Note: Descriptions are shown in the official language in which they were submitted.
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Descri~tion
Tooth AssemblY With Leaf Sprinq Retainer
Technical Field
This invention relates generally to a tooth
assembly having a tooth, an adapter and a retaining
mechanism and more particularly to a retaining
mechanism including a leaf spring for s~ecuring a pin
in its assembled position.
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Backqround Art
Tooth assemblies normally include a tooth
and an adapter which are secured one to the other with
some form o~ a retaining mechanism. In most cases the
retaining mechanism includes a pin and some form of
retainer to secure the pin in its assembled position.
Many different retainers are used to secure the pin in
its assembled position. In some of these
20 applications, the retainer is in the form of a bent ~ -
spring member that is placed in the hole in parallel
relationship with the pin and during assembly is ~ -
forced to be compressed between the side wall of the
pin hole and the pin itself, thus, imparting a force
on the pin to secure the pin in its assembled
position. In these applications, the pin nole is by
design made larger to accommodate both the pin and the
retainer, thus, weakening the nose of the adapter.
Furthermore, in these applications it is difficult to
obtainithe necessary retaining force on the pin while
simultaneously maintaining the useful life of the
retainer. By using a bent or ~ormed retainer, it is
more difficult to obtain the retaining force needed
while simultaneously maintaining the useful life of
the retainer. Likewise, the use of a bent or forme
retainer would normally require a larger retainer
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opening, thus, resulting in a weaker cross-section in
the nose of the adapter.
The present invention is directed to
overcoming one or more of the problems as set forth
above.
Disclosure of the Invention
In one aspect of the present invention, a
tooth assembly is provided and includes a tooth, an
adapter, a leaf spring, and a pin. The tooth has a
pair of aligned openings and a cavity disposed between
the respective openings of the pair of aligned
openings. The adapter has a nose portion operative to
mate with the cavity of the tooth and defines a plane
therethrough. A pin opening is aligned substantlally
along the plane and the retainer opening is offset
from and parallel to the plane while being aligned
transverse with and intersecting the pin opening. The
adapter also has a pair of contact areas located
thereon with each one of the pair of contact areas
being located on opposite sides of the pin opening.
The leaf spring is substantially flat and has opposite
end portions and is disposed in the retainer opening
of the adapter in operative contact with the pair of
25 contact areas. The pin is disposed in the aligned -
openings and the pin opening and is operative to
secure the tooth to the adapter. The pin is also
operative to engage the leaf spring generally between
the pair oE contact areas forcing the leaf spring to -
abut the respective contact areas and to forcibly flex
the leaf spring, thus, effectively imparting a holding
force on the pin. This holding force on the pin urges
the pin against portions o~ the inner surface of the
pair of aligned openings or the pin op~ning.
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The present invention provides a tooth
assembly that has a retaining mechanism which includes
a pin for securing the tooth to the adapter and a
transversely disposed substantially flat leaf spring
that is effective to impart a retaining force onto the
pin to secure the pin in its assemhled position and to
push the tooth tight onto the adapter nos~. By using
a substantially flat leaf spring, the size of the
opening necessary to locate the leaf spring is
reduced. Futhermore, the material removed from the
adapter nose to produce the opening for the leaf
spring is being removed along the neutral axis oP the
applied forces. The neutral axis being located
substantially mid-way between the upper and lower
surfaces of the adapter nose. Consequently, the
weakening o~ the nose portion created by the lea~
spring opening is reduced. Likewise, the ability to
use a flat leaf spring is enhanced by having the leaf
spring opening transverse to the pin op~ning.
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Brief Description of the Drawinqs
Fig. 1 is a diagrammatic representation of a
tooth assembly illustrating all elements in their -
unassembled condition; ;
Fig. 2 is a sectional view of the components
of Fig. 1 in their assembled position and taken along
a plane parallel to the axis of a retaining pin;
Fig. 3 is a cross-sectional view of the
elements of Fig. 1 in their assembled position taken
along the line 3-~3 of Fig. 2; and
Fig. 4 is an enlarged fragmentory portion
similar to Fig. 2 but illustrating another embodiment ~ -
of the present invention.
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sest Mode for Carryinq Out the Inventio:n
Referring to the drawings, more particularly : .
to Figs. 1, 2 and 3, a tooth assembly 10 is shown.
The tooth assembly 10 includes a tooth 12, an adapter
14, a pin 16, and a substantially flat leaf spring 18.
The tooth 12 has a forward end portion 22 operative to
engage the material being worked and a rearward end
portion 24 operative to connect the tooth 12 to the
adapter 14.
A cavity 30 is defined in the rearward end
portion 24 of the tooth 12 and extends from the ;
rearward end of the tooth 12 inwardly towards the
forward end portion 22. ~ pair of aligned openings
26,28 having an inner surface 29 is defined in the
rearward end portion 24 of the tooth 12 ln
intersecting relations to the cavity 30.
The adapter 14 has a nose portion 34
defining a pin opening 38 having an inner sur~ace 39
and a transverse vertical plane 36 generally through :
20 the center of the pin opening 38. A retainer opening -~
40 is defined in the nose portion 34 offset from and
parallel to the plane 36 and aligned transverse to and :.
intersecting the pin opening 38. A pair of contact : :
areas 42,44 are located in opposite ends of the
25 retainer opening 40. The retainer opening 40 has an ~
inner surface portion which is spaced from and flares :
away from the plane 36 and extends along the entire .:-
length of the retainer opening 40. Beginning at one
end ofithe retainer opening 40, the surface of the
30 portion 46 flares away from the plane 36 to ~ ::
progressively enlarge the retainer opening 40 towards
the mid point of the adapter nos~ 34. From the ~ :
midpoint of the adapter nose 34 to the opposite end of
the retainer opening 40, the surface of the portion 46
flares in a direction towards the plane 36 to
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progressively decrease the size of the retainer
opening 40. The size of the retainer opening 40 at
its opposite ends is equal. The pair of contact areas
42,44 are formed generally near the opposite ends of -
the portion 46.
The flat leaf spring 18 has opposite end
portions 52,54 and is disposed in the retainer opening
40. The opposite end portions 52,54 is in operative
contact with the pair of contact areas 42,44. The
flat leaf spring 18 has a generally rectangular cross-
section with the corners along the entire length of
one side thereof being beveled. However, it is
recognized that the cross section could be rectangul~r
without departing from the essence of the invention.
The flat leaf spring 18 is a steel material
having a carbon content of at least 0.5 percent and is
hardened in the range of Rockwell C40 to 50. The -
section modulus of the leaf spring 18 is in the range
of 50 mm cubed (0.003 inches cubed) to 940 mm cubed
(0.060 inches cubed). The maximum amount of
deflection in the leaf spring 18 without permanent -
deformation is in the range of 3 mm (0.125 inches) to
12.7 mm (0.500 inches). It is recognized that there
is a direct linear relationship between the width of
the leaf spring 18 and its section modulus. For
example, if the width of the leaf spring 18 is
increased two times for a given thickness, the section
modulus is likewise increased two times. ~here is
; also a relationship between the thickness of the leaf
30 spring and the section modulus. For example, if the - i~
thickness of the leaf spring 18 is increased two ~ -
times, the section modulus is increased four times.
Likewise, if the thickness of the leaf spring 18 is
increased three times, the section modulus is
increased nine times. As is well known, this is based
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on the fact that the section modulus increases as a
square of the increase in the thickness of the leaf
spring 18. When considering the amount of deflection
of the leaf spring 18, for a given length and within
its plasticity limits, as the section modulus
increases, the amount of deflection decreases. A
typical yield strength for the material of the subject
leaf spring 18 having a hardness in the range of
Rockwell C33-50 is in the range of 1000 MPa (150,000
psi) to 1585 MPa (230,000 psi).
The pin 16 defines a central groove 58 on
its peripheral surface and is disposed in the pair of
aligned openings 26,28 and the pin opening 38. The
pin 16 i5 opexative to secure the tooth 12 to the
adapter 14 by engaging the leaf spring 18 generally
midway along the length of the leaf spring 18 f~rcing
the opposite end portions 52,54 thereof to abut the
respective contact areas 42,44 located at opposite ;
ends of the retainer opening 40. The central groove
58 of the pin 16 has sloped sides operative to mates
with the leaf spring 18 allowing it to return towards -
a normal flat position once the pin 16 has been moved
to its fully installed position. The useful life of -
the leaf spring 18 is substantially increased by
allowing the amount of deflection to be lowered. This
is true since the life of a material is directly
related to the amount of stress that the material is
being subjected to for a given period of time.
! ' Consequently, if the stress level is high, the useful life is shorter and if the stress level is low, the
useful life is longer. Therefore, once the pin 16 is
installed the leaf spring 18 is maintained under a
lower stress level but in order for the pin 16 to be
removed during use or subsequent thereto, a larger
force must be applied to cause the leaf spring 18 to
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flex outward again. The higher stress levels on the
leaf spring 18 are being subjected thereto only
briefly during installation and removal of the pin 16.
Consequently, the useful li~e of the flat leaf spring
is increased.
As illustrated in the subject embodiment,
the force of the leaf spring 18 acting on the pin 16
is transferred to the tooth 12 through the inner
surface 29 of the pair of aligned openings 26,28
forcing the tip 12 into intimate contact with the
adapter nose portion 34. In the subject embodiment,
the end of the nose portion 34 is in abutting contact.
with the tooth 12 at the bottom of the cavity 30.
However, it is recognized that the abutting contact
between the tooth 12 and the nose portion 34 could b~
at other locations without departing from the essence
o~ the invention.
Referring now to Fig. 4, another embodiment
of the subject invention is illustrated. All like
20 elements have like element numbers. A pair of lugs~ `
60,62 is disposed on the tooth 12. One lug 60 is
located in the one aligned opening 26 and extends from `
the inner surface 29 thereof. The other lug 62 is
located in the other aligned opening 28 and extends
from the inner surface 29 thereof. Each of the lugs
60,62 is located on a portion of the inner sur~ace on
the side of the plane 36 that is opposite to the leaf
spring 18.
The pin 16 defines a pair of grooves 64,66
on t~e peripheral surface thereof. One groove 64 is
located adjacent one end of the pin 16 and the okher
groove 66 is located adjacent the other end of the pin
16. The pair of grooves 6~,66 are adapted upon
assembly to receive the pair of lugs 60,62 located in
35 the aligned openings 26,28 of the tooth 1~. It is
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211933~
recognized that the shape of the lugs 60,62 and their
mating grooves 64,66 could be different; than that
illustrated without departing from the essence of the
invention.
It is recognized that various forms of the
tooth assembly could be utilized without departing
from the essence of the invention. FOI' example, the
central groove 58 could be omitted. Likewise, the
pair of contact areas 42,44 could be located along the -
length of the retaining opening 40 inwardly from each
end thereof to increase the force needed to deflect
the leaf spring 18. Furthermore, even though the
invention as previously described includes the tooth
12 being connected to an adapter 14, it is well
recognized that the subject invention, as claimed,
would al50 include the connection of an intermediate
member to an adapter without departing from the
essence of the invention. In systems including a tip,
an intermediate adapter and an adapter connected to
the implement, the same type of pin and retainer could
be utilized to connect the various components.
Additionally, even though in the drawings the pin 16
is illustrated as being in contact with the inner
surface 29 of the pair of aligned openings 26,28, it
is recognized that the pin 16 could be held in contact
with the inner surface 39 of the pin opening 38 of the
nose portion 34. It is recognized that in this case
the tooth 12 would not necessarily be held tightly
against the nose portion 34. It is also recognized
that the cross sectional shape of the pin 16 could be
varied without departing from the essence of the
invention. For example, the shape could be square,
rectangular, hexagonal, or others. By using shapes
other than round, the respective grooves 58,64,66 as
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required could be simple slots located on one side
thereof only.
Industrial APplicability
In the operation of the tooth assembly 10,
the leaf spring 18 operates to maintain the pin 16 in
its assembled position, thus, securing the tooth 12 to
the adapter 14. This is accomplished as follows. The
leaf spring 18 is inserted into the retainer opening
40 followed by the tooth 12 being placed on the
adapter 14 such that the adapter nose 34 fits into the
cavity 30. Once the tooth 12 is mounted on the
adapter 14, the leaf spring 18 is trapped within
retainer opening 40 by the sides of the tooth 12. The
pin 16 is inserted into one of the aligned openings
26,28 and progressively directed into the retainer
opening 40 until one end of ~he pin 16 contacts the
leaf spring 18. The leading edge of the pin 16 - ~
contacts a corner of the leaf spring 18 inhibiting --
further movement of the pin 16 into the pin opening
38. An external force is applied to the end of the
pin 16 forcing the pin 16 past the leaf spring 18
causing the leaf spring 18 to flex. The leaf spring
18 is forced to flex to a point at which the
25 peripheral surface of the pin 16 passes by the one -
side of the leaf spring 18 that is in contact with the
pin 16. Once the pin 16 reaches its ~ully assembled
position, the leaf spring 18 drops into the central
! ' groove 58. At this position, the stress on the lea~
spring 18 is lowered and the pin 16 is securely
maintained in its installed position. The leaf spring
18 is still in a partial flexed condition such that a
continuous ~orce is being applied to the pin 16 and
subsequently to the inner surface 29 of the pair of
aligned openings 26,28. This force being sufficient
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to force the tooth 12 to firmly abut the nose portion
34.
Many times during the working of the tooth
assembly 10, the tendency of the tooth to move with
respect to the adapter is sufficient to cause the pin
16 to attempt to "walk" itself out of its originally
installed position. This working force. on the pin 16
is offset by the added force necessary to cause the
leaf spring 18 to flex to a degree sufficient for the
leaf spring to become free of the central groove 58.
Consequently, the pin 16 is securely held in its
installed condition and an external force must be
applied to one end thereof sufficient to flex the pin
18 outwardly to free itself from the central groove
58.
In one example, the flat leaf spring 18 has
a hardness of Rockwell C42, a length of 206 mm ~8.12
inches), a width of 35 mm (1.38 inches~ and a
thickness of 6.35 mm ~0.25 inches). The material
having a yield strength of approximately 1170 MPa
(170,000 pounds per square inch). With a deflection
of 6.35 mm (0.25 inches), the resulting force on the
pin 16 is approximately 5 kN tl200 pounds). As
previously noted, changes in the steel properties
result in changes in the force level acting on the pin
16. For example, if the yield strength of the above
noted flat leaf spring 18 is approximately 1585 MPa
(230,000 pounds per square inch) with a deflection of
! 8.6 mm (0.31 inches) and a hardness of approximately
Rockwell C50, the resulting force acting on the leaf
spring 18 would be approximately 7.2 kN (1630 pounds).
Referring to the operation of Fig. 4, the
assembly and disassembly of the respective components
are the same and the functioning of the various
components are the same. However, in the arrangement
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illustrated in Fig. 4, in order to assembly and/or
remove the pin 16, a larger external force has to be
applied assuming the various components are of the
same size and of the same materials of that described -
with respect to Figs. 1-3. The added force is
necessary since the pin 16 must be moved to one side
of the pair of aligned openings 26,28 in order for the
pair of grooves 64,66 to be moved to a position to
receive the pair of lugs 60,62. This extra off-center
movement likewise results in the leaf spring 18 being
forced to deflect a greater amount which increases the
force needed to cause the extra deflection of the leaf
spring 18. Even though Fig. 4 shows a pin 16 having a
central groove 58 and a pair of grooves 64,66 located
thereon, it is recognized that the central groove 58
could be eliminated without departing from the essence
of the invention. Furthermore, it is recognized that
only one lug 60 and one corresponding groove 64 could
likewise be utilized without the need of the other lug
62 and corresponding groove 66 and/or the central
groove 58. - -
In view of the foregoing, it is readily
apparent that the structure of the present invention
provides a tooth assembly having a retaining mechanism
that is both simple in constxuction and is sufficient
to provide high retaining forces to the pin that is
securing the tip to the adapter. Additionally, by
having the retaining opener 40 transverse to the pin
opening 38, a flat leaf spring 18 can readily be
utilized.
Other aspects, objects, and advantages of
this invention can be obtained through a study of the ~ :
drawings, the disclosure, and the appended claims.
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