Improvements relating to T-Squares.
Year: 1893

page_text: Date of Application, 28th Aug., 1893
Complete Specification Left, 28th May, 1894-Accepted, 28th July, 1894
PROVISIONAL SPECIFICATION.
Improvements relating to T-Squares.
I JAMES PORTER MAGINNIS, of 9 Carteret Street, Queen Anne's Gate,
Westminster, S.W. London, Civil Engineer, do hereby declare the nature of this
invention to be as follows :-
The invention consists of an attachment which may be readily applied to or
removed from any existing T square having a fixed head or stock, such attachment
when used in combination with a T square giving to the latter the advantages of
a moveable head or stock, or the attachment may readily be removed, when the
T square resumes its original appearance and form, and may be used in the same
manner as though the attachment had not been applied to it.
My invention consists essentially of a flat bar of wood or other suitable material
having a working edge truly planed or otherwise made perfectly straight. This
bar is of such a form that it may be placed between the head of any ordinary
Tsquare and the working edge of a drawing board.
I also provide means for attaching this bar to the head of a T square in such a
manner that the bar and the head may be either parallel to each other, or at any
One means of
required angle within the limits of my means of adjustment.
attachment and adjustment consists in the employment of slotted links one end of
which may be attached to the head of the T square and the other to the bar.
These links are provided with suitable bolts or screws and nuts for the purpose of
locking the links at any point. Or I may employ other means of arriving at the
same result. It will now be evident that if this bar be fixed by the means
described, in a position with its inner or working edge parallel to the inner or
working edge of the head of the T square, and placed in close contact with the
working edge of a drawing board, all lines ruled against the working edge of the
blade will be at right angles to the working edge of the head of the T square;
or should the bar be fixed in such a way that the working edges of the head of the
Tsquare and of the bar are at an angle to each other, any lines now ruled against
the blade of the T square (whilst the working edge of the bar is in close contact
with the working edge of the drawing board) will be at an angle to the lines
previously ruled, such angle being equal to the angle above referred to.
Should it be desired, the bar and the slotted links may be detached, when
the square will resume its ordinary appearance, and may be used in the
ordinary way.
Dated this Fifteenth day of September 1893.
Improvements relating to T-Squares.
I JAMES PORTER MAGINNIS, Civil Engineer, of 9 Carteret Street, Queen
Anne's Gate, Westminster, S.W. London 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 :-
This bar is
In these improvements I employ a bar A provided with two slotted metal
struts B. B', secured to it by means of screws or rivets C. C¹.
placed against the working edge of the head or stock D, and under the blade E
Price 8d1

page_text: of an ordinary T-square, so that the struts lie on the surface of the head. By means
of milled screws F. F1 passing through the slots of the struts into plug-nuts G. G'
fixed in the head of the T-square, the bar A may be securely locked at any
desired angle (within specific limits) to the blade of the T-square, and if the
"T-square be put in position on a drawing board with the edge of the bar doing
duty for the working edge of the head, the blade will have an inclination corre-
sponding to the angle at which the bar is fixed.
The plug-nuts H. H' screwed into the bar form resting places for the milled
screws F. F' when the bar is out of use and removed from the T square or the
drawing board.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The employment of a suitable bar, having suitable struts attached thereto, so
that it may be readily attached to auy ordinary T-square in the manner described,
or removed from it, as desired.
2. The application of such a bar to any ordinary T-square to give any desired
inclination to such T-square blade.
3. The combination of a T square and adjustable bar, used in conjunction with
a drawing board.
Dated this 28th day of May 1894.
JAMES P. MAGINNIS.