Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Inventor
Pierre Roch
Etienne Challet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IndividualfiledCriticalIndividual
Application grantedgrantedCritical
Publication of GB191004505ApublicationCriticalpatent/GB191004505A/en
B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
B43L—ARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
B43L7/00—Straightedges
B43L7/027—Plural non-adjustable straightedges fixed at right angles
B43L7/0275—Triangles
Abstract
4505. Roch, P., and Challet, E. Feb. 23. Protractors. - An instrument for use as a square and for setting-off angles comprises a set-square in the form of a trapeze having an inclined stay e and a side a-b forming given angles of 30 degrees and 60 degrees, for example, to the base a-d, and a rule A tangential to these angles arranged to slide on the square and graduated so as to indicate the angle added to the given angles when the square is turned on a base M-N, and the slide A brought to bear on this same base.