EP0335311B1 - Hydraulic scaffold - Google Patents

Abstract

This scaffolding comprises a base, a pair of spaced posts on said base each formed of modular post sections, releasably secured one on top of the other by fasteners. Each post section is formed of a lattice frame with transversely-extending bars forming anchoring steps, equally spaced along the post. A work platform surrounds the posts and is guided therealong for up-and-down movement. A pair of anchoring hooks are pivoted at theri lower end to the platform and are engageable with the steps of the two posts to suspend the platform. A pair of hydraulic rams are pivoted also to the platform adjacent each post and upwardly-upstanding piston rods are provided with hooks to engage the steps of the post and raise or lower the platform. The hydraulic supply for the rams is mounted on the platform. The hook members are biased towards the posts, so that they automatically engage the steps. A single operator can operate the rams to raise and lower the work platform. The same operator can install the modular post sections as the platform is being raised and can dismantle when the platform is lowered. A swing stage is supsended from the work platform by flexible cables. The operator can climb down on the work stage to install bracing bars for interconnecting the posts as the platform is raised and to attach tie-rods to the posts and to an adjacent building wall to be covered with bricks or the like, which is carried by the platform.

Description

The invention relates to scaffolding and, more particularly, to a scaffolding arranged so as to be installed along a building wall for use by workers during the installation of a covering on this wall, by example a brick facing.

By document US-A-4,293,054 there is already known a scaffolding comprising a base; a pair of spaced posts, attached to, and projecting from the base, each post being formed of modular post sections; fastening means for detachably and successively fixing said sections of posts one above the other, said posts defining bearing means which are substantially equidistant; a work platform surrounding said posts and capable of being raised and lowered with respect to said posts; a pair of anchoring members pivotally carried by said platform adjacent to each post, and alternately and successively engaging with said posts to suspend said working platform from said posts at different levels; at least one member controlled by force, said platform being able to rise and descend by said members controlled by force; restraint means associated with said anchoring members for causing automatic engagement of said anchoring members with said posts when said platform is raised or lowered; the other anchoring member of said pairs alternately engaging said posts to suspend said platform when the latter is raised or lowered by the members controlled by force; said pole sections being arranged so that they can be fixed or removed by a single worker on said platform on or from the highest fixed pole sections when said platform is at the general level of said highest fixed pole sections.

In this known scaffolding, the platform is lifted along the posts by a motorized rack system. No means is provided for fixing the posts to each other and to the building wall so that this scaffolding can only reach a limited height.

Furthermore, document DE-A-2 342 630 relates to a scaffolding provided with a lifting member which can be a rack or a jack.

The main object of the present invention is to make a scaffold, having means allowing a worker working on the platform to install the modular sections of posts and fasteners for the posts and tie rods from the posts. towards the building wall to stabilize the posts as the platform is raised and to allow the installation of scaffolding at a sufficient distance from the building wall to clear balconies and others that can make protrusion from the wall of the building.

Another object of the present invention lies in new means for lifting and lowering the platform and its load along the posts.

For these purposes, according to the invention, the scaffolding comprising a base, a pair of spaced-apart posts fixed to and projecting from said base, each post being formed of modular post sections, fastening means for detachably fixing and successive said sections of posts one above the other, said posts defining substantially equidistant bearing means, a working platform supported by said posts and capable of being raised and lowered with respect to said posts, a pair of anchoring members, pivotally carried by said platform adjacent to each post, and alternately and successively engaging with said bearing means, for suspending said platform working from said posts at different levels, constraint means associated with said anchoring members, to cause automatic engagement of said anchoring members with said bearing means when said platform is raised or lowered, said post sections being arranged so that they can be fixed or removed by a single worker on said platform on or from the highest pole sections, when said platform is at the general level of said highest pole sections, is characterized by the fact that at least one anchoring member of said pair is a force-controlled member which can be extended and retracted along said posts relative to said working platform, for a stroke at least equal to the vertical spacing between the adjacent bearing means, said platform being able to rise and descend by said members being able to lengthen, that the other member of said pairs alternately engaging said bearing means, for suspending said platform when the latter is raised or lowered by the members capable of being extended by said pairs, and a flying bridge, of a length at least equal to the distance between the two said posts, is suspended by suspension cables under said platform in a position such that a worker can descend of the platform on the flying bridge and have access to the two posts so that they can be connected by spacers.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 is an end elevational view of the scaffolding in the elevated position next to a building wall to be covered with bricks.

Figure 2 is an end elevation view similar to that of Figure 1, but on an enlarged scale and with the working platform practically at ground level.

Figure 3 is a side elevational view of the scaffolding.

Figure 4 is a top plan view of the scaffolding.

Figure 5 is a vertical section through a post and through the working platform.

Figure 6 is a plan section taken along line 6-6 of Figure 5.

Figures 7 to 11 are vertical sections similar to that of Figure 5, but showing the various members for lifting and lowering the platform along the post and showing the successive positions taken by these members.

If we refer to Figures 1 to 3, we see a rigid base 20 consisting of a central beam 22 and two transverse beams of ends 24 from each end of which protrudes down a foot or adjustable leveling disc, 26. At the junction of the end beams with the central beam, four standing tubes 28 are fixed, arranged at the corners of a rectangle. Each group of four tubes 28 are arranged to support and fix a post 30. Each post consists of modular post sections, 32. Each post section consists of an open trellis frame having a rectangular section and comprising four angular members corner and elongated, 34, interconnected by inclined fasteners 36 and by transverse fasteners 37 along two opposite faces of each post and by transverse bars 38 along two other faces opposite of each post 30. When the post sections are interconnected one above the other, the transverse bars 38 are vertically equidistant and form anchor bearings. Preferably, the lower end of the corner members 34 of each post section comprises a projecting plate 39 which can engage in the upper end of the corner members 34 of the immediately lower post section, these plates being anchored in place by transverse pins 40 passing through orifices in the overlapping parts, as shown in FIG. 5. Each post section 32 has such a length and width that it can be easily handled by a single worker, by means of 'a manual winch if necessary, on a work platform 42 suspended from the two posts. Therefore, the many post sections 32 can be carried by the working platform 42 and successively installed one above the other as the platform is being lifted and dismantled as and as the platform is lowered.

Referring to Figures 2 to 4, the working platform 42 is generally rectangular in shape and comprises a main frame 44 directly supporting a floor 46, the frame 44 being reinforced below by a bottom frame 48. As illustrated in Figure 4, the working platform 42 has two openings 50 spaced along the central line of the working platform for the passage of the two posts 30. The frame 44 and the bottom frame 48 are made of two tubular metal members in which platform extension sections, 52, can be removably installed, at various levels, as shown in FIG. 2, and also in FIGS. 2 and 3 in the form of supports for support the floor 54 near a building wall 56 and which can be arranged to follow the outline of the building wall, as shown in plan section in FIG. 4, so as to allow a worker A to stand stand near the building wall and install a covering, for example bricks referenced B, using mortar C.

As illustrated in Figure 1, the scaffolding can be installed sufficiently spaced from a building wall 56, so as to completely clear any protruding obstruction such as balconies D and the like. The platform extensions are temporarily removed to clear each balcony as the brick laying work progresses up the wall.

As shown in Figures 2 to 4, a balustrade or ramp 58 is removably installed on three sides of the platform as a safety measure. Part of this balustrade can be used as an opening door, as shown at 60 in Figures 3 and 4, to allow easier loading of the working platform when it is substantially at ground level. If desired, platform extensions can be installed at both ends of the main work platform, 42, to increase the width of the wall section accessible to workers.

A flying bridge 62 is suspended under the working platform 42 by cables 64. Guard railings 66 are also connected to the cables 64. Also, vertical stabilization rods, 68, are fixed to the flying bridge 62 and carry a stop at their upper end. They are guided by sliding in sleeves 70 fixed to the working platform 42. The guide rods 68 stabilize the flywheel 62 laterally and longitudinally, and firmly stop the flying bridge at the desired level under the platform 42.

This arrangement allows the flying bridge to rest on the base 20 immediately under the working platform 42 when the latter is in the fully lowered position, with its bottom frame 48 resting on the base 20 so that the platform completely lowered and the base can occupy a minimum of height when not used to facilitate their transport from one construction site to another.

The flying bridge 62 carries posts 72 (FIG. 2) provided with stirrups 74 to support elongated spacers, not shown, to be installed by the worker, who has come down from the working platform on the flying bridge 62, so to attach the two posts to each other. These attachment bars are successively attached at the required height intervals, while the platform is being lifted, and are similarly detached from the posts when the platform is lowered, and the post sections successively undone. At the same time, as shown in Figure 1, the attachment rods 76 supported by the hooks 64, are installed by the worker to attach the two posts to the building wall 56 while the platform is raised, so to stabilize the posts in the direction towards and outside the building wall. When the platform is lowered, the tie rods 76 are removed, again using the flybridge to access it. Eyelets 78 have been previously fixed to the wall 56 and a hook 80 fixed to one end of the tie rods 76 serves to engage the eyelets 78. The tie rods 76 are fixed to the posts 30 by adjustable connectors, 81.

As shown in Figures 5 and 6, the working platform 42 is guided along the post 30 by two sets of rimmed guide rollers, 82, engaging the angular members 34 at the four corners of each post, one set at the working platform 42, and the other set of rim rollers 82 being carried by the bottom frame 48 vertically below the first set of rollers, so as to better stabilize the platform, transversely to the posts 30.

Figure 7 shows the means for suspending the platform from each pole and for raising or lowering the platform along the poles. An anchor arm 84 is disposed on one side of each post and is pivoted at 86 to the ears 88 fixed to the frame 44 of the working platform. The upper end of each arm 44 carries a hook 90, opening downwards, engaged in a removable manner with any of the transverse bars 38 of the pole sections 32 to suspend the platform there. The lower end of each arm 84 comprises a lateral arm 92 to which a tension spring 94 is attached, the other end of which is attached to a post 96 fixed to the platform 42. The spring 94 constantly forces the arm 84 towards the post 30. The lower end of a guide bar 98 inclined outwards and upwards is fixed to the hook 90. When the hook 90 engages a transverse bar 38, the guide bar 98 is at least at the level of the bar higher next 38 so as to slide on the latter when the platform is raised along the post, and allow the hook to hang on this last bar 38 under the stress of the spring.

As a safety measure, a second anchoring system consisting of an arm 84 ', a pivot 86', ears 88 ', a hook 90', a lateral arm 92 ', a tension spring 94 'and a guide bar 98' is installed on the bottom frame 48 vertically below the first anchoring system, so that the two hooks 90, 90 ′ can engage different transverse bars at the same time, as shown in FIG. 7. This FIG. 7 also shows manual actuation means for pivoting at distance the lower arms 84 ′ outwards, so as to release the transverse notches 38 from the two posts during the lowering of the platform. These means comprise a side arm 100 fixed to the lower arm 84 'and connected by a connecting rod 102 to an actuating lever 104 pivoted to the working platform 42 in a position accessible to the worker on the platform, to release the lower hook. The upper hook can be released by pulling out the guide bar 98 when releasing the notch 38 as shown in FIG. 9.

As illustrated in FIG. 7, when the upper hook 90 engages a transverse bar 38, the lower hook 90 'barely releases the corresponding transverse bar, the entire load of the platform being supported by the upper hook, so that the lower hook will be in a condition to support the platform in the event that the upper hook should yield or in the case where its corresponding crossbar should yield.

The other anchoring member of the pair is shown at 106 in FIG. 7, it is actuated by force; it can lengthen and retract longitudinally, so as to raise or lower the platform in relation to the posts.

The extendable member 106 comprises a double-action hydraulic cylinder 108 pivoted at its lower end 110 to the bottom frame 48 of the work platform and extending upwards thereof through the opening 50 of the work platform. job. The jack 108 has a piston rod 112 extending towards the high from the platform and the upper end of which is pivoted at 114 to the rigid arm 116, the upper end of which is fixed to a hook opening downwards, 118, similar to the hook 90, and which is also provided a guide bar inclined outwards and upwards, 120, similar to guide bar 98 and for the same purpose.

To constantly orient the hook 118 towards the transverse bars 38 of the post, and to guide the pivoting movement of the arm 116 towards and outside the post despite a possible rotation of the piston rod 112 in the body of the jack 108, a support 122 is fixed to the upper end of the piston rod 112, said support carrying the pivot 114 and also a guide rod 124 which extends downwards, parallel to the piston rod 112, and which is guided in a sleeve 126 fixed to the upper end of the cylinder of the jack 108.

As shown in FIG. 7, the pivot 110 of the lower end of the jack 108 is sufficiently spaced from the post 130 so that the center of gravity of the jack and the hook system are always between the pivot 110 and the post. This therefore constitutes a means of constantly and automatically constraining the hook 118 against the post, so as to cause automatic engagement of the hook 118 with a transverse bar 38 when the platform is being lowered or raised.

As shown in Figure 7, the stroke of the jack 108 is at least slightly more than the vertical spacing between two adjacent notch bars 38 of the post 30; but, in practice, the stroke is a little more than the distance between three notch bars, so as to raise or lower the platform by two notches for a single stroke of the jack 108, thereby accelerating the lowering or lifting procedure.

In FIG. 7, the hook 90 only suspends the working platform. The hook 118 is raised by the piston rod 112 from its position in dotted lines to a position slightly above the second highest notch bar 38, then after slightly lowered to engage the last mentioned notch. Then, following the retraction of the piston rod 112, as shown in FIG. 8, the whole platform is raised; the hook 90 releases the next two higher notches (Figures 8-9) until the piston rod 112 is fully retracted, at which position the hook 90 is slightly higher and releases the adjacent notch bar. Then, the piston rod 112 is slightly extended to substantially lower the platform and force the hook 90 to fully engage the adjacent catch bar 38, as shown in FIG. 10. The platform is suspended securely and the cycle is repeated .

The lowering of the platform is also carried out two notches at a time, as shown in FIG. 11. In order to prevent the upper hook 90 from catching on an intermediate notch 38 ′ during the descent, we proceed as follows : after having slightly raised the platform 42 so that the hook 90 releases the notch 38 '', and after having pulled on the guide bar 98, a plate 128 is temporarily suspended from the notches 38 'and 38''so that the hook 90 engages only the 38 '' notch. During this lowering step, the lever 104 is actuated to allow the hook 90 'to be released. Of course, the two hooks 90 'can be interconnected from one post to the other, so that a single lever 104 can operate the two lower hooks.

The arm 116 of the jack 108 is pivoted at 114 to the support 122 to prevent any stress on the piston rod 112 during its movement in the body of the jack 108. As shown in FIG. 10, when the jack does not work, the arm 116 remains simply pressed on the post 30 and when the arm is under tension, the piston rod automatically aligns with said arm. Preferably, a spiral spring is arranged at the pivot 114 in order to constantly constrain the arm 116 towards the post 30.

The two jacks 108 are connected by a hydraulic circuit, including the tube 130 (Figure 10), to a hydraulic pump (not shown) located in a box 132 (Figure 3) installed on the working platform 42, in the vicinity of a pole 30. The box 132 also contains an internal combustion engine for driving the hydraulic pump. The hydraulic circuit is controlled by hydraulic valves (not shown) actuated by means of control levers 134 by the worker standing on the platform.

A single worker can handle the entire lifting and lowering procedure of the platform, including the installation of pole sections 32, as the platform is raised; their removal as the platform is lowered and including the descent on the flying bridge 62 and the installation or removal of the spacers connecting the two posts and tie rods 76 connecting each post to the adjacent wall 56 .

The platform is strong enough and the hydraulic system is powerful enough to lift a platform, including the required number of workers, the total load of bricks and mortar sufficient for laying bricks for a multi-storey building on a width equivalent to the length of the work platform and even on an extension thereof. If additional building materials are required, a winch system can be installed on the work platform to lift them. The scaffolding is quickly installed and dismantled, and when completely dismantled, occupies a reduced space to facilitate its transport to another construction site.

A set of wheels can be installed at 136 (Figure 3) at the bottom frame and a towing device can be installed at 138 at the opposite end, so that the scaffolding can be easily pulled by a tractor-trailer such as a semi-trailer, the platform being completely lowered to the base 20 and the latter being blocked under the platform.

Claims (6)

1. Scaffolding comprising a base (20), a pair of spaced posts (30), secured to and projecting from said base (20), each post being formed of modular post sections (32), fastener means (39,40) to releasably and successively secure said post sections on top of one another, said posts defining substantially equally-spaced step means (38), a work platform (42) supported by said posts (30) and adapted to be raised and lowered relative to said posts, a pair of anchoring members (84, 116) pivotally carried by said platform adjacent each post, and alternately and successively engageable with said step means, to suspend said work platform from said posts at different levels ; biasing means associated with said anchoring members, to cause automatic engagement of said anchoring members with said step means as said platform is raised or lowered, said post sections (32) being arranged to be secured or removed by a single workman standing over said platform onto or from the topmost secured post sections, when said platform is at general level of said topmost secured post sections, characterized in that at least one anchoring member (116) of said pair is a power-actuated member (106) which is extendible and retractable along said posts relative to said work platform, through a stroke at least equal to the vertical spacing between adjacent step means, said platform (42) being raisable and lowerable by said extendible members ; that the other member (84) of said pairs alternatively engages said step means, to suspend said platform as the latter is raised or lowered by the extendible members of said pairs ; and that a hanging stage (62), of a length at least equal to the distance between the two said posts ; is suspended by suspension cables (64) beneath said platform (42) in such a position that a worker may descend from the platform on the hanging stage and gain access to the two posts so as to be able to interconnect them by cross-braces.
2. Scaffolding according to claim 1,
   characterized in that said work platform (42) surrounds each post (30) and in that it comprises tie-rods (76) provided with a hook (80) at one end and a coupling (81) at the other end and used to secure said posts to a building wall along which said posts are erected, said hanging stage comprising stirrups (74) to support said tie-rods (76) in their storage condition and said tie-rods being attachable to the posts and to the wall by a worker on the hanging stage.
3. Scaffolding according to claim 2,
   characterized in that it comprises guiding means (68,70) to prevent said hanging stage (62) from swinging at the end of its suspension cables (64), while enabling the bringing together of said hanging stage toward the bottom of said platform in a transportable condition of the scaffolding whereby said platform stands onto said base (20).
4. Scaffolding according to one of claims 1 or 2,
   characterized in that said power-actuated member (106) comprises a hydraulic ram (108) whose bottom end is pivoted (110) to said platform and whose top end of the piston rod (112) is provided with a hook (116, 118) which may hook itself successively to the anchoring step (38) of said posts (30), a guiding arm (120) being secured to the upper end of said hook (116, 118) and upwardly outwardly extending from said post so as to project beyond the next upper anchoring step when the hook is hooked to an anchoring step (38), the assembly of said ram and of said hook being located along one side of said post, the center of gravity of said assembly being located between said post and the pivotal joint of said ram to said platform, thus constituting biasing means causing the automatic engagement of said hook with one or the other of said anchoring steps, said guiding bar sliding against said anchoring steps so as to guide said hook in its upwardly hooking motion.
5. Scaffolding according to claim 4,
   characterized in that said anchoring means comprises a hook (84, 90) located along each post and pivoted at its lower end (86) to the work platform (42) and also provided with a guiding bar (98) which extends upwardly and outwardly relative to said post, said hook (84, 90) being used to suspend said platform to said post when said hydraulic ram is not in action and biasing means biasing said hook (84, 90) to pivot toward said post so as to enable said guiding bar (98) to slide along said anchoring steps (38).
6. Scaffolding according to claim 5,
   characterized in that said hook (116, 118) is pivoted at its bottom end to the upper end of said piston rod (112) and in that it further comprises a guiding rod (124) sliding within a sleeve (126) which is secured to the body of said ram (108), the top end of said guiding rod (124) being integral to the top end of said piston rod (112) so as to prevent rotation of said piston rod and thus of said hook (116, 118), along the longitudinal axis of said hydraulic ram (108).

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