AU650540B2 - Mower housing - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1952 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) 650540 Name of Applicant: ELECTROLUX PTY LTD Actual Inventor(s): Graham John WHITE Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Invention Title: Mower Housing Details of Associated Provisional Application(s): No(s): PK6419/91 The following statement is a full description of this invention, including the best method of perfcnnming it known to me/us: *o* best method of perfcmiing it known to me/us: -1- MOWER HOUSING This -invention relates generally to grass mowers of the kind in which a skirted housing defines a chamber for 10 a blade assembly rotated by an engine mounted atop the housing. The invention is primarily concerned with certain improvements in the housing and in accessories associated with the housing.

The general configuration of mowers of the aforementioned kind is now well established. The housing is typically shaped to define an inverted grass cuttings S. ejection channel which sweeps upwardly from a low side of *S e the housing, around the front and the other side to a cuttings ejection opening at the rear of the housing.

20 The cuttings are swept up into a rear mounted catcher by a stream of air generated in the chamber and channel by the rotating blades, or in some models by a separate fan arrangement associated with the blade assembly. This typical housing configuration of most existing commercial mowers essentially entails entrainment of the grass cuttings in the air stream for tangential hurling of the cuttings through the rear opening into the catcher.

Attempts to improve the efficiency of cuttings collection and ejection have generally involved attempts to improve the initial generation of the air flow. For example, Australian patent specification 515003 proposes additional blading above the blade disc to generate an air vortex which passes downwardly about the blac;B tlisc and then reverts upwardly into an overlying peripheral cuttings collection chamber. Other approaches have involved improved cutting blade design so that a better air stream is created; the common cutting blade with the 920515,gnspc.008,cc=spc, I -2upwardly inclined rear segment was developed for this purpose.

It is an object of the present invention, in at least a first aspect, to provide a mower housing which enhances grass cuttings ejection from the housing.

The present inventor has realised that insufficient attention has been given in prior mower housing designs to the efficient motion of the air stream and entrained cuttings along the channel and out through the rear opening into the catcher. As a result, turbulence in the channel has adversely effected cuttings flow and in some instances has facilitated blockage. Quiescent corners have become accumulation points for cuttings, especially when wet, and the distribution of cuttings in the catcher has often been much less than optimum.

The invention accordingly provides, in a first aspect, a mower housing comprising: S- upper wall means, one or more skirt segments for defining an open- bottom chamber for a rotatable 20 blade assembly, and means for seating an engine to drive the blade assembly; 4000 said upper wall means including a segment which Sis of generally spiralling configuration and t.lereby defines a grass cuttings ejection channel that sweeps upwardly from a lower side portion of said upper wall means around the front of the housing to a higher side portion of said upper wall means, and thence away from the blade assembly to an ejection opening at the rear of the housing, said ejection opening extending across the housing behind the position of the engine when seated oii the housing; wherein said ejection channel includes a generally horizontal upper wall portion and an upright wall portion, which upright portion extends obliquely across the housing relative to said opening behind said engine, curves smoothly to terminate adjacent a respective side margin of said opening, is inclined with 920515,jnspe.OO8,emspe,2 -3respect to the normal to said lower side portion of the upper wall means and merges in respective smooth curves with said upper wall portion and with said low side portion of the upper wall means, whereby in use to enhance the air stream in said channel and thus the ejection of grass cuttings entrained in said air stream.

The inclination of the upright wall portion of the ejection channel with respect to said normal to the lower side portion of the upper wall means preferably 10 continuously changes as the wall portion extends o.

obliquely across the housing. The radius of curvature of said merger with the lower side portion of the upper wall means increases steadily from the central region of the .e.o housing towards the lateral periphery.

15 The housing preferably exhibits a general vertical central plane of symmetry, with respect to which said exit opening is generally perpendicular and with respect to which said upright wall portion extends obliquely across the housing at an angle generally between 50 and 85 degrees, most preferably between 60 and 80 degrees, to **said plane.

The upright wall portion is preferably inclined to the vertical with respect to the lower side portion of the upper wall means of the housing, preferably between 2 and 20 degrees, most preferably between 5 and 15 degrees.

In general, the wall portions defining the grass cuttings ejection channel are arranged so that discontinuities on the inner surface of the channel are avoided and corners are characterised by smooth and continuous curvature. The upper wall portion is preferably sloped radially outwardly with respect to the spiral, at an angle which progressively increases along the spiral, preferably reaching between 10 and 30 degrees in front of the grass cuttings ejection opening.

In many commercial mowers of the kind under consideration, the depending side skirts of the housing extend to generally upright terminal edges at the rear of 92051S,gjnspc.0G8,elcmsp,3 -4the housing separated by the ejection or exit opening for the grass cuttings. A brace usually bridges the lower rear corners of these skirts and a rear wheel axle is typically seated in complementary recesses at the bottom edges of the skirts. In accordance with a second aspect of the invention, the present inventor has appreciated that separate axle mountings can be avoided, and construction simplified and strength enhanced, by utilising the brace to also retain the main wheel axle.

An embodiment of the invention will be further described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a mower incorporating a housing in accordance with a preferred embodiment of the invention; Figures 2 and 3 are respective perspective views of the housing from above and below; Figure 4 is a plan view of the housing; Figure 5 is a cross-section on the line 5-5 in Figure 4;

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15 Figure 6 is a side elevational view of the housing; 0* Figure 7 is a cross section on the line 7-7 in Figure 6; Figures 8 and 9 are fragmentary views of the components of the rear axle assembly; Figure 10 is a rear view of a flap for closing the grass cuttings ejection 20 opening of the housing when a grass catcher is not in place; and e g.

0 0 oo ooo e• 940322p:\opcrkay,17347.sp,4 Figures 11 and 12 are cross sections on the lines 11-11 and 12-12 in Figure The illustrated mower 5 includes a housing 10 with front and rear ground wheels 6a, 6b, an engine assembly 0e

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0 C 0 0000 0 5055 5000 S SO SO S 00 SO O g S S 0 0 5050 0 C500 5g C S C S 0 05 1-> 940322,pAopcr\kaiy,17347.spe,5 -6- 7, a fold down handle assembly 8 and a detachable catcher 9. A blade assembly (not shown) is rotatable by engine 7 within housing The housing 10 is a single casting of a suitable material such as aluminium. The housing is of broadly conventional overall configuration, having upper wall means 12 and a partly peripheral skirt 14 which is part annular for an angular extent of about 250 degrees at the sides and front of the housing. Upper wall means 12 and skirt 14 define an open bottomed chamber 16 for a rotatable blade assembly (not shown) which would typically comprise a shaped disc and a pair of radially projecting pivotally attached grass cutting blades. A hose access hole is provided at 11 for washing the underside of the housing while the engine is running.

Skirt 14 defines the periphery of the housing at its respective sides but at the front an integral sktrted .extension 18 defines a sub chamber 20 (Figure 3) across which extends a cranked axle assembly 19 for the front 20 wheels 6a. This axle assembly 19 is retained in bearing slots 22 at each end of sub-chamber At the rear of housing 10, end segments 15a, 15b of skirt 14 curve until they are parallel and then end at generally upright but downwardly and outwardly inclined terminal edges 24a, 24b separated by and partly defining an ejection opening 26 for grass cuttings. A second cranked axle assembly 29 (Figures 8 and 9) for the rear wheels seats in respective recesses 30 in the bottom edges of skirt segments 15a, 15b. The lower edge of skirt 14 may be reinforced by a broad, slightly thickened rib 36 (shown only in Figures 6 and 7).

A circular opening 32 at the centre of upper wall means 3,2 is concentric with the part annular portion of skirt 14 and is bounded by a similarly concentric ring of pedestal mountings 34 for engine assembly 7. This engine assembly typically has a vertical power shaft which directly drives the underlying blade assembly. Three or 92051Sjpc,008,cIc.3Pe'6 -7four such pedestals 34 are provided at angularly spaced intervals on an annular raised land 35 with a peripheral sloped rim 33: this arrangement permits air to be drawn through opening 32 to enhance the cuttings ejection air stream and/or to facilitate a mulching process if provided.

Upper wall means 12 of housing 10 includes a segment 13 of generally spiralling configuration which defines an inverted grass cuttings ejection channel 40. This segment 13 has a broadly horizontal but radially outwardly sloped upper wall 42 bridging respective inner and outer side walls 44, 46. The outer side wall 46 is contiguous with skirt 14 along the side of the housing.

ChannelA--4 sweeps upwardly away from the blade assembly, from a low side portion 12a of upper wall means 12, around the front of the housing to a high side of the upper wall means and thence back to ejection opening 26.

The radially outward slope of upper wall 42 commences at a radius of central opening 32 nearly perpendicular to 20 the central vertical front-to-rear plane 10' of the housing 10 (indicated in Figure 4, normal to the page) and this radial slope increases gradually from this radius to reach about 20 degrees (Figure 5) in front of grass ejection opening 26.

Inner side wall 44 of channel 40 is upwardly and inwardly inclined with respect to channel 40 and curves closely adjacent the ring of pedestal mountings 34 until, as it re-approaches the aforementioned central plane this inner side wall 44 ceases this curvature and extends obliquely across the housing relative to grass ejection opening 26 and the central plane. This obliquely extending portion 44a of inner side wall 44 then curves smoothly around at 44b to terminate adjacent the respective side margin of opening 26. At this point, side wall 44b becomes vertically contiguous with skirt portion The obliquely extending portion 44a of channel side 920515,grmPe.W8.eectsm7 -8wall 44 is inclined at an increasing angle with respect to the normal to lower side portion 12a of upper housing wall means 12 and merges smoothly therewith with an increasing radius of curvature. It will be noted that the joins between the respective walls 42, 44; 42, 46 of channel 40 are characterised by smoothly and continuously curved wall segments as ie the transition from inner side wall 44 to the flat wall portion 12b about engine pedestal mountings 34.

It is found that, when grass catcher 9 is attached to the rear of housing 10 to embrace grass ejection opening 26, the collection of grass cuttings from under e Sthe mower and their ejection into the catcher is especially efficient, and that a very high rate of grass disposal can be achieved, even when the grass is wet. It is thought that this is due to the aerodynamically favourable shape of the channel 40 and in particular to the configuration of the rear broadened portion of the channel in front of opening 26. These features minimise turbulence, optimise flow of entrained grass cuttings, avoid boundaries at which flow separation is inclined to 5 e occur, and avoid pockets where grass, especially wet grass cuttings, might accumulate. It is furthermore found that highly compacted cuttings accumulate throughout the whole or almost the whole of the interior of the catcher: there is little of the tendency evident in many other housing/catcher arrangements for empty space to be found in a substantial portion of the catcher when ejection of grass cuttings has effectively ceased.

Turning now to the rear of the housing in the vicinity of the grass ejection opening, some other preferred novel features will be described. The lower corners of skirt segments 15a, 15b are interconnected and braced by a transversely extending outwardly flanged plate 50 with inwardly extending arms 52 at bach end by which the plate is fastened to the inner face of skirt segments 15a, 15b so as to extend across and close off 92O5SSgjnspC.OO8,IeeCCjSpc,8 -9recesses 30 for rear axle assembly 29. In this way, brace 50 serves a dual purpose by also retaining the axle assembly in the recesses.

Turning to Figures 8 and 9, axle assembly 29 includes a main axle 60 received in recesses Respective V-brackets 62 are welded at the ends of azIe and respective stub axles 64 for rear ground wheels 6b are fixed to one of the arms of each V. Attached to one of the V-brackets at one side of the housing is an 10 upstanding lever configuration including a leaf spring 66 and a hand grip rod 68. Leaf spring 66 has a central flat segment 69 and respective slightly inclined end segments 70, 71. Segment 70 is secured to the respective 62 ;bracke 644 and rod 68 extends through an aperture 71a in segment 71 parallel to segment 69 and is fastened to the latter. The rear face of segment 69 has a projection which selectively engages respective apertures in an indexing quadrant (not shown): this action is effected by pulling rod 68 against the leaf spring to disengage s 20 the spring from the indexing quadrant.

When catcher 9 is not attached to the rear of the housing 10, grass ejection opening 26 is closed by a flap illustrated in detail in Figures 10 to 12. Flap 80 is a single plate 81 of pressed galvanised steel with inturned lateral and bottom flanges 82 which fit round brace 50 and the side edges 24a, 24b defining opening 26.

At the top edge, plate 81 is rolled to form a pair of knuckles 84 by which the plate is rotatably supported from a hinge pin 85. Pin 85 extends between respective support pillars 4 to either side of opening 26, The centre region of flap 80 has an inwardly pressed oval shaped depression 88 (major axis horizontal) which projects as a dome through opening 26. This depression allows vA operator's hand to grip a strap 90 which is fixed across the depression to serve as a handle.

When the catcher is attached to ejection ofrning 26, flap 80 is raised and engages a complementary rib M$OSJnspc.OO8,eoccspc.9 configuration on the top of the catcher (Figure This engagement serves to retain the catcher at opening 26 in the conventional manner.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the iuclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

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Claims (14)

1. A mower housing comprising: upper wall means, one or more skirt segments for defining an open- bottom chamber for a rotatable blade assembly, and means for seating an engine to drive the blade assembly; said upper wall means including a segment which is of generally spiralling configuration and thereby defines a grass cuttings ejection channel that sweeps upwardly from a lower side portion of said upper wall means around the front of the housing to a higher side portion of said upper wall means, and thence away from the blade assembly to an ejection opening at the rear of the housing, said ejection opening extending across the housing behind the position of the engine when seated on the housing; S- wherein said ejection channel includes a generally horizontal upper wall portion and an upright wall portion, which upright wall portion extends obliquely across the housing relative to said opening behind said engine, curves smoothly to terminate adjacent a respective side margin ot said opening, is inclined with -the-respect to the normal to said lower side portion of the upper wall means and merges in respective smooth curves with said upper wall portion and with said low side portion of the upper wall means, whereby in use to enhance the air stream in said channel and thus the ejection of grass cuttings entrained in said air stream.

2. A mower housing according to claim 1, wherein said upright wall portion of the ejection channel has an inclination with respect to said normal to the lower side portion of the upper wall means of the housing of between 2 and 20 degrees.

3. A mower housing according to claim 2 wherein said inclination is between 5 and 15 degrees. 920515,gjnspc.008,eecspc 11 -12-

4. A mower housing according to claim 2 or 3 wherein said inclination continuously changes ds the upright wall portion extends obliquely across the housing.

5. A mower housing according to any one of claims 1 to 4, wherein said smooth curve merger with said lower side portion of the upper wall means has a radius of curvature which increases steadily from the central region of the housing towards a lateral periphery thereof on the same side of the housing as said lower side portion. 0*

6. A mower housing according to any one of claims 1 to wherein the housing exhibits a generally vertical Scentral front-to-rear plane, with respect to which said exit opening is generally perpendicular and with respect to which said upright wall portion extends obliquely across the housing at an angle between 50 and 85" to said plane.

7. A mower housing according to claimA-5-wherein said angle is between 60 and 80° to said plane.

8. A mower housing according to any preceding claim, wherein the wall portions defining the grass cuttings S 25 ejection channel are arranged so that discontinuities on the inner surface of the channel are avoided and corners are characterised by smooth and continuous curvature.

9. A mower housing according to any preceding claim, wherein said upper wall portion is sloped radially outwardly with respect to the spiral, at an angle which progressively increases along the spiral.

A mower housing according to claim 9, wherein said angle of slope reaches between 10 and 30 degrees in front of the grass cuttings ejection opening.

11. A mower housing according to any one of jlaims 1 to 920515,gjnspc.0G8,elecspe,12 -13- wherein said skirt: segment(s) extend to generally upright terminal edges at the rear of the housing separated by said ejection opening, said skirt segment(s) being provided with respective recesses formed in the bottom edges of said skirt segment(s) adjacent to the generally upright terminal edges for seating a rear wheel axle assembly, and with a bracing member which extends between and is fixed to said skirt segment(s) adjacent said upright terminal edges; and wherein said bracing member includes respective portions closing said recesses for retaining said rear wheel axle assembly.

12. A mower housing according to any one of claims 1 to 11 further including: ground wheels for the housing; and S means associated with the ground wheels for adjusting the height of the housing and thus of a blade assembly with respect to the ground; wherein said means associated with the ground wheels includes an upstanding lever and associated indexing means, the lever being movable between index positions by deflection of leaf spring means to which the lever is attached; and wherein the leaf spring means has respective portions inclined to each other, the lever projecting through an aperture in one of the portions, and extending parallel to and being secured to the other of the portions.

13. A mower including a mower housing according to any one of claims 1 to 12.

14. A mower housing or mower substantially as hereinbefore described with reference to the accompanying drawings. *o S Dated this 23rd day of March 1994 ELECTROLUX PTY LTD By Its Patent Attorneys Davies Collison Cave 940323p:Xopr\kay, 17347.spc, 13