FR2458987A1 - Machine for cutting grass - has upper and lower contra rotating belts driven by pulleys and fitted with flexible wires to provide continuous cutting action - Google Patents

Abstract

The machine comprises a chassis (2) equipped with a handle, rear wheels and a single central front wheel (13). The power unit (6) has two output shafts (17,18) one each end in the horizontal plane. Gears (19-22) drive upper and lower pulleys (31-34) on vertical shafts (23,24) and belts (7,8) run over these pulleys and centrally positioned tensioning pulleys (37,38). One shaft drives the upper pulley, the lower pulley being free. The other shaft operates in the opposite mode. The belts run in contra-rotating directions and are equipped with teeth or flexible wires, which provide a continuous scissors-type cutting action.

Description

 The present invention essentially relates to a machine for cutting grass.

 Many types of machines for cutting or mowing grass have been known in the art.

 All known machines have drawbacks and most of them are dangerous machines.

 According to a first type, the machine usually called a mower essentially comprises a heavy blade rotating at high speed in a substantially horizontal plane, at the desired cutting height and under a protective casing. The blade which rotates around its center of inertia comprises two sharp in the direction of attack. Experience shows that many distracted users intervene on the machine before the blades come to a complete stop, for example to remove an object that has wound up on the blade, having its fingers sliced off. In addition, if the blade rotating at high speed encounters a pebble or a piece of metal, it is thrown away constituting a dangerous projectile, not to mention the damage that may result for the blade. as much more dangerous as to be effective, the blade must rotate at high speed and have a high inertia.

 According to another known type of machine, a cylinder is used comprising at its periphery helical blades which rotate around the axis of the cylinder and which pass when they rotate at a short distance from a fixed horizontal blade forming a counter knife. These machines, once pushed by hand, give a nice cut. They can however only be used on very well-kept lawns with well-groomed soil and if the grass is not too high. They also remain relatively dangerous because of the knives they comprise, especially if they are equipped with a drive motor.

 According to another type of known machine, operating on the principle of the hedge trimmer, a motor operates in reciprocating movement back and forth two blades in the shape of a comb whose teeth, when they cross in the movement of back and forth come to cut the herbs that are committed to each other. The advantage of these machines is that they can be passed through grasses as tall as they are. Among the drawbacks, it can be noted that they do not allow the collection of cut grass and that they are very dangerous because it is practically not possible to provide for the use of a protective casing at the level of the blades. .

 According to another type of machine, usually called "mower-shredder", the machine comprises, driven in rapid rotation about a substantially horizontal axis, a whole series of knives articulated at a certain distance from said axis around axes also horizontal parallel to the axis of rotation of the machine. Under the effect of centrifugal force, the knives orient themselves substantially radially with respect to the axis of rotation. As a result, the grass is cut and also crushed by a multitude of small articulated knives which strike it at high speed. Knives being articulated, the meeting with a hard or bulky body is done without too much trouble, because the relatively weak knife of inertia can be erased. Such a machine cuts and reduces in small fragments as well grass as brambles or even copses according to the power of the machine and the size of the knives. Pushed on a wheel or self-supporting, it can be used for mowing lawns as well as for cleaning roadsides or very dirty ground. Among the disadvantages, it should be noted that it is a very dangerous machine which must be handled with all the required caution. On the other hand, the cut is not very straightforward and the device is not suitable for the maintenance of beautiful lawns, the grass marking a certain yellowing after the cut, which disappears from the rest a few days later.

 Machines have also been proposed comprising a sort of circular saw mounted at the end of a handle and making it possible to cut everything that the disc encounters. Such a device is obviously very dangerous, while its handling is not convenient, except for proceeding in certain inaccessible places such as recesses, feet of wall, etc. More recently, a rotary disc has been proposed comprising, as a sawtooth, wires, usually of a nylon-like plastic material. Such a machine called "grass cutting wire" is interesting because the low inertia of the nylon thread makes it practically harmless, however making it possible to cut grass in inaccessible corners such as the feet of shrubs, corners of wall, etc. Unfortunately, such a machine, taking into account the principle implemented, can only have a very low yield and can only be used in practice to "tweak" the main cut made by a conventional machine. On the other hand, the cut is not straightforward, the grass being as much torn off and crushed as cut.

 The object of the present invention is to provide a machine for cutting the grass which overcomes the difficulties mentioned by being both perfectly efficient in terms of yield, perfectly efficient in terms of cutting ensuring a clean and clean cut whatever the height of the grass to be cut and which, moreover, is practically harmless, being unable for example to cut a finger even if it comes into contact with the cutting members. In addition, the machine object of the invention must allow reach all places, even inaccessible places such as nooks, feet of trees and shrubs, etc. In addition, we will provide at will the possibility, either of an automatic collection of the cut grass, or of leaving grass on the spot, for example if we want to let it dry in hay or if the we want to compost it on the spot.

 The grass cutting machine according to the invention for achieving these objects is of a type using flexible or articulated cutting members capable of being erased by bending or hinging when they meet a more as hard or as important as that for which they are intended for cutting, this machine being characterized in that it comprises two distinct families of said cutting members which are driven in parallel and opposite directions adjacent to the cutting plane. Ohw understands that in this way, when the machine progresses by encountering grass to be cut in front of it, each blade of grass is mowed by being caught between two adjacent cutting members driven in opposite directions, the way it would be cut by the two branches of a pair of scissors. Consequently, each cutting member working while being assisted in a counter-cutting movement by an adjacent member moving in the opposite direction, the cut obtained is much more effective for a much less effort to be provided. However, unlike a shearing movement in which it is necessary to open the branches of the shears after each action, a continuous cutting movement is obtained according to the invention without dead time.

 On the other hand, each branch of the shears formed by each pair of cutting members crossing by moving in the opposite direction, being flexible or articulated, there is no blockage or deterioration of the machine if it comes to meet a body that is too hard or too large, such as a pebble, a tree base, etc. This makes it possible to use the machine even in inaccessible recesses and to clear perfectly and properly shrubs planted on a pleasure lawn or to weed plantations such as for example vine plants or fruit trees.

 On the other hand, the principle of "shearing" cutting being very effective, the cutting members can be very light and of low inertia, for example constituted by flexible wires or fins, made of suitable plastic or other material which will prevent any serious injury, for example in the event of inadvertent contact of the cutting elements with the fingers.

 According to an advantageous characteristic of the invention, the cutting members are mounted in the vicinity of each other and of the cutting plane on two belts or bands which drive them and which are themselves driven in parallel rectilinear movements and in direction opposite, at least over part of their length forming the cutting edge of the machine. For example, each of the belts could be driven in a determined direction on at least two pulleys between which it is tensioned, one of the two pulleys at least being driving.

The invention, its implementation and various characteristics which result therefrom will become more clearly apparent with the aid of the description which follows, given with reference to the appended drawings in which
FIG. 1 shows in profile and schematically a machine designed according to the invention,
FIG. 2 is a diagrammatic view over the machine illustrated in FIG. 1,
- Figure 3 schematically shows a section taken substantially in the planes III of Figure 2 of the means for driving the cutting members according to the principle of the invention.

 FIG. 4 shows in exploded view in perspective how the various elements illustrated in FIG. 3 can be mounted on a plate forming the chassis of the machine.

 - Figures 5 and 6 show on a larger scale two belts provided with cutting members which can be used according to the invention.

 FIGS. 7 and 8 show the same belts seen from the side according to the respective arrows VII and VIII of FIGS. 5 and 6.

 - Figure 9 shows in perspective another belt quite similar to that illustrated in Figure 5.

 - Figure 10 shows in perspective another belt provided with cutting members that can be used according to the invention.

 - Figures 11 and 12 show in perspective view two belts provided with cooperating cutting members that can be used.

 FIG. 13 shows another mounting of a belt of use substantially equivalent to the belts illustrated in FIGS. 11 and 12.

 We will first refer to Figures 1 to 4 of the drawings.

 A machine 1 essentially comprises a support frame 2 supported and rolling on wheels 3 which can be pushed by arms 4 with two branches 4a, 4b joined by a support bar 5. On the frame 2 is mounted a motor 6 which serves to the drive in the opposite direction of two belts 7, 8 which themselves carry the cutting members as will be described later.

 In the example illustrated, the motor 6 being mounted at the front of the machine and cantilevered with respect to the wheels 3, an additional caster 10 is advantageously provided in front of the wheels 3.

 The caster 10 is pivotally mounted about an axis 11 whose position can be adjusted in height by means of a key 12 which can be engaged in different holes formed in the axis 11 and in a tube 13 fixed on the support frame 2 .

 In the description, it is assumed that the machine will normally be pushed forward in the direction of arrow 9 (Figure 1).

 Advantageously, and as it appears more clearly in FIG. 4, the support frame 2 is formed by a simple sheet metal suitably stamped.

 This plate makes it possible to provide simply a certain number of lugs as visible at 14, 15, 16 for the respective fixing of the axes of the wheels and of the ends of the arms 4a, 4b of the arms 4.

 In the front part, the plate receives the engine block 6.

This has been shown diagrammatically by a cylinder, which may correspond to reality if the machine is driven electrically. Obviously, however, any other type of engine can be used, and in particular a gasoline engine.

 The motor 6 drives a horizontal axis whose ends come out and appear at 17, 18 (Figures 3 and 4). On these ends are mounted conical pinions or toothed rings 19, 20 which directly drive two other conical pinions 21, 22 mounted at the upper end of two vertical axes 23, 24.

 It immediately appears that when the axis 17, 18 of the motor turns in one direction, the two vertical axes 23, 24 are driven in opposite directions, as shown by the arrows.

 The mounting of the axes 23, 24 can be done for example by means of bearings 25, 26 mounted in the plate 2 and 27, 28 mounted in lugs 29, 30 which can be added welded to the plate 2 further conformed directly in this plate.

 On the axis 23, is mounted wedged on this axis an upper pulley 31, and crazy on this same axis a lower pulley 32 at a short distance from the pulley 31.

 In the same way, an upper pulley 33 is mounted on the loose axis 24 and wedged on this axis an adjacent lower pulley * 34.

 On the upper pulleys 31, 33, a belt or band 7 is stretched, and in the same way on the lower pulleys 32, 34 is mounted a belt or band 8 between which the cutting plane 70 is formed.

 The tensioning of the belts is advantageously obtained by using two additional rollers or pulleys 37, 38 which press said belts outwards and forwards giving the belt seen from above (FIG. 2) a V shape with a point. forwardly Keeping the rollers 37, 38 at an appropriate height is obtained by mounting these rollers turning idly around an axis 39 inside a stirrup 40 mounted articulated around a pivot 41 and urged by a spring 42 (Figure 3). The pivot 41 pivots in an orifice 43 provided for this purpose in the plate 2.

 In FIG. 4, we also see the height adjustment roller 10 with its pivot 11 which can be engaged in the sleeve 13 welded to the plate 2 The roller 10 must be able to rotate not only around its rolling axis 44 but also around the axis of its pivot read, and so as not to interfere with the handling of the machine.

 Returning to FIGS. 1 and 2, we also see a double removable and optional cowling comprising at the front a chute 45 and behind a cowling 46 covering a part 47 formed partly by the plate 2 and partly by a protective plate 48 can constitute a reservoir to receive the cut grass as it will appear later. Of course, in this case, side walls and a rear wall 49 limit the volume of the tank.

 Reference will now be made to FIGS. 5 to 8 which illustrate a first embodiment of the actual cutting members entered in the opposite direction by leseou = wies 32.36 identified 7, previous auxfiires.

 In the example illustrated, the belts are flat belts which can be made of any suitable flexible material based on rubber, a suitable plastic material and / or mineral or synthetic fibers.

 The upper belt 35 carries fine fins 50 having a relatively tapered leading edge 51. They are inclined at an angle apart from the drive direction 52 of the belt, this angle possibly forming, for example, between 30 and 600.

 A short distance from the fins 50, are carried on the adjacent lower belt 36 cooperating fins 53 which form with the direction of movement 54 (in the opposite direction of 52) of the belt 36 an angle ss. This angle P will advantageously be smaller than the angle, and for example between 10 and 20.

 As can be clearly seen in FIGS. 7 and 8, the shape of the fins is such that they project beyond the outside face of the belts 35, 36 with their leading edges 51, 54 coming substantially in tangency, so that when the fins 50 cross the fins 53, their cutting edge 51 comes to cut against the rim 54 of feedback of the fins 53 any blade of grass being nearby.

 Since the belts can rotate at high speed, hundreds of basic scissor cuts per second are easily obtained on the advancement front of the machine formed in V in front of the pulleys 33, 37, 31 (FIG. 2).

 However, each fin 50,53 which can be very flexible can be produced so that it cannot seriously injure, for example, fingers inadvertently coming into contact with it.

 It will also be noted in FIG. 5 that the rapid rotational movement of the belt creates, taking into account the inclination of the fins 50, and in the manner of the fins of a turbine an air intake towards the high in the direction of arrow 55, while the fins 53, slightly inclined, practically do not disturb this aspiration.

 As a result, the grass cut by the fins 50 is both projected by the inclination of these fins and sucked upward by the upward air stream 55, this movement being able to be used to entrain the grass. cut in the chute 45 and from there into the tank 47 as illustrated in FIGS. 1 and 2.

 However, if for some reason one does not wish to collect the cut grass, it can be thrown aside by a simple modification of the outlet of the chute 45.

 According to the variant embodiment of the belt illustrated in FIG. 9, it can be seen that this time it is a toothed belt 56 comprising fins 57. For the rest, these belts can be of identical or similar conformation to those illustrated in Figures 5 to 8.

 According to the embodiment of the belt illustrated in FIG. 10, there is a toothed belt 58 which comprises, as cutting member, simple sections of wire 59, for example made of nylon. Advantageously, such belts will be used in conjugation, taking care that the wires 59 of the two adjacent lower and upper belts move in planes slightly spaced from each other so as to ensure the desired shear cutting movement.

 According to the embodiment illustrated in FIGS. 11 and 12, two conjugated belts 60, 61 have loops 63, 64 for example made of nylon, for cutting.

 According to the embodiment illustrated in FIG. 13, the belt 65 comprises as cutting member loops 66 which are formed by a thread for example of interchangeable nylon 67 which can be passed on either side into grooves 68 formed on a side of the belt.

 In the illustrated embodiment which has been described, it will be noted that the carrying wheels 3 of the machine pass inside the track 69 (FIG. 2) which has been cut by the cutting members mounted on the belts 7, 8 , 35, 36, .etc. This is advantageous because it avoids crushing the grass under the carrying wheels 3 of the machine before cutting it and the rolling force is simultaneously reduced. This also has the advantage of allowing good recess even of inaccessible corners, further facilitated by the V shape that the cutting front draws.

 However, such an assembly is not compulsory and provision can be made for substantially mounting the engine assembly and the belts between the carrying wheels. In such a solution, the caster 10 becomes superfluous and it suffices to provide any means known per se enabling the height of the suspension of the whole machine to be modified relative to the axis of the wheels. The advantage of such a solution is that it makes it possible to better protect the cutting members between the wheels, the disadvantage being that the machine can less easily access in nooks or near the feet of the tree if the space is not wide enough to leave the passage of the wheels.

 Many variants can be made to the embodiment illustrated and described. In particular, the tensioning of the belts can be carried out by rollers directly pushed against the internal face of the belts. The place of thrust where a rounded V-shaped point will form can be offset with respect to the axis 70'cl ' advancement of the machine, for example to the left or to the right, or even be provided towards the rear so that the cutting front of the machine would be straight, the belts being stretched forward on the pulleys 31, 33, 32 , 34.

 Although the machine has been described as being pushed on two carrying wheels, the machine can be self-propelled, or even self-propelled by a tractor.

 Also, it is possible to multiply the number of pairs of belts working in the fauehage, by. example if you want to cut the grass more finely.

 Various exemplary embodiments of belts have been shown, but many others can be used. Thus, the belt can be reduced to a simple stretched wire to which the cutting members will be hung, such as, for example, the sections of wire 59 of the belt illustrated in FIG. 10.

 Conversely, if it is desired to carry out major brushcutting work, the cutting members may be constituted by steel blades or teeth, such as chain saw teeth. iwans such an assembly, the machine must obviously be handled with all the usual precautions, with however the advantage on known machines that one hardly risks any jet of projectiles and no offset of the machine because of the movements in opposite direction of Combined cutting members cooperating in mowing. It will be noted that the same machine can be used with different cutting members depending on the work it has to do, the adaptation resulting from a simple exchange of the belts on the pulleys, exchange which can be done very quickly and does not require no tools.

  Also, although the machine has been described in a preferred embodiment where the belts are continuously driven in the same direction, one can optionally provide a drive in reciprocating motion or vibrations back and forth of the belts, provided care is taken that the two cooperating belts vibrate or move alternately at each moment in opposite directions.

In such an arrangement, the motor mechanism must obviously be adapted accordingly.

 The invention is therefore in no way limited to the illustrated and described embodiments which have been given only by way of example, comprising all the technical equivalents of the means described as well as their combinations if these are carried out according to its spirit and implemented in the context of the following claims.

Claims (10)

 1. A machine for cutting grass of a type using flexible or articulated cutting members capable of being erased by bending or hinging when they meet a body which is harder or more important than that for which they are being cut. provided, said machine being characterized in that it comprises two distinct families of said cutting members which are driven in parallel and opposite directions adjacent to the cutting plane.  2. Machine according to claim 1, characterized in that said cutting members are mounted in the vicinity of each other and of the cutting plane on two belts or bands which drive them and which are themselves driven by parallel rectilinear movements and opposite direction, at least over part of their length forming the cutting edge of the machine.  3. Machine according to claim 2, characterized in that each of the belts is driven in a determined direction on at least two pulleys between which it is tensioned, one of the two pulleys at least being powered.  4. Machine according to claim 3, characterized in that at least one additional pulley or a roller ensures the tensioning of the belt.  5. Machine according to one of claims 2 to 4, characterized in that for the drive in opposite directions of the two belts, the machine comprises a motor driving along a horizontal axis two toothed rings or bevel gears which each drive in opposite directions a vertical axis, each vertical axis carrying two pulleys for driving said two belts, one of the pulleys forming the driving pulley being wedged on the axis, the other forming a crazy rotating gear.  6. Machine according to one of the preceding claims, characterized in that it comprises means for adjusting the height relative to the ground of said cutting members.  7. Machine according to one of the preceding claims, characterized in that said cutting members are formed by loops or strands of wire projecting beyond the outer face of said belts.  8. Machine according to claim 7, characterized in that said loops are formed by passing a wire through slots provided on a side face of the belt.  9. Machine according to one of claims 1 to 7, characterized in that said cutting members are formed by fins integral with the outer face of said belts and advantageously coming from material with them.  10. Machine according to claim 9, characterized in that said fins form an ascending air stream helping the ejection of the cut grass and its path through a conduit suitably shaped towards a discharge tank carried on the machine.