FR3009549A1 - ARTICULATED SUPPORT FOR A HANDLING APPARATUS SUCH AS A CRANE, AND FORESTRY TRACTOR COMPRISING A CRANE ROTATING ON SUCH AN ARTICULATED SUPPORT FIXED ON A TRACTOR CHASSIS - Google Patents

Abstract

The invention relates to a support (10) for a handling device such as a crane (3), articulated support intended to be fixed on a mobile frame (1) such as a forest tractor chassis, support comprising: • a platform (20) defining a main plane, • a plate (30) intended to support the handling device, the plate being secured to the platform by means of a first ball joint (40) comprising a ball (41) secured to the platform and cooperating with a ring (46) fixed under the plate so that a center of the ball forms a center of rotation of the ring on the ball, and • anti-rotation means to prevent rotation of the ball. ring on the roture along an axis perpendicular to the plate. The support according to the invention is characterized in that the anti-rotation means comprise a flange (50) of which: • a first end (51) is secured to the ring (46) of the first ball joint connection, • a second end ( 52) is secured to the platform (30) via a second ball joint (60). The invention also relates to a tractor comprising an articulated support as described below.

Description

Articulated support for a handling device such as a crane, and forest tractor comprising a crane rotatably mounted on such an articulated support fixed on a tractor chassis Technical field and state of the art The invention relates to an articulated support for a device handling equipment such as a crane. Such a support is particularly intended to be fixed on a forest tractor chassis. In order to exploit the forest resources, forest tractors conventionally comprising a chassis, chassis drive means such as a plurality of wheel pairs or a track system coupled to a drive motor, and a crane attached to a tractor are used. the frame, generally rotatably mounted relative to an axis perpendicular to the frame. The free end of the crane can be equipped with a trunk gripper, a cutting tool, etc., depending on the work to be done on the trees. For most forest tractors equipped with conventional cranes and used today, the manufacturers themselves do not recommend their use in rough terrain with a slope greater than 8 to 100 inclination In fact, for inclines of slope greater than 8 at 10 °, when the crane is unfolded, the center of gravity of the crane moves and comes to the vertical of the tractor seat. If the center of gravity of the crane exceeds the tractor seat, the tractor is unbalanced and tilts. However, forest resources in Europe are 60% in the mountains or more generally in areas with rugged terrain, with slopes that can be well above 10 °. It is known from Dl = US6105699 a forestry tractor comprising an articulated crane foot, allowing an upgrade of the platform supporting the crane so that the platform supporting the crane is kept horizontal, and the upstream arm of the crane is maintained in a vertical plane, regardless of the slope of the terrain. Specifically in Dl, the crane is fixed on an articulated support as defined in the preamble of the claim, that is to say comprising: a platform defining a main plane, the platform being fixed on the chassis of the tractor, a platform for supporting the crane, the plate being secured to the platform by means of a first ball joint comprising a first ball integral with the platform and cooperating with a first ring fixed under the plate so that a center of the first ball forms a center of rotation of the first ring on the first ball, - tilting means, more precisely four cylinders, for tilting the plate by a predefined angle relative to an axis perpendicular to the main plane of the platform and anti-rotation means for preventing a rotation of the ring on the ball along an axis perpendicular to the plate. The crane is mounted on a pivoting foot with respect to u plate, along an axis perpendicular to the plate, and means are provided to control the rotational movement of the foot of the crane relative to the plate. The tilting means make it possible to level the platform supporting the crane, compensating for an inclination of the platform and the chassis linked to the slope of the ground.

The anti-rotation means are necessary to prevent any undesired and undesired rotation of the plate relative to the platform, along an axis perpendicular to the plate. In D1, the anti-rotation means consist of a bar passing through the ball in a through recess provided for this purpose; said bar is secured to the plate by means of a pivot connection where all the forces related to the load of the crane are carried over two bearings positioned at the ends of the bar and which work in friction, especially during a rotation of the plate along an axis substantially parallel to the main axis of the bar. These efforts, particularly important during the handling of trunks, result in a rapid wear of the bearings, with a risk of rupture likely to result in a fall of the crane. DESCRIPTION OF THE INVENTION The invention proposes a new articulated support, allowing a leveling of the crane continuously, but whose robustness is improved. More specifically, the invention provides a support for a handling device such as a crane, support comprising a platform hinged on a platform. The invention also proposes a forestry tractor comprising: - a chassis, - means for driving the chassis in motion, - a support according to the invention, support whose platform is secured to the chassis, - tilting means for tilting the chassis, plateau of a predefined angle with respect to an axis perpendicular to the main plane of the platform, and - a crane mounted on the support.

The support according to the invention comprises: - a platform (20) defining a main plane, - a plate (30) intended to support the handling device, the plate being secured to the platform via a first link ball (40) comprising a ball (41) integral with the platform and cooperating with a ring (46) secured to the plate so that a center of the ball forms a center of rotation of the ring on the ball, and - means anti-rotation to prevent a rotation of the ring on the roture along an axis perpendicular to the plate, The support according to the invention is characterized in that the anti-rotation means comprise a flange of which: - a first end (51) is secured to the ring (46) of the first ball joint, - a second end (55) is secured to the platform (30) via a second ball joint (60).

In known manner, the means for tilting the plate relative to the axis perpendicular to the main plane of the platform comprise for example a jack whose one end is secured to the plate and a second end is secured to the platform. Several jacks can also be envisaged, preferably distributed around the periphery of the plate, as described in document Dl.

It will be noted that, since the support according to the invention does not comprise any elements hindering the inclination of the plate with respect to the platform (no bar crossing the first ball joint connection, for example), the support plate according to the invention can be tilted in all directions, that is 360 degrees. In addition, in all directions, the angle of inclination is limited only by the dimensions of the first ball and the foot of the ball. Thus, with for example a plateau of approximately 0.75 m and a ball diameter greater than 0.3 m, it is possible to easily reach angles of inclination varying between 0 and 25 °. The ring is for example welded or bolted under the plate, and it preferably has a spherical internal surface, of adjusted dimensions outer diameter of the ball to ensure a connection without play between the ball and the ring; also the spherical internal shape of the ring provides a large contact area between the ring and the ball, for a better distribution of the forces related to the load of the ring plate to the ball.

The flange, rigid and integral with the platform and the ring, prevents any rotation of the ring on the ball of the first ball joint connection along the axis perpendicular to the platform. But as the flange is secured to the platform by a ball joint, the flange authorizes and follows the movements of the plate on the first ball joint. Thus the flange does not interfere with the leveling of the platform compensating the inclination of the platform. The flange providing the anti-rotation function is positioned outside the elements (ball and ring) forming the first ball joint. During the work of the crane, the loads related to the load are reported only on the first ball joint and are distributed over the entire contact surface of the ring on the ball. The flange providing the anti-rotation function, external to the ball joint, receives no or very little effort related to the load of the crane and therefore does not wear prematurely. The support according to the invention is thus much more robust than the support of Dl.

Preferably, the first end of the flange is secured to the first ring by a pivot connection along a pivot axis which passes through the center of rotation of the first ball joint and which is parallel to the plate. Thus, the relative movements of the first ring relative to the flange are facilitated. According to one embodiment, the second ball joint can comprise a second ball (61) integral with the platform (20) and cooperating with a recess (56) pierced at the second end (55) of the flange, a center of the second ball forming the center of rotation of the flange on the second ball (61). According to a variant, the recess (56) has a spherical internal surface of dimensions adjusted to the dimensions of the second ball (61) to ensure a play-free connection between the recess and the second ball. According to another variant, the recess has a cylindrical internal surface, and the second ball joint is completed by means for limiting any translational movement of the recess along an axis perpendicular to the platform. Since load-related efforts are not reported on the second pivot link, the latter does not need to be sized as robust as the first one.

According to another embodiment, the second ball joint connection may comprise a ball integral with the second end (55) of the flange and housed inside a spherical or cylindrical recess pierced in a mechanical part secured to the platform; the mechanical part is for example a ring having a cylindrical recess.

The flange is for example made from a metal bar or portions of bars secured (for example welded) to one another, of circular section (round iron) and / or rectangular section (flat iron). According to a variant, the flange is a single flange, extending in a single direction, the second end of which is intended to be secured to the platform, and whose first end is intended to be secured to the first ring. According to another variant, the flange is a double flange, V-shaped, a tip of the V forming the second end of the flange to be secured to the platform, and the free ends of the branches of the V-flange forming first ends of the flange to be secured to the first ring, preferably on either side of the center of rotation of the first ring. This V shape allows a distribution of the ring forces on the branches of the flange.

On the ring of the first ball joint, the realization of the pivot connection connecting the flange and the ring depends on the embodiment of the flange. Thus, according to a variant adapted to a single flange, the ring may comprise a substantially cylindrical pin extending along the axis of pivoting, pin adjusted to rotate without play along the axis of pivoting within a recess of corresponding cylindrical shape positioned at the second end of the flange. The pin and the first end of the flange thus form a pivot connection, allowing a rotation of the first ring relative to the flange along the axis of rotation. According to another variant adapted to a double flange, the first ring may comprise two substantially cylindrical pins extending along the axis of pivoting on either side of the first ring, the two pins being adjusted to rotate without play according to FIG. pivot axis inside two associated recesses positioned at the free ends of the legs of the V-flange. The pivot connection between the flange and the first ring facilitates the inclination movements of the plate relative to the platform, while prohibiting the rotation of the plate along any axis perpendicular to the plate. In practice, the first pivot connection must be able to withstand all the efforts related to the load of the handling tool (the crane, for example) intended to be supported by the plate. The first pivot connection must therefore be dimensioned accordingly. The second pivot connection, however, supports little effort. Thus, the diameter of the first ball is preferably selected from the order of 0.2 to 0.6 m, 2 to 5 times larger than the diameter of the ball of the second pivot connection. The flange is also chosen of the order of 0.05 to 0.2 m: the lever arm between the two pivot connections is thus quite short so that the efforts of the first pivot connection on the second pivot connection are limited. According to another variant, for a better distribution of the forces, the anti-rotation means comprise two flanges; each flange comprises: - a first end of each flange is secured to the ring of the first ball joint by a pivot connection, the same pivot connection for the two flanges, - a second end of each flange is secured to the platform by the intermediate a second, respectively a third ball joint, and the two flanges are positioned on either side of the ring of the first ball joint, symmetrically with respect to a plane passing through the axis of inclination of the plateau and the axis of the pivot connection solidarisant the flanges to the ring. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other characteristics and advantages of the invention will emerge in the light of the following description of an example of implementation of a forest tractor according to the invention, comprising: a crane rotatably mounted on the support according to the invention. This example is given as a non-limiting example. The description is to be read in conjunction with the accompanying drawings in which - Figure 1 is a partial perspective view of a forest tractor according to the invention - Figure 2 is a partial perspective view of an embodiment of the invention. a support according to the invention, - Figure 3 is a view of a ball of the first ball joint of a support according to the invention - Figure 4 is a perspective view of an embodiment of a flange. of a support according to the invention - Figure 5 is a front view of another embodiment of a support according to the invention, and - Figure 6 is a view of a detail of Figure 5.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION The appended figures show a forest tractor essentially comprising: - a chassis 1, - means 2 for driving the chassis in motion, - the essential element of the invention, namely a articulated support 10, tilting means for inclining the plate by a predefined angle with respect to an axis Z perpendicular to the main plane of the platform, and a crane 3 mounted on the support. The chassis 1 and the means 2 for driving the chassis in motion are made according to widely known techniques, in the example two axles (only one shown) each driving two wheels. The support 10 according to the invention essentially comprises a plate 30 articulated on a platform 20 integral with the frame 1. For this, the plate is secured to the platform via a first ball joint 40 comprising a female ball joint cooperating with a male ball joint, so that a center of the female socket forms a center of rotation of the male ball joint on the female ball.

In the examples shown, the female ball is a ball 41 of which one foot 42 is integral with the platform 20; the male ball is a ring 46 fixed (for example welded) under the plate, which ring has a spherical inner surface of dimensions adjusted to the outer diameter of the ball. The outer surface of the ring is for example spherical (Figures 1, 2) or cylindrical (Figure 5, 6).

The tilting means of the plate are for example (FIGS. 1, 5) constituted by four jacks 25, a first end of which is connected to the platform 20 and a second end of which is connected to the plate 30, associated with a control means (no shown) which simultaneously controls the length of the four jacks. The use of appropriate jacks makes it possible to obtain inclinations of up to 25 ° with respect to the Z axis. The foot 42 of the ball 41 serves as a stop for the ring 46 (FIG. 6) to limit the inclinations of the pole. .

The crane 3 comprises a crane leg 4, an upstream arm 5, a downstream arm 6 and a tool. The crane foot 4 is rotatably mounted on the plate 20 relative to an axis perpendicular to the plate; for this, in the example shown: - a ring gear is fixed on the plate 20, - the crane foot 4 is fixed on a toothed disc mounted fitted inside the ring gear so that an axis of symmetry the toothed disk is coincident with an axis of symmetry of the ring gear, axis of symmetry perpendicular to the plate, and so that the teeth of the disk meshing with the teeth of the ring, - means are provided for driving in rotation the toothed disk relative to the ring gear, along the axis of symmetry of the ring gear, with a torque and / or a controlled rotational speed. One end of the upstream arm 5 is connected to the crane foot 4 by a pivot connection along an axis parallel to the plate so that the upstream arm is rotatable relative to the plate along an axis R1 parallel to the plate. The two arms 5, 6 of the crane are articulated by a pivot connection along an axis R2 parallel to the axis Ri. Thus the two arms of the crane can be deployed, unfolded, in a plane perpendicular to R1, R2. At the free end of the downstream arm 6 is fixed a tool, such as a gripper 7 (grapple) or a cutting tool (not shown).

The support according to the invention is characterized by anti-rotation means comprising a flange 50 of which: - a first end 51 is secured to the ring 46 of the first ball joint - a second end 55 is secured to the platform via The shape of the ends 51, 55 of the flange depends on how the flange is secured to the first ball joint and how the second ball joint is made. In the examples shown, the flange is a V-shaped double flange, a tip of the V forming the second end 55 of the flange, and the free ends of the branches of the V-flange forming the first ends 51 of the flange. The first end of the flange is secured to the ring 46 by a pivot connection along a pivot axis Y which passes through the center of rotation of the first ball joint, which is parallel to the plate 30; in the examples shown, the pivot axis is also orthogonal to an axis X defined by the center of rotation of the first ball joint 40 and the center of rotation of the second ball joint 60, for a symmetrical distribution of the ring forces on the flange; also, the pivot axis and the X axis are in the same plane substantially parallel to the platform, to limit the shear forces on the flange. In the example of Figures 1, 2, 4, the ring of the first ball joint comprises two pins 47 extending along the pivot axis Y on either side of the ring 46; the two pins 47 are adjusted to pivot without play along the pivot axis Y inside two associated recesses 52 positioned at the free ends of the branches of the V-shaped flange. In the example of FIGS. 5, 6, from and other of the ring 46, two portions of axis Y1, Y2 are secured to the plate 20 by means of fixing lugs and are adjusted to rotate without play inside respectively the two recesses 52 of the flange 50 It is recalled that the ring 46 is integral with the plate 30.

The second end 55 of the flange is secured to the platform via the second ball joint 60 which comprises a female part and a male part. The second ball joint is preferably made so that the X axis passing through the center of rotation of the first ball joint and the center of rotation of the second ball joint is substantially parallel to the platform. This is not necessary, however. In the example of FIGS. 1, 2, 4, the female part consists of a ball 61 secured to the platform 20 by an axis 62 held orthogonal to the platform 20 inside a fastening lug 63 ; the male part is constituted by a cylindrical recess 56 pierced at the second end 55 of the flange; the axis of the recess 56 is substantially parallel to the axis 62 when the plate 30 is parallel to the platform 20. In the example of FIGS. 5, 6, the female part consists of a ball welded to the second end 55 of the flange, and the male part is constituted by a hollow cylinder secured to the platform by fixing lugs, so that an axis of the cylinder is substantially parallel to the platform. As an indication, a prototype was made , in which: - the tray is tilted with respect to the Z axis, in a controlled manner, up to 25 °, and in all directions, - the ball diameter of the first ball joint connection is 0.30 m, the diameter of the ball of the second ball joint is 0.1 m, and the V branches of the flange measure about 1 m As previously mentioned, a forest tractor according to the invention essentially comprises: - a chassis 1 - means 2 for driving the chassis in motion the essential element of the invention, namely an articulated support, tilting means for inclining the plate by a predefined angle with respect to the Z axis perpendicular to the main plane of the platform, and a crane 3 mounted on the support. The tilting means allow, continuously, during the movements of the tractor in rough terrain, to maintain the horizontal plateau, regardless of the inclination of the ground. The support, with its horizontal plate, thus allows to have a crane always positioned in a vertical plane, which works with limited shear forces at the level of the crane foot. For this, the platform inclination means comprise in particular: an inclinometer, positioned on the platform, for determining an angle and a direction of inclination of the platform, and therefore of the chassis, with respect to a fixed terrestrial reference system; means for continuously adjusting the height of the cylinders to tilt the plate relative to the platform, to permanently bring the plateau in a horizontal plane relative to the terrestrial reference.

The adjustment means is in practice a computer and electronic means: - able to produce for each cylinder a control signal of a desired height, - from signals provided by the inclinometer, representative of the angle of inclination and the tilt direction of the platform. The adjustment means is preferably part of a larger computer and electronic means providing complete control of the tractor, including the handling device. Nomenclature 1 chassis 2 means for driving the chassis 10 articulated support platform jacks plate 20 40 first connection ball 41 ball 42 foot of the ball 46 ring 47 two pins 25 50 flange 51 first end of the flange, secured to the first link ball 40 52 recesses 55 second end of the flange, secured to the second ball joint 60 60 second ball joint

Claims (10)

REVENDICATIONS1. Support (10) for a handling device such as a crane (3), articulated support for attachment to a frame (1) movable such as a forest tractor chassis, support comprising: - a platform (20) defining a main plane, - a plate (30) for supporting the handling device, the plate being secured to the platform via a first ball joint (40) comprising a ball (41) integral with the platform and cooperating with a ring (46) integral with the plate so that a center of the ball forms a center of rotation of the ring on the ball, and - anti-rotation means to prevent rotation of the ring on the roture according to a perpendicular to the plate, the support being characterized in that the anti-rotation means comprise a flange (50) of which: a first end (51) is secured to the ring (46) of the first ball joint, a second end; (55) is secured to the laterforme (30) via a second ball joint (60). 2. Support according to claim 1, wherein the first end (51) of the flange (50) is secured to the ring (46) by a pivot connection along a pivot axis (Y) which passes through the center of rotation of the first ball joint (40) and which is parallel to the plate (30). 3. Support according to one of claims 1 to 2 wherein the second ball joint (60) comprises: - a second ball (61) integral with the platform (20) and cooperating with a recess (56) pierced at the second end (55) of the flange, a center of the second ball forming the center of rotation of the flange on the second ball (61), or - a ball integral with the second end (55) of the flange and housed inside a spherical or cylindrical recess pierced in a mechanical part secured to the platform (20). 4. Support according to one of claims 2 to 3 wherein the ring (46) comprises a substantially cylindrical pin (47) extending along the pivot axis (Y), pin adjusted to rotate without play along the axis pivoting within a recess (52) of corresponding cylindrical shape positioned at the first end of the flange. 5. Support according to one of the preceding claims wherein the anti-rotation means comprise a V-shaped double flange, a tip of the V forming the second end (55) of the flange secured to the platform, and the free ends of the branches of the V flange forming the first ends (51) of the flange secured to the ring (56), on either side of the center of rotation of the first ring (56). 6. Support according to the preceding claim wherein the ring (46) comprises two pins (47) substantially cylindrical extending along the pivot axis (Y) on either side of the ring, the two pins being adjusted to pivot without play along the axis of pivoting within two recesses (52) associated positioned at the free ends of the legs of the flange V. 7. Support according to one of claims 2 to 5, wherein a diameter of the ball (41) of the first knuckle connection is 2 to 5 times larger than a diameter of the ball of the second ball joint. 8. Support according to one of the preceding claims wherein in the first ball joint, the ring (46) preferably has a spherical inner surface, of dimensions fitted to the outer diameter of the ball (41). 9. Support according to one of the preceding claims wherein the handling device is rotatably mounted on the plate, along an axis perpendicular to the plate. 10. A tractor comprising: - a frame, - means for driving the frame in motion, - a support according to one of the preceding claims, support whose platform is secured to the frame, - tilting means for tilting the plate. a predefined angle relative to an axis perpendicular to the main plane of the platform, and - a crane mounted on the support.