| 摘要 |
A stepless ratchet one way clutch mechanism as applied to an improved screwdriver tool is disclosed. A wheel (30) is rotationally fixed to a drive shaft (20). Two couplings (40) are rotatably mounted about the drive shaft (20) and extend away from the drive shaft (20). The wheel (30) is between the couplings (40). A lever (50) is pivotably attached to the couplings (40) at a pivot pin (60) between the couplings (40). The pivot pin (60) is beyond the wheel (30) outer diameter. When the lever (50) is rotated in relation to the couplings (40) an engaging chamfered edge (52) of the lever (50) presses the outer diameter surface of the wheel (30). The interface between the lever (50) and wheel (30) is of high friction. The interface has a "V" groove (32) on one of the lever (50) or wheel (30), and a "V" chamfer rib (57) on the other of the lever (50) or wheel (30). An elongated resilient spring (70) biases the pivot pin (60) either directly or through the lever (50) or coupling (40) to cause the lever (50) to rotate in relation to the couplings (40). When the lever (50) is held at a distal end while the pin (60) is biased, the wheel (30) is prevented from rotating in one or the other direction. The spring (70) includes a "Z" shaped portion such that a slide switch (80) causes a side to side bias on the spring (70).
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