WO2008041156A2

WO2008041156A2 - A-framed step ladder with slidably displaceable extension member

Info

Publication number: WO2008041156A2
Application number: PCT/IB2007/053901
Authority: WO
Inventors: Harold Bremner Sharp
Original assignee: Harold Bremner Sharp
Priority date: 2006-10-06
Filing date: 2007-09-26
Publication date: 2008-04-10
Also published as: WO2008041156A3

Abstract

The invention relates to an A-frame step ladder which includes two hingedly connected frame-like members (12, 14) that have collapsible stay members (16) acting between them that determine the A-frame configuration of the step ladder. Each frame-like member includes a pair of stiles (14, 18) and cross members (20) holding the stiles in a required spaced configuration, the cross members of one of the frame-like members forming the rungs of the ladder. The frame-like member including the rungs of the ladder includes two elongate, substantially parallel, spaced apart guide formations (28) that extend along the length of the respective stiles and within which arms (34) of an extension member (30) are slidably displaceable. The arms carry a support formation (32) that is locatable in different positions above the top rung of the ladder by the displacement of the arms in the guide formations. Locating means releasably locates the support formation in its different positions.

Description

A LADDER

THIS INVENTION relates to a ladder.

The invention relates particularly to a ladder of the type that is commonly known as an A-frame step ladder and that includes two hingedly connected frame-like members that each includes a pair of spaced apart stiles and cross members holding the stiles in their required spaced configuration, the cross members of one of the frame-like members forming the rungs of the step ladder. The two hingedly connected frame-like members have collapsible stay members acting between them that determine the pivotally displaced configuration of the frame-like members in the operative erect configuration of the step ladder, while permitting collapse of the frame-like members onto one another into the inoperative storage configuration of the step ladder. It will thus be understood that in the operative erect configuration of the step ladder, the two frame-like members are pivotally displaced to form, together with the stay members, an A-configu ration when viewing the step ladder in side view, hence an A-frame step ladder. In this configuration the step ladder can be supported in a stable configuration on a support surface, permitting a person to climb up the ladder via the rungs associated with the said one of the frame-like members.

Any reference hereinafter to an A-frame step ladder must be interpreted as a reference to a ladder that incorporates at least the components and parts of the step ladder as above defined. According to the invention there is provided an A-frame step ladder, which includes

two hingedly connected frame-like members having collapsible stay members acting between them for defining the operative A-frame configuration of the step ladder, one of the frame-like members including a pair of spaced apart stiles, cross members forming the rungs of the step ladder secured between the stiles and two elongate, substantially parallel, spaced apart guide formations extending substantially along the length of the respective stiles;

an extension member including a support formation and two substantially parallel, spaced apart support arms extending from the support formation, the support arms being slidably received within the respective guide formations to be slidably displaceable between an inoperative position of the extension member, in which the support arms are effectively retracted within the guide formations and the position of the support formation coincides substantially with the top end of the frame-like members, and at least one operative position of the extension member, in which the support arms are slidably displaced within the guide formations into a position in which they extend from the guide formations and the support formation is supported at an elevated level above the top end of the frame-like members; and

locating means for releasably locating the extension member in an operative position.

According to one particular embodiment of a step ladder, in accordance with the invention, the stiles of at least the frame-like member carrying the cross members forming the rungs of the step ladder are downwardly splayed and the guide formations are secured to the frame-like member adjacent its respective stiles in a substantially parallel, spaced apart configuration with respect to one another. According to a second particular embodiment of a step ladder, in accordance with the invention, the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder define segments that are disposed substantially parallel to one another and the guide formations are carried by the stiles in the region of the substantially parallel segments thereof.

According to a third particular embodiment of a step ladder, in accordance with the invention, the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder define segments that are disposed substantially parallel to one another and the stiles themselves serve as the guide formations in the region of these segments.

Particularly for the above second and third particular embodiments of the step ladder of the invention, the operative bottom end segments of the respective stiles of the frame- like member carrying the cross members forming the rungs of the step ladder are downwardly splayed, forming feet for this frame-like member that are spaced apart further than the spacing between the substantially parallel segments of the stiles. Also for these embodiments of the step ladder, the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder may comprise elongate extruded sections.

For all the above embodiments of the step ladder of the invention, the guide formations may be in the form of one of channel sections and rectangular box sections, which also may be extruded sections. Generally, the configuration of the cross members forming the rungs of the step ladder and their mode of location with respect to the stiles are suitably configured to accommodate the required sliding displacement of the support arms of the extension member with respect to the guide formations.

Further according to the invention, the locating means of the step ladder may include, pivotally mounted on at least one of the support arms of the extension member, a spring biased catch formation which, in a predetermined operative position of the extension member in which the support formation is elevated above the top end of the frame-like members, is biased into a position in which it engages a formation defined by the guide formation in which the support arm is slidably displaceable, for preventing displacement of the support arm towards its inoperative position. The spring biased catch formation particularly may serve to locate the support formation of the extension member in different predetermined operative positions. The catch formation particularly is physically displaceable against its bias to release it from its engagement with a formation defined by the guide formation, to permit displacement of the extension member towards its inoperative position.

The locating means of the step ladder of the invention preferably includes a spring biased catch formation pivotally mounted on each of the support arms of the extension member.

For locating means as above envisaged, each support arm of the extension member on which a spring biased catch formation is pivotally mounted is one of an elongate rectangular box section and a channel section within which an aperture is defined that, upon displacement of the extension member into a predetermined operative position, is positioned in register with an aperture defined in the guide formation to thereby provide for the catch formation to be biased into a position in which it engages the guide formation via the aperture, to hold the extension member in the operative position.

Still further, each spring biased catch formation of the locating means may have a displacement means operatively linked therewith in a configuration in which it is externally accessible on the ladder for displacing the catch formation into a release position, in which the extension member can be displaced towards its inoperative position. The displacement means may comprise a cable element connected to the catch formation and a lever that is externally mounted on the ladder in a configuration in which it can act on the cable for displacing the catch formation connected thereto into a release position.

Further according to the invention, the A-frame step ladder may include trap means for trapping at least one of the support arms of the extension member within its guide formation in a configuration in which the support arm cannot be pulled from its guide formation. The trap means may comprise a spring biased catch formation pivotally mounted on a support arm in a configuration in which it is operable to engage a formation defined by the guide formation in which it is displaceable and that is positioned in a location in which the extension member is prevented from further displacement from its inoperative position. The trap means also may be associated with release means that is operable to render the trap means ineffective, thereby to permit the extension member to be separated from the remainder of the ladder by its support arms being pulled from their respective guide formations.

The step ladder of the invention may include locking means for locking the extension member in its inoperative position when the frame-like members of the ladder are collapsed, the locking means comprising a spring biased locking pin located on a stile adjacent a guide formation carrying a support arm of the extension member. More particularly, with the extension member positioned in its inoperative position and upon collapse of the frame-like members, the frame-like member not carrying rungs will act on the locking pin for its engagement with registering holes in the guide formation and the support arm, slidably displaceable therein, for holding the extension member in its inoperative position.

Still further, the step ladder may include a holding arrangement for releasably holding the frame-like members in their collapsed configuration. Also, the step ladder may include a foot platform that is displaceably locatable between the rung operatively beneath the top rung of the frame-like member carrying the rungs of the step ladder and the other frame-like member and that forms an extension of the said rung when so located. The foot platform particularly is pivotally mounted on the said other frame-like member to be pivotally displaceable between an inoperative configuration, in which it is folded into the general plane of the frame-like member on which it is mounted, and an operative configuration, in which it cooperates with a support formation on the frame-like member carrying the rungs, for supporting the platform in its configuration in which it forms an extension of the said rung. A holding arrangement further is provided for releasably holding the foot platform in its inoperative configuration.

The above and further features of the step ladder of the invention are described hereinafter with reference to examples of the step ladder of the invention that are illustrated in the accompanying diagrammatic drawings. In the drawings:

Figure 1 shows a three-dimensional view of a first embodiment of a step ladder, in accordance with the invention;

Figure 2 shows a front view of a the step ladder of Figure 1 ;

Figure 3 shows a front view of the extension member of the step ladder of

Figure 1 ;

Figure 4 shows a front view of a second embodiment of a step ladder, in accordance with the invention;

Figure 5 shows a front view of a third embodiment of a step ladder, in accordance with the invention;

Figure 6 illustrates in side view the operation of a locating means forming a part of a step ladder, in accordance with the invention; Figures 7 to 9 illustrate in different views the operation and configuration of the locating means as shown in Figure 6;

Figures 10 to 12 illustrate in side view the configuration and operation of a locking means that can form a part of a step ladder, in accordance with the invention;

Figures 13 and 14 illustrate in different views the operation and configuration of means to trap the support arms of the extension member of a step ladder, in accordance with the invention, within their guide formations; and

Figures 15 and 16 illustrate respectively in side view and sectional top view a clipping arrangement for holding the frame-like members of a step ladder, in accordance with the invention, in a collapsed configuration.

Referring initially to Figures 1 and 2 of the drawings, a first embodiment of a step ladder, in accordance with the invention, is designated generally by the reference numeral 10. The step ladder 10 includes two hingedly connected frame-like members, 12 and 14 respectively, the members 12 and 14 having collapsible stay members 16 acting between them in a conventional configuration for determining the operative erect configuration of the step ladder 10, while permitting collapse of the frame-like members onto one another into the inoperative storage configuration of the step ladder. Insofar as the construction of the step ladder in the above regard is conventional, this is not described further herein.

The frame-like member 12 of the step ladder 10 includes a pair of spaced apart stiles 18 in the form of elongate channel sections, the stiles 18 having the rungs 20 of the step ladder secured between them as shown. As is clear from the drawings, the stiles 12 are disposed substantially parallel with one another, except for the operative bottom segments 22 thereof that are downwardly splayed, clearly to enhance the stability of the step ladder when supported in its operative configuration on a support surface. As is clearly illustrated, the frame-like member 14 also includes a pair of stiles 24, the stiles 24 being downwardly splayed and being held in their spaced configuration by the cross member 26 and the top rung 20.2, as is conventional.

The stiles 18 of the frame-like member 12 each have a guide formation 28 in the form of an elongate rectangular box section secured thereto along the length thereof, the rungs 20 of the ladder 10 being suitably cut-away as shown to accommodate these guide formations.

The step ladder 10 includes also an extension member (see also Figure 3), designated generally by the reference numeral 30, the extension member including a tray-like support formation 32 that has two support arms 34 extending therefrom in a parallel spaced configuration. The support arms 34 also comprise rectangular box sections, particularly dimensioned to be slidably received within the respective guide formations 28.

It will thus be understood that the extension member 32 is displaceable between an inoperative position, in which the support formation 32 effectively lies on the top rung 20.2, and a plurality of operative positions (as explained hereafter), in which the support formation is elevated above the top end of the frame-like members, particularly for purposes hereinafter described.

The step ladder 10 includes also locating means as described hereafter with reference to Figures 6 to 9 of the drawings, which serve to locate the extension member 30 in its different operative positions, and means for trapping the support arms 34 within the guide formations 28, thus to ensure that the extension member cannot be separated from the guide formations by pulling the support arms from the guide formations.

The step ladder 10 includes still further a foot platform 36 that is pivotally mounted on the frame-like member 14, being displaceable between an inoperative configuration, in which it is pivotally displaced into the general plane of the frame-like member 14, and an operative configuration, in which it cooperates with support formations (not shown in Figure 1 ) that are located on the frame-like member 12 for supporting the platform in the configuration as shown, thus permitting a person to stand on the rung 20.1 of the ladder 10 with his feet also partially supported on the platform. The configuration of the foot platform is described in more detail hereafter with reference to Figure 10 of the drawings.

As is clearly apparent from Figure 1 of the drawings, by providing a step ladder having an extension member as described, a person can safely use the step ladder, even when standing on the operative top rung 20.2 thereof, the extension member clearly being positionable into an operative position in which the person can hold onto the extension member for additional stability. Still further, the support formation 32 is configured to provide for the support of tools, and the like, thereon, which facilitates performing different functions at an elevated level above the ground while using the ladder.

Referring to Figure 3 of the drawings, the extension member 30 of the step ladder 10 is separately shown, the member including the support formation 32 and support arms 34 as described. Near the operative bottom end of the support arms 34, the box section forming each support arm has a pair of slot-like apertures, 38 and 40 respectively, formed therein, these apertures being disposed and configured to cooperate with the locating means and the means to trap the support arms within the guide formations, which are referred to above and are described in more detail hereafter.

It will be understood that the general principles of the step ladder 10 as described, particularly in relation to the extension member thereof, can be applied to many different configuration step ladders in equivalent manners, Figures 4 and 5 illustrating two different embodiment step ladders that include an extension member as envisaged. These step ladders are briefly described hereafter with the corresponding parts thereof designated by the same reference numerals used in conjunction with the step ladder 10 as shown in Figure 1.

Referring to Figure 4 of the drawings, the step ladder shown therein is designated generally by the reference numeral 50 and, in this case, the stiles of both the frame-like members, 12 and 14, are splayed downwardly from the top end of the frame-like members, as is well known in conjunction with most known step ladders of the type. In this case, the guide formations 28 are secured to the stiles 18 of the frame-like member

12 in a configuration in which they extend in a parallel spaced configuration as shown, thus to accommodate an extension member (not shown) in the configuration as shown in

Figure 2 of the drawings.

Referring to Figure 5 of the drawings, the step ladder shown therein is designated generally by the numeral 60, the general construction thereof in terms of its frame-like members, 12 and 14, being essentially the equivalent of the step ladder 10 as shown in Figure 1. In this case, the stiles 18 of the frame-like member 12 and guide formations 28 are formed integrally with one another as an extrusion, this extrusion, as illustrated in cross-sectional detail, defining a channel section 62 and a rectangular box section 64. The opposite channel sections therefor have the rungs 20 of the ladder secured between them, while the guide formations 28 are externally disposed as shown, with the support arms 34 of the extension member 30 thereof being slidably received therein. Clearly, the stiles 18 and guide formations 28 can be similarly configured by being separately formed and secured together.

Referring now to Figure 6 of the drawings, the configuration and operation of locating means for locating the extension member 30 of any one of the step ladders 10, 50, 60, is illustrated. Again, with equivalent parts being designated by the same reference numerals as before, there is shown a stile 18 of a frame-like member 12, the stile 18 having a guide formation 28 in the form of a rectangular box section secured thereto along the length thereof. The extension member 30 again includes a support platform 32 and two support arms 34 (only one shown) extending therefrom, the support arm shown being slidably located within the guide formation 28.

Near the operative bottom end of the support arm 34, a catch formation 70 is pivotally secured thereto, being pivotally displaceable about a pivot axis 72. A spring 74 acts on an arm 76 of the catch formation 70 for urging an end segment 78 of the catch formation 70 into the position illustrated, which is a position in which it projects through registering slot-like apertures defined in adjacent walls of the support arm 34 and the guide formation 28. The apertures defined in the support arm 34 are illustrated in Figure 3 of the drawings, in which they are designated by the numeral 38, while the apertures in the guide formations are illustrated in Figures 4 and 5 of the drawings, in which they are designated by the reference numerals 80. As is clear from Figures 4 and 5 of the drawings, the apertures 80 in the guide formations 28 are operatively associated with the levels of the rungs 20 of the associated step ladder, thus providing for different elevated levels of the support formation 32 of the extension member 30 that are operatively linked with the levels of the rungs. It is envisaged, therefore, that the support formation 32 of the extension member 30 of the step ladder of the invention can be positioned at a convenient level for each particular rung of the ladder on which a person may stand.

As is clearly apparent from Figure 6 of the drawings, by displacing the support formation 32 of the extension member from a lower to a higher position, the extension member can merely be pulled or pushed upwardly, resulting in pivotal displacement of the catch formation 70 into a position in which it is effectively contained within the support arm only, the profile of the catch formation being configured to accommodate this. When the extension member reaches a predetermined higher level, the biasing force on the catch formation 70 will serve to displace the catch formation back into its operative configuration, in which reverse displacement of the extension member is again prevented. A rotating wheel 82 mounted on the catch formation 70 is positioned to run against the inner wall of the guide formation 28 during such displacement, and also during opposite displacement as described hereafter, thus to reduce frictional forces within the guide formation and facilitating the displacement of the extension member.

The arm 76 of the catch formation 70 further has one end of an elongate cable 84 secured thereto in the position shown, the opposite end of the cable being secured to an operating lever 86 which is pivotally mounted on the extension arms 34 (see also

Figures 1 and 3), being displaceable from the position as shown in Figure 6 to a position in which, by acting on the support arm 76, the catch formation 70 is displaced out of engagement with the guide formation 28, thus to permit operative downward displacement of the extension member.

It will be appreciated in the above regard that both the support arms of the extension member will be associated with a locating means as described, as is clearly apparent from the drawings.

Figures 7 to 9 illustrate the configuration of the locating means as described with reference to Figure 6 in additional detail, but insofar as the exact construction of the locating means and mode of operation is variable and insofar as the embodiment described is clearly illustrated, this is not described in further detail herein. However, and as shown in these figures and also in Figures 13 and 14 of the drawings, a second catch formation 90 is located in at least one of the support arms 34, the catch formation 90 effectively being oppositely directed to the catch formation 70 and having a spring 92 acting thereon for urging it into its operative configuration. This catch formation 90 serves to trap the support arm on which it is mounted within its guide formation, the catch formation 90 being displaced into its operative configuration immediately before the support arm 34 can exit from the guide formation 28 in which it is slidably displaceable. In this position of the support arm 34, registering slot-like apertures in the adjacent walls of the support arm 34 and guide formation 28 provide for the catch formation 90 to project therethrough into a position in which further upward displacement of the support arm will not be permitted (see Figure 13). This still further enhances the safety associated with the use of the extension member on a ladder as proposed. In practice, the catch formation 90 is rendered accessible for physically displacing it into its inoperative configuration, if it is indeed required to pull the extension member from the frame-like member of its associated ladder.

Alternatively, in order to permit the extension member to be pulled from the frame-like member of its associated ladder, a blocking formation 1 10 may be pivotally mounted on a stile of its frame-like member in a configuration in which it is pivotally displaceable between its position as shown in solid lines in Figure 13 and a position as illustrated in Figure 14, in which it blocks registering apertures 1 12, thus permitting the catch formation 90 to bypass these apertures and thereby permit the extension member to be pulled from the guide formations. The displacement of the formation 1 10 can be conveniently performed with the aid of a screwdriver acting on the pivot 1 14, as is clearly apparent from the drawings.

Referring now to Figures 10 to 12 of the drawings, the foot platform 36 is illustrated in Figure 10, both in its operative position (in solid lines) in which its free end is supported on support formations 92 provided on the respective stiles of the first frame-like member 12, and in a storage position (in dotted lines) in which a clip 94 is engaged with a complementary engagement formation (not clearly shown) provided on one of the stiles 24 of the frame-like member 14, for holding it in this position. In its operative position, the platform enhances the stable positioning of a person on the ladder, the rung 20.1 together with the platform clearly being the preferred highest rung of the ladder that should ordinarily be used, although the rung 20.2 also can be used. A magnet arrangement, instead of the clip 94 and the complementary engagement formation with which it operatively cooperates, also can be used for holding the platform in its storage position.

The step ladder 10 includes also a locking means in the form of a locking pin 100 that is displaceably mounted on a stile 18 of the frame-like member 12 of the associated step ladder, the pin being biased by a spring 102 into its position as shown in Figure 1 1. Upon storage of the ladder and with the extension member fully retracted, upon hingedly displacing the frame-like members 12 and 14 towards one another, the frame-like member 14 will act on the pin 100 for displacing it into its position as shown in Figure 12, in which it projects through registering apertures 104 in adjacent walls of the guide formation 28 and support arm 34, for holding the extension member in this retracted position. Clearly, the locking mechanism may be similarly operable for holding the extension member in any other position when the step ladder is collapsed as shown in Figure 12 of the drawings. When the frame-like members are again displaced into their operative position, the pin will be biased into its position as shown in Figure 1 1 , thus permitting displacement of the extension member into an operative position.

Referring to Figures 15 and 16 of the drawings, in order to prevent displacement of the frame-like members into their operative configuration when this is not intended and thus to prevent the extension member from being displaced from its fully retracted position, complementary clipping formations, 120 and 122 respectively, are secured on the respective frame-like members of the step ladder of the invention, the members 120 comprising resilient clip formations that can clip onto pin formations 122, to releasably hold the frame-like members together. Clearly, to permit release of the frame-like members for their displacement into their operative configuration, sufficient manual force must be applied between them in order to permit release of the complementary clipping formations from one another. A magnet arrangement clearly can be similarly employed for the purpose.

The overall configuration of the step ladder of the invention as above defined and described clearly is greatly variable and the invention extends also to all such variations of step ladders that still incorporate the main principles of the step ladders 10, 50 and 60 as herein described. It will be appreciated that the step ladder will be relatively safe to use, particularly insofar as the extension member will permit a person standing on a rung of the ladder to physically hold onto the extension member for additional stability. By supporting tools, and the like, on the support formation of the extension member, performing of different tasks while using the step ladder also can be greatly facilitated.

Claims

1. An A-frame step ladder, which includes

two hingedly connected frame-like members having collapsible stay members acting between them for defining the operative A-frame configuration of the step ladder, one of the frame-like members including a pair of spaced apart stiles, cross members forming the rungs of the step ladder secured between the stiles and two elongate, substantially parallel, spaced-apart guide formations extending substantially along the length of the respective stiles;

2. An A-frame step ladder as claimed in Claim 1 , in which the stiles of at least the frame-like member carrying the cross members forming the rungs of the step ladder are downwardly splayed and in which the guide formations are secured to the frame-like member adjacent its respective stiles in a substantially parallel, spaced apart configuration with respect to one another.

3. An A-frame step ladder as claimed in Claim 1 , in which the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder define segments that are disposed substantially parallel to one another and in which the guide formations are carried by the stiles in the region of the substantially parallel segments thereof.

4. An A-frame step ladder as claimed in Claim 1 , in which the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder define segments that are disposed substantially parallel to one another and in which the stiles themselves serve as the guide formations in the region of these segments.

5. An A-frame step ladder as claimed in Claim 3 or Claim 4, in which operative bottom end segments of the respective stiles of the frame-like member carrying the cross members forming the rungs of the step ladder are downwardly splayed, forming feet for this frame-like member that are spaced apart further than the spacing between the substantially parallel segments of the stiles.

6. An A-frame step ladder as claimed in any one of Claims 3 to 5, in which the stiles of the frame-like member carrying the cross members forming the rungs of the step ladder comprise elongate extruded sections.

7. An A-frame step ladder as claimed in any one of the preceding claims, in which the guide formations are in the form of one of channel sections and rectangular box sections.

8. An A-frame step ladder as claimed in any one of the preceding claims, in which the locating means includes, pivotally mounted on at least one of the support arms of the extension member, a spring biased catch formation which, in a predetermined operative position of the extension member in which the support formation is elevated above the top end of the frame-like members, is biased into a position in which it engages a formation defined by the guide formation in which the support arm is slidably displaceable, for preventing displacement of the support arm towards its inoperative position.

9. An A-frame step ladder as claimed in Claim 8, in which the spring biased catch formation serves to locate the support formation of the extension member in different predetermined operative positions.

10. An A-frame step ladder as claimed in Claim 8 or Claim 9, in which the locating means includes a spring biased catch formation pivotally mounted on each of the support arms of the extension member.

1 1. An A-frame step ladder as claimed in any one of Claims 8 to 10, in which each support arm of the extension member on which a spring biased catch formation is pivotally mounted is one of an elongate rectangular box section and a channel section within which an aperture is defined that, upon displacement of the extension member into a predetermined operative position, is positioned in register with an aperture defined in the guide formation to thereby provide for the catch formation to be biased into a position in which it engages the guide formation via the aperture, to hold the extension member in the operative position.

12. An A-frame step ladder as claimed in any one of Claims 8 to 1 1 , in which each spring biased catch formation of the locating means has a displacement means operatively linked therewith in a configuration in which it is externally accessible on the ladder for displacing the catch formation into a release position, in which the extension member can be displaced towards its inoperative position.

13. An A-frame step ladder as claimed in Claim 12, in which the displacement means comprises a cable element connected to the catch formation and a lever that is externally mounted on the ladder in a configuration in which it can act on the cable for displacing the catch formation connected thereto into a release position.

14. An A-frame step ladder as claimed in any one of the preceding claims, which includes trap means for trapping at least one of the support arms of the extension member within its guide formation in a configuration in which the support arm cannot be pulled from its guide formation.

15. An A-frame step ladder as claimed in Claim 14, in which the trap means comprises a spring biased catch formation pivotally mounted on a support arm in a configuration in which it is operable to engage a formation defined by the guide formation in which it is displaceable and that is positioned in a location in which the extension member is prevented from further displacement from its inoperative position.

16. An A-frame step ladder as claimed in Claim 14 or Claim 15, which includes release means that is operable to render the trap means ineffective, thereby to permit the extension member to be separated from the remainder of the ladder by its support arms being pulled from their respective guide formations.

17. An A-frame step ladder as claimed in any one of the preceding claims, which includes locking means for locking the extension member in its inoperative position when the frame-like members of the ladder are collapsed, the locking means comprising a spring biased locking pin located on a stile adjacent a guide formation carrying a support arm of the extension member.

18. An A-frame step ladder as claimed in Claim 17, in which, with the extension member positioned in its inoperative position and upon collapse of the frame-like members, the frame-like member not carrying rungs will act on the locking pin for its engagement with registering holes in the guide formation and support arm, slidably displaceable therein, for holding the extension member in its inoperative position.

19. An A-frame step ladder as claimed in any one of the preceding claims, which includes a holding arrangement for releasably holding the frame-like members in their collapsed configuration.

20. An A-frame step ladder as claimed in any one of the preceding claims, which includes a foot platform that is displaceably locatable between the rung operatively beneath the top rung of the frame-like member carrying the rungs of the step ladder and the other frame-like member and that forms an extension of the said rung when so located.

21. An A-frame step ladder as claimed in Claim 20, in which the foot platform is pivotally mounted on the said other frame-like member to be pivotally displaceable between an inoperative configuration, in which it is folded into the general plane of the frame-like member on which it is mounted, and an operative configuration, in which it cooperates with a support formation on the frame-like member carrying the rungs, for supporting the platform in its configuration in which it forms an extension of the said rung.

22. An A-frame step ladder as claimed in Claim 21 , which includes a holding arrangement for releasably holding the foot platform in its inoperative configuration.

23. An A-frame step ladder as claimed in Claim 1 , substantially as herein described with reference to and as illustrated in the accompanying drawings.