Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
This invention relates to a refrigerator cabinet
construction.
BACKGROUND OF THE INVENTION
A common technique in refrigerator cabinet
construction is to provide a false bottom in a
three-sided refrigerator cabinet shell. An example of
this is disclosed in United States patent 3,707,243. The
outer wrapper has a three-sided structure which has a
false bottom secured in its lower portion. One of the
purposes of the false bottom is to define a compressor
compartment. Additional support members must be secured
to the bottom of the refrigerator to support the
compressor assembly for the re~rigerator located in the
rear compressor compartment. These suppor-ts are formed
of metal, hence requiring the use of elaborate vibration
dampening devices in supporting the compressor on the
metal frame.
Another approach to constructing a refrigerator
cabinet having a three-sided outer shell is disclosed in
Canadian patent 1,001,204. The liner is inserted into
the three-sided wrapper which provides the cabinet sides
and top. The rear panel includes a bottom portlon of
sheet metal which is placed into the wrapper to complete
the cabinet. The combination rear panel and bottom
includes a struck-out portion to accommodate a
compressor. ~dditional metal cross members are required
to traverse the opening to compressor compartment. The
refrigerator compressor is mounted on the cross members
resulting in the same drawbacks as the system of United
States patent 3,707,243.
Another technique of cabinet construction is
disclosed in United States patent 3,948,410. A
wrap-around shell for the cabinet provides the cabinet
sides, top and bottom. The rear panel, which is inserted
into the cabinet, includes a preformed compressor
compartment. A rectangular base member is secured to the
underside of the cabinet to support it~ Foam insulation
is placed beneath the compartment shell and additional
structure members are inserted into the compartment she~l
to support a compressor mounted therein. By having to
place foam under the compressor compartment shell for
support, the compressor is elevated considerably within
the refrigerator cabinet resulting in a reduction in
interior space in the cabine-t. In roll forming the
wrap-around shell arrangement, it is very difficult to
control the alignment to ensure that the ends align at
the corner where they are joined.
The cabinet construction, according to this
invention, eliminates the need for false bottoms in the
cabinet, provides significant economies in assembly and
permits the mounting of a compressor directly on the base
for the cabinet.
SUMMARY OF THE INVENTION
The foam insulated refrigerator cabinet assembly,
according to an aspect of the invention, comprises a
metal outer wrapper which defines the cabinet sides and
top. The outer wrapper is mounted on a molded plastic
base. A rear panel having a compressor compartment shell
associated with its lower portion is mounted on the rear
of the wrapper. A cablnet liner is mounted on the front
o~ the wrapper. ~he compressor compartment shell has a
bottom perimeter which contacts the molded base.
Each cabinet side has a lower marginal edge with
means for connection to the base. I'he cabinet sides and
top have ~ront and rear peripheral marginal edges with
means for foxming a foam tight seal with the liner and
rear panel peripheral edges. A foam tight seal is also
formed between the base and the bottom perimeter of -the
compartment shell so as to define a compressor
compartment directly above the base. The base has an
integral support portion within the compartment for
supporting a compressor. The base has means for forming
a foam tight seal with and connection to the liner and
any remaining portion of the rear panel to either side of
the compressor compartment. A cavity is defined between
~he assembly components oE the wrapper, base, rear panel,
compartment shell and liner. The cavity is filled with
a~
an expanded ~oam insulation which becomes rigid to
complete the securement of the assembly components.
The method, according to an aspect of this
inven~ion ~or constructing a foam insulated re~rigerator
cabine~, comprises roll forming a length of metal sheet
to form U-shaped channel portions along the front and
rear edges of the wrapper and bending the metal sheet to
form the wrapper. The rear panel is slid into the
wrapper rear U-shaped channels from the bottom open end
of the wrapper. The wrapper along its bottom edges has
means for co-operating with locator means provided on the
base. The base is posi-~ioned on the wrapper by engaging
the co-operatlng means of the wrapper with the base
locator means and fastening from the underside the base
to the wrapper sides. A front liner may be placed into
the assembly by either sliding the liner into the wrapper
front U-shaped channels from the bottom open end of the
wrapper before the base is applied, or the front liner
may be snapped into the U-shaped channels of the wrappex
front after the base is connected to the wrapper bottom.
The assembled wrapper, liner, rear panel, base and
compartment shell form a foam tight seal about their
junctions. A foam insulation is introduced in-to the
cavity so defined to complete the foam insulated
assembly.
According to another embodiment of the invention,
in a refri~erator cabinet construction, the rear panel
has a cut-out at its bottom which is U-shaped. A molded
plastic compressor compartment shell, which has a
U-shaped opening, is introduced into the corresponding
U-shaped opening of the rear panel. The perimeter of the
compressor compartment shell receives the edges of the
U-shaped cut-out of the rear panel. The shell has a
bottom perimeter which contacts a bottom portion of the
cabinet.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown
in drawings, wherein:
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Figure 1 is a section through a refrigerator
having a cabinet construction according to this
invention;
Figure 2 is a perspective view showing the
assembly of the rear panel to the cabinet wrapper;
Figure 3 is a perspective view showing the
assembly of the front liner and hase assembled to the
unit of Figure 2;
Figure 4 is a perspective view of the upper
surface of the base;
Figure 5 is a perspective view of the underside
of the base;
Figure 6 is a plan view of the cut out metal
sheet prior to roll forming into the three-sided
structure;
Figure 7 is a cut-away view showing in exploded
form the aligning of the cabinet side with a base corner
portion;
Figure 8 is a perspective view showing the
location of a molded plastic compressor compartment
shell; and
Figure 9 is a section through the rear portion of
the assembled reErigerator cabinet with compressor about
to be mounted on the cabinet the base.
DET~ILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The reErigerator cabinet construction, according
to a preferred embodiment of this invention, is shown in
Figure 1. The refrigerator cabinet generally designated
10 consists of a metal wrapper 12 with rear panel 14, and
front liner 16. The rear panel 14 has associated
therewith a compressor compartment shell 1~. A base 20
interconnects the wrapper sides of the refrigerator with
the front liner/ rear panel and compressor compartment
shell. No false bottom is required in this cabinet
assembly. The base 20 provides a compressor support in
the area 22.
The base 20 includes in area 24 a component for
the hinge mounting of cabinet door 26 which covers the
refrigerator portion 28 of the refrigerator. The upper
portion of the cabinet door 26 is hingedly mounted at 30
to the partition 32 which separates the refrigerator
compartment from the freezer compartment 34. The upper
cabinet door 36 is hinge mounted at 30 and at 38. As
schematically shown, the evaporator assembly 40 ls
provided in the freezer compartment. With the cabinet
assembled, a cavity generally designated 42 is defined
between the assembled cabinet components of wrapper, rear
panel and its compressor compartment shell, the front
liner and base. With these components assembled, the
cavity 42 is filled with an expandable insulating
urethane foam according to techniques well understood and
widely used by those skilled in the field of insulating
refrigerator cabinets.
The refrigerator cabinet has a compressor 44
mounted on the compressor support 22 of the base 20 and
condensor coils 46 are mounted on the rear of the
refrigerator for purposes of the heat exchange in the
refrigeration cycle. Because the compressor 44 is
mounted directly on the base 20, the compressor
compartment shell 18 is sufficiently low enough to
provide for a level surface from the jog 48 across upper
surface 50 of the crisper compartment 52 as it rests on
bottom 54 of the liner. This arrangement thereby
increases the usable space within the refrigerator
compared to othe~ cabi.net arrangements.
As shown in Figure 2, the wrapper 16 for the
cabinet assembly 10 has opposing side walls 56 and 58 and
a top 60. The front edge 62 and rear edge 64 of the
wrapper sides and top each have formed therein a U-shaped
channel which is shown in more detail in Figure 7.
The bottom of the sides 56 and 58 include flange
portions 66 and 68 which are provided for purposes of
connection to base 20. The flanges 66 and 68 include
apertures 70 and 72 which cooperate with corresponding
components on the base for purposes of locating -the
wrapper sides on the base. Apertures 71 and 73 are
provided for co~operating with self-tapping screws in
affixing the base to the wrapper sides. Top plates 75
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are stuck with adhesive behind flanges 66 and 68 over
corresponding apertures 71 and 73. The self-tapping
screws, as applied from the base underside, are screwed
onto top plates 75 to secure the base to the flanges.
The rear panel 14 has a U-shaped opening 74 with
radiused corners 77 cut therein to receive the
corresponding U-shaped perimeter of the front of the
compressor compartment shell which is shown in more
detail in ~igure 8. The bottom of the rear panel 14
includes notches 76 and 78 which permit insertion of base
locator components into the respective edge corner
portions of the wrapper sides 56 and 58.
To assemble the refrigerator cabinet, the wrapper
16 is formed from a blank 80 as shown in Figure 6. The
blank 80 is die cut from a length of metal sheet so as to
15 provide the cabinet sides 56, 58 and top 60. The edges
62 and 64 are rolled formed so as to provide the U-shaped
recesses 82 as shown in more detail in Figure 7. Cut
outs 84 and 86 are provided so that when the wrapper 16
is folded, the corners form a miter joint 88 of Figure 7.
A plastic cap 89 of Figure 3 may be inserted between the
spaced edges of the miter joint 88 to provide a finished
corner. The wrapper 16 is folded about lines 90 and 92
to provide the three-sided structure as shown in Figure
2. It is also ~olded about lines 94 and 96 to provide
the laterally extendlng flange portions 66 and 68.
It should be noted that the cut out arrangement
for the wrapper is symmetrical about the centre line.
Because of this symmetry, it is possible to form the
blank from metal sheet which is painted on both sides.
This is an advantage in the refrigerator industry where
at present two colors form the predominant portion of the
market, namely white and almond. Thus, the sheet metal
may be painted white on one side and almond on the other
side and rerolled~ Depending upon the color of the
wrapper required, the sheet may be appropriately unrolled
from the rolled painted stock in the direction which
provides the desired exterior color facing upwardly.
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The cabinet may be assembled in a variety of
ways. According to the embodiment of Figure ~/ the rear
panel is inserted into the wrapper rear peripheral
channel portions through the open bottom of the three-
sided wrapper.
Subsequent to insertion of the rear panel as
shown in Figure 3, the liner 16 with peripheral edge 98
is inserted through the open bottom of the wrapper into
the front edge 62 of the wrapper in -the direction of
10 arrow 100. With the liner in place, the base 20 is
placed onto the flanges 66 and 68 to interconnect the
wrapper sides 56 and 58 with the liner 16 and the rear
panel 14. Locating devices on the base, which will be
discussed with respect to Figure 7, are used to align the
wrapper with the base. Fasteners, as applied from the
underside of the base 20, pass through the base and
flange apertures 71 and 73 into the tap plates 75 to
secure the connection of wrapper to base. In the
assembly of Figure 3, the compressor compartment shell 18
may be placed in the rear panel 14 before the panel is
slid into the wrapper, or optionally as shown in Figure
8, the compressor compartment shell can be snap fitted
into the U-shaped opening 74 after the assembly of Figure
3.
Another approach to assembling the cabinet is to
insert the rear panel into the wrapper and affix the base
with compartment shell to the wrapper bottom. The liner
is then snap fitted into the channels in the front of the
wrapper and base to complete the assembly.
The base 20 for the cabinet construction is
molded from a rigid plastic. This facilitates the
incorporation in -the base of the many structural features
which interact with the cabinet wrapper, liner and rear
panel and compressor compartment shell to form a complete
assembly, while at the same time allowing mounting of the
compressor directly onto the base. As shown in Figure 4,
the base 20 includes upstanding pins 100 and 102 which
are in register with the corresponding apertures 70 and
72 in flanges 66 and 68 of the wrapper sides 56 and 58.
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As shown in Figure 7, pin 102 is aligned with aperture 72
where their relationship is such that when the pin 102 is
inserted in aperture 72, the cabinet flange is properly
aligned with that side 104 of the cabinet base. The same
relationship ~pplies for pins 100 and apertures 70 in
locating and mounting the wrapper flange 66 on the other
side 106 of the cabinet base.
Upstanding tabs 108 and 110 are provided at the
front and rear portions oE the base of Figure 4. The
10 tabs 108 and 110 extend into the U-shaped channel 82 of
the corresponding front and rear peripheral edge portions
62 and 6~ of the wrapper. As shown in Figure 7,
upstanding tab 110 is inserted in the direction of arrow
112 into the U-shaped recess 82 to further enhance the
alignment of the cabinet wrapper with the base 20. The
flange 68 extends short of the U-shaped recess 82 to
allow the upstanding tab 110 to pass beyond the flange 68
and into the U-shaped recess 82 of the respective edge 62
of the wrapper. Apertures 112 and 11~ are provided on
the sides 104 and 106 of the base of Figure 4. These
apertures are aligned with apertures 71 and 73 in the
flanges 66 and 68 to permit insertion of screws from the
underside of the base. The screws are self tapping and
engage the tap plates behind aligned aperture 73 as shown
in Figure 7. This secures the base to the wrapper sides
to form a foam tight seal between the flanges 66 and 68
and the base upper surface 118. The base upper surface
118 also includes an integral raised U-shaped channel 120
into which the bottom of the liner periphery 98 is
inserted. This relationship is shown more clearly in
Figure 1 where the liner periphery 98 is received by the
raised U-shaped channel 120 to form a foam ti~ht seal
along the lower edge of the liner and base portion.
The upper surface 118 includes a ridge 122 which
in combination with the bottom perimeter of the
compressor compartment shell 18 forms a foam tight seal
between the shell and the base upper surface 118. With
reference to Figure 9, the detail of the ridge 122 is
shown in relation to the bottom perimeter 124 of the
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shell 18. The shell bottom has depending barbs 128 which
are snap fitted in corresponding apertures 130 in the
base. The shell vertical wall 132 abuts the inner
surface 134 of -the ridge 122. A flange extends about the
shell bottom perimeter 124 and abuts base surface 118.
The flange 125 acts as a foam seal for the cavity 42.
The front U-shaped perimeter 136 of the compressor
compartment shell includes a U-shaped recess 138 for
receiving the edge of the U-shaped opening 74 of the rear
panel 14. This U-shaped recess 138 is shown as extending
around the entire front perimeter 136 of the compressor
shell 18. This arrangement provides foam tight seals
amongst the shell 18, the base 20 and the rear panel 1~.
The compressor support portion 22 of the base has
a planar upper surface with four spaced-apart bores 140.
Referring to the underside 142 of the base 20, as shown
in Figure 5, the compressor support region 22 includes
additional cross ribbing 144 in the area of each bore
140. This provides the additional support needed to
carrying the weight of the compressor. The underside 142
of the base 20 includes an additional grid work of
reinforcing ribs 144. At the corner areas 146,
additional reinforcing ribs 144 are provided for the
levelling ]egs 148 which are screwed into the apertures
150. The apertures 150 have formed integrally therein a
threaded bore which receives the threaded levelling leg
148 as shown in Figure 3. In addition, pockets 152 are
provided on the underside to receive the roller devices
154 which include a wheel 156 and a mounting plate 158
which is friction fit within the opening 152.
In order to provide for the hinge supports 24, an
extension 156 is provided on the base to extend beyond
the front levelling legs and rollers of the base
arrangement. This extension 156 also includes a
plurality of reinforcing ribs 15S to support the
cantilever mounting of the extension 156 in pro~iding the
smooth continuation of the upper surfacè 11~. In each
corner, additional reinforcing ribs 158 are provided in
the extension to reinforce the component 24 for the hinge
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mounting of the cabinet door. As shown in Figure 1, the
hinge component is an aperture 160 which receives the
depending pin 162 of the door hinge component, as shown
in Figure 1, so that the door may swing freely as
supported by the extension 156 of the base assembly. The
front wall 164 of this extension is approximately flush
with the exterior surface 166 of the cabinet door 2~ to
provide a kick panel beneath the door and an attractive
finished appearance across the base of the refrigerator
front.
Returning to the compressor mounting of Figure 9,
the compressor 44 has a mounting plate 168 through which
threaded bolts 170 extend. Mounting bushings 172 and 174
are provided on top of the support portion 22 of the base
to dampen vibration generated by the compressor motor and
reduce the transmission of sound through the plastic base
to the refrigerator cabinet. By use of the plastic baser
a ~uieter refrigerator operation is achieved because the
plastic base in combination with the sound dampening
bushings 172 and 174 deaden the sound. In addition,
having the compressor compartment shell 132 formed of
plastic, a further attenuation of the sound generated by
the compressor motor is achieved. The bolts 170 may be
~ormed of Nylon (trademark) or other plastic so as to
engage the threaded apertures 140 of the compressor
support 22 and provide a further dampening o~ the noise
generated by the compressor motor. In addition, this
mounting arrangement is all of plastic and rubber which
reduces the likelihood of any moisture causing rusting
and corrosion in the area of the compressor mount.
To reduce the volume between the base 20 and the
bottom 54 of the liner, the base 20 includes in its upper
surface a raised portion 176 which opposes the lower
portion 54 in the liner to provide a narrowed portion 178
in the cavity ~2. This reduces the amount of foam
insulation required in this area and also improves on the
flow characteristics of the unset foam to ensure that all
portions of the cavity in this area are properly filled
with foam insulation to the desired density. The raised
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portion 176 may include reinforcing ribs 180 to
strengthen to a marginal extent ~he raised portion 176.
As shown in Figure 9, the cavity 42 defined between the
liner and other cabinet components is filled with the
foam insulation 182. As is appreciated, a release film
may be applied to the inner surface of the liner 16 such
that when the foam 182 sets, it does not adhere to the
inner surface of the liner 16 so that the liner may
expand and contract due to varying temperatures within
the refrigerator without placing any undue strain on the
liner and thereby avoid stress cracks in the liner.
It is appreciated that the compressor compartment
shell 18, as shown in Figure 8, may be used with
refrigerator cabinets having other than plastic base
portions 22. The plastic compartment shell may be used
with other styles of refrigerator cabinet designs, where
it is desirable to include the advantages of the molded
shell of plastic which has noise attenuation and
electrical shock prevention characteristics. In
addition, an electrical connection box 139 of Figure 8
for the electrical wiring leading to the compressor motor
may be integrally molded on the compartment shell to
improve on an electrical shock proof system.
Further features of the plastic base, include
forming about the compressor support portion 22 a
recessed well 184 of Figure 4 into which condensate from
within the refrigerator may be transferred. The heat
from the operating compressor can then be used to
evaporate the condensate from the well defined about the
compressor support 22. Ventilation slits 184 may be
provided beneath the compressor to allow cooling air to
pass upwardly over the compressor~
It is also appreciated that in the use of a
plastic base and the avoidance o~ metal components used
in mounting the compressor within the compressor
compartment, corrosion problems are eliminated. This
also alleviates previous problems with metal bases which
had contact with the floor and would leave rust spots on
the floor. In addition, the plastic acts as a heat
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insulator to reduce heat transfer to flooring beneath the
refrigerator where, in the past, such heat can be
sufficient to cause warpage and damage to the flooring.
The molding of the plastic base may be
accomplished by injection molding techniques where a
preferred form of plastic used is polyvinyl chloride.
The plastics may be reinforced with glass fibres or
sections of metal may be molded into the base in the
injection molding process. For example, with the corner
support hinge component 24 at each corner of the
cantilevered extension 156 of the base, metal plates may
be integrally molded within these portions to support the
door hinges and prevent cold flow causing a warpage of
the door support over time. In addition, a metal plate
could also be integrally molded with the compressor
support 22. These metal plate inserts are completely
surrounded and encapsulated by molded plastic.
It is apparent from this discussion of the
refrigerator cabinet design according to this invention,
that there is a substantial reduc~ion in the number of
parts required to assemble the refrigerator cabin~t.
Compared to well known designs involving a false bottom,
there is approximately a 50~ reduction in parts required
and thus a significant reduction in assembly and
sub-assembly times and the elimination of several
fabrication steps. This arrangement readily lends itself
to assembly by robotics which can substantially increase
the rate of production of the refrigerator. By the use
of foam insulation which rigidifies when the cavity 42 is
filled with foam, the entire structure takes on a rigid
configuration. In the foaming technique, all of the
interconnections of the rear panels and liners wi-th the
hU-shaped front and rear recessed edges form a foam tight
seal such that when the foam is introduced in~o the
cavity and rigidifies, the connections are permanently
secured.
The molding of the refrigerator base also lends
itself to the use of various colored plastics so as to
color coordinate the base with the refrigerator cabinet
color as may be required in the more expensive lines of
refrigerators. It is appreciated that depending upon the
size of the refrigerator, different size bases may be
required. However, usually with a judicial selection of
base sizes, a number of different volumes for the
refrigerators may be provided with a minimum number of
different base sizes required.
Although various preferred embodiments of the
invention have been described herein in detail, it will
be understood by those skilled in the art that variations
may be made thereto without departing from the spirit of
the invention or the scope o~ the appended claims.
