GB2179534A - A mowing machine - Google Patents

Abstract

A mowing machine comprises a rotary cutting unit (8) mounted on a shaft (37) which is supported in a drive unit (33). On the side away from the drive unit (33), the cutting unit (8) has a flexible covering hood (93) having embossed parts (97) which protect the upper ends of fastening means (79) securing a cutter (10) to the cutting unit (8). <IMAGE>

Description

1 GB 2 179 534 A 1

SPECIFICATION

A mowing machine This invention relates to a mowing mach ine, pa rticularly, although not exclusively, for agricultural purposes.

According to the present invention, there is provided a mowing machine comprising at least one cutting unitwhich is supported in a support so as to be rotatable about an upstanding rotary axis, the cutting unit being provided on the side away from the support with a flexible covering hood.

The flexible covering hood can deflect obstacles or the like encountered by the cutting unit. The flexible covering hood can at least partly abosrb the force produced by impact on an obstacle so thatthe risk of damage of the cutting unit or other parts of the mower isreduced.

Fora 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 1 is a plan view of a mowing machine hitched to a tractor; Figure 2 is an enlarged vertical sectional view of a cutting unit of the machine of Figure 1; Figure 3 shows part of Figure 2 on an enlarged scale; and Figure 4 is a plan view of the cutting unit of Figure 2.

As shown in Figure 1, the mowing machine has a hitch 3 which is attached to the three-point lifting device 1 of a tractor 2. An intermediate frame4 is mounted on the rear of the hitch 3 and is pivotable with respect to the hitch 3 about a substantially 100 horizontal pivot axis 5 extending in the intended direction of travel of the mowing machine, indicated by an arrow A. In the illustrated embodiment the axis 5 is located approximately in the vertical longitudinal central plane of the tractor 2. The intermediate frame 4 105 extends, during operation, from the axis 5 mainly towards a lateral boundary plane 28 of the tractor 2, parallel to the direction A, and thus extends transversely of the direction A.

A main frame 6 is mounted on the end of the 110 intermediate frame 4 nearer the side of the tractor 2for pivotal movementwith respect to the intermediate frame 4 about a pivotal axis 7. The axis 7 is parallel to the axis 5 and is a short distance inside the boundary plane 28. Viewed on plan, the main frame 6 is in line with the intermediate frame 4 and therefore also extends transversley of the direction A.

In the embodiment shown in Figure 1, the main f rame 6 carries six cutting units 8, which can be driven about upwardly extending rotary axes 9. The rotary axes 9 may be vertical, but preferably, during operation, they are slightly forwardly inclined from bottom to top. Each cutting unit is provided at its circumference with one or more cutters 10 (there are two in the illustrated embodiment). The ends of the cutters 10 of the cutting unit nearestthe intermediate frame 4 describe a circle, during operation, which extends close to the boundary plane 28.

The intermediate frame 4 and the main frame 6 are pivotable with respectto the hitch 3 about an 130 upwardly extending axis 11 located at least approximateiy in thevertical central plane of the tractor 2 and connecting the intermediate frame 4with the hitch 3. In normal operation, turning aboutthe pivotal shaft 11 is prevented by a known shear bolt mechanism 12, which is disposed away from the vertical central plane of thetractor and connects the intermediate frame 4 with the hitch 3.

Above the main frame 6there is a framework 13, the periphery of which is provided with flexible walls extending down to the g round for intercepting objects such as stones and the like thrown up by the cutters during operation, so as to retain them inside the flexible hood around theframework 13.

An auxiliary shaft 14 is connected between a power take-off shaft of the tractor 2 and an input shaft 16 of the mower. The shaft 16 is arranged in a sleeve 15 which is rigidly secured to the intermediate frame 4 and extends substantially horizontally in the direction A. The centreline of the input shaft 16 journalled in the sleeve 14 coincideswith the axis 5.The input shaft 16 projects from the rear of the sleeve 15, the projecting portion carrying a pulley 17. Nearthe end of the intermediate frame 4 nearerthe main frame 6 there is a pulley 18which is mounted on a shaft 19. The shaft 19 isjournalled on the one hand in lugs 20 and 21 provided on theframe 4 and on the other hand in a gear box22, which is pivotable with respectto the lugs 20 and 21 and is located between them. The gear box 22 is rigidly secured to the main frame 6. The centreline of the shaft 19 coincides with the axis 7. The pulley 17 is drivably connected with the pulley 18 by at least one V-belt 23, which runs around the two pulleys and is located behind the intermediate frame 4with respectto the direction A. The shaft 19 of the pulley 18 carries a bevel gear wheel 27, which is in the gear box 22 and meshes with a bevel gearwheel 25 whose rotary axis is approximately horizontal in operation and intersects the axis 7 substantially at right angles. The shaft of the gear wheel 25 is journailed in a substantially vertical extending gear box 26, which is rigidly secured to the gear box 22 and fastened atthe lower end to the main frame 6. The shaft of the bevel gear wheel 25 is provided with a gear wheel 27 located inside the gear box 26 and coupled through one or more intermediate gearwheels (not shown) with a gearwheel (not shown) fastened to a main drive shaft 31 journalled in the main f rame 6. The main frame 6 fastened to the underside of the gear box 26 is made up of intermediate pieces 32 and drive units 33, which are alternately arranged and interconnected by a tie rod 34. The intermediate pieces 32 and the drive units 33 are respectively substantially indentical to each other. They are cast components which together make up a hollow beam constituting the main frame 6 in which the main drive shaft 31 and the tie rod 34 are accommodated. The tie rod 34 draws the intermediate pieces a nd drive units towa rds one another and secu res them to the 1 ower end of the gea r box 26. The intermediate pieces a nd d rive u nits together with the tie rod constitute a bend i ng-resista nt un it of the mai n frame beam 6 carrying the cutting units 8 and their drive g ear.

Fig u re 2 shows in detail a vertical sectional view of one of the drive u nits 33. The section is taken in a plane 2 parallel to the length of the beam 6 and includes the axis g of the cutting unit. The drive unit shown is clamped between two intermediate pieces 32. As is shown in Figure 2, the main drive shaft 31 extends through the intermediate pieces and the drive unit. 70 The main drive shaft 31 may have any desired shape so that it can be drivably coupled with a bevel gear wheel 35, which has a bore matching the shape of the drive shaft 31 for rotatably coupling the gearwheel 35 with the main drive shaft 31. In this embodiment the 75 main drive shaft31 has a square section and is located in a square, uninterrupted hole in the bevel gearwheel 35,which holefits around the shaft31. The bevel gear wheel 35 is in mesh with a bevel gearwheel 36,the centre line of which coincidesw[th theaxis 9 and 80 intersects the centre line of the bevel gearwheel 35 and the drive shaft 31 at right angles. The gearwheel 36hasan upwardly extending shaft 37 on which the cutting unit 8 is mounted. The shaft 37 hasacytindricai part38,which is a closefit inside inner races 39 and 40 85 of a compact bearing 41. The part 38 covers the whole heightof the race 39 and part of the heightof the race 40. The compact bearing 41 has only one outer race 42, which supports two rows of balls 44 and 45 and which fits in a bearing housing constituted by a retaining ring 90 43.The inner races 39 and 40 are independently movable relativelyto each other and bearon the outer race42 bythe rows of balls 44 and 45 respectively. The rows of balls44 and45 are arranged in independent cages46 and 47. The inner race 39 bearsatand end 95 face on a supporting shoulder48 of the bevel gear wheel 36,whereasthe outer race 42 bears at its opposite end on a supporting shoulder49 of the retaining ring 43.The rows of balls 44 and 45 are each located between contact surfaces of the outer race and 100 the respective inner races 39 and 40 which are at an angle 50 which exceeds Wand is in this embodiment about Wto a plane normal to the rotary axis 9. The retaining ring 43 isfastened by bolts 51 to the top of a housing 52 of the drive unit 33. The retaining ring 43 is provided with locating recesses 53 for centering the ring 43 with respect to the axis 9. The retaining ring 43 and the housing 52 are castings, and the retaining ring 43formsa lid on the housing 52.

Above the cylindrical part 38 on the shaft 37 there is 110 a splined part 56, on which a carrying ring 57 is mounted for rotation with the shaft 37. The lower end of the ring 57 is centered on the inner surface of the inner race 40 of the bearing 41. The upper surface 59 of the ring 57 is located above the splined part 56 and 115 provides a projecting boss having a non-circular outer peripherywhich locates in an opening 61 of a cutter carrier62.

The cutter carrier 62 is in theform of a strip and is clamped againstthe carrying ring 57 by a clamping ring 63 and a nut64 on the shaft37. The nut 64 is preventedfrom turning aboutthe shaft37 by a pin 65.

The cuttercarrier 62 mainly constitutesthe carrying memberof the cutter unit 8 and carriesthe cutters 10.

In the shaft37 there is a vent channel 70. The vent channel 70 hastwo parts71 and 72, which are at an angleto oneanotherof about90'in this embodiment. Both ofthe parts71 and 72 are inclined to the rotary axis 9. The vent channel 70 extends between the interior of the housing 52 and the splines 56 so that the 130 GB 2 179 534 A 2 interiorof the housing 52 belowthe retaining ring 43 is in open communication with the atmosphere. The interiorof the housing 52 is otherwise a closed space in which the bevel gearwheels 35 and 36 are accommodated. The interior of the housing 52 is closed bythe retaining ring 53, the shaft 37 and the bearing 41. The gaps between the outer race 42 and the inner races 39 and 40 are closed near the ends of the bearing 41 by closing rings 66 provided in the ends of the bearing 41 on opposite sides of the two rows of balls44and45.

The gearwheel 35 is journalled in a bearing 75, the outer race of which is supported in a bore 78 of the cast housing 52. This bore 78 also receives a centering ring 76 which projects beyond the end face of the housing 52 and engages a centering bore which projects beyond the end face of the housing 52 and engages a centering bore of the adjacent intermediate piece 32. Between the bearing 75 and the centering ring 76 there is a retaining ring 77 which engages a groove in th6 bore 78. A sealing ring, for example an 0-ring, may be provided, if desired between the outer race of the bearing 75 and the bore 78. The gearwheel 35 is integral with a sleeve 35A extending awayfrom the gearwheel towards the other side of the housing 52 where it isjournalled in another bearing 75 in the housing corresponding with the bearing 75 adjacent the gearwheel 35. The side of the housing 52 is also centered by a centering ring 76with respectto the neighbouring intermediate piece 32 and closed towardsthe hollowspace of said intermediate piece by a retaining ring 77. The space insidethe housing 52thus forms a closed spacethat can befilied with grease or other lubricantforthe gearwheels. The continuous opening in the gearwheel 35 and the sleeve35A, through which extendsthe shaft31, does not essentially constitute part of said closed space.

The cutting unit8 comprises a cuttercarrier62 formed in this embodiment by a strip bent in a plane shown in Figure 2, but it may be formed in a different manner provided that it can carry the cutter 10 and establish a connection between the cutters 10 and the shaft37. The cutters 10 are connected to the cutter carrier 62, as is shown in Figure 2, by a fastening memberformed by a bolt 79. The bolt 79 is arranged nearthe end of the cutter carrier and has a boss 80 aboutwhich the cutter 10 is rotatable. The cutter 10 has an opening 81 in which the boss 80 is located. The top part of the boss 80 is located in a recess 82 of a coupling member83. The depth of the recess 82 is such thatthe space between the underside of the coupling member 83 and a head 84 of the bolt79 is large enough to enable the cutter 10 to rotate freely aboutthe boss 80. The coupling member 83 also has an opening communicating with the recess 82, through which the bolt 79 extends into an opening 90 in the cutter carrier 62, to which the bolt is fastened by a nut 85. The boss 80 is eccentric with respectto the centre line 86 of the bolt 79 so thatturning of the boss 80 and the bolt 79 with respectto the cutter carrier 62 and the coupling member 83 is prevented. The nut 85 and the boss 80 clamp the coupling member 83 tightly to the cutter carrier 62. The coupling member 83 has a hub 87 which partly projects above the strip-shaped part of the member 83 and is located in an opening 88 f t 3 1 GB 2 179 534 A 3 of the cuttercarrier 62.The hub 87 isfastenedto the cuttercarrier bya bolt94. The hub extends belowthe rest of the member83 and this downwardly projecting partforms a stop 89forthe cutter 10. The openings 88 and 90are spaced apart, but preferably, as in this embodiment, their centre lines are located on a line extending radiallyof the rotary axis 9.

The cutting unit 8 has a covering hood 93,which is fastened-as is shown in Figure 2-bythe bolts 79to the cutter carrier 62. The hood 93 is clamped tight between thetop surface of the cuttercarrier62 andthe nut85. The hood is also secured tothe cuttercarrier 62 bythe bolts 94, which are screwed intotapped holes in the hubs 87 of the coupling members 83.The covering hood 93 has a curved, central part95 which extends overthe nut 64 and the shaft 37. Atthe periphery of the central part95 isformed a bead 96which engageswith a closefitaround the clamping ring 63. Belowthe bead 96the hood has a downwardly diverging conical part which is inclined to the axis 9 bythe same angle asthe conical parts of the cuttercarrier 62 in Figure 2. The hood 93 isformed with protective walls 97 extending around the nut85 and thetop end of the bolt79 in a mannersuch thatthetop end of the bolt79 does not project abovethetop of its protectivewall 97. Viewed on plan, each protective wall 97 extendsthrough 180' aboutthe axis 86 and then has straight portions extending to the periphery of t he hood 93. Atthe periphery, the hood has a downwardly bent over rim 98, which extends at least as far as a plane going 95 through the underside of the cutter carrier 62. In this emodiment each cutting unit 8 has two diametrically opposite cutters 10. At the circumference between the cutters 10 the hood 93 has upwardly offset portions 99.

For operation, the mowing machine is coupled with 100 the tractor as shown in Figure 1. The cutting units 8 are rotated abouttheir rotary axes 9 by drive transmitted through the transmission members shown from the auxiliary shaft 14. The shaft 14 drives the main shaft 31 via the V-belt 23 and the gearwheels in the housing 22 105 and 26. The main shaft31 extends throughout the length of the mainframe 6 and drives each of the shafts 37 in the driving units 33. The direction of rotation of the cutting units aboutthe rotary axis 9 may be chosen by arranging the respective gearwheel 35 110 on the left- or right-hand side of the rotary axis 9 as viewedin Figure 2. In this waythe row of cutting units can be driven in the desired relative directions of rotation. 50 Each of the cutting units is effectively jou rna 1 led by its shaft 37 in the drive unit 33 concerned, the bearing 41 constituting a satisfactory support for the shaft 37 in the drive unit 33. The bearings 41 can befittedeasily and provide a support over a comparatively great height owing to the length of the bearings each having two spaces rows of balls. Nevertheless, the bearings are compact and occupy little space in the drive unit, which can thus be as small as possible. The contact angle of the balls with respectto the recess of about 30', the contact angles of the two rows of balls being directed in opposite senses, supports the cutting unit in a manner such that forces exerted thereon from different directions can be satisfactorily absorbed. The cutting unit may be loaded in strongly varying ways, particularly when striking obstacles in unexpected 130 directions. All of these forces can be satisfactorily met bythe construction shown of the bearing 41. The separate races39 and 40 may be advantageous, in particular, because loads resulting from impactwith obstacles are usually eccentricwith respecttothe shaft 37. Since the bearing 41 is an integral unit, it can be readily fitted, and setting errors and the like will practically not occur. Owing to the locations of the contact angles 50 the bearing can abosrb both radial and axial forces in both directions. Since fewer errors will be made in mounting the bearing 41 in the drive unit33, the risk of defects in the drive unit dueto such errors is practically nil. Maintenance work on the machine is thus reduced and the minor risk of defects results in a reduced risk of breakdown which could cause fragments of the machine (in particularfrom high-speed cutting units) to be swept around and ejected, thus exposing the operator or bystanders to series danger. In particular, cutting units with rotating knives may be dangerous for bystanders when the cutters or other parts are detached as a result of defects.The detached parts may cause heavy damage, sincethe cutting members usuallyturn about their rotary axes at speeds of a fewthousand revlmin, for example 3000 to 5000 revlmin.

Atthese high speeds of rotation of the shafts 37 and the cutting units fastened thereto, thorough lubrication of the components in the driving units 33 is required. Forthis reason, the cutting units are constructed so that the drive-transmitting bevel gear wheels are arranged in the closed interior of the housing 52, which is filled with grease or other lubricants. Because heat is generated inside the closed space, it is necessary for there to be communication between this closed space and the open air, and this is whythe vent channel 70 is provided in the shaft 37. The parts 71 and 72 of thevent channel 70 are located so that they have a radial component with respect to the axis 9. Owing to the high speeds with which the shaft 37 is driven, the parts 71 and 72 of the vent channel will remain free of lubricant. The high rotation speed results in such a high centrifugal force on anything in the channel 70that itwill leavethe vent channel at one of its ends sothatthe channel remains freeto allow airto escapefrom the closed space orto enterthe closed space from the outside. The closed space communicates through the channel part71 opening into thatspace,the channel part72 and the clearance between the splines 56with the space above the end surface 59 andthroughthat space with the open air. It is importantthatthe clamping ring 63 and the cutter carrier62 with the opening 57 should notfit around the part 59 so thatthiswould be hermetically closed.

Although in this embodimentthe bearing has two rows of ball, it may, as an alternative, comprise, for example, two rows of rollers.

The hood 93 constitutes a protective coverforthe parts located below it and has a shape such that itcan deform when heavyforces are exerted on itJor example if unevenesses of the ground are encountered. This deformation will absorb enough of the energy produced bysuch impactto avoid damage to important parts of the cutting unit andlor other parts. In this embodimentthe protective hood 93 is made 4 GB 2 179 534 A 4 from thin sheet material, such as metal, of a thickness of, forexample, 0. 5 mm. Howeverthe protective hood maybe madefrom other material. It maybe made from a material such that itcan deform to absorb energy and subsequently regain its original shape. The hood may be madefrom synthetic materials andlor other more or lessflexible materials suitable forthis purpose. The hood 93 fully covers the cutter carrierand the fastening areas of the cutters on the cutter carrierso that all important parts are protected bythe hood. The walls 97will sufficiently protect the nuts 85 and the bolts 79 during rotation, and the positions of the bolts 94 behind the walls 97 will avoid damageto them. The higher, central part 95 and the conical part of the hood provide a satisfactory path for delivery of the crop mown bythe cutters 10. The walls 97 can also positvely contributeto the delivery of the mown crop during rotation of the cutting unit about its rotary axis in the desired direction. Even the upwardly bent-overparts 99 can play a positive part in delivering the mown crop. The parts 99 are bent upwards to provide a free passage for cutters of adjacent cutting units.

Thestop 89 of the hub 87 serves to arrestthe cutter when it gets belowthe cutter carrierjor example as a result of impactwith an obstacle. The cutter rotatable aboutthe boss 80 can,therefore, notstrike the drive housing. The arm 83 forms a satisfactory, readily mounted supportforthe boss 80 of the cutter.

Although in the embodiment shown in the drawings the axis 9 extends substantiallyvertically,the construction embodying the invention may also be used with a different position forthe axis of the cutting member.

Claims (11)

1. A mowing machine comprising at least one cutting unitwhich is supported in a support so as to be rotatable about an upstanding rotary axis, the cutting unit being provided on the side away from the support with a flexible covering hood.

2. A moving machine as claimed in claim 1, in which the covering hood is at least partly deformable.

3. A mowing machine as claimed in claim 1 or2, in which the covering hood extends at least substantially from the rotary axis of the cutting unit into the proximity of the periphery of the cutting unit.

4. A mowing machine as claimed in anyone of the preceding claims, in which, as viewed in a direction parallel to the rotary axis of the cutting unit, the covering hood is substantially circular.

5. A mowing machine as claimed in anyone of the preceding claims, in which the covering hood covers at least substantially completelythe cutting unit on the side opposite the side of the support.

6. A mowing machine as claimed in anyone of the preceding claims, in which the covering hood is mounted on a cutter carrier.

7. A mowing machine as claimed in claim 6 in which the hood has an embossed part extending at least atthefront side of the top of a fastening member which secures the cutter to the cutter carrier.

8. A mowing machine as claimed in claim 7, in which the covering hood is fastened to the cutter carrier by a bolt comprising the fastening means which secures the cutterto the cutter carrier.

9. A mowing machine as claimed in claim 8, in which the bolt is located between the embossed part and a conical central part of the covering hood.

10. A mowing machine as claimed in anyone of claims 6to 9, in which a cental part of the covering hood extends above a fastened area of the cutter carrierto the shaft of the cutting unit.

11. A mowing machine as claimed in anyone of the preceding claims, in which the cutting unitwith the hood is mounted on a shaft supported in a drive unit, which forms part of the support and is connected with intermediate pieces of the support by a tie rod.

Printed in the United Kingdom for Her Majesty's Stationery Office by the Tweedda[e Press Group, 8817356, 3187 18996. Published at the Patent Office, 25 Southampton Buildings, London WC2A lAY, from which copies may be obtained.

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