IMPROVEMENTS IN ARTISTS' STRETCHERS
Year: 1885

page_text: I, JOSEPH LOXTON RAWBONE of 30 King Street East in the City of Toronto
in the Dominion of Canada Manufacturer, do hereby declare the nature of my
invention for IMPROVEMENTS IN ARTISTS' STRETCHERS, and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention relates to an improved method of constructing artists stretchers or
frames whereon the canvas is stretched for the purpose of painting. And it consists
essentially in the use of a plain mitre-joint, in place of a slip-tenon, and it.
minimises the cost of labor thereby.
My invention also consists in the joining of the mitred members of such frame or.
stretcher, by means of a metal plate, having in it converging slots, and being
secured to the members of said frame with set screws or nails. The advantage of
my device will be hereafter shewn, but I premise that I effect these objects by.
means of the mechanism illustrated in the drawings, in which:-
Figs 1 and 2 shew the method at present in vogue, in the manufacture of artists.
stretchers.
Figs 3 and 4 illustrate the operation of my improvement.
Figs 5 and 6 are a section and plan respectively of the clamping-plate used
by me.
Figs 7 and 8 shew an alternative method of forming the clamping-plate.
From a long experience in such matters, I have found that a stretcher is
required, which shall be easily adjustable, cheap, and secure at all times, the present
method being, in my opinion utterly unsatisfactory, on account of the expense
and trouble involved in cutting tenons on each of the four sides which form the
said frame.
It is obvious that if the artist is a long distance from home, this present method
will be found very inconvenient, as stretchers or frames of varying sizes will be at
all times in request. But a person of any ordinary intelligence is able to cut a
mitre from a board of suitable width, such board being always readily procurable
from the nearest saw-mill, planing-mill or shop. The artist himself night carry a
supply of such boards without inconvenience.
Referring to the drawings:
A A represents too sides of the frame, or stretcher, such sides having heretofore
been joined by means of tenons, and expanded by wedges, or plugs a, a, as shown
in Figs 1 and 2.
It will be seen on reference to Figs 3 and 4 that the sides of the frame are cut,
at each end, to an ordinary mitre, or angle of 45 degrees. Over this mitre I lay a
plate B, made of wrought iron or other material having tensile strength. I then

page_text: attach the plate B to the sides A A of the frame A, by means of set screws, as
shewn, or by nails.
It therefore follows, that on the plate B being thrust forward, in the direction
shewn by arrows, by any kind of pressure, or by a blow on the larger, or convex
end of said plate, the mitre joint will be opened, the edges of the mitre however
still remaining parallel.
This plate B being placed on the back of the frame or stretcher, and the canvas
being tacked on the front of such frame, it follows that on the opening of the
mitres, the whole frame will be expanded, and the area occupied by the canvas
will be increased, the canvas being caused to stretch quite evenly on each of the
four sides.
The economy of this method of constructing the stretcher is not its only
advantage. It has always been noticed that the canvas being strained over a frame
joined by means of tenons (see Figs 1 and 2) will show a distinct line or ridge,
caused by the inner edge of such frame-To obviate this, it has been the practice
It
to bevel off the inner edge, so as to remove it from contact with the canvas.
will be found that by using my improved clamp, the force created by blows or
pressure on the said clamp, will have the effect of opening the mitres at the back
of the frame, while the front of the mitres will remain closed, thus causing the
sides of the frame to cant outwards. towards the rear, see Fig. 4 so that the only
point of contact of the canvas with the frame, will be at the outside edge of the
front of the frame-the canvas being in these drawings denoted by the letter x.
The material of which the plates B are made, allows of their bending sufficiently
for this purpose.
"
The shape of the plate which I prefer is shown in Fig. 6-and it will be seen
that by driving up these plates at each corner of the frame, an equal expansion is
secured, allowing of no wrinkles whatever in the canvas.
A great advantage in my invention is that by.its application the corners of the
stretcher are left square and solid, with no tenons or other projections to interfere
with the tacking on of the canvas.
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
In an artists stretcher, the combination of the diagonal plate B, having con-
verging slots b, and being secured by set-screws b¹, with the sides A, A, of the
stretcher, said sides being cut to a plain mitre, and being joined by the said
diagonal plate B, all arranged and operating as shown and for the purpose
specified.