WO2001015515A1 - Power lawnmower cutting system - Google Patents

Abstract

A power lawnmower (10) for cutting grass blades (G) comprising, a mower deck (12), a motor (M) mounted on the mower deck, a cutting system (45) supported within the mower deck, a plurality of cutter belt sheaves (55, 55') in the cutting system, a cutter belt (60) in the cutting system interconnecting the plurality of cutter belt sheaves, a drive assembly (65) powered by the motor for moving the cutter belt relative to the cutter belt sheaves, and a plurality of cutter assemblies (75) mounted on the cutter belt for effecting incremental cutting of the grass blades upon movement of the cutter belt and the lawnmower.

Description

POWER LAWNMOWER CUTTING SYSTEM

TECHNICAL FIELD The present invention relates generally to power lawnmowers. More particularly, the present invention relates to a power lawnmower cutting system having a plurality of blades mounted axially of a mower housing that are moved in a predetermined path to produce a series of very fine clippings attendant the mowing operation. More specifically, the present invention relates to a powered lawnmower having a plurality of blades with angled cutting edges that are mounted at spaced intervals along a continuous belt that is motor-driven in a path within the mower housing to progressively cut small lengths of grass blades as the mower advances.

BACKGROUND ART Lawnmowers have long been employed to facilitate the maintenance of turf surrounding homes and businesses where a relatively low grass height is desired to give the appearance of a well-kept lawn. Initially, most lawnmowers were of the reel type and were hand-pushed models in which both the mower and the reel rotation were the result of manual pushing action by the mower operator. Larger reel mowers were pulled in gangs by tractors or other power equipment for large industrial sites and particularly for golf courses and athletic fields of various types where short, precise grass cuts of high quality were demanded. Reel mowers have been preferred for precise grass cutting requirements because the blades create a scissor-like action, producing a clean, uniform cut. The number of blades mounted on a reel or spindle of a reel mower depends, in part, on the mowing height. Generally, where very short grass blade heights are dictated, as in the instance of golf course greens, tees, and, to a lesser extent, fairways, a greater number of blades are required to achieve a quality cut. The arrangement of the blades on a reel mower make the sharpening of the reel mower extremely difficult, thus requiring professional mower repair service and/or specialty equipment. Despite these disadvantages and attendant costs, reel mowers remain in extensive use in applications where clean, uniform cuts of a short blade height are dictated. The other primary type of mower is the rotary mower, which is characterized by a rotating element in the form of a blade or the like to cut grass blades. In general, these mowers use a horizontally-mounted cutting element that is rotated at a high rate of speed to sever grass blades at selected heights. As a result, rotary mowers require a motor to power the cutting system. The motor may or may not power the mower itself to thus create a self-propelled rather than a push-type rotary mower. Rotary mowers normally cannot cut at less than one inch or so grass blade height, and optimum mowing action normally takes place at even higher mowing heights. While optimum rotary mower performance requires a balanced and sharpened blade, such blade servicing can be accomplished relatively quickly and easily as compared with blade servicing of a reel- type mower.

Both reel mowers and conventional rotary mowers are designed to cut grass blades at essentially a single height, such that significant clippings are created in any instance where the mower cutting height is substantially less than the height of the grass. This potential problem can be solved by frequent cutting, such that the severed grass blade length is only a fraction of an inch. This approach is commonly used on golf course tees, greens, and fairways where virtually daily maintenance is feasible. Since such frequent mowing is not practical in most lawn maintenance programs, equipment has been developed to collect grass clippings for disposal. In this regard, catchers were developed for reel mowers in the area trailing the cutting area. For rotary mowers, a discharge chute has been developed that operates in conjunction with a bag attachment into which the grass clippings are directed by the air currents created by the rotating blade. In addition to the extra work and equipment required for the collection and disposal of grass cuttings, restrictions have been implemented in recent years on landfill disposal of grass clippings due to the volume of grass and leaf particles generated.

These considerations have, in recent years, led to the development of mulching mowers, which are designed to reduce the size of clippings and spread them as a fine mulch over the lawn to return nutrients to the soil. Such mulching mowers also eliminate the equipment and labor involved in collecting and disposing of grass clippings, not to mention the reduction in demands on landfill space. Although the configuration of reel mowers does not lend itself to mulching or multiple cutting to reduce the size of clippings, much has been done to develop mulching operations for rotary mowers. In the simplest sense, the discharge port of a conventional rotary mower may be blocked to prevent escape of cut grass such that it may be retained within the deck for multiple cuts before falling to the turf. Covering or eliminating the discharge port may also be coupled with a mulching blade to enhance the recutting of severed grass blades. In this respect, the mulching blades may have additional cutting elements or surfaces projecting from the rotating blade in various locations, which enhance the probabilities of multiple cuts to severed grass blades within the rotary mower housing before the clippings are discharged downwardly into the turf. More recently, rotary mowers designed exclusively for mulching have been developed, some of which include features such as specially designed mower decks and mulching blades that create air currents within the deck, which tend to suspend the clippings within the deck for longer time periods in order to effect finer cuts and create enhanced downward pressure, thereby forcing the mulched clippings downwardly into the grass in closer proximity to the turf so that it is less visible and subject to heightened decomposition. These rotary mulching mowers are, however, still subject to limitations as to the minimum length cut that can be made and require greater maintenance in regard to cleaning the interior of the deck to maintain air and grass clipping circulation, as well as the sharpening of additional blades.

Therefore, reel mowers remain the primary mower to achieve low, precise cuts, with the significant disadvantage of a lack of mulching capability, which thus requires labor-intensive, frequent cutting. Rotary mowers are currently capable of effecting significant mulching of longer grass blades; however, they lack the capability of cutting grass low to the ground and the precision cutting possible with a reel mower. Thus, there remains a need for a mower capable of effecting low, precise cuts while achieving multiple cuts of the grass blades, thereby discharging a finely powdered mulch. DISCLOSURE OF THE INVENTION Therefore, an object of the present invention is to provide a power lawnmower having a cutting system that is capable of cutting grass to low heights while contemporaneously effecting mulching of the grass blades into small pieces. Ano_ther object of the invention is to provide such a power lawnmower cutting system that accomplishes mulching action of grass blades by progressively effecting repeated small cuts on the grass blades as a function of mower travel. Still another object of the invention is to provide such a power lawnmower cutting system having a plurality of blades with cutting edges that are mounted at spaced intervals along a continuous belt that is motor driven in a path within the mower housing to repeatedly cut small lengths from upstanding grass blades as the mower advances.

Another object of the present invention is to provide a power lawnmower having a cutting system wherein a continuous belt having spaced cutters is mounted within a mower housing in such a manner as to define the desired cutting path for the mower. A further object of the invention is to provide such a power lawnmower cutting system in which the angled cutting blade extends below the drive system and sheaves that control the path of the continuous belt carrying the cutters of the cutter system to thus permit accurate cuts low to the ground. Yet another object of the present invention is to provide such a power lawnmower cutting system wherein the cutting blades are mounted relative to a spider or plate that is capable of being deflected with respect to the mower housing for an extent of flexibility in the event the cutting blades engage a foreign object.

Another object of the present invention is to provide a power lawnmower having a cutting assembly that is composed of a plurality of moving blades that are angularly oriented relative to the axial dimension of the mower housing and angularly oriented to standing grass blades under the mower such as to effect cuts at different locations along a grass blade, depending upon the portion of the cutting edge of the blade that engages the grass blade. A further object of the present invention is to provide such a power mower cutting system wherein a plurality of blades are affixed to a cutter belt by a mounting plate that extends through apertures in the belt and receives a locking pin on the side of the belt opposite the blade to thereby effect secure attachment of the blades to the cutting belt while permitting selective replacement of blades in the event of a damaged blade. A still further object of the invention is to provide such a power lawnmower cutting system wherein the cutting blades have two cutting edges geometrically oriented such that only one cutting edge is employed at a time, with the second cutting edge of the belt being accessible for cutting by inversion of the cutter belt. Yet a further object of the invention is to provide such a power lawnmower cutting system wherein the cutting blade is of a generally arrowhead configuration, with a cutting edge to either side of the point being employed to carry out the cutting function at any one time. Still another object of the present invention is to provide a power lawnmower having a cutting system wherein the cutting characteristics as to the length of grass blade particles being cut may be controlled by varying the speed of the mower, varying the velocity of the cutting belt carrying the blades and/or varying the distance between blades positioned along the cutter belt. Another object of the invention is to provide such a power lawnmower cutting system that may be operable in conjunction with a manually movable mower, a self-propelled mower powered by the motor driving the cutter belt, a riding mower, or a mower that may be towed by a tractor or other vehicle.

Yet a further object of the present invention is to provide such a power lawnmower cutting system that is relatively non-complex; that is of rugged construction to withstand the operating environment; that permits ready replacement of cutting blades or an entire cutting belt assembly, including the blades; that is otherwise relatively simple to operate, maintain and service; and that is safe to operate in that it is not prone to throwing foreign objects, which may be engaged by the blades.

In general, the present invention contemplates a power lawnmower for cutting grass blades, including a mower deck, a motor mounted on the mower deck, a cutting system supported within the mower deck, a plurality of cutter belt sheaves in the cutting system, a cutter belt in the cutting system interconnecting the plurality of cutter belt sheaves, a drive assembly powered by the motor for moving the cutter belt relative to the cutter belt sheaves, and a plurality of cutter assemblies mounted on the cutter belt for effecting incremental cutting of the grass blades upon movement of the cutter belt and the lawnmower.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a top plan view of a power lawnmower having an exemplary cutting system according to the concepts of the present invention with portions broken away to show details of the cutting system.

Fig.2 is a side-elevational view of the power lawnmower of Fig. 1 with portions broken away to show the interrelation between the drive assembly and the cutting system. Fig.3 is an enlarged fragmentary sectional view, taken substantially along the line 3-3 of Fig. 1 , showing details of a cutter assembly of the cutting system.

Fig.4 is an enlarged top plan view, partially in section, of a fragmentary portion of the cutting system showing details of the attachment of cutter assemblies to the cutter belt and its relation to one of a plurality of positioning sheaves.

Fig. 5 is an exploded perspective view showing further details of the cutter assembly components effecting attachment to the cutter belt.

PREFERRED EMBODIMENT FOR CARRYING OUT THE INVENTION

A power lawnmower according to the concepts of the present invention is generally indicated by the numeral 10 in Figs. 1 and 2 of the drawings. As shown for exemplary purposes, the power lawnmower 10 has a mower deck, generally indicated by the numeral 12, as a major structural component thereof. As shown, the mower deck 12 includes a generally planar or outwardly convex deck top 13 that is of a generally semicircular configuration, as seen in Fig. 1 , and that could be otherwise configured to accommodate a seat (not shown) or other components, depending upon the particular mower configuration. It is to be appreciated that while a self-propelled mower is depicted for exemplary purposes, the concepts of the instant invention are also applicable to a push mower with a powered cutting system and riding and towed mower variations.

Extending from the outer periphery of the deck top 13 is a sidewall 14 that is generally perpendicular to, or extends axially from, the deck top 13 a sufficient distance to form a generally enclosed partial cylindrical configuration. The sidewall 14 of mower deck 12 may have a slightly outwardly flared skirt 15 that terminates at its lower axial extremity in an upturned flange 16, as best seen in Fig.3. When the mower 10 is moved in the direction of the arrow, the skirt 15 and the flange 16 facilitate deflection of grass blades G growing out of turf T, as depicted in Fig. 3. The grass blades G return to an upright position upon entering the cutting area of power lawnmower 10 within the confines of the mower deck 12 due to its natural resilience.

The mower deck 12 is provided with a plurality of forward support wheel assemblies 20 that maintain the front of mower deck 12 positioned at a substantially uniform distance above the ground or turf T. As seen in Figs. 1 and 2, the support wheel assemblies 20 have mounting arms 21 that are attached to the deck top 13 as by fasteners 22. The mounting arms 21 carry wheels 23 that extend downwardly a distance sufficient to space the mower deck 12 and, particularly the flange 16, a desired distance above the ground or turf T. If desired to provide for varying the height of mower deck 12 relative to the turf T, the support wheel assemblies 20 may be provided with manual or hydraulic adjusters (not shown) to raise and lower the wheels 23 relative to the mounting arms 21 or the deck top 13 according to apparatus well known to persons skilled in the art. The wheels 23 may also be of a multi-directional or zero degree turn radius design to permit movement of the mower 10 in any direction from a given position.

The lawnmower 10 is powered and supported rearwardly of the mower deck 12 by a drive wheel assembly, generally indicated by the numeral 25 in Figs. 1 and 2. The drive wheel assembly 25 is supported relative to the mower deck 12 by rear mounting arms 26, which may be affixed to the deck top 13 as by fasteners 27. The rear mounting arms 26 support an axle 28 that carries a plurality of wheels 29, which support the rear of the mower deck 12. A suitable drive transmission and braking gearbox 30 is operatively mounted on and controls the axle 28. The transmission and braking gearbox 30 may be designed to provide a minimum turn radius to further enhance mobility of the mower 10 in a known manner.

The drive transmission and braking gearbox 30 is powered by a mower drive belt

35, which couples a driven pulley 36 on an input shaft 37 of the drive transmission and braking gearbox 30 with mower drive pulley 38. The mower drive pulley 38 is on the output shaft 39 of mower motor M, which is shown schematically in Figs. 1 and 2. The exemplary lawnmower 10 is thus self-propelled and capable of a high degree of mobility, if desired.

The lawnmower 10 is provided with a cutting system, generally indicated by the numeral 45 in Figs. 1 and 2 of the drawings. The cutting system 45 consists of a spiderlike frame 46 that has a central body portion 47 with a plurality of extending fingers 48. The fingers 48 preferably extend from the body 47 of frame 46 over approximately the 180° circumferential portion of the mower deck 12. As can be seen, the fingers 48 preferably extend toward, but are spaced a distance from, sidewall 14 of mower deck 12, such as to roughly define the cutting width of the lawnmower 10. In addition to the fingers 48, frame 46 of cutting system 45 may have a rear projection 49 extending from body portion 47. As best seen in reference to Figs. 1 and 3, the frame 46 of cutting system 45 is resiliently suspended on a plurality of bolts 50 which, as shown, extend through the fingers 48 of frame 46 and through the deck top 13 of the mower deck 12. A suitable fastener, such as a locknut 51, is positioned above the deck top 13 and threaded onto the bolts 50 to selectively retain the frame 46 of cutting system 45 in the desired position within the mower deck 12. A compression spring 52 may be located on each of the bolts 50 to maintain the fingers 48 of frame 46 and the deck top 13 in the desired spaced relation and to permit the frame 46 of cutting system 45 to deflect a distance upwardly in the event the cutting system 45 engages a foreign object or is otherwise subject to an upward force during operation of the lawnmower 10.

A plurality of idler sheaves 55 are mounted on the fingers 48 of the frame 46. As seen in Figs. 1 -3, the idler sheaves 55 are preferably mounted proximate to the extremity of the fingers 48 in such a manner that the outer extremities of the sheaves 55 define a semi-circular path that is proximate to but spaced a distance from the skirt 15 of the mower deck 12 (see Fig. 1). The idler sheaves 55 are affixed to the fingers 48 of frame 46 as by a bolt 56, which provides an axle therefor and may extend through a lower cylindrical sleeve 57, finger 48, and upper cylindrical sleeve 58, where it is retained by a nut 59. The distance that idler sheaves 55 are positioned below fingers 48 may be varied by employing lower cylindrical sleeves 57 of differing axial extent. The position of sheaves 55 axially of the mower deck 12 may also be varied by the length of the bolts 50 and the axial extent of the compression springs 52. One or more idler sheaves 55' may be mounted on the rear projection 49 of the frame 46. As shown in Fig. 1 , there are three such idler sheaves 55'. One or more of idler sheaves 55, 55' may be adjustably positionable to selectively control the tension in the cutter belt 60 in a manner well known to persons skilled in the art.

The idler sheaves 55 and 55' support a cutter belt 60, as seen in Figs. 1-3. As shown, the cutter belt 60 is a V belt that is maintained in a planar, horizontal position paralleling deck top 13 by virtue of the positioning of the idler sheaves 55 and 55'. The cutter belt 60 and idler sheaves 55 and 55' are driven by a cutter system drive assembly, generally indicated by the numeral 65 in Figs. 1 and 2. The cutter system drive assembly 65 contemplates one or more drive sheaves 66 that are aligned with the idler sheaves 55 and 55', which power the cutter belt 60 to effect its tangential motion relative to idler sheaves 55 and 55'. As shown, the drive sheaves 66 are disposed at 180° relative to the center of central body portion 47 of frame 46 on the fingers 48 representing the fingers 48 with the lateral-most projections. The drive sheaves 66 are mounted on fingers 48 similar to the idler sheaves 55 and 55', except that sheaves 66 are mounted on sheave drive shafts 67, which extend through deck top 13 of the mower deck 12. Positioned on the sheave drive shafts 67 above deck top 13 are cutter drive pulleys 68, which are engaged by a cutter drive belt 70. The cutter drive belt 70 is powered by the aforesaid mower motor M, which may also make lawnmower 10 self-propelled in the manner described hereinabove. In particular, the output shaft 39 of mower motor M carries a cutter drive belt pulley 69 that powers the cutter drive belt 70. The position of the cutter drive belt 70 may be controlled relative to the cutter drive pulleys 68 by one or more idler pulleys 72, which may also be adjustably positionable to control the tension in cutter drive belt 70 according to desired operating conditions. Thus, it is apparent that the mower motor M drives or powers the mower deck 12 across the turf T, as well as driving the cutter belt 60 through the cutter system drive assembly 65.

The cutter belt 60 carries a plurality of cutter assemblies, generally indicated by the numeral 75, as seen in each of the drawing Figs. 1-5. As can be appreciated from Fig. 1 of the drawings, the cutter assemblies 75 are preferably substantially equally spaced along the periphery of cutter belt 60. A spacing of approximately four inches has been found satisfactory to achieve the fine mulch cut characteristics desired for the mower 10 with a normal mower speed and belt rotation. It is, of course, to be appreciated that the speed of cutter belt 60 may be altered by variations in the relative diameter of the cutter drive belt pulley 69 and the cutter drive pulleys 68, as well as the speed of the mower motor M.

The cutter assemblies 75 each consist of a blade 76 mounted on the radially outward surface of cutter belt 60. As shown, the blade 76 of cutter assemblies 75 includes a belt-engaging surface 77 that is adapted to conform to the radially outer surface of cutter belt 60. The blade 76 has at least one wing 78 that has a cutting edge 79 that is disposed at an angle of approximately 45° relative to a direction axially of the mower deck 12, such that it tapers radially inwardly while progressing in a direction axially outwardly of the mower deck 12. It is also to be appreciated that varying the angle between the direction axially of mower deck 12 and cutting edge 79 will effect the incremental size of the cut grass G, with the speed of the mower 10 and the speed of the cutter belt 60 remaining constant. In this respect, increasing the angle would produce smaller grass blade increments, whereas decreasing the angle would produce larger grass blade increments. An exemplary depiction of the multiple blade increments cut by mower 10 is depicted in Fig.3, where the mower sidewall 14 has moved to the chain line position 14' when a succeeding blade 76 on cutter belt 60 has moved to the chain line position 76', with the grass blade increments cut by succeeding blades 76 indicated as G'.

While the blades 76 of cutter assemblies 75 might have only the lower wing 78 with the cutting edge 79, a preferred blade according to the present invention is shown in the drawings as having an arrowhead configuration. The depicted arrowhead configuration has the advantage of a more balanced cutter belt 60 and an extended life of the cutter assemblies 75. In particular, the arrowhead configuration has an upper wing 80 with a cutting edge 81 that balances the cutter assemblies between the lower wing 78 and the upper wing 80. Since the cutting is effected primarily by the lower wing 78 and its cutting edge 79, as depicted in Fig. 3, the blade 76 may be inverted on cutter belt 60 in the event the lower wing 78 is damaged or cutting edge 79 is somehow dulled or damaged. Alternatively, the arrowhead blade configuration permits the entire cutter belt 60 to be inverted to effectively double the life of a blade 76.

In either instance, the cutter assemblies 75 have a pair of mounting plates 85 and 86 that are affixed to either side of the blade 76 as by welds 87 and 88, respectively. The mounting plates 85 and 86 each have a projecting tab 89 and 90, respectively, which extends through apertures 61 (see Fig.5) in the cutter belt 60. The tabs 89, 90 have bores 91 that are located on the radially inner side of cutter belt 60 when the blade 76 is in position on cutter belt 60. The bores 91, 91 each receive expansible pins that preclude movement of the tabs 89, 90 without removal of the pins 92. The pins 92 may be of a rolled metal, such that the axial extremities may be expanded once the pins are in position to assure that the pins 92 cannot escape from the bores 91 due to the motion of the cutter belt 60. Alternatively, the pins 92 may be cotter pins. A cutter belt 60 may be employed that has grooves or slots 62 on the radially inner surface thereof, with the apertures 61 extending into grooves or slots 62, which seat the pins 92 such that motion of the cutter assemblies 75 relative to cutter belt 60 is further restrained, particularly when a blade 76 encounters a foreign object. While a pair of mounting plates 85, 86 are shown and described herein, it will be appreciated that a single mounting plate slotted to receive blade 76 may be employed with either one or two tabs extending through the cutter belt 60 and secured by pins 92, as hereinabove described.

Thus, it should be evident that the power lawnmower cutting system disclosed herein carries out one or more of the objects of the present invention set forth above and otherwise constitutes an advantageous contribution to the art. As will be apparent to persons skilled in the art, modifications can be made to the preferred embodiments disclosed herein without departing from the spirit of the invention, the scope of the invention herein being limited solely by the scope of the attached claims.

Claims

CLAIMS 1. A power lawnmower for cutting grass blades comprising, a mower deck, a motor mounted on said mower deck, a cutting system supported within said mower deck, a plurality of cutter belt sheaves in said cutting system, a cutter belt in said cutting system interconnecting said plurality of cutter belt sheaves, a drive assembly powered by said motor for moving said cutter belt relative to said cutter belt sheaves, and a plurality of cutter assemblies mounted on said cutter belt for effecting incremental cutting of the grass blades upon movement of said cutter belt and the lawnmower.

2. A power lawnmower according to claim 1 , wherein said cutter assemblies include a blade oriented substantially axially of said mower deck.

3. A power lawnmower according to claim 2, wherein said blade has an arrowhead configuration.

4. A power lawnmower according to claim 2, wherein said blade has a cutting edge that tapers radially inwardly in a direction axially outwardly of said mower deck.

5. A power lawnmower according to claim 4, wherein said cutting edge is disposed at an angle of approximately 45 degrees relative to a direction axially of said mower deck.

6. A power lawnmower according to claim 4, wherein said blade has a second cutting edge that tapers radially inwardly in a direction axially inwardly of said mower deck.

7. A power lawnmower according to claim 1 , wherein said cutter belt sheaves are mounted in a substantially semi-circular configuration.

8. A power lawnmower according to claim 7, wherein said cutter belt sheaves are suspended from a spider having a central portion with extending arms carrying the sheaves and affixed to said mower deck.

9. A power lawnmower according to claim 8, wherein said spider has bolts affixing said arms of said spider to said mower deck with compression springs interposed therebetween to permit an extent of axial deflection of said arms relative to said mower deck.

10. A power lawnmower according to claim 8, wherein said sheaves are carried on bolts extending through said arms with annular sheaves of a selected length being interposed between said arms and said sheaves for locating said sheaves and said cutter assemblies relative to said mower deck to effect a preselected cutting height of the grass blades.

11. A power lawnmower according to claim 1 , wherein said cutter belt is continuous and said cutter assemblies are mechanically secured to said cutter belt at substantially uniform intervals.

12. A cutting system for a lawnmower having a deck positionable in operative relation to grass blades to be cut comprising, a motor mounted on the deck, a plurality of sheaves mounted within the deck, a cutter belt engaging and positioned by said sheaves, a cutter drive assembly powered by said motor and driving said cutter belt relative to said sheaves, and a plurality of cutters mounted on said cutter belt for cutting the grass blades upon movement of said cutter belt and the lawnmower.

13. A cutting system according to claim 12, wherein said cutters are affixed to said cutter belt at substantially uniform intervals therealong.

14. A cutting system according to claim 12, wherein said cutter belt is a V-shaped belt.

15. A cutting system according to claim 13, wherein said cutters have a mounting plate with a blade on one side of said cutter belt and at least one tab extending to and affixed at the other side of said cutter belt.

16. A cutting system according to claim 15, wherein said tab extends through an aperture in said cutter belt and has a bore for receiving a retaining pin.

17. A cutting system for a lawnmower having a deck positionable in operative relation to grass blades to be cut comprising, a motor mounted on the deck, a plurality of sheaves mounted within the deck, a cutter belt engaging and positioned by said sheaves, a cutter drive assembly powered by said motor and driving said cutter belt relative to said sheaves, a plurality of cutting assemblies having cutters, and means for mounting said cutting assemblies at intervals along said cutter belt for cutting the grass blades upon movement of said cutter belt and the lawnmower.

18. A cutting system for a lawnmower according to claim 17, wherein said cutters are substantially planar and oriented axially of the deck.

19. A cutting system for a lawnmower according to claim 17, wherein said cutter assemblies have mounting plates with tabs extending through said cutter belt and retained by pins.

20. A cutting system for a lawnmower according to claim 19, wherein said cutter belt has transverse grooves for seating said pins.

21. A cutting system for a lawnmower, including an endless belt mounted to the lawnmower and maintained in a substantially horizontal plane and a cutter mounted to said belt, said cutter having a cutting edge that tapers inwardly while progressing normally to the horizontal plane of said belt.

22. A cutting system for a lawnmower according to claim 21 , wherein said cutter has an arrowhead configuration.