EP0330642B1 - Mobile ladder basket - Google Patents

Abstract

The basket comprises claws (1, 2) for support on a ladder (15) capable of being disengaged under the effect of an upward traction transmitted by means of a movable bar (3) and a spring (5). A locking means is provided which is capable of engaging the claw in the support position by a downward movement of a bar (4) which is movable with respect to the chassis of the basket. The locking means furthermore comprises a spring (6) attached on the one hand to the bar (4) and on the other hand to an element (9) integral with the basket, this spring being stretched or compressed when the claws (1, 2) are disengaged. <IMAGE>

Description

The present invention relates to a nacelle capable of being adapted to a ladder and of being moved along it.

This type of nacelle can be used to perform various works on building facades, more particularly for washing windows from the outside of a building or for maintaining a facade. The ladder for this purpose is preferably suspended from a rail, which can be placed permanently, which allows its lateral movement.

The nacelle according to the invention is conventionally constituted by a platform mounted on a chassis and comprising a guard rail constituted for example by one or more hoops. The chassis can move, like a trolley, along the ladder in an essentially vertical position.

The nacelle can be moved in height by sliding or rolling on the uprights of the ladder, preferably in the latter case by means of a set of rollers, possibly comprising appropriate grooves, and placed on either side amounts of the ladder, for example at the front and at the rear.

The nacelle will be held at a fixed height by one or more lugs or claws for blocking or support bearing on a rung and projecting from it. It will preferably be two claws situated at the ends of an element integral with the nacelle, for example a horizontal tube. The claws can partially pivot around a horizontal axis under the action of the operator in order to allow free movement, up or down, of the nacelle. The claws can then be released when the basket is at the desired height.

The nacelle according to the invention has the particularity of offering an improved level of security compared to other known devices.

The invention generally provides a safety device for a mobile basket along a ladder, characterized in that it comprises a spring (5) which, in its active state caused by an operator, releases the means for blocking the basket, in order to allow its free upward or downward movement, and simultaneously drives a second spring (6) from its passive state to its active state, second spring (6) whose effect is to reengage the locking means either under the stress of an operator either in case the first spring is no longer used.

According to a particular embodiment of the invention, there is provided a mobile nacelle on the uprights of a ladder characterized in that it comprises one or more support claws (1,2) on a rung (15) capable to be disengaged, in order to allow free upward or downward movement of the nacelle, under the effect of an upward traction transmitted via a movable bar (3) and a spring (5) . The nacelle comprises a locking means capable of engaging the claw (s) in the support position by downward movement of a bar (4) movable relative to the chassis of the nacelle, said locking means further comprising a spring ( 6) attached on the one hand to the bar (4) and on the other hand to an element (9) integral with the nacelle. The spring will be stretched or compressed when the claws (1,2) are disengaged.

The nacelle according to the invention is characterized in fact by the presence of a safety blocking mechanism which prevents the nacelle from falling if, during a movement maneuver along the ladder, the operator releases the traction means which 'it operates.

In more detail, when the height on the ladder must be modified, the operator places himself on one of the upper rungs and pulls vertically on a bar, possibly provided with a rope or other equivalent means of traction. Said bar drives through a first spring the unlocking of the claws by rotating the axis on which they are fixed. The unlocking of the claws being acquired, these being out of the level of the rungs, the bar then drives the nacelle in its upward or downward movement. Said bar in fact comprises a lateral buttonhole whose length is calculated so that the lower part forming a stop, following the aforementioned movement, comes into contact with an element secured to the nacelle. The gondola is then free to slide or roll along the ladder uprights. The operator manually lowers or lifts the traction means and therefore the platform.

When the platform has reached the desired height, that is to say for example at a level immediately above or below the initial level, the operator while maintaining a force to retain the platform, actuates a second vertical bar by exerting a downward pressure, preferably with his foot, to bring the claws into the locking position using the device described below with reference to the drawings. The lifting force can then be interrupted and the nacelle will take support, via the claws, on the desired rung. The operator can then take place on board the nacelle to carry out his work.

If by accident, the operator releases the traction means during the operation of moving the nacelle, a second spring which has been stressed by traction or compression during the unlocking operation, and which is therefore less strong than the first, immediately returns the claws by pivoting to the locked position. Therefore, the reaction time being very short, the fall distance of the nacelle will generally not be greater than the height separating two steps.

According to the present invention, therefore, a mobile nacelle is proposed on the uprights of a ladder comprising support claws on a rung capable of being disengaged under the effect of an upward traction transmitted by the intermediary a movable bar and a spring, and a blocking means capable of engaging the claw in the support position by downward movement of a bar, said blocking means further comprising a spring attached on the one hand to the bar and secondly to an element integral with the nacelle, a spring which will be stretched or compressed when the claws are disengaged.

The invention will be better understood by referring to the drawings provided by way of non-limiting examples.

Figure 1a is a perspective view of the movement mechanism of the nacelle, the latter being in the rest position. The bar 4 is in partially broken view showing the internal spring 6. The blocking effected on one of the steps is shown in side view in FIG 1b; according to a section passing through the middle of the rungs.

Figure 2a is the corresponding view of said mechanism in the free position, that is to say after unlocking the claws by folding as shown in side view in Figure 2b, and therefore being able to slide freely under the action of the operator.

Figure 3 is a view of said mechanism in the locking position at a height which, after movement along the uprights, may be different from that illustrated in Figure 1. The nacelle now rests on the rung 15 ′.

The nacelle according to the invention and the operation thereof are described below in more detail with reference to these drawings.

Figure 1 illustrates the mechanism of the invention at rest, the scale and the non-active elements of the nacelle being shown in dotted lines. The claws 1 and 2 are supported on a rung 15 and the nacelle rests on the scale by gravity. Note the presence of a first spring 5, of the vertical bar 3 in tubular form and comprising two lateral buttonholes 11 and 11 ′ of sufficient length not to drive the elements 9 and 10 integral with the nacelle before the complete disengagement of the claws . The upper ends of the buttonholes rest on the elements 9 and 10. The spring 5 is fixed on the bar 3 on the one hand and on the other hand on a horizontal bar 7 secured to the claws 1 and 2, by means of the arms 13 and 13 ′ but located on the other side of the horizontal bar 9 acting as a tilting axis. The extensions 21 and 21 ′ of the bar 7 rest on the frame of the nacelle and therefore prevent the bar 7 from tipping down. Bars 7 and 9 are approximately in the same plane. By pulling upwards the bar 7 is therefore capable of tilting said claws 1 and 2 out of the plane of the steps.

Similarly, the bar 4 also comprises two buttonholes 12 and 12 ′ of the same height and crossed respectively by the elements 10 and 9. In the vicinity of the lower end of the bar 4 is a lug or an angle 8 bearing on the bar 7.

The nacelle is therefore at rest bearing on the rung 15 by means of the locking claws 1 and 2 and maintained along the uprights, in this embodiment, by the 8 casters 16.

According to a particular embodiment and not illustrated, the spring 6 rests on the bottom of the bar 4, below the horizontal element 9.

Figure 2 illustrates the nacelle according to the invention in the free position, it can then move up or down freely along the uprights of the ladder. The operator pulled the bar 3 vertically upwards (arrow A), for example by means of a cord fixed to the eyelet present at the upper end of this bar. In doing so the spring 5 rotated the bar 7 (arrow C) as well as the arms 13 and 13 ′ and the claws 1 and 2 have tilted, thus no longer resting on a rung. The bar 7 is in fact capable of pivoting upwards around the axis constituted by the bar 9 to an extent just sufficient to disengage the claws, that is to say place them outside the plane of the rungs. The elements 9 and 10 initially in the upper parts of the buttonholes find themselves in abutment with the lower parts and the nacelle integral with these elements is therefore suspended by the traction means 3. The nacelle can be lowered or mounted at the discretion of the operator (arrow B) which is on one of the upper rungs of the ladder. The pivoting to disengage the claws 1 and 2 has driven the bar 4 upwards via the angle iron 8. The spring 6 fixed on the one hand to this bar 4 and on the other hand to the element 9 integral with the basket is then stretched.

It will be understood that the spring 5 must be able to tension the spring 6 and therefore must have a higher restoring force.

According to the particular embodiment already mentioned for FIG. 1, at the stage described in FIG. 2, the spring 6 is compressed between the bottom of the bar 4 and the horizontal element 9.

FIG. 3 illustrates the placing in the blocking position of the nacelle according to the invention, for example at another height corresponding to rung 15 ′ adjacent or not to rung 15. The operator does this while maintaining the bar 3 and thus supporting the weight of the nacelle, exerts a downward pressure on the bar 4 (arrow D) the latter descends and, by means of the angle iron 8, folds down the bar 7 bringing back the claws 1 and 2 in the blocking position on a rung 15 ′, different from 15. The bar 3 can then be released and the nacelle is blocked by gravity at the desired height. The operator can then go down there to do his work safely.

FIG. 3 also shows the presence of the spring 6, the function of which is, in the event of the bar 3 being released by the operator during an operation of moving the nacelle, to immediately return the claws to the blocking position. The spring 6, attached on the one hand to the bar 4 and on the other hand to the element 9 integral with the nacelle, will indeed immediately bring the bar 4 down, bar which by means of the angle 8 will swing the claws into the locked position.

FIG. 4 is an overall view of the complete nacelle 18 in the operating position on a ladder 17 suspended from a rail 19 and comprising at its base stabilization means 20.

The structure of the nacelle, and in particular that of the bars 3 and 4, is preferably tubular. It is for example made up of hollow aluminum tubes, square or rectangular. The whole of the nacelle is obviously preferably made of light metal, such as aluminum alloy.

The basket of the invention can weigh from 10 to 20 kg and can be separated from the scale, for example, by sliding it out of the upper end of the scale. The modular nature of the device is a significant advantage. For washing the windows of buildings, permanent rails are preferably provided so as to be able to fix a ladder and then a nacelle according to the invention.

Such a scale can measure up to 20 meters and more. At the lower end of the ladder, bumpers are preferably provided, preventing the lower wheels of the nacelle from going beyond the lower end of the uprights. Removable stabilization means mounted on casters can also be provided as shown in FIG. 4.

Other embodiments are possible, for example there may be several tubes 3 and 4. These tubes may not include buttonholes surrounding one or more parts of the chassis of the nacelle but sliding between two stops in a bearing secured to this chassis.

The examples and embodiments mentioned above are therefore not limiting. Many equivalent means can be envisaged by those skilled in the art without departing from the scope of the present invention as defined in the claims.

Claims (2)

1. Mobile ladder basket on the uprights of a ladder, characterised by the fact that it includes one or several support prongs (1,2) on a rung (15) which can be disengaged, in order to allow free upward or downward movement of the basket, as a result of a upward pulling action transmitted by means of a mobile rod (3) and of a spring (5), and a locking means able to engage said one or several prongs in supporting position by the downward movement of a rod (4) which is mobile towards the basket frame, whereby said locking means also includes a spring (6) connected on one hand to the rod (4) and on the other hand to an element (9) which is connected to the basket, whereby said spring (6) will be extended or compressed when the prongs (1,2) will be disengaged.
2. Safety device for mobile ladder basket characterised by the fact that it includes a spring (5) which , in its active condition caused by an operator, release the basket locking means in order to allow its free upward or downward movement and simultaneously brings a second spring (6) from its passive into its active condition, whereby this second spring (6) again engages the locking means either due to the action of the operator or in the case the first spring is no longer stressed.

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