Note: Descriptions are shown in the official language in which they were submitted.
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OUICK ~Q~LER
Backqround of the Invention
l. Field of the invention.
This invention relates to couplers, and more
particularly, to couplers for quickly coupling any of a
variety of implements to the arms of front-end loaders.
2. ~escription of the related art.
Front-end loaders are powered vehicles running on
wneels or tracks having hydraulically operated arms
extending from the front of the vehicle. The arms
operate to perform useful work by means of attached
implements such as a bucket, scoop, plow, fork, or the
like. It is often desirable to quickly change imple-
ments with minimal effort by the operator, and quick
couplers have been developed for this purpose. Such
coupler systems have two mating parts: a loader portion
mounted on the arms of a front-end loader and an
implement portion which is duplicated on the bacX of
various implements so that any implement may be selected
and carried by the loader portion. ~Jsually, the
operator may disengage one implement and engage another
without leaving his or her seat.
Prior art quick couplers typically extend the
distance from the front-end loader to the center of
gravity of the implement. Some couplers have been known
to extend the distance of attachment by as much as
twenty four inches beyond its original design location.
Extending the center of gravity of the implement further
_ away from the front-end loader adversely effects the
loader's performance. Stability, tipping load, and
break-out force are all reduced by couplers that extend
the center of gravity of the payload.
In one prior art design disclosed in U.S. Patent
No. 4,708,579, an attempt was made to maintain the
original design position of the implement's center of
gravity. This design employed a contoured face plate
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which formed the ~backbone~ of the coupler. While this
design reduced the problems associated with the
extension of the implement attachment points, it
nevertheless extended the implement's center of gravity
approximately one and one half to two inches beyond its
original design location.
Front end loader manufacturers have chosen
different arm configurations on their machines.
Therefore, a quick coupler must be designed for a
lo specific brand or style of front-end loader with
respect to the locations of the arms. Many prior art
quick couplers have engagement points or pick-up points
between the two parts of the quick coupler which are
structurally related to the pivot joints where the
loader arms connect with the coupler. This design
limits a set of implements to use with a specific style
of front-end loader. If a different front-end loader is
acquired, not only must a new coupler be purchased, but
the existing implements must be altered or replaced or a
redundant set must be purchased to match the new
coupler.
Many prior art quick couplers have pick-up points
between the two coupler parts which are laterally spread
apart a substantial distance. This design has provided
adequate strength, however, a great amount of maneuver-
ing by the operator is required prior to coupling to
move both pick-up points into alignment. In particular,
when the implement to be coupled is resting on uneven
ground, a great deal of manipulation is required to
properly align the loader portion with the implement
portion. Single pick-up point couplers were designed to
permit the operator to drive up to a single self-
aligning connection point. While this design permitted
easier coupling, the strength of the connection between
the two coupler parts was compromised to permit a single
connection point.
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Many prior art couplers have a horizontal support
member mounted near the top of the coupler near where
the upper loader arms are attached. When a fork-lift
attachment is mounted to the coupler, the horizontal
support member blocks the operators view of the forX
tines making it more difficult for the operator to
align the attachment with a load.
The present invention provides a new and useful
quick coupler which overcomes the above disadvantages of
lo prior art designs.
Summary of the Invention
An object of the present invention is to provide a
quick coupler for coupling various implements to the
arms of a front-end loader without extending the center
of gravity of the implement beyond its original design
location.
Another object of the invention is to provide a
coupler having a single main support member.
A further object of the invention is to provide a
quick coupler with two centralized pick-up points
between the two coupler parts to allow rapid self-
aligning coupling and minimal operator manipulation.
A further object of the invention is to provide a
coupler having pick-up points between the coupler parts
which are structurally independent of the front-end
loader arm connection points.
Another object of the invention is to provide a
_ coupler which allows the operator optimal visibility
between the front-end loader arms.
In a preferred embodiment, the invention comprises .
a coupler adapted to join a variety of implements to a
front-end loader, the front-end loader having a
plurality of lower arms and at least one upper arm. The
arms are adapted to pivotally support the coupler. The
coupler includes a loader portion adapted to be coupled
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to the arms and an implement portion cooperating with
the loader portion and adapted to be secured to any of
the variety of implements. The coupier is pivotally
connected to the arms about an upper pivot axis and a
lower pivot axis spaced from and parallel to the upper
pivot axis. The implement portion includes a coupling
structure for engaging the loader portion. The loader
portion includes a crossmember having a longitudinal
axis parallel to the upper and lower pivot axes. The
loader portion further includes a coupling member
mounted on the crossmember for engaging the coupling
structure on the implement portion such that the
majority of the weight of the implement portion is
transferred to the crossmember. The loader portion
further includes an upper arm pivot structure fixed to
the crossmember for pivotally connecting the upper
arm(s) to the loader portion and lower arm pivot
structure fixed to the crossmember for pivotally
connecting the lower arms to the loader portion. The
longitudinal axis of the crossmember is vertically
located in a range approximately between one third and
two thirds of the distance between the upper and lower
pivot axes.
The coupling member of the preferred coupler has
hook-engaging surfaces which are horizontally located in
a range within the central two-fourths of the width of
the coupler.
The crossmember of the preferred coupler is the
sole member on the loader portion spanning the distance
30 - between the points where the lower loader arms are
connected.
~The preferred coupler further includes locking
devices for locking the implement portion to the loader
portion.
Other objects and advantages and a fuller under-
; standing of the invention will be had from the following
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detailed description of a preferred embodiment and the
accompanying drawings.
Brief Description of the Drawings
Figure 1 is a perspective view of the quick coupler
in an uncoupled state;
Figure 2 is a side elevational view of a prior art
coupler (below) and the coupler of the present invention
(above);
lo Figure 3 is a side elevational view of the quick
coupler with an implement shown in dashed lines;
Figure 4 is a rear elevational view of the loader
portion of the quick coupler;
Figure 5 is a side elevational view seen approx-
imately from the plane indicated by the line 5-5 of
Figure 4;
Figure 6 is a cross-sectional view seen approx-
imately from the plane 6-6 of Figure 4;
Figure 7 is a cross-sectional view seen approx-
imately from the plane indicated by the line 7-7 of
Figure 4;
Figure ~ is a side elevational view of the quick
coupler shown fully coupled to an implement;
Figure 9 is a rear elevational view seen approx-
imately from the plane indicated by the line 9-9 of
Figure 8:
Figure 10 is a rear e~evational view of the
implement portion of the quick coupler;
Figure 11 is a side elevational view seen approxi-
30 _ mately from the plane indicated by the line ll-ll of
Figure 10;
Figure 12 is a side elevational view of a second
embodiment of the loader portion of the coupler of the
present invention;
Figure 13 is a rear elevational view o~ the loader
portion of Figure 12 with the loader arms removed;
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Figure 14 is a side elevational view seen ap-
proximately from the plane indicated by the line 14-1
of Figure 13;
Figure 15 is a cross-sectional view seen ap-
proximately from the plane 15-15 of Figure 13;
Figure 16 is a cross-sectional view seen ap-
proximately from the plane indicated by the line 16-16
of Figure 13;
Figure 17 is a side elevational view of the quick
coupler of the second embodiment shown fully coupled to
an implement; and
Figure 18 is a rear elevational view seen approx-
imately from the plane indicated by the line 18-18 of
Figure 17.
Description of the Preferred Embodiment
Referring now to the drawings, and to Figure l in
particular, a coupler embodying the present invention is
generally designated by reference numeral 10. The
coupler 10 comprises two portions: a loader portion 20
and an implement portion 30. The loader portion 20 is
constructed for attachment to the arms 40, 50, 60 of a
front-end loader (not shown). The implement portion 30
is constructed to be joined to an implement such as a
bucket 70 shown in dashed lines in Figure 1. A pair of
closely spaced hooks 80,90 on the implement portion 30
engage the loader portion 20 to couple the loader
portion 20 to the implement portion 30. The operator of
the front-end loader may readily couple or uncouple the
30 ~ two portions 20, 30 to change implements by maneuvering
the loader portion 20 into engagement with the implement
portion 30.
A front-end loader arm configuration having one
: upper arm 40 and first and second lower arms 50, 60,
respectively, is illustrated in Figures 1-8. As shown
in Figure 3, each arm 40, 50, 60 has a hole at its outer
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end adapted to receive a pin 100 for pivotally connect-
ing the coupler 10 to the arms 40, 50, 60 in a manner
well known in the art. The pin 100 connecting the upper
arm 40 to the coupler 10 defines an upper pivot axis
llo. The pins lO0 connecting the lower arms 50, 60 to
the coupler lo define a lower pivot axis 120 which is
parallel to the upper pivot axis llo.
In the embodiment illustrated in Figures 1-9, the
loader portion 20 comprises a crossmember 140; a
coupling member 150; an upper arm pivot joint 160; first
and second lower arm pivot joints 170, 180, respective-
ly; and a pair of locking mechanisms lso. In general,
the loader portion 20 adapts the ends of the loader arms
40, 50, 60 to fit a specialized cooperating structure,
i.e., the implement portion 30. The loader portion ~o
serv~s to transmit the load of the implement portion 30
to the front-end loader arms 40, 50, 60 when an
implement is attached.
The crossmember 140 forms the main support of the
loader portion 20 and bears the weight of the implement
portion 30. The crossmember 140 is preferably a hollow
cylindrical tube but may be rectangular or otherwise in
cross section. The crossmember 140 includes a first end
200, a second end 210, and a longitudinal axis 220 which
is parallel to the upper and lower pivot axes 110, 120.
The crossmember 140 is the sole structural member
spanning the width o~ the loader portion 20 and is thus
the only structural member resisting torsional and other
stresses acting on the loader portion 20 between the
30 - arms 50,60.
In general, the vertical location of the crossmem-
ber 140 is determined by a compromise between multiple
competing design factors. For example, the vertical
position of the crossmember 140 affects the maximum dump
height of the loader since the upper loader arm 40
inter~eres with the crossmember when the arms 40, 50, 60
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- are fully raised. Thus, while there is some design
flexibility in locating the crossmember 140, in general,
it is desired to locate the crossmember 140 approximate-
ly ~idway between the upper and lower pivot axes llo,
120. The longitudinal axis 220 of the crossmember 140
is preferably vertically located in a range of positions
approximately between one-third and two-thirds of the
distance between the upper and lower pivot axes 110,
120. Figure 4 illustrates the crossmember 140 posi-
tioned within the preferred range.
As best illustrated in Figures 1 and 4, the
coupling member 150 comprises a structure mounted on the
crossmember 140 for receiving the hooks 80,90 of the
implement portion 30. The coupling member 150 is
mounted centrally on the crossmember 140 and extends
upwardly therefrom. The coupling member 150 transfers
substantially all of the weight of the implement portion
30 and any load it may be carrying to the crossmember
140. The coupling member 150 comprises two closely
spaced hook-engaging surfaces 230. The hook-engaging
surfaces 230 are located on opposite sides of a plane
normal to the longitudinal axis 220 bisecting the
loader portion 20. The hooX-engaging surfaces 230 are
symmetrically and centrally located and closely spaced
with respect to each other. Centrally located hook-
engaging sur~aces 230 allow the quick coupler 10 to
mimic a single point pick-up and gain the advantages of
easy coupling inherent in single point pick-up systems.
The quick coupler 10 of the present invention further
30 ~ gains the added strength of two load-bearing hooks 80,
90 and two cooperating hook-engaging surfaces 230.
Preferably, the hook-engaging surfaces 230 are horizon-
- tally located approximately in a range withln the
middle two-Pourths o~ the distance between the lower
loader arms 50, 60. Figure 3 illustrates a horizontal
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location of the hook-engaging surfaces 230 within the
preferred range.
As seen in Figure 4, the coupling member l5o of the
preferred and illustrated coupler lo comprises a T-
shaped structure having two vertical parallel plate
members 240, 250, each welded or otherwise secured at
one end to the mid-section of the crossmember 140 and,
at the opposite end, to a hook-receiving member 260
forming the hook-engaging surfaces 230. The vertical
lo plate msmbers 240, 250 determine the position of the
hook-receiving member 260 and transmit the implement's
load on the hook-receiving member 260 to the crossmember
140. The hook-receiving member 260 is preferably formed
by a cylindrical member fitted into holes formed in the
vertical plate members 240, 250 such that its lon-
gitudinal axis 270 is parallel to and spaced from the
longitudinal axis of the crossmember 140.
The hooks 80, 90 and the cooperating hook-engaging
surfaces 230 are formed to be self-aligning. Tapered
shoulders 280 are formed at the juncture between the
hook-receiving member 260 and the vertical plate members
240, 250 to laterally guide the hooks 80, 90 into
centered engagement with the hook-engaging surfaces 230.
In addition, the round cross sectional shape of the
hook-receiving member 260 in cooperation with the
sloping entrance ways 290 of the hooks 80, 90 serves to
align the seating of the hooks 80, 90 on the hook-
receiving member 260.
As illustrated in Figures 1 and 4, the upper arm
pivot joint 160 is located above the crossmember 140 for
pivotally connecting the upper loader arm 40 to the
loader portion 20. The upper arm 40 pivot joint
includes a plurality of openings 300 aligned with the
upper pivot axis 110, each adapted to receive a portion
of one of the pins 100 for pivotally connecting the
upper arm 40 to the coupler 10. As illustrated in
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Figures 1, 7 and 8, the upper arm pivot joint 160 is
formed in the vertical plate members 240, 250 of the
coupling member 150. One of the openings 300 is formed
in each vertical plate member for receiving one of the
pins 100 which bridges the vertical plate members 240,
250. The upper arm 40 is rotatably coupled between the
vertical plate members 240, 25n about the pin 100.
As illustrated in Figures l and 3, the lower arm
pivot joints 170, 180 are formed by a pair of inner
vertical plates 310, 320 and a pair of outer vertical
plates 330, 340. A first inner vertical plate 310 and a
first outer vertical plate 330 are located proximate the
first end 200 of the crossmember 140 in parallel spaced
relation. In mirror image fashion, a second inner
vertical plate 320 and a second outer vertical plate 340
are located proximate the second end 210 of the
crossmember 140 in a spaced, parallel relationship.
Each of the inner and outer vertical plates 310, 320,
330, 340 has openings 350 aligned with the lower pivot
axis 120. Each opening 350 is adapted to receive a
portion of one of the pins 100 which bridge the inner
and outer vertical plates. The inner and outer vertical
plates are spaced apart sufficiently to permit the outer
ends of the lower arms 50,60 to fit therebetween when
the coupler 10 is connected to the arms 40, 50, 60.
Upper spacers 360 and lower spacers 370 are welded or
otherwise secured between the inner vertical plates 310,
320 and outer vertical plates 330, 340 for holding the
plates together and for setting the spacing therebet-
30 _ ween.
The locking mechanisms 190 include a pair of
extendable and retractable locking pins 380 as shown in
Pigure 4. When extended, the locking pins 380 fit
within apertures 390 (Figure 3) located on the implement
portion 30 to lock the implement portion 30 in place.
The locking pins 380 do not bear the weight of the load
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and are thus easily movable between extended and
retracted positions. In the preferred and illustrated
embodiment, the longitudinal axes of the extendable
locking pins 380 are in alignment with the lower pivot
axis 120 for manufacturing efficiency.
The locking pins 380 may be extended and retracted
manually, hydraulically, pneumatically or electrically.
In the illustrated embodiment, a solenoid 400 is
connected to each locking pin 380 and is operable to
lo retract or extend the locking pins 380 in response to a
signal by the operator from the seat of the front-end
loader.
As best illustrated in Figures 10 and 11, the
implement portion 30 comprises an upper part 410 and a
lower part 420. Both upper and lower parts 410, 420 are
welded or otherwise secured to the various implements to
be used. The upper part 410 comprises the two closely
spaced hooks 80, 90. Each hook includes a downwardly
extending leg 424. The hooks 80, 90 are centrally
located to align with the hook-engaging surfaces 230 on
the loader portion 20.
The lower part 420 includes a pair of extensions
430 having apertures 390 therein. The extensions 430
are constructed and arranged such that the apertures 390
are aligned with the locking pins 380 when the loader
portion 20 and implement portion 30 are fully coupled.
The lower part 420 further includes a pair of laterally
spaced abutments 440 which engage the lower spacers 370
for transmitting forces between the implement portion 30
30 - and the loader portion.
The arrangement of the crossmember 140 and the
inner and outer plates 310, 320, 330, 340 permits the
coupler 10 to fit between the loader arms 40, 50, 60
without extending the payload center of gravity 442
further from the front-end loader than it would be
without a coupler. Figure 2 illustrates a bucket 70
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attached directly to the arms of a front end loader in
the lower view. The upper view shows the coupler 10
coupling the bucket 70 to the loader arms 60. In both
views of Figure 2, the distance D from the payload
center of gravity 442 to the lower pivot axis is the
same.
In a second embodiment illustrated in Figures 12-
18, the loader portion, designated generally by
reference numeral 450, is constructed to fit a front-end
loader having an arm configuration comprising two upper
arms 460, 470 and two lower arms 50, 60. The loader
portion 450 of the second embodiment differs from the
loader portion 20 of Figures 1-9 in that two upper pivot
joints 480, 490 are provided for connecting two upper
arms 460, 470 to the loader portion rather than one.
The loader portion 450 of Figures 12-18 is otherwise the
same as that discussed above with reference to Figures
1-9. Parts which are unchanged between the two
embodiments have the same reference characters.
Referring in particular to Figure 18, a loader
portion 450 is shown attached to a pair of upper loader
arms 460, 470 and a pair of lower loader arms 50, 60.
The loader portion 450 is pivotal with respect to the
upper arms 460,470 about an upper pivot axis 500 and
with respect to the lower arms 50, 60 about a lower
pivot axis 120 which is parallel to and spaced from the
upper pivot axis 500.
As in the embodiment of Figures 1-9, lower arm
pivot joints 170, 180 illustrated in Figure 18 are
formed bv a pair of inner vertical plates 590, 550 and a
pair of outer vertical plates 560, 570. A first inner
vertical plate 540 and a first outer vertical plate 560
are located proximate the first end 200 of the crossmem-
ber 140 in parallel spaced relation. In mirror image
fashion, a second inner vertical plate 550 and a second
outer vertical plate 570 are located proximate the
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second end 210 of the crossmember 140 in a spaced,
parallel relationship. Each of the inner and outer
vertical plates 540, 550, 560, 570 have openings 350
aligned with the lower pivot axis 120 for supporting
pins 100 rotatably joining the lower arms 50, 60 to the
loader portion 450.
As best illustrated in Figure 18, the vertical
plates 540, 550, 560, 570 extend upwardly above the
crossmember 140 to form the upper pivot joints 480, 490.
Openings 580 are formed in the plates 540, 550, 560, 570
in alignment with the upper pivot axis 500 for receiving
pins 100 which rotatably support the upper arms 460, 470
in the manner of the lower pivot joints 170, 180.
While a single preferred embodiment of the
invention has been illustrated and described in detail,
the present invention is not to be considered limited to
the precise construction disclosed. Various adapta-
tions, modifications and uses of the invention may
occur to t~ose skilled in the art to which the invention
relates and the intention is to cover hereby all such
adaptations, modifications and uses which fall within
the spirit or scope of the appended claims.
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