Geometric and other Drawing.
Year: 1885

page_text: Geometric and other Drawing.
I, GEORGE COSSAR PRINGLE of 7 Downfield Place, Dalry Road, Edinburgh in the
County of Midlothian, Teacher, do hereby declare the nature of this invention,
a communication to me from abroad by James Milne Pringle, Balmoral House,
Bathurst, in the Colony of New South Wales, Teacher, to be as follows:-
This invention relates to improvements in drawing boards and it has principally
for its object to facilitate the teaching or explanation of these principles of solid or
descriptive geometry which enter into the constructive arts. The board constituting
the invention consists of four main members or parts so hinged together as to be
capable of forming one or several planes the whole being hung or supported on an
upright frame or stand so that it may be easily raised and lowered it being guided
and maintained in proper position whilst being so raised and lowered by tongues
and grooves in one section of the board and in the frame respectively.
One section of the board constitutes the vertical plane, or plane of elevation,
whilst the section immediately beneath constitutes the horizontal plane, or plane of
plan, this latter being capable of being raised and lowered to and maintained at
any angle relatively with the plane of elevation by means of a notched quadrant
passing through a bar secured to the latter plane. Two other parts of the board
hinged to the plane of elevation constitute the planes of end elevation or section
and each of these latter planes has a portion hinged to its lower end the said
portion being triangular in shape and having another portion hinged to the
hypothenuse. When the plane of plan is at right angles to the plane of elevation
the angular portions above referred to can be folded up and fastened behind the
planes of end elevation or section so as to enable the said planes to make any angle
less than a right angle with the plane of elevation.
In conjunction with one of the planes of end elevation or section a graduated
quadrant is provided to determine the angles this plane makes with that of
elevation

page_text: For holding in position models the projections of which are to be demonstrated,
a rest having both vertical and horizontal quadrants in conjunction with it is
employed. At the angle of the lower quadrant the rest is secured to the plane of
plan by a square or rectangular pin. At the said angle an arm is pivotted so as to
be capable of movement through a horizontal are and to this arm another arm is
also jointed so as to move through a vertical arc. The object to be projected rests
upon this arm and to the free end of the horizontal arm a quadrant is hinged the
said quadrant having notches for the support at any desired angle in a vertical
plane of the arm carrying the object whilst the adjustment in a horizontal plané
is effected by moving the free end of the horizontal arm over the horizontal
quadrant.
The apparatus hereinbefore described, by means of the various combinations
and arrangements of planes and quadrants of which it is capable and consequently
of its capacity for practically illustrating different positions of the object to be
projected, greatly facilitates and simplifies the comprehension of the principles of
geometrical projection in teaching mechanical or constructive drawing and generally
it is of service in practically illustrating the determination of oblique lines and
planes in geometrical and perspective drawing, plans, elevations, and sections in
architectural drawing, and different views of the same object in model drawing.

page_text: Geometric and other Drawing.
I, GEORGE COSSAR PRINGLE of 7 Downfield Place Edinburgh do hereby declare
the nature of the invention for AN IMPROVED GEOMETRICAL DRAWING BOARD
a communication from James Milne Pringle, New South Wales, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:—
This Invention relates to an Improved Geometrical Drawing Board for use in
teaching and facilitating the demonstration of the principles of solid and descriptive
Geometry used in the constructive arts; practically illustrating the determination
of oblique lines and planes in Geometrical and perspective drawing; the use of
plans, elevations and sections in Architectural Drawing; illustrating different
views of the same object in model drawing; and for the ordinary uses of a
blackboard.
On the annexed sheet of Drawings Fig. 1 is a front elevation of the board
with one of the parts B raised horizontally. Fig. 2 is the elevation of a vertical
section through the centre of the board.
The Board as illustrated consists of several parts or planes hinged together so as
to be capable of forming one plane. The principal board A which may be termed
the Plane of Elevation is or may be attached or suspended to an upright frame
(not shown) by means of cords, weights and pulleys or otherwise in the most
convenient manner. To the bottom of the board A is hinged the board B which
may be termed the Plane of Plan. To the sides of the principal board A are
hinged the boards C. D. which said boards may be termed the Planes of Section or
End Elevation. To the bottom of last said boards O D are hinged by double
hinges as shown at Fig. 3 the triangular boards E, F, so as to be capable of being
turned back wards or forwards. To the hypotenuse side of the said triangular
boards E. F. are hinged respectively the boards G, H. To the back of the board B
is fixed one end of a semicircular supporting metal bar i which slides through a
hole in the lower end of the metal bar K which is fixed rigidly to the back of the
board A. The semicircular metal bar i may be graduated to degrees so that the
board B may be set to certain angles thereby with the board A, and fixed thereat
by the pinching pin l.
Into one of the corners of the boards F, H, and B, are set in three parts
corresponding to the size of angle of boards, two quadrants m graduated so that
certain relative angles which may be made by the boards B and D to the board A
may be determined.
The various planes of the board are constructed so as to make any angle with
one another, the angles being determined by the graduated quadranta The lower
planes E. F. can be turned up behind and the upper planes E. D. can then move
over plane of plan B and make any angle less than a right angle with Plane of
Elevation A.
The side Planes C. D can be used for end elevations or sections,

page_text: For the purpose of holding wire models of solids in various positions on the
board B, an adjustable bolder is provided consisting of a horizontal and vertical
quadrant and two arms. The horizontal quadrant n has a small square pin o
projecting downwards therefrom at angle, which being inserted into a corresponding
square socket in the board B. keeps one side of the said quadrant parallel to the
hinged side of said board. One end of the lower arm p is attached by a pivot to
the horizontal quadrant n at its angle so that the free end of the said arm may
slide round the face of the quadrant n. The upper arm is hinged to lower arm p
at the pivotted end thereof and has a slot in the free end through which passes the
vertical quadrants having notches every ten degrees to catch arm and hold it at
the required angle. The lower end of vertical quadrant is attached to the free end
of the lower arm p, which rotating on the pivot moves on the face of the horizontal
quadrant. Upon the upper arm is placed the wire model of a solid t which is
kept in position by means of a rest at hinged end and a catch at other end
thereof. The model can thus make any angle with the vertical and horizontal
planes.
The left hand edge of the boards C and B are or may be provided with brass or
other metal edges and measurement scales, on which to work T squares.
The board may be conveniently used for Geometrical Drawing by raising the
board B or plane of plan until it makes a right angle with the vertical plane A,
and fixing it thereat by the pinching pin l. The model or object to be drawn
having been placed on the plane of plan in the required position, the projections
can be determined 1st from observation or by measurement; or 2nd the drawing
can be made before the model is placed on the board, and the model being then
placed over the drawing the projections must coincide with the model.
The model being removed and the plane of plan turned into the vertical plane
the drawing and its projections will appear on the board as on an ordinary drawing
on paper.
By removing the models and quadrant holder, and putting the several boards
into one plane and fixing them therein by pins on back (not shown) or otherwise
as most convenient, the board may be used as an ordinary blackboard, or it may be
folded up and made to lock.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed I declare that what
I claim is
1 The arrangement and combination of several boards hinged together sub-
stantially as and for the purposes described and shown.
2nd The combination of the vertical and horizontal quadrants 8 and n, as and for
the purposes set forth.
3rd Fitting the boards with graduated quadrants whereby their relative angles
may be determined, as set forth.
Dated this second day of July 1886.