EP0391808A1 - Telescopic hoisting device for a vehicle, in particular for a loader - Google Patents

Telescopic hoisting device for a vehicle, in particular for a loader Download PDF

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Publication number
EP0391808A1
EP0391808A1 EP90400948A EP90400948A EP0391808A1 EP 0391808 A1 EP0391808 A1 EP 0391808A1 EP 90400948 A EP90400948 A EP 90400948A EP 90400948 A EP90400948 A EP 90400948A EP 0391808 A1 EP0391808 A1 EP 0391808A1
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EP
European Patent Office
Prior art keywords
cylinder
deployment
tool
articulated
discharge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90400948A
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German (de)
French (fr)
Inventor
Jean Hugues Faivre
Philippe Champion
Henri Dupré
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
FDI- SAMBRON SA
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FDI- SAMBRON SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by FDI- SAMBRON SA filed Critical FDI- SAMBRON SA
Publication of EP0391808A1 publication Critical patent/EP0391808A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/065—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks non-masted
    • B66F9/0655—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks non-masted with a telescopic boom
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/34—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with bucket-arms, i.e. a pair of arms, e.g. manufacturing processes, form, geometry, material of bucket-arms directly pivoted on the frames of tractors or self-propelled machines
    • E02F3/3405—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with bucket-arms, i.e. a pair of arms, e.g. manufacturing processes, form, geometry, material of bucket-arms directly pivoted on the frames of tractors or self-propelled machines and comprising an additional linkage mechanism
    • E02F3/3408—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with bucket-arms, i.e. a pair of arms, e.g. manufacturing processes, form, geometry, material of bucket-arms directly pivoted on the frames of tractors or self-propelled machines and comprising an additional linkage mechanism of the parallelogram-type
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/431—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like
    • E02F3/432—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like for keeping the bucket in a predetermined position or attitude
    • E02F3/433—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like for keeping the bucket in a predetermined position or attitude horizontal, e.g. self-levelling

Definitions

  • the invention relates to a telescopic lifting structure for a machine such as a self-propelled loader.
  • telescopic loader arm essentially consisting of at least one telescopic loader arm (single or double) articulated to the chassis of the machine.
  • a tool such as a bucket, palletizer, jib, backfill blade, sweeper, bucket, rake rake or other is articulated at the free end of the loader arm.
  • the telescopic arm comprises at least two segments, the first of which is associated articulated with but integral with the chassis and the other of which slides inside the first under the action of a deployment cylinder disposed inside the and supported on the first segment.
  • the tool is articulated at the free end of the second sliding segment and its attitude can be adjusted under the action of a tilting cylinder bearing on the second sliding segment and whose actuating rod is mechanically connected to the tool. Furthermore, the inclination of the telescopic loader arm is adjustable by means of a lifting cylinder bearing on the chassis and mechanically connected to the first segment of this arm.
  • the outlet chamber of the lifting cylinder is directly connected to the inlet chamber of the discharge cylinder placed at the end of the second sliding segment.
  • the volume of fluid displaced in the outlet chamber of the lifting cylinder is fully transmitted, by the hydraulic connection, to the inlet chamber of the discharge cylinder.
  • the lifting cylinder generally has to develop a greater force than the dumping cylinder.
  • a fourth metering cylinder placed parallel to the lifting cylinder, but dimensioned similarly to the dumping cylinder to which it is hydraulically connected in the same way as the lifting cylinder in the first. aforementioned variant.
  • the metering cylinder then follows the lifting cylinder in the tilting movement and the volume of fluid displaced in its outlet chamber is fully transmitted to the inlet chamber of the discharge cylinder which is thus automatically controlled.
  • This second solution nevertheless has the disadvantage of requiring an additional cylinder which increases the final cost of the structure.
  • the presence of the discharge cylinder at the head of the loader arm means that the telescopic loader arm must be dimensioned accordingly, which has the consequence of making the structure heavier and increasing its cost price.
  • the external connecting pipes between the two cylinders are subjected to bad weather and to shocks and wear, in particular because they extend in the immediate vicinity of the tool.
  • hydraulic compensation is not considered to be strong enough for important works such as earthworks.
  • the present invention aims to remedy these drawbacks and aims to propose a lifting structure with a telescopic arm: - with which the adjustment of the attitude of the tool is carried out automatically in a proportional manner over the entire lifting stroke and this in a simple and economical manner.
  • the different cylinders, the loader arm and the motorization are only dimensioned as a function of mechanical constraints, and therefore independently of the requirements for correcting the attitude of the tool - which does not require the presence of an additional metering cylinder - whose discharge cylinder is not placed at the head of the loader arm, but on the contrary as close as possible to the articulation of this arm to the chassis - which does not have hydraulic connection lines in the vicinity of the tool.
  • - which is of sufficient strength and reliability, in particular equivalent to that of non-telescopic structures, to ensure important work such as earthworks.
  • the present invention aims to propose such a lifting structure whose performance-to-weight and performance-to-cost ratios (cost price and operating costs) are higher than those of known structures.
  • the invention provides a lifting structure for a machine such as a loader comprising at least one telescopic loader arm consisting of at least two segments, the first of which is articulated by one of its ends to the chassis of the machine. so as to be able to pivot at least in a vertical plane around a horizontal pivot axis under the action of a lifting cylinder, and the second of which slides along an axis of deployment / retraction relative to the first under the action a deployment cylinder, the structure also comprising an associated tool articulated at the free end of the loader arm so as to be able to pivot at least in said vertical plane around a horizontal pivot axis under the action of a cylinder discharge, characterized in that it comprises a mechanical system of articulated connecting rods and levers making it possible to automatically maintain constant the attitude of the tool during modifications of the inclination of the load arm r, and in that the discharge and deployment jacks are hydraulically connected so as to automatically maintain constant the attitude of the tool during deployment and during the retraction of the
  • the discharge cylinder is integrated into the mechanical system, its cylinder being articulated and bearing on a first member of this mechanical system, its actuating rod being articulated to a second member of the mechanical system, so that this cylinder constitutes a connecting rod variable length for this mechanical system.
  • the first member is associated with the first segment of the loader arm
  • the second member is associated with the structure near the tool
  • the discharge cylinder extends at least substantially parallel to the deployment cylinder
  • the cylinder travel stroke discharge corresponds to that of the deployment cylinder increased by the stroke necessary for the pivoting movements of the tool in each extreme deployed and retracted position of the loader arm and of the deployment cylinder.
  • Said first member is a first lever articulated at the first segment around a horizontal pivot axis
  • said second member is a second lever articulated at the free end of the loader arm around a horizontal pivot axis.
  • the first lever is connected to the pivot axis connecting the lifting cylinder to the frame of the structure by a first connecting rod articulated to this first lever and to this axis.
  • the second lever is connected to the tool by means of a second link articulated to this second lever and to this tool.
  • each of the deployment and discharge cylinders is a double-acting cylinder controlled from a double inlet / outlet valve connected to the inlet and outlet chambers of this jack by a control circuit; the discharge cylinder is mounted in series in the control circuit of the deployment cylinder; and the control valve of the discharge cylinder is connected directly in parallel to the chambers of this cylinder.
  • the two chambers respectively of the discharge cylinder and the redeployment cylinder which are directly connected to each other, both both have the same section.
  • the discharge cylinder and the deployment cylinder are provided with flow regulating valves avoiding any offset between these cylinders, which would be due for example to cavitation phenomena.
  • the automatic compensation of the trim of the tool is carried out mechanically by the mechanical system during modifications of the inclination of the loader arm, and hydraulically by the hydraulic connections between the discharge cylinder and the cylinder deployment when changing the length of the telescopic loader arm.
  • the invention also relates to a self-propelled loader characterized in that it is equipped with a lifting structure according to the invention.
  • FIG. 1 The figures show a self-propelled loader 1 equipped with a lifting structure with telescopic arm according to the invention.
  • a loader 1 comprises a chassis 3 - in particular in several articulated parts - supporting a plurality of axles and wheels or tracks 4, a station or a cockpit 5, and a powertrain 6 capable of supplying a control fluid under pressure - in particular oil - intended for the different cylinders allowing the functioning of the lifting structure 2.
  • the lifting structure 2 comprises at least one telescopic loader arm 7 consisting of at least two segments 7a, 7b of which the first 7a is articulated by an 8 of its ends 8, 9 to the chassis 3 of the machine 1 so as to be able to pivot at least in a vertical plane around a horizontal pivot axis 10 under the action of a lifting cylinder 11.
  • This lifting cylinder 11 is articulated by its cylinder 13 to the chassis 3 around a horizontal pivot axis 12 located at a distance from and at a level lower than the horizontal pivot axis 10 connecting the first segment 7a to the chassis 3.
  • the free end 14 of the actuating rod 15 of the lifting cylinder 11 is also articulated under the first segment 7a about a horizontal pivot axis 16.
  • the second segment 7b of the loader arm 7 slides along a deployment / retraction axis 17 relative to the first segment 7a under the action of a deployment cylinder 18.
  • the deployment / retraction axis 17 is perpendicular to the axis of horizontal pivoting 10 for associating the first segment 7a with the chassis 3.
  • the cylinder 19 of this deployment cylinder 18 is rigidly associated with and bears on the bottom of the first segment 7a of the loader arm 7.
  • the actuating rod 21 of the cylinder deployment 18 is rigidly associated with an internal frame 22 of the second segment 7b.
  • the deployment cylinder 18 is therefore placed inside the first segment 7a which is hollow and controls the second segment 7b, also hollow, in its sliding for the deployment or retraction of the telescopic loader arm 7.
  • the second segment 7b enters the first segment 7a through the hollow free end of this first segment 7a.
  • the cross sections of these segments are in correspondence to allow them to slide relative to each other. Appropriate guide members, known in
  • the lifting structure 2 also comprises an associated tool 23 articulated at the free end 24 of the loader arm 7 so as to be able to pivot at least in said vertical plane around a horizontal pivot axis 25 under the action a discharge cylinder 26.
  • the free end 24 of the loader arm 7 to which the tool 23 is articulated is also the free end of the second segment 7b.
  • the tool 23 may consist of a bucket, a palletizing fork, a jib, a backfill blade, a sweeper, a bucket, a swather rake, or the like. In Figures 1 to 3 the tool 23 has been shown in the form of a palletizing fork.
  • the tool 23 shown is a bucket.
  • the tool 23 is articulated at the free end 24 of the loader arm 7 by means of a rapid adaptation mechanism 27 known per se, making it possible to interchange the tool 23.
  • the tool 23 is connected to the free end 28 of the actuating rod 29 of the discharge cylinder 26, in particular by means of a connecting rod 33, a lever 32, and the adaptation mechanism 27.
  • the lifting cylinder 11 is a double-acting cylinder and makes it possible to modify the inclination of the loader arm 7 relative to the horizontal, in the direction of lifting or in that of lowering.
  • the deployment cylinder 18 is a double-acting cylinder, and allows the modification of the length of the telescopic loader arm 7 in the direction of deployment or in that of retraction.
  • the discharge cylinder 26 is a double-acting cylinder, and makes it possible to pivot the tool 23 about its horizontal pivot axis 25 in the direction of the discharge, or in that of the loading.
  • the cylinders 11, 18, 26 lifting, deployment and dumping also allow the maintenance of the lifting structure 2 in a determined position.
  • the lifting structure 2 can comprise a single telescopic loader arm 7 as shown, or a plurality of parallel loader arms 7 actuated simultaneously by the different jacks 11, 18, 26.
  • the different segments 7a, 7b constituting each arm loader 7 are mechanically connected to each other by crosspieces, and the deployment cylinder 18 is not disposed inside a loader arm 7, but on the contrary in the middle position between each of the loader arms 7.
  • the lifting structure 2 with telescopic arm is characterized in that it comprises a mechanical system 30, 31, 32, 33 of articulated connecting rods and levers making it possible to automatically keep the attitude of the tool 23 constant when modifications of the inclination of the loader arm 7 under the action of the lifting cylinder 11, and in that the discharge and deployment cylinders 26 and 18 are hydraulically connected so as to automatically maintain constant the attitude of the tool 23 during the deployment and retraction of the telescopic loader arm 7, while allowing, if necessary, the pivoting of this tool 23 about its axis 25 under the action of the discharge cylinder 26 in the direction of loading or discharge .
  • the discharge cylinder 26 is integrated into the mechanical system 30, 31, 32, 33.
  • the cylinder 34 of the discharge cylinder 26 is articulated and bears on a first member 31 of this mechanical system.
  • the actuating rod 29 of the discharge cylinder 26 is articulated to a second member 32 of this mechanical system.
  • this discharge cylinder 26 constitutes a connecting rod of variable length for this mechanical system, and connects said first member 31 and second member 32.
  • the discharge cylinder 26 has a double function: firstly it connects the two members 31, 32 of the mechanical system by allowing automatic compensation of the trim of the tool 33 when the inclination of the loader arm is modified; moreover, it makes it possible to pivot the tool 23 about its axis 25 when it is actuated.
  • the discharge cylinder 26, hydraulically linked to the deployment cylinder 18, sees its length automatically modified subsequently, due to its hydraulic connection. with the deployment cylinder 18. In this way, the trim of the tool 23 is also preserved during the deployment or retraction of the loader arm 7.
  • said first member 31 is associated with the first segment 7a of the loader arm 7
  • said second member 32 is associated with the structure 2 near the tool 23
  • the discharge cylinder 26 extends at least substantially parallel to the deployment cylinder 18, and the travel stroke of the discharge cylinder 26 corresponds to that of the deployment cylinder 18 increased by the travel necessary for the pivoting movements of the tool 23 in each extreme deployed and retracted position of the loader arm 7 and of the deployment cylinder 18.
  • the travel of travel of the two discharge cylinders 26 and deployment 18 are similar during the deployment and retraction maneuvers, and, in each extreme position, the pivoting of the tool 23 around of its axis 25 can be controlled by the discharge cylinder 26.
  • said first member 31 is a first lever 31 articulated to the first segment 7a of the loader arm 7 about a horizontal pivot axis 36.
  • This horizontal pivot axis 36 is mounted on the first segment 7a, in particular on its upper face 37.
  • the first lever 31 extends on either side from this pivot axis 36. It therefore comprises a first arm 38 which extends generally upwards from the pivot axis 36, and whose free end 39 is associated articulated with the cylinder 34 of the discharge cylinder 26 about a horizontal pivot axis 40.
  • this first lever 31 also includes a second arm 41 extending generally downward from the pivot axis 36 of the first lever on the first segment 7a of the loader arm 7.
  • Said first lever 31 is connected to the pivot axis 12 connecting the lifting cylinder 11 to the chassis 3 of the structure 2 by a first connecting rod 30 articulated to this first lever 31 by a 42 of the ends of this connecting rod 30 and to this pivot axis 12 by its other end 43.
  • the end 42 of the first connecting rod 30 associated articulated to the first lever 31 is articulated at the free end 44 of the second arm 41 of the first lever 31 about a horizontal pivot axis 45.
  • said second member 32 is a second lever articulated at the free end 24 of the loader arm 7 around a horizontal pivot axis 46.
  • This pivot axis 46 of the second lever 32 is located on the loader arm 7 slightly set back relative to the pivot axis 25 of the tool 23.
  • the second lever 32 extends generally upwards from its axis pivoting 46 relative to the loader arm 7.
  • the actuating rod 29 of the discharge cylinder 26 is articulated by its free end 28 in the middle part of the second lever 32 about a horizontal pivot axis 47.
  • the second lever 32 is connected to the tool 23, in particular via the adaptation mechanism 27, by means of a second connecting rod 33.
  • This second connecting rod 33 is articulated by a 48 of its ends at the free end 49 of the second lever 32 about a horizontal pivot axis 50. Furthermore, this second connecting rod 33 is also articulated by its other end 51 to the adaptation mechanism 27 of the tool 23 around a horizontal pivot axis 52. This horizontal pivot axis 52 is disposed substantially above the pivot axis 25 of the tool 23 and its adaptation mechanism 27 relative to the loader arm 7. Thus, the adaptation mechanism 27, and therefore the tool 23 is held and controlled in position relative to the pivot axis 25 by the discharge cylinder 26 via the second lever 32 and the second connecting rod 33.
  • the pivot axis 36 of the first lever 31 relative to the first segment 7a of the loader arm 7 is located substantially in the middle part of this first segment 7a.
  • the pivot axis 40 of the first lever 31 on the cylinder 34 of the discharge cylinder 26 is located substantially in the middle part of this cylinder 34.
  • the first connecting rod 30 extends generally at least substantially parallel to the cylinder lifting 11 between the pivot axis 12 which connects it to the chassis 3, and the pivot axis 45 which connects it to the first lever 31.
  • the lifting cylinder 11 and the first connecting rod 30 extend under the first segment 7a of the loader arm 7.
  • the discharge cylinder 26 extends above this first segment 7a, and the second lever 32 and the second connecting rod 33 extend above the free end 24 of the loader arm 7.
  • the first lever 31 extends substantially transversely to the first segment 7a to connect the first connecting rod 30 to the discharge cylinder 26.
  • the mechanical system 30, 31, 32, 33 can be simple, as described above, or split, like the loader arm 7. It is thus possible to provide two simple systems on either side of each loader arm 7, and of which the respective elements in correspondence are connected to each other transversely.
  • the mechanical connections to the pivot axis mentioned above can be made by any suitable known means: bearings, yokes, bearings, etc.
  • each of the deployment cylinders 18 and discharge 26 is a double-acting cylinder controlled from a valve 53, 54 double inlet / outlet distributor connected to the inlet chambers 55, 56 and outlet 57, 58 of this cylinder 18, 26 by a hydraulic control circuit 59, 60.
  • the discharge cylinder 26 is mounted in series in the control circuit 59 of the deployment cylinder 18, and the valve 54 of control of the discharge cylinder 26 is connected directly in parallel to the chambers 56, 58 of this discharge cylinder 26.
  • the mounting of the hydraulic circuits 59, 60 is illustrated in FIG. 5.
  • the inlet chamber 56 of the discharge cylinder 26 is directly connected by a conduit 61 to a first terminal 62 of the valve 54.
  • the outlet chamber 58 of this same discharge cylinder 26 is directly connected to the other terminal 63 of the valve 54 by another conduit 64.
  • the outlet chamber 57 of the deployment cylinder 18 is directly connected to a first terminal 65 of the valve 53 by a conduit 66.
  • the other terminal 67 of this valve 53 is connected by a conduit 68 to the conduit 61 connecting the inlet chamber 56 of the discharge cylinder 26 to the valve 54.
  • the inlet chamber 55 of the deployment cylinder 18 is connected by a line 69 to line 64 connecting the outlet chamber 58 of the discharge cylinder 26 to the valve 54.
  • the valves 53, 54 are designed such that when pressurized fluid passes through one 65, 63 of their terminal in one direction, the fluid passes through the other terminal 67, 62 in the other direction.
  • the two cylinders 26, 18 are mounted in series.
  • the outlet chamber 58 of the discharge cylinder 26 is connected by the conduits 64, 69 to the inlet chamber 55 of the deployment cylinder 18.
  • the two chambers 58, 55 respectively of the discharge cylinder 26 and the deployment cylinder 18 which are directly connected to one another, in particular by the conduits 64, 69, both have the same section.
  • the valve 54 distributing the discharge cylinder 26 is placed in the neutral position. In this case, the terminals 62, 63 of this valve are closed.
  • the hydraulic fluid is sent through terminal 65 of the valve 53 distributing the deployment cylinder 18, by the conduit 66 in the outlet chamber 57 of this cylinder 18.
  • the displacement of the piston 70 of this cylinder 18 discharges the hydraulic fluid from the inlet chamber 55 through the conduits 69, 64 connecting it to the outlet chamber 58 of the discharge cylinder 26.
  • the piston 71 of the discharge cylinder 26 is therefore also displaced and discharges the hydraulic fluid from the inlet chamber 56 via the conduits 61 and 68 to the terminal 67 of the valve 53 distributing the deployment cylinder 18.
  • valve 53 distributing the deployment cylinder 18 is placed in the neutral position, its terminals 65, 67 being closed.
  • the hydraulic fluid is sent by the distributor valve 54 to one or other of the inlet or outlet chambers 56, 58 of this jack 26 in order to actuate it in a conventional manner.
  • the cylinders which equip the lifting structure 2, and in particular the discharge cylinder 26 and the deployment cylinder 18 are provided with flow control valves 72 avoiding any shift between these cylinders which could occur due to the phenomena cavitation.
  • valves 53, 54 distributors can be controlled from the cockpit 5 from two control levers or even a single lever if these valves 53, 54 are coupled. They advantageously consist of solenoid valves.
  • the invention also relates to a self-propelled loader 1 characterized in that it is equipped with a lifting structure 2 according to the invention.
  • each loader arm 7 consists only of two telescopic segments 7a, 7b.
  • a larger number of segments risks making the lifting structure 2 insufficiently resistant for important work such as earthworks.
  • the lifting structure 2 according to the invention has been found to be of sufficient strength to be applied to a loader 1.
  • the invention can be used in other applications , in particular on other types of machinery of the public works type, self-propelled or not, when the same technical problems are encountered.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • General Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Operation Control Of Excavators (AREA)

Abstract

The invention relates to a lifting structure (2) comprising at least one telescopic loading arm (7) equipped with a tool (23) and actuated by a lifting jack (11), a deployment jack and a discharge jack (26), characterised in that it comprises a mechanical system (30, 31, 32, 33) of articulated connecting rods and levers, and in that the discharge (26) and deployment jacks are connected hydraulically, so as automatically to keep the attitude of the tool (23) constant during changes of position and length of the loading arm (7). The invention can be used on public works appliances, such as loaders or the like. <IMAGE>

Description

L'invention concerne une structure de levage télescopique pour un engin tel qu'une chargeuse automotrice.The invention relates to a telescopic lifting structure for a machine such as a self-propelled loader.

On connaît déjà de telles structures de levage commandées par des vérins hydrau­liques, constituées essentiellement d'au moins un bras chargeur télescopique (simple ou double) articulé au châssis de l'engin. Un outil tel qu'un godet, palettiseur, potence, lame de remblayage, balayeuse, benne, rateau andaineur ou autre est articulé à l'extrémité libre du bras chargeur. Le bras télescopique comprend au moins deux segments dont le premier est associé articulé à mais solidaire du châssis et dont l'autre coulisse à l'intérieur du premier sous l'action d'un vérin de déploiement disposé à l'intérieur du et prenant appui sur le premier segment. L'outil est articulé à l'extrémité libre du second segment coulissant et son assiette peut être réglée sous l'action d'un vérin de déversement prenant appui sur le second segment coulis­sant et dont la tige d'actionnement est reliée mécaniquement à l'outil. Par ailleurs, l'inclinaison du bras chargeur télescopique est réglable grâce à un vérin de levage prenant appui sur le châssis et relié mécaniquement au premier segment de ce bras.We already know such lifting structures controlled by hydraulic cylinders, essentially consisting of at least one telescopic loader arm (single or double) articulated to the chassis of the machine. A tool such as a bucket, palletizer, jib, backfill blade, sweeper, bucket, rake rake or other is articulated at the free end of the loader arm. The telescopic arm comprises at least two segments, the first of which is associated articulated with but integral with the chassis and the other of which slides inside the first under the action of a deployment cylinder disposed inside the and supported on the first segment. The tool is articulated at the free end of the second sliding segment and its attitude can be adjusted under the action of a tilting cylinder bearing on the second sliding segment and whose actuating rod is mechanically connected to the tool. Furthermore, the inclination of the telescopic loader arm is adjustable by means of a lifting cylinder bearing on the chassis and mechanically connected to the first segment of this arm.

Avec de telles structures de levage à bras télescopique, le problème général qui se pose est celui de la correction automatique de l'assiette de l'outil lors de la modification de l'inclinaison du bras chargeur. En effet, il est nécessaire que l'assiette de l'outil soit conservée lors de cette modification d'inclinaison pour permettre une utilisation correcte de la chargeuse.With such lifting structures with telescopic arms, the general problem which arises is that of the automatic correction of the attitude of the tool when the inclination of the loader arm is modified. Indeed, it is necessary that the trim of the tool is kept during this modification of inclination to allow correct use of the loader.

Dans les structures de levage non télescopiques à bras chargeur de longueur fixe, cette correction automatique de l'assiette est obtenue grâce à un système mécanique à bielles et leviers articulés, le vérin de déversement étant relié à l'un de ces leviers ou bielles. Dans une première variante connue, seule la tige d'actionnement du vérin de déversement est reliée à un levier du système mécanique, le cylindre de ce vérin étant solidaire du châsis. Dans une autre variante connue, le vérin de déversement est intégré au système mécanique dans lequel il remplace une bielle, son cylindre étant articulé à un levier, et sa tige d'actionnement coopérant avec un autre levier relié à l'outil ou avec l'outil lui-même. Ces solutions purement mécaniques ne sont pas directement transposables au cas d'un bras télescopique dont la longueur est variable.In non-telescopic lifting structures with fixed-length loader arms, this automatic correction of the attitude is obtained thanks to a mechanical system with connecting rods and articulated levers, the discharge cylinder being connected to one of these levers or connecting rods. In a first known variant, only the actuating rod of the discharge cylinder is connected to a lever of the mechanical system, the cylinder of this cylinder being integral with the frame. In another known variant, the discharge cylinder is integrated into the mechanical system in which it replaces a connecting rod, its cylinder being articulated to a lever, and its actuating rod cooperating with another lever connected to the tool or with the tool itself. These purely mechanical solutions cannot be directly transposed to the case of a telescopic arm whose length is variable.

C'est pourquoi, dans les structures de levage à bras télescopique connues, on assure généralement la correction de l'assiette de l'outil grâce à une liaison purement hydraulique entre le vérin de levage et le vérin de déversement.This is why, in lifting structures with known telescopic arms, it is generally ensured that the attitude of the tool is corrected by means of a purely hydraulic connection between the lifting cylinder and the discharge cylinder.

Dans une première variante connue, la chambre de sortie du vérin de levage est directement reliée à la chambre d'entrée du vérin de déversement placé à l'extrémité du second segment coulissant. Dans ce cas, le volume de fluide déplacé dans la chambre de sortie du vérin de levage est intégralement transmis, par la liaison hydraulique, à la chambre d'entrée du vérin de déversement. Néanmoins, une telle solution impose des contraintes sur les cylindrées et les fixations respectives de ces deux vérins pour assurer la correction d'assiette, qu'il n'est pas toujours possible de satisfaire compte tenu des impératifs mécaniques et des différences de taille et de puissance qu'il est souhaitable de respecter entre ces deux vérins. En particulier, le vérin de levage doit généralement développer une force plus grande que le vérin de déversement.In a first known variant, the outlet chamber of the lifting cylinder is directly connected to the inlet chamber of the discharge cylinder placed at the end of the second sliding segment. In this case, the volume of fluid displaced in the outlet chamber of the lifting cylinder is fully transmitted, by the hydraulic connection, to the inlet chamber of the discharge cylinder. However, such a solution imposes constraints on the displacements and the respective fastenings of these two jacks to ensure the correction of attitude, which it is not always possible to satisfy taking into account the mechanical requirements and the differences in size and power that it is desirable to respect between these two cylinders. In particular, the lifting cylinder generally has to develop a greater force than the dumping cylinder.

C'est pourquoi, dans une deuxième variante connue, on prévoit un quatrième vérin doseur placé parallèlement au vérin de levage, mais dimensionné de façon similaire au vérin de déversement auquel il est relié hydrauliquement de la même façon que le vérin de levage dans la première variante susmentionnée. Le vérin doseur suit alors le vérin de levage dans le mouvement d'inclinaison et le volume de fluide déplacé dans sa chambre de sortie est intégralement transmis à la chambre d'entrée du vérin de déversement qui est ainsi automatiquement commandé. Cette deuxième solution présente néanmoins l'inconvénient de nécessiter un vérin supplémentaire ce qui augmente le coût final de la structure. De plus, il n'est pas toujours possible, pour des questions d'encombrement, d'intégrer un tel vérin doseur à la structure ni de relier directement le vérin de levage au vérin de déversement compte tenu de leurs caractéristiques respectives. Ainsi, il n'est pas toujours possible d'effectuer une correction d'assiette parfaitement proportionnelle sur toute la course de levage du bras chargeur.This is why, in a second known variant, there is provided a fourth metering cylinder placed parallel to the lifting cylinder, but dimensioned similarly to the dumping cylinder to which it is hydraulically connected in the same way as the lifting cylinder in the first. aforementioned variant. The metering cylinder then follows the lifting cylinder in the tilting movement and the volume of fluid displaced in its outlet chamber is fully transmitted to the inlet chamber of the discharge cylinder which is thus automatically controlled. This second solution nevertheless has the disadvantage of requiring an additional cylinder which increases the final cost of the structure. In addition, it is not always possible, for reasons of space, to integrate such a metering cylinder to the structure or to directly connect the lifting cylinder to the discharge cylinder taking into account their respective characteristics. Thus, it is not always possible to carry out a perfectly proportional attitude correction over the entire lifting stroke of the loader arm.

Par ailleurs, dans les structures de levage à bras télescopiques connues, la présence du vérin de déversement en tête du bras chargeur impose de dimensionner en consé­quence le bras chargeur télescopique, ce qui a pour conséquence d'alourdir la struc­ture et d'en augmenter le prix de revient. Egalement, les conduites de liaison exté­rieures entre les deux vérins sont soumises aux intempéries et aux chocs et usures, notamment du fait qu'elles se prolongent au voisinage immédiat de l'outil. De plus, la compensation hydraulique n'est pas jugée suffisamment résistante pour des travaux importants tels que le terrassement.Furthermore, in lifting structures with known telescopic arms, the presence of the discharge cylinder at the head of the loader arm means that the telescopic loader arm must be dimensioned accordingly, which has the consequence of making the structure heavier and increasing its cost price. Also, the external connecting pipes between the two cylinders are subjected to bad weather and to shocks and wear, in particular because they extend in the immediate vicinity of the tool. In addition, hydraulic compensation is not considered to be strong enough for important works such as earthworks.

La présente invention vise à remédier à ces inconvénients et a pour objet de proposer une structure de levage à bras télescopique :
- avec laquelle la correction d'assiette de l'outil est effectuée automa­tiquement de façon proportionnelle sur toute la course de levage et ce de façon simple et économique.
- les différents vérins, le bras chargeur et la motorisation ne sont dimen­sionnés qu'en fonction des contraintes mécaniques, et donc indépendamment des impératifs de la correction d'assiette de l'outil
- qui ne nécessite pas la présence d'un vérin doseur supplémentaire
- dont le vérin de déversement n'est pas placé en tête du bras chargeur, mais au contraire le plus près possible de l'articulation de ce bras au châssis
- qui ne présente pas des conduites de liaison hydrauliques au voisinage de l'outil.
- qui est d'une résistance et d'une fiabilité suffisante notamment équivalente à celle des structures non télescopiques, pour assurer des travaux impor­tants tels que le terrassement.The present invention aims to remedy these drawbacks and aims to propose a lifting structure with a telescopic arm:
- with which the adjustment of the attitude of the tool is carried out automatically in a proportional manner over the entire lifting stroke and this in a simple and economical manner.
- the different cylinders, the loader arm and the motorization are only dimensioned as a function of mechanical constraints, and therefore independently of the requirements for correcting the attitude of the tool
- which does not require the presence of an additional metering cylinder
- whose discharge cylinder is not placed at the head of the loader arm, but on the contrary as close as possible to the articulation of this arm to the chassis
- which does not have hydraulic connection lines in the vicinity of the tool.
- which is of sufficient strength and reliability, in particular equivalent to that of non-telescopic structures, to ensure important work such as earthworks.

Plus généralement, la présente invention vise à proposer une telle structure de levage dont les rapports performances sur poids et performances sur coûts (prix de revient et coûts d'utilisation) soient plus élevés que ceux des structures connues.More generally, the present invention aims to propose such a lifting structure whose performance-to-weight and performance-to-cost ratios (cost price and operating costs) are higher than those of known structures.

Pour ce faire, l'invention propose une structure de levage pour un engin tel qu'une chargeuse comprenant au moins un bras chargeur télescopique constitué d'au moins deux segments dont le premier est articulé par une de ses extrémités au châssis de l'engin de façon à pouvoir pivoter au moins dans un plan vertical autour d'un axe de pivotement horizontal sous l'action d'un vérin de levage, et dont le second coulisse selon un axe de déploiement/rétraction par rapport au premier sous l'action d'un vérin de déploiement, la structure comprenant aussi un outil associé articulé à l'extrémité libre du bras chargeur de façon à pouvoir pivoter au moins dans ledit plan vertical autour d'un axe de pivotement horizontal sous l'action d'un vérin de déversement, caractérisée en ce qu'elle comporte un système mécanique de bielles et leviers articulés permettant de maintenir automatiquement constante l'assiette de l'outil lors des modifications de l'inclinaison du bras chargeur, et en ce que les vérins de déversement et de déploiement sont liés hydrauliquement de façon à maintenir automatiquement constante l'assiette de l'outil lors du déploiement et lors de la rétraction du bras chargeur, tout en permettant, en cas de besoin, le pivotement de l'outil sous l'action du vérin de déversement. Le vérin de déver­sement est intégré au système mécanique, son cylindre étant articulé et prenant appui sur un premier organe de ce système mécanique, sa tige d'actionnement étant articulée à un deuxième organe du système mécanique, de sorte que ce vérin constitue une bielle de longueur variable pour ce système mécanique. Le premier organe est associé au premier segment du bras chargeur, le deuxième organe est associé à la structure à proximité de l'outil, le vérin de déversement s'étend au moins sensiblement parallèlement au vérin de déploiement, et la course de débatte­ment du vérin de déversement correspond à celle du vérin de déploiement augmentée de la course nécessaire aux mouvements de pivotement de l'outil dans chaque position extrême déployée et rétractée du bras chargeur et du vérin de déploiement.To do this, the invention provides a lifting structure for a machine such as a loader comprising at least one telescopic loader arm consisting of at least two segments, the first of which is articulated by one of its ends to the chassis of the machine. so as to be able to pivot at least in a vertical plane around a horizontal pivot axis under the action of a lifting cylinder, and the second of which slides along an axis of deployment / retraction relative to the first under the action a deployment cylinder, the structure also comprising an associated tool articulated at the free end of the loader arm so as to be able to pivot at least in said vertical plane around a horizontal pivot axis under the action of a cylinder discharge, characterized in that it comprises a mechanical system of articulated connecting rods and levers making it possible to automatically maintain constant the attitude of the tool during modifications of the inclination of the load arm r, and in that the discharge and deployment jacks are hydraulically connected so as to automatically maintain constant the attitude of the tool during deployment and during the retraction of the loader arm, while allowing, if necessary, the pivoting of the tool under the action of the discharge cylinder. The discharge cylinder is integrated into the mechanical system, its cylinder being articulated and bearing on a first member of this mechanical system, its actuating rod being articulated to a second member of the mechanical system, so that this cylinder constitutes a connecting rod variable length for this mechanical system. The first member is associated with the first segment of the loader arm, the second member is associated with the structure near the tool, the discharge cylinder extends at least substantially parallel to the deployment cylinder, and the cylinder travel stroke discharge corresponds to that of the deployment cylinder increased by the stroke necessary for the pivoting movements of the tool in each extreme deployed and retracted position of the loader arm and of the deployment cylinder.

Ledit premier organe est un premier levier articulé au premier segment autour d'un axe de pivotement horizontal, et ledit deuxième organe est un deuxième levier articulé à l'extrémité libre du bras chargeur autour d'un axe de pivotement horizontal. Le premier levier est relié à l'axe de pivotement reliant le vérin de levage au châssis de la structure par une première bielle articulée à ce premier levier et à cet axe. Le deuxième levier est relié à l'outil grâce à une deuxième bielle articulée à ce deuxième levier et à cet outil.Said first member is a first lever articulated at the first segment around a horizontal pivot axis, and said second member is a second lever articulated at the free end of the loader arm around a horizontal pivot axis. The first lever is connected to the pivot axis connecting the lifting cylinder to the frame of the structure by a first connecting rod articulated to this first lever and to this axis. The second lever is connected to the tool by means of a second link articulated to this second lever and to this tool.

Selon l'invention, chacun des vérins de déploiement et de déversement est un vérin à double effet commandé à partir d'une vanne double d'entrée/sortie reliée aux chambres d'entrée et de sortie de ce vérin par un circuit de commande ; le vérin de déversement est monté en série dans le circuit de commande du vérin de dé­ploiement ; et la vanne de commande du vérin de déversement est reliée directement en parallèle aux chambres de ce vérin. Les deux chambres respectivement du vérin de déversement et du vérin de redéploiement qui sont directement reliées l'une à l'autre, ont toutes deux la même section. Le vérin de déversement et le vérin de déploiement sont munis de valves régulatrices de débit évitant tout décalage entre ces vérins, qui serait dû par exemple aux phénomènes de cavitation.According to the invention, each of the deployment and discharge cylinders is a double-acting cylinder controlled from a double inlet / outlet valve connected to the inlet and outlet chambers of this jack by a control circuit; the discharge cylinder is mounted in series in the control circuit of the deployment cylinder; and the control valve of the discharge cylinder is connected directly in parallel to the chambers of this cylinder. The two chambers respectively of the discharge cylinder and the redeployment cylinder which are directly connected to each other, both have the same section. The discharge cylinder and the deployment cylinder are provided with flow regulating valves avoiding any offset between these cylinders, which would be due for example to cavitation phenomena.

Ainsi, selon l'invention, la compensation automatique de l'assiette de l'outil est effectuée mécaniquement par le système mécanique lors des modifications de l'incli­naison du bras chargeur, et hydrauliquement par les liaisons hydrauliques entre le vérin de déversement et le vérin de déploiement lors des modifications de la longueur du bras chargeur télescopique. De la sorte, l'invention fournit une solution avantageuse simultanément aux divers objets mentionnés ci-dessus.Thus, according to the invention, the automatic compensation of the trim of the tool is carried out mechanically by the mechanical system during modifications of the inclination of the loader arm, and hydraulically by the hydraulic connections between the discharge cylinder and the cylinder deployment when changing the length of the telescopic loader arm. In this way, the invention provides an advantageous solution simultaneously to the various objects mentioned above.

L'invention concerne aussi une chargeuse automotrice caractérisée en ce qu'elle est équipée d'une structure de levage selon l'invention.The invention also relates to a self-propelled loader characterized in that it is equipped with a lifting structure according to the invention.

D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description suivante qui se réfère aux figures annexées représentant un mode de réalisation préférentielle de l'invention à titre d'exemple, et dans lesquelles :

  • - les figures 1 à 3 sont des vues schématiques en élévation d'une chargeuse équipée d'une structure de levage selon l'invention, respectivement en position élevée, abaissée, et intermédiaire, et équipée d'une fourche de palettisation. Sur la figure 1, la position de l'outil lorsque le bras chargeur est rétracté a été représentée en traits pointillés. Sur la figure 3, la position de l'outil lorsque le bras chargeur est déployé a été repré­sentée en traits pointillés. Sur ces figures, les parties cachées illustratives de l'invention ont été représentées en traits pleins pour plus de clarté.
  • - la figure 4 est une vue en coupe verticale d'une chargeuse équipée d'une structure de levage selon l'invention, en position abaissée, et équipée d'un godet.
  • - la figure 5 est un diagramme illustrant schématiquement les circuits hydrauliques de commande du vérin de déversement et du vérin de dé­ploiement d'une structure de levage selon l'invention.
Other characteristics and advantages of the invention will appear on reading the following description which refers to the appended figures representing a preferred embodiment of the invention by way of example, and in which:
  • - Figures 1 to 3 are schematic elevational views of a loader equipped with a lifting structure according to the invention, respectively in the raised, lowered, and intermediate position, and equipped with a palletizing fork. In FIG. 1, the position of the tool when the loader arm is retracted has been shown in dotted lines. In FIG. 3, the position of the tool when the loader arm is deployed has been shown in dotted lines. In these figures, the illustrative hidden parts of the invention have been shown in solid lines for greater clarity.
  • - Figure 4 is a vertical sectional view of a loader equipped with a lifting structure according to the invention, in the lowered position, and equipped with a bucket.
  • - Figure 5 is a diagram schematically illustrating the hydraulic circuits for controlling the discharge cylinder and the deployment cylinder of a lifting structure according to the invention.

Sur les figures, on a représenté une chargeuse 1 automotrice équipée d'une structure de levage à bras télescopique selon l'invention. Une telle chargeuse 1 comporte un châssis 3 -notamment en plusieurs parties articulées- supportant une pluralité d'essieux et de roues ou chenilles 4, un poste ou une cabine de pilotage 5, et un groupe motopropulseur 6 susceptible de fournir un fluide de commande sous pression -notamment de l'huile- à destination des différents vérins permettant le fonction­nement de la structure de levage 2.The figures show a self-propelled loader 1 equipped with a lifting structure with telescopic arm according to the invention. Such a loader 1 comprises a chassis 3 - in particular in several articulated parts - supporting a plurality of axles and wheels or tracks 4, a station or a cockpit 5, and a powertrain 6 capable of supplying a control fluid under pressure - in particular oil - intended for the different cylinders allowing the functioning of the lifting structure 2.

La structure de levage 2 selon l'invention comprend au moins un bras chargeur 7 télescopique constitué d'au moins deux segments 7a, 7b dont le premier 7a est articulé par une 8 de ses extrémités 8, 9 au châssis 3 de l'engin 1 de façon à pouvoir pivoter au moins dans un plan vertical autour d'un axe de pivotement 10 horizontal sous l'action d'un vérin de levage 11. Ce vérin de levage 11 est articulé par son cylindre 13 au châssis 3 autour d'un axe de pivotement 12 horizontal situé à distance de et à un niveau plus inférieur que l'axe de pivotement 10 horizontal reliant le premier segment 7a au châssis 3. L'extrémité libre 14 de la tige d'actionnement 15 du vérin de levage 11 est par ailleurs articulée sous le premier segment 7a autour d'un axe de pivotement 16 horizontal.The lifting structure 2 according to the invention comprises at least one telescopic loader arm 7 consisting of at least two segments 7a, 7b of which the first 7a is articulated by an 8 of its ends 8, 9 to the chassis 3 of the machine 1 so as to be able to pivot at least in a vertical plane around a horizontal pivot axis 10 under the action of a lifting cylinder 11. This lifting cylinder 11 is articulated by its cylinder 13 to the chassis 3 around a horizontal pivot axis 12 located at a distance from and at a level lower than the horizontal pivot axis 10 connecting the first segment 7a to the chassis 3. The free end 14 of the actuating rod 15 of the lifting cylinder 11 is also articulated under the first segment 7a about a horizontal pivot axis 16.

Le second segment 7b du bras chargeur 7 coulisse selon un axe de déploiement/rétrac­tion 17 par rapport au premier segment 7a sous l'action d'un vérin de déploiement 18. L'axe de déploiement/rétraction 17 est perpendiculaire à l'axe de pivotement 10 horizontal d'association du premier segment 7a au châssis 3. Le cylindre 19 de ce vérin de déploiement 18 est associé rigidement au et prend appui sur le fond du premier segment 7a du bras chargeur 7. La tige d'actionnement 21 du vérin de déploiement 18 est associée rigidement à une membrure 22 interne du second segment 7b. Le vérin de déploiement 18 est donc disposé à l'intérieur du premier segment 7a qui est creux et commande le second segment 7b, également creux, dans son coulissement en vue du déploiement ou de la rétraction du bras chargeur 7 télescopique. Le second segment 7b pénètre dans le premier segment 7a par l'extrémité libre creuse de ce premier segment 7a. Les sections droites transversales de ces segments sont en correspondance pour permettre leur coulissement l'un par rapport à l'autre. Des organes de guidage appropriés, connus en eux- mêmes, sont aussi prévus pour faciliter ce coulissement.The second segment 7b of the loader arm 7 slides along a deployment / retraction axis 17 relative to the first segment 7a under the action of a deployment cylinder 18. The deployment / retraction axis 17 is perpendicular to the axis of horizontal pivoting 10 for associating the first segment 7a with the chassis 3. The cylinder 19 of this deployment cylinder 18 is rigidly associated with and bears on the bottom of the first segment 7a of the loader arm 7. The actuating rod 21 of the cylinder deployment 18 is rigidly associated with an internal frame 22 of the second segment 7b. The deployment cylinder 18 is therefore placed inside the first segment 7a which is hollow and controls the second segment 7b, also hollow, in its sliding for the deployment or retraction of the telescopic loader arm 7. The second segment 7b enters the first segment 7a through the hollow free end of this first segment 7a. The cross sections of these segments are in correspondence to allow them to slide relative to each other. Appropriate guide members, known in themselves, are also provided to facilitate this sliding.

La structure de levage 2 selon l'invention comprend aussi un outil 23 associé articulé à l'extrémité libre 24 du bras chargeur 7 de façon à pouvoir pivoter au moins dans ledit plan vertical autour d'un axe de pivotement 25 horizontal sous l'action d'un vérin de déversement 26. Dans le mode de réalisation représenté où le bras chargeur 7 est composé uniquement de deux segments 7a, 7b, l'extrémité libre 24 du bras chargeur 7 à laquelle l'outil 23 est articulé est aussi l'extrémité libre du second segment 7b. L'outil 23 peut être constitué d'un godet, d'une fourche de palettisation, d'une potence, d'une lame de remblayage, d'une balayeuse, d'une benne, d'un rateau andaineur, ou autre. Sur les figures 1 à 3 l'outil 23 a été représenté sous forme d'une fourche de palettisation. Sur la figure 4, l'outil 23 représenté est un godet. L'outil 23 est articulé à l'extrémité libre 24 du bras chargeur 7 par l'intermédiaire d'un mécanisme d'adaptation rapide 27 connu en soi, permettant d'interchanger l'outil 23. Par ailleurs, l'outil 23 est relié à l'extrémité libre 28 de la tige d'action­nement 29 du vérin de déversement 26, notamment par l'intermédiaire d'une bielle 33, d'un levier 32, et du mécanisme d'adaptation 27.The lifting structure 2 according to the invention also comprises an associated tool 23 articulated at the free end 24 of the loader arm 7 so as to be able to pivot at least in said vertical plane around a horizontal pivot axis 25 under the action a discharge cylinder 26. In the embodiment shown where the loader arm 7 is composed only of two segments 7a, 7b, the free end 24 of the loader arm 7 to which the tool 23 is articulated is also the free end of the second segment 7b. The tool 23 may consist of a bucket, a palletizing fork, a jib, a backfill blade, a sweeper, a bucket, a swather rake, or the like. In Figures 1 to 3 the tool 23 has been shown in the form of a palletizing fork. In Figure 4, the tool 23 shown is a bucket. The tool 23 is articulated at the free end 24 of the loader arm 7 by means of a rapid adaptation mechanism 27 known per se, making it possible to interchange the tool 23. Furthermore, the tool 23 is connected to the free end 28 of the actuating rod 29 of the discharge cylinder 26, in particular by means of a connecting rod 33, a lever 32, and the adaptation mechanism 27.

Le vérin de levage 11 est un vérin à double effet et permet de modifier l'inclinaison du bras chargeur 7 par rapport à l'horizontal, dans le sens du levage ou dans celui de l'abaissement. Le vérin de déploiement 18 est un vérin à double effet, et permet la modification de la longueur du bras chargeur 7 télescopique dans le sens du dé­ploiement ou dans celui de la rétraction. Le vérin de déversement 26 est un vérin à double effet, et permet de faire pivoter l'outil 23 autour de son axe de pivotement 25 horizontal dans le sens du déversement, ou dans celui du chargement. Les vérins 11, 18, 26 de levage, déploiement et déversement permettent aussi le maintien de la structure de levage 2 dans une position déterminée.The lifting cylinder 11 is a double-acting cylinder and makes it possible to modify the inclination of the loader arm 7 relative to the horizontal, in the direction of lifting or in that of lowering. The deployment cylinder 18 is a double-acting cylinder, and allows the modification of the length of the telescopic loader arm 7 in the direction of deployment or in that of retraction. The discharge cylinder 26 is a double-acting cylinder, and makes it possible to pivot the tool 23 about its horizontal pivot axis 25 in the direction of the discharge, or in that of the loading. The cylinders 11, 18, 26 lifting, deployment and dumping also allow the maintenance of the lifting structure 2 in a determined position.

La structure de levage 2 peut comprendre un seul bras chargeur 7 télescopique comme représenté, ou une pluralité de bras chargeurs 7 parallèles actionnés simul­tanément par les différents vérins 11, 18, 26. Dans ce dernier cas, les différents segments 7a, 7b constituant chaque bras chargeur 7 sont reliés mécaniquement les uns aux autres par des traverses, et le vérin de déploiement 18 n'est pas disposé à l'intérieur d'un bras chargeur 7, mais au contraire en position médiane entre chacun des bras chargeurs 7. Par exemple, on peut prévoir deux bras chargeurs 7 disposés symétriquement de part et d'autre d'un plan vertical longitudinal de symétrie de l'engin 1.The lifting structure 2 can comprise a single telescopic loader arm 7 as shown, or a plurality of parallel loader arms 7 actuated simultaneously by the different jacks 11, 18, 26. In the latter case, the different segments 7a, 7b constituting each arm loader 7 are mechanically connected to each other by crosspieces, and the deployment cylinder 18 is not disposed inside a loader arm 7, but on the contrary in the middle position between each of the loader arms 7. For example , it is possible to provide two loading arms 7 arranged symmetrically on either side of a longitudinal vertical plane of symmetry of the machine 1.

Selon l'invention, la structure de levage 2 à bras télescopique est caractérisée en ce qu'elle comporte un système mécanique 30, 31, 32, 33 de bielles et leviers articulés permettant de maintenir automatiquement constante l'assiette de l'outil 23 lors des modifications de l'inclinaison du bras chargeur 7 sous l'action du vérin de levage 11, et en ce que les vérins de déversement 26 et de déploiement 18 sont liés hydrauliquement de façon à maintenir automatiquement constante l'assiette de l'outil 23 lors du déploiement et de la rétraction du bras chargeur 7 télescopique, tout en permettant, en cas de besoin, le pivotement de cet outil 23 autour de son axe 25 sous l'action du vérin de déversement 26 dans le sens du chargement ou du déversement.According to the invention, the lifting structure 2 with telescopic arm is characterized in that it comprises a mechanical system 30, 31, 32, 33 of articulated connecting rods and levers making it possible to automatically keep the attitude of the tool 23 constant when modifications of the inclination of the loader arm 7 under the action of the lifting cylinder 11, and in that the discharge and deployment cylinders 26 and 18 are hydraulically connected so as to automatically maintain constant the attitude of the tool 23 during the deployment and retraction of the telescopic loader arm 7, while allowing, if necessary, the pivoting of this tool 23 about its axis 25 under the action of the discharge cylinder 26 in the direction of loading or discharge .

Selon l'invention, le vérin de déversement 26 est intégré au système mécanique 30, 31, 32, 33. Le cylindre 34 du vérin de déversement 26 est articulé et prend appui sur un premier organe 31 de ce système mécanique. La tige d'actionnement 29 du vérin de déversement 26 est articulée à un deuxième organe 32 de ce système mécanique. De la sorte, ce vérin de déversement 26 constitue une bielle de longueur variable pour ce système mécanique, et relie lesdits premier organe 31 et deuxième organe 32. Lorsque le vérin de déploiement 18 est inactif et que la longueur du bras chargeur 7 télescopique reste constante, le vérin de déversement 26 a une double fonction : tout d'abord il relie les deux organes 31, 32 du système mécanique en permettant la compensation automatique de l'assiette de l'outil 33 lors de la modification de l'inclinaison du bras chargeur ; par ailleurs, il permet de faire pivoter l'outil 23 autour de son axe 25 lorsqu'il est actionné. De plus, lorsque le vérin de déploiement 18 est actionné et que la longueur du bras chargeur 7 téles­copique est modifiée, le vérin de déversement 26, lié hydrauliquement au vérin de déploiement 18, voit sa longueur automatiquement modifiée subséquemment, du fait de sa liaison hydraulique avec le vérin de déploiement 18. De la sorte, l'assiette de l'outil 23 est également conservée lors du déploiement ou de la rétraction du bras chargeur 7.According to the invention, the discharge cylinder 26 is integrated into the mechanical system 30, 31, 32, 33. The cylinder 34 of the discharge cylinder 26 is articulated and bears on a first member 31 of this mechanical system. The actuating rod 29 of the discharge cylinder 26 is articulated to a second member 32 of this mechanical system. In this way, this discharge cylinder 26 constitutes a connecting rod of variable length for this mechanical system, and connects said first member 31 and second member 32. When the deployment cylinder 18 is inactive and the length of the telescopic loader arm 7 remains constant , the discharge cylinder 26 has a double function: firstly it connects the two members 31, 32 of the mechanical system by allowing automatic compensation of the trim of the tool 33 when the inclination of the loader arm is modified; moreover, it makes it possible to pivot the tool 23 about its axis 25 when it is actuated. In addition, when the deployment cylinder 18 is actuated and the length of the telescopic loader arm 7 is modified, the discharge cylinder 26, hydraulically linked to the deployment cylinder 18, sees its length automatically modified subsequently, due to its hydraulic connection. with the deployment cylinder 18. In this way, the trim of the tool 23 is also preserved during the deployment or retraction of the loader arm 7.

Selon l'invention, ledit premier organe 31 est associé au premier segment 7a du bras chargeur 7, ledit deuxième organe 32 est associé à la structure 2 à proximité de l'outil 23, le vérin de déversement 26 s'étend au moins sensiblement parallèlement au vérin de déploiement 18, et la course de débattement du vérin de déversement 26 correspond à celle du vérin de déploiement 18 augmentée de la course nécessaire aux mouvements de pivotement de l'outil 23 dans chaque position extrême déployée et rétractée du bras chargeur 7 et du vérin de déploiement 18. De la sorte, les courses de débattement des deux vérins de déversement 26 et de déploiement 18 sont similaires lors des manoeuvres de déploiement et de rétraction, et, dans chaque position extrême, le pivotement de l'outil 23 autour de son axe 25 peut être com­mandé par le vérin de déversement 26.According to the invention, said first member 31 is associated with the first segment 7a of the loader arm 7, said second member 32 is associated with the structure 2 near the tool 23, the discharge cylinder 26 extends at least substantially parallel to the deployment cylinder 18, and the travel stroke of the discharge cylinder 26 corresponds to that of the deployment cylinder 18 increased by the travel necessary for the pivoting movements of the tool 23 in each extreme deployed and retracted position of the loader arm 7 and of the deployment cylinder 18. In this way, the travel of travel of the two discharge cylinders 26 and deployment 18 are similar during the deployment and retraction maneuvers, and, in each extreme position, the pivoting of the tool 23 around of its axis 25 can be controlled by the discharge cylinder 26.

Selon l'invention, ledit premier organe 31 est un premier levier 31 articulé au premier segment 7a du bras chargeur 7 autour d'un axe de pivotement 36 horizontal. Cet axe de pivotement 36 horizontal est monté sur le premier segment 7a, notamment sur sa face supérieure 37. Le premier levier 31 s'étend de part et d'autre à partir de cet axe de pivotement 36. Il comporte donc un premier bras 38 qui s'étend globa­lement vers le haut à partir de l'axe de pivotement 36, et dont l'extrémité libre 39 est associée articulée au cylindre 34 du vérin de déversement 26 autour d'un axe de pivotement 40 horizontal. Par ailleurs, ce premier levier 31 comporte également un second bras 41 s'étendant globalement vers le bas à partir de l'axe de pivotement 36 du premier levier sur le premier segment 7a du bras chargeur 7. Ledit premier levier 31 est relié à l'axe de pivotement 12 reliant le vérin de levage 11 au châssis 3 de la structure 2 par une première bielle 30 articulée à ce premier levier 31 par une 42 des extrémités de cette bielle 30 et à cet axe de pivotement 12 par son autre extrémité 43. L'extrémité 42 de la première bielle 30 associée articulée au premier levier 31 est articulée à l'extrémité libre 44 du second bras 41 du premier levier 31 autour d'un axe de pivotement 45 horizontal.According to the invention, said first member 31 is a first lever 31 articulated to the first segment 7a of the loader arm 7 about a horizontal pivot axis 36. This horizontal pivot axis 36 is mounted on the first segment 7a, in particular on its upper face 37. The first lever 31 extends on either side from this pivot axis 36. It therefore comprises a first arm 38 which extends generally upwards from the pivot axis 36, and whose free end 39 is associated articulated with the cylinder 34 of the discharge cylinder 26 about a horizontal pivot axis 40. Furthermore, this first lever 31 also includes a second arm 41 extending generally downward from the pivot axis 36 of the first lever on the first segment 7a of the loader arm 7. Said first lever 31 is connected to the pivot axis 12 connecting the lifting cylinder 11 to the chassis 3 of the structure 2 by a first connecting rod 30 articulated to this first lever 31 by a 42 of the ends of this connecting rod 30 and to this pivot axis 12 by its other end 43. The end 42 of the first connecting rod 30 associated articulated to the first lever 31 is articulated at the free end 44 of the second arm 41 of the first lever 31 about a horizontal pivot axis 45.

Selon l'invention, ledit deuxième organe 32 est un deuxième levier articulé à l'extré­mité libre 24 du bras chargeur 7 autour d'un axe de pivotement 46 horizontal. Cet axe de pivotement 46 du deuxième levier 32 est situé sur le bras chargeur 7 légèrement en retrait par rapport à l'axe de pivotement 25 de l'outil 23. Le deu­xième levier 32 s'étend globalement vers le haut à partir de son axe de pivotement 46 par rapport au bras chargeur 7. La tige d'actionnement 29 du vérin de déversement 26 est articulée par son extrémité libre 28 en partie médiane du deuxième levier 32 autour d'un axe de pivotement 47 horizontal. Le deuxième levier 32 est relié à l'outil 23, notamment via le mécanisme d'adaptation 27, grâce à une deuxième bielle 33. Cette deuxième bielle 33 est articulée par une 48 de ses extrémités à l'extrémité libre 49 du deuxième levier 32 autour d'un axe de pivotement 50 horizontal. Par ailleurs, cette deuxième bielle 33 est également articulée par son autre extrémité 51 au mécanisme d'adaptation 27 de l'outil 23 autour d'un axe de pivotement 52 horizontal. Cet axe de pivotement 52 horizontal est disposé sensi­blement au-dessus de l'axe de pivotement 25 de l'outil 23 et de son mécanisme d'adaptation 27 par rapport au bras chargeur 7. Ainsi, le mécanisme d'adaptation 27, et donc l'outil 23, sont maintenus et commandés en position par rapport à l'axe de pivotement 25 par le vérin de déversement 26 via le deuxième levier 32 et la deuxième bielle 33.According to the invention, said second member 32 is a second lever articulated at the free end 24 of the loader arm 7 around a horizontal pivot axis 46. This pivot axis 46 of the second lever 32 is located on the loader arm 7 slightly set back relative to the pivot axis 25 of the tool 23. The second lever 32 extends generally upwards from its axis pivoting 46 relative to the loader arm 7. The actuating rod 29 of the discharge cylinder 26 is articulated by its free end 28 in the middle part of the second lever 32 about a horizontal pivot axis 47. The second lever 32 is connected to the tool 23, in particular via the adaptation mechanism 27, by means of a second connecting rod 33. This second connecting rod 33 is articulated by a 48 of its ends at the free end 49 of the second lever 32 about a horizontal pivot axis 50. Furthermore, this second connecting rod 33 is also articulated by its other end 51 to the adaptation mechanism 27 of the tool 23 around a horizontal pivot axis 52. This horizontal pivot axis 52 is disposed substantially above the pivot axis 25 of the tool 23 and its adaptation mechanism 27 relative to the loader arm 7. Thus, the adaptation mechanism 27, and therefore the tool 23 is held and controlled in position relative to the pivot axis 25 by the discharge cylinder 26 via the second lever 32 and the second connecting rod 33.

L'axe de pivotement 36 du premier levier 31 par rapport au premier segment 7a du bras chargeur 7 est situé sensiblement en partie médiane de ce premier segment 7a. De même, l'axe de pivotement 40 du premier levier 31 sur le cylindre 34 du vérin de déversement 26 est situé sensiblement en partie médiane de ce cylindre 34. Par ailleurs, la première bielle 30 s'étend globalement au moins sensiblement parallèlement au vérin de levage 11 entre l'axe de pivotement 12 qui la relie au châssis 3, et l'axe de pivotement 45 qui la relie au premier levier 31.The pivot axis 36 of the first lever 31 relative to the first segment 7a of the loader arm 7 is located substantially in the middle part of this first segment 7a. Similarly, the pivot axis 40 of the first lever 31 on the cylinder 34 of the discharge cylinder 26 is located substantially in the middle part of this cylinder 34. Furthermore, the first connecting rod 30 extends generally at least substantially parallel to the cylinder lifting 11 between the pivot axis 12 which connects it to the chassis 3, and the pivot axis 45 which connects it to the first lever 31.

Le vérin de levage 11 et la première bielle 30 s'étendent sous le premier segment 7a du bras chargeur 7. Le vérin de déversement 26 s'étend au-dessus de ce premier segment 7a, et le deuxième levier 32 et la deuxième bielle 33 s'étendent au-dessus de l'extrémité libre 24 du bras chargeur 7. Le premier levier 31 s'étend sensiblement transversalement au premier segment 7a pour relier la première bielle 30 au vérin de déversement 26.The lifting cylinder 11 and the first connecting rod 30 extend under the first segment 7a of the loader arm 7. The discharge cylinder 26 extends above this first segment 7a, and the second lever 32 and the second connecting rod 33 extend above the free end 24 of the loader arm 7. The first lever 31 extends substantially transversely to the first segment 7a to connect the first connecting rod 30 to the discharge cylinder 26.

Le système mécanique 30, 31, 32, 33 peut être simple, comme décrit ci-dessus, ou dédoublé, comme le bras chargeur 7. On peut ainsi prévoir deux systèmes simples de part et d'autre de chaque bras chargeur 7, et dont les éléments respectifs en correspondance sont reliés les uns aux autres transversalement. Les liaisons méca­niques à axe de pivotement mentionnées ci-dessus peuvent être réalisées par tous moyens appropriés connus : paliers, chapes, coussinets...The mechanical system 30, 31, 32, 33 can be simple, as described above, or split, like the loader arm 7. It is thus possible to provide two simple systems on either side of each loader arm 7, and of which the respective elements in correspondence are connected to each other transversely. The mechanical connections to the pivot axis mentioned above can be made by any suitable known means: bearings, yokes, bearings, etc.

Selon l'invention, chacun des vérins de déploiement 18 et de déversement 26 est un vérin à double effet commandé à partir d'une vanne 53, 54 double distributrice d'entrée/sortie reliée aux chambres d'entrée 55, 56 et de sortie 57, 58 de ce vérin 18, 26 par un circuit de commande hydraulique 59, 60. Selon l'invention, le vérin de déversement 26 est monté en série dans le circuit de commande 59 du vérin de déploiement 18, et la vanne 54 de commande du vérin de déversement 26 est reliée directement en parallèle aux chambres 56, 58 de ce vérin de déversement 26.According to the invention, each of the deployment cylinders 18 and discharge 26 is a double-acting cylinder controlled from a valve 53, 54 double inlet / outlet distributor connected to the inlet chambers 55, 56 and outlet 57, 58 of this cylinder 18, 26 by a hydraulic control circuit 59, 60. According to the invention, the discharge cylinder 26 is mounted in series in the control circuit 59 of the deployment cylinder 18, and the valve 54 of control of the discharge cylinder 26 is connected directly in parallel to the chambers 56, 58 of this discharge cylinder 26.

Le montage des circuits hydrauliques 59, 60 est illustré en figure 5. La chambre d'entrée 56 du vérin de déversement 26 est directement reliée par un conduit 61 à une première borne 62 de la vanne 54. La chambre de sortie 58 de ce même vérin de déversement 26 est directement reliée à l'autre borne 63 de la vanne 54 par un autre conduit 64. La chambre de sortie 57 du vérin de déploiement 18 est directement reliée à une première borne 65 de la vanne 53 par un conduit 66. L'autre borne 67 de cette vanne 53 est reliée par un conduit 68 au conduit 61 reliant la chambre d'entrée 56 du vérin de déversement 26 à la vanne 54. La chambre d'entrée 55 du vérin de déploiement 18 est reliée par un conduit 69 au conduit 64 reliant la chambre de sortie 58 du vérin de déversement 26 à la vanne 54.The mounting of the hydraulic circuits 59, 60 is illustrated in FIG. 5. The inlet chamber 56 of the discharge cylinder 26 is directly connected by a conduit 61 to a first terminal 62 of the valve 54. The outlet chamber 58 of this same discharge cylinder 26 is directly connected to the other terminal 63 of the valve 54 by another conduit 64. The outlet chamber 57 of the deployment cylinder 18 is directly connected to a first terminal 65 of the valve 53 by a conduit 66. The other terminal 67 of this valve 53 is connected by a conduit 68 to the conduit 61 connecting the inlet chamber 56 of the discharge cylinder 26 to the valve 54. The inlet chamber 55 of the deployment cylinder 18 is connected by a line 69 to line 64 connecting the outlet chamber 58 of the discharge cylinder 26 to the valve 54.

Les vannes 53, 54 sont conçues de telle manière que lorsque du fluide sous pression traverse l'une 65, 63 de leur borne dans un sens, le fluide traverse l'autre borne 67, 62 dans l'autre sens.The valves 53, 54 are designed such that when pressurized fluid passes through one 65, 63 of their terminal in one direction, the fluid passes through the other terminal 67, 62 in the other direction.

Avec un tel montage, on comprend que les deux vérins 26, 18 sont montés en série. Dans l'exemple représenté, la chambre de sortie 58 du vérin de déversement 26 est reliée par les conduits 64, 69 à la chambre d'entrée 55 du vérin de déploiement 18. Bien entendu, le montage inverse est possible. Selon l'invention, les deux chambres 58, 55 respectivement du vérin de déversement 26 et du vérin de déploiement 18 qui sont directement reliées l'une à l'autre, notamment par les conduits 64, 69, ont toutes deux la même section.With such an arrangement, it is understood that the two cylinders 26, 18 are mounted in series. In the example shown, the outlet chamber 58 of the discharge cylinder 26 is connected by the conduits 64, 69 to the inlet chamber 55 of the deployment cylinder 18. Of course, reverse mounting is possible. According to the invention, the two chambers 58, 55 respectively of the discharge cylinder 26 and the deployment cylinder 18 which are directly connected to one another, in particular by the conduits 64, 69, both have the same section.

Le fonctionnement de l'invention est le suivant :The operation of the invention is as follows:

Pour actionner le déploiement ou la rétraction du bras chargeur, on place la vanne 54 distributrice du vérin de déversement 26 en position neutre. Dans ce cas, les bornes 62, 63 de cette vanne sont fermées. Pour le mouvement de rétraction, le fluide hydraulique est envoyé à travers la borne 65 de la vanne 53 distributrice du vérin de déploiement 18, par le conduit 66 dans la chambre de sortie 57 de ce vérin 18. Le déplacement du piston 70 de ce vérin 18 refoule le fluide hydraulique de la chambre d'entrée 55 à travers les conduits 69, 64 la reliant à la chambre de sortie 58 du vérin de déversement 26. Le piston 71 du vérin de déversement 26 est donc également déplacé et refoule le fluide hydraulique de la chambre d'entrée 56 via les conduits 61 et 68 jusqu'à la borne 67 de la vanne 53 distributrice du vérin de déploiement 18.To activate the deployment or retraction of the loader arm, the valve 54 distributing the discharge cylinder 26 is placed in the neutral position. In this case, the terminals 62, 63 of this valve are closed. For the retraction movement, the hydraulic fluid is sent through terminal 65 of the valve 53 distributing the deployment cylinder 18, by the conduit 66 in the outlet chamber 57 of this cylinder 18. The displacement of the piston 70 of this cylinder 18 discharges the hydraulic fluid from the inlet chamber 55 through the conduits 69, 64 connecting it to the outlet chamber 58 of the discharge cylinder 26. The piston 71 of the discharge cylinder 26 is therefore also displaced and discharges the hydraulic fluid from the inlet chamber 56 via the conduits 61 and 68 to the terminal 67 of the valve 53 distributing the deployment cylinder 18.

Pour une manoeuvre de déploiement, le cheminement du fluide s'effectue en sens inverse, selon le même circuit que mentionné précédemment de la borne 67 jusqu'à la borne 65 de la vanne 53. Ainsi, on obtient une dépendance des deux vérins 18, 26 dont les tiges d'actionnement 21, 29 se déplacent au moins sensiblement de la même course, puisque les sections des chambres 55, 58 reliées sont les mêmes et que les directions des vérins sont sensiblement parallèles.For a deployment maneuver, the flow of the fluid is carried out in the opposite direction, according to the same circuit as mentioned above from terminal 67 to terminal 65 of valve 53. Thus, one obtains a dependence of the two jacks 18, 26, the actuating rods 21, 29 of which move at least substantially the same stroke, since the sections of the connected chambers 55, 58 are the same and the directions of the jacks are substantially parallel.

Pour faire pivoter l'outil 23 autour de son axe 25, la vanne 53 distributrice du vérin de déploiement 18 est placée en position neutre, ses bornes 65, 67 étant obturées. Le fluide hydraulique est envoyé par la vanne 54 distributrice dans l'une ou l'autre des chambres 56, 58 d'entrée ou de sortie de ce vérin 26 afin de l'actionner de façon classique.To rotate the tool 23 about its axis 25, the valve 53 distributing the deployment cylinder 18 is placed in the neutral position, its terminals 65, 67 being closed. The hydraulic fluid is sent by the distributor valve 54 to one or other of the inlet or outlet chambers 56, 58 of this jack 26 in order to actuate it in a conventional manner.

Selon l'invention, les vérins qui équipent la structure de levage 2, et notamment le vérin de déversement 26 et le vérin de déploiement 18 sont munis de valves régulatrices 72 de débit évitant tout décalage entre ces vérins qui pourrait se produire du fait des phénomènes de cavitation.According to the invention, the cylinders which equip the lifting structure 2, and in particular the discharge cylinder 26 and the deployment cylinder 18 are provided with flow control valves 72 avoiding any shift between these cylinders which could occur due to the phenomena cavitation.

Les vannes 53, 54 distributrices peuvent être commandées à partir de la cabine de pilotage 5 à partir de deux manettes de commande ou même d'une seule manette si ces vannes 53, 54 sont couplées. Elles sont avantageusement constituées d'électro­vannes.The valves 53, 54 distributors can be controlled from the cockpit 5 from two control levers or even a single lever if these valves 53, 54 are coupled. They advantageously consist of solenoid valves.

L'invention concerne aussi une chargeuse automotrice 1 caractérisée en ce qu'elle est équipée d'une structure de levage 2 selon l'invention. Dans le cas d'une chargeuse, chaque bras chargeur 7 est constitué uniquement de deux segments 7a, 7b téles­copiques. Un nombre plus important de segments risque de rendre la structure de levage 2 insuffisamment résistante pour les travaux importants tels que le terras­sement. Néanmoins, même avec deux segments télescopiques 7a, 7b, la structure de levage 2 selon l'invention s'est avérée être d'une résistance suffisante pour être appliquée à une chargeuse 1. L'invention peut faire l'objet d'autres applications, notamment sur d'autres types d'engins du type de travaux publics, automoteurs ou non, dès lors que les mêmes problèmes techniques s'y retrouvent.The invention also relates to a self-propelled loader 1 characterized in that it is equipped with a lifting structure 2 according to the invention. In the case of a loader, each loader arm 7 consists only of two telescopic segments 7a, 7b. A larger number of segments risks making the lifting structure 2 insufficiently resistant for important work such as earthworks. However, even with two telescopic segments 7a, 7b, the lifting structure 2 according to the invention has been found to be of sufficient strength to be applied to a loader 1. The invention can be used in other applications , in particular on other types of machinery of the public works type, self-propelled or not, when the same technical problems are encountered.

Claims (10)

1. Structure de levage pour un engin tel qu'une chargeuse comprenant au moins un bras chargeur (7) télescopique constitué d'au moins deux segments (7a, 7b) dont le premier (7a) est articulé par une (8) de ses extrémités (8, 9) au châssis (3) de l'engin (1) de façon à pouvoir pivoter au moins dans un plan vertical autour d'un axe de pivotement (10) horizontal sous l'action d'un vérin de levage (11), et dont le second (7b) coulisse selon un axe de déploiement/rétraction (17) par rapport au premier (7a) sous l'action d'un vérin de déploiement (18), la structure comprenant aussi un outil (23) associé articulé à l'extrémité libre (24) du bras chargeur (7) de façon à pouvoir pivoter au moins dans ledit plan vertical autour d'un axe de pivotement (25) horizontal sous l'action d'un vérin de déversement (26), caractérisée en ce qu'elle comporte un système mécanique (30, 31, 32, 33) de bielles et leviers articulés permettant de maintenir automatiquement constante l'assiette de l'outil (23) lors des modifications de l'inclinaison du bras chargeur (7), et en ce que les vérins de déversement (26) et de déploiement (18) sont liés hydrauliquement de façon à maintenir automatiquement constante l'assiette de l'outil (23) lors du dé­ploiement et de la rétraction du bras chargeur (7), tout en permettant, en cas de besoin, le pivotement de l'outil (23) sous l'action du vérin de déversement (26). 1. Lifting structure for a machine such as a loader comprising at least one telescopic loader arm (7) consisting of at least two segments (7a, 7b) of which the first (7a) is articulated by one (8) of its ends (8, 9) to the chassis (3) of the machine (1) so as to be able to pivot at least in a vertical plane around a horizontal pivot axis (10) under the action of a lifting cylinder (11), and the second (7b) of which slides along a deployment / retraction axis (17) relative to the first (7a) under the action of a deployment cylinder (18), the structure also comprising a tool ( 23) associated articulated at the free end (24) of the loader arm (7) so as to be able to pivot at least in said vertical plane around a horizontal pivot axis (25) under the action of a discharge cylinder (26), characterized in that it comprises a mechanical system (30, 31, 32, 33) of articulated rods and levers making it possible to automatically maintain constant the ass tool tool (23) during modifications of the inclination of the loader arm (7), and in that the discharge (26) and deployment (18) jacks are hydraulically connected so as to automatically keep the base of the tool (23) during deployment and retraction of the loader arm (7), while allowing, if necessary, the pivoting of the tool (23) under the action of the discharge cylinder (26 ). 2. Structure selon la revendication 1 caractérisée en ce que le vérin de déversement (26) est intégré au système mécanique (30, 31, 32, 33), son cylindre (34) étant articulé et prenant appui sur un premier organe (31) de ce système mécanique, sa tige d'ac­tionnement (29) étant articulée à un deuxième organe (32) du système mécanique, de sorte que ce vérin (26) constitue une bielle de longueur variable pour ce système mécanique. 2. Structure according to claim 1 characterized in that the discharge cylinder (26) is integrated into the mechanical system (30, 31, 32, 33), its cylinder (34) being articulated and bearing on a first member (31) of this mechanical system, its actuating rod (29) being articulated to a second member (32) of the mechanical system, so that this jack (26) constitutes a connecting rod of variable length for this mechanical system. 3. Structure selon la revendication 2 caractérisée en ce que le premier organe (31) est associé au premier segment (7a) du bras chargeur (7), en ce que le deuxième organe (32) est associé à la structure à proximité de l'outil (23), en ce que le vérin de déversement (26) s'étend au moins sensiblement prallèlement au vérin de déploie­ment (18), et en ce que la course de débattement du vérin de déversement (26) correspond à celle du vérin de déploiement (18) augmentée de la course nécessaire aux mouvements de pivotement de l'outil (23) dans chaque position extrême déployée et rétractée du bras chargeur (7) et du vérin de déploiement (18). 3. Structure according to claim 2 characterized in that the first member (31) is associated with the first segment (7a) of the loader arm (7), in that the second member (32) is associated with the structure near the tool (23), in that the discharge cylinder (26) extends at least substantially prallelement to the deployment cylinder (18), and in that the travel stroke of the discharge cylinder (26) corresponds to that of deployment cylinder (18) increased by the stroke necessary for the pivoting movements of the tool (23) in each extreme deployed and retracted position of the loader arm (7) and of the deployment cylinder (18). 4. Structure selon l'une quelconque des revendications 2 et 3 caractérisée en ce que le premier organe (31) est un premier levier (31) articulé au premier segment (7a) autour d'un axe de pivotement (36) horizontal, et en ce que le deuxième organe (32) est un deuxième levier (32) articulé à l'extrémité libre (24) du bras chargeur (7) autour d'un axe de pivotement (46) horizontal. 4. Structure according to any one of claims 2 and 3 characterized in that the first member (31) is a first lever (31) articulated to the first segment (7a) around a pivot axis (36) horizontal, and in that the second member (32) is a second lever (32) articulated at the free end (24) of the loader arm (7) about a horizontal pivot axis (46). 5. Structure selon la revendication 4 caractérisée en ce que le premier levier (31) est relié à l'axe de pivotement (12) reliant le vérin de levage (11) au châssis (3) de l'engin (1) par une première bielle (30) articulée à ce premier levier (31) et à cet axe (12). 5. Structure according to claim 4 characterized in that the first lever (31) is connected to the pivot axis (12) connecting the lifting cylinder (11) to the chassis (3) of the machine (1) by a first connecting rod (30) articulated to this first lever (31) and to this axis (12). 6. Structure selon l'une quelconque des revendications 4 et 5 caractérisée en ce que le deuxième levier (32) est relié à l'outil (23) grâce à une deuxième bielle (33) articulée à ce deuxième levier (32) et à cet outil (23). 6. Structure according to any one of claims 4 and 5 characterized in that the second lever (32) is connected to the tool (23) by means of a second connecting rod (33) articulated to this second lever (32) and to this tool (23). 7. Structure selon l'une quelconque des revendications 1 à 6 caractérisée en ce que chacun des vérins de déploiement (18) et de déversement (26) est un vérin à double effet commandé à partir d'une vanne (53, 54) double d'entrée/sortie reliée aux chambres d'entrée (55, 56) et de sortie (57, 58) de ce vérin (18, 26) par un circuit de commande (59, 60), en ce que le vérin de déversement (26) est monté en série dans le circuit de commande (59) du vérin de déploiement (18), et en ce que la vanne (54) de commande du vérin de déversement (26) est reliée directement en parallèle aux chambres (56, 58) de ce vérin (26). 7. Structure according to any one of claims 1 to 6 characterized in that each of the deployment cylinders (18) and discharge (26) is a double-acting cylinder controlled from a valve (53, 54) double inlet / outlet connected to the inlet (55, 56) and outlet (57, 58) chambers of this cylinder (18, 26) by a control circuit (59, 60), in that the discharge cylinder (26) is mounted in series in the control circuit (59) of the deployment cylinder (18), and in that the valve (54) for controlling the discharge cylinder (26) is connected directly in parallel to the chambers (56 , 58) of this jack (26). 8. Structure selon l'une quelconque des revendications 1 à 7 caractérisée en ce que le vérin de déversement (26) et le vérin de déploiement (18) sont munis de valves régulatrices (72) de débit évitant tout décalage entre ces vérins. 8. Structure according to any one of claims 1 to 7 characterized in that the discharge cylinder (26) and the deployment cylinder (18) are provided with regulating valves (72) flow preventing any offset between these cylinders. 9. Structure selon l'une quelconque des revendications 1 à 8 caractérisée en ce que les deux chambres (58, 55) respectivement du vérin de déversement (26) et du vérin de redéploiement (18) qui sont directement reliées l'une à l'autre, ont toutes deux la même section. 9. Structure according to any one of claims 1 to 8 characterized in that the two chambers (58, 55) respectively of the discharge cylinder (26) and the redeployment cylinder (18) which are directly connected to one other, both have the same section. 10. Chargeuse automotrice caractérisée en ce qu'elle est équipée d'une structure de levage (2) selon l'une quelconque des revendications 1 à 9. 10. Self-propelled loader characterized in that it is equipped with a lifting structure (2) according to any one of claims 1 to 9.
EP90400948A 1989-04-07 1990-04-06 Telescopic hoisting device for a vehicle, in particular for a loader Withdrawn EP0391808A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8904602A FR2645520B1 (en) 1989-04-07 1989-04-07 TELESCOPIC LIFTING STRUCTURE FOR A MACHINE SUCH AS A LOADER
FR8904602 1989-04-07

Publications (1)

Publication Number Publication Date
EP0391808A1 true EP0391808A1 (en) 1990-10-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP90400948A Withdrawn EP0391808A1 (en) 1989-04-07 1990-04-06 Telescopic hoisting device for a vehicle, in particular for a loader

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Country Link
EP (1) EP0391808A1 (en)
FR (1) FR2645520B1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2266291A (en) * 1992-04-20 1993-10-27 Caterpillar Inc Linkage for material handling device.
WO2003013999A2 (en) * 2001-08-03 2003-02-20 The Government Of The United States Of America, As Represented By The Secretary Of The Department Of Health And Human Services, Centers For Disease Control And Prevention Mobile load handling apparatus
EP2189577A1 (en) * 2008-11-20 2010-05-26 Mailleux Automatic repositioning of a worktool of a hydraulic loading implement mounted on a tractor
CN104153418A (en) * 2014-08-26 2014-11-19 广西大学 Mechanical sliding-rail type dual-driving electric excavator
US11168712B2 (en) 2019-02-22 2021-11-09 Clark Equipment Company Hydraulic leveling circuit for power machines

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2878598A (en) * 1954-06-22 1959-03-24 John S Pilch Detachable bulldozer
US3856163A (en) * 1972-07-17 1974-12-24 Case Co J I Method of using a hydraulic leveling circuit on an implement
US4344734A (en) * 1980-05-23 1982-08-17 J. I. Case Company Self-leveling bucket linkage
US4364705A (en) * 1980-07-07 1982-12-21 J. I. Case Company Loader mechanism

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2878598A (en) * 1954-06-22 1959-03-24 John S Pilch Detachable bulldozer
US3856163A (en) * 1972-07-17 1974-12-24 Case Co J I Method of using a hydraulic leveling circuit on an implement
US4344734A (en) * 1980-05-23 1982-08-17 J. I. Case Company Self-leveling bucket linkage
US4364705A (en) * 1980-07-07 1982-12-21 J. I. Case Company Loader mechanism

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2266291A (en) * 1992-04-20 1993-10-27 Caterpillar Inc Linkage for material handling device.
GB2266291B (en) * 1992-04-20 1995-09-27 Caterpillar Inc Linkage for loader bucket or other material handling device
WO2003013999A2 (en) * 2001-08-03 2003-02-20 The Government Of The United States Of America, As Represented By The Secretary Of The Department Of Health And Human Services, Centers For Disease Control And Prevention Mobile load handling apparatus
WO2003013999A3 (en) * 2001-08-03 2003-05-22 Us Gov Health & Human Serv Mobile load handling apparatus
EP2189577A1 (en) * 2008-11-20 2010-05-26 Mailleux Automatic repositioning of a worktool of a hydraulic loading implement mounted on a tractor
CN104153418A (en) * 2014-08-26 2014-11-19 广西大学 Mechanical sliding-rail type dual-driving electric excavator
US11168712B2 (en) 2019-02-22 2021-11-09 Clark Equipment Company Hydraulic leveling circuit for power machines

Also Published As

Publication number Publication date
FR2645520A1 (en) 1990-10-12
FR2645520B1 (en) 1991-08-16

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