Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to doors and more
particularly to overhead doors which are employed in
industrial applications.
In situations where doors have to be maintained
closed and opened periodically to permit the passage of
vehicle traffic the damage to doors has been frequent and
extensive and their maintenance and replacement has heen
expensive. The direct replacement cost alone is enormous
and the consequential costs may even be greater. For
example in mining applications where sections of a mine are
required to be kept at predetermined pressure if a door is
damaged such that pressure cannot be maintained then the
mine section will be closed.
Present experience indicates that the direct cost
of door replacement may involve hundreds of thousands of
dollars annually in any one mining application.
Many attempts have been made to reduce these
costs. Remote automatic controls for the door opening and
closing operation have been provided through various types
of remote sensing. Driver controlled operation has also
been provided. ~owever, while these systems have improved
damage control they have not proved to be satisfactory.
With remote controls the variable speed of traffic
approaching a door is a limiting factor. It is also a
factor in driver control. In both cases the response time
of the doors is critical and if the driver approaches a
door at a higher speed than that permitted hy the system
response time damage follows. Too slow an approach leads
to a loss of operating efficiency.
The other principal factors in driver control of ~he door
operating functions are the driver's own awareness of the
door presence and his response time. Frequently in dark
situations the driver is just not aware of his approaching
a closed door and damage results.
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The other factor is damage to the vehicle. This
is also considerably expensive and leads to downtime.
With these problems and difficulties in mina, the
present invention provides a damage-minimizing door which
may be used to close vehicular traffic passages. The door
can be easily and economically repaired and maintained. It
will lead to more efficient use of the traffice passage and
minimi~e damage to the vehicle.
According to the present invention, a damage-
minimizing door comprises: a flexible curtain having afirst upper end and a second lower end and side edges; a
curtain winding mechanism said first end of said curtain
being secured to said curtain winding mechanism for moving
said curtain upwards and downwards; and a pair of parallel
spaced apart guide channel means, said side edges of said
curtain being movable in said guide channel means,
sealingly engageable therewith under at least atmospheric
pressure and releasable therefrom at a predetermined impact
force on said curtain.
No door is completely damage-proof but the
present structure has demonstrably reduced damage to hoth
the vehicle and door7 is easily installed and maintained
and may be used in applications of high pressure.
These and other features will be more clearly
~5 understood from the following detailed description and
drawings in which specific embodiments are described by way
of example and in which:
Figure 1 is a general perspective view of one
embodiment of a door structure in accordance with the
present invention with the door curtain in a partially
lowered position and the door bulX-head shown in dotted
outline
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Figure 2 is a general perspective view of the
door illustrated in figure 1 in the door-closed position
and under impact from a vehicle shown in dotted outline and
serves to illustrate the general concept of the invention;
Figure 3 is a front elevation of the door
structure illustrated in Figure l;
Figure 4 is an enlarged fragmentary front
elevation partially in section of the right hand side of
the door structure illustrated in Figure 3;
Figure 5 is schematic end elevation partially in
section taken along line 5-5 of Figure 3 and serves to show
the relationship between a door curtain and its components
and the guides therefore with the door curtain in an almost
completely open position'
Figure 6 is a futher schematic fragmentary end
elevation of a door curtain illustrated in Figure 4 in a
lowered position;
Figure 7 is an enlarged fragmentary perspective
view of the lower end of the embodiment of a door curtain
illustrated in the previous drawings and serves to
illustrate the structural relationship between a base bar
and a curtain:
Figure 8 is a schematic enlarged end elevation of
the bottom of one curtain structure of the type shown in
Figure 6 and serves to illustrate the disconnection under
impact between a base bar and a curtain door;
Figure 9 is an enlarged exploded view of a guide
roller mounting in accordance with the present invention;
Figure 10 is an enlarged front elevation,
partially in section, of a guide roller mounting in
accordance with the present invention;
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Figure 11 is an enlarged perspective view of the
bottom of an alternate embodiment of a door curtain in
accordance with the present invention;
Figure 12 is an enlarged schematic view of the
door curtain illustrated in Figure 12 showing the action
between curtain components under impact;
Figure 13 is an enlarged schematic view of the
bottom of a curtain of a further alternate embodiment of a
curtain in accordance with the present invention;
Figure 14 is a schematic fragmentary end
elevation of an alternate door structure in a lowered
position;
Figure 15 is a plan section of one side of an
alternate curtain structure in accoraance with the present
invention; and
Figure 16 and 17 are further plan sections of one
side of the lower end of alternate curtain structures in
accordance with the present invention.
Referring now to the drawings and more
particularly to Figure 1 it will be noticed that the door
structure itself is indicated at 10 and comprises a curtain
of flexible material. In the embodiments illustrated the
curtains are manufactured of rubber. In the sense in which
the term "rubber" is employed in this specification it
should be understood that it includes any suitable flexible
materials which have resilient capabilities or the capacity
to retain their form. It will also be understood that
where fire is a potential hazard that suitable non-toxic
rubbers or equivalent materials would be employed. Such
rubbers are identified as Type 1 - Wingprene*(neoprene) and
Type 11 - SBR.
* Wingprene is a trade mark
. .
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With structures of the present invention,
depending on the particular application it may be necessary
to provide bulkheads. Such bulkhead is illustrated in
Figure 1 and comprises vertical steel members 11 and 12 and
a cross piece 13.
To each vertical member an inwardly facing guide
channel such as 14 and 15 is secured in aligned opposite
relationships. At the top and on the outerside of the
vertical 11 away from the traffic flow an assembly 16
comprising a motor 23 and clutch 21 is mounted. The motor
may be operated in any conventional manner by remote or
manual controls; the choice depends upon the application.
Curtain 10 is secured along its top edge to a
drum 17 as illustrated in Figures 4 and 5. This securement
may be as illustrated by a series of openings adjacent the
upper end of curtain 10 which are aligned with
corresponding openings in drum 17. Bolts 100 pass through
the aligned openings and are secured by nuts 102. Washers
104 are positioned between each bolt head and curtain 10.
Drum 17 is rotatably supported in mounting brackets 30 &
31, is stepped at 18 to ensure uniform winding and
unwinding of the curtain sheet 10 and is connected through
a shaft 19, chain drive 20, clutch 21, and a worm and screw
22 to a motor 23. Drum 17 is provided at each end with
torsion springs such as 24 as illustrated in Figure 4.
These torsion springs help to wind up the curtain 10. The
springs are coaxial with the winding drum and are connected
thereto at one end of each spring.
As shown particularly in Figures 4, 5, 9, and 12
a guide roller 26 is also rotatably mounted in brackets 30
and 31. Roller 26 is mounted forward and below of the axis
of rotation of drum 10 at a position such that it is at the
top end of channels 14 and 15 and defines one side o a
~:'
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throat to guide the curtain lO. The remaining side of the
throat is defined by a bracket or bar 27 which presents a
downward curved surface toward the adjacent channel mouth.
In Figure 14 an alternate structure is
illustrated. As shown in this drawing the channel 15 is
provided with curved upper ends which curve towards the
idler roller 26. The inner wall 160 of guide channel 15 is
also lockably hinged at 161 so that it may be folded down
when the curtain lO has to be re-inserted in the channel.
As illustrated in Figure 9, roller 26 is
supported at the motor side at least by a plate 33 which
may be adjustably secured horizontally and vertically to
the housing plate 31. Plate 33 in turn supports a
universal bearing 34 which supports a roller shaft 35.
This arrangement facilitates adjustment in mounting the
guide roller 26 in installation and maintenance. The
correct guidance of the rollers and consequently the
curtain is important if the curtain is of rubber since
there is a tendency for rubber to bind against metal and
this will prevent free-running of the curtain.
It is also to be noted that the guide roll 26 is
mounted on that side of the curtain which is presented in
those applications where there is a pressure differential
across the curtain, to the lower pressure side. Under such
conditions the curtain 10 has a tendency to bow to the
negative pressure side and it is necessary to maintain
contact with the curtain to ensure that it runs properly
and keeps in the channels.
The curtain itself is preferably of a hard
flexible rubber composition. On the outside vertical edges
a further strip of rubber, may be provided or the curtain
may be of thicker construction at the edge as shown in
Figure 15. This assists in sealing, particularly in
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applications where higher pressure may be required. In
this context high pressure is meant to include all
pressures within the range 15 lbs./sq.ft. (atmospheric) to
45 lbs./sq.ft. (2.5 Waters GA). The edge strip or
thickened edge while assisting sealing does not increase
the weight of the curtain 10 appreciably.
As shown in Figure 8, base bar 50 comprises a
pair of spaced apart angles 52 and 53 which are connected
by a flat bar 54. Bar 53 is provided with a series of
threaded bolts 153 which pass through and engage a securing
strip 55. It is to be noticed, from Figure 7, that where
the securing strip passes between the walls of the channels
14 and 15 the strip is rounded to ease any friction. This
base bar serves to stiffen the lower end of the curtain.
The lower edge of curtain 10 is passed between
angle 52 and strip 55 and the bolts are tightened so that
the engagement between the bar and the curtain is tight but
releasable. The amount of force required to release the
bar may be adjusted according to the pressure. As will be
apparent this bar also serves to guide the curtain.
In the structures illustrated in Figures 11, 12,
and 13 two alternative structures are provided. In the
structures of Figures 11 and 12 a rubber tube 55 with an
interior coiled spring 56 is substituted for the base bar
and this structure is connected by a grooved channel 57
to the lower edge of curtain 10. In the structure of
Figure 13 a hollow rubber tube 60, closed at both ends is
secured, either permanently or removably to the lower edge
of curtain 10. This tube has a series of holes 61 on the
upper surface. The internal chamber of the tube 10 may
then be filled with a suitable fluid which may be added to
or removed through the holes 61.
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In the embodiments illustrated in Figures 15
through 17 various alternate curtain structures are
illustrated. Corresponding components are correspondingly
numbered in these figures to those of other figures. In
each of these structures the curtain 10 is provided with a
thickened area 110 which may have the alternate
configurations illustrated in the respective figures. In
each structure the guide channel has a throat of reduced
width for restraining movement of the curtain out of t~.e
channel. In Figure 15, the channel is constricted by angle
130; in Figure 16 by opposed angles 131 and 132 and in
Figure 17 by the configuration of the open tube structure
of the channel itself. In each of these structures the
throat is narrower than the curtain edge. This precludes
lateral movement of the curtain 10. It will of course be
understood that the remote lateral side of the curtain and
its corresponding guide channel are of the same structure.
It will of course be understood that flexible or
compressible materials other than rubber may be employed.
In those applications where the pasages of gases
is not important permeable materials may be employed.
The mode of operation of the present invention is
extremely simple. It is assumed that the door 10 is down.
Essentially, if a driver fails to open the door 10 or if it
fails to open before it is hit by a vehicle at impact, as
illustrated in Figures 2, 8 and 12 the vertical edges of
the curtain 10 will be pulled out of their guide channels
14 and 15 in the manner illustrated in the drawings and
will retreat before the vehicle. In addition the base bar
50 or tube 55 may release from the curtain. The vertical
edges will be pulled out irrespective of the height of the
door above the ground as long as it is within vehicle
,
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contact. Thus even if the door is half-way up or down the
same action will hold. Clutch 21 is disconnected and slips
so that shaft 19 is free to rotate. The accurate winding
of the curtain is ensured by guide roller 26, guide bars 27
and the further fact that drum 17 is stepped to ensure
circular winding motion.
Since the curtain is of rubber it will give with
the force and unless it is hit with considerable speed,
more than is normally permissible at least in mining
applications, it will be substantially undamaged. It is
generally a simple and straightforward operation to
reinsert the curtain back into its guide channels and make
the door operational again. With the embodiment
illustrated in Figure 14 the insertion of the curtain 10
into the guide channels is facilitated by the hinge. By
folding down the upper ends of the channels as illustrated
in dotted outline the curtain 10 may easily be fed into the
channel.
With the embodiment illustrated in Figure 13 the
tube 60 may not be detachable and upon impact some of the
fluid in the chamber will be discharged through the
openings 61 so that the torsion balance is upset and the
curtain is wound up.
It has been found as mentioned previously in
experiments that these doors are capable of withstanding
substantial pressures and that they can be subjected to all
manner of abuse which other forms of solid doors have not
been able to withstand. It will be apparent that an
extremely simple solution has been provided where many
other forms have been tried without much success.
It will also be obvious that other forms may be
given and modifications may be made to the embodiments
disclosed in this presesnt app]ication without departing
from the spirit and e~sence of the invention.
