FR3029560A1 - APPARATUS FOR ENABLING LOWERING AND RESTORING A SCALE IN A CONFINED ENVIRONMENT - Google Patents

Abstract

The present invention relates to an apparatus (100) for allowing the descent and the ascent of a ladder in a confined environment, comprising a box (200) for attachment to the apparatus on a supporting structure, said box comprising two slides (G1, G2) turned vis-à-vis and intended to allow the sliding of the two uprights (Mt) of a scale (Ec), a locking means for each bar (Br) of said scale. According to the invention, the locking means (300) comprises a latch (Lq) movable between a locking position of said bar where said latch is disposed between the two rails (G) and a retracted position where said latch is clear of the passage of the bars between the two slides, the latch being connected to a pedal (Pl). When the box is fixed on a supporting structure, for example, on a slab nose disposed under an access door to the confined environment, the operator can thus engage a ladder between the two rails of the box and control using of the pedal, its movement and in particular its movement of descent into the confined environment. The risk of accidents in such cramped areas is reduced.

Description

The present invention relates to an apparatus for allowing the descent and the ascent of a ladder in a confined environment, for example a tank, a raising station in a sewerage network, a sump. To access to a confined underlying location, such as a cistern, it is known to use a sliding device to move a ladder down into the underfloor volume to allow a person to access it so that it can achieve an intervention, then to scale up after the intervention. The device is in principle placed in a look, commonly called manhole, this access is normally closed by a hatch, a grid to prevent access to any unauthorized person. Such a device is shown in FIG. 1. It consists of a pair of slides G1, G2, U-section, facing vis-à-vis and between which can slide the two uprights of a scale, not shown. The two slides G are held by means of two cylindrical bars B fixed by welding inside the two slides. A sleeve M is rotatably mounted around the upper bar. A hook C is fixed on said sleeve to hang a bar of the ladder, to retain it during its downward movement. It consists of a lower part which ends in a hook shape and a high part forming a lever for maneuvering the hook, that the operator maneuver the foot forward, as suggested by the arrow A. A l use, the presence of the hook hinders the operator when using the ladder. The safety of attachment is perfectible, because an unfortunate maneuver of the hook is enough to depend on the scale which descends suddenly at the risk of injuring a person, to damage equipment. Knowing this state of the art, the applicant sought a solution to safely lower and raise a ladder in a confined environment. For this purpose, there is provided an apparatus for allowing the descent and the ascent of a ladder in a confined environment, comprising a box for fixing the apparatus on a supporting structure, said box comprising two slides turned vis-à- screw and intended to allow the sliding of the two amounts of a ladder, a locking means for each bar of said ladder; according to the invention, the locking means comprises a latch movable between a locking position of said bar where said latch is disposed between the two slides and a retracted position where said latch is clear of the passage of the bars between the two rails, the latch being connected to a pedal.

When the box is fixed on a supporting structure, for example, on a slab nose disposed under an access door to the confined environment, the operator can thus engage a ladder between the two rails of the box and control at the same time. the pedal, its movement and in particular its descent movement in the confined environment. The risk of accidents in such cramped areas is reduced. According to an additional feature of the invention, the locking means is provided with a latch return means to its locking position, in the absence of action on the pedal. The latch remains active without operator intervention. The ladder engaged 10 between the slides of the box remains blocked by its low rank bar bearing on said latch. According to an additional feature of the invention, the latch comprises a vertical wing, in the laying position of the box, mounted in an articulated manner on a slide, extended perpendicularly by a wing arranged obliquely upwardly and outwardly in the locking position of said latch, and which exceeds the vertical wing, to form with the vertical wing a V-shaped cradle on which can support a bar of a ladder, the oblique wing used to raise the latch to disengage under the effect of raising a bar of said ladder between the two slides.

The latch is automatically retracted on the ascent of the ladder to facilitate its extraction from the confined environment and to prevent the accidental fall of a ladder element in the confined environment. According to an additional feature of the invention, the box has in section a U-shaped geometry defined by an intermediate wall for fixing 25 said apparatus, extended perpendicular to its two edges of two side walls on which are retained the two slides. The box is relatively simple and economical to manufacture. According to an additional characteristic of the invention, the two slides are respectively fixed on two flanges mounted on the two side walls, the box being provided with means for adjusting the position of the two flanges so as to be able to modify the position of the two slides. . It is thus possible to position the slides to correctly place a ladder in the confined environment, to pass it through a fall arrest bar or to adjust the size of the box to the dimensions of the access window towards said confined environment. According to an additional feature of the invention, the pedal comprises a rod slidably mounted in a substantially vertical direction in a bracket fixed to one of the side walls or one of the flanges, the lower end of said rod being hingedly mounted on the vertical flange of the latch to maneuver between its two extreme positions. Maneuvering down on the pedal is a natural gesture and easy to practice.

According to an additional feature of the invention, a bracket, equipped with a winch, is mounted on the box to move down or up a ladder between the two rails. The installation and especially the removal of a ladder from the confined environment are less tiring to implement.

According to an additional feature of the invention, the apparatus comprises a ladder. The device can be marketed with a scale. Advantageously, the scale consists of at least two elements, an upper element, a lower element, the two uprights of one element being provided with two sleeves respectively capable of being nested in the uprights of the other element, the ladder being provided with at least one retaining means for mutually joining the two elements of the ladder. A relatively long ladder can be moved down and up in the confined environment from a narrow access. The ladder is preferably assembled during its descent into the confined environment. The ladder remains perfectly rigid. The elements of the ladder are disassembled during its lifting while it rests by a bar on the latch. According to an additional feature of the invention, the sleeves are provided with lateral pins sized to slide without mechanical play in the uprights. The elements of the ladder are assembled without play. The ladder remains stable to use. The characteristics of the invention mentioned above, as well as others, will emerge more clearly on reading the following description of an exemplary embodiment, said description being given in relation to the attached drawings, among which: FIG. 1 is a perspective view of an apparatus for allowing the descent and ascent of a ladder in a confined environment and known in the state of the art, FIG. 2 represents a perspective view of an apparatus intended to allow the descent and ascent of a ladder in a confined environment according to the invention, FIG. 3 is a plan view of an apparatus for allowing the descent and ascent of a ladder in a confined environment according to the invention; FIG. 4 shows an exploded view of two elements constituting a ladder for an apparatus allowing the descent and the ascent of a ladder in a confined environment according to the invention and FIG. 5 is a perspective view of a detail showing a locking mechanism of a ladder in an apparatus for allowing the descent and ascent of a ladder in a contained environment according to the invention. The apparatus 100 shown in FIG. 2 is intended to allow the descent and the ascent of a ladder in a confined environment. The apparatus 100 is in principle placed at a level that opens into the upper part of the confined environment. To understand what a confined environment is, we can refer to the definition of the INRS (National Institute of Research and Security) in its brochure ED 6026. The confined space is a space totally or partially closed: 1. That is not designed and constructed to be occupied by or intended to be occupied by persons, but which on occasion may be temporarily occupied for the performance of work such as inspection , maintenance or repair; 2. Who has restricted means of access, preventing air from circulating freely; 3. In which the atmosphere may present risks to the health and safety of anyone entering it, due to: - either insufficient natural or mechanical ventilation, 30 - or substances or substances it contains - either of its design or location, - the equipment used therein, or - the nature of the work carried out therein.

The apparatus 100 of the invention comprises a box 200 carrying two slides G1 and G2 allowing the sliding of a scale Ec, a mechanism 300 for blocking the scale. The apparatus may further optionally include a bracket 400 provided with a winch 420 for operating said ladder.

In FIG. 3, the box 200 consists of a plate 210 folded so as to present a top view of a U-shaped geometry, two flanges 230 against which are respectively fixed two slides G1 and G2. The plate 210 is intended to be fixed to a supporting structure, for example a slab nose. A closure hatch, not shown, is in principle fixed on the eye, 10 to oppose the fall of people or objects inside the confined environment. It is padlocked to limit access to the confined volume to only authorized persons. It can be supplemented with a fall arrest bar consisting of articulated bars that the operator must lift to go down into the confined environment, while the hatch is open.

The plate 210 is formed of an intermediate wall 212 serving to fix the apparatus 100, extended perpendicularly to its two edges of two lateral walls 216 on which the two flanges 230 are respectively fixed. Each slider G has in section a The two slides G1 and G2 are turned facing each other so that the two uprights Mt1, Mt2 of a scale Ec20 can slide in both U-shapes. The position of the two flanges 230 can be fitted on the two side walls 216 to adapt the position of the ladder, its inclination, the geometry of the confined volume, the size of the access hatch to said confined volume, the presence of a bar. Holes or lumens pass through the walls 216 and the flanges 230 to receive tie rods, fixing bolts. Such lights are visible in FIG. 5. In a preferred embodiment, tangent or intersecting holes pass through the two side walls 216 so that the positioning of the flanges can be made accurately, that is to say virtually without play, and perfectly symmetrical so that the ladder can slide freely between the two slides without getting caught, even if the 30 tie rods, the bolts, are not tightened to the prescribed torque. In an alternative economic embodiment, not shown, the two rails are fixed directly on the inner faces of the two side walls. With reference to FIG. 2, at the end of the installation of the apparatus 100 in the access opening to the confined medium, the scale Ec can slide freely between the two 30 glanes G1, G2. The ladder consists of two Mt uprights joined by Br bars. It is manufactured preferably in an aluminum alloy to provide lightness and strength. It is constructed in a single element, as shown in this FIG. 2 or more elements.

This variant embodiment is shown in FIG. 4, which distinguishes an upper element Es and a lower element Ei in the structure of the scale Ec. The amounts Mt are manufactured in a hollow profile of polygonal section, and preferably rectangular. Two sleeves Mol and Mo2 are nested in the lower part of the two uprights Mtl and Mt2 of the upper element Es to be slipped into the upper part of the corresponding amounts Mtl and Mt2 of the lower element Ei so that the two elements E and Ei can be mutually reinforcing. The sleeves Mo have a polygonal section, and preferably rectangular, or as it appears in this FIG. 4, a section C. They are in this case manufactured in a sheet metal sheet shaped in three folds. They are provided with lateral pins Eg sized to slide without mechanical play in the uprights Mt of the lower element. The lateral lugs Eg are preferably cut in the sheet metal sheet before its conformage. The mechanical assembly of the two elements is achieved by means of 20 retaining means, consisting of a pair of articulated hooks Ct equipped with toggle maneuvering handles, commonly called "grasshoppers". The articulated hooks Ct are fixed on the inner faces of the uprights Mt of an element and here of the lower element Ei so as not to hinder the sliding of said uprights in the rails. The two articulated hooks Ct cooperate with two eyelets Oi disposed opposite one another, on the upper element Es, for example, formed of two perforated metal plates, shaped in a V-shape and welded to the internal faces of said uprights. The two elements Es and Ei form at the end of their assembly a ladder or part of scale, monobloc and rigid. With reference to FIG. 2, and to avoid the abrupt descent of the Ec scale into the confined environment in which the box 200 has been previously installed, the apparatus 100 has a scale blocking mechanism 300, designed to block one to a Br bars of said ladder during its sliding movement. The mechanism 300 is composed in FIG. 5, a latch Lq mounted in an articulated manner on one, G2, of the two slides G, a pedal Pl of operation 3029560 7 of said latch, between a locking position where it is arranged between the two slides G, on the trajectory of the bars Br, and a retracted position clearing the passage between the slides, leaving to scale the ability to slide freely between the two slides. The locking position is obtained without any action on the pedal, whereas the retracted position is implemented by an action of the operator's foot on said pedal. In FIG. 5, the latch Lq is presented in its blocking position. The latch Lq consists of an angled plate comprising a vertical wing Av in the position of use of the apparatus 100 and which extends perpendicularly through an oblique wing Ao, in the locking position of the latch 10 Lq, and protruding from the vertical wing Av extending outwardly in a rising direction, to form with the vertical wing Av, a cradle V on which can support a bar Br. The vertical wing Av is mounted by means of a hinge At held in a gusset, not visible, fixed on the slide G2, for example on one of the flanks 15 which constitute it. The pedal P1 consists of a rod Tg slidably mounted in a substantially vertical direction in a bracket bracket at right angles to one of the side walls 216 or as shown in this FIG. 5, of one, 230b, flanges 230. The lower end of the rod Tg is bent and mounted via a hinge on the vertical flange Av of the latch Lq. This joint is located generally at the same height as the joint At thus providing a quasi-vertical descent movement for said rod during its actuation. The rod Tg is slidably mounted through a ring of relatively small thickness capable of accepting a slight misalignment of said rod. The mechanism 300 further comprises a return means Mr designed to return the latch Lq to its retracted position. The return means Mr is constituted in this FIG. 5, a spring mounted on the upper part of the rod Tg, between the sliding ring and a stop ring integral with said rod.

The upper part of this rod is surmounted by a pusher adapted to be actuated by the foot. Two stops limit the L latch excursion between its two extreme service positions. They consist advantageously of two plates perpendicularly extending the vertical wing Av, at one of its corners, to bear one or the other on a sliding flank G2.

The mechanism 300 is active during the downward movement of the scale Ec between the two slides G, so that it stops the ladder as soon as its first bar meets said mechanism. To allow the descent of said ladder, the operator presses on the pedal Pl, which raises the latch Lq, leaving free the sliding movement of the scale Ec in the two slides G. The release of the pedal will then imply automatically blocking the first bar located above said latch during the descent of the ladder. On raising the scale, the mechanism 300 is passive, that is to say, it allows the upward movement thereof by retraction latch Lq. Each rising bar Br in the box 200 raises the sloping wing Ao protruding which then retracts by pivoting while compressing the spring. When the bar Br has passed over the latch, it automatically returns to its blocking position. To go down, to go up the ladder in the confined environment, the apparatus 100 maneuver of the invention can be equipped with a winch maneuvering. It is shown in Figs. 2 and 3, under the reference 420. It is fixed on a bracket 400 held in a support 430 fixed on the inner face of the intermediate wall 212 of the U-shaped plate 210 constituting the box 200. The bracket 400 consists of a first strand 422 which extends vertically upwards in the use position of the apparatus 100, extended by a second strand 424 which extends obliquely outwards and on which the winch 420 is mounted. The free end of the first strand 422 is held in the support 430. This first strand 422 preferably has a square section and the support 430 takes the form of a hollow tube also of square section, provided with a stop and adapted to receive and lock the stem according to four orientations offset by 90 °. This faculty allows a positioning of the winch 420 in a configuration that best suits the provision of access to the confined environment. The winch 420 comprises a crank for operating a drive mechanism for rotating a winding drum of a cable Cb. This cable runs on a pulley Po fixed at the level of the connection between the two strands 422 and 424.

The free end of the cable is fixed, via a hook Cr, to a bar Br of lower rank of said ladder. The use of the apparatus 100 for operating a scale Ec is as follows. The casing 200 is fixed by its intermediate wall 212, on a supporting structure, underlying access to the confined environment. The position of the flanges 3029560 9 230 can be adjusted to lower the ladder to the desired location in the confined environment, between the bar bars or to reduce the depth of the box 200 according to the configuration of the access window. To gain access to the confined environment, the operator releases the access hatch without raising the bar if it is installed. It fixes, if it is present, the bracket 400 provided with its winch on the support 430 by orienting it properly, then attaches the cable Cb to a bar Br of the scale Ec. He then engages the latter between the two slides G, until his lower rank bar comes into abutment on the latch Lq. It stretches the cable Cb by operating the winch crank 420, then raises the ladder slightly to disengage it from the latch Lq. He then presses on the pedal Pl, which raises the latch Lq. The operator can thus control the descent of the ladder by maneuvering the winch 420, until the foot of the ladder reaches the bottom of the confined environment. The operator can at this point raise the fall arrest bar. The operator descends into the confined environment using the ladder to perform the procedure for which he is responsible. When his work is finished, he leaves the confined environment using the ladder. He can then without fatigue make it back up using the winch 420. The intervention being completed, he leaves the confined environment by taking the ladder, the winch and his gallows, after having closed and padlocked the access hatch. If the ladder is in several elements, to facilitate its transport, to facilitate its descent or in case of reduced height under ceiling, the operator begins by lowering a first element between the two slides G until his bar lower comes to bear on the latch Lq, then he assembles the second element with the first. It proceeds in the same way for the following element (s). A safety rope intended may be attached to a rung of the ladder to secure the descent and ascent of the operator in the confined environment. It is strapped on a harness worn by the operator. A self-locking rope retractor, commonly referred to as a "fall-and-fall retractor" can be attached to a rung of the ladder to secure the descent and ascent of the operator in the confined environment. It is strapped on a shoulder belt that the operator wears. The gallows equipped with its winch are only used if the ladder is considered too heavy to be manually raised. The apparatus 100 of the invention reduces the accidental risks of handling the ladder in a confined environment. Its use is simple.

Claims (10)

CLAIMS1) Apparatus (100) for allowing the descent and the ascent of a ladder in a confined environment, comprising a box (200) for fixing the apparatus on a supporting structure, said box comprising two rails (G1, G2) turned facing each other and intended to allow the sliding of the two uprights (Mt) of a ladder (Ec), a locking means for each bar (Br) of said ladder, characterized in that the blocking means ( 300) comprises a latch (Lq) movable between a locking position of said bar where said latch is arranged between the two rails (G) and a retracted position where said latch is clear of the passage of the bars between the two rails, the latch being connected to a pedal (Pl). 2) Apparatus (100) according to claim 1, characterized in that the locking means (300) is provided with a return means (Mr) latch (Lq) to its locking position, in the absence of action on the pedal (Pl). 3) Apparatus (100) according to claim 2, characterized in that the latch (Lq) comprises a vertical flange (Av), in the laying position of the box (200), mounted in an articulated manner on a slide (G), extended perpendicularly by a wing (Ao) arranged obliquely upwardly and outwardly in the locking position of said latch, and which exceeds the vertical wing (Av), to form with the vertical wing (Av), a cradle in V on which can support a bar (Br) of a ladder, the oblique wing (Ao) used to raise the latch (Lq) to disengage under the effect of the raising of a bar (Br) of said ladder between the two slides (G). 4) Apparatus (100) according to any one of the preceding claims, characterized in that the box (200) has in section a U-shaped geometry defined by an intermediate wall (212) for fixing said apparatus (100), extended perpendicular to its two edges of two side walls (216) on which are retained the two rails (G1, G2). 5) Apparatus (100) according to claim 4, characterized in that the two rails (G) are respectively fixed on two flanges (230) mounted on the two side walls (216), the box being provided with means for adjusting the position of the two flanges (230) so as to be able to change the position of the two slides. 6) Apparatus (100) according to claim 4 or 5, characterized in that the pedal (P1) comprises a rod (Tg) slidably mounted in a substantially vertical direction in a bracket bracket (Pf) integral with one 3029560 11 side walls (216) or one of the flanges (230), the lower end of said rod being hingedly mounted on the vertical flange (Av) of the latch (Lq) to maneuver between its two extreme positions. 7) Apparatus (100) according to any one of the preceding claims, 5 characterized in that a bracket (400), equipped with a winch (420), is mounted on the box to go down or up a ladder (Ec ) between the two slides (G). 8) Apparatus (100) according to any one of the preceding claims, characterized in that it comprises a scale (Ec). 10 9) Apparatus (100) according to claim 8, characterized in that the scale (Ec) consists of at least two elements, an upper element (Es), a lower element (Ei), the two uprights (Mt) of one element being respectively provided with two sleeves (Mo) capable of being nested in the uprights (Mt) of the other element, the scale being provided with at least one retaining means (Ct) to assemble each other the two elements of the scale. 10) Apparatus (100) according to claim 8 or 9, characterized in that the sleeves (Mo) are provided with lateral lugs (Eg) sized to slide without mechanical play in the uprights (Mt).