US 3299595 A
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Description (OCR text may contain errors)
Jan. 24, '1967 E. MUNK COMPOUND DOOR Filed July 12, 1963 ll llol lllllrlllll 1K & QM g F W W D T E A United States Patent 4 Claims. (a. 52-309 The present invention relates to a compound door which consists of a profiled and partly plastic-covered frame or members of such a frame which is molded of a mixture of a comminuted organic fibrous material, for example, wood chips, and a thermosetting binder, of an inner structural part intermediate the side parts of the frame which is preferably made of the same material as the frame, and of panels of a thin sheetlike material which cove-r the opposite sides of the inner structural part and are glued to this part and also to the frame and may, if desired, also be coated with sheet plastic.
Although compound doors are known in which the frame of the door consists of solid wood, there are no such frames known upon which a layer of sheet plastic is molded. Moreover, it is practically impossible to mold thermosetting plastics directly upon solid wood. There are also no solid wood frames known which are profiled in such a manner that the paneling sheets of the door are sunk into undercut grooves in the frame which are made, for example, of a dovetailed shape. In most compound doors with solid wood frames, the paneling sheets are glued to both sides of the entire outer surfaces of the frame, and if the frame is to be provided with a recess along the outer edges of the door frame, this continuous recess is milled into the wood frame after the entire door has been assembled and glued together. The internal structure of such a door, for example, in the form of ahoneycomb pasteboard construction is always separate from the frame and glued to the panel sheets. Since the wood frame of such a compound door is paneled only along its flat outer sides, the recessed or unrecessed outer edges of the frame are not covered and willeven if painted or enameled-not give a uniform optical appear ance since the different materials of the frame, i.e. the solid wood and the panels, have different technological properties and the edges of these different materials will show through the enamel coating. Such a compound door has the further disadvantage that the recesses and apertures for the lock and keyhole and the hinges cannot be cut into the door frame until the door is otherwise completed and finally milled to size. Finally, the solid wood fr-ameof such a door always works, i.e. it swells and shrinks, resulting in warping of the entire door. Such warping is aggravated by the fact that the different parts of the door, i.e. the frame, the interior structure, and the panels, have different swelling and shrinking properties and work relative to each other. This is one particular reason why compound doors of this type of construction, even though originally made quite accurately, will often later close improperly. Furthermore, because of these different properties, it often occurs that the interior structure will in the course of time become marked on the outer surface of the paneling. Although some of these disadvantages and the constantly prevailing danger of cracks forming in the solid wood may be reduced to some extent by making the frame of a carefully selected wood which is properly dried and free of knotholes, this renders such a door very expensive.
The principal objects of the present invention are to provide a compound door which overcomes all of the above-mentioned disadvantages of the previous compound doors employing solid wood frames, does not warp, may
be produced more quickly and inexpensively, and has a much better and better lasting quality and appearance than the previous compound doors.
These objects are attained according to the invention especially by molding at least the frame of the door under heat and pressure of a mixture of comminuted organic fibrous materials, for example, wood chips, and a thermosetting binder to its final desired size and shape, and by then coating all of the outer visible surfaces of the frame including the outer recessed or unrecessed edges thereof with a layer of plastic or plastic-impregnated sheet material. The size and shape of the door according to the invention is therefore exactly predetermined so that, after its completion, no additional work either manual or by machines has to be carried out thereon,
regardless of whether the door is to fit flush into the stationary surrounding frame or whether its edges are to be recessed. The apertures and recesses for the lock, keyhole, and hinges are preferably molded into the frame or they may be cut into the molded door frame before the door as such is completed. Since the door frame may be molded to its final size and shape in one operation, this also means that the recess along its outer edges as well as any grooves, projections, or recesses for decorative purposes may be formed in the same molding operation. Another feature of the new door frame is that a part of the opposite outer sides of the frame members is provided with molded-in recesses for receiving the door panels and that the edges of these recesses may also by molding be undercut to any desired crosssectional shape to receive the edges of the door panels. Such undercut edges of these recesses have the advantage that, when the door panels are to be glued to the frame and its interior structure, these panels may be sprung into these undercut recesses and will be gripped thereby in the proper position. The edges of the panels are then preferably beveled to a shape in accordance with the undercut recesses. This has also the advantage that, if the door panels are also coated with sheet plastic, the danger is avoided that the plastic layers might separate along its edges from the paneling sheets. Furthermore, due to the undercut-ting, the coated or uncoated panels will be held tightly in the frame independently of the gluing and they may be fitted so tightly into the recesses that no visible seam will appear between the coated parts 6 of the frame and the door panels.
The frame may either be molded as one integral body without any joints or it may be assembled of several mitered parts. Although the interior structure of the door may also be molded separately from the frame and then be secured to the inner sides thereof, it is preferable to mold it together with the frame, that is, in the same molding operation. For a mass production of doors of different heights or different widths it isalso possible according to the invention to mold the interior structure integrally with two opposite frame members, the ends of which are beveled either by cutting or molding, and then to complete the door by mitering the two other frame members to the first frame members. In this case, the interior door structure is preferably not directly connected to the last two frame members, but only subsequently through the glued-on paneling sheets. The interior structure of the door is designed primarily for the purpose of making the door as light and inexpensive as possible, but also to provide a sufficiently strong base upon which the door panels may be glued. It is therefore preferably made of a corrugated, honeycomb, or any other shape which insures that there are an adequate amount of contact surfaces upon which the door panels may be firmly glued in a manner so that the points of connection between the internal door structure and the paneling will not be marked and noticeable on the outer surfaces of the latter. The pressure which is applied upon the door panels when they are being glued upon the interior structure should therefore not be excessive but in proportion to the number and size of the contact surfaces of the interior structure. The door panels whether plain or coated on the outside with sheet plastic may also be made very economically and of the exact size so as to fit properly into the undercut recesses in the frame even before they are being glued into the frame and the contact surfaces of the interior door structure.
A very important feature of the compound door according to the invention is that, whereas in plastic-coated doors with wood frames of prior designs those parts of the doors which are especially subjected to stresses, namely, either all of the visible parts of the frame or at least the edge portions thereof are not plastic-coated, the present invention provides that all of these parts are so coated without seams. Therefore, all of the visible parts of the frame including the recessed or unrecessed edge portions are more resistant to wear and easily cleaned. Also, since the coating according to the invention consists of a thermosetting sheet plastic which is molded under heat and pressure upon the frame or its parts, it combines intimately or even integrally with the frame since the latter also contains a thermosetting plastic. It is quite obvious that such a plastic coating will adhere to its base, the molded frame, much more securely and permanently than a sheet of plastic which is merely glued to its base, namely, a solid-wood frame.
The above-mentioned features and advantages of the present invention will become further apparent from the following description thereof which is to be read with reference to the accompanying drawings of two different embodiments thereof, in which FIGURE 1 shows a cross section which is taken along line 11 of FIGURE 2 and shows a compound door with recessed outer edges and an internal structure of a corrugated shape;
FIGURE 2 shows a plan view of the same door;
FIGURE 3 shows a cross section which is taken along line 3-3 of FIGURE 4 of a compound door with plane outer edges and an internal structure of a honeycomb shape; while FIGURE 4 shows a plan view of the door according to FIGURE 3.
As illustrated in FIGURES l and 2 of the drawings, the compound door according to the invention consists of a molded outer frame 1 which is provided with recesses 2 in its lateral outer edges and with recesses 3 for receiving the paneling 4 upon which, if desired, also a layer of sheet plastic 5 may be molded or glued. According to the invention, the inner edges 6 of the recesses 3 are undercut and the outer edges of the paneling are similarly beveled so as to fit tightly into the undercut edges 6. The space which is surrounded by the door frame 1 is bridged by an internal structure 7 which consists of a continuous molded web of the same material of which the frame itself is made, namely, of a mixture of a comminuted organic fibrous material, for example, wood chips, and a thermosetting plastic. Although this internal structure 7 may be molded to its desired shape in an operation separate from the operation of molding the frame 1, it is preferable to produce both parts, the frame and the internal structure, in one molding operation so that the two parts are integrally connected to each other. The entire visible parts of the frame from one edge 6 to the other edge 6 are coated by a continuous layer 8 of a thermosetting sheet plastic or plastic-impregnated material which is molded thereon without seams.
' Whereas the entire door frame 1 including the interior door structure 7 according to FIGURES 1 and 2 consists of one integral piece in which even the corners 9 of the different sides of the frame are integrally connected without joints, FIGURES 3 and 4 show a modification of the invention, in which only two opposite frame members 10 are molded integrally with the interior structure 11, while the two other frame members 12 are separately molded, and then connected to the frame member 10 by mitered joints 13. The beveled edges for these mitered joints 13 may either be produced by molding or they may be cut in the conventional manner. Since the interior structure 11 is sufiiciently secured to the frame by being molded to the two opposite frame members 10 and subsequently also to all frame members 10 and 12 by being glued to the panels 14, it is not necessary also to secure the interior structure 11 directly to the frame members 12. This embodiment of the invention has the advantage that it permits a mass production of doors of different lengths or widths. The frame members 10 together with the interior structure 11 may then be made of a considerable length and may then be divided to form the main bodies of several doors. The frame of each of these doors is then completed by securing the other frame members 12 to the beveled ends of the frame members 10 to form the joints 13. Thereafter, the panels 14 which again may be plain or coated with sheet plastic 15 or the like are glued upon the end surfaces of the interior structure 11 and to the uncoated surfaces 16 of all frame members 10 and 12 which again are preferably provided with undercut edges 17 into which the beveled edges of the coated or uncoated panels 14 are fitted. In the embodiment according to FIGURES 3 and 4, the outer edges 18 of the door frame are plane and not recessed as in FIGURES 1 and 2, but they are likewise coated with a continuous layer 19 of sheet plastic or plastic-impregnated material which reaches from one edge 17 to the other.
The interior structure may be of any desirable shape, as long as its contact surfaces 20 or 21 are sufficiently large and sufiiciently close to each other so that the panels 4 or 14 may be securely glued thereto. Thus, the interior structures may be made, for example, of a corrugated shape with fiat outer contact surfaces 20, as shown in FIGURES 1 and 2, or of a honeycomb shape, as shown in FIGURES 3 and 4, which are likewise provided with flat contact surfaces 21.
Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.
Having thus fully disclosed my invention, what I claim is:
1. A compound door, comprising: molded spaced apart frame members and integrally connected molded internal structure spanning the space between said frame members; said frame members and internal structure being molded from a mixture of comminuted organic fibrous material and a thermosetting plastic; a recess molded into the opposite sides of each of said frame members; paneling members adhered to each side of said internal structure and completely covering the opposite sides thereof and secured to said frame members by extending the lateral edges thereof into said recesses; and a coating of sheet material containing a thermosetting plastic molded to and completely covering all outer parts of said frame members up to the lateral edges of said paneling members.
2. A compound door in accordance with claim 1 wherein said recess that is molded into the opposite sides of each of said frame members are provided with a beveled surface and the lateral edges of said paneling members are provided with complementary beveled surfaces together with longitudinal recesses formed in the lateral edge of each of said outer frame members.
3. A compound door, comprising: molded spaced apart frame members; a molded internal structure integrally connected with two opposite members of said frame and being unsecured to the other tWo members of said frame; the ends of said opposite members of said frame and the other two members of said frame being beveled and mitered together; said frame members and said internal structure being molded from a mixture of comminuted organic fibrous material and a thermosetting plastic; recesses molded into the opposite sides of each of said frame members; paneling members adhered to each side of said internal structure and completely covering the opposite sides thereof and secured to said frame members by extending the lateral edges thereof into said recesses; and a coating of sheet material containing a thermosetting plastic molded to and completely covering all outer parts of said frame members up to the lateral edges of said paneling members.
4. A compound door in accordance with claim 3 wherein said recesses are provided with beveled surfaces and said lateral ends of said paneling members are provided with complementary beveled surfaces to interfit within said recesses.
References Cited by the Examiner UNITED STATES PATENTS 2,033,884 3/1936 DavisOn 49400 2,090,480 8/ 1937 HaWley 52627 2,214,675 9/1940 Jensen 52615 2,220,596 11/ 1950 Bernhardt 52-618 2,569,902 10/1951 Rienau et al 52-456 2,593,050 4/1952 Paul et al. 52232 2,602,204 7/1952 Rizza 161-68 2,765,056 10/1956 Tyree 49399 2,931,746 4/1960 Wilson et a] 260869 X Primary Examiner.