Abstract:
For providing a lift linkage with easy mounting operation, this invention provides a lifting link mechanism which lifts a mower deck comprising: a front bracket attached to a front portion of the mower deck, a front link coupled to the front bracket, a rear bracket attached to a rear portion of the mower deck, and a rear link coupled to the rear bracket, wherein a protrusion formed in the rear link is fit into a notch portion of the roar bracket and at least the rear link is coupled in a rotatable manner about the protrusion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit to U.S. Provisional Application No. 61/892,575, filed on Oct. 18, 2013 which is incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates a lifting link mechanism. 
         [0004]    2. Background Art 
         [0005]    Conventionally, the tractor having a mower deck is known. Such a tractor has a lifting linkage and vertically movably mower deck. Usual lifting linkages have been designed to suspend the mower deck with the rear link and the front link (for example, see JP 2006-149335 A). 
         [0006]    By the way, the front and the rear link are pivotally connected to the bracket of the mower deck. To be more specific, the front link is connected rotatably around the pin by a pin inserted into the shaft holes in the condition matching the shaft hole of the bracket and the shaft hole of the front link. Similarly, the rear link is connected rotatably around the pin by a pin inserted into the shaft holes in the condition matching the shaft hole of the bracket and the shaft hole of the rear link. Therefore, the lifting linkage has a problem that it is impossible to insert the pin when the shaft holes to be matched are not matched even slightly. That is, such a lift linkage has a problem that mounting operation of the mower deck is difficult. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    Embodiments disclosed herein aim at providing a lift linkage with easy mounting operation. 
         [0008]    In one embodiment, a lifting link mechanism liftable a mower deck is disclosed, comprising: a front bracket attached to a front portion of the mower deck, a front link coupled to the front bracket, a rear bracket attached to a rear portion of the mower deck, and a rear link coupled to the rear bracket, wherein a protrusion formed in the rear link is fit into a notch portion of the rear bracket and at least the rear link is coupled in a rotatable manner about the protrusion. 
         [0009]    In one embodiment, the protrusion is in parallel with the left and right direction, the notch portion is formed to be parallel or approximately parallel with the front and rear direction, and the rear link is coupled in a rotatable manner about the protrusion. 
         [0010]    In one embodiment, the rear link is a plate member has the protrusions formed on each of the left and right surfaces, the rear bracket is composed with two plate members which is formed the notch portion and is arranged in parallel with one another, and the rear link is inserted between the two plate members of the rear bracket with the left and the right protrusions fit along the left and the right notches and is coupled in a rotatable manner about the e protrusion. 
         [0011]    In one embodiment, the lifting link mechanism further comprises: a front wheel bracket attached to the front portion of the mower deck, and a rear wheel bracket attached to the rear portion of the mower deck, wherein the front and the rear wheel brackets are integrated by rib disposed on the upper side of the mower deck. 
       Advantageous Effects 
       [0012]    In one embodiment, the protrusion formed in the rear link is fit into the notch portion of the rear bracket and at least the rear link is coupled in a rotatable manner about the protrusion. Thus process inserting the pin with the state matching the holes is omitted. 
         [0013]    In one embodiment, the rear link is coupled in a rotatable manner about the protrusion along with the notch portion. Thus the mower mounting operation is easy because the rear link and the rear bracket are coupled suitably by moving the mower deck in front-back direction. 
         [0014]    In one embodiment, the rear link is inserted between the two plate members of the rear bracket with the left and the right protrusions fit along the left and the right notches and is coupled in a rotatable manner about the protrusion. Thus the mower mounting operation is easier because the mower deck is mounted suitably without being off to the left and right. 
         [0015]    In one embodiment, the front and the rear wheel brackets are integrated by rib disposed on the upper side of the mower deck. Thus operation for the assembling the mower deck is easy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         [0016]      FIG. 1  is a diagram showing a tractor. 
           [0017]      FIG. 2  is a diagram showing a mower deck and a lifting link mechanism of the same. 
           [0018]      FIG. 3  is a view in a direction of an arrow Fa shown in  FIG. 2 . 
           [0019]      FIG. 4A and 4B  are diagrams showing operation modes of the lifting link. 
           [0020]      FIG. 5  is an enlarged view of a region R shown in  FIG. 2 . 
           [0021]      FIG. 6  is a view in a direction of an arrow Fb shown in  FIG. 5 . 
           [0022]      FIG. 7  is a view in a direction of an arrow Fc shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    First, a tractor  100  is briefly described. 
         [0024]      FIG. 1  shows the tractor  100 . In the figure, the front and rear direction and the upper and lower direction of the tractor  100  are indicated. 
         [0025]    The tractor  100  mainly includes a frame  1 , an engine  2 , a transmission  3 , a front axle  4 , and a rear axle  5 . The tractor  100  further includes a mower deck  6 . 
         [0026]    The frame  1  serves as the main structure for the tractor  100 . The engine  2  and the like described below are attached to the frame  1 . 
         [0027]    The engine  2  converts energy obtained by burning a fuel into rotational movement. When an operator operates an acceleration lever, the engine  2  changes the driving state in accordance with the operation. The engine  2  maintains the rotational speed at constant level even when the load changes. 
         [0028]    The transmission  3  switches between forward and backward movement of the tractor  100  and shifts the speed of the tractor  100 . When the operator operates a shift lever, the operation state of the transmission  3  changes in accordance with the operation. The transmission  3  includes a hydromechanical continuously variable transmission (HMT or I-HMT) as a transmission device. 
         [0029]    The front axle  4  transmits the rotational energy from the engine  2  to front tires  41 . The rotational energy from the engine  2  is input to the front axle  4  through the transmission  3 . The front axle  4  is disposed next to a steering device. When the operator operates a handle, the steering device changes a steering angle of the front tires  41  in accordance with the operation. 
         [0030]    The rear axle  5  transmits the rotational energy from the engine  2  to rear tires  51 . The rotational energy from the engine  2  is input to the rear axle  5  through the transmission  3 . The rear axle  5  is provided with a PTO output mechanism. The PTO output mechanism inputs the rotational energy to an implement, which is the mower deck  6  in the tractor  100 . 
         [0031]    The mower deck  6  rotates a blade to perform lawn mowing and the like. The rotational energy from the engine  2  is input to the mower deck  6  through the PTO output mechanism. The mower deck  6  is suspended by a lifting link mechanism  7 . When the operator operates a lever  61 , the lifting link mechanism  7  raises and lowers the mower deck  6  in accordance with the operation. 
         [0032]    Next, the lifting link mechanism  7  is described in detail. 
         [0033]      FIG. 2  shows the mower deck  6  and the lifting link mechanism  7  of the same.  FIG. 3  is a view in the direction of an arrow Fa shown in  FIG. 2 . In the figure, the front and rear direction, the left and right direction, and the upper and lower direction of the tractor  100  are indicated. 
         [0034]    The lifting link mechanism  7  mainly includes a front bracket  71 , front links  72 , rear brackets  73 , and rear links  74 . The lifting link mechanism  7  according to the embodiment of the present invention further includes control links  75 , control arms  76 , and a control rod  77 . The components are described in detail below. 
         [0035]    The lifting link mechanism  7  includes a single front bracket  71  mainly including two plate members  71 P. One plate member  71 P is arranged in parallel with the other plate member  71 P and has a rear end portion welded on a front portion of the mower deck  6 . Thus, the front bracket  71  is attached on the front portion of the mower deck  6 . The two plate members  71 P forming the front bracket  71  have a shaft hole at the same position. A pin P 1  is inserted in the shaft hole. 
         [0036]    The lifting link mechanism  7  includes two front links  72 . Each front link  72  mainly includes a single rod member  72 R. One rod member  72 R is arranged in parallel with the other rod member  72 R, and has one end portion coupled to the plate member  71 P. Thus, the front link  72  is coupled to the front bracket  71 . Specifically, the front link  72  is coupled to the front bracket  71 , while being rotatable about the pin P 1 , with a shaft hole formed in a clevis of the front link  72  overlapping the shaft hole of the front bracket  71 , and the pin P 1  being inserted in the shaft holes. The other end portion of the front link  72  is supported by a pin P 2  in a rotatable manner. The pin P 2  is inserted into a bracket attached to the frame  1 . 
         [0037]    The lifting link mechanism  7  includes two rear brackets  73  each mainly including two plate members  73 P. One plate member  73 P is arranged in parallel with the other plate member  73 P, and has a front end portion welded to a rear portion of the mower deck  6 . Thus, the rear bracket  73  is attached to the rear portion of the mower deck  6 . The two plate members  73 P forming the rear bracket  73  have a notch  73   n  at the same position (see  FIGS. 5 ,  6 , and  7 ). A protrusion  74   p  formed in the rear link  74  is fit into the notch portion  73   n  (see  FIGS. 5 ,  6 , and  7 ). 
         [0038]    The lifting link mechanism  7  includes two rear links  74  each mainly including a single plate member  74 P. One plate member  74 P is arranged in parallel with the other plate member  74 P, and has one end coupled to the plate member  73 P. Thus, the rear link  74  is coupled to the rear bracket  73 . Specifically, the rear link  74  is coupled to the rear bracket  73  with the protrusion  74   p  formed in the rear link  74  fit in the notch portion  73   n  of the rear bracket  73 . Thus, the rear link  74  is rotatable about the protrusion  74   p  (see  FIGS. 5 ,  6 , and  7 ). The rear link  74  has the other end supported by a pin P 3  in a rotatable manner. The pin P 3  is inserted into the bracket attached to the frame  1 . 
         [0039]    The lifting link mechanism  7  includes two control links  75 . Each control link  75  mainly includes a single rod member  75 R. One rod member  75 R is arranged in parallel with the other rod member  75 R, and has one end portion coupled to the plate member  74 P. Thus, the control link  75  is coupled to the rear link  74 . Specifically, the control link  75  is supported to the rear link  74 , while being rotatable about a pin P 4 , with a shaft hole formed in a clevis of the control link  75  overlapping the shaft hole of the rear link  74 , and the pin P 4  being inserted in the shaft holes. The other end of the control link  75  is supported by a pin P 5  in a rotatable manner. The pin P 5  is inserted into the control arm  76  fixed on a center rod  76 S. 
         [0040]    The lifting link mechanism  7  includes two control arms  76  each mainly including a single plate member  76 P. One plate member  76 P is arranged in parallel with the other plate member  76 P, and has one end portion coupled to the rod member  75 R. Thus, the control arm  76  is coupled to the control link  75 . Specifically, the control arm  76  is coupled to the control link  75 , while being rotatable about the pin P 5 , with a shaft hole thereof overlapping the shaft hole of the control link  75 , and the pin P 5  being inserted in the shaft holes. The other end of the control arm  76  is fixed to the center rod  76 S supported in a rotatable manner on the bracket attached to the frame  1 . 
         [0041]    The lifting link mechanism  7  includes a single control rod  77  mainly including a single rod member  77 R. The rod member  77 R extends approximately in parallel with the front and rear direction, and has one end portion coupled to the center rod  76 S. Thus, the control rod  77  is coupled to the center rod  76 S (coupled to the control arm  76  through the center rod  76 S). Specifically, the control rod  77  is coupled to the center rod  76 S, while being rotatable about a pin P 6 , with a shaft hole formed in a clevis of the control rod  77  overlapping a shaft hole of the center rod  76 S, and the pin P 6  being inserted in the shaft holes. The other end of the control rod  77  is supported by a pin P 7  in a rotatable manner. The pin P 7  is inserted into a bracket supporting the lever  61 . 
         [0042]    Specific operation modes of the lifting link mechanism  7  are described below in detail. 
         [0043]      FIG. 4A  shows a state where the mower deck  6  is lowered.  FIG. 4B  shows a state where the mower deck  6  is raised. Arrows in the figures indicate the operation directions of the components. 
         [0044]    The operator performs an operation to lower the mower deck  6  before performing the lawn mowing and the like. The operation mode in a case where the mower deck  6  is lowered is described below by referring to  FIG. 4A . 
         [0045]    First, the operator pulls up the lever  61 . Thus, the control rod  77  is pushed forward and rotates the center rod  76 S. Thus, the control arm  76  fixed on the center rod  76 S is also rotated, so that the control link  75  is pushed down. Here, the control link  75  rotates the rear link  74  downward. Thus, the mower deck  6  is lowered to a predetermined position. The front link  72  is rotated downward by the rotation of the rear link  74 . Therefore, the mower deck  6  is lowered while being in parallel with the ground. 
         [0046]    After performing the lawn mowing and the like, the operator performs an operation of raising the mower deck  6 . The operation mode in a case where the mower deck  6  is raised is descried below by referring to  FIG. 4B . 
         [0047]    First, the operator pushes down the lever  61 . Thus, the control rod  77  is pulled backward to rotate the center rod  76 S. Thus, the control arm  76  fixed to the center rod  76 S is also rotated, so that the control link  75  is pulled upward. Here, the control link  75  rotates the rear link  74  upward. Thus, the mower deck  6  is raised to a predetermined position. The front link  72  is rotated upward by the rotation of the rear link  74 . Thus, the mower deck  6  is raised while being in parallel with the ground. 
         [0048]    Next, a feature of the lifting link mechanism  7  and its effect will be described. 
         [0049]    The main feature of the lifting link mechanism  7  is that the protrusion  74   p  is disposed on the rear link  74 , the notch  73   n  is disposed on the rear bracket  73 , and the rear link  74  and the rear bracket  73  are coupled with one another through the protrusion  74   p  and the notch  73   n  (see  FIGS. 5 ,  6 , and  7 ). Specifically, the protrusion  74   p  disposed on the rear link  74  is fit in the notch  73   n  disposed on the rear bracket  73  to be engaged therewith, and the coupling is achieved. 
         [0050]    In such a structure, the rear link  74  is coupled, while being rotatable about the protrusion  74   p,  with the protrusion  74   p  disposed on the rear link  74  fit in the notch  73   n  of the rear bracket  73 . Thus, a step of inserting a pin in overlapping shaft holes is not required, whereby attachment of the mower deck  6  is facilitated. 
         [0051]    As described above, in the lifting link mechanism  7 , the protrusion  74   p  is disposed on the rear link  74  and the notch  73   n  is disposed on the rear bracket  73 , and the rear link  74  and the rear bracket  73  are coupled with one another through the protrusion  74   p  and the notch  73   n.  Alternatively, a protrusion may be disposed on the front link  72  and a notch may be disposed on a front bracket  71 , and the front link  72  and the front bracket  71  may be coupled with one another through the protrusion and the notch. 
         [0052]    Such a structure is described in detail below. 
         [0053]      FIG. 5  is an enlarged view of a region R shown in  FIG. 2 .  FIG. 6  is a view in a direction of an arrow Fb shown in  FIG. 5 .  FIG. 7  is a view taken in a direction of an arrow Fc shown in  FIG. 5 . In the figures, the front and rear direction, the left and right direction, and the upper and lower direction of the tractor  100  are indicated. 
         [0054]    In the lifting link mechanism  7 , the protrusion  74   p  is formed to be parallel with the left and right direction. Specifically, the protrusion  74   p  is a protruding portion formed on each of the left and right surfaces of the plate member  74 P. The protruding portion has the center axis L in parallel with the left and right direction. As described above, the single rear link  74  mainly includes the single plate member  74 P. Thus, the rear link  74  may be regarded as a single plate member  74 P having the protrusions  74   p  respectively disposed on the left and the right surfaces. 
         [0055]    The notch  73   n  is formed to he parallel or approximately parallel with the front and rear direction. Specifically, the notch  73   n  is a thin gap portion formed from the front edge of the plate member  73 P toward the rear. The longitudinal direction of the thin gap portion is parallel or approximately parallel with the front and rear direction. As described above, the single rear bracket  73  mainly includes the two plate members  73 P. The plate members  73 P are arranged in parallel with one another. Thus, the rear bracket  73  may be considered as having a configuration, in which the two plate members  73 P each provided with the notch  73   n  are disposed in parallel with one another. 
         [0056]    In such a structure, the rear link  74  has the protrusion  74   p  fit along the notch  73   n  (see arrow M in  FIG. 7 ), and thus is coupled in a rotatable manner about the protrusion  74   p.  Thus, the rear link  74  and the rear bracket  73  are able to be appropriately coupled to one another by moving the mower deck  6  in the front and rear direction. Thus, the attachment of the mower deck  6  is even more facilitated. 
         [0057]    Furthermore, the rear link  74  and the rear bracket  73  have the configurations described above, due to the following reason. 
         [0058]    Specifically, the rear link  74  including the single plate member  74 P is inserted into the rear bracket  73  including the two plate members  73 P. Thus, the rear link  74  and the rear bracket  73  are coupled with one another in such a manner as not to be offset from one another in the left and right direction. Specifically, the plate member  74 P of the rear link  74  is guided by the plate member  73 P of the rear bracket  73 , and thus, the rear link  74  and the rear bracket  73  are coupled with one another in such a manner as not to be offset from one another in the left and right direction. 
         [0059]    In such a structure, the rear link  74  is inserted between the two plate members  73 P of the rear bracket  73  with the left and the right protrusions  74   p  fit along the left and the right notches  73   n.  Thus, the rear link  74  is coupled while being rotatable about the protrusions  74   p.  Thus, the rear link  74  and the rear bracket  73  are able to be appropriately coupled with one another without being offset in the left and right direction, by moving the mower deck  6  in the front and rear direction. Thus, the attachment of the mower deck  6  is even more facilitated. 
         [0060]    As described above, in the lifting link mechanism  7 , when the rear link  74  is inserted between the two plate members  73 P of the rear bracket  73 , the left and the right protrusions  74   p  are fit along the left and the right notches  73   n.  The fitting of the protrusion  74   p  is facilitated by chamfering the front edge of the notch  73   n  (when the notch  73   n  has a chamfered like shape) (see two-dot chain line G in  FIG. 7 ). 
         [0061]    Next, another feature of the lifting link mechanism  7  and its effect will be described. 
         [0062]    As shown in  FIGS. 2 and 3 , the lifting link mechanism  7  includes front wheel brackets  78  and rear wheel brackets  79 . 
         [0063]    The front wheel bracket  78  is a structure that supports a front wheel  781  in a rotatable manner. A rear end of the front wheel bracket  78  is welded on a front portion of the mower deck  6 . Thus, the front wheel bracket  78  is attached to the front portion of the mower deck  6 . The front wheel bracket  78  is reinforced by a rib  62  extending on the upper side of the mower deck  6  in the front and rear direction. 
         [0064]    The rear wheel bracket  79  is a structure that supports a rear wheel  791  in a rotatable manner. A front end portion of the rear wheel bracket  79  is welded on a rear portion of the mower deck  6 . Thus, the rear wheel bracket  79  is attached to the rear portion of the mower deck  6 . The rear wheel bracket  79  is reinforced by the rib  62  extending on the upper side of the mower deck  6  in the front and rear direction. 
         [0065]    In the lifting link mechanism  7 , the rib  62  extends forward on the upper side of the mower deck  6 , and is welded on an upper portion of the front wheel bracket  78 . The rib  62  also extends backward on the upper side of the mower deck  6 , and is welded on an upper portion of the rear wheel bracket  79 . The front and rear ends of the rib  62  are respectively welded on the front wheel bracket  78  and the rear wheel bracket  79 . 
         [0066]    In such a structure, the front and the rear wheel brackets  78  and  79  are coupled with one another through the rib  62  disposed on the upper side of the mower deck  6 . Thus, the front and the rear wheel brackets  78  and  79  are integrated, whereby the assembly of the mower deck  6  is facilitated.