Reel mower with cutting units suspended by double A arm suspensions

A reel mower has a plurality of reel cutting units. Each reel cutting unit is connected to a frame of the reel mower by its own double A arm suspension that lowers a reel cutting unit into a cutting position in a tail down orientation and that levels the reel cutting unit out as it lifts the reel cutting unit into a transport position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of previously filed provisional application Ser. No. 61/133,285, filed Jun. 27, 2008.

TECHNICAL FIELD

This invention relates to a reel mower having one or more reel cutting units that each comprises a rotatable cutting reel that sweeps grass against a sharpened bedknife for shearing the grass against the bedknife.

BACKGROUND OF THE INVENTION

Reel mowers having a self propelled mower frame and mounting a plurality of reel cutting units are well known for precision mowing of grass. In such mowers, the reel cutting units typically are self-supporting and roll over the ground during cutting using one or more ground engaging rollers carried on the reel cutting unit itself. A suspension mounts each such reel cutting unit to the mower frame so that the reel cutting units are propelled by motion of the mower frame. The suspension is designed to allow the reel cutting unit various degrees of freedom of motion relative to the suspension by means of which the reel cutting units can individually adapt themselves to the contours of the ground to provide a higher quality of cut.

In recent times, there has been an increasing focus on further improving the quality of cut. The goal is to cut the grass at low heights of cut with few or no discernible flaws of any type. Thus, to the extent prior art suspensions permitted reel cutting units to cut grass with any unevenness in the cut that could be seen by the visible eye, or the extent prior art grass collectors attached to such reel cutting units permitted grass clippings to fall out or be left on the cut grass path even in minute quantities, the customers of such equipment are becoming increasingly less tolerant of such imperfections. It would be an advance in the art to provide suspensions that allow the reel cutting units to provide a more uniform and even cut and to provide grass collection that minimizes or eliminates any stray clippings from being left on the cut grass path. This invention is directed in part to such improvements.

Another important aspect of such mowers is how easily they can be serviced. In this regard, certain of the reel cutting units, such as the center rear cutting unit in a triplex configuration, are generally located underneath the mower frame. Access to such a cutting unit is thus difficult. Moreover, the cutting units themselves can be difficult to remove from the rest of the mower, requiring that they be bolted or unbolted to the mower suspension. The same is true for the drive motors that might be attached to the reel cutting units to power the rotatable reels thereof. Thus, it would be a further advance in the art, and one to which this invention is also directed, to provide cutting units that can be quickly and easily detached from their suspensions, that have drive motors that can be quickly and easily detached from the cutting units, and to have a way to more easily access any obstructed cutting units, such as the center rear cutting unit mentioned above.

SUMMARY OF THE INVENTION

One aspect of this invention relates to a reel mower having a mower frame supported for rolling over the ground. A power source is carried on the mower frame. An operator's station is also carried on the mower frame for supporting an operator thereon. A plurality of reel cutting units is further carried on the mower frame. A suspension operatively connects each reel cutting unit to the mower frame. Each suspension for each reel cutting unit includes a pair of pivotal suspension arms comprising an upper suspension arm and an underlying lower suspension arm.

Another aspect of this invention relates to a reel mower of the general type noted above. In this aspect, the suspension instead of that set forth above includes instead a substantially vertical pivot axis about which the reel cutting unit pivots to permit the reel cutting unit to yaw relative to the mower frame during turns of the mower frame when the reel cutting unit is in engagement with the ground in a cutting position. The vertical pivot axis is inclined or canted relative to vertical at a negative angle that points rearwardly relative to the reel cutting unit and relative to vertical as one proceeds downwardly along the angle of inclination.

Yet another aspect of this invention relates to a reel mower of the general type noted above. In this aspect, the suspension instead of that set forth above includes a plurality of transversely spaced, pivotal clamps that tightly clamp the reel cutting unit against a remaining portion of the suspension when the clamps are tightened to thereby releasably attach the reel cutting unit to the remaining portion of the suspension. A tab or finger is provided that can be moved back and forth manually by an operator in opposite directions to loosen and tighten each pivotal clamp without using a tool to thereby allow the reel cutting unit to be quickly detached from and attached to the remaining portion of the suspension, respectively.

An additional aspect of this invention relates to a reel mower of the general type noted above. In this aspect, the suspension instead of that set forth above includes a cutting unit carrier frame that pivotally connects to the cutting unit frame such that the reel cutting unit pitches fore and aft relative to the cutting unit carrier frame about a substantially horizontal pitch axis. A grass basket is provided having an open mouth through which the grass clippings are thrown into the grass basket for collection therein. The grass basket is pivotal on the cutting unit carrier frame such that gravity acting on the grass basket causes the grass basket to pivot towards the reel of the reel cutting unit during operation of the reel cutting unit. At least a portion of the grass basket abuts against a portion of the cutting unit carrier frame to maintain a lower lip of the open mouth of the grass basket at a predetermined clearance to the cutting reel with such clearance remaining substantially constant even as the reel cutting unit pitches back and forth about the pitch axis

One more aspect of this invention relates to a reel mower of the general type noted above. In this aspect, the suspension instead of that set forth above simply operatively connects the reel cutting unit to the mower frame. A grass basket is provided for collecting grass clippings cut by the reel cutting unit. The grass basket has a weight that increases with the amount of grass clippings held in the grass basket. The grass basket is operatively connected to a cutting unit frame of the reel cutting unit in a manner that transfers the weight of the grass basket to the reel cutting unit such that the weight of the reel cutting unit is borne by the cutting unit as the cutting unit rolls on the ground. A counterbalance system offsets increasing weight of the grass basket. The counterbalance system comprises at least one biasing member for applying a biasing force to the suspension in a direction that tends to counterbalance the weight of the reel cutting unit including the weight of the grass basket, a sensor for detecting increasing weight of the grass basket due to the grass basket becoming more loaded with grass clippings, and an actuator responsive to the sensor for acting on the biasing member to increase the biasing force to counteract increasing weight of the grass basket.

DETAILED DESCRIPTION

The Overall Mower

FIGS. 1 and 2illustrate one embodiment of a mower2according to this invention. Mower2comprises a frame4supported for rolling over the ground by a pair of front wheels6fand a single rear wheel6rarranged in a triangular configuration. The rear of mower frame4includes an engine compartment10that is normally covered and enclosed by an engine shroud or hood8. An internal combustion engine or other suitable power source, such as a battery pack, hybrid electric drive system, fuel cell, etc., is mounted in engine compartment10. Various other components can be housed on or adjacent the engine within engine compartment10, such as drive train components, controls, etc.

A hydraulic system (not shown) is carried on mower frame4and is powered by the engine for providing pressurized hydraulic fluid flow for powering various components of mower2. For example, the hydraulic system includes an engine driven hydraulic pump that powers one or more hydraulic motors that drive one or more of wheels6to cause mower2to be self propelled. Typically, front wheels6fare driven by the hydraulic system while rear wheel6rmay or not be driven depending upon whether mower2is in a two wheel drive (2WD) or three wheel drive (3WD) configuration. The single rear wheel6rcould be replaced by a pair of rear wheels6rand mower2could have a four wheel drive (4WD) configuration if both rear wheels6rare also driven. The numbers of wheels6carried on mower frame4, their placement relative to one another on mower frame4, and whether all or only some of wheels6are driven can obviously vary.

An operator's station is carried on mower frame4. The operator's station includes a seat12for carrying a seated operator. A control console14carrying various operational controls is mounted adjacent one side of seat12. Control console14and seat12are together carried on an operator's station subframe16.

The front of mower frame4in advance of seat12has a U-shaped frame member18that opens towards the front to create an open space20in front of seat12. During normal operation of mower2, open space20is closed to access from the front by an upwardly inclined footrest22that extends in front of seat12. If one were to try and walk into space20from the front, one would hit footrest22and be prevented from reaching open space20. The operator can rest his or her feet on footrest22while the operator is operating mower2. If desired, various accelerator and foot pedal controls (not shown) can be located on a portion of footrest22for use by the operator in controlling the traction speed of mower2.

A steering system comprises an L-shaped steering column24that mounts a steering wheel26. Steering column24is cantilevered from one side of mower frame4such that the long leg of the L-shape extends vertically along one side of mower frame4and the short leg of the L-shape is horizontal and extends inwardly in front of operator's seat12. Steering wheel26is located on the short, horizontal leg of steering column24immediately in advance of operator's seat12to allow an operator who is seated on seat12to steer mower2. Rotation of steering wheel26by the operator pivots the single rear wheel6rabout a vertical axis for steering mower2. Alternatively, steering wheel26can be used to pivot or steer other of the wheels6. However, in the three wheel configuration depicted inFIGS. 1 and 2, it is preferred that the single rear wheel6rbe the steerable wheel.

Various reel cutting units28are carried on mower frame4in a triplex gang configuration. Cutting units28comprise a pair of front cutting units28fcarried in advance of front wheels6fwith front cutting units28fbeing separated transversely from one another by a gap. A center rear cutting unit28ris carried behind front cutting units28fand is located to cover the gap between front cutting units28fso that mower2cuts a single unbroken swath of grass in each pass of mower2. Center rear cutting unit28ris located on mower frame4generally between front wheels6fof mower frame4and in advance of rear wheel6r.

Other gang configurations of cutting units28could be used. In addition, additional rear cutting units28rcould be added to mower frame4on either side of center rear cutting unit28rto expand the triplex configuration to a fiveplex configuration, and additional front cutting units28fcould be added outboard of each of front cutting units28fto expand a fiveplex to a sevenplex.

Access to the Engine Compartment and to the Center Rear Cutting Unit

Referring now toFIG. 2, engine hood8can be pivoted upwardly and rearwardly on mower frame4about a transverse pivot axis to substantially expose engine compartment10and more particularly to expose the rear of engine compartment10. With engine hood8pivoted to its open position as shown inFIG. 2, any components within engine compartment10that would have been covered by hood8are exposed. These components can be reached and easily serviced by someone who simply stands to one side of the rear of mower frame4. Thus, simply pivoting hood8upwardly and rearwardly leads to easier service or maintenance for much of engine compartment10.

However, the front of engine compartment10is covered, not by engine hood8, but by operator's seat10and control console14. Thus, subframe16is pivotally carried on mower frame4for rotation about a longitudinal pivot axis such that subframe16, and thus operator's seat12and control console14, can be pivoted 90° to one side of mower frame4as also shown inFIG. 2. The steering system is not, however, carried on subframe16and so does not pivot with subframe16. Thus, when operator's seat12and control console14are pivoted to the side as shown inFIG. 2, steering column24and steering wheel26remain in their usual location on mower frame4.

The purpose of pivoting subframe16to the side of mower frame4as shown inFIG. 2is to expose or open up the front of engine compartment10for service or maintenance. Obviously, engine hood8can be pivoted upwardly and rearwardly, or subframe16can be pivoted to the side independently and separately from one another, depending upon whether one wishes to expose the rear of engine compartment10or the front of engine compartment10. For example, if the components that need servicing are located in the rear of engine compartment10and are only covered by hood8, then only hood8need be pivoted and subframe16can stay in its normal, non-pivoted orientation. However, the entire engine compartment from front to rear can be exposed if so desired by pivoting both subframe16and engine hood8.

Footrest22located in front of operators' seat12is preferably provided in two portions. The first portion comprises a fixed footrest22fthat is fixed to mower frame4on the right of mower frame4. The second portion is a pivotal footrest22pthat pivots at the left side of mower frame4about a longitudinal pivot axis. Fixed footrest22fmounts whatever foot pedal controls are used on mower2. Fixed footrest22fis very narrow compared to pivotal footrest22p. For example, fixed footrest22fextends laterally only 10 to 20% or so of the entire width of footrest22while pivotal footrest22pfills in the remaining 80% to 90% or so the width of footrest22.

As shown inFIG. 1, pivotal footrest22phas a usual, operational position in which it is rotated down and is flush with fixed footrest22fas shown inFIG. 1. In this position, pivotal footrest22pblocks access to open space20formed by U-shaped frame member18. Alternatively, as shown inFIG. 2, pivotal footrest22pcan be rotated 90° to the side to an access or service position in which pivotal footrest22pextends vertically and does not block open space20.

When pivotal footrest22pis rotated into its access or service position as shown inFIG. 2, the path is clear for an operator or a mechanic to walk back into open space20defined by frame member18through the opening or gap that exists between front cutting units28fas indicated by the arrow A inFIG. 2. Center rear cutting unit28ris located on mower frame4at least partially within open space20though the back of center rear cutting unit28rmight be tucked in back behind the cross bar of frame member18. Thus, merely by pivoting pivotal footrest22pto the side as shown inFIG. 2, one can easily reach center rear cutting unit28rto service, adjust or even remove center rear cutting unit28r. This task is further eased since each cutting unit28disclosed herein, including center rear cutting unit28r, can be raised up off the ground into a service position where the cutting unit is tilted up by an angle of approximately 50° to 70° or so, as shown by the tipped up orientation of cutting units28inFIG. 1. When center rear cutting unit28ris disposed in this tipped up service position, even the undersides of the cutting unit are exposed to one who has reached open space20by flipping up pivotal footrest22pand by walking back through the gap between front cutting units28f. Alternatively, front cutting units28fcan be removed from their suspensions30(as described hereafter in the section entitled Easily Removable Cutting Unit) to more completely open up the path to center rear cutting unit28r.

In many prior art mowers, center rear cutting unit28ris located entirely or almost entirely under mower frame4. While center rear cutting unit28rcan typically be lifted and lowered off the ground, it is difficult to service, adjust or maintain such a cutting unit because of the interference with the overlying mower frame4. However, because of the placement in mower2of center rear cutting unit28rat least partially within an open space20at the front of mower frame4, and because the operator can selectively access space20simply by flipping up a pivotal footrest22p, the difficulty of servicing, adjusting or maintaining center rear cutting unit28rhas been substantially decreased. This is an advantage to anyone who might work on such mowers.

In other prior art mowers, attempts have been made to increase the ease of servicing a center rear cutting unit by carrying the cutting unit on a pivotal arm to allow the center rear cutting unit to be selectively swung out from under the mower frame to a service position in which the center rear cutting unit is beside the mower frame and thus is exposed. While effective, this solution involves the use of additional structure, such as the pivotal arm and various latches and the like for latching the arm and the center rear cutting unit in its usual operational position. It also complicates the task of lifting and lowering the center rear cutting unit off the ground.

These disadvantages are avoided in the approach disclosed herein. All that is required is to appropriately locate center rear cutting unit28rat least partially within open space20at the front of mower2and to allow an operator to access this space. Access is easily and inexpensively provided simply by pivoting a portion of footrest22, a part that would normally be present on mower2. Thus, no additional parts are required except for the pivot pin(s) that mount pivotal footrest22pto mower frame4.

In addition, the increased access provided by pivotal footrest22pto open space20at the front of mower frame4is useful in allowing access to the front of engine compartment10from the front of mower2rather than simply from the side. Thus, with pivotal footrest22ppivoted to the side as shown inFIG. 2, and with subframe16also pivoted to the side as shown inFIG. 2, a person standing in open space20can easily reach into and service the front of engine compartment10from the front. This allows such a person to more easily service any components that are located at the right front of engine compartment10. Such components would otherwise be the furthest away from someone standing adjacent the left side of mower frame4which is where someone would otherwise have to stand to service the front of engine compartment10when subframe16is pivoted to the right side of mower2.

Various modifications of the fixed and pivotal footrests are possible. For example, it is preferred that fixed footrest22fcarry the foot pedal controls for mower2since any linkages extending to such foot pedal controls will remain in place and be undisturbed by pivoting the separate pivotal footrest22p. However, if so desired, footrest22could be split into two pivotal portions22pof more equal size with one portion pivoting to the right side of mower frame4and the other portion pivoting to the left side of mower frame4, i.e. opening and closing like barn doors. The portion pivoting to the right side of mower2could further be integrated with subframe16to pivot to the right with the subframe16.

The Cutting Unit Suspension

Each cutting unit28is coupled to mower frame4by a suspension30that lifts and lowers cutting unit28out of and into contact with the ground, respectively. Suspension30also provides cutting unit28with three degrees of freedom along orthogonal x, y and z axes to allow each cutting unit to individually follow the contours of the ground. Because suspension30is identical from one cutting unit to another, the description of suspension30in conjunction with one cutting unit28will suffice to describe suspensions30for all cutting units28. As depicted inFIGS. 3-8, suspension30is shown in the position in which cutting unit28has been lowered into its operative cutting position with cutting unit28in rolling contact with the ground.

Suspension30includes an upper suspension arm32and an underlying lower suspension arm34. In the top plan view, each arm32,34is shaped like an A with a wider rear end and a narrower front end. Each arm32,34has a truss like beam structure and is preferably cast or formed as an integral one piece part. In other words, upper arm32is a first one piece part and lower arm34is a second one piece part that is separate from upper arm32.

Each arm32,34has generally the same A shape in the top plan view and may be referred to as an “A arm” because of this A top plan shape. However, arms32,34have different side elevational shapes with lower arm34having a fairly pronounced, downwardly facing, U-shaped gooseneck36near the front end thereof. This allows the front of lower arm34to nest closer to the underside of the front of upper arm32than at the rear. In other words, the fronts of arms32,34are vertically closer together than the rears of the arms32,34. SeeFIG. 5.

Each side of each arm32,34at the rear thereof includes a circular bore38that extends generally in a vertical plane. The front of each arm32,34has a similar bore38that extends generally in a horizontal plane when cutting unit28is disposed in its operative cutting position. Pivot bushings40having a spherical seat (not shown) in the interior thereof are disposed in each of these bores38. Thus, bushing40at the front of each arm32,34will be generally horizontal when cutting unit28is in its operative cutting position and bushings40at either side of the rear of each arm32,34will be generally vertical. These orientations of bushings40have been found to be most effective in absorbing the typical impact shocks experienced by cutting unit28during cutting of the grass.

Bushings40at the rear of each arm32,34are pivotally journalled on a pair of transversely outwardly extending rear ball joints42r. The bushings40and ball joints42on which they are received, whether used at the front or rear of each arm32,34, have the structure disclosed in U.S. Pat. No. 7,144,182, which patent is hereby incorporated by reference. Rear ball joints42rfor each arm32,34are aligned with one another to form a common, transversely extending, substantially horizontal pivot axis. In this respect, the spherical head of each ball joint42ris received within the interior spherical elastomeric or polymeric seat of bushing40. Thus, upper arm32pivots on mower frame4about a first horizontal pivot axis denoted as x1. Similarly, lower arm34pivots on mower frame4about a second horizontal pivot axis denoted as x2. SeeFIG. 5. Note that rear ball joints42rfor only upper arm32have been shown inFIGS. 3-7with rear ball joints42rfor lower arm34having been omitted from the figures for the purpose of clarity.

Bushing40at the front of each arm32,34is pivotally journalled on a vertically extending front ball joint42fin the same manner as for bushings40and rear ball joints42r. Instead of being fixed to mower frame4, however, front ball joints42ffor the arms are clamped in place to a steering head44. Referring toFIGS. 6 and 7, steering head44includes a somewhat planar vertically extending body46. Body46has a pair of rearwardly extending, transversely spaced posts48that terminate in longitudinal pods or hubs50at the rear thereof.

Front ball joints42fare secured to the backside of body46of steering head44with the ball portion of the ball joint42ffor upper arm32extending downwardly from body46as shown inFIG. 7. The clamp that fixes this ball joint42fto the backside of body46has been removed inFIG. 7for the purpose of clarity. Front ball joint42ffor lower arm34is similarly mounted to the backside of body46, but is inverted such the ball portion of that ball joint extends upwardly into bushing40at the front of lower arm34.FIG. 8. depicts the inverted relationship of the two front ball joints42frelative to one another. The upper and lower arms32,34are connected together for joint rotation about their respective pivot axes x1and x2since the fronts of the arms are each connected to a single common piece, namely to steering head44as shown inFIG. 5.

As further shown inFIG. 5, when cutting unit28is in the operative cutting position, front ball joints42fand their stems are aligned on a yaw pivot axis to allow cutting unit28, which is carried beneath steering head44, to steer or yaw about a yaw pivot axis denoted as z. This allows cutting unit28to better turn or track over the ground during turns of mower2without skidding or dragging cutting unit28over the turf. The yaw pivot axis z forms one degree of freedom of motion for cutting unit28. The yaw pivot axis z has a particular angle or inclination relative to vertical that will be described in more detail hereafter in the section hereof entitled Negative Caster Angle.

Referring now toFIGS. 10 and 13, suspension30further includes a generally U-shaped cutting unit carrier frame52. Carrier frame52extends transversely across the width of cutting unit28and has a pair of downwardly extending vertical pitch arms54at either end thereof. Carrier frame52is, in reality, a number of different parts that are clamped together when cutting unit28is installed and is in its operative cutting position. In another aspect of this invention, these parts can be unclamped to easily remove cutting unit28from mower2as discussed hereafter in a section entitled Easily Removable Cutting Unit. However, for the purposes of describing suspension30of cutting unit28, carrier frame52and pitch arms54are, in effect, rigidly fixed relative to one another to move together as a single unit when cutting unit28is installed on mower2.

Referring now toFIG. 13, carrier frame52is pivotally attached to steering head44by a pair of front rigid links56fand a pair of rear rigid links56r. The upper ends of front links56fare pivotally attached to the front ends of hubs50on posts48of steering head44and the upper ends of rear links56rare pivotally attached to the rear ends of hubs50on posts48of steering head44. Similarly, the lower ends of the front and rear links56f,56rare pivotally secured to the front and back of carrier frame52. The links56f,56rin each pair are inclined relative to one another as taught in U.S. Pat. No. 7,191,584, owned by the assignee of this invention, which patent is hereby incorporated by reference. This allows cutting unit28to roll or pivot side to side about a horizontal longitudinal roll axis indicated as y inFIG. 13. This provides the second degree of freedom for cutting unit28.

The third degree of freedom for cutting unit28is provided by the connection of the lower ends of pitch arms54to cutting unit28itself. As also shown inFIG. 13, the lower end of each pitch arm54has a pivot hub58. Pivot hubs58are pivotally connected to cutting unit28about the axis of the rotatable cutting reel60of cutting unit28. Pivot hubs58of pitch arms54together define a horizontal transverse pitch axis indicated as x inFIG. 13, which pitch axis is the same as the axis of rotation of cutting reel60. Thus, cutting unit28, which is not itself shown inFIG. 13, can pivot or pitch fore and aft about the pitch axis by rocking fore and aft between pitch arms54.

A lift and lower actuator62, such as a hydraulic cylinder, is pivotally connected between mower frame4and upper arm32. Referring toFIG. 5, when the actuator arm64is retracted into the cylinder of actuator62, upper arm32is pivoted about its pivot axis x1(as is lower arm34about its pivot axis x2since lower arm34is connected to upper arm32through steering head44) in a clockwise direction shown by the arrow B inFIG. 11A. This raises steering head44to lift cutting unit28off the ground. Extension of actuator arm64from the cylinder has the opposite effect, namely a lowering of steering head44and cutting unit28relative to the ground.

Referring now toFIGS. 11A-11C, suspension30lifts cutting unit28from its cutting position on the ground as shown inFIG. 11Ainto a raised transport position as shown inFIG. 11C. Cutting unit28is placed into the transport position when the operator wishes to drive mower2from one location to another at a transport speed that is higher than the cutting speed at which mower2is driven when cutting grass.

Suspension30allows cutting unit28to approach and depart the ground in a preferred tail down position as shown inFIG. 11B. Thus, when cutting unit28lands on the ground, it lands first on the rear roller66rof cutting unit28and then pivots downwardly about rear roller66runtil front roller66ftouches the ground last. Similarly, when cutting unit28lifts off the ground, front roller66fdeparts first, cutting unit28then pivots upwardly about rear roller66r, and rear roller66rleaves the ground last.

The tail down approach and departure of cutting unit28happens because the center of mass of cutting unit28is behind the pitch axis x of pitch arms54. Thus, when cutting unit28first lifts off the ground, cutting unit28first pitches or rocks rearwardly relative to pitch arms54until pitch arms54engage against a stop (not shown) on some portion of mower frame4of cutting unit28. At that point, the pitching action of cutting unit28stops with cutting unit28being maintained in the tail down position. InFIG. 11B, cutting unit28is shown having rocked back in the direction of the arrows C with the frame of cutting unit28having stopped out against pitch arms54. However, this tail down orientation of cutting unit28relative to the ground is not itself new in the reel mower art. Prior Toro reel mowers have done the same thing.

However, in addition to maintaining the tail down orientation of cutting unit28relative to the ground in landing or departing the ground, suspension30also does something quite unique. In lifting further upwardly into the transport position, namely in going from the intermediate position shown inFIG. 11Bto the transport position shown inFIG. 11C, cutting unit28actually begins to level out into a more horizontal orientation. This is due to a retrograde or opposite rotation of steering head44on the fronts of upper and lower arms32,34. As upper and lower arms32,34rotate in the direction of the arrow B, steering head44is actually rotated oppositely in the direction of the arrow D inFIGS. 11B and 11C. After pitch arms54lock against the frame of cutting unit28, this opposite rotation D then pivots cutting unit28from its tail down position back to a more level position while simultaneously moving cutting unit28back closer to the front wheel.

WhileFIG. 11Cshows cutting unit28not completely level, suspension30could be designed to bring cutting unit28even more level if steering head44is rotated further forwardly in the direction of the arrow C. In addition, another approach would be to use some type of biasing force from springs (not shown) that would help accomplish this. For example, springs (not shown) could be used between steering head44and lower arm34to help center steering head44to face directly forwardly after cutting unit28reaches the transport position if steering head44and cutting unit28are initially skewed or canted about the yaw axis z at the beginning of the lifting operation. Such centering springs (not shown) would be arranged to push against steering head44on either side of a longitudinal centerline through steering head44. This pushing action would also bias steering head44further forwardly in the direction of the arrow D, with steering head44pivoting further forwardly due to the flex in bushings40, to level out cutting unit28even more than is shown inFIG. 11C.

Regardless of how level cutting unit28gets in the transport position thereof as shown inFIG. 11C, there is no doubt that it becomes more level and that it moves rearwardly with the rear roller66rof cutting unit28getting closer to the adjacent wheel6f. This allows the vertical height of rear roller66rabove the ground, indicated as h inFIG. 11C, to increase by a couple of inches over what would have occurred had the tail down orientation been maintained in the transport position, e.g. the height h above the ground increases from 2 inches or so to 4 inches or so. This extra clearance helps cutting unit28avoid hitting ground obstacles and the like as mower2drives over the ground with cutting unit28in the transport position while allowing cutting unit28to be conveniently lifted by pivoting about a horizontal, transverse pivot axis x1. Prior art mowers often pivoted or folded the cutting units about horizontal, longitudinal axes in order to provide sufficient ground clearance in transport, but this creates its own set of problems including exposing the undersides of the cutting units while in transport.

In addition, as the cutting unit28moves into its transport position, the cutting unit is moved or tucked in rearwardly towards the wheel6with the fore-and-aft clearance between the two, indicated as c inFIG. 11C, decreasing. When this happens with each of the two front cutting units28fin relation to the front wheels6f, the stability of mower2in transport is improved. It decreases the moment arm between the center of mass of cutting unit28fand the rotational axis of the adjacent front wheel6f, thereby decreasing the tipping force exerted on mower2by front cutting units28fwhen all of the cutting units28are in their transport position. This enhances stability of mower2when going up or down hills and the like. It decreases or potentially even eliminates the need for counterweights carried on mower frame4.

In moving between the various positions shown inFIGS. 11A-11C, the pivot axes x1and x2of upper and lower arms32,34remain fixed to mower frame4and remain fixed relative to each other. However, it is desirable to provide cutting unit28with an even more elevated service position in which cutting unit28is tilted up at a relatively steep angle to expose the underside of cutting unit28for service or maintenance. Such a service position is illustrated inFIG. 11D. As shown inFIG. 11D, the operator or a mechanic has greater access to and ability to reach front and rear rollers66, the rotatable cutting reel60, and the bedknife of cutting unit28. For example, with cutting unit28in the service position shown inFIG. 11D, it is fairly easy to remove the bedknife for sharpening or adjustment or to remove and replace front and rear rollers66.

In going between the transport and service positions shown inFIGS. 11C and 11D, respectively, actuator arm64of lift and lower actuator62is retracted even further into the cylinder while lower arm34is released from its fixed attachment to mower frame4. In other words, the two rear ball joints42r(not shown) that pivot lower arm34on mower frame4are normally fixed to mower frame4by a latch (not shown) that engages a yoke (not shown) that carries rear ball joints42rfor lower arm34. This locked or latched condition for lower arm34is the condition that occurs when cutting unit28is in its operative cutting position or its transport position or in any intermediate position between the cutting and transport positions. The latch is disengaged from the yoke when actuator arm64is retracted further into the cylinder to begin putting cutting unit28into the service position.

The disengagement of the latch can occur in many ways. As shown inFIG. 6, actuator arm64of the cylinder has a front clevis68that is pinned by a pin (not shown) to a flange70on upper arm32. This pin also passes through a pair of apertured tabs72on a rotatable latch release74carried on mower frame4beneath upper arm32. SeeFIG. 7. When actuator arm64is moved from its transport to its service position, actuator arm64acting through the pin and tabs72finally rotates latch release74far enough to release the latch that locks or fixes the yoke holding the two rear ball joints for lower arm34to mower frame4. When this occurs, the rear of lower arm34and the two rear ball joints therefor can now move off the pivot axis x2about which they normally rotate and will move forwardly and pivot in an arc about the pivot axis x1of upper arm32. This forward movement of the rear of lower arm34is depicted by the gap g that forms between the rear of lower arm34and the pivot axis x2as shown inFIG. 11D. Rear ball joints42rfor upper arm32that define the pivot axis x1are always fixed in place on mower frame4.

In any event, releasing lower arm34for movement relative to mower frame4when actuator arm64is retracted over its final range of travel allows lower arm34to move forwardly and pivot upwardly as needed about the pivot axis x1to permit cutting unit28to rise and dramatically tilt or incline into the service position thereof. When actuator arm64is extended to move cutting unit28from its service position back down to its transport position, the latch can be spring biased to automatically reset itself and relatch the yoke that holds rear ball joints42rfor lower arm34to mower frame4with rear ball joints42ragain aligned on axis x2when the transport position is reached. Thus, cutting unit28is lifted by a single lift and lower actuator from its usual cutting position in contact with the ground, through a raised transport position, and on into a raised and inclined service position, and vise versa, simply by extending or retracting actuator arm64of actuator62through different ranges of travel.

While a service position is desirable, it is not necessary and could be deleted in the design of suspension30. If the service position were deleted, then the structure that permits the service position to be reached, such as the latch that is released to release the rear ball joints42rfor lower arm34, could be deleted and the rear ball joints42rfor lower arm34would be fixed to some portion of mower frame4. Alternatively, one could avoid using the service position simply by restricting the stroke of actuator arm64to the range of travel needed to go between the cutting and transport positions only. Thus, the service position can be considered to be an optional feature.

Various pushbutton or other controls can be employed on control console14to allow the operator to power actuator62through any desired range or ranges of travel. For example, one button could be provided for going from cutting to transport and another button could be provided for going from transport to service. In addition, unlatching the latch that fixes or holds the rear of lower arm34to mower frame4, and relocking the latch, is done automatically as actuator arm64extends and retracts. The operator is not required to manually remove or reinstall a manual latch.

Suspension30for cutting unit28comprises a pair of durable A arms that are pivotally coupled to mower frame4and to steering head44that carries cutting unit28by a plurality of durable bushings40and ball joints42. Such bushings and ball joints permit any twisting that is needed as suspension30is lifted and lowered between its various positions. In addition, the arms32,34and the rest of suspension30are configured to allow a tail down landing or take off orientation of cutting unit28relative to the ground while also providing a more level and more rearward orientation of cutting unit28relative to the adjacent wheel6of mower2in the transport position, all while lifting and lowering cutting unit28by pivoting cutting unit28about a transverse pivot axis on mower frame4. Finally, cutting unit28can be simply and easily placed into a more inclined and more elevated service position without requiring any action on the part of the operator other than to continue to retract actuator arm64.

Negative Caster Angle

As explained earlier, the yaw axis z provided by front ball joints42fof upper and lower arms32,34when cutting unit28is in its operative, lowered cutting position is not strictly vertical. Instead, the yaw axis is inclined or canted relative to the vertical at a caster angle denoted as a inFIG. 5. This caster angle is a negative angle within the range of about 5° to 10°, and preferably about 6° or so, meaning that the angle of inclination points rearwardly relative to cutting unit28and relative to a vertical reference line as one proceeds downwardly along the angle of inclination. Known prior art reel cutting units have caster angles that are either precisely vertical (a zero caster angle) or are at a forward angle (a positive caster angle), namely an angle that points forwardly as one proceeds downwardly.

The Applicants have found that using a negative caster angle prevents the side of cutting unit28on the inside of a turn from dipping or wanting to dip down towards the ground (due to the overturning moment on the cutting unit from the suspension) during a turn of mower2and during a corresponding turn of cutting unit28. For example, when mower2is a riding greensmower as depicted herein, mower2is often used in a clean up pass around the margins of the green after the middle of the green has been mowed in a plurality of back and forth straight passes on the green. In such a clean up pass, mower2is turned or guided all the way around the periphery of the green to mow the grass at the periphery. In prior art greensmowers with positive or zero caster angles on cutting units28, the suspension tended to force the side of cutting unit28on the inside of the turn down towards the ground, causing the cut grass swath to have a slight, uneven washboard effect or pattern. Given the low heights of cut at which greensmowers cut grass, and given the desire for perfection of the mowed surface on the green of a golf course, this washboard effect or pattern is not desirable.

Now, with the negative caster angle disclosed herein, the force of the ground acting on the rollers of cutting unit28during a turn, causes the side of cutting unit28on the inside of the turn to remain level during turns. In effect, the negative caster angle disclosed herein tends to cause the side of cutting unit28on the inside of the turn to rise up an amount that counteracts the overturning moment from the suspension This avoids the washboard effect or pattern noted earlier and is, therefore, desirable.

Easily Removable Cutting Unit

Referring now toFIGS. 12-15, cutting unit carrier frame52, as noted earlier, comprises a plurality of parts that can be clamped and unclamped from one another to ease the task of installing or removing cutting unit28from mower2. With respect to this aspect of the invention, carrier frame52comprises a cross member76, a cross rod78, and the pitch arms54that are carried at either end of cross rod78. Cross rod78and pitch arms54carried by cross rod78are obviously now separate parts from cross member76of carrier frame52. In other words, pitch arms54are not integrally connected to cross member76as they are in the assignee's prior U.S. Pat. No. 7,191,584. Rather, pitch arms54are carried on a separate cross rod78and such pitch arms54will be fixed or connected to cross member76only when cross rod78is connected to cross member76. This can be done in this invention in a quickly and easily attachable and detachable manner to allow cutting unit28to be easily removed from mower2.

As shown inFIGS. 12 and 15, the underside of cross member76has a plurality of downwardly facing, U-shaped notches80at either end thereof. The top of cross rod78fits up into notches80. In addition, as shown inFIGS. 13 and 14, cross member76has a pair of clamps82disposed at either end thereof.

As shown inFIG. 15, each clamp82includes a pivotal clamp body84that is pivotally journalled on a first pivot pin86carried on cross member76. Clamp body84carries a pivotal J-shaped hook88on a second pivot pin90. When clamp82is closed, hook88of clamp82is positioned underneath cross rod78to receive cross rod78and to draw cross rod78tightly up against notches80in cross member76. When clamp82is open, hook88has been released from engagement with cross rod78and has been rotated out of the way of cross rod78to release the clamping engagement of cross rod78to cross member76.

Clamp body84includes a rearwardly extending tab or finger92to allow the user to manually open clamp82by rotating clamp body84about first pivot pin86by pushing up and forwardly on finger92in the direction of the arrow E inFIG. 15. Assuming clamp82was closed to begin with when this happens, the rotation of clamp body84causes hook88to lower and drop out of its clamping engagement against the bottom of cross rod78. Once hook88has released cross rod78in this manner, the user can then flip hook88forwardly out of the way of cross rod78. If the user then pushes down and rearwardly on the raised finger92in the direction of the arrow F inFIG. 15to reversely rotate clamp body84relative to cross member76, hook88will then be elevated but will not catch or clamp beneath cross rod78. In fact, in the open position of clamp82, the user can even manually flip hook88all the way up so that it is resting vertically upright or even lying atop finger92. Referring toFIGS. 13 and 14, an open clamp82is illustrated on the left of cross member76and a closed clamp82is illustrated on the right of cross member76.

To relock clamps82in their clamping orientation, the user first pushes up and forwardly on finger92in the direction of the arrow E and flips hook88down to allow the J-shaped end of hook88to get beneath cross rod78. Then, with hook88positioned to catch against cross rod78, the user simply pushes down and rearwardly on finger92in the direction of arrow F to close clamp body84and to draw hook88upwardly into a tight locking or clamping relationship to cross rod78. Thus, clamps82disclosed herein are one form of a simple, manually operable clamp adapted for temporarily clamping cross rod78of carrier frame52to cross member76of carrier frame52. Other types of clamps or temporary securing devices could be used.

When clamps82are both released, cutting unit28, including that portion of suspension30comprising cross rod78and pitch arms54attached to cutting unit28, can separate from the rest of suspension30. This separation is depicted inFIG. 14. It is preferred that there be an upward biasing force of a small amount, e.g. 5 pounds, on upper and lower arms32,34of suspension30. Thus, as soon as clamps82are released, the rest of suspension30will lift slightly above cutting unit28far enough to clear cross rod78and pitch arms54. The operator or mechanic can then very easily roll cutting unit28out from under upper and lower arms32,34to remove cutting unit28.

Installing cutting unit28is a simple reversal of the above steps. The operator or mechanic rolls cutting unit28back into place beneath upper and lower arms32,34and positions cross rod78beneath cross member76. Then, the operator or mechanic takes both hands and pushes down on opposite ends of cross member76until notches80on cross member76engage against the top of cross rod78. While holding this downforce, the operator or mechanic can then close clamps82by pushing down on fingers92in the direction of the arrow F using his or her thumbs until clamps82have tightly clamped cross rod78to cross member76. The installation is then complete.

The manner in which cutting unit28can be easily removed and installed is unparalleled in the mower art. When any grass baskets140are removed from cutting units28, the two front cutting units28fare completely accessible from the front. So, too, is center rear cutting unit28rafter pivotal footrest22pis flipped to the side, as described earlier. To remove any cutting unit28, the operator or mechanic simply has to release two clamps82with a couple flicks of the wrist and without requiring any tools. No attachment bolts or screws have to be laboriously unbolted or unscrewed. Once clamps82are unclamped, the upward bias on the rest of suspension30causes suspension30to simply lift on its own up above cutting unit28which remains on the ground. The operator or mechanic can them simply roll cutting unit28forwardly to get it out from under suspension30and to remove it from mower2. Cross rod78that remains on cutting unit28forms a convenient handle for rolling cutting unit28out. Removal of a cutting unit, which was a laborious and difficult process in many cases in the prior art, now takes only a few seconds.

Easily Removable Cutting Unit Motor

Cutting unit28carries a motor94of some type, typically a hydraulic motor though electric or other motors could be used. Such motors are often coupled to one of the side plates96of the frame of cutting unit28. Some type of drive connection extends between the drive shaft of the motor and the shaft of rotatable cutting reel60carried on cutting unit28. As the drive shaft of the motor is rotated, the shaft of cutting reel60rotates. Thus, the helical blades of cutting reel60sweep the standing grass against a sharpened cutting edge of the bedknife to shear the standing grass off at whatever height of cut is determined by the vertical position of front and rear rollers66relative to the frame of cutting unit28. Rollers66that are in relatively raised positions relative to the cutting unit frame mean lower heights of cut and rollers66that are relatively in lowered positions on the cutting unit frame mean higher heights of cut.

As a part of the service friendly nature of mower2of this invention, motor94used on cutting unit28, whether such motor94be a hydraulic motor as shown, an electric motor, or some other type of motor, is easily and quickly removable from the frame of cutting unit28. This aspect of the invention is shown inFIGS. 16-20. An electric motor94eis depicted inFIG. 16while a hydraulic motor94his depicted inFIGS. 17-20.

Referring first toFIG. 20, motor94has an enlarged attachment flange100at one end. Flange100has a pair of bores102on either side of motor94. One bore102on flange100is illustrated inFIG. 20, the bore102on the other side of motor94being obscured. The drive shaft104of motor94can be seen inFIG. 20since motor94is not yet assembled to the frame of cutting unit28. In the past, motors of this type have most often been simply directly mounted or bolted to side plate96of the frame of cutting unit28using attachment bolts that pass inwardly through the bores102on flange100of motor94and into corresponding openings106in side plate96.

Motor94as depicted inFIGS. 17-20does not show the hydraulic hose connections thereto. These extraneous portions of motor94, which are not essential to understanding the quickly removable nature of motor94, have simply been removed fromFIGS. 17-20.

Instead of using attachment bolts or screws, motor94is attached to side plate96using a pivotal wire form112and a cradle114having a pair of seats116for coacting with portions of wire form112to hold motor94against side plate96of cutting unit28. As shown inFIG. 20, cradle114is shaped like a horseshoe with two upwardly extending legs118. Cradle114is not integrally formed as part of motor94, though it could be. Preferably, cradle114is a separate piece from motor94and thus can be used with existing motors from many manufacturers without the need for retooling or redesigning standard, readily available motors. Thus, there is a cost advantage to making cradle114a separate piece from motor94since it allows common, off the shelf motors94to be used to power cutting unit28. However, cradle114is preferably removably fixed to motor94or to attachment flange100by retaining ring(s) (not shown) so that cradle114does not fall off motor94during installation and removal of motor94.

As shown inFIG. 20, legs118of cradle114on the backside each have an alignment pin120that fits through one of the bores102on flange100and then into an opening106therefor on side plate96of the frame of cutting unit28. In a sense, the alignment pins120are like the attachment bolts in the prior art except that they only align cradle114to flange100and to side plate96of the frame of cutting unit28instead of securing the parts together. The front side of each leg118of cradle114is shaped to have an upwardly facing, inclined lip122forming an open edge of a generally semi-circular seat116. Seat116is below a curved cam124located at the top of each leg118of cradle114. Curved cam124and seat116with the upwardly inclined lip122can best be seen inFIGS. 18-20.

Wire form112has a U-shaped central grip126having a pair of generally vertical legs128that terminate in lower ends. Legs128of grip126are not straight as they extend vertically, but have a couple of inclined sections therein. Similarly, the top130of grip126is not horizontal, but is formed with a slight V-shape. In any event, grip126further includes a horizontal locking pin132at the lower end of each of the vertical legs128of grip126. Locking pins132extend transversely outwardly. Locking pins132are the portions of wire form112that will be received in seats116formed in cradle114when motor94is held on or assembled to side plate96of the frame of cutting unit28.

Wire form112is pivotally attached to side plate96of the frame of cutting unit28by a U-shaped section134of wire form112connecting each side of grip126to side plate96. The U-shaped sections134of wire form112extend in planes that are generally perpendicular to the plane of grip126of wire form112. The legs136of each U-shaped section134can be compressed towards one another or pulled away from one another to some degree and the U-shaped section134can have a small amount of rotation relative to side plate96at the end138where it is clamped to side plate96. This movement in the U-shaped sections134of wire form112is sufficient to allow the locking pins132of wire form112to be placed into or pulled out of seats116in cradle114.

As shown inFIG. 16, motor94has been assembled onto side plate96with cradle114having been slid in and abutted against flange100on motor94. Locking pin132on each of the vertical legs128of grip126is received in the upwardly facing, semi-circular seat116atop the upwardly inclined lip122thereof with grip126extending up above and around motor94of motor94. In this position, each locking pin132is below curved cam124on cradle114. The force of wire form112and the engagement of the locking pin132on either side of motor94within seat116on either side of cradle114are sufficient to tightly hold motor94to side plate96of the frame of cutting unit28.

If the user wishes to remove motor94from cutting unit28, the only thing the user need do is to reach down, place his or her hand on top130of grip126and pull firmly upwardly on grip126. As the user does so, the U-shaped sections134of wire form112can pivot or flex enough to allow the locking pins132to be forced up past the curved cams124on cradle114until the locking pins have risen past curved cams124. At this point, there is nothing holding cradle114to side plate96. Thus, motor94can simply be slid off to the side of side plate96as indicated by the arrow G inFIG. 19.

The hydraulic hose or other drive connections to motor94will also have to be removed, either prior to or after the disconnection of motor94from side plate96, if motor94is to be completely removed and swapped out with another motor. However, if motor94can remain attached to the hydraulic hoses or drive connections at least temporarily, the disconnection of such hoses or connections may not be necessary. Motor94can simply be slid off and laid to the side of cutting unit28with the hoses or drive connections still attached. But, in either case, motor94can be simply and quickly disconnected from cutting unit28by pulling up on grip126of wire form112to disengage wire form112from seats116formed in cradle114.

It is similarly easy to reattach motor94. To do this, cradle114as carried on flange100has its alignment pins120passing through bores102in cradle114.The assembled cradle114and motor94are abutted against side plate96with the alignment pins120passing into the openings106therefor on side plate96. Then, the user need only grab top130of grip126and push down on grip126. This will flex and pivot the U-shaped bottom sections134of wire form112sufficiently to allow the locking pins132to be cammed over the cam surfaces124with locking pins132finally snapping into seats116provided on cradle114. When this occurs, the force of wire form112will hold motor94firmly in place on cutting unit28.

As can be appreciated, removing and attaching motor94to cutting unit28now takes only seconds. In conjunction with the quick and easy attachment and removal of cutting unit28from mower2, the operator or mechanic's task in providing service is made vastly easier. Cutting unit28can be pulled out and removed very quickly and without tools by opening two clamps82. Once this is done, motor94driving cutting reel60can be removed from cutting unit28simply by pulling up on grip126of wire form112, again without using any tools, and by then sliding motor94off to the side. The laborious bolting and unbolting known in the prior art is no longer required for either task.

Obviously, when both of these quick removal features are used together on the same mower2, the ease of service is enhanced to its fullest extent. However, either feature could be used independently of the other. For example, one could use the easy removal feature of cutting unit28using the two clamps82on a cutting unit28not having the quick removal of motor94provided by wire form112, and vise versa.

The Grass Basket With Balanced Cutting Unit Weight Distribution

Each cutting unit28can be equipped with a grass basket140that may be optionally attached to cutting unit28for collecting grass clippings generated by the operation of cutting unit28. As is typical in many prior art reel cutting units, grass basket140is mounted forwardly of rotatable cutting reel60of cutting unit28. Grass clippings are thrown or deflected forwardly from cutting reel60to be collected in grass basket140. Periodically, grass basket140may be removed from cutting unit28for dumping of the grass clippings at some disposal or dump location. Cutting unit28can be operated without grass basket140attached thereto if the operator does not wish to collect the grass clippings.

Grass basket140is supported on a grass basket support member142that is itself pivotally supported on cutting unit carrier frame52. Grass basket support member142is U-shaped having a transverse cross beam144and pair of upwardly and forwardly extending support arms146. Cross beam144includes an outwardly extending trunnion148at either end. Each trunnion148is rotatably received in a pivot hub150carried at either end of cross member76of carrier frame52. SeeFIG. 12for an illustration of trunnions148and pivot hubs150in an exploded, non-assembled relationship relative to each other.

Pivot hubs150are carried on arms152that extend rearwardly from cross member76of carrier frame52as best shown inFIG. 26. Pivot hubs150define the pivot axis of grass basket support member142, which is indicated as x4inFIGS. 4,23,24and26. Pivot axis x4is located rearwardly of cross member76of carrier frame52.

Support arms146of grass basket support member142have a pair of outwardly extending support pins154that are each aligned on a common axis indicated as x5inFIGS. 23,24and26. Referring toFIGS. 24 and 25, the rear of grass basket140has a pair of slotted fingers156that fit around support pins154to attach grass basket140to grass basket support member142. The top of the basket includes a top hand grip157. Top hand grip157, in conjunction with a bottom hand hold158molded into the bottom of grass basket140near the front thereof as shown inFIG. 22, allows the operator to lift grass basket140off mower2or to place grass basket140onto mower2.

Two pivotal latches160are used to lock or secure grass basket140onto support pins154of grass basket support member142. Pivotal latches160, only one of which is shown inFIGS. 24 and 25, are operated by a pivotal latch release162that is carried under top hand grip157. Latch release162can be squeezed in the direction of the arrow H inFIG. 25by the operator's hand when the operator is gripping top hand grip157. When latch release162is so gripped and squeezed, pivotal latches160rotate up and out of contact with support pins154as shown by the one latch160that can be seen inFIG. 25. This releases grass basket140for removal from or installation on support pins154. When latch release162is not being gripped and squeezed by the operator, spring biasing on latch release162causes latches160to rotate downwardly until they engage against and lock on support pins154to secure grass basket140to support pins154. This is what retains grass basket140on grass basket support member142.

FIGS. 23-25show top hand grip157, slotted fingers156, latches160and latch release162separated away from the basket portion of grass basket160, but only for the sake of clarity. Normally, the hand grip157, slotted fingers156, etc. are carried on and united with the basket portion as shown inFIGS. 3,4,27and28.

In any event, when grass basket140is attached to and carried by grass basket support member142, it is in a position to catch grass clippings being generated by cutting unit28and thrown forwardly into grass basket140through an open rearwardly facing mouth141of grass basket140. SeeFIG. 24. As the clippings accumulate in grass basket140, the weight of grass basket140naturally increases. However, that weight is transferred to cutting unit28at the connection of the pitch arms54to the cutting unit28.

As noted earlier, the pitch arms54connect to the cutting unit28around the axis of rotation of the cutting reel60. The axis of rotation of the cutting reel69is midway or substantially midway between the rotational axes of front and rear rollers66of cutting unit28. Accordingly, the weight of grass basket140is equally distributed between front and rear rollers66. In other words, as the weight of grass basket140increases, the amount of weight seen by front roller66fincreases by an amount equal to the increase seen by rear roller66r. Front roller66fdoes not become more heavily loaded than rear roller66r.

This equal weight distribution between front and rear rollers66is preferred since it helps minimize any change in the quality of the cut that might occur from the increasing weight of grass clippings in grass basket140. The mower designer usually takes into account the weight distribution of cutting unit28when grass basket140is not attached, or at least when grass basket140is empty, when attempting to achieve the best quality of cut that is possible. With grass basket140in place, the quality of cut will be adversely affected by the weight of grass basket140and particularly by the dramatically increasing weight of grass basket140as it fills with clippings. This adverse affect is undesirably magnified if front roller66fis more heavily loaded with the basket weight than rear roller66r. By keeping the weight distribution substantially equal between front and rear rollers66, the adverse changes in the quality of cut that occur with an increasing basket weight are kept to a minimum.

The Counterbalanced Grass Basket

While adverse changes in the quality of cut from increasing grass basket weight can be minimized as noted above, such changes are not eliminated. Cutting unit28will have one quality of cut when grass basket140is empty or not installed on cutting unit28and a second quality of cut when grass basket140is fully loaded with perhaps30or more pounds of grass clippings. Keeping this weight equally distributed between front and rear rollers66is a desirable thing to do.

To eliminate any adverse changes in the quality of cut from increasing grass basket weight for a grass basket140that is carried on cutting unit28, a further improvement has been added to mower2to deal with this increasing weight. This improvement comprises an active counterbalance system that increases the upward biasing force on upper and lower arms32,34of cutting unit suspension30for each 5 pound increment of change in the weight of grass basket140. This improvement is an optional addition to the balanced weight distribution feature noted earlier. For example, a more basic or standard mower would be equipped with the balanced weight distribution and a more deluxe or premium mower would be equipped with both the balanced weight distribution and the active counterbalance system that will now be described.

The active counterbalance system will be described first with reference toFIGS. 8 and 9. A plurality of counterbalance torsion springs164are located on a portion of mower frame4on the pivot axis x2of lower arm34. Springs164are located between rear ball joints42rof lower arm34. However, springs164remain on the pivot axis x2and do not move with rear ball joints42rof lower arm34when lower arm34moves off pivot axis x2when cutting unit28is being lifted into the service position thereof. Springs164always remain in place on pivot axis x2.

Referring toFIG. 9, springs164are located around a pivotal adjustment shaft166that is rotatably journalled in that portion of mower frame4that mounts springs164. One end168of each spring164is hooked into a slot170in shaft166. The other end172of spring164is free and is adapted to simply abut against some portion of lower arm34of suspension30. Thus, suspension30will be biased upwardly by the abutting engagement of the free ends172of spring164against lower arm34with the amount of the biasing force depending upon how tightly wound springs164are around shaft166. The more tightly wound, the higher the biasing force.

A counterbalance actuator174extends between mower frame4and a pivotal link176that is attached to one end of shaft166. Actuator174can comprise either a hydraulic or an electric actuator or the like. Actuator rod178is pivotally connected to the lower end of link176. As actuator rod178is extended, link176and shaft166are rotated in the direction of the arrow J inFIG. 9to more tightly wind springs164around the axis of shaft166.

Actuator rod178is automatically extended in concert with the increase in weight of grass basket140. The extension occurs without requiring the operator to manually control or activate actuator174. A load sensor (not shown) of some type is positioned between grass basket support member142and cross member76of carrier frame52. For example, grass basket support member142has a central, upwardly extending, forwardly facing channel180forming a generally cylindrical housing182at the upper end thereof. SeeFIGS. 21 and 26. This housing182on grass basket support member142is directly behind and faces a similar housing184located at the center of cross member76of carrier frame52. The load sensor can be arranged within and between these two housings182and184to, in effect, be sandwiched between the two.

As grass basket140fills with grass clippings and its weight increases, grass basket140and grass basket support member142will pivot forwardly about the pivot axis x4in the direction of the arrow K inFIG. 26. This will compress the load sensor between housing182on channel shaped member180on grass basket support member142and housing184on carrier frame52. The compression of the load sensor is an indication of the amount of the weight increase of grass basket140. The load sensor sends a signal to some type of controller (not shown) on mower2so that the weight of grass basket140is monitored by the controller.

As noted previously, springs164are initially set to provide a small amount of upward biasing force on upper and lower arms32,34even when grass basket140is empty. Thus, when grass basket140is removed and cutting unit28is disconnected from mower2, upper and lower arms32,34rise up above cutting unit28to allow the operator or mechanic to simply roll cutting unit28out. This aspect was previously discussed in the section hereof entitled Easily Removable Cutting Unit.

Now, as grass basket140increases in weight when grass clippings are being deposited therein, for every 5 lb increase in the weight of grass basket140, as detected by the load sensor and monitored by the controller, the controller will send an adjustment signal to actuator174to wind up springs164an amount sufficient to provide an additional 5 lbs of upward spring biasing force on upper and lower arms32,34of actuator174. This will balance out the increase in the weight of grass basket140and return the weight of cutting unit28on the ground to its designed nominal amount, whatever that might be. In other words, the weight of cutting unit28as it rolls over the ground is kept substantially constant with the increase in weight of grass basket140not being transmitted onto cutting unit28. Instead, this increase in weight is being constantly monitored and counterbalanced in 5 lb. Increments by the active counterbalance system just described.

It would be possible to detect smaller or larger increments of weight increase as the trigger for making an adjustment in the force provided by springs164. The adjustment could even be done on a substantially continuous basis, though this is not preferred because the system would be almost constantly making an adjustment in spring force. An increment of 5 lbs. has been found by the Applicants herein to not be so large as to dramatically adjust the quality of cut provided by cutting unit28. Thus, even allowing the weight of grass basket140to increase 5 lbs. before making an adjustment in springs164will not appreciably adversely affect the quality of cut.

In addition, the counterbalance system can be used to compensate for changes in the cutting unit weight depending upon whether an electric motor94eor a hydraulic motor94his used to power cutting reel60. Electric motors94eare typically heavier than hydraulic motors94h. Thus, if a heavier electric motor94eis installed, the counterbalance system can be initially set to provide more upward biasing force on the suspension than in the case of when lighter hydraulic motor is installed in an amount sufficient to counteract the increase in weight of the heavier electric motor94ecompared to the hydraulic motor. In other words, the suspension should ultimately provide the same nominal net upward biasing force on cutting unit28regardless of variations in weight of the cutting unit28that result from changes in the weight of the motor94that is installed on cutting unit28.

It would be possible on mower2to delete the active counterbalanced grass basket feature. If this were to occur, then it would not be necessary to make grass basket support member142a separate member from cross member76of carrier frame52, trunnions148and150would no longer be needed such that the pivot axis x4of grass basket support member142would disappear, and the housings182,184, the load sensor, and the counterbalance actuator174would be deleted. In this event, some type of support arms146and/or support pins154would still be used to support grass basket140on carrier frame52, but such support arms146and support pins154would be fixed to some remaining portion of carrier frame52, such as cross member76. Even if the active counterbalanced grass basket feature were deleted, some counterbalance springs would most likely still be used to provide an upward counterbalance force on suspension30, if for no other purpose than in connection with the Easily Removable Cutting Unit described earlier, i.e. to allow suspension30to lift slightly when a cutting unit28is unhooked from suspension30.

The Dual Pivot Axes of the Grass Basket

Grass basket140is actually provided with two pivot axes. The first pivot axis is the axis x4of grass basket support member142relative to carrier frame52that carries cutting unit28. This is the pivot axis about which grass basket140rotates or pivots as it fills with grass. This is the pivot axis about which the pivoting motion of grass basket support member142is detected and sensed by the load sensor as the weight indication used in the active counterbalance system described in the preceding section hereof.

However, grass basket140is also free to pivot, at least in a clockwise direction as indicated by the arrow L inFIGS. 23 and 24, about support pins154which attach grass basket140to grass basket support member142. The axis x5of support pins154is actually a second pivot axis for grass basket140. Grass basket140can only pivot in the clockwise direction L about the axis x5as pivoting in the other direction is substantially prevented during normal operation of mower2. This is due to the fact that grass basket140normally rides against pitch arms54of suspension30to provide controlled clearance of a lower lip186of mouth141of grass basket140relative to cutting reel60. This aspect of mower2will be discussed hereafter in the section hereof entitled Controlled Grass Basket Clearance to the Cutting Reel.

As grass basket140fills with grass and its weight increases, grass basket support member142can pivot about the axis x4to accommodate this increase in weight and allow grass basket140counterbalance system noted earlier to function. This rotation about the axis x4in the direction of the arrow K is accompanied by a very slight rotation of grass basket140about the axis x5in the direction of the arrow L. In other words, as the weight of grass basket140increases and grass basket support member142pivots, grass basket140and grass basket support member142will jackknife slightly about the axis x5to permit this pivoting motion of grass basket support member142in the direction of the arrow K.

Pivot axis x5of grass basket140is further forward and substantially above the pivot axis x4of grass basket support member142. This is important given the fact that the front of grass basket140is significantly forward of cutting unit28when grass basket140is attached to cutting unit28. Thus, when mower2encounters a sharp change in elevation, such as when mower2descends a hill and then comes to a flat surface at the bottom of the hill, or vise versa, grass basket140will experience the change in elevation before the rest of mower2. In other words, the front of grass basket140will hit the flat surface while the rest of mower2is still on the hill.

If only the pivot axis x4were present and because basket140does not pitch with cutting unit28, the forward propulsive force of mower2on grass basket140would tend to drive grass basket140into the ground at the change in elevation or into the flat surface in the example above. This would roll grass basket140forwardly against the ground, thereby damaging grass basket140by jamming it into the ground or potentially damaging the rest of mower2. This is obviously undesirable.

However, when the above noted change in elevation scenario occurs, the presence of the other pivot axis x5that is forward and higher than the pivot axis x4permits grass basket140to pivot in the direction of the arrow L to accommodate the transitory transition at the change in elevation. Thus, when grass basket140is driven against the flat surface in the example noted above, grass basket140can sharply pivot or jackknife in the direction of the arrow L. When the rest of mower2and cutting unit28reach the flat surface, then this temporary sharp rotation will reverse until grass basket140reestablishes contact with pitch arms54of cutting unit28. The presence of the second pivot axis x5thus permits mower2to drive over sharp elevational changes between a hill and a flat surface, or at elevational changes in a swale, with grass basket140pivoting about the pivot axis x5as need be to accommodate this.

Controlled Grass Basket Clearance to the Cutting Reel

Grass basket140is attached to cutting unit28by grass basket support member142that is carried on carrier frame52for cutting unit28. Carrier frame52is located downstream of two of the three axes of freedom about which cutting unit28can move in adapting to changes in ground contour. In other words, carrier frame52is located below or downstream of steering head44, which provides freedom in the z or yaw axis, and is below the pairs or rigid inclined links56, which provide freedom in the y or roll axis. Thus, grass basket140inherently yaws or rolls with cutting unit28and maintains a constant clearance relative to cutting unit28about the y and z axes.

However, cutting unit28is free to pitch about the x axis and the problem remains of how to keep lower lip186of mouth141of grass basket140at a fairly constant and small clearance relative to cutting reel60. If this clearance is not controlled and kept substantially constant, then grass clippings can dribble out from between grass basket140and cutting reel60and be deposited in unsightly lumps on the mowed turf surface. For example, if cutting unit28can pitch or rock back and forth about the x axis while grass basket140does not, the gap between lower lip186of grass basket140and cutting reel60will obviously grow or shrink depending upon the direction of the rocking of cutting unit28. The clearance will vary and at times will be so large that grass clippings can easily escape down through this clearance.

The Applicants have solved this problem by taking advantage of the fact that the weight of grass basket140, even when empty and also when filled with clippings, tends to rotate grass basket140down toward cutting unit28in the direction of the arrow K about the pivot axis x4. Grass basket140is allowed to swing down about the pivot axis x4until portions of grass basket140, namely the lower triangular portions188of the side walls of grass basket140adjacent to lip186, abut against the front of the lower ends of pitch arms54. This is shown inFIG. 28. When this occurs, the lower lip186of mouth141of grass basket140will be maintained a very short distance, e.g. only an eighth of an inch or so, ahead of the nominal diameter of a new or unworn cutting reel60. The nominal diameter of a new or unworn cutting reel is indicated as d inFIG. 28.

Now, when cutting unit28pitches back and forth relative to the ground about the pitch axis x, the clearance between lower lip186of mouth141of grass basket140and the diameter d of cutting reel60will remain substantially constant. This is due to the fact that pitch arms54, or more precisely the pivot hubs58of pitch arms54, are aligned with the axis of rotation of cutting reel60so that the axis of rotation of cutting reel60is the same as the pitch axis x. Thus, even though cutting unit28rocks relative to the pitch axis x, pitch arms54and the front edge thereof have a constant unchanging relationship to the pitch axis x and thus to the axis of rotation of cutting reel60. By abutting a portion of grass basket140against the front edge of pitch arms54, lower lip186of mouth141of grass basket140will stay at the same relative clearance as is desirable even when cutting unit28pitches back and forth about the pitch axis x.

The effect of this is to prevent the clearance between lower lip186of mouth141of grass basket140and the outer diameter of cutting reel60from varying. This clearance is kept substantially constant and can be kept very small to improve the flow of grass clippings from cutting reel60into grass basket140. There is little or no opportunity for grass clippings to fall through this gap or clearance. Thus, the after cut appearance of the mowed turf is improved since grass clippings will be more effectively collected in grass basket140and will not fall out onto the turf. This is particularly important at the previously noted low heights of cut prevailing on golf greens and given the extreme desire of golf course operators for a clean and uniform appearance of the mowed turf on a golf green.

In the event mower2did not have a counterbalance feature as described in earlier herein, pivot axis x4would be deleted. Grass basket140would then pivot about pivot axis x5to cause the abutting engagement of portions188with pitch arms54. Alternatively, if pivot axis x5were not available, some other horizontal pivot axis for grass basket140would need to be provided on cutting unit carrier frame52or on some other portion of suspension30. In addition, the controlled grass basket clearance feature could be deleted if desired in which case grass basket140would be supported on cutting unit carrier frame52in a manner that would cause the spacing between the lip141and cutting reel60to vary as cutting unit28pitches about the pitch axis.

The Interleaved Sides of the Grass Basket and the Cutting Unit

Finally, referring toFIGS. 12,21and23, side plates96of the frame of cutting unit28are no longer directly joined to the top wall of the frame of cutting unit28as in prior art mowers. Instead, top wall190of cutting unit28is part of a U-shaped grass shield192in which top wall190extends between and is directly joined to a pair of vertically extending side shields194at either end of top wall190. These side shields194extend downwardly to a level slightly below the top of cutting reel60. Side shields194are transversely spaced apart by a distance wider than cutting reel60so that the top of cutting reel60can nest between side shields194of grass shield192. Side plates96are joined or fastened to grass shield192by a plurality of fastening bolts that connect the rear of side plates96to the vertical side shields194of grass shield192at locations generally rearwardly and/or above cutting reel60.

This allows a front slot196to be formed between side shields194and the adjacent side plates96of cutting unit28with such a gap or slot196being present on each side of cutting unit28. Pitch arms54are located in this slot196. When cutting unit28pitches back and forth about the pitch axis x, pitch arms54are free to move back and forth in slot196. As noted earlier, at some point during the lifting of cutting unit28from its operative cutting position to its raised transport position, the movement of pitch arms54within slot196will get stopped out to lock up cutting unit28relative to the rest of suspension30. But, at least during operation of cutting unit28in a normal mowing mode, pitch arms54can move rather freely within slots196as cutting unit28pitches back and forth.

Now, it would be possible for the side wall portions188of grass basket140to engage against the lower ends of pitch arms54even if slots196between side shields194and side plates96were not present. This is true because the sides of grass basket140need engage only against the lower ends of pitch arms54. However, the Applicants have chosen to make slot196open to the front and to use the separate U-shaped grass shield192for a reason. Namely, the side wall portions188of grass basket140can be made to telescopically fit into or to be interleaved into slots196. This interleaving is shown best inFIGS. 3,22, and27where the triangular lower side wall portions188of grass basket140fit between the side shields194and side plates96on each side of cutting unit28.

This interleaving engagement between side shields194of grass shield192and the adjacent side plate96further improves the after cut appearance of the mowed turf since it presents a more tortuous path for the escape of the grass clippings from inside grass shield192of cutting unit28. For grass clippings to escape to the side of cutting unit28from inside grass shield192, the clippings now have to travel around the front edge of side shield194, then pass rearwardly about the interleaved side wall portion188of grass basket140, then around the rear edge of the interleaved side wall portion188of grass basket140, and then forwardly back along the length of the interleaved side wall portion188of grass basket140before such clippings can pass out around the front edge of side plate96. Such a tortuous path makes it highly unlikely the many grass clippings can escape through this path. Thus, fewer grass clippings can leak out through the sides of cutting unit28but will be effectively collected in grass basket140. This is an additional improvement that can be utilized to keep as neat and clean an appearance for the mowed turf as is possible.

Use on Other Reel Mowers

The features described above can be used on reel mowers other than the one specifically shown inFIGS. 1 and 2. For example, the various grass basket improvements would be useful on a walk reel mower, such as a walk greensmower, having an upwardly and rearwardly extending handle assembly that is gripped by an operator who walks behind the mower. Such a walk reel mower would typically have only a single cutting unit carried at the front of the mower frame. Thus, the grass basket improvements could be used in conjunction with the greensmower shown in U.S. Pat. No. 7,191,584 incorporated by reference herein, or on similar greensmowers. Similarly, the reel cutting unit of a walk greensmower can be easily removable from the suspension, and/or the motor can be easily removable from the frame of the reel cutting unit, both as also disclosed herein.

Moreover, the various features disclosed herein need not all be used at the same time on a single mower. The mower designer can pick which features a particular mower should have on an almost ala carte basis. Thus, there are many possible permutations of features that would desirably be of interest.

Accordingly, the scope of this invention shall be limited only by the appended claims.