Didactic apparatus
AssigneePhilograph Publications Limited
InventorCharles Arthur Tacey
Life of this patent
Estimating the term…
Abstract
The invention provides didactic apparatus for use by young children in ascertaining the volume of solid structures built from unit cubes or blocks, and broadly comprises a square base plate and two rectangular walls connected at right angles and mounted on said base plate so as to be in planes parallel with but spaced from two adjacent sides of said base plate. Said base plate and walls are each marked with grid lines each square of which is of unit dimensions and the grid lines of the base plate externally of said walls are consecutively numbered from the juncture of the walls. The walls, at least, are transparent and horizontal grid lines thereon are numbered consecutively from the bottom.
Claims1
Didactic apparatus for the purpose specified, and for use with lcm. unit cubes, comprising:
- i. a rectangular base plate having an upper face marked with a grid defining lcm. squares, said grid having its boundaries spaced by a first edge portion from a first edge of the base plate, and by a second edge portion from a second adjoining edge of the base plate, said base including slots,
- ii. a first transparent rectangular wall mounted on said base normal to the plane of said upper face and positioned along the boundary of the grid spaced from the first edge of the base plate, said first wall including a tongue for engagement in a respective slot of the base to locate and connect the wall to the base, said tongue including a shoulder for abutment against the base to retain the tongue in engagement in said slot,
- iii. a second transparent rectangular wall mounted on said base plate normal to the plane of said upper face and positioned along the boundary of the grid spaced from the second edge of the base plate, said second wall being joined at a right angle to said first wall, said second wall including a tongue for engagement in a respective slot of the base to locate and connect said wall to the base, said tongue including a shoulder for abutment against the base to retain the tongue in engagement in said slot, one of said first and second walls includng a T-piece tenon formation remote from the base and the other of said first and second walls including a corresponding recess formation remote from the base for interengegement to connect said first and second walls together, said first and second walls being marked with grid lines defining 1cm. squares commencing from the line of juncture of the walls with the base plate, and the line of junctureof the walls with each other, the grid lines of the base plate being numbered consecutively on said edge portions starting from the juncture of said walls, and the horizontal grid lines marked on said walls being numbered consecutively starting from the juncture of each wall with the base.
Dependencies are inferred from the claim text.