Abstract:
A greensmower having a cutting reel and a traction member and an independent electric circuit and motor for driving each. A handle is attached to the reel for mower guidance by an operator in a walk-behind position. Separate electric controls are connected to each motor for separate speeds for each motor and thereby control the clip rate of the mowing. There are low battery power read-outs and automatic shutoffs. Provision is made for traction powering of the mower even when the reel motor is not operating because of low battery power. A lift-out battery pack is shiftably mounted on the mower for producing the desired force of the mower on the ground.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of U.S. patent application Ser. No. 09/696,700 filed on Oct. 26, 2000. The disclosure of the above application is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to a battery-powered walk-behind greensmower, and more particularly, it relates to a greensmower arranged to control the grass clip-rate and to provide a battery pack and support therefore.  
         BACKGROUND OF THE INVENTION  
         [0003]    The prior mower art is aware of greensmowers useful in mowing golf course greens which require exacting mowing results to assure that the grass is even in its cut throughout the extent across the green. Some of those mowers are walk-behind mowers and some are riding mowers. Of course the riders are inherently heavier than the walk-behind and they therefore tend to create undesirable impressions in the green, and they have other disadvantages.  
         SUMMARY OF THE INVENTION  
         [0004]    Greensmowers generally employ a reel-type mower, and some of them are concerned about the clip-rate of the mowing, and that determines the quality of the mowed grass. The term clip-rate means the distance between the locations of the individual sequential grass cuts produced by the rotating cutting blades successively moving over the grass. The grass between the locations of the cuts will necessarily be left taller than the cut grass at the cut locations. So the cut rate is vital to producing an optimum condition of the grass on the golf course green.  
           [0005]    It is also important that the greensmower be quiet in operation and light in weight and that it permit the operator to see the results of the mowing while the grass is being mowed. Further, the ultimate greensmower will be a walk-behind mower which is battery powered and has electrical circuitry which preludes mower overloads and consequent mower damage; gives the operator current information on the quantity of the battery charge; automatically and manually shuts off under both desirable and undesirable conditions; automatically shuts off the electric power by a predetermined time after the mower has been used for mowing; has both operator-presence handle-located control and electric switch control for the mower power; the motors for the mower and the traction drive automatically stop upon sensing a predetermined heat level within them; and there is the ability to adjust the pressure exerted on the ground by the reel mower roller.  
           [0006]    It is an object of this invention to provide a mower and a method which achieve the aforementioned desirable results. Some of the features that produce those results include the fact that the mower is battery-powered for convenience and quiet operation on the golf course; there is a walk-behind mower for light weight and maneuverability on the greens; there is a greens roller for desired rolling of the green in conjunction with the mowing; there is a counterbalancing of the mower in its end-to-end dimension; there is an adjustable support for the battery so that its weight can be desirably applied relative to the ground rollers of the reel mower itself; and there is a battery box containing a plurality of batteries for providing optimum electric power and for lifting the box with the batteries for servicing, such as replacing and charging.  
           [0007]    Particularly, this invention provides the apparatus and method for establishing the selectable clip-rate desirable for the green being mowed. In achieving this objective, the operator does not need to adjust nor control more than only one variable, namely only the mower ground speed. However, in another embodiment, both the traction speed and the reel speed are controllable by the operator at the handle location and during cutting operation.  
           [0008]    This invention also provides for the arrangement of the support of the battery, actually in a pack of several batteries disposed in a box, and having the box selectively movable relative to the remainder of the mower and thereby control the pressure the mower rollers exert on the ground. In this arrangement, skilled greensmower operators can arrange for their own selectable ground pressure, and they can make their selections at the mowing sites.  
           [0009]    This invention also provides the apparatus and method to both manually and automatically control the electric power in driving both the traction member and the cutting reel. Therefore, there is an avoidance of overload on the mower. Also, there is an electric signal which indicates the level of electric power available for powering the mower, so the operator can then respond accordingly, such as by changing or charging the battery even before the battery is dead.  
           [0010]    Also, there is an electrical control system that will shut down the power to the reel motor when the battery voltage drops below a predetermined level of voltage. Even before that, there is an electric signal that indicates to the operator that the battery power is low. However, the system will still allow the use of the traction drive, so the operator can then transport the mower to a desired parking destination, but the operator will not be able to cut grass to a time when the battery is completely discharged and thereby damaged. This feature prevents abusive deep discharge of the battery, thereby avoiding harm to the battery.  
           [0011]    The electrical system employed herein includes provision for a manual main switch control for the entire system, and it includes a manual switch for the reel motor which can be driven at a constant speed. There is an electrical variable resistor, such as a potentiometer, connected with the traction motor, and the resistor is controllable by the operator at the mower handle location, so the operator has the selectivity of the desired ground speed for the mower and for his walking speed. With the reel switch, the power to the reel can be shut off and the system can be operated under traction drive only, and thereby the system can be used only as a lawn roller.  
           [0012]    In the event of overload on either the traction motor or the reel motor, those motors will automatically shut down. This feature is achieved by a sensor that senses a predetermined level of heat in the motors. Also, in the event that the operator leaves the mower with the two motors turned off but with the main switch key still on, the system will automatically turn itself off after a predetermined time delay and thereby avoid any danger, battery drain, or abuse of the mower.  
           [0013]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0015]    [0015]FIG. 1 is a front perspective view of a lawnmower of this invention.  
         [0016]    [0016]FIG. 2 is a front perspective exploded view of the reel mower of FIG. 1.  
         [0017]    [0017]FIG. 3 is a front perspective exploded view of the handle of FIG. 1.  
         [0018]    [0018]FIG. 4 is a front perspective exploded view of the battery and reel of FIG. 1.  
         [0019]    [0019]FIG. 5 is an electrical schematic view of the electric system employed in this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0021]    The drawings show a conventional reel-type mower  10  which includes a frame structure  11  having two side plates  12  and  13  and cross-frame pieces  14  and  16  as best seen in FIG. 2. There is a conventional rotatable greensmower reel  17  with its usual spiraled blades  18  equally spaced around the reel shaft  19  which is elongated and defines a rotation axis  21  extending along the length of the shaft  19 . There is the usual reel fixed bed knife at  22 , and the blades  18  orbit relative to the shaft  19  and move past the knife  22  for the usual and well-known function of the grass cutting. Also, there is a reel mower rotatable roller  23  at the front of the assembly and, along with an unshown rear roller, it supports the reel mower for movement on the ground.  
         [0022]    [0022]FIGS. 1, 2, and  4  show the above, and they also show a lawn roller  24  included in the assembly and rotatably mounted on the structure  11  through a roller axle  26 . The roller  24  supports the lawnmower assembly on the ground and serves as the traction drive for the lawnmower. Other ground-supporting traction members could be substituted.  
         [0023]    The rotational drive to the reel  17  and the traction roller  23  is through an electrical system which includes two separate electric motors  27  and  28 , respectively. These two motors are a respective part of two branches of electric circuitry herein. The motors  27  and  28  are respectively suitably bolted to the structure side plates  12  and  13  and they are drivingly connected with the reel  17  and the traction roller member  24 . The reel motor  27  suitably drivingly engages the reel shaft  19  for rotating the reel in the forward mowing direction which is leftward in these drawings. The motors  27  and  28  are through Motor Appliance Corp., St. Louis, Mo., model M12160-2.  
         [0024]    The traction motor  28  has a drive pulley  31  thereon, and the pulley  31  connects with a drive belt  32  which drives an idler pulley  33 . Pulley  33  meshes with a drive pulley  34  which in turn drives a belt  36  and a pulley  37  which is drivingly on the roller axle  26 . Thus there is a traction drive train from the motor  28  to the ground-engaging traction member  24 , and thusly the lawnmower is moved in the forward operating direction. That operation may be the grass cutting action of the reel  17  along with the roller action of the roller  24 , or it may be the operation of only the roller  24 , as mentioned.  
         [0025]    [0025]FIGS. 1 and 3 show a handle which is suitably connected with the structure  11  at the handle lower end  39 . The handle upper end has a hand grip portion  41  which the operator can hold in steering the lawnmower. There is a movably mounted bail or operator hand control  42  pivotally connected to the handle  38 , and it is movable toward and away from the grip portion  41 . Two pivot mounting plates  43  are connected with the grip  41 , and the plates  43  present a pivot mounting for a bracket  44  which is attached to the bail  42 .  
         [0026]    In that arrangement, the operator can hold both the grip  41  and the bail  42  while guiding the lawnmower. As will be more clearly seen later, upon release of the bail, the traction drive is interrupted, and the bail is an electric switch manual control. FIG. 1 shows that a bail switch  46  is mounted on the handle  38  in a position to be subject to electrical actuation by forward movement of the bail  42 , and the relationship with the switch  46  may be in any suitable manner. Also, there is a bail lockout lever  47  which is spring-loaded to its active position which precludes the bail  42  from being moved into its active position, and thus the switch  46  is in its “OFF” position. The user can release the lever  47  and then pivot the bail forward for activation of the switch  46  and place the switch in its “ON” position for mower operation.  
         [0027]    Additionally, the vicinity of the handle upper end  42  also includes electrically elements mounted thereon, which are therefore presented to the user for his observation or actuation. An electric and manually controlled switch  48 , through a wire  49 , is mounted on the handle and is connected with the reel motor  27  to control power to the operation of the motor  27 . A battery fuel gage  51  is mounted on the handle and is visible by the user and it is connected through wires  52  into the hereinafter described electric circuitry. The gage is one through Curtis Instruments, Inc., Mt. Kisco, N.Y., as part 906T48HWDAN. A manually controllable key switch  53  is mounted on the handle and is available to the user at the handle location and it is connected in the circuitry through wires  54 . A manually controllable variable resistor, such as a potentiometer  56 , is connected in that branch of the circuitry through wires  57 , and it is mounted on the handle and it controls the power to the traction motor  28  and it has a control handle  58  connected thereto and disposed within easy reach of the user. The potentiometer is through Spectrol Electronics Corp., Ontario, Calif., part 657-2-0-103.  
         [0028]    Thus there are the aforementioned five electric elements of the switch  46 , the switch  48 , the gage  51 , the switch  53 , and the potentiometer control  58 , all of which are available to the user at the convenience of the location of the upper handle  42 . That emphasizes the significance of the walk-behind lawnmower of this invention.  
         [0029]    [0029]FIG. 5 shows the electric circuitry which includes the battery pack  59  shown to have four batteries in the total pack, as also seen in FIG. 4. In addition to the electric elements previously mentioned the circuitry includes an electric sensor in the fuel gage element  51  to sense the level of the electric power in the battery  59  and to register that on an operator readout, of any conventional design, at the gage  51  on the handle, so the operator always knows the power in the battery  59 . The relay is one through said Curtis Instruments, Inc., as part 1178E36480010. The gage  51  is connected to a battery cutout relay  61 , and, upon the occasion of a predetermined low voltage, such as a depth of discharge (DOD) of seventy percent of full charge, a flashing light can signal the operator. At eighty percent of DOD the fuel gage  51  provides a double flashing light and a signal to the battery cutout relay  61  to activate the relay  61  and thereby terminate current to the reel motor  27  through an electric contactor  62  which is connected with the motor  27  through a wire  63 . That forces the operator to discontinue cutting the grass and to ultimately tend to the battery which is protected from deep discharge and consequent harm. However, the system still allows the operator to drive the lawnmower by use of the traction motor  28  and to a service location. The contactors are through said Curtis Instruments, Inc. part SW60P48DCSupp/120.  
         [0030]    After the battery is rectified, the operator must reactivate the system by setting the key switch  53  into the start mode to energize the system and then reactivate the bail  42  and the bail switch  46 . Closing the switch  53  activates a time delay module  64 . Module  64  provides an electrical shutdown system where after fifteen minutes of non-operation, the time delay module will remove power to the entire system. This feature is to render the lawnmower inoperative when it is parked for fifteen minutes, and the re-start sequence will then be employed. The module is through Marlin Technologies, Inc. 1105 Commerce Ct. Horicon, Wis., part M371.  
         [0031]    Another feature of the system is that in the event either motor  27  or  28  is jammed or stalled, such as when the electric current exceeds an amperage for a predetermined length of time, say fifty amps for one-half second, there is a sensor built into each motor that produces an automatic shutdown of that motor. That can be a conventional type sensor, but it is uniquely employed in this system.  
         [0032]    Also of conventional arrangement in the motors is protection against overload, and there is a heat sensor in the motors. Internally built into the motors  27  and  28  is a shutdown sensor that senses heat generation in components in the motors and will shutdown the motor when these components exceed the predetermined heat limit. Again, after the overload is relieved, the start-up sequence is employed to reactivate the lawnmower.  
         [0033]    In the re-start, the key switch  53  is activated to the start position and that energizes the time delay module  64  and the battery fuel gage  51 . Closing the reel control switch  48  and the bail switch  46 , current is directed to the motor contactor  62  and to the reel motor  27 . Current is also directed to a contactor  65  connected with the bail switch  46  for directing current to the traction motor  28 .  
         [0034]    In the FIG. 5 showing, the traction motor  28  is subject to the variable control  56  to permit the operator to select the ground speed of the lawnmower. Selectable walking speeds, rather than having a riding mower speed, is important. In the embodiment of FIG. 5, the reel motor  27  is shown to be controlled by a fixed control  66 . However, in the reel control branch, the control  66  could be replaced by a potentiometer, such as the potentiometer  56 , and then the reel rotation speed would be variable and under the direct control of the operator when a handle-located potentiometer control, like the control  58  is provided for the reel motor  27 . In instances where it is not preferred to have the operator alter reel rotation speed on the mowing site, the embodiment of FIG. 5 is to be employed.  
         [0035]    As viewed in FIG. 5, the lower portion thereof shows a signal light  67  and a manual switch  68  and provision for another motor  69 , such as a groomer motor, if desired. Also, the top location in FIG. 5 shows an electrical connector or plug  71  which is manually connectable for connecting the system with the battery pack  59 .  
         [0036]    [0036]FIGS. 1 and 4 show the presence and the mounting of the battery  59 . The structure cross bars  14  and  16  are fixedly connected with the mower side plates  12  and  13 , and they support a battery tray  70  which includes a planar base  73  and two side rails  72  and  74 , all as one integral unit. There is a floor extension  76  adjustably bolted to the side rails  72  and  74  through bolts, such as bolt  77 , and elongated slots, such as slot  78 , in the side rails  72  and  74 . The extension  76  is also adjustably attached to the tray base  73  by bolts, such as bolt  79  through elongated slots  81 . Screws  82  and  83  extend through the tray assembled base and connect with the mower structure at cross pieces  14  and  16 , with spacers  84  and  86  therebetween.  
         [0037]    In that manner, the battery tray is adjustable fore-and-aft of the mowing direction, and its weight can thus be selectively shifted relative to the reel mower to adjust the weight effective on the mower rollers, such as the one shown front roller  23 .  
         [0038]    The tray  70 , as just described, also has a rear abutment or upright wall  87  affixed as a portion of the tray. A front latch  88  is pivotally attached at pivot pins  89 , and it is a portion of the tray. Tension springs, such as shown spring  91 , urge an upright wall  92  of the latch  88  rearwardly and toward the abutment  87 .  
         [0039]    The battery  59  is shown to be in four separate batteries, all connected in series connection and supported in a battery box base  93  which is rectilinear and upwardly open to receive the four batteries in the shown side-by-side positioning. A battery box top  94  mates with the base  93  to form a complete enclosure of a rectilinear box for the four batteries. The top  94  and bottom  93  are bolted together at respective flanges  96  and  97  with bolts, such as bolt  98 . A handle  99  is attached to the box.  
         [0040]    The latch  88  has an opening  101  therein, and the box  93  has a protrusion  102  and the opening  101  snugly receives the protrusion  102  when the box is sitting on the tray base  73 . Thus, the box back wall  103  abuts the abutment  87  and the box is held down by the engaged latch  88 . The box is restricted at its sides by the overlapping two said rails  72  and  74 . The box has feet  104  which support the battery and box assembly on the tray.  
         [0041]    To remove the assembly of the box and the battery from the mower, the user need only grip a ledge  106  on the latch and pivot the latch forwardly to release at the protrusion  102 . Then, disconnecting the wires at the connector  71 , the assembly can be lifted off the mower through the handle  99 . Replacement of the battery on the mower is achieved by simply lowering the assembly onto the tray, and the latch  88  has a convex curved portion  107  which slidably engages the battery box to pivot the latch forwardly until the battery box is on the tray base  73  and the latch  88  will then automatically connect with the protrusion. Connecting the connector  71  will complete the replacement operation.  
         [0042]    A ground or floor support stand  108  is pivotally connected to the mower  10  on pivot bolts, such as shown bolt  109 , and it extends from end to end on the mower and upwardly in the inoperative position, as seen in FIGS. 1 and 4. Pivoting the stand  108  clockwise, as viewed in FIGS. 1 and 4, will place it underneath the mower  10  and thus will upwardly support the mower off the ground at the back of the mower  10 . That is useful for connecting unshown transport wheels, inspection, and servicing of mower. Tension springs, such as spring  111 , urge the stand upwardly to its shown inoperative position.  
         [0043]    This greensmower may have eight reel blades  18 . Per the reel revolution, the number of blades  18  affect the clip rate. Also, in the FIG. 5 embodiment, the electric control  66  for the reel motor  27  can be arranged in the shop to produce a selected rpm in the motor  27 . Then the user mowing the green will control the clip rate only through the operator presence hand control  58  for adjusting the rpm of the motor  28  and thereby establish the clip rate by the adjustment of only a single control.  
         [0044]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.