US3385002A - Hollow core door - Google Patents

Description

United States Patent Office 3,385,fi2 Patented May 28, 1968 3,385,002 HGLLOW C(IRE [300R Edward G. Quinif, Farmington, Mich. Walled Lake Door Co., 19335 Beech-Daily Road, Detroit, Mich. 48240) Filed Mar. 14, 1966, Ser. No. 534,199 1 Claim. (Cl. 49-601) ABSTRACT OF THE DISCLOSURE The hollow core door of this invention comprises a border frame, a core within the frame, and outer panels secured to opposite sides of the frame and confining the core within the frame. The core is composed of a plurality of interconnected laths and is extended to a stressed position wherein the laths move apart to form an open cellular structure.

This invention relates to a core type construction unit and has particular reference to a new and improved hollow core door. A door according to the invention utilizes an extendable strengthening core formed from a plural y of flexible laths or slats. In the collapsed position prior to insertion within the door frame, the core laths lie flat against each other so that the core is compact and easily handled. When the core is extended and positioned Within the door frame, the laths are flexed apart so as to form a tier of lenticularly shaped support cells within the door frame. A given lath may be fitted into various size door frames by suitably flexing the lath components so that the core fills the frame. The elastically stressed slats assure that the core is properly and uniformly spaced within the frame. The sides of the lath core members and frame are secured to the side panels to complete an integral strong and durable door having high resistance to warpage or other structural deformation.

Accordingly an object of the invention is to provide a new and improved flush door.

Another object is to provide a fiush door having an improved strengthening core member.

A further object is to provide a novel cellular strengthening core for use in a construction unit.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a partially broken away perspective view of a flush door constructed according to the invention;

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1; and

FIGURE 3 is a sectional view taken along line 33 of FIGURE 1.

A flush door according to the invention includes an integral frame made up side frame members 12 and 14 and top and bottom frame members 16 and 18. Mounting blocks 20 may be secured to the inside of the frame on side frame members 12 and 14 to facilitate the mounting of latch means on the door. Side panels 22 and 24 are fitted on either side of the frame and define an interior space filled by cellular core 26.

The core is made up from a plurality of aligned elongate flexible laths or lath members 28. Depending upon the type of door or construction unit in which the core is used, the laths 28 may be made of wood, plastic, metal or other suitable material. As shown in FIGURE 1, each lath 28 is secured .at 30 to both ends of one of the adjacent laths and is secured at 32 to the middle portion of the other adjacent lath so as to form the core 26. The core 26 is usually assembled with the laths 28 lying flat upon each other. In this collapsed position the core 26 is relatively compact for ease in handling and storage.

In the mass construction of cores 26 it may be desirable to form the cores 26 from sheets of lath material having an approapriate lath width. In this case the sheets are piled one upon another and pairs of adjacent sheets are secured together at the side edges thereof as an example, with glue or other fastening means. The outer central portions of such pairs lying between the lateral edges thereof are also secured together. Individual cores are sliced from one end of the assembled sheets of lath material.

In the assembly of a flush door 10 according to the invention, the frame is first formed and then a core 26 having an appropriate width is extended and fitted within the frame by attaching the top and bottom laths to the top and bottom frame members 16 and 18. Extension of the core 26 forms a tier of lenticularly shaped support cells running from the top to the bottom of the door frame. The elastic deformation of the laths assures that the core 26 is uniformly and accurately positioned within the frame to provide a uniformly reinforced flush door 10. The flexibility of the laths also assures that laths 34 are properly seated on the ends of the blocks 20. A working clearance 36 is provided between the ends of the laths 28 and the frame side walls 12 and 14 and block 20 to facilitate insertion of the core 26 within the frame.

When the core is properly positioned within the frame, the door is completed by gluing or otherwise securing the side panels 22 and 24 to the edges of the frame and core laths, thus forming a rigid one-piece hollow flush door.

The type of core disclosed herein is particularly advantageous for use in the manufacture of flush doors since a given core can be extended, within the limits defined by the flexibility of the laths 28, to fit within various sized .door frames. This flexibility in core utility eliminates the necessity of providing a different core for each size door frame. The Strength of the door is dependent upon the number or density of support cells in the core unit. The use of a core having a large number of relatively closely spaced support cells results in a stronger door'than when a core having a smaller number of cells is used.

The drawing discloses a flush type door with a strengthening core 26 having horizontally oriented support cells extending across the width of the door. It is sometimes desirable to use a strengthening core having vertically extending support cells running from the top to the bottom of the door interior. When using such a core it is preferable to provide at least three support cells in the core in order to assure proper strengthening of the door.

It should be noted that while the invention has been described in terms of a hollow flush door construction, it is obvious that the core described herein may be used in any of a variety of construction units wherein it is desirable to strengthen the unit by means of a core member.

What I claim as my invention is:

1. A hollow core door comprising an elongated rectangular border frame, mounting blocks secured to the inner edges of the sides of said frame intermediate the ends of the latter in opposed relation to one another, a core composed of a plurality of elongated, thin generally parallel flexible laths oriented in side-by-side relation at right angles to a reference plane, each lath being secured to two immediately adjacent laths with the ends thereof secured in surface-to-surface relation to the ends of one of said adjacent laths and the center thereof secured in surface-to-surface relation to the center of the other of said adjacent laths, said core being extended from a relaxed position wherein the la hs lie fiat against each other to a stressed position. wherein the laths are moved apart to form a tier of lenticular support cells, each cell being defined by one lath and said one adjacent lath, sa d stressed core being disposed in the plane and occupying the interior of said frame with said tier running between opposed ends of said frame and said laths extending laterally between the sides of said frame, the ends of said laths above and below said blocks terminating closely adjacent the inner edges of the sides of said frame, the ends of the laths immediately above and below said blocks being flexibly seated on the ends of said blocks, the ends of said laths extending between said blocks terminating closely adjacent the inner edges of said blocks, and the uppermost and lowermost laths being centrally secured to the inner edges of the upper and lower ends respectively of said frame, and outer panels abutting and secured to opposite sides of said frame and to opposite edges of said laths.

References Cited UNITED STATES PATENTS KENNETH DOWNEY, Primary Examiner.

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