Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
Field of Invention
~. _ .
This invention relates generally -to a drawbar assembly
for railway vehicles and particularly to a new and novel
drawbar assembly which resists misalignment of the vehicle
unit ends to which the drawbar is connected. The drawbar
S assembly has a substantially rigid drawbar member and a
buffing block means constructed so as to provide a turning
moment when operating under buff loading that tends to
maintain the two horizontally displaced adjacent ends of
railway vehicle units in alignment.
Prior Art
In present day practice, the standard length of the
containexs to be carried on flat bed railway cars is approxi-
mately 45 feet. Since the length of the longest flat bed
car is limited to about 89 feet, it cannot accommodate two
such containers. The construction of individual shorter
45 foot length flat bed cars each carrying one container is
costly and inefficient because each car would require yokes
and draft gear assemblies at each end. This inefficiency is
particularly apparent when the flat bed cars are employed
for carrying containers only and the cars are infrequently
disconnected. Accordingly, it has been proposed to provide
a flat car of 90 foot length including two sections or units
of which the adjacent ends are connected by a simple drawbar
assembly. The remote ends may be provided with the usual
couplers, yokes and cushioning draft gear. The construction
and the arrangement of a generally conventional drawbar
assembly under buff loading tends to create forces which may
jac~knife the two adjacent railway car sections.
-1- ' ~'
SUMMARY OF THE INVENT I ON
In accor~ance with the present inventlon, there is
provided a drawbar assembly for railway cars which overcomes
the jackknifing tendency of the railway cars as encountered
heretofore. This is accomplished generally by the provision
of a buffing block assembly and a drawbar which are constructed
and arranged so that during buff impact they are engaged to
transmit a coupling force upon the drawbar to maintain it
normal to the adjacent ends of two car units.
More specifically, the opposite ends of the drawbar are
connected to the ends of the car unit center sills by means
of a key slot arrangement so as to permit relative limited
pivotal movement of the car units relative to each other.
In a buff condition, the opposite ends of the drawbar are in
contact with the respective buffing blocks located in the
respective adjacent car unit center sills. Buff alignment
control is achieved by engaging the contacting faces of the
buffing blocks with the associated ends of the drawbar so
that the force on the drawbar is eccentric of the center
line of the drawbar. This provides a coupling force which
tends to force the drawbar into a position normal or perpen-
dicular to the unit ends.
Other objectives, features and advantages of the invention
will be apparent from the following detailed disclosure
taken in conjunction with the accompanying sheets of drawings
in which like parts bear like reference numerals~
~-2-
7~
In particular, the present invention provides a drawbar
arrangement for connecting the adjacent ends of two adjacent
railway vehicles each having a drawbar pocket and stop means
disposed within said drawbar pocket, a buffing block disposed
in each of said pockets and engageable with said stop means
upon buff impact of said vehicles, said buffing blocks each
having a planar buffing surface surrounded by a convex surface,
and an elongated drawbar having opposite ends extending into
respective ones of said drawbar pockets, key means connecting
said opposite ends of said drawbar in said drawbar pockets,
said drawbar ends each having a partially spherical surface and
a concentric planar surface normal to the longitudinal axis of
said drawbar, said spherical surface having a radius of cur-
vature greater than one-half the length of said drawbar and the
center of curvature thereof disposed on the longitudinal axis
of said drawbar whereby when said railway vehicles are in buff
condition and longitudinally axially aligned said drawbar planar
surface and said buffing block planar surface are in substan-
tially face to face engagement with said buffing block abutting
said stop means so that said buffing forces are transmitted
longitudinally through said drawbar and said railway cars, and
when said railway cars are in buff condition and out of longi-
tudinal axial alignment said drawbar spherical surface and said
convex buffing block surface are in engagement with s~id
buffing block abutting said stop means so as to impose said
buff forces on said drawbar ends on opposite side of said longi-
tudinal axis of said drawbar to cause said drawbar to become
aligned with the longitudinal axes of said vehicles and simul-
taneously to exert opposing forces on said adjacent vehicles to
cause the railway vehicles to become longitudinally aligned.
-2a-
ZC3~
BRIEF DESCRI~TION OF THE DRAWING~`~
Figure 1 is a fragmentary side elevational view of a
drawbar assembly connecting the two adjacent ends of two
sections of a railway car.
Figure 2 is a top plan view of a drawbar member embodying
S the present invention.
Figure 3 is a side elevational view of the drawbar
member of Figure 2.
Pigure 4 is an end elevational view of an end surface
of the drawbar member taken generally along line 4-4 of
Figure 2.
Figure 5 is a fragmentary and perspective view of a key
bearing block engaged with an end of the drawbar with some
of the parts broken away to show underlying details.
Figure 6 is a fragmentary top plan view, partially in
cross section, of a drawbar assembly showing one end of the
drawbar member in contact with the buffing block shown
engaged in the buff position.
Figure 7 is a frasmentary and schematic view of a
buffing block abutting an end surface of the drawbar showing
radius of curvature r and length dimension L.
Fisure 8 is a cross-sectional view taken along the
line 8-8 of Figure 6.
Figure 9 is a fragmentary side elevational view taken
generally along line 9-9 of Figure 6.
Figure 10 is an end elevational view of a load bearing
surface of the buffing block taken generally along
line 10-10 of Figure 9.
--3--
1~7Z~
Figure ll is a fraqmentary and schematic top plan view
of the drawbar assembly and showing the forces on acting
thereon in ~he buff position.
DESCRIPTION OF THE P~EFERRED EMBODIMENT
Referring now to the drawings, in particular Figure 1,
there is shown a drawbar assembly 10 connecting the adjacent
ends of two units 12 and 14 of a flat bed railway vehicle
16. While the drawbar assembly is shown only connecting the
adjacent ends of two units of a railway car, it should be
readily apparent that the units may be two independent cars
and the drawbar assembly may be utilized at each end of such
cars or units.
The railway vehicle units 12 and 14 may be of generally
con~entional structure including an underframe having a
center sill 18 and flooring 19 supported thereon. Containers
or semutrailers, each which may be of the standard 45 'oot
length, are supportable on the units 12 and 14. The re~ote
ends of the railway vehicle 16 are provided with the usual
coupler, yoke and draft gear assemblies (not shown).
The center sills 18 may each be of generally conventional
hat-shaped structure along the major portion of the length
thereof and provided at one end wlth a drawbar pocket 20 as
shown in Figures 6, 8 and 9. The drawbar pocket 20 is
defined by a top web 22 and two side webs 24. Two substan-
tially opposed buff stops 26 are integrally formed on the
side webs 23 of pocket inserts 25 welded to the side webs 24
of the center sill 18 in the drawbar pocket 20. The ~uff
stops are reinforced by gussets 28 fixed to the sidewalls 23
~L~.72~8
of the insert 25. A portion of each side web 24 and the
insert 25 defines a generally oblong-shaped keyway opening
30 along each slde of the pocket 20. The size of the keyway
opening 30 is generally larger than that of the cross-
sectional area of a conventional horizontal key 32.
Figures 2 to 4 show a drawbar 10 which is made of metal
and of generally rectangular cross sectlon along its length
having a top panel 33 and a bottom panel 3.5 and sidewalls 37
and 39. The drawbar 10 further has enlarged terminal
portions 34 also of rectangular section at each end thereof.
The terminal portions 34 are formed with terminal faces 36
having a generally convex spherical surface 38 and a planar
circular surface 40 concentric with the longitudinal axis
L-L of the drawbar.
In accordance with the present invention, the radius of
curvature r of the convex spherical surface is at least half
the length L of the drawbar 10 as defined by the distance
between the terminal circular faces 40 at the opposite ends
of the drawbar. The relationship of the radius of curvature r
of the convex spherical surface 38 and the length of the
drawbar L is significant for reasons which will become
apparent hereinafter.
As shown in Figure 3, portions of the sidewalls 37 and
39 adjacent to the ends of the drawbar define two aligned
key slot openings 42 each being of a longitudinal wedge
shape with an area larger than the cross-sectional area of a
horizontal key 32. The upper and lower portions of the key
slot opening form a slightly divergent angle so that the
wider portion of the wedge-shaped opening is closer to
~7~
the center of the drawbar and the narrower portion adjacent
the terminal portion 34. The terminal portion 34 adjacent
the key siot openings 42 generally includes a horizontally
radially convex and vertlcally radialiy concave surface 43
so as to complementally abut front surface 45 of key bearing
block 44 to be described hereinafter.
A key bearing block 44 is located in the key slot
opening 42 of the drawbar 10 between the end portion 34 and
the horizontal key 32. The key bearing block 44 generally
includes a front horizontally radially concave and vertically
radially convex surface 45, a rear horizontally linear and
vertically radially concave surface 47 and two inclined side
edges 49 as shown in particular in ~igures 2, 3 and 5. The
front surface 45 of the key bearing block 44 is defined as
the surface adjacent the terminal portion 34 of the drawbar
10 and the rear surface 47 is defined as the surface adjacent
the horizontal key 32. The key bearing block 44 further has
two substantially opposed downwardly extending retainer tabs
46 along its side edges 49 spaced at a distance greater than
the distance between the sidewalls 37 and 39 of the drawbar
10 .
Figures 2, 3 and 8 show generally a vertical support
pad assembly 48 including a nut 62, bolt 64 and removable
pad 66 arrangement through the top panel 33 of the dra~bar
extending into the upper portion of the key slot opening 42.
The functions of the support pad assembly will be described
hereinafter.
A plurality of oblong-shaped lightening apertures 54
are located on the top panel 33 and bottom panel 35 and a
--6--
~ ~t7~ Zc~
plurality of similarly str~ctured lightening apertures 56
are located on the sidewalls 37 and 39 of the drawbar 10.
A buffing block 50 is disposed in the drawbar pocket 20
and is located between buff stops 26 and the terminal end
portion 34 of the drawbar 10. The buffing block 50 includes
a face having a stop surface 51 abutting against the buff
stops 26 and a plurality of projections 52 for providing
structural strength. On its opposite face the buffing block
50 is formed with a buffing surface 53 including a generally
convex spherical surface 58 having a radius of curvature r'
and a planar circular surface 60 having substantiallv the
same diameter d as the surface 40 on the drawbar 10 concentric
with the longitudinal axis of the buffing block 50. The
buffing block 50 is fastened to the buff stops 26 by bolts
or welding~ It should be noted that the buffing block can
be fastened by other means, e.g. resiliently mounted to the
buff stops so as to reduce free slack between the drawbar
terminal face 36 and the buffing surface 53 of the buffing
block 50.
The drawbar 10 is held and supported in the drawbar
pocket 20 of the railway car center sill 18 by a horizontal
key 32 extending through the keyway opening 30 of the center
sill 18 and the key slot.opening 42 of the drawbar 10. When
two adjacent ends of railway cars are in a buff position,
the drawbar pockets 20 of car center sills 18 each having a
buffing block 50 disposed therein are being pushed towards
each other. ~he buffing surface 53 of each buffing block 50
becomes engasable with the respectlve terminal face 36 of
the drawbar 10. Under this condition, a buff force F is
exerted by the buffing block 50 on the drawbar 10 at the
--7--
1:~72Z(?t 3
terminaL surface 36 in a direction towards the center of
curvature of the convex spherical surface 38, as Figure 11
schematically illustrates. With the radius of curvature r
of the convex spherical surface 38 at least half the length L
of the drawbar, -the two e~ual forces exerted by the buffing
blocks 50 on both ends of the drawbar 10 form a coupling
that continues to reduce the degree of angling between the
drawbar 10 and the buffing block 50 until the longitudinal
axes of the drawbar 10 and the buffing blocks 50 are aligned.
As a result thereof, the adjacent railway vehicles 16 are
placed in an aligned position. The optimum radii of curva-
ture r of the convex spherical surface 38 of the drawbar 10
and r' of the convex spherical surface 58 of the buffing
block 50 are about the length L of the drawbar 10 so as to
maximize horizontal angling while retaining an aligning moment.
It should be noted that during the buff loading the
horizontal key 32 and key bearing block 44 remain loose in
key slot opening 42. As shown in Figure 6, the drawbar 10
is positioned at a horizontal angle with respect to the
buffing block 50. This may be the result of the railway
vehicles traveling on a curved track or from a yawing or
pitching motion of the vehicles.
The structure of the buffing surface 53 of the buffing
block 50 is substantially similar to that of the terminal
surface 36 of the drawbar so as to accommodate a horizontal
angle of about 9 between the longitudinal axes of the
drawbar 10 and the buffing block 50.
It should be understood that in a normal buff position
where the adjacent units of the railway vehicle 16 are
--8--
1~7~2(~13
aligned, the planar circular surrace 40 of the terminal
surface 36 has a sufficiently large area so as to provide
ample buff bearing area to accommodate the maximum loading.
For example, the diameter d of the planar circular surface
40 may be between four to seven inches.
Upon draft loading on the drawbar assembly, car center
sill 18 pulls the horizontal key 32 along the edge closer to
the end of the center slll 18. The opposite edge of the
horizontal key 32 transmits the pulling force to the drawbar
10 through the key bearing block 44.
The rear surface 47 of the key bearing block 44 has a
vertically concave groove that complementally abuts the
front edge of the horizontal key 32 permitting relative
vertical angling between the key and the drawbar 10. The
lS front surface 45 of the key bearing block 44 i5 horizontally
radially concave and complementarily abuts a portion of the
drawbar 10 so that relative horizontal angling between the
key bearing block 44 and the drawbar 10 is permitted. The
arcuate and complementarily formed interface between the key
2.0 bearing block 44 and the drawbar 10 provides a constant
pressure so as to reduce excessive and uneven we~r on the
drawbar as well as the key bearing block, even when the
drawbar 10 is at a horizontal angle with respect to the
longitudinal axis of the car center sill 1~.
It should be noted that the key bearing block 44 has
one downwardly dependent retainer tab 46 on each side of the
key bearing block 44 so as to prevent said block being
inadvertently dropped out of the key slot opening 42~
Another feature of the preferred embodiment is the
vertical support pad assembly 48 having a removable resilient
~L~7Z~Z(9~3
pad 66 retained by a nut 62 and a bolt 64 which supports
drawbar 10 and provides for concentricity of the cylindrical
edge of key 32 and rear surface 47 of key bearing block 44.
It also controls the longitudinal movement of ke~ bearing
bloc~ 44 particularly when clearance exists adjacent the key
32 when the drawbar 10 is in buff.
--10--
