-sided biassing spring (9,9') is fitted in between a tongue (8,8') rising off the rocker suspension point and an abutment on the chassis (1). This spring can come in coil or plate form or be gas-powered and has its own force adjuster.
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