Excavating – Combined or convertible – With scraper
Reexamination Certificate
2002-10-28
2004-10-05
Pezzuto, Robert E. (Department: 3671)
Excavating
Combined or convertible
With scraper
C037S450000, C037S454000, C037S446000
Reexamination Certificate
active
06799388
ABSTRACT:
The application claims priority under 35 U.S.C. §§119 and/or Patent Application Serial No. PR8512 filed in Australia on Oct. 26, 2001, the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a surface working device, such as for planing and grading roads, and to an attachable protector for the same.
Various road maintenance systems exist for working road surfaces. Such working may for example take the form of grading and planing a road, e.g., in order to provide a dirt road or the like with a smooth driving surface. It could also take the form of for example ice and snow scraping for keeping roads open in winter conditions, as well as asphalt planing and gravel maintenance.
As shown in
FIG. 1
, such systems typically include a planing blade
1
which breaks up and smooths the surface of a road. The blade
1
is mounted beneath a vehicle between the vehicle's front and rear wheels F and R.
The planing blade
1
is generally angled to the direction of movement D of the vehicle, this angle (denoted &agr; in
FIG. 1
) being changed dependent on, e.g., the hardness of the surface being worked.
One such known system is the Sandvik System 2000™ provided by Sandvik AB of Sandviken, Sweden.
As shown in
FIG. 2
, this system utilizes a cutter board
2
that is attached to the planing blade
1
and has a plurality of rotating picks
3
mounted within it. The picks
3
break up the road surface as the grading vehicle advances.
Details of this system can be found in U.S. Pat. No. 4,784,517, the contents of which are incorporated herein by reference.
As the planing blade
1
is angled with respect to the vehicle's direction of motion D, the leading edge
4
of the cutter board
2
(corresponding to the leading edge
5
of the planing blade
1
) is subject to wear.
In order to counter this, an end protector
6
, shown in
FIG. 11
, has been devised for the cutter board
2
.
This end protector
6
is mounted on the cutter board
2
by bolts
7
(only one shown) which extend through bolt holes
8
of the protector
6
and similar bolt holes
9
in the cutter board
2
and in the blade
1
.
The end protector
6
protects the leading edge
4
of the cutter board
2
against wear, and can extend the life of the cutter board
2
.
The inventors of the present invention have found, however, that problems can occur when the blade
1
is used to grade or plane hard road surfaces, such as are often found on dirt roads and country tracks.
These problems can include a riding up of the protector
6
over the cutter board
2
, so as to expose the leading edge
4
of the cutter board
2
to wear. Furthermore, the bolts
7
holding the protector
6
in place can sometimes loosen and shear off under the loading actions experienced during use.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention aims to provide an alternative end protector that is designed to address such problems.
Viewed from one aspect, the present invention provides an end protector for a working element of a surface working device, the working element having a body portion with a plurality of holes therein for receiving pick elements, wherein the end protector is configured for attachment to the working element by the use of one or more of the pick holes.
From this aspect, therefore, the present invention can be seen to reside in the removal of one or more of the end picks from the working element, e.g., cutter board, so as to allow the end protector to be mounted to the working element through the unused pick hole or holes.
This may be achieved, for example, by having a fastening member, such as a bolt, extend into and/or through the or each empty pick hole and engage the end protector.
The use of one or more of the pick holes to mount the end protector in place provides a secure attachment that resists riding up of the end protector. Furthermore, the orientation of the bolt or other fastener within the pick hole helps to reduce the likelihood of bolt shear or the like.
An end protector attached in accordance with the present invention may provide good protection for the working element when for example it is used in the working of hard surfaces, such as compacted dirt tracks and the like, and may also be used, e.g., in mining board systems for, e.g., open cut mines, quarries and hard rock mines. It may also however be used with working elements in general across the range of working applications, such as ice and snow clearing and the like.
In many situations, the use of one pick hole to mount the end protector may be all that is required. For extra stability, however, one or more further pick holes could be used to mount the end protector, so that for example the two pick holes that are closest to the leading edge of the working element could be used.
The attachment of the end protector to the working element may take any suitable form, as may the shape and construction of the end protector.
In one preferred embodiment, the end protector is configured to slide onto the end of the cutter board, and includes at least one hole or slot that extends over a top and/or bottom opening of one of the end pick holes. A fastening element may then extend through the hole/slot and into the pick hole to hold the end protector in place.
For example, a bolt or other fastener may extend through a hole or slot in an upper face of the end protector, downwardly through the pick hole and into a recess in a lower portion of the end protector. In order to secure the fastener, the recess may for example be tapped or a suitable thread could be provided in the hole or slot in the end protector upper face.
Alternatively, the bolt or fastener could extend in the opposite direction, and as a further alternative, the recess could be replaced by a hole allowing the fastener to extend completely through the end protector and to be fastened by further means, such as a nut or the like.
As well as bolts, other fastening means could be used, for example screw, clip and/or bayonet type constructions could be used, and the bolt may be replaced by some other shaft member or stud element. Other fastening systems could include similar systems to those used to hold the picks in place in the holes, e.g., a split spring sleeve mounted on a bolt or shaft/stud element of the end protector which resiliently engages the insides of the pick holes.
In one preferred embodiment, the fastening element has a shank portion of narrower dimensions, e.g., diameter, than a head portion, e.g. so that the fastening element is of a stepped configuration. The stepped portion may provide a sharp transition or a more gradual curved transition.
In this embodiment, the transition, e.g., stepped, section between the head portion and the shank portion, e.g., a bottom surface of the head portion, may bear against the body portion of the working element so as to provide a force between the end protector and the working element in order to hold or assist in holding the end protector in place. This fastening element may screw into the end protector, and may include a threaded portion at the head portion and/or at the end of the shank portion for engagement with a threaded hole or recess in the protector. When the fastening is provided at the head portion, the shank portion need not be sized to extend completely through a pick hole, and may instead merely extend part way into the pick hole.
Although preferably of one piece construction and slidable onto the end of the working element, the end protector may be of, e.g., two-part construction, in which case the parts could be connected together on mounting the protector to the working element. They may for example be clamped or bolted together or otherwise fastened. In such situations, the actual fastening element of the end protector need not necessarily extend through the vacated pick hole or holes, rather a stud or the like could extend into or through the pick hole to hold the end protector in place, whilst fastening, e.g., the clamping together of the two portions of the
McLean Michael Andrew
Truebody Mark James
Weaver Steven
Beach Thomas A
Burns Doane Swecker & Mathis L.L.P.
Pezzuto Robert E.
Sandvik AB
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