Abstract:
This disclosure pertains to a post driver apparatus of simplified and compact construction. The apparatus can be easily attached to a vehicle equipped with a universal quick attach hitch and having auxiliary hydraulics, for example a farm or construction vehicle. The apparatus includes a hydraulic motor that is driven by the auxiliary hydraulics of the vehicle to which the apparatus is attached. The hydraulic motor rotates a drive wheel of the apparatus which is operatively connected with a weight piston of the apparatus. Rotation of the drive wheel lifts and then drops the weight piston on each rotation of the drive wheel. With the apparatus positioned on the top end of a post, each time the weight piston is dropped it impacts the top of the post and drives the post downwardly. The apparatus is equipped with a safety feature that prevents rotation of the drive wheel from operatively raising the weight piston until the apparatus is positioned on top of a post and exerts a force on the top end of the post.

Description:
FIELD 
       [0001]    This disclosure pertains to a post driver apparatus. More specifically, this disclosure pertains to a post driver apparatus of simplified and compact construction. The apparatus can be easily attached to a vehicle equipped with a universal quick attach hitch and having auxiliary hydraulics, for example a farm or construction vehicle. The apparatus includes a hydraulic motor that is driven by the auxiliary hydraulics of the vehicle to which the apparatus is attached. The hydraulic motor rotates a drive wheel of the apparatus which is operatively connected with a weight piston of the apparatus. Rotation of the drive wheel lifts and then drops the weight piston on each rotation of the drive wheel. With the apparatus positioned on the top end of a post, each time the weight piston is dropped it impacts the top of the post and drives the post downwardly. The apparatus is equipped with a safety feature that prevents rotation of the drive wheel from operatively raising the weight piston until the apparatus is positioned on top of a post and exerts a force on the top end of the post. 
       BACKGROUND 
       [0002]    There are currently available various different types of post driver apparatus. Their constructions and operations are basically the same. They function by driving or dropping a hammer or weight against a top end of a post, and thereby driving the bottom end of the post into the ground. 
         [0003]    Many of the current post driver apparatus have complex and/or cumbersome constructions. Their constructions make the apparatus difficult to position on a post and difficult to operate to drive the post. Many types of post drivers directly strike the top of the post with the weight which causes damage to the post while driving. In addition, post drivers that directly strike the top of the post with the weight do not securely hold the post while driving, which permits the post to move leading to “loose” posts that are not plumb. 
       SUMMARY 
       [0004]    The post driver apparatus of this disclosure has a simplified construction that is easy to maneuver and operate. The apparatus can be easily attached by a universal quick attach hitch to a vehicle having an auxiliary hydraulic circuit. For example, the apparatus can be easily attached to the lift arms of a skid-steer. 
         [0005]    The apparatus has a cylindrical housing with opposite top and bottom ends. A hollow interior bore extends through the housing between the top and bottom ends. A cylindrical sidewall surrounds the interior bore and extends along a length of the housing. A top wall of the housing closes over the hollow interior bore at the housing top end. A bottom wall having an opening extends over the hollow interior bore at the housing bottom end. The bottom wall is formed as an annular rim or flange that extends from the housing into the interior bore. The annular rim configuration of the bottom wall surrounds the opening. The opening communicates an exterior environment of the housing with the hollow interior bore through the opening. The housing also has a slot through the sidewall of the housing. The slot extends along the length of the housing and communicates the exterior environment of the housing with the hollow interior bore through the slot. 
         [0006]    A strike plate is positioned in the housing interior bore. The strike plate lays on the annular rim bottom wall and over the opening in the bottom wall. The strike plate is free to move upwardly and downwardly a short distance in the interior bore. 
         [0007]    A weight piston is mounted in the interior bore for reciprocating movement of the piston between a lower position and an upper position of the piston in the interior bore. In the lower position of the piston, the piston lays on the strike plate with the strike plate in turn laying on the bottom wall of the housing. The piston has a plurality of projections on a side of the piston. The plurality of projections extend through the slot in the sidewall of the housing. 
         [0008]    A spring is positioned in the housing interior bore between the piston and the top wall of the housing. The spring urges the piston downwardly toward the lower position of the piston in the interior bore. 
         [0009]    A shaft is mounted on the housing for rotation of the shaft. The shaft is an output shaft of a hydraulic motor. The hydraulic motor is mounted to the exterior of the housing with the shaft traversing the slot in the housing sidewall. A pair of hydraulic hoses connect the hydraulic motor to the auxiliary hydraulic circuit of the vehicle with which the apparatus is used. 
         [0010]    A drive wheel is attached to the shaft for rotation of the drive wheel with rotation of the shaft. The drive wheel is comprised of a pair of spaced, side by side plates. The plates have circular peripheral edges that define a circular periphery of the drive wheel. 
         [0011]    A plurality of pins are mounted on the drive wheel between the pair of plates. The plurality of pins are spatially arranged in an arc along the circular peripheral edges of the plates. The plurality of pins are arranged around less than one quarter of the drive wheel periphery. 
         [0012]    To operate the apparatus, the auxiliary hydraulics of the vehicle to which the apparatus is attached are activated, causing the hydraulic fluid to cycle through the hydraulic motor. This results in the hydraulic motor rotating the shaft, which in turn rotates the drive wheel. With the piston positioned in the lower position of the piston in the interior bore, the rotation of the drive wheel causes the plurality of pins to pass over the plurality of projections on the piston and not engage with the plurality of projections. 
         [0013]    The apparatus is then moved by the vehicle to the post to be driven by the apparatus. The vehicle positions the apparatus over the top end of the post and then lowers the apparatus onto the post. The top end of the post passes through the opening in the bottom wall of the housing and engages against the strike plate. Further downward movement of the apparatus onto the top end of the post causes the post to push the strike plate upwardly, which in turn pushes the piston upwardly and begins compression of the spring. 
         [0014]    With the piston moved above the lower position of the piston, the projections on the piston are moved upwardly to a position where they can be engaged by the plurality of pins on the drive wheel. The rotation of the drive wheel causes the pins to come into engagement with the plurality of projections on the piston. Further rotation of the drive wheel causes the plurality of pins to push upwardly on the plurality of projections and move the piston upwardly through the interior bore from the strike plate adjacent the bottom end of the housing toward the top end of the housing. This movement of the piston further compresses the spring. Still further rotation of the drive wheel causes the plurality of pins to disengage from the plurality of projections, releasing the piston from its operative connection with the drive wheel. The disengagement of the plurality of pins from the projections causes the weight of the piston and the force of the spring to move the piston downwardly toward the housing bottom wall. Engagement of the piston against the strike plate exerts a force of impact on the top end of the post, driving the bottom end of the post into the ground. The continued rotation of the drive wheel sequentially raises and then releases the piston for downward movement and impact with the strike plate and the top end of the post. This cycle is repeated six times per second with the vehicle auxiliary hydraulic circuit cycling at 15 gallons per minute. 
         [0015]    With the post driven into the ground to its desired depth, the vehicle lifts the apparatus from the driven post. Lifting the apparatus from the post causes the piston to be moved to the lower position of the piston in the interior bore. This in turn disengages the drive wheel pins from the piston projections. The vehicle is then operated to move the apparatus to the next post location. 
         [0016]    Further features of the apparatus are disclosed in the following detailed description of the apparatus and the drawing figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of the post driver apparatus of this disclosure attached to a quick attach plate assembly that enables the apparatus to be attached to a vehicle having a universal quick attach hitch and auxiliary hydraulics. 
           [0018]      FIG. 2  is a representation of the apparatus of this disclosure being attached to the quick attach plate assembly. 
           [0019]      FIG. 3  is a representation of a perspective view of the left side of the apparatus removed from the quick attach plate assembly. 
           [0020]      FIG. 4  is a representation of a perspective view of the right side of the apparatus shown in  FIG. 5 . 
           [0021]      FIG. 5  is a representation of an exploded view of the apparatus component parts. 
           [0022]      FIG. 6  is a representation of the apparatus sidewall removed from the apparatus and showing an opposite side of the sidewall not shown in  FIG. 5 . 
           [0023]      FIG. 7  is a representation of a perspective view of a foot of the apparatus removed from the apparatus. 
           [0024]      FIG. 8  is a representation of a side cross-section view of a piston of the apparatus removed from the apparatus. 
           [0025]      FIG. 9  is a representation of a side view of a drive wheel of the apparatus with the component parts of the drive wheel disassembled from the drive wheel. 
           [0026]      FIG. 10  is a representation of an end view of the drive wheel. 
           [0027]      FIGS. 11A-11D  are representations of side cross-section views of the apparatus during one cycle of operation of the apparatus. 
       
    
    
     DESCRIPTION 
       [0028]      FIG. 1  is a representation of the post driver apparatus  10  of this disclosure attached to a quick attach plate assembly  12 . The quick attach plate assembly  12  is employed to easily attach the apparatus  10  to a vehicle that is equipped with a universal quick attach hitch and auxiliary hydraulics. For example, the plate assembly  12  could be used to attach the apparatus  10  to the lift arms of a skid-steer.  FIG. 2  is a representation of the process of attaching the apparatus  10  to the quick attach plate assembly  12 . As represented in  FIG. 2 , the plate assembly  12  has a pair of brackets  14 . The brackets are the same and each bracket has a pair of parallel flanges  16 . The flanges have aligned pairs of holes  18  through the flanges. The apparatus  10  can be quickly attached to either of the brackets  14  by a pair of pins  20  that are inserted through aligned holes of the apparatus  10  and either of the brackets  14 . The pins  20  are secured in place once installed by cotter pins or rue clips  22 . The quick attach plate assembly  12  is only one means of easily attaching the apparatus  10  to the vehicle with which the apparatus is to be used. Other attachment means may be used and therefore the quick attach plate assembly  12  will not be further described herein. 
         [0029]    Referring to  FIG. 5 , the apparatus  10  has a housing with a generally cylindrical configuration defined by a cylindrical sidewall  24 .  FIG. 6  shows the sidewall  24  removed from the apparatus  10 . The view of the sidewall  24  in  FIG. 6  is an opposite side of the sidewall  24  shown in  FIG. 5 . The sidewall  24  extends along a length of the housing between a top end  26  of the housing and a bottom end  28  of the housing. A hollow interior bore  30  extends through the housing between the housing top end  26  and the housing bottom end  28 . The cylindrical sidewall  24  surrounds the interior bore  30 . The housing also includes a circular top wall  32  secured to the cylindrical sidewall  24  at the top end  26  of the housing. An annular rim  34  extends around the bottom of the cylindrical sidewall  24 . A slot  36  is formed through the cylindrical sidewall  24  just above the annular rim  34 . The slot  36  extends upwardly from the annular rim  34  to the top wall  32  of the housing. The slot  36  communicates an exterior environment of the housing with the interior bore  30 . 
         [0030]    A cylindrical foot  38  is secured to the annular rim  34  by a plurality of nut and bolt fasteners  40 .  FIG. 7  is a perspective view of the foot  38  removed from the apparatus  10 . The cylindrical foot  38  defines the bottom of the housing and a bottom of the interior bore  30 . An annular flange or annular bottom wall  42  extends inwardly into the interior bore at an intermediate portion of the cylindrical foot  38 . The annular bottom wall  42  surrounds an opening  44  to the interior bore  30 . The opening  44  communicates the exterior environment of the housing with the interior bore  30 . A lower cylindrical portion  46  of the cylindrical foot  38  extends downwardly from an interior edge of the opening  44 . 
         [0031]    A strike plate  50  is positioned in the housing interior bore  30  adjacent the housing bottom end  28 . The strike plate  50  has a peripheral edge that conforms to the interior surface of the cylindrical foot  38 . This configuration of the strike plate peripheral edge enables the strike plate  50  to move through the interior bore  30  between the annular bottom wall  42  and the annular rim  34 . When the apparatus  10  is not in use, the strike plate  50  lays on the annular bottom wall  42  over the opening  44  to the housing interior bore. 
         [0032]    A piston  52  is mounted in the housing interior bore  30  for reciprocating movements of the piston in the interior bore.  FIG. 8  is a side cross-section view of the piston  52  removed from the apparatus  10 . The piston  52  has a cylindrical sidewall  54  and a circular bottom head surface  56  that surround a hollow interior  58  of the piston. In a lower position of the piston  52  in the housing interior bore  30 , the piston head surface  56  lays on the strike plate  50  which in turn lays on the annular bottom wall  42  of the housing. The piston has a plurality of projections  60  that project from the piston sidewall  54 . The projections  60  are arranged in line on the piston sidewall  54  and project through the housing slot  36 . In the embodiment of the apparatus shown in the drawing figures, there are three projections  60 . However, for different sizes of apparatus  10  there could be more or fewer projections. 
         [0033]    A coiled spring  62  is mounted in the housing interior bore  30 . The spring  62  is positioned between the piston  52  and the housing top wall  32 . A majority of the spring  62  is contained in the piston interior  58 . The length of the spring  62  is such that, with one end of the spring engaging against the housing top wall  32  the opposite end of the spring pushes the piston head surface  56  against the strike plate  50  with the strike plate laying on the housing annular bottom wall  42 . 
         [0034]    A support structure  64  is attached to the exterior of the housing sidewall  24 . As described earlier, the support structure  64  can be used to attach the apparatus  10  to the quick attach plate assembly  12 . Alternatively, the support structure  64  can be used to attach the apparatus  10  to a vehicle having auxiliary hydraulics in any other equivalent manner. 
         [0035]    A hydraulic motor  66  is attached to the support structure  64 . The motor  66  has an output shaft  68  that extends from the motor and into the support structure  64 . As is conventional, the hydraulic motor  66  has a supply hose  70  and a return hose  72 . The hoses  70 ,  72  are connected to fittings of the vehicle with which the apparatus  10  is used that communicate the hydraulic motor  66  with the auxiliary hydraulic circuit of the vehicle. On operation of the auxiliary hydraulic circuit, hydraulic fluid is cycled through the motor  66  which in turn causes rotation of the motor shaft  68 . 
         [0036]    A drive wheel  74  is connected to the shaft  68  for rotation of the drive wheel with rotation of the shaft.  FIGS. 9 and 10  show details of the drive wheel  74 . The drive wheel  74  is comprised of a pair of spaced plates  76 ,  78  having circular peripheral edges. The plates  76 ,  78  are spaced from each other by a plurality of pin and roller assemblies  80  connected between the plates. Each pin and roller assembly  80  includes a pin and a hardened roller mounted for rotation on the pin. As shown in the drawing figures, the pin and roller assemblies  80  are arranged in an arc around a portion of the peripheral edges of the drive wheel plates  76 ,  78 . The plurality of pin and roller assemblies  80  extend around only a fraction of the drive wheel periphery. In the embodiment shown in the drawing figures, the plurality of pin and roller assemblies  80  extends around only one quarter of the drive wheel periphery. The space between adjacent pin and roller assemblies  80  is sufficient to enable one of the piston projections  60  to extend into the space. The number of pin and roller assemblies  80  also corresponds to the number of projections  60 . However, as stated earlier, different numbers of projections  60  and pin and roller assemblies  80  could be used. With the drive wheel  74  secured on the hydraulic motor shaft  68 , the drive wheel  74  is positioned adjacent the housing slot  36  and the line of projections  60  on the piston  52 . 
         [0037]    Operation of the apparatus  10  is represented in  FIGS. 11A-11D . To operate the apparatus  10 , the hydraulic motor hoses  70 ,  72  are connected to the appropriate fittings on the vehicle with which the apparatus is to be used. This connects the hydraulic motor  66  in the auxiliary hydraulic circuit of the vehicle. The auxiliary hydraulic circuit of the vehicle is then activated, causing the hydraulic fluid to cycle through the hydraulic motor  66 . This results in the hydraulic motor  66  rotating the shaft  68 , which in turn rotates the drive wheel  74 . As viewed in  FIGS. 11A-11D , the rotation of the drivel wheel  74  is counter clockwise. With the piston  52  being pressed against the strike plate  50  by the spring  62 , the rotation of the drive wheel  74  causes the plurality of pin and roller assemblies  80  to move over the plurality of projections  60  on the piston and not engage with the plurality of projections. This is represented in  FIG. 11A . 
         [0038]    The apparatus  10  is then moved by the operator of the vehicle to the post to be driven by the apparatus. The vehicle lift arms position the apparatus  10  over the top end of the post  82  and then lower the apparatus onto the post  82  as represented in  FIG. 11B . The top end of the post  82  passes through the opening  44  in the housing bottom wall  42  and engages against the strike plate  50 . Further downward movement of the apparatus by the vehicle lift arms onto the top end of the post  82  causes the post to push the strike plate  50  upwardly through the housing interior bore  30 . This movement of the strike plate  50  pushes the piston  52  upwardly in the housing interior bore  30  and begins compression of the spring  62 . Movement of the strike plate  50  in the cylindrical foot  38  is limited between the annular bottom wall  42  and the annular rim  34 . This enables the apparatus  10  to utilize the weight of the vehicle to which it is attached to assist in driving the post  82 . After the operator has lowered the apparatus  10  onto the post  82 , continued lowering of the apparatus  10  onto the post  82  transfers the weight of the vehicle onto the top of the post  82 . This, depending on the vehicle weight, can result in considerable force being applied to the post  82  prior to activating the apparatus  10 . 
         [0039]    With the piston  52  being raised above the lower position of the piston in the interior bore  30 , the projections  60  on the piston are moved upwardly to a position where they can be engaged by the plurality of pin and roller assemblies  80  on the drive wheel  74 . This is represented in  FIG. 11B . The rotation of the drive wheel  74  causes the pin and roller assemblies  80  to come into engagement with the plurality of projections  60  on the piston  52 . Further rotation of the drive wheel  74  causes the plurality of pin and roller assemblies  80  to push upwardly on the plurality of projections  60  and move the piston upwardly through the housing interior bore  30  from the strike plate  50  toward the top end  26  of the housing as represented in  FIG. 11C . This movement of the piston  52  further compresses the spring  62 . Still further rotation of the drive wheel  74  causes the plurality of pin and roller assemblies  80  to disengage from the plurality of projections  60 , releasing the piston  52  from its operative connection with the drive wheel  74 . This is represented in  FIG. 11D . The disengagement of the plurality of pin and roller assemblies  80  from the piston projections  60  causes the weight of the piston  52  and the force of the spring  62  to move the piston  52  downwardly toward the strike plate  50 . Engagement of the piston circular head surface  56  with the strike plate  52  exerts a force of impact on the top end of the post  82 , driving the bottom end of the post into ground. The continued rotation of the drive wheel  74  sequentially raises and then releases the piston for downward movement and impact with the strike plate  50  and the top end of the post  82 . This cycle is repeated six times per second with the vehicle auxiliary hydraulic circuit cycling at fifteen gallons per minute. 
         [0040]    With the post  82  driving into the ground to its desired depth, the vehicle operator then lifts the lift arms of the vehicle and the apparatus  10  from the driven post. Lifting the apparatus  10  from the post  82  allows the strike plate  50  to lay on the housing bottom wall  42  and causes the piston to be moved to the lower position of the piston in the interior bore  30  of the housing. This in turn positions the piston projections  60  where the drive wheel pin and roller assemblies  80  will pass over the projections on rotation of the drive wheel  74 . The vehicle operator then operates the vehicle to move the apparatus  10  to the next post location. 
         [0041]    As various modifications could be made in the construction of the apparatus and its method of operation herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present disclosure should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.