GB2257940A - Forming plastics edging strips - Google Patents

Abstract

A method of shaping a plastics edging strip to include a portion for overlying a curved edge e.g. of a step includes the stops of slitting the strip 23 to provide adjacent body portions 26-28 and sequentially temporarily securing the body portions to a support 18. The portions 26-28 are curved, using heat if necessary, to follow a desired outline. Adjacent portions 26-28 are then welded together and may be coated with an adhesive layer. <IMAGE>

Description

FORMING PLASTICS MATERIALS This invention relates to the forming of plastics materials such as stair nosings, and in particular to the shaping of stair nosings to fit stairs of unusual shape.

Stair nosings are applied to the outer edges of steps for several purposes. Mainly they increase the grip of the stair adjacent its edge. In addition, by manufacture from attractive materials such as coloured plastics, with attractive inserts nosings significantly improve the appearance and attractiveness of staircases. Similar consideration applies to decorative plastics edgings in other fields.

A particular problem arises in relation to staircases in public places such as hotels, restaurants, night clubs, bars and the like. In such establishments it is not at all unusual for one or more of the lowermost steps of a staircase to extend beyond stair bounding walls or balustrades and to have one or more curved ends, or to be curved throughout their entire width. Such lower steps can be bullnose or commode steps.

Stair nosings have, heretofore, been made from extruded aluminium or plastics materials. With either of these materials the use of a straight length of nosing on a straight stair presents no installation or construction problems. In relation to a commode, or comparable non-straight step, it is very difficult to form a nosing which will fit the step accurately. The problem is particularly severe, because commode steps are very often manufactured individually to suit the particular room or staircase concerned and therefore there are very few standards.

A mould could, of course, be used to create an aluminium or plastics nosing, but a mould would only produce a nosing of a particular size. As the number of mouldings of any one size is severely restricted because of the above variety in shapes, such a mould would be uneconomic.

In relation to aluminium nosings, it is possible to shape an extruded strip to follow a curve, because of the nature of the material. Using metal beating techniques, and much time and very highly skilled labour, it is possible to shape an extruded length of aluminium to have a curved shape. However, metal beating techniques cannot be used in relation to plastics material.

It is an object of the present invention therefore, to provide a method of forming a stair nosing to fit a step which has a curved edge.

The invention provides a method of shaping a plastics edging strip which includes a body which, in use, overlies a portion of a surface, adjacent a curved edge, including the steps of slitting the body to provide a plurality of adjacent body portions, sequentially temporarily securing the body portions to the support and curving them to follow a desired outline, welding adjacent portions together whilst secured to the support and removing the formed edging from the support.

The edging can be generally flat, or can be a nosing for steps or an edging of plastics material, which has a flat portion and a depending nose, for work and other surfaces.

After welding and removal from the support the welds can be trimmed (as by grinding) to remove material outstanding from the surfaces of the body.

The body can be slit longitudinally thereof to create two or more longitudinal strips, the number of strips generated depending on the sharpness of the desired curve and the flexibility of the material of the body.

The support can be a template having one edge which mirrors the shape of the stair edge for which the nosing is intended and along which edge the nose of the nosing is disposed. Inwardly from that edge a datum can be provided for determining the position of that edge of the body remote from the nose. The datum can conveniently be in the form of an upstand.

In an alternative embodiment the body can be split in a direction transversely of the longitudinal direction of the nosing, V-shaped portions of the body being removed and the remaining portions of the body between such removed sections being individually temporarily secured to the support during bending of the nose and thereafter the portions welded together.

During bending of the portions heat can be applied to the portions so as to permit smooth bending without kinking.

Such heating can conveniently be applied by means of radiant heating, or, desirably, by means of hot gas such as air.

For temporarily fastening the body to the support any convenient means can be used. Desirably, however, the support is formed of a fastener receiving material and the portions of the body are secured thereto by removable fasteners. Nails, tacks or staples can be used, staples being preferred.

However, other temporary hold-down systems including lever arrangements; and hydraulic pneumatic or vacuum systems could be used, provided they are large in number and can be applied to individual portions of the body and will allow welding between them. As the number of such curved edgings/nosings of a particular shape to be manufactured is limited, complicated mechanical or other automatic systems are not likely to be economically viable and the use of temporary fasteners is expected to be most economic.

The support can be any convenient fastener receptive material made from natural or reconstituted timber, plastics, or any other fibrous or comparable material which will repeatedly receive fasteners, hold them, and yet allow removal. Chipboard, blockboard, sterling board, plywood and such like stable wood products have been found suitable.

The upstand for supporting either an edge of the body remote from the nose, or, in certain methods, the nose where the process is carried out in an inverted manner can be provided by a layer of thinner material secured to the support with its edge spaced from the curved edge of the support by the width of the body.

However, for large curved steps, that is to say when the step is curved along its entire length, it can be economic not to manufacture a large wooden mould, but to use a flexible upstand which can be removably secured to a support to provide a curve of a desired radius or varying in radius or curvature. This saves the necessity for creating a large template which may not be used very frequently. In such a method a pair of flexible upstands can be used on a plain base to define a curved nosing and the process carried out with the nosing inverted between the two.

If desired, a body can upstand from the support shaped and arranged to enter into a recess normally provided on the upper surface of the nosing which recess, in use, incorporates a decorative and/or non-slip insert. The use of such a body can be used to ensure that the width of the recess is not changed during the forming process.

Welding of the portions together can be carried out by use of any convenient form of heat, such as infra-red, gas or hot air. A hot air gun is preferred and if necessary, and particularly for use where appreciable gaps have been created between adjacent portions a filler rod can be used of similar plastics material.

After grinding or otherwise cleaning up, one or both sides of the welded body can be coated with a layer of stair pad adhesive. This gives additional support to the weld and gives stability, as well as filling any small voids so as to give the surface very compatible and useful adhesion to the eventual steps.

Application of the invention to edgings other than stair nosings is, of course, possible.

The invention includes, of course, a stair nosing formed by the method aforesaid.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein Fig. 1 is a plan view of a staircase having a commode step; Fig. 2 is a cross-section through a stair nosing; Fig. 3 shows a paper pattern of the commode step of Fig. 1, which will be created by the owner or the contractor; Fig. 4 shows a part of a template made from the pattern of Fig. 3 and which has a member secured thereto to form an upstand; Fig. 6 shows the support with a length of stair nosing attached; Figs. 7a to 7e illustrate varies steps in a preferred process of the invention.

Fig. 8 is an enlarged cross-sectional view on the line VIII-VIII of Fig. 7e before welding; Fig. 9 is a view similar to Fig. 8 shown after welding; Fig. 10 is a view of the curved nosing after removal from the support cleaning and the application of an adhesive layer to each side of the body.

Fig. 11 is a plan view of a second form of support; Fig. 12 is an enlarged cross-sectional view on line XII-XII of Fig. 11; Fig. 13 is a view similar to Fig. 12, but illustrating a further modification.

Referring now to the drawings, Fig. 1 shows a plan view of an end of a staircase. Three steps are shown, the lowermost of which has a generally semi-circular left-hand end and a curved right-hand end. Such a step may be referred to as a bullnose step, or a commode step.

In the application of stair nosing 12 to the steps of the staircase, there is no problem in applying straight lengths of extruded plastics nosing to steps other than the commode step 11. Fig. 2 shows the nosing 12 in cross-section and it will be seen that the nosing has a body 13, which in use overlies an outer front portion of the step and a nose 14 which overlies a front edge of the step. The body 13 has a recess 15 into which is adhered an insert 16. The colour of the nosing 12 and the insert 16 are chosen to match the decor of the establishment.

When a commode or bullnose step, such as step 11, has to be lipped with nosing, considerable problems arise in shaping the nosing to fit the curved ends of the steps. Whilst aluminium can be beaten to shape laboriously, plastics material cannot be so treated.

As commode steps come in very many shapes and sizes, moulding, or compressing lengths of the extrusion between heated formers is not economic.

In carrying a preferred method of the invention into effect a pattern 17 of paper or comparable material is prepared, for example by a contractor or owner. From the pattern 17 is made a support 18 whose outer edge 19 corresponds to the shape of stair to which the nosing must fit. It will be noticed, of course, that the pattern 17 shown in Fig. 3 is curved at both ends so as to fit the commode step 11. In the following description only one end of the nosing will be described, it being understood that the opposite end is treated in a comparable way.

The support 18 can, conveniently, be in the form of a piece of 15mm thick chipboard, plywood, timber or comparable fastener receptive material. To the top of the support 18 is secured a member 20 which provides a datum for an inner edge 21 of nosing 12.

The member 20 has an edge 22 which is spaced from the edge 19 by distance equal to the width of the body 13.

The member 20 can conveniently be made from a sheet of hardboard or the like.

Having created the support and the datum 22, the assembly of the support of member 20 is secured to a bench or like support. A length of nosing 23 is then laid in register with one edge of the assembly and secured so that a fraction 24 thereof, estimated to be ample to cover the desired curve extends beyond the assembly. The length 23 can be secured to the support 18 as by staples 24 but before such securement the body 13 is provided with a plurality of longitudinal slits 25 which extend parallel to each other and to the length of the nosing 23. For a typical nosing made from PVC and having a body some 100 mm in width, three longitudinal slits would be provided, one being relatively close to the nose 14 and the other two being spaced about 30 mm apart. For narrower nosing two slits are possible and in Fig. 6 and 7 two slits 25 are shown.

The slits 25 divide the length of nosing 23 into three adjacent portions 26, 27, 28.

In creating a bend, an inner portion 26 is heated using a hot air gun or the like and once it has just become flexible is bent around the edge 22.

Small sections of the portion 26 are dealt with individually and as the portion 26 is bent, it is secured, by staples 29, to the support 18. The staples are shown in Fig. 7a to 7d as extending parallel to the length of the portion 26. In practice, the staples would be placed where they are needed in order to ensure that the portion 26 remains flat with its underside in close contact with the support 18. The process of bending the portion 26 is continued until the situation shown in Fig. 7a is reached. Thereafter, portions 27 and 28 are bent in exactly the same way and secured by staples until the condition shown in Fig. 7e is reached. At this point it will be seen that the ends of the portions 26, 27, and 28 are staggered as shown at 30 due to their being bent around a different radii.

Fig. 8 shows how the three portions 26,27 and 28 appear after bending and stapling. At this stage, a weld is created at each join 31,32. In those places where the respective portions are close together a weld can be made simply by using a pad, for example, heated by hot gas or the like (a tool comparable to a soldering iron and operating at appropriate temperature is very suitable). Where a gap has been formed at the join 31 or 32, perhaps due to inaccurate original sawing of the slits 25, a filler rod (not shown) can be simultaneously melted and fed into the join to fill any cavity during welding.

As is shown generally at 33 and 34 in Fig. 9 (which shows the join 31 and 32 after welding) there will usually be irregularities on the top surface.

When the welds have been allowed to cool staples 29 are removed and the curved nosing removed from the support 18.

After this the nosing, welded on the "top" side, is inverted and welding carried out on the reverse of the joins 31 and 32 the "underside" to ensure that the weld is complete. At this stage the base of the recess 15 and the underside are ground or otherwise shaped to remove the irregularities caused during welding.

Thereafter, as shown in Fig. 10, each side of the body 10 and the surface of the recess 15 is coated with adhesive at 35 and 36. This has a laminating effect with the body 13 and helps to strengthen the welds. It also makes a surface compatible with the adhesive which will eventually be used to secure the nosing to a stair. In Fig. 10 the thickness of the layers of adhesive 35, 36 has been greatly exaggerated.

Referring now to Figs. 11 and 12, it will be seen that in relation to a large commode step which needs very large convexly (or concavely) curved nosing, it can be uneconomic to create a special shaped support as support 18. In this case, therefore, a baseboard 37 can be provided and a flexible upstand secured thereto as by brackets and fasteners 39 to meet the desired shape. Adjacent the upstand can be disposed a thin pad 40 of thickness and shape designed to fit within a recess 41 with an inverted length of nosing 42. In this embodiment the nosing is placed upon the set up in an inverted condition, slit along all, or substantially all, of its length, and heated and bent and secured to the baseboard 37 by staples or replaceable fasteners as aforesaid. Two or more joins 43, 44 are created in a manner comparable to the method described in relation to Fig. 7.If necessary a secondary upstand 45 can be provided for the rear edge of the nosing.

Fig. 13 shows a second way in which the upstand 38 can be used in conbination with a support 46 having an edge 47 which can be either convex or concave.

Using the arrangement shown in Fig. 13 bending of the nosing can be carried out in precisely the same way as described in relation to Fig. 7.

The invention is not limited to the precise details of the foregoing and variations can be made thereto. For example, heating of the material of the nosing can be by hot air, hot gas, radiant heat, infra-red or any other convenient form of heating. In certain circumstances a heated support may be suitable. Temporary fastening means of any convenient form can be employed and instead of the staples, fasteners such as tacks, nails, pins or even sewing in some circumstances could be used. An apertured baseboard connected to vacuum could provide a vacuum hold-down for the portions of the nosing, but such a system might be expensive and only justified where a large number of nosings needed to be shaped.

Instead of the slits being longitudinal, they could, if necessary, be formed transversely of the body of the nosing, creation of the slits taking out thin V-shaped wedges of material of the body, leaving between them portions which, when reunited by welding, form a body of the desired shape and curvature.

Of course, the invention applies to the shaping of plastics edging other than stair nosing.

In relation to plastics edging material which needs to be of a decorative nature, it will be necessary to finish the joins (at least on the visible side) to acceptable standards. Alternatively, a decorative coating, or a decorative insert could be used to mask the seams created. Although stair nosings are generally made from PVC, the method of the invention is, of course, applicable to all thermo-plastics and comparable materials.

The invention is applicable to edgings with and without noses.

Many other variations are possible within the scope of the invention.

Claims (11)

1. A method of shaping a plastics edging strip which includes a body which, in use, overlies a portion of a surface, adjacent a curved edge, including the steps of slitting the body to provide a plurality of adjacent body portions, sequentially temporarily securing the body portions to the support and curving them to follow a desired outline, welding adjacent portions together whilst secured to the support and removing the formed edging from the support.

2. A method as claimed in claim 1, wherein the edging is a nosing for steps having a flat portion and a depending nose.

3. A method as claimed in claim 1 or claim 2 whrein the body is slit longitudinally thereof to create two or more longitudinal strips.

4. A method as claimed in claim 1 or claim 2, wherein the body is slit transversely of the longitudinal direction thereof and V-shaped portions of the body are removed so that the remaining portions of the body between such removed sections form the adjacent body portions.

5. A method as claimed in any preceding claim whrein the support is a template.

6. A method as claimed in any preceding claim wherein heat is applied to the body portions during curving thereof.

7. A method as claimed in any preceding claim wherein the support is formed of a fastener receiving material and the body portions are temporarily secured to the support by means of removable fasteners.

8. A method as claimed in any preceding claim wherein one or more upstands is provided on the support, such upstand being removably or otherwise secured to the support.

9. A method as claimed in any preceding claim wherein a body upstands from the support, said body being adapted to enter a recess provided on the upper surface of the edging, said recess, in use, incorporating a decorative and/or non-slip insert.

10. A method as claimed in any preceding claim wherein one or both sides of the welded body is coated with a layer of adhesive.

11. An edging or stair nosing formed by a method as claimed in any preceding claim.