Abstract:
Drive assemblies and related methods are provided particularly suited for a snowblower. The drive assemblies include a transmission wheel disposed about a shaft and rotatably movable for rotating at least one wheel. The transmission wheel has a contact surface. The drive assemblies also include a drive pulley having a drive surface. The drive pulley is rotatable and configured for causing the transmission wheel to rotate when the drive surface and the contact surface of the transmission wheel are in contact. At least one brake clutch is disposed about an end of the shaft to provide independent control to the at least one wheel.

Description:
TECHNICAL FIELD 
     The subject matter described herein relates generally to drive assemblies. More particularly, the subject matter disclosed herein relates to drive assemblies and methods for power equipment, particularly suitable for a snowblower to permit independent control of both wheels of a snowblower to turn the snowblower during operation. 
     BACKGROUND 
     Due to the depth of the snow in which snowblowers are usually used, many snowblowers are self-propelled. Snowblowers can be hard to manipulate within deep snow because of the weight of the machinery. The deeper the snow is, the harder it can be to maneuver the snowblower. Self-propelled snowblowers allow advancement and regression of the snowblower at least partially under the power generated by its engine. Self-propelled snowblowers can be relatively easy to use as compared to non-self-propelled snowblowers. Through the use of self-propelled mechanisms on snowblowers, a user can devote relatively less energy in advancing the snowblower forward and concentrate more energy on steering. 
     Typically, self-propelled snowblowers have an engine, a pair of drive wheels, an auger, and a discharge chute. The engine provides power to all power-requiring components of the snowblower, which include the drive wheels and the auger. A typical method used to transfer power from the engine to the wheels is using a friction drive or a chain drive. For either the chain drive or the friction drive, a user can engage the drive by, for example, depressing a drive lever located on the handlebar of the snowblower. 
     To turn the snowblower when the self-propelled drive of the snowblower is activated, the speed of rotation of the individual wheels can be changed. For example, the use of two clutches, one associated with each wheel of a two wheel snowblower, can be selectively operated by a pivoting control on the handle so as to allow for power steering of the snowblower. The drive system of such a snowblower can include an engine, a snowblower clutch, a drive clutch, and a final drive including two independent wheel clutches. The final drive can have left and right wheel clutches intermediate an input gear and the left and right wheels. The input gear can be engaged by a chain. The wheel clutches can be engaged such that the wheels are driven by the chain. Left and right controls can be used to engage and disengage the respective clutches. For example, upon movement of a control for the left side, the left wheel clutch can be disengaged. Since at this time, power will only be applied to the right wheel, the snowblower will turn left on forward motion. On return of the control from the left to its neutral position, the left wheel clutch is again engaged and the snowblower returns to movement in a straight direction. With the clutches, the wheels can still rotate after disengagement of the respective clutch, thereby widening the turn. 
     In other self-propelled snowblowers, individual brakes can be used to turn the snowblower. An individual brake can be associated with each wheel of a two wheel snowblower. The brakes can be selectively operated to stop rotation of the associated wheel to cause that wheel to stop and the snowblower to turn in the direction of the stopped wheel. With the brakes, the drive system still tries to drive the wheels even after engagement of the respective brake. This makes braking harder and can widen the turn. 
     Therefore, an improved drive assembly for both of the driven wheels is provided that can both brake and clutch the respective wheels to provide independent control of both wheels of a snowblower to turn the snowblower during operation. 
     SUMMARY 
     In accordance with this disclosure, novel drive assemblies and methods are provided. It is therefore an object of the present disclosure to provide novel drive assemblies and methods that provide independent control of both wheels of a snowblower to turn the snowblower during operation. This and other objects as may become apparent from the present disclosure are achieved, at least in whole or in part, by the subject matter described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present subject matter including the best mode thereof to one of ordinary skill in the art is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
         FIG. 1  illustrates a perspective view of an embodiment of a snowblower according to the present subject matter; 
         FIG. 2A  illustrates a top perspective view of the embodiment of the drive assembly according to  FIG. 1 ; 
         FIG. 2B  illustrates a top plan view of the embodiment of the drive assembly according to  FIG. 1 ; 
         FIG. 3  illustrates a cross-sectional view of the embodiment of the drive assembly according to  FIG. 1 ; 
         FIG. 4A  illustrates a cross-sectional view of the embodiment of a brake clutch used in the drive assembly according to  FIGS. 2A ,  2 B, and  3  with the brake clutch in a disengaged or non-braked position; 
         FIG. 4B  illustrates a cross-sectional view of the embodiment of a brake clutch used in the drive assembly according to  FIGS. 2A ,  2 B, and  3  with the brake clutch in an engaged or braked position; 
         FIG. 5A  illustrates an exploded perspective view of the embodiment of the brake clutch of a drive assembly according to  FIG. 1 ; 
         FIG. 5B  illustrates an exploded perspective view of the embodiment of a first portion of the brake clutch of a drive assembly according to  FIG. 5A ; 
         FIG. 5C  illustrates an exploded perspective view of the embodiment of a second portion of the brake clutch of a drive assembly according to  FIG. 5A ; 
         FIG. 5D  illustrates a side view of an embodiment of a bracket used in the brake clutch of a drive assembly according to  FIG. 1 ; 
         FIG. 6  illustrates an embodiment of a portion of the brake clutch of the embodiment of the drive assembly of  FIGS. 2A ,  2 B and  3  with the brake clutch in a braked position according to  FIG. 4B ; and 
         FIG. 7  illustrates an embodiment of a portion of the brake clutch of the embodiment of the drive assembly of  FIGS. 2A ,  2 B, and  3  with the brake clutch in an actuated position according to  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in the figures. Each example is provided to explain the subject matter and not as a limitation. In fact, features illustrated or described as part of one embodiment can be used in another embodiment to yield still a further embodiment. It is intended that the present subject matter cover such modifications and variations. 
       FIG. 1  illustrates a power equipment device shown in one aspect as a snowblower, generally designated  10 , which can use a drive assembly to provide power to one or both wheels  12 A and  12 B of snowblower  10 . It is envisioned that the present disclosure could be used in association with other types of power equipment devices also. Wheels  12 A,  12 B of snowblower  10  can include tires or tracks that can be used to contact the surface over which snowblower  10  travels. Snowblower  10  can have a snow collecting and feeding auger  14  mounted on a frame  16  supported by the pair of wheels by which snowblower  10  is propelled over the ground under the power an engine generally designated  18 . Frame  16  can include steering handles  20 A and  20 B which can provide operator presence controllers  22  and drive controllers  24  for controlling the speed of the engine, wheels, and auger on a control panel  26 . For example, controller  24 A can be provided to control the speed and direction of drive assembly of the wheels. Control panel  26  can be provided between handles  20 A,  20 B and can also provide other control mechanisms. Snowblower  10  can include a discharge chute  28  through which snow collected by the auger  14  can be shot outwardly. 
     Snowblower  10  can also include brake clutch controls, such as levers  29 A and  29 B secured to a bottom side of the respective steering handles  20 A,  20 B. Such brake clutch levers  29 A,  29 B can operate brake clutches associated with the respective wheels  12 A,  12 B to control the rotation of the respective wheels  12 A,  12 B to facilitate steering of the snowblower  10 . For example, brake clutch lever  29 A can be used to control the rotation of right wheel  12 A, while brake clutch lever  29 B can be used to control the rotation of left wheel  12 B. 
     In use, controller  24 A and the brake clutch levers  29 A,  29 B can be used to steer the snowblower  10  to the left or right. The controller  24 A can be used to control the speed and direction of drive assembly of the snowblower  10 . For example, controller  24 A can be used to move the snowblower both forward and backward and can be used to vary the speed in either direction. Once the speed and direction of the snowblower  10  is set, each individual brake clutch lever  29 A,  29 B can be used to activate the associated brake clutch to turn snowblower in different directions by slowing or stopping the rotation of the respective wheel  12 A,  12 B associated therewith. The details of such operations will be described in more detail below. 
       FIGS. 2A ,  2 B, and  3  illustrate a drive assembly generally designated  30  used to drive wheels  12 A and  12 B of the snowblower  10 . Drive assembly  30  can include a transmission system T that can receive torque from a suitable prime mover or motor (not shown), such as an electric motor or an internal combustion engine, through a suitable torque transferring means such as a belt or shaft or the like. Transmission system T can have any configuration suitable for transferring torque from the motor (not shown) to for example a drive shaft  32 . For example, a direct drive transmission system, a standard gear transmission, or any suitable transmission can be used. Accordingly, in some embodiments, transmission system T can be a variable-speed transmission, and particularly a continuously variable-speed transmission. In the embodiment shown in the figures, transmission system T provides a continuously variable transmission (“CVT”) system for turning drive shaft  32  that drives axles generally designated  50  on which wheels  12 A,  12 B of snowblower  10  are attached through gearing, i.e., a series of gears, generally designated  36 . Transmission system T can include at least one transmission wheel  34  that can have an aperture centrally located about its axis through which drive shaft  32  passes. Drive shaft  32  is in independent driving communication with the axles  50  to which the wheels  12 A,  12 B are secured. Transmission system T can also include a drive pulley  40  that is driven by the motor. Transmission wheel  34  can include an outer circumference  38  which has a contact surface  39  that contacts a drive pulley  40 . 
     Drive pulley  40  of drive assembly  30  can have a v-shaped outer circumference  42  in which a drive belt  44  can reside. Drive belt  44  can be driven by engine  18 . The engine can transfer the power to belt  44  which transfers the power to drive pulley  40 . Thereby, drive pulley  40  can be continuously driven while engine  18  is running. Drive pulley  40  can include a drive surface  46  on which contact surface  39  on the outer circumference  38  of transmission wheel  34  runs when transmission wheel  34  is in contact with drive pulley  40 . Transmission wheel  34  can be moved along drive pulley  40  to increase and decrease the speed at which drive shaft  32  and wheels  12  of the snowblower are rotated. Further, transmission wheel  34  can be positioned against drive pulley  40  so as to reverse the direction of rotation of wheels  12  of the snowblower as will be described in more detail below. 
     Variability of the transmission ratio can be accomplished by moving transmission wheel  34  along drive surface  46  of drive pulley  40 . Transmission wheel  34  can be coupled to the drive shaft  32  such that the rotational movement of transmission wheel  34  causes rotational movement of drive shaft  32 . As transmission wheel  34  is rotated by the contact between contact surface  39  and drive surface  46  of drive pulley  40 , transmission wheel  34  rotates drive shaft  32  that can indirectly drive an axle (or axles) on which the wheels of the snowblower can reside. Drive shaft  32  can have an outer surface  48  that can be cylindrical or at least mostly or substantially cylindrical in shape. Alternatively, drive shaft  32  can have a cross-sectional shape that can be rectangular, hexagonal, octagonal, or the like. Further, drive shaft  32  can have a non-symmetrical cross-section. Transmission wheel  34  can be moved along drive shaft  32  by an engager  60  which is in communication and can be controlled by controller  24 A ( FIG. 1 ) through a linking mechanism  62 . 
     Transmission wheel  34  can include an axial bearing at its core that can engage outer surface  48  of drive shaft  32 . The axial bearing can permit transmission wheel  34  to move along drive shaft  32  in lateral directions A and B to vary the transmission ratio within drive assembly  30 . At the same time, the axial bearing can engage drive shaft  32  so as to transfer the torque created by the engagement of transmission wheel  34  to the drive pulley  40  from transmission wheel  34  to drive shaft  32 . The axial bearing can be integral to transmission wheel  34 . 
     Outer surface  48  of drive shaft  32  can be greased to allow movement of transmission wheel  34  along drive shaft  32 . Contact surface  39  can therefore move along drive surface  46  of the drive pulley  40 . This movement along drive surface  46  will vary the speed at which the axles of the wheels of the snowblower will turn. Further, transmission wheel  34  can include an axial bearing at its core that can engage drive shaft  32 . 
     Drive pulley  40  rotates about an axis M. Transmission wheel  34  can travel along a centerline C on drive pulley  40 . Centerline C can intercept and run perpendicular to axis M of drive pulley  40 . Different points along centerline C have been identified to illustrate the operation of the variable drive assembly. When transmission wheel  34  is positioned by engager  60  along drive shaft  32  on the left side of axis M of drive pulley  40 , for example, at point P 1  shown in  FIG. 2A , drive pulley  40  rotates transmission wheel  34  in a reverse direction so that drive shaft  32  is rotated in reverse as well. This rotation causes gearing  36  to rotate axles  50  on which wheels  12 A;  12 B of snowblower  10  can be secured such that wheels  12 A,  12 B rotate in a reverse direction. When transmission wheel  34  is positioned by engager  60  along drive shaft  32  on the right side of axis M of drive pulley  40 , for example, at point P 2 , transmission wheel  34  is in a position on the right side of axis M of drive pulley  40 . In this position, transmission wheel  34  rotates in a forward direction as compared to rotation of the transmission wheel  34  when at point P 1 . As transmission wheel  34  rotates in a forward direction, drive shaft  32  through the bearing connection rotates drive shaft  32  in a forward direction. The rotation of drive shaft  32 , in turn, rotates gears  36  in the forward direction so that the axles  50  and wheels  12 A,  12 B to which they are attached also rotate in the forward direction. 
     When transmission wheel  34  is positioned by engager  60  along drive shaft  32  on the right side of axis M of drive pulley  40 , for example, at point P 3 , transmission wheel  34  is in a position further on the right side of axis M of drive pulley  40 . In this position, transmission wheel  34  rotates in a forward direction at faster speed as compared to rotation of the transmission wheel  34  when at point P 2 . Drive shaft  32  can include stops  64  on either end that limit the amount of movement of transmission wheel  34  along the drive shaft  32  and, in turn, along centerline C of drive pulley  40 . By moving transmission wheel  34  along drive shaft  32  and centerline C of drive pulley  40  among the different points on centerline C such as points P 1 , P 2 , and P 3  between stops  64 , the transmission ratio can be continuously varied therebetween. 
     As transmission wheel  34  moves from point P 3  toward axis M of drive pulley  40 , the speed of rotation of drive shaft  32  and thus axles  50  is slowed. Once transmission wheel  34  passes axis M of drive pulley  40 , drive shaft  32  will turn in the opposite (reverse) direction. By using the bearing system to couple transmission wheel  34  to drive shaft  32  while permitting transmission wheel  34  to laterally move along drive shaft  32  as described above, a continuous variable transmission system is provided. 
     To control the rotation of the individual wheels  12 A,  12 B, respective brake clutches generally designated  70 A and  70 B can be individually activated by their corresponding brake clutch levers  29 A and  29 B. Brake clutch  70 A can be disposed on a right end of drive shaft  32  and brake clutch  70 B can be disposed on a left end of drive shaft  32 . Each brake clutch  70 A,  70 B can include a drive gear  72  that engages a corresponding gearing  36  for the associated wheel  12 A,  12 B. Brake clutches  70 A,  70 B with corresponding drive gears  72  and gearings  36  facilitate the forward and reverse movement of snowblower  10  through the driving of individual wheels  12 A,  12 B. 
     Gearings  36  provide a gearing ratio that sufficiently slows the rotation transferred from the motor to drive pulley  40  by belt  44  to a rotational speed of wheels  12 A  12 B that permits snowblower  10  to progress at varying walking paces for the user. For example, each drive gear  72  can be a smaller sized gear that interacts with a large gear  36 A disposed about a corresponding intermediate shaft MA such that each drive gear  72  turns its corresponding gear  36 A and the intermediate shaft to which the specific gear  36 A is secured. Since gears  36 A are larger than drive gears  72 , the rotation of each intermediate shaft MA can be slower than that of drive shaft  32 . Disposed beside each gear  36 A on the corresponding intermediate shaft MA is a smaller gear  36 B. Thus, as each intermediate shaft MA is turned by its corresponding larger gear  36 A, the corresponding smaller gear  36  is turned at the slower speed of the intermediate shaft MA. 
     Each smaller gear  36 B engages a larger gear  36 C that is disposed on a corresponding axle  50  on which the respective left and right wheels  12 A,  12 B are attached. Since larger gears  36 C are larger than smaller gears  36 B, larger gears  36 C are rotated at a slower rotational speed than the smaller gears  36 B are rotated. The corresponding axles  50  and their associated wheels  12 A,  12 B can be rotated at the slower speeds of the associated larger gears  36 C. In this manner, axles  50  can turn at a slower speed than intermediate shafts MA and much slower than drive shaft  32 . The rotational speed at which drive pulley  40  is driven is reduced to manageable rotational speeds of wheels  12 A,  12 B for the user of snowblower. Consequently, wheels  12 A,  12 B can be rotated at appropriate speeds to permit a user to walk behind and control snowblower  10  without overexertion. 
     As described above, brake clutches  70 A,  70 B control the rotation of the respective wheels  12 A,  12 B. Brake clutches  70 A,  70 B are normally in engaged positions so that drive gears  72  rotate and wheels  12 A,  12 B are driven. When one of the brake clutch levers  29 A,  29 B is activated by the user, the corresponding brake clutch  70 A,  70 B is disengaged so that the associated wheel  12 A,  12 B is not rotated. This causes the snowblower to turn in the direct of the stopped wheel  12 A,  12 B as the other wheel continues to rotate and drive snowblower  10 . 
       FIGS. 3-7  illustrate the components of brake clutches  70 A,  70 B. In particular,  FIGS. 4A and 4B  shows a detailed cross-sectional view of brake clutch  70 A. Brake clutches  70 A,  70 B can reside on small diameter portions  32 A at the ends of drive shaft  32 . Each brake clutch  70 A,  70 B can include a drive hub  74  fixed by a key  76  (see  FIGS. 4A and 4B ) to the corresponding drive shaft  32  in a conventional manner. Each brake clutch  70 A,  70 B also can include a driven member  78  that can be integral with drive gear  72 . Bearing assemblies  80  mount the driven members  78  and drive gears  72  on the drive shaft  32 . Bearing assemblies  80  can be axially restrained on drive shaft  32  between drive hubs  74  and the edges of drive shaft  32  at portions  32 A. Bearing assemblies  80  permit the drive shaft  32  to rotate relative to the driven members  78  and drive gears  72 , as will be discussed later. 
     Alternatively, drive hubs  74  can be secured to the drive shaft  32  by other mechanical connections such as a built-in key, a tongue and groove, splines or a snap ring. Drive hubs  74  can also be integrally formed with the drive shaft  32 . Bearing assemblies  80  can be secured by a press-fit or staking it to either one or both of the drive shaft  32  and the driven members  78  or other similar means can be used. 
     Each driven member  78  can be annular and have a plurality of projections  78   a  spaced along its circumference. These projections  78   a  can extend axially from an upper face  78   b  of the associated driven member  78 . Axial projections  78   a  adjacent one another can define a space  78   c  between them. Each driven member  78  can be axially located on the associated bearing assembly  80  by an annular flange  78   d . Alternatively, a washer or other similar means can position each driven member  78  on each bearing assembly  80 . A plurality of through holes  78   e  ( FIG. 5B ) can be provided in the driven member  78  to facilitate removal of any debris, such as snow and dirt. A stopper  78   g  ( FIG. 5B ) can be provided on the upper surface  78   b  of each driven member  78  in at least one of the spaces  78   c . This stopper  78   g  can be configured as a rib or other suitable shape. 
     As seen in  FIGS. 5A-5C , each brake clutch  70 A,  70 B can include a friction member  82 , a Belleville spring  84 , a brake member  86 , a brake actuator  88 , a plurality of balls  90 , a retainer  92  and a compression spring  94 . The compression spring  94  can be configured to be compressible to a very small axial thickness. One or more compression springs  94  can be used in a brake clutch  70 A,  70 B. By using one compression spring, however, a compact assembly can be used that minimizes the number of parts. 
     Each brake clutch  70 A can be configured to simultaneously displace the brake member  86  and the friction member  82  between respective engaged and disengaged positions, as will be discussed in more detail.  FIG. 4A  represents brake clutch  70 A in an engaged position and  FIG. 4B  represents the brake clutch  70 A in a disengaged position. 
     As seen in  FIGS. 4A ,  4 B, and  5 B, each friction member  82  can have a plurality of radially extending projections  82   a  spaced along its circumference. Each radial projection  82   a  can extend into a corresponding one of the spaces  78   c  and can abut the two adjacent axial projections  78   a . The axial projections  78   a  and the radial projections  82   a  can rotationally secure each friction member  82  to the associated driven member  78 . Each friction member  82  can be a one-piece element which can be a composite including rubber, brass and graphite. 
     Friction members  82  can have a powder metal core  82   e  for reinforcement. The powder metal core  82   e  can be provided with surface ridges to rotationally lock the powder metal core  82   e  within the associated friction member  82 . While the powder metal core  82   e  adds strength to its associated friction member  82 , friction member  82  can function without it. 
     Each Belleville spring  84  contacts both the upper face  78   b  of its associated driven member  78  and a lower surface  82   b  of its associated friction member  82 . Each spring  84  biases the associated friction member  82  axially away from the corresponding driven member  78 . The interaction of these axial projections  78   a  and these radial projections  82   a  can permit the friction member  82  to be axially displaced relative to the driven member  78 . 
     A clutch surface  82   c  formed on the inner circumference of each friction member  82  can selectively engage a frusto-conical outer surface  74   a  on the corresponding drive hub  74 . Clutch surface  82   c  can also be frusto-conical. Forming this clutch surface  82   c  as a frusto-conical surface maximizes surface area with a minimum radial dimension. 
     Each spring  84  biases the associated clutch surface  82   c  into contact with the frusto-conical outer surface  74   a  of the associated drive hub  74 . This frictional contact allows the drive hub  74  to drive the associated driven member  78 . 
     A brake surface  82   d  can be provided on the upper surface of each friction member  82 . Brake surface  82   d  and the clutch surface  82   c  can be provided on separate (the upper and the inside) surfaces of each friction member  82  to save space and minimize the number of elements needed for each brake clutch  70 A,  70 B. 
     As seen in  FIGS. 4A ,  4 B, and  5 C, each brake member  86  can have at least one brake shoe  86   a , and preferably, a plurality of brake shoes  86   a  circumferentially spaced about its periphery. The brake shoes  86   a  can extend axially downward from the bottom of the brake member  86 . Each brake shoe  86   a  can have a braking surface  86   b  that can selectively engage brake surface  82   d  on the associated friction member  82 . 
     Brake actuator  88  of each brake clutch  70 A,  70 B can be coaxially disposed above the associated brake member  86 . A bearing assembly  96  can allow the respective brake actuator  88  to be mounted for relative rotation on drive shaft  32 . Each bearing assembly  96  can be press fit onto drive shaft  32  and the associated brake actuator  88 . Alternatively, each bearing assembly  96  can be retained by staking the bearing assembly  96  to any combination of drive shaft  32 , brake actuator  88  and drive hub  74 . 
     Each brake actuator  88  can have a plurality of circumferentially spaced arcuate slots  88   a . A rib  88   b  can extend across a respective one of the arcuate slots  88   a  as shown in  FIG. 5C . A plurality of arcuate slots  86   c  can be circumferentially spaced on each brake member  86 . A portion of each brake member arcuate slot  86   c  can overlap a corresponding brake actuator arcuate slot  88   a  with the remainder extending beyond the corresponding brake actuator arcuate slot  88   a.    
     The retainer  92  used in each brake clutch  70 A,  70 B can be a flat annular disk with a plurality of hooks  92   a  extending axially upward from the circumference of the retainer  92 . Each retainer  92  can be coaxially disposed below the associated brake actuator  88  and radially inside of the associated brake shoes  86   a . Each hook  92   a  can project through arcuate slots  86   c  and  88   b  in the associated brake member  86  and the associated brake actuator  88 . Each hook  92   a  can be secured on a respective rib  88   b . Each retainer  92  can be coated with a low friction material, such as polytetraflouroethylene (PTFE) or nylon. This low friction coating allows for an easier return of the respective retainer  92  to its neutral position, as described further below. 
     One or more compression springs  94  are captured between the bottom of each brake member  86  and the upper surface of the associated retainer  92 . Each retainer  92  connects the associated brake member  86  to the associated brake actuator  88 , and the one or more compression springs  27  biases the associated brake member  86  away from the associated brake actuator  88 . 
     A plurality of ball ramp assemblies can form a connection between each brake member  86  and its associated brake actuator  88  for the respective brake clutches  70 A,  70 B, Each ball ramp assembly can comprise inclined ball ramp surfaces  86   d ,  88   c  formed in each of the respective brake members  86  and brake actuators  88 . Ball ramp surfaces  86   d  oppose ball ramp surfaces  88   c  and are inclined in the opposite direction relative to the ball ramp surfaces  88   c . A ball  90  can be movably captured between each pair of opposed ball ramp surfaces  86   d  and  88   c , respectively. 
     As an example, three ball ramp surface pairs can be used and located on each brake member  86  and each brake actuator  88  at points that form a triangular configuration as shown in  FIGS. 6 and 7 . Arcuate slots  86   c  of each brake member  86  can be positioned inward of and proximal to a corresponding ball ramp surface  86   d . Similarly, each arcuate slot  88   a  of each brake actuator  88  can be positioned inward of and proximal to a corresponding ball ramp surface  88   c . Hooks  92   a  of retainer  92  are thus located inward of and proximal to the brake ramp surfaces  86   d  and  88   c . This arrangement positions the hooks  92   a  of the respective retainer  92  close to the ball ramp surfaces  86   d ,  88   c  of the respective brake member  86  and brake actuator  88 . With this arrangement, the force from the one or more compression springs  94  is located inward of the ball ramp surfaces  86   d ,  88   c  and close to these ball ramp surfaces  86   d ,  88   c . This arrangement creates better actuation between the ball ramp surfaces  86   d ,  88   c , and the balls  90  contained therein. Also, the arrangement aids in containing the balls  90  between the respective ball ramp surfaces  86   d ,  88   c . This enhances the performance of the respective brake clutch  70 A,  70 B in which the arrangement is used. However, hooks  92   a  of each respective retainer  92  can be located in other positions. 
     A tab  86   e  can extend radially from the circumference of each brake member  86 , and an arcuate tab slot  86   f  can be formed in tab  86   e . Each brake actuator  88  can have a projection  88   d  that can extend axially downward through tab slot  86   f . The width of projection  88   d  can be less than the arcuate length of tab slot  86   f . As described further below, projection  88   d  can serve as an abutment and slot  86   f  can serve as stop. In other embodiments, the abutment can be on respective brake member  86  and the stop can be on the respective brake actuator  88 . 
     Alternatively, other couplings that convert rotary motion to axial motion can be used instead of the ball ramp surface assemblies, such as a cam and follower assembly. Other embodiments can forgo any rotational motion of the brake actuator such a linkage system that provides a linearly displaceable link in contact with the brake member. 
     Referring to  FIGS. 5D ,  6  and  7 , a bracket  98  can be secured to a bracket tab  86   g  on each brake member  86  by a post  98   a . Post  98   a  can extend axially downward through an opening  86   h  in bracket tab  86   g  of each brake member  86 . Brake member  86  is free to move axially along post  98   a . Bracket  98  can be secured to a mounting surface, such as a frame or an engine block of snowblower  10 , by bolts or other suitable fastenings arrangements. Thus, bracket  98  can rotationally fix brake member  86 . Alternatively, brake member  86  can be rotationally secured by a bolt or similar fastening arrangement. 
     Each bracket  98  can include a guide flange  98   c  that defines a hole  98   b  therein. A projection  88   e  can extend axially upward from the top surface of each brake actuator  88 . One end of the associated control cable CC R , CC L  can pass through hole  98   b  and guide flange  98   c  and can be secured to projection  88   e  by way of a slot or a hole or any other similar manner for each brake clutch  70 A,  70 B. The other end of the respective control cable CC R , CC L  can be secured to the associated brake clutch lever  29 A,  29 B. 
     Alternatively, the respective control cable CC R , CC L  can be secured at one end to a hole in brake actuator  88 . A coil spring  100  can be secured in each brake clutch  70 A,  70 B at one end to bracket  98  at a recess  98   d . The other end of coil spring  100  can be secured to a spring tab  88   f  formed at the periphery of the respective brake actuator  88 . Recess  98   d  could be replaced by a hole or aperture in an alternate embodiment. Each bracket  98  can include a plurality of ribs  98   e  along its body to assist in the support of guide flange  98   c  and the flange containing recess  98   d . However, each bracket  98  does not need to be provided with such ribs. 
     Each bracket  98  can be a single element providing the functions of rotationally fixing the respective brake member  86 , anchoring the respective control cable CC R , CC L , and anchoring the respective coil spring  100 . Such an embodiment of bracket  98 ; therefore, can contribute to the reduction of parts for assembly. 
     Operation of the each brake clutch of the invention will now be described with references to  FIGS. 3-7 .  FIG. 6  shows a top view of the brake clutch  70 A in a disengaged position as shown in the cross-sectional view of  FIG. 4B .  FIG. 7  shows a top view of brake clutch  70 A in an engaged position as shown in the cross-section view of  FIG. 4A . Actuation of brake clutch lever  29 A actuates control cable CC R  to impart a rotational motion to brake actuator  88 . This, in turn, causes each ball ramp surface  88   c  to move relative to the associated ball  90 . Each ball  90  rolls along the opposite inclined ball ramp surface  86   d  of brake member  86 . This motion of the balls  90  forces the brake member  86  axially downward against the bias of compression spring  94  to engage braking surface  86   b  of brake member  86  with brake surface  82   d  of friction member  82  as can be seen in  FIG. 6 . Brake actuator  88  is in the braked position shown in  FIG. 6  with the balls  90  rolled toward the narrow portions of inclined ramp surfaces  86   d ,  88   d . At such point, the diameter of the balls  90  push brake member  86  away from brake actuator  88  as shown in  FIG. 4B  to engage the braking surface  86   b  of brake member  86  against the brake surface  82   d  of friction member  82 . 
     Thereby, rotation of the brake actuator  88  by displacement of the control cable CC R  causes the braking surface  86   b  to axially displace the friction member  82  axially downward toward the driven member  78  against the bias of Belleville spring  84 . This downward movement of friction member  82  gradually disengages clutch surface  82   c  from frusto-conical surface  74   a  of the drive hub  74 . This motion eventually completely disengages driven member  78  from drive hub  74  and drive shaft  32  and retards the rotation of driven member  78 . At this point, stopper  78   g  is engaged by the bottom surface  82   b  of the friction member. Drive gear  72  associated with driven member  78  of brake clutch  70 A thus stops rotation with drive shaft  32 . 
     Consequently, associated gearing  36  stops rotation, which in turn stops associated axle  50  and right wheel  12 A from rotating. Since right wheel  12 A stops rotation, snowblower  10  with its left wheel  12 B still being driven turns to the right. In a similar manner, snowblower  10  would turn to the left, if the brake clutch lever  29 B was actuated. 
     By releasing brake clutch lever  29 A, control cable CC R  moves in the opposite direction and rotates brake actuator  88  in the opposite direction, which, in turn, displaces brake member  86  upward from brake surface  82   d  of friction member  82 . This motion gradually disengages the braking surface  86   b  of brake member  86  from brake surface  82   d  of friction member  82 . This rotation of brake actuator  88  moves it into a disengaged position shown in  FIG. 7  with balls  90  rolled toward the wider portions of the inclined ramp surfaces  86   d ,  88   c . At this point, balls  90  permit brake member  86  to move toward brake actuator  88  as shown in  FIG. 4A  and braking surface  86   b  of brake member  86  to disengage brake surface  82   d  of friction member  82 . 
     Simultaneously, the clutch surface  82   c  is gradually brought into engagement with the frusto-conical surface  74   a  of drive hub  74  due to the bias of Belleville spring  84 . This motion eventually completely engages driven member  78  with drive hub  74  and drive shaft  32  and facilitates the rotation of driven member  78 . Thereby, drive gear  72  associated with driven member  78  of brake clutch  70 A is again rotated by drive shaft  32 . Consequently, associated gearing  36  is rotate, which, in turn, rotates associated axle  50  and right wheel  12 A. Since right wheel  12 A is rotating, snowblower  10  with its left wheel  12 B still being driven returns to a straight forward movement. 
     Rotation of brake actuator  88  relative to brake member  86  can be limited by the interaction of projection  88   e  of brake actuator  88  with tab slot  86   f  of brake member  86 . As seen in  FIGS. 6 and 7 , one end  86   i  of tab slot  86   f  defines a first limit of brake actuator  88  and the other end  86   j  of tab slot  86   f  defines a second limit of brake actuator  88 . When brake actuator  88  is in the first limit position at end  86   i  as shown in  FIG. 6 , brake shoe  86   a  is engaged with brake surface  82   d  of friction member  82 . When brake actuator  88  is in the second limit position at end  84   j  as shown in  FIG. 7 , brake shoe  86   a  is disengaged from brake surface  82   d  of friction member  82 . 
     The force exerted by coil spring  100  is directed on brake actuator  88  in such a manner as to overcome the bias of compression spring  94 . Thus, coil spring  100  biases brake actuator  88  towards the first limit position. This ensures that brake member  86  brakes friction member  82  against rotation until an operator provides input to brake actuator  88  through control cable  100 . 
     In operation, brake clutch levers  29 A,  29 B can be used control the rotation of respective right and left wheels  12 A,  12 B through the operations of brake clutches  70 A,  70 B as described above, independent from one another. This facilitates easier turning of snowblower  10 . Thus, by stopping rotation of either wheel  12 A,  12 B by actuating the associated brake clutch lever  29 A,  29 B and brake clutch  70 A,  70 B, snowblower  10  can be turned to the right or the left with ease. Such control can occur whether transmission wheel  34  is located on either side of axis M (forward or reverse) of drive pulley  40  or at any various locations along centerline C (speed). 
     Embodiments of the present disclosure shown in the drawings and described above are exemplary of numerous embodiments that can be made within the scope of the appending claims. It is contemplated that the configurations described herein can comprise numerous configurations other than those specifically disclosed. The scope of a patent issuing from this disclosure will be defined by these appending claims.