Abstract:
A system adjusts the height-of-cut of a cutting reel unit. The system includes a cutting reel; a first frame supported on at least one support element that is supported on, and is movable along, the ground; and a second frame supporting the cutting reel. The system further includes an actuator that has a first portion connected to the first frame and a second portion connected to the second frame, wherein a distance between the first and second portions is adjustable. The actuator includes a motive mechanism that is activated to adjust the distance. The system can include at least one strut pivotally connected to the first frame and pivotally connected to the second frame on a second side of the second frame opposite to the first side. The strut extends between the first frame and the second frame. The strut defines the rotation of the second frame with respect to the first frame as the relative elevation of the second frame is adjusted with respect to the first frame.

Description:
TECHNICAL FIELD OF THE INVENTION 
   The invention relates to cutting reel units for mowers, and particularly mechanisms and methods for adjusting cutting reel units. 
   BACKGROUND OF THE INVENTION 
   Conventional mowing machines have an attached cutting reel unit or multiple units. Such machines typically move the cutting reel unit across the ground adjacent to the machine. Grass beneath the cutting reel unit is mowed as the machine travels forward. Conventional reel mower vehicles can include a plurality of arm members that extend from the vehicle, each arm having a cutting reel unit attached to its outer end portion. 
   The cutting reel units typically include front and rear skids or rollers that support or carry the cutting unit across the surface of the ground during mowing operation. Such vehicles and cutting reel units are disclosed for example in U.S. Pat. Nos. 5,343,680; 5,412,931 and 5,459,984. 
   Conventional cutting reel units provide a plurality of blades coupled together to form a generally cylindrical reel that rotates about a transverse axis. The blades pass in close proximity to a bedknife to create a scissoring action for cutting vegetation such as grass. A frame typically houses the reel and bedknife. Wheels, rollers or skids are coupled to the frame for engaging or rolling across the ground to operatively support the reel and bedknife at a predetermined height above the ground. The height at which grass is cut is therefore determined by the height at which the wheels, rollers or skids carry a frame, reel and bedknife above the ground. Cutting reel units are typically used for mowing golf courses or other areas were a relatively low and accurate cut is desirable. 
   To produce a high quality cut, and a cut that is even for multiple cutting reel units and across mowing passes by a machine with multiple cutting reel units, it is necessary that the height-of-cut on each cutting reel unit be properly adjusted. It is known that reel mowers have an adjustment mechanism for adjusting the reel mowing height. One type of height adjustment mechanism utilizes a plurality of vertically aligned holes for a cutting unit frame. The rollers are coupled to a mounting member or plate that includes an opening. The mounting plate is coupled to the frame by insertion of a pin through both the mounting plate opening and one of the holes defined by the cutting unit frame. The cutting height can be varied by inserting the pin through a different hole in the frame. Other types of height adjustment mechanisms utilize threaded bolts which set the adjustment height using nuts engaged on the bolts and positionable to support a portion of the frame such that the cutting reel unit is held securely in the desired vertical position with respect to the rollers. A wrench is used to adjust the nuts to positions on the bolts to thereby adjust the cutting height. 
   Another type of cutting reel unit utilizes a slotted mounting arm that is coupled with the rollers. A bolt received by the slot is used to adjust the height by loosening the bolt and shifting the slide-mounting arm to a new position. 
   For all height-of-cut adjustments, there is a generally accepted and common method for determining a cutting reel unit&#39;s existing height-of-cut and how far it needs to be adjusted towards a targeted adjustment. The procedure for setting the cutting height typically involves fastening a gauge bar to the bedknife such that the upper surface of the bar is parallel to a forward, horizontal position of the bedknife and at the desired distance below the cutting edge of the bedknife. The front and rear rollers are then adjusted to come into contact with the upper surface of the gauge bar. 
   The adjustment relationship between the front and rear rollers—relative to the cutting reel itself—is often termed the ‘angle of attack’ for the bedknife. This relationship refers to the relative pitch (front to back) or angle of the bedknife in relation to the ground surface. The angle of bedknife attack is an important parameter which affects the cut quality and effectiveness. Varying the height-of-cut must take the angle of attack into consideration. 
   Reel adjustments are checked regularly and adjustments are conducted as a preventative measure to ensure optimum cut quality, as a reactive measure when poor cut quality is detected, and when reel damage occurs. Reel adjustments are also necessary when a cutting reel unit is “re-tasked,” in effect, adjusted for cutting another type of grass or grass to be cut to a different height. For example, a cutting reel unit could be re-tasked from an adjustment appropriate for a golf course fairway to adjustment appropriate for a golf course green, the two areas having different grass height requirements. However, re-tasking a cutting reel unit is time-consuming. To avoid re-tasking cutting reel unit, many golf courses have cutting reel units or cutting machines which remain designated or set for a particular grass or area requirement, in effect, a designated group of cutting units for different areas of the golf course. This technique necessitates multiple cutting units or cutting machines. Multiple cutting units or machines can result in higher capital costs and maintenance costs. 
   The present inventors have recognized that proper mower adjustments are often hard to achieve through manual adjustment methods. 
   The present inventors have recognized that the reel height-of-cut adjustment is an adjustment that needs to be adjusted accurately and precisely, but is also difficult to adjust on individual mowing reels. 
   The present inventors have recognized that the accuracy and precision of these adjustments can be improved through automated adjustments. The present inventors have recognized that a need exists for dynamic adjustment and capability for multi-area mowers or mowers that are capable of mowing multiple areas. 
   The present inventors recognize the need exists to be able to re-task a cutting reel unit or units dynamically to allow a single machine to mow multiple area types with different cutting reel unit setup requirements. 
   The present inventors have recognized the need to improve the adjustment process to ensure a shorter required time, ease of adjustment, and improved reel operation quality. 
   The present inventors have recognized that the ease, speed, accuracy and precision of adjusting the height-of-cut of a reel cutting unit can be improved through automated adjustment. 
   SUMMARY OF THE INVENTION 
   The invention provides a system for adjusting height-of-cut of the reel of a cutting reel unit. The cutting reel unit can be carried by, or attached to, a vehicle, such as a tractor, singularly or as one of a plurality of cutting reel units, or can be incorporated into a riding mower, a walking mower or a ride-on mower, also singularly or as one of a plurality of cutting reel units. 
   The system includes a cutting reel; a first frame supported on at least one support element that is supported on, and is movable along, the ground; and a second frame supporting the cutting reel. The cutting reel can be one driven in rotation by one or more hydraulic motors, electric motors, by the traction drive of the mower machine or vehicle, or by other type drive. 
   The system further includes an actuator that has a first portion connected to the first frame and a second portion connected to the second frame, wherein a distance between the first and second portions is adjustable. The actuator includes a motive mechanism that is activated to adjust the distance. 
   The motive mechanism is preferably a stepper motor and a lead screw mechanism driven to extend or retract by the stepper motor and the motor and lead screw operatively connected to the first and second portions. 
   Preferably, the actuator is one of two actuators, one actuator located at each end of the reel, and the actuators each having a first portion connected to the first frame and a second portion connected to the second frame, wherein a distance between the first and second portions is adjustable, and including a motive mechanism that is activated to adjust the distance. 
   The system can include a precise position sensor, and a controller, the precise position sensor signal-connected to the controller, the controller signal-connected to the actuator to precisely adjust the distance based on a position signal from the sensor. 
   The sensor can comprise an optical encoder having a read head signal-connected to the controller and an optical disk arranged to rotate with an output shaft of the stepper motor. 
   The system can include at least one strut pivotally connected to the first frame and pivotally connected to the second frame. The strut length between pivotal connections to the first and second frames, defines the slight rotation of the second frame with respect to the first frame to change the “angle of attack,” or approach angle of the reel and bedknife to the blades of grass, to be at an advantageous angle over the range of the height-of-cut adjustment. 
   Preferably, the at least one strut comprises two struts, one of the two struts located on each end of the second frame. Each strut is pivotally connected to the first frame and pivotally connected to the second frame. 
   According to one embodiment, the at least one support element comprises a first roller and a second roller, and the first frame comprises a spaced-apart pair of plate assemblies that are connected together on a rear side by the first roller and connected together on a front side by the second roller. The second frame comprises a spaced-apart pair of mounting plates that are connected together by the cutting reel, the mounting plates located between the plate assemblies. The struts are each pinned to one of the plate assemblies at a rear location thereon and to an adjacent one of the mounting plates at a front location thereon. 
   According to the embodiment, each of the plate assemblies is adjustable in horizontal dimension in order to mount additional accessories, such as a conditioner. An accessory can be a device which contacts or manipulates the grass immediately before it is cut by the reel and bedknife. 
   The disclosed invention provides advantages in that the system allows for rapid and automatic adjustment of the height-of-cut of a reel of a cutting reel unit without operator intervention following initiation of the adjustment. The reel can be adjusted in seconds. The method has speed and consistency advantages over manual adjustment, and does not require detection of poor cut quality in order to perform the automatic adjustment. 
   The system allows a cutting reel unit to be rapidly re-tasked to cut different grass heights for different areas of a golf course. The system allows a single cutting reel unit to be readily usable for multiple golf course areas. 
   By adjusting the height-of-cut automatically, the process may be accomplished more consistently without the presence of a skilled mechanic. Automated adjustment also provides the capability for the support of autonomous equipment. 
   The cutting reel unit control system can be implemented through a variety of control architectures such as distributed control or centralized control. The control protocol can be CAN, serial, or other control protocols. 
   The cutting reel unit height-of-cut adjustment can be automatically self-adjusting, including a control system that periodically corrects the height-of-cut. 
   The cutting reel unit height-of-cut adjustment can include a control system configured as a central controller or by controllers located at each cutting unit, or even by a local controller designated for each actuator. The cutting reel unit height-of-cut adjustment can be adjusted after operator or automatic initiation of an adjustment routine in a central controller or by operator or automatic initiation of control routines performed by controllers at each cutting unit or at each actuator. 
   The cutting reel unit height-of-cut adjustment can be made by a controller external to the cutting unit, such as by a control unit that is used in a shop to re-adjust or re-task a cutting unit for a pre-selected grass condition or area and desired height-of-cut. 
   Alternatively to operator initiation, the cutting reel height-of-cut adjustment can also be initiated by a controller or control units that is/are responsive to a sensor such as a height of grass sensor, or by a location sensor and/or sender on the cutting unit or cutting machine that communicates with an external ground-based system or a global positioning system (GPS). These systems, responsive to external conditions, along with the onboard control systems as described herein facilitate implementation of the height-of-cut adjustment system in either a manned cutting machine or an autonomous cutting machine. 
   For example, different areas of a golf course could be mapped electronically and preprogrammed into an onboard or remote controller and such controller could communicate with the external positioning system and thereafter adjust the actuators to adjust the height-of-cut for the type of grass, the area, and desired cut lines for corresponding areas of the golf course. 
   Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a cutting reel unit according to the invention; 
       FIG. 2  is a bottom perspective view of the cutting reel unit of  FIG. 1 ; 
       FIG. 3  is a fragmentary sectional view taken generally along line  3 — 3  of  FIG. 1 , with portions of the cutting unit removed for clarity of description; 
       FIG. 3A  is a schematic view of a reel position with respect to a bedknife position; 
       FIG. 4  is a sectional view of an actuator as shown in  FIG. 3 ; 
       FIG. 5  is a side view of the cutting unit shown in  FIG. 1  with portions removed for clarity of description wherein the reel is illustrated in an elevated operating position; 
       FIG. 6  is a side view of the unit shown in  FIG. 1  wherein the reel is illustrated in a lowered operating position; 
       FIG. 7  is a fragmentary, partial sectional view taken generally along offset line  7 — 7  of  FIG. 5 ; 
       FIG. 8  is a perspective view of the unit shown in  FIG. 1  with the reel removed for illustrating underlying parts; and 
       FIG. 9  is a schematic diagram of a control system of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIGS. 1 and 2  illustrate a mower cutting reel unit  10  according to the present invention. The mower cutting reel unit  10  is adapted to be pulled alone or within a group of like units by a vehicle such as described in U.S. Pat. Nos. 5,343,680; 5,412,931 or 5,459,984, herein incorporated by reference. A plurality of blades  11  are coupled together to form a generally cylindrical reel  12  which rotates about a transverse axis in close proximity to an edge  14   a  of a bedknife  14  ( FIG. 2 ) for cutting vegetation, such as grass, with a scissoring action. 
   A motor  16 , carried at one side of a frame  18  that generally houses and supports the reel  12 , drives the reel  12 . The motor  16  can be a hydraulic, electric or other type motor. Alternatively, a transmission arrangement between the traction drive of the machine or vehicle and the reel can be used to rotate the reel. A hydraulic motor is indicated in the figures. 
   The inside frame  18  is carried by an outside frame  22 . The outside frame  22  is supported on front and rear rollers  24 ,  26  respectively. The inside frame  18  is supported on the outside frame  22  by actuators  30 ,  32  and by struts  36 ,  36 . The struts  36 ,  36  are substantially mirror-image identical in configuration. A pushing or towing frame  42  is arranged between the inner and outer frames  18 ,  22 . The towing frame  42  includes vertical plates  44 ,  46  fastened to side plates  52 ,  54  of the outer frame  22  by pins  56 ,  58  residing in slots  52   a ,  54   a . The slots  52   a ,  54   a  are part of a mechanism which permits the reel to be pushed from the rear when rolling, and still touch down heel first when lowered. 
   A crossbar  48  connects the side plates  44 ,  46 . A vehicle connector or lift arm can be engaged at a select position along the crossbar  48  to tow or push the cutting unit  10  along the ground during the cutting operation. 
   The outside frame  22  also includes adjustable bracket members  62 ,  62  connected by fasteners  66  to a respective side plate  52 ,  54 . The bracket members  62 ,  62  are substantially mirror-image identical in configuration. The bracket members  62 ,  62  each include a short L-shaped member  62   a  and a horizontal member  62   b . The members  62   a ,  62   b  include a series of holes  68  wherein a registered pair of holes between the members is selectable to set a horizontal overall dimension of the bracket members  62 ,  62  using fasteners through the registered pair of holes. The selectable dimension is useful where additional accessories are to be used, for example a conditioner, or a device that contacts and manipulates the grass immediately before it is cut by the reel and bedknife, could be added to the unit  10  behind the roller  24 . The unit  10  is shown with holes  68  selected to set a maximum horizontal dimension of the bracket members  62 ,  62  such as would be used when a further front roller (not shown) would be installed behind the front roller  24 . With just the front roller  24  used, different holes  68  would preferably be selected to set a minimum horizontal dimension of the bracket members  62 ,  62 . Vertical portions  62   c ,  62   c  of the members  62 ,  62  extend downward to be connected via plates  72 ,  72  to front support assemblies  76 ,  76  that are supported by the front roller  24 . The front support assemblies  76 ,  76  are substantially mirror-image identical in configuration. 
   Plates  84 ,  84  connect the outer frame side plates  52 ,  52  to rear support assemblies  88 ,  88  that are supported by ends of the rear roller  26 . The rear support assemblies  88 ,  88  are substantially mirror-image identical in configuration. 
   The inside frame  18  includes side plates  106 , 106  connected together by crossbars  112 ,  114 . The side plates  106 , 106  are substantially mirror-image identical in configuration. A grass deflector plate  118  is arranged between the bars  112 , 114  above the reel  12 . The side plates each include a front flange  122 . A tube  126  is welded to each of the front flanges  122 . A tube  132  is also welded to each of the members  62   b . Sleeve bearings  140  are fit into each tube and a pin, bolt or other fastener  142  is used to pivotally connect each of the angled struts  36  to a respective pair of tubes  126 ,  132 . 
     FIG. 3  illustrates right side components of the unit  10 . The left side components are configured in substantially the same, but mirror-image manner. The actuators  30 ,  32  each include a motor drive  30   a , a housing  30   b , and an actuator rod  30   c  extending out of a-bottom of the housing  30   b . The rod  30   c  extends or retracts vertically from the housing  30   b  by a selected turning direction of the motor drive  30   a . The housing  30   b  is fastened to the respective side plate  106  by fasteners  143 . The rod  30   c  is pivotally fastened to the outer frame  22 , particularly to the respective outer frame side plate  52  by a fastener or pin  146 . 
   Thus, extension of the rods  30   c  from the housings  30   b , of the actuators  30 ,  32 , lifts the inside frame  18  with respect to the outside frame  22 . Retraction of the rod  30   c  into the housing  30   b , of the actuators  30 ,  32 , lowers the inside frame  18  with respect to the outside frame  22 . 
   The struts  36 ,  36  ( FIGS. 1 and 2 ) prevent excessive forward or rearward tipping of the inside frame  18  lifted or lowered at the rear thereof and ensures a substantially straight vertical lifting or lowering of the inside frame  18 . The geometry of the frames  18 ,  22 , struts  36 ,  36  and actuators  30 ,  32  advantageously slightly tip the reel and bedknife forward with rising height-of-cut. This change in the “angle of attack” results in a more effective cutting. 
     FIG. 3A  illustrates schematically the side plate  106  and a profile outline of the reel  12  wherein the height-of-cut “h” from grade “g” and an offset “x” from the reel centerline “c” are shown. The attack angle “a” is also shown. Effective guideline maximum attack angles “a” with respect to height-of-cut are:
         “h”=6 mm, “a”=0 deg   “h”=20 mm, “a”&lt;1.3 deg   “h”=75 mm, “a”&lt;5 deg
 
The preferred embodiment of the invention satisfies these guidelines.
       
   For the preferred embodiment, the table below sets forth the relative positioning of the profile of the edge  14   a  with respect to the reel centerline “c” as the inside frame  18  is lifted through a range of height-of-cut “h” and tilted over a range on attack angles “a”. 
   
     
       
             
             
             
           
         
             
                 
             
             
               “h” 
               “a” 
               “x” 
             
             
                 
             
           
           
             
               10 mm 
               0.38 deg 
               6.95 mm 
             
             
               15 mm 
               0.81 deg 
               7.38 mm 
             
             
               20 mm 
               1.20 deg 
               7.77 mm 
             
             
               25 mm 
               1.55 deg 
               8.12 mm 
             
             
               30 mm 
               1.86 deg 
               8.43 mm 
             
             
               35 mm 
               2.13 deg 
               8.70 mm 
             
             
               40 mm 
               2.36 deg 
               8.93 mm 
             
             
               45 mm 
               2.56 deg 
               9.13 mm 
             
             
               50 mm 
               2.72 deg 
               9.29 mm 
             
             
               55 mm 
               2.86 deg 
               9.43 mm 
             
             
               60 mm 
               2.95 deg 
               9.52 mm 
             
             
               65 mm 
               3.02 deg 
               9.59 mm 
             
             
               70 mm 
               3.05 deg 
               9.62 mm 
             
             
               75 mm 
               3.06 deg 
               9.63 mm 
             
             
                 
             
           
        
       
     
   
   Actuators  202 ,  204  are provided on a front side of the inside frame  18  adjacent opposite ends of the reel  12 . The actuators  202 ,  204  each include a motor actuator  202   a , a housing  202   b , and an actuator rod  202   c . The housing  202   b  is fastened to the respective side plate  106  by fasteners  212 . The rods  202   c ,  202   c  are fastened to respective reel bearing housings  216 ,  216  that journal the reel  12  at opposite ends of the inside frame  18 . Each rod  202   c  is pinned to a ball joint  220  that is fixed to the respective housing  216 , by an elongated pin  226 . 
   Each reel bearing housing  216  is pinned to a respective side plate  106  by a pin or fastener  230 . The extension or retraction of the rod  202   c  with respect to the housing  202   b , of the actuators  202 ,  204  pivots the reel bearing housing  216  about the pin or fastener  230 . By extending the rod  202   c  and pivoting the reel housings  216 ,  216 , the blades  11  can be brought closer to or further from the bedknife  14  ( FIG. 2 ), particularly, closer to or further from an edge  14   a  of the bedknife  14 . 
   The ball joint  220  is carried on the base pin  231  ( FIG. 7 ). The base pin is fixed to the bearing housing  216  and extends through the bearing housing to slide through a slot  232  formed in the side plate  106 . For each actuator  202 ,  204 , an L-shaped spring  234  is fixed to the rod  202   c  and presses against the ball joint  220  to bias the rod  202   c  in the downward direction, to remove play in the ball joint  220 . 
     FIG. 4  illustrates a typical actuator  30 ,  32  such as the actuator  30 . The actuator  30  includes the motor drive  30   a , the housing  30   b  and the rod  30   c . Inside the housing  30   b  there is a lead screw  260  that is driven into rotation by a stepper motor  266  of the motor drive  30   a . The lead screw  260 , being an extension of a motor shaft  268 , is rotated by the stepper motor  266 . 
   The rod  30   c  is a substantially hollow cylinder and includes a rod end portion  274  fixed to a rod body portion  276  by threaded mutual engagement. The lead screw  260  extends substantially through the body portion  276 . A lead nut  280  is fixed to the rod body portion  276 . The lead nut  280  can include an outer metal casing  282 , such as brass, and an inner sleeve  284 , such as plastic, having internal Acme threads engaged to corresponding external Acme threads on the lead screw  260 . The lead screw  260  can be stainless steel. Alternatively, the lead nut could be formed as a unitary part with the rod body portion  276 , such as both being formed of plastic or metal. 
   The motor drive  30   a  includes windings  307 , bearings  308 , and an optical encoder  310 . The encoder  310  includes a target  312  and a read head  314 . The read head  314  includes two spaced-apart light emitting and reading devices, used to determine position of the rotating target disk and also its direction of rotation. To set absolute position of the rod, the rod can be extended or retracted by the stepper motor  266  to maximum or minimum extension, until the motor  266  stalls. At this position, the encoder will send no more pulses to the controller since the target disk stops rotating. This sets the maximum or minimum extension. The stepper motor  266  can then be reversed and selectively driven a pre-selected amount to properly position the rod end portion  274 . 
   The actuators  202 ,  204  can be similarly configured as the actuators  30 ,  32  except provision for eliminating backlash is preferred for these actuators  202 ,  204  given the more fine accuracy of position required for reel-to-bedknife clearance adjustment. Such provision is disclosed in U.S. Ser. No. 10/427,720, identified by attorney docket number 6270P0300US filed on the same day as the present application and herein incorporated by reference. 
     FIGS. 5 through 8  illustrate further views of the unit  10  with different components removed for clarity of description.  FIG. 5  illustrates the inside frame  18  in a low position with respect to the outside frame  22 .  FIG. 6  illustrates the inside frame  18  in a raised position with respect to the outside frame  22 . 
     FIG. 9  illustrates a controller  300 , such as a microprocessor, used to control the actuators  30 ,  32 . An operator input station  306  such as a keypad is provided for giving instructions to the controller  300 . 
   The operator, via the input station  306 , or the controller responsive to an automatic routine, can command adjustment of the height-of-cut, by inputting a height-of-cut dimension, such as in mm. The actuators  30 ,  32  can be adjusted individually to set a desired lateral degree of the height-of-cut level, such as to ensure a level cut. A position signal S 1  from each actuator read head  314  is communicated to the controller  300 , and an appropriate drive signal S 2  is sent to the stepper motor  266  of each actuator via appropriate signal conditioning and/or amplification to position rod end portions  274  with respect to the respective actuator body  30   b  of the actuators  30 ,  32 . 
   The adjustments of the invention can all be automatically accomplished at the direction of the controller after initiation by an operator. Although the adjustments as set forth above are described as being operator initiated, the adjustments can also be initiated automatically during operation, or initiated periodically by the controller, or initiated by a change in reel tasking, i.e., a new type of grass or length of grass to be cut. This change in reel tasking can be initiated by a sensed signal or a remote signal such as from a grass height sensor  400 , or from a signal from a ground-based system  404  or a GPS based position system  406 . 
   From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.