IE44344B1 - Improvements in or relating to panels - Google Patents

Abstract

1524734 Coating panels all-round with thermoplastics J LAWRENCE T W AYRE and S RICHARDSON [trading as PRE-SEAL ROOFING CO] 7 Feb 1977 [7 Feb 1976] 04855/76 Headings B2E and B2L [Also in Division B5] A stress bearing building panel comprises a stress-bearing panel with an impervious thermoplastic material completely coating both faces and all the edges; typically it is capable of being walked on, is made of plywood or particle board, and the moisture-impervious thermoplastic material is bitumen; the panel may be 8' x 4'. It may have a layer of roofing felt bonded to one face thereof. Panels 11 are driven by nip rolls 15 to be coated by hot bitumen from hopper 19 and also by bitumen applied from tank 23 by roller 24; this co-acts with roller 21 to spread bitumen on the faces of the panel so as to overflow the edges; the "sides" of the panel are coated by the effect of doctor blades downstream of the rollers; the "ends" are coated by momentarily reversing drive rolls 15 to create a gap between adjacent panels, into which gap bitumen flows. A felt 27 may be immersed in bitumen 28 and fed as shown to be laminated to a panel by roller 21.

Description

The present invention concerns stress-hearing building panels, a method of making such panels, and apparatus for making such panels.

The stress-bearing panels with which the invention is 5 concerned are stress bearing in the sense that they can be walked on and are used for decking panels for, say, flat or generally horizontally disposed roofs, such as garage roofs.

They are typically four.by eight foot panels of particle board or plywood to be applied to the joists of structures to be covered and then protected in turn by one or more layers of roofing felt. There is frequently a long delay in applying the felt and the panels can become water-logged and have to be replaced. Even if not water-logged, they are often damp when the felt is applied and the felt is often lifted by the internal vapour pressure spoiling the appearance of the roof.

For this reason it has been proposed to bond felt to the panels before they are applied to the joists but it is often difficult, to ensure the edges of the panel are protected. Such felt is \ of course only on one face which is intended to be the exposed face.

According to the present invention,, there is provided a stress bearing panel comprising a stress hearing board (as herein defined) with an impervious material - 2 4 1 3 4 d completely coating both, faces and all the edges.

By impervious material is meant a material substantially impervious fo water and water vapour and pin-holes of a small size are not significant. This material is applied in a fluid state and is preferably a thermoplastic substance which is sti when hot such as bitumen or a citumenous compound. Normal commercial grades of bitumen include extenders such as flint dust or other fine quartz typically a fifty-fifty mixture cf bitumen with the quarts.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in vzhich : Figure 1 is a schematic axial section through apparatus for making the panels, Figure 2 is a plan detail of the apparatus of Figure 1, Figure 3 is a detail taken on line IT - III of Figure 2, and Figure A is a schematic detail showing the coating of the end of the panels.

A stack of particle boards 11 in a rising feed hopper <'not shown) are fed singly onto a conveyor 17 to form a line of pan travelling lengthwise through the apparatus. The conveyor comp· rises a number of idler rollers or wheels 14· and a pair of pinch rollers 15 for driving the boards along the conveyor. When on the conveyor, the boards are taken through a treatment station 17 and then discharged into an outlet hopper 18.

The treatment station comprises a hot bitumen hopper 1y discharging hot bitumen down a regulated chute 20 onto the upper surface of each board as it passes underneath and an idler roller 21 to spread the bitumen over the upper surface _ 5 _ ahd causing it to overflow the edges of the board, doctor blades 22 to smear the overflowing bitumen along the longitudinal edges, and a further hot bitumen tank 23 below che board from which a layer of het bitumen is transferred to the underneath of the board by a transfer roller 24. To prevent pick-xro of the bitumen by the conveyor rollers or wheels downstream of the station, these rollers or wheels are preferably kept wet. To prevent the building panels sticking together in the outlet hopper, the upper surfaces of the.panels can be dusted with a stickiness-killing powder such as talc. The doctor blades are resilient so as to conform to slight variations in ths widths of the boards. To coat the ends of the boards, when the abutting ends of two boards aro sufficiently far into the treatment station for the bitumen welling up before the roller 21 as shown in Figure 4 to cover· the join, the drive to the pinch rollers 15 is momentarily reversed, automatically or manually to create a gap into which the bitumen is forced by the roller 21 vihich gap is then closed up again tc give a good end coating. The pinch rollers are of course positioned sufficiently close to the treatment station as to engage the board following the one being treated. The conveyor can be arranged to speed up the treated panels and prevent them sticking together end to end but normally this will not be needed.

A layer of felt can be applied to the upper surface. This can he bought-out roofing felt but it is preferred to use saturated felt (which is similar to roofing felt but does not have an outer layer of coating bitumen). Fibre mat 2? is fed through a hot impregnating vat 28 containing bitumen from which the saturated fibre mat is taken through a device 29 which a _ removes surplus bitumen and then over guide rollers 30 onto the roller 24 by which it is applied to the boards sticking th to by virtue of the bitumen on the boards. The felt layer is cut manually or automatically to separate the panels.

Claims (9)

1. Ί. A srress bearing Building panel comprising a stress bearing beard . (as herein defined) with, an impervious thermoplastic material completely coating both faces and. all ths edges.

2. . A panel according to claim 1 wherein the material is bitumen.

3. A panel according to claim Ί or claim 2 further having a layer of felt on one face thereof.

4. A method of making a panel according to. any one of the preceding claims wherein the impervious material is applied to a stress bearing board on both faces thereof and spread over those faces and wherein the spreading operation causes some of the material to overflow the edges where it is smeared to form a continuous coating thereon.

5. Apparatus for making stress bearing building panels comprising a support for a line of stress bearing boards with means of separating adjoining boards to cause a small gap between those adjoining boards means for applying and spreading an impervious thermoplastic material in a hot liquid state on both faces thereof, this applying and spreading means being arranged to cause some of the material to overflow onto the edges, means for imparting movement of the line of boards relative to the applying and spreading means, and means for spreading the material overflowing onto the longitudinal edges along those edges.

6. Apparatus according to claim 5 wherein the applying and spreading means comprises a means for dispensing a measurea amount of the material on the upper face and a roller for spreading the material over the upper face, and a transfer - 6 roller for applying and spreading a coating of the material or. the lower face, the dispensing means dispensing an amount of the material such that the upper face spreading roller will cause some of the material to overflow the longitudinal edges and also into the said small gap between adjoining boards and wherein doctor blades are disposed on the longitudinal edge to smear the overflowing material therealong.

7. Apparatus according to claim 5 or claim 6 wherein the separating means comprises a reversing device in the means for imparting relative movement such that the board following the one being treated is effectively pulled back to create the said small gap. S. Apparatus according to any one of claims 5 to 7 further comprising a vat with means for guiding a fibre mat through the vat to be saturated therein with impervious material and then onto the panels.

8.

9. A method substantially as described with reference to the accompanying drawings.

40. Apparatus substantially as herein described with reference to the accompanying drawings.