Door

Abstract

The present invention relates to a door capable of preventing the door from being warped or bent and also from being damaged due to the penetration of moisture. The door of the present invention comprises front and rear panels which define front and rear surfaces of the door, respectively; a pair of horizontal frames which are fixed to upper and lower ends of the front and rear panels between the front and rear panels, respectively; and a pair of vertical frames which are fixed to right and left ends of the front and rear panels between the front and rear panels, respectively. Each of the vertical frames includes an inner frame which is fixed to an innermost position and made of wood, a middle frame which is fixed to an outer side of the inner frame and made of metal, and an outer frame which is fixed to an outer side of the middle frame and made of a synthetic resin. Further, a foaming agent is filled in an inner space formed between the front and rear panels by the frames to form a foam layer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a door, and more particularly to a door configured so that deformation due to an external force can be avoided by forming frames of a synthetic resin, wood and metal materials and then forming a foam layer between the frames.

2. Description of the Related Art

A currently mass-produced door generally uses a synthetic resin to form its frame. However, in a case where the frame is made of only a synthetic resin, there is a problem in that the door is warped as a whole. For example, in a region where temperature difference between inside and outside of a door is great, the door is warped to give a bad influence on the product reliability.

To compensate for the bad effect, a door frame may be made of a synthetic resin and reinforced wood. However, if it is used for a long time, the frame may be damaged due to moisture penetrated into a wood portion thereof. For example, if paint or coating agent on the door surface is striped off due to long-time use, external moisture is penetrated into the wood. Thus, there is a problem in that it substantially gives a bad influence on life and reliability of the door itself.

In addition, although the reinforced wood is also used, there is limitation in strength reinforcement of the door itself. That is, since wood has limited strength, it is not satisfactory enough to prevent the wood from being warped due to an external force as described above.

SUMMARY OF THE INVENTION

The present invention is conceived to solve the aforementioned problems in the prior art. Accordingly, an object of the present invention is to provide a door having relatively improved strength.

Another object of the present invention is to provide a door with excellent heat insulation effects.

A further object of the present invention is to provide a door with minimized moisture penetration from the outside.

According to an aspect of the present invention for achieving the objects, there is provided a door comprising: front and rear panels defining, respectively, front and rear surfaces of the door; a pair of horizontal frames fixed, respectively, to upper and lower ends of the front and rear panels between the front and rear panels; and a pair of vertical frames fixed, respectively, to right and left ends of the front and rear panels between the front and rear panels, wherein each of the vertical frames comprises an inner frame which is fixed to an innermost position and made of wood, a middle frame which is fixed to an outer side of the inner frame and made of metal, and an outer frame which is fixed to an outer side of the middle frame and made of a synthetic resin, and wherein a foaming agent is filled in an inner space formed between the front and rear panels by the frames to form a foam layer.

Preferably, the front and rear panels are made of either a synthetic resin or glass fiber.

More preferably, the middle frame is made of aluminum.

More preferably, the middle frame is formed to have an I-shaped section or the middle frame is formed to have a C-shaped section.

More preferably, the horizontal frame is made of a synthetic resin.

More preferably, upper and lower ends of the vertical frames are installed between the pair of the horizontal frames.

More preferably, the inner frame of the vertical frame is made of an LVL (Laminated Veneer Lumber) in which a plurality of sheets of plywood are laminated and attached one above another, and the plurality of sheets of plywood are attached in a right and left direction.

More preferably, grooves are formed on front and rear ends of the middle frame, respectively, in a longitudinal direction thereof; and protrusions are formed on the front and rear panels, respectively, to be fitted into the grooves.

According to the present invention so configured, there are advantages in that the door may be prevented from being warped or bent in a fore and aft direction due to an external force caused by temperature difference between the inside and outside of the door and also from being damaged due to the penetration of moisture. Further, since the heat insulation in the building can be maximized, energy saving effects can also be expected.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view showing a door according to the present invention;

FIG. 2 is a sectional view showing an end of the door according to the present invention;

FIG. 3 is a sectional view showing an end of the door according to another embodiment of the present invention; and

FIG. 4 is a sectional view showing an end of the door according to a further embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings As shown in FIG. 1, a door of the present invention includes front and rear panels 10 and 20 that define its front and rear surfaces, respectively. The front and rear panels 10 and 20 may be made of a synthetic resin and are formed to be relatively thin. The front and rear panels 10 and 20 may be made of any kinds of synthetic resins only if they can define a surface while having predetermined strength as well as preventing moisture from being penetrated.

Further, it is most preferred that the front and rear panels 10 and 20 be formed by hot pressing a glass fiber in consideration of their strength. However, the front and rear panels 10 and 20 are not necessarily limited to the glass fiber in view of their materials, but they may be made of any kinds of synthetic resins or glass fiber-reinforced synthetic resins. The front and rear panels 10 and 20 have the substantially same shape as each other and have any shapes or patterns on their surfaces.

Along edges between the front and rear panels 10 and 20 are installed a pair of horizontal frames 30a and 30b and a pair of vertical frames 50a and 50b. A pair of the horizontal frames 30a and 30b are horizontally installed at upper and lower ends of the front and rear panels 10 and 20, and substantially define the upper and lower ends of the door, respectively. Further, the horizontal frames 30a and 30b may be made of a synthetic resin, preferably of a synthetic resin with sufficient strength, if possible. The horizontal frames 30a and 30b have the same entire horizontal length as that of the front and rear panels 10 and 20.

In addition, in a case where the horizontal frames 30a and 30b are made of a synthetic resin, the frames may have strong resistance against moisture penetration. However, the horizontal frames 30a and 30b may also be made of reinforced wood, similarly to the vertical frames as described later.

The vertical frames 50a and 50b of this invention define right and left frames of the door. The vertical frames 50a and 50b define vertical edges at both lateral sides of the door in a state where they are interposed between the horizontal frames 30a and 30b. That is, upper and lower ends of the vertical frames 50a and 50b are preferably supported on the horizontal frames 30a and 30b in a state where they are brought into contact with a bottom surface on right and left side ends of the upper horizontal frame 30b and a top surface on right and left side ends of the lower horizontal frame 30a. According to this configuration, an inner frame 52 of the vertical frame 50a or 50b, which is made of wood, is covered with the horizontal frames 30a and 30b such that a wood portion of the door cannot be exposed to the outside. Therefore, the present invention has an advantage in that the door has strong resistance to the penetration of moisture.

A pair of the vertical frames 50a and 50b of the present invention are installed at the right and left positions sides of the door and have the substantially same shape as each other. Therefore, the following description will be given only on the basis of the vertical frame 50a that is positioned right as viewed from the figure.

The vertical frame 50a of the present invention includes an inner frame 52 that is installed at an innermost position and made of wood, a middle frame 54 that is brought into contact with the external side of the inner frame 52 and made of metal, and an outer frame 56 that is installed to the external side of the middle frame 54, i.e. the outermost position.

The inner frame 52 is preferably formed of wood with such strength that the complete door cannot be warped due to an external force. To this end, the inner frame 52 is preferably made of wood having sufficient strength in a front and aft direction to prevent the door from being deformed in the fore and aft direction (i.e., toward or away from the inside of door) in a state where the door is standing upright. For example, an LVL (Laminated Veneer Lumber) in which a plurality of sheets of plywood are laminated and attached one above another is preferably used as the inner frame 52. As shown in FIGS. 1 to 3, this LVL is installed to provide significant structural strength against the fore and aft bending of the door since the plurality of sheets of plywood are laminated and attached one after another in a lateral direction (i.e., in a right and left direction) of the door.

In addition, the middle frame 54 is formed of a metal material to provide sufficient structural strength against the fore and aft bending of the door. The middle frame 54 can be generally made of a metal material with excellent strength. The middle frame 54 may be shaped as a flat pate as shown in FIG. 1 or formed to have an I-shaped or C-shaped section as shown in FIGS. 2 and 3. More preferably, the middle frame 54 is made of aluminum among the metals, in consideration of lightweight characteristics, structural strength, improved forming quality and the like.

The outer frame 56 is preferably made of a synthetic resin to completely prevent moisture from being penetrated into the door from the outside. Further, it is apparent that the outer frame 56 may also be made of a synthetic resin containing wood powder or other additives. The outer frame 56 may be mainly made of a material capable of preventing moisture from being penetrated therein, i.e. a synthetic resin, but may be additionally made of other materials in consideration of strength and surface texture thereof.

A term “synthetic resin material” as used herein means including both a material composed of synthetic resin only and a material containing synthetic resin as a main component and other additives such as wood powder as described above.

As explained above, the vertical frame 50a is composed of the inner frame 52, the middle frame 54 and the outer frame 56. The inner frame 52, the middle frame 54 and the outer frame 56 are attached to one another by means of an adhesive to be formed into a complete vertical frame 50a or 50b as a whole.

FIG. 2 is a sectional view of an end portion of the assembled door according to the present invention. As shown in this figure, it can be understood that the vertical frame 50 is installed at an edge between the front and rear panels 10 and 20. The vertical frame 50 is composed of the inner frame 52 made of wood, the middle frame 54 made of metal, and the outer frame 56 made mainly of synthetic resin, which in turn are integrally attached to one another by means of an adhesive.

Further, in the embodiment illustrated in FIG. 2, the middle frame 54 is formed of a metal material with an I-shaped section. The outer and inner frames 56 and 52 attached from the outside of the middle frame 54 with an I-shaped section have vertical grooves at front and rear ends thereof such that the outer and inner frames 56 and 52 can be completely and easily fastened to the middle frame 54 with an I-shaped section.

Furthermore, in the embodiment illustrated in FIG. 3, it will be understood that the middle frame 54 made of a metal material, preferably aluminum, is formed to have a C-shaped section, even though the other elements are the same as those in the previous embodiment. In FIG. 3, the elements other than the middle frame are the same as those as in the embodiment shown in FIG. 2 and are designated by the same reference numerals, respectively.

In addition, FIG. 4 is a sectional view of an end portion of the assembled door according to another embodiment of the present invention. As shown in this figure, the middle frame 54 of this embodiment has grooves 54a at front and rear ends in a vertical direction, such that protrusions 10a and 20a formed on the front and rear panels 10 and 20 can be fitted into the grooves 54a. The grooves 54a are formed vertically along the front and rear ends of the middle frame, and the protrusions 10a and 20a are also formed to extend in the vertical direction. Since the protrusions 10a and 20a are inserted into the grooves 54a on the front and rear ends of the middle frame 54, respectively, it is substantially ensured that the door can be conveniently assembled and the assembled door can be firmly prevented from being deformed. In this embodiment, the elements other than the middle frame 54 are the same as those in the previous embodiment.

As described above, if the middle frame 54 is made of a metal material and also formed to have an I-shaped or C-shaped section or with the grooves at front and rear end thereof, it can be substantially easily fastened to the inner or outer frame from the lateral sides thereof. Further, since a sufficient contact area is ensured, the frames can be more easily integrated. Furthermore, if the middle frame 54 is made of the metal material and also has an I-shaped or C-shaped section, it can provide greater structural strength against the fore and aft rearward bending of the door.

As described above, if the pair of horizontal frames 30a and 30b and the pair of vertical frames 50a and 50b are assembled at the edges between the front and rear panels 10 and 20, the assembled frames have an empty space at the center thereof. In such an empty space, a foaming agent is filled to form a foam layer. The foam layer can serve to reinforce the strength of door and provide better heat insulation property. In FIGS. 2 and 3, a foam layer 60 is shown as being formed in the door. Further, to form such a foam layer 60, a foaming agent should be injected into the empty space in a state where the frame assembly is positioned in an additional mold while the foaming agent is filled into the empty space of the door such that the front and rear panels and the respective frames can sufficiently withstand a foaming pressure.

In addition, if the foaming agent is filled into the door to completely form the foam layer 60 as mentioned above, the door can be completely manufactured by finishing the exterior of the door. This finishing process may include the steps of cutting upper and lower ends of the door at accurate sizes and spraying a predetermined stain on the door surface for the surface treatment.

After the stain is sprayed on the door surface, the surface on which the stain has been sprayed may be polished with a soft fabric and the like to further provide a three-dimensional effect to a design or pattern formed on the front and rear panels 10 and 20. This polishing work allows the stain to be uniformly distributed at uneven portions of the panels, thereby sufficiently expressing the three-dimensional effect. Further, after the stain has been sprayed and dried, a predetermined coating agent is sprayed on both surfaces of the door to complete the door.

The door of the present invention so configured has sufficient structural strength by means of the middle frame 54 made of metal (e.g., aluminum) in addition to the inner frame 52 made of wood. In particular, the middle frame 54 can provide structural strength enough to prevent the door from being warped frequently at regions where the temperature difference between the inside and outside of a room is extremely large.

In addition, since the outer frame 56 is made mainly of a synthetic resin capable of preventing moisture from being penetrating into the door, it is possible to prevent the moisture penetration, and thus, the damage of door.

According to the present invention described above, the following advantages can be expected.

First, since the vertical frame of the door is provided with the middle frame made of metal (e.g., aluminum), there is an advantage in that the door is very strong against the fore and aft bending thereof. Therefore, since the door can sufficiently withstand an external force caused by the large temperature difference between the inside and outside of a room or an unexpected external force applied from the inside and outside of the door, it is possible to prevent damage of the door such as bending or warping, and thus, to further improve the product reliability.

In addition, the prevention of damage such as the bending or warping of the door means that a gap is not substantially generated between the frames, and thus, the heat insulation effect can be maximized. Therefore, it can be further understood that the door of the present invention is very useful in view of energy saving effect.

Furthermore, since the outer frame and the horizontal frame are made mainly of a synthetic resin and these frames also define the entire exterior of the door, there is an advantage in that the door is sufficiently strong against the moisture penetration.

It will be apparent that those skilled in the art can make various modifications and changes within the scope of the fundamental technical spirit of the present invention. Accordingly, the scope of the present invention should be construed on the basis of the appended claims.

Claims

1. A door, comprising: front and rear panels defining, respectively, front and rear surfaces of the door; a pair of horizontal frames fixed, respectively, to upper and lower ends of the front and rear panels between the front and rear panels; and a pair of vertical frames fixed, respectively, to right and left ends of the front and rear panels between the front and rear panels, wherein each of the vertical frames comprises an inner frame which is fixed to an innermost position and made of wood, a middle frame which is fixed to an outer side of the inner frame and made of metal, and an outer frame which is fixed to an outer side of the middle frame and made of a synthetic resin, and wherein a foaming agent is filled in an inner space formed between the front and rear panels by the frames to form a foam layer.

2. The door as claimed in claim 1, wherein the front and rear panels are made of either a synthetic resin or glass fiber.

3. The door as claimed in claim 1, wherein the middle frame is made of aluminum.

4. The door as claimed in claim 1, wherein the middle frame is formed to have an I-shaped section.

5. The door as claimed in claim 1, wherein the middle frame is formed to have a C-shaped section.

6. The door as claimed in claim 1, wherein the horizontal frame is made of a synthetic resin.

7. The door as claimed in claim 1, wherein upper and lower ends of the vertical frames are installed between the pair of the horizontal frames.

8. The door as claimed in claim 1, wherein the inner frame of the vertical frame is made of an LVL (Laminated Veneer Lumber) in which a plurality of sheets of plywood are laminated and attached one above another, and the plurality of sheets of plywood are attached in a right and left direction.

9. The door as claimed in claim 1, wherein grooves are formed on front and rear ends of the middle frame, respectively, in a longitudinal direction thereof; and protrusions are formed on the front and rear panels, respectively, to be fitted into the grooves.