Abstract:
An hydraulic attachment ( 10 ) adapted to be mounted to machinery or a vehicle such as a skid-steer loader ( 35 ) and having a telescopic mast assembly ( 11 ) including a first lower mast member ( 12 ) and at least one second upper mast member ( 13 ) telescopically engaged with the lower mast member ( 12 ) and at least one hydraulic actuator ( 15 ) for extending or retracting the upper mast member ( 13 ) relative to the lower mast member ( 12 ). Mounting means ( 34 ) are provided for mounting the mast assembly ( 11 ) to the loader ( 35 ) so as to be supported in use in a substantially upstanding attitude and the mast assembly ( 12 ) includes support means ( 22 ) at its upper end for supporting or carrying a tool such as an impact applying tool ( 23 ).

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to an attachment, in particular to an hydraulic attachment which is particularly suited for use with skid steer loaders including small mechanical loaders such as stand on min-skid steer loaders. The attachment of the invention however is suitable for attachment to any form or size of machinery or vehicles. In a particular aspect, the present invention relates to an attachment which serves as a post driver for use in driving posts such as fence posts or guard rail posts into the ground. 
       BACKGROUND ART 
       [0002]    Where it is desired to install posts into the ground such as fence posts or guard rails posts, the common procedure is to use a earth drilling device to form a hole in the ground and thereafter install a post in the hole which is backfilled or filled with concrete to hold the post firmly in position. Alternatively the hole can be made manually. In either situation, the procedure is relatively time consuming and tedious where a large number of posts are to be installed. Removal of posts from the ground can also prove difficult. 
         [0003]    Some of the large earth working machines such as backhoes can be provided with pile driving attachments which are mounted on an articulated arm at the rear of the machine. It is difficult to manipulate the pile driver close to the post to be driven into the ground in these machines and hold the pile driver attachment in position during the pile driving operation. 
         [0004]    Current skid-steer loaders including min-loaders have a limited range of attachments usually related to the form of bucket attached to the loader. It would be desirable to provide an attachment which is suitably for use with a range of different devices or tools or for use for a range of different purposes for example for the purpose of post driving, post pulling or post hole drilling. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention aims to provide an attachment and in particular an hydraulic attachment which is particularly suited to use with a skid-steer loader and which may be used for a number of different purposes. The hydraulic attachment of the invention however may be used with other machinery such as other forms of loaders such as front end loaders or with or in association with other forms of vehicle. Other objects and advantages of the invention will become apparent from the following description. 
         [0006]    The present invention thus provides in one aspect a hydraulic attachment adapted to be mounted to machinery or a vehicle such as earth working machinery, said attachment including a telescopic mast assembly, said mast assembly including a first lower mast member and at least one second upper mast member telescopically engaged with said lower mast member, at least one hydraulic actuator for extending or retracting said upper mast member relative to said lower mast member, mounting means for mounting said mast assembly to said machinery so as to be supported in use in a substantially upstanding attitude, and support means at the upper end of said mast assembly for supporting or carrying a tool. 
         [0007]    The tool may comprise a post driver tool, an earth drilling tool or a post or tree extraction tool. Suitably the support means is adapted to support the tool such that the tool depends from the support means. The post driver tool for example may comprise reciprocative driving means for applying a reciprocative impact force to a post to be driven into the ground. Preferably the driving means comprise fluid driven driving means suitably pneumatic driving means. Preferably the driving means comprises a pneumatically reciprocative member which carries a weighted anvil or driving head. 
         [0008]    The earth drilling tool may comprise an auger drivable by any suitable driving means for applying rotation to the auger. The driving means may comprise an hydraulic motor. The post or tree extraction tool may include means to grip a post or tree trunk such as hydraulically actuated jaws. Alternatively the post or tree extraction tool may simply comprise a chain which is wrapped around a post or tree and secured to the mast assembly. 
         [0009]    Preferably the tools are detachably engageable with the support means. Preferably the upper ends of the tools are detachably engageable with the support means. Preferably the support means at the upper end of the mast assembly comprises an outwardly extending arm for supporting or carrying a tool. Preferably the respective tools are detachably engaged with the arm such that respective tools may be interchanged. If necessary the arm may be braced to the mast assembly. The mast assembly may have a foot at its lower end which may be engaged with the ground to stabilize the mast assembly in use. The foot may be adjustable from the lower end of the mast assembly for example by being telescopically extendable from the mast assembly. Preferably the foot comprises a planar member adapted to seat on a ground surface. 
         [0010]    The mounting means is suitably provided on the side of the post assembly opposite the support means for the tool. The mounting means suitably includes a first part fixed to the mast assembly and a second part mountable to the machinery. The mounting means may include means for adjusting the upright attitude of the mast assembly in a transverse vertical plane. The first and second parts are preferably pivotally mounted to each other pivotal movement relative to each other about an axis extending substantially normal to the mast assembly which in use comprises a generally horizontal axis. The means for adjusting the upright attitude of the post assembly suitably comprises means for pivoting the second part relative to the first part. The means for pivoting the second part relative to the first part suitably comprises at least one actuator. The actuator suitably is provided between the second part and the mast assembly. The at least one actuator suitably comprises at least one hydraulic ram. Preferably the second part extends laterally of the post assembly. Preferably the second part extends laterally to opposite sides of the post assembly and a pair of hydraulic rams is provided, respective rams being located on opposite sides of the mast assembly and extending between the laterally extending portions of the second part and the mast assembly. 
         [0011]    Means are suitably provided for holding the second part against, or in substantial juxtaposition with, the first part. The holding means suitably comprises at least one connector. The at least one connector suitably extends through at least one slot, suitably an arcuate slot in the first part which can accommodate limited pivotal movement of the first part relative to the second part. Preferably a pair of connectors are provided on opposite sides of the mast assembly and extend from the second part and through respective slots in the first part. Alternatively the second part may include at least one slot and at least one connector may extend from the first part and through the at least one arcuate slot in the second part. The connector or connectors suitable comprise bolts. 
         [0012]    Preferably the second part includes coupling means for coupling to a complementary coupling means carried by the machinery. Preferably the coupling means carried by the second part and machinery comprise male-female coupling means. Preferably the coupling means comprises attachment means for releasably attaching the second part to the complementary coupling means carried by the machinery. 
         [0013]    Preferably the second member of the mast assembly is received telescopically within the first member of the mast assembly. Preferably the second mast member is received non-rotatably within the first mast member. Preferably the first and second mast members comprise hollow sections preferably of a rectangular or square cross section, the sections being such that the second mast member has an external configuration of dimensions slightly less than the internal dimensions of the first mast member so as to be receivable in the first mast member for sliding movement relative thereto. 
         [0014]    The mast assembly suitably also includes a third mast member telescopically received within the second mast member. Preferably the third mast member is received non-rotatably within the mast member. Preferably the third mast member comprises a hollow section preferably of a rectangular or square cross section with an external configuration of dimensions slightly less than the internal dimensions of the second mast member such that the third mast member is receivable in the second mast member for sliding movement relative thereto. 
         [0015]    Preferably the support means for the tool such as an arm is rigidly connected to the third mast member. Preferably the arm extends substantially at right angles to the third mast member. Preferably means are provided to extend and retract the third mast member relative to the second mast member. Such means preferably comprise an hydraulic ram between the third mast member and second mast member. Preferably the hydraulic ram is connected between a bracket secured to the second mast member and third mast member. The bracket suitably comprises an elongated bracket secured at one end to the second mast member and extending longitudinally of the mast members and externally of the main mast member towards the normally lower end of the second and main mast members. 
         [0016]    In a further aspect, the present invention comprises machinery or a vehicle having an attachment described above mounted thereto. The machinery suitably comprises hydraulically operated machinery such as earth working machinery. Preferably the earth working machinery comprises a skid-steer loader or front-end loader and the mounting means mounts the attachment to the loader. 
         [0017]    According to a further aspect, the present invention provides an impact applying attachment adapted to be mounted to machinery such as earth working or loading machinery, said attachment including a telescopic mast assembly, mounting means for releasably mounting said post assembly to said machinery so as to be arranged in a substantially upstanding attitude, and support means from the upper end of said post assembly and extending therefrom, said support means carrying impact applying means. 
         [0018]    Preferably the impact applying means depends from the support means. Suitably the impact applying means is provided on the side of the mast assembly opposite the mounting means. Preferably the impact applying means is associated with a weighted driving head or anvil. 
         [0019]    The mast assembly and mounting means may be substantially of the same configuration as those described above. 
         [0020]    Whilst the impact applying attachment is particularly designed for driving posts or piles into the ground, the attachment may also be used in other applications by replacing the anvil or driving head with another form of too). Thus the driving bead m may be replaced with a rock or concrete breaking head. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0021]    In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: 
           [0022]      FIG. 1  illustrates in side elevation a hydraulic attachment according to an embodiment of the invention supporting a post driver; 
           [0023]      FIG. 2  is an opposite side elevation of the post driver of  FIG. 1 ; 
           [0024]      FIG. 3  is a partly cut-away sectional view of the mast assembly along line A-A of  FIG. 1  (excluding the hydraulic extension rams); 
           [0025]      FIG. 4  illustrates the attachment fitted to a skid-steer loader for driving a post into the ground; 
           [0026]      FIG. 5  illustrates an auger assembly for mounting to the attachment; 
           [0027]      FIG. 6  illustrates a post gripper for mounting to the attachment; and 
           [0028]      FIG. 7  illustrates the manner in which a chain puller is used with the attachment for removing a post from the ground. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    Referring to the drawings and firstly to  FIGS. 1 to 3 , there is illustrated an attachment  10  typically for small size earth-working machinery according to an embodiment of the invention, the attachment  10  comprising an elongated telescopic mast assembly  11  comprising an outer elongated main hollow mast member  12  of square cross section, a second inner elongated hollow mast member  13  of complementary square cross section to and within the main mast member  12  and a third inner elongated hollow mast member  14  of complementary square cross section to and within the second inner hollow mast member  13 . The members  12 ,  13  and  14  may thus be extended telescopically relative to each other to extend the length of the mast assembly  11 . Slides  10 ′ (shown in dotted outline in  FIGS. 1 and 2 ) are provided within the upper ends of the main hollow member  12  and second inner hollow member  13  and at the lower end and on the outside of the second inner hollow member  13  and third inner hollow member  14 . The slides  10 ′ are provided on each of the faces of the respective members so as to occupy the space between the respective members  12  and  13  and  13  and  14  to facilitate smooth movement of the members  12 ,  13  and  14  during telescopic extension and retraction of the post assembly  11 . 
         [0030]    A first hydraulic ram  15  which extends longitudinally of the mast assembly  11  is mounted at opposite ends via mounting brackets  16  and  17  to a lower part of the main hollow member  12  and an upper part of the second member  13  respectively on one side of the mast assembly  11 . A second hydraulic ram  18  which also extends longitudinally of the mast assembly  11  is provided on the opposite side of the mast assembly  11  to the ram  15  and is mounted at its opposite ends  19  and  20  respectively to a bracket at an upper part of the third member  14  and a bracket  21  which is attached at  21  such as by welding to an upper part of the second member  13 , the bracket  21  being of a generally elongated U-shape configuration and extending from its attachment point  21 ′ downwardly along and on the outside of the mast assembly  11  towards a lower end of the main member  12  so that the lower end of the bracket  21  to which the lower end of the ram  18  is attached is free. 
         [0031]    Extension of the first ram  15  will extend the second and third members  13  and  14  together and simultaneously from the main member  12  whist extension of the second ram  18  will extend the third member  14  from the second member  13 . Similarly retraction of the ram  18  will retract the third member  14  into the second member  13  and retraction of the ram  15  will retract the third member  14  and second member simultaneously into the main member  12 . 
         [0032]    Extending substantially at right angles from and rigidly fixed to the third member  14  is a tool support in the form of a boom arm  22 . The boom arm  22  carries in this case an impact hammer  23  which is mounted at its upper end to the arm  22  to depend therefrom so as to be substantially parallel to the mast assembly  11 . The hammer  23  comprises a pneumatically driven impact hammer provided with a weighted impact head or anvil  24 . Pressurized air applied to the impact hammer  23  will cause reciprocation of the driving mechanism of the impact head  24  in a substantially vertical direction. Typically the impact hammer  23  comprises a rock breaker with the driving pin thereof being connected to the impact head  24 . 
         [0033]    The attachment  10  additionally includes a mounting assembly  25  on the side of the mast assembly  11  opposite the arm  22  and impact hammer  23  for mounting the attachment  10  to a suitable prime mover. The mounting assembly  25  comprises a first plate  26  which is fixed rigidly to the main member  12  and extends laterally on opposite sides thereof and a second similar plate  27  which is pivotally mounted to the first plate  26  by a pivot pin  28  (shown in dotted outline) extending through aligned openings in the plates  26  and  27  whereby the plate  27  is mounted for rotation relative to the plate  26  about an axis extending normal to the longitudinal axis of the mast assembly  11 . The second plate  27  is retained to the first plate  26  by a pair of bolts  29  on opposite sides of the post assembly  11 , the bolts  29  passing through arcuate slots  30  in the first plate  26  which allow for limited pivotal movement of the second plate  27  and bolts  29  relative to the first plate  26 . The bolts  29  at the same time maintain the plates  26  and  27  in substantial face-to-face contact. 
         [0034]    A pair of hydraulic rams  31  are provided on opposite sides of the mast assembly  10  respectively and extend between lugs  32  on the opposite outer sides of the second plate  27  and lugs  33  on opposite side of the main member  12 . Corresponding retraction and extension of the rams  31  on opposite sides of the mast assembly  11  will thus cause pivotal movement of the first plate  26  and thus mast assembly  11  relative to the second plate  27  in a transverse vertical plane as indicated by the arrows in  FIG. 3 . 
         [0035]    The second plate  27  also carries a coupling  34  to enable the attachment  10  to be mounted to a prime mover such as a stand-on mini skid-steer loader  35  (see  FIG. 4 ). Thus a loader  35  provided with a complementary coupling  36  to the coupling  34  can engage and support the attachment  10 , the coupling  36  being provided at the end of link arms  37  of the loader  35  which can be hydraulically elevated or lowered. The coupling  36  is provided with spring-loaded pins  38  to enable positive connection between the couplings  34  and  36  when arranged in a mating complementary relationship with each other, the pins  38  being adapted to locate in corresponding holes  38 ′ in the coupling  34 . 
         [0036]    When the attachment  10  is mounted to a loader  35  as in  FIG. 4  and the attachment  10  is to be used to drive a fence post  39  or the like into the ground, the impact hammer  23  is mounted to the arm  22  and the loader  35  is used to position the mast assembly  11  adjacent to the post  39  and the ram and/or rams  15  and/or  18  are used to extend the mast assembly  11  and elevate the impact hammer  23  above the post  39 . The loader  35  can be manipulated towards and away from the post  39  so that the impact head  24  is substantially vertically above the post  39 . The hydraulic rams  31  are actuated if required to pivot the mast assembly  11  about a substantially horizontal axis as indicated by the arrows in  FIG. 3  until it is in a substantially vertical position and hydraulic rams which are on the loader  35  and which control the arms  37  can also be adjusted to ensure that the mast assembly  10  is substantially upright. Pressurized air can then be applied to the impact hammer  23  so that the impact head  24  will reciprocate and apply an impact force to the upper end of the post  39  to drive it into the ground. As the post  39  is forced into the ground, the ram and/or rams  15  and/or  18  may be retracted to lower the boom arm  22  for example from the dotted outline position of  FIG. 4  to maintain the impact hammer  23  in a position such that the impact head  24  will continued to apply an impact to the post  39 . This procedure is repeated until die post  39  is driven to the required depth into the ground. 
         [0037]    Whilst in the embodiment shown in  FIG. 4 , the mast assembly  10  is raised above the ground, the loader  35  can lower the mast assembly  10  onto the ground so that it is supported during the post driving operation. To support the mast assembly  10 , the lower end of the mast member  12  may be provided with a foot  40  shown in dotted outline in  FIG. 4  which may comprise a flat plate for seating flat on the ground. The foot  40  may be mounted for telescopic extension from the mast assembly  10 . 
         [0038]    All hydraulic fluid for supplying the rams  15 ,  18  and  31  is supplied from the hydraulic supply of the loader  35  and under the control of hydraulic valves on the loader  35  controllable by the operator of the loader  35 . An auxiliary hydraulic supply however may be used to supply fluid to the rams. 
         [0039]    The impact hammer  23  most suitably is detachable mounted to the arm  22  through a detachable coupling  41  which comprises complementary coupling parts on the arm  22  and hammer  23 . Thus the hammer  23  may be removed and replaced with other forms of tool for example an hydraulically operated auger assembly  42  as shown in  FIG. 5 . The hydraulic attachment  10  may also carry a drilling device used for deep hole drilling where a series of drill rods may be interconnected one above the other. Thus the hydraulic attachment  10  carrying such a drilling device may be initially extended for attachment of the drilling rods to the drilling motor and then lowered to urge the drill rods into the ground. At the retracted position of the hydraulic attachment  10 , the drill rods may be disconnected from the drilling motor and the attachment  10  then extended to enable attachment of a further drill rods between the drilling motor and drill rod in the ground and the procedure repeated until the required depth is achieved. 
         [0040]    Where the attachment  10  is to be used for extracting a member from the ground such as the post  39 , a post gripper  43  as shown in  FIG. 6  may be attached to the arm  22  and lowered such that the jaws  44  of the gripper  43  can locate about the post  39  for gripping the post  39  (shown in dotted outline). For post extraction, to support the hydraulic attachment  10 , the member  12  is lowered by the loader  35  such that the foot  40  seats on the surface of the ground. Alternatively, the foot  40  may be extended from the lower end of the member  12  to engage the ground. The post gripper  43  may then be actuated such that the jaws  44  grip the post  39  after which the rams  18  and/or  15  may be extended to elevate the mast assembly  11  and arm  22  and extract the post  39 . 
         [0041]    In a simplified arrangement, the attachment  10  may include one or more attachment points  45  to which a chain may be connected. Preferably and as illustrated in  FIG. 7 , one attachment point  45  may be provided on top of the mast assembly and another attachment point  45 ′ at or adjacent the outer end of the arm  22 . For removal of a post  39  or other member in the ground such as a tree or tree stump, the chain  46  is wrapped around the post  39  or tree and secured to one or both attachment points  45  (an/or  45 ′). The attachment  10  may then again be elevated by means of the rams  15  and/or  18  such as to the position shown in dotted outline in  FIG. 7  to lift the arm  22  and the chain  46  and thus lift the post  39  (or other member) from the ground. 
         [0042]    Whilst the attachment  10  is shown and described in association with a mini skid-steer loader, it may be used with other forms of machinery such as earth working machinery or attached to a vehicle. Furthermore whilst the embodiment of  FIG. 4  is described as a post driver, a substitute head may be used in place of the impact applying head  24  for other applications such as for jack hammer or rock breaking operations. Whilst the impact hammer  23  suitably comprises a pneumatically operated hammer, it may be any other form of impact applying tool such as a hydraulically operated hammer or tool. 
         [0043]    It will also be appreciated that may different forms of tool may be coupled to the arm  22  through the complementary coupling  41 . The coupling  41  may be of many different configurations which will permit secure but releasable attachment of a tool to the arm  22 . 
         [0044]    Where the hydraulic attachment  10  is to be used for post removal applications, it may not be necessary to include the mounting assembly  25  to provide for vertical adjustment of the attachment  10 . 
         [0045]    It also may be desirable to brace the arm  22  in some applications and for this purpose a bracing member  47  shown in dotted outline in  FIG. 1  may be provided between and connected to the arm  22  and member  14 . To accommodate movement of the member  14  relative to the member  12  and/or  13 , the members  12  and  13  are provided with longitudinally extending aligned slots  48  and  49  through which the bracing member  47  passes (see  FIG. 3 ) for attachment to the member  14 . 
         [0046]    The term “comprising” or “comprises” as used throughout the specification are taken to specify the presence of the stated features, integers and components referred to but not preclude the presence or addition of one or more other feature/s, integer/s, component/s or group thereof. 
         [0047]    The above has been given by way of illustrative embodiment of the invention. It will be appreciated however that all variations and modifications to the invention as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined in the appended claims.