Patent Publication Number: US-6708472-B2

Title: Lawn mower having disabling feature

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 09/633,007, filed Aug. 4, 2000, now U.S. Pat. No. 6,513,310, which itself claims the benefit of and incorporates by reference U.S. Provisional Patent Application Serial No. 60/147,370, filed Aug. 5, 1999, entitled “Lawn Mower Designs”. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to lawn mowers, and particularly relates to riding and walk-behind mowers. One aspect of the invention particularly relates to the use of a device which causes the lawn mower to stop cutting and/or moving, when the lawn mower contacts a foreign object when in reverse. 
     BACKGROUND OF THE INVENTION 
     Lawn mowers are well known. Reference is made to the many Snapper and other lawn mowers on the market. 
     Although such configurations include advantages, there is always room for improvement. 
     Therefore it may be seen that there is a need in the art for an improved lawn or other vegetation cutting device. 
     SUMMARY OF THE INVENTION 
     The present invention provides lawn mower features as set forth below. 
     Generally described, the present invention overcomes deficiencies in the art by providing an apparatus which disables the cutting blade and/or drivetrain of a lawn mower when a foreign object is contacted. 
     It is further object of the present invention to provide an improved lawn mower which has improved operating features. 
     It is further object of the present invention to provide an improved lawn mower which has improved operating features when in reverse. 
     It is further object of the present invention to provide an improved lawn mower which has improved operating features when cutting in reverse. 
     It is further object of the present invention to provide an improved lawn mower which has improved operating features when cutting in reverse near obstacles. 
     It is further object of the present invention to provide an improved lawn mower which has improved operating features when cutting in reverse in high grass or other vegetation. 
     It is a further object of the present invention to provide an improved lawn mower having features which make it easy to operate. 
     Other objects, features, and advantages of the present invention will become apparent upon reading the following detailed description of the preferred embodiment of the invention when taken in conjunction with the drawing and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a left side elevational view of a lawn mower  10  according to one embodiment of the present invention, which includes the use of a contact bar assembly  20  according to the present invention. 
     FIG. 2 is a rear elevational view of an isolated contact bar assembly  20  (including an extension flap assembly  30 ), illustrated relative to rear wheels  14  (shown in phantom). A portion of a trip lever  40  is also shown contacting the extension flap  30 . 
     FIGS. 3A and 3B are illustrated views of an extension flap  30  as used in connection with a contact bar assembly  20 . This is a partial view of the contact bar assembly  20 , with the extension flap  30  shown in cross-section and in contact with a portion of the trip lever  40 . 
     FIG. 4 is an isolated view of the trip lever  40 , shown in engagement with a slide member  50 . The latch member  46  of the trip lever  40  is shown in engagement with the latch slot  52  of the slide member  50 , which is shown partially and in cross-section. 
     FIG. 5 is a view of a portion of that shown in FIG. 4, except that the trip lever  40  is shown slightly rotated, and the slide member  50  has moved to the left due to disengagement with the trip lever  40 . 
     FIG. 6 is a pictorial illustrated view of the slide member  50 , shown in connection with various associated elements. 
     FIG. 7 is a cross-sectional view of a bushing  80 , shown in conjunction with other elements shown in cross-section, namely a trip lever  40 , slide  50 , and a fastening nut and bolt. 
     FIG. 8 is a partial pictorial view of a left rear portion of a lawn mower apparatus according to the present invention, illustrating a reset lever  90  pivotably attached relative to the frame  12 , as well as a reverse bar spring rod  26  and a reverse bar spring  27 . 
     FIG. 9 is a pictorial partial view of a clutch drag link assembly  60 , attached to a yoke flange  85 , which is itself attached relative to a conventional yoke  86 , which is configured to rotate about a yoke pivot axis  88 . 
     FIG. 10 is an illustrative view showing various things the “disabling device”  3000  can control, including a declutching device  4000 , engine stop  5000 , brake  6000 , and blade stop  7000 . Engine stop can be done by use of engine kill switches and associated circuitry such as known in the art. Blade stop can also be effected as known in the art, such as by moving a pulley or by deactivating a BBC (Blade Brake Clutch). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference is now made to the drawings, in which like numeral indicate like numeral throughout the several views. 
     General Construction and Operation 
     The configuration of FIGS. 1-10 include what would be referenced as a “no drive on contact” bar assembly such as  20 . Contact with the bar assembly disengages the drive and applies the brake. A reset lever is also provided for reset purposes. 
     A pivoting bar is used to push a trip lever. This disengages the drive and can also apply the brake. 
     Engine kill or blade stoppage alone could also be provided. 
     More Detailed Discussion 
     Reference is now made to FIGS. 1-9, which describe a configuration which may be referenced as a “no drive in contact” feature. Generally described, this feature disengages the drive of a self-propelled lawn mower should the lawn mower come in contact with a foreign object in a particular manner. 
     Lawn mower assembly  10  (See FIG. 1) 
     A lawn mower assembly  10  is provided for use with the present invention. This lawn mower  10  shown in FIG. 1 is of a “rear engine rider” configuration, although other configurations are contemplated without departing from the spirit and scope of the present invention. The lawn mower  10  illustrated in FIG. 1 is shown in a side elevational view with its forward moving direction being toward the viewer&#39;s left. 
     The lawn mower  10  includes a frame  12 , two front wheels  13 , two rear wheels  14 , a seat  15 , a steering member  16 , and a pair of rear frame members  17  and attached to the rear of the vehicle. 
     Underneath the frame is positioned a cutting blade housing  18  which covers a cutting blade  19 . 
     Positioned towards the rear of the apparatus is a pivoting reverse contact bar assembly  20 . 
     Reverse Contact Bar Assembly  20  (See also FIG. 2) 
     The reverse contact bar assembly  20  is pivotably mounted relative to the overall frame of the lawn mower apparatus  10 , and is spring-loaded into a particular position along its pivoting range. Upon contact with an obstacle such as shown in FIG. 3A, the reverse contact bar assembly  20  is “tripped”, which through a series of links causes both the cutting blade  19  and the drive clutch to be disengaged, thus stopping the cutting blade and preventing the engine from driving the rear drive wheels. 
     FIG. 2 shows an overall isolated view of the reverse contact bar assembly  20  according to the present invention. This assembly  20  includes the following: 
     a bent bar portion  21 ; 
     two braces  22 ; and 
     a pivoting extension flap member  30 . 
     The bent bar portion  21  may be seen as being bent around several bends, and is attached to the two brace members  22 . The brace members  22  include at least two holes at their marginal ends, each hole being configured to accept the cross-section of the bent bar portion in a pass-through manner. The brace members  22  are in the embodiment shown welded relative to the bent bar portion  21 . Thus the bent bar portion  21  and the two brace members  22  combine to form a unitary subassembly. 
     The reverse contact bar assembly  20  pivots relative to the frame of the lawn mower assembly  20  about Pivot Point PP shown in FIG.  1 . As described in later detail this pivoting could be referenced as being between a first, “set”, position, and a second, “tripped” position. Also as described in later detail, the reverse contact bar assembly  20  is spring-loaded towards its set position by a spring  27  such as shown in FIG. 8 or some other suitable bias device. 
     In one preferred embodiment, a pivoting extension flap member  30  is pivotably attached to the lower portion of the bent bar portion  21 , such that the pivoting extension flap member  30  is allowed to pivot about a substantially horizontal axis when the lawn mower is positioned on level ground. 
     Reference is now made to FIGS. 3A and 3B to illustrate the pivoting feature provided by the pivoting extension flap member  30  according to the present invention. The arrows show the general movement of the lawn mower. 
     In FIG. 3A, the flap member  30  is shown in its “normal” position, with its primary planar surfaces being substantially vertical. In this configuration, the lower edge of the pivoting extension flap member  30  can be seen to be somewhat below the lowermost portion of the bent bar portion  21 . 
     In the situation shown in FIG. 3A where the operator is moving the apparatus in reverse, it may be understood that an obstacle such as  1000  may be encountered. As discussed in detail elsewhere in this application, this causes pivoting of the reverse contact bar assembly  20 , which causes further mechanical actions described later below. 
     FIG. 3A is now compared with FIG.  3 B. In the FIG. 3B situation, the pivoting extension flap member  30  is encountering some “high grass”  2000  and, which causes it to pivot to allow for the high grass to pass thereby with less drag. However, it may be understood that such a pivoting feature is only intended to occur when the apparatus  10  is being moved in its forward direction as shown by the arrow in FIG.  3 B. Preferably, in this situation, the trip lever  40  is not tripped as described later. 
     In one embodiment, the pivoting extension flap member  30  is spring-loaded into a down position, such that a lower edge of the gate is positioned approximately 2″ below the lower most surface of the ½″ rod used for the bent bar portion. 
     The pivoting extension flap member  30  is pivotably attached to relative to the lower portion of the bent bar portion  21  by use of various fastening brackets  32 , positioned at various locations along the length of the relatively elongate pivoting extension flap member  30 . These brackets are configured to capture the cross-section of the bent bar portion  21 , while allowing pivoting of the pivoting extension flap member  30  relative to the bent bar portion  21 . Spring loading may be provided by use of a torsion spring [ 49 ] which winds about the lower portion of the bent bar portion  21  and has its radial engagement portions in contact with the brace and the flap. 
     It should be understood that the movable pivoting nature of the flap allows for the flap to be “directional”, in that it may be able to pass over certain obstacles in one (e.g. the forward) direction, but not in another (e.g., the reverse) direction. It should also be understood that other non-pivoting configurations are contemplated, such as sliding configurations. 
     Reference is now made to FIG. 2, which shows a notch  35  in the pivoting extension flap member  30 , which allows a trip lever  40 , described below in further detail, to pass therethrough when the pivoting extension flap member  30  pivots from its position shown in FIG.  3 A-FIG.  3 B. 
     In the configuration shown in FIG. 3B, the function of the notch  35  is evident, as in the  3 B configuration, the trip member  40  is positioned within the slot. This discourages tripping of the trip lever  40  when the extension flap member  30  is pivoted such as shown in FIG.  3 B. 
     As noted above, the reverse contact bar assembly  20  is pivotably mounted relative to the overall frame of the lawn mower apparatus  10 , and is spring-loaded into a particular position along its pivoting range. This springing is provided by a compression spring such as  27  shown in FIG.  8 . This compression spring is positioned between fixed flange  29  and a stop  28  of a reverse bar spring  27 . Other bias devices could also be used in place of the particular spring  27 . 
     The fixed flange  29 , shown in FIG. 8, is rigidly attached to the side of the frame  12  of the lawn mower  10  according to the present invention. The fixed flange  29  defines a hole therethrough. 
     The reverse bar spring rod  26 , shown in FIG. 8 includes a short end and a long end. The short end is configured to go into a hole in the medial portion of one of the brace members  22  and be retained therein by a cotter pin. The longer end of the rod  26  includes a stop member  28 , which is spaced apart from the free end of the long end. The free end of the long end of the rod  26  is smooth and blunt. 
     During assembly, the reverse bar spring  27  is passed over the free end of the long portion of the reverse bar spring rod  26 , and is kept there. The free end of the long portion of the reverse bar spring rod is passed through a hole in the fixed flange  29 , such that the spring  27  is captured between the fixed flange  29  and the stop portion  28  of the long end of the reverse spring rod. 
     When the short portion of the reverse bar spring rod is passed through the hole in the brace member  22  and retained therein, it may be understood that the spring  27  is in a position which facilitates its use as a compression spring. It may be understood that the selection of the strength and the properties of this compression spring  27  allow one (including the manufacturer) to select the amount of spring pressure required to cause the reverse contact bar assembly  20  to be pivoted as discussed below by contact with an object while the apparatus  10  is in reverse. 
     The spring  27  is preferably calibrated to prevent pivoting of the reverse contact bar assembly  20  if the user is backing up in heavy grass, but a single, more stable object such as a tree trunk or rock could cause pivoting. 
     Trip Member  40  (FIG. 4) 
     A trip member  40  is used to retain a slide member  50  in its retracted position until the trip member is “tripped” by the reverse contact bar assembly  20 . When the trip member  40  is tripped, it releases the slide member  50  such that the slide member  50  slides due to spring force by a tension spring as described in later detail. 
     Reference is now made to FIG. 4, which illustrates the trip member  40 . In this figure, the trip member  40  is shown in a relatively isolated position, in that the hardware which supports it in a pivoting relationship is not shown. However, it should be understood that hardware described later pivotably mounts the trip member  40  relative to the frame of the apparatus  10  by use of hole  43 . 
     The trip member  40  includes a lower cam end  42 , a hole  43 , and a latch member  46 . A torsion spring (shown in FIG. 7) is configured to maintain a torsional force on the trip member to provide a counterclockwise bias on the trip member about pivot point  44  as described later in this application. 
     The latch member  46  is configured to fit within a latch slot  52  of slide member  50 . When the trip member  40  is pivoted from its initial position as shown in FIG. 4 to its “tripped” position shown in FIG. 5, the trip member  40  has pivoted an angular amount in the direction of arrow “ 1 ” sufficient to withdraw the latch member  46  from the latch slot. As the slide member  50  is spring-loaded in the position of arrow “ 2 ” in FIG. 5, this causes the slide member  50  to move in the direction of arrow “ 2 ”. 
     As described later in this application, the above-referenced sliding movement of the slide member  50  is used to provide several functions for separate mechanical features. These features include braking and declutching. 
     Slide Member  50   
     As noted above, the slide member  50  is retained in a “set” position such as shown in FIG. 4, until released to slide under spring force to the “tripped” position shown in FIG.  5 . 
     Reference is now also made to FIG. 6 which illustrates the slide member  50  according to the present invention, in conjunction with a trip lever  40 , a clutch drag link  60 , a slide biasing spring  70  (shown in illustrative form), a brake cable  72 , and a reset cable  74 . 
     The slide member  50  includes a main body portion, a long upper flange  56 , and a short lower flange  57 . The slide member  50  could thus be thought of as having through much of its length a L-shaped transverse cross-section (defined by the main body portion and the long upper flange  56 ), while at one end having a additional short lower flange  57  which provides it with what could be referenced as a “J-shaped” transverse cross-section. 
     The long upper flange  56  defines an elongate latch slot  52 , and defines various holes which are configured to accept the return spring  70  and reset cable  74 . The short lower flange  57  is configured to accept the brake cable  72 . 
     It may be generally understood that the slide member  50  shown in FIG. 6 is slidably mounted relative to the frame of the cutting apparatus  10 . The direction of this sliding is generally along an axis parallel to the front-to-back orientation of the cutting apparatus  10 . The sliding direction is guided by use of the elongate guide slots in the main body portion  51  of the slide member  50 . These elongate slots are separately described as a leading guide slot  54 , and trailing guide slot  55 . As may be seen, these leading and trailing guide slots  54 ,  55  respectively, are positioned substantially along a common longitudinal axis which is substantially parallel to the longitudinal axis of the relative elongate slide member  50 . 
     The slide member  50  is acted upon by a significant spring force due to spring  70 . In one embodiment this spring force can approach 100 pounds, although obviously other forces may be provided as needed. Such a force is utilized under the present invention due to provide significant mechanical actions, such as braking and declutching. 
     It should also be understood that the slide member  50  can be retracted from its “tripped” position of FIG. 5 back to its “set” position of FIGS. 6 and 4 by use of reset lever  90  such as shown in FIG.  8 . This reset lever  90  will be discussed later in further detail, but in summary the reset lever  90  is configured to be manually pivoted by the user such that an intermediate cable  74  pulls the slide member  50  back to its position as shown in FIG.  4 . This allows the latch member  46  to re-engage the slot  52  of the slide member  50 , thus retaining the slide member  50  in its “set” position until the trip lever  40  is tripped again. It may be understood that such a retraction is done against the spring force associated with spring  70  discussed above. 
     As shown in FIG. 6, a brake cable  72  leads from the slide member  50  to a conventional brake apparatus. Thus as the brake cable is placed into tension as the slide moves right-to-left as FIG. 6 is viewed, the brake is applied. Upon reset of the slide member, the brake is released (unless otherwise depressed). 
     Clutch Drag Link Assembly  60  (FIGS. 6 and 9) 
     A drag link member  60  is used to provide a mechanical link between the slide member  50  and a clutch yoke member  86 , such that movement of the slide member  50  from its set to its tripped position causes the drive line to the drive wheels to be declutched at about the same time the apparatus is braked. 
     The clutch drag link assembly  60  includes an L-shaped rod portion and a tie rod end portion. The L-shaped rod portion is composed of a short leg and a long leg. The short leg has a cotter pin hole towards its free end and a stop spaced further away from the free end. The long leg has a threaded free end which threadably engages a tie rod end, which includes an internal ball joint and a threaded tie rod shaft portion threadably configured to threadably engage a nut. 
     A friction disk guide yoke  86  is configured to pivot about an axis  88  by use of a fastener (not shown) which passes through the yoke pivot hole  87 . The yoke  86  includes a yoke flange  85  rigidly extending therefrom. 
     The threaded tie rod shaft portion  68  passes through a hole in the yoke flange  85 , and is attached thereto by nut  69 . Thus the L-shaped portion of the drag link assembly  60  could be thought of as being attached to the yoke flange  85  by a ball joint. It may thus also be understood that movement of the short leg of the L-shaped portion of the drag link assembly  60  in the direction of the straight arrow in FIG. 9 causes rotation of the yoke around axis  88  in the direction of the curved arrow. Such rotation is similar to rotation of the yoke in its normal declutching movement as known in the art, and is not further described herein for purposes of brevity. However, any suitable declutching movement may be used under the present invention. 
     Additional information is now provided with reference to the interaction of the slide member  50  with the remainder of the apparatus  10 . As noted before, the slide member is configured to slide relative to the remainder of the apparatus along a linear guide path, and is guided along said path by use of a leading and trailing guide slots  54 ,  55 , respectively. The leading guide slot has only the short leg of the L-shaped portion  61  of the drag link assembly  60  passing through it, and is thus guided thereby. The short leg of the L-shaped portion  61  of the drag link assembly  60  also passes through another elongate slot in the frame of the apparatus (not shown), which is substantially co-extensive with the leading guide slot  54  when the slide member  50  is in its set position. This allows the clutch drag link to travel along both slots during operator clutching without affecting the slide member. 
     As noted before, the short leg of the L-shaped portion  61  of the drag link assembly  60  passes through slots in the slide member  50  and the frame of the apparatus. The slide member is slidably retained relative to the frame of the apparatus by the combination of the stop  65  and a cotter pin (not shown) which extends through the cotter pin hole  67 . 
     Bushing  80  and Attached Elements 
     Reference is now made to FIG. 7, which illustrates a guide bushing  80 , which is configured to be rigidly attached relative to the frame  12  of the apparatus by use of a threaded nut  84  and bolt  83 . The bolt passes through a hole in the frame  12 , the trailing guide slot of the slide member  50 , the bore of the bushing  80 , the hole  43  of the trip lever  40 , a flat washer  79 , and is captured by the nut  84 . A torsion spring  78  fits around the bushing  80  and is configured to maintain a torsional bias on the trip lever towards its “set” portion. 
     Thus the bushing  80  and the frame  12  combine to provide a sliding guide for the sliding action of the slide  50 , the bushing  80  and the flat washer combine to provide a rotating guide for the trip lever. 
     Reset Lever  90  (FIG. 8) 
     In order to reset the slide  50 , a reset lever  90  with a suitable reset cable  74  therebetween is configured to reset the device. FIG. 8 is an isolated view of a reset lever  90  according to the present invention. Reset cable  74  has one end attached relative to the reset lever  90  and the other end attached relative to the slide  50 . 
     The elongate handle member  90  is configured to be manually pivoted by a user and pivoted around the hole  94 . A second hole  93  is used to attach relative to one end of cable  74 . A return spring  91  can also have one end attached in hole  93  and the other end attached relative to the vehicle frame. 
     Other Options 
     It should be understood that, although the invention as shown in FIG. 1 includes the use of a contact bar assembly which is positioned in the rear of the apparatus, a similar assembly can be used towards the front of the apparatus as shown as  120  in FIG.  1 . Such an assembly could be positioned in front of the front wheels, such as might be understood as a “front bumper”-type configuration, or alternately such could be positioned as shown behind the front wheels. 
     This could be used on a riding lawn mower or alternate use as a garden tractor, or could also be used within various apparatuses such as known in the art. The “disabling device” which previously described declutching and/or braking could also be used to provide engine kill and/or blade stop as desired, upon the “tripping” of the reverse contact bar assembly. 
     If a vacuum system is used to control the blade, the vacuum could be disengaged to disengage the blade, is so desired. 
     Other Concepts 
     Other concepts may be mentioned at this time. A commercial walk-behind lawn mower according to another present invention which uses Eaton transaxles, the same as is used on the HomeOwner Zero Turn units, and dual oil reservoirs are used to prevent any cross contamination. These transaxles are mounted for horizontal input, the inventors are able to use a horizontal shaft engine that mounts directly over the axles. This provides excellent balance superior to other models in this category. 
     A horizontal shaft engine allows the inventors to use a quick connect automatic style universal joint drive shaft to propel the deck and the belt drive becomes the same as the trouble free drive of the Out Front and Mid Mount units. With the horizontal input, both the electric clutch belt and the transmission drive belt are easily replaceable. 
     The excellent balance afforded by this design allows the inventors to fold the handles forward and stand the entire mower up on its rear frame for service. This is also a first known for this category. 
     The invention can have larger front caster (11×4.00-5) and larger drive wheels (18×8.00-8) than other walk mowers in our line, and front caster brackets are replaceable. 
     The rear height of cut is an Acme thread screw jack arrangement that incorporates a rear guide rod that absorbs both impact and bending loads thus protecting the threaded adjusters. This provides easy deck adjustment and longer thread life. The bracket is notched to indicate height of cut settings to make it easy to set the same on both sides. The front height of cut is accomplished with the use of split spacers. The deck has a height of cut range from 1½″ to 4½″ and it is not necessary to move blade spacers. The deck attached to the rear frame with a heavy shoulder bolt connection. This pivot connection is secured with the use of two ⅜″ bolts and weld nuts. By removing these two ⅜″ bolts and disconnecting the quick connect end of the drive shaft from the power unit the deck will flip up for service and or storage. With the deck flipped up and the handles folded forward the unit takes up only 31 inches of trailer space. 
     The handle is attached with a quick connect lever that allows for easy release and dependable locking when the handle is folded or positioned for operation. 
     The power unit is 40 inches wide and the wheelbase is 42 inches. This essentially square design provides excellent stability and maneuverability. 
     The loop handle controls are easy to use and require less steering effort than conventional hydro units. They can operate the same as other prior art hydros and make use of a thumb latch neutral lock for starting and stopping. 
     A spring-loaded park brake/neutral control is located on the left side of the control panel. This automatic mechanism puts the transmissions in neutral and locks the internal transmission brakes any time the operating presence bale is released. If the blade is running when the bale is released the transmissions will go to neutral, the brakes will lock and the engine will kill stopping motion of machine and blades. 
     While this invention has been described in specific detail with reference to the disclosed embodiments, it will be understood that many variations and modifications may be effected within the spirit and scope of the invention as described in the appended claims.