GB2218451A

GB2218451A - Step ladder

Info

Publication number: GB2218451A
Application number: GB8811143A
Authority: GB
Inventors: Raymond Skellard
Original assignee: Beldray Ltd
Current assignee: Beldray Ltd
Priority date: 1988-05-11
Filing date: 1988-05-11
Publication date: 1989-11-15
Anticipated expiration: 2008-05-11
Also published as: GB8811143D0; GB2218451B

Abstract

A step ladder has a ladder 10 pivoted to support legs 16, with a wire tie 30 for limiting the angle of hinging, the tie being pivoted to the ladder stile 10 and having a loop 32 to slide on the leg 16 from an abutment 22, when the step ladder is erected for use, downwardly along the leg when the step ladder is folded for storage. <IMAGE>

Description

STEP LADDER A conventional step ladder comprises a ladder having a pair of stiles and a plurality of steps extending between the stiles, and a second pair of stile-like members to form support legs connected together by one or more cross pieces and hinged to the ladder stiles so that, in use, the step ladder forms an inverted Vee when viewed in side elevation.

Tie members are provided at one or both sides to limit hinging movement. Usually the tie consists of a hook pivoted on one and engageable with the other of the stile and stile-like member at one side of the ste ladder. However, a careless user may omit to engage the hook, and the steps are then unsafe. AnothEr form of tie which avoids this risk comprises a pair of links pivoted together and also pivoted to the stile and leg so that they can fold to a parallel position when the stile ano leg are parallel, and extend generally co-linearly when the stile and leg are at a maximum angle to one another.

This tie is automatically brought into use, but in oroer to prevent it collapsing back to the folded position with unintentional closing cf the step ladder, it is usual to have an over-centre action on the links, making them into a rigid strut. This strut may then transmit load fro the ladder to the legs in an undesired fashion, which makes it necessary to increase the rigidity of the stiles and legs to cope with this, making the construction more expensive. It also creates problems in folding and stowing the step ladder because the better and more reliable the over-centre action the more difficult it is to intentionally fold the links and collapse the ladder.

Yet another known form of tie uses a slotted link pivoted to one of the stile and leg and permanently engaged with the other. This too may be automatic in use, but subject to the same disadvantages of the other forms of tie mentioned to lesser degree, that is it must be positively engaged in the extended position in order for the ladder to bE safe; the more difficult it is to disengage it accidentally then (probably) the more difficult it is to disengage it intentionally and it may transmit load in an undesired fashion. In addition it tends to be more expensive to produce.

The object of the invention is to provide a new tie which avoids these problems.

According to the invention, a step ladder comprises a ladder hinged to a pair of legs and one or more ties for limiting the angle of hinging each tie comprising a flexible member pivoted at one end to the ladder stile and looped about the corresponding leg in a manner permitting the loop to slide along the leg from first position when the ladder and leg are parallel to z second position next to an abutment when the ladder and leg are hinged apart to a maximum permitted extent.

Preferably the flexible member is of stiff wire which will be pulled straight in tension when the steps are in use, but which can bend under compression to limit transfer of load from ladder to legs.

The abutment may comprise 2 cross piece connecting the legs.

The invention is now more particularly describeo with reference to the accompanying drawings wherein: Figure 1 is a perspective view of a platform step ladder in a position for use; and Figure 2 is a side elevation of the same in the stowed or storage position.

Referring now the drawings, the ladder comprises a pair of stiles 10 made from a single length of tube and joined by a series of parallel steps 14.

A pair of legs 16 is hinged to the stiles at 18 and the legs are joined by cross pieces 20, 22, 24.

The stiles extend above the pivotal axis 18 at 36 where they are joined together by the portion 12. This may provide a safety rail for the user.

A platform 26 is provided spaced above the top step 14 by the same distance as the interval between successive steps. The platform is conveniently made as a metal pressing with a peripheral skirt. The skirt is apertured coaxially near one edge and the apertures are threaded by a cross piece 28 fixed to the stiles at an appropriate position. The skirt is also provided with coaxial open ended slots near its opposite edge and which can engage with the cross piece 24 on the legs. However, the arrangement could be reversed with the platform pivoted on 24 to the legs and engaging with the cross piece 28 to the stiles.

The platform serves as a lock in the Figure 1 position to hold the step ladder as illustrated. The platform can be lifted up at the rear to disengage it from the cross piece 24 to allow the collapsed Figure 2 position when the platform extends generally parallel to the bundle of stiles and legs.

However, it is considered that the locking effect provided by the platform is insufficient for safety.

Accordingly, a tie is provided at a lower position.

The tie which is duplicated, one to each set of stile and leg, comprises a wire or rod 30 pivoted to the stile 10 by having an end portion threaded through a hole through the stile for example made captive thereat. The opposite end of the tie 30 extends as an open loop 32 about the leg 16. The loop comprises portions extending along the inside and outside faces of the leg, which portions are inclined to one another. The effect is that the loop is a close sliding fit on the leg in both illustrated positions (Figure 1 and 2) although a looser fit between those two positions. If desired it can be a push fit along the stile.

The ladder can be moved from the Figure 1 to the Figure 2 position and vice versa without needing any manipulation (unless it is a push-fit) or engagement or disengagement of the ties which are, in this sense, automatic. Hence the prior art problems are avoided.

The ties are completely effective without it being necessary to positively engage them, and thus equally efficient when used by careless people. Because there is no separate engagement, there is no separate disengagement, and intentional collapse of the ladder is easy. Because the ties are flexible they will not transmit loads from stiles to legs or vice versa and an economical construction is possible. Because of the geometry of the arrangement, the ties remain in the Figure 1 effective position without any tendency to slip from that position.

Claims

1. A step ladder comprising a ladder hinged to a pair of legs and one or more ties for limiting the angle of hinging, each tie comprising a flexible member pivoted at one end to the ladder stile and looped about the corresponding leg in a manner permitting the loop to slide along the leg from a first position when the ladder and leg are parallel to a second position next to an abutment when the ladder and leg are hinged apart to a maximum permitted extent.

2. A Step ladder as claimed in Claim 1 and substantially as described Lith referencE to the accom?2nyir,c drawings.

2. A step ladder as claimed in Claim 1 wherein the flexible member is of stiff wire which will be pulled straight in tension when the steps are in use, but which can bend under compression to limit transfer of load from ladder to legs.

3. A Step ladder as claimed in Claim 1 or Claim 2 and substantially as described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A step ladder comprising a ladder hinged to a pair of legs and one or more ties for limiting the anode hinging, each tie comprising a flexible member of stiff wire pivoted at one end to the ladder stile and looped about the corresponding leg in a manner permitting the loop to slide along the leg from a first position when the ladder and leg are parallel to a second position next to an abutment when the ladder and leg are hinged apart to a maximum permitted extent, so that the flexible members will be pulled straight in tension when the steps are in use but can bend under compression to limit transfer of load from ladder to leos.