Note: Descriptions are shown in the official language in which they were submitted.
PATENT Docket 9D-MA-17265 - Jenkins et al
BACKGROUNp oF THE ~NVENTION
In the construction of a household refrigerator it is often
desirable to provide a partition within the refr19erator for separating
the refrigerator tnto a freezer compartment and a fresh food compartment.
It is further desirable to have the partition construct~d in such a
manner that there is a mullion bar across the front of the partition and
secured to the cabinet outer case at each side to rigidify the cabinet,
maint~i" ~ urrect width of the cabinet and afFord i pleasing
appearanco. The freezer and fresh food compartm~nrs are in many cases
closed by separate access doors whtch are hingedly attached to the
cabinet outer case. For the pleasing appearance of the mullion bar and
the proper f;t of the doors for the freezer and fresh food compartments
it is important that the width of the refrigerator cabinet be maintained
and that the loads on the door do not produce excessive deflection of the
cabinet, and further that the door openings are square and more
tmportantly remain square under normal loads iwposed on the cabinet. It
has been common ~o utilize a mullion bar and a bottom front rail between
the stde walls of the cabtnet to help rigidtfy the cabtnet.
Generally household refrigerators normal1y employ a sheet metal
outer casing and an tnner liner with a res1n foam insulation medium
tnterposed therebetween. The foam or polyurethlne compositions in
ltqutd/gas form are introduced into the space between the outer casing
and tnner liner, expand throughout the space and then are solidified by
curtng. In practice this solid foam which inherently adheres to both the
outer case and inner liner adds rigidity to the cabinet structure. In
some instances due to uneven floors or the force placed on the cabinet by
wetght of the doors the cablnet wtll deflect. Thts deflect10n tn some
tnstances will cause a misalignment of the door where1n proper closure of
the cabtnet ts tmpossiblq Tt has been determined that when 2 cabtnet
deflects due to its be~ng posittoned on an uneven floor or excesstve door
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PATENT - Docket 9D-MA-17265 - Jenklns et al
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loadlng the foam insulatiDn between the nuter cas& and llner tends to
creep. The ~oam insulation will set in its deflected positlon thereby
causing the cabinet to form a permanent parallelogram as the cabinet
conforms to the floor.
This problem is further present when the refrigarator door is
dlmensloned rela~lve to the cablnet to carry relatively large items such
as one gallon milk containers and other large items. These larger items
may pre~ L d ~lyrl~ increase of 50% over customdIr du~s, and when
stored on the door shelves can exert a large force on the hinge side of
the cabinet. This force when excessive together with an uneven floor can
cause the hinge side of the cab;net to sag and the cabinet frame tn
deflect and form a parallelogram. In th1s situation the door would be
difficult to close and in some cases impossible.
There have been several structural arrangements to rigidify
refrlgerator cablnets. Three such arrangements are shown in U.S. Patent
Nos. 4,606,112; 4,632,470; and 4,706,363, all assigned to the same
assignee as the present lnvention. Whlle these prevlous structural
arrangements have been sat;sfactory, one of the problem~ is that there
are many components that need to be assembled together by havlng
apertures through ~he various components and then bolts or screws must
pass through the aligned apertures to secure atl of these components
together. As in any manufacturing process there is a tolerance deviatlon
bu11d-up so that the final assembled components have ~play" in them and
each cablnet can vary from the next, therefQre control of the exact
s k1ng of the width of the cabinet may not be poss1ble. Another problem
1n the prevlous structural arrangements to rigidlfy the cabinets is the
cost of the many components that were necessary to provide the rigld
structure. It ls h1ghly des1rable to elimlnate as many components as
posslble to reduce the cost nf the manufacture of the cablnet yet
mainta1n the necessary rigldlty of the cab1net. Anothar problem is how
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PATENT - Docket 9D-MA-17265 - Jenkins et al
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to assemble the refrigerator cabinet when it ls made from pre-painted
sheet metal which cannot be welded or otherwise deformed during 1ts
assembly for appearance sake.
By this invention there is proYided a method of assembling a
refrigerator cabinet wherein there is absolute control of the s king of
the width of the cabinet, thus avoidlng the tolerance build-up problem
and the method will reduce the cost of the refrigerator cabinet with the
elimination u~ ,~v~ral components heretofore thougn~ nec~ssar~ and the
method allows fcr the assembly to be made from pre-paJnted sheet met~l
components.
SUMMARY OF THE INVENTION
By the present inYention there is provided a method of
assembling a refrigerator cabinet of the type having an outer sheet metal
shall with side walls connected by a top wall forming upper front corners
lS and a front face adjacent each of said walls, an inner liner and a
partition separating freezer and fresh food compartments. The front face
is formed to include spaced front and rear panels by bending the sheet
metal at a right angle to each of the respective walls to form a first
bend and a first portion of the front panel. A second bend is made which
is a reverse bend to double the sheet metal back upon itself to form a
second portion tha~ engages the rear surface of the first portion of the
front panel to form a double layer front panel. A third bend is made at
a right angle to the double layer front panel in the area of the first
bend and a fourth bend is made at a right angle to space ~he rear panel
from the double layer front panel. A metal structure member
interconnecting the front face of each side wall is inserted into the
space between the double layer front panel and rear panel and then the
width of the outcr metal shell is si~ed to the des1red dimension. While
reta1ning the outer metal shell to the des1red dimension the d~ ole layer
PATENT - Docket 90-MA-17265 - Jenkins et al
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front panel and the metal strllctural member are pierce riveted together
adjacent each of the side walls.
BRIEF DESCR TION OF THEQ WINGS
FIG. 1 is a schematic front elevational vie~ of a refrigerator
that util k es the present invention in its assembly.
FIG. 2 is a perspectiYe view of the outer metal shell of the
household refrigerator shown in Fig. I.
FI6. 3 i~ ~ cross-sectional view taken along llnes 3-3 of Fig.
1.
FIG. 4 is a perspect~Ye view of a portion of the refrigerator
cablnet similar to that shown in Fig. 3.
~ESCRIPTION OF THE PREFERRE~ EMeODIMENT
Referring to Figs. 1 and 2 in particular, the refrigerator lO
shown is a top mount household refrigerator having a freezing compartment
12 anJ a fresh food compartment 13 separated by an insulation partition
assembly. Positioned in front of the insulation partition assembly is a
mullion bar l6, and the bottom of the refrigerator is a front rail I4.
Both the mullion bar 16 and the front ra11 l4 wh k h, as will be explained
fully here1nafter, lnsures the proper width of the cabinet between the
side walls and adds rlgidity to the cabinet to reduce deflection of
structure du~ to uneven floors or door loads of the cabinet. The
insulation partit10n assembly does not form part of the present in~ention
and accordingly will not be described in detail herein. Upon completion
of the assembly of the refrigerator and freezer compartment, the fresh
food compartments would have separate doDrs 17 and l9 respectlvely for
clos1ng the respectlve compartmenes. The refrigerator 10 has a cabinet
outer metal case or shell ]8 (F1g. 2) that has opposlte side walls 20,
22, and a top wall 23 which envelopes both the free~er and fresh food
compartments. The outer metal shell l8 has an inner liner 24 ~lg IJ
wh1ch 1s made of sheet metal or plastlc mater1al.
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PATENT - Docket 9D-MA-I7265 - Jenkins et al
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Between the innsr liner 24 and outer metal shell I8 there 1s thermal
insulation (not shown). Th;s insulation in many refrlgerators consists
of polyurethane foam which is in 1iquid form and inserted or injected
into the space between the outer metal shell I8 and the ~nner liner 24
and then cured in place. During the polyurethane foaming operation the
outer metal shell I8 may bulge or bo~ outwardly due to pressure exerted
by tha foam and thus cause some distortion of the side walls 20 and 22 of
the outer metai sne~ 8. It 1s desirable that the bowin~ or bulging of
the outer shell when it occurs be corrected and elimin'atea prior to the
final assembly of the refrigerator so that the insulation partition
assembly 15 fits correctly relatlve to the s1de walls of the liner with
no gaps between those components. Moreover, when the doors I7 and I9 of
the freezer compartment and fresh food compartment are hung it is again
important that the case width dlmensions from one side 20 to the other
side 22 be the same throughout the height of the refrigerator and that
the door openings def1ning the free~er and fresh food compartments remain
square so tha~ the doors align and seal the front openings of the
compartments I2 and I3 correctly.
Wlth particular reference to F1gs. 2-4, the components and their
arrangement involY2d ~ith the method of assembl1ng ~he refrigerator
cab1net 1n accordance with this invention will be discussed. ~hile only
one side of the refrigerator is shown in Figs. 3 and 4, it is to be
understood that the other side of the refrigerator will have the same
components and arrangement. Pr~or to the foaming operation to provide
the 1nsulation between the outer metal shell I8 and interior liner 24,
the outer metal shell is formed to provtde a front face ~6 along the side
walls 20, 22 and top wall ~3 against which the doors of the free~er and
fresh food compartments would engage and seal. The hinges 28 (Fig. I)
for the doors may be mounted on either side of the outer metal shel'. I8.
The outer shell I8 1n the present embod1ment is fabricated from
PATENT - Docket 9D-MA-17265 - Jenkins et al
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pre-painted sheet metal having a thickness generally between .014 and
.019 inches. This use of relatively thin sheet metal requires that means
be incorporated in the cabinet construction which will reduce deflection
of the cabinet. Moreover, since the metal is pre-painted it is important
that the means for rigidifying the refrigerator cabinet will not mar the
finish of the sheet metal, such as would be the case with a welding
operation. The cabinet door open1ngs defined by front face 26 may
distort out of square 1f one side sags relative to the o~ r which
results in the frame forming a parallelogram. A side may sag for example
when forces are exerted on the cabinet when it is placed on an uneven
floor or when an unexcessive weight is placed on the doors. This is
especially true in cabinets having relatively deep door shelves that are
designed to hold heavy items such as one~gallon milk containers.
As can be best seen in Fig. 3, the front face 26 is formed to
include spaced front and rear panels 30 and 32 respectively by bending
the sheet metal at a right angle designated 34 to each of the respective
side walls 20, 22 and top wall 23 to fo~m a first bend 34 and a first
portion 31 of the front panel 30. A second bend 36 ~hich is a reYerse
bend to double the sheet metal back upon ~tself to form a second portion
33 and engage the rear surface 38 of the First portion 31 of the front
panel 30 to form a double layer front panel. There is a third bend 40 at
a right angle to the double layer front panel 30 in the area of the first
bend 34 and a four~h bend ~2 at a right angle to space the rear panel 32
from the double layer front panel 30.
There is provided a metal structure member such as mullion bar
16 and front rail 14 interconnect1ng the front face of each side wall and
inserted between the double layer front panel 30 and the rear panel 32 as
shown in Fig. 2. The method of assembly will be described in connection
with securing the mullion bar 16 to the outer metal shell 18; however, it
30 1s to be :nderstood that the sallle assembly hethrd can be and ~s used 1n
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PATEN-I - Docket 9D-MA-17265 - Jenkins et a1
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the preferred embodiment for securing the front rall I4 to the bottom of
the outer metal shell I8. Therefore, the method wlll only be dsscribed
in connection with the mullion bar I6. The mullion bar 16 is formed from
pre-painted sheet me~al and has a front face 50 and an upper portion 44
reversely bent to form a bend 45 and a lower portion 46 is also reversely
bent to form a bend 48 and as can be seen in Figs. 3 and 4, the upper and
lower portion; form a double sheet metal layer throughout a major portion
of the area of tihe l~vn~ face 50. For appearance purpo;~, ~he mullion
bar 16 may have a sli~ht bend or curvature 52 as particularly shown in
Fig. 3 to accommodate the second bend 36 of the front face 26 to allow
the front panel 30 and the front face 50 of the ~ullion bar 16 to be in
the same vertical plane. It wil) be noted that the ends of the mullion
bar I6 extend a major portion of the distance between the second bend 36
and the third bend ~0 of the front face and is inserted into the space
between the front panel 30 and rear panel 32.
After the mullion bar I6 is in place, the width of the outer
metal shell is sized to the desired dimension by any suitable apparatus
and when so sized and held at the desired dimenslon the double layer
front panel 30 and the mullion bar 16 are pierce rlveted together
adjacent each of the side walls 20 and 22 of the outer metal shell I8.
Preferably, there are two pierce rivets in this area as shown in Fig. ~.
In a pierce rivet operation it is necessary that there be an anvil or
back-up tool 52 to stop movement of the pierce rivet 54 and allow the
rivet to mushroom and extend outwardly of the hole which it has just
pierced through the sheet metal. To accommodate the back-up tool 53
there is an aperture 56 in the rear panel 3Z larger than the diameter of
the back-up tool so that the tool may pass through the aperture and be in
posltion to intercept and stop further inward movement of the rivet and
allow it to mushroom as shown in Fig. 3. It will be understood also that
the plerce rlvet operation 1ncludes means for forclng the rivet through
PATENT - Docket 9D-MA-17265 - Jenkins et al
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the sheet metal wlthout the need of pre-drIl11ng or punching holes for
the r1vet to pass through. Thls ls a hammer-11ks member 58 which will
exert force on the rivet and dr1ve 1t through the double layer front
panel 30 and the double layer mullion bar 16 as shown in Fig. 3. It will
be noted that with this kind of structural arrangement and method of
securing the mull10n bar 16 to the outer metAl case I8 that there are no
apertures, cut-outs or anything else tha~ needs to be in alignment to
receive the usual threadea bolts or screws used heretofore. unce the
refrigeratDr cab1net has been correctly sized to the desirad w.dth
dimens10n and held to that dimension then the pierce riveting operation
takes place and all of the components that are riveted together will have
no ~play" in them and there will have been eliminated any tolerance
build-up that may have been the result of tolerance differences in the
various components.
As mentioned previously, the same operation can take place at
the bottom of the cab1net where the front rail l4 1s used to also
r1gidify the outer metal shell 18. The same type of metal structure
member as the mullion bar 16 may be used for the front rail I4 and again
once the cabinet 1s sized to 1ts correct w1dth dimension and held at tha~
dimension, the p1erce riveting operation takes place and rivets th& front
rail 14 to the double layer front panel 30 and the front rail 14.
Pierce rivet1ng equipment 1s available from a number of
commercial suppliers and therefore there is no need to describe the
spec1fic equipment 1n order to pract~ce th~s invention. Only ordinary
mechan1cal skill 1s needed to coordinate the sizing apparatus that may be
used with the pierce r1veting equ~pment to assure that the pierce
; riveting operat10n 1s accomplished wh11e the ~idth of the outer metal
shell 1s held to the des1red dimens10n.
It shculd be apparent to those sktlled 1n the art that the
method descr1bed here1n 1s cons1dered to be the presently preferred form
of th1s 1nvention. In accordance w1th the Patent Statutes, changes may
be made in the disclosed method w1thout actually departlng from the true
sp1rlt and scope of th1s lnYention.
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