TRAILER UNIT AND CORRESPONDING CRANE WITH AUTOMATED ASSEMBLY

Description

[0001] The invention relates to a trailer assembly.

[0002] The invention finds a preferred, and non-limiting, application for an automated assembly crane equipped with such a trailer assembly.

[0003] The invention relates more particularly to a trailer assembly comprising a chassis resting, by means of a suspension device, on a double-axle device comprising a first axle supporting first wheels and a second axle supporting second wheels; such a trailer assembly can be applied to towing on a drawbar, and also to towing on a fifth wheel also called semi-towing.

[0004] The use of a double axle device is advantageous for accepting a high load on the chassis, as is the case for a self-erecting crane, in particular to increase the lifting capacity of the crane with ballast carried by the chassis.

[0005] However, the double axle device has a reduced maneuvering capacity, compared to a single axle device, and promotes slippage phenomena, which can damage the double axle device or the terrain on which the trailer assembly maneuvers.

[0006] Indeed, during low-speed maneuvers (below a low speed threshold of around 5 to 10 km / h), necessary to correctly position the crane assembly in a final position, it is practical to be able to steer the wheels of the trailer assembly, and not just the wheels of the tractor truck pulling the trailer assembly, whether towing on a drawbar or towing on a fifth wheel.

[0007] Document EP1225734 thus proposes a trailer assembly which uses a first hydraulic steering system for synchronized steering of the first wheels and the second wheels during low-speed maneuvers. To do this, this first hydraulic steering system comprises a hydraulic cylinder which acts on the first axle, and the second axle is mechanically coupled to the first axle by a longitudinal return rod, so that with a single hydraulic cylinder it is possible to pivot the two axles at the same time, and therefore to steer the first wheels and the second wheels in synchronization. Document DE19856593A1, or its equivalent EP1037848, also describes this type of trailer assembly, for a self-erecting crane, which uses a single hydraulic cylinder associated with a longitudinal return rod to synchronize the pivoting of the two axles.

[0008] However, this first hydraulic steering system had the disadvantage of being bulky, mainly due to the use of a longitudinal steering rod which had to be large (because it was long) to transmit steering torque between the two axles. Furthermore, the synchronised steering of the two axles reduced the ability to manoeuvre in a confined space.

[0009] It is also known to use a second hydraulic steering system for synchronized steering of the first wheels and the second wheels during low-speed maneuvers. To do this, this second hydraulic steering system comprises a first hydraulic cylinder which acts on the first axle, and a second hydraulic cylinder which acts on the second axle, where the first hydraulic cylinder and the second hydraulic cylinder are connected to the same hydraulic unit which supplies them in a synchronized manner, so that it pivots the two axles at the same time, and therefore steers the first wheels and the second wheels in synchronization.

[0010] However, this second hydraulic steering system has limitations, particularly in the event of slippage (difference in grip between certain wheels) or in the event of external forces applied asymmetrically to the wheels (for example, the first wheels on the left are against an obstacle such as a sidewalk) which cause desynchronization of the wheel directions with harmful consequences for the second hydraulic steering system, and a loss of control in the maneuver.

[0011] The state of the art can also be illustrated by the teachings of document US2004 / 0221673, which proposes a trailer assembly according to the preamble of claim 1 comprising a first axle and a second axle which can be steered synchronously or independently, and a control device for controlling the directions of the first axle and the second axle. Although advantageous for low-speed maneuvers by allowing the axles to be steered independently, this trailer assembly has the disadvantage of using a steering system, for example hydraulic, which is necessarily complex because it allows the first axle and the second axle to be steered simultaneously and independently.This control of the steering of the two axles, at the same time and independently or individually, therefore also complicates the control device which must use a first steering member to steer the first axle, and a second steering member to steer the second axle, and also a selection member to select synchronized or independent steering.

[0012] The invention proposes to solve these problems in whole or in part, by proposing a trailer assembly provided with a steering system adapted to dynamically correct wheel orientation defects which would be due to slippage phenomena or to external forces applied asymmetrically to the wheels, while offering reduced bulk.

[0013] Another aim of the invention is to propose a steering system associated with a control device which is simple in terms of design and use, while making it possible to respond to the problem identified above of slippage phenomena and external forces applied asymmetrically to the wheels.

[0014] To this end, the invention provides a trailer assembly, according to claim 1, comprising a chassis, a suspension device, a double axle device, first wheels and second wheels, wherein said chassis rests, via said suspension device, on the double axle device, wherein the double axle device comprises a first axle supporting the first wheels and a second axle supporting the second wheels, and wherein the trailer assembly comprises a steering system for steering the first wheels and the second wheels when maneuvering below a low speed threshold, said steering system comprises a first actuator coupled to the first wheels, a second actuator coupled to the second wheels, and a control circuit connected to the first actuator and the second actuator, wherein said control circuit comprises a steering device configurable in a low-speed maneuvering mode in which at least one of the first actuator and the second actuator is operable to steer at least one of the first wheels and the second wheels, and wherein, in low-speed maneuvering mode, said trailer assembly being notable in that the steering device is sub-configurable between: a synchronized sub-mode in which the first actuator and the second actuator are operable in a synchronized manner to steer the first wheels and the second wheels in a synchronized manner; and a desynchronized sub-mode in which the first actuator and the second actuator are individually and independently operable to steer either only the first wheels or only the second wheels;said trailer assembly further comprising a control device connected to the steering device for: selecting either the synchronized sub-mode or the desynchronized sub-mode when the steering device is in low speed maneuvering mode; and selecting an actuation of either the first actuator or the second actuator in the desynchronized sub-mode; and in that the control device comprises: a selection member for selecting from the three sub-modes comprising the synchronized sub-mode, the desynchronized sub-mode with actuation of only the first actuator, and the desynchronized sub-mode with actuation of only the second actuator; and a steering member for steering the first wheels and the second wheels. ;

[0015] Thus, the invention proposes a control device which allows: with a selection on the selection member of the control device, to operate either in the synchronized sub-mode, or in the desynchronized sub-mode with actuation of only the first actuator, or in the desynchronized sub-mode with actuation of only the second actuator and, furthermore, by acting on the steering member of the control device, either to steer the first wheels and the second wheels in a synchronized manner if the synchronized sub-mode is selected, or to steer only the first wheels if the desynchronized sub-mode with actuation of only the first actuator is selected (the second wheels then remaining fixed), or to steer only the second wheels if the desynchronized sub-mode with actuation of only the second actuator is selected (the first wheels then remaining fixed).

[0016] Also, once in the desynchronized sub-mode, the steering device allows either the first wheels or the second wheels to be steered. In this way, an operator can choose either to steer the first wheels and the second wheels in a synchronized manner, or to steer only the first wheels, or to steer only the second wheels. In other words, the control device allows both to choose the mode or sub-mode adapted to the situation, and also to steer the wheels (either in a synchronized manner in the synchronized sub-mode, or individually and independently in the desynchronized sub-mode).

[0017] Thanks to the invention, it is therefore possible to dynamically adapt the direction of the first wheels and the second wheels, depending on the trajectory sought in a low-speed maneuver, and depending on a possible case of slippage or external forces applied asymmetrically to the wheels, and this by means of a piloting device and a simple-to-use control device.

[0018] In a particular embodiment, the control device is configurable between: a transportation mode in which the first actuator and the second actuator are non-actuatable to lock the first wheels and the second wheels in a straight position associated with straight-line travel; and the low-speed maneuvering mode; and the control device is connected to the piloting device to select either the transport mode or the low speed maneuvering mode.

[0019] In this way, during road transport, therefore at high speed, the transport mode is selected and the wheels remain straight. On the other hand, during low-speed maneuvers, and if necessary, the low-speed maneuver mode can be selected, with the choice between the desynchronized sub-mode and the desynchronized sub-mode.

[0020] According to one possibility, the selection member comprises a return means which requests a return of the selection member to the neutral position associated with the synchronized sub-mode.

[0021] This means of recall on the selection member is particularly advantageous because it allows the synchronized sub-mode to be the default sub-mode, without intervention by the operator on the selection member or in the event of release of the selection member by the operator, this synchronized sub-mode being the sub-mode which will be used most during low speed maneuvers, the two desynchronized sub-modes being exceptional sub-modes used in particular in the event of a slippage phenomenon or an external force applied asymmetrically to the wheels.

[0022] Alternatively, the steering member includes a return means that urges the steering member to return to a neutral position associated with alignment of the first wheels and second wheels in a straight position associated with straight-line travel.

[0023] This means of return on the steering organ is particularly advantageous because it allows straight line movement to be the default movement, without operator intervention on the steering organ or in the event of the operator releasing the steering organ.

[0024] According to one feature, the first actuator is a first cylinder and the second actuator is a second cylinder.

[0025] In a first embodiment, the first cylinder is a first electric cylinder, the second cylinder is a second electric cylinder, and the control circuit is an electrical circuit.

[0026] In a second embodiment, the first cylinder is a first hydraulic cylinder, the second cylinder is a second hydraulic cylinder, and the control circuit is a hydraulic control circuit hydraulically powered by at least one hydraulic unit, and this hydraulic control circuit comprises a first hydraulic sub-circuit connected to the first hydraulic cylinder and a second hydraulic sub-circuit connected to the second hydraulic cylinder, the first hydraulic sub-circuit and the second hydraulic sub-circuit being in parallel.

[0027] This parallel configuration of the first hydraulic sub-circuit and the second hydraulic sub-circuit is advantageous, because it makes it possible to make the desynchronized sub-mode with actuation of only the first actuator (which operates via the first hydraulic sub-circuit) and the desynchronized sub-mode with actuation of only the second actuator (which operates via the second hydraulic sub-circuit) more reliable, while allowing operation in the synchronized sub-mode (which operates via parallel operation of the first hydraulic sub-circuit and the second hydraulic sub-circuit).

[0028] According to one possibility, the first hydraulic sub-circuit and the second hydraulic sub-circuit are hydraulically supplied: either by a common hydraulic unit, and a flow divider is arranged between the common hydraulic unit and the first hydraulic sub-circuit and the second hydraulic sub-circuit (to distribute the hydraulic pressure equally in the two sub-circuits); or by two respective hydraulic units operating in parallel.

[0029] Alternatively, the steering device includes: a first hydraulic distributor placed on the first hydraulic sub-circuit and equipped with at least one first solenoid valve for actuating the first hydraulic cylinder, said at least one first solenoid valve being connected to the control device; and a second hydraulic distributor placed on the second hydraulic sub-circuit and equipped with at least one second solenoid valve for actuating the second hydraulic cylinder, said at least one second solenoid valve being connected to the control device.

[0030] Thus, the selection with the control device is made by acting on the first solenoid valve(s) and on the second solenoid valve(s).

[0031] In a particular embodiment, the first hydraulic cylinder is a first double-acting hydraulic cylinder connected to two first channels of the first hydraulic sub-circuit, and the second hydraulic cylinder is a second double-acting hydraulic cylinder connected to two second channels of the second hydraulic sub-circuit.

[0032] According to one characteristic, the first hydraulic distributor is a first hydraulic distributor with slides which comprises at least one first open slide associated with an actuation of the first double-acting hydraulic cylinder in a first direction, and a second open slide associated with an actuation of the first double-acting hydraulic cylinder in a second direction opposite to the first direction, and in which the at least one first solenoid valve controls the selection between the first open slide and the second open slide.

[0033] Likewise, the second hydraulic distributor is a second hydraulic slide distributor which comprises at least one first open slide associated with an actuation of the second double-acting hydraulic cylinder in a first direction, and a second open slide associated with an actuation of the second double-acting hydraulic cylinder in a second direction opposite to the first direction, and in which the at least one second solenoid valve controls the selection between the first open slide and the second open slide.

[0034] So when the synchronized sub-mode is selected, the first hydraulic spool valve and the second hydraulic spool valve are both in the same configuration: either with each the first open slide active to move the two double-acting hydraulic cylinders synchronously in the first direction; or with each the second open slide active to move the two double-acting hydraulic cylinders synchronously in the second direction.

[0035] When the desynchronized sub-mode is selected and the first double-acting hydraulic cylinder is actuated, then: the first hydraulic spool valve has either its first open spool active or its second open spool active; and the second hydraulic spool valve is for example no longer supplied or it is closed.

[0036] Similarly, when the desynchronized sub-mode is selected and it is the second double-acting hydraulic cylinder that is actuated, then: the second hydraulic spool valve has either its first spool open actively or its second spool open actively; and the first hydraulic spool valve is for example no longer supplied or it is closed.

[0037] Advantageously, the first hydraulic slide valve comprises a third closed slide valve associated with a non-actuation of the first double-acting hydraulic cylinder, and the at least one first solenoid valve comprises at least two first solenoid valves which control the selection between the first open slide valve, the second open slide valve and the third closed slide valve.

[0038] Likewise, the second hydraulic spool valve comprises a third closed spool associated with a non-actuation of the second double-acting hydraulic cylinder, and the at least one second solenoid valve comprises at least two second solenoid valves which control the selection between the first open spool, the second open spool and the third closed spool.

[0039] In other words, the third closed spool corresponds to a closing of the corresponding hydraulic spool valve.

[0040] So, when the desynchronized sub-mode is selected and it is the first double-acting hydraulic cylinder that is actuated, then: the first hydraulic spool valve has either its first spool active or its second spool active; and the second hydraulic spool valve has its third spool active, and therefore the second hydraulic spool valve is closed.

[0041] Similarly, when the desynchronized sub-mode is selected and it is the second double-acting hydraulic cylinder that is actuated, then: the second hydraulic spool valve has either its first open spool active or its second open spool active; and the first hydraulic spool valve has its third spool active, and therefore the first hydraulic spool valve is closed.

[0042] Furthermore, when transport mode is selected, each of the hydraulic spool valves has its third spool active, so they are both closed.

[0043] In an advantageous embodiment, the first two solenoid valves are each equipped with a return system requesting a selection of the third closed spool of the first hydraulic spool valve, and the second two solenoid valves are each equipped with a return system requesting a selection of the third closed spool of the second hydraulic spool valve.

[0044] Thus, in the absence of a command from the first two solenoid valves, the first hydraulic spool valve will naturally be with its third spool active, and the first hydraulic spool valve will then be closed. Similarly, in the absence of a command from the second two solenoid valves, the second hydraulic spool valve will naturally be with its third spool active, and the second hydraulic spool valve will then be closed.

[0045] According to one possibility, a first double-acting balancing valve is arranged between the first two ways of the first hydraulic sub-circuit, downstream of the first hydraulic distributor, and a second double-acting balancing valve is arranged between the second two ways of the second hydraulic sub-circuit, downstream of the second hydraulic distributor.

[0046] Between the hydraulic distributors and the double-acting hydraulic cylinders, these double-acting valves are positioned, which increase the robustness of the hydraulic control circuit in the face of external lateral forces which could cause desynchronization of the axles.

[0047] In a first embodiment, the first wheels are pivotally mounted on the first axle via first right and left pivots, and a first steering mechanism mechanically connects the first right and left pivots for common steering of the first wheels, and the first actuator is coupled to one of the first right and left pivots, and the second wheels are pivotally mounted on the second axle via second right and left pivots, and a second steering mechanism mechanically connects the second right and left pivots for common steering of the second wheels, and the second actuator is coupled to one of the second right and left pivots.

[0048] Thus, the steering of the wheels is carried out by pivoting the wheels on the axles which do not turn, according to a so-called pivot axle assembly.

[0049] In a second embodiment, the first axle is pivotally mounted on the chassis by means of a first steering ring for common orientation of the first wheels, and the first actuator is coupled to said first steering ring, and the second axle is pivotally mounted on the chassis by means of a second steering ring for common orientation of the second wheels, and the second actuator is coupled to said second steering ring

[0050] Thus, the wheels are steered by pivoting the axles, using a so-called rotating axle assembly.

[0051] Alternatively, the control device is a wireless remote control.

[0052] According to one variant, the control device is a wired control.

[0053] Alternatively, a wedging system is provided on the chassis to rest on the ground and lift the first and second wheels off the ground.

[0054] Advantageously, the timing system is a hydraulic timing system which is connected to the hydraulic unit supplying the hydraulic control circuit.

[0055] In this way, the hydraulic control circuit takes advantage of an existing hydraulic power unit to power the hydraulic rigging system, which is typically the case in a self-erecting crane. Thus, adding the function offered by the steering system requires a reduced number of components, since the hydraulic power unit is already present.

[0056] The invention also relates to a self-erecting crane comprising a mast mounted on a rotating platform and supporting a boom, said self-erecting crane further comprising a trailer assembly according to the invention, said rotating platform being mounted on the chassis of said trailer assembly, such a self-erecting crane being configurable between a transport configuration in which the mast and the boom are folded on themselves, and a working configuration in which the mast and the boom are unfolded.

[0057] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which: [ Fig 1 ] is a schematic side view of a self-erecting crane equipped with a trailer assembly according to the invention, where the self-erecting crane is in transport configuration; [ Fig 2 ] is a schematic side view of the crane trailer assembly of the Figure 1 ; [ Fig 3 ] is a schematic bottom view of the trailer assembly of the Figure 2 ; [ Fig 4 ] is a schematic view from below of one of the axles of the trailer assembly of the Figure 3 ; [ Fig 5 ] is a schematic view of a hydraulic control circuit of a steering system adapted for the trailer assembly of the Figure 2 ; [ Fig 6 ] is a schematic view of a control device when driving in a synchronized sub-mode, with the trailer assembly seen from above next to it; [ Fig 7 ] is a schematic view of the control device of the Figure 6 , when driving in a desynchronized sub-mode with actuation of only the first actuator to steer only the first wheels, with the trailer assembly seen from above; [ Fig 8 ] is a schematic view of the control device of the Figure 6 , when driving in a desynchronized sub-mode with actuation of only the second actuator to steer only the second wheels, with the trailer assembly seen from above; and [ Fig 9 ] is a schematic view of an electrical power supply circuit adapted to the invention implemented in an automated assembly crane.

[0058] The remainder of the description relates to a trailer assembly 1 according to an exemplary embodiment of the invention, intended for example to equip an automated assembly crane 9 visible in Figure 1 , it being recalled that such a trailer assembly 1 could be adapted to the transport of other types of loads.

[0059] The self-erecting crane 9 comprises a mast 91 mounted on a rotating platform 92 and supporting a boom 93, where the self-erecting crane 9 is configurable between: a transport configuration, illustrated in the Figure 1 , in which the mast 91 and the boom 93 are folded back on themselves; and a working configuration (not shown) in which the mast 91 and the boom 93 are unfolded.

[0060] The self-erecting crane 9 thus comprises a folding / unfolding mechanism which acts on the mast 91 to fold and unfold the crane and thus move it from the working configuration to the transport configuration, and vice versa.

[0061] In order to be able to transport the self-erecting crane 9, in transport configuration, the mast 91 supports a coupling element provided with a coupling pin 94 suitable for coupling to a fifth wheel SE provided on a rear platform of a tractor truck CT, as shown in the Figure 1 In this way, the self-erecting crane 9 can be transported on a fifth wheel.

[0062] It is also conceivable that the self-assembly crane 9 may, as a variant or as an option, comprise a towing drawbar 95 which is mounted on the mast 91; such a towing drawbar 95 having a coupling head suitable for being coupled to a towing element of a towing truck (of the trailer type). In the version illustrated in Figure 1 , the towing drawbar 95 is retractable and can therefore be in a retracted position which is used during transport on a fifth wheel or in a working configuration, and in a deployed position which is used only during transport on a drawbar.

[0063] The rotating platform 92 is pivotally mounted along a vertical axis on the trailer assembly 1 which comprises a chassis 10 resting, by means of a suspension device, on a double-axle device comprising a first axle 11 supporting first wheels 21 and a second axle 12 supporting second wheels 22.

[0064] The suspension device comprises for example a first leaf spring suspension 110 supporting the first axle 11, and a second leaf spring suspension 120 supporting the second axle 12.

[0065] In the embodiment illustrated in the Figures 3 And 4 , the first wheels 21 are pivotally mounted on the first axle 11 via first right and left pivots 111, and a first steering mechanism 112 (formed for example by a connecting rod) mechanically connects the first right and left pivots 111 for a common orientation of the first wheels 21.

[0066] Likewise, the second wheels 22 are pivotally mounted on the second axle 12 via second right and left pivots 121, and a second steering mechanism (formed for example by a connecting rod) mechanically connects the second right and left pivots 121 for a common orientation of the second wheels 22.

[0067] This trailer assembly 1 comprises a steering system for steering the first wheels 21 and the second wheels 22 during maneuvers below a low speed threshold, for example 5 to 10 km / h, also called low speed maneuvers used to steer the trailer assembly 1, and therefore the self-erecting crane 9.

[0068] This steering system is a hydraulic steering system which includes: a first actuator which is in the form of a first double-acting hydraulic cylinder 31 (hereinafter called first cylinder 31) coupled to the first wheels 21, and more specifically coupled to one of the first right and left pivots 111, a second actuator which is in the form of a second double-acting hydraulic cylinder 32 (hereinafter called second cylinder 32) coupled to the second wheels 22, and more specifically coupled to one of the second right and left pivots 121.

[0069] Thus, the first cylinder 31 makes it possible to steer (or turn) the first wheels 21, while the second cylinder 32 makes it possible to steer (or turn) the second wheels 22. The first wheels 21 and the second wheels 22 are not mechanically coupled or linked in rotation, so that the first cylinder 31 turns only the first wheels 21, and not the second wheels 22, and the second cylinder 32 turns only the second wheels 22, and not the first wheels 21.

[0070] In reference to the Figure 5 , the hydraulic steering system further comprises a hydraulic control circuit 4 connected to the first cylinder 31 and to the second cylinder 32, and supplied by a hydraulic unit 5. This hydraulic control circuit 4 comprises: a first hydraulic sub-circuit 41 connecting the first cylinder 31 to the hydraulic unit 5; and a second hydraulic sub-circuit 42 connecting the second cylinder 32 to the hydraulic unit 5.

[0071] The first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42 are thus in parallel and are both supplied by the hydraulic unit 5. A flow divider 43 is arranged between the hydraulic unit 5 and the first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42, to distribute the hydraulic pressure equally between the first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42.

[0072] This hydraulic power unit 5 can be carried by the chassis 10, as seen in the Figures 1 And 2. It is further advantageous for this hydraulic unit 5 to be shared with another hydraulic system used in the trailer assembly 1, and for example in the self-erecting crane 9. For example, such a trailer assembly 1 may comprise a hydraulic wedging system 15 provided on the chassis 10 to rest on the ground and lift the wheels off the ground in the working configuration. Such a hydraulic wedging system 15 comprises several hydraulic cylinders 16 connected to the hydraulic unit 5.

[0073] In a variant not illustrated, the first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42 are supplied by two respective hydraulic units operating in parallel, with equivalent hydraulic pressures between the first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42.

[0074] The first hydraulic sub-circuit 41 and the second hydraulic sub-circuit 42 are identical, and the first cylinder 31 and the second cylinder 32 are also identical, so that their descriptions will be made jointly in the following.

[0075] The first hydraulic sub-circuit 41 (respectively the second hydraulic sub-circuit 42) comprises two first channels 410, 411 (respectively 420, 421), namely: a first supply path 410 (respectively 420) which provides the supply pressure and which is connected to a hydraulic pump 50 of the hydraulic unit 5; and a first return path 411 (respectively 421) which allows the exhaust and which is connected to a reservoir 51 of the hydraulic unit 5.

[0076] The first cylinder 31 (respectively the second cylinder 32) comprises a cylinder in which slides a piston 312 (respectively 322) secured to a rod 313 (respectively 323) articulated on one of the first right and left pivots 111 (respectively one of the second right and left pivots 121). This cylinder has a compression chamber 310 (respectively 320) and an expansion chamber 311 (respectively 321) arranged on either side of the piston 312 (respectively 322).

[0077] Two actuations of the first cylinder 31 (respectively second cylinder 32) are therefore possible: a compression actuation, in which the compression chamber 310 (respectively 320) is in fluid connection with the first supply path 410 (respectively 420) and the expansion chamber 311 (respectively 321) is in fluid connection with the first return path 411 (respectively 421), thus providing compression of the rod 313 (respectively 323) which retracts, which corresponds to an actuation of the first cylinder 31 (respectively second cylinder 32) in a first direction, to direct the first wheels 21 (respectively second wheels 22) in a first direction;an expansion actuation, in which the expansion chamber 311 (respectively 321) is in fluid connection with the first supply path 410 (respectively 420) and the compression chamber 310 (respectively 320) is in fluid connection with the first return path 411 (respectively 421), thus providing an expansion of the rod 313 (respectively 323) which deploys, which corresponds to an actuation of the first cylinder 31 (respectively second cylinder 32) in a second direction opposite to the first direction, to direct the first wheels 21 (respectively second wheels 22) in a second direction, opposite to the first direction. ;

[0078] The flow divider 43 is positioned between the first supply path 410 and the second supply path 420 to distribute the hydraulic pressure from the hydraulic pump 50.

[0079] The hydraulic control circuit 4 includes a control device which integrates: a first hydraulic slide valve distributor 61 (hereinafter called first distributor 61) placed on the first hydraulic sub-circuit 41, upstream of the first cylinder 31, and more specifically; and a second hydraulic slide valve distributor 62 (hereinafter called second distributor 62) placed on the second hydraulic sub-circuit 42, upstream of the second cylinder 32.

[0080] The first distributor 61 and the second distributor 62 are identical, so that their descriptions will be made jointly in the following.

[0081] The first distributor 61 (respectively the second distributor 62) is a distributor of the 4 / 3 type, that is to say with four ways and three spools (or three positions), and in particular a closed center distributor. This first distributor 61 (respectively 62) comprises: a first open slide valve 611 (respectively 621) which fluidically connects the first supply path 410 (respectively second supply path 420) and the compression chamber 310 (respectively 320) of the first cylinder 31 (respectively second cylinder 32) and which fluidically connects the first return path 411 (respectively second return path 421) and the expansion chamber 311 (respectively 321) of the first cylinder 31 (respectively second cylinder 32), so that this first open slide valve 611 (respectively 621) is associated with an actuation of the first cylinder 31 (respectively second cylinder 32) in the first direction (compression actuation);a second open slide valve 612 (respectively 622) which fluidically connects the first supply path 410 (respectively second supply path 420) and the expansion chamber 311 (respectively 321) of the first cylinder 31 (respectively second cylinder 32) and which fluidically connects the first return path 411 (respectively second return path 421) and the compression chamber 310 (respectively 320) of the first cylinder 31 (respectively second cylinder 32), so that this second open slide valve 612 (respectively 622) is associated with an actuation of the first cylinder 31 (respectively second cylinder 32) in the second direction (expansion actuation);a third closed drawer 613 (respectively 623), forming a central drawer interposed between the first open drawer 611 (respectively 621) and the second open drawer 612 (respectively 622), and which closes the fluid connections between the first cylinder 31 (respectively second cylinder 32) and the two channels 410, 411 (respectively 420, 421), so that this third closed drawer 613 (respectively 623) is associated with a non-actuation of the first cylinder 31 (respectively second cylinder 32).;

[0082] The first distributor 61 (respectively the second distributor 62) is equipped with two first solenoid valves 65, 66 (respectively two second solenoid valves 67, 68) which control the selection between the first open spool 611 (respectively 621), the second open spool 612 (respectively 622) and the third closed spool 613 (respectively 623).

[0083] These two first solenoid valves 65, 66 (respectively two second solenoid valves 67, 68) are both equipped with a return system urging towards a selection of the third closed spool 613 (respectively 623). In other words, the return systems (such as for example springs) on each side of the first distributor 61 (respectively second distributor 62) return the first distributor 61 (respectively second distributor 62) to the central (neutral) position when the first solenoid valves 65, 66 (respectively two second solenoid valves 67, 68) are not activated (or energized).

[0084] More precisely, the first solenoid valves 65, 66 (respectively second solenoid valves 67, 68) comprise a first right solenoid valve 65 (respectively a second right solenoid valve 67) and a first left solenoid valve 66 (respectively a second left solenoid valve 68), and: an activation of the first right solenoid valve 65 (respectively second right solenoid valve 67) positions a selection of the first open slide 611 (respectively 621), and therefore controls an actuation of the first cylinder 31 (respectively second cylinder 32) in the first direction (compression actuation); an activation of the first left solenoid valve 66 (respectively second left solenoid valve 68) positions a selection of the second open slide 612 (respectively 622), and therefore controls an actuation of the first cylinder 31 (respectively second cylinder 32) in the second direction (expansion actuation); and non-activation of the first two solenoid valves 65, 66 (respectively second solenoid valves 67, 68) positions a selection of the third closed drawer 613 (respectively 623), and therefore non-actuation of the first cylinder 31 (respectively second cylinder 32).

[0085] Furthermore, a first double-acting balancing valve 71 is arranged between the two first ways 410, 411 of the first hydraulic sub-circuit 41, downstream of the first distributor 61, and a second double-acting balancing valve 72 is arranged between the two second ways 420, 421 of the second hydraulic sub-circuit 42, downstream of the second distributor 62.

[0086] Thus, the steering device is configurable in a low-speed maneuvering mode in which at least one of the first cylinder 31 and the second cylinder 32 is actuable to steer at least one of the first wheels 21 and the second wheels 22.

[0087] More precisely, in this low speed maneuvering mode, the piloting device is sub-configurable between: a synchronized sub-mode “SMS” in which the first cylinder 31 and the second cylinder 32 are actuable in a synchronized manner to steer the first wheels 21 and the second wheels 22 in a synchronized manner; and a desynchronized sub-mode “SMD” in which the first cylinder 31 and the second cylinder 32 are actuable individually and independently to steer either only the first wheels 21 or only the second wheels 22.

[0088] The trailer assembly 1 further comprising a control device 8, visible on the Figures 6 à 8 , connected to the control device, and more precisely connected to the four solenoid valves 65, 66, 67, 68 for: selecting either the synchronized sub-mode “SMS” or the desynchronized sub-mode “SMD” when the control device is in low speed maneuvering mode; and selecting an actuation of either the first cylinder 31 or the second cylinder 32 when the desynchronized sub-mode “SMD” is selected.

[0089] This control device 8 is for example a remote control, for wireless and remote control. This control device 8 comprises for example two joysticks, a direction joystick 81 and a selection joystick 82.

[0090] The selection lever 82 is used for selecting the synchronized sub-mode “SMS”, the desynchronized sub-mode “SMD” and for selecting the actuation of either the first cylinder 31 or the second cylinder 32 in the desynchronized sub-mode “SMD”.

[0091] The 82 selection lever thus offers three positions: a neutral position associated with the synchronized sub-mode “SMS”, which on the Figure 6 corresponds to a central position; a position associated with the desynchronized sub-mode “SMD” and the actuation “A1” of the first cylinder 31 alone (or sub-mode “SMD-A1”), which on the Figure 7 corresponds to a high position; and a position associated with the desynchronized sub-mode “SMD” and the actuation “A2” of the second cylinder 32 alone (or sub-mode “SMD-A2”), which on the Figure 8 corresponds to a low position.

[0092] This control device 8 is provided with a return means which requests a return of the selection lever 82 to the neutral position associated with the synchronized sub-mode “SMS”. Also, in the absence of an action on the selection lever 82, it is the synchronized sub-mode “SMS” which is selected by default.

[0093] The steering lever 81 is used to steer the wheels 21, 22 in the first direction (for example by pushing it to the right) or in the second direction (for example by pushing it to the left). This control device 8 is provided with a return means which requests a return of the steering lever 81 to a neutral position associated with an alignment of the wheels 21, 22 in a straight position associated with a straight line movement.

[0094] In reference to the Figure 6 , when the selection lever 82 is in the position associated with the synchronized sub-mode “SMS”, the control device 8 activates in a synchronized manner: either the first right solenoid valve 65 and the second right solenoid valve 67 to control a synchronized actuation of the first cylinder 31 and the second cylinder 32 in the first direction, and therefore steer the first wheels 21 and the second wheels 22 in a synchronized manner in the first direction (if the steering lever 81 is acted upon for a direction in the first direction); or the first left solenoid valve 66 and the second left solenoid valve 68 to control a synchronized actuation of the first cylinder 31 and the second cylinder 32 in the second direction, and therefore steer the first wheels 21 and the second wheels 22 in a synchronized manner in the second direction (if the steering lever 81 is acted upon for a direction in the second direction).

[0095] In reference to the Figure 7 , when the selection lever 82 is in the position associated with the desynchronized sub-mode “SMD” and the actuation “A1” of the first cylinder 31 alone (or sub-mode “SMD-A1”), the control device 8 activates: either only the first right solenoid valve 65 to control an actuation of only the first cylinder 31 in the first direction, and therefore steer only the first wheels 21 in the first direction (if the steering lever 81 is acted upon for a direction in the first direction), the second wheels 22 remaining in the right position; or only the first left solenoid valve 66 to control an actuation of only the first cylinder 31 in the second direction, and therefore steer only the first wheels 21 in the second direction (if the steering lever 81 is acted upon for a direction in the second direction), the second wheels 22 remaining in the right position.

[0096] In reference to the Figure 8 , when the selection lever 82 is in the position associated with the desynchronized sub-mode “SMD” and the actuation “A2” of the second cylinder 32 alone (or sub-mode “SMD-A2”), the control device 8 activates: either only the second right solenoid valve 67 to control an actuation of only the second cylinder 32 in the first direction, and therefore steer only the second wheels 22 in the first direction (if the steering lever 81 is acted upon for a direction in the first direction), the first wheels 21 remaining in the right position; or only the second left solenoid valve 68 to control an actuation of only the second cylinder 32 in the second direction, and therefore steer only the second wheels 22 in the second direction (if the steering lever 81 is acted upon for a direction in the second direction).

[0097] The steering device is also configurable in a transport mode in which the first cylinder 31 and the second cylinder 32 are non-actuable to lock the wheels 21, 22 in the straight position associated with straight-line travel.

[0098] In this mode of transport, the four solenoid valves 65, 66, 67, 68 are not activated, and thus the two cylinders 31, 32 are not actuated.

[0099] The control device 8 is connected to the piloting device to select either the transport mode or the low speed maneuvering mode.

[0100] This transport mode corresponds to the neutral mode which associates the neutral position of the selection lever 82 and the neutral position of the steering lever 81. Thus, the neutral position of the selection lever 82 is associated with both the synchronized sub-mode “SMS” and the transport mode, it is only if one acts or not on the steering lever 81 that one passes from one to the other.

[0101] There Figure 9illustrates an electrical power supply circuit 83 suitable for a self-erecting crane. Indeed, conventionally, a self-erecting crane is equipped with an electrical cabinet 84 powered by an autonomous electrical source 85, for example arranged on the chassis 10, comprising one or more electric batteries. Standard cabling 86 connects the electrical cabinet 84 to solenoid valves 17 controlling the hydraulic cylinders 16 of the hydraulic wedging system 15, and to an electric motor 500 of the hydraulic pump 50 of the hydraulic unit 5. These elements 84, 85, 86, 860, 500 are already present on the self-erecting crane.

[0102] For the electrical power supply of the hydraulic steering system described above, secondary wiring 87 is provided to connect the electrical cabinet 84 and the autonomous electrical source 85 to a secondary electrical unit 88, itself connected to the four solenoid valves 65, 66, 67, 68. This secondary electrical unit 88 can also be connected to an additional solenoid valve 89 which is used to connect the hydraulic unit 5 either to the hydraulic wedging system 15 (once the crane is stopped), or to the hydraulic steering system and its hydraulic control circuit 4 (during low-speed maneuvers).

[0103] Thus the electrical power supply for the hydraulic steering system is integrated into the crane, and is therefore economical because it does not require a dedicated central unit or a dedicated source. Similarly, the control device 8 is preferably the one already used to control the crane in its various functions (folding / unfolding, lifting and distribution, wedging, etc.).

Claims

1. A trailer assembly (1), comprising a chassis (10), a suspension device (110, 120), a double-axle device (110, 120), first wheels (21) and second wheels (22), where said chassis (10) rests, via said suspension device (110, 120), on said double-axle device, wherein the double-axle device comprises a first axle (11) supporting said first wheels (21) and a second axle supporting said second wheels (22), and wherein the trailer assembly (1) comprises a steering system to steer the first wheels (21) and the second wheels (22) during maneuvers below a low speed threshold, said steering system comprises a first actuator (31) which is coupled to the first wheels (21), a second actuator (32) which is coupled to the second wheels (22), and a control circuit (4) connected to the first actuator (31) and to the second actuator (32), wherein said control circuit (4) comprises a driving device (61, 62) configurable in a low speed maneuvering mode in which at least one of the first actuator (31) and the second actuator (32) can be actuated to steer at least one of the first wheels (21) and the second wheels (22), said trailer assembly (1) being characterized in that, in the low speed maneuvering mode, the driving device (61, 62) is sub-configurable between: - a synchronized sub-mode in which the first actuator (31) and the second actuator (32) can be actuated in a synchronized manner to steer the first wheels (21) and the second wheels (22) in a synchronized manner; and - a desynchronized sub-mode in which the first actuator (31) and the second actuator (32) can be actuated individually and independently to steer either only the first wheels (21) with the second wheels (22) fixed in a desynchronized sub-mode with actuation of the first actuator (31) alone, or only the second wheels (22) with the first wheels (21) fixed in a desynchronized sub-mode with actuation of the second actuator (32) alone; said trailer assembly (1) further comprising a control device (8) which is connected to the driving device (61, 62), said control device (8) being a wireless remote control or a wired control configured to: - select either the synchronized sub-mode or the desynchronized sub-mode when the driving device (61, 62) is in the low speed maneuvering mode; and - select an actuation either of the first actuator (31) or of the second actuator (32) in the desynchronized sub-mode; and wherein the control device (8) includes: - a selection member (82) to select among the three sub-modes comprising the synchronized sub-mode, the desynchronized sub-mode with actuation of the first actuator (31) alone, and the desynchronized sub-mode with actuation of the second actuator (32) alone; and - a steering member (81) to steer the first wheels (21) and the second wheels (22), said steering member (81) being configured to: - steer the first wheels (21) and the second wheels (22) in a synchronized manner if it is the synchronized sub-mode which is selected; - steer the first wheels (21) alone if it is the desynchronized sub-mode with actuation of the first actuator (31) alone which is selected, the second wheels (22) then remaining fixed; - steer the second wheels (22) alone if it is the desynchronized sub-mode with actuation of the second actuator (32) alone which is selected, the first wheels (21) then remaining fixed.

2. The trailer assembly (1) according to claim 1, wherein the driving device (61, 62) is configurable between: - a transport mode in which the first actuator (31) and the second actuator (32) cannot be actuated to lock the first wheels (21) and the second wheels (22) in a straight position associated to a straight-line displacement; and - the low speed maneuvering mode; and the control device (8) is connected to the driving device (61, 62) to select either the transport mode, or the low speed maneuvering mode.

3. The trailer assembly (1) according to claim 1 or 2, wherein the selection member (82) comprises return means which biases a return of the selection member (82) into the neutral position associated to the synchronized sub-mode.

4. The trailer assembly (1) according to any one of the preceding claims, wherein the steering member (81) comprises return means which biases a return of the steering member (81) into a neutral position associated to an alignment of the first wheels (21) and the second wheels (22) in a straight position associated to a straight-line displacement.

5. The trailer assembly (1) according to any one of the claims 1 to 4, wherein the first actuator is a first cylinder (31) and the second actuator is a second cylinder (32).

6. The trailer assembly (1) according to claim 5, wherein the first cylinder is a first hydraulic cylinder (31), the second cylinder is a second hydraulic cylinder (32), and the control circuit (4) is a hydraulic control circuit (4) hydraulically powered by at least one hydraulic power plant (5), and said hydraulic control circuit (4) comprises a first hydraulic sub-circuit (41) connected to the first hydraulic cylinder (31) and a second hydraulic sub-circuit (42) connected to the second hydraulic cylinder (32), the first hydraulic sub-circuit (41) and the second hydraulic sub-circuit (42) being in parallel.

7. The trailer assembly (1) according to claim 7, wherein the first hydraulic sub-circuit (41) and the second hydraulic sub-circuit (42) are hydraulically powered: - either by a common hydraulic power plant (5), and a flow divider (43) is disposed between the common hydraulic power plant (5) and the first hydraulic sub-circuit (41) and the second hydraulic sub-circuit (42); - or by two respective hydraulic power plants operating in parallel.

8. The trailer assembly (1) according to any one of claims 6 and 7, wherein the driving device comprises: - a first hydraulic distributor (61) placed on the first hydraulic sub-circuit (41) and equipped with at least one first solenoid valve (65, 66) to actuate the first hydraulic cylinder (31), said at least one first solenoid valve (65, 66) being in connection with the control device (8); and - a second hydraulic distributor (62) placed on the second hydraulic sub-circuit (42) and equipped with at least one second solenoid valve (67, 68) to actuate the second hydraulic cylinder (32), said at least one second solenoid valve (67, 68) being in connection with the control device (8).

9. The trailer assembly (1) according to claim 8, wherein the first hydraulic cylinder (31) is a first double-acting hydraulic cylinder joined to two first ways of the first hydraulic sub-circuit (41), and the second hydraulic cylinder (32) is a second double-acting hydraulic cylinder joined to two second ways of the second hydraulic sub-circuit (42).

10. The trailer assembly (1) according to claim 9, wherein: - the first hydraulic distributor (61) is a first hydraulic spool valve which comprises at least one first open spool (611) associated to an actuation of the first double-acting hydraulic cylinder (31) in a first direction, and one second open spool (612) associated to an actuation of the first double-acting hydraulic cylinder (31) in a second direction opposite to the first direction, and in which the at least one first solenoid valve (65, 66) controls the selection between the first open spool (611) and the second open spool (612); - the second hydraulic distributor (62) is a second hydraulic spool valve which comprises at least one first open spool (621) associated to an actuation of the second double-acting hydraulic cylinder (32) in a first direction, and one second open spool (622) associated to an actuation of the second double-acting hydraulic cylinder (32) in a second direction opposite to the first direction, and in which the at least one second solenoid valve (67, 68) controls the selection between the first open spool (621) and the second open spool (622).

11. The trailer assembly (1) according to claim 10, wherein: - the first hydraulic spool valve (61) comprises a third closed spool (613) associated to a non-actuation of the first double-acting hydraulic cylinder (31), and the at least one first solenoid valve comprises at least two first solenoid valves (65, 66) which control the selection between the first open spool (611), the second open spool (612) and the third closed spool (613); and - the second hydraulic spool valve (62) comprises a third closed spool (623) associated to a non-actuation of the second double-acting hydraulic cylinder (32), and the at least one second solenoid valve comprises at least two second solenoid valves (67, 68) which control the selection between the first open spool (621), the second open spool (622) and the third closed spool (623).

12. The trailer assembly (1) according to claim 11, wherein the two first solenoid valves (65, 66) are each equipped with a return system biasing towards a selection of the third closed spool (613) of the first hydraulic spool valve (61), and the two second solenoid valves (67, 68) are each equipped with a return system biasing towards a selection of the third closed spool (623) of the second hydraulic spool valve (62).

13. The trailer assembly (1) according to any one of the claims 9 to 12, wherein a first double-acting balancing valve (71) is disposed between the two first ways of the first hydraulic sub-circuit (41), downstream of the first hydraulic distributor (61), and a second double-acting balancing valve (72) is disposed between the two second ways of the second hydraulic sub-circuit (42), downstream of the second hydraulic distributor (62).

14. The trailer assembly (1) according to claim 6, wherein a wedging system (15) is provided on the chassis (10) to bear on ground and take off the first wheels (21) and the second wheels (22) from the ground, and wherein the wedging system (15) is a hydraulic wedging system which is connected to the hydraulic power plant (5) powering the hydraulic control circuit (4).

15. A self-erecting crane (9) comprising a mast (91) which is mounted on a rotating platform (92) and supporting a boom (93), said self-erecting crane (9) further comprising a trailer assembly (1) according to any one of the preceding claims, said rotating platform (92) being mounted on the chassis (10) of said trailer assembly (1), said self-erecting crane (9) being configurable between a transport configuration in which the mast (91) and the boom (93) are folded back on themselves, and a working configuration in which the mast (91) and the boom are unfolded.