Note: Descriptions are shown in the official language in which they were submitted.
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AIR RETURN BULKHEAD FOR REFRIGERATION TRAILERS
This application is a continuation-in-part of application serial number
08/701,215, now abandoned.
BACKGROUND OF TH~ ~NTION
S A refri~eration bullihead is a passive device mounted on the inside front
wall of a refrioeration trailer. It generally covers the width of the front wall and
has a hei~ht either halfway up or fully covering the front wall, thereby covering all
or part of a refrigeration unit uenerally mounted at the upper center portion of the
wall. The bulkhead serves two functions. First, it creates a space between the
10 trailer load and the trailer front wall. This space is used to facilitate air movement
from the floor of the trailer up the front wall to the refri~eration unit. Through its
air intake, the refriYeration unit can remove heat from the air and exhaust the heat
to the outside of the trailer. Second, the bulkhead protects the refrigeration unit
from fork lifts or other loadin~ devices and their loads.
15 BRIEF DESCRIPTION OF THE PRIOR ART
Refrigeration trailer bulkheads are well known. The earliest bulkhead was
a wooden pallet arran(~ed on end to protect the refri~eration unit while still
providing air flow. The temporary pallet was then replaced with a more permanentand aesthetically pleasing lattice work assembly of alnmin~lm uprights and
20 crossmembers. While these prior bulkheads afforded protection to the refriYeration
unit, they did not provide directional air flow throu(~hout the trailer resultinY in
short cycling, i.e., uneven temperature distribution within the trailer.
As the need for directional airflow within the trailer was recoYnized, solid
bulkheads replaced lattice work structures. Essentially? the cross members of the
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lattice were replaced by solid sheets of plywood, fiberglass reinforced plyw-ood, or
thin oau~e aluminum. The bulkhead eYtended between the sides of the trailer and
was sealed at the top. with the bottom being left open for a return air intake
Most recently, molded polyethylene bulkheads have been introduced as
5 solid bulkheads. These are strong enough to resist impact and include several
vertically arran~ed ribs which direct air throu_h the space between the bulkheadand the trailer front wall. At the bottom of each rib is a small triangular shaped
opening for air intake. Other air intake holes are located on the side of the vertical
ribs. While the prior molded bulkheads are inexpensive, easy to install in a variety
10 of trailers, and stackable, they do not fully overcome the short cyclin_ problem
referenced above because they do not provide adequate directional and cross-
directional return air flow to the refrigeration unit. Furthermore, they do not
accommodate expansion and contraction due to fluctuating temperatures.
SUMMARY OF THE IN~/~NTION
Accordingly, it is a primary object of the invention to provide an air retum
bulkhead adapted for mounting adjacent a refri_eration unit in spaced relation from
a front vertical wall of a refrigeration trailer. The bulkhead includes a rectangular
panel molded from synthetic plastic material and includin_ a front wall and sidetop, and bottom walls e.Ytending nommal to the front wall to define a cavity The20 front wall includes a plurality of horizontally spaced tapered sections in the lower
portion thereof which define a plurality of pallet stops co-planar with the front
wall. The tapered sections e~ch contain a plurality of openin_s which enable air to
enter the cavitv from the bottom of the trailer. First and second baffles eYtend into
the cavity from the rear of the front wall. The first baffles are arran_ed above the
25 tapered sections and the second baffles are on opposite sides of the rear upper
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portion of the front wall. The baffles reinforce the panel and cooperate to direct air
upwardly and toward the center of the cavity where the refrigeration unit is
arran_ed.
According to another object of the invention. the first baffles are arranged
5 at an angle relative to a horizontal line and extend upwardly toward a vertical
centerline of the panel. The first and second baffles each contain at least one recess
enabling air to pass therethrough.
It is a more specific object of the invention to provide a plurality of integralflanges extending from the top, bottom and side walls generally parallel to the front
10 wall. The flanges can be trimmed in order to fit the panel within trailers ofdifferent dimensions. An improved mechanism for fastening the bulkhead to the
trailer wall via the flanges is also provided
BRIEF DESCRIPTION OF THE FIGURES
Other objects and advantages of the invention will become apparent from a
15 study of the following specification when viewed in the light of the accompanying
drawing, in which:
Fig. 1 is a cutawav perspective view of a refrigeration trailer illustrating theoptimum air flow therethrough;
Fig. 2 and 3 are perspective views, respectively, of refrigeration trailer
20 bulkheads according to the prior art;
Figs. 4 and 5 are front plan and perspective views. respectively, of the air
~ return bulkhead according to the invention;
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Fig. 6 7, and 8 are sectional vie- s taken along lines 6-6, 7-7, and 8-8,
respectively of Fig. 4.
Fjg g is a front plan view of a preferred ~mbodiment of the air return
bulkhead of the invention:
FigT. 10 is a rear perspective vie w of the bulkhead of Fig. 9;
Fi~J. 1 1 is a front plan view of the panel flan(Jes illustrating the fastenin~
assembly therefor; and
Fi~. 12 and I ~ are front and top plan views, respectively, of a washer used
for the fastening assemblv of Fig. 11.
DETAILED DESCR~PTIO~
The field of the invention will first be described with reference to Fi~. 1
wherein a refrigeration trailer 2 is shown. These trailers are used to transportnumerous refri~erated products includin~ ice cream~ produce. meat, computers,
15 and dry goods. Accordingly, thev include a refrigeration unit 4 which is mounted
on the front wall 6 of the trailer toward the top and center thereof. The
refrigeration unit cools air within the trailer. e~hausts heat to the e~cterior of the
trailer, and distributes the cooled air into and through the trailer. As shown by the
arrows 8, internal return air ideally is drawn into the refrigeration unit at the
20 bottom front of the trailer and distributed adjacent the top w all 10 of the trailer
toward the rear. The cool air falls to the floor at the rear and along the sides of the
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trailer where it is drawn back to the refrigeration unit.
In order to protect the refrigeration unit from the load and from forklifts
used to load the trailer and to afford air flow to the refrigeration unit, bulkheads
were developed for the front wall of the trailer. In Fi_. 2, there is shown a lattice
S work bulkhead comprisin~ vertical aluminum z-bars 12 and aluminum cross bars
14. In addition to being labor intensive to install, lattice type bulkheads do not
provide directional return air flow to the refrigeration unit within the trailerresulting in short cyclin_ and hot and cold spots within the trailer rather than a
desirable uniform temperature.
In order to improve air flow, a solid bulkhead was developed as shown in
Fig. 3. This bulkhead retained the vertical aluminum columns 12 but replaced thecross members with sheets of plywood l 6 which in some instances included
fiberglass for reinforcement. An apertured screen 18 is arran_ed along the bottom
of the bulkhead and serves as an air inlet. Pallet stops 20 at the bottom of the15 columns 12 are provided to prevent dama_e to the bulkhead and the refri Jeration
unit. Aithough an improvement over the lattice type bulkheads, the solid fiber_lass
reinforced plywood bulkhead of Fig. 3 is expensive and heavy making it difficult to
install and requiring custom fitting for each size trailer.
Turning now to Fi_s. 4-8, the air return buikhead accordin to the
20 invention will be described. The bulkhead is essentially a unitary panel 22 which is
molded from synthetic plastic material into a generally rectangular configuration.
As well be developed below, the panel can be formed with a standard width and
height and then trimmed to fit refrigeration units of different configurations.
Preferably, the width of the panel is such that the panel extends generally across the
25 width of the trailer front wall. The height of the panel is at least half the height of
the front wall and preferably selected so that the panel extends over at least the air
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return of the refrigeration unit. The panel is adapted for mountin(J within the trailer
adjacent to but spaced from the front wall to define an air return space between the
panel and the trailer wall. No support members are required.
The panel 2~ inc~udes a front wall 24, a top wall 26? a bottom wall 28, and
5 side walls 30. The top. bottom7 and side walls e~tend in a direction normal to the
planar front wall to define a cavity for air flow. Along the bottom, the panel front
wall includes a plurality of spaced tapered sections 32. As shown in Fig. 6, thetaper e~tends downwardly and rearwardly at an angle oc relative to the plane
cont~ining the front wall. The angle ~ is on the order of 30~. Each tapered
10 section contains a plurality of openings 34 which allow air to be drawn into the
cavity. The openings are preferably arranged in rows and columns, with the same
number of openings being provided in each section so that air is drawn into the
cavity uniformly from across the bottom of the panel The tapered sections
containing the openings further act as a filter to prevent debris from entering the
1 5 cavity.
Between the tapered sections 32 the remanin_ portions of the front wall
define bumpers or pallet stops 36 a_ainst which a pallet bearing a load can be
placed within the trailer.
A plurality of first baffles 38 are integrally molded within the panel front
20 wall 24. More particularly, the baffles e~tend into the cavity from the rear surface
of the front wall. Each baffle has a sinusoidal configuration as shown in Fig. 7 to
define recesses 40 through which air may pass. As shown in Fig. 4, the first baffles
~ are arranged in two sets on opposite sides of the panel. Each of the baffles e~tends
upwardly toward the vertical centerline at an angle ~ reiative to horizontal The25 an_le ~ is preferably 60C.
A pair of second curved baffles 42 are provided adjacent the upper portions
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of the side walls 30. The second baffles are also inte~Jrally molded with the panel
and e~tend from the rear surface thereof with a sinsusoidal confiouration to define
a plurality of recesses 44.
The first baffles 38 direct air from the openinos 34 upwardly and toward
the center of the panel where the refrigeration unit is located. The second baffles
42 direct air laterally toward the upper central portion of the panel. Thus, thebaffles cooperate to circulate air toward the refrigeration unit. The recesses in the
baffles afford cross-ventilation and equalize the pressure and air flow within the
cavity. These two features improve air movement and result in increased efficiency
of the refrigeration unit which receives air from the bulkhead and exhausts warmair to the outside of the trailer and cooled air to the interior of the trailer adjacent
the top wall as shown in Fig. 1. Moreover, the sinusoidal configuration of the
baffles reinforce the panel since the portions between the recesses can abut aoainst
the front wall of the trailer.
I j The top 26, bottom 28, and side 30 walls of the panel each include a flanoe
46 e~tending therefrom in a direction parallel to the front wall. The flange can be
trimmed to adapt the panel to di~lelllly sized trailers, so that once installed. such
as by screwing the panel to the walls of the trailer. a sealed bulkhead is provided,
but for the openings 34 alono the bottom thereof.
A preferred embodiment of the invention is illustrated in Figs. 9 and 10. As
- is evident from these figures, the rect~no~ r panel 122 is similar to that of the
embodiment of Fi~os. 4-6 and includes a front wall 124, a top wall 126, a bottomwall 128, and side walls 130 which define an air flow cavity. The front wall
includes spaced tapered sections 132 cont~ining openings 134 and definino palletstops 136. A flan~e 146 e~tends from the top, bottom, and side walls.
.
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The primary difference in the embodiment of Fj(JS. 9 and 10 from that of
Figs. 4-6 is in the configuration of the first baffles 138 and the second baffles 142.
As best shown in Fig. 9, the lower portion of the baffles 138 are aligned with the
pallet stops 136. This arrangement improves the air flow of the bull;head since air
entering the cavity via the openings 134 in the tapered sections 132 passes
upwardly and between the baffles 138. The outermost baffles 138a are truncated
to allow a space between these baffles and the side walls 130. The second baffles
142 extend parallel to the vertical centerline CL of the panel. The first and second
baffles 138 and 142 contain at least one recess 144 as shown in Fig. 10 to allow the
10 passage of air therethrougrh.
The bulkhead of Figs. 9 and 10 also includes a truncated third baffle 148
co-linear with the vertical centerline CL which is also aligned with a central pallet
stop 136. Where the upper portions ofthe first baffles on opposite sides ofthe
centerline intersect, the first baffles have a portion 150 of reduced dimension as
15 shown in Fig. 10. This enables air to flow throu_h the intersecting baffles at the
center of the bulkhead.
Another difference in tlle bulkhead of Figs. 9 and 10 is the provision of a rib
152 extending laterallv across the front panel 124 between the upper ed~es ofthepallet stops 136 and the lower portions of the first and third baffles 138. 148. The
20 rib, which ma~rr also be provided in the bulkhead of Figs. 4-6. increases the rigidity
and strength of the bull;head.
One drawback to screwing the panels to the trailer wall is that the panels
buckle or separate from the wall owing to expansion or contraction of the plastic
material in response to temperature fluctuations. This deformation of the panels25 destroys the seal around the perimeter of the panel. whereby air flow behind the
bulkhead is no longer controlled in the proper fashion.
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In order to overcome this problem, an improved fastening system for the
bulkhead is provided ~~hich allows for limited movement of the bulkhead relative to
the trailer wall. Referring to Fig. 11, the flange 146 extending from the top,
bottom? and side walls contains a plurality of slots 154 in the outer edge thereof. A
5 washer 156 is arranged within and above each slo~ and is adapted to receive a self-
tapping screw or rivet 158. Referring to Figs. 12 and 13, the washer 156 includes
an oblong upper portion 156a and a depending shoulder portion 156b through
which a rivet-receiving opening 160 passes. The shoulder portion 156b of the
washer has a depth greater than the thickness of the flange and an outer diameter
less than the width of slow 154. The top oblong portion 156a has a long
dimension greater than the width of the slot. Because of the unique configuration
of the washer, the bulkhead panel 122 is afforded a limited degree of movement
relative to the wall to which it is fastened to accommodate expansion and
contraction thereof.
While in accordance with the provisions of the patent statute the preferred
forms and embodiments of the invention have been illustrated and described it will
be apparent to those of ordinary skill in the art that various changes and
modifications may be made withiout deviating from the inventive concepts set forth
above.
