Improvements in or relating to instructional or educational apparatus

摘要

673,326. Appliances for teaching drawing and geometry. MURRAY, G. L. April 24, 1950 [April 26, 1949], No. 11021/49. Classes 11 and 146 (ii). Instructional or educational apparatus for demonstrating three dimensional geometry and methods of projection comprises a rectangular member 2 to adjacent edges of which further members 1, 3 are hinged, each member representing a different plane and bearing a view of an object 4 appropriate to the positions of the planes in their three dimensional association, such members being capable of being opened out into a single plane to represent a sheet of paper showing the correct positions of the respective views. In the example the object or model 4 comprises a rectangular parallelopiped having circular-, triangular-, and square-section projections 4a, 4b and 4c respectively. The base panel 1 bears a plan 5, the back panel 2 a front elevation 6 and the right-hand end panel 3 an end view 7 (looking on the triangular projection 4b) of the object. When opened out into the plane of the base 1, the three panels 1, 2, 3 represent first angle or English projection. A further three panels 11, 12, 13 bear views corresponding to those on the panels 1, 2, 3 respectively and are hinged together to open out into the plane of the top panel 11. They represent third angle or American projection. Four rods 10 are mounted in the base 1 and the top panel is removably mounted on reduced upper extensions 10a thereof. Preferably the panels 1, 2, 3 are opaque and the panels 11, 12, 13 transparent, but all six may be the same. The views may be permanently inscribed or printed on the panels or they may comprise prints fixed to but readily removable from the panels for exchange with another set appropriate to a different object or model 4. The model 4 is carried on a stem 21 received in an aperture in the base.