Abstract:
An apparatus, systems and methods for automatically disengaging and re-engaging a cutting implement on a mowing machine by disconnecting and connecting, respectively, electrical power to an implement drive means. Power to the implement drive means is disconnected or connected according to gear positions of transmission control levers provided on the mowing machine. At designated gear positions, cut-out switches associated with the implement drive means are effective to interrupt power to the implement drive means. Repositioning the control levers to non-designated gear positions restores power to the implement drive means. The automatic disengagement/re-engagement of the cutting implement based on the gear position of transmission control levers may be used for two lever zero-turn-ride-on mowing machines or more traditional single lever ride-on mowing machines.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority filing benefit of International PCT application PCT/US2003/040723 filed Dec. 19, 2003, and published under PCT 21(2) in the English language; and U.S. Provisional Patent Application Ser. No. 60/434,893 filed Dec. 19, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention relates to lawn/turf mowing machines, and more particularly to an implement governing mechanism and method for such machines. 
   2. Description of Related Art 
   Lawn/turf mowing machines are well-known. Such machines commonly have a separably operable engine and cutting deck mounted on a chassis. A gear shift lever, positioned in either forward gear or a reverse gear by the operator, controls the direction of travel of the mowing machine. 
   Industry has recognized the safety concerns posed by mowing machines having cutting blades engaged when the mowing machines travel in a reverse direction. For example, U.S. Pat. No. 3,984,867 provides a mechanical interlock preventing cutting in reverse. U.S. Pat. No. 3,999,643 discloses a mower having a transmission lever that, in the reverse position, opens a switch to disengage an electric clutch operatively associated with the cutting blade. Newly proposed 2003/2004 ANSI Safety Standard requires a No Mow In Reverse (NMIR) feature on mowing machines. U.S. Pat. No. 6,026,634 also discloses disengagement of the cutting blades when a zero turn radius (ZTR) mowing machine is in full reverse gear. 
   Current technology for precluding the engagement of cutting blades for self-propelled and ride-on machines includes:
     a. A mechanical means that blocks reverse drive of the mowing machine when cutting blades are engaged.   b. An electronic means that blocks reverse drive of the mowing machine when cutting blades are engaged.   c. An electronic means that automatically disconnects power to the cutting blades when the mowing machine&#39;s directional control is changed into Reverse. These systems are usually equipped with a “latching relay” that requires the system to be reset to re-engage the cutting blades in machine “Neutral” or “Forward” travel directions.   d. A mechanical means that disconnects power to the cutting blades when the mowing machine&#39;s directional control is changed to Reverse and requires the system to be reset to re-engage the cutting blades when the machine direction control is returned to Neutral or Forward travel directions.   

   In a and b above, shifting into reverse is prevented, whereas in c and d above, use of the cutting blades is prevented until the system is reset. In order to satisfy the above safety concerns about cutting in reverse while still allowing for optimal operator convenience, it is desirable to provide a lawn/turf mowing machine in which the cutting blades are automatically disengaged in reverse and then automatically re-engaged solely by shifting the mowing machine into an appropriate gear position. 
   SUMMARY OF THE INVENTION 
   Various exemplary embodiments of the apparatus, systems, and methods according to the present invention provide for the automatic disconnection or connection of power to an implement drive means, for example an electrical blade clutch, of a mowing machine. Power to the implement drive means can be automatically disconnected or connected solely by the respective positioning of the mowing machine&#39;s transmission control levers. The present system does not require the machine operator to activate a separate reset switch in order to disconnect or reconnect power to the implement drive means. In all of the various embodiments of the invention, the engine of the mowing machine continues to run regardless of the operational state of the implement drive means. 
   In one aspect of the present invention, the mowing machine comprises a pair of transmission control levers which selectively control the position of a corresponding pair of parallel connected cut-out switches. The parallel connected cut-out switches in turn control the flow of current to the implement drive means. According to this particular embodiment, at least one of the parallel switches must be closed in order to connect power to the implement drive means; that is, at least one of the transmission control levers must be positioned in forward or neutral gear. 
   In other embodiments of the invention, for example, where a single transmission control lever is provided on the mowing machine, a single cutout switch is used to control the flow of current to the implement drive means. In this alternative embodiment, the single cut-out switch must be closed in order to connect power to the implement drive means; that is, the single transmission control lever must be shifted out of reverse. However, in any of the exemplary embodiments of the present invention disclosed herein, the power to the implement drive means can be controlled solely by the respective positioning of the transmission control lever(s). 
   Automatic disengagement and subsequent reengagement of the cutting implement means is suitable for a variety of mowing machines including, but not limited to, zero turn ride on (ZTR) machines having two transmission control levers, or for more traditional ride-on mowing machines having a single transmission control lever. Such automatic disengagement and reengagement of the implement drive means based on the positioning of the transmission control levers provides increased operator convenience and complies with the proposed safety standards. 
   These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various exemplary embodiments of the systems and methods of this invention will be described in detail with reference to the following figures, wherein: 
       FIG. 1  illustrates an exemplary embodiment of a two-control lever ZTR mowing machine according to the invention; 
       FIG. 2  illustrates an exploded view of various transmission control lever components of the exemplary ZTR of  FIG. 1 ; 
       FIG. 3  illustrates an exemplary disengagement/re-engagement device according to the invention; 
       FIG. 4  illustrates an exemplary circuit diagram of the ZTR system of  FIGS. 1-3 ; 
       FIG. 5  illustrates an exemplary ZTR transmission control lever in a neutral gear position; and 
       FIG. 6  illustrates an exemplary ZTR transmission control lever in a reverse gear position. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     FIG. 1  shows an exemplary two-control lever ZTR mowing machine  1  according to one embodiment of the invention. The ZTR mowing machine  1  is comprised of a frame  10  supporting an operator seat  11 , an engine  12  to the rear of the operator seat, and a foot platform  13  to the front of the operator seat. Right and left drive wheels  14 ,  15  are provided to the rear of the mowing machine  1 . Right and left driven wheels  16 ,  17  are provided to the front of the mowing machine. A grass cutting unit  18  is provided under the foot platform  13 . The grass cutting unit  18  includes a cutting implement  20 , such as cutting blades, attached to a spindle axle  22 . An implement drive means  24  ( FIG. 4 ), such as an electric blade clutch, for example, drives the spindle axle  22  to engage the blades  20 . A controllable accessory power take off drive (PTO) is electrically coupled to the electric blade clutch via a PTO switch  111 . The PTO switch has “ON” and “OFF” positions. When the PTO switch is in an “ON” position, the PTO may be connected with the electric blade clutch to engage the cutting blades, and when the PTO switch is in the “OFF” position, the PTO is not connected to the electric blade clutch and the cutting blades are not engaged. Cut-out switches  60  determine whether the PTO is connected or disconnected with the electric blade clutch when the PTO switch is in the “ON” position. 
   A transmission system  30  comprises right and left speed/directional control levers  32 ,  34  that are manually shiftable by an operator between forward, neutral and reverse gear positions. The control levers are pivotably mounted to the foot platform  13 , or frame  10 , on either side of the operator&#39;s seat  11 , for example. Each of the right and left control levers  32 ,  34  are associated with a corresponding right and left drive transaxle  70 . Each transaxle  70  governs the speed and direction of rotation of the corresponding right and left drive wheels  14 ,  15  based on the gear position of each control lever  32 ,  34 . The control levers  32 ,  34  are independently operable whereby positioning both control levers into a forward gear position towards a front F of the mowing machine causes the mowing machine to travel in a generally straight and forward direction, whereas positioning both control levers into a reverse gear position towards the rear R of the mowing machine causes the mowing machine to travel in a generally straight and reverse direction. Positioning one of the control levers into a forward or reverse gear position and positioning of the other of the control levers into one of a neutral or opposite gear position causes turning of the mowing machine. 
     FIG. 2  shows, more specifically, various components associated with each of the control levers  32 ,  34 . A plate  31  connects each of the control levers to the mowing machine. Each plate  31  is mounted to a bracket  37  which is in turn connected to a pivot weldment  36 . Each pivot weldment  36  is connected to a pivot shaft  38 . The pivot shafts  38  are then each connected to linkages  40 ,  41 ,  42 . A universal coupling  43  coordinates the interface of the various linkages  40 ,  41 ,  42  with one another. Each linkage  42  also connects to a respective drive transaxle  70  to translate power to an associated one of the right and left drive wheels  14 ,  15  of the mowing machine  1  via conventional means according to the selected gear position. For example, the linkage  42  associated with the right control lever  32  is connected with the drive transaxle  70  that drives the right drive wheel  14 , whereas the linkage  42  associated with the left side control lever  34  is connected with the drive transaxle  70  that drives the left drive wheel  15 . The connections between the various components described herein may be by combinations of nuts, bolts, and washers as generally shown, or by other known or later developed connection structures suitable to accommodate the necessary motions to the linkages  40 ,  41 ,  42  or other components required in this system. 
     FIG. 3  shows an exemplary two-position, normally closed cut-out switch  60  according to the invention. Each cut-out switch  60  includes a plunger  61 , a leaf spring  62 , a mounting bracket  63 , and an electrical coupler  64 . Depression of the plungers  61  by biasing contact of the control levers with the leaf springs  62  renders the cut-out switches  60  open, whereas extension of the plungers by non-biasing contact of the leaf springs  62  with the control levers returns the cut-out switches  60  to their normally closed state. The position of the control levers  32 ,  34  thus controls the speed/direction of the mowing machine and the open or closed state of the cut-out switches  60 . 
   Referring to  FIGS. 1-3 , right and left cut-out switches  60  are mounted, via brackets  63 , to right and left sides of the mowing machine. Each cut-out switch is mounted within contacting range of a corresponding one of the control levers  32 ,  34  such that sufficient contact by one of the control levers biases a corresponding leaf spring to depress a plunger. The cut-out switches  60  are mounted such that the leaf springs  62  are in biasing contact with the plungers  61  so that the plungers are depressed when a corresponding control lever is shifted into at least the reverse gear position. When the plungers  61  are not in biasing contact with a control lever, the plungers extend. Depression of the plungers corresponds to the open state of the cut-out switches, whereas extension of the plungers corresponds to the closed state of the cut-out switches. 
   In a particularly preferred embodiment of the invention, referring still to  FIGS. 1-3 , each cut-out switch  60  is mounted to the frame  10  of the mowing machine below the operator&#39;s seat  11  and to the front of the control levers  32 ,  34 . At a bottom of each control lever, a pivot weldment  36  is provided with a roller  50 . As the control levers are shifted into a reverse gear position, for example, the roller  50  biasingly contacts, or attaches, to the leaf springs  62  of the cut-out switches  60 . When so contacted, each leaf spring  62  depresses the plungers  61  rendering the cut-out switches  60  open. As a result, the connection between the electric blade clutch  24  and the PTO is broken and power to the electronic blade clutch  24  is interrupted. When power to the electric blade clutch  24  is interrupted, the cutting blades  20  are automatically disengaged. Repositioning at least one of the control levers  32 ,  34  into one of the neutral or forward gear positions, for example, results in the respective plunger  61  extending, thereby closing the cut-out switch  60  and completing the connection between the electric blade clutch and the PTO. Therefore, extending the plunger of at least one cut-out switch effectively provides power to the electric blade clutch  24  and automatically re-engages the cutting blades  20 . 
   According to various other embodiments of the invention, as the artisan should appreciate, the cut-out switches  60  may be mounted at a variety of locations on the mowing machine and still be within biasing contact range of the control levers such that the cutting blades are automatically disengaged whenever the control levers are in the reverse gear position. The exemplary embodiment shown in  FIG. 1  shows the cut-out switches  60  mounted to the frame  10  in front of the control levers  32 ,  34  on either side of the mowing machine. The artisan should readily appreciate that the cut-out switches  60  could as well be mounted to the frame  10  to the rear of the control levers, or to the foot platform  13  to the front or rear of the control levers provided the cut-out switches are within biasing contact range of the levers  32 ,  34  when the control levers are in a reverse gear position. 
   Referring now to  FIG. 4 , there is shown a detailed electric control circuit  100  for the mowing machine  1 . The electric control circuit includes a two-position PTO switch  111  having a ganged movable contact arrangement  111 A-G,  111 B-E, and  111 C-F. Each ganged movable contact arrangement is simultaneously movable between the respective OFF and ON positions. When the PTO switch  111  is in the OFF position (as shown), movable contact arrangement  111 A-G is closed, while movable contact arrangements  111 B-E and  111 C-F are open. When the PTO switch is in the ON position, movable contact arrangement  111 A-G is open, while movable contact arrangements  111 B-E and  111 C-F are closed. 
   Movable PTO contact terminal  111 A is connected to solenoid  118  via movable contact arrangement  103 E-C of brake switch  103 . Fixed PTO contact terminal  111 G is connected to normally closed terminals  105 A,  113 A of transmission switches  105 ,  113  (shown in neutral) and starter terminal  112 S of key switch  112 . In operation, if the PTO switch  111  is OFF (as shown), a complete connection is made between starter terminal  112 S and solenoid  118 , so long as certain conditions are satisfied. Those conditions are satisfied when brake switch terminal  103 E-C is closed, seat switch  106  is open (seat occupied), and transmission switches  105 ,  113  are in neutral (as shown). Under these conditions, if the operator turns key switch  112  to the START position, contact is made between battery terminal  112 B, starter terminal  112 S, and lights terminal  112 L. This permits current from battery  114  to energize the solenoid  118  and activate the starter  119 , thereby starting the engine. 
   Once the engine is started, key switch  112  automatically moves from the START to RUN position. When the key switch moves to the RUN position, connection is made between battery terminal  112 B, regulator terminal  112 R, and lights terminal  112 L. Accordingly, connection between battery  14  and regulator terminal  112 R permits the regulation of gas and fuel to the engine and the engine will continue to run. If the operator leaves the seat while the engine is running, seat switch  106  returns to its normally closed position, allowing current (via inter-harness connector  122 ) to activate second relay  109  and third relay  110 , thereby providing a ground path (via non-activated first relay  108 ) for magneto  115 . Accordingly, the engine will stop running. 
   The electric control circuit  100  further includes parallel connected cut out switches  60 . The cut-out switches are connected in series/parallel; that is, the cut-out switches are connected in parallel with each other and connected in series between the electric blade clutch  24  and PTO contact terminal  111 F. When the PTO switch  111  is ON, movable contact terminals  111 B and  111 C are closed to engage their respective fixed contacts  111 E and  111 F, while movable contact  111 A is opened from its respective fixed contact  111 G. In operation, assuming brake switch  103  is OFF (as shown) and PTO switch  111  is ON, a complete circuit is provided between the charging unit  116 , battery  114  and electric blade clutch  24  via closed PTO contact arrangement  111 F-C, thereby energizing the electric blade clutch  24  and engaging the cutting blades  20 . If one of the cut-out switches  60  is open, as by depression of its plunger  61 , and the other parallel cut-off switch remains closed, a closed current path is still provided to the electric clutch blade  24  via the remaining closed parallel circuit branch so that current continues to energize electric blade clutch  24 , thereby allowing the cutting blades  20  to remain engaged. On the other hand, if both of the cut-out switches  60  are open, as by depression of both of their plungers  61 , the current path in both parallel branches between PTO terminal  111 F and electric blade clutch  24  is interrupted, thereby de-activating the electric blade clutch and disengaging the cutting blades. Accordingly, when in a “full” reverse position with both of the plungers depressed, the cutting blade is not engaged by the electric switch. Once one of the plungers is extended (i.e., not depressed), the electric blade clutch is again activated, connecting the drive system to the cutting blade(s). 
     FIG. 5  illustrates an example of one of the control levers in a neutral gear position whereby the leaf spring  62  associated with cut-out switch  60  is not contacted, and the plunger  61  is not depressed. Conversely,  FIG. 6  illustrates an example of a control lever in a reverse gear position whereby the roller  50  is in biasing contact, or attaches, to the leaf spring  62 , thereby depressing the plunger  61  of the cut-out switch  60 . 
   In operation, assuming the transmission is in neutral, brake switch  103 E-C is closed, and the operator seat is occupied, the mowing machine is started by turning the key switch  112  to the START position. Once the mowing machine is started, the key switch  112  automatically moves to the RUN position. Once the mowing machine is running, the cutting blades can be engaged by turning the PTO switch to the “ON” position. When the PTO switch is in the “ON” position, electrical connection between the PTO and the electric blade clutch is achieved so that the electric blade clutch drives the cutting blades. The operator then positions each of the transmission control levers to a desired forward, neutral or reverse gear position. The cutting blades remain engaged so long as at least one of the transmission control levers is in a neutral or forward gear position. When both of the transmission control levers are in the reverse gear position, i.e., in “full” reverse, the bottom portion of each control lever depresses the plunger of a corresponding one of the cut-out switches. As a result, the PTO is electrically disconnected from the electric blade clutch and the cutting blades are disengaged. Positioning either, or both, of the control levers to a non-reverse, i.e., neutral or forward, gear position causes a corresponding cut-out switch plunger to extend. Accordingly, extension of one, or both, cut-out switch plungers electrically re-connects the PTO with the electric blade clutch and automatically re-engages the cutting blades. 
   The systems and methods described herein thus incorporate a minimal number of components arranged to automatically disconnect and connect power to the electric blade clutch that drives the cutting blades. Automatic disengagement and re-engagement of the cutting blades is achieved as a result. Further, positioning of each of the control levers by rotary motion, as opposed to linear motion, to directly activate or de-activate a plunger of the various cut-out switches permits the cut-out switches to be mounted at a variety of positions. Further, the direct activation of the cut-out switches by the rotary motion of the transmission control levers increases the range whereat automatic disengagement and re-engagement of the cutting blades will occur, and minimizes variations that might otherwise occur due to mis-alignment of parts. 
   While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.