Patent Publication Number: US-2004045754-A1

Title: Riding lawn mower with improved radiator system

Description:
REFERENCE TO RELATED APPLICATIONS  
     [0001] This application is a continuation of U.S. patent application Ser. No. 09/910,121 filed Jul. 20, 2001. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates to the field of lawn mowers, and more particularly to riding lawn mowers with an improved radiator system including a top mounted radiator and fan assembly and an apparatus for clearing debris from the radiator.  
       BACKGROUND OF THE INVENTION  
       [0003] Most heavy duty and professional grade riding lawn mowers have water cooled engines that include radiators to transfer the heat away from the circulating water. As is typical in water cooled engines, output pulleys facing forwardly or rearwardly drive one or more belts, which drive pumps, motors and/or compressors. A fan is mounted on the output pulley spindle of one of the pulleys, and the radiator is mounted in planar relation next to the fan so that the fan&#39;s output is primarily directed to the radiator.  
       [0004] In one configuration, the mower&#39;s engine is mounted so that the pulleys (and fan connected thereto) face forwardly of the engine, and are thereby in an optimal position to couple with a hydraulic system therebelow that drives the rear wheels of the mower. This dictates that the radiator be positioned just forward of the fan and just behind the operator seat. Although the fan directs the air flow rearwardly, away from the back of the seat and toward the radiator, a substantial amount of radiative heat radiates from the radiator toward the seat, creating substantial discomfort for the operator.  
       [0005] A consequence of drawing air flow through the radiator in a riding lawn mower is a build up of grass clippings and related debris on the intake side of the radiator. It is desired to minimize the overall length of the mower, and the radiator is therefore positioned fairly closely to the back of the operator seat. This makes it awkward and somewhat difficult to clear the debris from the intake side of the radiator. In some designs, the operator seat is hingedly mounted to the mower frame and may be pivoted away from the radiator. The debris may then be cleared from the radiator by hand or broom or similar implement, although other supporting structure and mower components may still partially obstruct the radiator and make cleaning difficult. Any debris not cleared from the intake side of the radiator decreases the air flow volume that can be drawn across the radiator, thereby decreasing the radiator&#39;s heat transfer rate. In short, the engine is caused to run hotter, which lowers the engine&#39;s efficiency and longevity.  
       [0006] What is needed is an improved radiator system for a water cooled riding lawn mower.  
       SUMMARY OF THE INVENTION  
       [0007] Generally speaking, a riding lawn mower with a water cooled engine includes a radiator system mounted above the engine and with an apparatus for discharging debris that accumulates on the intake screen to the radiator.  
       [0008] A riding lawn mower includes a frame; ground engaging wheels mounted with the frame; at least one cutting deck mounted to the frame; an engine mounted to the frame and operatively connected to drive the ground engaging wheels and the at least one cutting deck, the engine having fluid to be cooled; and, a radiator system. The radiator system includes a housing; a radiator having first and second opposing sides, mounted in the housing and operatively connected with the engine to intake fluid at a first temperature from the engine and to output fluid back to the engine at a second temperature; a screen mounted in the housing and adjacent the first side of the radiator; a bi-directional fan mounted with the housing adjacent the second side of the radiator and operable to direct an air flow in a standard direction first through the screen and then through the radiator and operable as desired to direct an airflow in a discharge direction, opposite the standard direction, first through the radiator and then through the screen; and switch circuitry for switching the fan between the standard and discharge directions; and, wherein the radiator and fan are mounted above the engine.  
       [0009] It is an object of the present invention to provide an improved riding lawn mower with water cooled engine.  
       [0010] It is another object of the present invention to provide an improved radiator system for a riding lawn mower with water cooled engine.  
       [0011] Other objects and advantages of the present invention will become apparent from the following description of the preferred embodiment.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012]FIG. 1 is a rear perspective view of a riding lawn mower  10  with radiator system  11  in accordance with the preferred embodiment of the present invention.  
     [0013]FIG. 2 is a front perspective view of the riding lawn mower  10  of FIG. 1.  
     [0014]FIG. 3 is a side cross-sectional view of the radiator system  11  of the mower  10  of FIG. 1.  
     [0015]FIG. 4 is an exploded perspective view of the radiator system  11  of the mower  10  of FIG. 1.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0016] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and that any alterations or modifications in the illustrated device, and any further applications of the principles of the invention as illustrated therein are contemplated as would normally occur to one skilled in the art to which the invention relates.  
     [0017] Referring now to FIGS. 1 and 2, there is shown a riding lawn mower  10  with radiator system  11  in accordance with the preferred embodiment of the present invention. As with known riding lawn mowers, mower  10  generally includes a frame  14 , rear wheels  15 , front wheels  16 , a water cooled engine  17 , one or more cutting decks  18 , an operator seat  19 , gas tank  20 , and various other controls and attachments. Engine  17  is water cooled and, as such, employs a radiator to transfer heat away from water circulating through passageways defined in engine  17 . Such radiator is contained within radiator system  11 , which is disposed above engine  17  and behind operator seat  19 .  
     [0018] Referring now to FIGS. 1 through 4, radiator system  11  is mounted to mower frame  14  via front frame member  22  and rear frame members  23  and  24 , and generally includes radiator mounting pan  25 , fan unit  26 , radiator  28 , guide channel  29 , gaskets members  30  through  34 , debris screen  37 , end caps  38  and  39 , and cover  40 . Front frame member  22  is generally arched-shaped as seen in FIGS. 1 and 4 and is fixed to mower frame  14  directly behind the mower frame roll bar  43  and operator seat  19  by appropriate means such as bolts (not shown). Rear frame members  23  and  24  are fixed at their lower ends to rear mower frame plate  44  and extend upwardly therefrom, as shown.  
     [0019] Radiator mounting pan  25  includes a floor  45  that defines a central fan opening  46  along with four radiator input/output openings  49 - 52 . Mounting pan  25  further includes a forwardly extending mounting flange  54  and a pair of rearwardly extending mounting flanges  55  and  56 . A mounting plate  57  extends between the angled portions  58  and  59  of front frame member  22 , as shown, and is connected thereat by appropriate means, such as welding. The forward mounting flange  54  of mounting pan  25  is connected to mounting plate  57  with appropriate fasteners such as screws (not shown), and rear mounting flanges  55  and  56  are connected to the upper ends of rear frame members  23  and  24  using appropriate fasteners such as screws (not shown).  
     [0020] Fan  26  is mounted to the underside of radiator mounting pan  25  by appropriate means such as screws in a position to direct airflow through central fan opening  46 . The fan unit  26  depicted in FIG. 4 is representative of any appropriate electrically powered fan. In one embodiment, fan  26  is a 12v, 12 inch electric engine cooling fan commercially available from most automotive parts suppliers. Fan  26  is capable of directing an airflow in a direction roughly perpendicular to the representative surface  62  of fan  26 . Fan  26  is capable of drawing air downwardly through central fan opening  46  and toward engine  17 , and is further capable of having its direction reversed whereby it draws air from below, up through central fan opening  46  and toward radiator  28 .  
     [0021] A radiator is shown represented at  28  and is sized to accommodate the cooling capacity desired by engine  17 , and mounting pan  25  is sized and shaped to receive radiator  28  within its upstanding walls  65 . Radiator  28  includes input and output ports  63  and  64  which extend through corresponding openings  51  and  52  of pan  25  and connect with the remainder of the water based cooling system of engine  17 . Radiator  28  is also designed to connect with and cool the circulating hydraulic fluid of the mower&#39;s hydraulic drive system and includes oil input and output ports, one of which is shown at  66  (FIG. 3). The oil input and output ports extend through the corresponding input and output openings  49  and  50  in radiator mounting pan  25 . Radiator  28  includes a fluid fill access port  67 . Radiator  28  is stabilized by connecting it to radiator mounting pan by any appropriate means such as nuts and bolts (not shown).  
     [0022] Guide channel  29  includes an upstanding, rectangular-shaped flange  69 , and the four gasket members  31 - 34  are firmly received over each the four sides of upstanding, rectangular-shaped flange  69  to form a substantially continuous rectangular seal.  
     [0023] Debris screen  37  consists of a substantially rectangular sheet of metal screen or perforated metal, the sheet having a series of mutually parallel right angle bends to form a rigid, generally rectangular screen, as shown. Debris screen  37  could be made of any appropriate material and in any desired configuration so long as it has a pore size small enough to filter out the desired debris (grass clippings, dirt clumps, rocks, sticks, etc.), but large enough to permit sufficient air flow to maintain effective cooling action in radiator  28 . End caps  38  and  39  are shaped substantially as shown to close off the open ends of debris screen  37 . End caps  38  and  39  are not perforated, but could be if desired. The ridges created by the series of right angle bends of debris screen  37  more than double the surface area of the screen and decrease the rate at which accumulating debris blocks airflow through the screen.  
     [0024] Cover  40  includes a pair of hinge sleeves  71  and  72  that align coaxially just to the outside with hinge sleeves  73  and  74  located on the rear, bottom edge of radiator mounting pan  25 . Hinge pins extend through each pair of mating hinge sleeves  71 / 73  and  72 / 74 , and cover is thereby hingedly connected to mounting pin  25 . Cover  40  has an upper surface  78  that defines a rectangular opening sized to receive debris screen  37  therethrough. The opposing outer, rectangular strips  80  and  81  of debris screen  37  act as mounting flanges for screen  37 , and likewise, end caps  38  and  39  have rectangular mounting flanges  82  and  83 . The mounting flanges  80 - 83  are connected up against the under side of upper surface  78  of cover  40  so that the remaining portions of debris screen  37  and end caps  38  and  39  extend up through opening  78 , as shown in FIG. 3. Debris screen  37  and end caps  38  and  39  are connected with cover  40  by appropriate means such as pop rivets, screws or clips. Cover  40 , guide channel  29  and gasket members  31 - 34  are sized and configured so that when cover  40  is hingedly closed (as seen in FIG. 3) the under side of mounting flanges  80 - 84  engage with and form a seal with gasket members  31 - 34 .  
     [0025] In operation, fan  26  is operated to draw air flow down through debris screen  37 , guide channel  29 , radiator  28 , central fan opening  46  and through fan  26 . With the intake for the airflow to radiator  28  at nearly the highest point possible of mower  10 , the rate of collection of debris against the debris screen  37  is reduced. Further, the increased surface area of debris screen  37  decreases the rate at which the screen is clogged as debris accumulates.  
     [0026] Fan  26  is bi-directional. That is, the direction of the fan blade of fan  26  can be reversed either by changing polarity of the electrical input to fan  26  or by activating a direction reversal switch that is part of fan  26  or is externally connected to fan  26 . Such circuitry is contemplated to be operated manually at the fan  26 , at a place proximal and more convenient to an operator sitting in operator seat  19 , and/or incorporated into the ignition system of mower  10 . Such connection with the ignition system is contemplated to include operation whereby, sometime immediately at or shortly after startup of mower  10 , fan  26  is operated in the reverse, discharge direction for a preset period of time, e.g.  10  seconds, and then is either stopped or is reversed to run in the standard direction. In operation then, when mower  10  is started, fan  26  operates in the reverse, discharge direction which directs airflow from below fan  26  up through opening  46 , radiator  28 , guide channel  29  and through screen  37 . The effect is to direct a blast of air through screen  37  which clears the majority of debris collected thereon, thereby permitting nearly unrestricted airflow through radiator system  11  during normal operation. After the preset discharge blast (e.g. 10 seconds), the direction of fan  26  is automatically changed back to its standard operation direction, that is, down through screen  37 , radiator  28  and through fan  26 . In addition to the automatic discharge blast activated at startup, it is further contemplated that radiator system  11  enable the operator to manually run fan  26  in the discharge direction at any time during operation should debris screen  37  accumulate too much debris, that is, the screen becomes so clogged that the air flow becomes significantly blocked and cooling efficiency of radiator  28  is significantly reduced. Such manual discharge fan operation is contemplated to include a switch that, upon activating, simply runs the fan in the reverse, discharge direction until the switch is turned off. Alternatively, such switch could be made to be activated or depressed, the result being a running of the fan in the reverse, discharge direction for just a preset amount of time (e.g. 10 seconds), such operation constituting a discharge blast.  
     [0027] The electrical circuitry is further contemplated to include a temperature sensor coupled with radiator  28  to activate fan  26  in the standard direction whenever the temperature of the coolant exceeds a preset value. The electrical components and connections to permit fan  26  to be run in the standard direction and to be reversed automatically and/or manually, at mower startup and/or during normal operation, and/or for as long as the switch is activated or for a preset time (a blast period) is not disclosed herein and is believed to be within the knowledge of one skilled in the art.  
     [0028] The drawings presented in FIGS.  1 - 4  are for illustration purposes, and it is to be understood that elements unnecessary to the present invention may not be shown or may be omitted to permit a clearer view of other components, such omitted elements including fasteners, linkages, fittings, and so on. Also, some components are shown as representative elements and without detail. For example, radiator  28  and fan  26  are shown generally in outline form, it being understood that radiator  28  has cooling fins, and fan  26  has a fan blade, spindle, electric wires, and so on. Also for example, input and output ports  63  and  64  of radiator  28  are not shown connected with the cooling passageways of engine  17 , it being understood that such connections exist as is standard with water cooled engines having radiators.  
     [0029] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrated and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.