AU2007101150A4

AU2007101150A4 - Step ladder/scaffold platform assembly

Info

Publication number: AU2007101150A4
Application number: AU2007101150A
Authority: AU
Inventors: Carl Behn; Ronald Thomas Delaforce
Original assignee: Hills Ltd
Current assignee: WERNER INTERNATIONAL POC GmbH
Priority date: 2007-12-03
Filing date: 2007-12-03
Publication date: 2008-01-10
Anticipated expiration: 2015-12-03
Also published as: AU2007101150B4

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT

ORIGINAL

Name of Applicant: Actual Inventors: Agent and Address for Service: Invention Title: Hills Industries Limited Ronald Thomas DELAFORCE Carl BEHN MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia STEP LADDER/SCAFFOLD PLATFORM ASSEMBLY The following statement is a full description of this invention, including the best method of performing it known to us.

This invention relates to platforms used on step ladders.

BACKGROUND

Ladders in particular step ladders are light weight so they can be carried and S 5 lifted for use, transportation, and storage as are certain types of scaffold. The preference is that they be moved or carried easily by one person.

Light weight but sufficiently strong material used to construct the frame of a ladder/scaffold ranges from timber to steel of various grades and sizes dependent on the recommended use and loading of the ladder. Aluminium is also used.

The tread/s and platform/s of a ladder are also constructed using the same range of materials, typically the same material used for the frame of the ladder, but alternative material for the treads includes plastic which when used can reduce the total weight of the ladder compared to a ladder made of the same material. In some cases the use of easily moulded step material (such as plastics) can also reduce the cost of that component and hence the finished ladder, and in an increasingly competitive market place cost reductions are important regardless of sometimes very small differences on component costs.

However, the reduced cost of one or more components of different materials can be off-set if the complexity of additional construction steps are taken into account. Furthermore, there is a need to ensure that the two or more materials used are designed to fit together and stay fitted during the life of the product, especially if the structural integrity of the fit is important to the structural integrity of the product.

Clearly, the type and quality of the materials used to construct a ladder and scaffold can be important to the long term integrity of the ladder/scaffold and careful choice in accordance with product reputation and applicable standards is required.

SIt is therefore innovative to provide one or more components that are designed to fit together in one or more ways that simplifies the steps of construction and at the same time provides long term structural integrity 0 especially in the construction of an article such as a ladder or scaffold using suitable materials for the one or more components or assembly of components. It is also innovative to create a design that can use one or more components of different materials to provide one or more of the abovementioned characteristics.

BRIEF DESCRIPTION OF THE INVENTION In an aspect of the invention a step ladder/platform assembly for fitment to a ladder/platform includes a platform base having a plurality of strengthening member retaining portions, a plurality of platform strengthening members, one for each of the retaining portions in the said platform base and retained by the platform base, each said platform strengthening member having an engagement portion for a further platform strengthening member, and a further platform strengthening member located in the engagement portion of each of the plurality of platform strengthening members and associated with the platform base.

In a further aspect of the invention a step ladder/platform assembly wherein the further platform strengthening member has a shape which is slidable into the engagement portion of the plurality of platform strengthening members.

In a further aspect of the invention a step ladder/platform assembly wherein 0 Othe plurality of strengthening member retaining portions in the platform base U are channels.

C 5 In a further aspect of the invention a step ladder/platform assembly wherein the platform base is plastic and the platform strengthening members are not 0 plastic.

In a yet further aspect of the invention a method of construction of a step ladder/platform assembly having a platform base with a plurality of strengthening member retaining portions, the method includes the steps of: a) placement of the plurality of platform strengthening members, one for each of the retaining portions in the said platform base to be retained thereby to the platform base, each said platform strengthening member having an engagement portion for a further platform strengthening member, and b) placement of the further platform strengthening member in the engagement portion of each of the plurality of platform strengthening members and associated with the platform base.

Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims.

It should be noted that there are many alternative ways of implementing both the process and apparatus of the present invention. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Throughout this specification and the claims that follow unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a Sstated integer or group of integers but not the exclusion of any other integer O or group of integers.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art Sforms part of the common general knowledge.

0Specific embodiments of the invention will now be described in some further detail with reference to and as illustrated in the accompanying figures. These embodiments are illustrative, and not meant to be restrictive of the scope of the invention.

BRIEF DESCRIPTION OF THE FIGURES Fig. 1 depicts a perspective view of a step ladder in a use position; Fig. 2 depicts a side view of the step ladder of Fig. 1; Fig. 3 depicts a side view of the step ladder of Fig. 2 in a folded position; Fig. 4 depicts a perspective view of the step ladder of Fig. 3; Fig. 5 depicts top view of a step ladder platform assembly; Fig. 6 depicts a front view of a step ladder platform assembly of Fig. Fig. 7 depicts a side perspective view of the step ladder platform assembly of Fig. Fig. 8 depicts a right hand side view of a step ladder platform assembly of Fig.

Fig. 9 depicts a perspective view of assembled platform strengthening members; and Fig. 10 depicts a bottom perspective view of an assembled step ladder platform assembly.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION Figures 1 to 4 depict four different views of a step ladder of a type that may use the platform described herein. Alternatively, but not depicted are platform assemblies that may use the platform described herein. The illustrated step ladder includes a frame 10 having pairs of side rails 12, 14 and 16 and 18 with both pairs joined 20 and 22 at one end. The join allows at least one of the side rails to rotate with respect to the other to allow the rails of a pair to be located adjacent each other and separated a distance limited by the engagement of an element between the rails. In this embodiment, the separation is limited by the platform 24 and arms 26 and 28 (arm 28 is not shown) both of which pivot to allow the platform to fold down from a raised position to the substantially horizontal position illustrated.

The step ladder frame 10 is in a usable condition when the pairs of side rails are separated and the platform 24 is in a horizontal position. The step ladder frame 10 is intended for storage or relocation when the pairs of side rails are brought together and the platform 24 is brought into alignment with the pairs of rails.

The hand rail 30, in this embodiment, also folds down to a storage position as depicted in figures 3 and 4.

The platform 24, when located in a horizontal use position, provides an area of sufficient size to allow a user to step upon the platform with both feet, providing a stable surface for the user. If that person is required to shift position on the platform, the size of the platform accommodates that 0 Orequirement better than if the ladder only had treads.

The platform 24 depicted in figure 4 has no strengthening members of any kind as is illustrated by the underside view of the platform 10 in figure 4 but this is done for illustrative purposes only.

Figure 5 depicts a top view of the platform assembly 52 of the invention (the platform having the same top surface pattern and substantially same shape as the platform 24 depicted in figures 1 to 4, and for the purposes of description hereafter is designated platform 54).

The platform assembly type described and illustrated is useable with a number of different types of ladders as well as with scaffold arrangements such as light duty scaffolds. Indeed any time there is a desire or need to provide an area for the placement of the feet of a user or for equipment during use of the ladder/scaffold apparatus the platform assembly described herein is useable when attached to the ladder/scaffold.

Figure 6 depicts a front view of the platform assembly 54 shown in Fig. showing in particular the top surface 60 of the platform and a view of the raised kick plate 62 at the rear of the platform assembly. The kick plate is a useful safety feature as the user is able to feel the rear limit of the platform with their feet without having to see it. Also shown are top hat extrusions 64 and 66 that are used to affix the platform to opposed rails of the frame of the step ladder. A perspective view of those extrusions is shown in Fig. 7 and a side view of one of those extrusions is shown in Fig. 8.

Figure 7 depicts a side perspective view of the platform assembly of Fig. Figure 8 depicts a right hand side view of the platform assembly 52 of Fig.

O

OThe extrusion 64 (Figs. 7 and 8) is depicted as having four apertures sized to U accommodate fixing elements, such as for example screws when the plates are Sfitted to rails of the step ladder frame although more or fewer screws and S 5 fixings can be used. The circular end of a strengthening member is shown on the outer facing surface of the extrusion 64 in both Figs. 7 and 8. The circular shape results from the swaging technique used to fix the further strengthening member to the extrusion and also to the cylindrical shape of the further strengthening member used in the illustrated embodiment. The dimensions and or relative spacing of the elements are an example only of the size and location of the elements described. The arrangement described is an example of a way to secure the platform to another structure. The particular arrangement described allows the platform to rotate relative to the structure, other securing arrangements may not provide such a feature.

Figure 9 depicts a perspective view of assembled platform strengthening members. The three strengthening members 92, 94 and 96 and a further strengthening member 98 are shown in assembled form apart and separate from the platform base 54 shown in Figs 5, 6, 7, 8 and 10, for clarity only.

In this embodiment the ends of each of the three strengthening members have an aperture which is sized to accommodate the passing through of the further strengthening member 98. So as to allow the three strengthening members to rotate with respect to the further strengthening member, the aperture in each member is circular to accommodate a cylindrically shaped further strengthening member, but any suitable shape would suffice if other elements such as grommets or other rotation permitting elements were provided. The accommodations made allow the further strengthening member to engage the other strengthening member such that they are not readily separated in use.

Alternative arrangements to provide such an engagement are possible and well within the skill of one skilled in the art once the requirement is

O

Oidentified.

The material from which any of the strengthening members are made is in the embodiment, aluminium, but could be of plastic or other suitable material.

Aluminium is chosen because it is light and strong for prolonged periods of 0 time (almost regardless of the environment) and relatively cheap.

Also shown in Fig. 9 is a pivoting support arm 100 which pivots about fixing 102, which in this embodiment is a nut and bolt that are placed through holes at opposite sides of the member 94 and an aperture (not shown) at an end of the support arm 100. The support arm 100 is sized to fit within an aperture in the member 94 or if the member is shaped, the arm fits into the space between the sides of the member. The free end of the support arm is located and fixed onto the frame of the step ladder and when fixed thereto allows the platform strengthening member 94 to be further supported by the frame, in the in use position and to maintain the platform in a substantially horizontal position or in a fixed and stable position relative to the platform when the step ladder is not located on a surface level or otherwise.

Figure 10 depicts an underside perspective view of an assembled platform assembly 52 showing the platform strengthening members 92, 94, 96 and 98 in place in the platform base 54.

The way in which the platform assembly is constructed is described by way of example for the embodiment depicted herein but there are many other modes of construction which will be apparent to those skilled in the art once they understand the principles of the innovation disclosed in this specification.

The platform assembly 52 of this embodiment includes a platform base 54 made of plastic. The type of plastic is chosen by a person skilled in the art so as to retain its shape and structural strength for at least the anticipated

O

Olifetime of the step ladder. The shape of the underside of the platform can Stake many forms, but the example depicted in Fig. 10 shows a cellular form including a plurality of ribs and walls to give strength to the moulded plastic form of the platform, which is the surface that supports the user and any equipment they may have with them.

The design of the shape of the underside of the platform also includes three channels (not explicitly shown) that run from the front 104 to the rear 106 of the underside of the platform 54 integral to the form of the underside of the platform. The channels are sized to accommodate three strengthening members of complimentary shape, at least in respect to the facing shape of the members. The channels may be arranged to not retain the strengthening members from falling out of them, so there may be other forms of retention to suit that purpose if required. The channels thereby retain the members in position from at least sideways and longitudinal movement and are referred to herein as retaining portions of the platform because they retain the strengthening members with respect to at least side ways movement.

The retaining portion however may be provided in alternative forms, such as for example tangs or clips which stand proud of the underside of the platform 54 or many other forms that retain the strengthening members to the platform during the lifetime of the step ladder.

In this embodiment the strengthening members 92, 94 and 96 are accommodated in the retaining portions by interference fit. The strengthening members 92, 94 and 96 are made of aluminium and in this embodiment have a shape which is sized to interference fit into the channels, with the opening of the shape facing away from the underside of the platform 54 as is best illustrated in Fig. 10 and shown in end view in Fig. 9. This is only specifically required for the centrally located member 94 since it has an added element including a pivotable support arm 100 which pivots about fixing 102 Sas shown in Fig 9 and is conveniently fitted in the manner described U previously.

CI

The channels in the platform base 54 of this embodiment can also be adapted to retain the members in other ways, such as for example by the provision of I tabs or tangs (not shown) on the lower and outer sides of the channels and in this embodiment suggested to be on the lower edge of the channel. The tabs or tangs are resiliently moveable so that a strengthening member can be pressed past the tab when fitting the member to the platform but then the tab is biased to spring back to prevent the member readily exiting the channel.

The simplest form of tab is formed during the platform moulding process by way of a deformation of the plastic along the channel edge and letting the plastic material of the base provide the resiliency required to facilitate initial fitment and final retention positions.

The use of such tabs or tangs is but one of many ways in which the platform base and the channels in particular can be provided means to retain the strengthening member to the platform.

The methods and means described above provide for the partial construction of the platform assembly to be substantially achieved without the need for fixings such as rivets or bolts and nuts in the process of fitting the strengthening member.

The underside of the platform 54 also has a further channel running from one side 108 to the other side 110 adjacent the front 104 of the platform. This channel is sized to accommodate a further platform strengthening member, which in this embodiment is the member 98 shown in Fig 9 as well as the ends of the other platform strengthening members 92, 94 and 96 which pivotably connect to the further platform strengthening member 98. The further channel in the platform 54 is not necessarily a retaining portion of the platform but 0 Othere may be means for providing a retaining function such as for example atangs or clips formed out of plastic or if economical, in terms of time and Smoney, from other materials fixable to the platform.

In one embodiment of the construction of the platform assembly, each of the strengthening members 92, 94 and 96 are placed in and retained by the platform 54 in a respective retaining portion and then the further platform strengthening member 98 is located in the further channel in the platform 54 by sliding it through an aperture in the side of the platform and also through the apertures in the ends of each of the platform strengthening members 92, 94 and 96. The use of a cylindrical rod or tube preferably of aluminium material for the platform strengthening member assists the passage of the member into place. The use of a cylindrical rod is but one example as is the particular method of construction described.

The ends of the member 98 can then be terminated to retain the various parts together. In the embodiment shown in Figs 6, 7 and 8, a termination can be achieved by using, on each end of the member 98, a top hat extrusion (64 and 66) which is swaged to the end of the member. The extrusions can then be used to affix the step ladder platform assembly to opposed rails of the frame of the step ladder as described previously.

The termination of the ends of the further strengthening member may become integral to the fitment of the platform assembly to a ladder or other structure, the main aim being the association of the further strengthening member to the platform assembly.

There can be variations to the method of construction for this particular embodiment, one of which includes assembling the platform strengthening members before fitment to the underside of the platform and then swaging Sthe ends of the member 98 to the top hat extrusions.

("4 It will be appreciated by those skilled in the art that the invention is not S 5 restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

("4

Claims

1. A step ladder/scaffold platform assembly for fitment to a ladder/platform arrangement including a platform base having a plurality of strengthening member retaining portions, Sa plurality of platform strengthening members, one for each of the retaining portions in the said platform base and retained by the platform base, each said platform strengthening member having an engagement portion for a further platform strengthening member, and a further platform strengthening member located in the engagement portion of each of the plurality of platform strengthening members and associated with the platform base.

2. A step ladder/scaffold platform assembly according to claim 1 wherein the further platform strengthening member has a shape which is slidable into the engagement portion of the plurality of platform strengthening members.

3. A step ladder/scaffold platform assembly according to claim 1 wherein the plurality of strengthening member retaining portions in the platform base are rotatable with respect to the further platform strengthening member.

4. A step ladder/scaffold platform assembly according to claim 1 wherein the platform base is made of plastic and the platform strengthening members are made of metal. A method of construction of a step ladder/scaffold platform assembly having a platform base with a plurality of strengthening member retaining portions, the method including the steps of: a) placement of the plurality of platform strengthening Smembers, one for each of the retaining portions in the said platform base to be oretained thereby to the platform base, each said platform strengthening member having an engagement portion for a further platform strengthening Cc, member, and b) placement of the further platform strengthening member in n the engagement portion of each of the plurality of platform strengthening members and associated with the platform base.