Year: 1898

page_text: Date of Application, 3rd June, 1898
Complete Specification Left, 2nd Mar., 1899-Accepted, 22nd Apr.,
1899
Date of Application, ord June, rogo
Complete Specification Left, 2nd Mar., 1899-Accepted, 22nd Apr., 1899
We, THE WESTINGHOUSE BRAKE COMPANY LIMITED, of York Road, King's Cross,
in the County of London, Manufacturers, do hereby declare the nature of this
invention to be as follows:-
This invention relates to buffer and draw-bar apparatus and in particular to
apparatus of the kind described in the Specification of British Letters Patent
No. 14851, dated 6th August 1895, granted to the Westinghouse Brake Company,
Limited.
In the specification above mentioned there is described a device for expanding a
number of wedge-shaped bars in corresponding grooves in a casing when a buffing
or draught stress is applied to the buffer or draw-bar so that a frictional resistance
is opposed to the movement of the same.
The chief feature of the present invention consists in the provision of means
whereby the expanding device shall be withdrawn from operation when, but not
until, the maximum stress has been reduced and the application of the force
reversed, such releasing means being inert and disengaged from the expanding
device during the period of maximum stress.
A further important feature of the invention consists in providing that the
wedge-shaped bars shall be withdrawn from their corresponding grooves in suc-
cession instead of simultaneously upon the cessation of buffing or draught stres
whereby the reduction of the frictional resistance is facilitated.
In order that the nature of the invention may be clearly understood the applica-
tion of the same to the apparatus described in the Patent Specification above
referred to will now be indicated. The expanding device in said apparatus con-
sists of a conical or pyramidal ring or wedge-block which engages with a series of
segments forming a shell which carries wedge-bars. The movement of said ring
or wedge-block in one direction under a buffing or draught stress forces the seg-
ments of the shell and thereby the wedge bars outwards, causing the latter to
engage with the grooves in the casing. In order to effect the prompt withdrawal
of the ring or wedge-block from the shell when the stress is reduced, according
to the present invention a spring is provided which presses said ring away from
the segments, that is to say, in the opposite direction to that above mentioned,
thereby permitting the segments to readily collapse and move inwards withdrawing
the wedge bars from frictional contact with the grooves. Said spring is, how-
ever, prevented from pressing upon the ring during the period of maximum
stress by means of a pin or flanged sleeve which is interposed between said ring
and the end of the spring, which pin or sleeve is moved away from the ring so as
to compress the spring during the period referred to.

page_text: Like letters of reference refer to similar parts throughout the drawing.
Referring, now to Figures 1 and 3, A is the buffer head which is secured to the
casing E in which are provided longitudinal grooves substantially triangular in
cross-section for receiving the wedge-shaped friction bars F. The friction bars are
supported by carriers C, the tongue or projection f on each bar engaging with
corresponding recesses c in the carriers as shewn in Figures 7 and 8. Secured to
the buffer head and passing through the rear plate A¹ of the buffer is a rod A², and
concentric with said rod is a sleeve H provided with a ring H¹ forming a pyramidal
bearing surface as indicated in Figure 3, said ring which with the sleeve H, we
term the wedge block is surrounded by the inclined inner faces of the carriers C.
Said carriers are provided with spring ribs C. Springs B and D are interposed
between the rear faces of the wedge block H and the back plate of the buffer, and
the front face of the carriers C and the buffer head as shewn.
Buffers constructed in this manner are now well known, but according to the
present invention we introduce between the wedge block and the rod or shaft A2
passing through its centre, a sleeve S having a flange S', between which flange and
the buffer head is provided a spring T.
In the case of the draw-gear shewn in Figures 4 and 5, the bar L at one end is
connected through a cross head M and side rods N with a cross head M in engage-
ment with the spring B and the bar L' at the other end is connected through a
cross head U and side bars U with the cross head U2 attached to the outside
casing E and engaging with the spring D and releasing spring T. It will be
obvious that the operation of the buffer under a compressive stress and of the
draw-bar when a pulling force is applied to either end will be the same.
When stresses are applied to the apparatus illustrated, pressure is transmitted
through the spring D and the carriers C and wedge block H to the spring B
compressing same. The pressure between the springs D and B causes the carriers
to move relatively to the wedge block in the direction of the arrow in Figure 1
and said carriers are thereby forced outwards causing the friction bars F to engage
with their corresponding grooves in the outer casing. The friction between the
bars and the outer casing ultimately becomes so great as to prevent further
inward movement of the buffer head. The sleeve S which in the draw gear is
replaced by a pin as shewn, will follow the parts H H in their movement, until
its end 2 comes in contact with the back plate A of the buffer, when its further
movement will be arrested and the spring T compressed, the parts H H¹ being
thereby relieved from the pressure of the flange S¹. This position of the parts is
shewn in Figure 2 which illustrates the limiting position of the buffer under
pressure, and from which it will be seen that the releasing spring T is no longer
pressing on the expanding device.
On the cessation of the stress the springs B and D expand the entire apparatus
lengthwise and as soon as the parts H H have reached a sufficient distance from
the back plate their movement will be arrested by the flange S₁ of the sleeve S,
which under pressure of the spring T has retained its position shewn in Figure 2.
The carriers C, however, continue to move forward in the opposite direction to that
indicated by the arrow and their internal support being withdrawn will collapse
inwards thereby permitting the friction bars F to become disengaged from the
grooves in the casing E. Hence the positive withdrawal of the support from the
carriers is effected.
It will be readily understood without further description that the draw-bar
apparatus shewn in Figures 4 and 5 will operate in precisely the same manner as
that above described for the buffer if a tensile stress be applied to either end
the other end being fixed.
In order to release the friction bars F in succession from their corresponding
grooves in the casing E, lost motion is provided between the tenons f and the
corresponding recesses c in the carriers. Different bars are arranged to have
different amounts of lost motion so that said bars are moved in succession. In
Figures 7 and 8 longitudinal sections of a bar and its carrier plate are shewn and