摘要 |
A fluid pressure-operated friction clutch is provided with a piston operating within a pressure chamber and constituted by two piston members having respective return springs of different strengths so that the pressure chamber can be opened to the atmosphere through a small escape passageway by the advance movement of one piston member whereafter the passageway is closed by the relative movement of the other piston member, whereby the piston which is coupled to frictional clutch plates applies a weak initial force to engage the plates without shock and a subsequent strong force to fully engage the clutch plates.
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