| 摘要 |
A pitch control mechanism for a surface finishing machine. The machine inclueds a series of tiltable horizontal blades carried by a rotor and the blades are adapted to rotate in contact with and finish a concrete surface. The pitch control mechanism for tilting the blades includes an internally threaded sleeve located within the handle of the machine. The sleeve is operably connected through a cable to the blades and the sleeve is threaded to a rod or shaft. The engaged threads of the sleeve and the shaft have a pitch in the range of two to six threads per inch. The shaft is mounted for rotation in a manner such that a relatively small frictional resistance to rotation of the shaft occurs when the shaft is rotated in a direction to tilt the blades from a horizontal to a tilted position, but a substantially increased frictional resistance occurs when the blade is rotated in the opposite direction to thereby prevent free rotation of the shaft and unthreading of the threads due to the weight of the machine acting on the tilted blades.
|
