IMPROVEMENTS IN SPRINGS FOR RAILWAY VEHICLES AND FOR OTHER PURPOSES
Year: 1882

page_text: LETTERS PATENT to Alfred Julius Boult of the firm of W. P. Thompson
& Boult, Agents for Foreign Patent Solicitors, of 323 High Holborn, London
in the County of Middlesex and 6 Lord Street Liverpool in the County of
Lancaster, for an invention of "IMPROVEMENTS IN SPRINGS FOR RAILWAY
VEHICLES AND FOR OTHER PURPOSES."-A communication from abroad by
Joseph Drew Thomas and Leonard F. Requa, both of the City and State of
New York, United States of America.
PROVISIONAL SPECIFICATION left by the said Alfred Julius Boult at the
Office of the Commissioners of Patents on the 18th March 1882.
ALFRED JULIUS BOULT of the firm of W. P. Thompson & Boult, Agents for
Foreign Patent Solicitors of 323 High Holborn, London in the County of
Middlesex, and 6 Lord Street Liverpool in the County of Lancaster, 'IMPROVE-
MENTS IN SPRINGS FOR RAILWAY VEHICLES AND FOR OTHER PURPOSES [A com-
munication from abroad by Joseph Drew Thomas and Leonard F. Requa, both of
the City and State of New York United States of America.
"
This invention aims to provide an improved form of air spring for use as buffers
in railway vehicles or for elastically supporting the bodies of carriages or other
vehicles upon their trucks or wheels or for various other purposes where such
springs are applicable and my invention relates to such springs as are formed with
a hollow rubber or elastic body charged with a confined mass of air, compressed or
normal, whereby the weight and cost is reduced while the elasticity of the spring
is increased.
The present improvements aim to greatly increase the weight supporting power
of the spring without reducing its elasticity or increasing its cost whereby much
smaller springs will perform a greater duty and it also aims to increase the range
of. extension or elasticity in the walls of the hollow spring and at the same time
impart great strength thereto.
In one case heretofore a hollow rubber spring has been constructed with a charge
of compressed air, but the hollow rubber vessel was formed without any sustaining

page_text: web or fabric in its elastic walls and the spring was not only held at both ends
but also enclosed around the sides by a metallic case and was bound with metal
hoops whereby the rubber vessel had little or no power of expansion laterally;
which would have been injurious to it but was simply compressed vertically in its
case by a plunger above it.
According to this improvement a hollow rubber spring is so made as to be
adapted to be charged with compressed air and to be held at opposite ends only
and be freely exposed on its sides and capable of free lateral expansion and con-
traction under the varying action of the load whereby a light spring having both
great weight-supporting power and great range of elasticity, is produced, as
hereinafter described The second feature of this invention consists in embedding
within the rubber or elastic walls of the hollow spring a sustaining web of canvas
or other material arranged in sinuous or fluted form which allows the spring to
expand to a great degree before any appreciable strain is exerted upon the web as
hereinafter set forth.
Simply described the spring is a hollow elastic air vessel or cushion the exact
form or size of which is not material, but the spring is preferably made in a true
cylindrical form of square proportion, that is, having an external diameter equal to
its extreme height, a very good size for general railway use being about 8 inches in
both directions that is both in diameter and height and in this size it is preferred
to make the walls of the spring or cushion both on the side and on the ends about
an inch and a half thick throughout, thus leaving a cylindrical cavity within
measuring five inches by five. These walls should of course be made of some strong
and flexible or elastic material such as vulcanized rubber.
This spring is made in the usual manner in which other hollow rubber articles
äre made viz: with a sustaining web or frame of canvas or other suitable fabric,
embedded within its rubber walls, which pervades both the vertical sides and the
heads of the cylinder.
The edges or ends of the canvas in the sides of the cylinder are joined or inter-
laced with the edges or ends of that in the ends at the corners or angles of the
cylinder, thus forming a continuous frame or web within the rubber walls. From
three to seven layers of canvas may be used being cemented closely to each other
by thin films of rubber cement, but more or less may be used.
The canvas in the sides of the cylinder is arranged in sinuous folds or flutes or
in scalloped form, which as will be readily understood allows the rubber cylinder
to expand or distend when under the stress of a sudden force before any tearing
strain will be exerted on the canvas and at the same time the canvas firmly supports
the rubber whether quiescent or under tension. The canvas layers in the heads of
the cylinder are laid flat or level as the heads are designed to be practically non
extensible in a radial direction.
The canvas in the sides of the cylinder is preferably cut on the bias which brings
the woven mesh diagonal to the circumference of the cylinder consequently the
mesh possesses a great mobility or power of circumferential extension and vertical
contraction similar to a lazy tongs, which thus gives the spring great range of
extension without positively straining the strands or threads of the canvas.
In one end of the elastic cylinder is arranged a suitable valve by which the
cavity of the cylinder may be charged with compressed air or gas to any desired
pressure and then closed or sealed to retain the charge. This valve consists of a
seat or socket having a broad flange embedded in the rubber of the head and a
neck or nipple which extend inward and opens into the air cavity. Into the
socket is screwed a hollow valve plug having at its lower end a valve disk which
is adapted to seat on the boss of the socket and cover the mouth of the nipple.
The valve plug has a broad flange at the top which may be seized by a pin wrench
to screw the the plug to or from its seat and it also has a central bore into which is
screwed the end of a pipe through which the compressed air may be conveyed.
The bore up the plug does not extend through to the end but opens laterally there-
from into the cavity of the socket from whence the air will How when the valve

page_text: plug is raised from its seat through the nipple into the cavity of the spring The
compressed air may thus be forced through the pipe and valve into the cavity of
the spring till accumulated to the desired pressure when the air may be shut off
and the plug screwed down firmly to its seat after which the air pipe may be
unscrewed and the spring is then ready for use.
It is preferred to charge the springs when of the dimension before stated with
air or other gas to a pressure of about 30 pounds to the square inch, but much
less than this may be used, although it is not desirable to use much more. The
pressure will have little or no tendency to laterally distend the walls of the spring
when quiescent owing to their thickness and strength and to the fact that the
pressure on the ends tending to longitudinally extend the spring about balances
the lateral pressure on the sides which tends to flatten it, so that hence the spring
will retain substantially a cylindrical shape when not under stress It will thus be
seen that the strong internal pressure to which the spring is constantly subjected
by reason of its charge of compressed air gives it a great resistant or weight
supporting power over what it would possess if charged simply with air at the
atmospheric pressure while at the same time its ratio and range of elasticity is
precisely the same as it would possess if charged with air only at the atmospheric
density; hence springs of much less size and weight of rubber may be made to
perform the same or a much greater duty than heretofore thereby conducing greatly
to cheapness and compactness as well as efficiency, for a hollow rubber spring
charged with air or gas whether atmospheric or compressed, possesses a most
constant and permanent quality of clasticity.
"
When used in supporting the bodies of railway vehicles upon their trucks the
spring may be socketed between two plates having broad flat bearing faces to abut
against the flat ends of the cylindrical spring and with deep flaring rims having
nicely rounded edges which allows the spring to bow outward when under stress
without presenting any sharp or cutting edge to the rubber. One of the socket
plates is of course affixed to the body of the vehicle and the other to the truck or
one to the truck and the other to the axle box as will be readily understood
according to the position in which the spring is used. The spring may of course
be applied and fixed in various ways according as it is employed as a "buffer" or
'spring" which attachments do not form any essential part of this invention and
need no description here. It will be noted however that in this case the hollow
rubber vessel or air spring is held at its opposite ends only and that its sides are
freely exposed. Hence the spring is free to expand or contract laterally under the
varying stress of the load and its full range of elasticity is available, whereas
heretofore the hollow compressed air spring has been enclosed around its sides by
a metal case and furthermore bound with metal rings to prevent or limit lateral
expansion. In the case referred to, lateral expansion would be injurious to the
rubber spring as it was formed without a sustaining web or fabric in its walls.
Hence when forced to expand or contract vertically its range of elasticity is less
and there is added to the spring a great weight of metal, in the compressing
plunger enclosing cylinder and binding rings which render the spring much heavier
than a solid rubber spring and with less range of elasticity, whereas the important
qualities sought to be secured in this spring are greater lightness and greater
elasticity and weight-supporting power which features combine to render this
spring a distinct improvement in this line. Instead of using the form of valve
described for sealing the spring any other suitablle one may be employed and if
preferred, the valve may be covered over and completely concealed by rubber after
the spring is charged. Instead of a metallic valve the aperture through which the
spring is charged may be sealed with a plug of rubber forced into the same and
cemented, if preferred.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Julius Boult in the Great Seal Patent Office on the
18th September 1882.
ALFRED JULIUS BOULT of the firm of W. P. Thompson and Boult Agents for
Foreign Patent Solicitors of 323 High Holborn London in the County of Middlesex
and 6 Lord Street Liverpool in the County of Lancaster "IMPROVEMENTS IN
SPRINGS FOR RAILWAY VEHICLES AND FOR OTHER PURPOSES A communication
from abroad by Joseph Drew Thomas and Leonard. F. Requa both of the City and
state of New York United States of America.
"
This invention aims to provide an improved form of air spring for use as buffers
in railway vehicles or for elastically supporting the bodies of carriages or other
vehicles upon their trucks or wheels or for various other purposes where such
springs are applicable and my invention relates to such springs as are formed with
a hollow rubber or elastic body charged with a confined mass of air, compressed or
normal whereby the weight and cost is reduced while the elasticity of the spring is
increased.
The present improvements aim to greatly increase the weight supporting power
of the spring without reducing its elasticity or increasing its cost, whereby much
smaller springs will perform a greater duty and it also aims to increase the range
of extension or elasticity in the walls of the hollow spring and at the same time
impart great strength thereto.
In one case heretofore a hollow rubber spring has been constructed with a charge
of compressed air, but the hollow rubber vessel was formed without any sustaining
web or fabric in its elastic walls and the spring was not only held at both ends
but also enclosed around the sides by a metallic case and was bound with metal
hoops whereby the rubber vessel had little or no power of expansion, laterally,
which would have been injurious to it but was simply compressed vertically in its
case by a plunger above it.
According to this present improvement a hollow rubber ring is so made as to be
adapted to be charged with compressed air and to be held at its opposite ends only
and be freely exposed on its sides and capable of free lateral expansion and
contraction under the varying action of the load whereby a light spring having
both great weight supporting power and great range of elasticity is produced as
hereinafter described. The second feature of this invention consists in embedding
within the rubber or elastic walls of the hollow spring a sustaining web of canvas
or or other material arranged in a sinuous or fluted form which allows the spring
to expand to a great degree before any appreciable strain is exerted upon the web.
In the annexed drawings Figure 1 presents a side elevation of the improved
spring represented as held between its socket plates and bowed slightly under a
weight or in such form as it would normally assume when quiescent while the
dotted lines represent the flattening and outspreading of the spring under a great
weight or sudden jolt of the vehicle in which it might be used Figure 2 represents
a vertical section of the spring shown in its quiescent condition without being
under any weight Figure 3 is a cross section on X X and Figure 4 is a diagram
representing the position of the mesh in the sustaining web which is imbedded in
the walls of the spring
It will be seen on reference to the drawings that simply described, the spring is
a hollow elastic air vessel or cushion. I do not limit myself to any exact form or
size for this hollow elastic vessel or cushion but I have illustrated the forms and
proportion that are considered practically the best. The spring is preferably made
in a true cylindrical form of square proportion that is having an external diameter

page_text: equal to its extreme height as shewn well by Figures 2 and 3 The best size for
general railway use is found to be about 8 inches in both directions that is both in
diameter and height and in this size it is preferred to make the walls of the spring
or cushion both on the sides and on the ends, about an inch and a half thick
throughout, thus leaving a cylindrical cavity within measuring five inches by five.
These walls should of course be made of some strong and flexible or elastic material
such as vulcanized rubber. This spring is made in the usual manner in which
other hollow rubber articles are made viz, with a sustaining web or frame of canvas
or other suitable fabric embedded within its rubber walls as shown at b. c in
Figure 1 which pervades both the vertical sides and the heads of the cylinder as
illustrated. The edges or ends of the canvas in the sides of the cylinder are joined
or interlaced with the edges or ends of that in the ends at the corners or angles of
the cylinder as seen in Figure 2, thus forming a continuous frame or web within
the rubber walls as will be understood. It is preferred to use from three to seven
layers of canvas cemented closely to each other by thin films of rubber cement as
indicated in Figures 2 and 3 but more or less may be used.
I may now be seen on reference to Figure 3 that the canvas in the sides of the
cylinder is arranged in sinuous folds or flutes or in a scalloped form, which as will
be readily understood allows the rubber cylinder to expand or distend to a great
degree when under the stress of a sudden force as indicated by dotted lines in
Figure 1 before any tearing strain will be exerted on the canvas, and at the same
time the canvas firmly supports the rubber whether quiescent or under tension.
The canvas layers on the heads of the cylinder are laid flat or level as the heads
are designed to be practically non extensible in a radial direction.
It is also preferred to have the canvas in the sides of the cylinder cut on the bias
as indicated in Figure 4 which brings the woven mesh diagonal to the circum-
ference of the cylinder consequently the mesh possesses a great mobility or power
of circumferential extension and vertical contraction similar to a lazy tongs which
thus gives the spring great range of extension in the direction shown by dotted
lines in Figure 1 without positively straining the strands or threads of the canvas
but this I do not claim of itself.
In one end of the elastic cylinder as seen in Figure 2 is arranged a suitable
valve by which the cavity of the cylinder may be charged with compressed air or
gas to any desired pressure and then closed or sealed to retain the charge. This
valve consists of a seat or socket d having a broad flange embedded in the rubber
of the head and a neck or nipple f which extends inward and opens into the air
cavity. Into the socket is screwed a hollow valve plug e having at its lower end a
valve disc which is adapted to seat on the boss of the socket and cover the mouth
of the nipple fas shown. The valve plug has a broad flange hat the top which
may be seized by a pin wrench to screw the plug to or from its seat and it also has
a central bore into which is screwed the ends of a pipe i through which the com-
pressed air may be conveyed. The bore of the plug does not extend through to
the end but opens laterally therefrom into the cavity of the socket d from whence
the air will flow when the valve plug is raised from its seat, through the nipple f
into the cavity of the spring. The compressed air may thus be forced through the
pipe and valve into the cavity of the spring till accumulated to the desired pressure
when the air may be shut off and the plug e screwed down firmly to its seat after
which the air pipe i may be unscrewed and the spring is then ready for use.
It is preferred to charge the springs, when of the dimension before stated, with
air or other gas to a pressure of about 30 pounds to the square inch, but much less
than this may be used although it is not desirable to use much more. The pressure
will have little or no tendency to laterally distend the walls of the spring when
quiescent owing to their thickness and strength and to the fact that the pressure
on the ends longitudinally extend the spring about balances the lateral pressure
on the sides which tends to flatten it; hence the spring will retain substantially a
cylindrical shape when not under stress. It will thus be seen that the strong
internal pressure to which the spring is constantly subjected by reason of its

page_text: charge of compressed air gives it a great resistant or weight-supporting power over
what it would possess if charged simply with air at the atmospheric pressure while
at the same time its ratio and range of elasticity is precisely the same as it would
possess if charged with air only at the atmospheric density Hence springs of much
less size and weight of rubber may be made to perform the same or a much greater
duty than heretofore thereby conducing greatly to cheapness and compactness, as
well as efficiency for a hollow rubber spring charged with air or gas whether
atmospheric or compressed possesses a most constant and permanent quality of
elasticity.
When used in supporting the bodies of railway vehicles upon their trucks the
spring may be socketed between two plates K K Figure 1 having broad flat bearing
faces to abut against the flat ends of the cylindrical spring and with deep flaring
rims having nicely rounded edges which allow the spring to throw outwardly
when under stress as indicated by dotted lines in Figure 1 without presenting any
sharp or cutting edge to the rubber. One of the socket plates K is of course
affixed to the body of the vehicle and the other to the truck or one to the truck
and the other to the axle box as will be readily understood according to the
position in which the spring is used. The spring may of course be applied and
fixed in various ways according as it is employed as a "buffer" or "spring" which
attachments do not form any essential part of this invention and need no descrip
tion here. It will be noted however that in this invention the hollow rubber
vessel or air spring is held at the opposite ends only and that its sides are freely
exposed. Hence the spring is free to expand or contract laterally under the
varying stress of the load and its full range of elasticity is available whereas
heretofore the hollow compressed air spring has been enclosed around its sides by a
metal case and furthermore bound with metal rings to prevent or limit lateral
expansion. In the case referred to lateral expansion would be injurious to the
rubber spring as it was formed without a sustaining web or fabric in its walls.
Hence when forced to expand or contract vertically its range of elasticity is less
and there is added to the spring a great weight of metal in the compressing
plunger inclosing cylinder; and binding rings which render the spring much
heavier than a solid rubber spring and with less range of elasticity whereas the
important qualities which are secured in this spring are greater lightness and
greater elasticity and weight-supporting power, which features combine to render
is a distinct improvement in this line.
Instead of using the form of valve shown for sealing the spring any other
suitable one may be employed and if preferred the valve may be covered over and
completely concealed by rubber after the spring is charged. Instead of a metallic
valve the aperture through which the spring is charged may be sealed with a plug
of rubber forced into the same and cemented if preferred.
Having now described the nature of the said invention and the manner of
performing the same as communicated to me by my foreign correspondent I wish
it understood that what I claim and desire to protect under the hereinbefore in
part recited Letters Patent is:
First A hollow elastic air spring consisting of a hollow vessel of rubber or
equivalent charged with a mass of compressed air and held at its opposite
ends only with its sides free to expand and contract laterally under varying
stress substantially as herein set forth.
Second An improved air spring consisting of a complete hollow vessel of rubber
or equivalent formed with a sustaining web or fabric embedded in its walls
and having its cavity charged with compressed air and adapted to be held
at its opposite ends only and to be exposed on its sides for the lateral
expansion or contraction substantially as herein shown and described.
Third A spring buffer or cushion consisting of a hollow rubber and having flexible
or elastic walls constructed with a sustaining web or fabric embedded in its
walls and arranged in sinuous folds or flutes, substantially as and for the
purpose set forth

page_text: th-A hollow elastic spring of rubber or equivalent material constructed with
a sustaining web or fabric of canvas or equivalent woven material embedded
in its walls in sinuous folds or flutes with its mesh arranged diagonally or
bias to the walls of the spring whereby a greater mobility is obtained
without appreciably straining the fabric substantially as herein-shown and
described.
-A hollow elastic spring having its cavity charged with a confined mass of
air and its walls formed of suitable elastic material with a sustaining web
of fabric embedded in its walls pervading both the sides and ends of the
vessel and joined or interlaced at the corners or angles of the vessel forming
a continuous sustaining shell or frame within the elastic walls substantially
as and for the purpose set forth.
In Witness whereof I the said Alfred Julius Boult have hereunto set my band
and seal the Eighteenth day of September in the year of Our Lord One
thousand eight hundred and eighty two.
ALFRED J. BOULT. (L.S.)