Note: Descriptions are shown in the official language in which they were submitted.
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Description
Ripper With ~ffset Impacting Means and Slotted Shank
Technical Field
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This invention relates generally to a ripper
and more particularly to a ripper having an impacting
mechanism and means for efficiently transmitting
impacting forces from the impactin~ mechanism to the
ripper tip.
Background Art
Impact-type rippers include an eccentric cam
which functions to intermittently apply an impacting
force to a ripper tip for rock ripping purposes. The
eccentric cam is aligned with the ripper tip to
provide an in-line application of impacting forces
thereto, via an intermediate ring-like impact member
and impact receiving member. This type of impact
ripper is fully disclosed in U~SD Patent No.
3,868,145, issued on February 25, 1975 to Delwin E.
Cobb, Et Al., and assigned to the assignee of this
application.
Although impact rippers of this type
function quite well, the solid supporting shank for
the ripper tip exhibits an impact spring rate that is
approximately eight times stiffer than the hardest
rock that can be ripped. This relatively high spring
rate induces high peak impact forces in the ripper
mechanism which could affect the desired service life
thereof. In addition, impact energy is dissipated due
to the mismatch of the mechanical impedance between
the impact member and the shank and between the ripper
tip and rock being worked.
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Furthermore, conventional impact rippers are
designed for relatively shallow cutting depthsr e. g.,
23 cm. Any attempt to offset the ripper tip from the
eccentric cam and attendant impacting mechanisms
requires a substantial lengthening of the shank, having
the ripper tip secured thereon. The mass of the shank
is increased to thus increase internal impacting forces
without any appreciable increase in the ripping forces
applied to rocks by the ripper tip. Such internal
impacting forces tend to produce high moments which
cause increased pivot pin loads and also induce ripper
tip deflections, resulting in lower cutting efficiency.
The present invention is directed to
overcoming one or more of the problems as set forth
above.
Disclosure of Invention
In one aspect of this invention, a ripper
apparatus has a movable support member, a ripper tip
mounted on the support member for movement along a
first line, and impacting means for applying an
impacting force to the support member in the direction
of a second line. The first and second lines are
disposed in offset relationship relative to each other
and spring means, between the impacting means and the
ripper tip, is provided for inducing transmission of
the above impacting force from the second line to the
first line directly.
In another aspect oE this invention, the
improvement comprises the spring means including a slot
disposed transversely relative to each of the first and
second lines.
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In still another aspect of this invention,
means is provided for inducing a matching of the
mechanical impedance between the impacting means and
the support member and between the r ipper tip and
material being
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worked. Such means is adapted for use with ripper
apparatus wherein the above first and second lines are
offset or co-incident.
The impact apparatus of this invention i5
highly efficient in operation and is capable of making
deep cuts, e.g., 51 cm. in depth. The apparatus
functions to decrease the impact spring rate which, in
turn, promotes efficient energy transmission and
lowers internal impacting forces to prolong the
service life of the components of the ripper
apparatus. The cutting portion of the support member
or shank is substantially relieved of any bending
moments to provide the leading edge of the shank and
ripper tip with a high stiffness for efficiently
fracturing rocks and the like. The ripping apparatus
- of -this invention provides the above desiderata
without increasing its complexity over conventional
ripper apparatus.
Brief Description of the Drawings
Other objects and advantages of this
invention will become apparent from the following
description and accompanying drawings wherein:
Figure 1 is a partial side elevational view
of a tractor having a ripper apparatus embodiment of
the present invention mounted rearwardly thereon;
Figure 2 is an enlarged, partially sectioned
side elevational view of the ripper apparatus; and
Figures 3 and 4 are views similar to Figure
2~ but illustrate modifications of the ripper
apparatus.
Best Mode o~ Carryi-n-g--out the Invention
Figure 1 partially illustrates a track-type
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tractor 10 having a ripper apparatus 11 mounted
rearwardly thereon by a parallelogram type linkage 12.
Linkage 12 is adapted to raise and lower ripper
apparatus 11 to engage a ripper tip 13 thereof with
ground level for ground and rock ripping purposesO
Referring to Figure 2, ripper tip 13 is
detachably connected in a conventional manner to a
support member or shank 14 for impacting movement,
generally along a center line Ll thereof. ~n upper
end of shank 14 is pivotally mounted on a support
bracket 15 of ripper apparatus 11 by a pin 16.
Impacting forces are interm.ittently applied to shank
14 by an impacting means 17, such as the type
disclosed in above-referenced U.S. Patent No.
3,868,145.
In general, impacting means 17 may include
an hydraulic motor 18 having a rotary output shaft 19
secured to an eccentric cam or crankshaft 20 which is
mounted within a ring-like impact member 21. Impact
member 21 is adapted to be impacted against an impact
receiving member 22, disposed bet:ween impact member 21
and a rearward surface 23 of shank 14. Although
impact member 21 could engage shank 14 directly,
intermediate impact recei.ving member 22 is preferred
to enable the use of sealing means (not shown~ between
a housing 24 of impacting means 17 and member 22 to
prevent the escape of lubricating oil from the
housing.
It should be noted in Figure 2 tha~ center
line 1,1 of ripper tip 13 and center line L2 ~
eccentric 20 and impacting member 21 are substantially
offset relative to each other, and are at least
approximately disposed in parallel relationship.
Since shank 14 will pivot about pin 16 when impacting
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forces are applied thereto by impacting means 17, line
Ll will vary slightly from a true parallel
relationship relative to line L2 during operation.
One aspect of the present invention resides in the
offset relationship of lines Ll and L2 coupled with
the provision of a spring means 25 for inducing
transmission of impacting forces from impacting means
17 and line L2 to line Ll of ripper tip 13 directly.
In the Figure 2 embodiment of this
invention, spring means 25 includes an elongated and
triangular slot 26 formed completely through shank 14
and preferably disposed to straddle a distance D
defining surface portions on rearward surface 23 of
shank 14 which are engaged by member 22 for applying
impacting forces to the shank. Opposite ends 27 of
slot 26 are preferably relieved by circular cutouts to
eliminate the potential for any stress risers thereat.
Slot 26 thus defines a spring portion 28 on shank 14,
disposed between member 22 and slot 26, which will
deflect when impacting forces are applied to the shank
by impacting means 17.
Assuming the absence of slot 26 in shank 14,
i .ec r the shank being solid, certain functional
disadvantages would resùlt. ~or example, larger
internal impacting forces would result from the
increased stiffness and mass of the shan~. As
described more fully hereinafter, useful energy would
also be dissipated due to the mismatch of the
mechanical impedences in the system. The service life
and overall efficiency of ripper apparatus 11 would
thus be disadvantageously affected.
~ owever, the utilization of spring means 25
in the form of through-triangular slot 26 will ensure
that impacting forces applied to shank 14 by impacting
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means 17 will be transmitted substantially directly to
center line Ll of ripper tip 130 The offset
relationship of lines Ll and L2 thus facilitates the
design of a ripping apparatus which can produce
substantially deep cuts, e.g., 51 cm., with the
addition of spring means 25 ensuring that internal
impacting forces are substantially reduced. Also, the
mass of the lower section 29 of shank 14 ensures
nonbending of ripper tip 13.
Figure 2 further illustrates a pair of
standard dampers or damping means 30 and 31, mounted
on bracket 15 and disposed on either side of shank 14,
for damping oscillation of the shank. The dampers may
be spring loaded or may include a dash-pot of standard
design.
Figure 3 illustrates a modified ripper
apparatus lla wherein identical numerals depict
corresponding constructions, but with numerals
depicting modified constructions in Figure 3 being
accompanied by an "a".
Ripper apparatus lla differs from ripper
apparatus 11 in that a corresponcling spring means 25a
for inducing transmission of impclcting forces from
line L2 to line Ll dire~tly comprises a cantilevered
member 28a having its upper end secured to bracket 15
by a pair of bolts 32. Member 28a has an impact
portion 29a defined on a lower end thereof for
transmitting impacting forces along an aligned center
line Ll of ripper tip 13. Impact portion 29a is
defined by an elongated slot or recess 26a formed on a
forward side of member 28a to maintain the other
portions of member 25a in out-of-contact relationship
with respect to a rearward surface 23a of a slightly
modified shank 14a.
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~pon application of impacting forces to the
rearward side of member 28a by member 22, member 28a
will flex like a spring fork and transmit such forces
directly to ripper tip 13 via portion 29a of member
23a. Slot 26a is preferably disposed on member 28a to
straddle member 22, as depicted by distance D. It
should be further noted in Figure 3 that dampers 31 and
30 are arranged to dampen oscillation of shank 14a and
member 25a, respectively.
This arrangement allows the use of a smaller
impactor shank which, because of its weight, can be
replaced more readily than a heavier shank. It should
be noted in Figures 2 and 3 that each spring means 25
and 25a is located between the respective impacting
means and ripper tips.
Figure 4 illustrates a modified ripper
apparatus llb wherein iden~ical numerals depict
corresponding constructions, but with numerals
depicting modified constructions in Figure 4 being
accompanied by a "b".
Ripper apparatus llb differs from ripper
apparatus 11 (Figure 2) in that lines Ll and L2 are
co-incident, rather than ofEset. In this aspect of the
invention, spring means 25 functions to improve impact
energy transfer by inducing a matching o~ the
mechanical impedance between impacting means 17 and the
respective support members 14 and 14b and between
ripper tip 13 and the ma~erial or rock being worked.
The dissipation of useful energy is thereby greatly
reduced and the working efficiency (energy output
divided by energy input) of the ripper apparatus is
significantly increased in comparison to conventional
ripper apparatus having solid support members or
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shanks. Otherwise stated, the addition of spring means
25 to shanks 14 and 14b in the form of through slots 26
changes the spring rates and fundamental frequency
responses thereof to maximize the amount of
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enerqy delivered by ripper tip 13 to the rock being
worked.
In addition to providing a "softer'l shank
spring, slot 26 substantially decreases the shank
mass, e.g., by approximately 15%. Although the co-
incident alignment of lines Ll and L2 in Figure 4 does
not provide as low an impact force, as felt by the
mechanism, as the offset relationship of the lines in
Figure 2, ripper apparatus llb is substantially more
efficient than a conventional ripper apparatus having
a solid shank. Ripper apparatus llb illustrates that
the inventive concept of spring means 25 can be added
to a conventional shank to increase the performance
ef~iciency thereof, with only minor modification.
Industrial Applicab_lity
Ripper apparatus 11, lla, and llb find
particular application to track-type tractors and the
like for breaking rock. As shown in Figure 1, ripper
apparatus 11 is mounted on the tractor by a standard
2Q parallelogram-type linkage 12 whereby the ripper
apparatus can be raised, lowered, and inclined
relative to ground level for maximum cutting
efficiency.
As shown in Figu~e 2, rotation of output
shaft 19 of motor 18 will, in turn, rotate eccentric
cam 20 to reciprocate impact member 21 against member
22. The intermittent application of impacting forces
to rearward surface 23 of shank 14 by member 22 will
oscillate ripper tip 13 for rock breaking purposes.
The interposition of sprin~ means 25 between center
line L2 f eccentric 20 and center line Ll of ripper
tip 13 will ensure that substantially all of the
impacting forces applied to shank 14 will be
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transmitted to ripper tip 13 directly with a
substantially low internal impact force and that
energy transmission to the ripper tip will be
maximized.
Ripper apparatus lla and llb of Figures 3
and 4, respectively, function in a similar manner, as
described above. The o~fset relationship of center
lines Ll and L2 will facilitate the making of
substantially deeper cuts than have been heretofore
accomplished with impacting ripper apparatus wherein
such center lines are at least substantially
coincident.
Other aspects, objects, and advantages of
this invention can be obtained from a study of the
drawings, the disclosure, and the appended claims.
