CA1282967C - Turf maintenance apparatus - Google Patents

Abstract

Abstract A rotary mower (10) including a front deck assembly (18) and a pair of wing decks (20). Each wing deck (20) is supported by a lift arm assembly including a main lift arm (26) and a lift arm extension (32). A pivot joint (30) exists between lift arms (26) and (32) so that when deck (20) is raised from its cutting position to its transport position it is also caused to rotate so that mower (10) maintains a relatively low profile even when decks (20) are in their transport position. Mower (10) also preferably includes a pair of breakaway assemblies (48) which allow wing decks (20) to "break away" in the event they strike an immovable object. Finally, a preferred mower (10) includes resilient bushing assemblies (38) between the wing deck lift arm assemblies and the wing deck housings (24) to minimize vibration and noise and provide some floating of the decks (20).

Description

29~

IMPROVED TURF MAINTENANCE APPARATUS

Technical Field The invention relates generally to tu~f maintenance equipment, and more particularly to methods and apparatus for supporting cutting units of power turf mowers.

Backqround of the Invention Altho~gh the present invention can be applied to a wide variety of turf maintenance equipment, one particularly advantageous application is power turf mowers. Many types of power turf mowers are known. Such equipment can generally be classified according to the type of cutting unit(s). Typically, the cutting units of a turf mowing machine are either of the rotary, reel or flail type. Reel units are normally used for high precision cutting situations whereas flail units are normally used in severe situations such as roadside mowing. Rotary units, on ~he other hand, are u~eful over a wide variety of conditions.
Therefore, although the present invention could be used in conjunction with turf maintenance machines and haLvesters of any type, for the sake of brevity the invention will be - 2 - ~ 7 described in ~erms of a turf mowing machine having one or more rotary cutting units or deckfi.
Power turf mowing equipment can al~o be categorized based on the method of propelling the cutting unit.
Generally, there are walk-behind riding: and towed cutting unit mowers. The present invention relate6 to the latter two types, and particularly to riding mowers; walk-behind mowers are usually found in residential settings, and the present invention does not pertain to such mowers. Thus, for the sake of brevity the invention will be described in terms of riding rotary mowers.
Larger rotary riding mowers typically include a traction vehicle supported by a plurality of wheels: a prime mover connected through a transmission to one or more of the wheels; one or more rotary decks having mechanically or hydraulically driven blades; and ons or more lift arms (or analogous structures) pivotally connected to the traction vehicle 6uitable for supporting the deck(s). Lift arms are so termed because they lift the decks from their normal operating positions to their transport positions, a~ further discussed below. The present invention involves methods and apparatus for supporting cutting units, and more particularly, lift arms and related structures and systems.
More particularly, the present invention is directed toward methods and apparatus for supporting cutting units in their lowered operative positions and in their rai6ed "transport"
positions, and for raising and lowering cutting units between the two extremes.
The preferred characteristics or feature6 of a cutting unit support 6ystem vary depending on whether the cutting unit is in it6 cutting position or in its tran6port position. In the cutting position, the cutting units are preferably "floated" relative to ~he traction vehicle. That is, the cutting units are preferably independently and separately sllpported by the traction vehicle so they can follow the contours or undulation6 of the ground ~Z9~
irrespectiYe of the gros6 motion of ~he ~r~ction vehicle.
If cutting units are not supported in a floating manner, ~hey tend to scalp the higher regions and miss the lower regions. While non-floating cutting units might be acceptable for residential use, certainly golf course and estate maintenance require that the cutting units individually follow the subtle variations of the ground to maintain a consi6tently good cut across the entire swath, regardle6s of the immediate topography encountered by each individual cutting unit.
In addition to floating, applicants perceive that cutting units should be attached to the traction vehicle such that they are not permanently damaged if they should collide with an immovable object, such as a tree, during operation. When the cutting units of prior art mowers encountered immovable objects during mowing opera~ions, they or their support structures, or both, were oftentimes severely damaged. Applicants perceive that cutting units should be mounted such that they can temporarily "breakaway"
from their normal operating positions in the event of such an impact. Further, the cutting units should be easily reset into their normal positions following the collision.
Another preferred feature of a cutting unit support sy6tem is the ability to support a wing or outboard cutting Z5 unit such that its outermost tip is readily observable by the operator, permitting the wing decks to be used for precise trimming. While this feature may seem obvious at first glance, prior art machines have generally not provided it, presumably because if the wing decks extend laterally outward from the operator's seat the operator's side-to-side vision is greatly reduced when the decks are in their raised transport positions. Reference is made to Figures lB and 2~3, which show prior art units and the extent to which the operator's field of vision is reduced in transport mode.
Figure lB illustrates a mower of the type sold by Jacobsen under the HR-15 designation; and Figure 2B illustrates a .

6~
mower of the type ~old by Howard Price under the ~ydro-Power 180 designation. The operator~ fi side-to-~ide vision i6 almost completely blocked with the HR-15; whereas 60me side-to-side and some rear vision are blocked by the wing decks of the Hydro-Power lBO.
The connection between the cutting unit~ and the traction vehicle must also permit, if not as6i6t, lifting of the cutting units from their lowered cutting positions to their raised tran6port positions. The operator might want to temporarily raise one or more of the cutting units to mow a narrower swath or to pass through a gate or between trees. Al60, it is occasionally necessary to drive mowing machines over conventional road surfaces, at which time it i6 important to raise the cutting units to a transport position since they are not entirely suitable for repeatedly running up and down over curbs, nor for travel over paved streets at anything approaching the speed of ordinary city traffic. In view of this, most riding mowers, such as the one described in U.s. Patent 2,299,859, include mechanis~s which can raise ~he cutting units upward and toward the traction vehicle.
Once the cutting unit is raised into its transport position a preferred support sys~em provides several important features. For example, when a cutting unit is in its raised or transport position, it must be held there very securely. Otherwise, it may tend to swing or rock and thereby cause personal injury or damage to the mower. For mowers having hydraulically-operated lift arms, additional mechanical latches or locks have traditionally been used to hold the lift arms in their raised or transport positions.
This is due to the fact that some hydraulic cylinders are incapable of holding lift arms and cutting units in their raised positions because of hydraulic fluid leakage over a period of time.
A6 noted above, when the cutting units are in their raised transport positions the operator ~hould preferably 2~
still have a 360 field of vision. Reference is again made to the prior art design~ of Figures lB and ~B.
Also, when the cutting units are in their raised positions the center of gravity of the entire machine should not be too high, for otherwise the machine will not be able to safely negotiate sidehill6 and the like. Particularly for a front drive, rear steer mower, some of the weiqht of the wing decks should be borne by the rear wheels when the machine i8 in its transport mode, for otherwise the back end of the mower can literally lift off the ground when the mower i6 6uddenly stopped for any rea60n. Prior art machines were not well balanced in the transport mode. For example, little if any of the weight of the HR-15 wing decks (see Figure lB) is borne by the rear 6teerable wheels.
Finally, Applicants perceive that when the lateral or wing cutting unit6 are raised the overall width of the mower should preferably be less than the width of the fron~ deck to permit close trimming with the front deck only. Figures lA and ZA show top views of the HR-15 and Hydro-Power 180 mower~ with the decks in transport mode. Of particular note i6 the fact that the raised wing decks extend beyond the outer edges of the front decks, thus hindering trimming.
The present invention addresses the problems associated with prior art cutting unit support systems. In particular, the cutting unit support system of the present invention accommodates deck floating and breakaway in the cutting position; and securely holds the cutting units, maintains a relatively low center of gravity, and maximizes the operator's field of vi6ion in the transport position.

Summary of the Inve_tion~

Accordingly, one embodiment of the invention broadly includes a system suitable for use with a mower for operatively connecting a wing cutting unit to a traction 6 - ~2~2~

unit, including a main lift arm assembl~ pivotally connec~ed to the traction unit: "lift arm extension mean6" for pivotally connecting the main lift arm assembly to the cutting unit; means for raising the lift arm a6sembly and lift arm extension means ~uch that the wing cutting unit moves from a cutting position to a transport position; and means for pivoting the lift arm extension mean6 and the cutting unit relative to the main lift arm assembly as the main lift arm a~embly and lift arm exten~ion are raise~
relative to the traction unit, whereby the cutting unit is simultaneously raised and rotated relative to the traction unit 80 that the mower pos6esses a reasonably low center of gravity when the cutting unit is in its transport position and ~o that operator field of vision is not significantly reduced.
Another embodiment of the invention broadly includes a system for supporting a cutting unit in relation to a traction unit, including a lift arm assembly and a resilient bushing assembly suitable for coupling the lift arm assembly and the cutting unit to provide a degree of give between the assemblies, whereby vibration and noise are reduced and the cutting unit can float relative to the traction unit.
Still another aspect of the invention is a breakaway assembly for use with a wing deck cutting unit. That is, Z5 one aspect o the invention is a system for supporting a wing cutting unit relative to a traction unit, including a lift arm assembly pivotally connected to the traction unit and the cutting unit, wherein the cutting unit can "yaw"
relative to the traction unit; a breakaway assembly; and means ~or connecting the breakaway assembly to the cutting unit and to the traction unit, wherein during normal use the breakaway assembly doesn't come into play, but when the cutting unit strikes an immovable object the breakaway assembly separates to prevent damage to the cutting unit.
Additional features and aspects of the invention are described in detail below with reference to the Drawings.

Brief Description of ~e Drawin~s The invention will be further de6cribed with reference to the Drawings, wherein:
Figure lA is a top view of a first prior art turf mowing machine in the transpor~ mode;
5Figure lB is a side elevational view of the mower of Figure lA in its transport mode;
Figure lC is a top plan view of the mower of Figure lA
in its cutting mode:
Figure 2A is a top view of a second prior art turf mowing machine in the transport mode:
Figure 2B i6 a side elevational view of the mower of Figure 2A in its transport mode;
Figure 2C is a top plan view of the mower of Figure 2A
in it!s cutting mode;
15Figure 3 is a perspective view of a mower according to the present invention:
Figure 4A is a top view of the mower of Figure 3 in its transport mode;
Figure 4B is a side elevational view of the mower of Figure 3 in its transport mode Figure 4C is a top plan view of the mower of Figure 3 in its cutting mode Figure 5A is an enlarged partial perspective view of a portion of one of the wing deck support systems of the mower of Figure 3;
Figure 5B is an enlarged sectional view taken generally along line 5B - 5B of Figure 5A;
Figure 6A is an enlarged partial perspective view of another portion of the wing deck support system of Figure 3, including the tie rod and breakaway assembly:
Figure 6B is an enlarged elevational view, partly in section, o the tie rod and breakaway assembly of Figure 6A
Figure 6C is a sectional view of the breakaway assembly of Figure 6A, taken generally along line 6C - 6C;

~ ~32~36'7 Figure 7A is an enlarged perspectiYe view of one of the wing decks of the mower of Figure 3, showing in particular the bushing support system;
Figure 7B is an enlarged sectional view of one of the bushing assemblies of the bushing support system shown in Figure 7A taken generally along line 7B - 7B; and Figure 8 is a partial perspective ~iew of one of the wing decks of the mower shown in Figure 3, and its support system, in vaLious positions.

Vetailed DescriPtion of ~he Invention With reference to the Drawing6, wherein like reference numerals designate like parts and assemblies throughout the 6everal views, Figure 3 shows a per6pective view of a mower lO according to the invention. Mower lO includes a traction vehicle 12 supported by a pair of front drive wheels 14 and a pair of rear steerable wheels 16. Traction vehicle 12 also carries a prime mover connected through a transmission to drive wheels 14. Traction vehicle lZ supports a front deck 18 and a pair of wing decks 20a and 20b, the blades of which are driven either hydraulically or through a power take-off (PTO) to the prime mover. The decks 18, 20 are shown in their cutting positions in solid line: and in their transport positions in phantom line. Front deck 18 includes a front deck housing 22. Wing decks 20 include wing deck hottsings 2~. Wing decks 20a and ZOb and their supporting structures are symmetrical about the longitudinal centerline o~ mower lO. Therefore, only deck 20a and its supporting members, shown in Figure 3, will be described in any detail.
Pivotally connected to each side of traction vehicle 12 is the near end of a main wing deck lift arm 26. Operating each main wing deck lift arm 26 is a double-acting cylinder 28 attached at one end to traction vehicle 12 and at the g ~LZ~

other end to main lift arm 26. At the far end of each main wing deck lift arm 26 is a pivot/cam as6embly 30 which include~ a pivot joint between main wing deck lift arm 26 and a lift arm extension 32, as further discus~ed below.
The far end of lift arm extension 3Z terminates in a U-6haped bracket 34 which in turn pivotally supports a substantially horizontal (in the cutting mode) roll member 36. Roll member 36 is connected by mean~ of four bushing assemblies 38 to a pair of housing strut6 40 which are in turn rigidly connected to hou6ing 24. Struts 40 are rollably supported at either end by caster6 42 which are ground following devices establishing the height of cut of deck 20. Extending toward traction vehicle 12 from lit arm extension 32 is a tie rod bracket 44, and extending between traction vehicle 12 and tie rod bracket 44 is a tie rod ~6 which includes a breakaway assembly 98, the function of which is further discussed below.
As further described below, deck Z0 can "float"
relative to traction vehicle 12. That is, as casters 42 follow ground undulations struts 40 and housing 24 also "pitch," "roll," "yaw," and translate vertically depending on the terrain. Deck 20 is permitted to roll from side to side, primarily because roll member 36 can substantially freely pivot relative to roll member pivot bracket 34 when deck 20 is in its cutting position. Bushing assemblies 38 also permit some motion of struts 40 and housing Z~ relative to roll member 36 and therefore contribute to the floating of deck Z0. Further, bu6hing assemblies 38 ab~orb bo~hersome vibration, thus reducing noise and fatigue of the various components of mower 10. Bushing assemblies 38 also permit a limited amount oP l'pitching" and "yawing" of housing 2~ relative to roll member 36, and ultimately relative to traction vehicle 12. Limited vertical movement of deck 20 is accommodated by main wing deck lift arm 26 which can pivot to some degree relative to traction vehicle 12 when deck 20 is in its cutting position.

Double-acting cylinder 28 can be controlled by a hydraulic sy~tem powered by the prime mover. The hydraulic system can include one or more manually-operated selector valves which ean be manipulated to cau~e double-acting cylinder 28 to act on main wing deck lift arm 26 to raise, lower, lock or "float" 5partially counterbalance) deck 20.
One such hydraulic system is generally disclosed in U.S.
Patent ~,307,559. While this patent does not disclose u6e of a double-acting cylinder, a pair of single-acting cylinders could be used in lieu of double-acting cylinder 28. Either a double-acting cylinder or a pair of single-acting cylinders is neces6ary because main wing deck lift arm 26 mu6t be raised and lowered under power because of it6 inherent 6tability in the cutting and transport modes, as further discussed below. Front deck 18 and its supporting structure can be rai6ed, lowered and floa~ed relative to traction vehicle 12 using a standard hydraulic system. The present invention is primarily directed toward wing deck configuration, arrangement and support.
Therefore, front deck 18 and its attendant parts will not be described in any detail.
Each of the major components of wing deck 20 and its support structure is described below.

Breakaway AssemblY 48 As discussed above, breakaway assembly q8 is included as part of tie rod 46. During normal cutting, tie rod 46 and breakaway assembly 48 extend between traction vehicle 12 and tie rod bracket 44 and 6ub6tantially prevent pivoting of lift arm extension 32 relative to main lift arm 26 and "yawing" of wing deck as6embly 20, except Eor the limited yawing motion provided by bushing as6emblies 38. However, when wing deck as6embly 20 6trikes an immovable object, e.g., a tree, breakaway as6embly 48 release6 and allow6 tie 2~r~7 rod ~6 to immediat~ly lengthen to minimize the shock associated with ~he impact. The structure of breakaway assembly ~8 i8 described below.
Figure ~A shows an enlarged partial perspec~ive view o tie rod g6 and breakaway assembly 48 and the means (i.e., ball joints) b~ which these components connect to traction vehicle lZ and tie rod bracket 44. Figure 6B shows an enlarged partially sectioned view of tie rod 96 and breakaway assembly 48. As 6hown in the Figures, breakaway assembly 4B includes two basic subassemblies, a male assembly 50 adjustably connected to the portion of tie rod 46 extending from tie rod bracket 44; and a female assembly 52 connected to the portion of tie rod 46 extending from traction vehicle 12.
~ith particular reference to Figure 6C, a sectional view of breakaway assembly 48, male assembly 50 includes an element 54 threaded on tie rod ~6 having a necked-down region forming a pair of ramp surfaces 56. Connected to elemen~ 54 on the end opposite from tie rod 46 and axially aligned therewith is a hex rod 58 at the far end of which is a stop nut 60 and a stop washer 62 (see Figure 6B), the function of which is described below.
Female ~ssembly 5Z includes several "stationary"
components which are rigidly connected to tie rod 46. One of these components is an inner tube 64 which is adjus~ably connected to tie rod 46 by means of an inner tube extension 66 and a lock nut 68. At the far end of inner tube 6~
(opposite end from lock nut 68) is a pivot block 70 which includes a central aperture suitable for slidably receiving hex rod 58 oE male assembly 52. Sliding on the outside of inner tube 6~ is an outer tube 72 which forms an outer tube leaf flange 74 at one end and an outer tube spring flange 76 at the opposite end. Pivot block 70 pivotally supports first and second leaves 78a and 78b at first and second leaf pivot points 80a and 80b, respectively. At the distal ends of leaves 78 are rollers ~2. At the pro~imal ends of leaves .
,.

~q z~
78 are contact ~urface~ 84 which bear against outer tube leaf flange 74. Finally, a compres ion spring 86 compres6ively engages an adjustment nut 88, which is threaded onto inner tube extension 66, and outer tube spring flange 76.
The operation of breakaway assembly 48 can now be described. During normal use of mower 10 compression spring 86 provides enough force aqainst outer tube 72 to sub6tantially prevent pivoting of leave6 78. Therefore, ramps 56 on male element 59 cannot force leaves 78 open to allow the escape of element 54, and lift arm exten~ion 32 cannot pivot relative to main arm 26. However, when wing deck assembly 20 strike~ an immovable object, ramps 56 can separate leaves 78 in spite of the force provided by spring ~6 to a sufficient extent to allow male element 54 to escape leaves 78. However, the male and female halves 50 and 52 of breakaway assembly 48 cannot entirely separate, since stop washer 6Z eventually contacts the inner surface of pivot block 70 which slidably receives hex rod 58. A hex rod is used rather than a circular rod to ensure a consistent orientation of male assembly 50 relative to female as6embly 52. Male and female assemblies 50 and 52 can be reconnected by simply raising wing deck assembly 20 by appropriately energizing double-acting cylinder 28, but the proper orientation between the assemblies must be maintained, because male element 54 is not circular but is instead flat on two sides. It should be noted that the breakaway force can be adju6ted by turning nut 88 relative to inner tube extension 66 to increase or decrease the spring force.

Bush;nq As6emblie6 38 As noted above, four bushing as6emblies 38 are interposed between roll member 36 and housing struts ~0.
Figure 7A i~ an enlarged perspective view of wing deck - 13 - ~2~ 7 a~sembly 20 sho~ing the preferred location~ of bushing as6emblies 38. And, Figure 7B is an enlarged sectional view of one of the bushing assemblies 38. With reference to Figures 7A and 7B, bushing assemblies 38 are mounted on bu6hing assembly mounting plates 90 located at either end of roll member 36 and substantially perpendicular thereto.
Mounting plates 90 form holes at either end thereof to receive bushing as6emblies 38. All of the component6 of bushing as6embly 38 are axially aligned. Referring to Figure 7B, each bushing as6embly 38 include6 an inner bushing 92 and an outer bushing 94. Bu6hings 92, 94 are resilient, preferably rubber, and are substantially toroidal. Inner bushing 92 is located on the inside (toward bracket 34) of mounting plate 90 whereas outer bushing 94 is located on the outside (opposite from bracket 34) of mounting plate 90. Extending through the aperture fo~med by mounting plate 90 and inwardly concentric with inner and outer bushings 92 and 94 is a hollow sleeve 96. Sandwiching each bushing 92, 94 is a pair of metal washers 102 bonded to the rubber bushings 92, 94. And, extending through housing strut 40 and the other components of bushing assembly 38 ;s a bushing bolt 98. Bolt 98 and a bushing nut 100 connect the entire assembly together and to housing strut 40. It can therefore be seen that housing strut 40 can move to a degree relative to roll member 36. When it does 60, bushings 90, 94 compress or expand to provide some "give" so that deck 20 can float relative to traction vehicle 12 to follow the immediate terrain encountered by deck Z0.
Bushings 92, 94 can be purchased from Lord Corporation under the designation SSB Series Sandwich Mount. Bushing assemblies 38 allow housing 24 to yaw, pitch and roll relative to roll member 36. It should be noted that bushing assemblies 38 not only provide limited floating but also minimi~e vibration and noise. By providing some give between housing 24 and roll member 36, the remaining components of wing deck assembly 20 are subjected to less vibration.

_ 14 - ~Z~2~

Lift Arms 26, 32 and Pivot~Cam A6~emblY 30 Reference is now made to ~igures 5A, 5B and 8, where lift arms 26 and 32 and pivot~cam assembly 30 are shown in some detail. Figure 5A shows an enlarged per~pective view of a portion of the left wing deck assembly 20 as viewed from the rear: Figure 5B shows an enlarged view of pivot/cam a6sembly 30, partly in section; and Figure 8 diagrammatically illustratefi the motion of deck Z0 as it is raised from its cutting position to its transport position.
As can be seen, lift arm extension 32 pivots about main lift arm 26 at pivot point 104. The precise construction of joint 104 i6 not critical, and any conventional bearing assembly could be used. Pivoting about lift arm exten6ion 32, on the side opposite from breakaway assembly 48, i6 a substantially C-shaped pivot arm 106. A pivot joint 108 is established between these two components. At one end of the "C" is a cam follower 110; and at the other end of the "C"
is an upper ball joint 112. Extending downward from upper ball joint 112 is a pivot arm extension 114 which terminates with a lower ball joint 116 connected to housing 2~.
Pivot/cam assembly 30 includes a generally U-shaped cam bracket 118 situated at the distal end of main lift arm 26.
Cam bracket 118 internally forms a pair of arcuate three dimensional cam surfaces 120 which are quite separated at their outer ends and which converge toward their inner ends. ~eference is made to Figure 5B which sho~s the path of cam follower 110 along arcuate upper and lower cams 120.
At end 121 the distance between cam surfaces lZ0 is several inches, whereas the cams 120 are much closer at their ends 123. In fact, roller 110 has so much play at cam end 121 that deck hou6ing 2~ can roll about 20 side-to-side; and virtually no play at end 123. Thus, when deck assembly 20 is in its cutting position, as shown in solid line in Figure 3, there is a considerable amount of play of pivot arm 106 relati-~e to lift arm extension 32. The result is that - 15 - ~2~296~

housing 24 can pivot or "roll" to a considerable degree relative to lift arm extension 32 when deok a~sembly 20 i6 in i~s lowered or cutting position. As deck 20 i~ rai6ed, however, lift arm extension 3Z is pivoted relative to main lift arm Z6 about joint 104 such that cam follower 110 rotates into the converging cam surface6 lZ0, thereby progressively decreasing the play of pivot arm 106.
Ultimately, when the deck Z0 is in its fully rai~ed or transport position, as 6hown in phantom line in Figure 3, there can virtually be no movement of pivot arm 106 relative to lift arm extension 3Z which securely locks deck Z0 in its transport position relative to lift arm extension 32.
Pivot/cam assembly bracket 30 also forms an extension 122 which supports a rubber bumper 124. As shown in Figure 5B, bumper 124 functions to support and cushion lift arm ex~ension 32 when it rotates to it~ fullest extent relative to main arm 26, i.e., when the deck 20 in its transport position.
Figure a illustrates in diagrammatic fashion the motion Z0 of lift arms 26, 32 as deck 20 is raised from its cutting position to its transport position. As deck 20 i~ raised, tie rod assembly ~6 acts on tie rod bracket 49 to rotate lift arm extension 32 relative to main lift arm 26. This causes cam follower 110 ~o proceed into the converging cam formed by cam surfaces 120. Lift arm extension 32 continues to rotate relative to main lift arm 26 as deck 20 is raised until finally in the fully raised position lift arm extension 32 is as shown in Figure 8. It should again be noted that rotation of lift arm extension 32 relative to main lift arm 26 is due to the fact that tie rod assembly 46, 4a is longer than main lift arm 26 and as tie rod assembly 46, 9a and lift arm 26 are raised tie rod assembly 46, 4~ in effect pushes on tie rod bracket 44 to cause it to in turn rotate lift arm extension 32 relative to main lift arm 26. It should be noted that lift ar~. extension 32 rotates roughly 110 from the cutting position to the - 16 ~

transport position. It should also be noted that the leading edge of housing 24 i6 facing directly upward when the deck 20 is fully raised. Also, main lift arm 26 i6 actually rotated overcen~er when going from the cutting position to the tran~port po~ition so that it i~ stable and there is no need to rely on hydraulic cylinder 28 to maintain deck assembly Z0 in its transport position.
Referring to Figures 3 and 9B, it can be seen that since the wing decks 20 are not only raised but are also rotated the operator has a 360 field of view. It should also be noked that front deck housing 22 is the widest component of mower 10 when the wing decks are raised 60 that the front deck of mower 10 can readily be used for more precise trimming operations, in sharp contrast to prior art mowers. This is shown in Figure 4A (mower 10) and Figures lA and 2A (prior art). Finally, due to the fact that decks 20 are lifted and rotated into the transport mode, some of their weight is transferred to the rear wheels. This alleviates the problem of "rear wheel liftoff" during transport mode braking.
There are other modifications which will be apparent to those skilled in the art. Accordingly, the scope of this invention will be limited only by the appended claims.

Claims (14)

1. For use with a mower having a traction vehicle and a wing cutting unit, a system for supporting the wing cutting unit relative to the traction vehicle, comprising:

(a) a lift arm assembly suitable for pivotally interconnecting the traction vehicle and the cutting unit, wherein the cutting unit can yaw relative to the traction vehicle;

(b) a breakaway assembly; and (c) means for connecting the breakaway assembly to the cutting unit and to the traction vehicle, wherein during normal mowing operations the breakaway assembly prevents substantial yawing of the cutting unit relative to the traction vehicle but when the cutting unit strikes an immovable object the breakaway assembly releases to allow the cutting unit to yaw to prevent damage to the mower, and wherein the breakaway assembly can be automatically reset by raising the wing cutting unit with the lift arm assembly.

2. The wing unit supporting system of claim 1, wherein the breakaway assembly comprises a male assembly and a spring-loaded female assembly, wherein during normal mowing operations the spring force provided by the female assembly is sufficient to prevent an escape of the male assembly from the female assembly, but when the cutting unit strikes an immovable object the male assembly exerts sufficient force on the female assembly to overcome the spring force at which time the male assembly moves relative to the female assembly to cause a change in length of the breakaway assembly and a minimization of the impact and damage attributable thereto.

3. The wing cutting unit supporting system of claim 2, wherein the female assembly comprises a pair of leaves which are spring-loaded together and wherein the male assembly comprises a male element having a necked-down region and a pair of ramps extending therefrom, wherein when the cutting unit strikes an immovable object the ramps act on the spring-loaded leaves and if the force on the leaves is sufficient the male element escapes the leaves.

4. The wing cutting unit support system of claim 3, wherein following the escape of the male element from the female assembly the original configuration of the break-away assembly can be reset by raising the cutting unit, thereby causing the male element to automatically re-engage the female assembly.

5. The system of claim 4, wherein the male assembly further comprises a stop, wherein the male assembly cannot completely escape the female assembly in the event of an impact but wherein the breakaway assembly can lengthen to a predetermined extent to minimize the shock associated with the impact.

6. For use with a mower having a traction vehicle and a wing cutting unit, a system for operatively connecting the wing cutting unit to the traction vehicle and for moving the wing cutting unit from a cutting position to a transport position, wherein the cutting unit has a leading edge which faces forward when the cutting unit is in its cutting position, the system comprising:

(a) a main lift arm assembly;

(b) means for pivotally connecting the main lift arm assembly to the traction vehicle;

(c) lift arm extension means for pivotally connecting the main lift arm assembly to the cutting unit;

(d) means for raising the main lift arm assembly and the lift arm extension means such that the wing cutting unit moves from its cutting position toward its transport position; and (e) means for pivoting the lift arm extension means and the cutting unit relative to the main lift arm assembly as the main lift arm assembly and lift arm extension means are raised relative to the traction vehicle, wherein the cutting unit is simultaneously raised and rotated relative to the traction vehicle so that when the cutting unit reaches its transport position its leading edge substantially faces directly upward, whereby the mower possesses a reasonably low center of gravity and operator field of vision is not significantly reduced when the cutting unit is in its transport position.

7. The wing cutting unit connecting system of claim 6, wherein the cutting unit can yaw relative to the traction vehicle and wherein the pivoting means comprises a breakaway assembly and means for connecting the breakaway assembly to the lift arm extension means and the traction vehicle, wherein during normal mowing operations the breakaway assembly prevents substantial yawing of the cutting unit relative to the traction vehicle but when the cutting unit strikes an immovable object the breakaway assembly allows the cutting unit to yaw to prevent damage to the mower.

8. The wing cutting unit connecting system of claim 6, further comprising a resilient bushing assembly suitable for coupling the lift arm extension means and the cutting unit to provide a degree of give therebetween, whereby vibration and noise are reduced and the cutting unit can float to a degree relative to the traction vehicle.

9. In a mower having a traction vehicle and a wing cutting unit, wherein the wing cutting unit has a cutting position and a transport position and a leading edge which faces forward when the cutting unit is in its cutting position, a system for operatively connecting the wing cutting unit to the traction vehicle, comprising:

(a) a lift arm assembly pivotally connected to the traction vehicle and the cutting unit;

(b) means connected to the traction vehicle for selectively pivoting the lift arm assembly and cutting unit upward relative to the traction vehicle; and (c) means for rearwardly pivoting the cutting unit as it is pivoted upward, wherein when the cutting unit reaches its transport position its leading edge is substantially facing directly upward, whereby the mower possesses a reasonably low center of gravity and operator field of vision is not significantly reduced when the cutting unit is in its transport position.

10. For use with a mower having a traction vehicle and a wing cutting unit, a system for supporting the wing cutting unit relative to the traction vehicle, comprising:

(a) a lift arm assembly suitable for pivotally interconnecting the traction vehicle and the cutting unit, wherein the cutting unit can yaw relative to the traction vehicle; and (b) breakaway means for substantially preventing yawing of the cutting unit relative to the traction vehicle during normal mowing operations, and for yieldably releasing to allow yawing of the cutting unit when the cutting unit collides with an immovable object, thereby preventing substantial damage to the mower, wherein the breakaway means can be automatically reset by raising the wing cutting unit with the lift arm assembly.

11. A mower comprising:

(a) a traction vehicle;

(b) a cutting unit having a cutting position and a transport position and a leading edge which faces forward when the cutting unit is in its cutting position;

(c) a main lift arm pivotally attached to the traction vehicle suitable for pivoting in a substantially vertical plane, the main lift arm having a lower position corresponding to the cutting unit cutting position and an upper position corresponding to the cutting unit transport position;

(d) a lift arm extension pivotally connected to the main lift arm suitable for pivoting in a substantially horizontal plane relative to the main lift arm when the main lift arm is in its lower position;

(e) a resilient bushing assembly suitable for coupling the lift arm extension and the cutting unit to provide a degree of give therebetween, whereby vibration and noise are reduced and the cutting unit can float to a degree relative to the traction vehicle;

(f) means for raising the main lift arm and the lift arm extension such that the main lift arm moves from its lower position toward its upper position and the cutting unit moves from its cutting position toward its transport position;

(g) a breakaway assembly operatively connected to the traction vehicle suitable for pivoting the lift arm extension and the cutting unit relative to the main lift arm as the main lift arm and the lift arm extension are raised relative to the traction vehicle, wherein during normal mowing operations the breakaway assembly prevents substantial yawing of the cutting unit relative to the traction vehicle but when the cutting unit strikes an immovable object the breakaway assembly allows the cutting unit to yaw to prevent damage to the mower, and wherein the cutting unit is simultaneously raised and rotated relative to the traction vehicle so that when the cutting unit reaches its transport position its leading edge substantially faces directly upward, whereby the mower possesses a reasonable low center of gravity and operator field of vision is not significantly reduced when the cutting unit is in its transport position.

12. For use with a mower having a traction vehicle and a cutting unit, a system for supporting the cutting unit in relation to the traction vehicle, comprising:

(a) a lift arm assembly suitable for connection to the traction vehicle;

(b) a roll member connected to the lift arm assembly in such a way that the motion of the roll member relative to the lift arm assembly is limited to that of rolling from side to side; and (c) resilient means for connecting the cutting unit to the roll member, the resilient means resiliently allowing limited pitch and yaw of the cutting unit relative to the roll member and the lift arm assembly.

13. The cutting unit supporting system of claim 12, wherein the roll member is elongate and has first and second transversely-spaced ends; and the resilient means comprises first and second rubber bushing assemblies interposed between the roll member first and second ends, respectively, and the cutting unit.

14. The cutting unit supporting system of claim 13, wherein each rubber bushing assembly comprises a pair of longitudinally-spaced rubber bushings.