Method of manufacturing a liner, liner, and appliance

Abstract

A method for manufacturing a liner, in particular for the cabinet of a refrigerator, allowing to leave out a deep thermoforming step. The method includes extruding a sheet, trimming the sheet, folding the sheet and joining adjacent edges of the sheet.

Claims

1. Method for manufacturing a refrigeration appliance (130), comprising: manufacturing a liner (60) for the refrigeration appliance (130) by: extruding a sheet (2), perimeter trimming said sheet (2), and folding said sheet (2) and joining adjacent edges (40, 42, 44, 46, 48, 50, 52, 54), whereby said sheet (2) is designed as a twin-wall sheet (2).

2. Method according to claim 1, wherein the method further includes a forming step of forming at least one structure into said sheet (2) before folding said sheet (2), the at least one structure comprising a protrusion, an intrusion, and/or a hole.

3. Method according to claim 2, wherein the at least one structure comprises at least one hinge (10).

4. Method according to claim 2, wherein the at least one structure comprises the protrusion or the intrusion.

5. Method according to claim 2, wherein the at least one structure comprises the hole, the hole being cut into said sheet (2).

6. Method according to claim 1, whereby said sheet (2) is made of material comprising semi-crystalline polymers.

7. Method according to claim 1, whereby said sheet (2) has a rectangular shape and perimeter trimming is performed by cutting off a substantially rectangular shape in each corner (6) of said sheet (2).

8. Method according to claim 1, whereby said cut-off rectangular shapes are identical in shape.

9. Method according to claim 1, comprising a sealing step in which edges of parts (26, 28, 30, 32) of said sheet (2) which are adjacent to each other after folding are sealed together.

10. Method according to claim 1, comprising a step of fitting the liner (60) within an outer housing (134) and attaching the liner (60) to the outer housing (134).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of some of its preferred embodiments, provided with reference to the enclosed drawings. In said drawings:

(2) FIG. 1 shows an extruded sheet;

(3) FIG. 2 shows the sheet after a method step of forming ribs;

(4) FIG. 3 shows the sheet after a method step of cutting of holes and perimeter trimming;

(5) FIG. 4 shows the sheet after a method step of forming hinges;

(6) FIG. 5 shows the sheet after a method step of folding it to obtain a box-shaped structure;

(7) FIG. 6 shows the sheet after a method step of sealing edges to obtain a liner;

(8) FIG. 7 shows a detailed view of a preferred embodiment of a hinge formed in the sheet; and

(9) FIG. 8 shows a refrigeration appliance with a liner.

DETAILED DESCRIPTION OF THE INVENTION

(10) With reference to FIG. 1, a sheet 2 is shown which has been extruded in extrusion direction 4, which is a first step or procedure of the manufacturing method according to the present invention. The extrusion process can be performed by an extruding apparatus as known from the art.

(11) The extruded sheet 2 comprises a rectangular form or shape having a side lengths which lie between 1.5-2.5 m in the present preferred embodiment. The sheet 2 is displayed in FIG. 2 after structural features such as ribs 14 and ribs 16 have been formed in a forming step. The forming step can further involve low deep drawing forming, which can be conducted by a conventional process known from the art such as vacuum forming, hot sheet forming etc. The forming step can in preferred embodiments be conducted by thermoforming or other suitable methods and is only an optional step in the described method.

(12) With reference to FIG. 3, sheet 2 is shown after it has gone through a perimeter trimming operation in which in the regions of each of its four corners 6, a substantially rectangular piece was cut off, resulting in a pre-shaped sheet 2 for the forthcoming operations. The cut-off rectangular pieces in the present embodiment are all of the same size andtaken into account mirror symmetryidentical in shape.

(13) The perimeter trimming step as described in connection with FIG. 3 has a distinct advantage over techniques known form the art: the usual step of deep thermoforming sheet 2 displayed in FIG. 1 involving high stretching of the sheet 2 to obtain the shape of the liner shown in FIG. 5 can be avoided. This way, the forming step(s) can directly follow the extrusion step, with the intermediate step of pre-shaping sheet 2.

(14) The necessity to perform large stretching operation of conventional methods limits the choice of materials for the liner: for large stretching operations, the material has to allow this procedure without getting corrupt in its consistency and constitution, which is usually only the case if an amorphous material is chosen. In the method according to the invention, since the large stretching operations are not necessary, also semi-crystalline materials such as polypropylene can be employed.

(15) In another forming step, which can also be combined with at least one of the previous forming steps, hinges 10 are formed. In FIG. 4, the sheet 2 is shown after a plurality of hinges 10 or folding lines has been formed. For this forming step, various methods known form the art can be employed. In the present embodiment, the forming station is a thermoforming station. Further referring to FIG. 3, subsequently, sheet 2 is processed to provide holes, especially for use in connection with accessories, and other structural features. As an example, an outlet for the cooling system has been formed by cutting or punching a circular hole 22 into the sheet 2. Another hole 22 with a rectangular shape has also been cut into the sheet 2 which is designed as a fixation point of a control box for the refrigerator. Hinges 10 are formed by appropriate tools, for instance heated coining heads. A preferred embodiment of the hinges will be described in connection with FIG. 7.

(16) The forming steps according to FIGS. 2, 3 and 4 can be performed in the order shown or in any other order which leads to an effective production cycle. All or a selection of these forming steps can also be performed simultaneously.

(17) Up to this stage, sheet 2 has stayed flat. The next method step involves a folding operation to obtain the liner which in the present embodiment is a cabinet liner. Sheet 2 is folded along hinges 10 in such a way that peripheral rectangular parts 26, 28, 30, 32 are folded by an angle of 90 around the respective hinges 10 which connect them to a central part 34 of sheet 2. By this folding operation, adjacent edges and folding lines of neighboring peripheral parts 26, 28, 30, 32 are moved next to each other two by two into a parallel position. This way, edges 40 and 42, edges 44 and 46, edges 48 and 50, and edges 52 and 54 are aligned next to each other. The peripheral parts 26 and 30 comprise, respectively, two flanges 36. Peripheral parts 26, 28, 30, 32 comprise border elements 56 which are folded by 90 around the respective hinges to form a frame which can serve both as a blocking element as well as a covering element when inserting the liner into the housing of a refrigerating appliance. If necessary, the edges of the sheet 2 to be joined this way can be shaped by milling to allow a seamless joining. The folding operation leads to the cabinet liner 60 displayed in FIG. 5.

(18) With respect to FIG. 6, the folding procedure results in the cabinet liner 60 with folded edges 64, 66, 68, 70 which can optionally be joined by adhesive tape and/or undergo hedge sealing. The flanges 36 have been folded by 90 and rest and/or are attached to adjacent peripheral parts 28, 30, 32, 34.

(19) After the folding step, in a foaming step the cabinet liner 60 is put into a foaming tool and foamed, after which it is ready to be deployed in a household appliance, especially a refrigeration appliance or refrigerator.

(20) An advantageous embodiment of a hinge 10 is illustrated in FIG. 7 in a side view of sheet 2. The hinge 10 comprises a first recess 80 and a second recess 84 on opposite sides of sheet 2. First recess 80 comprises a segment 88 which is basically geometrically shaped like a segment of a circle, the circle having a radius larger than a depth c of the recess 80 oriented in a direction 90 along the depth of sheet 2 and perpendicular to its surfaces. Segment 88 on both sides is connected to lines 92, 94 being parallel to direction 90, thus being perpendicular to a first and second surface of sheet 2.

(21) Second recess 84 likewise comprises a segment 106 basically being a segment of a circle which on both sides is connected to lines 110, 112 running parallel to lines 92, 94 of the first recess 80 and parallel to direction 90. The corresponding radius R of circular segment 106 is in the present embodiment 0.80 mm and smaller than the one related to segment 88, while the depth in direction 90 of the second recess 84 is approximately six times larger than the depth of the first recess. Depth c of first recess 80 is 0.15 mm as shown in the embodiment. A depth d which corresponds to the minimum distances of both recesses 80, 84, if oriented in direction 90, is between 0.2 mm and 0.4 mm. A width e of both recesses 80, 84 is 1.5 mm.

(22) Bend arrows 116, 118 indicate the folding directions of parts 120, 122 which are separated by the hinge 10 between them. After the folding operation, parts 120 and 122 will be substantially perpendicular to each other.

(23) The design of the hinges 10 is not limited to the hinge design described and can in other preferred embodiments be designed differently, as long as it allows a sufficient folding of its adjacent parts. For instance, it can be designed with triangular recesses in the sheet or any other recesses which leads a folding line and therefore to a deformable or bendable part of the sheet.

(24) With respect to FIG. 8, in a frontal perspective view, part of a refrigeration appliance 130 is shown with a cabinet liner 60, which is fit into and attached to a housing 134. In particular, the liner 60 is enclosed in an outer shell of the cabinet, and defines one or more internal compartments for food storage. Between the outer shell and the liner, an insulation layer is provided.

(25) While the present invention has been described with reference to the particular embodiments shown in the figures it should be noted that the present invention is not limited to the specific embodiments illustrated and described herein; on the contrary, further variants of the embodiments described herein are within the scope of the present invention as defined in the claims.

LIST OF REFERENCE NUMERALS

(26) 2 sheet 4 extrusion direction 6 corner 10 hinge 14 rib 16 rib 22 hole 26 peripheral part 28 peripheral part 30 peripheral part 32 peripheral part 34 central part 36 flange 40 edge 42 edge 44 edge 46 edge 48 edge 50 edge 52 edge 54 edge 56 border element 60 cabinet liner 64 folded edge 66 folded edge 68 folded edge 70 folded edge 80 first recess 84 second recess 90 direction 92 line 94 line 100 first surface 102 second surface 106 segment 110 line 112 line 116 arrow 118 arrow 120 part 122 part 130 refrigeration appliance 134 housing c depth d depth e width R radius