Abstract:
This invention relates to a pivotal control for engaging and disengaging the parking brake of an outdoor power equipment unit such as a lawn mower. The control is laterally pivotal from an inboard to an outboard position by the operator as the operator mounts or dismounts the unit. This lateral pivoting motion is converted by a bevel gear arrangement to a longitudinal push on the inner cable of a Bowden cable, with the inner cable being connected to a parking brake. Pushing on the inner cable in this manner causes a portion of the inner cable between a fixed rear end of the outer sheath of the Bowden cable and the parking brake to become additionally curved or bowed. The amount of this additional curvature or bow is sufficient to develop a biasing force in the inner cable that keeps the parking brake engaged. Thus, no separate biasing spring is required.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to an outdoor power equipment unit, such as a lawn mower, having a parking brake actuated by a pivotal control. More particularly, this invention relates to the use of a flexible actuator cable to link the control to the parking brake to actuate the parking brake upon pivotal movement of the control. 
       BACKGROUND OF THE INVENTION 
       [0002]    When operating an outdoor power equipment unit such as a riding lawn mower, the operator frequently needs to dismount the unit. Most units of this type have a parking brake to prevent the unit from rolling away when the operator dismounts. A manually operated brake lever is usually provided to engage and disengage the parking brake. If the operator forgets to set or engage the parking brake as the operator dismounts, the unit can roll away if the unit is located on an incline when the operator dismounts. This is obviously undesirable. 
         [0003]    Similarly, the operator must also remember to disengage the parking brake when he remounts the unit to continue operating the unit. If the operator does not do so and the parking brake remains engaged, there is a potential for damaging the parking brake or drive train of the unit. At the very least, the parking brake and drive train experience undue wear if the unit is driven while the parking brake remains engaged. Thus, the operator must pay careful attention to the parking brake to make sure it is engaged when he dismounts and is disengaged after he remounts before he commences operation of the unit. 
         [0004]    Various riding lawn mowers are controlled by twin control sticks or handles that are selectively manipulated by the operator to propel and steer the unit. The control sticks have a neutral position in which the unit is at rest. To propel the unit forwardly, the sticks are pushed forwardly by the operator from the neutral position. To propel the unit rearwardly, the sticks are pulled rearwardly by the operator from the neutral position. Steering is accomplished by pushing or pulling on one stick more than the other or even by pushing one stick forwardly while pulling the other stick rearwardly. U.S. Pat. No. 3,702,051 to Deines shows a mower of this type. 
         [0005]    The twin control sticks of units of this type have an inboard position in front of the operator&#39;s seat where they are conveniently located in front of the operator&#39;s hands. However, in this position, the operator cannot easily reach the seat for mounting and dismounting as the control sticks obstruct access to the seat. Thus, such control sticks are also pivotal about longitudinal, fore-and-aft axes to allow the sticks to be pivoted laterally into outboard positions. In their outboard positions, the control sticks do not obstruct the operator&#39;s access to the seat. 
         [0006]    Accordingly, to dismount the unit, a seated operator first pivots the control sticks laterally into their outboard positions to clear the way for dismounting. To remount the unit, the operator first climbs back onto the seat by passing between the control sticks when such control sticks are disposed in their outboard positions. After the operator is reseated, the operator can then pivot the control sticks from their outboard positions back into their inboard positions until the control sticks are located generally in front of the operator as the operator sits on the seat. The fact that the control sticks in a twin stick unit of this type laterally pivot between inboard and outboard positions to allow mounting and dismounting is well known in the mower art. 
         [0007]    U.S. Pat. No. 6,434,917 to Bartel shows a twin stick mower in which the control sticks are linked by mechanical linkages to a parking brake comprising a pair of parking brakes, one for each drive train controlled by each control stick. In Bartel, the mechanical linkages are elongated and extend vertically to connect between the parking brakes and the control sticks. Moreover, the linkages include ball joints to accommodate the lateral pivoting of the control sticks when the control sticks are placed in their outboard positions. Thus, the mechanical linkages are relatively cumbersome and are located in an area of the mower where space is tight. 
         [0008]    The Toro Company, the assignee of this invention, has built and sold a mower, such as the TimeCutter Z380, that is similar to the mower disclosed in the 917 patent, namely a mower having twin control sticks that engage parking brakes when the control sticks are laterally pivoted to outboard positions. In this prior art Toro mower, the control sticks pivot about two orthogonal pivot axes rather than using ball joints. An actuator carries each control stick with the actuator pivoting on the frame of the mower about a transverse, lateral pivot axis. This allows the control stick to be longitudinally pushed forwardly or pulled rearwardly to longitudinally pivot the control stick to propel the mower forwardly or rearwardly. In addition, the control stick further pivots on the actuator itself about a longitudinal, fore and aft pivot axis to allow the control stick to be swung or pivoted laterally between the inboard and outboard positions thereof. This lateral pivoting of the control stick on the actuator is what engages or disengages the parking brake. 
         [0009]    In this prior art Toro mower noted above, the control stick is connected by a fairly complicated mechanical linkage to the parking brake. The lateral pivoting of the control stick has to be converted to a longitudinal motion of a connecting rod. The connecting rod extends rearwardly from the control stick to the parking brake. Rearwardly moving or sliding the connecting rod when the control stick pivots laterally outwardly engages the parking brake. 
         [0010]    In this prior art Toro mower, this motion conversion is done by three distinct components: a first link carried on the control stick, a vertical connector that gets lifted when the first link is pivoted by laterally outward motion of the control stick, and a bell crank that pivots on a lateral pivot axis. One arm of the bell crank is connected to the vertical connector so that the bell crank gets rotated about the lateral pivot axis when the vertical connector is lifted. The other arm of the bell crank is connected to the front end of the connecting rod to push rearwardly on the connecting rod when the bell crank is pivoted. Thus, three separate parts and the space needed to accommodate such parts are required, namely the first link, the vertical connector, and the bell crank, just to translate the laterally outward pivoting of the control stick to a rearward push on the connecting rod that leads to the parking brake. This is in addition to the rearwardly extending connecting rod itself, which comprises a fourth part. 
         [0011]    In addition, the parking brake must be positively engaged when the parking brake is actuated by the connecting rod. In the existing Toro mower design described above, this is done using a spring surrounding a portion of the rearwardly extending connecting rod. The spring supplies a positive biasing force that keeps the parking brake engaged when the control stick has been pivoted laterally outwardly. Thus, the spring comprises yet another component or part, i.e. a fifth part, in this prior art design. The need for this number of components obviously increases the cost and complexity of the mower. A simpler and more cost effective design is desirable. 
       SUMMARY OF THE INVENTION 
       [0012]    One aspect of this invention relates to an outdoor power equipment unit which comprises a frame supported for movement over the ground by a plurality of wheels. At least one wheel is a drive wheel to propel the frame over the ground. An implement is carried on the frame for performing a ground or turf grooming or working operation. A parking brake is provided. A control is selectively movable by an operator of the unit for engaging and disengaging the parking brake. The control is operatively coupled to the parking brake by a flexible actuator cable. The actuator cable is arranged relative to the control and to the parking brake such that a portion of the actuator cable becomes additionally curved or bowed when the control is moved to engage the parking brake with the additional curvature or bow in the actuator cable being sufficient to exert a biasing force on the parking brake tending to keep the parking brake engaged. 
         [0013]    Another aspect of this invention relates to an outdoor power equipment unit which comprises a frame supported for movement over the ground by a plurality of wheels. At least one wheel is a drive wheel to propel the frame over the ground. An implement is carried on the frame for performing a ground or turf grooming or working operation. A parking brake is provided. A control is selectively movable by an operator of the unit for engaging and disengaging the parking brake. The control is pivotally carried on the frame of the unit for lateral movement relative to the unit between an inboard position located in front of an operator&#39;s seat and an outboard position located to one side of the operator&#39;s seat to permit the operator to mount and dismount the unit. A linkage couples the control to the parking brake. A bevel gear arrangement converts laterally outward pivoting of the control between the inboard and outboard positions thereof into longitudinal movement of at least a portion of the linkage relative to the frame to engage the parking brake. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    This invention will be described more completely in the following Detailed Description, when taken in conjunction with the following drawings, in which like reference numerals refer to like elements throughout. 
           [0015]      FIG. 1  is a perspective view of an outdoor power equipment unit equipped with a control according to this invention for actuating a parking brake; 
           [0016]      FIG. 2  is an enlarged perspective view of a portion of the unit of  FIG. 1 , particularly showing the control and the cable linkage leading from the control to the parking brake; 
           [0017]      FIG. 3  is a side elevational view of a portion of the unit of  FIG. 1 , particularly showing a portion of the cable linkage used to actuate the parking brake and the connection of such linkage to the parking brake; 
           [0018]      FIG. 4  is a side elevational view of a portion of the unit of  FIG. 1 , particularly showing a portion of the cable linkage used to actuate the parking brake and the connection of such linkage to the control; and 
           [0019]      FIG. 5  is a side elevational view of a portion of the unit of  FIG. 1 , particularly showing the lower end of the control and the bevel gear used to convert the laterally outward pivoting motion of the control to a longitudinal actuation of the cable linkage. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  illustrates an outdoor power equipment unit  2  comprising a riding mower. Unit  2  includes a frame  4  supported for movement over the ground by a pair of front caster wheels  6  and a pair of rear drive Wheels  8 . A seat  10  is provided on frame  4  for supporting a seated operator. An internal combustion engine or the like (not shown) is provided on the rear of frame  4  behind seat  10  to power unit  2 . A cutting deck  12  is mounted underneath frame  4  between front caster wheels  6  and rear drive wheels  8  for mowing grass or the like. 
         [0021]    Unit  2  includes two control sticks  14  for allowing the operator to cause unit  2  to move in forward and reverse and to steer unit  2 . Each control stick  14  controls an independent hydrostatic transmission or transaxle  16  that drives one of the rear drive wheels  8  in a known manner. The internal combustion engine powers each transaxle  16  as well as cutting deck  12 . Each transaxle  16  can be operated separately from the other and at different speeds by its corresponding control stick  14  to achieve both propulsion and steering of unit  2 . 
         [0022]    As shown in  FIG. 1 , each control stick  14  has an inboard position in which the top of control stick  14  is located in front of the operator as the operator sits on seat  10 . Each control stick  14  also has a laterally pivoted, outboard position in which control stick  14  has been pivoted to one side largely out of the way of seat  10  to permit the operator to more easily mount and dismount seat  10 . Normally, both control sticks  14  are usually disposed in the same position, i.e. both control, sticks  14  are either in their inboard positions or in their laterally pivoted, outboard positions at the same time, though it is physically possible to have one stick  14  in one position and the other stick  14  in the other position. 
         [0023]    Unit  2  also includes a parking brake system  18  for preventing unit  2  from rolling when it is parked. Because unit  2  includes two independent transaxles  16  for powering the two drive wheels  8 , parking brake system  18  includes two independent parking brakes  20 , one for each transaxle  16 . Parking brakes  20  are in the form of toothed pawls. 
         [0024]    Referring now to  FIG. 3 , each parking brake  20  is pivotally mounted on the housing of a transaxle  16  by a pivot pin  22 . Each parking brake  20  has teeth  24  for meshing with an external gear or sprocket  26  of transaxle  16 . When the parking brake  20  is pivoted into meshing engagement with gear  26  as shown in  FIG. 3 , transaxle  16  is locked up to prevent transaxle  16  from rotating to thereby lock the corresponding drive wheel  8 . When the parking brake  20  is pivoted out of meshing engagement with gear  26 , transaxle  16  and its associated drive wheel  8  are both free to rotate. 
         [0025]    While the use of a parking brake system  18  comprising two independent parking brakes  20  has been illustrated, it would be possible to have a parking brake system  18  which deletes one of the two parking brakes  20 . Locking up a single transaxle  16  and its associated drive wheel  8  should be sufficient to prevent unit  2  from rolling. However, it is preferred to use dual parking brakes  20  when dual independent transaxles  16  are used. Thus, the number of parking brakes  20  within parking brake system  18  can obviously be varied as long as there is at least one such parking brake  20 . 
         [0026]    In addition, parking brakes  20  that are mechanically different from pivotal pawl type parking brakes engaging a gear on a transaxle could also be used. This is particularly true where the drive wheels  8  are driven by some type of drive system other than that shown herein. Thus, the nature of the parking brake(s) used within parking brake system  18  can also be varied. The phrase “parking brake system” as used herein is simply meant to apply to any system that has at least one parking brake for holding unit  2  stationary when it is parked with such parking brake having both an engaged and disengaged position. 
         [0027]    Each parking brake  20  is engaged and disengaged by one control stick  14 . The linkage that does this is identical for each control stick  14  and its corresponding parking brake  20 . Thus, the linkage extending between only one control stick  14  and its corresponding parking brake  20  need be specifically described. That linkage will now be described in conjunction with  FIGS. 2-5 . 
         [0028]    A pivotal actuator  30  is carried on frame  4  of unit  2  for pivotal movement about a lateral pivot axis  32  formed by pivot pin  33 . Control stick  14  is carried with and supported by pivotal actuator  30 . Thus, as the operator pushes forwardly on control stick  14  to cause forward motion of unit  2 , control stick  14  pivots forwardly about lateral pivot axis  32  as indicated by the arrow A in  FIG. 5 . Conversely, if the operator pulls rearwardly on control stick  14  to cause reverse motion of unit  2 , control stick  14  pivots rearwardly about lateral pivot axis  32  as indicated by the arrow B in  FIG. 5 . Forward and reverse motion is accomplished since the bottom of actuator  30  is linked by a mechanical connecting rod  34  to a direction and speed change mechanism on the hydrostatic transmission  16  that drives rear wheel  8  on the corresponding side of unit  2 . 
         [0029]    While control stick  14  moves with actuator  30  for longitudinal pivoting motion in the direction of the arrows A and B in  FIG. 2 , control stick  14  is also independently mounted on actuator  30  for lateral pivoting motion of control stick  14  relative to actuator  30 . Thus, the lower end  42  of each control stick has a bore  38  that is pivotally journalled on a longitudinal pivot pin  36  defining a longitudinal pivot axis. Pivot pin  36  has been removed in  FIG. 5  to better illustrate bore  38 , but pivot pin  36  is shown in  FIG. 4  passing through lower end  42  of control stick  14 . Thus, because of longitudinal pivot pin  36 , control stick  14  is enabled to laterally pivot between the inboard and outboard positions thereof as described above. 
         [0030]    Actuator  30  also carries a bevel gear  44  that is mounted for rotation on a vertical pivot axis  46 . Bevel gear  44  is placed immediately forward of lower end  42  of control stick  14 . The teeth of bevel gear  44  are in engagement with teeth on a mating sector gear  48  that is formed as an integral part of lower end  42  of control stick  14 . Because control stick  14  has only a limited angular range through which it laterally pivots, sector gear  48  on lower end  42  of control stick  14  extends only along an arcuate portion of a circle and is not a full 360° gear. When control stick  14  is pivoted laterally outwardly about the longitudinal pivot axis, the engagement of sector gear  48  and bevel gear  44  causes bevel gear  44  to rotate a similar angular amount about its vertical pivot axis. 
         [0031]    Bevel gear  44  has a laterally extending, horizontal attachment ear  50 . Ear  50  contains an attachment hole  52  at its outer end thereof. Hole  52  is sized to allow an inner cable  54  of a flexible Bowden cable  56  to be connected thereto. The front end of inner cable  54  of Bowden cable  56  has a hook configuration  58  allowing the front end of inner cable  54  to be slipped up into and retained in hole  52  on the ear  50  of bevel gear  44 . Hook  58  is shown in  FIGS. 4 and 5  as being disconnected from hole  42  for the purpose of clarity. When bevel gear  44  rotates by virtue of the lateral pivoting motion of control stick  14 , inner cable  54  is longitudinally pulled or pushed depending upon the direction of rotation of bevel gear  44 . 
         [0032]    As is typical in Bowden cables  56 , inner cable  54  slides within an outer sheath  59 . Outer sheath  59  is clamped to various portions of unit  2 . The front end of outer sheath  59  is clamped by a bracket  60  to pivotal actuator  30  just rearwardly of lateral pivot axis  32 . See  FIGS. 3-5 . The rear end of outer sheath  59  is clamped to a bracket  62  that is part of frame  4  of unit  2 . See  FIGS. 3 and 4 . 
         [0033]    Referring to  FIG. 3 , the rear end of inner cable  54  extends for some distance out of outer sheath  59  and connects to parking brake  20 . When inner cable  54  is slid forwardly from the orientation shown in  FIG. 3 , it lifts on a rearwardly extending arm  21  of parking brake  20  to pivot parking brake  20  in the direction of the arrow C about pivot pin  22 . This will pivot parking brake  20  out of engagement with gear  26  to release parking brake  20 . Inner cable  54  is slid forwardly in this manner when control stick  14  is disposed in its laterally inboard position. 
         [0034]    However, when the operator pivots control stick  14  to its laterally outboard position to clear the space in front of the operator&#39;s seat to allow the operator to dismount, bevel gear  44  is rotated in a direction that pushes rearwardly on the front end of inner cable  54 . As the front end of inner cable  54  is pushed rearwardly, the rear portion of inner cable  54  gets pushed further out of the fixed rear end of outer sheath  59  which is clamped to bracket  62 . In other words a larger length of inner cable has to be accommodated in the space between parking brake  20  and the spatially fixed bracket  62 . 
         [0035]    This motion of the rear portion of inner cable  54  does two things. First, it pushes down on arm  21  of parking brake  20  to pivot parking brake  20  into its engaged position as shown by the arrow D in  FIG. 3 . In this position as shown in  FIG. 2 , the teeth  24  of parking brake  20  mesh with gear  26 . In addition, inner cable  54  of Bowden cable  56  is forced to bend or become more curved in order to accommodate the additional length of wire between parking brake  20  and the rear end of outer sheath  59 . In fact, this bend is designed to be large enough so that inner cable  54  of Bowden cable  56  actually develops a biasing force on parking brake  20  tending to keep parking brake  20  engaged. In effect, inner cable  54  of Bowden cable  56  becomes a spring that helps ensure that parking brake  20  remains meshed with gear  26 . 
         [0036]    Accordingly, this invention is a much simpler and more cost effective solution than prior art designs for coupling the laterally pivotal control stick  14  to parking brake  20 . It uses far fewer parts than prior art designs. It also totally obviates the need for a separate retention spring since inner cable  54  of Bowden cable  56  itself becomes the spring when parking brake  20  is engaged. 
         [0037]    Various modifications of this invention will be apparent to those skilled in the art. Thus, the scope of the invention shall be limited only by the appended claims.