GB2285235A

GB2285235A - Attaching a rung of a ladder to the ladder stile

Info

Publication number: GB2285235A
Application number: GB9424663A
Authority: GB
Inventors: James Brian Clarke
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-12-08
Filing date: 1994-12-07
Publication date: 1995-07-05
Also published as: GB9325103D0; GB9424663D0

Abstract

A method of attaching a hollow rung 1 of a ladder to a stile 4 of the ladder. The rung 1 is inserted through a hole 3 in the stile and is then expanded on both sides of the stile 4 forming a bulge 11 on each side of the stile thereby securing the rung 1 in place. Corrugations 2 on the rung 1 allow the bulges to be formed without significantly stretching the rung fabric. <IMAGE>

Description

METHOD OF ATTACHING A HOLLOW RUNG OF A LADDER TO A STILE OF THE LADDER The present invention relates to a method of attaching a hollow rung of a ladder to a stile of a ladder.

To attach a hollow rung to a stile of a ladder requires two stages of manipulation of the rung material.

Firstly, a shoulder is formed near each end of the rung by either locally expanding or reducing the rung section. The rung is then inserted into a hole in the stile with the shoulder acting as a stop. Secondly, the projecting free end of the rung is swaged to form a lip to retain the rung in place. Swaging entails considerable stretching of the fabric of the rung, which, to avoid splitting, imposes limitations on the shape and the hardness of the rung.

According to a first aspect of the present invention, a method of attaching a hollow rung of a ladder to a stile of the ladder comprises inserting the rung through a hole in the stile, and subsequently expanding the rung on both side of the stile to form a bulge on each side of the stile to secure the rung to the stile.

This method can be done as a one stage process thereby speeding up manufacture. As no swaging is involved, the limitations on the shape and hardness of the rung are lessened.

The rung is preferably expanded using a tool having a circumferentially extending groove which is aligned with the wall of the stile, and the tool is subsequently forced against the inside wall of the rung.

The tool could be vibrated to expand the rung, or, if the rung was substantially circular with a cog shaped inner profile, and the head was of similar, but slightly mismatched shape, the tool could be rotated to throw the wall of the rung outwardly. However, the simplest way of expanding the rung is to use a tool formed of a plurality of segments which are forced apart by a wedge shape member to expand the rung.

In order to reduce the stresses on the rung material when it is expanded, the rung can be provided with corrugations which extend in the longitudinal direction of the rung at the region of the rung which is expanded. The corrugations are preferably intermittently disposed and around the rung.

This feature forms a second aspect of the present invention defined in its broadest terms as a hollow rung for a ladder, the rung being provided adjacent to an end, at a portion which is to be expanded during assembly with a stile, with corrugations which extend in the longitudinal direction of the rung.

The rung can be used with the method according to the first aspect of the present invention, or in a conventional method of assembling a ladder, in which case the corrugations would be provided on the part to be swaged.

The corrugations provide a surplus of material which allows the rungs to be deformed without significantly stretching the fabric of the rung. The corrugations are preferably intermittently disposed around the rung.

An example of a rung and stile constructed using the method of the present invention and incorporating the rung of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic front view in partial section showing part of a rung and a stile with a tool inserted; and Fig. 2 is a side view corresponding to Fig. 1.

The rung 1 shown in Figs. 1 and 2 is hollow and has a substantially trapezoidal transverse profile which is initially constant along its length. Longitudinally extending corrugations 2 are formed intermittently around the rung 1. The rung 1 is shown with its end inserted into a hole 3 in a stile 4, the hole being shaped to match the substantially trapezoidal shape of the outer surface of the rung 1.

A tool 5 is shown inserted into the end of the hollow rung 1. The tool 5 comprises a head 6 which has a profile to match the substantially trapezoidal shape of the inner surface of the rung. The head 6 has a peripheral groove 7 and consists of four longitudinally extending segments 8 which are mutually separable in a transverse plane. Each of the segments 8 is provided with an inwardly facing wedge shape surface 9. Between these wedge shape surfaces 9 a wedge 10 is inserted.

In order to secure the rung 1 to the stile 4, the rung is first inserted into the hole 3 in the stile to the desired extent. The tool 5 is then introduced into the interior of the rung 1 so that the groove 7 is aligned with the stile 4. The wedge 10 is then pulled or pushed into the head 6 so that the four segments 8 of the head are transversely separated. This causes bulges 11 to be formed in the rung 1 on either side of the stile corresponding to the positions on either side of the groove 7.

Claims

1. A method of attaching a hollow rung of a ladder to a stile of the ladder, the method comprising inserting the rung through a hole in the stile, and subsequently expanding the rung on both sides of the stile to form a bulge on each side of the stile to secure the rung to the stile.

2. A method according to claim 1, wherein the rung is expanded using a tool having a circumferentially extending groove which is aligned with the wall of the stile, and the tool is subsequently forced against the inside wall of the rung.

3. A method according to claim 2, wherein the tool is formed of a plurality of segments which are forced apart by a wedge shape member to expand the rung.

4. A method according to any one of the preceding claims, wherein the rung is provided with corrugations which extend in the longitudinal direction of the rung at the region of the rung which is expanded.

5. A method according to claim 4, wherein the corrugations are intermittently disposed around the rung.

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

7. A hollow rung for a ladder, the rung being provided adjacent to an end, at a portion which is to be expanded during assembly with a stile, with corrugations which extend in the longitudinal direction of the rung.

8. A rung according to claim 7, wherein the corrugations are intermittently disposed around the rung.

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