Abstract:
A clutch for selectively driving a mechanism. The clutch includes an engagement member movable between an engaged position for driving the mechanism and a disengaged position. The clutch also includes an actuation assembly having a first member pivotable about a pivot and cooperative with a control element for movement between a retaining position and a release position, and a second member pivotable about the pivot between the retaining position and the release position. The second member extends towards the engagement member in the retaining position for maintaining the engagement member in the disengaged position. The second member is pivotable about the pivot independently of the first member such that the second member is rotatable relative to the first member.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a clutch mechanism for a machine, such as a hay baler. 
         [0002]    More specifically, the present disclosure relates to the clutch mechanism that activates the knotter and twine needles in a baler, such as a square baler for baling hay. 
       SUMMARY 
       [0003]    In one aspect, the disclosure provides a clutch for selectively driving a mechanism. The clutch includes an engagement member movable between an engaged position for driving the mechanism and a disengaged position, and an actuation assembly. The actuation assembly includes a first member pivotable about a pivot and cooperative with a control element for movement between a retaining position and a release position, and a second member pivotable about the pivot between the retaining position and the release position. The second member extends towards the engagement member in the retaining position for maintaining the engagement member in the disengaged position. The second member is pivotable about the pivot independently of the first member such that the second member is rotatable relative to the first member. 
         [0004]    In another aspect, the disclosure provides a clutch for selectively driving a mechanism, the clutch having a dog movable between an engaged position for driving the mechanism and a disengaged position, and a control movable between a retaining position for holding the dog in the disengaged position and a release position for releasing the dog to the engaged position. The clutch includes an actuation assembly having a pivot, the actuation assembly pivotable about the pivot between the retaining position and the release position in response to the control. The actuation assembly includes a first member pivotable about the pivot between the retaining position and the release position and a second member pivotable about the pivot between the retaining position and the release position. The first member is coupled to the control for being moved between the retaining position and the release position. The second member extends towards the dog in the retaining position for holding the dog in the disengaged position. The second member is coupled to the first member at the pivot such that the first and second members are independently pivotable about the pivot such that the actuation assembly is capable of flexing about the pivot to inhibit binding between the dog and the actuation assembly. 
         [0005]    In yet another aspect, the disclosure provides an actuator for engaging and disengaging a clutch mechanism, the clutch mechanism including a clutch engagement member. The actuator includes a first member responsive to a control element for pivotal movement about a pivot point from a first position to a second position, and a second member resiliently couplable to the first member for concurrent pivotal movement with the first member about the pivot point in response to the control element. The second member presents a contact surface and is pivotable relative to the first member about the pivot point in response to interaction between the contact surface and the clutch engagement member. 
         [0006]    The disclosure also provides a clutch for selectively driving a mechanism. The clutch includes a driven rotating member having a driving lug positioned on an inner annular surface and having an outer surface, and a dog movable between an engaged position wherein the dog is driven by the driving lug for driving the mechanism and a disengaged position wherein the dog is disengaged from the driving lug. The clutch also includes an actuation assembly having a pivot and movable between a retaining position for holding the dog in the disengaged position and a release position for releasing the dog to the engaged position. The actuation assembly includes a first member pivotable about the pivot between the retaining position and the release position. The first member has a follower configured to selectively follow the outer surface of the rotating member. The actuation assembly also includes a second member pivotable about the pivot between the retaining position and the release position. The second member extends towards the dog in the retaining position for holding the dog in the disengaged position. The second member is coupled to the first member at the pivot such that the first and second members are independently pivotable about the pivot such that the actuation assembly is capable of flexing about the pivot to inhibit binding between the dog and the actuation assembly. 
         [0007]    Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a partial cutout side view of a machine, such as a baler, having a clutch in accordance with one implementation of the present disclosure. 
           [0009]      FIG. 2  is a partial cutout perspective view of the machine and clutch of  FIG. 1 . 
           [0010]      FIG. 3  is a perspective view of the clutch of  FIG. 1 . 
           [0011]      FIGS. 4-10  are side views of the clutch of  FIG. 1 , shown in various stages of operation. 
           [0012]      FIG. 11  is a perspective view of an actuation assembly portion of the clutch of  FIG. 1 . 
           [0013]      FIG. 12  is an exploded view of the actuation assembly of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other constructions and of being practiced or of being carried out in various ways. Directions such as clockwise and counterclockwise used herein are for illustrative purposes only. 
         [0015]    The disclosure relates to a machine  10 , such as a baler. In the illustrated construction, the disclosure relates to a square hay baler. In other constructions, the disclosure may relate to other types of balers, such as other extrusion type balers or non-extrusion type balers. In yet other constructions, the disclosure may relate to other types of machines, e.g., vehicles, tractors, other types of agricultural machines, forestry machines, mining machines, construction machines, machines for manufacturing, etc. 
         [0016]    Referring to  FIGS. 1-2 , the baler  10  has a series of knotters  12  at generally the top of the baler  10  which cooperate with twine needles  14  that place strands of twine around a finished bale. Some components of the knotters  12  are not shown in  FIG. 2  for simplicity. The knotters  12  form a secure knot in the opposite ends of each twine strand and then cut the twine from the tied bale while retaining the free end of the twine for use in wrapping around the next bale. A bale length sensor  16 , e.g., a star wheel  16 , determines when a bale has reached full length, engages a clutch  18  that drivingly couples the knotters  12  with a rotating drive assembly  20 , and causes the knotters to actuate for one single revolution. After each single revolution, the clutch  18  is disengaged until the next bale reaches the proper length. During each knotter cycle, the needles  14  swing across a bale chamber located inside the baler  10  to present the ends of twine strands to the knotters  12 . In other constructions, the bale length sensor  16  may include other types of mechanical or electronic devices, such as optical sensors, cameras, presence sensors, timers, etc. 
         [0017]    The knotters  12  are supplied operating power through the drive assembly  20 , such as a chain drive assembly, ultimately from the power takeoff (PTO) of a tractor. In other constructions, the baler  10  may have a dedicated power supply, such as an engine. A drive member  22 , which is a component of the drive assembly  20 , is constantly driven to rotate about an axis A, so long as power is being supplied to the baler  10 . Although the drive member  22  is continuously driven, the knotters  12  are not driven unless the clutch  18  is engaged. 
         [0018]    As shown in  FIGS. 2-10 , the clutch  18  includes a cam ring  32  projecting axially outwardly from an axial outer face of the drive member  22  with respect to axis A. The cam ring  32  has an inner, annular surface  34  substantially concentric about the axis A. A driving lug  30  with a contact surface  31  projects radially inwardly from the surface  34 . An external stop  60  extends radially outwardly from an outer annular surface  70  of the cam ring  32  at a fixed angular distance (a) from the driving lug  30  ( FIGS. 4 and 10 ). 
         [0019]    The clutch  18  further includes a dog  26  mounted on a clutch member  28 . The clutch member  28  presents a reset cam surface  62  disposed generally circumferentially about an outer surface of the clutch member  28  and a needle linkage attachment point  44  operably coupled with a needle linkage  46  ( FIGS. 1 and 2 ) secured to the needles  14 . 
         [0020]    The dog  26  includes a biasing member attachment point  36 , a pivot  38 , and an engagement member  40  carrying a follower, such as a roller  41  at a first end and having a retaining portion  48  at a second end. In other constructions, the follower may include a surface or other type of following member. The biasing member attachment point  36 , the roller  41 , and the retaining portion  48  generally form a substantially triangular-shaped dog  26 . The pivot  38  is disposed substantially in line with the engagement member  40  and the biasing member attachment point  36  within the triangular-shaped dog  26 ; however, in other constructions the pivot point  38  may be outside such that the dog  26  is shaped substantially as a  4 -sided polygon. 
         [0021]    The dog  26  is coupled to the clutch member  28  at the pivot  38  and is pivotable between an engaged position ( FIGS. 5-10 ) and a disengaged position ( FIG. 4 ). In the engaged position, the engagement member  40  (and more specifically, the roller  41 ) of the dog  26  rides along the inner annular surface  34  of the cam ring  32  within a substantially circular path of travel of the moving driving lug  30 . When the driving lug  30  meets the roller  41 , the driving lug  30  is drivingly mated with the dog  26  ( FIG. 8 ) such that the clutch member  28  is engaged for actuating the knotters  12  and twine needles  14 . In the disengaged position, the engagement member  40  is lifted radially inward towards the axis A of rotation, creating a clearance so that the driving lug  30  passes under the engagement member  40  without engaging the roller  41  such that the clutch member  28  is disengaged and the knotters  12  and twine needles  14  are not actuated. A biasing member  42  anchored to the clutch member  28  biases the dog  26  to the engaged position. In the illustrated construction, the biasing member  42  includes a spring, such as a coil spring in the form of an extension spring or a compression spring. In other constructions, other types of springs may be employed and in yet other constructions, other types of biasing members may be used, such as elastic members, bands, counter weights, etc. 
         [0022]    The clutch  18  is engaged and disengaged by a control  96  that includes the bale length sensor  16  (see  FIG. 1 ). The bale length sensor  16  is coupled to a trip linkage  50 , which is in turn coupled to an actuation assembly  52  for holding the dog  26  in the disengaged position against the bias of the biasing member  42  until the bale length sensor  16  trips the actuation assembly  52 . 
         [0023]    Referring to  FIGS. 11-12 , the actuation assembly  52  includes a control member  54 , a retaining member  56 , and a flex member  58  disposed between and linking the control member  54  and the retaining member  56 . The control member  54  includes a pivot  64  and a first arm  66  extending generally away from the pivot  64 . The first arm  66  has a stop follower, such as a stop roller  68 , for timing the movement of the dog  26  into the engaged position relative to the driving lug  30 , as will be described in greater detail below. With reference to  FIGS. 2-3 , the stop roller  68  and the outer surface  70  of the cam ring  32  are disposed substantially in the same plane substantially normal to the axis A. The first arm  66  also includes a reset follower, such as a reset roller  72 , for returning the clutch  18  to the disengaged position. With reference to  FIGS. 2-3 , the reset roller  72  and the reset cam surface  62  of the clutch member  28  are disposed in substantially the same plane substantially normal to the axis A. In other constructions, other types of followers may be employed. The first arm  66  also includes a control attachment point  98  at which the actuation assembly  52  is attached to the control  96 . Specifically, the control attachment point  98  is coupled to the trip linkage  50 . A second arm  74  and a third arm  76  of the control member  54  both extend generally away from the pivot point  64  in directions different from the first arm  66 . The third arm  76  is coupled to a biasing member  78  for biasing the actuation assembly  52  to a released position, which will be described in greater detail below. 
         [0024]    The flex member  58  is coupled to the control member  54  at the pivot  64 . The pivot  64  is also the pivot point for the actuation assembly  52  as a whole, which pivots about a pivot axis B. 
         [0025]    The flex member  58  includes a first arm  80  and a second arm  82 , each extending generally away from the pivot  64  in substantially different directions. A biasing member  84  couples the first arm  80  of the flex member  58  to the second arm  74  of the control member  54  and biases the arms  80 ,  74  together such that the flex member  58  resiliently follows the control member  54  and the control member  54  resiliently follows the flex member  58  when one or the other pivots about the axis B. The biasing member  84  allows for resilience and some relative movement between the flex member  58  and the control member  54 , e.g., in response to external stresses or accidental movement, as will be described in greater detail below. Thus, while the flex member  58  generally follows the pivoting movement of the control member  54  and vice versa, some relative pivoting movement is allowed between the flex member  58  and the control member  54  about the pivot  64 . The biasing member  84  preferably includes a compression spring disposed between washers on a rod coupled between the first arm  80  and the second arm  74 , as shown in  FIGS. 2-3  and  11 - 12 . In other constructions, other biasing members  84  may be employed, as discussed above. For example, as shown in  FIGS. 4-10 , an extension spring may be employed. A counter weight  86  coupled to a distal end of the first arm  80  of the flex member  58  provides redundancy to the biasing member  84  such that the control member  54  and the flex member  58  are biased to follow each other as described above. The counter weight  86  also biases the actuation assembly  52  to a retaining position, which will be described in greater detail below. 
         [0026]    The retaining member  56  is pivotably coupled to a distal end of the second arm  82  of the flex member  58  at a pivot  88 . The retaining member  56  includes an arcuate aperture  90  and a disengagement surface  91  for disengaging the clutch  18 . A pin  92  fixed to the second arm  82  of the flex member  58  is received in the arcuate aperture  90 . The retaining member  56  is pivotable about an angular range defined by the arcuate aperture  90  and is biased by a biasing member  94  towards the dog  26 . The biasing member  94  includes a compression spring coupled between the retaining member  56  and the flex member  58 ; however, in other constructions, the biasing member  94  may comprise other forms as described above. 
         [0027]    The clutch  18  is configured such that the external stop  60  is disposed proximate the stop roller  68  when the driving lug  30 , and more specifically the contact surface  31 , is disposed proximate the engagement member  40 , and more specifically the roller  41 , of the dog  26 , e.g., an engagement location where the driving lug  30  would meet the roller  41 . This positional relationship determines the angular distance (α). In other words, the angular distance (α) is the angular distance between the stop roller  68  and the driving lug  30  when the contact surface  31  is disposed proximate the roller  41 . As illustrated (see  FIGS. 4 and 10 ), the angle α is between about 90 and about 180 degrees, and more specifically is between about 130 and about 140 degrees, and more specifically is about 135 degrees. In other constructions, the angle α may be different but is determined by the relative locations of the stop roller  68  and the engagement member  40  as discussed above. 
         [0028]    In operation, the trip linkage  50  holds the actuation assembly  52  in the retaining position against the bias of the biasing member  78  while the bale is being formed in the baler  10 . The retaining member  56  is maintained against retaining portion  48  of the dog  26  and positions the dog  26  in the disengaged position against the force of the biasing member  42 . The retaining member  56  resiliently engages the retaining portion  48  of the dog  26  due to the biasing member  94  and the give provided by the retaining member  56  being pivotably coupled to the flex arm  58 . During engagement with the retaining portion  48 , the retaining member  56  may be in a partially flexed state as the forces of the biasing members  42  and  94  act against each other. As the bale is being formed, the chain  24  is continuously operating such that the drive member  22  is continuously rotating. The driving lug  30  thus advances in a circular path of travel about the axis A in a counterclockwise direction. To the extent the dog  26  remains in the disengaged position ( FIG. 4 ), driving lug  30  passes radially outward from the roller  41  of the dog  26  during each revolution and the clutch  18  remains disengaged. 
         [0029]    When the bale is formed, i.e., has reached a predetermined length as determined by the bale length sensor  16 , the trip linkage  50  moves to release the actuation assembly  52  to the released position such that the biasing member  78  pulls the actuation assembly  52  about the pivot  64  in a counterclockwise direction. Due to this pivoting, the retaining member  56  separates from the dog  26 , permitting the biasing member to inwardly pull the attachment point  36  such that the engagement member  40  (and the roller  41 ) of the dog  26  rotates about the pivot  38  towards the inner annular surface  34  of the drive member  22  ( FIG. 5 ). As the retaining member  56  separates from the dog  26 , the biasing member  94  forces the retaining member  56  to a fully extended position (counterclockwise). When the driving lug  30  contact surface  31  reaches the roller  41  ( FIG. 7 ), the driving lug  30  drives the dog  26 , which in turn drives the clutch member  28  through one operating cycle of 360 degrees to operate the aforementioned needles  14 . During the operating cycle, the reset cam surface  62  engages the reset roller  72  ( FIG. 10 ), which pivots the actuation assembly  52  clockwise about the pivot  64  to dispose the retaining member  56  back into the path of the retaining portion  48  of the dog  26  when the dog  26  returns at the end of its revolution. Re-engagement of the retaining member  56  with the retaining portion  48  rotates the dog  26  clockwise about the pivot  38  into its disengaged position, disengaging the clutch  18 . The driving lug  30  continues along its path of travel. 
         [0030]    In the event that the bale length sensor  16  attempts to release the actuation assembly  52  when the driving lug  30  is just about to pass under the dog  26  (e.g., near the engagement position as shown in  FIG. 4 ), release of the actuation assembly  52  is inhibited by the external stop  60  to deter a poor connection between the driving lug  30  and the dog  26 . As discussed above, the external stop  60  is disposed proximate the stop roller  68  by design in this condition. Specifically, in this position the external stop  60  engages the stop roller  68 , thereby retaining the actuation assembly  52  in the retaining position regardless of activation of the trip linkage  50  and allowing the driving lug  30  to pass under the dog  26  without engagement. Once the external stop  60  clears the stop roller  68  ( FIG. 5 ), the actuation assembly  52  is free to release as described above. That is, when the driving lug  30  makes another revolution and approaches the engagement member  40  of the dog  26  ( FIG. 6 ), engagement will occur as described above if the trip linkage  50  has moved to release the actuation assembly  52 . 
         [0031]    Typically, when the dog  26  becomes engaged with the driving lug  30 , the retaining portion  48  clears the actuation assembly  52 . However, in some instances, the retaining portion  48  may run into the actuation assembly  52 . For example, when engagement between the stop roller  68  and the external stop  60  drives the control member  54  clockwise, the flex member  58  and the retaining member  56  are also driven clockwise, potentially driving the flex member  58  and/or the retaining member  56  into the engagement member  40  of the dog  26 . Other possible reasons for interference between the dog  26  and the actuation assembly  52  include tolerance build-up, timing, vibrations, or other reasons. In any of these instances, to inhibit lock-up, binding, or damage to the components as the dog  26  is driven, the actuation assembly  52  flexes about the pivot  64  and/or the pivot  88  to make way for the dog  26  ( FIGS. 7-8 ). Specifically, the flex member  58  pivots counterclockwise with respect to the control member  54 , i.e., such that the first arm  80  of the flex member  58  moves away from the second arm  74  of the control member  54 . The control member  54  may not be able to follow the flex member  58  in these instances due to engagement between the stop roller  68  and the external stop  60  inhibiting pivoting movement in that direction (counterclockwise). Thus, the flex member  58  allows the actuation assembly  52  to flex in on itself about the pivot  64  ( FIGS. 7-8 ) to inhibit lock-up, binding, damage, etc. When the dog  26  is completely clear of the actuation assembly  52 , then the biasing member  84  and/or the weights  86  allow the control member  54  and the flex member  58  to return to equilibrium to their relative angular positions with respect to each other, i.e., a neutral position ( FIGS. 4-6  and  9 - 10 ). Furthermore, the retaining member  56  may also flex in these conditions. For example, the retaining member  56  may rotate clockwise about the pivot  88  with respect to the flex member  58  to make way for the driven dog  26 , thereby inhibiting lock-up, binding, damage, etc. 
         [0032]    Thus, the disclosure provides, among other things, an actuation assembly for engaging and disengaging a clutch, the actuation assembly being capable of flexing to avoid binding with other driven components. While the above describes example embodiments of the present disclosure, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present disclosure as defined in the appended claims.