Note: Descriptions are shown in the official language in which they were submitted.
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GRAPPLE NOUNT
Background of the Invention
1. Field of the Invention
This invention relates to grapples, and m o r e
specifically to apparatus for mounting grapples to the
articulated boom of an excavator.
2. Description of the Prior Art An excavator equipped
with a hydraulically-actuated boom, an arm attached to
the boom, and a thumb and bucket attached to a free end
of the arm, is commonly used in road clearing operations,
particularly in forested regions. The bucket is used for
digging up soil and removing debris from the surface of
the ground. After trees have been felled as part of a
road clearing process, the logs may be grasped and
removed by the thumb; unfortunately, the logs are often
broken or crushed in the process. A grapple mounted on
the end of the arm provides a superior means for grasping
and lifting logs. In the prior art, however, it has been
necessary to remove both the thumb and the bucket from
the end of the arm in order to mount a grapple, which is
a time-consuming procedure. It is desirable, therefore,
to provide apparatus for attaching a grapple on the end
of the arm of an excavator without the necessity of
having to remove either the thumb or the bucket. When an
excavator is equipped with such an apparatus, including
a grapple mount and a hydraulic drive system suitably
modified to actuate a grapple attached to the grapple
mount, it is possible to continuously and rapidly
alternate between removal of logs and stumps using a
grapple and removal of soil and debris using a bucket.
~UMMARY OF THE INVENTION
The present invention overcomes the problems
outlined above and provides apparatus for attaching a
grapple to a hydraulically actuated articulated boom of
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an excavator equipped with both a thumb and a bucket,
without requiring the removal of either the thumb or the
bucket. The apparatus of the invention includes a
detachable grapple mount for attaching a grapple to an
arm of the excavator. A thumb pin is provided for
attaching one end of the grapple mount to the thumb, and
a drop link is provided at an opposite end of the grapple
mount for suspending a grapple. The apparatus further
includes a first diverter valve for diverting hydraulic
fluid alternately to the thumb or to the grapple. A
second diverter valve, connected by flexible conduit to
the first diverter valve, is also provided for diverting
hydraulic fluid alternately through a path that actuates
opening and closing movements of the grapple or through
a path that actuates rotational movements of the grapple.
In a preferred embodiment wherein the diverter valves are
electrically actuated, an electric power source is
provided, and electric control switches are mounted
inside the excavator cab for controlling the diverter
valves.
BRIEF DE8CRIPTION OF THE DRAWING8
FIG. 1 is a frontal perspective view of an
excavator equipped with a bucket, shown in lowered
position, and a thumb, shown in raised position, and with
a grapple mount attached to the thumb;
FIG. 2 is an enlarged side elevational view of an
excavator showing the bucket in raised position and a
grapple suspended by a drop link from a grapple mount
attached to the thumb;
FIG. 3 is a left-frontal perspective view of the
grapple mount;
FIG. 4 is an underside plan view of the thumb and
grapple mount, with the grapple removed, as viewed in a
direction normal to the longitudinal axis L of the thumb,
showing an outline of the flared portion of the cowl of
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the mount by dashed lines;
FIG. 5 is a right-frontal perspective view of the
thumb, removed from the excavator arm, with the grapple
mount attached;
FIG. 6 is a schematic diagram of the hydraulic system
of the excavator as modified by the invention;
FIG. 7 is a schematic wiring diagram for the
electrically actuated first and second diverter valves.
The terms "front" and "forward" as used herein generally
refer to the right portions of the excavator as
illustrated in FIG. 1, except that in reference to the
attachments to the boom, those terms shall refer to the
direction defined by the sequence progressing from the
boom through the arm, thumb, and grapple mount, in that
order; similarly, the terms "rear" and "rearward" refer
to the left portions of the excavator so illustrated,
except that in reference to the attachments to the boom,
those terms shall refer to the direction defined by the
reverse sequence.
DESCRIPTION OF THB PREFERRED ENBODIMENT
Referring now to the drawings, a grapple mount
according to the present invention is illustrated in
FIG. 1 and shown generally by reference numeral 10.
Grapple mount 10 is shown mounted on an excavator 20,
e.g., a model 790D-LC manufactured by the John Deere
Company of Moline, Illinois, which includes a body 22
mounted on treads 24. A cab 27 is mounted on a front
portion of the body 22. A boom 25 is carried by the
body 22, from which it extends forwardly and with which
it swings about a vertical axis with respect to the
treads 24 in response to activation of control levers
by an operator in the cab 27. A parallel pair of
hydraulic boom cylinders 28, 28', which include pistons
(not shown) and piston rods 30, 30', are each connected
at one end to a front portion of the body 22 and at an
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opposite end to a central portion of the boom 26. A
forward portion of the boom 34 is fitted with a clevis
36 to which an arm 32 is pivotally mounted by arm pin
38 for rotation about a horizontal axis. An arm
cylinder 40 comprising a piston (not shown) and a
piston rod 42 is attached to an upper surface 44 of a
central portion 26 of the boom 25 with the piston rod
42 thereof pivotally connected by drive pin 52 to a
rear clevis 51 of the arm 32 that extends rearward from
pin 38. A forward portion 50 of the arm 32 is fitted
with a transverse pin boss (not shown) for pivotally
mounting by bucket pin 62 both a bucket 60 and a thumb
70 for rotation about a common horizontal axis. That
is, by removing bucket pin 62 either the bucket 60 or
the thumb 70, or both, may be removed from the arm 32.
A bucket cylinder 73 comprising a piston (not
shown) and a bucket cylinder rod 69 is pivotally
attached by bucket drive pin 76 to a bucket drive
clevis 74 mounted on an upper surface 58 of the arm 32.
A parallel pair of arm linkage bars 80, 80' each have
one end pivotally connected to a front portion 50 of
arm 32 and an opposite end connected to the bucket
cylinder rod 69 by linkage pin 82. A parallel pair of
bucket linkage bars 84, 84' each have one end pivotally
attached to a bucket control clevis 86 by bucket
control clevis pin 88 and an opposite end attached to
linkage pin 82.
Referring now to FIG 2, the thumb 70 extends
longitudinally from the bucket pin 62 along axis L. A
rear portion 74 of the thumb 70 is provided with a pair
of parallel, spaced-apart apertured ears 72, 72' for
transverse insertion of the bucket mount pin 62, as may
be seen in underside plan view in FIG. 4. The ears 72,
72' extend rearwardly from the rear 81 of the thumb 70.
The thumb 70 further comprises a body portion 78 which,
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as viewed from the underside thereof, is defined by a
parallel pair of longitudinal walls 93, 93', a
transverse wall 95 extending between the longitudinal
walls 93, 93' at a forward portion 76 of the thumb 70,
and extends to the body rear 81. The forward portion
76 of the thumb 70 further comprises a parallel array
of four spaced-apart, substantially identical fingers
71, which fingers are reinforced by gussets 101
extending forwardly from the transverse wall 95. Each
of the fingers 71 is an elongated strip formed from
metal plate and having a downwardly-curved tooth end
71T for tearing into soil and debris, as may best be
seen in FIG. 5.
Referring now to FIG. 3, my grapple mount 10
comprises a cowl 89, a pair of parallel walls 92, 92'
that depend perpendicularly from the cowl 89, and a
pair of apertured ears 94, 94' that are contiguous with
walls 92, 92', respectively, and project forwardly and
downwardly therefrom. Referring to FIGS. 3 - 5, it may
be seen that the cowl 89 is a metal plate convexly and
progressively bent from rear to front at spaced-apart,
transverse creases 96, 96', 96", thereby defining a
base plate 190, a rear plate 192, a central plate 194,
and a forward plate 196, whereby the cowl 89, when in
use, is adapted to closely overlie the body 78 and
fingers 71 of the thumb 70. The cowl 89 is outwardly
flared from front to rear, that is, to the rearmost
crease 96, such that the width of the baseplate 190 of
the cowl 89 is substantially equal to the width of the
thumb 70. The front margin 98 of the forward plate 196
of the cowl 89 is substantially equal to the distance
between the two inner fingers 71 of the thumb 70.
The walls 92, 92', which are identically-shaped,
are metal plates having straight front margins 100,
100', normal to the front margin 98 of the forward
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plate 196, and a lower margin 102 that is upwardly
oblique from front to rear and terminating at crease
96, whereby each wall is substantially triangular in
plan form. An apertured ear 106, 106' projects
rearwardly from a central portion of each wall 92, 92'.
The regions of intersection of the lower margin 102,
102' with the ears 106, 106', therefore, form notches N
adapted for receiving the gussets 101 adjacent to the
inner two fingers 71I of the thumb 70. In order to
connect the grapple mount 10 to the thumb 70, however,
it is first necessary to create a transverse bore
through the two interior fingers 7lI; this permits
insertion of pins 114 through said bores and through
apertured ears 106, 106' to attach the grapple mount 10
to a forward portion of the thumb 70. The base plate
190 includes a plurality of apertures 112 for insertion
of bolts (not shown) by which to connect the grapple
mount 10 to the body 78 of the thumb 70. Attached to
the forward plate 196 is a hose stay 110 in the form of
an inverted U.
The excavator of the kind described comes equipped
with hydraulic line controls in the cab 27: a first
lever 121 controls up and down movements of the boom 25
and left-and-right swings of the boom; a second lever
controls arm and bucket functions, and a thumb control
valve 143 controls the thumb 70. A button trigger 124
on the first lever 121 reverses hydraulic flow. Right
and left pedals control forward, reverse and
counterrotation movements. It is necessary to modify
the hydraulic system of the excavator 20 in order to
provide hydraulic actuation to a grapple 35 that is
installed on the excavator 20 by means of the grapple
mount 10. The apparatus of the present invention
includes components that modify the hydraulic system of
the excavator to provide hydraulic actuation for
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alternately opening and closing movements of the
grapple and rotation of the grapple 35. As shown
diagrammatically in FIG. 6, the modified hydraulic
system includes a hydraulic pump 122 that provides
hydraulic fluid under pressure to the thumb 70 through
hydraulic line 130 in a flow direction determined by
the status of the button flow reverser 124, and a first
control lever 121 that controls up and down and swing
movements of the boom 26. The excavator 20 also comes
equipped with another hydraulic line 131 to provide
hydraulic fluid under pressure for opening and closing
the bucket 60.
According to the present invention, a first
diverter valve 126, however, is inserted in series with
hydraulic line 137 for diverting hydraulic fluid, under
control of operator selectable settings of a first
electrical switch (not shown) mounted in the cab 27,
from the thumb 70, where it otherwise would actuate the
thumb open/close cylinder 90 to cause the thumb 70 to
open and close, through hydraulic line 137' to a second
diverter valve 132. The second diverter valve 132,
under control of operator selectable settings of a
second electrical switch (not shown) mounted in the
cab, diverts the fluid either to hydraulic line 140 to
actuate opening and closing movements of the grapple 35
by means of cylinder 170 or through line 140' to
actuate grapple hydraulic motor 172 for rotational
movements of the grapple 35. The first and second
diverter valves are two-position, electrically-actuated
hydraulic valves, such as Valvoil DF 20/6A 18E,
Ouebec, Canada. Referring to FIG. 7, a 24-volt
electric battery 150 wired in series with a first,
two-position electric switch 152 energizes the first
diverter valve 126 to switch alternately between
permitting fluid flow through line 137 and line 137'.
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Similarly, the battery 150 wired in series with a
second, two-position electric switch 154 energizes the
second diverter valve 132 to switch alternatively
between permitting hydraulic fluid to flow through line
140 and line 140'. The first and second electric
switches 152, 154 are preferably mounted in the cab 24
on the first and second levers, respectively.
For use in clearing roads in forested areas, the
bucket 60 and the thumb 70 are both mounted on the arm
32 by means of pin 62. When it is desired to use a
grapple to remove logs and stumps, the ears 106, 106'
of the grapple mount 10 are placed between the interior
teeth 71I of the thumb 70 and secured in position by
pins 114, and the cowl 89 is bolted to the thumb 70. A
drop link 160 is attached to ears 94, 94' by means of a
grapple pin 162 to which a grapple 35 is attached,
thereby suspending the grapple 35 from the thumb 70.
With the first switch 152 in a first position, the
first diverter valve 126 routes hydraulic fluid to the
thumb 70 so that the operator may then manipulate the
first and second levers and the button flow reverser in
the cab to position the grapple by vertical and
horizontal movements of the boom, as well as by
vertical movements of the thumb 70. To open the
grapple 35 preparatory to grasping a log, the first
switch 152 is flipped to a second position, whereby the
first diverter valve 126 routes hydraulic fluid to the
second diverter valve 132, and the second switch 154 is
placed in a first position whereby the second diverter
valve 132 routes hydraulic fluid to the grapple
open/close cylinder 170. To close the grapple 35
around the log, the button flow reverser 124 is
depressed. If it is desired to rotate the grapple 35,
however, the second switch 154 is placed in a second
position thereby causing the second diverter valve 132
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to route hydraulic fluid to the grapple rotate motor
172.
Various details of the invention may be changed
without departing from its scope. For example, the
first and second diverter valves could be inserted into
the hydraulic line 131 for the bucket instead of in the
hydraulic line for the thumb 130. Furthermore, the
description of the preferred embodiment according to
the present invention is provided for the purpose of
illustration only and not for the purpose of limitation
-- the invention being defined by the claims.
