Note: Descriptions are shown in the official language in which they were submitted.
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EXCAVATOR TOOTH, LOCK. ADAPTER
Technical Field
[0001] The invention relates to a method of affixing an excavating
tooth to an adapter for use on buckets for mass excavation equipment
used to dig and move earth and rock material.
Back r
[0002] For years construction and mining establishments have used
teeth on mass excavation equipment such as front end loaders, back
hoes, rippers and draglines. Initially teeth for mass excavation
equipment were made of a single unitary piece. When the one piece
tooth became dull or broken, a tremendous amount of time was required
to remove the tooth. Replacing a single tooth was very expensive in
time and material since 60 % -80 % of the old tooth was not damaged but
was replaced along with the problematic part of the old tooth. If the
tooth was not replaced, the tooth continued to get increasingly blunt and
unproductive .
[0003] Some of the difficulties of the unitary tooth system have
been minimized in a two part tooth system where the two parts are a
tooth (also known as a point) and an adapter. Early two piece teeth
systems posed many problems. A shell type structure was prone to
breakage. Many two piece teeth were of a delta design wherein the
adapter nose and the point socket were predominantly triangular in
shape, which when a digging force was exerted on the end of the tooth,
an internal part of the tooth would walk off the mating surface, thereby
exerting a shearing force on the locking mechanism. Locking
mechanisms such as vertical pins would elongate and shear under these
circumstances. The point would then break off or the nose of the
adapter would shear at the pinhole.
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[0004] Tooth breakage would often result in the mating surface of
the adapter being destroyed through exposure to material flow.
Shearing of the adapter nose resulted in adapter destruction due to
breakage. In both cases, the adapter would have to be replaced and
would result in significant loss of production. In many operations, such
as mining operations, the breakage and loss of the tooth was secondary
to the possible cost incurred if the lost tooth was not recovered and
resulted in a breakage of more valuable processing equipment.
[0005] To reduce problems associated with tooth breakage, a
number of two piece arrangements have been devised that include
vertically driven locking devices . These devices have often been
unsuccessful, struggling with pin shearing problems and resulting losses
of teeth.
[0006] Manufacturers have reduced breakage by designing
massively oversized nose pieces of the edges and providing significantly
larger pins in order to prevent breakage of either the tooth or nose
piece. The oversized nose pieces and larger pins have led to ineffective
digging. Further, if a larger pin was used on a smaller nose, nose
breakage would usually occur. This was undesirable.
[0007] Canadian patent application no. 1,172,287 to Hahn et al.
discloses a two part excavating tooth system wherein the nose of the
adapter has four to six helical ribs (or threads). The ribs are nearly
square-sized and non-uniform in cross-section along their length. The
top of the nose is as wide as the bottom of the nose, which can be
undesirable for balancing the stress of a load.
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[0008] There exists a need for a successful mounting system for
connecting a tooth and the nose of an adapter in a two or more piece
excavating tooth system.
[0009] There exists a need for a two piece tooth system having a
smaller, stronger and more frictionless nose design which will result in
fewer tooth breakages and fewer losses of teeth.
Summary of Invention
[0010] The past fifty years have seen many mounting methods for
a tooth on an adapter. Significant numbers of two piece systems have
featured a wedge-shape style that has a female wedge-shape socket at
the rear of a tooth which slides over a corresponding wedge-shaped
nose.
[0011] Our invention provides a new excavator tooth, lock and
adapter using a modified rope design. A common rope is of a 6/19
arrangement, meaning that a core of 6 stands of straight rope is
angularly encircled by 19 strands of rope extending the length of the
rope in a angular fashion around the core. Our design is much simpler
in that we have only one modified centre core that is cone-shaped with
three angular raps around the centre core.
[0012] Our nose incorporates a stress beam at the blind end of the
nose. The stress beam takes up stress from the tooth when a digging
force is applied to the digging end of the tooth. Our stress beam
strength is enhanced by two of the three outside strands of the rope
structure. The three twine structure has greatly improved the locking
system due to our system not putting the lock pin in direct shear.
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[0013] The improved twine and locking system puts it in diagonal
compression, meaning that in order to fail it would virtually have to be
extruded out of its position. Because of this we can incorporate a
smaller pin and nose section. The integrity of the nose is enhanced
since there is no large hole in the centre of the nose for a large locking
pin, therefore the nose is not nearly as likely to shear. Further, our
nose forms an equilateral triangle with the base forming the largest
parallel plane to the highest stress point on the tooth at its rear bottom
extremity. This provides the tooth with a greater area to dissipate
stress. Our tooth has one ear which, unlike most tips, is made parallel
to the cone, not the side of the adapter. This is done in order to not
jeopardize the integrity of the adapter with a deep cut into the nose for
the locking device. Rather, the cut is made in the much heavier section
of the adapter. Since our locking pin is vertical (although it does not
necessarily have to be) as most pins are, the pin is easily removed when
no force is exerted on the tooth.
[0014] To remove the pin, a little force is required to drive it
down. Our pin does not require a positive static locking device, as do
most vertically arranged noses, because it is in compression when in
use. A horizontal pin (an alternative locking device) is much less
desirable because it bisects the nosepiece and is most difficult to remove
when changing a tooth since little room can generally be found between
the teeth.
[0015] Since our pin can be easily removed, time and money can
be saved. Our pin is essentially in two parts, one steel with a two-part
polymer insert, the inner part of the polymer being resilient and foamy
and the outer part that locks into the recess in the tooth extremely hard
but not hard enough to fracture under either load or cold temperature.
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Brief Description of Drawings
[0016] In drawings that illustrate non-limiting embodiments of the
invention:
Figures 1, 2 and 3 are end views of adapters according to
embodiments of the invention;
Figure 4 is a side view of an adapter in accordance with an
embodiment of the invention, the adapter having front and rear
stabilizers;
Figure 5 is a top view of the adapter of Figure 4;
Figure 6 is a rear end view of a tooth having an ear and having
grooves for receipt of the threads of an adapter;
Figure 7 is a side view of the tooth in figure 6 having receiving
pockets in the tooth cavity and a locking pin recess;
Figure 8 is a side perspective of a locking device in accordance
with an embodiment of the invention;
Figure 9 is a cross sectional view of a locking device embodiment
engaged to an ear of a tooth in accordance with an embodiment of
the invention;
Figure 10 is a perspective view of an adapter, tooth and locking
device;
Figure 11 is a cross-sectional view of a tooth and adapter in fully
engaged position.
Description
[0017] Throughout the following description, specific details are
set forth in order to provide a more thorough understanding of the
invention. However, the invention may be practiced without these
particulars. In other instances, well known elements have not been
shown or described in detail to avoid unnecessarily obscuring the
invention. Accordingly, the specification and drawings are to be
regarded in an illustrative, rather than a restrictive, sense.
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[0018] The design and evolution of the adapter 105 nose 130 is
represented in Figures 1 through 3. The nose design 130 was essentially
derived from a rope formation with a center core 162 and three outer
twines of rope 150 all modified to form a cone-shape, and further
modified to develop stabilization. Three twines or ribs 150 were
selected to enable us to develop a large bearing surface on the back
bottom section of the tooth while maintaining a fiction free top section.
[0019] Our excavating tooth system 100 shown in Figure 10
comprises an adapter 105, locking device 115 and tooth 110. The
construction consists of a base with a nose portion 130 arranged in a
tripod formation, forming an equilateral triangle 165. This allows for a
narrow topside for penetration and a double-wide base for a bearing
surface when the tooth 110 is subjected to stress. Tapered section cords
150 have a cylindrical angular-shape, which rotates the tooth 110 during
assembly to the nose 130, thereby ensuring that once the locking device
(pin) 115 is installed and force is transformed to the tip, the locking
device 115 is under side compression holding it firmly in place. The
end beam stabilizer 160 and the locking slots form the same angular-
shape. It transfers force from adapter 105 to tooth 110 and stabilizes the
tooth 110. The general shape of the nose 130 with the three wide
modified sectional cords 150 and conical bearing base give us one of the
strongest assemblies possible.
[0020] Certain dimensions of the embodiment of the adapter 105
shown in the figures 4 and 5 are described herein with reference to a
center line 170 that extends longitudinally through the center of adapter
105. The angles 175 upon which the ribs 150 and the stress beam 160
of adapter 105 are rotated in relation to the center line 170 are
approximately 22. 5 ° . The angle 240 that the outer edge of the center
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cone 155 forms with the center line 170 is approximately 22 ° . The
angle 245 formed from the inner edge 250 of the angled retainer slot (or
channel) 125 to the center line 170 is approximately 17.2 ° . Rear
stabilizers 168 form an angle 172 of 50 ° from the center line 170. The
examples provided will result in an angular rotation of the tooth 110 by
22.5 ° about the center line 170 relative to the adapter 105 for
engagement or disengagement.
[0021] Generally a tooth 110 is either worn out and has to be
replaced or it is lost because of failure of the locking device 115. Our
design minimizes or completely avoids the latter since our angular
modified cords 150 create a situation whereby the locking device 115 is
not put in total shear as with most other designs. Our locking device
115 is primarily put in angular compression thereby significantly
reducing or eliminating pin shear and tooth loss.
[0022] The top and bottom surfaces of the adapter slope
downwards toward the free end of the adapter (Fig. 5).
[0023] The adapter has three well defined modified directional
cords 150 at 1 /8 of revolution, or 22.5 ° , sloping from a location
starting about lh of the distance from the front of the nose. These
tapered sectioned cords 150 can be formed to start from a position and
extending through to the rear of the nose 130. These cords 150 can
either be formed to start from a position extending left to right or right
to left (i.e. extending in a clockwise or counter clockwise direction
about the nose) .
[0024] The angled retainer slot 125 is located at the back of the
nose 130, although the angled retainer slot could be located on the left
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side, right side, top or bottom of the nose depending on the location of
the corresponding single extended ear 140 on the excavating tooth 110.
[0025] The rear section of the adapter nose 130 is unique in that it
forms a reverse angle as a result of a 22 . 5 ° (from the horizontal
center
line at front view) segment of an arc formed at the rear section of the
nose 130 and extends at an angle of approximately 50° upwards (Fig.
4). This forms a resulting third bearing service or rear stabilizers 168 to
take up stress on the tooth 110 when it is in a digging mode. This is
advantageous in that most designs only utilize two bearing surfaces as
opposed to our three.
[0026] The tooth 110 is formed as a result of casting and can only
be accomplished in this manner because of the three twining sectioned
cords 150 around the center core 162.
[0027] The tooth 110 is cast and forms a blind cavity 135 with the
large opening of this cavity 135 facing to one end and generally angling
down to the blind end (Fig. 11). The tooth 110 incorporates an angular
stabilizer 230, which is generally horizontal, extending from the center
of the end of the cone on both corners and incorporating an angular
gusset of 22 ° in a continuation of the cords to strengthen and
harmonize
the existing cords allowing the tooth 110 to move on to the nose 105
effortlessly (Fig 5) .
[0028] The cavity 135 of the tooth 110 generally conforms to the
mating surfaces of the nose 105 consisting of a beam stabilizer 230 at
smallest end of the cavity 135 and three modified female cords 225 at
22. 5 ° sloping from a position half way back in the cavity 135 to the
rear or open end of this cavity 135. The modified cords 225 may be
initiated from either from right to left or left to right (i.e. extending
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clockwise or counterclockwise) and a reversed angular surface at the
open end of the cavity 135 to mate with the adapter 105.
[0029] The tooth 110 has one extended ear 140 containing a recess
215 generally in the center of the ear 140. The ear 140 can be located
on the tooth 110 at the rear side of the cavity 135 and extends rearward
of this cavity 135. The ear 140 can also be located at the top, bottom
or either side of the rear cavity 135 depending on the desired locking
position.
[0030] The locking device or pin 115, for locking the tooth 110 to
the adapter 105, has a rigid shell 222, which may be made of steel
construction, with a recess formed in such a way as to allow a dual
polymer insert 220 to slide into place. The lock itself is made of a dual
polymer. The inner section 220 is a resilient material with air bubbles
such that when the pin 115 is driven into the locked position the bubbles
are compressed and create an outward force on the non-resilient
polymer that makes the rigid polymer contact the walls of the recess in
the steel tooth 110.
[0031] The locking pin 115 when driven into position locks into
the recess 215 formed in the inside ear 140 of the tooth 110 thereby
holding the pin 115 securely in the tooth 110 in the correct position with
the adapter 105. The design of the pin 115 is such that when stress is
brought to bear on the tooth 110 it does not become ridged in the
adapter 105 but moves freely with the tooth 110.
[0032] As will be apparent to those skilled in the art in the light of
the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from the
spirit or scope thereof. Accordingly, the scope of the invention is to be
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construed in accordance with the substance defined by the following
claims .
