Method of constructing insulated door

#Insulated doors for refrigerators, freezers and other insulated cabinets are usually constructed of two main components, an outer "face" and an inner "drum". The hollow chamber defined by these two members is then filled with an insulating material such as a foamed polyurethane which is poured into the chamber in liquid form and foamed in situ.

#To secure the drum to the door face the most common approach has been to use screws or bolts extending through the opposed peripheral edges of the door face and the drum. Alternatively, a bridging strip may be used where the drum and face are both made of metal and the strip may be welded to the edges of the drum and the face.

#Both of these approaches to assembling the door drum and face have a very serious drawback in that the drum and the face, that is the inner and outer surfaces of the insulated door, will be subjected to significantly different temperatures. For example, a freezer may be operated with its interior temperature at around 0.degree. F. while the outside temperature in which the freezer is located may well be 80.degree. or more. This obviously results in a thermally induced relative movement between the inner and outer surfaces of the insulated door, and, where the drum is fixed to the face by screws or other rigid fasteners, cracking and other damage to the door will often result.

#FIG. 1 is a perspective view showing an inside face of the door of the present invention;

#FIG. 2 is a cross-sectional view through the door of FIG. 1;

#FIGS. 3 through 6 are a series of cross-sectional views similar to FIG. 2, but showing the steps of constructing a door in accordance with the present invention; and

#As seen in FIGS. 1 and 2 of the drawings, a door 10 in accordance with the present invention includes an outer door face 12 of open, tray-like configuration having an outer wall 14, side walls 16 extending from the outer wall and a rim 18 extending inwardly from the side walls over the outer wall in spaced relationship thereto and terminating in an inner edge 20 defining an opening into the tray-like face 12.

#The edge 20 of the rim 18 defines an opening in the face and a drum 22 is disposed over the opening with an outer periphery 24 of the drum positioned adjacent to but spaced from opposing portions of the rim 18.

#It will be particularly noted from FIG. 2 of the drawings that the face 14 and the drum 22 together define a hollow enclosed chamber 26 and into this chamber a foamed in situ insulating material 28 is placed, substantially filling the chamber and hardening to interconnect the face and the drum.