Lifting boom tower crane provided with an adjustable wind load system

Abstract

Tower crane comprising a tower on which is pivotally mounted a boom (1) movable in elevation and in lowering between a lowered position and a raised position, said crane being configurable between a service configuration in which the boom is controlled in rotation and a safety configuration in which the boom is in a raised position and is released in rotation on the tower to be able to orient itself in the direction of the wind, where a wind-catching system (2) is mounted on the boom and adjustable between a retracted conformation used in the service configuration to provide a reduced surface exposed to the wind, and a deployed conformation used in the safety configuration to provide an extended surface exposed to the wind, where this wind-catching system is configured to pass from the retracted conformation to the deployed conformation under the effect of its own weight alone when the boom is raised.

Description

[0001] The invention relates to a luffing jib tower crane equipped with an adjustable wind resistance system. Furthermore, the present invention relates to a method for securing a luffing jib tower crane.

[0002] The present invention applies to the field of tower cranes comprising a luffing jib, and can be applied to several crane structures, for example to structures composed of lattices and frames.

[0003] Conventionally, a tower crane comprises a tower on which a boom is pivotally mounted along an axis of orientation, generally vertical, this boom being movable in elevation and lowering between a lowered position and a raised position, for example by means of a hydraulic system or a cable system.

[0004] Furthermore, such a tower crane is configurable between: a service configuration in which the boom is driven in rotation on the tower along the orientation axis (also called orientation steering) to move a load by means of a lifting system carried by the boom, and a safety configuration in which the boom is in a raised position and is released in rotation on the tower along the orientation axis, to be able to orient itself in the direction of the wind, the boom is then free to rotate around the orientation axis and it is conventional to say that the boom is put into a weather vane.

[0005] Indeed, for safety reasons, and particularly in the event of strong winds, it is recommended, or even mandatory, to secure the tower crane (also called wind vaning the boom), by disengaging the boom (in other words by freeing the boom from rotating on the tower, for example by releasing the slewing brakes) so that it is free to rotate and automatically orient itself in the direction of the wind and thus allow the crane to be left without human supervision.

[0006] In the case of a luffing jib crane, the wind vane is carried out with the boom in the raised configuration to minimize the boom's turning radius and thus prevent the boom, in wind vane, from flying over areas close to the site, such as traffic lanes, buildings, etc.

[0007] When the crane is in the safety configuration, the balance between the boom windage must be favorable compared to the tailwind (at the counter-jib) so that the boom orients itself naturally in the wind. However, on a luffing jib crane, with the jib raised, the slewing torque resulting from the wind force on the boom is reduced and weathervaning (or alignment in the direction of the wind) is delayed or even difficult.

[0008] In order to ensure this weathervaning, it is known, in particular from document EP3064465, which discloses the preamble of claim 1, to provide on the boom a wind-catching system (also called a sail system) provided with one or more sails which offer an adjustable surface exposed to the wind, and in particular a surface exposed to the wind which is increased when the boom is in the safety configuration, so as to increase the wind pressure on the boom of the crane and thus allow it to better orient itself in the direction of the wind. This document EP3064465 proposes to use a drive mechanism which acts on the sail(s) to deploy them (and thus increase their surface exposed to the wind) or retract them (and thus reduce their surface exposed to the wind).

[0009] However, the use of such a drive mechanism has the disadvantage of complicating the installation of such a windage system, and thus increasing the installation cost, sometimes prohibitively when it is required to install a windage system on an existing crane, or to redesign a crane to integrate this adjustable windage surface functionality. Furthermore, the presence of an additional drive mechanism in a boom makes the latter heavier, and thus penalizes the load curve of the boom and therefore reduces the performance of the crane.

[0010] The present invention aims in particular to resolve all or part of the aforementioned drawbacks, by proposing a wind-catching system which is of lightweight, simple and inexpensive design, to facilitate installation on existing cranes or to easily design new cranes with a wind-catching system.

[0011] Another aim of the invention is to propose a wind-catching system which, in particular due to its lightness, will make it possible to deploy a large surface exposed to the wind in the safety configuration, which makes it possible to increase the lifting angle of the boom (in other words to bring it closer to the vertical), and therefore to reduce the turning radius of the boom in this safety configuration, while allowing effective alignment in the direction of the wind.

[0012] To this end, the invention provides a tower crane comprising a tower on which a boom is pivotally mounted along an axis of orientation, this boom being movable in elevation and in lowering between a lowered position and a raised position, and the tower crane being configurable between a service configuration in which the boom is controlled in rotation on the tower along the axis of orientation, and a safety configuration in which the boom is in a raised position and is released in rotation on the tower along the axis of orientation to be able to orient itself in the direction of the wind, where the tower crane comprises at least one wind-catching system mounted on the boom and adjustable between a retracted conformation used in the service configuration and in which the wind-catching system offers a reduced surface exposed to the wind,and a deployed conformation used in the safety configuration and in which the windage system provides an extended windage surface which is greater than the reduced windage surface, this tower crane being remarkable in that the windage system is configured to pass from the retracted conformation to the deployed conformation under the effect of its own weight alone when the boom is raised to pass from the lowered position to the raised position.,

[0013] Thus, the invention proposes to do without a drive mechanism to deploy the wind-catching system, and thus to increase the surface exposed to the wind, by exploiting the own weight of the wind-catching system, which will allow, when raising the boom, a deployment by gravity. In other words, when the boom is raised, the boom changes its inclination relative to the vertical, and thus the wind-catching system will naturally change its conformation, under the effect of gravity which naturally applies a vertical force on the wind-catching system.

[0014] Such a wind-resistance system thus allows for gravity-based "control" that avoids any addition of dead weight in the boom and therefore does not penalize the crane's performance. This wind-resistance system also naturally allows for a maximum surface area exposed to the wind when the crane is in safety configuration, and a minimum surface area exposed to the wind when the crane is in service configuration and requires slewing performance.

[0015] It should be noted that, just as naturally, the wind-catching system is designed to move from the deployed to the retracted configuration under the effect of its own weight alone when the boom is lowered to move from the raised position to the lowered position.

[0016] In a particular embodiment, the wind-catching system comprises at least two sail elements, including at least one free-moving sail element, where: in the retracted conformation, the sail elements are at least partially superimposed on each other when the boom is in the lowered position in order to provide the reduced wind-exposed surface; in the deployed conformation, the sail elements are spaced apart from each other when the boom is in the raised position in order to provide the extended wind-exposed surface; and where the free-moving wing element(s) move freely under their own weight when the boom is raised from the lowered position to the raised position.

[0017] Thus, the free-moving wing element(s) will in some way "fall" under their own weight when the boom is raised, while of course being held on the boom, and it is this movement which causes it(them) to change shape. It should be noted that, just as naturally, the free-moving wing element(s) move freely under the effect of their own weight alone when the boom is lowered to move from the raised position to the lowered position.

[0018] According to one characteristic, the free-moving wing element(s) are mobile at least in rotation.

[0019] Thus, the free-moving wing element(s) will at least pivot, under their own weight, when the boom is raised.

[0020] According to one possibility, the free-moving wing element(s) are mobile in rotation along the same axis of rotation.

[0021] According to another characteristic, the free-moving wing element(s) are mobile at least in sliding.

[0022] Thus, the free-moving wing element(s) will at least slide, under their own weight, when the boom is raised.

[0023] Alternatively, the wind-catching system includes at least one stop associated with a free-moving sail element to stop said free-moving sail element in its mobility when the boom is raised from the lowered position to the raised position.

[0024] The presence of the stop advantageously makes it possible to stop the associated free sail element in the "right place" to have a maximum surface exposed to the wind, the stop providing a sort of control over the amplitude of deployment or the final positioning of the free sail element.

[0025] Alternatively, the wind-catching system comprises a static wing element and one or more freely movable wing elements, the one or more freely movable wing elements being at least partially superimposed in front of or behind the static wing element in the retracted configuration.

[0026] In a particular embodiment, the sail elements of the wind-catching system are made at least partially from one of the materials chosen from: a metallic material, such as for example aluminum, a plastic material, a textile material, a composite material.

[0027] According to one possibility, the sail elements of the wind-catching system are flat and parallel to each other in the deployed conformation.

[0028] The invention also relates to a method for securing a tower crane according to the invention, comprising: a step of releasing the boom rotating on the tower along the orientation axis, to be able to orient itself in the direction of the wind; a step of raising the boom to move from the lowered position in which the wind-catching system is in its retracted configuration to the raised position in which the wind-catching system is in its deployed configuration; where, during the raising of the boom, the wind-catching system passes from the retracted conformation to the deployed conformation under the effect of its own weight alone.

[0029] In the embodiment with wing elements, during the raising of the boom, the free-moving wing element(s) move freely under the effect of their own weight alone to increase the surface area exposed to the wind of the wind-catching system.

[0030] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of non-limiting examples of implementation, made with reference to the appended figures in which: [ Fig 1 ] is a schematic side and partial view of a boom of a tower crane according to the invention, the boom being in the lowered position and supporting a first wind-catching system according to the invention and which is in the retracted position; [ Fig 2 ] is a schematic partial side view of the arrow of the Figure 1 , the boom being in the raised position and the first wind-catching system being in the deployed position; [ Fig 3 ] is a schematic side and partial view of a boom of a tower crane according to the invention, the boom being in the lowered position and supporting a second wind-catching system according to the invention and which is in the retracted position; [ Fig 4 ] is a schematic partial side view of the arrow of the Figure 3 , the boom being in the raised position and the second wind-catching system being in the deployed position; [ Fig 5 ] is a schematic side and partial view of a boom of a tower crane according to the invention, the boom being in the lowered position and supporting a third wind-catching system according to the invention and which is in the retracted position; [ Fig 6 ] is a schematic partial side view of the arrow of the Figure 5 , the boom being in the raised position and the third wind-catching system being in the deployed position; [ Fig 7 ] is a schematic side and partial view of a boom of a tower crane according to the invention, the boom being in the lowered position and supporting a fourth wind-catching system according to the invention and which is in the retracted position; and [ Fig 8 ] is a schematic partial side view of the arrow of the Figure 7 , the boom being in the raised position and the fourth wind catch system being in the deployed position.

[0031] A tower crane according to the invention comprises: a tower (also called a mast), extending vertically, anchored or movable on the ground; and a rotating part, surmounting the tower, which is pivotally mounted on the top of the tower according to an orientation axis, which corresponds to a vertical axis parallel to the vertical direction Z illustrated in the Figures.

[0032] This rotating part mainly includes: a rotating pivot forming a slewing device generally provided with slewing brakes, this rotating pivot being mounted on the top of the tower, and it generally supports a pilot cabin; a counter-jib on which a counterweight is mounted, which extends substantially horizontally towards the rear from the rotating pivot; and a boom 1 of the luffing jib type, which extends substantially towards the front, from the rotating pivot, along a longitudinal axis 10.

[0033] The rotating pivot is rotatable around the orientation axis, and thus, the boom 1 is pivotally mounted on the tower along the orientation axis.

[0034] The arrow 1 may be formed by a lattice structure, for example of triangular section. The arrow 1 has a proximal portion mounted on the rotating pivot, this proximal portion forming the foot of the arrow 1. The arrow 1 also has a free distal portion 11 which forms the tip of the arrow 1.

[0035] The proximal portion is furthermore articulated, around a horizontal pivot axis, on the rotating pivot, so that the boom 1 can pivot upwards or downwards along this horizontal pivot axis, and thus this boom 1 is a so-called lifting boom in the sense that it can be moved in elevation and in lowering between: a lowered position (visible on the Figures 1 , 3 , 5 And 7) in which the arrow 1 extends substantially horizontally, with the longitudinal axis 10 which is substantially parallel to a horizontal direction X; and a raised position (visible on the Figures 2 , 4 , 6 And 8 ) in which the arrow 1 extends obliquely, with the longitudinal axis 10 which is inclined relative to the horizontal direction X at an angle at least greater than 30 or 45 degrees, or even at least greater than 60 degrees, the distal portion 11 having risen compared to the lowered position.

[0036] The tower crane is also configurable between: a service configuration in which the boom 1 is driven in rotation on the tower along the orientation axis, conventionally by means of a dedicated orientation motor to rotate the rotating part; and a safety configuration in which the boom 1 is in the raised position and is released in rotation on the tower along the orientation axis to be able to orient itself in the direction of the wind, for example after disengaging the orientation brakes provided on the rotating pivot.

[0037] According to the invention, the tower crane further comprises at least one wind-catching system 2, 3, 4, 5 which is mounted on the boom 1 and which is adjustable between: a retracted conformation used in the service configuration and in which the wind intake system 2, 3, 4, 5 (visible on the Figures 1 , 3 , 5 And 7) offers a reduced surface exposed to the wind, and a deployed conformation (visible on the Figures 2 , 4 , 6 And 8 ) used in the safety configuration (i.e. when the boom 1 is in the raised position) and in which the wind-catching system 2, 3, 4, 5 provides an extended wind-exposed surface which is greater than the reduced wind-exposed surface.

[0038] Four examples of the implementation of a wind-catching system 2, 3, 4, 5 are illustrated in the Figures 1 à 8 , with a first wind catch system 2 on the Figures 1 et 2 , a second wind catch system 3 on the Figures 3 et 4 , a third wind catch system 4 on the Figures 5 et 6 and a fourth wind-catching system 5 on the Figures 7 et 8 .

[0039] Generally, the wind intake system 2, 3, 4, 5 is designed for: to move from the retracted conformation to the deployed conformation under the effect of its own weight alone (in other words under the effect of gravity) when the boom 1 is raised to move from the lowered position to the raised position, and vice versa to move from the deployed conformation to the retracted conformation under the effect of its own weight alone (in other words under the effect of gravity) when the boom 1 is lowered to move from the raised position to the lowered position.

[0040] In the four illustrated embodiments, the wind-catching system 2, 3, 4, 5 comprises at least two sail elements 20, 21, 30, 31, 40, 41, 50, 51, including one or more free-moving sail elements 20, 21, 31, 41, 51, where: in the retracted configuration, the sail elements 20, 21, 30, 31, 40, 41, 50, 51 are at least partially superimposed on each other when the boom 1 is in the lowered position in order to provide the reduced surface exposed to the wind; in the deployed configuration, the sail elements 20, 21, 30, 31, 40, 41, 50, 51 are spaced apart from each other when the boom 1 is in the raised position in order to provide the extended surface exposed to the wind.

[0041] More precisely, the free-moving wing element(s) 20, 21, 31, 41, 51 move freely under the effect of their own weight alone (in other words under the effect of gravity) when the boom 1 is raised to move from the lowered position to the raised position (and vice versa to move from the raised position to the lowered position).

[0042] It is advantageous to provide, for each free-moving wing element 20, 21, 31, 41, 51: a first stop for stopping this free-moving wing element in its mobility, when the boom 1 is raised, so as to stop it in an optimal deployed position to provide a surface exposed to the wind which is maximized, once the boom 1 is in the raised position; and a second stop for stopping this free-moving wing element in its mobility, when the boom 1 is lowered, so as to stop it in an optimal retracted position to provide a surface exposed to the wind which is minimized (by overlap between the wing elements), once the boom 1 is in the lowered position.In the first wind-catching system 2, the sail elements 20, 21 are in the form of flexible bellows, for example made of textile material, which are mounted on rigid frames 22 which pivot on the boom 1 along the same transverse pivot axis 23 which is both orthogonal to the vertical direction Z and to the longitudinal axis 10; this transverse pivot axis 23 being horizontal, whatever the position of the boom 1. The sail elements 20, 21 of this first wind-catching system 2 are all free to move.

[0043] In the retracted configuration, the wing elements 20, 21 are superimposed and folded over each other. When the boom 1 is raised, the rigid frames 22 of the wing elements 20, 21 pivot (as shown diagrammatically by the arrow P2) around the transverse pivot axis 23 (under the effect of their weight) and thus the wing elements 20, 21 deploy, providing an increase in the surface area exposed to the wind (in the manner of a fan).

[0044] In the second wind-catching system 3, the sail elements 30, 31 are in the form of wind plates, for example made of rigid metallic, composite or plastic material or of flexible material mounted on a rigid frame, and comprise: one or more freely movable wing elements 31 which are pivotally mounted on the boom 1 along the same transverse pivot axis 33 which is both orthogonal to the vertical direction Z and to the longitudinal axis 10, this transverse pivot axis 23 being horizontal, whatever the position of the boom 1; a static wing element 30, which remains static and does not pivot during the raising of the boom 1.

[0045] In the illustrated example, there are two free-moving wing elements 31. In the retracted configuration, the wing elements 30, 31 are superimposed on each other. When the boom 1 is raised, the free-moving wing elements 31 pivot (as shown diagrammatically by the arrow P3) around the transverse pivot axis 33 (under the effect of their weight) and thus the free-moving wing elements 31 deploy and move away from the static wing element 30, providing an increase in the surface area exposed to the wind.

[0046] In the third wind-catching system 4, the sail elements 40, 41 are in the form of wind plates, for example made of rigid metallic, composite or plastic material or of flexible material mounted on a rigid frame, and comprise: one or more free-moving wing elements 41 which are mounted to slide on the boom 1 along the longitudinal axis 10; a static wing element 40, which remains static and does not slide during the raising of the boom 1.

[0047] In the illustrated example, the free-moving wing element(s) 41 are one in number. In the retracted configuration, the wing elements 40, 41 are superimposed on one another. When the boom 1 is raised, the free-moving wing element(s) 31 slide (as shown diagrammatically by the arrow C4) along the longitudinal axis 10 (under the effect of their weight) and thus the free-moving wing element(s) 41 deploy and move away from the static wing element 40, providing an increase in the surface area exposed to the wind (like a drawer opening). In the fourth wind-catching system 5, the wing elements 50, 51 are in the form of wind plates, for example made of rigid metal, composite or plastic material or of flexible material mounted on a rigid frame, and comprise: one or more freely movable wing elements 51 which are pivotally mounted on the boom 1 along the same transverse pivot axis 53 which is both orthogonal to the vertical direction Z and to the longitudinal axis 10, this transverse pivot axis 53 being horizontal, whatever the position of the boom 1; a static wing element 50, which remains static and does not pivot during the raising of the boom 1, where this static wing element 50 is in the form of a disc centered on the transverse pivot axis 53 and provided with several windows 52.

[0048] In the retracted conformation, the wing elements 50, 51 are superimposed on each other so that the freely movable wing elements 51 release the windows 52. When the boom 1 is raised, the freely movable wing elements 51 pivot (as shown diagrammatically by the arrow P5) around the transverse pivot axis 53 (under the effect of their weight) and thus the freely movable wing elements 51 deploy and move away from the static wing element 50 in order to occupy or cover the windows 52, providing an increase in the surface area exposed to the wind (in the manner of an air vent).

[0049] In the example of the Figures 1 et 2 , the tower crane includes several wind-catching systems 2, which can be connected by a connecting bar 6 for parallel and synchronized movements, both in extension and retraction.

[0050] It should also be noted that, given the simplicity of these wind-catching systems 2, 3, 4, 5, which do not use any actuator, it is easy to install such wind-catching systems 2, 3, 4, 5 either as original equipment (in other words during the manufacture of the tower crane), or during an upgrade or improvement of an existing tower crane.

Claims

1. A tower crane comprising a tower on which a boom (1) is pivotally mounted around an orientation axis, said boom (1) being displaceable in elevation and in lowering between a lowered position and a raised position, said tower crane being configurable between a service configuration in which the boom (1) is controlled in rotation on the tower around the orientation axis, and a safety configuration in which the boom (1) is in a raised position and is released in rotation on the tower around the orientation axis in order to be able to be oriented in the direction of the wind, said tower crane comprising at least one wind load system (2; 3; 4; 5) mounted on the boom (1) and adjustable between a retracted configuration used in the service configuration and in which the wind load system (2; 3; 4; 5) offers a reduced surface exposed to the wind, and a deployed configuration used in the safety configuration and in which the wind load system (2; 3; 4; 5) offers an extended surface exposed to the wind which is greater than the reduced surface exposed to the wind, said tower crane being characterized in that the wind load system (2; 3; 4; 5) is designed to move from retracted configuration towards the deployed configuration under the effect of its own weight alone when the boom (1) is raised to move from the lowered position to the raised position.

2. The tower crane according to claim 1, wherein the wind load system (2; 3; 4; 5) comprises at least two wing elements (20, 21; 30, 31; 40, 41; 50, 51), whose at least one freely movable wing element (20, 21; 31; 41; 51), where: - in the retracted configuration, the wing elements (20, 21; 30, 31; 40, 41; 50, 51) are at least partially superimposed on each other when the boom (1) is in the lowered position in order to provide reduced surface exposed to the wind; - in the deployed configuration, the wing elements (20, 21; 30, 31; 40, 41; 50, 51) are spaced apart when the boom (1) is in the raised position in order to provide the extended surface exposed to the wind; and wherein the free movable wing element(s) (20, 21; 31; 41; 51) are freely displaced under the effect of their own weight alone when the boom (1) is raised to move from the lowered position to the raised position.

3. The tower crane according to claim 2, wherein the freely movable wing element(s) (20, 21; 31; 51) are movable at least in rotation.

4. The tower crane according to claim 3, wherein the freely movable wing element(s) (20, 21; 31; 51) are movable in rotation about a same axis of rotation (23; 33; 53).

5. The tower crane according to any one of claims 2 to 4, wherein the freely movable wing element(s) (41) are movable at least in sliding.

6. The tower crane according to any one of claims 2 to 5, in wherein the wind load system (2; 3; 4; 5) comprises at least one stop associated with a freely movable wing element (20, 21; 31; 41; 51) to stop said freely movable wing element (20, 21; 31; 41; 51) in its mobility when the boom (1) is raised to move from the lowered position to the raised position.

7. The tower crane according to any one of claims 2 to 6, wherein the wind load system (3; 4; 5) comprises a static wing element (30; 40; 50) and one or more freely movable wing elements (31; 41; 51), the one or more freely movable wing elements (31; 41; 51) being superimposed at least partially in front of or behind the static wing element (30; 40; 50) in the retracted configuration.

8. The tower crane according to any one of claims 2 to 7, wherein the wing elements (20, 21; 30, 31; 40, 41; 50, 51) of the wind load system (2; 3; 4; 5) are made at least partially in one of the materials selected from: a metallic material, such as for example aluminum, a plastic material, a textile material, a composite material.

9. The tower crane according to any one of claims 2 to 8, wherein the wing elements (20, 21; 30, 31; 40, 41; 50, 51) of the wind load system (2; 3; 4; 5) are plane and parallel to each other in the deployed configuration.

10. A securing method for securing a tower crane according to any one of claims 1 to 9, comprising: - a step of releasing the boom (1) in rotation on the tower around the orientation axis, to be able to be oriented in the direction of the wind; - a step of raising the boom (1) to move from the lowered position in which the wind load system (2; 3; 4; 5) is in its retracted configuration towards the raised position in which the wind load system (2; 3; 4; 5) is in its deployed configuration; wherein, during the raising of the boom (1), the wind load system (2; 3; 4; 5) moves from the retracted configuration towards the deployed configuration under the effect of its own weight alone.

11. The securing method according to claim 10, wherein the tower crane is in accordance with claim 2 and, during the raising of the boom (1), the freely movable wing element(s) (20, 21; 31; 41; 51) are freely displaced under the effect of their own weight alone to increase the surface exposed to the wind of the wind load system (2; 3; 4; 5).

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