Patent Publication Number: US-7219454-B2

Title: Attachment system

Description:
FIELD OF THE INVENTION 
   The present invention relates to an attachment system, particularly intended for the attachment of ground engaging tools to the lip plate of mechanical digging devices. 
   Many mining and earthmoving operation require the use of mechanical digging devices, such as front-end loaders. Such mechanical digging devices commonly feature buckets which can be manipulated by a user to dig into earth or rocks to be shifted. These buckets include a lip plate across the bucket floor. On this lip are mounted a series of ground engaging tools having a tooth-like appearance. These tools, in use, penetrate into the material being dug, and provide a leading edge for the bucket to follow. 
   The ground engaging tools are highly susceptible to wear due to the high level of friction generated by their use. Accordingly, it is often desirable to be able to remove a worn ground engaging tool and substitute a new tool. 
   A common method of attachment for ground engaging tools is that of welding. In practice, however, a welded ground engaging tool can be difficult to replace without substantial dismantling of the bucket. 
   Mechanical methods of attaching ground engaging tools through the use of restraining bolts and pins have been proposed. These methods are often difficult to use in practice, as the forces generated against a ground engaging tool can cause deformation of the bolt or pin, thus making subsequent disengagement difficult. 
   The present invention attempts to overcome at least in part some of the aforementioned disadvantages of previous attachment system for ground engaging tools. 
   SUMMARY OF THE PRESENT INVENTION 
   In accordance with one aspect of the present invention there is provided an attachment system for connecting a first member to a second member, characterised in that the first member has a lug connected thereto, and the second member has an aperture arranged, in use, about the lug and wherein a clamping member is disposed between the lug and the second member such that the supply of pressure to the clamping member acts to restrain disengagement of the second member from the lug. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a ground engaging tool arranged to be attached to a lip plate (a portion of which is shown) in accordance with the present invention; 
       FIG. 2  is perspective view of the underside of the ground engaging tool of  FIG. 1 ; 
       FIG. 3  is a perspective view of the ground engaging tool and lip plate portion of  FIG. 1 , shown during attachment, together with a clamping member in accordance with a first aspect of the present invention; 
       FIG. 4  is a cross sectional view of a portion of the ground engaging tool and lip plate showing the clamping member of  FIG. 3 , and showing a stabilizing member; 
       FIGS. 5 to 9  are sequential cross sectional views of the arrangement of  FIG. 4  shown during the attachment process; 
       FIG. 10  is a perspective view of the ground engaging tool and lip plate portion of  FIG. 1 , shown during attachment, together with a clamping member in accordance with a second aspect of the present invention; 
       FIG. 11  is a cross section view of a portion of the ground engaging tool and lip plate showing the clamping member of  FIG. 10 , and showing a stabilizing member; and 
       FIGS. 12 and 15  are sequential cross sectional views of the arrangement of  FIG. 11  shown during the attachment process. 
   

   DESCRIPTION OF THE INVENTION 
   Referring to the Figures, there is shown a ground engaging tool  10  arranged to be attached to a portion of a lip plate  12 . The lip plate  12  is substantially rectangular in cross section, and extends around the rim of a bucket (not shown) of a mechanical digging device. The lip plate  12  includes an upper face  14 , a lower face  16  and an end face  18 . A tapered surface  20  extends from the end face  18  of the lip plate  12  to the upper face  14 . 
   The lip plate  12  includes a lug  22  affixed by suitable means (for instance welding) to the upper face  14 . The lug  22  includes an elliptical prism portion  24  oriented towards the end face  18  of the lip plate  12 , a top face  26  substantially parallel to the upper face  14  of the lip plate  12 , a tapered surface  28  extending from the edge of the top face  26  to the edge of the elliptical prism portion  24  and a substantially flat rear face  30  oriented substantially perpendicularly to the upper face  14 . 
   The ground engaging tool  10  comprises a leading edge  32 , a first base portion  34  extending substantially perpendicularly of the leading edge  32 , a front portion  36  extending away from the leading edge at a shallow angle, a second base portion  38  extending away from the first base portion  34  at a shallow angle, a transverse recess  40  disposed oppositely the leading edge  32  and an attachment portion  42 . The front portion  36 , leading edge  32  and the first base portion  34  co-operate to form a substantially V shaped working position in order to penetrate, in use, the material being dug. The transverse recess  40  is complementary in shape to the lip plate  12 , and allows the ground engaging tool  10  to be located on the perimeter of the lip plate  12  adjacent the end face  18 . The second base portion  38  tapers from the first base portion  34  in a direction away from the leading edge  32 , and ends, in use, adjacent the lip-plate  12 . The leading edge  32 , first and second base portions  34  and  38  and the front portion  36  define a working portion of the ground engaging tool  10 . 
   The attachment portion  42  extends from the front portion  36  adjacent the recess  40  in a direction away from the leading edge  32 . It locates, in use, along the upper face  14  of the lip plate  12 , and co-operates with the lug  22 . 
   The attachment portion  42  has a substantially flat lower surface  44 , a substantially flat upper surface  46  and a rear surface  48 . The attachment portion  42  includes an engaging recess  50  extending inwardly of the rear surface  48  through a rear aperture  52  in the rear surface  48 , and upwardly of the lower surface  44  through a lower aperture  45 . The engaging recess has a first portion  54  remote from the rear aperture  52 , and a second portion  56  adjacent the rear aperture  52 . The first portion  54  is complementary in shape to the lug  22 , whereas the second portion  56  is of larger transverse dimension than the first portion  54 . This allows, in use, the second portion  56  to be placed about the lug  22 . This in turn allows the attachment portion  42  to be slid over the lug  22  in a longitudinal direction, and to locate in a position whereby the lug  22  is within the first portion  54  of the engaging recess  50 . In this position relative movement of the attachment portion  42  and the lip plate  12  in a transverse direction is restricted. 
   The attachment portion  42  further includes an aperture  58  within the upper surface  46 . The aperture  58  communicates with the second portion  56  of the engaging recess  50 . When the ground engaging tool is located such that the front of the lip plate  12  is engaged in the transverse recess  40  and the lug  22  is within the first portion  54  of the engaging recess  50 , the aperture  58  is situated adjacent the rear face  30  of the lug  22 . 
   The attachment system further includes a clamping member  60 . The clamping member ( 60 ) will now be described with respect to a first embodiment of the invention as shown in  FIGS. 3 to 9 . 
   The clamping member  60  is of complementary cross section shape to the second portion  56  of the engaging recess  50  and has a first side  64  which is arranged to locate adjacent the lug  22  and a second side  66  opposite the first side  64 . The second side  66  is arranged to locate adjacent the rear aperture  52 . The clamping member  60  further includes side surfaces  67  and a top surface  68 . 
   The clamping member  60  includes a recessed edge  70  extending between the first side  64  and the top surface  68 . The recessed edge  70  is arranged to be complementary in shape to a lip  72  extending from the upper portion  46  of the attachment portion  42  partially above the second portion  56  of the engaging recess  50 . 
   The clamping member  60  includes a substantially cylindrical lug engaging member  62 . The lug engaging member  62  is arranged to slide from a first position where it is substantially contained within a chamber  80  within the clamping member  60  to a second position where the lug engaging member  62  extends from the first side  64  of the clamping member  60 . 
   The chamber  80  extends within the clamping member  60  from the first side  64  to a rear wall  82 . The chamber  80  is substantially cylindrical in shape, and is complementary in shape to the lug engaging member  62 . 
   A fluid path  84  extends from the rear wall  82  of the chamber  80  to a fluid junction  86  located within the clamping member  60 . 
   A substantially cylindrical fluid outlet  88  extends between the fluid junction  86  and the second side  66  of the clamping member  60 . 
   A substantially cylindrical fluid inlet  90  extends between the fluid junction  86  and the top surface  68  of the clamping member  60 . 
   A substantially cylindrical, hollow first fluid conduit  92 , complementary in shape to the fluid inlet  90 , is located within the fluid inlet  90  adjacent to the fluid junction  86 . The hollow interior of the first fluid conduit  92  is fluidly connected to the fluid junction  86  through a one way valve  87 . 
   A substantially cylindrical, hollow second fluid conduit  94 , complementary in shape to the fluid inlet  90 , is located within the fluid inlet  90  and extends between the first fluid conduit  92  and the top surface  68 . Adjacent the top surface  68  the second fluid conduit  94  has a grease nipple  96 . The grease nipple  96  is fluidly connected with the hollow interior of the second fluid conduit  94 , which is in turn fluidly connected with the hollow interior of the first fluid conduit  92  and thus the fluid junction  86 . 
   The fluid inlet  90  may be internally threaded, and the first and second fluid conduits  92 ,  94  externally threaded in complementary fashion. 
   The attachment system further includes a stabilizing member  98 . The stabilizing member  98  is in the form of a prism, having front and rear faces  100 ,  102  which are substantially the same shape as the cross sectional shape of the second portion  56  of the engaging recess  50 . 
   The stabilizing member  98  has a similar width to the lip  72  of the attachment portion  42 . 
   The stabilizing member  98  has a substantially cylindrical aperture  104  which is arranged to locate, in use, adjacent the fluid outlet  88  of the clamping member  60  so as to form a single cylindrical fluid pathway. 
   A substantially cylindrical plug  106  is arranged, in use, to locate within the fluid pathway formed by the fluid outlet  88  and the aperture  104  to prevent the flow of fluid from the fluid junction  86  through the fluid outlet  88 . The plug  106  may be externally threaded and the fluid outlet  88  internally threaded in complementary fashion. The plug  106  further acts to hold the stabilizing member  98  relative to the clamping member  60  during use. 
   The use of the clamping member  60  according to the first embodiment will now be described. 
   The attachment portion  42  is positioned over the lip plate  12  with the lug  22  located within the first portion  54  of the engaging recess  50 . 
   The clamping member  60  is then introduced through the aperture  58 . When the clamping member is within the engaging recess  50  it is slid forward relative to the attachment portion  42  such that the recessed edge  70  is engaged by the lip  72 . 
   The clamping member  60  may be provided with channels  69  provided in the side surfaces  67 . The channels  69  are arranged to cooperate with side lugs  71  within the second portion  56  of the engaging recess  50  in order to define a track along which the clamping member is slid within the engaging recess  50 . 
   The stabilizing member  98  is then introduced between the second side  66  of the clamping member  60  and the rear aperture  52 . 
   The clamping member is activated as follows. The plug  106  is inserted into the cavity created by the fluid outlet  88  and the aperture  104 . A fluid  107  is then introduced under pressure through the grease nipple  96 . The fluid  107  is passed through the first and second fluid conduits  92 ,  94  and the one way valve  87  to the fluid junction  86 , and thence through the fluid path to the chamber  80 . The effect of the pressure in the chamber  80  is to force the lug engaging member  62  form its first portion to its second position, whereby it engages the rear face  30  of the lug  22 . In this way a compressive force is applied between the lug  22  and the attachment portion  42 , thus locking the ground engaging tool  10  in position relative to the lip plate  12 . 
   Once the ground engaging tool  10  is thus locked into position, the second fluid conduit  94  along with grease nipple  96  can be removed and replaced with a second plug  108  arranged to fit within the fluid inlet  90 . In this way the top surface  46  of the attachment portion  42  is substantially flat. The second plug  108  may be externally threaded if the fluid inlet  90  is internally threaded. 
   When it is desired to remove the ground engaging tool  10  from the lip portion  12 , the plug  106  is removed from the fluid outlet  88 . Pressurized fluid ( 107 ) can then flow from the chamber  80  through the fluid junction  86  and out through the fluid outlet  88  and aperture  104 . The attachment portion  42  can then be readily removed from the lip portion  12  in the reverse of the above process, potentially allowing some members to be reused. 
   The clamping member ( 60 ) will now be described with respect to a second embodiment of the invention as shown in  FIGS. 10 to 15 , with like numerals denoting like parts. 
   The clamping member  60  is of complementary cross sectional shape to the second portion  56  of the engaging recess  50  and has a first side  64  which is arranged to locate adjacent the lug  22  and a second side  66  opposite the first side  64 . The second side  66  is arranged to located adjacent the rear aperture  52 . The clamping member  60  further includes side surfaces  67  and a top surface  68 . 
   The clamping member  60  includes a recessed edge  70  extending between the first side  64  and the top surface  68 . The recessed edge  70  is arranged to be complementary in shape to a lip  72  extending from the upper portion  46  of the attachment member  42  partially above the second potion  56  of the engaging recess  50 . 
   The clamping member  60  includes a substantially cylindrical lug engaging member  62 . The lug engaging member  62  is arranged to slide from a first position where it is fully contained within a chamber  80  within the clamping member  60  to a second position where the lug engaging member  62  extends from the first side  64  of the clamping member  60 . 
   The chamber  80  extends within the clamping member  60  from the first side  64  to a rear wall  82 . The chamber  80  is substantially cylindrical in shape, and is complementary in shape to the lug engaging member  62 . 
   A substantially cylindrical slot  110  extends from the chamber  80  adjacent a rear end of the lug engaging member  62  to the second side  66  of the clamping member  60 . The slot  110  is internally threaded. 
   The attachment system further includes a stabilizing member  98 . The stabilizing member  98  is in the form of a prism, having front and rear faces  100 ,  102  which are substantially the same shape as the cross sectional shape of the second portion  56  of the engaging recess  50 . 
   The stabilizing member  98  has a similar width to the lip  72  of the attachment portion  42 . 
   The stabilizing member  98  has a substantially cylindrical aperture  112  which is arranged to locate, in use, adjacent the slot  110  of the clamping member  60  so as to form a single cylindrical passageway. 
   A forcing member in the form of a substantially cylindrical bolt  114  is arranged, in use, to locate within the passageway formed by the slot  110  and the aperture  112 . The bolt is externally threaded, and is arranged to engage with the internally threaded slot  110 . The bolt acts to hold the stabilizing member  98  relative to the clamping member  60  during use. 
   The use of the clamping member  60  according to the second embodiment will now be described. 
   The attachment portion  42  is positioned over the lip plate  12  with the lug  22  located within the first portion  54  of the engaging recess  50 . 
   The clamping member  60  is then introduced through the aperture  58 . When the clamping member is within the engaging recess  50  it is slid forward relative to the attachment portion  42  such that the recessed edge  70  is engaged by the lip  72 . The clamping member  60  may be provided with channels  69  provided in the side surfaces  67 . The channels  69  are arranged to cooperate with side lugs  71  within the second portion  56  of the engaging recess  50  in order to define a track along which the clamping member is slid within the engaging recess  50 . 
   The stabilizing member  98  is then introduced between the second side  66  of the clamping member  60  and the rear aperture  52 . 
   The clamping member is activated as follows. The bolt  114  is introduced into the passage created by the slot  110  and the aperture  112 , and is threadedly engaged with the slot  110 . When the bolt  114  is fully within this passage, the end of the bolt  114  is adjacent the lug engaging member  62 . The application of a turning force to the bolt so as to promote the further advance of the bolt into the chamber  80  provides a pressing force on the lug engaging member  62 . 
   The effect of the pressure in the chamber  80  is to force the lug engaging member  62  from its first position to its second position, whereby it engages the rear face  30  of the lug  22 . In this way a compressive force is applied between the lug  22  and the attachment portion  42 , thus locking the ground engaging tool  10  in position relative to the lip plate  12 . 
   When it is desired to remove the ground engaging tool  10  from the lip portion  12 , the bolt  114  is unscrewed from the slot  110 , thus releasing pressure from the lug engaging portion  62 . The attachment portion  42  can then be readily removed from the lip portion  12  in the reverse of the above process, potentially allowing some members to be reused. 
   Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.