Realist, Inc.

Robert L Underberg

The telescope of the level-transit includes two mirrors at 45.degree. to the light path. A first mirror is fixed in the telescope housing by screws which thread into the mirror support to pull it tight against a datum surface established by a cover. The other mirror is mounted for pendulating action to automatically compensate the instrument for deviation from level within the design range. When the instrument is used as a transit the telescope is free to tilt up and down to measure vertical angles. At that time the pendulum is locked in center position. When the instrument is used as a level, the telescope is locked against elevation or depression. The locking mechanism actuates a device which frees the pendulum for operation to automatically compensate the level. The bottom of the pendulum weight has an inverted conical member fixed therein. The conical portion passes through an elongated hole in a leaf spring fixed in the telescope to flex about an axis transverse the mirror pivot axis. The hole is parallel to the pivot axis. The spring is self biased to engage the conical portion to center the weight. The telescope locking mechanism lifts the spring off the conical portion.

Level Transit

The optical sighting instrument uses the image of a floating bubble in a spirit level as a self-compensating index mark to indicate a reference line of sight at a given angle to the earth's normal surface.

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Mequon, WI, United States of America

Robert L Underberg