U.S. patent number 3,665,997 [Application Number 05/013,128] was granted by the patent office on 1972-05-30 for adjustable dock seal assembly.
This patent grant is currently assigned to Overhead Door Corporation. Invention is credited to Alfred T. Dietrich, Vernon O. Smith.
United States Patent |
3,665,997 |
Smith , et al. |
May 30, 1972 |
ADJUSTABLE DOCK SEAL ASSEMBLY
Abstract
A dock seal assembly for an opening in a wall, said seal
assembly having a resiliently flexible head seal supported by
upright, parallel track means mounted upon the wall adjacent the
sides of said opening near the upper end thereof. Spring-biased
annular means is supported upon the wall for rotation about a
horizontal axis near the upper end of said opening and is connected
to the head seal by sheet means which covers said upper end of the
opening when the head seal is lowered. The sheet means also serves
to raise the head seal when it is released from an anchored,
lowered position.
Inventors: |
Smith; Vernon O. (Ashley,
OH), Dietrich; Alfred T. (Marion, OH) |
Assignee: |
Overhead Door Corporation
(Dallas, TX)
|
Family
ID: |
21758451 |
Appl.
No.: |
05/013,128 |
Filed: |
February 20, 1970 |
Current U.S.
Class: |
52/173.2; 160/41;
160/265; 160/23.1 |
Current CPC
Class: |
E06B
1/522 (20130101); B65G 69/008 (20130101) |
Current International
Class: |
B65G
69/00 (20060101); E06b 007/00 () |
Field of
Search: |
;160/41,42,133,265,264,23 ;52/173,204 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Taylor; Dennis L.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A seal device for sealing the space between the header of an
opening in the wall of a building and the header of the opening in
the rear of a truck van, comprising:
a pair of elongated track means mounted along the opposite edges of
said opening near the upper end thereof;
cylindrical means rotatably supported adjacent the upper ends of
said track means, said cylindrical means extending between and
substantially perpendicular to said track means;
spring means connected to said cylindrical means and yieldably
resisting rotation thereof in one rotational direction;
elongated seal means extending transversely between said track
means and including an elongated and thick blocklike cushion member
constructed of a resiliently compressible material, said seal means
having a resiliently flexible surface sealingly engageable by the
header of said van;
guide means supported on the opposite ends of said seal means for
moving engagement with said track means, whereby movement of said
seal means is guided lengthwise of said track means;
flexible sheet means affixed along one edge thereof to said
cylindrical means and along an opposite edge thereof to said seal
means; and
said sheet means extending between said track means for covering
the upper end of said opening in said wall means when said seal
means is spaced substantially from said cylindrical means, the
lengthwise axis of said seal means being substantially parallel
with the rotation axis of said cylindrical means.
2. A device according to claim 1, including elongated element means
secured near one to said seal means;
anchor means affixed to one of said track means and spaced
downwardly from said cylindrical means for engagement by said
element means to hold said seal means in a lowered position against
the contrary urging of said spring means.
3. A device according to claim 1, including lock means releasibly
connectible between said seal means and said track means for
holding said seal means in a lowered position against the contrary
urging of said spring means;
wherein said cylindrical means includes shaft means nonrotatably
supported by said track means and tubular means rotatably supported
on said shaft means, said sheet means being secured to said tubular
means; and
wherein said spring means is a spiral spring connected between said
shaft means and said tubular means.
4. A device according to claim 1, including elongated and
substantially parallel side seals adapted to be secured to said
wall on opposite sides of said opening, said side seals having
resiliently flexible surfaces engageable by said truck van and
having recesses in which said track means are located, said side
seals extending from said wall a distance somewhat greater than the
corresponding extension of the seal means.
5. A device according to claim 3, including canopy means adapted to
be secured upon said wall above said tubular means, said canopy
means extending beyond the opposite ends of said tubular means and
projecting away from said wall over and slightly downwardly around
said tubular means.
6. A device according to claim 3, wherein said track means are
vertical, coextensive, channel-shaped and open toward each
other;
wherein a pair of support brackets are rigidly connected to the
upper ends of said track means and project away from said wall,
said brackets having openings through which the opposite ends of
said shaft means are received;
wherein said guide means includes a pair of rollers supported upon
both ends of said seal means for rotation around parallel axes and
disposed within said track means;
bearing means mounted upon said shaft means and rotatably
supporting the opposite ends of said tubular means; and
canopy means secured to said brackets and extending lengthwise
beyond the opposite ends of said tubular means and projecting away
from said wall beyond said tubular means.
7. A device according to claim 6, wherein said shaft means and
canopy means have alignable openings therethrough;
pin means removably receivable through said openings in said shaft
means and canopy means for positively preventing rotation of said
shaft means with respect to said brackets; and
grip means on said shaft means adapted to be engaged for rotating
said shaft means to increase the tension on said spring means when
said pin means is released from said shaft means.
8. A device according to claim 1, including elongated and
substantially parallel side seal devices adapted to be secured to
said wall on opposite sides of said opening, each of said side seal
devices including an elongated and thick block-like cushion member
constructed of a resiliently compressible material and having a
resiliently flexible surface sealingly engageable by the rear ends
of the sidewalls of the truck van.
9. A device according to claim 8, wherein the cushion member of
said seal means and the cushion members of said side seal devices
are constructed of a resilient foam material.
10. A device according to claim 9, wherein said seal means is
provided with an inclined surface on the lower front side thereof
to permit said seal means to be moved downwardly to create a
wedge-like sealing engagement with the rear header of the van after
the rear end of the van has been disposed in sealing engagement
with the side seal devices.
11. A device according to claim 1, wherein said seal means includes
an elongated resiliently compressible stop cushion fixedly secured
to the upper side thereof and extending longitudinally therealong,
said stop cushion being disposed for contacting said cylindrical
means when said seal means is returned to its uppermost position by
said spring means.
12. A door seal outlining the tops and sides of a door opening as
formed in a wall and adapted to seal against the top and side rear
edges of a truck van which backs against the seal, said seal
comprising:
first and second side pad structures adapted to be vertically
disposed adjacent and substantially coextensively along the
opposite sides of said opening, each side pad structure including
an elongated block of a compressible resilient material;
a pair of elongated track means mounted along the opposite sides of
said opening at least adjacent the upper end thereof;
roll means rotatably supported adjacent the upper end of said
opening, said roll means extending substantially perpendicularly
between said pair of elongated track means;
flexible sheet means affixed along one edge thereof to said roll
means and adapted to be rollingly disposed thereon, said sheet
means having a width substantially equal to the width of said
opening;
spring means interconnected to said roll means and yieldably
rotatably urging same in one rotational direction to cause said
sheet means to be rolled onto said roll means; and
a top pad structure disposed below said roll means and fixedly
connected to said flexible sheet means along an opposite edge
thereof, said top pad structure extending substantially
perpendicularly between the first and second side pad structures
and being slidably supported by said pair of track means for
enabling said top pad structure to be vertically moved in the
vicinity of the upper end of said opening, said top pad structure
also including an elongated block of resiliently compressible
material.
13. A door seal according to claim 12, wherein said top pad
structure has tapered surface means provided on the front surface
thereof for permitting said top pad structure to be vertically
displaced downwardly into a wedging and sealing engagement with the
top rear edge of the truck van, and anchor means coacting with said
top pad structure for permitting same to be fixedly secured in a
selected position in opposition to the urging of said spring means.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to an adjustable dock seal and,
more importantly, to a type thereof which has a vertically
adjustable head seal supported on tracks and spring biased toward
the raised position.
Persons familiar with the construction and operation of dock seals,
which close space between the wall of a building and the rear end
of a truck van backed up to an opening in the wall, are well aware
that existing dock seals are not entirely satisfactory. In the
first place, they are difficult to operate, particularly in cold
weather, when they are most needed. That is, the dock seal usually
includes sheet material which extends between the top of the
opening in the wall and the top of the opening in the druck van, in
order to shield the interior of the building and the van from the
weather. This is due to the obvious fact that most trucks have
openings which are of about the same width, but which vary
substantially in height, particularly from the ground. Thus, during
cold, wet or snowy weather, some form of shield must be provided
between the truck and the wall at the upper end of the opening.
According to present practices, the shield material is usually
draped from the upper edge of the wall and there is no means for
storing it or protecting it against the weather when it is not in
use. As a result, this material usually gets wet or freezes stiff
or otherwise becomes difficult to handle when it is needed.
Moreover, the sheet material is exposed to the wind and the eroding
effects of the weather so that it usually wears out far more
quickly than it would if it were protected.
Usually, the head seal of the dock opening has some form of padded,
rigid member which extends across the opening and is connected to
the lower edge of the shielding sheet material. Sometimes this
rigid member is guided in tracks and sometimes it merely hangs
loosely. In any event, it often becomes jammed while it is being
raised or lowered because no simple and effective method has been
provided for producing uniformly vertical movement of all parts
and, as a result, racking of this element usually occurs.
Some attempts have been made to prevent racking of the rigid
truck-engaging head member, but these have involved complicated,
expensive structures which required substantial maintenance and
could only be installed by highly skilled persons.
Accordingly, a primary object of this invention is the provision of
a seal assembly for the edge of a truck dock opening in a wall,
said structure including a head seal supported on the wall for
automatic vertical adjustment and having sheet material that is
automatically retracted or extended when the head seal is raised or
lowered.
A further object of this invention is the provision of a dock seal
assembly, as aforesaid, which can be shipped to the location of
installation in a knocked-down condition and can be easily
assembled and installed on the wall defining the dock opening by
maintenance personnel having average mechanical skills and capable
of following relatively simple installation instructions.
A further object of this invention is the provision of a dock seal
assembly having a head seal and means including a sheet-like,
weather shield connected between the head seal and a spring-biased
roller means whereby the head seal is continuously urged toward a
raised position and said weather shield is substantially completely
protected from the weather when the head seal is in its raised
position.
Other objects and purposes of this invention will become apparent
to persons familiar with this type of equipment upon reading the
following descriptive material and examining the accompanying
drawings, in which:
FIG. 1 is a broken, front-elevational view of a dock seal assembly
embodying the invention and in the installed position.
FIG. 2 is a perspective view of the upper part of said seal
assembly.
FIG. 3 is a sectional view taken along the line III--III in FIG.
1.
FIG. 4 is a sectional view taken along the line IV--IV in FIG. 1
and including a fragment of a truck van.
FIG. 5 is a sectional view taken along the line V--V in FIG. 1.
FIG. 6 is a sectional view taken along the line VI--VI in FIG.
4.
For convenience in description, the terms "upper", "lower", "left",
"right", "front", "rear" and words of similar import will have
reference to the dock seal assembly of the invention as appearing
in FIG. I which is a front view of the assembly. The words "inner",
"outer" and derivatives thereof will have reference to the
geometric center of the dock seal assembly and parts thereof.
SUMMARY OF THE INVENTION
The objects and purposes of the invention, including those set
forth above, have been met by the provision of a pair of side rails
and a canopy which are interconnected and mounted around the upper
end of the dock opening in a wall. Roller means is mounted under
the canopy for rotation around a horizontal axis and is spring
biased in one rotational direction. An elongated head seal has
rollers at its opposite ends for guiding same vertically along and
between the side rails. A flexible sheet-like wheather shield is
connected between the dock head seal and the roller means for
covering the portion of the dock opening above the head seal when
said head seal is in a lowered position. The spring-biased roller
means, acting through the weather shield, counterbalances the head
seal so that it can be easily raised and lowered.
DETAILED CONSTRUCTION
The seal assembly 10 (FIG. 1), is provided to seal the space
between the wall 11 (FIG. 4) defining the opening 12, which is
normally covered by a door 13, and the surfaces which define the
opening 14 in the rear end of a truck van 16 backed up to the wall
11 adjacent said opening 12. For purposes of description, the truck
van 16 may be of any convenient, conventional type mounted upon a
truck chassis (not shown) and having any type of closure member,
such as an upwardly acting door 17, which closes the opening 14
when said van 16 is not being loaded or unloaded.
The seal assembly 10 (FIG. 1) comprises a pair of side seals 18 and
19 and a head seal 22. The side seals 18 and 19 are secured to the
wall 11 by means including the L-shaped brackets 20 and 21,
respectively, which brackets may be anchored upon the wall 11 by
convenient means such as the bolts 26 and 27, respectively.
The head seal 22 is mounted upon and extends between a pair of
upright guide rails 23 and 24 which are supported upon the wall 11
adjacent the right and left sides, respectively, of the opening 11
near the upper end thereof. The rails 23 and 24 are of such length
that the head seal 22 can move vertically along said rails, while
remaining in proper engagement therewith, between raised and
lowered positions which will cover the normal maximum range of the
height of the header 28 (FIG. 4) on the van 16. Normally, this
distance in header height on truck vans differs about 3 feet and,
accordingly, guide rails 23 and 24 (FIG. 1) are preferably designed
to permit 3 feet of vertical movement of the head seal 22. The
width of a truck van 16, or the opening through the rearward end
thereof, is reasonably standardized because of statutory provisions
limiting the maximum width of vehicles which may travel on public
highways. Thus, the seal requirements for openings of many sizes
and shapes can be inventoried with a relatively small number of
parts, the only variations being in width and these are minimized.
Yet, substantially identical installation procedures can be
followed regardless of the changes in size and shape.
The guide rails 23 and 24 are connected near their upper ends to
the opposite ends of a canopy 29, beneath which a flexible weather
curtain 32 is supported by means including a shaft 33.
The guide rail 23, for example, is comprised of an elongated
mounting member 36 having an L-shaped cross section. The flange 37
of the member 36 is parallel with and bears against the front
surface of the wall 11 where it is held by the bolts 40. The
forwardly projecting flange 38 of the angle 36 is spaced from the
adjacent edge of the opening 12 and has an integral return 39 near
its frontward edge both to strengthen such flange and diminish
harmful engagement with such edge.
A channel-shaped roller track 42 (FIG. 3) is rigidly secured, as by
spot welding, to the inner side of the flange 38 adjacent the
rearward edge thereof, hence, adjacent the flange 37. The track 42
opens inwardly to receive rollers 43 and 44 (FIG. 4) mounted on the
rightward end of the head seal 22. The front flange 46 on the track
42 has a rearwardly projecting edge portion 49 which prevents
accidental disengagement of the rollers 43 and 44 from within the
track 42. A bolt 45 (FIG. 4) extends through the flange 38 and the
track 42 so that it will positively prevent accidental
disengagement of the roller 44 from the track 42 through the lower
end thereof.
The upper end of the return 39 (FIG. 4) stops short of the upper
end of the flange 38 so that a mounting plate 47 (FIG. 4) can be
secured to said flange 38 by bolts 48 and project frontwardly of
said flange 38. The rightward end of the shaft 33 extends through
and is supported within appropriate coaxial openings in the flange
38 and mounting plate 47.
The guide rail 24 may be and preferably is a mirror image of the
guide rail 23. Accordingly, the parts of said guide rail 24 having
corresponding parts in the guide rail 23 will have the same
numerical designations in addition to the suffix "A". More
specifically, as shown in FIG. 1, the guide rail 24 has a track 42A
which is secured to the flange 38A of the mounting angle 36A. Thus,
the rollers 50 and 59 (FIG. 6), which are supported upon the left
end of the head seal 22, are received within the track 42A (FIG. 5)
for the purpose of guiding the upward and downward movement of the
head seal.
The rollers 43 and 44 (FIG. 6) are rotatably mounted upon axles 52
and 53, respectively, which in turn are mounted upon the end of the
head seal 22 by the brackets 55 and 56, respectively. The rollers
50 and 51 are mounted upon the other end of the head seal 22 by
axles 52A and 53A and brackets 55A and 56A (FIG. 6) which may be
substantially identical with the axles 52, 53 and the brackets 55,
56, respectively.
The head seal 22 has a backboard 61 fabricated from wood or any
other relatively rigid material to which the brackets 55, 56, and
55A, 56A are rigidly secured by means such as the screws 62 and 62A
(FIG. 6). An elongated and relatively thick block-like cushion of
foamed material 63, such as foamed rubber or resilient foamed
plastic, is mounted upon and secured to the front side of the
backboard 61 by means, such as an adhesive. The lower front edge of
the cushion 63 is beveled at 66 to effect a wedging engagement with
the header 28 of the truck van opening 14. A strip 65 of padding,
such as foamed rubber, is secured to and extends along the upper
edge of the backboard 61 to soften the impact between the head seal
22 and the tube 81 when the head seal is permitted to move upwardly
without restraint in response to urging by the spring 92 in tube
81.
The front, ends, top and bottom of the cushion 63, as well the top,
and sides of the strip 65 and the edges and rear side of backboard
61, are preferably covered with a flexible, durable and
water-repellent material, such as canvas or plastic sheet material
64. The rearward edges of the sheet material are secured to the
backboard 61, as by an adhesive. The head seal 22 preferably
extends up to, but not materially beyond, the side edges of the
opening 12, when said head seal is in the raised position.
The side seal 18 (FIG. 3), for example, has a backboard 67 which is
fabricated from rigid material, such as wood, which is secured to
the wall 11 by any convenient means, such as an adhesive. The side
seal 18 extends above the opening 12 and preferably up to the
canopy 29. The backboard 67 is preferably notched to overlay the
flange 37, to which it may also be secured by an adhesive. An
elongated, substantially rectangular cushion, which may be a
block-like piece of thick foamed material 68, is sculptured so that
it fits around the guide rail 23 and projects sidewardly up to the
edge of the opening 12 in the wall 11. Thus, the inner side of the
foamed material 68 is closely adjacent the rightward end of the
head seal 22.
The front surface of the foamed material 68 and the side and top
surfaces of the foamed material and the backboard 67 are covered by
flexible, durable and water-repellent sheet material 69, such as
canvas or a plastic material, for example. The foamed material 68
may be of any convenient resilient type, such as foamed rubber, and
the sheet material 69 is secured to the side edges of the backboard
67 by means such as adhesive.
The side seal 19 may be, and preferably is, a mirror image of the
side seal 18. Accordingly, the side seal 19 has a backboard 67A
(FIG. 5), a cushion 68A and a sheet material covering 69A. The side
seals 18 and 19 preferably extend from the lower end of the opening
12 to just below the canopy 29.
A mounting plate 47A is secured to the upper end of the guide rail
24 (FIG. 2) and the shaft 33 extends through coaxial openings in
said plate and rail. The canopy 29 has a horizontal section 72 with
an integral upwardly projecting rear flange 73 which is secured to
the upper end of the flange 37 by a bolt 74 and to the upper end of
the flange 37A by the bolt 74A. The canopy 29 has an integral,
downwardly extending flange 76 which is integral with the frontward
edge of the horizontal section 72 and is preferably adjacent the
frontward edges of the mounting plates 47 and 47A. The ends of the
horizontal section 72 preferably project beyond the mounting plates
47 and 47A.
The shaft 33 has a transaxial opening 77 through which a detent pin
78 may be slideably received adjacent the mounting plate 47A. The
detent pin 78, which may be a bolt, also extends through an opening
in the horizontal section 72 of the canopy 29 whereby rotation of
the shaft 33 relative to the mounting plates 47 and 47A is
positively prevented.
The shaft 33 is encircled by and spaced inwardly from a coaxial,
cylindrical tube 81 which extends between and is spaced slightly
from the mounting plates 47 and 47A (FIG. 5). The tube 81 has a
pair of annular end members 82 and 83 which are rigidly secured
within the opposite ends of the tube 81. Bearings 84 and 85 are
disposed within the end members 82 and 83, respectively, for
rotatably supporting the tube 81 upon the shaft 33. A pair of lock
collars 87 and 88 are mounted upon the shaft 33 adjacent the remote
sides of the end members 82 and 83, respectively, to act as bearing
retainers and, at the same time, position the tube 81 upon the
shaft 33.
The end member 83 has an axially inwardly projecting hub 89 of
reduced diameter, upon which one end of the elongated helical
spring 92 is firmly secured. The other or rightward end of the
spring 92 is sleeved upon and firmly secured to a lock collar 93
which in turn is firmly secured to the shaft 33 by means including
the set screw 94.
Accordingly, rotation of the tube 81 relative to the shaft 33 is
resiliently and yieldably opposed by the helical spring 92. Another
similar spring may be connected between the end member 82 and the
shaft 33 in a manner similar to that described above with respect
to the spring 92, thereby increasing resistance to relative
rotation between the shaft 33 and the tube 81.
One horizontal edge of the weather curtain 32 is secured to and
extends lengthwise of the tube 81. The other, lower edge of the
curtain 32 is secured to and extends lengthwise of the upper rear
edge of the backboard 61. More specifically, the lower edge 96 of
the curtain 32 is folded upon itself and a relatively stiff,
elongated element, such as the metal strip 95, extends along and
covers the lower edge 96 of said curtain. A plurality of screws 97
are inserted through aligned openings 98 and 99 in the strip 95 and
lower edge 96 after which they are threadedly received into the
backboard 61 (FIG. 4).
The curtain 32 is wound upon the tube 81 so that the tension in the
spring 92 is increased as the head seal 22 is lowered. After
continuous use, it may be necessary to increase the tension of the
spring 92. Moreover, during installation, it may be necessary to
adjust said tension on the spring 92. This is accomplished by means
of the openings 102 and 103 (FIG. 5) in the shaft 33 at the
leftward end thereof. That is, having removed the detent pin 78
from the shaft 33, an elongated instrument, such as a drift pin or
screwdriver (not shown), can be inserted into one or the other of
the openings 102 and 103 after which the shaft is rotated around
its axis to increase the tension of the spring 92. The detent pin
78 is then reinserted through the opening 77.
A chain 104 (FIG. 2) is secured at its lower end to the guide rail
24 near the lower end thereof and at its upper end to a screw eye
105 in the backboard 61 adjacent the guide rail 24. The chain 104
is of sufficient length to remain loose when the head seal 22 is in
its raised position, about as appearing in FIG. 4. When the head
seal 22 is lowered, one of the links in the chain 104 is sleeved
onto the inwardly projecting end of the stop bolt 45A (FIG. 2),
which prevents the spring 92 from raising the head seal 22. The
lower end of the chain is secured to the guide rail 24 by the bolt
45A.
OPERATION
The seal assembly 10 is installed upon a wall 11 by first mounting
one or the other of the guide rails 23 and 24 in an upright
position upon the wall 11 at a prespecified distance from the
adjacent edge of the opening 12 and so that it extends a
prespecified distance above the upper edge of the opening. A
conventional spirit level may be used to position the guide rail
accurately, if it is suspected that the adjacent edge of the
opening is not plumb. The other guide rail is then mounted upon the
wall 11 on the opposite side of the opening 12. However, before
securing said other guide rail to the wall, it is accurately placed
in an upright position at a specified distance from the previously
mounted guide rail. This can be done by means of a measurement or a
spacing gauge furnished with the seal assembly. Also, before
finalizing the anchoring of said other guide rail upon the wall 11,
it will be advantageous to mount the shaft 33 and the tube 81 on
the mounting plates 47 and 47A, with the tube 81 therebetween,
after which the angular relationship between the shaft or the tube
and one or the other of the guide rails is made perpendicular. This
can be done by using a conventional carpenter's square.
Since the seal assembly 10 will have been ordered in terms of a
door opening of a predetermined width, the spacing between the
guide rails 23 and 24 can also be predetermined even though it may
be more economical to furnish the assembly with horizontal elements
which are slightly longer than necessary to close the opening. That
is, it may be economically advantageous to stock head seals 22,
canopies 29, weather curtains 32, shafts 33 and tubes 81 in
standard sizes which vary in increments, such as 3 or 4 inches.
Thus, special handling or special measuring at the location of
installation are not required, other than the width and height of
the opening around which the seal assembly 10 is being
installed.
The head seal 22 may or may not be attached to the weather curtain
32 prior to installation, but the curtain will normally be attached
to the tube 81. However, preferably, all three of these elements
will be connected together when they arrive at the installation
site.
The canopy 29 can now be installed by connecting the flange 73
thereof to the upper ends of the flanges 37 and 37A on the guide
rails 23 and 24. If desired, the flange 73 can also be secured to a
portion of the wall 11 above the opening 12.
The stop bolts 45 and 45A will be installed after the rollers 43,
44 and 50, 51, at the opposite ends of the head seal 22, have been
inserted into the lower ends of the guide rails 23 and 24,
respectively. However, to minimize inconvenience, the detent pin 78
will be removed from the shaft 33 during the installation of the
head seal 22 into the rails 23 and 24. Thereafter, a long
instrument such as a screwdriver or a drift pin is inserted into
the openings 102 or 103 and the shaft 33 is rotated until the head
seal 22 is in its fully raised position, about as shown in FIG. 4,
adjacent the tube 81 upon which the curtain 32 will then be very
nearly completely wound. The detent pin 78 then will be reinserted
through the opening 77 in the shaft 33 whereby a subsequent
lowering of the head seal will be opposed by the spring 92. The
weight of the head seal 22 will probably create some pretensioning
of the spring 92 before the aforesaid rotation of the shaft 33
moves the head seal 22 into its raised position. The chain 104 will
be connected at one end of the head seal 22 and at the other end to
the guide rail 24 by means of the stop bolt 45A, for example.
The side seals 18 and 19 may then be mounted upon the wall 11 by
means including the L-shaped brackets 20 and 21 (FIG. 1) so that
both sides and the top of the opening 12 have padded flexible
sealing elements extending therealong by which the corresponding
edges of a truck van can be sealingly engaged, as appearing in FIG.
4, it being understood that the foam cushions comprising the side
seals 18 and 19 will readily resiliently compress when the rear
edges of the truck van are backed thereagainst. By raising or
lowering the head seal 22, adjustment can be quickly made for the
wide range of different distances between the header of the truck
opening and the ground. Normally, a piece of metal, plywood or the
like is placed across the opening between the bed of the truck and
the threshold of the opening 12, in a conventional manner, so that
no sealing structure is required at the lower end of the opening
12. Variations in the elevations of truck beds are usually within a
relatively small range and, therefore, little or no adjustment is
required at the lower end of the opening. Likewise, the widths of
truck vans are sufficiently standardized that variations therein
pose no problem provided the side seals 18 and 19 are of reasonable
width. Moreover, the most urgent need for a good weather seal
occurs at the top of the opening 12 where rain, snow, sleet and the
like can most easily enter said opening.
Because the tube 81 is spring biased, and because the tension on
the spring 92 increases as the head seal 22 is lowered, it is
necessary to positively hold the head seal 22 in a lowered
position. This is accomplished by means of the chain 104 which is
looped around or hooked by the stop bolt 45A. Thus, when the chain
104 is released from the stop bolt 45A, the spring 92 automatically
retracts the head seal 22 into its raised position. Thus, except
for the relatively brief period when a truck is being loaded or
unloaded at the opening 12, the weather curtain 32 will be rolled
upon the tube 81 where it is protected from the weather by the
canopy 29.
The bevel 66 on the cushion 63 facilitates a firm, wedged and
weather-tight engagement between the head seal 22 and the van
header 28 where the van 16 is moved against the side seals 18 and
19 before the head seal 22 is moved down from its retracted
position, which will occur frequently. The strip 65 will absorb the
shock of impact between the head seal 22 and tube 81 when the chain
104 is disconnected from the bolt 45A and merely released, whereby
the head seal 22 will move upwardly rapidly under the urging of the
spring 92.
Although a particular preferred embodiment of the invention has
been disclosed in detail for illustrative purposes, it will be
recognized that variations or modifications of the disclosed
apparatus, including the rearrangement of parts, lie within the
scope of the present invention.
* * * * *