GB2149635A

GB2149635A - A machine, such as a hedge cutter, for performing operations on vegetation

Info

Publication number: GB2149635A
Application number: GB8428549A
Authority: GB
Inventors: Der Lely Cornelis Van
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1983-11-17
Filing date: 1984-11-12
Publication date: 1985-06-19
Also published as: GB8428549D0; GB2149635B; NL8303941A

Abstract

A hedge cutter comprises a two pivotally interconnected arms (17, 20). One arm (20) carries two working members (2, 3) which are pivotable on the arm (20) independently of each other. As a result, the working members can be positioned, for example, to work the top and one side of a hedge (78) in a single pass. Other configurations can be adopted for other purposes. For example, working member (2) leads the other (3) by a distance which exceeds the width (62) of the member (2) in the travel direction (Figure 7). <IMAGE>

Description

SPECIFICATION A machine, such as a hedge cutter, for performing operations on vegetation This invention relates to a machine, such as a hedge cutter, for performing operations on vegetation, for exampleshrubsand other plants.

Such machines are used, forexample, for cutting hedges and for mowing road verges and the banks of watercou rses.

According to one aspect ofthe present invention there is provided a machine for performing operations on vegetation, comprising at least two drivable working members which are mounted on a carrierfor movement between at least two positions at different vertical levels, the inclination oftheworking members with respect to each other being adjustable.

With a machine constructed in accordance with the present invention, operation in two planes atan angle to one another can be achieved in a single pass. For example, the working members can be relatively set so that the top and the standing side of a hedge can be worked in one pass. Moreover, other surfaces which are at an angle to one another can beworked,for example along roads and watercourses. With a machine in accordance with the present invention, a job can be more readily carried out, which appreciably increases the productivity ofthe machine.

An advantageous embodiment in accordance with the present invention is obtained when the working members are relatively independently adjustable with respectto the carrier and are optionally fixable in one of at least two positions relative to the carrier.

According to a second aspect ofthe present invention there is provided a machine for performing operations on vegetation, comprising at least two drivableworking members disposed one ahead of the other, with respect to the normal direction of operative travel ofthe machine, the working members being mounted on a carrier for movement between at least two positions at different vertical levels. The working members can thus be readily set in the desired relative positions without hindering each other. The construc tion of, in particular, the connection ofthe working members with the carrier can then be simple. The working members can be set in an advantageous relative position forworking adjoining surfaces by arrangingtwoworking membersonacarriersoasto be movable about a common pivotal axis.

The machine may comprise at least two working members coupled with a frame, which is pivotally connected with the carrier. The frame can be moved into a desired position relative to the carrier, and the working members are adjustable with respecttothe frame for obtaining theirdesired relative positions.

The machine may be provided with more than two working members so that each ofthe working members is adjustable with respect to the other working members.

The working members may be mounted on the carrierfor adjustment about a pivotal axis extending transversely ofthe normal direction of operative travel. In this way the number of potential positions of the working members can be readily increased. The utility ofthe machine is improved in a simple manner if it is provided with coupling means for attaching itto the lifting device of a tractor or a similar vehicle.

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure lisa rearview of a tractor provided with a hedge cutter; Figure 2 is an enlarged view on the line ll-ll in Figure 1; Figure 3 is a sectional viewtaken on the line Ill-Ill in Figure 2; Figures 4 and 5 correspond to Figure 1, but show the hedge cutter in different configurations.

Figure 6 corresponds to Figure 1 but shows another embodimentofa hedge cutter; Figure 7 is a view in the direction ofthe arrow VII in Figure 6; Figures 8 to 10 show different configurations for the hedge cutter of Figure 6.

The hedge cutter shown in Figures 1 to comprises a carrier 1, on which working members 2 and 3 are mounted so as to be adjustable with respect to the carrier 1 about a pivotal axis 4. The carrier 1 comprises coupling means 5 by which the hedge cutter can be hitchedtothethree-point lifting device of a tractor 6 as shown in Figure 1. The coupling means 5 comprises a horizontal beam 10providedwith lugs 11 forattaching the coupling means to lifting arms 12 of the three- point lifting device of the tractor. A bracket 13 is fastened to the beam 10, and the top ofthe bracket can be coupled by a top rod 14with upperfastening lugs 15 ofthe three-point lifting device ofthe tractor.

The carrier 1 comprises a main arm 17, which is pivotally connected to the beam 10 by a pivotal shaft 18. The end ofthe main arm 17 away from the pivotal shaft 18 is pivotally connected to a side arm 20 by a pivotal shaft 19. The pivotal shafts 18 and 19 are parallel to the axis 4 and to a vertical plane extending in the normal operative direction oftravel, indicated by an arrow V in Figure 2. The main arm 17 is adjustable by means of a hydraulic adjusting member 21 and can be fixed atwill in any one of a plurality of positionsabouttheaxisofthe pivotal shaft 18. The hydraulic adjusting member 21 is fastened to a lug 22 secured to one end of the beam 10 and a lug 23 secured to the main arm 17. The adjusting member 21 comprises a hydraulic cylinder from which a piston rod extends.Another hydraulic adjusting member 24 comprising a cylinder and a piston rod acts between the main arm 17 and the side arm 20. The adjusting member 24 is connected to a lug 25 on the main arm 17 and to an adjusting arm 26, which is rigidly secured to the side arm 20. The adjusting arm 26 extends on the side ofthe pivotal shaft 19 opposite the side arm 20, as will be apparentfrom Figure 1.

Atthe end away from the pivotal shaft 19, the side arm 20 is provided with lugs 30 and 31 which are spaced apart and situated near opposite sides of the arm.The lugs 30 and 31 hold a pivot pin 32,the centre line of which constitutes the pivotal axis 4. The pivot pin 32 projects at both ends from the side arm 20. At the front end, with respectto the direction V, it is fastened to a beam 33 of a frame (not otherwise shown) oftheworking member2. The working member2 is situated ahead ofthearm 20 and comprises a shaft 34 which is provided in this embodimentwith clapper-shaped mowing members orflails.The ends ofthe clappers move around a cylindrical surface 35 which is coaxial with the shaft 34, part ofthis plane 35 being surrounded by a hood 36 mounted on the beam 33.

The centreline 27 ofthe shaft 34 crosses the pivotal axis 4. The working member2 is rigidly secured to the pivot pin 32 and, thus, is rigidly secured to an adjusting sleeve 37 which is rigidly secured to the pivot pin between the tongues 30 and 31 by a pin 38.

The adjusting sleeve 37 has two spaced adjusting arms 39 (Figure 3), which are pivotally connected by pivot pins 40to intermediate arms 41. The ends ofthe intermediate arms 41 away from the pivot pins 40 are coupled by a pivotal shaft 42 with a bearing 43 provided atthe end of a piston rod 44. The piston rod 44 is slidable in a cylinder45, which is pivotally mounted by a pivot pin 46 between lugs 47 fastened to the side arm 20. The piston rod 44 and the cylinder 45 consitutea hydraulic adjusting member48.The pivotal shaft 42 is supported on both sides of the bearing 43 by supporting arms 49, the intermediate arms 40 being situated between the arms 49 and the bearing 43. The supporting arms 49 are pivotally connected by pivot pins 50 to lugs 41 fastened to the side arm 20.The pins 32,40,42 and 50 constitute the corners of a quadrilateral linkage, in which the pins 32 and 50 are fixed relatively to the carrier 1.

Theworking member3ismovableaboutthepivotal axis 4 and is connected to the side arm 20 by a coupling arm 55. The working member3 is disposed behind the carrier 1 with respectto the direction V. The coupling arm 55 has bearing sleeves 56 and 57 which are disposed one on each side ofthe lug 31. The sleeve 56 is longerthan the sleeve 57 and is situated to the rearofthe arm 20. The bearing sleeves 56 and 57 have adjusting arms 58 and 59, which are connected together by a tie plate 60. The tie plate 60 establishes a connection beween the bearing sleeves 56 and 57. The coupling arm 55 is rotatable aboutthe pivot pin 32 and is rigidly secured to a frame 61 of the working member 3, which is similarto the working member 2. The centreline 28 ofthe member 3 intersects the pivotal axis 4.

The length 62 of the member3 is about one-and-ahalftimes the length 63 ofthe working member 2. The length 62 ofthe working member 3, in the illustrated embodiment, is about 150 cms. The working member 3 comprises clappers which are rotatable on a shaft so that their ends move around a cylindrical surface 64. A protective hood 65 is disposed around the clappers and is fastened to the frame 61. The diameter ofthe cylindrical surface 64 is equal to the diameter of the cylindrical surface 35. A hydraulic adjusting member 67, corresponding with the hydraulic adjusting member48, is connected to the adjusting arms 58 and 59 by a pivotal shaft 60. The member 67 is mounted on the arm 20 in the same manner as the hydraulic member 48.The two working members 2 and 3 are provided with hydraulic motors 69 and 70 respectively, which are connected by supply ducts 71 (not shown com pletely) to the outlet 72 of a pump 73. The pump 73 is mounted on the coupling means 5 and connected by a duct 74to a fluid reservoir 75 supported bythe coupling means. The motors 69 and 70 are provided with outlet ducts 76 (not shown completely), which are connected to an inlet 77 of the reservoir 75.

For use, the hedge cutter is hitched bythe coupling means 5 to the three-point lifting device of the tractor.

The hedge cuttercan thus be readily deployed. The pump 73 can be connected to the powertake-offshaft ofthetractorin a mannerwhich is not shown in detail.

The carrier 1 then extends parallel to a plane at right angles to the direction V, and the pivotal shafts 18,19 and 4 are parallel to the direction V.

In this embodiment the working members 2 and 3 comprise clapper mowers rotated bythe hydromotors 69 and 70. The working members 2 and 3 can then be used to mow ortrim shrubs, hedges or other plants. In the embodiment shown in Figure 1, the working members 2 and 3 are at an angle of 90" to each other so thatthe working member 2 works the top and the working member 3 works the side of a hedge 78.

However, the working members 2 and 3 may be at different angles to each other for working faces which adjoin each other at different angles. The members 2 and 3 can be held in the desired position relativelyto the side arm 20 by the hydraulic adjusting members 48 and 67. These hydraulic adjusting members 48 and 67 can be actuated hydraulically by mechanisms which are not shown in detail. The actuation may be carried outfrom the tractor if the cylinders of the hydraulic members are connected by ducts 79 (not shown in detail) to,forexample, the pump 73 orthe hydraulic circuit of the tractor 6 to which the hedge cutter is attached.The adjusting members 48 and 67 can be actuated independently of each other so that the working members 2 and 3 can be turned independently of each other about the pivotal axis 4 and be fixed at will in any one of a plurality of positions relative to the carrier 1. The quadrilateral linkage comprising the pins 32 (axis 4)40,42 and 50 provides the desired adjustability forthe working member 2 without the member48 being jammed against the arm 20. The positions of the working members 2 and 3 with respect to the tractor can also be changed by turning the carrier 1 with respect to the tractor about the pivotal shaft 18 and/or byturning the side arm 20 with respect to the main arm 17 aboutthe pivotal shaft 19. The carrier 1 then moves parallel to a plane at right angles to the direction V.These operations can be performed by means ofthe hydraulic adjusting members 21 and 24 respectively. These adjusting members can also be actuated by means of a control member arranged, for example, in the tractor and they can be supplied from the pump 73 or the hydraulic system ofthetractor, in which casethe hydraulic members 21 and 24 can be coupled through ducts 79 (not shown in detail) with the fluid circuit concerned.

Because two working members 2 and 3 are provided on the carrier. various tasks can be more readily performed, For example, the hedge 78 can be worked both on the top and on the sides in a single pass as is illustrated in Figure 1. Sincetheworking members can be adjusted independently of each other with respect to the carrier, the working members may be arranged parallel to one another as is shown in Fgiure 4. In this configuration, the working member 2 operates in line with the working member 3, as viewed from behind, and so a high hedge can be worked on one side in a single pass. The two working members then have an overall working length of about 220 cms. The separate adjustment of the working members 2 and 3 is in patricularfacilitated because, one working member is ahead of the other, with respectto the direction V.The full width 52 of the working member 2 is in front of the member 3. The member 3 has the same width 52. The member 2 is ahead of the member 3 by a distance 53 which exceeds the width 52 and, in the illustrated embodiment, is about 1.7-times the width 52. The distance 68 between the members 2 and 3 exceeds the width 54 ofthe arm 20.

The working members 2 and 3 can be used for working low crops orvegetation, for example by mowing grass. Forthis purpose, the working members can be set in the position shown in Figure 5, in which the working members are disposed parallel to and nearthe ground. When a sloping surface to one side ofthe tractor is to be mown, the mowing members can be positioned parallel to the sloping surface. Itwill be obvious that operation of the hydraulic adjusting members 21, 24, 48 and/or 57 can puttheworking members into a large numberof positions with respect to the tractor, the horizontal, and each other. Forthis purpose the disposition of the arm 26 shown in Figure 1 is chosen so that the end of the arm 20 can be brought close to the ground with the arms 20 and 17almostin linewith each other.

Although in the embodiment described above the working members 2 and 3 comprise high-speed clapper mowing members, they maytake different forms. For mowing purposes, members otherthan clapper mowers may be mounted on the carrier 1. By arranging the working members one on each side of the carrier 20, asshown in Figure 2,the construction fastening the working members to the carrier can be advantageous.

In the illustrated embodiment, the length 62 of the working member3 exceeds the length 63 of the working member 2, but the working members may have other lengths and working widths. Also, the illustrated embodiment comprises two clapper mowers mounted on the carrier, but alternatively it is possibleforthereto be two working members onthe carrier which are different from each other. In the embodiment described above, the working members 2 and 3 are hydraulically driven. In principle, however, it is possible to provide other types of drive forthe working members on the carrier 1.

Figures 6 and 7 show a second embodiment of a hedge cutterwhich comprises a carrier 81 on which working members 87, 88 and 89 are arranged. The carrier 81 comprises coupling means 5, similarto the coupling means 5 of the first embodiment, for hitching the hedge cuttertothethree-point lifting device of a tractor. In Figures 6 and 7, parts which correspond to parts shown in Figures 1 to3aredesignated bythe same reference numerals. Like the carrer 1 the carrier 82 comprises a main arm and a side arm; the main arm 17 and its connection with the coupling means 5 correspond with those of the first embodiment and are therefore designated by the same reference numerals.

The side arm 82 ofthe carrier 81 corresponds to the side arm 20 and is connected like the side arm 20 to the main arm 17 by a hinge and an adjusting member.

Again, corresponding parts are designated by the same reference numerals.

Aframe 84 is connected to the side arm by a pivotal shaft 83. The frame 84 comprises two orthogonal adjusting arms 85 and 86. Aworking member 87 comprises a supporting beam 90 which is pivotally connected to the adjusting arm 86 by a pivotal shaft 91. The working member 87 can be fixed by a locking mechanism 92 at will in any one of a plurality of positions relative to the arm 86. A rocking arm 94 is pivotally connected to the end oftheframe arm 85 by a pivotal shaft 93. The rocking arm 94 can be fixed with respectto the adjusting arm 85 at will in any one of a plurality of positions by means of a locking mechanism 95. The rocking arm 94 extends to both sides of the shaft 93 oversubstantially equal distances.The ends ofthe rocking arm 94 are provided with arms 96 and 97 on which working members 88 and 89 are pivotally mounted so that these working members can turn about pivotal axes 100 and 101 forming the centre lines ofthe arms 96 and 97. Each oftheworking members 88 and 89 can befixed at will in any one of a plurality of positions relative to the arms 96 and 97 respectively by means of locking mechanisms 98 and 99. The locking mechanisms 92,95,98 and 99 are generally identical to each other and will be described with referencetothe locking mechanism 95 which comprises a locking plate 102 on the pivotal shaft 93.

The locking plate 102 has a plurality of holes 103. The locking plate is secured to one of the relatively pivotable parts, and a locking arm 104 is provided on the other part and is provided with a locking pin 105, which can be inserted optionally into any one ofthe holes 103 so as to fix the members concerned in the desired relative positions.

The frame 84 can be turned relatively to the side arm 82 aboutthe pivotal shaft 83 by means of a hydraulic adjusting member 108 comprising a cylinder 109 and a piston rod 110. The cylinder 109 is mounted bya pivotal shaft 111 between lugs 112 which are rigidly secured to the side arm, and the piston rod 110 is connected by a pivotal shaft 113 between lugs 114 secured to the frame 114. The side arm 82 comprises two parts 115and 116.The partl 15,onwhichthelugs 112 and the pivotal shaft 83 are provided, can turn with respectto the part 116. The parts 115 and 116 are in line with each other and are relatively pivotable about the centre line 117 of the side arm 82. The pivotal axis 117, like the carrier 81 as a whole, extends transversely ofthe direction V.

Forturning the part 116, it is provided with lugs 119, to which a hydraulic adjusting member 118 is pivoted by means of a pivotal shaft 120. The hydraulic adjusting member 118 is pivotally connected by a pivotal shaft 121 to an arm 122, which is rigidly secured to the part 115. The adjusting members 108 and 118, like the members 48 and 67, are connected to a control mechanism which can be situated in the tractor 6 and is supplied from the hydraulic system of the tractor or from the pump 73.

When the device is put into operation, it is hitched bythe coupling means 5 to the three-point lifting device ofthetractor6 in a mannersimilarto that described forthe first embodiment. The pump 73 can be coupled with the power take-off shaft of the tractor.

The main arm 17 can be turned with respect to the coupling means into the desired position about the pivotal shaft 18 by means of a hydraulic member 21, and the side arm 82 can beturned into the desired position relative to the main arm 17 about the pivotal shaft 19 by means ofthe adjusting member 24. In this waythe pivotal shaft 83 and hence the working members 87,88 and 89 can be positioned at the desired distance from the tractor. The working members 87,88 and 89 can furthermore be adjusted by turning theframe 84, using the adjusting member 108, in the desired mannerwith respectto the side arm 82.

The working members can also be turned by hand with respectto the frame arms 85 and 86 respectively aboutthe pivotal shaft 91 orthe pivotal axes 100 and 101. Thevarious parts can be fixed in the desired positions by the locking mechanisms 92,95,98 and 99.

As is shown byway of example in Figure 6 the two working members 88 and 89 may be at an angle to each other and at an angle of approximately 90" to the working member 87. With this configuration, for example, the top of a hedge can be cut by the members 88 and 89, and one side face ofthe hedge can be worked by the working member 87. It will be obviousthatthe many possibilities of adjustment enabletheworking members to be moved into many other positions relative to one another, to the carrying arm and to the tractor 6. To make it easierto turn the members manually about the pivotal axes 91, 100 and 101 it is preferableforthe centres of gravity ofthese members to be neartheir respective pivotal axes.This also results in lower loads on the respective locking mechanisms 92,95,98 and 99. In the embodiment of Figures 6 and 7, as in the embodiment of Figures 1 to 5, the working members 87,88 and 89 are clapper mowers. The working members 87,88 and 89 may, however, take otherforms, and they may not all be the same as each other. The working members 87,88 have equal lengths 107, which are about halfthe length 106 ofthe member 87. The members 88 and 89 have a total weight approximately equal to the weight ofthe member87. This is advantageous for balancing the frame 84. The lengths ofthe members may be chosen otherwise. In this embodimentthe members87,88 and 89 have an overall length of about 270 cms.

Theworking members 87,88 and 89, like those of the preceding embodiment, are hydraulically driven and are providedforthis purpose with hydraulic motors 123, 124 and 125 respectively. As in the preceding embodiment, these motors can be supplied bythe pump 73, the desired connections between the pump and the motors being made by flexible hoses extending along the carrier and other parts. As in the preceding embodiment the motors may be provided with inlet and outlet ducts 71 and 76 respectively. The members87, 88 and 89 can be readily turned with respect to one another because, as viewed in the normal direction oftravel V, they are relatively off-set in the direction 8 over a distance which is at least equal to their width 52.Itwill be obvious that in accordance with the desired relative movabilities the working members may be grouped otherwise than is shown in Figu res 6 and 7, where the working member87is behind the carrier 81 and the working members 88 and 89 in front ofthe carrier.

Owing to the possible adjustment ofthe working members about the pivotal shafts by which they are connected to the side arm, they can be moved into many configurations. Figures 8,9 and 1 Oshowthree examples. As shown in Figure 8 the working members are arranged in line, as viewed in the direction V,so that they can work, for example, one side of a high hedge 26. In Figure 9 the working members 87 and 88 are in line with one another, as viewed in the direction V, butthe member 89 is at right angles to them for working, for example, both the side and the top ofthe hedge 126. Figure 10 shows a configuration in which the three working members are in line with one another, as viewed in the direction of movement, for working crop on the ground.The form of the working members will be determined in accordance with the tasks to be performed.

The potential positions of the various working members can furthermore be adjusted byturning the part 1 1 5 of the arm 82 with respect to the part 1 1 6 aboutthe pivotal shaft 117. For this purpose the hydraulic adjusting member 118 can be used. This feature may also be used in the embodiment of Figures 1 to 5.

By arranging a plurality of working members on the carrier81 the hedge cutter can be employed very economically, since several working members can operate simultaneously in a single pass. The working members fastened to the carrier 81 need not all be of the same design; they may be differentfrom one another so that different jobs can be carried out in a single pass.

Whilst various features of the hedge cutters that have been described, and that are illustrated in the drawings, will besetforth inthefollowing claims as inventive features, it is to be noted that the invention is not necessarily limited to these features and that it encompasses all of the features that have been described both individually and in various combinations.

Claims

1. Amachineforperforming operations on vegetation, comprising at least two drivable working members which are mounted on a carrierfor movement between at least two positions at different vertical levels, the inclination oftheworking members with respect to each other being adjustable.

2. A machine as claimed in claim 1, in which the working members are adjustable independently of each otherwith respectto the carrier and are optionallyfixable in any one of at leasttwo different positions relative to the carrier.

3. A machine as claimed in claim 1 or 2, in which at least one ofthe working members is mounted on the carrier for pivotable movement.

4. A machine as claimed in claim 3, in which the axis of the pivotal movement is substantially parallel to a vertical plane extending in the normal direction of operative travel ofthe machine.

5. A machine as claimed in claim 4, in which the axis of the pivotal movement is substantially parallel to the normal direction of operative travel of the machine.

6. A machine as claimed in any one ofthe preceding claims, in which one ofthe working members is situated ahead of the other, or another, one ofthe working members, with respect to the direction of operative travel of the machine.

7. Amachineforperforming operations on vegetation, comprising atleasttwodrivableworking members disposed one ahead ofthe other, with respect to the normal direction of operative travel of the machine,theworking members being mounted on a carrierfor movement between at least two positions at different vertical levels.

8. A machine as claimed in claim 6 or7, in which the leading working member leads the trailing working member by a distance which is not less than the width ofthe leading working member measured in the normal direction of operative travel.

9. A machine as claimed in any one ofthe preceding claims, in which the carrierextendstrans- versely ofthe normal direction of operative travel, at least one ofthe working members being in front of and at least one of the working membrs being behind the carrier.

10. A machine as claimed in any one of the preceding claims, in which the working members, or two of them, are pivotally mounted on the carrierfor movement about a common pivotal axis.

11. A machine as claimed in claim 10, in which the carrier comprises a side arm which is provided at one end with two spaced lugs supporting a pivot pin on which the two working members are mounted.

12. A machine as claimed in claim 10 or 11, in which the carrier is provided with two adjacent hydraulic adjusting members are each pivotally connected at one end to the carrier and connected at the other end to a respective one ofthe working members in a manner such thattheworking members are independently adjustable with respect to the carrier by means ofthe adjusting members and are optionally fixable in any one of at least two different positions.

13. A machine as claimed in claim 12, in which at least one of the adjusting members is connected to the respective working member by means of a quadrilateral linkage, of which two pivotal axes are fixed with respect to the carrier

14. A machine as claimed in any one of claims 1 to 10, in which the working members, or at leasttwo of them, are mounted on a frame which is pivotally connected to the carrier.

15. A machine as claimed in claim 14, in which the frame is movable with respect to the carrier by means of a hydraulic adjusting member and is optionally fixable in any one of at least two different positions.

16. A machine as claimed in claim 14or 15, in which the frame comprises two frame arms which are at an angleto one another, on each of which is arranged at least one ofthe working members.

17. A machine as claimed in claim 16, in which the working members are pivotally mounted on the respective frame arms and can each be fixed optionally in any oneofat least two different positions with respect to the frame arms.

18. Amachineas claimed in any one of claims 15 to 17, in which a rocking arm is pivotally connected to one of the frame arms, at least two of the working members being connected to the rocking arm.

19. A machine as claimed in claim 18, in which the rocking arm is pivotally mounted, substantially at its centre, on the frame arm, the working members being pivotally mounted at the ends of the rocking arm and being fixable in at least one of at least two different positions relative to the rocking arm.

20. A machine as claimed in claim 18or 19, in which the otherframe arm is provided with a single one ofthe working members which is iarger than at least one ofthe otherworking members.

21. A machine as claimed in any one of claims 14 to 20, in which the total weight of two of the working members is substantially equal to the weight of a third one ofthe working members.

22. A machine as claimed in any one of claims 14 to 21, in which the frame extends substantially parallel to a plane at right angles to the normal direction of operative travel of the machine, two ofthe working members being in front ofthe frame, with respect to the normal direction of pperative travel, and a third one oftheworking members being behind the frame.

23. A machine as claimed in any one of the preceding claims, in which the working members are mounted on the carrier for adjustment about a pivotal axis extending substantiallytransversely of the normal direction of operative travel ofthe machine.

24. A machine as claimed in claim 23, in which hydraulic means is provided for adjusting the working members about the transverse pivotal axis.

25. A machine as claimed in claim 23 or 24, in which the working members are mounted on a part of a side arm of the carrier, which part is pivotable about the transverse pivotal axis with respectto the rest of the side arm, the parts of the side arm being in line with each other.

26. A machine as claimed in any one of the preceding claims, in which the carrier comprises a main arm and a side arm which is pivotable with respectto the main arm and is fixable in any one of a plurality of positions, the working members being mounted on the side arm and the main arm being provided with coupling means for hitching the machineto a tractor or a similarvehicle.

27. A machine as claimed in claim 26, in which the main arm is connected to the coupling means so asto be pivotable about an axis extending in the normal direction of operative travel ofthe machine.

28. A machine as claimed in any one of the preceding claims, in which the working members are hydraulically drivable and are each provided with a hydraulic motor connectedto apump.

29. A machine as claimed in any one of the preceding claims, in which the working members are mowing members.

30. A machine as claimed in claim 29, in which the mowing members are clapper mowers.

31. A machine as claimed in claim 30, in which the clappers are mounted on a rapidly rotating shaft.

32. A machine as claimed in any one of the preceding claims, in which the working members can be disposed so thatthetop and a side of a hedge can be worked simultaneously.

33. A machine as claimed in any one ofthe preceding claims, in which the working members, or at least one of them, can be disposed parallel to one 2notherso that they can work the same surface.

34. A machine as claimed in any one of the preceding claims, in which at least one of the working members is manually adjustable with respect to the carrier and can be fixed atwill in any one of a plurality of positions.

35. A machine as claimed in any one of the preceding claims, in which at least one ofthe working members can be turned about a pivotal axis passing substantially through the centre of gravity of that working member.

36. A machine as claimed in any one of the preceding claims, in which the working members have an overall working width of about2.70 metres.

37. A machine as claimed in any one of the preceding claims, in which coupling means is provided for hitching the machine to the lifting device of a tractorora similar vehicle.

38. A machine as claimed in any one of the preceding claims, in which the carriercomprisestwo relatively movable arms which are fixable at will in any one of at least two different positions relative to each other.

39. A machine as claimed in any one of the preceding claims, which is a hedge cutter.

40. A hedge cutter substantially as described herein with reference to, and as illustrated in Figures 1 to 5 or Figures 6to 8 of the accompanying drawings.