AU7243000A - Improved cutter assemblies - Google Patents

Description

1 "IMPROVED CUTTER ASSEMBLIES" This application is associated with our previous Provisional Applications Nos. PK 0561 and PK 2056. This invention relates to improved cutter assemblies. This invention has particular reference to grass cutter assemblies for ride-on lawn mowers and reference will be made hereinafter to such application. It is to be understood however, that this invention could be utilized in other applications, such as in domestic mowers and/or in agricultural equipment for harvesting crops and the like.

Lawn mowers are frequently provided with a height adjustable cutter assembly supported intermediate the front and rear wheels and provided with a side or rear outlet through which cut grass may be discharged. The outlet is frequently adapted o 15 for the connection to a grass catcher.

With reference to ride-on lawn mowers it has been found .*g that a cutter assembly provided with a single rotating cutter assembly of about 82 cm diameter provides optimum performance without sacrificing machine maneuverability. Wide cut machines are available which provide an increased width of cut.

Typically, such machines have ganged cutters supported in side by side relationship within a common cutter housing. While these ganged cutters are effective, they are relatively complicated and expensive to manufacture. Their use also reduces the maneuverability of the machine, as the cutter housing extends outwardly beyond the wheel track of the machine and this prevents the machine being driven through or parked in spaces which would accommodate a machine with a smaller cutter assembly.

Furthermore, the wide cut provided is only necessary for relatively large areas to be cut. As such machines are frequently utilized for mowing relatively small areas the wide cutter head assembly often provides no real advantage and positive disadvantages.

This invention aims to alleviate the above disadvantages and to provide a cutter assembly which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.

With the foregoing and other objects in view, this invention in one aspect resides broadly in a cutter assembly including:- 15 a main cutter assembly including a cutter housing which supports a cutter assembly within said cutter housing, and an auxiliary cutter assembly mounted to said cutter housing and being so positioned that its operative cutting path overlaps the operative cutting path of said main cutter assembly.

o o 20 The overlap may be achieved by placing the main and S•auxiliary cutter assemblies with their cutter spindle axes transversely in line and with the blades of one cutter assembly adapted to overlap with the blades of the other cutter assembly.

This arrangement would require means for synchronizing the rotation of the main and auxiliary cutter assemblies or height displacement therebetween to prevent the clashing of the blades.

Preferably however, the cutting path overlap is achieved by arranging the blades of the respective cutters to terminate short of one another and by displacing the axis of the auxiliary cutter assembly either in leading or trailing the transverse axis of the drive spindle of the main cutter assembly whereby the cutting paths overlap. It is also preferred that the auxiliary cutter assembly be arranged with its discharge port communicating with the main cutter housing whereby grass cut by both cutter assemblies may be discharged through the main discharge chute and thus collected in a single grass catcher. Of course individual outlets may be provided for discharging grass from the respective cutter assemblies. Preferably the discharge opening of the auxiliary cutter housing is discharged into the main cutter 15 housing substantially in line with or trailing the transverse axis of the drive spindle. It is also preferred that the auxiliary cutter assembly be supported at the side of the main cutter assembly which is remote from the discharge of the main cutter assembly.

**Se The main cutter assembly may be provided with power takeoff means associated with the drive spindle and the auxiliary ee.

S•cutter assembly may be driven from the power take-off on the main cutter assembly. The power take-off may include an idler shaft mounted on the cutter housing and a belt drive interconnecting the idler shaft with the cutter spindle of the auxiliary cutter assembly. The idler shaft may be driven from the cutter spindle of the main cutter housing by any suitable means such as chains and sprockets and belts and pulleys, or through gears as desired. Of course the auxiliary cutter assembly may be driven separately from the main cutter assembly.

Preferably the drive arrangement is such that pressure due to air flow generated by rotation of the cutter assembly within the auxiliary cutter housing at the outlet therefrom is greater than the pressure due to air flow generated by rotation of the cutter assembly within the main cutter housing-at the point at which grass is discharged from the auxiliary cutter assembly into the main cutter assembly.

In a preferred arrangement, the radius of the cutting blades in the auxiliary cutter assembly, is approximately one half to five eighth the radius of the cutter blades for the main 15 cutter assembly and the blade tip speed of the auxiliary cutter blades is substantially equal to or greater than the tip speeds S"of the main cutter blades. Furthermore, the auxiliary cutter o assembly may utilise more cutting blades than the main cutter in .order to increase the discharge pressure through the outlet from

S

the auxiliary cutter assembly.

In a preferred form, the auxiliary cutter housing is detachably secured in its operative position and it has an outlet which communicates with an inlet in the side wall of the main cutter housing. A cover may be provided for the inlet to the main cutter housing when the auxiliary cutter assembly is not in use. The auxiliary cutter assembly may be adapted to pivot from its operative position to a stowed position at which it lies substantially within the transverse extremities of the main cutter housing. The action of pivoting the cutter assembly between the operative and stowed positions may cause a cover for the main cutter assembly inlet to be closed automatically. For example a cover supported for movement around the side wall of the main cutter housing may be connected to the pivot linkage supporting the auxiliary cutter and move automatically therewith to its respective positions.

Suitably, there is also provided a cover extending about the belt drive between the main cutter assembly and the auxiliary cutter assembly. The cover may be releasable to enable the auxiliary cutter housing to move from its operative position or it may consist of a number of parts which fold to an operative 15 covering position when the auxiliary cutter assembly is disposed in its operative attitude and pivot away from the cutter assemblies when the auxiliary cutter assembly is in its stowed attitude.

In order that this invention may be more readily oooo understood, and put into practical effect, reference will now be made to the accompanying drawings, wherein Soo...

Fig. 1 is typical illustration of a ride-on mower; Fig. 2 is a diagrammatic plan view of a preferred form of cutter assembly for a rider mower, and Fig. 3 is an end view corresponding to Fig. 1.

The cutter assembly 10 of the present invention includes a 6 main cutter assembly 11 supported between the front steering wheels 8 and rear drive wheels 9 of the ride-on mower 7. The main cutter assembly 11 includes a cutter housing 12 which has an upwardly expanding discharge chute 13 having an outlet 14 which discharges to one side of the cutter housing 12 and cutter blades in any suitable manner supported at the lower end of a drive spindle 27. The upward expansion of the discharge chute 13 commences at a position which is disposed rearwardly of the transverse centre line 15 of the cutter housing 12. The latter is also provided with jockey wheels 16 which engage the ground when the minimum cutting height is selected.

An auxiliary cutter assembly 20 is pivotly attached through brackets 21 to the cutter housing 12 such that the auxiliary cutter assembly 20 may pivot from a stowed position as shown in dotted outline at 22 to its operative position as illustrated. The auxiliary cutter housing is also provided with and cutter blades in any suitable manner supported at th lower end of a drive spindle 31.

The main cutter housing 12 has a peripheral wall 23 which •eg* go 20 has one opening which constitutes the discharge outlet 14 and a second opening as shown in dotted outline at 25 which forms an inlet opening through which grass discharged by the auxiliary cutter assembly 20 may be introduced to the housing 12. For this purpose the cutter blades of the auxiliary cutter assembly 20 are adapted to be driven in the same direction as the cutter blades of the main cutter assembly.

As indicated, the blade shaft 31 of the auxiliary cutter assembly is driven through a belt drive from the main drive spindle 27 of the cutter assembly 10. The path extremities of the cutter blades are shown dotted at The belt drive includes an upstanding idler shaft 28 mounted on the cutter housing 12 and supporting a first pulley which is belt driven from a pulley 38 on the main blade spindle 27. A second pulley 38A is mounted beneath the pulley 38 for connection to the mower's engine in conventional manner. A further pulley 30A is supported beneath the pulley 30 and is adapted to transfer the drive to the spindle 31 of the auxiliary cutter assembly 20. The belts 32 and 33 transfer the drives as illustrated.

The idler shaft 28 is bolted to the cutter housing 12 through an adjustable mounting plate 34. For adjustment purposes, the mounting plate 34 may pivot about an inner mounting bolt 35 and be clamped in an adjusted position by a outer mounting bolt 36 supported in the arcuate slot 37 in the plate 34 and centered on the inner bolt 35. The inner bolt is so positioned that the plate 34 pivots in a direction which adjusts both belts 32 and 33 simultaneously.

•The discharge chute 40 formed on the auxiliary cutter assembly 20 also expands upwardly from the top face of the auxiliary cutter housing 41. The upward expansion of the discharge chute 40 is limited to ensure that its upper face 45 is either level with or below the adjacent upper face 46 of the 8 adjacent portion of the discharge chute 13.

A guard or housing shown dotted at 48 is provided to cover the belt drive. The guard may be either pivotly connected such that it folds out of the way when the auxiliary cutter assembly pivots about the hinges 47 of the brackets 21. Alternatively the guard may be rigid and detachable and adapted to be supported in position by wing-nuts or the like. The auxiliary cutter assembly 20 is locked in position relative to the main cutter assembly 10 by a barrel bolt 42 mounted on the auxiliary cutter housing 20 and engageable with a socket 43 fixed to the cutter assembly 10. The latter is also provided with an aperture in which the barrel bolt 42 may engage when the auxiliary cutter housing is elevated to its stowed position so as to lock it in this stowed position. The hinges 47 may be positioned at any ••go 15 suitable position to provide both adequate ground clearance for the auxiliary housing when stowed and placement inboard of the main housing 12. Belt retaining means may also be provided to :°ooe• slacken at least one belt when the auxiliary cutter housing is raised and to hold the or both slackened belts adjacent their respective pulleys so that upon lowering the auxiliary cutter housing, the belts 32 and 33 will be positioned for operation.

S• In use, the mower may be used with the auxiliary cutter assembly in its stowed position 22. When a wide cut is required such as for maintaining a playing field or the like, the removable cover for the inlet 25 is removed and the cutter housing 41 is pivoted to its operative position, the drive belt 9 33 is then connected and the cover installed to hold the cutter housing 41 rigid with the cutter housing 12. The mower may then be used in conventional manner, with a grass catcher if desired, and of course the normal de-clutching arrangement for the main cutter 10 will also de-clutch the auxiliary cutter 20. Suitably the cutters are driven at a speed such that the tip speed of the main blades is in the order of 9,000 to 11,000 cm/second and the tip speed of the auxiliary blades is about 250 to 350 cm/second faster.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined in the 15 appended claims.

Claims (10)

1. 2. A cutting assembly as claimed in claim 1, wherein said auxiliary cutting assembly is pivotable from an operable position to a stowed position.
2. 3. A cutting assembly as claimed in any one of claims 1 to 3, wherein said auxiliary cutter assembly has its discharge port communicating with said main cutter housing.
3. 4. A cutting assembly as claimed in claim 4, wherein said discharge port is substantially in line with or trailing the transverse axis of said drive spindle. eo
4. 5. A cutting assembly as claimed in any one of claims 1 to 4, wherein said blades rotate about respective substantially vertical axes and wherein the main cutter blades and said auxiliary cutter blades terminate short of one another and the 11 axis of said auxiliary cutter assembly is longitudinally displaced from the axis of rotation of said main cutter blades.
5. 6. A cutting assembly as claimed in claim 5, wherein the radius of said auxiliary cutter blades is from one half to five eighths the radius of said main cutter blades.
6. 7. A cutting assembly as claimed in any one of claims 1 to 6, wherein said auxiliary cutter assembly is supported at the side of said main cutter assembly remote from said discharge port.
7. 8. A cutting assembly as claimed in any one of claims 1 to 7, wherein said auxiliary cutter assembly is driven from the cutter spindle supporting said main cutter blades. :i 9. A cutting assembly as claimed in any one of claims 1 to 8,
8. 9. e *wherein said auxiliary cutter assembly stowed position lies oee o substantially within the transverse extremities of said main cutter housing.
9. 10. A cutting assembly as claimed in claim 9, wherein said main inlet to said main cutter is provided with a cover which is closed and opened by the action of moving said cutter assembly from said operative position to said stowed position and back again. 12
10. 11. A cutting assembly substantially as hereinbefore described with reference to the accompanying drawings. DATED THIS NINETEENTH DAY OF DECEMBER 2000 BARTLEM PTY LTD BY PIZZEYS PATENT TRADE MARK ATTORNEYS