GB2206634A

GB2206634A - A step member for a vertical surface eg wall of manhole

Info

Publication number: GB2206634A
Application number: GB08715546A
Authority: GB
Inventors: Christopher John Cawte
Original assignee: CASWICK DEV Ltd
Current assignee: CASWICK DEV Ltd
Priority date: 1987-07-02
Filing date: 1987-07-02
Publication date: 1989-01-11
Anticipated expiration: 2007-07-02
Also published as: GB2206634B; GB8715546D0

Abstract

The step member comprises an elongate foot support element 1 provided at each end with a leg 2, 2'. Each leg has at its free end an anchoring plug 3, 3' formed by a core 6 which is longer along a first transverse axis Fig 3. namely the axis which is vertical when the step member is in position for use, than along a second transverse axis (X Fig. 3) which is perpendicular to the first axis. The core carries a plurality of spaced-apart transverse ribs 7 which have substantially the same dimension along both said axes, the size of the core and the size of the ribs along the first axis being substantially identical. <IMAGE>

Description

A STEP MEMBER The invention relates to a step member comprising a foot support element and two spaced apart carrler elements or legs each of which is at one end firmly associated with the foot support element and at its other end provided with anchoring means or a plug adapted to be retained in a supporting structure, such as a wall, particularly a wall of a manhole.

Step members of the described kind are known in various forms which are generally satisfactory but each of which has some disadvantages known to persons skilled in the art.

The aim of the present invention is to devise a step member which avoids or at least mitigates some of these disadvantages, particularly a step member with better and safer anchoring means.

The invention will now be described, by way of example, with reference to the accompanying dIagrammatic drawings, In whlch: Fig. 1 is a plan of a step member according to the Invention, Flg. 2 shows a carryIng element in section along lire II-II in Fig. 1 turned through 90 along its axis Z, Fig. 3 is a section along line III-III in Fig. 1, Fig. 4 shows a step member in perspective, and Fig. 5 is a detail of an outer end portion of a carrying element in perspective vIew.

As is apparent from Fig. 1 the illustrated step member comprises an elongate foot support element 1 provided at the ends with carryIng elements or legs 2, 2' extending substantially perpendicularly thereto and provided at their fwee erds remote from the foot support element 1 with anchoring means or plugs 3, 3' and thelr outer edges with s,de walls 4, 4' extendIng above their upper surface. The upper surface of the element 1 is provided with a relief patters 1A which, together with the walls 4, 4' serves to retaIn the foot of the user on the step.

The step members is made of plastics material which may be solid or foamed and may comprise a filler, such as fibre-reinforced plastics. A suitable material is nylon or polypropylene. In the plastics material is embedded an integral, substantially Ushaped reInforcIng element 5 made e.g. of steel, or no-ferrous member produced by die casting. A suitable reinforcing element may also be made of expanded metal of a particular form which has the advantage of cheapness and slightness.

The legs 2, 2' are identical (except at thel parts assoclated with the foot support element 1 where they are mirror images of each other) and consequently only one of them will be dIscussed, namely the leg 2. As is apparent from the drawings the leg 2 has a longitudInal axis Z, which Is substantIally perpendicular to the longItudinal axis A of the foot support element 1. In the section shown in Fig. 3 the leg 2 has also two transverse axes parallel to the axis Z, namely an axis X, which is substantially parallel to the axis A of the foot support member 1 and axis Y which is perpendicular to the axis X.As is further apparent from Fig. 3 the metal element 5 is substantially rectangular in cross-section, its longer dimension extending in the direction of the axis Y.

The plug 3 comprises a core 6 the dimension of which is longer along the axis Y than along the axis X. In the illustrated example the core 6 is substantIally obround in cross-section, I.e. has the shape of a rectangle, the shorter sides of which are formed by semi-circles. The core 6 could have a different shape, it could be e.g. elliptical, as long as the condition is met that its dimension along the axis Y is longer than its dimension along the axis X.

The core 6 carries a plurality of circular ribs 7 spaced from each other along the axis Z. In the illustrated embodiment the ribs 7 are of uniform thickness and are spaced through uniform distances.

The outermost rib 7 merges into an end piece, in the illustrated embodiment a frusto-conlcal tip 8.

As is further apparent from Fig. 3 the diameter of the circular ribs 7 corresponds to the dimension of the core 6 measured on the axls Y. As a consequence, when a step member according to the inventIon is in a position for use, i.e. Its foot support element 1 extends horizontally, the Y-axis of each plug extends vertically i.e. in the dIrection of gravity. Each plug is therefore solid in the vertical direction and rIbbed, i.e. deformable only laterally. From this arrangement follow various advantages some of which will be mentioned below.

In order to flx a step member according to the invention two parallel holes are drilled in a wall the spacing of which corresponds to the spacing of the axes Z, Z' and the diameter of which is slightly smaller than the diameter of the circular ribs 7. The tips 8 are then inserted Into the holes and the step member is driven in until the plugs 3, 3' are fully received in the holes.

One of the advantages of the ribs is that the plugs are easier to fit in an interference fit hole. If the interference fit were along the whole cvoss-sectXor. and the whole length of the plugs, the plugs would be difficult to fit. In the speciflc arrangement of the ribs described any tolerance is taken from the side which is also advantageous that any debris from the hole can collect between the ribs and does not damage the plug or interfere with its fitting.

Step members according to the invention may be fitted in a pre-fabricated structural element, such as a tubular manhole section, during its manufacture, either in that the plugs are simply pushed into the material of the structural element while it Is still soft or the (or each) step member is held in position within the mould and material of the structural element is poured in until the plugs are fully embedded thereIn. In either of these methods no holes need to be drilled and moreover the soft material enters the gaps between. the ribs so that on hardenIng of the material the plugs are flrmly held therein.

It will be appreciated that the described plugs 3, 3' need not form part of a step member but may be used Independently as wall plugs.

Claims

CLAIM

1. A step member comprising an elongate foot support element provided at each end with a leg, each leg having at its free end an anchoring plug formed by a core which is longer along a first transverse axis, namely the axis which is vertical when the step member is in position for use, than along a second transverse axis which is perpendicular to the first axis, the core carrying a plurality of spaced-apart transverse ribs which have substantially the same dimension along both said axes, the s ze of the core and the size of the ribs along th first axis t-eing substantially identical.

2. A step member accordin to Claim 1 whe ein the core is substantially oblong. in cross-snction an the ribs are substantially circular in c-css- section.

A stp member according to Claim 1 or 2 wherein the ribs are spaced through uniform distance.

4. A step member according to any one of the preceding Claims wherein the ribs are substantially of a uniform thickness.

A A step member according to any one of the preceding Claims wherein the outermost rib merges into a substantially frusto-conical tip.

6. A step member according to any one of the preceeding claims, wherein the member is made of plastics material with metal re-inforcement.

7. A step member according to Claim 1 substantially as herein described with reference to, and as shown, in the accompanying drawings.