Gang-type rotary lawn mower

Abstract: A gang-type rotary lawn mower including a frame (12) supported by wheels for movement over the ground, a power source (18) which is mounted on the frame and which drives at least two of the wheels, an operator's seat (20) mounted on the frame, a steering system (22) enabling the operator to steer the lawn mower, at least two side-by-side front rotary cutting deck assemblies (34) mounted on the frame, the front deck assemblies defining a gap between adjacent front deck assemblies, and at least one rear rotary cutting deck assembly mounted on the frame behind the front deck assemblies, each rear deck assembly being aligned with a respective gap between adjacent front deck assemblies, each of the front and rear deck assemblies including a single-spindle mulching deck (38) defining a downwardly opening space, a single spindle (84) mounted for rotation about a generally vertical axis within the space, and at least one cutting blade mounted on the spindle for rotation therewith.

Description: BACKGROUND OF THE INVENTION The invention relates to rotary lawn mowers and to gang-type lawn mowers. Historically, reel mowers have been used to cut golf course roughs. An example of such a reel mower is disclosed in EP-A-0 569 836 in which a number of reel cutting units are connected to a frame of the reel mower by respective arms. The arms and the reel cutting units connected thereto can be urged in a downward direction by hydraulic cylinders. It is generally recognized that rotary mowers are better suited for cutting tall grass, where scalping is not a problem, while reel mowers are better for shorter cutting. A gang of reels can be either attached directly to the frame on which the operator rides, or pulled behind a tractor. Pull-behind or tow-behind rotary gangs are also known. These can be driven either by a power takeoff or by a separate engine. Tow-behind gangs, whether reel or rotary, are generally undesirable for cutting a golf course rough because close trimming is difficult. Thus, rotary mowers have not been used to cut golf course roughs, which require close trimming and the ability to cut undulating terrain at a relatively short length. SUMMARY OF THE INVENTION The invention provides a gang-type rotary lawn mower suitable for cutting a golf course rough. This is a tremendous improvement over the known prior art, because a rotary mower typically requires substantially less maintenance than a reel mower. The lawn mower has single-spindle cutting decks attached directly to the frame on which the operator rides, with a front row of two or more cutting decks in front of the front wheels, and with a rear row of one or more cutting decks between the front and rear wheels. The invention also provides an improved arrangement for mounting a rotary cutting deck on a lawn mower frame. Each deck is mounted on its own lifting arm so that the deck can move vertically relative to the frame and can pivot relative to the frame about three mutually perpendicular axes. More particularly, the invention provides a gang-type rotary lawn mower comprising a frame supported by front and rear wheels, an operator's seat mounted on the frame, at least two side-by-side front cutting deck assemblies mounted on the frame in front of the front wheels, and at least one rear cutting deck assembly mounted on the frame behind the front wheels and in front of the rear wheels. Each of the front and rear deck assemblies includes a pair of laterally-spaced, generally vertically-extending side plates, front wheels supporting the side plates for movement over the ground, and a rear roller extending between the side plates and supporting the side plates for movement over the ground. Each deck assembly also includes a single-spindle cutting deck located between the side plates and in front of the roller, the deck being mounted on the side plates such that the height of the deck relative to the ground is adjustable. The roller extends across substantially the entire width of the deck. The roller resists scalping and stripes the grass, both of which are aesthetically desirable. Each deck assembly is connected to the frame by a generally L-shaped, horizontally-extending lifting arm operable to lift the deck assembly relative to the frame. Each deck assembly is connected to the frame by its own lifting arm. Each lifting arm has an inner end pivotally connected to the frame. A cross member is mounted on the outer end of the lifting arm for pivotal movement about a generally vertical axis and about a generally horizontal axis extending in the forward-rearward direction. One end of the cross member is connected to one of the deck assembly side plates for pivotal movement about a generally horizontal, laterally-extending axis adjacent the forward ends of the side plates, and the other end of the cross member is connected to the other side plate for pivotal movement about the same axis. This construction enables the lawn mower to cut the undulating terrain of a golf course rough and to be controlled for close trimming. Also, as mentioned above, the lawn mower requires much less maintenance than the reel mowers historically used to cut a golf course rough. Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings. DESCRIPTION OF THE DRAWINGS Fig. 1 is a top plan view of a lawn mower embodying the invention. Fig. 2 is a perspective view of a cutting deck assembly. Fig. 3 is a top plan view of the cutting deck assembly. Fig. 4 is a side elevational view of the cutting deck assembly. Fig. 5 is a rear elevational view of the cutting deck assembly. Fig. 6 is a view taken along line 6--6 in Fig. 3. Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. DESCRIPTION OF THE PREFERRED EMBODIMENT A lawn mower 10 embodying the invention is illustrated in Fig. 1. Except as described below, the lawn mower 10 is identical to a lawn mower disclosed in our European Patent Application No. 97306482.7, filed 26th August, 1997, entitled "PARALLEL-SERIES FOUR-WHEEL-DRIVE HYDRAULIC CIRCUIT FOR A RIDING LAWN MOWER". The lawn mower 10 comprises a frame 12 (partially shown in Figs. 2-5) supported by front wheels 14 and rear wheels 16 for movement over the ground. While the illustrated lawn mower 10 is rear-steering and has four-wheel drive, it should be understood that the invention is applicable to front-steering or two-wheel-drive lawn mowers. The lawn mower 10 further comprises a power source 18 supported by the frame 12. The power source may be any type known in the art, such as a gasoline-powered, internal-combustion engine. The engine drives a hydraulic pump (not shown) that supplies hydraulic fluid to hydraulic motors (not shown) drivingly connected to the wheels 14 and 16. The lawn mower 10 further comprises an operator's seat 20, and a conventional steering system, including a steering wheel 22, enabling the operator to steer the lawn mower 10. In the illustrated construction, the steering system is hydraulic and is connected to the rear wheels 16 to steer the lawn mower 10. The lawn mower 10 further comprises front and rear rows 26 and 30, respectively, of cutting deck assemblies 34. More particularly, in the illustrated construction, the lawn mower 10 has three side-by-side front cutting deck assemblies 34 in front of the front wheels 14, and two rear cutting deck assemblies 34 behind the front wheels 14 and in front of the rear wheels 16. As is known in the art, each rear deck assembly 34 is aligned with the gap between two adjacent front deck assemblies 34. Each of the cutting deck assemblies 34 includes (see Figs. 2-5) a single-spindle mulching deck 38 defining a downwardly opening space 42 (Fig. 4). The deck 38 is located between and supported by a pair of laterally-spaced, generally vertically-extending side plates 46 and 48. The term "lateral" is used herein to mean the direction from one side of the lawn mower to the other, i.e., perpendicular to the forward-rearward direction. Two front wheels 50 rotate about an axle 54 (Figs. 2 and 3) extending between the side plates 46 and 48 in front of the deck 38, such that each front wheel 50 supports one of the side plates 46 and 48 and the deck 38 for movement over the ground. A rear roller 58 extends between the side plates 46 and 48 and also supports the side plates 46 and 48 and the deck 38 for movement over the ground. The roller 58 is behind the deck 38 and extends across substantially the entire width of the deck 38. The roller 58 resists scalping and stripes the grass. The deck 38 is mounted on the side plates 46 and 48 such that the height of the deck 38 relative to the ground is adjustable. In the illustrated construction, the deck 38 includes spaced deck plates 66 and 68 (Figs. 3 and 5) extending upwardly adjacent the side plates 46 and 48, respectively. The upper end of each side plate 46 or 48 has thereon (see Fig. 2) generally horizontal, inwardly-extending ears 69 and 70, with the ear 69 adjacent the front of the side plate and the ear 70 adjacent the rear of the side plate. Fixed to the ears 69 and 70 of each side plate 46 or 48 is an elongated plate member 71 having outwardly-extending ears 72 and 73 respectively secured to the ears 69 and 70 by suitable means such as bolts or screws 74. Each side plate 46 or 48 and the corresponding plate member 71 has therein (see Figs. 4 and 6) a series of holes 76. Each of the deck plates 66 and 68 has therein several vertically-spaced series of holes 78. Bolts 80 extending through holes 76 in the side plates 46 and 48 and in the plate members 71 and through holes 78 in the deck plates 66 and 68 secure the deck 38 to the side plates 46 and 48. The height of the deck 38 is adjusted by changing the holes 78 in the deck plates 66 and 68 and/or the holes in the side plates 46 and 48 and in the plate members 71 through which the bolts 80 extend. A single spindle 84 (Fig. 4) is mounted for rotation about a generally vertical axis within the space 42 defined by the deck 38. The spindle 84 is driven by a hydraulic motor 88 on top of the deck 38. The above-mentioned pump supplies hydraulic fluid to the motor 88. It should be understood that other means could be used to drive the spindle 84. A set of cutting blades is mounted on the spindle 84 for rotation therewith. In the illustrated construction, as shown in Figs. 3 and 4, each blade set includes a lower, leading blade 92 and an upper, trailing blade 96. The leading blade 92 has a leading cutting edge and an upwardly angled trailing edge or lift. Preferably, the lift of the leading blade 92 is angled upwardly at an angle of approximately forty-five degrees. The trailing blade 96 has a leading cutting edge for cutting clippings deflected upwardly by the lift of the leading blade 92. In alternative embodiments of the invention, different blade arrangements can be employed. Each of the deck assemblies 34 is mounted on the frame 12 by a generally L-shaped, horizontally-extending lifting arm 112, such that each deck assembly is mounted on its own lifting arm 112. The lifting arm 112 has (see Figs. 2 and 3) a laterally-extending inner leg 116 with an inner end connected to the frame 12 for pivotal movement about a generally horizontal axis 120 extending in the forward-rearward direction. The arm 112 also has an outer leg 124 extending in the forward-rearward direction. A cross member 128 is mounted on the outer end of the outer leg 124 for pivotal movement about a generally vertical axis 132 and about a generally horizontal axis 136 extending in the forward-rearward direction. Each of the opposite, laterally-spaced ends of the cross member 128 has thereon (see Figs. 2, 3, 5 and 6) a downwardly and slightly rearwardly extending arm 140. The lower end of one arm 140 is connected to the side plate 46 for pivotal movement about a generally horizontal, laterally-extending axis 144 adjacent the forward ends of the side plates 46 and 48. The lower end of the other arm 140 is connected to the side plate 48 for pivotal movement about the axis 144. A hydraulic assembly 148 (partially shown only in Fig. 5) connected between the arm 112 and the frame 12 pivots the arm about the axis 120 for lifting and lowering the deck 38. When the deck is lowered for cutting, the hydraulic assembly allows the lifting arm to "float," thereby allowing the deck 38 to move vertically relative to the frame 12. The connection of the deck 38 to the arm 112 via the cross member 128 allows the deck 38 to pivot relative to the frame 12 about the three mutually perpendicular axes 132, 136 and 144. This mounting arrangement enables the deck 38 to adjust to undulating terrain, thereby substantially avoiding scalping. It should be understood that the lawn mower 10 could have only two or more than three cutting decks in the front row, and only one or more than two cutting decks in the rear row. Also, other arrangements could be used to mount the decks on the frame 12. Various features of the invention are set forth in the following claims.

Claims: A gang-type rotary lawn mower comprising: a frame supported by wheels for movement over the ground; a power source which is mounted on said frame and which drives at least two of said wheels; an operator's seat mounted on said frame; a steering system enabling the operator to steer said lawn mower; at least two side-by-side front rotary cutting deck assemblies mounted on said frame in front of said front wheels, said front deck assemblies defining a gap between adjacent front deck assemblies; and at least one rear rotary cutting deck assembly mounted on said frame behind said front deck assemblies, each rear deck assembly being aligned with a respective gap between adjacent front deck assemblies; each of said front and rear deck assemblies including a single-spindle cutting deck defining a downwardly opening space, a single spindle mounted for rotation about a generally vertical axis within said space, at least one cutting blade mounted on a spindle for rotation therewith and a roller supporting said deck for movement over the ground, said roller extending across substantially the entire width of said deck. The lawn mower of claim 1, wherein the roller of each deck assembly extends across substantially the entire width of the deck assembly. The lawn mower of claim 1, wherein the roller of each deck assembly is located in a rear portion of the deck assembly. The lawn mower of claim 1, wherein the spindle is mounted for rotation about a generally vertical axis. The lawn mower of claim 1, wherein the at least one rear rotary cutting deck assembly is located behind front wheels of said frame. The lawn mower of claim 1, wherein the at least one rear rotary cutter deck assembly is located between front and rear wheels of said frame. The lawn mower of claim 1 wherein each of said front and rear deck assemblies further includes a pair of rotatable wheels. The lawn mower of claim 1, wherein each rotary cutter deck assembly is connected to the frame by a respective lifting arm operable to lift an associated deck assembly relative to the frame, such that each of the deck assemblies is connected by its own lifting arm to the frame. The lawn mower of claim 8, wherein each lifting arm is connected to the frame for pivotal movement about a generally horizontal axis extending in a forward-rearward direction, and is also connected to a corresponding rotary cutter deck assembly. The lawn mower of claim 9, wherein each lifting arm is generally L-shaped and is connected to the frame at one end and to a corresponding rotary cutter deck assembly at another end. The lawn mower of claim 1, wherein each of the front and rear deck assemblies includes a pair of laterally-spaced, generally vertically-extending side plates having forward ends. The lawn mower of claim 11, wherein: each of the front and rear deck assemblies further includes a first front wheel supporting one of the side plates for movement over the ground, and a second front wheel supporting the other of the side plates for movement over the ground; and the rear roller extends between the side plates and supports the side plates for movement over the ground. The lawn mower of claim 11, wherein the deck of each of the front and rear deck assemblies is located between the side plates and in front of the roller and is mounted on the side plates such that the height of the deck relative to the ground is adjustable by changing the position of the deck relative to the side plates. The lawn mower of claim 1, wherein each deck assembly also includes a hydraulic motor which is mounted on the deck and which is drivingly connected to the spindle. The lawn mower of claim 1, wherein each deck assembly includes a set of cutting blades mounted on the spindle for rotation therewith, the set of blades including a lower, leading blade having a leading cutting edge and an upwardly angled trailing edge, and an upper, trailing blade having a leading cutting edge for cutting clippings deflected upwardly by the upwardly angled trailing edge of the leading blade, the trailing blade extending at a non-perpendicular angle relative to the leading blade so that clippings coming off the trailing edge of the leading blade are cut immediately by the trailing blade before the clippings start swirling around within the space. The lawn mower of claim 11, wherein each deck assembly is connected to the frame in part by a cross member connected to the frame for pivotal movement about a generally vertical axis and about a generally horizontal axis extending in a forward-rearward direction, the cross member having opposite, laterally-spaced ends, one of the cross member ends being connected to one of the side plates of the associated deck assembly for pivotal movement about a generally horizontal, laterally-extending axis adjacent the forward ends of the side plates, and the other of the cross member ends being connected to the other of the side plates of the associated deck assembly for pivotal movement about the generally horizontal, laterally-extending axis. The lawn mower of claim 16, wherein the ends of the cross member have thereon respective downwardly extending arms, the arms having respective lower ends, the lower end of one of the arms being connected to one of the side plates for pivotal movement about the generally horizontal, laterally-extending axis, and the lower end of the other of the arms being connected to the other of the side plates for pivotal movement about the generally horizontal, laterally-extending axis. A cutting deck assembly for a gang-type rotary lawn mower having a frame, the cutting deck assembly comprising: a single-spindle cutting deck defining a downwardly opening space; a single spindle mounted for rotation about a generally vertical axis within said space, at least one cutting blade mounted on a spindle for rotation therewith about a substantially vertical axis; a pair of laterally-spaced, generally vertically extending side plates having forward ends; a first front wheel supporting one of said side plates for movement over the ground; a second front wheel supporting the other of said side plates for movement over the ground; a roller extending between said side plates supporting said side plates for movement over the ground, wherein said deck is coupled to said side plates and located in front of said roller such that the height of said deck relative to the ground is adjustable by changing the position of said deck relative to said side plates; and a lifting arm adapted to pivotally interconnect said cutting deck assembly and the frame. The cutting deck assembly of claim 18, wherein the roller extends across substantially the entire width of the deck. The cutting deck assembly of claim 18, wherein the roller is located in a rear portion of the deck. The cutting deck assembly of claim 18, further comprising a pair of rotatable wheels for support of the cutting deck assembly over the ground. The cutting deck assembly of claim 18, further comprising a hydraulic motor is mounted on the deck and which is drivingly connected to the spindle. The cutting deck assembly of claim 18, further comprising a set of cutting blades mounted on the spindle for rotation therewith, the set of blades including a lower, leading blade having a leading cutting edge and an upwardly angled trailing edge, and an upper, trailing blade having a leading cutting edge for cutting clippings deflected upwardly by the upwardly angled trailing edge of the leading blade, the trailing blade extending at a non-perpendicular angle relative to the leading blade so that clippings coming off the trailing edge of the leading blade are cut immediately by the trailing blade before the clippings start swirling around within the space. The cutting deck assembly of claim 18, further comprising a cross member connectable to the frame for pivotal movement about a generally vertical axis and about a generally horizontal axis extending in a forward-rearward direction, the cross member having opposite, laterally-spaced ends, one of the cross member ends being connected to one of the side plates for pivotal movement about a generally horizontal, laterally-extending axis adjacent the forward ends of the side plates, and the other of the cross member ends being connected to the other of the side plates for pivotal movement about the generally horizontal, laterally-extending axis. The cutting deck assembly of claim 24, wherein the ends of the cross member have thereon respective downwardly extending arms, the arms having respective lower ends, the lower end of one of the arms being connected to one of the side plates for pivotal movement about the generally horizontal, laterally-extending axis, and the lower end of the other of the arms being connected to the other of the side plates for pivotal movement about the generally horizontal, laterally-extending axis.

Inventors: BEDNAR RICHARD D, BEDNAR, RICHARD D.
Applicants: RANSOMES AMERICA CORP, RANSOMES AMERICA CORPORATION
Application year: 1998
Main classification: A01D75
IPC codes: A01D34, A01D75