IMPROVEMENTS IN BUFFER AND DRAW BAR APPARATUS FOR RAILWAY VEHICLES, PART OF THE INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES." PROVISIONAL SPECIFICATION
Year: 1879

page_text: LETTERS PATENT to Robert Henry Hepburn, of Llanelly, in the County of
Carmarthen, Locomotive Engineer, for the Invention of "IMPROVEMENTS IN
BUFFER AND DRAW BAR APPARATUS FOR RAILWAY VEHICLES, PART OF THE
INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Robert Henry Hepburn at
the Office of the Commissioners of Patents on the 23rd August 1879.
"
ROBERT HENRY HEPBURN, of Llanelly, in the County of Carmarthen, Locomotive
Engineer. IMPROVEMENTS IN BUFFER AND DRAW BAR APPARATUS FOR RAILWAY
VEHICLES, PART OF THE INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES."
My Invention has reference primarily to the buffer and draw bar apparatus of
railway vehicles, but some of the improvements are also applicable to other purposes,
as hereinafter mentioned.
In order to prevent "crushing" or overstraining the springs of buffers and draw
bar apparatus I employ a conical volute spring, the base or largest coil of which I
encircle by an expanding ring or clip piece, preferably of steel, forced on after the
manner in which a piston ring is forced on to a piston; this ring or clip piece is
of such a width that the push plate of the buffer or the draw plate of the draw
bar, or other corresponding device, comes upon it before the entire stroke of the
spring is absorbed, the ring thus acts as a stop, prevents overstraining or crushing
of the spring, and takes the strain off the buffer case. The large surface comprised
within the ring or stop has also the effect of saving the back plate, the strain or
pressure being widely distributed over it. The ring may be cheaply manufactured
by rolling crop ends of steel rails to a suitable section, and by then cutting into
proper lengths and bending into rings. The section of the rings may be varied to
suit special requirements; for example, in applying it to draw bar springs a rim or
step may be provided at the base to receive the draw plate, the spring will thus
be maintained in the direction of the line of action or force. Sometimes I make
the stop in the form of a cup to receive the first coil of the spring, a ring being
screwed or fixed to the edge of the cup so as to retain the spring therein, and at the
same time act as a stop. Sometimes again I make the spring and stop in one

page_text: piece by forming the bar from which the spring is to be manufactured wider and
of even width for that portion which will constitute the first or largest coil of the
spring (and where the wider coil runs into the next following narrower coil, the
difference between their respective widths is reduced by a gradual taper or any
other suitable angle which will give the necessary elasticity), this coil on account
of its extra width will act as a stop.
In some cases I make conical volute springs for buffers and draw bars with a
lip or projection on one or both of the edges whereby the resisting power is con-
siderably increased in proportion to the weight. The lip or projection on each
successive coil as it is driven in conveys the strain to the next following coil, the
force put upon the spring is thus more evenly distributed over the coils. In order
to allow of the dimensions and weights of the buffer case being considerably
reduced I prefer to employ, instead of the ordinary circular push plate or collar on
the plunger, a cross bar made in one piece with or fixed to the plunger. While the
length of this cross bar must equal or exceed the diameter of the stop to the spring
its thickness need only be such as is requisite for strength; therefore, as the outer
part of the buffer case can be shaped to correspond with the cross bar the dimen-
sions of the case may be reduced accordingly. For the purpose of giving increased.
strength or stiffness to the buffer case in proportion to its weight, more particularly
when of the form described in the Specification of former Letters Patent granted
to me and dated 25 January, 1876, No. 284, I make it in a corrugated form.
I also prefer to make the drawbar cradles in a corrugated form from plate steel
or iron pressed into shape by hydraulic or other power.
In order to permit of readily tightening up the slack of the draw bars and to
dispense with the use of spanners for the purpose I construct the draw bar cradle
with a fixed nut which works on a screw on the draw bar, so that by simply
causing the cradle to rotate by means of the band, or otherwise, the nut with the
cradle works along the bar and tightens up the slack. To allow the. cradles to
radiate to curves of the line, and thereby reduce the wear and tear of the vehicles,
I make them in halves, each half having apertures or eyes at its inner end to fit
over a vertical pin on which it can swivel; this pin when slack is being tightened
up, is free to travel longitudinally in horizontal guides or slots in top and bottom
plates.
Although the improved springs and stops for springs hereinbefore described have
been specially designed for buffer and draw bar apparatus they may also be applied.
with advantage to other purposes, as will be readily understood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Henry Hepburn in the Great 'Seal Patent Office on the 23rd
February 1880.
ROBERT HENRY HEPBURN, of Llanelly, in the County of Carmarthen, Locomotive
Engineer. "IMPROVEMENTS IN BUFFER AND DRAW BAR APPARATUS FOR RAILWAY
VEHICLES, PART OF THE INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES."
My Invention has reference primarily to the buffer and draw bar apparatus of
railway vehicles, but some of the improvements are also applicable to other
purposes, as hereinafter mentioned.
In order to prevent "crushing" or overstraining the springs of buffers and
draw bar apparatus I employ a conical volute spring, the base or largest coil of
which I encircle by an expanding ring or clip piece, preferably of steel forced on
after the manner in which a piston ring is forced on to a piston; this ring or
clip piece is of such a width that the push plate of the buffer or the draw plate
of the draw bar, or other corresponding device, comes upon it before the entire
stroke of the spring is absorbed, the ring thus acts as a stop, prevents overstraining
or crushing of the spring, and takes the strain off the buffer case. The large surface
comprised within the ring or stop has also the effect of saving the back plate, the
strain or pressure being widely distributed over it.
In Figures 1 and 2 of the annexed Drawings I show respectively two forms of
conical volute springs, the base or largest coil of which is encircled by a ring or
clip piece as hereinbefore described. In each Figure a is the spring and b the
ring or clip piece, which, as already explained, may be forced on after the
manner in which a piston ring is forced on to a piston. The width of the ring b,
that is to say, from 1 to 2, is such that the push plate of the draw bar or other
corresponding device comes upon it before the entire force of the spring is absorbed,
and therefore the ring acts as a stop, prevents overstraining or crushing of the
spring, and (when applied to buffers) takes the strain off the buffer case.
The ring may be cheaply manufactured by rolling crop ends of steel rails to a
suitable section, and by then cutting into proper lengths and bending into rings.
The section of the rings may be varied to suit special requirements; for example,
in applying it to draw bar springs a rim or step may be provided at the base to
receive the draw plate, as shown in Figure 3, in which c is the rim or step and d
represents the draw plate, the spring will thus be maintained in the direction of
the line of action or force. Sometimes I'make the stop, in the manner represented
in Figure 4, in the form of a cup e to receive the first coil of the spring a, a ring f
being screwed or fixed to the edge of the cup so as to retain the spring therein
and at the same time act as a stop. Sometimes, again, I make the spring and
stop in one piece, as shown in Figures 5 and 6, by forming the bar from which the
spring is to be manufactured wider and of even width for that portion which will
constitute the first or largest coil b, of the spring, and where the wider coil runs
into the next following narrower coil the difference between their respective widths
is reduced by a gradual taper or any other suitable angle which will give the
necessary elasticity; the first or largest coil on account of its extra width will act
as a stop, or instead of making the first or largest coil sufficiently, wide to form a
stop, as just described, I make the last or smallest coil sufficiently wide for this
purpose.
In some cases I make conical volute springs for buffers and draw bars with a
lip or projection on one or both of the edges whereby the resisting power is con-
siderably increased in proportion to the weight.. This improvement is represented
in Figure 7, a being the spring and g a lip or projection, which in the example is
shown on the inner edge. The lip or projection on each successive coil as it is

page_text: driven in conveys the strain to the next following coil, the force put upon the
spring is thus more evenly distributed over the coils.
In order to allow of the dimensions and weights of the buffer case being con-
siderably reduced I prefer to employ, instead of the ordinary circular push plate or
collar on the plunger, a cross bar made in one piece with or fixed to the plunger.
While the length of this cross bar must equal or exceed the diameter of the stop to
the spring its thickness need only be such as is requisite for strength; therefore,
as the outer part of the buffer case can be shaped to correspond with the cross bar
the dimensions of the case may be reduced accordingly. For the purpose of giving
increased strength or stiffness to the buffer case in proportion to its weight, more
particularly when of the form described in the Specification of former Letters
Patent granted to me and dated 25th January, 1876, No. 284, I make it in a
corrugated form. Figures 8, 9, 10, and 11 represent in elevation, longitudinal
section, end view, and transverse section respectively, a buffer case of the kind
described in my said former Specification, but modified in accordance with my
present Invention. Figure 12 represents in section the cross bar hereinbefore
described, together with a portion of the plunger to which it is fixed. h, h, are the
halves of the buffer case rivetted at their inner or back ends to the plate i, and
connected together at their outer ends by bolts or rivets k, as described in my said
former Specification. The halves h, h, are corrugated, as is clearly seen in the
Figures. These corrugations I form by pressure by means of hydraulic or other
power, and they terminate, as clearly seen in Figure 9, short of the flange by which
the halves are rivetted to the back plate i; is the cross bar hereinbefore described
fixed to (or it may be formed in a piece with) the plunger m The length of this
cross bar must equal or exceed the diameter of the stop to the spring. The stop b
and spring a seen in Figure 9 are the same as shown in Figure 7. The thickness
of the cross bar 1, as has been already stated, need only be such as is requisite for
strength.
I also prefer to make draw bar cradles in a corrugated form from plate steel or
iron pressed into shape by hydraulic or other power. Figure 13 represents in side
elevation and Figure 14 in end view a draw bar cradle made in a corrugated form
as just described. The cradle is shown as composed of upper and lower halves m, m,
with flanges n, n, at their ends, a bush o with flanges as shown being placed
between them and the whole secured by rivets P. P; or the flanges on the bush
may be dispensed with, in which case the flanges n, n, of the cradle will meet.
The cradle sides are brought down, as shown at j, j, to form a sort of cup so that
the spring when slack cannot drop or droop.
In order to permit of readily tightening up the slack. of the draw bars and to
dispense with the use of spanners for the purpose. I construct the draw bar cradle
m, m (whether made in halves or otherwise) with a fixed nut at q (which will be
formed in the bush o when such is used) which nut works on a screw on the
draw bar, so that by simply causing the cradle m, m, to rotate by means of the
hand or otherwise, the nut q with the cradle works along the bar and tightens up
the slack. To allow the cradles to:radiate to curves of the line and thereby reduce
the wear and tear of the vehicles I divide them transversely into halves, each half
having apertures or eyes at its inner end to fit over a vertical pin on which it can
swivel; this pin when slack is being tightened up is free to travel longitudinally in
horizontal guides or slots in top and bottom plates. Figures 15 and 16 represent
respectively in side elevation and plan a cradle made in halves as just described.
t, ti, are the halves with apertures or eyes at their inner ends to fit over a vertical
pin u on which each of the halves can swivel; this pin' when slack is being
tightened up is free to move longitudinally in horizontal guides or slots v, v, in top
and bottom plates w, w The right hand portion of Figure 16 shows the position
of the draw bars on a straight line of rail, and the left hand portion shows the
position of the draw bar on a curve, the corresponding half of the cradle having
swivelled on the pin u.
Although the improved springs and stops for springs hereinbefore described have

page_text: been specially designed for buffer and draw bar apparatus they may also be applied
with advantage to other purposes, as will be readily understood.
And having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim,―
First. Fitting conical volute springs for buffer and draw bar apparatus, or other
purposes, with a ring or clip piece to prevent crushing or overstraining, substan-
tially as hereinbefore described and shown in Figures 1 and 2 of the annexed
Drawings.
Second. In combination with the said ring or clip piece I claim the rim or step,
substantially as and for the purpose hereinbefore described and shown in Figure 3
of the annexed Drawings.
Third. Constructing stops for conical volute springs, substantially as shown in
Figure 4 of the annexed Drawings and hereinbefore described.
Fourth. Constructing conical volute springs with a stop formed in a piece there-
with, substantially as herein before described with reference to Figures 5 and 6 of
the annexed Drawings.
Fifth. Forming conical volute springs with a lip or projection on one or both of
the edges, substantially as herein before described and shown in Figure 7 of the
annexed Drawings.
Sixth The employment on buffer plungers of a cross bar, substantially as and
for the purpose hereinbefore described with reference to Figures 8 to 12 of the
annexed Drawings.
Seventh. Constructing buffer cases, substantially as hereinbefore described with
reference to Figures 8 to 12 of the annexed Drawings.
Eighth. Constructing corrugated draw bar cradles, substantially as hereinbefore
described with reference to Figures 13 and 14 of the annexed Drawings.
Ninth. Constructing draw bar [cradles with a nut which works on a screw on
the draw. bar, substantially as and for the purpose hereinbefore described and
shown in Figures 13 and 14 of the annexed Drawings.
Tenth. Constructing draw bar cradles in halves, and fitting the said halves so
that they are free to swivel to enable the draw bars to accommodate themselves to
curves in the line, substantially as hereinbefore described and shown in Figures 15
and 16 of the annexed Drawings.
In witness whereof, I, the said Robert Henry Hepburn, have hereunto set
my hand and seal, this Sixteenth day of February, One thousand eight
hundred and eighty.
R. H. HEPBURN. (L.S.)