ROBOT HEDGE TRIMMER

Abstract

The invention relates to a hedge-trimming robot that automatically works on the outer edge of a hedge. The outer edge is defined by a support cable stretched between two guide structures installed opposite each other, i.e., fixed at each end of the hedge. Equipped with electric motors, the device comprises two carriages that move along these guide structures. Between these carriages, a taut support cable moves a cutting tool that trims the outer edge of the hedge via a shearing motion created by a variation in the tension of the support cable. The invention is electronically controlled to ensure the automation of the work. The device allows the same robot to be disassembled and reassembled on several hedges, provided that each hedge is equipped with its own facing guide structure. The invention is powered by mains electricity or a battery and / or solar panel.

Description

Title of the invention: ROBOT HEDGE TRIMMER

[0001] The invention relates to the field of recreational or professional gardening and has as its object the automatic trimming of hedges or any volume with organic growth which may be the subject of regular maintenance work. It is a hedge trimmer robot working automatically on an envelope defined by a carrier cable stretched between two guide structures installed opposite one another, that is to say fixed at each end of the hedge. The robot is equipped with electric motors. State of the prior art

[0002] Hedge trimming is tiring and dangerous, especially when cutting at height. The use of stepladders, ladders and other garden scaffolding makes this job even more dangerous.

[0003] For hedges at the edge of fields or roads, there are hydraulically articulated hedge trimmers mounted on agricultural tractors. However, these methods are not suitable for garden hedges, which are smaller, less accessible to large vehicles and require precise trimming.

[0004] The state of the art in hedge trimming therefore consists largely of manual trimming using portable electric or thermal tools.

[0005] The aesthetic quality of the plant surface is proportional to the frequency of pruning, that is to say to the regularity of the cutting of the shoots. The manual nature implies a limitation of the frequency of intervention.

[0006] The manual nature of the size also implies a lack of precision.

[0007] The spacing of the pruning generates more voluminous plant waste during the intervention. Given the volume, it is not possible to leave this waste on site, and in turn it generates evacuation work.

[0008] Although no pruning automation device is available on the market, there are several patented hedge trimming robot inventions. The state of the art of automatic hedge trimming systems consists of movable elements moving parallel to the hedge on a guide rail or gantry. The movement carried out in a repetitive and automatic manner prevents the hedge from growing beyond the volume defined by the trajectory of the movable element. a. A rail at the top of the hedge or on the ground guides a mobile gantry which follows the profile of the hedge and whose edges are sharp or equipped with an abrasive element and whose simple mechanical contact prevents plant growth, without cutting the shoots exceeding the limits of said volume (document WO02096186 - 05 / 12 / 2002 - SOLAR & ROBOTICS SA -BE) b. A rail is laid on the ground on foundations along the hedge and allows manual effort to be reduced and precision to be improved; however, manual intervention is still necessary to push the hedge trimmer onto its rail (document FR2680444 - 26 / 02 / 1993 MADEC GUY - FR) c. A rail guides one or two or three shearing arms which can partially or completely surround the hedge; each of the arms can move linearly and thus adapt to different hedge dimensions; this system resembles three hedge trimmers assembled on a gantry (document DE3024806 Al - 1982-01-28 MAYER KARL DE) d. A rail or roadway along the hedge allows a carriage to be moved by hand or by motor over all surfaces to be cut using adjustment devices; the hedge trimmer being fixed to an adjustable mast mounted on the carriage (document DE2848372 Al - 1980-05-22 MANGOLD JUERGEN)

[0009] However, these machines are all guided by rails or roadways, which has the disadvantage of costly installation, particularly on uneven ground.

[0010] These inventions have not reached the commercialization stage due to their complexity of installation or production. Summary of the invention

[0011] The present invention relates to an automatic assembly consisting of: a. two guide structures (1) installed opposite each other, i.e. fixed at each end of the hedge; b. two carriages (2 and 3) themselves circulating from one end to the other of these two guide structures; c. a carrying cable (7) stretched between the two trolleys (2 and 3) (movement “x” along the hedge); d. a mobile working element called a shear block (4) moving along the carrier cable (7).

[0012] The movement of the shear block moved by the carrier cable on the hedge envelope can be broken down into two directions: a. a movement along an “x” axis along the hedge: “x” movement along the carrier cable (7); b. a movement along a “y” axis, which axis is folded back on itself as much as necessary to match the profile of the hedge: “y” movement along the guide structures (1).

[0013] The two guide structures (1) must be installed opposite each other at each end of the hedge. These opposite structures follow the profile of the hedge. The hedges commonly having a rectangular profile, said structures are hereinafter referred to as "arch" (1). The two arches (1) must be installed on the same principles and in the same way as an end post must be installed at the beginning or end of the fence. In particular, the arch (1) must: a. Have a “T” profile providing a continuous rolling guide or rail (1.2) from one end to the other, to allow the smooth movement of the “y” wheels (2.2 and 3.2) of the trolleys (2 and 3). These “y” wheels (2.2 and 3.2) are grooved wheels, guided by the rail (1.2) and driven by an electric “y” motor (2.1 or 3.1). The transitions between two straight sections of the arch (1) exclude sharp angles in favor of transitions by curved sections (1.1). These curved sections (1.1) may have a radius of curvature as small as the movement of the “y” wheels (2.2 and 3.2) allows; b. Be strong enough to withstand the tension force of the cable (7), by being founded in the ground either using cement or directly in the earth. Struts (6) usefully complement the capacity to withstand tension. The sizing of the foundations and the struts (6) are a function of both the height of the hoops (1) and the tension of the cable (7), as a result of the force generated by a lever arm. These general principles of post installation are known and applied, for example, by companies installing garden fences.

[0014] In order to adapt to different heights and widths of hedges, the facing guide structures (1) can be made up of: a. standard straight T-shaped posts, usually intended for the installation of garden fencing; for example the T30 post (30mm x 30mm), widely distributed in DIY and gardening stores; b. modular kit comprising curved sections (1.1) of varying length and curvature, allowing connection to said rectilinear posts; this kit makes it possible to form the curved parts of the hoops (1). The connection to the rectilinear posts is ensured by bolts fixing a female part (1.3) to a male part at the base of the T, it being understood that the two wings of the T must remain free and continuous to allow the free passage of the carriages (2 and 3) on the rail (1.2).

[0015] Thus the facing guide structures (1) can adapt not only to rectangular hedges of different heights and widths, but also to a quasi-infinite number of hedge profiles provided that they are reproducible by said modular kit.

[0016] Each hoop (1) is provided with a motorized carriage (2 or 3) driven by a single “y” wheel (2.2 or 3.2). Each carriage (2 or 3) also includes a pair of grooved side wheels (2.4 or 3.4). This constitutes a set of 4 side wheels (2.4 or 3.4) which allows a carrier cable (7) closed on itself to be tensioned to form a single loop.

[0017] This tensioned carrying cable (7) applies a traction force that the two carriages (2 and 3) each transmit to their “x” wheel (2.4 or 3.4), which wheels thus ensure the adhesion of their carriage (2 and 3) to the arch (1). The two carriages (2 and 3) thus move from one end of their respective arch (1) to the other (movement “y”) using their “y” wheel (2.2 or 3.2) rotated by their motor (2.1 or 3.1). The carriages (2 or 3) are asymmetrical with a master carriage (2) on the one hand and a slave carriage (3) on the other hand.

[0018] The master carriage (2) is equipped with a motor (2.1) for moving in "y" on the arch (1) as well as a second "x" motor (2.3) for actuating the shear block (4). It is also equipped with end-of-travel sensors (reversal of the "y" movement). When these sensors come into contact with one of the two end-of-travel indicators positioned at the appropriate location on the arch (1) of the master carriage (2), the master carriage (2) changes direction "y", that is to say it goes back towards the other end of the arch (1).

[0019] The slave carriage (3) is, on the other hand, equipped with a single “y” motor (3.1), which “y” motor (3.1) is controlled by the master carriage (2) in that it changes direction of travel - “y” movement along the arch (1) - at the same time as the “y” motor (2.1) of the master carriage (2). The slave carriage (3) has neither limit switches nor “x” motor for actuating the shear block (4).

[0020] The synchronous movement of the two carriages (2 and 3) opposite each other being essential for the proper functioning of the system, the control of the slave carriage (3) to the master carriage (2) makes it an isostatic and synchronous system. The carrier cable (7) thus always remains horizontal, provided that the two carriages (2 and 3) have been installed at the same horizontal level relative to each other.

[0021] The master carriage (2) is equipped with a second “x” motor (2.3) ensuring both the movement of the shear block (4) along the hedge (movement “x”) and the oscillating movement of said shear (4). This double movement is obtained by the two plates of the double eccentric wheel (2.8).

[0022] The upper plate of the double eccentric wheel (2.8) subjects the oscillating frame (2.5) to an oscillation along the “x” axis (back and forth movement). This upper plate is eccentric and is in contact with an ovoid shape inside the oscillating frame (2.5). The curvature of this ovoid shape makes it possible to distribute the traction force exerted by the “x” motor (2.3), while the diameter and the degree of eccentricity of the double eccentric wheel (2.8) make it possible to adjust the amplitude of the oscillation. The oscillating frame (2.5) is on the one hand constrained in a sliding movement (“x” movement) - for example via sliders (2.6) applied for example along the “x” motor body (2.3) - and on the other hand tensioned by the carrying cable (7), the rotation of the upper plate of the double eccentric wheel (2.8) produces an oscillation along the “x” axis. The two “x” side wheels (2.4) for tensioning the carrying cable (7) being fixed on this oscillating frame (2.5), its oscillation causes the same movement of the “x” side wheels (2.4) which thus vary the tension of the carrying cable (7) between a minimum tension (Tmin in kg or N) and a maximum tension (Tmax in kg or N).

[0023] The lower plate of the double eccentric wheel (2.8) consists of a grooved wheel and can for its part come into contact - therefore engage - with the carrier cable (7) to make it run in two distinct modes, allowing two distinct modes of movement of the shear block (4).

[0024] Installation option 1: contact via counter wheels. When the master carriage (2) reaches the end of travel “y”, the lower plate of the double eccentric wheel (2.8) comes into contact with a pair of counter wheels “x” (5) fixed to the stake, which forces the carrying cable (7) to come into contact with the lower plate of the double eccentric wheel (2.8). In which case the movement “x” of the shear block (4) is triggered only punctually at the end of travel “y”. The length of this movement “x” is adjustable by adjusting the rotation time of the motor “x” (2.3) after the motor “y” (2.1) has stopped at the end of travel “y”.

[0025] Installation option 2: direct contact at each rotation. When the oscillating frame (2.5) is in the low or relaxed position (Tmin), the lower plate of the double eccentric wheel (2.8) has been positioned in such a way that it comes into contact with the carrying cable (7) during each rotation; in which case the “x” movement is triggered alternately with the shearing movement, i.e. an x ​​movement concomitant with the “y” movement. The length of this “x” movement is adjustable by adjusting the length of the groove of the double eccentric wheel (2.8) brought into contact with the carrying cable (7).

[0026] The carrier cable (7) being installed in a closed loop, its punctual drive by the lower plate of the double eccentric wheel (2.8) has the effect of making it run on the four lateral wheels (2.4) and of making the shear block (4) advance on the “x” axis.

[0027] Ensuring a simple role of returning the carrying cable (7) - movement "x" - the controlled carriage (3) is only equipped with two lateral wheels (3.4) fixed on a fixed non-oscillating carrying frame (3.5).

[0028] The shear block (4) consists of two standard hedge trimmer blades, a blade (4.1) and a counter-blade (4.2), each of which is fixed to one of the ends of the loop of the carrier cable (7): a. The blade (4.1) is fixed on one side to the first end of the carrying cable (7), and on the other side to a spring (4.3) of constant R. This double fixing ensures alignment and stability of the shear block (4); b. The counter-blade (4.2) is carried by the blade (4.1) and is secured to a rigid return rod (4.4) which transmits to it the movement of the other end of the carrying cable (7); c. When the tension of the carrying cable (7) changes and due to the tension of the spring (4.3), the two ends of the carrying cable (7) move relative to each other by Delta (mm) = R (N / mm) * (Tmax -Tmin) (N). This length Delta corresponds exactly to the elongation of the spring (4.3) between Tmin and Tmax. The shears are thus subjected to a relative movement of the blade (4.1) and the counter-blade (4.2) relative to each other, in other words a shearing movement. d. Two alignment rods (4.5) complete the shear block (4) to ensure its alignment in the plane drawn by the loop of the carrier cable (7). The opposite side of the carrier cable (7) passes through the ends of these two rods (4.5). The carrier cable (7) slides freely without hindering the movement of the shear block (4), which thus follows the same orientation in space as that of the loop of the carrier cable (7). This control ensures that the shear (4) is always parallel to the surface of the hedge.

[0029] The spring (4.3) can be either a tension or compression spring. The compression spring or dynamometric spring is equipped with draw-bars and is better protected against excessively high tension. Its use is therefore recommended with regard to the robustness of the device.

[0030] The whole is controlled by an electronic card with the following functions: a. Automatic start and stop at a fixed day and time; b. Reversal of the direction of rotation of the motors according to the instructions received via the limit switches. c. Stopping the assembly at a “y” point or basic position using the basic switch; this means that the assembly does not have to be immobilized with the carrier cable (7) at man height when a passage is made in the hedge; d. Return to base position when a humidity sensor detects humidity preventing the shears from operating correctly on plants; e. Emergency stop button f. The adjustment of this electronic function as well as the possible addition of additional sensors allows to program a “random” cutting mode or an “intelligent” cutting mode. In random mode, the shearing unit (4) works randomly over the entire surface, and statistical distribution over a determined working time ensures uniform work. In intelligent mode, the assembly controls the shearing unit (4) to work uniformly

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] each part of the hedge envelope, depending on the area to be covered. The power supply for the whole unit can be provided: a. By a 220 V mains source supplying a low voltage transformer; b. By a battery to be recharged periodically on the 220 V mains; c. By a battery continuously recharged by a power solar panel adapted to the battery's needs and the sunshine in the region; The risk of electrocution from the unit is zero, as it operates at very low voltage. The risk of cutting by the shear block (4) is mitigated by: a. the tension Tmin of the carrier cable (7) must be sufficient to keep the shear block (4) well aligned between the two carriages (2 and 3) even in windy weather; however, the shear force does not need to be high, because the shear, due to its continuous nature, is exerted on young leaves and other new plant growth. The shear force is a function of the tension difference Tmax - Tmin. This tension difference can be adjusted by adapting the torque of the oscillation amplitude "x" of the oscillating frame (2.5) and the spring constant (4.3). This constant must be high enough to tension the carrier cable (7), but it can decrease beyond Tmin. In the case of a spring (4.3) in compression, this reduction beyond a threshold tension can be achieved by pre-compressing a spring (4.3) of low constant, which spring only begins to be compressed by a second stiffer spring when the latter has reached its maximum compression just when it has been subjected to Tmin. b. It is advisable to prevent any contact with the shear block (4) by using a safety shell protecting the outer side of the shear block (4). The whole thing is waterproof so you can stay in place in all weather, including rain. The assembly and disassembly of the unit is facilitated by: a. A clamp for holding the carriages (2 and 3) on the hoop (1), which holds the carriages (2 and 3) in position during the assembly and disassembly phases, i.e. when the tension of the carrying cable (7) is not able to hold the carriages (2 and 3) in position on the hoop (1); b. A tensioner / detentor for the carrier cable: equipped with a ratchet, this tensioner allows the tension of the carrier cable (7) to be easily adjusted to reach the nominal working tension. Easy assembly and disassembly allow the trolleys (2 and 3) and the shear block (4) to be reused on several hedges previously fitted with fixed hoops (1). Simply to dismantle them from a first hedge sufficiently trimmed to mount them on a second hedge requiring trimming work. An alternative reuse option consists of dismantling only the trolleys (2 and 3), excluding the carrier cable (7) and its shear block (4). This makes it possible to dedicate a carrier cable (7) specifically sized for a given hedge, which is intended to remain in position throughout the growing season. The choice between these two options can be arbitrated by favoring either ease of reuse or economic optimization (minimum purchase of parts).

[0037] The invention thus provides professionals (maintenance companies, technical services of local authorities, etc.) or individuals with a tool suitable for maintaining plant areas that need to be trimmed regularly, particularly hedges.

[0038] The scope of the present invention is not limited to the embodiment described above and considered as an example, but on the contrary extends to modifications within the reach of those skilled in the art. List of figures

[0039] [Fig-1] Perspective view of the assembly, master carriage side (2)

[0040] [Fig.2] Perspective view of the assembly, servo-driven carriage side (3)

[0041] [Fig.3] Front view of the master carriage (2) and the shear block (4)

[0042] [Fig.4] Perspective view of the master carriage (2) and the shear block (4)

[0043] [Fig.5] Overall plan

[0044] [Fig.6] Plan of the master carriage (2)

[0045] [Fig.7] Master carriage plan (2) - Exploded view

[0046] [Fig.8] Plan of the servo-driven trolley (3)

[0047] [Fig.9] Plan of the shear block (4)

[0048] [Fig. 10] Counter Wheel “x” (5)

[0049] [Fig 11] Guide structure (1) - Curved connection

Claims

Claims

1. Device for maintaining a hedge or any volume with organic growth, characterized in that it comprises two guide structures (1) facing each other reproducing the profile of the hedge and fixed to each of its ends, as well as a carrying cable (7) stretched between two carriages (2 and 3) set in motion on said guide structures (1) using motors, which carrying cable (7) allows the movement of a working tool (4) on the surface of the volume.

2. Device according to claim 1, characterized in that the movement of the working tool (4) is generated by a variation in tension of the carrying cable (4).

3. Device according to claims 1 or 2, characterized in that the working tool (4) is a shear whose blade (4.1) and counter-blade (4.2) are set in motion by tension or compression of a spring (4.3) deforming under the effect of the variation in tension of the carrying cable (7).

4. Device according to one of claims 1 to 3, characterized in that one or more carriages (2 or 3) generate a tension variation effect and a displacement effect of the working tool (4), by means of a double eccentric wheel (2.8) or any other means.

5. Device according to one of claims 1 to 4, characterized in that the facing guide structures (1) placed at the ends of the hedge are modular to adapt to all types of profile to be maintained; among others arch profiles (1) or any profile formed by a series of rectilinear sections and curved sections (1.1).

6. Device according to one of claims 1 to 5, characterized in that the assembly and disassembly of the carriages (2 and 3) is facilitated by a holding clamp and a tensioner of the carrying cable (7) so that said carriages (2 and 3) can be moved on different guide structures (1) opposite each other and thus be usable for the maintenance of several hedges in parallel.

7. Device according to one of claims 1 to 6, characterized in that it can be automated by means of an electronic circuit, to ensure regular work.

8. Device according to one of claims 1 to 7, characterized in that its electrical power supply is provided either by the 220 V mains, or by rechargeable battery, or by battery plus solar panel.

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