Spacer for hollow-core structures

Abstract

This spacer for paneled hollow-core doors has an H-beam configuration, with a first flange connected along its length to a second flange along its length by a web. The web is perpendicular to both the first and second flanges. A hollow-core door is assembled by placing the spacer between two door skins. Once the door is assembled, the web is parallel to the door skins. To accommodate the variation in distance between the bottom and top skins that is created by the raised panels, the bottom edge of each flange has one or more bottom notches that fits closely over the raised portion of the panel in the bottom skin and one or more top notches that fits closely over the raised portion of the panel in the top skin. Preferably only two or three spacers are used in a paneled door, each spacer extending the length of the door.

Claims

1. A spacer for installation between a top skin that is parallel to a bottom skin of a hollow-core structure to keep a top skin spaced apart from a bottom skin, the spacer comprising: a. a first straight flange having a length and a first notch made therein to accommodate a raised panel in the bottom skin; b. a second straight flange having a length and a second notch made therein to accommodate the raised panel in the bottom skin; c. a web connecting the first straight flange along its length to the second straight flange along its length, wherein the web is: i. perpendicular to the first straight flange and the second straight flange; and ii. parallel to the top skin and bottom skin.

2. The spacer of claim 1 wherein the cross section of the spacer has an H-beam configuration.

3. The spacer of claim 1 wherein the first straight flange, second straight flange, and web are made of fiberboard.

4. The spacer of claim 1 wherein the web is connected to the first straight flange and second straight flange with glue or other adhesive.

5. The spacer of claim 1 wherein the spacer has a length at or near the length of the bottom skin.

6. The spacer of claim 5 wherein: a. the top skin has at least one raised panel; and b. the first straight flange and second straight flange have notches made therein to accommodate the raised panel in the top skin.

7. The spacer of claim 1 wherein the hollow-core structure is a door and the spacer is inside the door.

8. A spacer for a hollow-core structure having a top skin, a bottom skin, a frame separating the top skin and the bottom skin to form a hollow space between the skins in order to keep the top skin spaced apart from the bottom skin, the spacer comprising: a. a first flange having a length and a first notch made therein to accommodate a raised panel in the bottom skin; b. a second flange having a length and a second notch made therein to accommodate the raised panel in the bottom skin; c. a web connecting the first flange along its length to the second flange along its length, wherein the web is perpendicular to the first flange and second flange and parallel to the bottom skin.

9. The spacer according to claim 8 wherein the first flange has notches made therein to accommodate one or more raised panels in the bottom skin.

10. The spacer of claim 8 wherein the cross section of the spacer has an H-beam configuration.

11. The spacer of claim 8 wherein the first flange, second flange, and web are made of fiberboard.

12. The spacer of claim 8 wherein the web is connected to the first flange and second flange with glue or other adhesive.

13. The spacer of claim 8 wherein the spacer has a length at or near the length of the bottom skin.

14. The spacer of claim 13 wherein: a. the bottom skin and top skin each have at least one raised panel; b. the first flange and second flange have notches made therein to accommodate the raised panel in the bottom skin; and c. the first flange and second flange have notches made therein to accommodate the raised panel in the top skin.

15. The spacer of claim 1 further comprising: a. a third straight flange having a length and a third notch made therein to accommodate the raised panel in the bottom skin; b. a second web connecting the third straight flange along its length to the second flange along its length, wherein the second web is: i. perpendicular to the third straight flange and the second straight flange; and ii. parallel to the top skin and bottom skin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 (PRIOR ART) is a top view of the inside of the bottom skin of a paneled door with rigid block spacers.

(2) FIG. 2 (PRIOR ART) is a perspective view of a rigid block spacers of FIG. 1 comprising a stack of sheets of corrugated cardboard stacked and glued together.

(3) FIG. 3 (PRIOR ART) is a perspective view of a spacer having a crossmember perpendicular to the lengthwise axis of the elongated member and perpendicular to the skin.

(4) FIG. 4 is a perspective view of one embodiment of the H-beam spacer of the present invention with no notches.

(5) FIG. 5 is a perspective view of another embodiment of the H-beam spacer of the present invention with notches.

(6) FIG. 6 is a top view of the inside of the bottom skin of a paneled door with spacers of the present invention.

(7) FIG. 7 is a cross-sectional view of the spacer along line 6-6 of FIG. 5 installed between door skins.

(8) FIG. 8 is a side view of a portion of a spacer of the present invention.

(9) FIG. 9 is a perspective view of another embodiment of the H-beam spacer of the present invention with no notches.

(10) FIG. 10 is a perspective view of another embodiment of the H-beam spacer of the present invention with notches.

(11) FIG. 11 is a perspective view of the end of a solid panel with a spacer of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(12) The present invention solves the problems of the prior art with a spacer that is made with only a relatively small amount of material, glue, and labor. Referring now to FIGS. 4-11, the present invention is a spacer 10 having an H-beam configuration. That is, the cross section of the spacer looks like an uppercase letter H. A first flange 11 is connected along its length by a web 30 to a second flange 21 along its length. See FIGS. 4 and 5. The spacers of the present invention are explained generally the in context of a hollow-core door, but may also be used in other hollow-core structures, such as tabletops, kick plates, privacy panels for desks, shelves, mantles, and the like.

(13) The first flange 11 and second flange 21 are elongated members oriented parallel to each other and held at a uniform distance apart by the web 30. The flanges 11, 21 are rigid in at least the z-axis and when installed are oriented perpendicular to the door skins. The spacers 10 can be made at or near the desired finished length, for example at or near the length of the inside space, which is the length of the door skins minus the space taken up by the rails. For example, the spacer 10 would be about 77 for a 80 tall door or about 93 for a 96 tall door, This avoids having to later break the spacers into shorter pieces, saving time, labor, and re-work.

(14) The web 30 is a rigid crosspiece and is perpendicular to both flanges 11, 21. Thus, when the spacer 10 is in place between the skins, the web 30 is oriented parallel to the door skins. The web 30 is rigid in at least the x-axis between the flanges to keep the flanges spaced apart the width of the web 30. See FIG. 4. Typically the web 30 is attached to the flanges 11, 21 at the flanges' midline, so that the portion of the flange above the web 30 is about the same as the portion of the flange below the web.

(15) The flanges 11, 21 are typically made of corrugated fiberboard with the openings in the flutes visible along the top edge 15 and bottom edge 16. That is, the flutes are parallel to the z-axis. See FIGS. 4 and 5. Typically the web 30 is also made of corrugated fiberboard with the flutes running parallel to the y-axis. See FIGS. 4 and 5. The long edges (not shown) of the web 30 are attached to each flange where the web and flange intersect. Typically the web is attached to the flanges by glue, paste, tape or other adhesive, but may be attached by alternative means such as by sonic welding, staples, or interleaving such as that used with wine bottle separators used in wine case boxes. Alternatively, the flanges and the web may be made of wood, plastic, metal or one or more other lightweight materials that are rigid in at least one direction so that the flanges can support the skins apart and the web can hold the flanges apart. The flanges and web may be corrugated or non-corrugated, solid or have openings. In some embodiments, the spacers 10 are extruded so that the flanges and web are integral, as opposed to being separate pieces that are attached to each other. The spacers may be used with hollow-core structures that are made of wood, paper, fiberboard, metal, plastic, laminated materials, insulation board, MDF or any panel material.

(16) To accommodate the variation in the distance between the bottom and top skins created by the ridges and mesas of the raised panels, the bottom edge 16 of flanges 11, 21 has one or more bottom notches 14 that fit over the ridges 40 and raised panels in the bottom skin. Top edge 15 of flanges 11, 21 has top notches 14 that fit under the ridges 40 in the top skin. FIGS. 5, 7, 8 and 10 shows notches 14 in the top edges 15 and bottom edges 16 of the flanges. Each notch in the first flange 11 has a parallel counterpart notch in the second flange 21. Given that raised panels 8 are typically of uniform shape and size on both sides of a door, the notches 14 in the top edge 15 are also typically symmetric with the notches 14 on the bottom edge 16. However, it is contemplated that one side of the door may be planar, with no raised panels. In such case the bottom edge 16 of flanges 11, 21 may have notches while the top edge 15 of flanges 11, 21 do not need notches, although they may still be present.

(17) Each notch 14 can be a different depth d.sub.n and width w.sub.n to accommodate the depth d.sub.p and width w.sub.p of each raised panel 8. See FIGS. 7 and 8. Preferably each notch 14 fits snugly against apex or mesa of the raised panel 8, so that the raised panels 8 rest snugly on the notches and the spacer 10 supports the skins 7, 17 apart at a uniform distance along the entire length of the spacer 10. That is, preferably the depth of the notch d.sub.n is the same as the depth of the raised portion d.sub.p, and the tolerance is near zero for optimum crush strength of the hollow-core door. See FIG. 8.

(18) Each notch 14 may similarly fit snugly against the ridge 40, but in other cases each notch 14 may be wider than the ridge 40 is long to accommodate size differences or location inaccuracies where the panels are formed, relative to the length of the door. Preferably, each notch 14 is as wide as or wider than the raised panel 8 so that there is some tolerance between the width of the notch 14 and the width of the raised panel, which makes installation easier. The width of the notch w.sub.n does not need to have tolerances as tight as the depth of the notch d.sub.p to maintain optimum crush strength. FIG. 7 shows the effect of having notch widths w.sub.n wider than the width w.sub.p between the raised panel portions, where there are gaps g between the spacer 10 and the door skins 7, 17.

(19) To build the door, glue is applied to bottom edge 15 of the spacer 10, typically by spraying or rolling the glue along the open ends of the flutes that will rest on the bottom skin 7. The glue-covered portions of the spacer 10 are placed on the inside surface of a bottom door skin 7, with the flanges perpendicular to the skin and the cross stroke of the letter H parallel to the skin. Typically the spacers are applied parallel to the long axis of the door, as shown in FIG. 6. More glue is applied to top edge 16 of the spacer 10, again typically by spraying or rolling the glue along the open ends of the flutes that the top skin 17 will rest on. The top skin 17 is placed on to on top of the glue-covered spacers, forming the door with the hollow interior. In a preferred embodiment, glue is put on the entire top and bottom edges 15, 16, including on the sloped and bottom edges of the notches 14. In this way the door skins are attached to the flanges along the entire length of the spacers, adhered to both base and raised portions of the door skins. In another embodiment, glue is applied to both the top and bottom edges of the spacer before the spacer is placed on the bottom skin 7. This embodiment is particularly suited to assembly using robotics, which can move quickly and accurately enough to avoid over application of the glue and quickly enough to avoid the glue drying out before assembly is complete. In yet other embodiments, the glue is applied to the interior sides of the skins, as opposed to applying it to the spacers.

(20) The present spacer 10 is made of significantly less paper than existing spacers, which reduces cost and weight. The present spacer 10 also requires less glue than existing spacers, also reducing cost. And, the present spacer is easier to install than existing spacers, reducing labor and re-work.

(21) Preferably at least two spacers 10 are installed in a hollow paneled door. See FIG. 6. A first spacer 51 is placed over the left column of raised panels 8 and glued in place. A second spacer 52 is placed over the right column of raised panels 8 and glued in place. Optionally a third spacer 53 is glued to the skin between the columns of raised panels 8.

(22) A second embodiment of the invention adds multiple flanges parallel to the first and second flanges 11, 21, to form a connected series of H-beams. See FIGS. 9 and 10, where a third flange 31 and fourth flange 41 of the series are shown. FIG. 11 shows a perspective view of the end of a solid panel, such as a bookshelf, with a spacer of the present invention. The spacer 10 is sandwiched between two panels 60 and two edge supports 61.

(23) While there has been illustrated and described what is at present considered to be the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.