U.S. patent number 3,628,289 [Application Number 05/040,087] was granted by the patent office on 1971-12-21 for sliding door construction.
This patent grant is currently assigned to Beverage Air Company. Invention is credited to Herman L. Buffington, Robert M. Stribling.
United States Patent |
3,628,289 |
Buffington , et al. |
December 21, 1971 |
SLIDING DOOR CONSTRUCTION
Abstract
A refrigerator door unit received in an opening in a
refrigerator wall and adapted for horizontal movement therein to
provide access to a refrigerator compartment. The door system
comprises a unit frame and two parallel doors mounted for
horizontal movement therein. The system is unique, in that, a
complete thermal barrier is provided across the access opening.
Such a barrier is accomplished by thermally insulated doors
equipped with means to seal the space between the doors and by the
unit frame which exposes no conductive path between the
refrigerated interior of the compartment and the ambient outside
air.
Inventors: |
Buffington; Herman L.
(Spartanburg, SC), Stribling; Robert M. (Spartanburg,
SC) |
Assignee: |
Beverage Air Company
(Spartanburg, SC)
|
Family
ID: |
21909020 |
Appl.
No.: |
05/040,087 |
Filed: |
May 25, 1970 |
Current U.S.
Class: |
49/409;
49/504 |
Current CPC
Class: |
F25D
23/021 (20130101); E05D 15/0652 (20130101); E06B
3/4609 (20130101); A47F 3/043 (20130101); E05Y
2900/132 (20130101); E05Y 2900/31 (20130101) |
Current International
Class: |
A47F
3/04 (20060101); F25D 23/02 (20060101); E05D
15/06 (20060101); E06B 3/46 (20060101); E06B
3/32 (20060101); E05d 013/02 () |
Field of
Search: |
;49/386,425,421,DIG.1,504,505,487,501,404 ;52/211,212 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Downey; Kenneth
Claims
What is claimed is:
1. A refrigerator door unit received in an opening in a
double-panel refrigerator wall and adapted for movement for
providing access to a refrigerator compartment comprising: a unit
frame positioned in said wall and removably secured thereto, said
unit frame including a low thermal conductive member, said member
including an elongated base portion, an L-shaped protrusion carried
adjacent one end of said base portion defining a slot, one panel of
said refrigerator wall having a planar portion extending into said
slot and abutting against said L-shaped protrusion, a U-shaped
protrusion having a leg terminating short of said base portion and
facing said other end of said base portion, another panel of said
refrigerator wall having a flange portion adjacent an edge
extending between said leg of said U-shaped protrusion and said
base portion, said member having spaced protrusions on the opposite
side of said base portion from said L-shaped and U-shaped
protrusions defining slots, a pair of thermally insulated doors
mounted in said slots for horizontal movement, and said doors being
provided with a protuberance carried between said doors having low
thermal conductance properties providing a thermal barrier between
said doors.
2. The refrigerator door unit set forth in claim 1 further
comprising: a pair of sealing gaskets carried in said slots between
said base portion and an edge of said insulated doors, and each of
said sealing gaskets having two spaced deformable door contact
members defining a space therebetween for defining a thermal seal
between said base portions and said doors.
3. The refrigerator door unit as defined in claim 1, wherein the
unit frame comprises two vertical sections, a lower horizontal
section and an upper section area where said doors are suspended on
rollers, said vertical and horizontal sections including said low
thermal conductive member, and said upper area has depending
therefrom and in engagement with each door, a thermal seal.
Description
BACKGROUND OF THE INVENTION
The technological development of the refrigeration arts has
progressed steadily and numerous innovations have been conceived
insofar as door structure, door hinge systems and the like are
concerned. Likewise, the art relevant to sliding doors has
progressed. As with other developments, the ultimate objective is
to provide cheaper and more efficient equipment. In this regard,
the advent of convenience stores and the like has brought about a
tremendous surge in sales of cooler and freezer units utilizing
door systems that permit visual observation of goods displayed
therein and subsequent self-service selection by the consumer. The
doors on these various units are thus subjected to a vast amount of
use. As such, the refrigeration efficiency of the unit must be such
that even under continuous use, the products displayed therein will
remain at proper temperatures. Moreover, continued use by the
customer or consumer invariably causes damage of varying degrees to
the doors. The doors must thus be suitably designed to withstand as
much abuse as possible and must be suitable for quick and easy
installation and removal.
The operating efficiency of the refrigerator or freezer unit is of
paramount importance. Conventional door systems presently being
utilized in these environments possess conductive paths
therethrough, between the refrigerated interior of the unit and
ambient outside air. These thermal leaks cause condensation and/or
fogging on the doors. In the event of fogging, where a door
utilizing a transparent center panel is in use, the customer cannot
visually inspect the goods through the door. Consequently the
customer must open the door to inspect the goods and thereby expose
the goods to warmer ambient air which of course must be then cooled
to retain the goods at the proper temperature. The operating
efficiency of the unit is thus reduced. Where condensation appears
on the doors, the droplets continue to form until large enough to
run down or drop off the doors onto the floor. The water
surrounding the unit is thus unsightly and a safety hazard and must
be removed by store personnel.
The construction of the refrigerator door, per se, is not a feature
of this invention, but it is covered in our copending application,
Ser. No. 40,204, filed concurrently herewith and entitled
Refrigerator Door Structure. Such a door is, however, described
herein and is claimed herein in the present environment in
conjunction with the unit frame.
A further disadvantage of sliding doors presently in use and
described in the prior art is the ability of the door to reclose.
To ensure proper sealing engagement between the doors and the unit
frame, a bias means is necessary to hold the door against the
frame. Such means could be provided in one or more ways. First, the
individual channel in which the door rides or the door-supporting
trackway must be sloped in the direction of closing whereby once
opened and released the door would return to a closed position by
gravity. A second and probably better system would be the
utilization of a spring means on the door which is lengthened
during opening of the door and once the door is released seeks its
original state, whereby the door is returned to the closed
position. Inasmuch as doors of this type are subject to great and
continued use, the spring means becomes less effective due to a
stretching or permanent elongation of the spring.
The door system of the present invention has incorporated therewith
improvements that overcome the above-described problems and
disadvantages. Moreover, while the patented prior art does contain
teachings analogous to the instant system, as exemplified by U.S.
Pat. No. 3,177,989 to Di Chiaro; U.S. Pat. No. 3,418,755 to Di
Chiaro; and U.S. Pat. No. 3,466,801 to Bohn, none of these patents
individually or collectively teach or suggest the improved sliding
door system of the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved
sliding door system for a refrigerator unit.
Another object of the present invention is to provide an improved
refrigerator door system that provides a complete thermal break
against thermal conductance from the interior of a refrigerated
compartment to the ambient outside air.
Still further, another object of the present invention is to
provide an improved refrigerator door system having automatic
closing means associated therewith.
Generally speaking, the refrigerator door unit of the present
invention is received in an opening in a refrigerator wall and
adapted for horizontal movement therein to provide access to a
refrigerator compartment, said door unit comprising a unit frame
positioned in said opening in said wall and removably secured
thereto, said unit frame comprising an inner rigid member having a
low thermal conductance property and an outer rigid member snap
fitted thereto; and two thermally insulated doors mounted within
said opening, said doors being spacially separate and parallel,
each of said doors being provided with a protuberance that extends
across a space between the doors to said other door, said
protuberances having low thermal conductance properties, said doors
and said unit frame cooperating when said doors are in the closed
position to provide a complete and continuous thermal barrier in
said opening between said refrigerator compartment and ambient air
outside said refrigerator unit.
More specifically, the door system of the present invention is
equipped with a unit frame that extends around the periphery of the
entire system. The unit frame is comprised of a rigid inner member
that is manufactured from a material having a low thermal
conductance property, such as a rigid vinyl. The inner rigid member
is frictionally engaged with the refrigerator wall and has snap
fitted thereto an rigid outer member, preferably a metal member.
The outer member snap fits to the inner member and extends beyond
the frame to provide an outer aesthetic border around the unit
frame. In the sense of a horizontally moving door that is suspended
from rollers, the unit frame would comprise two vertical and a
lower horizontal section as previously described. An upper
horizontal section of the frame would likewise be provided with a
thermal break, but the structure of the upper section would differ
from the others to receive the door suspension system. Wheels
mounted to the top of the door would be suspended from a suitable
rail in the upper portion of the frame. If, however, the doors are
supported such that the doors rest in a trackway and are supported
thereon, then the unit frame as described above would comprise two
vertical and two horizontal sections virtually as described with
the doors being mounted therein.
The door of the present invention must likewise be thermally
insulated so as to prevent the existence of conductive paths
therethrough, between ambient outer air and the cooler air within
the refrigerated compartment. Likewise, since two doors are
employed for the horizontal moving environment, it is necessary to
have space between the doors to permit parallel movement of both
doors. This space would normally permit a thermal leak. To obviate
such a leak, the doors of the present invention are each equipped
with protuberances that extend outwardly therefrom and engage the
opposite door whereby a double seal is provided to insulate the
space between the doors.
The automatic closing feature for the doors of the present
invention includes a spring secured at one end to the door and at
an opposite end to the door frame. Opening of the door elongates
the spring and release of the door permits the spring to return to
its original configuration, thus closing the door. In general,
continued opening of these doors stretches the spring means and
some of the elastic memory is lost, whereby proper closing of the
door is not accomplished. The stretched spring must then be
replaced. Accordingly, the present invention includes an
improvement which comprises the presence of a spring adjuster,
adjacent the door frame whereby after the spring has stretched
through continued use, the slack may be taken up by the adjuster to
revitalize the automatic closing means and realize continued proper
closing.
Generally speaking therefore, the overall door system of the
present invention presents a system for use with a refrigerator
unit to, when both doors are closed, provide a complete barrier
against conductance of heat therethrough, whereby condensation on
the frame and the doors, per se, is avoided. In accomplishing this
feat, poor thermal conductance materials are employed in the
construction of the unit frame and the unit frame is produced
without the use of extraneous fastening members. Instead, the
components of the door frame snap fit together and the door frame,
per se, is frictionally engaged with the refrigerator wall.
Additionally, each edge of a door that comes in contact with the
door frame is provided a resilient sealing member such that when
the door is in the closed position an additional seal is provided
around the edges thereof. Moreover, the automatic closing system
for the instant doors alleviates the possibility of the door being
inadvertently left open which would reduce the refrigeration
efficiency of the refrigerator unit. Additionally, the adjustment
means for the automatic closing means ensure a longer effective
life for the spring means being utilized in the automatic closing
means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of the side of a refrigerator
unit having incorporated therewith a door system according to the
teachings of the present invention.
FIG. 2 is a side cross-sectional view of the door system of the
present invention taken along lines II--II of FIG. 1.
FIG. 3 is a top cross-sectional view of the door system of the
present invention taken along lines III--III of FIG. 1.
FIG. 4 is an enlarged cross-sectional view of one section of door
frame as provided by the present invention.
FIG. 5 is a partial blown-up cross section taken from FIG. 2 and
showing the relationship between doors for sealing the air space
between the doors.
FIG. 6 is a cross-sectional view of the outer member of a door
frame according to the teachings of the present invention.
FIG. 7 is a cross-sectional view of a rigid inner strip of a door
frame according to the teachings of the present invention.
FIG. 8 is a top cross-sectional view of a door according to the
teachings of the present invention and showing the automatic
closing means associated therewith.
FIG. 9 is a plan view of the adjustment member for the automatic
closing means of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the figures, specific embodiments of the present
invention will now be described.
FIG. 1 is a cutaway of a portion of a refrigerator unit showing the
sliding door environment. FIG. 1 thus shown a portion of a front
wall defined by two panels 10 and 10 of a refrigerator unit having
an opening therein. The opening is filled with a unit frame
generally indicated as 12 and two doors generally indicated as 20
mounted for horizontal movement therein. Opening of either door 20
will thus provide access to a refrigerated compartment within the
refrigerator unit. Such a compartment may be provided with a
plurality of horizontally disposed shelves (not shown) on which
items are displayed for purchase.
The unit frame 12 is comprised of two vertical sections 14 and 16,
a lower horizontal section 18 and an upper horizontal section 19.
Historically, the sections used to make up the unit frame are
metallic sections that are joined together by screws, bolts or the
like, and little if any effort has been directed to the provision
of a thermally insulated unit frame. The ordinary unit frame thus
provides a conductive path through which a thermal leak occurs that
causes condensation on the unit and also reduces the refrigeration
efficiency of the unit.
The doors utilized in the sliding door system of the present
invention are generally mounted in one of two ways. The doors may
be suspended from rollers on trackways above the unit frame or the
doors may be supported on rollers at the bottom of the door that
are received in a recess in the bottom of the door. The particular
means for mounting the doors within the present door system are
not, however, crucial to the present invention. Accordingly, only
the overhead roller support mounting means is illustrated.
Doors 20 as shown in FIG. 1 comprise a central panel 22 that is
held and supported by a suitable door frame 24. Suitable handles 26
permit ease of opening and closing of doors 20.
Whereas different mounting means for doors 20 were discussed above,
the unit frame 12 will naturally vary according to the particular
mounting scheme. For instance, for an overhead suspension system as
is illustrated in FIG. 2, the two vertical sections and the lower
horizontal section of the unit frame 12 would be of same
construction while the overhead horizontal section would be
modified to accept the trackways and roller systems for supporting
the doors. On the other hand, for a mounting scheme where the doors
are supported by rollers in the bottom of the door, the two
vertical sections of unit frame 12 and the upper horizontal section
of unit frame 12 would be of same construction while the bottom
horizontal section would be modified to accept the door support
system. In any situation, however, the teachings of the present
invention may be utilized to modify the particular sections of the
unit frame so as to achieve the complete thermal break that
separates the refrigerated compartment from the ambient air
surrounding the refrigerator unit.
FIG. 2 shows a side cross-sectional view of two doors mounted for
horizontal movement according to the teachings of the present
invention. In FIG. 2, the length of the doors has been cut so as to
reduce the size of the figure and add to the ease of understanding
of the parts thereof. An opening is produced along front wall 10 of
the refrigerator unit to permit access to a refrigerated
compartment within the unit. A lower horizontal section 18 of the
unit frame 12 is comprised of a rigid inner member 30 having a
rigid outer member 40 snap fitted thereto as may best be seen in
FIGS. 2 and 4. Rigid inner member 30 is produced of a material
having poor thermal conductance properties so as to provide a
thermal break between the refrigerated compartment and the outside
of the unit. Member 30 is comprised of a base 31 having protrusions
32, 33, 34, and 35 extending downwardly therefrom. Protrusion 32 is
a "U"-shaped protrusion having only one leg 32' attached to base
31. The other leg 32" of the U does not reach back to base 31 and
provides a space for insertion of a portion of wall 10. Wall 10
thus is frictionally engaged between base 31 and the short leg 32"
of protrusion 32. Protrusion 33 is "L"-shaped having a leg 33'
extending rearwardly in the direction of the refrigerated
compartment. At the base of leg 33', a slot 33" is provided, the
purpose of which will be immediately described. Protrusion 34
extends downwardly from base 31 and terminates adjacent the upper
edge of slot 33" of protrusion 33. Protrusion 35 likewise extends
downwardly, but in an arcuate manner, the purpose of which will be
immediately explained. A section of internal wall 10' extends
forwardly along inner member 30, and inner member 30 is secured
thereto by protrusions 33, 34, and 35. The forward portion of wall
10' is received within slot 33" of protrusion 33, is engaged by the
terminal end of protrusion 34 and by arcuate protrusion 35. Inner
member 30 of unit frame 12 is thus secured to wall section 10' by a
frictional connection between wall 10' and slot 33'. Moreover, the
arcuate protrusion 35 when engaged by wall section 10' is forced
upwardly, whereby a resilient memory in protrusion 35 causes
protrusion 35 to apply positive pressure to wall 10' to assist in
securing same to inner member 30. Also, the resilience of arcuate
protrusion 35 assures a good seal against wall 10' even if wall 10'
is uneven.
The forward end of inner member 30 is cut down so as to receive
rigid outer member 40 in snap fitting engagement. At the beginning
of the cutaway portion of base 31 is a groove 36 having a shoulder
36' for receiving a portion of outer member 40. At the outermost
end of inner member 30, the cutaway portion of base 31 presents a
shoulder 37 for further engagement with outer member 40. Atop base
31 of inner member 30 are two channel defining members 38 and 39
and between channel defining members 38 and 39 is a slot 41 having
lips 41' extending partially thereacross. A sealing gasket 60 fits
into slot 41 and is held therein by a barbed protrusion 61 which
engages lips 41' of slot 41. Sealing gasket 60 has two deformable
door contact members 62 that define a space 63 therebetween and
flex with the force of door 20 to provide a good thermal seal
against door 20.
Referring specifically to FIG. 4, rigid outer member 40 comprises a
body 42 having a tee 43 at its outer end. Tee 43 has extending
rearwardly thereof locking member 44 which passes between wall 10
(see FIG. 2) and shoulder 37 of inner member 30 and engages the
underside of shoulder 37 in snap fitting relationship. The rear end
of body 42 of outer member 40 is cutaway at 42' and has a
shouldered terminal end 44'. End 44' passes into slot 36 of inner
member 30 and engages shoulder 36' therein to be retained in snap
fitting relationship. The upper portion 43' of tee 43 coacts with
channel defining member 38 to form a door channel therebetween.
Body 42 of outer member 40 on its upper side has a slot 45 which
has lips 45' extending partially thereacross. A further sealing
gasket 60 is held therein by a barbed protrusion 61 and deformable
members 62 are presented for sealing engagement with a door 20.
Referring back to FIG. 2, two doors 20 are shown resting on sealing
gaskets 60. Doors 20 are suspended from rollers 70 by struts 75
which are associated therewith and are also secured in any
convenient manner to the top of door 20. The upper portion of unit
frame 12 when the doors are suspended from rollers thus comprises a
track support 50 that may be any desired material and is secured to
top wall 12 of the refrigerator unit by any suitable means, such as
bolts 14'. Track support 50 has two legs 52 and 54 depending
downwardly therefrom. Legs 52 and 54 have transverse sections 53
and 55 respectively, each of which terminates as beads 56 and 57
which serve as the trackways for the door rollers 70. Additionally,
support leg 54 has a slotted lower end 58 with a slot 59 that
receives a sealing gasket 80.
A rigid strip 90 is positioned between track support 50 and front
wall 10. Strip 90 is manufactured from a material having low
thermal conductance properties and has a leg 91 at an upper end
that extends around track support 50 where it is sandwiched between
track support 50 and upper wall 12. The opposite end 92 of strip 90
terminates as a U-shaped member that extends around an in-turned
portion 10" of wall 10 and engages an outer frame strip 40'. Outer
frame strip 40' has a leg 42" extending rearwardly thereof, said
leg having a lug 42" that is received within a like-shaped
depression in U 92 of strip 90 so as to be securely held
thereby.
Rearwardly of track support 50 is further rigid strip 95 of a
material having low thermal conductance properties. Strip 95 has an
upper end 96 that is secured between track support 50 and upper
wall 12 by bolt 14. Strip 95 fits against track support 50 and
depends downwardly therefrom to form a wall engaging channel 97.
Wall 10' is received in channel 97 so as to produce a solid
connection between strip 95 and wall 10'. The lower end 98 of strip
95 has a slot 99 with lips 99' extending partially thereacross.
Slot 99 receives a barbed protrusion 81 of a sealing gasket 80 that
serves to seal the upper portion of a door 20 against a thermal
leak.
FIG. 3 shows a top cross section of two doors mounted for sliding
movement according to the teachings of the present invention. Thus
a front wall 10 of a refrigerator unit is shown having an access
opening to a refrigerated compartment behind the door system. The
two vertical sections of the unit frame are thus shown to comprise
a rigid inner member 30 in frictional engagement with panels 10 and
10' and a rigid outer member 40 snap fitted to inner member 30.
Door channel defining members 38 and 39 are likewise shown in
conjunction with member 43' of outer member 40 to define the two
parallel channels in which the doors move. Further, on each sealing
end of a particular channel, a sealing gasket 60 is secured to the
inner members 30. It is noted that for the vertical sections of the
unit frame, a sealing gasket 60 is not provided on the end of the
channel where the door 20 does not come into sealing engagement
with the particular section of the unit frame. Instead, a button 65
is secured within the slot that would accept the sealing gasket. An
air space 200 exists between the two doors 20 that are mounted for
parallel movement. In order to provide a complete thermal barrier,
it is thus necessary to seal the area between the doors so as to
insulate air space 200. Such a seal is produced as shown in FIG. 3,
and the features of the doors 20 that afford such a seal will now
be described with reference to FIGS. 5, 6, and 7.
In FIG. 5, a portion of the adjacent ends of the two mounted doors
as displayed in FIG. 3 is shown enlarged. Each door in FIG. 5
comprises a panel 22 which preferably is a transparent multipane
glass unit that affords the proper thermal insulation while
permitting visual inspection of the goods behind the doors. Each
panel 22 is surrounded and held by a door frame generally indicated
as 24. Door frame 24 comprises a rigid outer member 40" which may
be a metallic member and is preferably stainless steel or aluminum.
Outer member 40" assumes a U-shaped configuration having a long leg
42', base 44' and short angularly disposed leg 46. A rigid inner
member 50' of a material having poor thermal conductance properties
is snap fitted to outer member 40" so as to sandwich panel 22
therebetween. Inner member 50' comprises a shoulder 52', an
inwardly protruding barb 54', and a U-shaped end 56 having an inner
leg 57'. Shoulder 52' of member 50' mates with base 44' of outer
member 40" while barbed protrusion 54' engages angularly disposed
leg 46 of member 40" so as to unite members 40" and 50'. Inner leg
57' of U-shaped end 56 resides adjacent one side of panel 22 so as
to hold panel 22 between member 50' and leg 42 of member 40".
Preferably member 50' when constructed possesses a slight curvature
as shown in FIG. 7, such that, when snap fitted onto member 40"
with a panel 22 therebetween, member 50' straightens out while
retaining the memory of the curvature so as to continuously apply a
positive pressure against panel 22.
The door frame generally described above contains no separate
fastening members, and thus since internal member 50' is exposed to
the refrigerated compartment, while member 40" is not, no thermal
conductive path is present through which heat may be lost and by
which condensation may occur insofar as the door, per se, is
concerned. Since, however, as mentioned earlier there is an air
space 200 between the parallel mounted doors 20, it is necessary to
seal this area so as to provide a complete thermal barrier between
the refrigerated compartment and ambient outside air. Referring to
FIGS. 5 and 6, a rigid outer member 40" is shown having a sealing
strip 48 attached thereto. Outer member 40" is provided with a slot
47 having lips 47' extending partially thereacross. Sealing strip
48 possesses a barbed protrusion 48' which passes between lips 47'
of slot 47 and is secured therein. When the two doors 20 are
mounted in parallel relation in the door system of the present
invention, sealing strip 48 extends outwardly from outer member 40"
of the inner door 20 of the system where it engages the inner
member 50' and/or panel 22 of the outer door 20 of the door system.
In so doing, one end of air space 200 is sealed, since sealing
strip 48 is produced from a material having low thermal conductance
properties. Preferably, sealing strip 48 extends across space 200
all the way to the panel 22 of the parallel door 20, whereby
regardless of the position of the two doors 20, sealing strip 48
would always seal one end of air space 200.
FIGS. 5 and 7 show rigid inner member 50' which has adjacent
shoulder 52, an angular protrusion 54. Angular protrusion 54
extends outwardly from member 50" for a distance sufficient to
reach across air space 200 and to engage panel 22 of the inner door
20. As with sealing strip 48, angular protrusion 54 of inner member
50" remains in contact with panel 22 of inner door 20 in any
position so as to seal that particular end of the air space
200.
As mentioned earlier, the doors utilized in the sliding door system
of the present invention have an automatic closing feature. This
feature is best illustrated in FIGS. 2, 8, and 9. FIG. 8 shows a
top cross section of a door 20 positioned within a unit frame 12 of
a door system according to the present invention. Door 20 is shown
suspended from a pair of rollers 70 that ride on a trackway 56.
Each roller 70 is secured to a strut 75 by a suitable pin 76 and
the roller 70, on the end of the door away from the door frame in
the closed position, has attached thereto at member 75 a spring 77
that is preferably a coiled spring. Spring 77 is associated with
wall 10 at an opposite end thereof. Accordingly, if door 20 as
shown in FIG. 8 is moved in the direction of the arrow, spring 77
will expand along with movement of door 20. When, however, door 20
is released, spring 77 will seek its original coiled position and
in so doing will cause door 20 to move in a direction opposite to
the direction of the arrow and to move into sealing engagement with
unit frame 12. Continuous operation of door 20 will normally cause
spring 77 to stretch and hence lose some of its memory. A spring
adjustment bar 100 is thus provided to take up the amount that
spring 77 may have stretched. Adjustment bar 100 has an L-shaped
flange 102 at the end thereof and is secured to wall 10 through
flange 102. Along the length of adjustment bar 100 are a plurality
of angular slots 104. During initial installation of door 20,
spring 77 would be attached to adjustment bar 100 at the first or
the closest slot 104 to spring 77. As use of door 20 continues and
spring 77 begins to stretch, spring 77 may be moved along the
successive slots 104 of adjustment bar 100 to continuously provide
proper tension in spring 77 and thereby increase the useful life
thereof. Adjustment of spring 77 will thus ensure that door 20 will
come to rest in sealing engagement against gasket 60 so as to
provide a complete thermal barrier between the refrigerated
compartment and the ambient air.
For doors supported from underneath for horizontal movement, unit
frame 12 would have like vertical and upper horizontal sections
while the lower horizontal section would be modified. Such
modification to the lower horizontal section would primarily
involve only the provision of a bearing surface on which the door
rollers would ride.
Having particularly described the present invention, one skilled in
the art may readily arrive at modifications and adaptations thereto
without departing from the spirit of the invention. Accordingly,
the scope of the invention should be governed by the claims
appended hereto.
* * * * *