WO2007116291A2

WO2007116291A2 - Pruning machine

Info

Publication number: WO2007116291A2
Application number: PCT/IB2007/000912
Authority: WO
Inventors: Guido Belforte; Angelo Costamagna; Giuliana Mattiazzo
Original assignee: Politechnico Di Torino
Priority date: 2006-04-07
Filing date: 2007-04-06
Publication date: 2007-10-18
Also published as: ITTO20060261A1; WO2007116291A3

Abstract

A pruning machine (1) comprises a climbing unit (2) for moving on a tree's trunk and one mobile cutting unit (4), carried by the climbing unit (2) for cutting the transverse branches of the tree. The climbing unit (2) further comprises first releasable constraining means (5), suitable for cooperating with the trunk, second releasable constraining means (6), suitable for cooperating with the trunk and linear actuating means connected between the first and second releasable constraining means (5, 6) and movable between a retracted stop position and an extended stop position, for allowing the advance of pruning machine (1) on the trunk.

Description

PRUNING MACHINE

TECHNICAL FIELD

The present invention relates to a machine for the pruning of trees having a trunk.

BACKGROUND ART

Pruning machines comprising a climbing unit for climbing the trunk and a cutting set for cutting the branches are known.

Known pruning machines comprise a wheel climbing unit that has adherence problems when the trunk bark is irregular, for example in presence of trunk's knot.

Furthermore, the wheels of the known climbing units comprise spikes to increase adherence on the trunk. During climbing, spikes damage the bark and this increases the possibility of an attack by insects.

DISCLOSURE OF INVENTION

The object of the present invention is to provide a pruning machine free from the aforesaid drawbacks.

The object of the present invention is achieved by the pruning machine according to claim

1.

BRIEF DESCRIPTION OF THE INVENTION

For a better understanding of the present invention, a preferred embodiment will now be described only by way of non-limitative example, with reference to the accompanying drawings, in which:

- figure 1 is a perspective view of a pruning machine according to thee present invention.

- figure 2 is a perspective view of a part of the pruning machine of figure 1.

- figure 3 is an enlarged perspective partial view of a part of the machine with some component hidden for a clearer comprehension. BEST MODE FOR CARRYING OUT THE INVENTION

In figure 1, numeral 1 indicates a pruning machine comprising a climbing unit 2 for moving along the trunk, a turntable 3 supported by the climbing unit 2 and a cutting unit 4 supported by the turntable 3 for cutting the branches extending from the trunk. Particularly, the climbing unit 2 comprises a first releasable constraining means 5 that supports the turntable 3, a second releasable constraining means 6 placed on the opposite side of the turntable 3 with respect to the first releasable constraining means 5 and three pneumatic cylinders 7 having a respective cylinder liner connected to the second releasable constraining means 6 and a relative rod connected to the first releasable constraining means 5 through a spherical joint.

Each releasable constraining means 5, 6 and the turntable 3 presents a substantially flattened annular shape, defining a hole 12 having an axis A in common with the other holes 12 to surround the trunk. The pneumatic cylinders 7 are parallel to axis A and angularly equispaced around the latter.

Furthermore, the turntable 3 and each releasable constraining means 5, 6 comprises a first and a second half connected with a hinge 8 at one side and with a fastener 9 in a rigid and releasable manner on the other side. Conveniently, the hinges 8 present a common axis B parallel to the axis A. When the two halves of the devices are opened, the installation of the pruning machine 1 at the base of the tree trunk is possible and when the fasteners 9 are closed, the trunk is surrounded by the turntable 3 and by the releasable constraining means 5, 6 and the pruning machine 1 is ready to work. Furthermore, in order to simplify the closing operation and to make the structure of the pruning machine 1 stiffer, the turntable 3 and each releasable constraining means 5, 6 comprise a shape coupling centering system on the respective halves defining a rigid connection when the fasteners 9 are closed.

Figure 2 shows a lower view of the first releasable constraining means 5. First releasable constraining means 5 comprises one annular housing 11 made of metal sheet, defining the hole 12 for the trunk and stiffened by radial ribs 13, comprises three linear actuators 14 fixed on the internal side of the housing 11 and converging towards axis A to define an auto-centering clamping system and also comprises three guiding devices 15 that are fixed to the internal side of the housing 11 and are suitable for defining an auto-centering clamping system.

In particular, the housing 11 comprises two head plates 16 having half-disc shape and defining the hole 12 and respective semi-cylindrical lateral walls 17 connected as previously described.

In particular the head plates 16 support the turntable 3 and the lateral walls 17 extend from the head plates 16 axially opposite to the turntable 3.

The linear actuators 14 and the guiding devices 15 are fixed to the head plates 16 around the hole 12 axially opposite to the side of the turntable 3 and are protected by the lateral walls 17.

Each actuator 14 comprises a rod 19 angularly fixed with respect to its axis and supporting a contact element 20 made of elastomeric material and defining a concave surface suitable for cooperating with the tree trunk.

Each guiding device 15 is angularly equispaced with respect to the adjacent linear actuator

14 and comprises a housing 21 fixed to the head plate 16, and a prismatic rod sliding in a guide-rail defined by housing 21. Each guiding device 15 further comprises a shoe 23 connected to a free end portion of the prismatic rod and defining a convex contact surface elongated parallel to axis A for sliding on the tree trunk.

Furthermore the prismatic rod presents a transversal pin 25 sliding in a groove 26 cut longitudinally on the housing 21.

The prismatic rod is loaded by a spring for maintaining the shoe 23 in a extracted stop position towards axis A, position defined by the groove 26 and the transversal pin 25.

At an intermediate radial distance between the lateral walls 17 and each housing 21 of the guiding device 15, the head plates 16 present a fastening portion 28 for the connection of the head of the rods of the pneumatic cylinders 7. The releasable constraining means 6 comprises a housing 29 having the same radial dimensions of the housing 11 and divided in two halves connected to each other in the same manner described above. The housing 29 is similar to the housing 11, but it is overturned and comprises a pair of lateral walls 31 extending towards the first releasable constraining means 5 from respective bottom plates 32 similar to the head plates 16. Furthemore the bottom plates 32 define three angularly equispaced holes that are the seats for respective end collars 34 of the cylinder liners of the pneumatic cylinders 7. The lateral walls 31 present a rim 31a converging towards axis A for fitting with the lateral walls 17 of the first releasable constraining means 5 as better explained afterwards. Furthemore the second releasable constraining means 6 comprises three linear actuators 35 similar to the linear actuators 14 provided with the contact elastomeric elements 20 for defining a clamping auto-centering system. The linear actuators 35 are angularly equispaced with respect to the three pneumatic cylinders 7.

At an axially opposed side of the second releasable constraining means 6 with respect to the first releasable constraining means 5, the pruning machine 1 comprises a cutting unit 4 (fig.1) fixed in a rigid manner to one of the halves of the turntable 3. The cutting unit 4 comprises a base 36 connected in a rigid way to the turntable 3, a slide

37 connected in a sliding way on the base 36 through ball bearing guideways, a chain saw

38 fastened to the slide 37 and turnable about an axis C skew and perpendicular to the axis A. The cutting unit 4 presents a pneumatic actuation system comprising a linear actuator 39 for driving the rotation of the chain saw 38 around axis C and another linear actuator (not illustrated) for driving the slide 37. Moreover, the chain saw 38 comprises a pneumatic motor 40 and a chain guide 41 having an elongated shape and presenting an end portion 41a connected to the motor 40.

In figure 3, a detailed view of turntable 3 is illustrated, in particular, the releasable constraining means 5 comprises a couple of circular rails 42a, 42b and a crown gear 43 rigidly fixed to the head plates 16 and divided in two halves as the housing 11. The circular rails 42a, 42b, and the crown gear 43 are coaxial with axis A and the crown gear 43 is interposed between the rails 42a, 42b.

The turntable 3 comprises an annular housing 44 presenting two halves divided as described above and having an internal diameter larger than the internal diameter of the housing 11. The housing 44 comprises two head plates 45 and two lateral walls 46 axially extending at an opposite side with respect the cutting unit 4 for protecting the circular rails

42a, 42b and the crown gear 43. The turntable 3 comprises a plurality of wheels 47, 48 turnable around axes parallel to the axis A and connected to the head plates 45 for cooperating respectively with the circular rails 42a and 42b and for defining a guide to the rotation of the turntable 3.

Furthermore the pruning machine 1 comprises a step-motor 49 meshing on the crown gear

43 and rigidly fixed on the head plate 45, that is not fixed to the cutting unit 4 for balancing the weight of the latter.

The pruning machine 1 is provided also with a valve block (not illustrated) controlled by a

PLC for the remote control of all the pneumatic component of the machine.

The functioning of the pruning machine 1 is as follows.

The climbing on the trunk is obtained by cyclically repeating an uphill moving sequence or a downhill moving sequence, predefined in PLC, of pneumatic cylinders 7 and linear actuators 14, 35. In particular, the pneumatic cylinders 7 are moveable between a extracted end position and a retracted end position, wherein the profile 31a of the lateral walls 31 of the second releasable constraining means 6 couples with the lateral walls 17 of the second constraining means 5. In this position, the lateral walls 17 radially constrain the first and the second constraining means 5, 6, when the linear actuators 14 are closed and the linear actuators 35 are opened. In this position the second releasable constraining means 6 is centered with respect to the first releasable constraining means 5 at each working cycle.

Furthemore, when the linear actuators 14 of the first releasable constraining means 5 are opened and the pneumatic cylinders 7 are extracting, the first releasable constraining means 5 is driven by the trunk through the guiding devices 15 that are sliding on the bark of the tree and that can adapt to the different diameters and irregularities of the tree trunk such as knots because the shoes 23 are slidable along a radial direction.

It is possible to provide a quick advancing function and a slow advancing function, both controlled by the PLC and chosen by the operator using a remote control.

When the machine is near a branch, all the linear actuators 14 and 35 are closed against the trunk. The pneumatic cylinders 7 are pressurized for recovering the axial clearance and to block the machine 1 to the trunk. In this way, the connection of the pruning machine on the trunk is stiffened and allows to support the characteristic loads of the cutting operations without collapses.

Furthermore the slide 37 is extracted and touches the trunk using a portion 37a through which a pressure against the bark is generated and the position of the machine is made additionally more rigid. In this condition, the linear actuator 39 is actuated for making the chain saw 38 rotating on a plane perpendicular to the axis C and for making the saw cutting the branch.

The cutting speed normally reachable using the chain saw are high enough for avoiding the clamping of the branch for a correct cutting operation.

With the pruning machine 1 above described it is possible to obtain the following advantages.

The use of the climbing unit 2 comprising the pneumatic cylinders 7, allows the machine to easily climb also an irregular trunk.

The housings 11 and 29, defining annular closed structures, and the use of shape coupling closed by fasteners 9 allows to obtain a very rigid machine more capable to withstand to the different loads arising during the clearance recovery operations and cutting operations.

The guiding devices 15 avoid that the first releasable constraining means 5 loads the trunk due to gravity and gets stuck into the bark, when the linear actuators 24, 35 are retracted. The slide 37 and the possibility of rotation around the axis C make the cutting operations more versatile, also because the slide 37 is in contact with the trunk during the cutting for making the cutting position more stable and favouring the cutting.

The use of a chain saw 38 having an elongated guide 41 allows the machine to be more compact axially than a machine with a circular saw considering the maximal branch diameter that can be cut.

Furthermore, the cutters of the chain are laterally disposed to allow cutting also in cases of small settlements of the linear actuators 14, 35 and to avoid jamming of the chain in the wood.

Clearly, changes may be made to pruning machine 1 as described and illustrated herein without, however, departing from the scope of the present invention as defined in the accompanying Claims.

For example, the valves' block can be used, if needed, as additional balancing weight to be added to the machine besides the step-motor 49.

It is also possible to provide for the presence of a contact sensor for stopping the climbing of the pruning machine in case the machine goes in contact with a branch.

Claims

1. Pruning machine (1) comprising a climbing unit (2) to climb a trunk of a tree and a mobile cutting unit (4) carried by said climbing unit (2) to cut the transversal branches of a tree, characterized in that said climbing unit (2) comprises first releasable constraining means (5) suitable for cooperating with said trunk, second releasable constraining means (6) suitable for cooperating with said trunk and linear actuating means (7) connected to said first and second releasable constraining means (5, 6) and movable from an extracted stop position and a retracted stop position to allow the machine to move on said trunk.

2. Pruning machine according to claim 1 , characterized in that one of said first and second releasable constraining means (5, 6) defines a first rigid structure (11; 29) closed in use to define a hole (12) having an axis (A) suitable to surround said trunk.

3. Pruning machine according to claim 2, characterized in that another of said first and second releasable constraining means (5, 6) defines a second rigid structure (29, 11) closed in use to define a hole (12) having an axis (A) suitable to surround said trunk.

4. Pruning machine according to claim 3, characterized in that said first and second rigid structure (11 , 29) comprise respective halves presenting shape coupling means.

5. Pruning machine according to claim 3 or 4, characterized in that said first and second releasable constraining means (5, 6) comprises respective first and second clamping auto-centring units (14, 35).

6. Pruning machine according to claim 5, characterized in that at least one of said first and second clamping auto-centring units (14, 35) comprises a respective pneumatic cylinder carried by the relative rigid structure (11, 29) around the relative hole (12).

7. Pruning machine according to claim 6, characterized in that it comprises a plurality of concave contact elements (20) carried by the ends of the rods of said pneumatic cylinders (14, 35) to cooperate with said trunk.

8. Pruning machine according to any of the preceding claims, characterized in that it comprises clearance recovering means (7) connected to said first and second releasable constraining means (5, 6) for producing a force that tends to modify the distance between said first and second releasable constraining means (5, 6) when said first and second releasable constraining means (5, 6) are closed on the trunk.

9. Pruning machine according to any of the preceding claims, characterized in that said first and second releasable constraining means (5, 6) comprises respective first and second radial centering element (17, 31a) coupled when said linear actuating means (7) are in said retracted stop position.

10. Pruning machine according to claim 9, characterized in that said linear actuating means (7) comprises at least one pneumatic cylinder presenting a rod connected to said first releasable constraining means (5) and a cylinder liner presenting an end collar (34) connected to said second releasable constraining means (6).

11. Pruning machine according to any of the preceding claims, characterized in that said cutting unit (4) is movable along a straight line with respect to said first and second releasable constraining means (5, 6) from an extracted stop position and a retracted stop position.

12. Pruning machine according to claim 11 , characterized in that said cutting unit (4) comprises a second contact element (37a) suitable for cooperating with the trunk when said cutting unit (4) is in said extracted stop position.

13. Pruning machine according to any of the preceding claims, characterized in that said cutting unit (4) is rotatable about a second axis (C) transversal with respect to said linear actuating means (7).

14. Pruning machine according to claim 13, characterized in that said cutting unit (4) is a chain saw unit and comprises a motor (40) and an elongated chain guide (41) having an end portion (41a) connected to said motor (40).

15. Pruning machine according to any of the preceding claims, characterized in that said first releasable constraining means (5) comprises a plurality of shoes (15) suitable for cooperating with said trunk.

16. Pruning machine according to claim 15, characterized in that said shoes (15) comprise respective sliding elements (22) loaded by a spring in an extracted stop position. ,

17. Pruning machine according to any of the preceding claims, characterized in that said cutting unit (4) is connected to a support unit (3) rotatable about an axis (A) parallel to said linear actuating means (7), and characterized in that it comprises a counterweight (49) placed on said support unit (3) for balancing said cutting unit (4), and comprises a motor for controlling the rotation of said support unit (3).

18. Actuating method for a pruning machine (1) comprising a cutting unit (4) for cutting the transversal branches of a tree, first releasable constraining means (5) supporting said cutting unit (4) and suitable for cooperating with said trunk, second releasable constraining means suitable for cooperating with said trunk and linear actuating means (7) connected between said first and second releasable constraining means (5, 6), said actuating method comprising the phases of: o closing said first and second releasable constraining means (5, 6) on the trunk, o actuating said linear actuating means (7) for exerting a force the tend to change the distance between said first and second releasable constraining means (5, 6). o actuating said the cutting unit (4)/