GB2167465A

GB2167465A - Joints in boards for floors

Info

Publication number: GB2167465A
Application number: GB08527840A
Authority: GB
Inventors: Olof R Smedberg
Original assignee: Ry AB
Current assignee: Ry AB
Priority date: 1984-11-21
Filing date: 1985-11-12
Publication date: 1986-05-29
Also published as: DK158398C; NO168196B; SE457737B; GB2167465B; DK500385D0; SE8405873D0; NO168196C; DK158398B; SE457737C; DK500385A; SE8405873L; NO854463L; GB8527840D0

Abstract

A particle board sheet for floor structures having joint means for joining the sheet to other sheets is provided. The joint means on two mutually opposite sides of the sheet have the form of a respective tongue 2 and groove 3 of corresponding cross- section, and the joint means on the two remaining sheet sides each comprises a rebate (4',4''). <IMAGE>

Description

SPECIFICATION Particle board for floor structure The present invention relates to a sheet of particle board intended for use in floor structures and presenting means for joining said sheet to other particle board sheets.

Floors of particle board mounted on underlying joist is considered to constitute construction material and is type-approved by the National Swedish Planning Authority, and the manufacture of such board is continuously monitored by the National Swedish Institute for Materials Testing. As a result, mechanical damage caused by heavy tread is practically a thing of the past. This does not mean, however, that all who live in houses fitted with particle board floors are satisfied.

Even when the sheets are laid with the greatest care and in full accordance with the laying instructions accepted by the planning office, the flooring is often disfigured by underlying sheet joins.

Evidently the glue joint is unable to prevent movement between adjacent sheets. These, probably small, movements result in permanent elongation of the floor covering over the joins.

There has been no development in particle board industry with regard to jointing technology since 1969, when the generally accepted tongue-andgroove type joint was introduced. The floor covering materials, on the other hand, have changed towards thinner, harder and more highly polished floor coverings, which although cleaned more readily have progressively less ability to take up movements in the underlying support surface.

The drawback associated with present day designs is that it is impossible in practice to lay floor board in such a way that the joints have the tight fit necessary to prevent the aforesaid joint movements.

Consequently, the object of the present invention is to provide a sheet of particle board with which tight joints can be established along both the long and the short sides thereof without rendering the task of laying the sheet more difficult.

This object is achieved in accordance with the invention by replacing the tongue-and-groove profile along two mutually opposite sides of the sheet with a rebate effective as a joining eiement.

Accordingly, the sheet according to the present invention is characterized in that the joining elements along two mutually opposite sides of the sheet comprise respectively a tongue and a groove of mutually corresponding cross-section, and in that each of the joining elements along the remaining two sides of the sheet has the form of a rebate.

The rebate is preferably cut to half the thickness of the sheet, although slight deviations in this respect can be permitted, the one cut being made to a depth slightly less than half the sheet thickness and the other cut being made correspondingly deeper.

According to one preferred embodiment the rebates are formed on the short sides of the sheet.

The invention will now be described in more detail with reference to the accompanying drawings, making apparent at the same time those advantages afforded by the invention over prior art techniques. In the drawings: Figure lisa view from above illustrating the joining of a particle board sheet with sheets already laid in a floor structure while using prior art techniques; Figure 2 is a side view of one detail of a tongueand-groove type joint according to the prior art; and Figure 3 is a side view of a detail of a joint effected with two sheets according to the invention.

Figure 1 illustrates the method of procedure when a sheet 1 is to be joined to sheets already in place in a floor structure. The sheet 1 is first moved in the direction of arrow A and is struck on the short side, so as to bring the sheet up against a previously laid sheet, in order to establish a joint therebetween. The sheet 1 is then moved in the direction B, in order to establish a tight longitudinal joint. When the joint along this short side of the sheet is tight, the friction between the two sheets will be so great as to make it impossible to move the sheet in the direction of the arrow B.

Figure 2 illustrates the established joint type, incorporating tongue 2 and groove 3. When this type of joint is used at the short end of the sheet and the sheets are joined together in the manner according to figure 1, it has been found in practice that a clearance of at least 0.5 mm is required in order to allow the sheets to be laid correctly without undue friction. This results in movement in the joints and the drawbacks associated therewith (cf.

the aforegoing).

Figure 3 illustrates a joint between two sheets 1' and 1" according to the invention. Each sheet has a joint element in the form of a respective rebate 4' and 4", and the sheets have been placed together in a manner to obtain an overlap joint. The joint is located above a joist 5 and the sheets 1', 1" are fastened thereto by means of a nail 6 passing through the joint.

By using sheets provided with rebates along the short sides thereof in accordance with the invention when laying floor structures according to Figure 1, there is obtained a joint which enables two joined sheets to be readily displaced laterally in relation to one another. When bonded and nailed or screwed down onto an underlying joist, a joint of this kind will always be tight and permit no movement.

Once having solved the problem of relative lateral displacement of the mutually adjacent sheets along the short-side joints, a tongue-and-groove profile according to figure 2 along the long sides of respective sheets can be made an absolute fit, thereby also in this case eliminating movement in the joint regions.

The restriction that the rebate joint must be placed over a supporting joist is in fact an improvement, since the Planning Authorities require short joints to lie over supporting joists. It is impossible to deviate from this requirement when using the proposed floor construction incorporating rebates at the short ends of the flooring boards.

Claims

1. A particle board sheet for floor structures having joint means for joining the sheet to other sheets, characterized in that the joint means on two mutually opposing sides of the sheet have the form of a tongue (2) and a groove (3) respectively of mutually corresponding cross-section; and in that each of the joint means on the remaining two sides of the sheet comprises a rebate (4', 4").

2.A chipboard sheet according to Claim 1, characterized in that the rebates (4', 4") are located on the short sides of the sheet.

3. A particle board sheet for floor structures constructed substantially as hereinbefore described with reference to Figures 1 and 3 of the accompanying drawings.