Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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EXCAVATING TOOTH ASSEMBLY
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to an excavating tooth assembly
and more particularly, to an assembly featuring a novel lock
arrangement for removably securing a point on an adapter
Traditional excavating tooth locking devices depend on
enclosure within centrally located apertures in the tooth
components for development of dislodgement resistive forces.
Until the development of the HELILO ~ twist-on point (U.S.
P~tent 4,335,532) virtually all commercial teeth used a
combination of a rigid lock such as a pin and a resilient
keeper such as a plug. Historically, the rubber plug
operated through the lock to tighten the point on the nose of
the adapter and these same tightening forces maintained the
engagement of the plug with the locking pin to resist pin
ejection. The drawback in this approach was that resistance
to pin dislodgement diminished as the point/nose fit loosened
through service -- with resultant reduction in tooth
tightening forces.
The above-mentioned '532 patent did not use centrally
located apertures for containment but rather a U-shaped lock
straddling the adapter and engaging rearwardly extending
tongues on the point. This realized a significant increase
in strength over preceding teeth. Relative to the '532
patent I have inventéd a new locking system therefor which
offers several improvements and advantages over the U-shaped
fastener.
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Thus broadly, the invention pertains to an excavating
tooth assembly including an adapter nose having laterally
projecting spaced ears on only one side thereof, a point
having a rearwardly projecting tongue positioned between the
ears, with locking means consisting essentially of a vertical
pin external of the adapter nose disposed perpendicularly to
the longitudinally extending line of mounting the point on
the adapter, the pin having front and back surfaces in
wedging engagement with the ears and tongue, a bore in the
adapter transverse to the longitudinally extending line
between the spaced ears, and a resilient plug member in the
bore engaging the pin.
More particularly, the invention involves an
externally mounted elongated shaped lock which provides a
point tightening force through cooperative engagement with
two vertically disposed ears connected by a ledge on one side
of the adapter nose and with the lug on one ear of the point
through spring-like deformation from its free shape.
This lock is maintained in place by engagement with
a retractable plug centrally located in the side
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of the adapter nose. The adapter nose ears project from the
side of the nose a distance approximately equal to the thickness
of the elongated lock. The connecting ledge provides a guide
function when the lock is driven into place and then a secondary
bearing function in operation of the tooth assembly to prevent
overstressing of the lock. This ledge projects from the side of
the nose a distance of approximately half the thickness of the
elongated lock. The invention provides the following advantages
and improvements:
1. Extended lock life through a
unique stabilized wedge action;
2. Reduction of effort for lock removal;
3. Reduced cost;
4. No requirement for a dedicated lock
removal tool; and
5. Increase in adapter nose life.
The instant invention is described in conjunction with
an illustrative embodiment in the accompanying drawing, in
which --
FIG. 1 is a fragmentary side elevational view of a
tooth embodying the invention;
FIG. 2 is a top plan view of the tooth of FIG. l;
FIG. 3 is a sectional view along the line 3-3 of
FIG. l;
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FIG. 4 is an enlarged sectional view of the keeper plug
illustrated at the right-hand port:ion of FIG. 3;
FIG. 5 is an enlarged side elevational view of the
locking pin seen in the left-hand portion of FIG. l;
FIG. 6 is a front elevational view of the pin of FIG.
5;
FIGS. 7-9 are sectional views through the pin of FIG. 5
along the lines 7-7, 8-8 and 9-9 respectivelY;
FIG. 10 is a fragmentary perspective view of the
adapter employed in the practice of the invention and featuring
the right or "lockless" side;
FIG. 11 is a fragmentary perspective view of the
adapter of FIG. 10 and featuring the left or "lock-equipped"
side, and also illustrating the plug in exploded relation
thereto;
FIG. 12 is a front end view of the adapter similar to
the showing in FIG. 3; and
FIG. 13 is a sectional view taken along the line 13-13
of FIG. 2.
DETAILED DESCRIPTION
The instant invention find advantageous application in
connection with the excavating tooth of the previously-mentioned
co-owned patent 4,335,532 which has been marketed widely under
the trademark HELILOK~ . In certain instances, there has been
*U.S. Patent No.
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difficulty of removal of the U-shaped fastener. In any event,
the lock of the instant invention reduces the fairly high force
requirement required in the '532 patent for lock removal.
In the illustration given, the numeral 20 designates
generally the inventive tooth assembly. As seen in FIGS. 1 and
2 the numeral 21 designates the point element. The point 21 is
mounted on an adapter 22. More particularly, the adapter 22 has
a nose 23 (see particularly FIGS. 10 and 11) which is received
within a socket 24 (see FIGS. 1 and 2). The point 20 has a
digging or earth engaging edge or bit 25 at the end thereof
opposite the socket 24. Conventionally, the point 21 is
installed on the adapter 22 by a lineal movement along the
longitudinal center line or axis of the tooth 20.
As in the '532 patent, the point and adapter employ
generally helical thread means for achieving the coupling
between the point 21 and adapter 22. In the illustration given
the threads or helical flutes 26 are provided on the exterior of
the nose 23 (see FIGS. 10 and 11). In similar fashion, the nose
23 is equipped with a stabilized end part as at 27 and for
additional details hereof, reference is hereby made to the '532
patent.
In the operation of the '532 construction (and here as
well) the point 21 was positioned with its socket end in
alignment with the forward end of the nose. Grooves (not shown)
in the point were aligned with the threads 26 and installation
was achieved by rotating the point 21 through approximately
45. Thereafter, a generally U-shaped lock was inserted into
the two side tongues 28 (see FIG. 2). These tongues 28 extend
rearwardly of the point 21 and have slots 29 therein. The
adapter nose has mating recesses 30 to receive the tongues 28.
The tongues 28 on the point 21 enter the recesses 30 at the last
stage of point rotation incident to mounting.
The lock generally designated 31 (see FIG. 3) of the
instant invention differs significantly from that previously
employed with the '532 patent construction, consisting in the
illustrated embodiment of only a single pin as contrasted to the
U-shaped lock previously employed. The pin or lock bar is
designated 32 and is seen to be deformed as at 33 (see FIGS. 1
and 13) to provide a point tightening force.
The creation of this tightening force is facilitated by
a variable width profile consisting of a "large radius", concave
forward edge 34 and a "smaller radius", convex rear edge 35 (see
FIG. 5), For example, the pin 32 for the size 67 HELILOK~ is
5.9" long with the concave forward edge 34 being developed by a
22" radius and the rear edge or surface by a 16" radius. The
cross sectional dimensions at the ends are approximately 0.75" x
0.80" with the larger dimension extending between the surfaces
34 and 35. At mid-length, this dimension is 0.870".
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In installation of the pin 32, the forward edge 34
contacts a pair of vertically disposed ears 36, 37 which project
from one side of the modified design HELILOK~ nose (see FIGS. 1
and 11). The rear edge 35 contacts the lug 38 on one of the
point tongues 28 (compare FIGS. 1 and 2). The lugs 38 are
provided at the extreme rear of the tongues 28 and are partially
defined by the slots 29.
During assembly the relatively narrower end width of
the pin 32 (see FIGS. 5, 6 and 9 at 39) enters, without
resistance, the available opening between the point tongue lug
38 and the ledge 40 (see FIG. 12) extending between the
vertically disposed nose ears 36, 37. As the pin 32 is driven
into this opening its rear edge 35 engages the point lug 38 such
that lateral deformation of the pin 32 is induced. This elastic
deformation creates a point tightening force against the point
tongue lug.
It is the geometry of the forward edge relative to the
rear edge of the pin that produces a wedge tightening affect on
the point tongue lug. This geometry eliminates one of the
negative aspects of a traditional straight taper wedge, which is
the tendency to disassemble under load. With a straight taper
wedge, there is always a component of tooth loading tending to
dislodge the wedge. With the instant invention, there is no such
component. This geometry may be considered as providing a
stabilized wedge force by virtue of elimination of the
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dislodgement force component.
As indicated above, the pin 32 is beveled at one end as
at 39 -- for engagement during assembly with the spring plug
generally designated 41. As best seen in FIGS. 3 and 8 the pin
32 is equipped with a generally conically shaped side recess 42
which receives the end of a similarly shaped plug member 43 (see
FIG. 4). The plug member 43 is equipped with an axially
extending shank 44 about which a helical spring 45 is mounted.
Still further, the spring 45 and shank 44 are
encapsulated with a shrouding means 46 which advantageously may
take the form of self-skinning polyurethane rubber. This avoids
problems of lock removal which sometimes were difficult because
of frozen dirt which can pack around the spring in the
assembly. Also, by encapsulating the spring 45 and shank 44 in
the means 46 inward of the base 47 of the plug member 43, a
unitary element 41.
The self-skinning shroud means 46 seals out clay and
fines which hinder plug function and the shroud means is capable
of great deformation without loss of resiliency through the fact
that water is prevented from entering the foam cells.
The cooperative engagement of the pin with the plug 41
at the beginning of assembly is arranged to prevent accidental
reverse assembly of the pin. As properly oriented for assembly
the beveled end 39 of the pin 32 will engage the tip of the plug
member 43 such that, when the pin is driven toward assembly, the
total plug 41 is forced by a wedging action into the circular
bore 48 (see FIG. 11) in the side of the adapter nose and
against the pressure of spring 45. Because the conical tip 49
of the plug is joined to the flange bearing or base portion 47
of the plug by an intermediate cylindrical portion 50, this plug
wedging action will not occur when the pin is positioned in a
reverse orientation. In this instance, the blunt portion 51
(see FIG. 6) of the pin end will flatly contact the cylindrical
portion of the plug tip so that assembly is prevented. Assembly
of the pin upside down is prevented by the same means. The
beveled end 39 is equipped with an integral guide 39a as seen in
FIGS. 5 and 9 to assist the insertion of the pin 32.
Spring loaded locks have been disclosed in the prior
art, for example, U. S. Patent No. 2,635,366 but this suffers
from the drawback of having the lock retention force operating
in the same direction as the point mounting direction. Another
prior art teaching that employs detent like means for mounting a
point on the adapter is co-owned Patent 4,577,423 but no springs
are employed.
A commercially available locking system employs a
central flex pin which forces two side pins into holes in the
point sidewall, thereby giving four surfaces of point
retention. However, the side pins have nothing to do with
*U.S. Patent No.
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retaining the central flex pin in assembly.
Still another type of spring usage is seen in co-owned
Patent 4,501,079 which employs a very wide spring to achieve
only secondary tightening capability to prevent rattling.
The adapter nose rear, top and bottom profiles are
continuous uninterrupted surfaces as at 52 and 53 ~see FIG. 10)
made possible because the two ears 36 and 37 project only
sidewardly. This optimizes the nose in resistance to fatigue
failures in the area of the lock.
The ledge 40 joining the two vertically disposed nose
ears 36, 37 and formed by the termination of the conically
shaped nose is characterized by the same lateral alignment with
the point tongue lug 38 as exists in the co-owned Patent
4,335,532. This creates the same longitudinal shear loading on
the pin as exists on the U-shaped lock, wherein a pin of
comparatively small size and low cost is structurally adequate.
While in the foregoing specification a detailed
description of an embodiment of the invention has been set down
for the purpose of illustration, many variations in the details
hereingiven may be made by those skilled in the art without
departing from the spirit and scope of the invention.
*U.S. Patent No.
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