AU632929B2

AU632929B2 - An improved stepladder

Info

Publication number: AU632929B2
Application number: AU75389/91A
Authority: AU
Inventors: Glendon Bailey
Original assignee: Bailey Aluminum Products Pty Ltd
Current assignee: Hills Ltd
Priority date: 1990-05-17
Filing date: 1991-04-26
Publication date: 1993-01-14
Anticipated expiration: 2011-04-26
Also published as: AU7538991A

Description

632929 COMMONWEALTH OF AUSTRALIA The Patents Act 1952-1969 Name of Applicant: Address of Applicant: BAILEY ALUMINIUM PRODUCTS PTY. LTD.

69 ACTIVITY STREET ACACIA RIDGE QUEENSLAND 4110

AUSTRALIA

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Actual Inventor: Address for Service: GLENDON BAILEY CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, Qld. 4000, Australia.

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COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: AN IMPROVED STEPLADDER The following statement is a full description of the invention including the best method of performing it known to us:-

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i ni; II ~I l-rrr-~~r-ip-l II I n-l THIS INVENTION relates to an improved stepladder.

Stepladders typically have a front pair of stiles forming a front pair of legs, a back pair of stiles forming a back pair of legs and a ladder top or platform to which upper ends of the stiles are secured usually for pivotal movement relative thereto. The front stiles have a plurality of steps or rungs secured thereto at spaced intervals along their length. A plurality of rungs or spacing members extend between the back I pair of stiles to space the stiles apart. The stiles of each pair may be parallel to one another or converge towards each other.

When in a storage position the pairs of stiles are arranged closely adjacent one another In the use position the pairs of stiles are moved away from each other to provide an A frame configuration. Stays are present to limit the degree to which the pairs of stiles can be moved away from one se 0 another and to lend stability to the ladder during use.

The stays employed have sometimes simply been cords .99.

or chains extending between the front and back pair of stiles.

Two parallel cords or chains have previously been used as have 9 99 two diagonal crossed cords or chains.

r Such types of stays adequately limited the degree of separation possible between the pairs of stiles but did not function to inhibit accidental movement of the pairs of stiles towards one another and did not provide any additional measure of torsional stability for the ladder. Torsional stability prevents the ladder from "walking" during use.

Other types of stays have also been suggested. For 3 example Australian Patent Specification 561925 discloses two parallel rigid stay members. Each stay member is pivotally secured to one stile of a pair of stiles, typically the front pair of stiles, and has a hooked free end. In the storage position the stays are arranged to extend along the associated stiles. In he use position, the free ends of the stays are hooked over pins extending outwardly from the back pair of stiles. There is a tendency for the stays to release from their hooked position if knocked. This was a real danger because the stays were secured to external edges of the ~stiles. In addition to this, collapsing the ladder from its S. use to storage position was a two handed operation requiring both stays to be unhooked simultaneously while moving the pairs of stiles towards one another. This was difficult to achieve. By having the stays mounted externally of the stiles they were prone to damage if the ladder was caused to topple.

oct9 S These stays offered better torsional rigidity than cords or chains but did not substantially sliminate "walking".

coot Australian Patent Specification 591083 discloses another stay configuration also often used for stepladders.

Such stays consisted of two stay sections pivoted to opposed stiles and to each other intermediate the pairs of stiles. An overcentre locking of the stay sections was achieved to keep the ladder in it, use position. The stay sections, because Lhey were secured to external faces of the stiles, were prone to damage. In addition, it was a two handed operation to return the ladder to its storage position from its use position. Torsional rigidity was no better than that afforded by the stay configuration of patent specification 561925.

Australian patent specification 513136 discloses a bracing assembly for a stepladder. The assembly had two spreader members, one at each side of the ladder and each being pivotally connected at its opposite ends to stiles and support sections of the ladder. The spreader members each had two sections pivotally connected end-to-end by links to provide for over centre locking.

Two pairs of bracing members extended between laterally opposite spreader member sections forming generally X-shaped bracing arrangements. The bracing assembly provided good resistance to "walking": However, collapsing of the ladder was still a two handed operation and the bracing assembly, because the spreader sections were secured to exterior faces of the stiles and support sections they were still prone to damage.

It is an object of the present invention to provide an improved stepladder which at least minimises the disadvantages S referred to above.

According to the invention there is provided a stepladder having one pair of stiles and another pair of stiles, 2V and a brace assembly including two spaced brace sections pivotally secured to respective stiles of one said pair of stiles and extending outwardly therefrom to each present a free end and a substantially U shaped brace with a transverse brace section S extending transversely across the stepladder and two brace arms extending outwardly from the brace section and terminating at free ends which are pivotally secured relative to respective stiles of the other pair of stiles, said free ends of the brace sections being pivotally secured to said brace arms adjacent said transverse section, said brace arms and said brace sections being angled inwardly and located inwardly of the stiles, whereby, when the stepladder is in its use position said transverse brace section extends above and abuts upper edges of the two spaced brace sections at a location spaced from where the free ends of the brace sections are pivotally secured to the brace arms.

The ladder can be moved from a storage to a use position. In the storage position the pairs of stiles are closely adjacent one another. In the use position the pairs of stiles define a substantial A frame with the pairs of stiles converging towards the ladder top.

The stiles of the front pair of stiles may be parallel to one another. Alternatively, these stiles may converge toward one another at the ladder top. Similarly, the stiles of the back pair may be parallel or converge. It is preferred that both 1 pairs of stiles have the same configuration. That is, the stiles of both pairs either are all parallel or all converge.

The steps provided between the four pair of stiles may be regularly or irregularly spaced although regular spacing is preferred. A plurality of steps or rungs may extend between the 2C.. stiles of the back pair. These rungs may function simply to space the stiles apart for the desired distance or may also function as steps.

The brace sections and the brace arms, because they are angled inwardly are always well within the confines of the ladder as defined by the stiles. Thus, the sections and arms may be secured to an exterior face of the stiles and still be adequately protected from damage. Preferably however, the arms and sections are secured to an inner face of the stiles. In this way and because the arms and sections are angled inwardly the chance of 6 the user accidentally touching or contacting the arms or sections is greatly reduced.

It is preferred that the angling of the arms and sections be of a compound nature such that at least the arms or the sections have two inclined portions along their length more preferably, both the arms and the sections are angled inwardly and upwardly.

The arms and brace sections may be pivotally secured relative to one another such that the transverse section extends over or above the brace sections when the ladder is in its use position. In this way, when the ladder is in its use position and the brace assembly has been moved to an overcentre locking position the underside of the transverse member abuts the brace sections, the assembly can be moved from this position by grasping the transverse section with one hand and lifting to pivot the arms and brace sections upwardly. This configuration is preferred because the transverse section is kept in the overcentre locked position by the weight of the U shaped brace and gravity.

2 A particular preferred embodiment of the invention will now be described by way of example with reference to the drawings in which: Figure 1 is a partial perspective view of a ladder according to a preferred embodiment of the invention.

Figure 2 is a diagrammatic horizontal sectional view through the ladder of Figure 1., The ladder 10 of Figures 1 and 2 has a front pair of stiles consisting of stiles 11, 12. These stiles are substantially U shaped in transverse cross-section and each has jl;i -:b .r

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o• 7 a web 13 and two opposed flanges 14, 15. A plurality of steps 16 are swaged or otherwise secured at intervals along the stiles.

The ladder top or platform and feet are not shown.

The ladder 10 has a back pair of stiles 17, 18. These stiles also have the same U shaped configuration as stiles 11, 12. A plurality of steps 19 are secured to the back stiles 17, 18.

The brace assembly 20 has two brace sections 21, 22 pivotally secured to inner faces of stiles 17, 18 by pivot pins 23. The sections are angled or bent at 24 and 25 to ensure that the sections are spaced laterally inwardly of the stiles.

The brace assembly 20 includes a U shaped brace having a transverse section 26 and two arms 27, 28. Arms 27, 28 are angled at 29, 30 to ensure that they also are positioned inwardly of the stiles. Arms 27, 28 are pivotally coupled to inner faces of stiles 11, 12 by pivot pins 31.

The free ends of sections 21, 22 are pivotally coupled to the arms 27, 28 respectively by pins 32 at locations adjacent transverse section 26. End portions 33 are directed upwardly as shown in Figure 1 and this enables transverse section 26 to abut against sections 21, 22 in an over centre fashion to lock the brace assembly in the use position shown in Figure 1. The portions 40, 41 of the arms 27, 28 between locations 42, 43 and section 26 are directed at 8 an inclined angle relative to the remainder of the arms 27, 28.

To move the ladder of Figure 1 from the use position, where the brace assembly is locked in an overcentre position, to the storage position, the user may reach between adjacent steps 16, grasp section 26 and lift. This causes the sections 21, 22 and arms to pivot upwardly and draw the pairs of stiles together. This one handed operation enables the user to steady the ladder with his free hand or to assist the movement of the front pair of stiles towards the back pair of stiles. Such assistance was not possible with prior ladders since both arms were required to move the brace members or stays from the position they assumed in the use position.

The inward cranking of the brace assembly reduces the incidence of damage or accidental movement of the brace assembly from its use position. This is further achieved by o having the sections 21, 22 and arms 27, 28 secured to inner faces of the stiles.

Claims

1. A stepladder having one pair of stiles and another pair of stiles, and a brace assembly including two spaced brace sections pivotally secured to respective stiles of one said pair of stiles and extending outwardly therefrom to each present a free end and a substantially U shaped brace with a transverse brace section extending transversely across the stepladder and two brace arms extending outwardly from the brace section and terminating at free ends which are pivotally secured relative to respective stiles of the other pair of stiles, said free ends of the brace sections being pivotally secured to said brace arms adjacent said transverse section, said brace arms and said brace sections being angled inwardly and located inwardly of the stiles, whereby, when the stepladder is in its use position said ig." transverse brace section extends above and abuts upper edges of the two spaced brace sections at a location spaced from where the S: free ends of the brace sections are pivotally secured to the brace arms.

2. The stepladder of Claim 1 wherein l.ie brace sections a have their free ends pivotally secured to respective said stiles S forming a front pair of stiles of the stepladder and the free ends of the brace armed are pivotally secured to respective said stiles forming a back pair of stiles.

3. 'he stepladder of Claim 1 or 2 wherein the stiles of each said pair of stiles are parallel to one another.

4. The stepladder of Claim 1 or 2 wherein the stiles of each said pair of stiles converge toward one another at a ladder platform.

The stepladder of any one of Claims 1 to 4 including I34 -SdI Y'1 a plurality of steps secured to said one pair and at regular intervals therealong.

6. The stepladder of any one of Claims 1 to 4 including plurality of rungs secured to the other pair of stiles and at regular intervals therealong.

7. The stepladder of any one of the preceding claims wherein the brace sections and said brace arms are secured to exterior faces of the stiles.

8. The stepladder of any one of Claims 1 to 6 wherein the brace sections and said brace arms are secured to interior faces of the stiles.

9. The stepladder of any one of Claims 1 to 8 wherein the arms and the brace sections each have a first portion angled inwardly of transverse sides of the stepladder and a second portion angled upwardly relative to the first portion. The stepladder of any one of Claims 1 to 9 wherein, when the ladder is in its use position the transverse section extends over the brace section and provides for an overcentre locking of the brace assembly. a. 11. A stepladder substantially as herein described with reference to the accompanying drawings. DATED this 21 day of October, 1992. BAILEY ALUMINIUM PRODUCTS PTY LTD By their Patent Attorneys CULLEN CO. r T