Drafting machine

Claim 1

AN IMPROVED DRAFTING MACHINE, COMPRISING: A TSQUARE FOR A RECTANGULAR DRAWING BOARD HAVING A TOP DRAWING SURFACE AND SUBSTANTIALLY PARALLEL LATERALLY SPACED GROOVED SIDE EDGES, SAID T-SQUARE INCLUDING A SIDE-EDGEENGAGING HEAD MEMBER PROVIDED WITH AN INWARDLY DIRECTED PROJECTION ADAPTED TO SLIDABLY ENGAGE ONE GROOVED SIDE EDGE OF THE DRAWING BOARD AND INCLUDING LONGITUDINAL BOARD-SURFACE-ENGAGEABLE TRANSVERSE MEMBER ADAPTED TO LIE UPON THE TOP SURFACE OF THE DRAWING BOARD PERPENDICULAR TO SAID SIDE EDGES; AN ATTACHMENT MEMBER ADJUSTABLY CARRIED BY SAID BOARD-SURFACE-ENGAGEABLE TRANSVERSE MEMBER OF THE T-SQUARE LATERALLY SPACED FROM THE TSQUARE HEAD MEMBER AND HAVING A SIDE-EDGE-ENGAGING MEMBER PROVIDED WITH AN INWARDLY DIRECTED PROJECTING PORTION ADAPTED TO SLIDABLY ENGAGE THE OTHER GROOVED SIDE EDGE OF THE DRAWING BOARD IN OPPOSITION TO SAID HEAD MEMBER WHEREBY TO FIRMLY RETAIN THE T-SQUARE ON THE TOP SURFACE OF THE DRAWING BOARD IN A MANNER CONTROLLABLY ALLOWING IT TO BE MOVED IN A DIRECTION PARALLEL TO THE SIDE EDGES OF THE DRAWING BOARD, SAID INWARDLY DIRECTED PROJECTING PORTION OF SAID ATTACHMENT MEMBER BEING RESILIENTLY INWARDLY BIASED WHEREBY TO ALLOW IT TO BE FORCIBLY RESILIENTLY ENGAGED AND DISENGAGED WITH RESPECT TO AN ADJACENT GROOVED SIDE EDGE OF THE DRAWING BOARD TO FACILITATE REMOVAL AND RE-ENGAGEMENT OF THE ENTIRE T-SQUARE AND ATTACHMENT MEMBER WITH RESPECT TO THE DRAWING BOARD, SAID ATACHMENT MEMBER INCLUDING MANUALLY ADJUSTABLE AND CONTROLLABLY LOCKABLE ENGAGING MEANS FOR REMOVABLY AND INTERCHANGEABLY ENGAGING OPPOSITE EDGES OF BOARDSURFACE-ENGAGEABLE TRANSVERSE MEMBERS OF DIFFERENT-SIZED T-SQUARES; AND PROTRACTOR ATTACHMENT MEANS FOR TRANSVERSELY SLIDABLE AND CONTROLLABLY LOCKABLE AND REMOVABLE ATTACHMENT TO THE BOARD-SURFACE-ENGAGEABLE TRANSVERSE MEMBER OF THE T-SQUARE AND INCLUDING A PROTRACTOR BASE MEMBER HAVING A FLAT BOTTOM SURFACE ENGAGEABLE WITH THE TOP SURFACE OF THE DRAWING BOARD, SAID PROTRACTOR BASE MEMBER BEING PROVIDED WITH A STRAIGHT EDGE MEMBER HAVING A FLAT BOTTOM SURFACE ENGAGEABLE WITH SAID TOP SURFACE OF SAID DRAWING BOARD AND BEING FURTHER PROVIDED WITH ROTATIVE MOUNTING MEANS EFFECTIVELY ROTATIVELY MOUNTING A REAR END OF SAID STRAIGHT EDGE MEMBER WITHIN SAID PROTRACTOR BASE MEMBER, WITH ONE OF SAID MEMBERS BEING PROVIDED WITH PROTRACTOR ANGULAR SCALE MEANS ARCUATELY ARRANGED AND WITH THE OTHER OF SAID MEMBERS BEING PROVIDED WITH AN INDEX PART ARCUATELY MOVABLY COOPERABLE WITH THE PROTRACTOR ANGULAR SCALE MEANS FOR INDICATING THE ANGULAR ORIENTATION OF THE BOARD-SURFACE-ENGAGEABLE STRAIGHT EDGE MEANS WITH RESPECT TO THE BOARD-SURFACEENGAGEABLE TRANSVERSE MEMBER OF THE T-SQUARE; SAID ROTATIVE MOUNTING MEANS FOR ROTATABLY MOUNTING SAID BOARDSURFACE-ENGAGEABLE STRAIGHT EDGE MEMBER COMPRISING A MULTIPLE TEMPLATE-CARRYING MEMBER PROVIDED WITH MULTIPLE BOARD-SURFACE-ENGAGEABLE TEMPLATES AND HAVING A FLAT BOTTOM SURFACE ENGAGEABLE WITH SAID TOP SURFACE OF SAID DRAWING BOARD AND MEANS CARRIED BY SAID BOARD-SURFACEENGAGEABLE PROTRACTOR BASE MEMBER FOR ROTATABLY MOUNTING SAID MULTIPLE TEMPLATE-CARRYING MEMBER FOR ROTATION OF ITS BOTTOM SURFACE IN THE SAME PLANE AS THE BOTTOM SURFACES OF SAID PROTRACTOR BASE MEMBER AND SAID STRAIGHT EDGE MEMBER IMMEDIATELY ABOVE THE TOP SURFACE OF SAID DRAWING BOARD, SAID MULTIPLE TEMPLATE-CARRYING MEMBER BEING PROVIDED WITH PIVOT PIN MEANS ROTATIVELY PROVIDED WITH AND CARRYING A COUPLING MEMBER CONNECTED TO SAID BOARD-SURFACE-ENGAGEABLE STRAIGHT EDGE MEMBER FOR ROTATABLY MOUNTING SAID STRAIGHT EDGE MEMBER WITH RESPECT TO SAID BOARD-SURFACE-ENGAGEABLE MULTIPLE TEMPLATE-CARRYING MEMBER AND WITH RESPECT TO SAID BOARD-SURFACE-ENGAGEABLE PROTRACTOR BASE MEMBER.