FR2813918A1 - Ladder convertible into several levels comprising aluminum uprights and runner receiving spindle on fitting on uprights - Google Patents

Abstract

The ladder is able to be converted into several levels each comprising aluminum tubular uprights (20) connected to each other by rungs. At least one of the levels (18) other than the ladder lower level (19) comprise along their outer edges uprights and a runner (22) able to receive a spindle (23) provided on the fitting (1). The spindle is shaped into a female half-articulation of the lower level, opposite upright. This fitting comprises a quarter turn stop (9) for a wedge (10) which comprises the corresponding fitting shaped into a male half-articulation (11) on the other level, i.e. an intermediate or higher level able to slide on the lower level.

Description

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The present invention relates to a ladder which can be transformed into several planes, it being understood that by the expression "plan" is meant a rigid assembly made up of two uprights connected by parallel bars and in principle equidistant, making it possible to climb the ladder. The uprights can be parallel to each other, but the lower plan, the widest, can have non-parallel uprights in their lower part, namely uprights widening towards the outside going downwards, this to increase the stability of the ladder. These plans can be made of any material suitable for the use of these scales, in particular outdoors on construction sites, for example cold-machined steel or preferably extruded aluminum, this metal combining the desired qualities of rigidity, resistance to corrosion and lightness.

We know on the one hand the ladders with two articulated planes, which can be opened from foolish to be put in a freestanding position, and on the other hand the ladders with two or more sliding planes, convertible into single or double ladders.

In certain articulated ladders, the vertices of the two planes are connected to each other by a fixed hinge, with indexing or a notch making it possible to adjust the opening angle of the two planes, this angle being able to be further limited by at least one rope or strap passing or fixed on a bar of each plane at the bottom of the ladder, or by at least any rigid spacer, adjustable in length. The disadvantage of these ladders is that the two planes cannot dissociate from each other to form a sliding ladder.

Other articulated ladders are mixed, i.e. they can be transformed into single, double articulated ladders or

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 sliding ladders by a positioning search system. In these scales, the uprights of the upper sliding plane can carry two axes of articulation and can slide respectively in gussets articulated from the upper end of the uprights of the lower plane. The ladder can then be used as a sliding ladder, hooks from the upper plane, bearing on a selected bar from the lower plane, then determining, by blocking the sliding downwards, the useful height of the ladder. To use it on a double scale, just. slide the upper plane downwards after having released the hooks from their bar, and bring the aforementioned axes (or an upper bar of this plane which takes its place) into the housings of a female part intended for them at the upper part of the lower plane, as a result of which the two planes can pivot one after the other. The disadvantage of this system lies in the fact that it sometimes involves a delicate positioning maneuver, with the risk that at least one of the axes of the upper plane is positioned outside its housing on the lower plane, which can make the ladder dangerous and also cause deformation of the axis or the bar which takes its place. Even if the axes are well positioned in their housings, it can also happen that they come out accidentally under the effect of vibrations due to the user on surfaces other than the earth, making the assembly precarious and the still dangerous ladder.

The object of the present invention is to avoid all of these drawbacks of the prior art, and to produce a transformable ladder without risk of poor assembly, safe and of great ease of use while being economical in manufacturing.

To this end, the invention relates to a transformable ladder with several planes each comprising two tubular uprights of extruded aluminum connected to one another by bars making it possible to

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 climb the ladder, end caps being engaged at least in the upper ends of these uprights, in principle being non-slip serrated end caps, which can also be engaged in the lower part of the uprights of the ladder, so as such known.

According to the present invention, such a ladder is characterized in that at least the plane or planes other than its lower plane comprise, all along the external flanks of their respective uprights, a slide coming from extrusion and suitable for receiving a planned axis. on the upper endpiece, shaped as a female half-articulation, of the upright opposite said lower plane, this endpiece comprising a quarter-turn stop for a cleat that has the corresponding upper endpiece, shaped in male half-articulation, of the other plane, namely the intermediate or upper plane capable of sliding on said lower plane, the cooperation between said quarter-turn stop and said cleat of two facing ends being such that the sliding of the two planes one on the other, in the direction of an extension of the scale, is authorized as long as the two planes considered are practically applied one on the other, this sliding upwards of the plane s higher on the lower plane becoming impossible when the two planes of the ladder are moved apart and put in position of double articulated ladder.

We will see better below the operation and the advantages of such a scale. It can already be noted that the end pieces can be molded, exactly like the conventional non-slip end pieces, while additionally providing guidance and articulation functions of the two planes of the ladder one on the other. These nozzles may be made of any material suitable for their function, for example of thermoplastic material or aluminum molded or even machined in the mass,

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 in any case being a sufficiently rigid material, resistant to weathering and the effects of the sun.

Advantageously, the axis of the female articulation is capped by a sliding pad by means of which it can thus slide in the corresponding slide of the upright which carries the cooperating male articulation, which will prevent this axis, by steel principle, do not wear the walls of the slide.

It goes without saying that the two uprights of each plane of the ladder will be equipped in the same way, on the right and on the left, even if in what follows the upright is described only on one side, the arrangement being symmetrical on the other side.

A ladder according to the invention can also be characterized in that each end piece, carrying a male or female articulation, comprises on the one hand a foot of a width such that it can engage alone exactly in the end d '' a tubular upright of standard width, and on the other hand a lug having together with the foot a width greater than the previous one, so that the foot and its lug can engage together exactly in the end of a tubular upright also standardized in width, significantly greater than the previous one.

In this way we can mount the same tips on amounts of significantly different widths, which will simplify the manufacture of scales.

These ends can be snapped onto the uprights or be fixed there by screwing or any other means.

Embodiments of the invention will now be described by way of non-limiting examples with reference to the figures in the attached drawing in which

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 - Figure 1 is a perspective view of the inner part with quarter-turn abutment of an external female half-articulation of ladder, intended to equip the upright of a lower plane with a transformable ladder conforming to l invention; FIG. 2 is a perspective view of the external part with cleat of an internal male half-articulation of a ladder, intended to equip the upright of an intermediate or upper plane with a transformable ladder according to the invention, this amount carrying along its outer flank a slide for the axis of the outer female half-joint of Figure 1; - Figure 3 is a perspective view of a sliding pad suitable for engaging on the axis of articulation of an external female half-articulation to be interposed between this axis and the corresponding slide of the upright carrying the inner male half joint; - Figure 4 is an elevational front view, and on the side of their inner faces, of the mounted assembly of two half-joints, male and female, usable for a transformable ladder with two articulated planes, in an alternative embodiment of the end pieces ; - Figure 5 is a partial perspective view of the upper part of a transformable ladder according to the invention, of the type with two planes which can be articulated or slide in on the other; - Figures 5a and 5b are side elevation views, and schematic, showing a two-plane ladder

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 respectively in the sliding position and in the pivoting position; and - Figure 6 is a side elevational view of another transformable ladder according to the invention, comprising three planes including a lower plane, an intermediate plane and an upper plane, the first two being articulated one on the 'other and the three plans that can together constitute, moreover, a sliding scale of great development.

In FIG. 1, the end piece 1 made of mat; molded thermoplastic era comprises a right foot 2, here without additional tab, and has a width such that it allows it to be adjusted in the open upper end of an upright in extruded aluminum of corresponding width, constituting one of the elements of a transformable metallic ladder lower plane. The attachment of the end-piece 1 on the corresponding amount can be ensured by any means appropriate to its function, for example screws or a crimp, Line cut-in re-entering tab of the metal which can penetrate into a housing of the end-piece, such as that which is visible at 5. This end piece 1 has at 3 a hole for the reception of a round metal axis, for example steel, intended to constitute a pivot axis of the two planes of the ladder and at the same time to slide in the slide continuous that has the outer face of an amount of extruded aluminum corresponding to the inner plane of the scale, namely an intermediate or upper plane, intended to be articulated and to slide on the aforementioned lower plane. Preferably and as already indicated above, this axis carries a sliding or intermediate friction shoe 4, shown in FIG. 3, of a thickness corresponding to the width of the aforementioned slide and which will avoid any metal-to-metal friction between the axis and this slide. Note in Figure 3 that the sliding pad 4

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 has two holes 6 and 7. These two holes can receive one end of the aforementioned steel axis, the other end of which will be received by hole 3 of the end piece. In principle, the upper hole 6 will be used for an articulation between a lower scale plane and an intermediate plane, and the lower hole 7, located approximately in the middle of the shoe 4, for an articulation between an intermediate scale plane and a third upper plane, this for an optimal distribution of the forces. It should be noted that in the latter case the shoe 4 can pivot on its axis 3 in an arcuate space similar to that which is referenced at 8 in FIG. 1, which is also present on the side opposite to the outside face with the aforementioned cleat. of the male half-joint, that is to say on the inner side facing the median plane of the scale. This inner side of the male half-joint 11 of an intermediate plane therefore constitutes in itself a female half-joint.

In FIG. 1, there is also referenced in 9 what is called above the stop qli @ irt-de-tour, limiting the arcuate space 8 and intended to cooperate, in the manner which will be seen below, with the cleat 10 of the outer face of the male deini-articulation 11 shown in FIG. 2. In this figure, reference is made at 12 to a fixing foot similar to foot 2 and which can be fixed in a similar manner in the upper end of the upright corresponding. In 13 is also visible a straight housing adapted to receive the upper extremity of the sliding pad 4 when the ladder operates on a double articulated ladder, this pad then being at the upper end of the corresponding slide.

On the flLii-e 4 there is shown the variant according to which the foot 2, 12 proper key each tip, respectively 1, 11, is associated with a tab which is slightly spaced, respectively 14, 15, so that each tip can engage in amounts of widths

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 markedly different standardized: for small widths, only foot 2 or 12 is engaged in the upright, and for larger widths, foot 2 is engaged therein at the same time as leg 14, and foot 12 at the same time as the lug 15. In the first case, it is without disadvantage that the lugs 14 and 15 remain outside the upright.

Figure 4 shows the two end pieces 1 and 11 in a relative position corresponding to the complete folding of the two planes of the ladder against each other. We see that there is then a space of freedom e between the quarter-turn stop 9 of the female half-joint 1 and the cleat 10 of the male half-joint 11. This space makes it possible to slide upwards. the upper or intermediate scale plane, which carries at the top of its uprights the two male half-joints 11, when it is desired to use the scale on a sliding scale (FIG. 5a). By cons we understand that from the folded position of Figure 4, if we move one from the other the two planes of the scale, any sliding upward of the interior plane carrying the tips 1 1 will be prohibited, since then the tabs 10 will come to a stop on the quarter-turn stops 9 of the end pieces 1 of the other plane; the ladder can only be used in a double articulated ladder, without any danger of the two planes sliding relative to each other (fig. 5b).

Figure 4 also shows, on the inner face of the male half-joint 11, two other pin holes 16 and 17 having the same role as the hole 3 to receive another guide axis of an upper plane of scale on the intermediate plane, this axis then being able to slide, with or without friction pad, in a slide which comprise, on each of their external faces, the uprights of this upper plane. The presence of two holes is motivated by the fact that one must be able to use

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 amounts of different widths: hole 16 will be used for larger amounts, and hole 17 for narrower amounts.

In FIG. 5, the internal plane 18 of the ladder, narrower than the external and lower plane 19 and intended to slide up on the latter or to be able to pivot therein, has been shown even narrower than it is is actually, to make the drawing clearer. The uprights of these two planes have been referenced respectively in 20 and 21, the uprights 20 of the interior plane being provided on their outer faces with slides coming from extrusion, one of which is visible at 22 and which terminate in the straight housings 13 mentioned above, provided for the reception of the axes 23 or if necessary of the pads 4 when the internal plane 18 is in the low position. These slides slide the axes 23, here devoid of friction pads, female half-articulations 1 fixed to the upper ends of the uprights 21.

It should be mentioned here that a ladder in accordance with the invention can incorporate known arrangements, such as that of using the bars 24 of the lower plane 19 to retain hooks 26 therein of the interior plane 18 and thus maintain this last at the desired height after sliding upwards, along the uprights 21 of the lower plane 19 (see Figure 6), or even that of using a rope or strap between the lower bars of the two planes 18 and 19 when the ladder is used as a double articulated ladder.

I1 it should be noted that the above-mentioned hooks 26 can be associated with a lock making it possible to lock them on the selected bar 24, which requires a maneuver: voluntary by the user to slide the one over the other. scale key shots.

It should also be noted that the upward sliding of any upper plane of the ladder on a lower or base plane can be stopped by

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 a screw or the like protruding into a slideway of this upper plane and which can come to a stop on the axis or sliding shoe of the cooperating lower plane. This sliding limitation could also be obtained by means of a strap or rope, possibly the same as that which serves to limit the spacing of the planes in an articulated ladder.

In 1 ïgui-e 6 there is shown a ladder with three planes, namely a lower plane 19, an intermediate plane 18 and an upper plane 25. We used the same references as in the previous figures, assuming that the planes 18 and 19 were the same as those already described. Thus the planes 18 and 19 are articulated one on the other, the intermediate plane 18 being able to slide therein further, while the upper plane 25 can also slide on the intermediate plane 18 and be blocked in height on the latter by hooks 27 similar to the hooks 26, engaging on the bars 28 of the intermediate plane 18. It should be noted that in this case and as already indicated above, the friction pads 4 mounted sliding in the slides of the uprights 29 of the upper plane 25 are engaged by their central hole 7 on one end of the steel axis such as 23 which is also engaged in one of the holes 16 and 17 provided on the inner face of the male half-joint 11 of the intermediate plane.

It should also be emphasized that the upper plane 25 not comprising, at the top of its uprights 29, half-joints similar to the half-joints 1 and 1 1 but only ordinary end pieces 30, will not risk pivoting on the intermediate plane 18, thus avoiding any danger of improper use of the ladder.

In addition to solving the problems encountered on the scales of the prior art, a scale in accordance with the invention will be more rigid without increasing the weight of material, due to the presence, on most of its amounts, slides to increase them

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 inertia and this without increasing its manufacturing cost since the uprights are produced by extrusion.

In terms of safety, it should be noted that the ladder cannot be used freestanding from a sliding position, since the two planes concerned cannot then pivot one after the other around a rigid joint: the axis 23 will then necessarily slide in the corresponding slide.

In addition, the pivot axes such as 23 will no longer undergo the bending forces encountered on other scales, because the limitation of opening planes in use on a double scale is done by a rope or strap , and not by flanges provided at the top of the uprights, generating forces on the axes.

It should be noted that the interior side of the last male articulation 11 of an intermediate plane constitutes a last female articulation for the corresponding internal plane, this latter female articulation being devoid of any stop qLiart-de-toLir-.

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Claims (7)

1. Convertible ladder with several planes each comprising two tubular uprights of extruded aluminum connected to one another by bars making it possible to climb the ladder, end pieces being engaged at least in the upper ends of these uprights, characterized in that that at least the plane or planes (18) other than its lower plane (19) comprise all along the outer flanks of their respective uprights (20) a slide (22) coming from extrusion and suitable for receiving an axis (23 ) provided on the end-piece, shaped as a female half-articulation (1), of the facing upright (21) of said lower plane (19), this end-piece (1) comprising a quarter-turn stop (9) for a cleat (10) that comprises the corresponding end-piece, shaped as a male half-articulation (11), of the other plane, namely of the intermediate (18) or upper plane capable of sliding on said lower plane (19), the cooperation between said quarter-turn stop (9) and said cleat (10) being t it that the sliding of the two planes (18, 19) one on the other, in the direction of an extension of the scale, is authorized as long as the two planes considered (18, 19) are practically applied the one on the other, this sliding becoming impossible when the two planes (18, 19) of the ladder are moved apart and put in the position of a double articulated ladder. 2. Eclielle according to claim 1, characterized in that the axis (23) of the female articulation (1) is engaged on a sliding pad (4) by means of dLiquel it can thus slide in the slide (22 ) corresponding. 3. Eclielle according to claim 1 or 2, characterized in that each end piece (1, 11), carrying a male or female articulation, comprises on the one hand a foot (2, 12) of a width such that it can engage alone exactly in the end of a tubular upright (20, 21) of width <Desc / Clms Page number 13>  standardized, and on the other hand a tab (14, 15) having together with the foot- (2, 12) a width greater than the previous one, so that the foot and its tab (2, 14; 12, 15) can engage together exactly in the end of a tubular upright (20, 21) of width also standardized, substantially greater than the previous one. 4. Ladder according to any one of the preceding claims, characterized in that a sliding plane (18) can be blocked in height on the lower plane (19) by lockable hooks (26) suitable for being retained on a selected bar (24) of said lower plane. 5. Ladder according to any one of the preceding claims, characterized in that the opening of the ladder used in a double articulated ladder is limited by at least one rope or strap passing or fixed on a bar of each plane (18, 19 ) at the bottom of the ladder, or by at least one rigid spacer adjustable in length. 6. Ladder according to any one of the preceding claims, characterized in that the sliding upwards of any upper plane (18) of the ladder on a lower or base plane (19) can be stopped by a screw or the like protruding into a slide (22) of this upper plane (18) and being able to come to a stop on the axis (23) or sliding shoe (4) of the lower plane (19) cooperating. 7. Ladder according to any one of the preceding claims, characterized in that the internal side of the male half-joint (11) of an intermediate plane constitutes a female half-joint for the corresponding internal plane, this female half-joint being devoid of quarter-turn stop.