| 摘要 |
A focus control device to adjust a camera lens having a rotational input device 1, a variable gear ratio means 10 and a rotational output means. The gear ratio means may be a V-belt (14, fig 5) that may be infinitely variable and have two pairs of two conical rollers (12 & 13, fig 5). Each pair of conical rollers may be located on a shaft (5 & 8, fig 5) with the smallest radii facing one another and be pulled together by a resilient spring. The device may have position indicators 3, stop elements and a drag element 9. The drag element may provide an adjustable resistance in the form of frictional lubrication to the rotational movement between the input device and variable gear ratio means. In a second independent aspect, a focus control device to adjust a camera lens having a rotational input device, a gear ratio means and a rotational output means are claimed. |
