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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to an arrangement for securing
bulkhead doors employed in the compartmenting of cargo or bulk lading in a
freight transport vehicle such as a railway freight car, a freight
trailer, or the like. More particularly, the present invention relates to
an improved locking arrangement for a bulkhead door in a railroad freight
boxcar known as Palletized Shipping Program (PSP) freight car in which
adjustably movable bulkhead doors are adapted to be locked in place
relative to cargo or lading so as to prevent subsequent movement and
damage thereto.
Palletized Shipping Program (PSP) railroad boxcars are frequently utilized
in the shipment of bulk commodities, such as grain, cereals, and other
types of comestibles. In view thereof, these vehicular carriers tend to be
considered as mobile warehouses, and governmental regulations require that
the carriers be of a design enabling the grain and other food products to
be shipped in a clean and sanitary manner meeting prerequisite standards.
Accordingly, a transport vehicle of this type should make provision to
allow for the removal and cleaning of grains and other foodstuff residues
which may serve as a harborage and breeding grounds for insects, vermin,
and other pests commonly associated with food products of this nature. The
transport, vehicle must be periodically cleaned or disinfected, and areas,
such as hidden locations not readily accessible and which are susceptible
to infestation, must be able to be effectively treated with insecticides.
In prior art Palletized Shipping Program boxcars, the locking mechanisms
for the movable bulkhead doors have generally been of two commonly
employed designs.
2. Discussion of the Prior Art
In accordance with one prior art design, the bulkhead doors, usually two
per vehicle or railroad boxcar, are locked into position against loaded
cargo through the use of vertically extending lever-operated pins mounted
in the doors which engage holes in bulkhead locking tracks located in and
extending along each longitudinal side of the vehicle floor. A typical PSP
boxcar is fifty feet in length and, in accordance with this prior art
bulkhead locking arrangement, approximately 250 locking holes are formed
in each locking track on each side of the boxcar, in effect, a total of
about 500 holes for each boxcar. Each track includes a channel member
having the locking holes spaced along its length and with the interior of
the channel member being preferably filled with urethane foam to minimize
cleaning and contamination problems with the track. In accordance with
this approach, if a bulkhead door is to be locked in place using a
particular set of locking holes, the urethane foam in those holes is
removed, such as by drilling, to permit insertion of the door locking
pins. With continued usage of the boxcar, those holes having the urethane
foam removed therefrom cause cleaning and resultant infestation problems.
Another problem associated with this prior art approach is that the
urethane foam presents an additional infestation problem in that insects
and insect eggs tend to invade inner spaces where the foam meets surfaces
of the floor plate or in cracks which occur in the foam. In view thereof,
each track must be periodically completely stripped of its urethane foam,
possibly several times each year, and then refoamed. An operation of this
nature requires a partial disassembly of the PSP boxcar to obtain access
to an open end of the track. The inside of the track is then blasted, as
with a sandblasting technique, to remove the old contaminated urethane
foam therefrom. Each track must be subsequently refilled with new urethane
foam, and the transport vehicle reassembled; obviously a relatively
time-consuming and expensive operation, particularly considering that each
transport vehicle is not available for its primary purpose of transporting
goods during this lengthy and cumbersome servicing operation.
In accordance with a second prior art design for PSP boxcar bulkhead door
locking tracks, a recessed track having a series of raised pins is
positioned so as to extend along each longitudinal side of the transport
vehicle. A movable bulkhead door is then selectively positioned over
appropriate raised pins on each side of the vehicle, thereby locking the
door in place. Although each recessed track together with its series of
pins is easier to clean than a vehicle constructed in accordance with the
first approach employing urethane foam-filled tracks, the open tracks
generally must extend the full length of the transport vehicle on each
longitudinal side thereof, and the recessed areas tend to collect and trap
residue such as grain and collected floor dirt, forming regions subject to
insect infestation. It would be desirable to have an arrangement for
locking bulkhead doors which is easily cleaned, as by vacuuming, and which
may be effectively and easily treated with a minimum and safe application
of insecticides.
Another disadvantage encountered in the prior art arrangements is that a
damaged track must be repaired in a railroad service yard, with the
attendant drawback that the vehicle is not available for freight
transportation during the time interval required to effect the necessary
repairs.
Brown, Jr., et al. U.S. Pat. No. Re. 27,615 discloses an arrangement for
protecting lading or freight in a transport car in which the freight is
secured in place by movable bulkhead doors. In this arrangement the
bulkhead doors are provided with latching studs which cooperate with
depressions in fixed members at the top and bottom of the car to secure
the door in place against the cargo. Furthermore, the bulkhead doors are
provided with inflatable cushions which may be expanded against the cargo
to further assist in securing it relative to the transport vehicle.
Vander Hyde, et al U.S. Pat. No. 3,168,055 discloses an arrangement in
which railroad cars are equipped with rigid bulkhead doors movably
positioned on overhead tracks and latching at their top and bottom to lock
the doors in place against the cargo. In this prior art arrangement, upper
and lower latching pins project from the bulkhead door into latching
openings formed periodically along the length of the track members to
secure the door in place.
SUMMARY OF THE INVENTION
Accordingly, in order to eliminate or ameliorate the disadvantages
encountered in the prior art, the present invention contemplates the
provision of a locking arrangement for bulkhead doors in a transport
vehicle in which the number of separate securing apertures or holes
provided in the vehicle is substantially reduced, with a consequent
reduction in the amount of time and effort required to clean the vehicle
and treat it with insecticide. In one specific embodiment of the invention
disclosed herein, only twenty-two holes are provided along both locking
tracks on each side of the vehicle, which results in a substantial
reduction in the amount of time and related costs to clean and treat the
holes with insecticides (particularly considering that up to 500 holes or
100 feet of open track are provided in existing prior art arrangements).
It is a specific object of the present invention to provide a locking
arrangement for bulkhead doors which does not require periodic refoaming
of a track with its attendant disadvantages as described hereinabove.
Another object of the present invention is the provision of an arrangement
of the type described wherein the potential for infestation by insects and
other pests is greatly reduced, thereby also substantially reducing the
danger of spoilage as a result of the infestation of grains and other food
products shipped in the transport vehicle.
Yet another object of the present invention is to provide a locking
arrangement for bulkhead doors in transport vehicles wherein damage to the
door securing equipment may be easily repaired without the removal of the
transport vehicle to a railroad service yard and from active service
during the effectuation of repairs.
A further object of the present invention lies in the provision of an
arrangement of the type described which may be installed in new railroad
boxcars or retrofitted to existing PSP boxcars at a minimal cost.
More specifically, the present invention contemplates the provision of an
improved locking arrangement for a bulkhead door in a freight transport
vehicle, such as a railroad boxcar, in which at least one locking track
extends along a portion of the longitudinal length of the vehicle at each
side thereof and includes a plurality of engaging apertures or holes
therein formed periodically along its length. A locking plate having
several securing posts extending downwardly therefrom at a spacing
complementary to that between the engaging holes on the locking track is
adapted to be mounted on the track whereby the plate may be adjustably
positioned at selective locations along the length of the locking track.
The locking plate has additional locking holes formed therethrough and
spaced along its length with the number of locking holes formed therein
per unit length being substantially greater than the number of engaging
holes per unit length in the locking track, thereby providing a large
plurality of locking or engaging holes per unit length in the locking
plate through which a bulkhead door may be secured to the locking track of
the transport vehicle.
Additionally, the bulkhead door includes a securing means mounted along its
edge which is complementary to the engaging means on the locking plate so
that they may be secured relative to each other to thereby fixedly
position the bulkhead door in the freight transport vehicle. Pursuant to a
preferred embodiment, the securing means for the bulkhead door includes a
longitudinally extensible vertical locking pin which is adapted to engage
at its lower end in one of the spaced apertures in the locking plate.
Moreover, in accordance with the teachings set forth herein, the novel and
inventive locking arrangement is designed for particular use in a railroad
boxcar of the PSP type. Generally, each transport vehicle is equipped with
two locking tracks, one each positioned along each longitudinal side
thereof, and at least one locking plate is provided for each track. The
locking track extends along a substantial portion of the length of the
vehicle, but preferably not for the full length thereof, and is centrally
positioned relative to the opposite end of the vehicle. Furthermore, in
accordance with a preferred embodiment, each locking track comprises an
elongated, rectangularly-shaped steel plate constructed so as to be set
into the transport vehicle with the upper surface flush with its floor
level, the locking plate being mounted thereon and elevated relative to
the vehicle floor.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects and advantages of a novel bulkhead door
locking arrangement which is constructed pursuant to the present invention
may be more readily understood by one skilled in the art, reference being
made to the following detailed description of preferred embodiments
thereof, taken in conjunction with the accompanying drawings wherein like
reference numerals are utilized to refer to similar elements throughout
the several views; and in which:
FIG. 1 is a schematic plan view of one prior art locking arrangement for
bulkhead doors;
FIG. 2 is an enlarged, partially sectional view of a segment of a prior art
bulkhead door locking track used in the arrangement of FIG. 1;
FIG. 3 illustrates a plan view of one preferred embodiment of a bulkhead
door locking arrangement constructed pursuant to the present invention;
FIG. 4 is an enlarged sectional view taken along line 4--4 in FIG. 3,
illustrating further details of the locking track;
FIG. 5 is an enlarged sectional view taken along line 5--5 in FIG. 3
illustrating details of construction of a locking plate mounted on the
locking track and with a locking pin in a bulkhead door engaging an
aperture formed in the locking plate;
FIG. 6 illustrates a plan view of one embodiment of a locking plate
constructed pursuant to the present invention;
FIG. 7 and 8 illustrate, respectively, side and end views of the locking
plate shown in FIG. 6, with FIG. 8 being in an enlarged scale;
FIG. 9 is an enlarged sectional view taken along line 9--9 in FIG. 6,
showing further details of construction of the locking plate; and
FIGS. 10 and 11 are, respectively, plan and elevational fragmentary views
showing the fastening of the bulkhead door to the locking plate and
locking track.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now in detail to FIG. 1, there is shown a schematic plan view of
a prior art arrangement for locking a bulkhead door 10 in a boxcar 12 of
the Palletized Shipping Program (PSP) type. In this arrangement the
bulkhead door is locked into position against loaded cargo by the use of
vertically-slidable lever-operated pins (not shown) mounted in the door
which selectively engage holes 14 in bulkhead tracks 16 which are located
in the floor extending along each side of the boxcar. A typical PSP boxcar
is 50 feet in length, and in one standard arrangement approximately 250
locking holes 14 are provided in each track 16 extending along each side
of the boxcar 12. As illustrated in further detail in FIG. 2, each track
16 includes a flat, rectangularly-shaped steel plate 18 having a large
number of vertically-extending holes 14 formed therein and spaced along
its length, the top surface of the plate 18 being normally coplanar with
the floor of the boxcar. The bottom portion of the track 16 is formed by a
channel member 20 having a U-shape in cross-section, which is fastened to
the plate member 18 by a plurality of welds 22 extending along the length
of the track structure. The interior of each channel member and the holes
14 may be filled with a suitable dense urethane foam 24 to minimize
cleaning and contamination problems with the track. If a particular
locking hole, such as hole 26, is to be utilized to secure a bulkhead door
in place, the urethane foam in that hole is removed, as by drilling. With
continued usage of the boxcar, additional holes 28 will also have urethane
foam removed therefrom, thereby resulting in greater cleaning and
infestation problems with the track.
FIG. 3 illustrates a plan view of one preferred embodiment of a bulkhead
door securing arrangement in which bulkhead door locking tracks 30 extend
along the length, and at each side, of a freight transport vehicle 12,
such as a boxcar. Each track includes a plurality of engaging means, in
the form of vertically-extending holes or apertures 32, spaced along the
length thereof. In accordance with one preferred embodiment, each track is
a rectangularly-shaped plate installed in the floor of the boxcar with the
upper surface being flush with the floor, is 20 feet long, and contains
eleven 21/4 inch diameter engaging holes 32 formed therein spaced along
the length of the track. The floor 34 beneath each vertically-extending
hole 32 is also bored with a 21/4 inch diameter hole, as illustrated in
FIG. 4, so as to form an extension of each hole 32. Each locking track 30
is secured periodically along its length by a section of hollow pipe or a
solid post 36, illustrated in FIG. 11, which is welded at 38 to the bottom
of the track member, and extends through the boxcar floor 34 to the boxcar
chassis 40, to which it is also suitably secured as by a weld 42 to
thereby form a permanent solidly anchored structure.
The arrangement described thus far provides a securing arrangement for a
bulkhead door locking plate 44 which is of a relatively short length in
comparison to the locking track 30 and has several short cylindrical posts
46 extending downwardly therefrom spaced for cooperative engagement with
the holes 32 in the locking track 30. The vertically-extending posts 46
provide a securing means for the locking plate 44 which is complementary
to the locking holes 32 in tracks 30 such that, for example, three
vertically-extending cylindrical posts 46 may be selectively engaged in
three adjacent locking holes 32 in track 30. The locking plate 44 has a
plurality of bulkhead door engaging means in the form of
vertically-extending, elongated holes 48 formed to be spaced periodically
along its length, with the number of holes 48 per unit length in the
locking plate being substantially larger than the number of holes 32 per
unit length in the locking track 30. The overall arrangement is such that
the considerably larger number of engaging holes in locking plate 44
provides for a greater number of engaging means per unit length to which a
bulkhead door may be secured. FIG. 6 graphically illustrates that for the
three engaging apertures spaced along the length of track 30, locking
plate 44 provides for eighteen holes 48 spaced along its length. In
accordance with the present disclosure, each bulkhead door 12 may be
constructed pursuant to concepts well known in the state of the art, and
includes vertically-extensible rods or pins 50 adapted to engage locking
holes 48.
Each locking plate 44 is constructed of a rectangularly-shaped, flat plate
52 to which the vertically-extending posts 46 are attached, such as by
suitable welds 54. Downwardly depending and outwardly tapered side skirts
56 extend longitudinally along each side of the plate 52 and may be formed
integrally therewith, as by pressing or stamping from a flat steel plate.
Tapered end plates 58 are provided at each end of the plate 52, and may
also be formed integrally therewith. The tapered side and end plates 56
and 58 provide a suitable slope or ramp leading to the plate 52 over which
freight may be moved and freighthandling machinery, such as forklifts, may
travel without tipping. Each of the four corners 60 of the locking plate
44 may be suitably shaped to eliminate sharp edges therefrom. All of the
components described thus far, including the locking tracks 30 and the
various components of each locking plate 44 may be constructed of a
suitable steel.
In a retrofitting application of the structure of the present invention to
existing bulkhead doors, the locking pins 50 in each bulkhead door may be
shortened by approximately one inch, as the pins need no longer extend
through the floor surface. In a typical retrofitting operation, no other
modifications to the bulkhead doors would be necessary, unless the doors
have less than a two-inch clearance to the floor, in which case the doors
must be correspondingly shortened. In retrofitting the equipment described
herein for use in existing PSP boxcars, the old door tracks in the floor,
as illustrated in FIG. 1 hereof, must be removed, new flooring installed,
and the new bulkhead door locking tracks mounted in the new floor.
In accordance with the present invention, it is sufficient to provide a
total of twenty-two locking holes or apertures each having a diameter of
21/4 inches, eleven holes in each track 30, along both sides of a railway
boxcar. The result of this is to provide for fewer and larger (and
therefore more easily cleanable) locking holes in the overall securing
arrangement in contrast with the prior art.
As illustrated in FIG. 3, in most instances the door tracks 30 need not
extend the full length of the boxcar 12, but instead need extend within
the vehicle at which there is a substantial probability of a need for the
positioning of a bulkhead door.
In usage or operation of the equipment described thus far, a transport
vehicle is loaded except for the final two stacks in each end by the
doorway. The locking plates are then placed in locking holes in the
locking tracks approximately two feet from the ends of the previously
loaded freight. The final stacks are then loaded, the bulkheads are placed
in position against the freight, and the locking pins secured in the holes
in the locking plate. Locking plates may also be used to secure bulkheads
in place in empty, in-transit boxcars to prevent door movement and
resultant damage thereto.
The present invention has been described with respect to a locking track
having a plurality of engaging means in the form of locking apertures
formed periodically therein. In an alternative embodiment, the locking
track may be provided with other suitable engaging means, as for instance
suitable pins extending therefrom, in which case the complementary
securing means on the locking plates would be suitably spaced apertures.
Likewise, the locking arrangement between the locking plate and bulkhead
door may also take other suitable forms other than those described in
detail herein. The locking tracks may also be constructed with a fewer or
greater number of locking holes, and may be of various lengths with
respect to the vehicle. Also, in some arrangements, the bulkhead doors may
be split vertically so as to constitute two side-by-side half doors, in
which case two additional longitudinally-extending locking tracks may be
constructed near the center of the vehicle to accommodate for the split
arrangement of the bulkhead doors.
While several embodiments and variations of the present invention have been
described in detail herein, it will be apparent that the teachings of the
present invention will encompass many other structures within the purview
of one of ordinary skill in the art.
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