Abstract:
A control system for a BBC on a mower comprises a pivotal bail and a pivotal housing that is linked to the BBC. If a push member on the housing is pushed inwardly from the side of the housing before the bail is pivoted, then a pin moves to a blocking position behind the bail. Subsequent pivoting of the bail will pivot the housing to actuate the BBC. A channel in the housing frictionally grips the bail to prevent rebound of the bail when a spring force resets the housing and the bail to their initial positions after the operator releases the bail. Movement of the push member also closes an interlock switch which will kill operation of the engine if a grass discharge outlet on the mower is un-covered.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to a control system for actuating a component of an outdoor power equipment unit, such as a blade brake clutch on a mower. More particularly, this invention relates to a control system that requires two distinct operator actions before the component is actuated.  
       BACKGROUND OF THE INVENTION  
       [0002]     Powered rotary lawn mowers are in wide use by consumers for cutting grass. Such rotary lawn mowers have a housing that encloses a sharpened cutting blade that rotates in a substantially horizontal cutting plane. A handle extends upwardly and rearwardly from the housing to allow an operator to walk behind the housing and to guide the housing during operation of the mower. The housing carries a prime mover, such as an electric motor or internal combustion engine, for rotating the cutting blade. A safety standard that is applicable to consumer lawn mowers requires that the blade come to a stop if the operator releases the handle. In addition, rotation of the blade can be initiated only if the operator performs two distinct actions. Manufacturers of such equipment have offered two major types of mowers that meet these requirements. These mowers comprise zone start mowers and blade brake clutch (BBC) mowers.  
         [0003]     In a BBC mower equipped with an internal combustion engine, the engine can be started in a generally conventional manner, using either a rope pull or an electric starter. Once the engine is started, the engine remains running during the operation of the lawn mower unless the engine is purposely shut off by the operator. This is true even if the operator releases the control bail carried on the handle.  
         [0004]     In a BBC mower, once the operator releases the control bail, a clutch between the blade and the output shaft of the engine is released and a blade brake is engaged. Thus, even though the engine continues to run, the blade comes to a stop. This can be contrasted with a zone start mower in which the blade comes to a stop once the control bail is released since the engine is killed, i.e. engine ignition is disrupted. Nonetheless, the result is the same in both cases, namely the blade comes to a stop when the operator releases the control bail.  
         [0005]     However, in a BBC mower, the control bail must operate differently than in a zone start mower due to the need for two separate operator actions to reengage operation of the blade. In a zone start mower, the first action is the required restarting of the engine. The second action is the closing of the control bail against the crossbar of the handle.  
         [0006]     But, in a BBC mower, restarting of the engine cannot be used as the first action since the engine remains running. Thus, the mower must be equipped with some type of additional control that must be actuated before the closure of the control bail is effective to start rotation of the blade. This additional control approach is shown in U.S. Pat. No. 5,784,868 to Wadzinski. Alternatively, the bail can have some type of multi-directional movement before the closure of the control bail places the blade back into operation, as disclosed in U.S. Pat. No. 4,327,539 to Bricko.  
         [0007]     The control system used in a BBC mower to start and stop the rotation of the blade is necessarily more complex than that in a zone start mower. Generally speaking, such a BBC control system is not as intuitively obvious to use as that for a zone start mower. Accordingly, there is a need in the art for a BBC control system that is simple and relatively easy to understand and use.  
       SUMMARY OF THE INVENTION  
       [0008]     One aspect of this invention relates to a control system for a component of an outdoor power equipment unit, the outdoor power equipment unit having a handle that includes a crossbar. The control system comprises a control member movably mounted to the handle. The control member being is movable back and forth on the handle in a predetermined path of motion. The control member is movable away from the crossbar into a disengaged position in which the control member is spaced from the crossbar and is movable towards the crossbar into an engaged position in which the control member is adjacent the crossbar. A housing is movably mounted to the handle. The housing is operatively linked to the component to engage the component when the housing is moved towards the crossbar. A push member is movably carried on the housing for sideward motion from a first lateral position on the housing to a second lateral position on the housing, the first and second lateral positions being laterally displaced from one another on the housing. A blocking member is carried on the push member. The blocking member is laterally clear of the path of motion of the control member when the push member is in the first lateral position thereof. The blocking member extends laterally into the path of motion of the control member when the push member is in the second lateral position thereof. Thus, motion of the control member towards the crossbar is linked to the housing through the blocking member on the push member such that the housing is also moved towards the crossbar to engage the component only if the push member is first pushed to the side between the lateral first and second positions thereof before the control member is moved between its disengaged and engaged positions.  
         [0009]     Another aspect of this invention relates to a control system for actuating a component of an outdoor power equipment unit. The control system comprises a control member pivotally mounted on a handle of the outdoor power equipment unit. The control member is pivotal between a component disengaged position and a component engaged position. A housing is pivotally mounted on the handle, the housing being configured to be selectively disposed in a first position in which the housing is not pivoted by movement of the control member and a second position in which the housing is pivoted by movement of the control member. The housing is connected to the component to actuate the component when the housing is disposed in the second position and the control member is pivoted to its component engaged position. A switch is provided that changes state when the housing is disposed in the second position thereof, the change of state of the switch serving to stop operation of the component if a safety condition on the outdoor power equipment unit is not met.  
         [0010]     Yet another aspect of this invention relates to a control system for a component of an outdoor power equipment unit. The control system comprises a pivotal housing and a pivotal control member that is able to indepently pivot relative to the housing. A cable connects the pivotal housing to the component for actuating the component when the pivotal housing is pivoted in one direction by pivotal motion of the control member in the one direction. A spring force is applied to the cable in a direction tending to pivot the housing oppositely to the one direction. A retainer is provided on the housing for frictionally retaining the control member in the housing to prevent rebound of the control member out of the housing when the spring force resets the housing and the control member to an initial position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     This invention will be described hereafter in the Detailed Description, taken in conjunction with the following drawings, in which like reference numerals refer to like elements or parts throughout.  
         [0012]      FIG. 1  is a perspective view of a lawn mower equipped with the control system of this invention;  
         [0013]      FIG. 2  is an enlarged perspective view of the control system shown in  FIG. 1 , particularly illustrating the control system in a component disengaged position with the control bail being rotated away from and spaced from the crossbar of the handle;  
         [0014]      FIG. 3  is an enlarged perspective view similar to  FIG. 2 , but particularly illustrating the control system in a component engaged position with the control bail being rotated towards and held against the crossbar of the handle;  
         [0015]      FIG. 4  is a perspective view from above the control bail of the control system shown in  FIG. 1 , particularly illustrating the component disengaged position of the control system with the finger actuated push member being pivoted outwardly to its laterally outer, non-blocking position;  
         [0016]      FIG. 5  is a cross-sectional view through the control system shown in  FIG. 1 , particularly illustrating the component disengaged position of the control system with the finger actuated push member being pivoted outwardly to its laterally outer, non-blocking position;  
         [0017]      FIG. 6  is a perspective view from behind the control bail of the control system shown in  FIG. 1 , particularly illustrating the finger actuated push member being pivoted inwardly to its laterally inner, blocking position;  
         [0018]      FIG. 7  is a cross-sectional view similar to  FIG. 5 , but particularly illustrating the finger actuated push member being pivoted inwardly to its laterally inner, blocking position; and  
         [0019]      FIG. 8  is a cross-sectional view through the control system shown in  FIG. 1 , particularly illustrating the interaction between the finger actuated push member and a discharge interlock switch. 
     
    
     DETAILED DESCRIPTION  
       [0020]     Referring to  FIG. 1 , a typical rotary lawn mower is illustrated for background purposes generally as  2 . Mower  2  has a cutting deck  4  supported for movement over the ground by a plurality of wheels  6  or the like. A prime mover, such as but not limited to an internal combustion engine  8 , is provided on cutting deck  4  for rotating a cutting blade (not shown) that is housed within cutting deck  4 . An upwardly and rearwardly extending handle  10  includes a transverse upper crossbar  12  that is gripped by the operator to guide and operate mower  2 .  
         [0021]     This invention relates to a control system, illustrated generally as  14 , for engaging and disengaging a blade brake clutch (BBC) located between the cutting blade and engine  8 . The BBC is not shown in  FIG. 1  and may take any conventional design. When the BBC is engaged, the cutting blade is clutched to engine  8  and a blade brake is disengaged to permit the cutting blade to rotate. When the BBC is disengaged, the cutting blade is unclutched from engine  8  and the blade brake is engaged to stop the cutting blade from rotating. The purpose of control system  14  of this invention is to change the state of the BBC, i.e. to move the BBC from its disengaged state to its engaged state or vise versa.  
         [0022]     While control system  14  will be described in conjunction with a mower  2  for actuating a BBC, control system  14  could be used with other types of outdoor power equipment units, such as snowthrowers, for actuating a different component, such as the snowthrowing impeller. Thus, control system  14  is not limited for use with a mower or for actuating a BBC.  
         [0023]     One embodiment of a control system  14  according to this invention includes a control member in the form of a U-shaped bail  16 . Bail  16  is carried at the top of handle  10  adjacent crossbar  12 . Bail  16  has a pair of laterally spaced, downwardly extending legs  18  that are pivotally mounted along aligned transverse pivot pins  20  to the inside of a pair of handle tubes  22  of handle  10  . One transverse pivot pin  20  is shown in  FIG. 2 . The other transverse pivot pin  20  is hidden from view in  FIG. 2  but is shown in  FIG. 6 .  
         [0024]     Bail  16  is pivotal about the axis of pivot pins  20  from a first disengaged position as shown in  FIG. 2 . In this position, bail  16  is rotated forwardly away from crossbar  12  of handle  10 . However, bail  16  can be rotated rearwardly towards crossbar  12  of handle  10 , as shown by the arrow A in  FIG. 2 , until bail  16  generally abuts or lies against crossbar  12  of handle  10 . This is the engaged position of bail  16  as shown in  FIG. 3 .  
         [0025]     A pivotal housing  24  is mounted on one of the pivot pins  20  that mounts bail  16  to handle  10 . Thus, housing  24  is also pivotal about the same pivot axis around which bail  16  pivots. However, housing  24  is pivotal independently of bail  16 . While housing  24  and bail  16  can pivot together as will be explained hereafter, bail  16  can also pivot without pivoting housing  24 .  
         [0026]     Housing  24  includes an outer side that faces outwardly relative to handle  10  and is located above handle tube  22  on which housing  24  is pivotally mounted. The outer side of housing  24  has a push member  26  that is pivotally received in an alcove  28  on the outer side of housing  24 . Push member  26  is pivotal relative to housing  24  about a longitudinal pivot pin  30 , namely a pivot pin  30  extending fore and aft rather than transversely. Thus, push member  26  can be pivoted inwardly from the outer side of housing  24  against a spring force that will be described hereafter.  
         [0027]     Push member  26  can have any convenient shape. As shown herein, push member  26  is somewhat rectangular conforming to the general shape of alcove  28  in which push member  26  is received. Push member  26  has an arrowhead shaped, recessed portion  32  extending to the rear of push member  26 . Recessed portion  32  has a roughened or textured surface compared to the rest of push member  26 . The operator can insert a couple of fingers, namely the operator&#39;s index finger and middle finger, into recessed portion  32  of push member  26  to push inwardly on push member  26  from the side. Such an inward push from the side is illustrated by the direction of the arrow B in  FIG. 5 .  
         [0028]     The rear of housing  24  includes a rearwardly facing channel  34  that extends between the top and bottom of housing  24 . Channel  34  is wide enough to allow the adjacent leg  18  of bail  16  is be received within channel  34  when bail  16  is in its disengaged position. Desirably, one of the side walls of housing  24  forming channel  34  is angled or inclined somewhat inwardly such that bail  16  is received in channel  34  with an interference fit. The purpose for this will be described later.  
         [0029]     The backside of push member  26  has an inwardly extending pin  36  carried thereon. When push member  26  has not been pushed inwardly on the side of housing  24  but is biased to its laterally outer position as shown in  FIG. 5 , pin  36  clears channel  34  in which leg  18  of bail  16  is received. However, if the operator pushes push member  26  inwardly in the direction of the arrow B in  FIG. 5 , this will pivot push member  26  inwardly until push member  26  is now in a laterally inner, generally vertical position within alcove  28 . In this position of push member  26  as shown in  FIG. 6 , pin  36  has moved into a blocking position in channel  34  behind or to the rear of leg  18  of bail  16 .  
         [0030]     The two actions required to actuate the BBC and to begin operation of the cutting blade comprise pushing inwardly on push member  26  using the fingers of one hand followed by then pivoting bail  16  rearwardly from the disengaged position shown in  FIG. 2  to the engaged position shown in  FIG. 3 . If these two actions are performed in this sequence, then pin  36  will block off channel  34  in which the leg of bail  16  is received so that the pivoting motion of bail  16  will also pivot housing  24  as shown in  FIG. 3 . In effect, pin  36  temporarily joins housing  24  to bail  16  for conjoint rotation therewith.  
         [0031]     A control cable  38 , a portion of which is shown in  FIG. 4 , operatively connects housing  24  to the BBC. When housing  24  is pivoted with bail  16  as described above, the pivoting motion of housing  24  will pull rearwardly on control cable  38  to engage the BBC to cause blade rotation. When the operator releases bail  16  from its engaged position, the forward spring force normally present on control cable  38  will bias housing  24  and bail  16  back to the disengaged positions thereof shown in  FIG. 2 . This forward spring force is represented by the arrow C in  FIG. 4 .  
         [0032]     In this regard, the interference press fit between channel  34  and leg  18  of bail  16  is used to prevent a rebound action of bail  16  out of housing  24  during the return motion of housing  24  and bail  16 . The interference press fit is strong enough to provide a frictional gripping force on bail  16  that retains bail  16  within channel  34 . Without such a frictional gripping force, the Applicants discovered that bail  16  would rebound rearwardly towards crossbar  12  when housing  24  returns to the position shown in  FIG. 2 . Such rebound would be strong enough to cause bail  16  to potentially snap back against the operator&#39;s fingers as the operator grips crossbar  12 . This is prevented by the interference fit between channel  34  and leg  18  of bail  16 . While the interference press fit could be dispensed with if so desired, its use is preferred.  
         [0033]     Control system  14  disclosed herein is simple and intuitive to use. To engage the BBC, all the operator must do is push in on push member  26  and close bail  16  against crossbar  12  of handle  10 . Push member  26  includes a finger receiving, recessed portion  30  that invites the operator to place his or her fingers there and to push inwardly. To emphasize the separate nature of push member  26 , push member  26  and housing  24  in which it is received are made from differently colored plastic material, push member  26  being bright green and housing  24  being black for example.  
         [0034]     In addition, if the operator simply pivots bail  16  without first pushing in on push member  26 , the only thing that will happen is that bail  16  will slip out of channel  34  and become limp or untensioned. There is no direct spring force on bail  16 . The only spring force acting on bail  16  is the spring force present on housing  24  from the spring force acting on control cable  38 . Thus, as soon as the operator pulls bail  16  out of channel  34  and notices that there is no spring pressure acting on bail  16 , the operator will know that something more need be done in order to actuate the BBC. The operator will quickly and intuitively figure out that bail  16  must be reset into channel  34  and that push member  26  must be pushed laterally inwardly before closing bail  16 .  
         [0035]     Another enhancement that is possible with control system  14  of this invention is the use of a discharge interlock switch  40  in housing  24 . Interlock switch  40  is mounted in the forward part of housing  24  behind push member  26 . As shown in  FIG. 8 , interlock switch  40  is a conventional electrical normally closed switch having a spring biased actuating plunger  42 . Push member  26  has a switch actuating tab  44  in abutting engagement with switch plunger  42  as shown in  FIG. 8 . In fact, it is the outward bias of the spring contained inside interlock switch  40  acting on switch plunger  42  that provides the spring force that biases push member  26  into its laterally outer position in alcove  28  in housing  24 . If interlock switch  40  were not used, then a separate spring would be needed to bias push member  26  outwardly to the side of housing  24 .  
         [0036]     Interlock switch  40  works in conjunction with a discharge outlet switch (not shown) located at the discharge outlet  50  of mower  2 . If the discharge outlet switch does not detect the presence of either a bagging attachment  52  or a grass discharge chute or a mulch plug covering the rear discharge opening, then engine  8  will kill if push member  26  is pushed inwardly to actuate the BBC. Thus, if interlock switch  40  is opened by the inward movement of push member  26 , engine  8  will continue to run only if the discharge outlet switch detects the presence of some device covering the discharge outlet opening. If the discharge outlet switch detects that the discharge outlet opening is uncovered when interlock switch  40  is opened, then engine  8  will kill even though this is a BBC equipped mower. This nullifies the engagement of the BBC to prevent the operation of the blade if the discharge outlet  50  is unobstructed.  
         [0037]     Including interlock switch  40  as part of control system  14  is relatively simple and easy to do. It involves the simple addition of an electrical switch  40  into housing  24  that is already provided as part of control system  14 . In addition, it uses the spring inside the switch to provide the spring force needed to bias push member  26  to its usual laterally outer position, thus obviating the need for a separate spring to do this. Yet, it provides another desirable feature in that it will not allow the operator to mow if either the bagging attachment, grass discharge chute or mulch plug is not properly secured to discharge opening  50 . However, interlock switch  40  could be deleted if so desired without diminishing the other useful features of control system  14  of this invention, i.e. the simple intuitive use of control system  14  arising from push member  26 .  
         [0038]     Various modifications of this invention will be apparent to those skilled in the art. Thus, the scope of this invention is to be limited only by the appended claims.