Note: Descriptions are shown in the official language in which they were submitted.
2161505
SAFETY LOCK PIN FOR EXCAVATION POINT AND ADAPTOR
Field of the Invention
This invention relates to the field of excavating teeth
and in particular to assemblies for attaching a ground
engaging tooth to an adaptor on an excavating tool.
Background of the Invention
At approximately the turn of the 20th century, excavating
tools employed excavating teeth with replaceable ground
engaging tips known as points. The points were connected to
an adaptor attached to the shovel dipper, drag-line bucket or
similar tool. An example is disclosed in U.S. Patent No.
564,664. As the two part assembly became established
practice, a number of methods evolved for joining the point
to the adaptor. Depending on the mine conditions, a given
adaptor would be successively re-equipped with 5 to 30 teeth
or points to maintain a sharp penetrating edge during
excavation. The ease of replacement of the point became
important because it minimized the amount of wasted throw-away
metal and also m; n;m; zed the down time of the tool.
The assemblies used to attach a point to the adaptor
consisted mainly of two designs, the wedge design and the pin
design. In the wedge design, the point is joined to the
adaptor by wedges hammered in place. One disadvantage of this
method is the wedges would often become dislodged during use
of the excavating tool. This design posed serious safety
hazards to workers. To prevent this danger, the wedges were
often tack-welded in place. However, removal of the wedges
was then difficult and time consuming. Another disadvantage
of this method is that the removal of the wedge requires the
drag-line bucket to be turned up on its front end in order to
gain access to the wedge.
U.S. Patent No. 3,256,622 describes a wedge pin assembly
used to fasten a point to the adaptor. The wedge pin is
-- 1 --
S
received into an open-ended slot. The wedge pin is removed
- by being hammered through the slot with a specially designed
hammer having a head size smaller than the slot size. The
wedge pin is designed to cause interference in the slot but
still be removable. One disadvantage of this arrangement is
the tendency of the wedge to shatter or break during removal
causing pieces to jam as well as dangering workers.
U.S. Patent No. 4,326,348 discloses a pin design
incorporating a pin and lock washer. The lock washer ensures
the pin does not dislodge during service. The adaptor and the
point have openings which accommodate the pin and the lock
washer. The lock washer is placed overtop the adaptor pin
hole and the point is placed in position on the adaptor with
the pin holes in line. Once the holes in the adaptor and
point line up, the pins are hammered into place. The pins are
removed by further hammer driving. A common criticism with
this device is that it is difficult to remove the pins because
of the impact fines and the tight tolerances between the
adaptor and the point.
Another pin assembly is disclosed in Canadian Patent
Application No. 2,121,993. This patent discloses a threaded
pin and insert assembly to secure a point onto the adaptor.
A threaded insert is placed into the adaptor pin opening. The
point is then placed over the adaptor. A lock washer is
concentrically placed over the pin opening on the point. The
pin is screwed into the insert. Disadvantages of this
assembly include the loosening of the pin from the insert
while the point-adaptor assembly is in use and the cumbersome
and relatively complex design. A work accident may occur
during the assembly and disassembly of the pieces.
Furthermore, the point replacement time is longer than with
more conventional tèeth.
Generally locking devices are designed to minimize the
down time of the equipment and increase the life of the point
and adaptor. With the increase in awareness of worker safety,
-- 2
21 ~ 1 505
another important requirement of the point-adaptor assembly
is a safe and easy installation.
Summary of the Invention
The present invention overcomes the disadvantages of the
prior art and provides a point and adaptor assembly secured
by a pin and lock assembly.
It is an object of the present invention to provide a
point and adaptor assembly in which the point will not become
disengaged from the adaptor during use.
It is a further object of the present invention to
provide a method for assembling and disassembling a point to
an adaptor.
According to the present invention then there is provided
a coupling means for an excavation tooth assembly for
removably retaining an excavation point onto an adaptor
comprising at least one sleeve receivable within the adaptor,
said sleeve being held in a non-rotational position, and at
least one pin receivable within said sleeve and at least
partially retained within said point for coupling the point
to the adaptor.
The present invention also provides an excavation tooth
assembly comprising an adaptor having at least one opening
therein; a point removably coupled to the forward end of said
adaptor and having at least one opening smaller than and
aligning with said opening in said adaptor; at least one
sleeve receivable within said adaptor opening held in a non-
rotational position and maintained within said opening by the
wall of said point; and at least one pin receivable through
said opening in said point and into said sleeve whereby at
least part of said pin is retained within said point.
The present invention also relates to a method of locking
a point to an adaptor comprising the steps of inserting a
sleeve having a ring cavity into an opening in the adaptor in
a non-rotational position, placing an expandable lock ring in
-- 3
2161505
said ring cavity of said sleeve, placing the point having an
opening aligning with said sleeve onto the forward end of the
adaptor, inserting a tapered pin having a ring groove through
said opening in the point and through said lock ring into said
sleeve whereby said pin extends from within said point into
said sleeve and whereby about half of the thickness of said
lock ring is retained within said ring groove in said pin
thereby locking the point onto the adaptor.
Brief Description of the Drawings
Preferred embodiments of the present invention will now
be further described and will be better understood when read
in conjunction with the drawings in which:
Figure 1 is a plan view of one embodiment of the point
and adaptor assembly.
Figure 2 is a sectional view taken along axis A-A in
Figure 1.
Figure 3 is a cross sectional view taken along axis B-B
in Figure 1.
Figure 4 is a plan view of the pin assembly shown in
Figure 1.
Figure 5 is a cross sectional view taken along axis C-C
in Figure 3.
Figure 6 is a plan view of the lock ring shown in Figure
5.
Figure 7 is a front view of the assembly in Figure 1.
Figure 8 is a side view of the assembly in Figure 1.
Description of the Invention
Referring to the drawings, Figures 7 and 8 show a model
of one embodiment of the excavation tooth assembly of the
present invention. As seen in Figure 1, the present invention
comprises an excavation point 3, an adaptor 5 and two pin
assemblies 7. The pin assemblies 7 lock the point-3 onto the
adaptor 5. One pin assembly 7 is located at each side of the
-- 4
2 1 ~
point 3. The pin assemblies 7 extend through the point 3 and
into the adaptor 5. The pin assemblies 7 are preferably
located in the ear 9 of the point 3 where the point 3 is
thickest and the relative wear loss during use is lowest.
This location allows the most material to be worn from the
point 3 before the assembly fails in service.
Figures 2 and 3 illustrate the arrangement of the pin
assemblies 7 within the point 3 and adaptor 5. The point 3
and adaptor 5 have openings 11, 13 which are adapted to
receive the pin assemblies 7. The openings 11, 13 are
positioned so that the sleeve 17 is located on the center axis
of inertia of the adaptor to minimize point rocking on the
adaptor.
The pin assemblies 7 are comprised of a pin 15, sleeve
17, and locking means 19. The sleeve 17 is internally
threaded. It is designed to be retained in a non-rotational
position within the sleeve receiving opening 13 in the adaptor
5. The outside contours of the sleeve 17 and the sleeve
receiving opening 13 are tapered to ensure the sleeve 17
slides easily within the opening 13 and to simplify
manufacturing. When the point 3, adaptor 5 and pin assemblies
7 are assembled in an operative position, the sleeve 17 will
align with the pin receiving opening 11 in the point 3. The
pin 15 is threaded into the sleeve 17. The shoulder 21 of the
pin 15 is supported within the pin receiving opening 11 in the
point 3. The pin 15 extends from within the sleeve 17 in the
adaptor 5 to nearly through the pin receiving openings 11 in
the point 3 to prevent the point 3 from disengaging from the
adaptor 5 while in service. The pin 15 has a tapered design
and is preferably made from a hardened low alloy steel. It
has a standard bolt head 45 to assist in inserting and
removing the pin from the sleeve. The diameter of the pin 15
must be large enough to support the constant shearing stress
between the point 3 and the adaptor 5.
2 1 6 1 505
The sleeve 17 is designed to center itself within the
sleeve receiving opening 13 and preferably the contours of the
sleeve 17 and opening 13 are complementary. The sleeve 17
does not need to fit tightly within the sleeve receiving
opening 13 in the adaptor 5. The adaptor 5 is shown in Figure
2 with face contours 25, 26, 27 on the sleeve receiving
opening 13 corresponding to the contours of the sleeve 17 to
retain the sleeve 17 in position. In Figure 4, the sleeve
receiving opening 13 has oval face contours 31, 32, 33, 34 to
prevent the sleeve 17 from rotating while the pin 15 is
threaded into the sleeve 17. Other embodiments to secure the
sleeve 17 in the adaptor and to prevent rotation are
contemplated. For example a keyed interlocking arrangement
or a threaded connection between the sleeve 17 and adaptor 5
may be used.
The sleeve receiving opening 13 in the adaptor 5 extends
through the center of the adaptor 5 to allow for a continuous
opening throughout as shown in Figures 2 and 3. This design
allows the base of the pin 15 to extend beyond the base 35 of
the sleeve 17 without conflicting with the adaptor walls,
thereby allowing one pin size to be utilized with a range of
point 3 and adaptor 5 sizes. It also simplifies the casting
design and improves the casting fitting quality because the
mould core aligns on both sides rather than only one side.
When the pin assembly 7 is installed, the inside walls
37, 38 of the point 3 and the outside walls 39, 40 of the
center portion of the adaptor 5 fit together. The inner
surface 37 of the point 3 overlaps the outside surface 28 of
the sleeve 17, thereby retaining the sleeve 17 in place during
service. The face plate 29 of the sleeve 17 remains flush or
below the adaptor surface 39 to prevent the inside surface 37
of the point 3 from damaging the sleeve 17. The pin receiving
openings 11 are perpendicular to the primary wear surfaces 41,
42 to further protect the pin 15 from damage during use of the
point 3 and adaptor 5.
-- 6 --
2 1 6 ~ 505
As shown in Figure 5, the pin assembly 7 has locking
means 19 to retain the pin 15 in the sleeve 17 during service.
The locking means 19 includes a lock ring 50. The lock ring
50 shown in Figure 6 has a small opening 58 to allow the ring
50 to expand to fit over the pin shoulder 21 and into the ring
groove 52 of the pin 15. After the sleeve 17 is inserted into
the sleeve receiving opening 13 in the adaptor 5, the ring 50
is placed into the cavity 55 of the sleeve 17. The cavity 55
is large enough to allow the lock ring 50 to be placed in the
cavity but small enough to retain the ring 50 in position over
the pin entrance 57 in the sleeve 17. The cavity 55 also
prevents the lock ring 50 from contacting the inside surface
37 of the point 3. The point 3 is placed over the adaptor 5.
As the pin 15 is inserted into the pin receiving opening 11
through the lock ring 50 and into the pin entrance 57 in the
sleeve 17, the expandable lock ring 50 is forced up the
tapered shoulder 21 of the pin 15 and into the ring groove 52.
The ring groove 52 holds the lock ring 50 in place. Part of
the lock ring 50 is positioned within the ring groove 52 and
the r~m~;n;ng lock ring 50 is left in the cavity 55. Should
the pin 15 loosen during use of the point 3 and adaptor 5, the
positioning of the lock ring 50 prevents the pin 15 from
backing out the sleeve 17. When the point 3 needs to be
replaced, the pin 15 can be removed by applying a strong
torque force to the bolt head 45. This force causes the pin
15 to unthread from the sleeve 17. The lock ring 50 is forced
against the top of the cavity 55 of the sleeve 17 and will be
pushed out of the ring groove 52 and onto the pin shoulder 21
releasing the pin 15.
The present invention also includes the method of joining
the point 3 onto the adaptor 5 comprising inserting an
internally threaded sleeve 17 into the opening 13 in the
adaptor 5; placing an expandable lock ring 50 into the cavity
55 in the sleeve 17; placing the point 3 over the adaptor 5;
and threading the pin 15 into the sleeve 17 thereby forcing
-- 7
2161505
the lock ring 50 up the pin shoulder 21 and into the ring
groove 52 on the pin 15.
While the invention has been described with reference to
one preferred embodiment, those skilled in the art will
appreciate that modifications and alterations may be made
without departing from the scope of the invention. Therefore,
it is intended that the invention should not be limited by the
foregoing description.
