Improvements in Rulers or Squares for Geometrical and other Drawing on Black Boards.
Year: 1898

page_text: Date of Application, 8th Feb.,
1898
Complete Specification Left, 3rd Aug., 1898-Accepted, 1st Oct., 1898
PROVISIONAL SPECIFICATION:
Improvements in Rulers or Squares for Geometrical and other
Drawing on Black Boards.
JOSEPH ANDREW LABAT-GUILMANT, The Gables, Newbold Road, Chesterfield,
Assistant Master, Grammar School, do hereby declare the nature of this inven-
tion to be as follows:--
A ruler acting upon the principle of the ordinary T square for the drawing
of horizontal lines but which by means of a spring adheres to the black board
and being fitted with a movable hinged arm enables the operator to draw parallel
lines at any angle without the aid of set squares or other contrivances.
The ruler is composed of two flat pieces of wood marked in drawing A A
and B B, A A is fixed in the stock C and plays freely through the block D,
while B B plays freely through C and can be fixed to block D by means of a
screw.
On manual pressure being applied to the left extremity of B B it is forced
through the stock C & carries with it the block D and at the same time pushes
The ruler may then be moved
forward a false stock E E E with smooth surface.
up or down the black-board working upon the false stock.
Upon the pressure being removed B is brought back by means of spring G
carrying block D with it, the false stock E falls back and the ruler adheres to
the black-board by means of the rubber surfaces on stock C and block D. The
movable arm consists of third flat ruler K, K, attached to a pivot on the sliding
block H, This block is held between the two first mentioned flat rulers A and B
and is enabled to slide freely from end to end of them by its attachment to a
narrow strip of wood fitting into grooves behind the 'said rulers A & B.
The pivot end of the movable arm can thus be placed on any point of flat
ruler A. and can be placed at any angle thereto.
In the said movable arm is a slot for the reception of a bolt and thumb screw
nut which is fastened to one end of a shorter movable stay L. At the other
end of the stay L is a small hole made to fit on a peg H₁ at either end of the
strip to which the movable block H is attached.
Marks on K show at what angle. it is set.
Improvements in Rulers or Squares for Geometrical and other
Drawing on Black Boards.
JOSEPH ANDREW LABAT-GUILMANT, The Gables, Newbold Road, Chesterfield,
Assistant Master Chesterfield Grammar School, do hereby declare the nature of

page_text: this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
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い
A flat piece of wood A A is fixed in the wooden stock C, C, C, and can pass
freely through block D. A second flat piece B1 B2 passes freely through C, C, C,
but is fixed in D at the distance required to suit the size of black board by means
of screw in D.
A false stock E E to which B1 B2, is fixed has projections which can play
through two grooves cut in C, C, C. These projections are faced with flat pieces
of metal P, P, larger than the grooves which prevent E E from coming out
of C, C, C.
→
O, O, is a handle for the fingers placed behind the false stock E E and
fastened to CCC. G is a wire spring one end fastened to B1 B2 the other end
to G.
Upon pressure being applied at extremity B1 B1 B2 is forced through
stock C, C, C, carrying with it D, at the same time the false stock E E is brought
forward exposing its metal surfaces P, P. The ruler can now be moved up or
down the black board working upon P, P. When the pressure is relaxed E E
falls back, C, C, C, is drawn in towards D) by spring G and C, C, C, and D adhere
firmly to the sides of the black board by means of the india rubber sur-
faces F F F F and F F with which C, C, C, and D are provided.
A third flat piece of wood K K is attached to a pivot on the block H which
being fastened to a flat piece of wood working in grooves behind A A and B1 B2
can slide from end to end of A A and B-1 B2.
K K working on its pivot can be placed at any angle with A A and be kept at
that angle by means of a stay L having at one end a thumbscrew N working
through a groove in K K and the other end being placed on a pin H2 or H1.
The angles formed are marked on K K and are shown by a piece of metal M
traversed by the thumb screw N and which glides up and down groove in K K
with the screw N.
The three pieces A. A, B1, B2 KK are ruled to show inches &c.
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:-
4
3
1. A ruler which can be fitted to any ordinary black board and adhere to it
and which upon pressure being applied can be moved upwards or downwards 3
enabling the operator to draw horizontal lines, and which when the pressure
is removed remains adhering to the black board.
2. A system by which lines at any required angle to the horizontal may be
drawn upon a black board without the use of ordinary T squares and set squares.
Dated this 2nd day of August 1898.
JOSEPH A. L. GUILMANT.