| 摘要 |
<p>A device (72) for measuring an angle between pivotally connected, intersecting sides,(40, 50) of a parallelogram (62) includes a grating (78) having a pattern (84) of parallel, straight grating lines (86) formed on a substrate (88) and a read head (80). The grating is mounted in a fixed position with respect to a first side (50) of the parallelogram. The read head includes a sensor (90) positioned for sensing displacement of the grating lines (86) in response to an angular change between the intersecting sides of the parallelogram and for generating a scale reading. The read head is mounted in a fixed position with respect to a second side (52) of the parallelogram that is parallel to the first side. In one embodiment, the grating includes a single pattern of grating lines and is used to measure an angular change relative to a reference angle. In a second embodiment, the grating includes first and second grating patterns and is used to measure an absolute value of the angle between the intersecting sides of the parallelogram. The precision angle measuring device (72) is particularly useful in coordinate measuring machines, but is not limited to such use.</p> |
