| 摘要 |
PURPOSE:To prevent detachment of an impeller without degrading the easiness of attaching and detaching the impeller by providing between a rotary shaft and the impeller a securing member which is operated by the centrifugal force caused by the rotation of a pump. CONSTITUTION:An impeller detachment preventing device 7 includes a cylinder 8 attached to the outer periphery of the top end of a rotary shaft 3, a securing member consisting of such as a piston 9 and a spring 10, movable within the cylinder 8, and a spring clamping bolt 11. The impeller 2 has a recess 12 formed in opposed relation to the hollow bore of the cylinder 8 and adapted for receiving a part of the piston 9. During rotation of the impeller, the piston 9 moves against the tensile force of the spring 10 so that a part of the piston 9 is fitted into the recess 12 of the impeller 2. If a stud bolt is broken in such a fitting condition, the piston 9 serves as a key to prevent detachment of the impeller during its rotation.
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