Refrigerator gasket assembly

A refrigerator has a cabinet with an outer case and an inner liner. The liner forms a storage compartment with an access opening. A cabinet face portion surrounds the opening and a door selectively closes the compartment. The door includes a flange which overlaps the face portion and a gasket mounted on the flange engages face portion. The gasket is an elongated body of a co-extruded material and includes a base wall of a rigid material mounted on the door frame, a contact wall spaced from the base wall for sealing engagement with the face portion and a pair of side walls connecting the base and contact walls to form a hollow interior. The contact wall includes a pair of spaced apart elongated strips of more rigid material connected by an elongated strip of less rigid material. The less rigid strip has an elongated outward projecting bow shape. The side walls are indented in a "V" shape and the apex of the V has a reduced thickness. A strip of fiber glass, with a net like backing on one side, is in the interior of the gasket.

BACKGROUND OF THE INVENTION 
For a number of years the doors of refrigerators have been held closed by 
cooperating strips of magnetic material. This required that the face 
portion of the cabinet surrounding each of the storage compartments 
include a substantial strip of magnetic material, normally a portion of 
the steel outer case. Also the gaskets normally included extensive strips 
of magnet material which were attracted to the steel outer case face 
portion to hold the door closed and pull the gasket to the steel outer 
case to form a good seal. Such constructions do not provide optimum heat 
sealing of the compartment, even though they employ relatively high 
sealing pressures. For example, the metal in the cabinet face portion and 
door flange, as well as the magnet, increase the heat conduction. 
With the increased need to reduce the energy consumption of refrigerators, 
it is desirable to reduce the heat transfer through the door seal area. 
One approach has been to modify the cabinet and door construction so that 
there is less metal in the cabinet face portion. This leads to the need to 
substantially reduce or eliminate the magnets as the means of holding the 
door closed; which results in a much lower force being available to urge 
the door to its closed position. 
With such low force constructions there is a need for the gasket to be soft 
and easily compressible to assure a good seal. At the same time the gasket 
must return to substantially its original shape despite many door opening 
and closing operations and despite the fact that during the life of the 
refrigerator the door will be closed, with the gasket compressed, most of 
the time. 
At least most plastic materials from which it is reasonable to extrude 
flexible gaskets have fairly high coefficients of friction with the 
cabinet face portion. As a refrigerator door opens and closes, the contact 
wall of the gasket slides across the cabinet face portion. When the gasket 
contact wall/cabinet face portion have a fairly high coefficient of 
friction, the gasket contact wall will adhere to or "scrub" against the 
cabinet, resulting in poor seals and shortened gasket life. 
It is therefore an object of this invention to provide an improved 
refrigerator gasket assembly. 
It is another object of this invention to provide such an improved gasket 
assembly which requires only a small force to compress the gasket for a 
good seal. 
It is yet another object of this invention to provide such an improved 
gasket assembly which has long life. 
SUMMARY OF THE INVENTION 
In accordance with one form of the invention a refrigerator comprises a 
cabinet with an outer case and an inner liner. A storage compartment 
formed by the liner has an access opening surrounded by a cabinet face 
portion. A door is hinged to the case along one edge for selective closing 
of the access opening. The door has a flange which overlies the cabinet 
face portion when the door is in its closed position. An elongated gasket 
is mounted to the door flange to seal against the cabinet face portion 
when the door is closed. The gasket comprises an elongated body of 
co-extruded plastic material including an elongated base wall of 
relatively rigid material mounted on the door flange, a contact wall 
overlying and spaced from the base wall for sealing engagement with the 
face portion and a pair of spaced apart, flexible side walls joining the 
base and contact walls and forming therewith a hollow gasket interior 
containing a compressible material. The contact wall comprises alternate 
longitudinally extending strips of more rigid and less rigid material.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
In FIG. 1 there is illustrated a household refrigerator 10 of the 
side-by-side type; that is a freezer storage compartment 11 and a fresh 
food storage compartment 12 are arranged side-by-side within the 
refrigerator. The refrigerator 10 has a cabinet including an outer case 14 
and an inner liner 16, with the space between them filled with 
foamed-in-place insulation 18 (See FIG.'S 5 and 7). The outer case 
normally is formed by folding a sheet of a suitable material such as 
painted steel and the inner liner 16 is molded of a suitable plastic 
material or is formed from a sheet of metal to define the freezer 
compartment 11 and the fresh food compartment 12. The liner may be formed 
as a single shell defining both compartments or as two separate shells, in 
which case a mullion will be placed between them. In either event the 
liner can be considered as a single element. The front of the cabinet 
includes a face portion 20 which surrounds the front access openings of 
the freezer and fresh food compartments. Conveniently, the outer case has 
an inward projecting front peripheral flange and a breaker strip bridges 
the gap between the flange and the front edge of the liner. The breaker 
strip normally is molded of a suitable plastic material such as, for 
example, an acrylo-butadiene-styrene (commonly referred to as ABS) 
material, a styrenic material or an olefin material. The face portion 
normally is formed by the parts of the outer case flange and the breaker 
strip which face the front of the refrigerator. In the low force 
constructions referred to above the door mounted gasket normally engages 
the part of the face portion formed by the plastic breaker strip. 
A freezer door 22 and a fresh food door 24 close the access openings to the 
freezer and the fresh food compartments respectively. Each is mounted by 
top hinges 26 and bottom hinges, not shown, to rotate about its outer edge 
between an open position, shown in FIG. 1, and a closed position closing 
the associated storage compartment. Conveniently both doors are made with 
the same basic construction, and it will be understood that the following 
description of freezer door 22 also applies to fresh food door 24. 
Viewing FIG.'S 1 and 3, door 22 includes an outer door panel 27, normally 
formed by a folded sheet of painted steel, which has a front, not shown, 
and a generally perpendicular lateral wall 28 forming top. bottom and 
sides of the door. The lateral wall ends in an inwardly projecting 
peripheral flange 30, lying in a plane parallel to and spaced from the 
door front. An inner door panel 32, normally molded from a suitable 
plastic material, includes a peripheral flange 34 which overlies the outer 
door panel flange 30. The inner panel 32 is mounted on and supported by 
the outer panel 27 by means of a connection strip 36 which overlies the 
outer edge of the inner panel flange 34 and is secured to the outer panel 
flange 30 by screws 38. Within the flange 34 the inner panel is formed 
with a wall 40 projecting away from the outer panel to be received in the 
storage compartment when the door is closed. The wall 40 supports 
removable shelves 42 for items to be stored. In addition, the inner panel 
can be formed with integral features such as an ice dispenser 44 (door 22) 
or a butter and cheese keeper 46 (door 24). Conveniently the space between 
the inner and outer door panels also is filled with insulation. 
A gasket 48 extends around the periphery of the freezer door 22 and engages 
the cabinet face portion 20 surrounding the freezer 11 when door 22 is 
closed. More specifically, gasket 48 overlies the portion of door 22 
comprised of outer door panel flange 30, inner door panel flange 34 and 
connection strip 36. Gasket 48 is mounted to the door by an adhesive 50 
which connects it to the strip 36 (see FIG. 3). 
A gasket 52 extends around the periphery of the fresh food door 24 and 
engages the cabinet face portion surrounding the fresh food storage 
compartment 12 when door 24 is closed. The gasket 52 is wider than the 
gasket 48. Otherwise the construction is the same. Therefore, it will be 
understood that the following description of casket 48 also applies to 
gasket 52. Gasket 48 is made from a length of extruded plastic material 
having the desired cross section shape. Desired lengths are cut with 
mitered corners and are joined, as by welding or gluing for example, to 
form an open rectangle or picture frame configuration. As will be 
explained in more detail hereafter, the gasket is co-extruded of two or 
more different plastic materials and/or a material having two or more 
thicknesses to provide different portions of the gasket with different 
desired characteristics. 
It will be understood that, for the purposes of this invention, a "rigid" 
plastic material has a Shore D Durometer hardness between about 60 and 
about 95, and preferably between about 80 and about 90; a "semi-rigid" 
plastic material has a Shore D Durometer hardness between about 45 and 
about 70, and preferably between about 50 and about 60; and a "flexible" 
plastic material has a Shore A Durometer hardness between about 50 and 
about 90, and preferably between about 70 and about 85. 
It is contemplated that the gasket can be co-extruded with a plurality of 
entirely different compatible plastic materials. However, the 
exemplification embodiment was co-extruded with a number of somewhat 
different formulations of polyvinyl chloride (commonly referred to as 
PVC). Rigid PVC materials have essentially no plasticizer; semi-rigid PVC 
materials have up to about 10% plasticizer; and flexible PVC materials 
have between about 10% and about 40% plasticizer. In formulating the 
materials for the exemplification embodiment, the per cent of plasticizer 
in the material for each part of the gasket was empirically determined to 
provide a material hardness the preferred range. 
Referring now more particularly to FIG.'S 3 and 4, gasket 48 includes an 
elongated base wall 54 which is seated against the flange area of the 
freezer door 22; an elongated contact wall 56 which overlies and is spaced 
from the base wall 54 to engage the cabinet face portion 20 when the door 
is closed; and a pair of opposed. spaced apart elongated side walls 58, 60 
which connect the base and contact walls 54, 56, to form therewith a 
hollow gasket interior 57. 
Base wall 54 is formed from a suitable relatively rigid plastic material 
such as semi-rigid or rigid PVC with a Shore D Durometer hardness between 
about 45 and about 95, and preferably between about 50 and about 90. 
Typically a semi-rigid/rigid PVC base wall with a thickness between about 
0.018 inch and about 0.027 inch will provide the gasket with excellent 
dimensional stability. That is, the gasket extrusion will be straight, 
even though the other walls are not as rigid as base wall 54. Also the 
extrusion can be cut to length with precision to form the top, bottom and 
side portions of the gasket. In this regard, a length tolerance of plus or 
minus about 0.075 inch is desirable. Once the gasket is assembled to a 
door, the base wall substantially prevents the various portions of the 
gasket from sagging under the influence of gravity. From a structural 
characteristics standpoint it is preferable to extrude the base wall 54 of 
a rigid material; however, for ease of manufacture, it may be preferable 
to extrude base wall 54 of a semi-rigid material to coincide with the 
material of some other portions of the gasket. 
The contact wall 56 has a three section construction with elongated side 
portions or strips 62, 63 joined by an elongated central portion or strip 
64. The central strip 64 has a longitudinally extending outward bow 
configuration. Preferably the side strips 62, 63 are extruded from 
semi-rigid or rigid plastic material, such as PVC with a Shore D Durometer 
hardness between about 45 and about 95 and preferably between about 50 and 
about 90. The central strip is extruded from a flexible material, such as 
flexible PVC with a Shore A Durometer hardness between about 50 and about 
90 and preferably between about 70 and about 85. As the door closes the 
contact wall initially slides across the cabinet face portion 20, 
particularly along the side of the gasket nearest the axis of rotation of 
the door. If the coefficient of friction between the gasket and the face 
portion is greater than about 0.3, the gasket will tend bind or scrub on 
the face portion and a good seal will not be obtained. In fact, the 
scrubbing action can be so extreme as to prevent the door from fully 
closing. With the construction of the contact wall 56, the side portion or 
strip 63 first contacts the face portion 20 and coefficient of between the 
rigid/semi-rigid PVC and the face portion 20 is less than 0.3. Thus the 
gasket does not tend to bind or scrub. 
The elongated outwardly bowed or bubble shaped central strip serves several 
purposes. First, it imparts a desired greater degree of flexibility to the 
contact wall. Second, in the event the gasket is not extruded in a 
perfectly straight configuration or one or more of the corners is not 
perfectly square, a twisting stress is imparted to the contact face and 
the flexible bubble strip 64 relieves the twisting stress and improves the 
planarity of the side portions 62, 63. Third, when the door is fully 
closed, as shown in FIG. 5 for example, the contact between the contact 
wall 56 and the face portion is essentially along three parallel lines. 
That is only the outer edge portion of each side strip 62, 63 and the 
center of bubble strip 64 are in engagement with the face portion 20 
(generally as seen in FIG. 5). This distinct line contact provides a surer 
seal than is obtained by using the entire surface of contact wall 56. 
A gasket which feels soft to the touch impresses many users as having poor 
sealing characteristics, even though it may seal very well. The contact 
wall 56, with its stiffer side strips 62, 63 and its more flexible center 
strip 64, presents a fairly stiff feel to the touch, which imparts a sense 
of "quality" to the user of the refrigerator. 
The side wall 58 is in the form of an elongated, horizontally oriented "V" 
with its apex 66 inward of the lateral edges of the base and contact 
walls. The side wall 58 preferably is extruded of a flexible material such 
as PVC with predetermined thicknesses. The thickness of the side wall 58 
is reduced along the apex 66 and along each of its distal edges 68, 69, 
where the wall 58 joins base wall 54 and contact wall 56, respectively. 
Thicker sections 70, 71 extend between the reduced thickness sections. The 
end wall 60 is a mirror image of end wall 58, in the form of a "V" with 
its apex inward of the adjacent lateral edges of base wall 54 and contact 
wall 56. The apex 74 and distal edges 76, 77 of wall 60 have a reduced 
thickness while the intermediate sections 78, 79 are thicker. 
The reduced thickness sections 66, 68, 69 and 74, 76, 77 act as hinges so 
that, when the gasket is compressed, the thicker sections 70.71 and 78, 79 
move toward each other and then separate when the compression force is 
removed. The thicker sections 70, 71 and 78,79 provide structural strength 
to the side wall and act as a source of platicizer which slowly migrates 
to the adjacent hinge sections and helps them maintain their flexibility 
over time. In the exemplification embodiment the side walls are extruded 
of a flexible plastic such as PVC with the thicker sections 70, 71 and 78, 
79 having a thickness of between about 0.020 inch and about 0.025 inch and 
with the hinge sections 66, 68, 69 and 74, 76, 77 having a thickness of 
between about 0.008 inch and about 0.014 inch. 
An elongated lip 80 projects outward of the junction between contact wall 
56 and end wall 60. When the gasket is mounted on the door, the lip 80 
engages the door inner panel wall 40 and provides a smooth seal between 
the inner panel 32 and the gasket 48. In addition, it provides additional 
support which helps prevent sideways distortion of the side of the gasket 
closest to the axis of rotation of the door as the door closes. An 
elongated flap 82 projects outward from the junction of the base wall 54 
and the end wall 58. When the gasket 48 is mounted on the outer door 22, 
the flap 82 engages the door outer panel at the junction between the 
lateral wall 28 and the peripheral flange 30 and provides a good seal 
between the gasket and the outer door panel, preventing exterior moisture 
migration. 
In order to form an open rectangle or picture frame gasket, such as 48 or 
50, the extruded length of gasket material is cut into individual pieces 
with lengths corresponding to the top, bottom and sides of the gasket. 
Referring now to FIG. 2, there is shown the top left corner (as viewed in 
FIG. 1) of the gasket 48. The mating corners of the top gasket piece 83 
and side gasket piece 84 are formed with appropriate miters 86, 88 and the 
pieces are joined by welding or other suitable means to form a right angle 
corner. All four corners are similarly formed to provide the picture frame 
gasket. Adjacent each corner of the gasket, the inner side wall of each 
gasket piece is formed with a cutout, as shown at 90. 
Strips of insulation material are cut to coincide in length and shape to 
each gasket piece. Once the gasket has been welded into its picture frame 
shape, a strip of insulation material of the proper length and mitered 
corners is inserted into each gasket piece through the cutouts 90. While a 
separate strip of insulation is inserted into each gasket piece, the 
insulation strips meet at the gasket corners and can be considered as one 
strip. Of course, if desired, a suitable strip of insulation material can 
be inserted into the extended length of gasket material before it is cut 
into individual pieces. 
The insulation material has low heat conductivity to enhance the insulating 
capacity of the gasket. In addition, it acts as a spring. That is, when 
the door is closed, the insulation material is compressed and then, when 
the door is subsequently opened, the insulation springs back and aids in 
returning the gasket to its original configuration. With a low closing 
force system it is desirable that only a very low compression force be 
needed to compress the insulation; such as, for example, between about 
0.015 pound per square inch and about 0.025 pound per square inch will 
compress the insulation about 30%. It also is desirable that the gasket, 
including the insulation material, have a low spring rate such that, for 
example, a compression force between about 0.06 and about 0.90 pounds per 
square inch will compress the gasket about 30%. 
In the exemplification embodiment the insulation is formed of a strip 94 of 
fiber glass having a low density on the order of 0.5 pounds per cubic 
foot. A net like open mesh backing or cover 96 of suitable material, such 
as a synthetic fiber like polyester, is adhered to at least one side of 
the fiber glass strip, preferably adjacent either the gasket base wall or 
contact wall. The backing provides axial strength to the insulation strip 
92 so that it can be pulled through the gasket. If it is desired to 
provide greater stability and strength to the insulation strip 94, backing 
can be adhered to two opposite sides of the strip, preferably adjacent 
both the base and contact walls of the gasket. In the exemplification 
embodiment the strip 92 of insulation material is generally rectangular in 
cross section, with a thickness sufficient to extend substantially 
completely between base wall 54 and contact wall 56 and with a width 
sufficient to extend substantially completely between apex 66 of side wall 
58 and apex 74 of side wall 60. 
Under some extreme conditions, such as when the ambient temperature is 
above about 90 degrees F., the outer edges of the gasket contact wall 56 
may need to be even stiffer. Referring now to FIG. 4, a small elongated 
rib 98 extends perpendicularly to each of the contact wall side portions 
62, 63 into the interior of the gasket. These ribs provide the additional 
desired stiffness. Under some extreme conditions, such as when the ambient 
temperature is above about 90 degrees F., the side wall 58 may tend to 
fold outward when the gasket is compressed. An elongated gusset 100 
connected between thicker side wall section 70 and base wall 54 will 
assure that the side wall folds inward, even under extreme conditions. 
Referring now to FIG. 6, there is illustrated a gasket incorporating 
another embodiment of the present invention. Except for the contact wall, 
the gasket of FIG. 6 is the same as that shown in FIG.'S 1-5 and like 
numerals have been used for like parts. The contact wall 102 is extruded 
from a continuous width of a thick, flexible material, such as flexible 
PVC. Such material has a high coefficient of friction with the cabinet 
face portion 20 and would "scrub" on the face portion. To prevent such 
scrubbing, a series of elongated, laterally spaced apart strips 104 of a 
more rigid material are extruded along the outside surface of the wall 
102. The strips 104 engage the cabinet face portion and do not scrub. The 
contact wall 102 does not tend to twist if welded slightly off square or 
not extruded perfectly straight. In addition, the corner welds are very 
strong and have a better appearance than the gasket of FIG.'S 1-5. In the 
exemplification embodiment the wall 102 is an extrusion of flexible PVC 
about 0.06 inch thick with a Shore A Durometer hardness of about 70; and 
the strips 104 are extruded of rigid/semi-rigid PVC about 0.01 inch thick, 
with a coefficient of friction with the cabinet face portion between about 
0.1 and about 0.3 and with a Shore D Durometer hardness of about 70. 
Many of the features and advantages of the present invention can be 
incorporated into gaskets utilizing long magnet members to obtain high 
door closing forces. FIG. 7 illustrates such a construction in which the 
gasket is basically the same as previously described, except for the 
contact wall and the magnet material, and like numbers have been used to 
identify like parts. The contact wall 106 includes a right hand strip (as 
seen in FIG. 7) which is a relatively thick extrusion of semi-rigid or 
rigid PVC and a left hand strip 110 which is relatively thin extrusion of 
flexible PVC. The left hand portion of wall 106 also includes a backing 
sheet 112 which, together with strip 110 and a part of side wall 58, forms 
an elongated pocket 114. Magnetic material, such as a flexible strip 
magnet 116, is positioned within the pocket 114. A strip 118 of magnetic 
material, such as steel of a strip magnet, extends along the inside of the 
cabinet face portion 20 in alignment with the strip magnet 116. The strips 
116, 118 attract each other and provide the desired closing force. The 
embodiment of FIG. 7 assumes that face portion 20 is formed by a 
non-ferrous breaker strip. If the face portion is formed at least in part 
by the ferrous outer case, then the magnetic strip 118 can be omitted as 
the strip magnet 116 will be attracted to the magnetic outer case. 
While specific embodiments of the invention have been illustrated and 
described herein, it is realized that modifications and changes will occur 
to those skilled in the art to which the invention pertains. It is 
therefore to be understood that the appended claims are intended to cover 
all such modifications and changes as fall within the true spirit and 
scope of the invention.