Panel core

Abstract

A panel core for use as the core of a panel in which folded expandable panel members are provided between partition plates, the panel members having a shape such that when the partition plates are moved apart, the panel members interengage to hold the partition plates in the expanded condition.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a honeycomb-like panel core, and more particularly to a panel core so formed that rows of core members formed by two foldable planar members can be combined in series with a partition plate therebetween.

Hitherto, in the formation of such a panel core it has been proposed to provide rows of tubular members having a circular cross-section or a polygonal cross-section which rows are united with one another through a partition plate, or to provide foldable and individual planar members united at alternate locations along their length in a honeycomb pattern or through a stiff partition plate. However, with the former type of core, it is difficult to fold the structure, and accordingly, when a section is sawed off which determines the thickness of the core for the finished panel some loss is apt to occur and the thickness itself is also apt to become uneven, and a large space is required when such a panel core is housed. With the latter type core it becomes possible to fold the core as a whole so that the drawbacks mentioned above can be avoided; however, since a disposition to return to the folded state exists at all times, the core must be held in the expanded state by applying some force from the outside at all times when it is used, for example when stiffening sheets are placed thereon to form a panel.

A primary object of the present invention is to provide a panel core which folds with ease so it can be stored or sections can be cut off, and which expands with ease when it is to be used.

Another object of the present invention is to provide a core so formed that after it has once been expanded it will remain in the expanded state without the necessity of applying thereto some force from the outside.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial perspective view of a core member formed by uniting two planar members, which core member is used for the panel core in accordance with the present invention;

FIG. 2 is a sectional view showing the state where the core members shown in FIG. 1 partially overlap one another;

FIG. 3 is a cross-sectional view showing part of the panel core according to the present invention fully folded;

FIG. 4 is a cross-sectional view showing the part of the panel core according to the present invention fully expanded; and

FIG. 5 is a perspective view, partially broken away, of a panel for which the core according to the present invention is used.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying drawings an embodiment in accordance with the present invention will be described hereinafter.

In FIG. 1, two folded planar panel members 10 and 20 are shown. Planar members 10 and 20 are made of paper, vinyl, fiber, wood or cloth. First panel member 10 has end panel portions 11 and 17 and a folded panel portion 14 therebetween having a central apex fold 14a and with the end panel portions joined to the folded portion along folds 13 and 15, and the cross-section thereof is substantially a W-shape. Second panel member 20 has end panel portions 21 and 27 joined in a cross-section of a V-shape joined at an apex fold generally indicated at 20a. Preferably there is a small inverted V-shaped portion 24 joined to the end panel portions at folds 23 and 25. A strip 12 on the outside surface of end panel portion 11 of first panel member 10 along fold 13 and a strip 16 on the outside surface of end panel portion 17 of first panel member 10 along fold 15 have adhered thereto the inside surfaces at the free ends 21a and 27a of end panel portions 21 and 27 of second panel member 20. In this manner a plurality of core members 30 are made. The size of each panel member can be selected in accordance with its intended use. However, the distance between folds 13 and 15 of first panel member 10 and the apex folds 14a of folded panel portion 14 is preferably slightly larger than that between folds 23 and 25 of second panel member 20 and lines 22 and 26 (which correspond to the positions of folds 13 and 15 against the inside surfaces of end panel portions 21 and 27).

As shown in FIG. 2, the folded panel member 20 of core member 30 is fully inserted into the space on one side of the W-shaped, panel member 10 of core member 30' which space has the same shape as the deformed V-shaped panel member with the folds 23 and 25 adjacent to fold 13 of said W-shaped panel member, namely, between end panel portion 11' and folded panel portion 14'. Alternatively it can be inserted between folded panel portion 14' and end panel portion 17'. In the same manner other core members are overlapped in turn to form a row of core members. Rows of core members thus overlapped have the outer surfaces thereof bonded to partition plates 40 with a binding agent as seen clearly in FIG. 3, and thus the panel core 1 is made.

Panel core 1 made in this matter is easy to fold, so that it is possible to cut off a portion 1 in the direction of the length of the panels 10 and 20, which cut off portion will have the desired thickness of the panel core. Panel core 1 can be expanded by pulling on both ends thereof (not shown in the drawings). Upon expanding, the portions of the panel members not adhered to the partition plates expand into the expanded panel core 1 as shown in FIG. 4. The expanded panel core 1 has a binding agent, for example, applied to the edges of the panel members and partition plates on both sides thereof, and stiffening sheets are adhered thereonto respectively to form the panel as shown in FIG. 5.

Panel core 1 described above can have the strength increased by including an appropriate synthetic resin in accordance with the material and use thereof, or by strengthening the partition plate as the occasion demands.

Moreover, in the present invention the specific portion where adhesive is applied on the outside surface of panel member 10 is assumed to be relatively narrow. However, the width of said specific portion can be optionally selected and the whole outside surface can be used as such a portion to which to bond panel member 20.

In addition, inverted V-shaped portion 24 can be formed on folded panel portion 14 of the W-shaped planar member, or it is possible to overlap core members on which inverted V-shaped portions 24 are formed on both the W-shaped panel member and the V-shaped panel member, and it is also possible to provide core members on which no inverted V-shaped portion 24 is formed, in which case folds 14 and a corresponding fold which is combined from folds 23 and 25 rest against each other in the expanded condition.

As described hereinbefore, the web core in accordance with the present invention is easy to fold and expand and yet when once expanded, it remains in the expanded state because folded portion 14 is in engagement in inverted V-shaped portion 24 and which prevents the core from returning to the folded state, so that storing, carrying, cutting, and so on can be carried out in the folded state. Therefore, these operations are very easy to carry out and the size of the core can be kept constant at all times. In addition, after being expanded it remains in the expanded state so that the bonding of stiffening sheets is very easy. In addition, the size of the spaces formed in the core is uniform, so that in respect of formation and strength the present invention is very advantageous.

In addition, the panel core in accordance with the present invention can be put to use as building materials for wall, ceiling, partition, door, sliding screen, and the like structures and also as material for furniture such as table top, wardrobe, screen, and the like structures, and others, for example, survey board, drawing board, cabinet, ping-pong table, and such structures, covering a wide field.

The web core in accordance with the present invention can be made very light in weight according to the material used and has an appropriate stiffness, and also can be stored and carried in the folded state and has at the same time the advantage which a tubular core, which is difficult to fold, has when it is in the expanded state. Also in this respect the present invention has a good effect.

Claims

I claim:

1. A panel core comprising at least one row of core members and partition plates on opposite sides of the core members in the row, each core member comprising a first panel member having a generally W-shaped cross section with end panel portions and a folded panel portion therebetween having a central apex fold and joined to the end panel portions along folds, and a second panel member having a generally V-shaped cross section with end panel portions joined at an apex fold, the free ends of the end panel portions of the second panel member being attached to the first panel member at the folds of the first panel member where the end panel portions of the first panel member join the folded panel portion of the first panel member, the outside surfaces of the end panel portions of the first panel member being secured to said partition plates, adjacent core members, in the folded condition of the panel core when the partition plates are close to each other, having the flat folded second panel member of one core member interleaved between one of the end panel portions and the folded panel portion of the first panel member of the next adjacent core member and being unsecured to each other, and in the expanded condition of the panel core when the partition plates are moved away from each other, the central apex fold of the folded panel portion of the first panel member of one core member being opposed to the apex fold of the second panel member of the next adjacent member, one of the apex folds having an inverted V-shaped portion interlocking with the other apex fold for retaining the panel core in the expanded condition.

2. A panel member as claimed in claim 1 in which there are a plurality of rows of core members, the partition plate on one side of one row of core members being the partition plate for the other side of the next adjacent row of core members.