Abstract:
The discharge chute opening and closing apparatus for lawn mowers comprises a vertical bar fixedly attached to a pivot bar, rotatably mounted between first and second pivot stanchions; a pivot arm fixedly attached to the pivot bar at a first end and engaged with a cam pin at a second end; a cam plate comprising a cam pin and a drive pin, rotatably attached to a third pivot stanchion; a lift plate rotatably attached to the third pivot stanchion and fixedly attached to a chute door being operably engaged by the cam and drive pins; a second lift plate fixedly attached to a fourth pivot stanchion further comprising a spring attachment; a spring attached at a first end to the spring attachment of the lift plate and attached at a second end to a spring mounting bracket wherein the spring assists in maintaining the position of the chute door.

Description:
CROSS REFERENCE TO A RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/421,460 filed Oct. 25, 2002. 

   FIELD OF THE INVENTION 
   The subject invention pertains generally to lawn mower apparatus, and in particular relates to an apparatus and a technique for quickly opening a lawn mower chute. 
   BACKGROUND OF THE INVENTION 
   Power operated lawn mowers typically have a shroud with depending sides that extend over and surround the rotating cutter blades within the shroud. Typically, the shroud is fitted with a discharge chute through which the cut grass exits to be either passed to a collection container for later disposal, or is deposited on the lawn in the form of mulch. In certain areas, however, it is imprudent to leave the discharge chute open; such situations exist when the lawn mower is being used near buildings or around people, as small stones or other dangerous objects may be discharged at a relatively high velocity, causing damage or injury. 
   To counter this problem, the prior art has developed a number of techniques for permitting the discharge chute to be alternately opened and closed in a relatively rapid manner. Examples of such prior art arrangements are disclosed below. As more fully explained herein, these arrangements suffer from various drawbacks. 
   U.S. Pat. No. 4,135,351 to Akgulian discloses a rotary lawnmower grass mulcher assembly having a mower housing and a discharge opening covered by a pair of plates having air holes there through. The air holes are offset between the two plates, which allows for the discharge of air while maintaining the grass clippings in the mower housing for mulching. 
   U.S. Pat. No. 4,45,312 to Cartner discloses a mower head with movable guard for an articulated boom assembly attached to a mow tractor. The movable guard may be opened via a hydraulic means for allowing the mower blade to cut saplings and the like. 
   U.S. Pat. No. 5,040,364 to Deegan discloses a lawnmower having a selectable discharges means. The lawnmower described comprises a cutting deck having a plurality of discharge exit ports, each covered with a closure means. Each closure means is connected to a control lever, which operates to open and close the closure means via a cable attachment. 
   U.S. Pat. No. 5,048,279 to Badawey et al. discloses a leaf mulcher for use with a rotary blade power lawnmower. The leaf mulcher comprises a screen, which covers the outlet of the lawnmower. The screen is offset to provide a space between the outlet and the screen thereby allowing a portion of the grass clippings to escape from outlet without passing through the screen. 
   U.S. Pat. No. 5,133,175 to Dumbrell discloses a safety flap for power-operated lawnmower the apparatus remains in the closed position due to the force of gravity. 
   U.S. Pat. No. 5,284,007 to Poe et al. discloses a mulching and shredding attachment for the use on a lawnmower or lawn vacuum, which is held in place by a bracket comprising a lever and a clevis pin. Removal of the pin allows for the apparatus to be engaged or disengaged. 
   U.S. Pat. No. 5,657,620 to Thagard et al. discloses a device for mowing, cutting and mulching. The device is generally attached to a tractor power drive, and comprises a shroud mechanism that may be mechanically opened. When the shroud mechanism is mechanically opened it exposes the cutting means for removing brush and saplings. 
   Finally, U.S. Pat. No. 5,826,417 to Evans discloses an operator control deflector plate for the discharge chute of a riding lawnmower. The deflector plate comprises a series of air holes large enough to allow the passage of grass, however, small enough to prevent the passage of objects sufficient to cause physical injury or property damage. The device may be selectively opened by a lever mechanism mounted to the lawnmower cutting deck. 
   Despite these prior art efforts, there remains a need for discharge chute opening and closing apparatus that is rugged and operates to quickly move the cover for the discharge chute between the open and closed positions. All documents and publications cited are incorporated by reference to the extent not inconsistent with the explicit teachings set forth herein. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a discharge chute opening and closing apparatus for lawn mowers that is rugged, reliable and operates to quickly open and close the discharge chute. 
   The discharge chute opening and closing apparatus for lawn mowers comprises, in combination, the following: a vertical bar fixedly attached to a pivot bar, rotatably mounted between first and second pivot stanchions; a pivot arm fixedly attached to said pivot arm at a first end and engaged with a cam pin at a second end; a cam plate comprising a cam pin and a drive pin rotatably attached to a third pivot stanchion; a lift plate rotatably attached to the third pivot stanchion and fixedly attached to a chute cover being operably engaged by the cam and drive pins; a second lift plate fixedly attached to a fourth pivot stanchion further comprising a spring attachment; a spring attached at a first end to the spring attachment of the lift plate and attached at a second end to a spring mounting bracket wherein the spring assists in maintaining the position of the chute cover. 
   The vertical bar has a first end defining a handle and a second end fixedly attached to a pivot bar for translating torque from the operator to the pivot bar. When engaged by the user, the handle operates to open and close the chute cover. The pivot bar is rotatably disposed between a first pivot stanchion and a second pivot stanchion and is further attached to a generally horizontal pivot arm. Movement of the vertical handle translates to movement of the pivot arm. 
   The horizontal pivot arm has a first end attached to the pivot bar and a second end comprising a crank plate. The crank plate further defines an aperture that receives a a first end of a cam pin. Movement of the pivot arm translates torque to the cam pin, which is fixedly attached through and causes rotation of a cam plate. The cam plate is rotatably attached to a third pivot stanchion and comprises a cam pin and a drive pin. As the cam plate is rotated about its axis, a second end of the cam pin engages and raises a first lift plate attached to the chute cover door. 
   The chute cover door fixedly attached to the first lift plate and a second lift plate wherein the second lift plate is rotatably attached to a fourth pivot stanchion. When closed, the chute cover door is generally in a substantially vertical position. When opened, the chute cover door is opened past the horizontal position to allow for the unimpeded discharge of grass clippings. 
   The opposite movement of the handle generally closes the apparatus. The pivot arm essentially pushes down on the cam pin and the cam plate is rotated in an opposite direction. As the cam plate rotates the drive pin engages the lift plate and pushes the lift plate forward wherein gravity or an attached spring operates to complete the closing process. 
   By way of example, the apparatus may further comprise a spring attached between the second lift plate and a spring mount to facilitate the opening of the chute door. The spring can be mounted to provide constant tension between the lift plate attached to the chute door and the spring mount attached to the cutting deck. When the apparatus closed, the spring can operate to maintain the chute cover in the closed position. When the chute cover apparatus is opened, the spring can operate to maintain the chute cover in the open position. 
   The apparatus may include a staybar that allows for the partial opening of the apparatus when in operation. The staybar can be attached to a lift plate and provide structural support therefore. The staybar can comprise a design having an offset center of gravity that allows the staybar to maintain an upright position as the apparatus is opened slowly. The staybar can maintain this upright position until the chute cover reaches a critical angle, then the staybar will rotate allowing for the chute cover to fully close. Such a feature is particularly helpful when a partial discharge of grass clippings is desired. 
   In a further embodiment the apparatus can comprise a stop bolt attached to an end of the pivot arm to prevent the pivot arm from over rotating and becoming disengaged from the cam pin. 
   In another embodiment a limiting means may be installed to prevent the chute cover from over rotating and causing damage to the components. In a preferred embodiment the limiting means comprises a shock pad made from a resilient material such as rubber, nylon, plastic or the like for eliminating or reducing the wear caused by two metal parts coming into abrupt contact with one another. 
   Further objects and advantages of the present invention will become apparent by reference to the following detailed disclosure of the invention and appended drawing wherein like reference numbers refer to the same feature, component, or element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top plan view of the discharge chute opening and closing apparatus according to the present invention, fitted to the shroud of a lawn mower; 
       FIG. 2  is a rear perspective view of the apparatus shown in accordance with the present invention. 
       FIG. 3  is a side perspective view of the apparatus according to the present invention, with the chute cover removed. 
       FIG. 4  is a side plan view of a pivot upright assembly of the present invention. 
       FIG. 5  is a front plan view of a pivot upright assembly of the present invention. 
       FIG. 6  is a side fragmentary view of the chute cover assembly of the present invention. 
       FIG. 7  is a side plan view of the staybar of the present invention. 
       FIG. 8  is a front sectional view of the staybar/lift plate assembly of the present invention. 
       FIG. 9  is a side fragmentary view illustrating a one-quarter opened chute cover assembly. 
       FIG. 10  is a side fragmentary view illustrating a half opened chute cover assembly. 
       FIG. 11  is a side fragmentary view illustrating a fully opened chute cover assembly. 
       FIG. 12  is a side fragmentary view illustrating a one-quarter closed chute cover assembly. 
       FIG. 13A  is a side fragmentary view of the cam plate/lift plate assembly of the present invention in the closed position. 
       FIG. 13B  is a front fragmentary view of the pivot arm assembly of the present invention in the closed position. 
       FIG. 14A  is a side fragmentary view of the cam plate/lift plate assembly of the present invention in the partially opened position. 
       FIG. 14B  is a front fragmentary view of the pivot arm assembly of the present invention in the partially opened position. 
       FIG. 15A  is a side fragmentary view of the cam plate/lift plate assembly of the present invention in the partially opened position. 
       FIG. 15B  is a front fragmentary view of the pivot arm assembly of the present invention in the fully opened position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to  FIG. 1 , an opening and closing lawnmower chute cover apparatus is illustrated and generally designated by the reference numeral  10 . 
   The apparatus  10  is designed for use with a lawn mower having a shroud  12  with an upper, generally horizontal surface  11  and a generally vertical depending skirt  13 . The shroud  12  includes a chute opening  14  (shown by dotted line in  FIG. 1 ) along a side  16  in the skirt  13 . The opening and closing apparatus  10  is fitted along an area  18  of the shroud upper surface  11  which extends generally parallel with the chute opening  14 . 
   The apparatus  10  is provided with a chute cover  20  which comprises a first chute cover portion  22  extending across and generally parallel with the area  18  and a second portion  24  extending generally vertically over the chute opening  14  and parallel with side  16 , when the chute cover  20  is in the closed position, as depicted in FIG.  1 . 
   The apparatus  10  comprises a first plate  26  having opposing ends  28 ,  29 , a second plate  30  having opposing ends  32 ,  34  and an extension plate  38  having opposing ends  40 ,  44 . As depicted in the drawings, the first plate  26  lies along the upper shroud surface  11  in the area  18  generally parallel with the side  16 , the second plate  30  lies generally perpendicular to the side  16  along the shroud surface  11  and the extension plate  38  is fitted at its first end  40  via fastener  42  to the second end  29  of plate  26 , with the second end  44  of extension plate  38  extending angularly away from the side  16  along shroud surface  11 . It will of course be understood by those skilled in the art that the plates  26 ,  30  and  38  may be formed of a unitary plate member. The plates  26 ,  30  and  38  are attached to the shroud  12  via fasteners, such as fasteners  36  and  42 . 
   In accordance with the present invention, the apparatus  10  comprises at least four pivot uprights  46 ,  48 ,  50  and  52 . The first pivot upright  46  is fixed to and extends generally vertically from the proximal end  32  of the second plate  30  and the second pivot upright  48  is fixed to and extends generally vertically from the second end  34  of the second plate  30 . The third vertical upright  50  is attached along the second plate  30  in spaced relation to the first upright  46 , and rearwardly with respect to the side  16  of shroud  12 , as shown in FIG.  1 . The fourth pivot upright  52  is attached to the distal end  44  of the extension plate  38 . 
   Referring next to  FIGS. 4 and 5 , with specific reference to pivot upright  50 , each pivot upright  46 ,  48 ,  50  and  52  includes a stanchion  54  atop which is affixed a bearing support member  56  into which is fitted a generally circular bearing  58  with a central bore  60 . It will be understood by those skilled in the art that the construction details of the pivot uprights  46 ,  48 ,  50  and  52  are all identical to that shown specifically with reference to pivot upright  50  in  FIGS. 2 and 3 . Each of which is adapted to rotatably support a cylindrical shaft that is rotatable about a central axis  62  extending through the opening  60  in the corresponding pivot upright. 
   Referring again to  FIG. 1 , the pivot uprights,  46 ,  48  fixed to the opposing ends of plate  30  rotatably support a main pivot bar  64  having a first end  66  which is pivotally secured with the first pivot upright  46  and a second, distal end  68  which is pivotally secured with the second pivot upright  48 , so that the main pivot bar  64  is rotatably suspended between uprights  46  and  48  above the surface of the plate  30 . The positioning of the main pivot bar  64  is maintained at the respective ends  66  and  68  thereof via lock nuts  70  (at end  66 ) and bolt  72  welded to pivot arm  102  near end  104 , and lock nut  76  (at end  68 ) and bolt  74  welded to pivot bar  64  at end  68 , together with corresponding threads on those ends. Similarly, as shown on the right side of  FIG. 1 , pivot upright  50  has associated lock nuts  78 ,  80  pivotally supporting pivot rod  82 , and pivot upright  52  has associated lock nuts  84 ,  86  which hold in place pivot rod  88 . Rods  82  and  88  together with associated hardware are described in greater detail below. 
   Turning again to the construction details of the apparatus  10  associated with the second plate  30 , an upstanding bracket  90  is fixed to the upper surface of the second plate  30  and extends above the main pivot bar  64  so as to support a shock pad  92  above the main pivot bar  64 . As is evident from  FIG. 2 , the shock pad  92  supports the chute cover  20  by engaging the first portion  22  when the chute cover  20  is in an open position. 
   With continuing reference to  FIG. 1 , a brace  94  is fixed along the main pivot  64  and has a generally vertical handle  96  fixed thereto at a proximal, lower end  98  of the handle. As will be appreciated by those skilled in the art, the upper, distal extremity  100  of the handle  96  can be used by an operator to effectuate a rotation of the main pivot bar  64 , which in turn effectuates rotation of pivot arm  102  about its proximal end  104  which is, in turn, fixed to the main pivot bar  64  in abutting relationship with bolt  72  associated with pivot upright  46 . At the same time, the opposing, distal end  106  of pivot arm  102  is rotated away from the area  18  of shroud surface  11 . A cam plate assembly including cam plate  112  and crank plate  108  are cooperatively attached with the distal end  106  of the pivot arm  102 , so as to effectuate the raising and lowering of lift plate  114 . Lift plate  114  is fixed at a first end  116  to the first portion  22  of chute cover  20 , and at the opposing end  118  is pivotally mounted along shaft  88  associated with pivot upright  52 . Therefore, when the upper extremity  100  of the handle  96  is moved in a direction generally parallel with the direction of the side  16  and chute opening  14 , the main pivot bar  64  is rotated in the manner described above so as to lift the distal end  106  of the pivot arm  102 , thereby effectuating the raising or lowering of the cover  20 . The cover  20  is shown in the closed position in  FIG. 1 ; when raised to the open position, the first surface  22  of the cover  20  rests upon the shock pad  92 . 
   Turning now to  FIGS. 6 and 3 , the apparatus  10  is shown in a closed position. As can be seen from  FIG. 6 , the spring  120  is attached at a first end  132  to an extension  147  of the pivot point  131  of the staybar  125  and at a second end  134  to the spring mounting bracket  122 . When in the closed position, the spring  120  operates under tension to pull the chute cover  20  closed, thus maintaining its position. This is caused by the spring  120  being attached to a point  133  on the lift plate  124  that is lower than the lift plate pivot point  135 . As the chute cover  20  begins to open, as depicted in  FIG. 9 , the spring  120  begins to stretch. As the chute cover  20  is opened further, as depicted in  FIG. 10 , the spring  120  is under its highest tension as the lift plate  124  passes the apex of the rotation about the lift plate pivot point  135 . As the pivot point  131  of the staybar  125  passes the apex of the lift plate  124  rotation, the spring  120 , under tension acts to now pull the chute cover  20  to an open position. At this point, the spring  120  operates to maintain the chute cover  20  in an open position, as depicted in FIG.  11 . The chute cover  20  will remain in the open position until such time as the handle  100  is moved in the opposite direction to effectuate the closing of the chute cover  20 . 
   As is shown in  FIG. 11 , the first chute cover portion  22  comes to a rest at a shock pad  92  that operates to limit the rotation of the chute cover  20 . The shock pad is attached to an upstanding bracket  90  and can comprise a resilient material to reduce the amount of wear caused by abrupt metal-to-metal contact. 
   Referring next to  FIG. 7 , the staybar  125  comprises a lower end  129  and an upper end  127 . The pivot point  131  of the staybar  125  passes through the upper portion of the lower end  129 . Because of the configuration of the staybar  125 , its center of gravity C ensures that the staybar  125  maintains the appropriate of the chute cover  20 . 
   When the apparatus  10  is partially engaged by the operator, the position of the staybar  125  is changed and the staybar  125  moves from an angled resting position, as depicted in  FIG. 6 , to an upright position, wherein the lower end  129  of the staybar  125  is generally flat against the surface  11  of the second plate  30 . In this position the staybar  125 , through its connection  133  with the lift plate  124  maintains the chute cover  20  in a partially opened position. 
   To reset the staybar  125 , the chute cover  20  should be fully opened. When the chute cover is  20  is sufficiently opened, the stop pin  136  engages the upper end  127  of the staybar  125  and rotates it in the same direction as the chute cover  20 . When the center of gravity C rotates over and beyond the pivot point  131  of the staybar  125 , the upper end  127  of the staybar  125  rotates entirely over as a result of gravity. At this point, the staybar  125  is reset and when the operator closes the chute cover  20 , the chute cover  20  will close entirely. 
   Referring now to  FIG. 8 , the staybar  125  and lift plate  124  assembly is shown. Through the lift plate  124  and staybar  125  pivot point  131  passes a through bolt  139  held in place by a first lock nut  141 , spaced by washers  143  and secured by a pair of jam nuts  145 A,  145 B. The through bolt  139  is extended beyond the jam nuts  145 A,  145 B and further comprises a spring attachment point  147  and a second lock nut  149 . 
   Turning next to  FIG. 9 , as the chute cover  20  is opening, the pivot arm  102  is activated by handle  96  that actuates crank plate  108  by engaging the cam pin  110 , as depicted in  FIGS. 13A and 13B . At rest the pivot arm  102  is in a generally horizontal position. When rotated about the pivot arm axis  150 , the distal end  106  of the pivot arm  102  is elevated. The crank plate  108  attached to the distal end  106  of the pivot arm  102  engages the cam pin  110  on a first side through the aperture  109 . As the pivot arm  102  is raised, the crank plate  108 , in combination with the cam pin  110 , operates to rotate the cam plate  112  about the cam plate pivot point  88 . 
   As the cam plate  112  rotates, a second end of the cam pin  110  engages the lift plate  114 , attached to the chute cover  20 , and causes the lift plate  114  to rotate about pivot rod  88 , as depicted in  FIGS. 14A and 14B . Once the actual centerline of the spring  120  passes above the center of pivot rod  88 , the tension of spring  120  continues the rotation of lift plate  114  until the chute cover  20  is completely open and contacts shock pad  92 . It will be understood by those skilled in the art that the pivot arm  102  moves the chute cover  20  only to a rotation position where the spring attachment  147  passes the apex of rotation the center line of the pivot rod  82 , and the spring  120  then completes the chute cover  20  opening process; otherwise, the chute cover  20  could only be fully opened as a result of the inertial moment of the chute cover rotation as a result of travel limitations of the pivot arm  102 . 
   It will be appreciated by those skilled in the art that the over rotation of the pivot arm  102  will cause the cam pin  110  to exit the aperture  109  and disengage from the crank plate  108 . To limit rotation of the pivot arm  120 , stop bolts  155  may be attached the pivot arm  102 , thereby decreasing the occurrence of detachment. 
   With continuing reference to  FIG. 9 , also note that when the chute  20  is partially open, the staybar  125  is rotated due to its offset center of gravity C. When the chute  20  is opened slowly, the staybar  125  rotates into the position shown in  FIG. 9 , holding the chute cover  20  in a partially open position, permitting the vertical handle to be released while the staybar  125  is in this position. 
   Reference is now made to  FIG. 10 ; as the chute is rotated by the handle  96  to the position shown, the center line force of the spring has moved above the pivot point of the chute cover  20 , and spring tension completes the chute cover  20  opening, as described above, without force being exerted on the handle  96 . The position of the staybar  125  during that continued movement control is continued until the chute cover  20  is fully opened, as shown in FIG.  11 . 
   Next referring to  FIG. 12 , the closing operation of the apparatus  10  will now be described. The pivot arm  102 , when actuated by handle  96 , actuates crank plate  108  by engaging the cam pin  110  of cam plate  112 , causing rotational movement of the cam plate  112  until the cam pin  130  contact lift plate  114  and rotates it about the center line of pivot point  88 , as depicted in  FIGS. 15A and 15B . Rotation continues until the centerline of the spring  120  passes below the apex of the rotation about the pivot point  82 ; thereafter, spring tension continues the rotation of the lift plate  124  until the chute cover  20  is closed. As indicated in  FIG. 12 , the staybar  125  stays in the rotated position due to the inertia and the center of gravity C of the staybar  125 . It will be noted that in the closing operation, the pivot arm  102  has travel limitations and relies upon the tension of the spring  120  to complete the closing of the chute  20  (i.e., the center line of the spring  120  must pass below the center of pivot point  82  in order to complete the closing of the chute  20 ). 
   Inasmuch as the preceding disclosure presents the best mode devised by the inventor for practicing the invention and is intended to enable one skilled in the pertinent art to carry it out, it is apparent that methods incorporating modifications and variations will be obvious to those skilled in the art. As such, it should not be construed to be limited thereby but should include such aforementioned obvious variations and be limited only by the spirit and scope of the following claims.