Compass

Claim 1

A COMPASS COMPRISING A BODY MEMBER AND A GEAR RACK MEMBER MOUNTED FOR STRAIGHT LINE ADJUSTMENT MOVEMENT WITHIN SAID BODY MEMBER AND PROTRUDING ON EACH SIDE THEREOF, SAID BODY MEMBER INCLUDING GUIDING MEANS FOR MAINTAINING SAID GEAR RACK MEMBER IN ALIGNMENT THEREIN DURING SAID MOVEMENT, A PINION GEAR MOUNTED WITHIN SAID BODY MEMBER AND IN ENGAGEMENT WITH SAID GEAR RACK FOR CONTROLLING THE ADJUSTMENT MOVEMENT OF SAID GEAR RACK MEMBER, EACH OF SAID MEMBERS INCLUDING AN ARM AND AN ADJUSTABLE POINTED MEMBER SUPPORTED ON EACH OF SAID ARMS, SAID POINTED MEMBERS EACH BEING MUTUALLY PARALLEL AND PERPENDICULAR TO THE DIRECTION OF MOVEMENT OF SAID RACK MEMBER, AN ADJUSTMENT WHEEL HAVING AN OUTSIDE DIAMETER GREATER THAN THE DIAMETER OF SAID PINION AND FIXEDLY MOUNTED UPON A COMMON SHAFT WITH SAID PINION FOR ADJUSTMENT OF SAID PINION, A CONSTANT FRICTION LOCKING DEVICE COMPRISING A DISHED SPRING WASHER POSITIONED UPON SAID SHAFT BETWEEN SAID BODY MEMBER AND SAID WHEEL, SAID SPRING HAVING AN EFFECTIVE RADIUS OF CONTACT AT LEAST IN THE ORDER OF THE RADIUS OF SAID PINION, SAID SPRING PROVIDING A FRICTION FORCE TO RESTRAIN ROTATION OF SAID WHEEL AND SAID PINION TO THEREBY PREVENT INADVERTENT MOVEMENT OF SAID RACK IN RESPONSE TO FORCES UPON SAID RACK ALONE, A GRADUATED DIAL DISK HAVING A DIAMETER SUBSTNATIALLY EQUAL TO THE DIAMETER OF SAID WHEEL AND ADJUSTABLY POSITIONABLE AND ARRANGED TO BE LOCKED UPON THE FACE OF SAID WHEEL TO PROVIDE AN ACCURATE DIRECT READING INDICATION OF THE SEPARATION BETWEEN SAID POINTED MEMBERS AS DETERMINED BY THE POSITION OF SAID PINION AND SAID RACK, THE MAXIMUM EFFECTIVE ADJUSTMENT MOVEMENT OF SAID GEAR RACK BEING APPROXIMATELY EQUAL TO THE DIAMETER OF SAID ADJUSTMENT WHEEL.