Improvements in Pneumatic Boot Trees.
Year: 1898

page_text: Date of Application, 16th Mar., 1898-Accepted, 18th June, 1898
Improvements in Pneumatic Boot Trees.
I, FRANK GRAFTON-WIGNALL, of North Down, Heathfield, Sussex, Gentleman,
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:―
My invention relates to improvements in pneumatic boot trees adapted to be
inflated with air after insertion in the boot and by my invention I am enabled
to exert pressure on every portion of the boot from within.
In pneumatic boot trees as heretofore constructed there has always been a
tendency for the trees when inflated to creep out of the boot however tightly
laced and to overcome this inconvenience attempts have been made to render the
upper portion of the boot tree that is the portion which corresponds to the ankle
and lower portion of the leg inelastic, thereby not only increasing the weight of
the tree as a whole but making it impossible to apply any pressure to that portion
of the boot which lies above the ankle.
Now by my invention I am able to make a pneumatic boot tree consisting of a
single air chamber which although formed (with the exception of a small metal plate
at the top) wholly of rubber and canvas is nevertheless capable of maintaining
its shape when inflated so perfectly that there is no tendency to creep out of the
boot.
To this end I employ two different thicknesses of rubber and stiffenings of
canvas so disposed and arranged that while the tree cannot get out of shape it can
nevertheless expand so as to fill the whole boot when inflated and thus is able
to remove any wrinkles or creases in the boot.
In order that my invention may be clearly understood I proceed to explain
the same by reference to the annexed drawing.
a, b, c, d, e is the sole consisting in a thick closely woven canvas sock, covered
externally that is below the sole with thick sheet rubber. The various edges
of the upper are lapped over underneath the canvas sock and solutioned down
and the external rubber sole is then solutioned over such edges so as to securely
retain them in position.
d, e, f represents the toe portion of my improved last and is formed of one
piece of thin sheet rubber without any canvas backing so that of all portions it
may be the one most easily expanded by inflation. Above and behind the toe
portion of the upper I insert a strip of thick rubber without canvas back-
ing c, d, f, g. This strip is however formed in two picces with an overlapping
join along the line f, g whereas the toe portion is made in one piece with no join
along the line f, e, that is to say the portion of the strip which is seen in the
drawing and another similar portion on the other side of the last form a con-
tinuous strip with an overlapping join at f, g.
a, c, g, h, is a piece of thick rubber joined to a similar piece on to the other
side of the last along g, h and a, j, by a lap joint joined to the sole along a, e and
lapping over a thin metal plate p, of elliptical shape along the line h, k, j
and joined to the aforesaid strip c, d, f, g along the line c, g by a lap joint. With

page_text: the exception of the portion a, b, m at the extreme heel the whole of this portion
of the upper is lined and stiffened with canvas m, b, c, g, h, k, j, solutioned on
to the rubber; but the portion a, b, m is left unlined. A strip of canvas k, b,
is employed to act as an additional support to the metal plate and is affixed thereto
and carried round beneath the canvas sock or sole and up to the plate on the other
side being affixed throughout its length to the canvas lining and the upper ends
of this strip are connected by a web of canvas stretching from one to the other
within the last and joining them for the first three or four inches from their upper
ends. The various portions of the last which are attached to the plate p, are
lapped over and solutioned to the plate a piece of canvas-lined thick rubber being
cemented down on to them, and a strip of rubber h, k, j is then solutioned round
the edge so as to slightly over-lap the edge of the plate.
It will be found that if the construction is followed the stiffening produced
by the canvas lining and strips and by the lap joints h, g, f, j, m, a, and g, c will
enable the last to be inflated without losing its shape or becoming deformed.
Any suitable non-return valve r may be inserted in the plate p, to enable the
tree to be inflated by the mouth or a pump as desired.
Having now particularly described and ascertained the nature of my new
invention and in what manner the same is to be performed I declare that what
I claim is:
-
The pneumatic boot tree substantially as and for the purposes described.