Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Shaping against forming surface
Reexamination Certificate
2000-06-26
2004-02-10
Safavi, Michael (Department: 3673)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Shaping against forming surface
Reexamination Certificate
active
06689301
ABSTRACT:
The disclosed invention is to a method for manufacturing a molded door skin from a wood composite material, as well as the resulting skin and the door produced therefrom. More particularly, the disclosed invention is to a method for manufacturing a molded door skin in which a solid blank sheet of wood composite material is heated in a press to a temperature sufficient to soften the blank, after which the press platens are pressure actuated to close and the pressure thereafter cyclically increased to thereby deform the blank into a molded configuration suitable for a door skin and ultimately for being assembled into a door.
Hollow core doors are used in both interior and exterior applications. A hollow core door may be a flush door, that is one flat or planar on both major surfaces. Alternatively, the hollow core door may be a “molded” door, that is one having a series of three dimensional panels formed into the skins as they are being manufactured. Molded door skins are relatively expensive, because the capital cost is quite high due to the need for dies, presses, and the like. The skins used for flush doors, on the other hand, are relatively inexpensive, but they do not provide the aesthetic features sometimes required by consumers.
Many hollow core doors are made from door skins formed from wood composite materials. These wood composite materials may include particle board, flake board, hard board and medium density fiber board (“MDF”). The wood composites utilize a resin binder, which frequently is a thermal setting resin, in order to maintain the wood fibers forming the composite in solid form. The wood composites are not moisture impervious, so doors utilizing such skins may not be suitable for exterior applications. Should the composite material absorb moisture, whether in liquid or gas form, then the door components may swell and the door distort. Fiberglass and steel doors do not have the same moisture absorbing tendency, and hence are more frequently used for exterior applications.
Because of the cost differential between a wood composite flush skin and a wood composite molded skin, attempts have been made to transform flush skins into molded skins. Those prior efforts have not resulted in a commercially acceptable door skin, principally because the appearance of the surface is not satisfactory. Prior efforts to transform a flush skin into a molded skin have generally resulted in a skin having a cracked, marred, or otherwise aesthetically unpleasing configuration and appearance.
Standard molded door skins are formed from a relatively thick mat or bat of material, which is thereafter compressed in a press to a relatively thin thickness. The mat is dry in the case of MDF or has a very high water content in the case of hard board, with the result for the latter that the water is squeezed out during the pressing operation. Because the mat is in a very flexible state during the pressing operation, then the resulting skin has sharply defined features acceptable to consumers because the wood fibers can flow in order to conform to the mold. Due in part to the high capital costs involved to create molded skins, the manufacturer frequently requires that an individual order be for a large number of skins in order to permit maximum operating efficiencies. Smaller orders become cost prohibitive.
Those skilled in the art will recognize that there is a need for a method of manufacturing a molded door skin from a wood composite which permits a standard flush skin blank to be used as the base material, and which results in a molded door skin having the features and surface characteristics acceptable to consumers. Yet a further need in the art is a door manufactured from wood composite door skins, which has suitable resistance to moisture so that the door may be used for exterior applications. The disclosed invention meets these and other needs in the art.
A primary object of the disclosed invention is a method for manufacturing a door skin from a wood composite blank through cyclically applying an ever increasing pressure to a softened blank, so that the resulting skin has the features and surface characteristics acceptable to consumers.
A further object of the invention is a door skin which is impervious to moisture, with the result that the door will not distort and therefore will be suitable for exterior applications.
A method of manufacturing a door skin, according to the invention, comprises the steps of providing a wood composite flat blank. The blank is placed between the platens of a heated press, with the platens being heated to a temperature sufficient to soften the resin in the blank and to thereby soften the blank; Sufficient pressure is applied to close the platens, and thereafter the pressure is cyclically applied at increased levels for thereby causing the blank to be deformed into a molded shape determined by the configuration of the platens. The molded blank is then removed from between the platens.
A door skin, according to the invention, comprises a molded medium density fiber board three dimensional blank. The blank has a first portion with a first pre-selected thickness. The blank has a second portion with a second preselected thickness. The second thickness is less than the first thickness.
A door skin, according to the invention, comprises a molded medium density fiber board three dimensional blank having a density of about 800 to about 1,000 Kg/m
3
.
A door, according to the invention, comprises a peripheral frame having oppositely disposed sides. First and second molded skins are provided. Each skin has first and second sides. Each first side of each skin has a moisture impervious barrier applied wholly thereabout. Each of the door skin second sides is secured to one of the frame sides.
These and other objects and advantages of the invention will be readily apparent in view of the following description and drawings.
REFERENCES:
patent: 3112243 (1963-11-01), Egerstrand
patent: 3900334 (1975-08-01), Brink
patent: 4007076 (1977-02-01), Clarke et al.
patent: 4146662 (1979-03-01), Eggers et al.
patent: 4201802 (1980-05-01), Vande Kieft
patent: 4236365 (1980-12-01), Wheeler
patent: 4265067 (1981-05-01), Palmer
patent: 4301187 (1981-11-01), Burch
patent: 4517147 (1985-05-01), Taylor et al.
patent: 4606388 (1986-08-01), Favot
patent: 4684489 (1987-08-01), Walter
patent: 4828004 (1989-05-01), Martinez et al.
patent: 4830929 (1989-05-01), Ikeda et al.
patent: 4844968 (1989-07-01), Persson et al.
patent: 5000673 (1991-03-01), Bach et al.
patent: 5008057 (1991-04-01), Risius et al.
patent: 5085891 (1992-02-01), Evans
patent: 5183622 (1993-02-01), Persson
patent: 5219634 (1993-06-01), Aufderhaar
patent: 5306539 (1994-04-01), Clarke et al.
patent: 5505772 (1996-04-01), Charazipour et al.
patent: 5782055 (1998-07-01), Crittenden
patent: 6079183 (2000-06-01), Moyes
patent: 6500372 (2002-12-01), Frankefort et al.
patent: 0420831 (1991-04-01), None
patent: 0688639 (1995-12-01), None
patent: 454073 (1936-09-01), None
patent: 1154241 (1969-06-01), None
patent: 1420244 (1976-01-01), None
patent: 2237531 (1991-05-01), None
patent: 2276902 (1994-10-01), None
patent: 2306541 (1997-05-01), None
patent: 2324061 (1998-10-01), None
patent: 54-093077 (1979-07-01), None
patent: 55-042804 (1980-03-01), None
patent: 57-049550 (1982-03-01), None
patent: 58-024433 (1983-02-01), None
patent: 62-264916 (1987-11-01), None
patent: 03-284912 (1991-12-01), None
patent: WO8702407 (1987-04-01), None
patent: WO 87/05955 (1987-10-01), None
patent: WO 96/03262 (1996-02-01), None
PCT International Search Report, PCT/US98/07003.
Liniak, Berenato & White, LLC
MDF Inc.
Safavi Michael
LandOfFree
Method of manufacturing a molded door skin from a wood... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing a molded door skin from a wood..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing a molded door skin from a wood... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3345452