Abstract:
A hydraulic power take-off is provided for use with industrial drives. The hydraulic power take-off has a multiple-force brake system that facilitates actively slowing large inertial loads associated with a heavy rotating mass of an industrial machine. The multiple-force brake system applies different braking forces at different times to control deceleration of the heavy rotating mass in the industrial machine to reduce its stopping time. The multiple-force brake system may include a clutch assembly and a brake assembly. A control system may control the clutch and brake assemblies to provide the multiple-force brake system a relatively higher energy brake engagement state and a relatively lower energy brake engagement. This may include alternating between the higher and lower energy brake engagement states to pulse between high and low pressure braking to facilitate cooling of the system while slowing the large inertial loads.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims a benefit of priority under 35 USC §119 to U.S. Provisional Patent Application No. 62/296,928 filed Feb. 18, 2016, the entire contents of which are hereby expressly incorporated by reference into the present application. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The preferred embodiments are directed to industrial drives of industrial equipment and, more particularly, to a hydraulic PTO (power take-off) that can provide a dynamic braking action to large rotating components of industrial machines for reducing rotational speed of corresponding large inertial loads. 
         [0004]    Discussion of the Related Art 
         [0005]    Industrial equipment like industrial chippers, shredders, grinders, and crushers having large rotating components that are driven with robust industrial drives. Suitable industrial drives include hydraulic PTOs with hydraulic clutches that selectively connect and disconnect power between the driven industrial equipment and prime movers. Some hydraulic PTOs have internal brake assemblies for stopping and holding the large rotating components of the industrial equipment. 
         [0006]    For simplicity and reliability in most applications, each internal brake assembly of a hydraulic PTO typically has a single clutch plate with a single braking surface. Single plate brake assemblies are limited in their use for stopping large rotating components of industrial equipment. That is because the large rotating components have enough mass to establish large inertial loads, which present numerous challenges while trying to actively brake, especially with single plate brake assemblies. Actively braking the large rotating components creates substantial heat in brake assemblies, potentially creating over-heating issues. Instead of actively braking, heat-induced issues in brake assemblies are avoided by allowing the rotating components to coast down to slow speeds before using the brake assemblies for slow speed final-stopping and holding or parking-type brake applications. Some rotating components are allowed to coast down to about 40 RPM (rotations per minute) or less before performing the brake application that performs the slow speed final-stopping. This coast-down process can take several minutes or more, during which time no servicing or other procedures can be performed on the industrial equipment. 
         [0007]    Overall, a hydraulic PTO for use in an industrial drive of a piece of industrial equipment that allows for active braking of large rotating components of the industrial equipment to reducing stopping time was desired. 
       SUMMARY AND OBJECTS OF THE INVENTION 
       [0008]    The preferred embodiments overcome the above-noted drawbacks by providing a hydraulic PTO (power take-off) for use with an industrial drive and by having a multiple-force brake system that is controlled to alternatingly apply relatively higher and lower energy brake engagement states to slow large rotating components with large inertial loads while maintaining suitable operating temperatures within the hydraulic PTO. 
         [0009]    In accordance with a first aspect of the invention, a hydraulic PTO is provided that includes a PTO housing mounted between a prime mover and a piece of driven industrial equipment. An output shaft extends from the PTO housing to selectively deliver power to the piece of driven equipment for driving rotation of a rotatable component of the piece of driven industrial equipment. A multiple-force brake system is configured to apply different braking forces at different times to control deceleration of the rotatable component of the piece of driven industrial equipment while stopping the rotation of the rotatable component of the piece of driven industrial equipment. A control system may be configured to control the multiple-force brake system to alternately pulse applications of high-energy brake engagement and low-energy brake engagement. The multiple-force brake system may include a brake assembly with first and second sets of springs that provide first and second forces that correspond to the high-energy brake engagement and low-energy brake engagement. The first set of springs may be arranged to bias a clutch piston of a clutch assembly of the hydraulic PTO to disengage the clutch assembly and apply the force that corresponds to the high-energy brake engagement. The second set of springs may be arranged to bias a brake piston of a brake assembly and apply the force that corresponds to the low-energy brake engagement. 
         [0010]    In accordance with another aspect of the invention, a hydraulic PTO for use with industrial drives is provided that has an input end receiving power from a prime mover and an output end having an output shaft selectively rotating to deliver power to a piece of industrial equipment. A clutch assembly receives power from the prime mover and selectively transmits the power into rotation of the output shaft. The clutch assembly can be engaged to transmit power through the clutch assembly for rotating the output shaft and disengaged to not transmit power through the clutch assembly. The clutch assembly may include a clutch pack having interleaved clutch plates clamped together for rotation in unison with each other when the clutch assembly is engaged and unclamped with respect to each other permitting rotation past each other when the clutch assembly is disengaged. A clutch piston is configured to be moved by hydraulic pressure toward the clutch pack to engage the clutch assembly. Clutch return springs engage the clutch piston and move the clutch piston away from the clutch pack to disengage the clutch assembly. A brake assembly may be arranged between the clutch assembly and the output shaft to apply a braking force for stopping rotation of the output shaft when power is not being delivered to the piece of industrial equipment. The brake assembly may include a brake pack having interleaved brake plates configured to clamp against each other to apply the braking force. A brake piston is arranged at a first side of the brake pack. A brake pressure cavity is configured to receive hydraulic oil to create hydraulic pressure that pushes the brake piston toward the brake pack. A brake piston stop is arranged to limit movement of the brake piston toward the brake pack. Brake piston springs bias the brake piston in a first direction toward the brake pack. A brake backing plate is arranged at an opposite side of the brake pack than the brake piston. A pin(s), which may be implemented as a set of pins, extends between the clutch piston and the brake backing plate to translate movement of the clutch piston away from the clutch pack into movement of the brake backing plate toward the brake pack. A control system selectively commands application of a high-energy braking force or a low-energy braking force through the brake assembly for slowing rotation of the output shaft. The high-energy braking force corresponds to the brake plates of the brake pack clamped against each other with a relatively greater clamping force when the brake piston engages the brake piston stop and the clutch return springs bias the clutch piston, the pin(s), and brake backing plate toward the brake pack. The low-energy braking force corresponds to the brake plates of the brake pack clamped against each other with a relatively lesser clamping force when hydraulic pressure is released from the brake pressure cavity such that substantially the entirety of the relatively lower clamping force is provided by the biasing force of the brake piston springs. 
         [0011]    These and other features and advantages of the invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout and in which: 
           [0013]      FIG. 1  is a simplified schematic representation of a piece of industrial equipment with an industrial drive incorporating a hydraulic PTO (power take-off) with a multiple-force brake system; 
           [0014]      FIG. 2  is a pictorial view of the hydraulic PTO of  FIG. 1 ; 
           [0015]      FIG. 3  is a side elevation view of a portion of the hydraulic PTO of  FIG. 2 ; 
           [0016]      FIG. 4  is a longitudinal cross-sectional view of a portion of the hydraulic PTO of  FIG. 2 ; 
           [0017]      FIG. 5  is a longitudinal cross-sectional view of a portion of the hydraulic PTO of  FIG. 2  with the clutch assembly engaged and the brake assembly disengaged; 
           [0018]      FIG. 6  is a longitudinal cross-sectional view of a portion of the hydraulic PTO of  FIG. 2  with the clutch assembly disengaged and the brake assembly in a high-energy brake engagement state; 
           [0019]      FIG. 7  is a longitudinal cross-sectional view of a portion of the hydraulic PTO of  FIG. 2  with the clutch assembly disengaged and the brake assembly in a low-energy brake engagement state; 
           [0020]      FIG. 8  is a longitudinal cross-sectional view of a portion of the hydraulic PTO of  FIG. 2  showing a disconnect system; 
           [0021]      FIG. 9  is a transverse cross-sectional view of a portion of the hydraulic PTO of  FIG. 2  showing the disconnect system of  FIG. 8 ; and 
           [0022]      FIG. 10  is a longitudinal cross-sectional view of a disconnect lever assembly of the disconnect system of  FIG. 8 . 
       
    
    
       [0023]    In describing preferred embodiments of the invention, which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the words “connected”, “attached”, “coupled”, or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0024]    Referring now to the simplified schematic representation in  FIG. 1 , a hydraulic PTO (power take-off)  5 , with a multiple-force brake system  10 , is shown implemented in an industrial drive  15 . The industrial drive  15  delivers power from a prime mover  20 , which may be a high-power internal combustion engine to a piece of industrial equipment  25 . Industrial drive  15  is shown here configured for side-load power delivery and includes a pulley arrangement  30  and belt(s)  35  that transmit power from hydraulic PTO  5  to a driven component(s) of the industrial equipment  25 . The industrial equipment  25  may be, for example, a whole-tree chipper or other industrial wood chipper, a heavy-duty pump system, a grinder, a crusher, a dredge, a shredder, or a heavy-duty drill system that has a large rotating mass such as a rotatable component(s)  40  that establishes large inertial loads while rotating. A control system  45  includes a computer that executes various medium-stored programs while receiving inputs from, and sending commands to, the hydraulic PTO  5  to control the hydraulic PTO  5  and may further control other components of the industrial drive  15 , prime mover  20 , and/or other components of the industrial equipment  25 . Control system  45  may include the TDEC-050 electronic control system available from Twin Disc®, Inc. for controlling the hydraulic PTO  5  by controlling the various electronic, electromechanical, and hydraulic systems and/or other components of the hydraulic PTO  5  to control hydraulic fluid flow to actuate components to selectively engage and disengage components of multiple-force brake system  10 . This may include toggling between high and low energy braking engagements during a stopping event, as explained in greater detail elsewhere herein. 
         [0025]    Referring to  FIG. 2 , hydraulic PTO  5  includes a housing  50  with an input end  55 , an output end  60  or, as shown here, a pump tower  70  shown with two pump pads  75  arranged between the input and output ends  55 ,  60 . Referring to  FIGS. 3 and 4 , multiple-force brake system  10  is arranged inside of the housing  50 . Referring now to  FIG. 4 , multiple-force brake system  10  includes a clutch and brake arrangement  80  having a clutch assembly  85  and brake assembly  90 . Clutch assembly  85  receives power from an input shaft  95  toward the housing input end  55  and selectively delivers power to output shaft  100  toward the housing output end  60 . Brake assembly  90  is shown here as a multi-disc or multi-plate wet brake system that is configured to slow the rotational speed of output shaft  100  by selectively using different clamping or braking forces as controlled by control system  45 .  FIGS. 5-7  show the multiple-force brake system  10  in different states of clutch engagement and braking force application. 
         [0026]    Referring now to  FIG. 5 , multiple-force brake system  10  is shown with the clutch assembly  85  on or engaged and the brake assembly  90  off or disengaged to transmit power through the hydraulic PTO  5 . A drum assembly  105  interconnects the clutch assembly  85  and brake assembly  90  by way of a clutch drum  110  and a brake collar  115  with a flange  120  that extends between and connects the clutch drum  110  with the brake collar  115  to each other. Clutch drum  110  is spline-mounted to output shaft  100  and has outer and inner circumferential clutch drum side walls  125 ,  130 . 
         [0027]    Still referring to  FIG. 5 , clutch assembly  85  has a clutch pack  135  with interleaved clutch plates  140 . A first set of clutch plates  140  of clutch pack  135  is locked into rotational unison with clutch drum  110  through engagement of outwardly facing tabs of the clutch plates  140  with splined grooves of an inner surface of an outer clutch drum side wall  125 . A second set of clutch plates  140  of clutch pack  135  is locked into rotational unison with input shaft  95  ( FIG. 4 ) through engagement of inwardly facing tabs of the clutch plates  140  with splined grooves of an outer surface of the input shaft  95 . A clutch piston assembly  150  with a clutch piston  155  that moves to compress the clutch plates  140  against each other and lock the clutch plates  140  into rotational unison when hydraulic fluid is introduced into a clutch pressure cavity  160  is also provided. This engagement of clutch assembly  85  allows the clutch pack  135  to translate rotation of the input shaft  95  ( FIG. 4 ) into rotation of the output shaft  100 . 
         [0028]    Still referring to  FIG. 5 , brake assembly  90  has a brake stack or brake pack  170  with interleaved brake plates  175 . A first set of brake plates  175  of brake pack  170  is locked against rotation with respect to housing  50  through engagement of outwardly facing tabs of the brake plates  175  with inwardly facing splined grooves of an inner surface of housing  50  or, as shown here, a brake ring  180  so that the first set of brake plates  175  is rotationally fixed with respect to the brake ring  180 . Brake ring  180  is configured to be selectively locked against rotation with respect to housing  50  or released and mechanically disconnected to allow the brake ring  180  to rotate with respect to housing  50 , as explained in greater detail elsewhere herein. A second set of brake plates  175  of brake pack  170  has inwardly facing tabs that are received in outwardly facing splined grooves of an outer surface of brake collar  115  of drum assembly  105 , which locks the second set of brake plates  175  into rotational unison with output shaft  100  through the drum assembly  105 . The brake plates  175 , brake ring  180 , and brake collar  115  are shown with annular configurations, when viewed from end views, and concentrically arranged within an annular brake assembly opening of the PTO housing  50 . A brake piston assembly  185  has a brake piston  190  that can be hydraulically actuated to move to compress the brake plates  175  against each other as supported by a backing plate  195  and clutch piston assembly  150  when hydraulic fluid is introduced into a brake pressure cavity  200  for creating frictional drag between the fixed and rotating brake plates  175  to brake the output shaft  100 . Backing plate  195  floats like the other brake plates  175  and transfers the force of the clutch piston  155  when the clutch assembly  85  is not activated. 
         [0029]    Referring again to  FIGS. 5-7 , a multiple-force spring system  205  allows the multiple-force brake system  10  to provide different braking forces of different magnitudes at different times, as controlled by control system  45  ( FIG. 1 ). Multiple-force spring system  205  includes multiple springs, shown here as high-strength springs  210  as a first set of springs, shown as clutch return springs, and low-strength springs  215  as a second set of springs, shown as brake piston springs. Each of high-strength springs  210  is supported at one end by a plate  220  held by a retainer  225  at the clutch drum  110  and, at a second end, engages and biases the clutch piston  155  away from clutch plates  140  to disengage clutch assembly  85 . Each of low-strength springs  215  is supported at one end by housing  50  and, at a second end, engages and biases the brake piston  190  toward brake plates  175  to engage brake assembly  90 . Pins  230  extend through openings  235  of the drum assembly flange  120 . The pins  230  are configured to allow movement of the clutch piston  155  of clutch assembly  85  toward the drum assembly flange  120  to translate into movement of back plate  195  of brake assembly  90  away from the drum assembly flange  120  and toward the brake piston  190 . 
         [0030]    Referring again to  FIG. 5 , when the clutch assembly  85  is engaged, hydraulic pressure in the clutch pressure cavity  160  moves the clutch piston  155  to compress the clutch pack  135 , which compresses the high-strength springs  210  and unloads pin  230  to allow the pin  230  to disengage from back plate  195  of the brake assembly  90 . This simultaneously engages the clutch assembly  85  and disengages or turns off brake assembly  90  because low-strength springs  215  can remain fully extended and unloaded, with no resistance or stop provided by pins  230  because the pins  230  are slid out of engagement with back plate  195 , which defines a clearance or gap  240 . It is contemplated that back plate  195  could be attached to the pins  230  with screws or other fasteners to pull the back plate  195  away from the brake pack  170  during a clutch engagement. 
         [0031]    Referring now to  FIG. 6 , multiple-force brake system  10  is shown with the clutch assembly  85  off or disengaged and the brake assembly  90  on or engaged to provide braking of output shaft  100  with a relatively high-energy brake engagement. In the high-energy brake engagement state of multiple-force brake system  10 , the high-strength springs  210  provide the braking pressure to the brake assembly  90 . This is done by introducing oil into the brake pressure cavity  200  to create hydraulic pressure that pushes brake piston  190  toward the brake pack  170  until the brake piston  190  hits a stop provided by an abutment or engagement between the brake piston  190  and an end surface of the brake ring  180 . The hydraulic pressure is maintained to hold the brake piston  190  against the stop at the brake ring  180 . The clutch assembly  85  is turned off or disengaged by relieving hydraulic pressure from the clutch pressure cavity  160 . The high-strength springs  210  push the clutch piston  155  away from the clutch pack  135 , which axially loads and pushes pin  230  against back plate  195 , with the movement permitted by a clearance or gap  245  and defined between clutch piston  155  and drum assembly flange  120 . The translation of movement of the clutch piston  155  through the pin  230  to push against back plate  195  compresses brake pack  170  with a relatively high clamping force provided by high-strength springs  210 , which provides a high-energy braking force. 
         [0032]    Referring now to  FIG. 7 , multiple-force brake system  10  is shown with the clutch assembly  85  off or disengaged and the brake assembly  90  on or engaged to provide braking of output shaft  100  with a relatively low-energy brake engagement. In the low-energy brake engagement state of multiple-force brake system  10 , the low-strength springs  215  provide the braking pressure to the brake assembly  90 . This is done by releasing hydraulic pressure from both the clutch and brake pressure cavities  160 ,  200 . The high-strength springs  210  push the clutch piston  155  away from the clutch pack  135 , against a stop provided by an abutment between the clutch piston  155  and a surface of the drum assembly flange  120 . This holds the back plate  195  in a fixed position against which the low-strength springs  215  push the brake piston  190  to compress the brake pack  170 , which creates a clearance or gap  250  between the brake piston  190  and the brake ring  180 . The compression of brake pack  170  provided by the low-strength springs  215  provides a low-energy braking force. 
         [0033]    Referring again to  FIGS. 5-7  and with further reference to  FIG. 1 , during use, control system  45  ( FIG. 1 ) controls the multiple-force brake system  10  to actively brake rotation of the rotatable component(s)  40  ( FIG. 1 ) of the industrial equipment  25  ( FIG. 1 ). During a braking event, the control system  45  can toggle between applications of the high-energy and low-energy braking forces. The periodic applications of the high-energy braking forces provide substantial slowing of the rotatable component(s)  40  ( FIG. 1 ) and the periodic applications of the low-energy braking forces provide some braking effect while allowing cooling of the oil and system components of the hydraulic PTO  5 . 
         [0034]    Referring now to  FIGS. 8 and 9 , hydraulic PTO  5  includes a manual service disconnect system, shown as disconnect system  255 , to at least partially release the multi-disc wet brake system of brake assembly  90 . This may be done by mechanically disconnecting the brake assembly  90  from its supporting components to allow rotation of the brake assembly  90  relative to PTO housing  50 . When the industrial equipment  25  ( FIG. 1 ) is in use, the brake assembly  90  is in a non-parking brake state to allow rotation of output shaft  100  ( FIG. 4 ) relative to the brake assembly  90 , such as rotation relative to the brake plates  175  that are rotationally fixed with respect to brake ring  180  and locked against rotation with respect to PTO housing  50 , to deliver power to industrial equipment  25  ( FIG. 1 ). When the industrial equipment  25  ( FIG. 1 ) is not in use, the brake assembly  90  can be in a parking brake state, providing a parking brake effect by way of the low-energy braking force provided by the low-strength springs  215  ( FIG. 5 ) against the multiple brake plates  175  in the brake pack  170 . This prevents rotation of output shaft  100  ( FIG. 4 ) relative to the brake assembly  90 , such as relative to all of the brake plates  175  of brake pack  170 . 
         [0035]    Disconnect system  255  is configured to manually release the parking brake to place the brake assembly  90  in a parking brake disconnected state in which the brake assembly  90  is mechanically disconnected from its supporting structure of PTO housing  50  and allowed to rotate relative to the PTO housing  50 . This allows rotating components of the industrial equipment  25  ( FIG. 1 ) and/or output shaft  100  ( FIG. 4 ) when the brake assembly  90  is in the parking brake disconnected state, as explained in greater detail elsewhere herein. 
         [0036]    Still referring to  FIGS. 8 and 9 , disconnect system  255  includes brake ring  180  and disconnect lever assembly  260  that can selectively engage the brake ring  180  to lock and prevent rotation of brake ring  180  within the housing  50  during active braking or parking braking with the brake assembly  90 . Disconnect lever assembly  260  can selectively release the brake ring  180  to allow rotation of brake ring  180  and rotation of output shaft  100 . When the brake ring  180  is released and allowed to rotate in the housing  50 , the brake assembly  90  applies a small fraction of the braking power compared to when the brake ring  180  is prevented from rotating within the housing  50 . That is, because the brake ring  180  is allowed to rotate inside the housing  50 , braking occurs at only a single frictional engagement surface between the outermost brake plate  175  and the piston  190 , instead of multiple frictional engagements of multiple abutting surfaces of the adjacent interleaved brake plates  175  when the brake ring  180  is locked against rotation. By locking and releasing the brake ring  180  with the disconnect lever assembly  260 , the disconnect system  255  converts the brake assembly  90  from a multi-plate configuration when in the parking brake state to effectively provide a single plate configuration that is substantially easier to rotate through when placed in the parking brake disconnected state. 
         [0037]    Referring to  FIGS. 8 and 9 , brake ring  180  has inner and outer circumferential surfaces  265 ,  270 . Inner circumferential surface  265  supports the brake plates  175  with the outwardly facing tabs. Outer circumferential surface  270  faces outward toward an inwardly facing surface of a wall that defines an outer boundary of the annular brake assembly opening of the PTO housing  50 . Holes or brake ring pockets, shown as pockets  280 , extend into the outer circumferential surface  270  of brake ring  180  and are circumferentially spaced from each other. Disconnect lever assembly  260  includes handle  315  with a plunger  290  that extends into pocket(s)  280  to lock the brake ring  180  and is withdrawn out of pocket  280  to release and allow the brake ring  180  to rotate. Plunger  290  is arranged for sliding concentrically in a bore  295  of cylindrical lever body  300  that is attached to housing  50 , extending through a bore  305  of the housing  50  that is aligned with the brake ring  180  and the pockets  280 . 
         [0038]    Turning to  FIG. 10 , pin  310  is connected to and extends outwardly from plunger  290  through bore  295 , and a handle  315  extends perpendicularly from an upper end of pin  310 . A slot  320  extends through a sidewall  325  of the cylindrical lever body  300 . The slot  320  is configured to receive the handle  315  so that the handle  315  is advanced downwardly in the slot  320  to define a first position of handle  315  when the plunger  290  is seated in pocket  280 . To withdraw the plunger  290  out of pocket  280 , the handle  315  is withdrawn from the slot  320  and rotated to sit on an upper end  330  of the cylindrical lever body  300  to define a second position of handle  315 , as shown in dashed outline in  FIG. 10 . A spring  335  is arranged concentrically between pin  310  and sidewall  325  of the cylindrical lever body  300 . A lower end  340  of spring  335  sits against an upper surface  345  of plunger  290 . An upper end  350  of spring  335  sits against an internal shoulder  355  of the cylindrical lever body  330 . Spring  335  is a compression spring that biases the plunger  290  toward brake ring  180  so that, if handle  315  is aligned with slot  320 , the plunger  290  automatically falls into a pocket  280  that rotates into alignment with the plunger  290  when the brake ring  180  rotates. 
         [0039]    Referring again to  FIG. 9 , a sensor shown as switch  360  is configured to detect when the brake ring  180  is in a home position in which the disconnect lever assembly  260  locks the brake ring  180  with respect to the housing  50 . Switch  360  is shown as a plunger-style switch with a switch button that remains in an extended position by extending into a pocket  280  when the brake ring  180  is in the home position, such as the position shown in  FIG. 9 . When the brake ring  180  is not in the home position, the button of switch  360  engages the outer circumferential surface  270  of brake ring  180 , which pushes the switch button into the switch  360  as a retracted position. Switch  360  delivers a signal to control system  45  indicating whether the button is extended out indicating that the brake ring  180  is in the home position, or pushed in as the retracted position indicating that the brake ring  180  is not in the home position as an indicator of the position of the brake ring  180 , which may correspond to the state of the disconnect lever assembly  260  in its locked or unlocked position(s). Control system  45  evaluates whether the brake ring  180  is in the home position to make operational choices, such as requiring the brake ring  180  to be in the home position to allow normal operation of the hydraulic PTO  5  for delivering power to the industrial equipment  25  ( FIG. 1 ). 
         [0040]    Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the above invention is not limited thereto. It will be manifest that various additions, modifications, and rearrangements of the features of the present invention may be made without deviating from the spirit and the scope of the underlying inventive concept.