Microscope having bridge type support arm for body tube and focusing mechanism

Claim 1

A MIRCROSCOPE COMPRISING IN COMBINATION A BASE, A BODY TUBE AND A BODY TUBE CARRYING ARM IN THE FORM OF A BRIDGE SPANNING THE BASE, SAID ARM BEING SUPPORTED FROM BOTH SIDES OF SAID BASE IN NO MORE THAN THREE LOCALIZED BEARING AREAS, SAID BEARING AREAS BEING LOCALIZED INTO A POINT, A LINE, AND A SMALL AREA PLANE, SAID BRIDGELIKE ARM RESTING AT ONE END ON A MOVABLE DRIVING PIECE CONNECTED TO THE BASE BY A FINE ADJUSTMENT FOCUSING MECHANISM FOR ELEVATING AND LOWERING SAID END OF THE ARM, AND THE OTHER END OF SAID ARM RESTING UPON THE SPACED BALL BEARINGS, ONE SEATED IN THE BASE IN A CONICAL OPENING AND THE OTHER SEATED IN A STRAIGHT LINE CHANNEL HAVING A V-SHAPED CROSS SECTION, SAID FINE ADJUSTMENT FOCUSING MECHANISM COMPRISING AN ELONGATED TUBULAR CORE AFFIXED AT ONE END TO SAID BASE, THE EXTERIOR OF ONE PORTION OF SAID CORE HAVING THREADS OF A SELECTED PITCH, A SLEEVE SLIDABLE ON ANOTHER PORTION OF THE CORE AND HAVING EXTERNAL THREADS OF A SLIGHTLY DIFFERENT PITCH, AN ELONGATED NUT HAVING SEPARATE INTERNAL SECTIONS WITH THREADS OF DIFFERENT PITCHES MESHING WITH THE THREADS OF SAID CORE AND SLEEVE, AND MEANS MOVED BY SAID SLEEVE IN ENGAGEMENT WITH SAID DRIVING PIECE TO MOVE THE LATTER AND SAID ARM UPON TURNING MOVEMENT OF SAID NUT.