U.S. patent application number 09/752387 was filed with the patent office on 2002-07-04 for mechanized fumigation tent.
This patent application is currently assigned to Western Industries, Inc.. Invention is credited to Langhart, Chris.
Application Number | 20020083970 09/752387 |
Document ID | / |
Family ID | 25026115 |
Filed Date | 2002-07-04 |
United States Patent
Application |
20020083970 |
Kind Code |
A1 |
Langhart, Chris |
July 4, 2002 |
Mechanized fumigation tent
Abstract
The present invention provides a fumigation tent which includes
a frame suspended from a structure by support cables, the frame
having an underside; a tarp adapted to be mounted to the top side
of the frame, the tarp hanging from the frame defining a tent
having a top and side curtains having a lower periphery that
defines a bottom perimeter; a sealing arrangement for connecting
and sealing the top of the tarp to the frame; a first plurality of
cables for raising and lowering the side curtains and being
connected to the side curtains and to means for raising and
lowering the first plurality of cables; a second plurality of
cables for raising and lowering the frame and being connected to
the frame and to means for raising and lowering the second
plurality of cables.
Inventors: |
Langhart, Chris; (New Hope,
PA) |
Correspondence
Address: |
KENNETH P. GLYNN, ESQ.
24 Mine Street
Flemington
NJ
08822-1598
US
|
Assignee: |
Western Industries, Inc.
|
Family ID: |
25026115 |
Appl. No.: |
09/752387 |
Filed: |
December 29, 2000 |
Current U.S.
Class: |
135/115 ;
135/905; 160/19; 422/28; 422/292; 422/294; 422/306; 422/32; 422/33;
426/320; 426/331; 426/333; 426/335 |
Current CPC
Class: |
E04H 15/18 20130101;
A23L 3/34095 20130101; A23L 3/3409 20130101; Y10S 135/905 20130101;
A61L 2/20 20130101 |
Class at
Publication: |
135/115 ; 422/28;
422/32; 422/33; 422/292; 422/294; 422/306; 135/905; 426/320;
426/331; 426/333; 426/335; 160/19 |
International
Class: |
E04H 015/54; B01J
007/00; A23C 001/00; A23B 004/00; A23K 001/00; E06B 009/00; A01N
001/00; A61L 002/00; A61L 009/00; E04H 015/00; A23L 001/36; A23C
003/00; A23L 003/36; A21D 004/00; E04H 015/32 |
Claims
What is claimed is:
1. A mechanized fumigation tent for being suspended from an
overhead structure, and for being raised and lowered relative to
said overhead structure, which comprises: (a.) an overhead
structure; (b.) a support frame having a top; (c.) a tarp mounted
atop said frame and hanging from said frame to define a top and
side curtains, said curtains having a lower periphery which defines
a bottom perimeter; (d.) a first plurality of cables, being curtain
cables, and communicating with said overhead structure and being
functionally connected to said side curtains and adapted for
raising and lowering said side curtains relative to said support
frame; (e.) a second plurality of cables, being frame cables, and
communicating with said overhead structure and being functionally
connected to said frame and adapted to raise and lower said frame
and tarp relative to said overhead structure; (f.) mechanized cable
moving means for moving said front plurality of cables and said
second plurality of cables so as to raise and lower said curtains
by raising and lowering said first plurality of cables, and so as
to raise and lower said frame and tarp by raising and lowering said
second set of cables.
2. The mechanized fumigation tent of claim 1 wherein tent further
includes: (g.) means for sealing said bottom perimeter of said side
curtains.
3. The mechanized fumigation tent of claim 2 wherein said means for
sealing is a flexible base mounted along said bottom perimeter for
viewing, holding and releasing water from an external water supply,
whereby when holding water, will seal said tent to a floor.
4. The mechanized fumigation tent of claim 1 wherein said
mechanized cable moving means is at least one winch.
5. The mechanized fumigation tent of claim 1 wherein said first
plurality of cables and said second plurality of cables are each
connected to at least one clew, which are in turn functionally
connected to said mechanized cable moving means.
6. The mechanized fumigation tent of claim 4 wherein said first
plurality of cables and said second plurality of cables are each
connected to at least one clew, which are in turn connected to said
at least one winch.
7. The mechanized fumigation tent of claim 1 wherein said second
plurality of cables is connected to said support frame by an
attachment arrangement which penetrates said tarp top.
8. The mechanized fumigation tent of claim 7 wherein said
attachment arrangement includes tarp top sealing means to prevent
fumigation gases from exiting said tent.
9. The mechanized fumigation tent of claim 8 wherein said
attachment arrangement is a removable attachment arrangement which
includes a plate, a threaded rod, a compressed foam, a compression
plate and a nut tightened onto said frame and tarp to establish a
seal.
10. The mechanized fumigation tent of claim 1 wherein said support
structure is formed of a triangular cross-sectional shape.
11. The mechanized fumigation tent of claim 1 wherein said first
plurality of cables is connected to a first clew and said second
plurality of cables is connected to a second clew, said first clew
is connected to said mechanized cable moving means and said first
clew is functionally connected to said second clew whereby said
first clew may be moved a first distance to raise said side
curtains and may also be moved an additional distance to
functionally simultaneously move said second clew therewith to
effect raising of said support structure and tarp.
12. The mechanized fumigation tent of claim 11 wherein said
mechanized cable moving means in at least one winch.
13. The mechanized fumigation tent of claim 11 wherein said first
clew and said second clew are mounted on at least two common
guidewires attached to said overhead structure and wherein said
second clew is positioned between said first clew and said
mechanized cable moving means.
14. The mechanized fumigation tent of claim 12 wherein said first
clew and said second clew are mounted on at least two common
guidewires attached to said overhead structure and wherein said
second clew is positioned between said first clew and said
mechanized cable moving means.
15. The mechanized fumigation tent of claim 11 wherein said tent
further includes: (g.) means for sealing said bottom perimeter of
said side curtains.
16. The mechanized fumigation tent of claim 15 wherein said means
for sealing is a flexible hose mounted along said bottom perimeter
for viewing, holding and releasing water from an external water
supply, whereby when holding water, will seal said tent to a
floor.
17. The mechanized fumigation tent of claim 11 wherein said second
plurality of cables is connected to said support frame by an
attachment arrangement which penetrates said tarp top.
18. The mechanized fumigation tent of claim 17 wherein said
attachment arrangement includes tarp top sealing means to prevent
fumigation gases from exiting said tent.
19. The mechanized fumigation tent of claim 11 wherein said
attachment arrangement is a removable attachment arrangement which
includes a plate, a threaded rod, a compressed foam, a compression
plate and a nut tightened onto said frame and tarp to establish a
seal.
20. The mechanized fumigation tent of claim 11 wherein said support
structure is formed of a triangular cross-sectional shape.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a mechanized tent. In
particular, it relates to a mechanized tent having a frame and a
collectable tarp attached to the frame which can be raised and
lowered over pallets of produce or the like, particularly useful
for fumigation of produce, e.g. imported products.
[0003] 2. Information Disclosure Statement
[0004] Once fumigated, produce has a shelf life of at most ten days
to two weeks. It is therefore desirable to fumigate the produce
close to the place where it will be ultimately sold. For imported
produce, this place is typically inside a dock building or
warehouse located at a port of entry. Pallets of the produce are
unloaded from a ship and placed or staged on the floor of the dock
building.
[0005] Known methods of fumigating produce involve covering the
pallets of produce with a polyethylene or plastic impregnated
tarpaulin and then introducing a gas, e.g., methyl bromide, under
the tarp to kill live insect infestations. Workers climb on top of
the pallets or use poles to pull the tarp over a group of pallets.
Because it is necessary for the gas to circulate freely on all
sides and the top of the pallets, the tarp cannot lay flat on the
top of the pallets. The United States Department of Agriculture
requires that a space of about two feet be provided on the top of
the pallets, and at least two feet on their sides to allow room for
the placement of fans to facilitate the circulation of the
fumigation gas. The fans may be tied down with rope to prevent them
from moving. Several hoses for introducing the gas is secured to
the top of selected fans. The volume of space under the tarp, i.e.,
the total cubic feet, determines how many fans and points of
introduction are required.
[0006] One method for maintaining the required space on the top of
the pallets is to erect wood frames in the shape of a "T" or an "A"
at each corner and attach rope between each "T" or an "A" to create
a web of support for the tarp. The side space is maintained by
draping the tarp outward as it contacts the floor of the dock
building and securing it in that position by placing flexible vinyl
tubes (approximately 6" in diameter and 4' long) filled with sand
on top of the edge of the tarp. At least 2 feet of excess tarp
remains beyond the `sand tubes`.
[0007] The steps involved in pulling the tarp over the pallets,
setting up the fans, attaching the introduction hoses to the fans,
handling hundreds of tubes of sand, and dismantling and storing all
of the above equipment, and repeating the process upon completion,
require many labor intensive hours.
[0008] Improvements to the conventional method of fumigating
produce include permanently suspending the tarpaulin from an
overhead frame and lowering the frame over the pallets as needed.
Such a frame may be made from welded trusses to form a
disassemblable one piece unit of varying dimensions. The typical
frame size may be 50 feet long by 250 feet wide, but may be larger
or smaller depending upon the spacing between support columns in
the dock building. To the underside of the frame a tarpaulin is
attached which has been manufactured with grammets, i.e., tabs and
eyelets, specific to the frame it hangs from.
[0009] The frame may be raised and lowered by a system of cables
and pulleys located above the unit which are attached to exposed
barjoists on the underside of the roof of the dock building. The
cables are connected to hand-operated or motor-operated winchs
mounted on the support columns in the dock building. Workers
simultaneously crank the winches to lower or raise the frame to a
height above the pallets that allows the required 2 feet of space
between the tarp and pallets of produce.
[0010] A typical tent may be lifted by twelve or more active pickup
points. Between each of these points two counterweight sandbags are
deployed to offset the self-weight of the frame and the
polyethylene enclosure. Each truss section of the frame spans
approximately fifty feet with two midpoint sandbags. These tend to
become hung up from friction and pull at an angle to prevent the
sandbag from lowering onto the polyethylene enclosure as it is
elevated.
[0011] A difficult and time-consuming job associated with operating
such a system is gathering up the tarp which overhangs from the
sides of the frame before the frame is raised. This is necessary
because the typical dock building height of about twenty-two feet
is limited to about eighteen feet by overhead piping, electrical
conduits, etc. When the support frame is raised to the maximum
height permitted by these obstructions the tarp hangs down low
enough to catch the tops of forklift trucks as they move the
pallets of produce in and out of the tent area.
[0012] One known way of gathering up the tarp on the sides is to
run horizontal plastic pipes through double-thickness portions of
the tent walls which form pockets. These pockets can be located at
approximately one-third and two-thirds of the wall height and are
tied up to the top framing with rope every ten feet or so. Pulled
ropes raise the pockets and thus gather the sides of the tent. This
method is also time-consuming, however, because it requires
numerous tie-up procedures in order to completely raise the tent,
e.g., usually at ten to twenty foot intervals around the tent
perimeter.
[0013] U.S. Pat. No. 5,641,463 utilizes many of the aforementioned
improved technique features and additionally incorporates unique
features which are more fully discussed in conjunction with some of
the drawings described below.
[0014] Notwithstanding the above prior art, there is no teaching
which anticipates or renders the present invention obvious. Thus,
it is neither taught nor suggested to use a system with a
ceiling-mounted suspended frame with a fumigation tarp position
atop the support frame in a sealed fashion. Likewise, the prior art
is deficient in teachings related to cooperating clews or other
present invention features, as more fully developed below.
SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to provide a large
mechanized fumigation tent which incorporates the height of the
supporting frame within the tarp structure to eliminate the extra
space otherwise needed when the support structure is stacked above
the gathered, stored tarp.
[0016] It is another object of the present invention to decrease
the total weight needed for an efficiently operated fumigation
tent.
[0017] It is also an object of the present invention to provide a
fumigation tent which does not require permanent water storage
tanks, related plumbing or the otherwise necessary space which
would be occupied by permanent water storage facilities.
[0018] It is yet another object of the present invention to provide
a large fumigation tent for fumigating produce, logs, textiles,
wood products, and other forms of potentially infested imports
which can be quickly, conveniently and freely raised and lowered
over pallets of the produce.
[0019] It is also an object of the present invention to provide a
fumigation tent that does not interfere with the operation of
forklift trucks as they move pallets of the produce in and out of a
tent area and that does not require extensive tie-up procedures to
accomplish this.
[0020] Another object of the present invention is to provide a
fumigation tent which can be raised from a single remote location
so that personnel need not be near the tent area after fumigation
is complete since exposure to residual gas, which may not have been
evacuated from some pallet areas, is possible and can be
harmful.
[0021] It is yet another object of the present invention to provide
for alternative mechanisms for first lifting side curtains of the
tarp and then lifting the entire structure and, conversely,
lowering the entire structure and then the side curtains of the
tarp.
[0022] A further object of the present invention to provide a
system which seals the tent to the floor of the dock building and
which can be easily raised with tent.
[0023] The present invention provides a fumigation tent which
includes a frame suspended from a structure by support cables, the
frame having an underside; a tarp adapted to be mounted to the top
side of the frame, the tarp hanging from the frame defining a tent
having a top and side curtains having a lower periphery that
defines a bottom perimeter; means for connecting and sealing the
top of the tarp to the frame; a first plurality of cables for
raising and lowering the side curtains and being connected to the
side curtains and to means for raising and lowering the first
plurality of cables; a second plurality of cables for raising and
lowering the frame and being connected to the frame and to means
for raising and lowering the second plurality of cables.
[0024] The present invention also provides a system for sealing a
bottom perimeter of a lower periphery of side curtains of a tent to
a floor, which includes at least one flexible hose mounted along
the bottom perimeter for attachment to an external water
supply.
[0025] The present invention further provides for attachment of the
winch cables to clew plates-which in turn are attached to winches
by winch chains. There is at least one master clew for harmonizing
the movement of the first plurality of cables and at least one
curtain clew for harmonizing the movement of the second plurality
of cables. Preferably, the winches are motorized and can be
operated by remote control. (This provides an important safety
advantage, because personnel do not have to be near the tent while
it is being raised. Therefore, personnel can avoid being exposed to
any lingering fumigation gas which is hazardous.) It is also
preferable that hand winches with cables be located near the
motorized winches, so that they can be attached to the clew plates
to provide emergency back up in case electrical problems occur.
[0026] Other advantages and characteristics of the present
invention will become apparent in view of the description and
accompanying drawings that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a cross-sectional schematic view of a fumigation
tent in its lowered position from prior art U.S. Pat. No.
5,641,463;
[0028] FIG. 2 is a partial side-sectional view of the frame of the
tent in FIG. 1 as it is attached to the top portion of the prior
art tent;
[0029] FIG. 3 is a top planar perspective view of the frame and the
cables used to support the top middle portion of the prior art tent
shown above;
[0030] FIG. 4 is a partial perspective view of a side curtain of
the prior art tent shown above, with the horizontal bars and rings
which are used to support and collect the side curtain while it is
being raised;
[0031] FIG. 5 is a side perspective view of a portion of the above
described prior art tent from U.S. Pat. No. 5,641,463 in its raised
position;
[0032] FIG. 6 shows the prior art fumigation tent described above
in its lowered positioned, a water supply and removal system,
circulation and exhaust fans with their associated wiring, and
components of the gas supply system;
[0033] FIG. 7a shows a partial, cut, oblique view and
[0034] FIG. 7b shows a broken perspective view, of one embodiment
of the present invention mechanized fumigation tent;
[0035] FIG. 8 shows a partial, cut side view of details of the
sealing and suspending system for the frame and tarp shown in FIG.
7;
[0036] FIG. 9 shows details of the clew arrangement which can be
used in the present invention; and,
[0037] FIG. 10 shows a water delivery system for filling bottom
periphery flexible hosing with water for sealing curtain bottom
areas.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0038] Referring to the prior art drawings from U.S. Pat. No.
5,641,463 to the present invention herein, shown in the present as
FIGS. 1 through 5, the following description is a summary thereof:
In FIG. 1, a prior art apparatus for fumigating pallets of produce
is indicated generally as apparatus 10. It has a support system for
uniformly raising and lowering a tarp enclosure with motorized
crank winches while maintaining required clearances, as well as for
relocation of frame support cables to vertical positions above the
lifting position.
[0039] The apparatus 10 includes a frame 12 and a tarp 14 mounted
to the frame underside with tabs 24 and eye rings 25. FIG. 2 shows
detail of the top 16 being mounted. The tarp 14 forms a tent with
flat top 16, and side curtains 18 having a lower periphery bottom
perimeter 20. The frame 12 can be constructed out of aluminum pipes
welded and bolted together in a truss-like configuration. However,
as will be recognized by those skilled in the art, the frame can be
of any shape and construction which is capable of carrying the
weight of the tent. The frame 12 may be, for example, suspended
from the roof of a dock building or warehouse by support cables
22.
[0040] The cables 26 hang between cross bars 28, spaced so that
sagging of the top 16 is reduced, usually about every fifteen feet,
along cross-sections of the frame 12, as shown in FIG. 3.
[0041] Horizontal pipes 30 are fitted into tarp pockets 32 formed
in double-thickness portions of the side curtains 18, as shown in
FIG. 4, located just above the bottom perimeter 20; approximately
one-third of the distance between the first interval and the top
16; and approximately two-thirds of the distance between the first
interval and the top 16.
[0042] Winch cables 34 draw up the horizontal pipes 30. These
cables pass through rings 36 attached along and at the ends of the
horizontal pipes, as shown in FIG. 4. The tarp pockets 32 are
gathered up by the pipes 30, and support the tarp 14 as the
horizontal pipes are being raised. Each winch cable 34 passes
through a pair of guide tubes 38 and 40 fixed to a plate 42 mounted
on the frame 12, also shown in FIG. 4. Guide tubes 38 and 40 and
plate 42 provide a means for enabling the frame to be lifted by the
winch cables 34 once the horizontal pipes 30 are raised and the
tarp is completely collected.
[0043] The winch cables 34 pass around roof-mounted pulleys 44 and
around pulleys 46 mounted to support columns 48 in the dock
building, as shown in FIG. 1. They are attached at their other ends
to clew plates 50. Each clew plate 50 can accommodate up to seven
or eight winch cables 34, and is attached by a winch chain 52 to a
winch 54, as shown in FIG. 1. Winches 54, draw down the clew plates
50 with the winch chains 52, enabling each approximately fifty foot
section of the frame 12 to be lifted at twelve or more points. Some
of these points are shared with other sections along trusses 28 as
required, as shown in FIG. 3.
[0044] In the operation of this prior art embodiment, the
fumigation tent shown in the aforesaid Figures is raised by reeling
in the clew plates 50 with the winches 54, such that the side
curtains 18 are drawn upward by winch cables 34 via pulleys 44 and
46. As the winch cables 34 are drawn upward the horizontal pipes 30
on the first interval rise upward. This causes the rings 36 around
the winch cables 34 between the first and second intervals of pipes
to gather together, thus supporting and collecting intermediate
portions of the side curtains 18, and thus preventing the side
curtains 18 from "bagging out", i.e., overhanging, to half the
height of the side walls of the tent. The rings 36, horizontal
pipes 30, and pockets 32 distribute this bagout into several
smaller bagouts located between the rings that surround the winch
cables 34, so that the overhang created when the tarp 14 is
completely gathered up is minimized, as shown in FIG. 5.
[0045] Once the first interval of horizontal pipes 30 is drawn up
to the height of the second interval, the rings between the second
and third intervals gather together supporting and collecting the
intermediate portions of the side curtains 18. This process
continues until all the horizontal pipes 30 and rings 36 are drawn
up against the underside 12' of the frame 12. Once the side
curtains 18 have been completely raised, and the tarp 14 collected,
the winches 54 continue to draw up the winch cables 34, thus
raising the frame 12. The winch cables 34 are drawn up until the
frame 12 reaches a height which will enable forklift trucks to
remove the pallets of produce without interfering with the
fumigation tent. From the height where the side curtains 18 are
completely gathered up to the height the frame 12 is finally raised
to, the support cables 22, dead-tied to the roof of the dock
building, become limp, i.e., in this interval the frame 12 is
supported by the winch cables 34, as shown in FIG. 5.
[0046] This prior art fumigation tent is lowered by similar moves
for raising the tent described above, except reversing the
procedure by reversing the winches, etc. to have the cables,
pulleys, etc. operate in the opposite paths as described.
[0047] Mounting fans 56 and associated wiring 58 on frame 12 is
shown in FIG. 6. Entrance hoses 60 for supplying a fumigation gas
are positioned near designated fan locations to insure dispersion
by mixing concentrated heated gas into the accelerated airstream
provided by fans 56. A portion of these hoses rise with the tent,
requiring couplings to be made with gas heaters 61 when the tent is
lowered. A fumigation gas tank 63, which rests on a beam balance
scale 65, supplies the fumigation gas to the heater 61.
[0048] Once the tent is in place over the pallets of produce, it
must be sealed to the floor of the dock building to create a
substantially airtight enclosure, and thus prevent fumigation gas
from escaping into the dock building during the fumigation
process.
[0049] In the disclosed prior art, the method of sealing the tent
to the dock floor, is to mount a flexible hose 62 along the bottom
perimeter 20 of the tent and fill the hose with water, as shown in
FIGS. 4 and 6. The weight of the water secures the tent to the
floor of the dock building. The water can be reused by storing it
in elevated tanks 64 located above the tent, preferably mounted to
the roof of the dock building, as shown in FIG. 6. Collapsible
flexible hoses 66 supply water from the elevated storage tanks 64
to the flexible perimeter hose 62. One-way foot valves 68 connected
to the collapsible flexible hoses are employed to control columns
of water to start the Venturi acceleration process for evacuation
of the water from the perimeter hose 62. The foot valves 68 are
by-passed by solenoid valves 70 to permit gravity filling of the
hose. A compressor 72 supplies air pressure to the tops of the
elevated storage tanks 64 to assist in the gravity filling of the
flexible perimeter hose 62. Upon returning the water to the tanks,
the compressor 72 blows the water from the hose 62 toward the foot
valve location where it is carried up by the Venturi.
[0050] A water removal system is provided for evacuating the water
from the flexible perimeter hose 62 comprising jet pumps 74 located
above the tent, preferably mounted to the roof of the dock
building, using low-mounted Venturi units which shoot the water up
the collapsible flexible hoses 66 into the elevated storage tanks
64. Four distributed storage tanks limit the spilled water to
one-quarter of the system's capacity. The compressor 72 can also
supply air pressure through the collapsible flexible hoses 66 to
assist in evacuating the water from the flexible perimeter hose 62,
so that sections of the flexible perimeter hose do not collapse and
trap water, thus preventing total water removal.
[0051] Once the fumigation process is complete, the fumigation gas
is removed by exhaust fans 76 positioned on the floor of the dock
building. These fans 76 are used to evacuate the interior of the
fumigation tent before the tent is raised. Openings 78 in the tent
re-introduce fresh air, as shown in FIG. 6. After approximately two
hours of aeration, the tent is raised. It then takes approximately
one additional hour for the fumigation gas to disperse to the level
where dock personnel can enter the tent area safely.
[0052] The foregoing detailed description of the prior art
preferred fumigation tent system has many advantages, and the
overall concepts therein are incorporated into the present
invention. However, numerous disadvantages are also inherent in the
above prior art tent systems. These include:
[0053] extra space needed overhead to store stacked the support
frame above the gathered tarp. In some warehouses, dock buildings,
etc. there isn't enough clearance to use this prior art system;
[0054] costs and space involved in overhead water supply tanks and
storage lines;
[0055] time and manpower needed to install, operate and maintain
overhead water storage;
[0056] side curtains taking the weight of the side piping;
[0057] side curtains being directly in the chain of upward forces
used to lift the main frame, piping and hoses;
[0058] inability to support inside fumigation/inspection lines when
the support frame is on the outside.
[0059] Other disadvantages have been observed.
[0060] The present invention, thus, utilizes the conceptual aspects
of the prior art system, such as in house ceiling suspension,
winch/cable raising and lowering, and water hose bottom periphery
sealing. However, in its unique features, the present invention
overcomes all of the forgoing prior art shortcomings.
[0061] As will be recognized by those skilled in the art, the
present invention is not limited to fumigating produce. It can be
used to fumigate any article or object that can be placed under the
tent. Furthermore, it is contemplated that the present invention
can be adapted to be transportable.
[0062] Prior art teaches a contiguous impermeable membrane
composing the top and sides of the fumigation enclosure hung under
the support frame. So as not to be punctured by the support cables,
the prior tarp included many support loops allowing the top of the
tarp to be supported from the underside of the frame. The prior art
top loop supports and the side pipe pockets once employed,
approximately double the fabrication cost of the tarp.
[0063] Preferred in the present invention, the tarp is attached
over the frame. This is an easier installation with the frame
resting on the floor than working overhead as before. Further, with
the tarp over the support frame, overall thickness of the top of
the unit is reduced by almost half because of the inevitable
sagging of the tarp top (roof) section is within the height of the
support truss in the present invention, rather than below it as in
the prior art. In the present invention, the entire system
including the tarp are support truss assembly thickness may occupy
only about one foot in height.
[0064] Previous systems employed custom made flat frames for the
perimeter support composed of 2 in. and 21/2 in. aluminum pipe. To
better resist eccentric forces around the perimeter and
perpendicular bending horizontal loads, these frames have been
replaced in preferred embodiments with residential commodity
antenna truss. The triangle truss sections are about half of the
depth of the previous frames, stiffer due to the preferred
triangular constriction and about half of cost. Reduced tube
diameter and wall thickness of the truss reduce weight over the
previous system allowing lifting with fewer winch units.
[0065] FIG. 7a and 7b illustrate one embodiment of the present
invention, which system illustrated has several virtues over the
previous art. (FIG. 7a shows a single oblique view and FIG. 7b
shows a broken perspective view with identical parts identically
numbered and hereinafter referred to collectively as FIG. 7). two
of the major advantages are that the system will raise the frame to
the ceiling height without disconnecting or replacing with shorter
lines, the dead hang low trim frame support cables; a very labor
intensive activity. (In the prior art system, raising to and
lowering from the ceiling was done periodically to get the prior
art frame high enough to accommodate other cargo positioned below,
when not in fruit fumigation season). Secondly, the clew system and
associated guide and load cables are positioned horizontally
eliminating the need for vertical space above the winch equal to or
greater than the distance the tent sides must be raised
(eliminating the previously required space for the clew to
travel).
[0066] Thus, FIG. 7 illustrates an oblique view of a partial cut
representation an architectural situation providing structural
support as in a dock building interior. Columns 201 provide support
for a winch mounting platform and winch 202. Above are cross-arms
with holes 215, 214, and 207 permitting attachment of sheaves to
permit cords and cables to be variously directed. These cross-arms
also support the guide cables that keep the clews from twisting and
insure their cooperating operation. Above are roof support bar
joists permitting attachment of sheaves 209.
[0067] The action of the winch is to first raise the side curtains
304 of the tent up to the level of the support frame. Then further
winch operation will raise the entire frame, with side curtains 304
in the raised position, on up toward the underside of the ceiling
bar joist's underside. The winch 202 pulls the chain 204 down. This
is translated to a horizontal pull by sheave 203. Chain 204 pulls
clew 205 which is vertically supported by guide cables 208. The
clew allows one cable to pull many cables such as examplary cable
206 shown in solid lines. The pull on cords 206 is translated into
various directions by the sheaves mounted on cross-arm 207. These
cords variously arrive at sheaves mounted to the underside of the
several roof support bar joists 209. From these sheaves the cords
drop down to touch the floor and then return part way up to the
support truss frame where they are attached (dead tied). As these
cords 206 pass down to the floor they pass under the bottom edge of
the tarp 303 toward the inside of the side skirt. The length of the
cords 206 as they reach back up to the support truss are adjusted
before being dead tied such that the bottom of the side skirt will
reach the floor and yet can be gathered tight to the support truss
301 when raised. When so raised, clew 205 pushes into clew 212 as
the chain 204 is shortened by the winch pulling. Clew 212 remains
`part way` out on the support cables 208 by reason of the weight of
the support frame 301 pulling down on cables 213 (dashed lines).
The `part way` distance is maintained by dead tie cable 211 which
is anchored to the left column 201. This distance controls the
height that the frame 301 is above the top of the stacks of fruit
or other product. The frame is attached to the cable 213 by the
FIG. 8 assembly 302 described below in more detail, which allows
the tarp 303 to be sealed when over the frame 301 yet permitting
the support. When the frame is raised to the ceiling for off season
storage, cable 211 goes slack because clew 212 is pushed leftward
by clew 205 as the chain 204 is taken up by winch 202. To insure
reliable operation, weight box 221 pulls the two clews away from
one another to overcome occasional friction of the clews when in
close proximity on guide cables 208. Cable 222 connects the two
clews and passes around a sheave or sheaves atop the weight box
221. With the sheave support, the vertical travel of the weight is
minimized as the clews move.
[0068] FIG. 8 shows a perspective view of one embodiment of the
details of a present invention cable support and seal unit. Support
cable 213 is shown and this is the same as cable 213 of FIG. 7.
These cables are, for example, spaced approximately at 15 foot
intervals around the perimeter. The shackle or quick-link 102
allows fast cable detachment for service. Orifice 104 is for
shackle attachment is established on thread rod 106. The lower end
of the thread rod 106 is attached to base plate 112. Nut 105
compresses stiff plate 107 spreading out the area of force area
against closed cell foam 108. The compressed foam area seals the
plasticized tarp material against baseplate 112 of assembly 100.
After the sections of the truss are connected, assemblies such as
assembly 100 of FIGS. 8a and 8b are placed periodically around the
perimeter. The tarp 109, fabricated with sides attached, is placed
over the truss frame section 110. At the installation location, a
small hole is punched in the tarp top to allow passage of the
thread rod and eye of assembly 100. A gas tight seal is formed by
tightening the nut 105 and compressing the plate 107, foam 108, and
the tarp 109 against the base plate 112 of the FIGS. 8a and 8b
assembly 100.
[0069] FIG. 9 illustrates a perspective view of details of a
sequential clew arrangement which may function in a fashion similar
to the clews of FIG. 7, organized in a circular grouping. Here,
guide wire 901 carries two clews, curtain clew 920 and master clew
910 (referred to as master clew because it is connected to the
cables connected to the support frame.)
[0070] Curtain clew 920 contains a pipe section 922, having guide
wire 912 pass therethrough, and a disc section 924. Disc section
924 is connected to curtain cables 931, 932, 933, 934 and 935. When
curtain clew 920 is pulled to the left by cable 950 and the
attached winch, it advances a distance before it contacts and moves
clew 910. During this traverse, it raises curtains to a fully
pulled up position. When it travels further, it moves along clew
910 to raise up the entire support structure similar to clew 212 of
FIG. 7. Clew 910 is connected to support structure (frame) cables
902, 903, 904, 905 and 906. When lowering (unwinding) the winch for
the clews to move left to right, restraint chain 916 stops the
lowering of the frame at the desired height above the produce or
other items to be fumigated. A counterweight may be included (not
shown) to assure the continued movement of clew 920 away from clew
910 for complete lowering of the curtains.
[0071] With respect to the present invention, a plurality of clew
arrangements would be utilized with coordinated or computer
controlled coordination of plural winch operation, or a plurality
of sequential clews and a small number of winches could be
utilized.
[0072] FIG. 10 shows sample external water supply mechanism. Here,
it is a portable, mobile system which includes a water tank and
pump truck. Often multiple tents are not used simultaneously and
the previous system of having tanks and pumping equipment dedicated
to each tent has been improved by providing a portable pumping and
water supply system usable at various tent locations. This saves
costs and installation and maintenance manpower. This portable
apparatus functions substantially as the previous system described
in prior art except that the water is delivered from a separate,
external source and the pump pressures may be reduced as the lift
head is less and the foot valves and venturi nozzles would not be
required. Initial investment is reduced for each tent as the result
of shared facilities. Perimeter hose 305 of FIG. 7, when the tent
sides are fully extended downward, rests on the dock building
floor. To prevent water ponding, and in the winter icing, the floor
of the dock is typically sloped toward the sea, e.g., approximately
18 inches downward for every 100 foot measured perpendicular to the
sea-wall. This floor condition requires that water truck connection
to be located at the lowest point on the perimeter of the hose 305.
Complete drainage pumping and filling are facilitated by working
with gravity. Tank 501 has an excess of capacity of the largest
perimeter hose volume. A pump 502 with valving for pressure and
suction device connects to service hose 503. Air pump 501 hastens
water delivery.
[0073] The present invention also provides other labor and cost
saving aspects compared to the prior art systems. For example:
[0074] Gathering of the side curtains by having the cords reach
under the bottom perimeter of the tarp sides makes a neater
appearance to the folded up tent and takes up much less space. This
is partially due to the elimination of the side gathering tubes;
(the support rigging and the tubes themselves caused bulk in the
folded condition.) Two advantages result here: first is reduced
height of the raised total frame and tarp, second is increased ease
of installation of the evacuation tubes from fans at the end of the
fumigation process. Previously, these had to be installed under the
semi-stiff horizontal pipes which made for a less well sealed
procedure and also required additional labor to lift side tube
weight for insertion of the evacuation hose.
[0075] Tarp over frame construction allows the tarp more even
support so it can be of thinner material improving packing ability
and reducing weight thus requiring fewer winches for a given tent
size.
[0076] The preferred present invention triangle truss provides a
space for supply wiring for the truss mounted circulation fans
which may be permanently connected via spring retractable cord
winders ceiling mounted above the tent. Also the many sniffer
sampling tubes required by the USDA agency can be stored in the
truss frame and uncoiled as needed.
[0077] Obviously, numerous modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
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