Note: Descriptions are shown in the official language in which they were submitted.
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ARTICULATING DOOR HINGE SYSTEM AND DOOR ASSEMBLY
Technical Field
This invention relates to door hardware, and more
particularly to hinges which allow a door to articulate outwardly from
a door frame before being allowed to swing open.
Background
Many large, enclosed industrial structures have access
doors along their lengths to allow workers to access the interior of the
structure for monitoring, maintenance and repair purposes. One such
enclosure which has a plurality of doors is a wood veneer dryer, which
dries wood veneers by heat. The doors in a veneer dryer allow access
to various portions ofthe machinery, including rollers, contained within
the dryer.
Each of these doors in a veneer dryer requires a seal
sandwiched between the door and the door frame, the seal affixed
either to the door or to the corresponding door frame. Such a seal
prevents air from being drawn into the dryer, thereby reducing the
potential for a fire, and also prevents the hot, acrid air produced within
the dryer from escaping from the dryer into the surrounding environ-
ment. Further, the seals are needed to properly maintain pressure
differentials within portions of the dryer itself. It is thus important to
maintain these seals in very good condition.
There are two significant problems with these seals in
current veneer dryers. First, the doors in most veneer dryers are
hinged to the door frames in a standard manner, ie. by simple hinges
which allow the doors to swing open in a typical fashion. This
swinging action wears the door seals unevenly, and in particular, the
portion of the seal closest to the hinged edge of the door wears
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quickly, as the door is opened and closed, relative to the other
portions of the seal. Given the importance of these seals in a veneer
dryer, the seals require constant monitoring and frequent replacement,
costing the dryer operator money and lost time.
Second, most portions of veneer dryers, which are
generally made of metal, naturally expand significantly when hot, and
contract when cold. The amount of expansion, of course, depends
largely on the temperature reached in the dryer, and the material used
in construction of the dryer. The door of a dryer may expand and
contract at a different rate than the door frame to which it is attached.
This alters the pressure on the seal sandwiched between the door and
the door frame.
An operator may try to compensate for this by trying to
adjust the force exerted by the door against the door frame (ie. the
door's tightness) to try to maintain a constant pressure on the seal
between them. Currently, operators try to accomplish this by adding
or removing shims between the hinges and the door and/or door
frame. This is an inaccurate, time consuming procedure which cannot
be done when the dryer is in operation.
To limit the aforementioned uneven and premature wear
on the door seals, therefore, it would be useful to provide an improved
door hinge system which allows an operator to first move a veneer
dryer door relatively straight out and away from the door frame before
swinging the door open in a typical fashion. This would allow the door
seal to wear relatively evenly, reducing the need for frequent replace-
ment.
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Further, to make it possible to adjust the force exerted by
the door against the door frame (ie. to adjust the pressure on the
seal), it would be helpful to provide associated means for allowing a
door to be tightened or loosened against its frame while it is in a
closed position.
Summary of Invention
The present invention provides a door hinge system for
attaching a door to a door frame. Most broadly, the invention
comprises, in combination, a linkage having a first end pivotally
connected to a door at a first pivot axis and a second end pivotally
connected to the door frame at a second pivot axis; and an arm
pivotally connected at a first end to the linkage at a third pivot axis
further from the door than the plane between said first and second
axes. In this manner, the door can be moved outwardly relative to the
door frame by moving the rod longitudinally towards said linkage, and
then swung open in a normal fashion.
While the linkage can be connected directly to the door,
in a retrofittable version of the invention, the first pivot axis passes
through a first hinge portion attached to the door and the second pivot
axis passes through a second hinge portion attached to the door
frame. The linkage is accordingly connected to both of said hinge
portions.
The arm itself may have a u-shaped bracket pivotally
connected to the linkage and a threaded arm portion threaded into a
block provided in the u-shaped bracket for receiving the threaded arm
portion. A locking nut threaded against the block may secure the
threaded arm portion to the u-shaped bracket. When the arm is fixed
at its second end, shortening it by threading the threaded arm portion
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further into the block pulls against the linkage, tightening the door
against the door frame.
In a further embodiment of the invention, a latch assembly
is provided to the door which, in combination with the aforementioned
hinge system, makes up a door assembly for tightening the door
against the door frame. In this assembly, the arm traverses the door
and is connected at its second end to the latch assembly. The latch
assembly has includes means for moving the arm from a first position
pulling on the linkage to close the door to a second position pushing
on the linkage to open the door. The arm can be shortened to tighten
the door against the door frame (more particularly, against the seal
sandwiched between the door and door frame), when the door is in a
closed position. This can be accomplished by providing the arm with
oppositely-threaded end portions and a central portion threaded onto
each. Turning the central portion draws together, or forces apart, the
ends of the arm.
Brief Description of Drawings
In drawings which illustrate specific embodiments of the
invention, but which should not be construed as restricting the spirit or
scope of the invention in any way:
Figure 1 is a schematic illustration of a veneer dryer,
showing a plurality of access doors along one side thereof;
Figure 2A is a cross-sectional illustration of a typical prior
art doorldoor frame arrangement in a veneer dryer, showing a door
hinged to a door frame in the typical manner;
Figure 2B is an illustration of the door/door frame
arrangement shown in Figure 2, showing the seal caught on the door
as the door is being closed;
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Figure 3A is a cross-sectional illustration of a doorldoor
frame arrangement made in accordance with the preferred embodi-
ment of the articulating door hinge system of the present invention,
with the door in a closed position.
Figure 3B is an illustration of the door/door frame
arrangement shown in Figure 3A, with the door in a first position
opened away from the door frame;
Figure 3C is an illustration of the door/door frame
arrangement shown in Figure 3A, with the door in a second, fully
opened position.
Figure 4 is a broken view of the components of the door
hinge system shown in figure 3A;
Figure 5 is a perspective view of the assembled door
hinge system shown in Figures 3A and 4;
Figure 6 is a broken view of the latch assembly of the door
assembly of the present invention;
Figure 7 is a perspective view of the portion of the door
assembly shown in Figure 6;
Figure 8 is a perspective view of the door assembly of the
present invention; and
Figure 9 is a schematic view of a portion of the cross arm
of the door assembly shown in Figure 8.
Description
The present invention relates primarily to doors used in a
wood veneer dryer of the type shown in Figure 1, although the
invention has application in any situation where a good seal must be
maintained between a door and a door frame. Industrial freezer doors
and smoke ovens are other examples where the invention might be
used. Reference is made hereafter to a veneer dryer only for the sake
of example.
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In a veneer dryer, denoted generally hereafter by the
numeral "100", a plurality of doors 10 is provided along the length
thereof to allow workers to inspect and repair machinery (not shown)
contained within dryer 100.
In a typical dryer 100, doors 10 are simply hinged in the
normal manner to door frames formed within the walls of dryer 100.
As shown in Figure 2A, which illustrates a portion of a prior art
door/door frame arrangement in cross section, door 10 is typically
hinged to door frame 12 by a standard hinge 14 having two hinge
leaves 15a, 15b connected by a hinge pin 13. A seal 22 typically
surrounds the door opening. As mentioned earlier, shims 17 may be
placed between hinge 14 and door 10 or door frame 12 to adjust the
"tightness" of door 10 against door frame 12.
With this arrangement, door 10 opens in the direction of
arrow 16, allowing access into the interior 18 of dryer 100. It will be
seen from Figure 2A that this opening movement causes the backside
of door 10 to move in the direction indicated by arrow 20, which tends
to pinch or crush a portion of seal 22 sandwiched between door 10
and door frame 12. As described earlier, repeated opening of door 10
tends to prematurely wear the portion of seal 22 which is so crushed.
Further, in such prior art system, once door 10 has been
opened, seal 22 typically expands, as shown in Figure 2B. When door
10 is closed again (in the direction of arrow 19), the backside edge of
door 10 tends to "catch" seal 22, which is not desirable.
Figure 3A shows a similar view to Figure 2, but shows the
door hinge system of the present invention, denoted generally
hereafter by the numeral "50".
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The system 50 of the present invention also has, in a
preferred embodiment, a door 10 and a door frame 12 enclosing,
together with the other outer portions of dryer 100, the interior 18 of
dryer 100. Again, a seal 22 is sandwiched between door 10 and door
frame 12 to prevent gases from entering, or escaping from, dryer 100.
System 50 also further has a hinge connecting door 10 to
door frame 12. As shown in Figures 3A-5, however, in the present
system door 10 is attached to door frame 12 by a linkage 24.
Specifically, linkage 24 has a first end 26 pivotally connected to door
10 at a first pivot axis 26a and a second end 28 pivotally connected to
door frame 12 at a second pivot axis 28a, conveniently with pins 29
(Figure 4), as shown. Pins 29 can be held in place in any convenient
manner. In this arrangement, door 10 can pivot about axis 26a,
relative to linkage 24, and the door/linkage combination can pivot
about axis 28a, relative to door frame 12.
Apart from ends 26, 28, linkage 24 also has a third portion
30 (Figure 4) serving as a third pivot axis 30a to which is further
pivotally connected one end of an arm 32, also with a pin 29. As
shown in detail in Figure 4, in one embodiment of the invention, arm
32 has a u-shaped bracket 90 on its end, the middle portion of bracket
90 having a block 92 machined to accept the threaded end 80 of a
rod. The significance of this arrangement is described in greater detail
below.
It will be appreciated, as shown in Figures 3A-3C, that
when pivot axis 30a occupies a space further outward of the door than
the plane occupied by both the first and second axes, 26a, 28a,
moving arm 32 along its longitudinal axis in the direction of arrow 34
(shown in Figure 3A) pushes against linkage 24 at axis 30a. With
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enough force, this causes the doorllinkage combination pivoted to
door frame 12 at pivot axis 28a to pivot about that axis in the direction
of arrow 36 (clockwise, in the illustration of Figure 3A).
This action draws door 10 relatively straight out and away
from door frame 12 (ie. in the direction of arrow 38), so that its face is
roughly parallel, but away from, the wall of dryer 100, as shown in
Figure 3B. It will be appreciated that door 10 pivots slightly counter-
clockwise about pivot axis 26a when this occurs. It will also be
recognized that this action, as opposed to the swinging action of the
typical door shown in Figure 2, avoids the crushing of seal 22 by door
10.
After door 10 has been moved out and away from door
frame 12 as described (by a distance dependent upon the relative size
of the door, but in a veneer dryer by about 1 inch), door 10 may then
be swung open in a traditional manner about axis 28a, as shown in
Figure 3C, allowing access to the interior of dryer 100.
Door 10 may be closed in an opposite manner. Namely,
when door 10 is open, it may be swung closed in a normal manner
until its face is roughly parallel with the wall of dryer 100 (Figure 3B).
Door 10 is then pushed straight back towards door frame 12. Pulling
on arm 32 opposite to the direction shown by arrow 34 (Figure 3A)
causes door 10 to be cinched tightly against door frame 12.
In the embodiment shown in Figures 3A-5, separate hinge
portions 40, 42, each having bolt holes 41, are provided for system 50
to allow the system to be retrofitted onto an existing door by bolts 43.
There is no reason, however, that linkage 24 could not be connected
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directly between flanges formed integrally on both door 10 and door
frame 12.
Further, while the previous discussion describes axes 26a
and 28a as occupying the "ends" of linkage 24, this is only for the
ease of discussion; the invention encompasses linkages having any
two such axes in combination with a third, whether or not they are at
the ends of the linkages.
In a further embodiment of the invention, a door assembly
is provided wherein the arm 32 of the hinge system 50 described
above is attached at its opposite end to a latch assembly 60 which
allows door 10 to be latched into a closed position. This door
assembly is shown in Figure 8. While a variety of latch assemblies
might be contemplated, in one embodiment of the invention the latch
assembly 60, as shown in detail in Figures 6 and 7, comprises a door
portion 62 attached to door 10 and a door frame portion 64 attached
to door frame 12.
In this particular embodiment of the invention, door portion
62 comprises a mounting plate 66 (Figure 6) having a pair of flanges
67a, 67b, extending outwardly therefrom. Arm 32 is connected to door
portion 62 of latch assembly 60 with a pin 69 passing through arm 32
and through flanges 67a and 67b. Pin 69 also passes through a hole
65 bored through an arm of an eccentric cam 68 positioned between
flanges 67a and 67b. Again, as described-earlier, arm 32 conve-
niently has a u-shaped bracket 90 on its end, the middle portion of
bracket 90 having a block 92 machined to accept a threaded end 80
of a rod. Arm 32 may also have a locking nut 94 which may be
threadably abutted against block 92 to secure the end of arm 32 to u-
shaped bracket 90.
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Each offlanges 67a, 67b has a curved channel 70 formed
therethrough, allowing arm 32 leeway for movement between a first
position (as shown in Figure 7) wherein arm 32 is drawn close to door
frame portion 64 along channel 70, and a second position wherein
arm 32 is pushed away from frame portion 64 at the opposite end of
channel 70. Pin 69 and arm 32 are forced to follow cam 68 as cam 68
is turned.
Cam 68 may be turned by any suitable means. A vertical
bar 72 passing fixedly through cam 68 serves to form such turning
means in one embodiment of the invention, although other turning
means are contemplated. Bar 72 can be turned by hand, or can itself
be attached to a handle or a more complicated arrangement to allow
an operator to turn bar 72.
Bar 72 may be fixed to cam 68 by any suitable means, but
in the embodiment shown herein is attached by a key stock 96 (Figure
6) which occupies a key channel 98 formed within both bar 72 and
cam 68. Adhesive could also be used.
(twill thus be appreciated that when bar 72 is turned in the
direction shown by arrow 73 in Figure 7, this forces cam 68, and
accordingly, pin 69 and arm 32 into the first, "closed" position,
described above. In this position, arm 32 pulls door 10 tight against
door frame 12. When arm 32 is pushed into an "open" position,
however, by turning bar 72 in the direction shown by arrow 74 in
Figure 7, cam 68 forces pin 69 and arm 32 along channel 70 away
from door frame portion 64 of latch assembly 60, and arm 32 is forced
towards hinge system 50. As described in detail earlier, this moves
door 10 away from door frame 12. In this manner, door 10 can be
opened and closed by turning bar 72.
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Door 10 can be latched to door frame 12 by adding a tab
75 to cam 68 which catches door frame portion 64 of latch assembly
60 when cam 68 is in the first, "closed" position, with arm 32 pulled
towards door frame portion 64.
Another aspect of the invention which is of interest is that
the length of arm 32 may be made adjustable. Figure 9 shows a
version of arm 32 having two oppositely-threaded end portions 80, 82,
and a central portion 84 threaded onto each of them. Arm 32 may be
lengthened or shortened by turning central portion 84. A hexagonal
nut 85, shown in detail in Figure 9, may be tack welded onto central
portion 84 of arm 32, and may conveniently assist in turning central
portion 84 with a wrench.
The main significance of the ability to lengthen and
shorten arm 32 lies in the fact that the ends of arm 32 are also
threadably attached to hinge system 50 and lock assembly 60. When
fixed at these points by locking nuts 94, shortening arm 32 by turning
central portion 84 causes linkage 24 to be pulled upon by arm 32.
Lengthening arm 32 in the opposite manner causes linkage 24 to be
pushed upon by arm 32. When door 10 is closed, shortening arm 32
will cinch door 10 closer into door frame 12, since arm 32 will then pull
more tightly on linkage 24. If door 10 is too tightly pulled against door
frame 12 when closed, it can be loosened by lengthening arm 32. In
this manner, the tightness of door 10 against door frame 12, and
hence the pressure on seal 22, can be adjusted, even when dryer 100
is in operation.
As will be apparent to those skilled in the art in the light of
the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from the
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spirit or scope thereof. For example, most doors will typically have
more than one hinge. In one embodiment of the present invention, the
door assembly provides two or more hinges systems, and associated
latch assemblies. Bar 72 may be used to connect all latch assembles.
Accordingly, the scope of the invention is to be construed
in accordance with the substance defined by the following claims.
