An Improved Apparatus for the Teaching of Orthographic Projection.
Year: 1891

page_text: Date of Application, 13th Apr., 1891
Complete Specification Left, 13th Jan., 1592-Accepted, 9th Apr., 1832
PROVISIONAL SPECIFICATION.
An Improved Apparatus for the Teaching of Orthographic
Projection.
JAMES COBB, 11 Carberry Place, Burley Lodge Road, Leeds, Yorkshire
Elementary Teacher. I do hereby declare the nature of this invention to be as
follows:-
It consists of two parts; firstly, a means of fixing and readily adjusting an object
in any required position with regard to two pieces of wood or other flat material so
placed as to represent respectively a horizontal and a vertical plane and secondly,
A forked or
means of holding these two planes at right angles with each other.
lotted support for the object terminates at its lower extremity in a ball, which
together with two metal plates, the upper one of which revolves, makes a ball and
socket joint. Secondly a piece of metal hangs from a pivot fixed in a horizontal
bar that fits at its end in a socket in such a way as to let the apparatus revolve
laterally. A tongue of metal is fixed to receive the pressure of this swinging piece
when it is perpendicular, and thus holds the boards or other surfaces at right angles
when required.
1001
COMPLETE SPECIFICATION.
An Improved Apparatus_for the Teaching of Orthographic
Projection.
JAMES COBB 11 Carberry Place Burley Lodge Road Leeds, Yorkshire Teacher,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
Statement :-
:
Two boards are taken each about the size of a single sheet of foolscap or
larger these are hinged together so as to close like a book; through one of
them (N) a circular hole is made 6 inches or more in diameter; a circular metal
plate somewhat larger than this hole is screwed on the under side of this board (Q)
so as to cover the hole entirely; through the centre of this plate a hole (B)
about inch in diameter is bored. Take another metal plate (R) just large
enough to be admitted into the hole in the board (N) and turn round in it without
touching the sides; on the under side of this plate (R) we have in the centre a
tout metal peg (F) threaded to receive a wing nut, and, near its outer edges, about
a third of the diameter of the plate apart, two other metal pegs (C, C) of such a
length that when the central threaded peg (F) is passed through the hole (B) in
the larger plate (Q) these shorter pegs will rest on the larger plate (Q) and hold
the smaller plate at such a distance from the larger plate that the upper surface
of the smaller will be exactly level with the inner surface of the lower board (N);
also, in the smaller plate, equidistant from these pegs, and as near the edge as
possible a hole (D) is bored through this plate about inch in diameter; a
metal ball (E) slightly larger than this hole and tapped to receive a screw is
placed beneath the hole (D) between the two plates, so as to form a third point
of support to the upper plate. It will he now seen that the upper plate will
revolve upon the larger, the threaded bolt (F) protruding beneath the lower
plate and now this revolving plate can be fixed in any part of its revolution
by turning the wing nut beneath and thus causing the upper plate to press in three

page_text: points on the larger lower plate; and further by the same nut the ball which
lies between the plates is also fixed so as to have its tapped hole vertical or
inclined at any required angle to the vertical. Into this tapped hole the metal
model holder (G) may be screwed; or this tapped hole may be used to hold a
wire-model holder which is simply a set screw that binds a wire model between
the screw and the upper plate, or between the screw and any other plate
that may be used either on the flat or supported by the model holder (G).
To fix a model to the model holder, it is necessary to use a set screw to
he received into the model: or it may be that the model is held by a peg
which may be raised or lowered by any convenient method of pressure against
the model-holder, (G). The apparatus is supported by an angle-iron (JJ)
which is screwed on behind the upper board (K). The other end of the angle
iron (1) is provided with a pivot which works in a vertical socket (L). This
socket is screwed to one of the supports of a teacher's desk, blackboard teacher's
desk, blackboard, or other convenient place. The angle-iron (f) is provided with
a slot crossing which is a horizontal pivot and from the pivot a metal rod (M)
hangs loosely. This rod may be lengthened at will by means of a set screw in its
lower extremity. To the lower board (N) a piece of metal (0) is fixed in such a
position that when the lower board is raised to a horizontal position, this piece of
metal (M) will take up a position exactly beneath the rod that hangs loosely and
will thus hold the lower board (N) horizontal. When the hanging rod is swung
away from the boards, the lower board will fall until it assumes a vertical position
and the piece of metal that is screwed beneath it will lie flat against the back of
both boards.
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 adaptation of an adjustable model holder as above described.
(2.) The arrangement of plates by which the ball is bound in a circular series of
positions by the wing-nut.
(3.) The adaptation of the set screw to the revolving plate for the fixing of
models.
(4.) The application of the swinging rod and fixed bar for holding the lower
board horizontal and for affording facility for swinging it readily into a vertical
position for the purpose of teaching projection.
Dated this 10th day of January 1892.
JAMES COBB.