Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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THERMAL DOOR SYSTEM
Back~round of the Invention
1. Field of the Invention
The present invention relates to portal closures
providing a thermal barrier, and more particularly to doors
that are capable of being rapidly deployed between an open
and a closed position thereof while providing an improved
barrier to convective, conductive, and radiant transfer of
thermal energy through the doorway so closed.
2. Description of the Prior Art.
In many industries, such as frozen food
proce~sing and distribution facilities, lar~e storage rooms
are provided with environmental control systems to maintain
appropriate temperatures or other environmental factors
within such rooms. Often, however, products being produced
or stored under such controlled conditions are subject to
rapid, high volume, relocation to or from processing areas,
storage areas, or shipping areas, either of which can result
in the need for providing frequent access to and from the
controlled environment area. A typical form of transfer
between such an environmentally controlled area and other
locations utilizes fork lLft trucks or other similar
vehicles to handle palletized units of such products. The
passage of such vehicles, with or without their loads, to
and from the environmentally controlled area is usually
facilitated by providing a portal through which such
vehicles may pa~s. Dependent, of course, upon the degree to
which the environment within the controlled area is to be
maintained, closure of such portals except when absolutely
necessary ~o permit passage of a transfer vehicle is a
primary consideration of design. Several such systems are
known in the art, each varying by compromise between
rapidity of deployment and efficiency of isolation of the
controlled area from its surroundings.
One well known method of partial enclosure of
such a transit portal utilizes a moving air screen to
separate the controlled region from the adjacent non-
controlled region. The air screen, supplied by laminar flow
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blowers directed across the area of the portal, generally
requires movement of large volumes of air, and also usually
requires a closed, high air volume, return system to prevent
inordinate air currents either within the controlled area or
in the adjacent region. The clear advantage exhibited by
such an approach is that no obstacle is presented to impede
or obstruct traffic transiting the portal. However, while
the moving air screen may significantly preclude convection
current transfer of thermal energy into or out of the
controlled area, radiation transfer of thermal energy is not
blocked. Thus, ea~e of passage of traffic through such a
portal is obtained at the expense of compensating for
radiant energy lo~es affecting the controlled environment
in addition to the expense of operation of the blower~ and
exhausts establishing the air screen.
A second approach observed from the industry
utilizes a flexible partial enclosure of the portal, usually
configured as a plurality of vertically oriented flexible
strips depending from an overhead ~upport, the strips being
~o dispoRed on the support that, when no traffic is
tran~iting the portal, the strips depend in substantially
ad~acent positions to es~entially fill the vertical planar
area of the portal. When traffic pa~qes through the portal,
the flexibility of the strips allows such traffic to push
the strips upwardly or aside until the traffic has cleared
the portal. By an appropriate selection of materials used
in forming such strips, some measure of thermal insulation,
in a direction of traffic flow, can be provided when the
strips are hanging dormantly in their respective portal
closing attitudes. While such strips are generally formed
to be transparent for safety purposes, some measure of
blockage of radiant thermal energy transfer can be provided
through selective coating of the strips. Clearly, howe~er,
when rigorous control of the environment within the
controlled area is es~ential, a flexible strip closure is of
limited utility due to the number of slits between adjacent
strips, which would allow convection current transfer of
thermal energy through the portal, and due to indeterminate
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closure of the portal arising from the flexibility of the
strips allowing them to wave about their dormant positions
for a period of time following transit of a vehicle through
the portal. Some of the convection transfer loss can be
prevented by incorporating a moving air screen adjacently
parallel to the plane of the strip closure.
Another approach gaining acceptance in the
industry utilizes a vertically rollable door mechanized to
have rapid opening and closing deployment operation. The
portal closing material, formed a~ a planar flexible sheet,
is carried on a horizontally supported reel above the
portal. The planar sheet has sufficient width to span the
width of the portal and to include vertical edge portions
riding upwardly and downwardly in channels adjacent the
jambs of the portal, thereby substantially closing the
portal when the door is deployed to its fully closed
position. An appropriately flexible lower fringe portion
can be included on the door to adaptively form to the floor
across the portal width to aid in sealing again~t convention
current thermal energy transfer through the portal. In use,
a vehicle seeking to transit through the portal must
approach the portal, the door must appropriately operated to
open the portal to allow the passage to occur, and the door
must be operated to reclose the portal when the vehicle has
completed its passage through the portal.
Such an approach can significantly limit
convection current transfer of thermal energy through the
portal to such times as the door is not fully closed.
Moreover, blockage of radiant thermal energy transfer
through the portal can obtain by the interposition of the
door closing the portal. Heretofore, however, the
compromise between blockage of energy transfer through a
door closing the portaL and the need for rapid deployment of
such a door to limit the loss of environmental control
during timeq when the door is fully or partially open has
been driven toward rapid deployment of the door rather than
selection of materials for the door that would maximize
resistivity to all forms of thermal energy transfer through
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the door. Indeed, the factors favoring rapid deployment
appear dominant in that losses through an open portcll far
exceed those through a closed portal, regardless of the
manner of closure of the portal. Howeverr when traffic
volume through the portal is light, such that the portal
would be closed a significant portion o~ the total time, the
losses through a closed door increase in importance.
Ideally then, a system that maximizes the rapidity of
deployment operations of the door, appropriately limits the
open statu~ of the door to that only essential to complete
traffic pa~age ~hrough the portal, and minimizes losses
through a closed door, i~ a desirable re~ult.
Unfortunately, door materials heretofore available that are
compatible with or adaptable to rapid deployment systems
were constrained to be of light weight, thereby limiting the
resistivity to thermal energy transfer through their
thickness. Additionally, such earlier materials, and the
manner of their use in rapid deployment door systems, do not
reasonably allow such doors to provide other beneficial
results, such as fire retardation and entry ~ecurity.
Summarv of the Invention
Accordingly, it is an object of the present
invention to provide a material for incorporation into a
rollable portal closure that provides a significant thermal
barrier to conductLve and radiant thermal energy transfer
across its thickness.
It is another object of the present invention to
provide a material for incorporation into a rollable portal
closure that provides a temperature and fire barrier across
its thickness.
It is an additional object of the present
invention to provide a material for incorporation into a
rollable portal closure having resistance to penetration
through its thickness.
It is a further object of the present invention
to provide a material for incorporation into a rollable
portal closure that may be combined with a laceration
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resistant combination of elements to provide entry security
to the portal so closed.
Another object of the present invention is to
provide a rollable portal closure system utilizing either of
the materials provided herein.
An additional object of the present invention is
to provide a rollable portal closure system incorporating
eith~r of the materials provided herein in concert with a
plurality of vertically spaced apart, horizontally disposed,
flexure inhibiting members within layers of said materials.
A further ob~ect of the present invention is to
provide a rollable portal closure system including means for
precluding impact on said closure by a vehicle attempting to
transit said portal.
Yet another object of the present invention is
to provide a rollable portal closure system providing a
significant fire retardation factor.
Yet a further object of the present invention is
to provide a rollable portal closure system providing
improved security against unauthorized entry through said
closure.
These, and other objects, advantages, and
features of the present invention that may become apparent
through the hereinbelow descriptions of the principal and
alternate embodiments of the pre~ent invention, are provided
by a rollable doorway closure system comprising a reel
mechanism, means for driving said reel mechanism, a thermal
barrier door carried to roll onto and from said reel
mechanism, guides for deployment of said door, means for
controlling the deployment of said door, and means for
impeding traffic through said doorway when said door is
closed, said elements being operatively combined as
indicated by the following descriptive disclosures.
The door is generally comprised of a uni-
directionally flexible laminate formed of materials
providing a high resistivity to thermal energy conduction
across the thickness of the laminate. The laminate is
further formed to have its generally planar surfaces covered
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with reflective radiant energy barrier material, bonded
thereto, such that the material, highly reflective of
radiant thermal energy, is capable of flexing with the
laminate in at least the preferred direction.
The reel, generally disposed in a substantially
horizontal orientation spanning the width of a portal or
doorway, accepts the door in a rolled-up configuration to
enable the portal to be in an open condition, and supports
an upper horizontal end of the door when the door is
deployed downwardly to close the portal. The reel is
provided with a controllable drive mechanism for rapidly
rotating the reel about it~ horizontally oriented
longitudinal axis.
In the principal embodiment of the invention,
vertical guides are deployed adjacent each jamb of the
portal, into which guides vertically oriented edges of the
door are respectively engaged so as to slide vertically
therewithin as the door is reeled or unreeled upwardly or
downwardly during opening or closing of the portal.
Control of the operation of the door, as~umed to
be in a normally closed position with the door unreeled from
the reel so as to contact a floor of the portal, is
preferrably mechanized by sensors that detect the approach
of a vehicle seeking to transit through the portal, the
sensor~ generating a Rignal to cause ~ctuation of the reel
driving mechanism to result in appropriate reeling of the
door. The sensors also communicate completion of the
passage of the vehicle through the portal to actuate closing
of the door.
Since the speed of a vehicle approaching or
transiting through the portal can be a variable dependent on
such factors as environmental conditions, load on the
vehicle, traffic frequency, and vehicle operator
preferenceY, the herein sy~tem is further provided to
include means for impeding the progress of the vehicle
toward the door until the door has sufficiently opened to
enable the vehicle to transit the portal without impacting
upon the door. Mechanization of such means can typically
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take the form of hydraulically or pneumatically operated
skid ramps embedded into the floor of the vehicle path
proximate to the portal to be level with the floor when the
door is open. Such skid ramps, when deployed upwardly from
the floor while the door is closed, engage lower structural
surfaces of the vehicle cha~sis such that the continued
progress of the vehicle toward a closed door will cause the
vehicle to slide upwardly along the skid ramps to lift the
vehicle driving wheels from contact with the floor, therby
stopping the vehicle. In operation, such ramps are
typically deployed to the~r elevated positions when the
portal i~ clo-~ed by the thermal barrier door. Ag a vehicle
approaches the portal for transit therethrough, the
appropriate passage sensors detec~ the vehicle and provide a
signal causing the reel driving mechanism to activate so a~
to roll the door upwardly onto the reel. When the door has
opened sufficiently to allow the vehicle a clear passage
through the portal, a position switch, incorporated on the
door or on the reel, provides a signal to a control system
which retxacts the skid ramps to their positions level with
the floor surface, thereby enabling the ~ehicle to progress
toward and through the portal. When pa~sage of the vehicle
away from the portal i8 sensed, a further control signal is
generated and used to actuate the reel drive mechanism to
unroll the door to its closed position and also to deployed
the skid ramps to their raised positions.
A first alternate embodiment of the door is
envisioned to include forming the door as a double thickness
of the aforesaid reflective radiant barrier covered thermal
barrier laminate having a substantially dead air space
between the two thicknesses. A plurality of horizontally
disposed guide bars are vertically spaced apart within the
dead air space so as to provide the door with increased
flexure stiffness across the width of the door. The guide
bars are suspended from the reel supporting structure by a
flexible support network that enables the guide bars to be
gathered from below as the door is raised and rolled onto
the reel, such gathering being accompiished in a manner that
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the guide bars are not rolled onto the reel. A simple form
of such a suspension network has a design parallel in the
common venetian blind. In such a method, each end of each
guide bar is supported by a flexible support element from
the proximate end of the guide bar disposed immediately
thereabove, the flexible support elements each having an
equal, non-extendable, length. When the door is unrolled
from the reel to its fully clo~ed position, the guide bars
are equally vertically spaced apart, with the flexible
support elements each at their maximum ex~ent. As the door
is rolled onto the reel, the lowest guide bar is first
elevated by the lowermost edge of the door, collapsing
accordingly the flexible support elements form which it
depends ~rom the next lowest guide bar, until -the lowest
guide bar has been raised into contact with the next lowest
guide bar, at which elevation, the lowest and the next
lowest guide bars continue to be elevated by the lowermost
edge of the door, collapsing accordingly the flexible
support elements by which the next lowest guide bar depends
from the guide bar immediately thereabove. In a like
m~nner, all of the guide bars are similarly gathered, in
sequence from lowest to highest, until the door has been
fully opened. It should be noted that this embodiment of
the thermal barrier door system requires that the reel be
disposed at an elevation sufflciently above the vertLcal
clear span of the portal so that the plurality of guide bars
gathered during raising of the door will remain within the
dead air space of a portion of the door not rolled onto the
reel at the fully open position of the door. Throughout the
deployment and gathering of the guide bars, each end of each
guide bar continues in engagement with a vertical guideway
a~sociated with the vertical guides adjacent the jambs of
the portal.
A further alternate embodiment of the door of
the present invention envisions incorpoxating a loosely
interlocked mesh, in lieu of the guide bars, within the dead
alr space described above. Such a mesh serves as a security
barrier against laceration entry through a closed door. The
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mesh is generally sufficiently flexible to accomodate being
rolled onto the reel with the door layers, however, it may
alternately be freely suspended within the dead air space
below the reel so as to be gatherable from below as the door
is raised, much like the aforesaid guide bars. Such a mesh
may, in the alternative, be rolled up with the outer two
layers of the door. The mesh may also be formed as a
plurality of spaced apart rigid elements, each extending
across the door parallel to the free end of the door, this
plurality of elements being linked together by multiple
flexible links extending along the door oxthogonally to the
rigid elements.
Other alternate embodiments may be readily
determined by consideration of the requirements for the
several component elements and systems of the present
invention. Such alternate embodiments, such as mechanizing
the vehicle transit sensors as lasers or other velocity
sensors, or as mere hand or foot operated switches, or as
mechanizing the closed door transit impeding device as a
full barrier, are envisioned to be substantially equivalent
to the herein described embodiments. Additionally, it i9
envisioned that the approach herein disclosed for providing
an improved thermal barrier, which includes fire and entry
security, may be mechanized in a form having side to side
opening and closing motions. The scope of the present
invention shall therefore be limited only by the terms of
the claims allowed thereinO
Brief Description of the Drawina
In the accompanying drawing, wherein like
reference numbers and symbols are employed to refer to like
elements:
FIG. 1 is a perspective view of a thermal door
system in accordance wi~h the present invention;
FIG. 2 is a cross-sectional end view of a
thermal door and reel mechanism in accordance with the
present invention;
FIG. 3 is a fragmentary perspective view of a
vehicle transit impeding mechanism of the present invention;
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FIG. 4 is a fragmentary perspective cross-
section of a thermal door in accordance with a principal
embodiment of the present invention;
FIG. S is a fragmentary perspective cross-
section of a first alternate embodiment of a thermal door in
accordance with the present invention.
FIG. 6 is a cross-sectional end view of a
thermal door and reel mechanism in accordance with the first
alternate embodiment of the thermal door, illustrating the
door deployed to three positions thereof, FIG. 6~ showing
the door deployed to a fully closed position, FIG. 6B
showing the door deployed to a position intermediate of the
fully closed position and a fully open position, and FIG. 6C
showinq the door deployed to the fully open position;
FIG. 7 is a fragmentary perspective cross-
section of a second alternate embodiment of a thermal door
in accordance with the present invention; and
FIG. 8 is a cross-sectional end view of a
thermal door and reel mechanism in accordance with the
~econd alternate embodiment of the thermal door,
illustrating two methods for accomodating a mesh
incorporated into said thermal door, FIG. 8~ showing a
partially open door wherein the mesh is reeled onto the reel
along with the thermal door, and FIG. 8B showing a partially
open door wherein the mesh is gathered upwardly from a
lowermost end thereof so as to not be rolled onto the reel.
Detailed Description of the Invention
Referring first to FIG. l, a rapidly deployable
thermal door system is indicated generally at lO. Such a
thermal door system ln comprises, in its most essential
embodiment, a de~loyable thermal door Ll su~ported from an
overhead reel mechanism l~, vert.ica1 guides 13 for governing
deplo~nent of the door l1, a controllab1e driving mechanism
14 for operation of tlle reel mechanism 12, sensors 16 for
detecting vehicles and the like seeking transit through a
doorway 17 at which the door ll is deployed, vehicle braking
devices 18 to preclude impact of a vehicle onto a closed
door ll, and means for relating signals from the sensors 16
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and signals indicating the open or closed status and
position of the door 11 so as to controllably operate the
driving mechanism 14 and the vehicle braking devices 18 in
appropriate sequence and rates to enable passage of a
vehicle through the doorway 17 while maintaining the door 11
in its closed position at all times not necessary for such
vehicle pa~sage.
As illustrated, the preferred utilization of the
thermal door system 10 of the present invention provides for
appropriately attaching the reel mechani~m 12 and it~
associated driving mechanism 14 to a wall 19 of a structure~
separating regions to be isolated by the thermal door 11, in
a manner such that a longitudinal axis of the reel mechanism
12 is disposed in a substantially horizontal orientation
parallel with the wall 19 spanning the width of the doorway
17. In an upwardly deployed, or open, position, the thermal
door 11 is rolled substantially, but not entirely, onto the
reel mechanism 12. When the door 11 is fully deployed to
its closed position, a lowermost end 20 of the door 11
contacts a floox 21 across the width of the doorway 17. The
~o deployed door 11 includes vertical edges 22 which
slidably translate vertically within the vertical guides 13
such that the door 11 is in close proximity to the wall 19
at the upper and side peripheral boundaries of the doorway
17. The combination of the close proximity of the door 11
to the peripheral boundaries of the doorway 17, the contact
of the lowermost end 20 of the door 11 with the floor 21,
the enclosure of the vertical edges 22 of the door 11 within
the vertical guides 13, and the attachment of the reel
mechanism 12 to the wall 19, provides that the doorway 17 is
substantially completely closed by a door 11 so deployed to
its closed position, thereby precluding convection current
thermal energy transfer through the doorway 17 or around the
door 11 and its associated structure.
In use, the doorway 17 i typically par~ of a
vehicle transit path between an environmentally controlled
enclosed area of a structure and surrounding or adjacent
enclo~ed or exterior areas. The effectiveness of the
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aforesaid thermal door 11, deployed to its closed position,
in precluding convective thermal energy transfer through the
doorway 17 contributes significantly toward reducing energy
expenditures for maintaining the environment within the
enclosed controlled area. Minimizing the energy losses
arising during transit access to and from the
environmentally controlled enclosed area is then a primary
concern requiring that the transit doorway 17 be so closed
by the door 11 at all times not absolutely necessary to the
accomplishment of such transit through the doorway 17. To
that end, the driving mechanism 14 is directly coupled to
the reel mechanism 12 such that the reel mechanism 12 may be
driven to rotate about its longitudinal axi~ 23 at a high
rotational velocity in either direction. In similar
systems, deployment of the door 11 from its fully open
position to its fully closed position, or vice versa, may be
accomplished in a nominal period of less than five seconds.
Even more rapid deployment may be achieved by coupling the
drive mechanism 14 to also positively translate the
lowermost end 20 of the door 11 vertically within the guides
13, and by equipping the drive mechanism 14 with a limiting
brake system to avoid bounce at either end of the deployment
operation thereof. While a vertically translating door 11
is described as the principal embodiment of the present
invention, it may be readily noted that minor modifications
to the described system 10 would enable its use in a manner
wherein the door 11 is deployed to translate in a
substantially horizontal direction.
A smooth flow of traffic through the doorway 17,
while maximizing the closed periods of the doorway 17, is
enabled by the incorporation of the senors 16 at appropriate
positions within the environmentally controlled area and
external thereof whereat the transit of a vehicle
approaching or departing the doorway 17 may be sensed and a
signal generated therefrom to actuate the driving mechanism
14 to deploy the door 11 to the proper position. A typical
form of a sensor 16 utilizes a photocell 24 responsive to
laser rays or other forms of directed energy, which, when
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the path between a source 26 and the photocell 24 is
interrupted by passage of a vehicle, causes the output of
the photocell to drop, thus forming a signal for
transmission to the driving mechanism 14. Appropriate
sensing of the resumption of receipt of energy by the
photocell 24 from the source 26 can be used to control
closure operation of the door ll. Appropriate time delays
may be incorporated in the control system to allow for
completion of tran~it of the vehicle through the doorway 17.
A m~re sophistlcated approach to controlling the
operation of the door 11 utilizes two pairs of sensors 16,
one pair disposed adjacent the vehicle path external of the
doorway 17 and the other pair disposed ad~acent the vehicle
path internal of the environmentally controlled area. Each
of the sensors 16 is so oriented as to detect the passage of
a vehicle toward or away from the doorway 17. The sequence
in which the sensors 16 detect the vehicle is used to
detexmine the direction of travel of the vehicle. The time
increment between sen3ing by the sensors 16 of one of the
pairs is used to determine the speed of the vehicle so that
the control system may appropriately adjust a time delay in
actuating the driving mechanism 14 so that the door 11 is
opened or closed at the proper instant to minimize the
period during which the door 11 is open.
Other alternate embodiments of the sensors 16
can be readily envisioned to be in the form of magnetic
pickup sensing coils embedded in the vehicle path so as to
be responsive to magnets on the vehicle chassis, or in the
form of pressure sensitive plates embedded in the floor of
the vehicle path, or even in the form of a radar like
transceiver installed proximate to the wall l9 adjacent the
doorway 17 so as to generate signals and receive return echo
signals from the vehicle. All such embodiments, including
the principal embodiment herein, have the common purpose of
sensing the approach of a vehicle toward the doorway 17 at
an appropriate time to enable the door 11 to reach its open
position just as the vehicle begins its transit through the
doorway 17, and that the door 11 remain in its open position
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no longer than necessary for the vehicle to complete its
transit through the doorway 17.
It is clear that in order to so minimize the
time increment during which the door 11 is not in its fully
closed posi~ion, to accomodate passage of a vehicle through
the doorway 17, knowledge of the speed of travel of the
vehicle is an essential factor. However, even in
embodiments providing information about the speed of the
vehicle, the speed of the vehicle may be varied by the
vehicle operator to be such that the vehicle would arrive at
the doorway 17 before the door 11 can open sufficiently to
avoid impact of the vehicle into the door 11. To safeguard
against ~uch unintentional impacts, whlch could result in
serious damage to the door 11 and loss of environmental
control integrity of the door 11, the thermal door system 10
is provided with vehicle braking devices 18, disposed
appropriately along the vehicle path both within the
environmentally controlled area and external thereof. Such
devices 18, as will be more fully understood from a detailed
deRcription hereinbelow, are disposed along the vehicle path
appropriately removed from proximaity to the doorway 17 so
that they will stop a vehicle approaching the doorway 17
before the vehicle can impact on the door 11 or enter into
the doorway 17 until the door 11 is sufficiently open to
allow an unimpeded transit through the doorway 17 by the
vehicle. Such braking devices 18 are therefore nece~arily
interlocked, for their operational control, with the sensors
16 and with an indication of the vertically deployed
position of the door 11. The interlocking is coupled
through the control system such that the braking devices 18
remain deployed to stop vehicle progress until the
indication of the vertically deployed position of the door
ll is that the door 11 is open, at which time the braking
devices 18 are retracted. The braking devices 18 then
remain retracted until the transiting vehicle has departed
from the doorway 17, as established by the sensors 16.
Referring next to FIG. 2, the principal
embodiment of a door 11 and reel mechanism 12 of the present
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invention is shown in cross-section. The door 11 is formed
as a laminate capable of readily flexing about parallel
horizonal lines across the width of the door 11, normal to
the plane of FIG. 2, while the laminate retains stiffness
against flexure about vertical parallel lines through the
door 11, in and parallel to the plane of FIG. 2. The
particular construction of the principal embodiment of the
door 11 will be described more fully hereinbelow. The
differential flexure capability of the laminate allows the
door 11 to be rolled onto the reel mechanism 12 as the door
11 is opened, while also providing a measure of stiffness
across the width of the door 11. The reel mechanism 12
comprises a drum 27, journaled at either horizontally
disposed end to rotate about a longitudinal axis 23 of the
reel mechanism 12, in either rotational direction, under
action of the driving mechanism 14 of FIG. 1. The
longitudinal axis 23 of the reel mechanism 12 is supported
from the ad~acent wall 19 by attachment of a reel housing 29
thereto 3uch that the longitudinal axis 23 and the drum 27
are sufficiently horizontally spaced ap~rt from the wall 19
to allow freedom of rotation of the drum 27, even when
multiple layers of the laminate forming the door 11 are
rolled onto the drum 27 as the door 11 is fully opened. The
llousillg 29 is provided with a generally downwardly directed
guiding opening 30 through which the door 11 progresses as
it is unrolled from the drum 27, said opening 30 being
substantially ad~acent the wall 19.
Referring next to FIG. 3, the vehicle braking
device is shown in greater detail to comprise, in a
principal embodiment thereof, a hydraulic cylinder 31,
having a longitudinal axis, pivotably coupled at a first end
32 thereof, to a bracket 33 securely anchored to a lower
surface 34 of a hole 36 formed in the floor 21 of the
vehicle transit pathway, a piston 37 extending along the
longitudinal axis 28 from a second end of the cylinder 31
obverse to the first snd 32 thereof, to be pivotably coupled
proximate to a first end 38 of a plate 39. A second end of
the plate 39 is hinged about an axis 40 disposed
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substantially coplanar with the surface of the floor 21.
Hydraulic supply lines 41 couple the cylinder 31 to a
controllable pressurized hydraulic supply (not illustrated).
The piston 37 and cylinder 31 are in their most extended
mutual positlons when the door 11 is not sufficiently open
to allow vehicle transit through the doorway 17. The
extension of the piston 37 from the cylinder 31 causes the
plate 39 to as~ume a pivoted pocition about the hinge axis
40 such that the first end 38 of the plate 39 is elevated
above the surface of the floor 21 sufficiently to form a
ramp which will engage lower surfaces of the undercarriage
of a vehicle attempting to progress toward the doorway 17,
thereby causing the vehicle to be raised a~ it climbs along
the ramp formed by the plate 39 until the dr~ve wheels of
the vehicle are lifted from contact with the floor 21,
precluding further progress of the vehicle. When the door
11 is in an open position sufficient to allow passage of the
vehicle through the doorway 17, appropriate control signals
generated by the sensors 16 and the door position are
provided to the controllable hydraulic supply to actuate the
cylinder 31 so as to retract the piston 37 therewithin,
pivoting the plate 39 downwardly about the hinge axis 40
until the plate 39 is substantially coplanar with the floor
21, concurrently lowering the vehicle drive wheels into
contact with the floor 21 so that transit of the vehicle
through the doorway 17 may conti~ue. Completion of passage
of the vehicle through the doorway 17 pro~ides a further
control signal to the hydraulic supply so as to cause
actuation of the cylinder 31 and piston 37 to redeploy the
plate 39 to its ramp forming upwardly pivoted position. In
a normal operation of transiting vehicles through the
doorway 17 at appropriate vehicle speeds, the door 11 is
opened and the plate 39 is accordingly retracted without
impeding vehicle progress.
Referring next to FIG. 4, construction of a
principal embodiment of the thermal door 11 is shown by the
illustrated ~ragmentary perspective cross-section thereof.
The door 11 is, as stated earlier herein, a laminate. The
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primary rigidity of the door 11 results from a laminated
material, shown in the enlarged fragmentary view (FIG. 4B)
of door 11, comprising a generally resinous base material 42
having a plurality of corrugated flexible sheets 43 embedded
therein such that their respective corrugations are
substantially mutually parallel to extend across the width
of the laminate in a direction indicated by arrows 44.
These corrugations provide strength of the laminate to
inhibit .flexure about axes in the plane of the door 11
normal to the arrows 44, while allowing flexure of the
laminate about axes in the plane of the door 11 parallel to
the directions indicated by the arrows 44.
The materials chosen to form the laminate are
further constrained to be such that pro~ide substantial
thermal resistivity to conduction of thermal energy across
the thickness of the laminate, from a first planar surface
46 thereof to an obverse, second planar surface 47 thereof,
and vice versa. The aforesaid laminate is additionally
provided with thermal energy reflective sheets 48
appropriately bonded to both planar surfaces 46, 47 of the
laminate, thereby significantly limiting radiative thermal
energy transfer across the thickness of the door ll. The
inclusion of the thermal energy reflective sheets 48, by
inhibiting radiative thermal energy transfer from a source
thereof external to one side of the door 11, provides an
added benefit in enhancing the use of the door 11 as a fire
barrier protecting the area to the side of the door 11
obverse to the source of thermal energy. The nature of the
reflective sheets 48 is such that each surface of each sheet
48 reflects at least ninety five percent of the radiant
thermal energy incident thereon, with a result that no more
than 0.000625 percent of radiant thermal energy from a
source thereof incident on ~he door 11 will be radiated
outwardly from the obverse surface of the door 11.
Referring next to FIG. 5, a first alternate
embodiment of a thermal door in accordance with the present
invention is indicated generally at 49. The door 49
generally comprises a pair of reflectively covered laminates
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separated by a dead air space 50 in which are deployed a
plurality of horizontally disposed bars 51. Each of the
reflectively covered laminates of the pair is, in all
respects of construction, identical with the door 11 of FIG~ .
4. In particular, in progressing through a thickness of the
door 49, the laminate layers encountered are, sequentiallyr ~ j
a thermal energy reflective sheet 48, a laminate of the base
material 42 and a plurality of corrugated sheets 43 bounded
by planar surface 46, 47, a second thermal energy reflective
sheet 48, the dead air space 50 which may include a bar 51~
a third thermal energy reflective sheet 48, a second
laminate of the base material 42 and a plurality of
corrugated sheets 43 bounded by planar surfaces 46, 47, and
a fourth thermal energy reflective sheet 48. The lowermost
ends 20 of each of the pair are joined together across the
width of the doorway 17. The preferred manner of joining
the lowermost ends 20 together is to form the pair as a
single continuous laminate looped at the lowermost end 20.
The plurality of bars 51 depends from the reel
mechanism 12 independently of the door 49. The bars 51 are
vertically spaced apart by substantially equal distances
when the door 49 is deployed to its fully closed position.
The bars 51 each extend fully across the width of the
doorway 17 to extend outwardly, at each end of their
respective extent, from the vertical edges of the door 49,
to engage separate vertically disposed guideways (not
illustrated). When the door 49 is fully closed, the bars 51
provide additional rigidity against impact and side-to-side
flexure of the door 49.
Referring next to FIG. 6, the manner in which
the bars S1 of the door 49 are suspended, and their
disposition relative to the reel mechanism 12 during
differing stages of deployment of the door 49, is indicated
with reference to three deployment positions of the door 49:
FIG. 6A illustrating the door 49 in its fully open position;
FIG. 6B illustrating the door 49 deployed to a position
intermediate between its fully open and its fully closed
positions; and FIG. 6C illustrating the door 49 in its fully
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closed position. When the door 49 is in its fully open
position, the pair of laminate combinations are both rolled
up onto the drum 27 of ~he reel mechanism 12 such that the
dead air space 50 is substantially collapsed and the
surfaces of the laminate combinations are in mutual contact~
The bars 51, having been gathered by the lowermost end 20 of
the door 49, are di~posed in substantially mutual contact
within a residual portion of the dead air space 50 between
the pair of laminate combinations at a residual lower
portion thereof depending below the guide opening 30 of the
reel housing 29. It should be noted hereat that the reel
housing 29 and the guide opening 30 are to be appropriately
enlarged from those of the principal embodiment so that they
may accomodate the doubled thickness of laminate
combinations forming the door 49.
As the door 49 is deployed from its fully open
position of FIG. 6A, the bars 51 are, as a group, lowered
with the lowermost end 20 of the door 49 until a flexible
bar suspending element 52, having a fixed length from its
support on the reel housing 29 to the uppermost bar Sl,
reaches its substantially non-extendable length, thereby
precluding further downward movement of the uppermost bar
51. As the door 49 continues therefrom in its downward
deployment toward its closed position, all of the bars 51
except the uppermost bar 51, continue to progress downwardly
along with the lowermost end 20 of the door 49 until a
second bar suspending element 53, extending from the
uppermost bar ~1 to the next proximately lower bar 51,
reaches its extended length, whereat the second bar 51
becomes suspended at its intended fixed elevation. As
indicated by FIG. 6B, this process of deploying the bars 51
continues from the top of the door 49 downwardly, with any
intermediate position of the door 49 providing for a number
of bar~ 51 being disposed at their intended elevations and
the remainder of the bars 51 continuing to rest in mutual
sequential contact supported by the lowermost end 20 of the
door 49. Each succeedingly lower bar 51 is coupled to the
bar 51 disposed next proximately higher thereto by a bar
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suspending element ~3. In the usual manner of suspending
the bars 51, each end of each bar is provided with the
appropriate suspending elements 53.
When the door 49 has reached its fully closed
position as shown in FIG. 6C, all of the flexible bar
suspending elements 53 have re~ched their respective ~ i
extended lengths and the bars 51 are deployed to their
respective vertically spaced apart elevations. In most
configurations of the door 49, it is generally desirable
that the lowest bar 51 be proximate to the lowermost end 20
of the door 49 when the door 49 is in its fully closed
position, as will be further explained later herein.
Referring next to FIG. 7, a second alternate
embodiment of a thermal door in accordance with the present
invention is indicated generally at 54. As can be okserved
from the fragmentary perspective cro~s-section of FIG. 7A,
the door 54 appears quite similar to the door 49 of FIG. 5,
except that the bars 51 of the door 49 are replaced by a
mesh element 56 in the door 54. The mesh element 56 shown
in the enlarged fragmentary view (FIG. 7B) of door 54 is
formed as a loosely interlocked plurality of ringlets 57
such that when the door 54 is deployed to its fully clo~ed
position, the ringlets 57 are substantially uniformly
distributed within the dead air space 50 between the pair of
laminate combinations forming the door 54 so as to fully
cover the planar area of the door 54. The ringlets 57, by
being interlocked to each other in all planar directions of
the doox 54, provide for security against entry through the
door 54 which may be attempted by using a technique of
penetration and laceration of the laminate combinations. If
the material chosen for the ringlets 57 is sufficiently
durable, laceration of the ~oor 54 sufficient to provide an
opening necessary for unauthorized entry through the door 54
is precluded by the mesh element 56.
The mesh element 56 may alternately be formed as
a plurality of spaced apart, substantially rigid, wires
extending across a width of the door so as to be
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substantially parallel to the free end of the door. These
wires are linked together by a number of flexible members
extending along the length of the door so as to ret~in the
rigid wires in their respective positions.
Referring lastly to FIG. 8, deployment of a
thermal door of the type illustrated in FIG. 7 as the door
54, to include a mesh element 56, is accomplished by rolling
the door 54 onto and from an appropriately configured drum
27 of a reel mechanism 12 in an appropriately sized housing
29, as has been heretofore described. However, the
inclusion of the mesh element 56 provides that two
alternative methods of rolling the door 54 onto the drum 27
are feasible. A first method, as shown in FIG. 8A, wherein
the door 54 is illustrated to be in an intermediately
deployed position, utilizes the looseness of the
interlocking of the ringlets 57 to enable ~he mesh element
56 to be rolled onto the drum 27 along with the laminate
combinations forming the door 54. The looseness of the
interlocking of the ringlets 57 forming the mesh element 56
is such that the mesh element 56 does not substantially
increase the resistance to flexure of the door 54 in either
direction along the planar surfaces of the door 54. A
second method, shown in FIG. 8B, provides for the
utilization of a smaller configuration o~ the drum 27, reel
housing 29, and guide opening 30 by independently supporting
an uppermost end of the mesh element 56 from the reel
housing 29 such that the looseness of the interlocking
between the ringlets 57 allows gathering of the mesh element
56 from the lowermost end 20 of the door 54 as the door 54
is raised from its closed position, much in the manner that
the bars 51 of the door 49 of FIG. 5 and FIG. 6 are
gathered. The fully gathered mesh element 56 is, in this
method, stored in a residual dead air space between the
laminate combinations depending below the reel housing 29
when the door 54 is at its fully open position.
With reference to the drawing in general, in
either of the embodiments described, the lowermost end 20 of
the door may be driven along with operation of the reel
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mechanism 12 by the inclusion of appropriate pulley, cable,
and spring components within the vertical guides 13. Such
further mechanization of the operation of the thermal door
enhances the capability for rapid deployment thereof despite
any random flexure in the deployment direction inherent in
the laminate combination used to form the door.
Accomplishment of this added feature require that the
lowermost end 20 of the door be provided with a
substantially rigid member extending across the width of the
doorway 17, such member being firmly coupled to the
lowermost end 20 of the door. Such a rigid member spanning
the lowermost end 20 of the door 54 of FIG. 7 and FIG. 8
will also provide a lowermost anchoring member for the mesh
element 56 to prevent unauthorized entry by a laceration of
the lower end 20 and a subsequent gathering of the mesh
element 56 upwardly therefrom.
While the foregoing has presented detailed
descriptions of a preferred and alternate embodiments of a
thermal door system in accordance with the present
invention, it is envisioned that such descriptions have also
revealed further alternate embodiments comprised of
permutations of the features and component elements of the
embodiments explicitly set forth. Moreover, it is clear
that reasonable substantially equivalent mechanizations
accomplishing the purposes herein in like manner will be
evident to those knowledgable in the art. Each of such
further embodiments is to be construed as being within the
scope of the present invention, as limited only by the
appended claims.
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