BACKGROUND OF THE INVENTION

[0001] Various types of insulated refrigerator cabinet structures have been developed. A known type of refrigerator cabinet includes a metal wrapper and a polymer liner. Polyurethane foam is injected between the wrapper and the liner to provide insulation and support the wrapper and liner. Various types of vacuum insulated refrigerator cabinet structures have also been developed. However, known refrigerator cabinets may suffer from various drawbacks.

SUMMARY OF THE INVENTION

[0002] One aspect of the present invention is a method of making a vacuum insulated refrigerator cabinet structure. The method includes thermoforming a first polymer sheet to form a wrapper having a base wall and four sidewalls, wherein each sidewall includes inner and outer sides. The four sidewalls extend transversely from the base wall to form four elongated inside corners and a main opening. The method also includes thermoforming a second polymer sheet to form a liner having a base wall and four sidewalls, wherein each sidewall includes inner and outer sides. The sidewalls extend transversely from the base wall. Each sidewall of the liner includes a free edge opposite the base wall forming a main opening. The method further includes adhesively securing an elongated corner stiffener to each elongated inside corner of the wrapper. Each elongated corner stiffener includes an opening. A resilient ring is secured to the liner adjacent to the free edges of the sidewalls. The resilient ring includes four corners, and each corner includes a pin projecting from the corner. The method further includes positioning the liner inside the wrapper to form a cavity between the wrapper and the liner. The pins of the resilient ring are received in the openings of the elongated corner stiffeners. The resilient ring extends between the inner sides of the wrapper sidewalls and the outer sidewalls of the liner to seal the cavity. The resilient ring is adhesively sealed to the wrapper and to the liner. Porous material is disposed in the cavity between the wrapper and the liner. A vacuum is formed in the cavity, and the cavity is sealed to maintain the vacuum. [0003] These and other features, advantages, and objects of the present device will be further understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] In the drawings:

[0005] FIG. 1 is an isometric view of a refrigerator;

[0006] FIG. 2 is an exploded isometric view of a liner and wrapper assembly of the

refrigerator of FIG. 1;

[0007] FIG. 3 is a cross-sectional view of a portion of the wrapper assembly of FIG. 2;

[0008] FIG. 4 is a cross-sectional view of a portion of the wrapper assembly of FIG. 2;

[0009] FIG. 5 is an isometric view of a liner and resilient ring during assembly;

[0010] FIG. 6 is an isometric view of a liner and resilient ring during assembly; and

[0011] FIG. 7 is a cross-sectional view of a portion of the liner, wrapper, and resilient ring in an assembled condition.

DETAILED DESCRIPTION OF EMBODIMENTS

[0012] For purposes of description herein the terms "upper," "lower," "right," "left,"

"rear," "front," "vertical," "horizontal," and derivatives thereof shall relate to the device as oriented in FIG. 1. However, it is to be understood that the device may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0013] With reference to FIG. 1, a refrigerator 1 includes a cabinet 2 and doors 4 and 6 that are movably mounted to the ca binet 2 for rotation about a vertical axis in a manner that is generally known in the a rt. Refrigerator 1 may include a refrigeration system 8 of a known type including a compressor, condenser, expansion valve, evaporator, tubing, and/or other related components (not shown). [0014] Refrigerator 1 includes a vacuum insulated cabinet structure 10 that includes a wrapper assembly 12 and a liner assembly 14 (see also FIG. 2). An outer covering 16 may optionally be positioned over the cabinet structure 10 to provide the desired exterior appearance. The outer covering 16 may comprise sheet metal or other suitable material.

[0015] With reference to FIG. 2, wrapper assembly 12 includes a polymer wrapper member 18 that is thermoformed from a sheet of polymer material utilizing known thermoforming processes. The polymer wrapper member 18 includes a generally rectangular base wall 20 and four sidewalls 22A-22D that extend transversely from the base wall 20 to form corners 36. Base wall 20 includes an inner surface 17, and an outer surface 19 (FIG. 4). Sidewalls 22A-22D include inner surfaces 21A-21D, respectively, and outer surfaces 23A-23D, respectively. The base wall 20 has a generally planar central portion 24, and may optionally include one or more reinforcing features such as transverse portions 26 and raised portions 28 and 29 (see also FIG. 4) that extend around a perimeter 32 of base wall 20 to provide stiffening and/or to provide location features for an optional base stiffener member 34. As discussed in more detail below, the optional base stiffener member 34 is ring-shaped, and may be adhesively secured to corner 36 which is formed at the junction of base wall 20 and sidewalls 22A and 22D.

[0016] The wrapper member 18 may be thermoformed from suitable polymer materials such as ABS, HIPS, PVC, etc., utilizing known methods. Corners 38A-38D formed at the intersection of the sidewalls 22A-22D may have a relatively large radius. For example, the corners 38A-38D may have a radius of about 1.0 inch to about 6.0 inches or more. The enlarged radii at corners 38A-38D facilitates thermoforming of wrapper member 18, and eliminates a sharp outer corner that may be subject to damage. However, it will be understood that the corners 38A-38D may alternatively comprise sharp corners having a radius of 0.0 inches to 1.0 inch. During assembly, after thermoforming of the wrapper member 18, elongated corner stiffeners 40A-40D are adhesively secured to corners 38A- 38D, respectively. Elongated corner stiffeners 40A-40D include openings 42A-42D, respectively that face towards peripheral edges 44A-44D of sidewalls 22A-22D, respectively, of wrapper member 18. The outer ends 46A-46D of elongated corner stiffeners 40A-40D, respectively, are spaced inwa rdly from peripheral edges 44A-44D by a distance "X." As discussed in more detail below, this provides clearance for assembly with liner assembly 14. [0017] With reference to FIG. 3, the corner stiffeners 40A-40D include a n elongated cylindrical cavity 48 that forms open ends 42A-42D. A cylindrical sidewall 50 includes a cylindrical outer surface portion 52, such that the sidewall 50 has a generally uniform thickness except in a region 54 adjacent corners 38A-38D. The elongated corner stiffeners 40A-40D also include flaps or wings 56A and 56B that extend outwardly from sidewall 50 along the sidewalls 22A-22D of wrapper member 18. Adhesive 58 is disposed between the corner stiffeners 40A-40D and wrapper member 18 to adhesively secure the corner stiffeners 40A-40D to the wra pper member 18. Adhesive 58 may comprise 3M™ DP125 epoxy adhesive, Henkel Loctite ^® E90-FL 1 epoxy adhesive, or other suitable known adhesive. The elongated corner stiffeners 40A-40D may be made from a polymer material such as ABS, HIPS, PVC, etc., or other suitable material. Although the corner stiffeners 40 preferably comprise a polymer material, corner stiffeners 40 may comprise extruded aluminum or the like.

[0018] With further reference to FIG. 4, an optional base stiffener member 34 may be adhesively secured to inside 60 of corner 36 of wrapper 18. If a base stiffener member 34 is to be installed, the base stiffener member 34 is preferably installed prior to installation of the corner stiffeners 40A-40D. Adhesive 62 may be utilized to secure the base stiffener member 34. Adhesive 62 may be identical to adhesive 58, or other suitable adhesive. The base stiffener member 34 may comprise a polymer material such as ABS, HIPS, PVC, etc., or other suitable polymer or metal material. The base stiffener member 34 is preferably a one piece ring-shaped member. However, base stiffener member 32 may also comprise a multi-piece member.

[0019] With further reference to FIGS. 5 and 6, liner assembly 14 includes a liner member

15 and a resilient ring 64 that is installed to liner member 15 by sliding resilient ring 64 onto liner member 15 in the direction of the arrow "A" (FIG. 5). As discussed in more detail below, resilient ring 64 includes pins 86A-86D that are received in openings 42A-

42D, respectively, of corner stiffeners 40A-40D, respectively, when liner assembly 14 is assembled with wrapper assembly 12. Liner member 15 is thermoformed from a sheet of polymer material utilizing known processes. Liner member 15 includes a base wall 66 and sidewalls 68A-68D that extend transversely from base wall 66 (see also FIG. 2).

Sidewalls 68A-68D include inner surfaces 70A-70D, respectively, and outer surfaces 72A-

72D, respectively. Sidewalls 68A-68D include edges 80A-80D that extend around opening 68D form corners 82A-82B, and the intersection of sidewalls 68A-68D with base wall 66 forms corners 84A-84D, respectively. The corners 82A-82D and 84A-84D may have relatively large radii such that a generally uniform gap is formed between the corners of liner member 15 and wrapper member 18.

[0020] With further reference to FIG. 7 peripheral edge 80 of liner member 15 includes a first transverse portion 94 that extends outwardly, and a second portion 96 that includes a curved end portion or lip 98 that forms a concave groove 100 that faces away from opening 78. Resilient ring 64 is generally S-shaped in cross section, and forms a first channel 102 that faces inwardly, and a second channel 104 that faces outwardly. Resilient ring 64 is preferably made of a flexible polymeric or elastomeric material. A flap or edge 106 of resilient ring 64 includes an outer surface 108 that seals against inner surfaces 21A-21D of wrapper member 18. The outer dimension defined by outer surface of flap 106 is preferably somewhat greater than the dimension across opening 25 of wrapper member 18 such that the resilient ring 64 forms an interference fit when assembled as shown in FIG. 7.

[0021] As discussed above, resilient ring 64 is initially installed on liner member 15 by sliding resilient ring 64 onto liner member 15 as shown in FIGS. 5 and 6. As the resilient ring 64 is moved to the fully installed position shown in FIGS. 6 and 7, a curved portion 110 of resilient ring 64 forming channel 102 contacts concave surface 100 of curved end portion 98 of edge 80 of liner member 15. Adhesive such as 3M™ DP125 or Loctite ^® E90- FL or other suitable adhesive is utilized to adhesively secure resilient ring 64 to liner member 15.

[0022] Prior to positioning liner assembly 14 in wrapper assembly 12, adhesive 90 may be positioned in first channel 102 to ensure that seam 112 is sealed at the line of contact between liner member 15 and resilient ring 64. Adhesive 92 may also be positioned in elongated cavities 48A-48D of corner stiffeners 40A-40D, respectively, adjacent the openings 42A-42D.

[0023] After the corner stiffeners 40 are adhesively secured to wrapper member 18 to form wrapper assembly 12, and after resilient ring 64 is adhesively secured to liner member 15 to form liner assembly 14, the liner assembly 14 is then positioned inside of wrapper assembly 12. As the liner assembly 14 is positioned in wrapper assembly 12, the pins 86A-86D are received in openings 42A-42D, and the pins 86A-86D become embedded in the adhesive 92. Pins 86A-86D may have a tapered end portion 114 to facilitate insertion of pins 86A-86D into openings 42A-42D during assembly. As shown in FIG. 7, pins 86A-86D may have an outer diameter Dl that is significantly smaller than an inner diameter D2 of cylindrica l cavities 48A-48D. The large clearance facilitates assembly while maintaining a required degree of alignment between the components. After the liner assembly 14 is inserted into wrapper assembly 12, adhesive 88 may be deposited into second channel 104 to ensure that the seams 116 and 118 formed between resilient ring 64 and wrapper member 18 and liner member 15, respectively, are sealed. Adhesive 88 may fill channel 104 and also fill region 102 between curved end portion 98 of liner member 15 and wrapper member 18. Adhesives 88, 90, and 92 may be identical to adhesive 58, or other suitable adhesive. Alternatively, other suitable adhesive may be utilized. After the liner assembly 14 is installed in wrapper assembly 12, a trim member 122 may be adhesively secured to liner member 15 and/or wrapper member 18 to close off channel 104 and to provide a smooth exterior appearance. Also, a sheet metal outer skin may be positioned over the wrapper assembly 12 to provide a finished outer surface that includes sharp outer corners 11A-11D (FIG. 1).

After the adhesive 88, 90, and 92 cures, the cabinet structure 10 forms a rigid structure defining a cavity 124 between the wrapper assembly 12 a nd liner assembly 14. Sidewalls 22A-22D and base wall 20 of wrapper 12 may be spaced apart from sidewalls 68A-68D and base wall 66, respectively, of liner 14 such that cavity 124 extends around substantially the entire cabinet structure 10. The cavity 124 may be filled with porous filler material 126. The porous filler material 126 may comprise silica powder that is introduced through one or more openings 128 in liner member 15 and/or wrapper member 18. The cabinet structure 10 may then be subject to a vacuum to thereby evacuate cavity 124, and one or more caps 130 or other suitable devices may be utilized to close and seal openings 128 to ensure that cavity 124 maintains a vacuum. The vacuum may be formed by positioning the cabinet structure 10 in a vacuum chamber (not shown) prior to installing caps 130 over openings 128. The caps 130 may then be installed to seal openings 128 while the cabinet structure 10 is in the vacuum chamber, and the cabinet structure 10 is then be removed from the vacuum chamber. [0025] Liner member 15 and/or wrapper member 18 may be thermoformed from a thermoplastic polymer sheet including outer layers that comprise a suitable thermoplastic polymer material such as High Impact Polystyrene (HI PS) or Acrylonitrile, Butadiene and Styrene (ABS). The sheet may include a barrier layer that comprises a thermoplastic polymer material that is impervious to one or more gasses such as nitrogen, oxygen, water vapor, carbon dioxide, etc. such that the liner member 15 and wrapper member 18 provide a barrier to permit forming a vacuum in cavity 124. The barrier layer preferably comprises a material that blocks both oxygen and water vapor simultaneously. Examples of such material include Polyvinylidene Chloride (PVdC), nylon, or liquid crystal polymer.

[0026] Alternatively, the inner and/or outer surfaces of liner member 15 and/or wrapper member 18 may be coated after thermoforming utilizing plasma polymerization or Physical Vapor Deposition (PVD) processes. The coatings applied by these processes block oxygen, nitrogen, water vapor, and other gasses. The coating may comprise an organic or inorganic material such as silicon oxide that is deposited utilizing a plasma polymerization process. The coating may comprise a metallic layer such as aluminum, stainless steel, chrome, or other suitable metal that is applied utilizing a Plasma Vapor Deposition (PVD) process. The coating provides a barrier that blocks gasses to maintain the vacuum formed in cavity 124. An additional outer layer (not shown) in the form of a polymer protective cap may optionally be applied over the barrier coating. Resilient ring 64 may also include a barrier layer and/or a barrier coating.

[0027] Referring again to FIG. 1, the liner member 15 and wrapper member 18 may optiona lly include a stepped lower rear portion 132 that includes an upright wall portion 134 and a horizontal wall portion 136. The stepped portion 132 provides a space 138 that is outside of the cavity 140 of cabinet structure 10 to permit mounting of refrigerator system components 8.

[0028] It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present device, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.