EP0016534A1

EP0016534A1 - Improvements in or relating to roof walkways

Info

Publication number: EP0016534A1
Application number: EP80300469A
Authority: EP
Inventors: Peter Gordon Mellor
Original assignee: Ferodo Ltd
Current assignee: Federal Mogul Friction Products Ltd
Priority date: 1979-02-21
Filing date: 1980-02-19
Publication date: 1980-10-01

Abstract

A walkway consists of a plurality of walkway elements (4). Each element is a plastics moulding having an upper surface provided with non-slip material and can be linked to its neighbour by a suitable method e.g. interlocks or clips.

For gutter use location points are provided on the underside of each walkway elementfor a support member, e.g. legs (5), which can be so shaped as to allow water flow in a gutter with minimum obstruction.

Description

This invention is concerned with walkways, and in particular with a walkway composed of elements moulded from plastics material.
In the building of factories the roof is commonly constructed in a form which consists of a series of ridges separated by valleys, a gutter being provided along the bottom of each valley. The roof cladding is frequently asbestos cement sheet with glass roof lights.
For maintenance purposes it is necessary for access to be gained to areas of the roof from time to time, and on such occasions the gutters form a convenient walkway across the roof, ladders being fixed to give access to the sloping areas of the roof. The gutters themselves are often constructed from asbestos-cement and are liable to damage if walked upon. Also they tend to be narrow so that a person walking in them is liable to catch his or her ankles on the edges of the roof cladding sheets.
It is therefore desirable to provide walkways across the roof to enable workmen to cross the roof without walking in the gutters, and the usual solution to this problem has been to construct wooden walkways on supports which rest in the gutters These walkways are in extensive use but have several snags. They tend to obstruct the gutters so that in storm conditions the gutters may overflow. They also rot eventually, with the result that debris falls into the gutters adding to the obstruction problem. Also, sound timber is costly and heavy so that maintenance of the walkways is an expensive and timeconsuming job, and the surface of the wood is apt to become slippery and dangerous.
The present invention aims to provide an alternative for such wooden walkways which is safe and rotproof.
It is also a problem that flat felted roofs or gutters consisting of wide troughs lined with roofing felt are liable to damage if walked upon, because of the nature of the felt and it is therefore desirable to provide a protective walkway on such a-surface.
According to the present invention there is provided a roof walkway which comprises a plurality of linked elongate elements, each said element including a tread portion comprising a single substantially rigid plastics moulding of a form providing drainage holes therein and a tread surface comprising a high friction material. Preferably each element is individually capable of being supported on one or more support members in an elevated position relative to the roof, for which purpose said tread portion has moulded into it location means for said support member.
According to the present invention also a roof walkway element includes a tread portion comprising a single substantially rigid plastics moulding of a form providing drainage holes therein, and a tread surface comprising a high friction material, and includes also location means in said Cread portion for at least one support member to support said tread portion out of a gutter.
The plastics moulding may, for example, be of a structural foam such as foamed polypropylene, and has a wall thickness and form appropriate to support the weight of persons standing and working from it.
The support member is slender in cross-section at right angles to the intended direction of the walkway, at least-, such as to allow adequate flow capacity in a gutter when in use, The support member may be'a. single moulding but is preferably detachable, and preferably a plurality of moulded legs are used, with various optional locating sockets for such legs in said tread portion. For use on a flat felted roof where little or no elevation of the walkway is required, no support member may be required, or the support member may simply be a square foot or block. Preferably, however, the walkway includes a means for attachment to the roof. If no support member is provided the lower face of the plastic moulding forming the tread portion is free of protrusions which could damage the flat roof. Means of attachment to the flat roof may be provided separately, for example metal or plastics brackets shaped to hook over the plastics moulding and be fixed to the roof.
The high friction material could be a coating on the appropriate surfaces of the tread portion, but is preferably a compounded high friction material based on an elastomeric binder with one or more abrasive fillers and used in the form of moulded inserts attached to the tread portion, or held in sockets moulded into the tread portion.
The walkway elements may be linked by means of protruding lugs locking into corresponding sockets in adjacent elements. The normal linkage is end to end, although to facilitate stable walkways of more than one element's width means may be provided for lateral linkages between elements also- Alternatively the elements may be lined by means of clips which locate in sockets moulded into one of the surfaces of the element. Such clips.may be of plastics or of metal.
It is preferred that the walkway elements are suitable for use both in a gutter or on a flat roof. Location sockets for a support member. e.g. for legs, being provided for the former purpose, and, for the latter purpose, a plastic moulding which can be laid direct upon the roof and yet which will allow drainage both laterally and longitudinally i.e. the lower face of the plastics moulding provides water passages when laid on a flat surface.
A preferred tread portion comprises a rectangular plastics moulding in the form of an inverted tray, having openings for drainage purposes, a plurality of locting sockets for support members on its underside to provide alternative positions, a plurality of sockets for friction material inserts on the upperside to provide.the tread surface, and sockets for linking purposes at the corners and the mid points of the longer sides of the moulding.
For use particularly in gutter mounting it is preferred also that the-walkway has fixing means to engage the roof and prevent movement of the walkway elements away from the roof when in use. A suitable fixing means is a bracket which can be engaged in an opening in the tread portion and with the roof, either behind the roof edge or on protrusions such as the ends of the U-bolts used to attach roofing panels to the roof structure beneath them.
Also for the gutter use it is preferred that the edges of the tread portion of the element are chamfered on their lower sides which is to rest on a roof.
The preferred support members are legs with foot portions which have a slim shape in one direction to minimise obstruction of water flow in a gutter and a wide footprint in the other direction to spread the load of the walkway along the bottom of the gutter.
The invention will now be described in more detail with reference to the accompanying drawings of which

Figures I, illustrate diagrammatically typical gutters 2 and 3 in use on industrial buildings, with a walkway element in position.
Figure 4 is a plan view of the tread portion of a walkway element in accordance with the invention
Figure 5 is a view of the underside of the tread portion of figure 4.
Figure 6 is an end view of the tread portion of figures 4 and 5.
Figure 7 is a cross sectional view of a part of the tread portion showing the form of the frictional elements inserted therein.
Figure 8 is a plan view of a channel in the tread portion for insertion of a frictional element.
Figure 9 shows the view of two sides of a leg for the tread portion and
Figure 10 is a detail view of a leg well in the tread portion together with its associated leg spindle.
Figure 11 is a diagram showing how two walkway elements are placed end to end each supported on two legs on one edge.
Figure 12 is a diagram showing a plan view several walkway elements clipped together end to end.
Figure 13 is a diagram showing a plan walkway elements clipped together to form a walkway for a flat roof.
Figure 14 is a diagrammatic side view of the walkway shown in figure 13 as viewed in direction X.
Figure 15 is a perspective view of a walkway element according to this invention.
Figures 16,are perspective views of respectively, a roof 17, 18, bracket, an interconnecting clip, a support and 19 leg and a flat roof clip all for use with the walkway element shown in figure 15.

Figure 1 shows a roof gutter arrangement in which a 60° roof elevation 1 of glass roof lights, and a 30° roof elevation 2 of corrugated asbestos cement slope down to a valley-type gutter 3. A walkway element consisting of a tread portion 4 and legs 5 is positioned with one edge of the tread portion 4 supported by the legs 5, the other supported on the 30° slope of the asbestos cement roof cladding.
Figures 2 and 3 show roofs of similar type but with two different sizes of box-type gutters 6 and 7 in place of the valley-type gutter 3 of Figure 1.
As shown in figures 4 and 5 the tread portion consists of a plastics moulding 8 with water drainage holes 9. The moulding is reinforced on its underside by transverse ribs 10 and longitudinal ribs 11 the transverse ribs also serving to provide location channels 12 for frictional elements 13 (see figures 8 and 7 respectively for detail of these). The frictional elements 13 are extrusions of T cross-section, the stem of the T being located in the channel 12, which is provided with inwardly protruding pips 14 to ensure a good interference fit.
At each end of the plastics moulding 8 are provided a connecting lug and socket to facilitate connection to the tread portion of an adjoining element of a walkway.
On the underside of the plastics moulding 8 are provided leg wells 15 into which the legs are to be located. Various alternative leg positions are provided. including an optional position at the mid-length of the moulding. A leg well is shown in detail in figure 10, and it will be noticed that two inwardly projecting ribs 16 are provided in the otherwise circular well 20 to engage corresponding grooves 17 in the stem of each leg 18 to ensure correct orientation of the leg in the well.
The legs 18 are provided with feet 19 as shown in figure 9, to spread the load on the bottom of the gutter, the feet being longer in one direction than the other as is apparent from the two side views of figure 9. The longer dimension of the foot is to be arranged along the length of the gutter, so that the foot presents minimum obstruction to flow of water along the gutter.
The lower edges of the sides of the tread portion 4 are chamfered, as shown in figure 6, in order to spread the load on the asbestos cement roof cladding when one edge of the tread portion rests on this as shown in figures 1 to 3. Clearly, if desired the walkway element may be used free-standing in a gutter with legs supporting both edges if there is sufficient room in the gutter
The walkway elements of this invention are relatively light, each being for example, about 1 metre long, are easily carried and may be laid across the roof successively from one end of the gutter, using one element as a platform from which to position the next. If desired they may be left up on the roof, but could, if desired be readily removed after maintenance of the roof had been carried out, and used again elsewhere.
Provided that the legs are made removable the elements .can be stored in a minimum of storage space, the tread portions stacking on each other, when not in use on a roof.
The legs may be moulded in plastics material, such as polyvinyl chloride, or polypropylene, although other materials could be used if so desired.
The arrangements shown in figures 12, 13 and 14 employ clips 21 to fasten together walkway elements either end to end (Figure 12) or end to end, side to side and end to side (Figure 13). An arrangement such as that shown in Figure 13 can be used as a walkway on a felted flat roof.
As shown in Figure 14 drainage can be provided on a flat roof by shaping the elements such that they allow passage beneath them both laterally and longitudinally. The elements shown in Figure 14 rest on the roof sledge fashion with only their longitudinal side portions in contact with the roof, thus assuming longitudinal drainage, and lateral drainage is provided by castellation of the longitudinal side portions which rest on the roof.
The walkway element shown in Figure 15 consists of a tread portion 25 which is a plastics moulding in the form of an inverted tray having drainage apertures 26 extending through it and strengthening ribs, both lateral and longitudinal. on its underside.
Strips of friction material 27 are provided on the tread surface, held in position by interference fit in slots in the tread portion 25.
At each corner of the tread portion 25 is an opening 28 to receive an interconnection clip 29 (shown in Figure 17), and on each long side there is a further opening 30 which may be used to receive an interconnecting clip 29 or a flat roof clip 31 (shown in Figure 19).
Also on the underside of the tread portion 25 are moulded a plurality of sockets for support legs 32 (shown in Figure 18) the form of the interior of the sockets not being visible in Figure 15 but their blind ends show on the top surface of the tread portion 25- as the portions 33. Three rows each of three sockets are provided towards both long sides of the tread portion 25 to give alternative positions for the support legs 32.
The support legs 32 as shown in figure 18 consist of a straight stem portion 34 having an approximately H-shaped cross section, and a foot portion 35 which is wider in one direction than the other and of a steamlined shape to minimise obstruction when it is used in a gutter.
The stem portion 34 may be marked at intervals as shown at 36 to facilitate cutting down to a desired length to suit a particular gutter, when using the walkway in the manner shown in figure 1. The H-shaped cross section is to enable the socket for the support leg to be provided with a lug or lugs to ensure that the stem portion 34 can be inserted into its socket with the foot portion 35 only in the correct orientation.
A suitable material for the support legs is a 10% glass filled U/V light protected polypropylene, and for the tread portion a foamed (0.7gm/ml density), U/V light protected polypropylene. The strips of friction material are preferably a compound of an oil and water resistant polymer, e.g. PVC or nitrile rubber or a mixture of both, with an abrasive filler.
The tread portion 25 shown in figure 15 is provided with a row of holes 37 at each end to permit the use of roof brackets as shown in Figure 16. A roof bracket is shown diagrammaticaly in figure 1 to illustrate its mode of use, its function being to assist in keeping the walkway in its correct position in the gutter. The roof bracket shown in figure 16 consists of a pin 38 and bent strip 39, between which there is a 90° "fir tree" type fastening. The latter permits the strip to be removed and the pin to be inserted into a hole 37 just beyond the roof edge (as shown in figure 1), the strip then being slid back onto and up the pin until it is located behind the roof edge as in Figure 1 and finally facilitates locking of the strip in that position by a 90° turn of the pin to engage the "fir tree" fastening.
In the walkway element shown in figure 15 the ratio of the lengths of the long and short sides is 2 to 1 in order to permit arrangements of several elements together, although the ratio 2 to 1 is not essential, 3 to 2 or 3 to 1 being other acceptable possibilities.

Claims

1. A roof walkway which comprises a plurality of linked elongate elements, each said element including a tread portion comprising a single substantially rigid plastics moulding of a form providing drainage holes therein and a tread surface comprising a high friction material.

₂. A roof walkway according to claim 1-in which each element is individually capable of being supported on one or more support members in an elevated position relative to the roof the tread portion having moulded into it location means for said support members.

3. A roof walkway according to claim 1 or 2 in which each element is such that when placed on a flat roof without a support member drainage of water along the roof is possible both laterally and longitudinally through the element.

4. A roof walkway according to claim 1, 2 or 3 in which the elements are linked together by means of clips engaging in recesses or apertures in said plastics mouldings.

5. A roof walkway element including a tread portion comprising a single substantially rigid plastics moulding of a form providing drainage holes therein and a tread surface comprising a high friction material, and including location means in said tread portion for at least one support member to support said tread portion out of a gutter.

6. A walkway element according to claim 5 in which said location means comprises a plurality of sockets in the underside of said tread portion to provide alternative locations for one or more support members.

7. A walkway element according to claim 5 or 6 which includes at least one support member beneath the tread portion for supporting said tread portion out of a gutter, said support member being slender in cross section at right angles to the intended direction of the walkway such as to allow adequate flow capacity in a gutter when in use.

8. A walkway element according to claim 5, 6 or 7 which includes two or more support legs having stem and foot portions and engaging sockets in the underside of said-tread portion.

9. A walkway element as claimed in any one of claims 5 to. 8 in which the tread portion comprises a single substantially rigid plastics moulding, having on its underside both lateral and longitudinal strengthening ribs and a plurality of locating sockets for support members, and having drainage holes between said ribs.

10. A walkway element as claimed in claim 9 in which said plastics moulding has a length which bears a simple ratio to its width.

11. A walkway element according to claim 9 or 10 in which the plastics moulding has at its corners apertures to receive clips to link the elements together.

₁₂. A walkway element according to claim 9, 10 or 11 in which the plastics moulding has apertures at its sides to receive fixing brackets to facilitate its being fastened to a flat roof.

₁3. A walkway element as claimed in any one of claims 9 to 12 in which castellations are provided in at leat some of the strengthening ribs to allow drainage across them along a flat roof.

14. A walkway element substantially as described herein with reference to the accompanying drawings.

₁₅. A roof walkway substantially as described herein with reference to the accompanying drawings.