Description REFRIGERATOR DOOR CONSTRUCTION
[001] The present invention refers to a new method for producing a door for a refrigerating apparatus, in particular a household refrigerators.
[002] Refrigerators, freezers and similar apparatuses are typically provided with insulated doors. These doors are usually constructed of an outer panel and an inner liner with a foam insulation between them. Different types of materials are used for the door panels, so as different methods are used to assemble them. The most typical construction involves a metal fabricated exterior door shell that is formed with a rear flanges on the back side to support and possibly attach a thermoformed plastic interior panel. The typical insulation material is a polyurethane foam which is introduced into the door by means of three basic approaches: laminated in the exterior shell up to the rear flanges, injected into a small opening of a preassembled door, or poured into one half of the door assembly and foamed in place when the outer door half is clamped down before the foam begins to expand and cure. Examples of refrigeration door construction are disclosed in US 5,520,453, US 5,588,731, and US 5,909,937.
[003] A main problem in the construction of refrigeration doors is the sealing of the space between the external shell and the inner liner which is to be filled up by the insulation material. Normally, metal or plastic rims engine the edges of the panels, both at top and at bottom thereof, respectively. Said rims are suitably shaped, e.g. C-shaped, to cover and enclose the panel edges, as they are applied to the panels from outside of the same. This solution involves some drawbacks. Rrstly, rims should be firmly attached to the panels to avoid a possible detachment under the foaming pressure which is produced during the filling up of the insulation material. Moreover, the free ends of the rims project from the surface of the door panels, so causing problems to the users for the cleaning of the refrigerators.
[004] Another problem may arise when non-coated metal panels are used for the construction of the refrigerating door. Indeed, protruding ribs on surfaces to be painted create an additional problem both for the technical production and from the aesthetic point of view of the finished apparatus.
[005] Therefore, it is an object of the present invention to provide a new refrigerator or freezer door construction which comprises an outer panel and an inner liner so as a top rim and a bottom rim, said components being assembled in an innovative way to close the internal space of the door wherein a foam insulation must be produced.
[006] Another object of the present invention is to provide a new refrigerator or freezer door having an external surface fully smooth in order to improve the door finishing both from the technical and aesthetic point of view. Yet another object of the present invention is to provide a new refrigerator or freezer door which facilitates cleaning operation and makes it more safe too.
[007] The features of the invention are pointed out in the appended claims. Features and advantages of the invention will be better understood by the following description with reference to the accompanying figures. 1 should also be understood that the particular embodiment hereinafter disclosed is exemplary only and not to be regarded as a limitation of the present invention.
[008] Figure la represents a partial sectional view, on enlarged scale, of a refrigerator door according to the prior art;
[009] Figure lb represents, similarly to Figure la, a partial sectional view of a refrigerator door according to the present invention;
[010] Figure 2 represents a partial perspective view of the refrigerator door of Figure lb in a first step of assembling;
[011] Figure 3 represents a partial perspective view of the refrigerator door of Figure lb in a second step of assembling;
[012] Figure 4 represents a partial perspective view of the refrigerator door of Figure lb in a third step of assembling.
[013] Figure 5 represents a partial perspective view of a particular of the refrigerator door of Figures 2- 4.
[014] Figure la shows a particular of a known refrigeration or freezer door in a schematic partial section. The door comprises an outer panel 10 and an inner liner 11, the top edges of which are connected and closed by means of a top sealing rim 12. 1 should be understood that a rim similar to the rim 12 is also provided to connect the bottom edges of the panels, so as the space delimited between said panels is closed before introducing in it the foaming polyurethane which forms the door insulation. Rims 12 are generally so shaped that their ends 13 enclose the corresponding edges of the door panels. As a consequence, the external rim ends 13 are protruding from the surface of the outer panel 10 of the door with the drawbacks already mentioned.
[015] Figure lb shows, according to the present invention, a schematic partial section similar to that of Rgμre la of a refrigeration or freezer door. Numeric references are the same for similar pieces in the two figures. In the new technical solution, the outer panel 10 shows its edge 14 which is bent toward the inside thereof and is engaged into
a corresponding groove 15 of the rim 12. 1 is apparent that the rim 12 is substantially contained within the door thickness and no projections result on the external surface of the door itself. This feature ensures also a better tightness during the insulation foaming inside the space between the outer panel and the inner liner of the door, as the rim 12 abuts against the edge 14 of the outer panel 10 and does not need special sealing means.
[016] Figures 2-4 represent, in a schematic way, respective subsequent steps for the construction of the door according to the present invention. The operation starts from an outer panel 10 which comprises a front surface 16 and lateral extensions 17. Upper and lower edges of the panel are bent toward the inside of the door body. Considering the door top, the rim 12 is introduced under the bent edge of the outer panel 10 by slanting the rim itself and pushing it to slide along the edge of the panel 10 (as shown by the arrow, Rg. 2). When the rim 12 is fully positioned under the edge of the panel, the rim is rotated in order that its groove 15 enters in engagement with the bent edge of the panel 10 (as shown by the arrow, Rg. 3). Similarly, a bottom rim is applied to the opposite end of the door panel. At the end of these operative steps, the door body is completed through the application of the inner liner 11 by eng^ing the respective edges of panels and rim (Rg. 4). Then, the polyurethane foam is let to enter into the space delimited by the panels 10, 11 and the top and^bottom rims 12, and to expand within said space, in a conventional way.
[017] I is worth noting that the lateral edges of the rim 12 are conveniently shaped in order to facilitate the operation of sliding the rim and mutual engaging between rim and panel. For this purpose, the lateral edges of the rim 12 are provided with an undercut 20 and a sloped part 21 (Rg. 2-4).
[018] Rgure 5 shows a partial perspective view of a particular feature concerning the assembly of the top rim 12 with the inner liner 11 to close internally the door body during the last part of the introduction phase for the rim 12 under the edge of the inner liner 11. For this purpose, the back edge of the rim 12 is provided on each side with a recess 18 which allows the rim to take over the edge of a rear extension 19 of the outer panel 10 and to engage the inner liner 11 against it.
[019] 1 is apparent that the features disclosed may be modified without departing from the scope of the invention. For instance, the shape of the rims 12 may be changed depending on a different profile of the panels, which can be linear or curved along their sides. Still in the same connection, the reciprocal engagement on the back side of rim 12, outer panel 10 and inner liner 11 may be obtained with a geometry different
from that before disclosed.