Note: Descriptions are shown in the official language in which they were submitted.
FITTING FOR AUTORACK RAILROAD CAR HOUSING
Field of the Invention
[0001] The
various inventive aspects and features herein relate to the field of railroad
freight cars, of which one example is field of railroad freight cars for
carrying automotive
vehicles, this kind of car being referred to in the industry as an "autorack"
car.
Background
[00021
Modern autorack cars, which is to say autorack cars built since about 1975 for
carrying automobiles, trucks or other vehicles in a multiple deck arrangement,
have typically
had the structure of a flat car underframe covered by a surface defining a
main deck for
supporting automotive vehicles. Most typically an upstanding elevated-deck
supporting
framework is mounted to the underframe. Since about 1975 the framework has
usually been
enclosed within, or used also to support a barn-like housing structure, which
may be referred
to as a closure system. Closure systems may include side screens, roof, and
end closures,
typically in the form of movable doors, the better to discourage thieves and
vandals. This
superstructure is typically referred to collectively as the "rack" of the
autorack. Most
typically the framework structure includes a series of vertical posts spaced
along the sides of
the car, with diagonal bracing or shear web panels between the posts, as may
be, and one or
two additional decks spaced upwardly from the main deck, and upon which
respective
second and third layers of automotive vehicles may be transported. That is,
the rack may be
a hi-level rack (i.e., a single elevated deck spaced upwardly above the main
deck of the
underframe) or a tri-level rack (two upper decks rather than one). The cars
tend to be as tall
as permitted under the applicable AAR plate clearance diagrams, for this car
type, mainly
Plate
and Plate 'IC, with maximum heights above Top of Rail or 19'-0" and 20'-3"
respectively. The housing may tend to have gable ends and bridge plates that
are movable to
an extended position to span the gap between adjacent cars during loading and
unloading.
Those end closures, when open, permit circus loading of the cars, i.e.,
sequential loading of
the automotive vehicles by driving in one end, and out the other on arrival.
Although other
kinds of end closures arc known, most typically radial arm doors are mounted
at the ends and
are movable between open and closed positions to govern loading and unloading
of the cars.
The racks are typically replaced twice during the economic life of the
autorack car
underframe. That is, the old rack is removed from the underframe and replaced
with a new
set of racks.
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100031 Racks have doors. They may be folding doors, as shown and
described herein.
The folding doors may have two or more panels that are connected together in a
hinged
relationship permitting mutual angular deflection during door opening and
closing. The
panels of the door may tend to be rather long, and may tend to be prone to
vibrate. One
particular mode of vibration that may be observed is longitudinal vibration
(i.e., the
excursion is in the rolling direction of the car), at the lowest natural
frequency of the panel.
[0004] It may be that the doors have access fittings, such as ladders
or rungs defining
ladders, mounted thereto for the purpose of permitting railroad personnel to
ascend the
various decks. It may also be that under certain operating conditions it may
be desirable to
have those access fittings in one configuration, such as a withdrawn,
retracted, or stowed
condition, while under other operating conditions it may be desirable for
those fittings to be
in a deployed or extended configuration.
Summary of the Invention
[0005] Among the various inventive aspects and features herein, in an
aspect of the
invention there is an autorack railroad car for rolling motion in a
longitudinal direction along
railroad tracks. That autorack railroad car has a main deck; a first elevated
deck spaced
upwardly from the main deck; and a housing enclosing the main deck and the
first elevated
deck. The housing includes a roof spaced upwardly of the first elevated deck.
The housing
has an access-way at a first end thereof through which to conduct wheeled
vehicles onto the
main deck and the first elevated deck. The car has at least a door movable to
govern access
to the housing. The door is a folding door hingedly movable relative to the
housing, the door
having at least a first panel and a second panel hingedly connected together.
The door has an
upstanding first margin and an upstanding second edge margin. When the door is
in a closed
position the upstanding second edge margin is laterally inboard of the
upstanding first
margin. A dynamic response member is positioned height-wise intermediate the
main deck
and the roof, and laterally inboard of the upstanding first margin. In the
closed position of
the door the dynamic response member impedes primary mode vibration of the
door in the
longitudinal direction.
[00061 In a feature of that aspect of the invention the dynamic
response member is
positioned longitudinally between the first elevated deck and the door. In
another feature, at
least a first portion of the dynamic response member is mounted to the first
elevated deck. In
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still another feature, a second portion of the dynamic response member is
mounted to the
door. In a further feature, the first and second portions of the dynamic
response member
interact. In still another feature, when the door is closed, the dynamic
response member is
longitudinally pre-loaded in the longitudinal direction. In a further feature,
the dynamic
response member comprises a damper.
[0007] In another feature, the dynamic response member defines a
vibration nodal point
intermediate the main deck and the roof. In still another feature, the dynamic
response
member is mounted between the first elevated deck and the door with a
clearance in the
range of 0" to 1/8", and with no longitudinal pre-load of the dynamic response
member. In
another feature, the dynamic response member has a first portion mounted to
one of (a) the
door, and (b) the first elevated deck; and a second portion mounted to the
other of (a) the first
elevated deck, and (b) the door; the first and second portions of the deck are
mounted to work
co-operably in opposition to each other; and the first portion includes a
damping material and
the second portion defines a seat positioned for engagement by the damping
material.
[0008] In another feature, there is a second dynamic response member,
the second
dynamic response member being spaced height-wise from the first dynamic
response
member and intermediate the first dynamic response member and the roof In a
further
additional feature, there is a second elevated deck spaced upwardly from the
first elevated
deck. The roof is spaced upwardly of the second elevated deck. The door has an
upstanding
first margin and an upstanding second edge margin. The first dynamic response
member is
mounted to work between the door and the first elevated deck. The second
dynamic response
member is mounted to work between the door and the second elevated deck. In a
still further
feature, the first and second dynamic response members include a damper.
[00091 In still another feature, the door is a first door, the car has
a mating second door,
and the first and second doors are co-operable to govern access to the first
end of the
housing. In another feature, the dynamic response member is positioned
longitudinally
between the first elevated deck and the door. At least a first portion of the
dynamic response
member is mounted to the first elevated deck. A second portion of the dynamic
response
member is mounted to the door. The first and second portions of the dynamic
response
member interact. One of the first and second portions includes a damper. When
the door is
closed, the first panel is laterally outboard of the second panel. The dynamic
response
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member is mounted to the second panel. In a further feature, the dynamic
response member
defines a vibration nodal point intermediate the main deck and the roof.
[0010] In another aspect of the invention there is an autorack
railroad car having a main
deck; a first elevated deck spaced upwardly from the main deck; and a housing
enclosing the
main deck and the first elevated deck. The housing includes a roof spaced
upwardly of the
first elevated deck. The housing has an entryway at a first end thereof
through which to
conduct wheeled vehicles onto the main deck and the first elevated deck. There
is a door
movable to govern access to the housing. The door has an upstanding root
margin and an
upstanding free edge margin. When the door is in a closed position the
upstanding free-edge
margin is laterally inboard of the upstanding root margin. The door has an
overall height, the
overall height defining a span associated with a primary mode natural
frequency of vibration.
When the door is in the closed position the door engages the first elevated
deck, the
engagement sub-divides the span, whereby the door is inhibited from vibrating
in the primary
mode.
100111 In a further aspect of the invention, there is an autorack
railroad car having a main
deck; a first elevated deck spaced upwardly from the main deck; a housing
enclosing the
main deck and the first elevated deck. The housing includes a roof spaced
upwardly of the
first elevated deck. The housing has an entryway at a first end thereof
through which to
conduct wheeled vehicles onto the main deck and the first elevated deck. The
car has a door
movable to govern access to the housing. The door has an upstanding distant
margin. The
door has a first nodal engagement adjacent to the main deck. The door has a
second nodal
engagement adjacent to the roof. When the door is closed, the distant margin
of the door has
a third nodal engagement with the first elevated deck heightwise intermediate
the first and
second nodal engagements.
[0012] These and other inventive aspects and features may be
understood with reference
to the description which follows, and with the aid of the illustrations.
Brief Description of the Figures
[0013] The description is accompanied by a set of illustrative Figures
in which:
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100141 Figure la is a general arrangement, side view of an autorack
railroad car
according to an aspect of the invention;
100151 Figure lb is an end view of the autorack railroad car of Figure
la;
[0016] Figure lc is an isometric view of the autorack railroad freight
car of Figure la
without trucks; with housing side panels and roof panels removed to show
internal structure, and with the end portions of the mid-level deck removed;
[0017] Figure id is a perspective view, from below, of one half of the
autorack railroad
car structure of Figure le;
[0018] Figure 2a is an isometric view of a section of deck for use in
an autorack railroad
car such as that of Figures la, lb, lc and id;
[0019] Figure 2b is a half end view of one half of the section of deck
of Figure 2a;
[0020] Figure 2c is a half sectional view taken on section 2c ¨ 2c' of
the deck of Figure
2a;
[0021] Figure 2d is a side view showing a detail of the deck assembly
of Figure 2a;
[0022] Figure 2e is an upwardly looking view of the detail of Figure 2d;
[0023] Figure 3a is an isometric view of a stringer of the deck
assembly of Figure 2a;
[0024] Figure 3b shows an end view of the stringer of Figure 3a;
[0025] Figure 4a shows an isometric view of an end portion of the
autorack railroad car
of Figure la with its doors in the closed position;
[0026] Figure 4b shows an isometric view of the end portion of the autorack
railroad car
of Figure 4a with its left door in the open position and right door removed;
[0027] Figure 5a is a view taken on a vertical section '5a ¨ 5a' of an
end door of the
autorack railroad car of Figure 4a;
[0028] Figure 5b is an enlarged view of a detail of the view of Figure
5a showing a
vibration damper installation at the level of an upper elevated deck;
[0029] Figure 5e is an enlarged view of a detail of the view of Figure
5a showing a
vibration damper installation at the level of a mid-level upper deck;
[0030] Figure 6a is a sectional view taken on a vertical section taken
on section '6a ¨ 6a'
of an end door of the autorack railroad car of Figure 4a;
[0031] Figure 6b is an enlarged view of a detail of the view of Figure 6a
showing a
vibration damper installation at the level of an upper elevated deck;
[0032] Figure 6c is an enlarged view of a detail of the view of Figure
6a showing a
vibration damper installation at the level of a mid-level upper deck; and
[0033] Figure 6d is an isometric view of a bumper pad element for use
in the autorack
railroad car of Figure 4a;
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100341 Figure 7a is an isometric view of a movable step assembly in a
retracted position;
[0035] Figure 7b is an isometric view of the movable step assembly of
Figure 7a in a
transitional condition;
[0036] Figure 7c is an isometric view of the movable step assembly of
Figure 7a in a
deployed or extended position;
[0037] Figure 8a is an isometric view of a bracket of the step
assembly of Figure 7a;
[0038] Figure 8b is a front view of the bracket of Figure 8a; and
[0039] Figure 8c is a side view of the bracket of Figure 8a.
Detailed Description
[0040] The description that follows, and the embodiments described
therein, are provided
by way of illustration of an example, or examples, of particular embodiments
of the
principles, aspects or features of the present invention. These examples are
provided for the
purposes of explanation, and not of limitation, of those principles and of the
invention. In the
description, like parts are marked throughout the specification and the
drawings with the
same respective reference numerals. The drawings may be taken as being to
scale unless
noted otherwise.
[0041] The terminology used in this specification is thought to be
consistent with the
customary and ordinary meanings of those terms as they would be understood by
a person of
ordinary skill in the railroad industry in North America. The Applicant
expressly excludes
all interpretations that are inconsistent with this specification, and, in
particular, expressly
excludes any interpretation of the claims or the language used in this
specification such as
may be made in the USPTO, or in any other Patent Office, other than those
interpretations for
which express support can be demonstrated in this specification or in
objective evidence of
record, (for example, earlier publications by persons not employed by the
USPTO or any
other Patent Office), demonstrating how the terms are used and understood by
persons of
ordinary skill in the art, or by way of expert evidence of a person or persons
of at least 10
years' experience in the railroad industry in North America or in other former
territories of
the British Empire and Commonwealth.
[0042] In terms of general orientation and directional nomenclature,
for railroad cars
described herein the longitudinal or lengthwise direction is defined as being
coincident with
the rolling direction of the railroad car, or railroad car unit, when located
on tangent (that is,
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straight) track. In the case of a railroad car having a center sill, be it a
stub sill or a straight-
through center sill, the longitudinal direction is parallel to the center
sill, and parallel to the
top chords and side sills, as may be. Unless otherwise noted, vertical, or
upward and
downward, are terms that use top of rail, TOR, as a datum. In the context of
the car as a
whole, the terms cross-wise, lateral, or laterally outboard, or transverse, or
transversely
outboard refer to a distance or orientation relative to the longitudinal
centerline of the
railroad car, or car unit, or of the centerline of a centerplate at a truck
center. The term
"longitudinally inboard", or "longitudinally outboard" is a distance taken
relative to a mid-
span lateral section of the car, or car unit. The commonly used engineering
terms "proud",
"flush" and "shy" may be used herein to denote items that, respectively,
protrude beyond an
adjacent element, are level with an adjacent element, or do not extend as far
as an adjacent
element, the terms corresponding conceptually to the conditions of "greater
than", "equal to"
and "less than". The directions correspond generally to a Cartesian frame of
reference in
which the x-direction is longitudinal, the y-direction is lateral, and the z-
direction is vertical.
Pitching motion is angular motion of a railcar unit about a horizontal axis
perpendicular to
the longitudinal direction. Yawing is angular motion about a vertical axis.
Roll is angular
motion about the longitudinal axis. Given that the railroad car described
herein may tend to
have both longitudinal and transverse axes of symmetry, a description of one
half of the car
may generally also be intended to describe the other half as well, allowing
for differences
between right hand and left hand parts. In this description, if used, the
abbreviation kpsi
stands for thousands of pounds per square inch.
[0043] In this discussion it may by understood that persons of
ordinary skill in the art are
familiar with the Rules and Standards of the Association of American Railroads
(the AAR),
which govern interchange service in North America. This specification or the
accompanying
illustrations may refer to standards of the Association of American Railroads
(AAR), such as
to AAR plate sizes. To the extent necessary or appropriate, those references
are to be
interpreted in a manner consistent with the Rules and Standards as extant on
the earliest of
the date of filing of this application or the date of priority of the earliest
application from
which this application claims priority, as if they formed part of this
specification on that date.
[0044] Also for the purposes of the present discussion, it may be
taken as a default that
the structure of the car is of all-welded mild steel fabrication except as
otherwise shown in
the illustrations or indicated in the text. This need not necessarily be the
case. Other
materials, such as aluminum or stainless steel might be used. The rack
structure may also be
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taken as being of steel fabrication, although, again, aluminum or stainless
steel might be
used, and the side web panels of the car, which may be made of mild steel,
stainless steel, or
aluminum might also be made from plastic composite material, which may be
reinforced
composite. The commonly used engineering terms "proud", "flush" and "shy" may
be used
herein to denote items that, respectively, protrude beyond an adjacent
element, are level with
an adjacent element, or do not extend as far as an adjacent element, the terms
corresponding
conceptually to the conditions of "greater than", "equal to" and "less than".
[0045] In this description there is a discussion of doors. Autorcak
cars are known to use
at least three kinds of end doors to permit circus loading. The first kind of
door is a tracked,
multi-panel movable door such as shown in US 4,437,410 of Stoller, which has a
sequence of
panels that roll generally laterally along a typically non-circular arc track.
A second kind of
door is the radial arm door, invented by Blunden, and shown in various forms
in US
3,995,563; and in a later version in US 6,289,822 of Black et al. A third kind
of door is the
multi-folding door, typically either a hi-folding or tri-folding door, such as
shown in US
3,996,860 of Ravani, or in a later version, in US 6,289,822 of Black, Jr., et
al., or in US
7,802,525 of Dawson et al. In the typical case, whichever kind of door may be
used, the
doors are mounted in left and right hand halves, and the pairs of doors are
movable generally
laterally outboard to an open position facilitating access to the interior of
the autorack, and
generally laterally inboard to a closed position impeding access to the car.
Considering the
closed position as the datum, the door, of whatever type, may have an
upstanding outboard
margin at, or near, the upstanding side wall of the housing structure of the
car, and an
opposed upstanding inboard margin located generally at, or near, the
longitudinal centerline
plane of the car where it meets the corresponding inboard margin of the door
on the other
side of the car. In this description, the outboard upstanding edge may be
termed the root
edge, or the proximate edge or margin, or the staff edge or margin; the
inboard margin may
be termed the free edge or free margin, the distal edge or distal margin, or
the distaff edge or
distaff margin.
[0046] Also, in this description there may be discussion of modes of
vibration. In
general, an object may have a different natural frequency in vibration for
each degree-of-
freedom, be it translational or rotational, and there may be a plurality of
modes of vibration
for each degree-of-freedom. In each degree-of-freedom, the primary mode of
vibration is
typically the mode having the lowest natural frequency. Secondary, tertiary,
and higher
modes may correspond to higher frequency modes of vibration. Of all of the
possible
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degrees of freedom of the part or assembly, the lowest natural frequency is
typically the
dominant resonant natural frequency of the structure, and, for the purposes of
this discussion
will be taken as the primary natural frequency mode of the structure.
[0047] In Figures la ¨ id, an autorack railroad car is shown generally as
20. It has an
underframe, or underframe assembly, indicated generally as 22, that is carried
upon railroad
car trucks 24 for rolling motion in a longitudinal or lengthwise direction
along railroad
tracks. Underframe 22 is surmounted by an overspanning housing structure
indicated
generally as 26, and which may be referred to as "the rack" or "racks" of the
car. The ends
of housing structure 26 are open to permit loading and unloading of automotive
vehicles.
Ingress and egress of those vehicles is governed by a pair of end doors, 28,
such as may be
radial arm doors or multiply-folding movable between open and closed
positions.
[0048] Underframe 22 has a center sill 30. Center sill 30 is a
"straight through" center
sill that runs substantially entire length of the car between first and second
ends 32, 34 at
which strikers 36 are mounted. The main deck 40 extends to either side of the
center sill to
the sides of the car at side sills 42, 44. The term "straight through" is used
in distinction to
stub center sills such as used in, e.g., grain cars, where the center sill at
each end of the car is
truncated inboard of the center plate to leave a "stub", namely the center
plate and draft sill
assembly. In a straight through center sill, the center sill extends from one
truck center to the
other. The outboard portions of the center sill may be identified as the draft
sills 38 in which
the draft gear and couplers are mounted. Draft sills 38 are extensions of
center sill 30 that
extend longitudinally outboard of (and often include) the truck center to the
striker 36.
[0049] Side sills 42, 44 run lengthwise along either side of underframe
assembly 22, and
are structurally connected to center sill 30 by an array of laterally
extending structural
members which may include cross-bearers 46 and cross-ties (not shown). A cross-
bearer is a
beam having a first end connected to the center sill at a connection that is
intended to be
capable of transmitting a bending moment, such that the cross-bearer is also a
cantilever that
has its root, or built-in end at the center sill. The second end or distal end
or transversely
outboard end of each cross-bearer is connected to the associated side sill
running along that
side of the car. The side sills are themselves beams, typically of hollow or
open section,
formed with an upper flange, a lower flange, and a medial portion that
functions as a web to
carry shear between the upper and lower flanges. Side sills may sometimes have
a somewhat
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C-shaped section, with the open part of the C facing toward the center sill
and the webs of
the cross-bearer and cross-ties extending into the C and forming a connection.
[0050] Main deck 40 typically extends across the car from side sill to
side sill and from
end to end of the car, and provides a driving pathway for wheeled vehicles,
i.e., the lading for
this kind of car. Main deck 40 is supported by side sills 42, 44, center sill
30, cross-bearers
46 and such cross-ties as may be, and may form the top flange of one or more
of them. In the
example illustrated, for example, main deck 40 forms, or is substantially
flush with the top
cover plate (i.e., top flange) of center sill 30, over most or all of its
length e.g., excluding
draft sills 38. The main deck may also form the top flange of the cross-
bearers 46 and cross-
ties (if any). The main deck is open at the ends (i.e., the curbs defined by
the side sills only
run along the sides) such that wheeled vehicles may be end-loaded.
[0051] Looking at the framework of housing structure 26, housing
structure 26 includes
an array, or a series, of upstanding posts 50. That are spaced along the left
and right hand
sides of the car, i.e., along, and standing upwardly of, side sills 42 and 44
respectively.
There is an end framing structure, indicated as 52, that extends upwardly from
the ends of the
end sill, and which defines the shape of the gable end. Next inboard is "the
first post", an
upright side post 54 that runs between the side sill and the top chord at the
station of the first
lateral cross-members. Next inboard are posts 56, mounted at the ends of the
first lateral
frame (i.e., outboard of the truck center), and posts 58, mounted near the
ends of the second
lateral frame member inboard of the truck center. Posts 60 are mounted further
inboard at
the ends of the respective cross-bearers 46 that extend laterally of central
portion 48 of center
sill 30. Diagonal shear bracing 61, 62 is mounted between main posts 58 and
next
longitudinally inboard posts 60. Longitudinally running left and right top
chords 64 run
along, and tie together, the tops of all of posts 54, 56, 58, and 60 as may
be. The roof
structure 66 is mounted atop top chords 64 and restrains them in the lateral
direction, and
provides a lateral shear connection between the left and right hand side walls
67, 68 of the
car. The roof structure includes a framework of lateral frames and
longitudinal stringers (not
shown). This framework and the stringer form a truss structure that cooperates
with the truss
structure of the side wall posts. The framework may support one or more
elevated decks,
such as a second or mid-level deck 70, and a third or upper deck 72. The
entire structure
includes side wall panels 74 that are mounted between the various posts, and
that may tend to
act as shear panels between those posts and between the side sills 42, 44 and
the respective
top chords 64.
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100521 When the replaceable rack structure of posts and braces and top
chords is in place,
the high longitudinal members act as chords of a truss more than 10 ft.
distant from the side
sills. This deep truss structure provides the car with the resistance to
vertical bending
required when carrying lading in service. As noted above, the underframe is
intended to
define, and to be, permanent structure of the autorack car, whereas the racks
may have
roughly one third the life of the underframe. That is, the underframe may be
provided with a
first set of racks when new, and then with a further two sets of replacement
racks during the
car's lifetime.
[00531 The rack structure of the elevated deck or decks includes a set
of deck panels, or
deck panel assemblies, of which a representative one is shown in Figure 2a as
deck panel
assembly 80. Other than as noted, assembly 80 is symmetrical about the
longitudinal vertical
(i.e., x ¨ z) centerline plane of the rack, and spans the open space between
the left and right
hand side wall support structure of car 20. It may also be noted that deck
panel assembly 80
may be manufactured in different lengths, and a set of deck panels 80 is
installed to define a
full length deck of car 20, be it deck 70 or deck 72. As may be appreciated,
each of deck
panels 80 may be replaced as an individual module if damaged or corroded, or
in need of
replacement or repair for whatever reason. Deck panel assembly 80 includes a
main, or first,
decking panel 82, first and second, (or left and right) side beams or rails
84, 86, first and
second, or left and right, upper longitudinally running members 88, 90; a
vehicle placement
securement fitting, or fitting array 92, hinge fittings 94, 96, and first and
second, or left and
right hand, longitudinally extending underside stringers 100, 102.
100541 Main decking panel 82 may include a central portion 104 and left and
right hand
edge or margin portions 106, 108. Main decking panel 82 may have an upper
surface 112
which defines a roadway, or pathway, or track 114 over which wheeled vehicles
may be
conducted in the lengthwise direction (or x-direction) in the normal procedure
of loading and
unloading vehicles in autorack cars. Main decking panel 82 may also have an
underside, or
downwardly facing surface that faces toward the next lower deck, be it the
middle deck (in
the case of an upper decking panel) or the railroad car main deck 40 of
underframe 22. As
installed, main decking panel is spaced upwardly from the next lower deck by a
distance
commensurate with the carrying of another layer of vehicles on the deck
therebelow. Main
decking panel 82 may have an undulating form, with up-and-down undulations in
the vertical
direction made to increase its effective depth of section and therefore its
second moment of
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area for resistance to bending. The undulations may run cross-wise, namely in
the lateral,
transverse, left-to-right, or y-direction. The undulations run in the
direction generally cross-
wise to the lengthwise running direction of main decking panel 82 generally,
and also of
pathway 114. The undulations may have the form of corrugations 118.
[0055] Central portion 104 may be formed as a single section, or may
be formed by
welding two left and right halves together. In that context, the left and
right halves may be
identical, but reversed and welded together along a central seam. Central
portion 104 may be
formed on a curvature such that it has an arcuate crown 120, of which the
crest is at, and runs
along, the longitudinally running centerline. The downwardly and outwardly
sloped margins
or edges of central portion 104 meet, and are joined to, left and right hand
margin portions
106, 108. The junction of these components may be formed by welding. Margin
portions
106 and 108 are oriented horizontally. That is, if decking panel 82 is placed
on a flat surface,
margin portions 106 and 108 will lie in a common horizontal plane, which
central portion
104 deviates convexly arcuately away from that plane.
[0056] Side beams, or rails, 84, 86 run in the lengthwise direction
along margin portions
106, 108. Each side beam 84, 86 has a first leg 122 that extends substantially
horizontally, a
second leg 124 that extends substantially vertically, and a roll-formed lower
flange 126
which is located distant from first leg 122. In this way first leg 122
functions as an upper
flange, and second leg 124 functions as a vertical shear web. The distal
portion of first leg
122 that is most distant from second leg 124 overlaps, and is welded to, a
respective one of
margin portion 106 or 108. The corrugations of margins 106, 108 extend
downwardly of
first leg 122. The ends of portions 106, 108 terminate inboard well clear of
second leg 124,
and are offset laterally inboard relative to flange 126, such that a water
drip falling straight
down from an open corrugation end would drop clear of flange 126.
10057] Longitudinally running members 88 and 90 are mounted to the
upwardly facing
surfaces of the corrugations, symmetrically to either side of the centerline
of crown 120.
Members 88 and 90 may have the form of open structural section members, and in
one form
may be inverted channels or top-hat sections with the toes of the legs mated
to surfaces 112
of the successive corrugations. Members 88 and 90 may function as upper,
longitudinal
flanges of deck panel assembly 80. They may also function as upstanding
guideways, or
curbs, for wheeled vehicles being conducted along deck panel assembly 80. To
the extent
CA 2795654 2017-11-14
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that the open section faces downward, and is self-draining, it is not a place
where moisture,
dirt, or other material may tend to collect.
[0058] Securement fitting 92 may have the form of a locking rail
spaced laterally
outboard from member 90. Securement fittings may be placed on both sides of
the centerline
of deck panel assembly 80, however, in the embodiment shown only a single
securement
fitting rail is shown, it being a non-symmetrical feature of an otherwise
symmetrical
assembly. The apertures formed in the inboard upstanding leg of securement
fitting 92
provide engagement points for wheel lock-down apparatus, or chocks, used to
prevent
motion of wheeled vehicle lading during operation of railcar 20.
[0059] Hinge fittings 94 and 96 may mate with corresponding hinge
fitting of adjacently
placed movable decks or bridge plates, as may be. Mounting bracket assemblies
98 define
the mounting interfaces at which deck panel assembly 80 is connected to the
side post array,
and thus suspending in an overhead spanning position relative to any lower
deck or decks.
[0060] Underside stringers 100 and 102 may be mounted to the
underside, or
downwardly facing surface of the successive corrugations of main decking panel
82. They
may be placed laterally outboard of respective upper longitudinally running
members 88, 90.
They may be placed laterally closer to side beams 84, 86 than to members 88,
90. Each may
be placed adjacent to a respective slope discontinuity 128 at the junction of
central portion
104 and each of side portions 106 and 108. Underside stringers 100, 102 may
each be placed
to overlap slope discontinuity 128, thereby to provide reinforcement at what
might otherwise
be a location of weakness in the panel.
[0061] Mounting bracket assemblies 98 may include fittings such as
mounting plates
130, which may be substantially rectangular and which may define a mounting
foot of deck
panel assembly 80. They may have pre-bored holes that locate on the upright
posts, as may
be. Diagonal reinforcement, or braces, or load spreading members 132, 134 may
be
positioned with one end rooted to plate 130, and a distant end attached to
main decking panel
82 or to one of underside stringers 100, 102.
[0062] In the past, stringers for autorack decks have been made with
an L-shaped piece
of steel, and angle iron, installed with its toes upward, mounted to the
underside of the deck
sheet. When thus mounted, the stringer forms a trough that may be liable to
collect dirt and
CA 2795654 2017-11-14
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debris, particularly during the shot blast process prior to painting where the
trough may tend
to function as a shot trap. When debris or other material of this nature
remains in the trough,
it subsequently may be a rust initiation site, and may cause or hasten
premature rusting of the
rack. Further, where rusting occurs, and there is moisture in the car, whether
from collection
of rain or snow, dripping of automobiles when loaded, or from condensation
overnight, the
rusty water may drip on the automobiles carried as lading within the autorack,
thus
potentially ruining their finish. Shot that collects from the blast process,
as well as dust, dirt
and debris from ordinary usage, should be removed. It is a painstaking task.
The process
may be difficult due to either lack of access or poor access. It is generally
desirable to need
to spend less time cleaning after blast, and to deliver a cleaner product. By
replacing the L-
shaped stringer with a closed section, the trough is covered. A closed
stringer prevents shot,
dust, and dirt from being collected, greatly simplifying cleaning. This may
tend to
discourage or prevent the collection of debris therein. This in turn may
reduce or eliminate
the need for cleaning, and may reduce or delay the onset of rusting of the
stringer. Having a
closed stringer may tend to prevent it from trapping dirt, and hence to reduce
the need for
regular cleaning, or to allow longer intervals between cleaning. Having a
cleaner autorack
may tend to allow them to deliver automobiles with less dirtying and damage.
[0063] Several embodiments of a closed stringer are shown and
described herein. This
includes typical L-channels with closure plates welded either on top or
inside; a roll-formed
profile with continuously welded seam; and standard hollow structural
sections.
[0064] In Figure 3a a stringer, be it 100 or 102, is shown as 140.
Stringer 140 runs the
length of deck panel assembly 80. As may be noted stringer 140 has an external
wall section
142 that defines a periphery, that is, when oriented as installed, closed at
the top side as at
144, such that water may not tend to collect in stringer 140, and such that
blast shot may also
tend not to collect. The periphery may be closed all-around such that the
section is a closed
hollow structural section. The external wall 142 includes not only the top
side or part or
portion, but another portion 146 that forms the remainder or balance of the
closed section.
Further aiding in closing the section, stringer 140 may be closed at its ends,
as, for example,
by end caps 138 such as may be welded or otherwise fixed in place.
[0065] The closed section may have a multitude of different possible
forms. It may be
substantially circular, or square, or rectangular, or D-shaped. In the
examples shown it may
be substantially three-sided or triangular. The sides or parts, or portions
need not be planar,
i.e., linear as viewed in section. However many sides there are, and whether
those sides be
CA 2795654 2017-11-14
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straight or not, the upper part may provide a surface, or seat, such as at 148
for mating
engagement with the underside of main decking panel 82. In the embodiment
illustrated in
Figures 3a and 3b, top side 144 has a kinked or dog-legged, or gull-winged, or
reflex angle
shape, there being first and second parts 150 and 152 of top side 144, parts
150 and 152
meeting at an internal angle that exceeds 180 degrees, the angle and shape
being suited to
seat next to, to accommodate, or to conform to, the slope change, or slope
discontinuity, at
the transition or junction between central portion 110 and one or the other of
margin portions
106, 108 of main decking panel 82. Top side 144 need not be horizontal, but
may be on a
slant, such that it may not be the "top" of stringer 140, but may be the
uppermost side
thereof In the example of Figures 3a and 3b, parts 150 and 152 may be
substantially planar.
The end portions, or legs 154, 156 of parts 150 and 152 may be roll formed
such that they
curl inwardly next adjacent to each other. Where the radii of the back of legs
154, 156 come
together, a fillet weld is formed along stringer 140 as indicated at 136. The
fillet weld may
lie shy of (i.e., below), or flush with the planes of parts 150 and 152 so as
not to impede
mounting of stringer 140 next to the transition of main decking panel 82. As
can be seen, in
this embodiment top side 144 overlaps the slope change discontinuity in main
decking panel
82. In this embodiment, in which stringer 140 is substantially triangular in
section, top side
144 may be the long side, and the other two sides are identified as second
side 158 and third
side 160. Second and third sides 158 and 160 may meet at a right-angled
corner. Any or all
of the vertices of the section may be radiused, as indicated.
[0066] In other embodiments, top side 144 need not be kinked or dog-
legged, but may be
straight as viewed in section (such that top side 144 is planar), or may
follow an arc such as
may correspond to main decking panel 82 and the slope change therein. Further,
stringer 140
need not be placed at, or overlap the slope change discontinuity in main
decking panel 82, or
at the junction of the margins of portion 104 with 106 or 108 as may be.
Stringer 140 could
be placed to either side of that junction, either undergirding portion 104 or
either of portions
106 and 108.
[0067] Figures 4a, 4b, 5a, 5b, 5c, 6a, 6b, 6c and 6d all show views of the
end doors of
autorack railroad car 20. In the embodiment shown doors 28 include a left hand
door 200
and a right hand door 202. In this embodiment, each of doors 200 and 202 is a
folding door,
and, in this example, a multiply folding door. Doors 200 and 202 are
substantially the same
in terms of their major structural components, and differ only to the extent
of secondary
fittings, such as door latching hardware and so on. To that extent, a
description of the
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structure of one door may be taken as a description of the structure of the
other door,
allowing for left and right handedness.
100681 As illustrated, door 200 (or 202 as may be) may be a triple
folding, or tri-fold,
door. With terminology based upon door 200 being in the closed position of
Figure 4a,
commencing at the laterally outboard secured hinged edge 204 at which door 200
mates
hingedly with side wall 68, door 200 may include a first, or staff or outside
or laterally
outboard, member or wing or panel, 206, a second, or intermediate, or middle,
member or
wing, or panel 208, and a third, or laterally inboard, or distal, or distaff,
wing, or member or
panel 210. As may be understood, first panel 206 is hingedly connected to side
wall 68 at
hinges 212, as noted, with hinges 212 permitting rotation of panel 206 in the
clockwise
direction as seen from above; second panel 208 is hingedly connected to first
panel 206 at
hinges 214, which may have the form of upper and lower piano hinges as
illustrated. Hinges
214 permit pivotal rotation of second panel 208 in a clockwise direction
relative to first panel
206; and third panel 210 is hingedly connected to second panel 208 at hinges
216, hinges 216
permitting counter-clockwise pivotal motion of third panel 210 relative to
second panel 208.
Thus, in the fully open position shown in Figure 4b, first panel 206 has been
rotated outboard
from the 12 o'clock position to the eight o'clock position, second panel 208
has been rotated
such that its vertex at hinge 214 is adjacent the side sill, and third panel
210 is folded back
the other way to lie against second panel 208, with its free edge laterally
outboard.
100691 The door height may be relatively great, being of the order of
up to 16 ft 9 in from
the main deck level to the top center of the gable, and up to about 12 ¨ 1/2
ft at the top chord.
The width of a full door may be a maximum of 64 inches in total for three
panels to fit within
the 128 inch AAR maximum allowable clearance width, the width of the widest
panel of a
tri-fold door being up to about 30 inches wide. Further, when a bi-fold or tri-
fold door is
closed, the door may tend to stand in a y-z plane, being generally flat. This
may be
compared to a radial arm door in which the section of the door has the depth
of the
corresponding arc, and therefore stiffness corresponding to the depth of
section. The widths
of panels 206, 208 and 210 may be unequal. For example, panel 206 may be of
sufficient
width to have a ladder, or ladder rungs, 270 mounted thereon. Panel 206 may be
in the range
of 113 to 1/2 of the width of door 200. Panel 210 may be wider than panel 208.
For example,
in one embodiment panel 206 may be 22 ¨ 24 inches wide, and each of panels 208
and 210
may be about 15 ¨ 16 inches wide. When unfolded and pivoted around, panels
206, 208 and
210 lie substantially in-line in a plane (a y-z plane in this example) across
the end of the car
CA 2795654 2017-11-14
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as shown in Figure 4a. In this view, an outboard releasable securement
fitting, or latch, 218 is
mounted to outboard panel 206, and, in the closed position engages mating
fittings, shown as
dogs 220 at deck level. Dogs 220 may be mounted to the face of the end sill. A
releasable
latch 222 may be mounted to middle panel 208, to mate with lower and upper
fittings 224,
226 at the main deck and gable roof levels respectively. Lower and upper
latches 228 and
230 may be mounted to panel 210 near free edge 232 of panel 210 (and door 200
more
generally) in door 200 (or 202), by which to engage the lower and upper ends
of panel 210 to
the main deck and to the gable end, respectively.
[0070] Tri-fold doors on the ends of autoracks are typically quite large in
spanning
dimensions in the plane of the door (in the z and y directions, as closed),
and thin in through-
thickness (i.e., in the x-direction, as closed) with low stiffness in out-of-
plane bending
deflection. As can be seen, each door panel is relatively tall and quite
narrow, with an aspect
ratio of height to width of the order of 7:1 to 8:1 for the outside panel 206
and roughly 10:1
to 12:1 for third panel 210. Each panel has a skin or web, or sheet 221, and
may have
vertical reinforcements, or ribs, or stiffeners, and horizontal stiffeners.
[0071] For the panels of door 200 the large vertical length may tend
to contribute to
vibration issues. Door 200 may have a maximum vertical height or span from its
lower edge
236 at, or adjacent to, main deck 40 to its upper edge 238 at the gable end of
roof structure
66, that height being designated as L210 for panel 210. When doors 200, 202
are closed,
motion of upper and lower edges 236, 238 may be constrained by the various
latches 218,
222, 228. That is, the latches restrain displacement of the edges of the door
in the x and y
directions, but do not transmit a bending moment. The door panels, and the
door assembly as
a whole susceptible to vibration, and, in particular, to vibration in the mode
in which the pin
securements at the main deck and the pin securements at the gable roof tend to
define nodal
points of zero deflection at which x-direction displacement may be considered
to be nil.
[0072] It may be helpful to provide one or more elements that have the
effect of either (a)
defining vibration nodes intermediate the end nodes defined at roof structure
66 and at main
deck 40, such as may tend to correspond to higher mode vibration (and
therefore higher
natural frequency) and to inhibit lower mode vibration inconsistent with the
location of the
vibration nodes; or (b) tending to dampen vibration motion, whether that
motion is motion in
the lowest natural frequency mode or otherwise.
CA 2795654 2017-11-14
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100731 For either or both of those purposes, car 20 may include
dynamic response
members 240 and 242. In some embodiments dynamic response members 240 and 242
may
be referred to as bumpers or dampers. Dynamic response member 240 may be
associated
with a first nodal point location 244 relative to the vertical span of door
200 (or 202), and, in
particular, of one panel thereof, such as distal panel 210. In a hi-level car,
for example, first
nodal point location 244 may be located at a height, h244 corresponding to the
height of first
elevated deck 70. First nodal point location 244 is intermediate the nodal
points defined at
the interfaces with the main deck and roof respectively. In a hi-level car
that height may be
taken as being in the range of 2/5 to 3/5 of L210, and typically may be about
half of L210. In a
tri-level car h244 may be in the range of 3/10 to 2/5 of L210, and may
typically be about 1/3 of
L210. A tri-level car may have not only a first nodal point location 244, but
also a second
nodal point location 246. Second nodal point location 246 is also intermediate
the deck and
roof interfaces. Dynamic response member 242 may be associated with a second
nodal point
location 246 relative to the vertical span of door 200 (or 202), and, in
particular, of panel 210
thereof Second nodal point location 246 may be located at a height h2.46,
which may
correspond to the height of second elevated deck 72. In a tri-level car h246
may be in the
range of 3/5 to 7/10 of L210, and may typically be about 2/3 of L210.
[0074] Either of dynamic response members 240 or 242 may be a single,
monolithic
member mounted to door 200 (or 202), or to the end of deck 70 (or deck 72, as
may be).
Either or both of members 240 and 242 may be referred to as a bumper or as a
damper.
Alternatively, either or both of dynamic response members 240 and 242 may
include a first
member 250 and a second member 252. First member 250 may be, or may include, a
bumper
pad or damper or damper member 254. Damper member 254 may include an
elastomeric
damping element, or may be made of an elastomeric damping material. Damper
member 254
may have the form of a cylinder of damping material, such as a circular
cylindrical damper
member shown in Figure 6d, with a central bore for a fastener, counter-sunk at
one end to
accommodate passage of a mechanical fastener such as a bolt 260. The counter
sink permits
the bolt head to sit well shy of the end of the bore, and therefore distant
from the opposing
face of second member 252, such that they may tend not to contact each other
in use. Second
member 252 may define an opposed member, or a mating member against which, or
in co-
operation with which, first member 250 works. That is, in operation first
member 250 and
second member 252 may bear against each other, such that second member 252 may
be said
to define a seat which first member 250 may contact, and against which first
member 250
may work. In one embodiment first member 250 may have the form of an
elastomeric pad
CA 2795654 2017-11-14
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256 and second member 252 may have the form of a plate, or stop, or deck
reinforcement, or
abutment 258 such as may oppose bumper pad 256 and may spread relatively
evenly and
transmit, and reaction force from or into deck 70 or 72, such as may
discourage local damage
thereto. Bumper pad 256 may have a central socket or depression, or relief or
accommodation, or countersink 262, such as may accommodate the head of a
fastener such
as a bolt 260 by which, for example bumper pad 256 may be secured to panel 210
(or 208, or
206) of door 200 (or 202, as may be). In one embodiment first member 250 is
mounted to
door 200, and second member 252 may be mounted to deck 70 or 72, as may be.
Alternatively, second member 252 may be mounted to door 200, and first member
250 may
be mounted to deck 70 or 72. To the extent that the decks of the rack
structure may be
defined as a stationary datum, or stator, for the purposes of vibration, the
member mounted to
the door, which is presumed to be the moving member in vibration, may also be
termed the
moving or dynamic member.
[0075] It may be that the engagement or co-operation of first member 250
and second
member 252 may be one-way limiting. That is, in terms of the degree-of-freedom
of
displacement in the x-direction, mutual interaction of first member 250 with
second member
252 may limit motion of panel 210 of door 200 in the +x direction toward deck
70 (or 72, as
may be), but may not impede, inhibit, or obstruct motion of panel 210 of door
200 in the ¨x
direction away from deck 70 (or 72).
[0076] In one embodiment, either or both of dynamic response members
240 and 242
may divide, or break-up, the vertical span of panel 210 into lesser fractions
such as may tend
to correspond to a higher mode, or higher frequency, of vibration in the
lengthwise direction.
Alternatively, or additionally, either or both of members 240, and 242 may
serve to dampen
such vibration as may occur.
[0077] In one embodiment, pad 256 may be mounted to door panel 210,
and may have an
axial adjustment member, be it a shim, or set of shims, or a threaded member
such as a bolt
260, to permit adjustment in the x-direction. Equally, it may be the position
of abutment 258
that may be adjusted by the use of shims or a threaded member. Such adjustment
may be
locked in place once set, e.g., with locknuts or wire. In either case, the
axial i.e., x-direction,
relationship of pad 256 and abutment 258 may be set such that as door 200 is
closed, pad 256
is positioned just to touch the end face of abutment 258 with contact but zero
pre-load. In
another embodiment the relationship may be adjusted such that when door 200 is
closed pad
CA 2795654 2017-11-14
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256 is compressed either by a predetermined distance of compression, be it
1/16 or 1/8 of an
inch or some other distance, such as within a clearance range of 0 inches, +0
to -1/8, or by a
predetermined loading, be it 5 lb or 10 lb of pressure, or such pressure as
may be.
[0078] Generally, there is a panel member that is large in its extent in
the vertical
direction, and also substantial in its extent in the lateral direction as
compared with the panel
thickness. The panel is hingedly attached to an adjacent panel of the door.
The panel has
first and second, spaced apart nodal points at which it is, in the closed
position, secured,
attached, or tethered, those two nodal or attachment locations being typically
at the top and
bottom ends of the panel next adjacent to the main deck floor and to the roof
respectively. A
third element is introduced intermediate the first and second nodal points or
attachments to
break up the span. In the embodiments shown in the illustrations and described
above, that
third, or intermediate, element may be a damper in the form of a bumper pad.
[0079] By adding dynamic response members, or bumpers, longitudinal inward
motion in
the door may be inhibited if not entirely stopped. This may help to interrupt
the span of the
vibrating member and may tend effectively to raise the natural frequency, such
that the doors
may be more resistant to motion and subsequent damage from vibration.
Alternatively
motion damping may tend to convert kinetic energy of mechanical motion to
heat. This
feature may make the tri-fold doors more resistant to vibration, and therefore
less susceptible
to vibration-induced fatigue damage. By being less susceptible to damage from
vibration,
operators may require less effort to maintain the doors.
[0080] Dynamic response members 240 and 242 are intended to be
representative. A
greater number of dynamic response elements could be incorporated. Bumpers may
be
added at one or more locations on the interior of door 200 (or 202) and on any
of panels 206,
208 and 210, or at the decks or sides of the autorack. They could be made of
any material,
though softer ones like rubber would more effectively dissipate the
vibrational energy.
[0081] As noted above, outboard door panel 206 may have an access or step
assembly in
the nature of a ladder 270. In one embodiment ladder 270 may have, or may be,
a series of
ladder rungs 272, mounted to door panel 206. When door 200 (or 202) is closed,
rungs 272
are hidden, facing inwardly into the inside of car 20. When door 200 is open,
and latched in
the open position as shown in Figure 4b, one may climb up rungs 272 to ascend
any of the
decks, as may be. Co-operating hand-hold rungs 268 are provided inside housing
26. Ladder
CA 2795654 2017-11-14
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270 may include, at its lowermost end a footstep, or sill step, or lowermost
foothold member
or assembly, indicated as 280, described in greater detail below. It may be
noted
preliminarily that car 20 also has another step assembly, in the form of
another ladder, or set
of ladder rungs, 274 mounted in a fixed position on the outside wall of
housing 26 near the
"point", or corner, of car 20, with a lowermost foothold, or step 276
depending from the side
sill. This ladder may be used by railroad personnel while operating the
adjacent handbrake
apparatus 278, also mounted to the outside of housing 26, longitudinally
inboard of ladder
rungs 274. It is not intended that ladder 270 be confused with ladder 274.
[0082] Lowermost foothold assembly 280 is a movable sill step, or foothold,
as seen in
the progression of views in Figures 7a, 7b, and 7c. In the embodiment shown
foothold
assembly 280 includes is a stationary portion (i.e., in fixed position
relative to the door
panel, be it 206) in the form of co-operative first and second mounting
brackets, indicated as
left hand bracket 282 and right hand bracket 284. These brackets are mounted
in fixed
position on door 200, and vary only in handedness. The foothold assembly, or
step, or rung
assembly 280 also includes a movable portion, which, in one embodiment has the
form of a
generally U-shaped step 286, and an axle or cross-piece 288. U-shaped step 286
has left and
right hand arms 290, and a rung, 292. Cross-piece 288 also defines the first
hand-rung (or
second foot rung) of ladder 274. U-shaped step 286 is movable relative to door
200 between
the retracted, transition, and deployed positions shown in the Figures. When
brackets 282,
284 are installed, they form a yoke that captures cross-piece 288 (and thus
all of the movable
portion of assembly 280). The term "capture" means that although the movable
portion can
move, it is constrained throughout its entire operating envelope to stay
mounted to the yoke.
It cannot escape, i.e., come loose and fall off the car.
[0083] Each of brackets 282, 284 has a first portion in the nature of
a base or foot or
fitting 294 that mounts to door 200, such as to the inside face thereof, e.g.,
on panel 206; and
an outwardly standing second portion, which may have the form of a wing or
flange, or lug,
or yoke end, or seat, 296. The movable portion of assembly 280 includes mating
members
that lodge in seats 296 of brackets 282, 284. It may be noted that cross-piece
288 has ends
that are not round in section, but rather that have been flattened to
rectangular tabs 298.
Those tabs define mating members that have the form of "keys" or protrusions,
or wings,
which, in the embodiment illustrated may have a generally rectangular cross-
section.
CA 2795654 2017-11-14
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[0084] Scat 296 includes an indexing member or fitting in the form of
an accommodation
300 that mates in co-operable inter-engagement with a mating indexing feature
302 of the
movable portion of assembly 280, such as a respective one of tabs 298.
Accommodation 300
may have the general form, or shape, of a keyhole, as illustrated.
Accommodation 300 has a
first portion 304 and a second portion 306. First portion 304, which may
correspond to the
leg of the keyhole shape, may define a pocket, or solid-bottomed slot, or
hold, or seat, that
permits a single degree-of-freedom of motion, in this instance vertical
translation. Notably it
does not permit a rotational degree-of-freedom about the horizontal axis of
cross-piece 288.
In the embodiment shown, as installed, second portion 306 is above first
portion 304.
Second portion 306 may have a generally round, circular shape such as to
permit motion of
the keys in a different degree-of-freedom, such as rotation of tabs 298,
whereby the
orientation of the moving portion of the assembly may be changed. The
rectangular tabs 298
function as the indexing members, or keys, that are able to seat in first
portion 304 in a
limited number of distinct positions. In the embodiment shown there are two
such positions,
namely the first, or 12 o'clock, position shown in Figure 7a, and the second,
or 6 o'clock
position shown in Figure 7c. In this embodiment the positions shown are
reversible, i.e., one
is the inverse of the other. The effective angle of rotation of tabs 298 is
180 degrees.
However, a key with legs angled as some angle other than 180 degrees could be
formed, as
might be appropriate. When in either position the movable portion of assembly
280 is
constrained to sit in a predominantly upright or upwardly vertical or
predominantly
downwardly depending or downwardly vertical position, and is prevented from
moving to an
out-of-plane position or orientation, (as by rotation about the axis of cross-
piece 288) by the
engagement of the sides of the keys in the mating slot. Transition between the
first and
second positions requires un-seating tabs 298 from first portion 304 by
lifting step 286, i.e.,
in the vertical translational degree-of-freedom. Once in second portion 306,
step 286 is then
swung in a different degree-of-freedom, e.g., rotation, either upward or
downward as may be
appropriate, to the other position. Finally, now-reversed tabs 298 are again
introduced into
first portion 304 by translation in the degree-of-freedom dictated by the
direction of the slot,
where step 286 is again inhibited from rotating or otherwise moving in the out-
of-plane
direction. In the upward, or stowed, or retracted or inoperative position
shown in Figure 7a,
door 200 may be closed. In the deployed position of Figure 7c, a person may
climb ladder
270, but door 200 may not be closed. It may be noted that in the embodiment
shown
assembly 280 if free of springs. It is also free of loose parts that might be
lost.
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[0085] The position shown in Figure 7a is a local equilibrium
position. The position
shown in Figure 7b is a global equilibrium position. In each instance,
potential energy must
be added to the system to move it from an equilibrium position in the slot of
first portion 304
to the transition position or condition of second portion 306. If the step is
left in a non-
equilibrium position, gravity will urge it to a local or global lowest
potential energy state into
one or other of the positions in which rotation is inhibited.
[0086] Accommodation 300 and mating indexing feature 302 are inter-
engaging female
and male parts. This relationship is to some extent arbitrary, since, a
different configuration
or embodiment could be made in which the accommodation is formed on the moving
part,
and the mating lug or key is formed on the stationary part.
[0087] Conventionally, door steps are mounted to the side of the car
and fixed in place.
The design of the car is such that a conventional door step mounted on the
door would
impede the door closure. The retractable step allows an operator to climb onto
the car like a
normal door step (when extended), hut also allows the doors to be closed (when
retracted).
When in the stowed position, the step is tucked next adjacent to the door
panel, at a height
above, and clear of, the main deck such that the door may close. In the
extended position the
step depends below the height of the main deck, with the foot rung 292 being
at a comparable
level of height to that of depending step 276. As well, the movable door step
described may
tend to be relatively easy to manufacture and use, and may tend to be robust.
The design is
self-contained. The operator will only need to move the step from one position
to the other.
[0088] The retractable door step as described allows for positive
locking in both the
operational position, and the stored position. The design also allows for the
step to be moved
from one position to the other without any additional parts, or parts that
have to be retracted
and replaced, such as a pin or key, that may otherwise be lost, or not re-
positioned correctly.
This is accomplished by the design of the first handhold on the step (included
in door step
assembly). This handhold interacts with brackets on the door that contain a
key slot cut-out.
By moving the door step, the handhold moves around in the key slot, and is
able to lock in
the operation position, or the stored position.
[0089] One known car requires a locking mechanism to hold the step in
place when
stored. The embodiment shown eliminates this part and consequently eliminates
an operation
that a worker will need to perform when using the car. This may tend to yield
simplicity and
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ease of use of the door step for the operators. Reduction in use of extra
parts may end to
reduce maintenance. A known design uses a door step that slides vertically up
or down. A
catch lock at the top provides locking in the stored position. The embodiment
shown
eliminates the use of a catch lock, and instead uses a key slot and the door
step weight, i.e.,
gravity, to provide the locking.
100901 Various embodiments have been described in detail. Since changes
in and or
additions to the above-described examples may be made without departing from
the nature,
spirit or scope of the invention, the invention is not to be limited to those
details.
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