| 摘要 |
A guide to align a cutting or routing tool along a straight line has a stationary support fixed relative to the work and has arm-like linkage between the support and a hand-held tool or instrument. A first end-member of the first parallelogram frame is pivoted to the stationary support, preferably in conjunction with an arcuate angle indicator. Pivoted to this first end-member is a first parallelogram frame consisting of a pair of equal, parallel, arm-members which are pivoted to a pair of tangent identical rollers of a diameter equal to the effective distance between pivot centers of the first end-member. Means, such as bands around the rollers, insure that they revolve in opposite directions the same amount and remain tangent as the first arms move in parallelism. Extending from the center of each roller is one of a second pair of equal, parallel arms of the second frame which are pivoted to a final end-member of the same effective length as the first and the common end-members. The rollers thus constitute an elbow joint for the arm-like device. The final end-member of the second frame is fixed to the tool or to a guide against which the tool or instrument is aligned. One angle of movement of the first arm-members relative to their fixed end results in two angles of movement of the second arm-pair relative to the coupling mechanism. With the first end-member held in constant alignment to the work, movement of the tool or instrument is restricted to a predetermined straight line.
|
