Note: Descriptions are shown in the official language in which they were submitted.
CA 02383336 2002-05-16
TITLE OF THE INVENTION: THUMB FOR SCOOPING TOE
FIELD OF THE INVENTION
The present invention relates to mechanical scooping tool arms such as
hydraulic shovels, hydraulic rakes and the like, and more particularly to a
thumb for such a
scooping tool arm.
BACKGROUND OF THE INVENTION
Articulated mechanical scooping tool arms are often operatively mounted to
1.0 a vehicle to allow heavy or large materials to be handled. Such material
handling apparatuses
include hydraulic shovels, hydraulic rakes, and the like. In all these cases,
a scooping tool,
such as a bucket or a rake, is provided at the outer free end portion of an
articulated boom, and
is remotely controlled from the vehicle cab through the instrumentality of
hydraulic cylinders.
The scooping tool can be used to accomplish a number of different operations,
one of them
1.5 being to scoop up materials to transport them. For example, a bucket can
be used to dig a hole
in the ground, or to scoop up and lift a heavy container to carry it to a
desired destination.
In the cases of vehicles equipped with a scooping tool in the form of a
hydraulic
shovel, it is known to operatively mount a hydraulically controlled thumb on
the tool arm of
the vehicle in pivotal facing register with the bucket of the hydraulic
shovel, the thumb
20 pivotally co-operating with the bucket of the hydraulic shovel to allow
objects to be grasped
between the bucket and the thumb. or to be pushed by the thumb into the
bucket. However,
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the known thumbs are cumbersome when they are positioned in a stored condition
away from
the bucket, and their shapes are not adapted for efficiently handling
materials without
damaging these materials.
SUMMARY OF THE INVENTION
The present invention relates to a thumb to be mounted for relative movement
on a hydraulic tool arm equipped with a pivotable scooping tool for selective
co-operation
between the scooping tool and said thumb, said thumb comprising a pair of
generally parallel
transversely spaced arcuate U-shaped lateral forks, said forks having inner
ends transversely
LO interconnected by an integral transverse coupling member having for
operative coupling of said
thumb to the tool arm for relative movement thereabout, and outer ends
opposite said inner
end, said arcuate forks defining a significantly short radius of curvature
about a common axis
relative to the distance between said inner and outer ends.
In one embodiment, the thumb further comprises a transverse plate integrally
1.5 linking said forks at said outer ends thereof.
In one embodiment, said coupling member is a pivotal coupling member and
defines a pivotal axis.
In one embodiment, said forks define a concave inner surface and a ratio L1:L2
approximately equal to 3:1 is defined on said thumb, where L i is equal to the
length between
20 said pivotal axis and said forks outer ends, and where L2 is equal to the
length between (a) a
line drawn between said pivotal axis and said forks outer ends, and (b) the
most distant point
CA 02383336 2002-05-16
between said concave inner surface of said forks and said line.
In one embodiment, said forks are defined along a major part of their length
starting at said outer ends, by a single radius of curvature R1, and a ratio
L1:R1 approximately
equal to 2:1 is defined on said thumb, where L 1 is equal to the length
between said pivotal axis
and said forks outer ends.
The present invention also relates to a thumb assembly for use on a tool arm
equipped with a scooping tool, comprising a thumb for selective co-operation
with the
scooping tool, said thumb comprising a pair of generally parallel U-shaped
lateral forks
defining an opening therebetween for engagement of the tool arm between said
forks, said
:L 0 forks having inner ends for pivotable attachment to the tool arm and
outer ends opposite said
inner ends, said forks being significantly curved about a common axis for
providing a hollow
opening between the scooping tool and said thumb when said thumb forks outer
ends engage
the scooping tool and for allowing a significant portion of said thumb to be
positioned beyond
a surface of the tool arm which is in pivotal facing register with a scooping
side of the
scooping tool when said thumb is pivoted against the tool arm, said thumb
assembly further
comprising an actuator operatively attached to said thumb for allowing pivotal
displacement
of said thumb relative to the scooping tool.
The invention also relates to a thumb and scooping tool assembly for operative
attachment to a tool arm, comprising:
a) a thumb, said thumb comprising a pair of generally parallel U-shaped
lateral forks
defining an opening therebetween for engagement of the tool arm between said
forks, said
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forks having inner ends for attachment to the tool arm for relative movement
thereabout, and
outer ends opposite said inner ends, said forks being significantly curved
about a common axis;
b) a scooping tool selectively co-operating with said thumb and comprising an
inner end
for pivotable attachment to the tool arm, an outer end opposite said inner
end, and a scooping
side in pivotal facing register with said thumb for grasping objects between
said thumb and
said scooping tool scooping side;
c) mounting means, for mounting said thumb forks inner ends and said cooping
tool to
the tool arm for relative movement thereabout;
d) a first actuator operatively attached to said thumb for selective motion of
said thumb
relative to said scooping tool and to the tool arm; and
e) a second actuator operatively attached to said scooping tool for selective
motion of said
scooping tool relative to said thumb and to the tool arm.
The invention further relates to a tool arm assembly comprising an elongated
tool arm having an outer free end equipped with a scooping tool and a thumb,
said thumb
1.5 comprising a pair of generally parallel U-shaped lateral forks defining an
opening
therebetween, said forks having inner ends, a pivot member pivotably attaching
said forks
inner ends to the tool arm outer free end for pivotal movement of said thumb
about a pivotal
axis, and outer ends opposite said inner ends, said forks being significantly
curved about a
common axis, said scooping tool selectively co-operating with said thumb and
comprising an
inner end pivotably attached to said pivot member for pivotal motion relative
to said tool arm
outer free end, an outer end opposite said inner end, and a scooping side in
pivotal facing
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register with said thumb for grasping objects between said thumb and said
scooping tool
scooping side, said tool arm assembly further comprising a first power
actuator operatively
attached to said tool arm and to said thumb for selectively pivoting said
thumb relative to said
scooping tool and to said tool arm, said tool arm assembly further comprising
a second power
actuator operatively attached to said tool arm and to said scooping tool for
selectively pivoting
said scooping tool relative to said thumb and to said tool arm;
wherein said pivot member enables said thumb and said scooping tool to be
independently
pivotable relative to one another and to said tool arm about parallel axes.
and wherein said
thumb is pivotable between a first limit position in which said forks outer
end engages said
scooping tool scooping side, and a second limit position in which said thumb
is pivoted away
from said scooping tool scooping side and said tool arm is embedded in said
opening between
said thumb forks, with a transverse hollow opening being defined between said
forks and said
scooping tool scooping side in said first limit position of said forks for
transverse,
uncompressed engagement of objects carried therein, and with a significant
portion of said
1.5 thumb extending beyond a surface of said tool arm that is in pivotal
facing register with said
scooping tool scooping side when said thumb is in said second limit position.
In one embodiment, said thumb and said scooping tool both pivot about said
pivotal axis.
In one embodiment, said thumb comprises a transverse plate integrally linking
said forks at said outer ends thereof, with said transverse plate being
positioned, in all positions
of said thumb, between said scooping tool scooping side and said surface of
said tool arm that
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is in pivotal facing register with said scooping tool scooping side.
The invention further relates to a vehicle comprising:
a frame movable over ground;
a boom pivotably attached to said frame;
- an elongated tool arm having an inner end pivotally attached to said boom
and an outer
free end opposite said inner end and equipped with a scooping tool and a
thumb, said thumb
comprising a pair of generally parallel U-shaped lateral forks defining an
opening
therebetween, said forks having an inner end pivotably attached to the tool
arm outer free end
and an outer end opposite said inner end, said forks being significantly
curved about a common
axis, said scooping tool selectively co-operating with said thumb and
comprising an inner end
pivotably attached to the tool arm outer free end, an outer end opposite said
inner end, and a
scooping side in pivotal facing register with said thumb for grasping objects
between said
thumb and said scooping tool scooping side;
a first actuator operatively attached to said tool arm and to said thumb for
selectively
1.5 pivoting said thumb relative to said scooping tool and to said tool arm;
a second actuator operatively attached to said tool arm and to said scooping
tool for
selectively pivoting said scooping tool relative to said thumb and to said
tool arm;
a third actuator operatively attached to said boom and to said tool arm, for
selectively
pivoting said tool arm relative to said boom;
210 - a fourth actuator operatively attached to said vehicle frame and to said
boom, for
selectively pivoting said boom relative to said vehicle:
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wherein said thumb and said scooping tool are independently pivotable about
parallel axes, and
wherein said thumb is pivotable between a first limit position in which said
forks outer end
engages said scooping tool scooping side, and a second limit position in which
said thumb is
pivoted away from said scooping tool scooping side and said tool arm is
embedded in said
opening between said thumb forks, with a transverse hollow opening being
defined between
said forks and said scooping tool scooping side in said first limit position
of said forks for
transverse, uncompressed engagement of objects carried therein, and with a
significant portion
of said thumb extending beyond a surface of said tool arm that is in pivotal
facing register with
said scooping tool scooping side when said thumb is in said second limit
position.
In one embodiment, said scooping tool is a bucket.
In one embodiment, said scooping tool is a rake.
DESCRIPTION OF THE DRAWINGS
In the annexed drawings:
1.5 Figure 1 is a side elevation of a vehicle comprising a tool arm equipped
with
a thumb according to the present invention;
Figures 2 and 3 are enlarged perspective views of the tool arm equipped with
the thumb of the invention, respectively showing the thumb in a first position
in which it is
pivoted towards the bucket of the tool arm, and in a second position in which
it is pivoted away
from the bucket, engaging the tool arm in a stored position;
Figure 4 is a side elevation of the tool arm equipped with the thumb of the
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invention in its stored position of figure 3;
Figures 5 and 6 are respectively a side elevation and a rear elevation of the
thumb of the invention. at an enlarged scale; and
Figure 7 is a perspective view of the tool arm equipped with a thumb according
to the invention. with the thumb and the bucket of the tool arm co-operating
to grasp and
handle a cylindrical container.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Figure 1 shows a material handling vehicle 10 comprising a cab 12 rotatably
1.0 mounted, by means of a turntable 14. to a frame (concealed in figure 1)
carried over ground
by a pair of tracks 16. Cab 12 can thus be moved over ground and can rotate
about a vertical
axis (if vehicle 10 is located over horizontal ground), as known in the art.
An elongated boom 18 is pivotably attached to cab 12, with a boom cylinder
20 controlling the pivotal displacement of boom 18. Boom cylinder 20 is
attached at its first
end to cab 12 and at its second end to boom 18. An elongated tool arm 22 is
pivotally attached
to boom 18 at 23, at the end of boom 18 opposite cab 12, with an arm cylinder
24 controlling
the pivotal displacement of tool arm 22. Arm cylinder is attached at its first
end to cab 12, and
at its second end to boom 18.
Figures 1-4 and 7 show that tool arm 22 carries a tool in the form of a bucket
26 which is pivotally attached to tool arm 22 by means of a hinge pin 28 which
transversely
extends through the outer free end of tool arm 22. Bucket 26 is controlled in
its pivotal
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displacement by means of a bucket cylinder 30. Bucket cylinder 30 is attached
at its first end
to tool arm 22, and at its second end to bucket 26. A pair of bucket pivot
rods 32 is pivotally
attached at its first end to tool arm 22 by means of a pivot pin 34, and at
its second end to an
articulation joint 36 provided on at the outer end of the piston of bucket
cylinder 30. A pair
of bucket link rods 37 link articulation joint 36 to bucket 26, with bucket
link rods 37 being
pivotally attached to articulation 36 and pivotally attached to bucket 26
spacedly from hinge
pin 28.
Figures 1-4 show that, according to the present invention, vehicle 10 is
equipped with a thumb assembly 38. Thumb assembly 38 comprises a thumb 40
pivotally
attached by means of hinge pin 28 to the outer free end of tool arm 22. Thus,
hinge pin 28 is
used to pivotally attach both thumb 32 and bucket 26 to the outer free end of
tool arm 22,
although both are independently pivotable relative to tool arm 22. Thumb
assembly 38 further
comprises a thumb cylinder 42, attached to tool arm 22 at its first end and to
thumb 40 at its
second end, with thumb cylinder 42 controlling the pivotal displacement of
thumb 40. A pair
of thumb pivot rods 44 are pivotally attached to pivot pin 34 at their first
end, and to an
articulation joint 45 at their second end, with articulation joint 45 being in
turn linked to thumb
40 by means of an arcuate thumb link rod 47.
As shown in figures 1-7, thumb 40 comprises a generally annular main body
having a pair of generally parallel curved forks 46, 48 linked at their inner
end, near hinge pin
28 although spacedly therefrom, by an inner transverse hollow cylindrical
pivot sleeve 50 and
at their outer free end, opposite hinge pin 28, by an outer transverse plate
52. Inner transverse
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sleeve 50 has a notch 54, with thumb link rod 47 being attached through notch
54 to a pivot
pin (concealed by sleeve 50 in the drawings) located inside sleeve 50. Outer
transverse plate
52 has a semi-circular notch 56 for free engagement therein of thumb cylinder
42 in some
positions of thumb 40.
It can be seen that the lateral forks 46, 48 have larger base portions 46a,
48a,
opposite outer transverse plate 52, where sockets 46b, 48b are provided for
engagement there
of hinge pin 28. Transverse sleeve 50 links the forks base portions 46a, 48a.
Also, U-shaped
forks 46, 48 are curved about a common axis.
Boom cylinder 20, tool arm cylinder 24, bucket cylinder 30 and thumb cylinder
1.0 42 can all be controlled remotely from cab 12.
Thus, upon the piston rod of thumb cylinder 42 being activated, thumb link rod
47 will act on the pivot pin located inside thumb inner transverse sleeve 50,
to pivotally rotate
thumb 40 between a first fully opened inoperative limit position shown in
figures 3 and 4
where transverse plate 52 is adjacent to and almost abuts against cylinder 42
and tool arm 22,
1.5 through an intermediate jaw grasping position shown in figures 1 and 2,
and into a second
closed load-securing limit position shown in figure 7.
In its opened limit position, thumb 40 extends generally along tool arm 22.
More specifically, tool arm 22 becomes embedded into the opening 58 (figure 6)
formed
between forks 46, 48, transverse sleeve 50 and transverse end plate 52, with
forks 46, 48, due
20 to their curved shape, extending on each side of tool arm 22. The only
portion of thumb 40
which remains between tool arm 22 and the scooping side 26a of bucket 26, is
the transverse
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end plate 52 and the end tips of forks 46, 48 which hold transverse end plate
52. In this
position of thumb 40, thumb cylinder 42 extends through the transverse end
plate notch 56.
This opened limit position of thumb 40 is very advantageous in that thumb is
not cumbersome,
since it is stored out of the way of bucket 26, which can consequently be used
independently
of thumb 40. In this opened position of thumb 40, a significant portion of
thumb 40 extends
beyond the surface 22a of tool arm 22 which is in pivotal facing register with
the scooping side
26a of pivotable bucket 26 (figure 4). Thus, bucket 26 may have a full range
of pivotal
displacement even though tool arm 22 is equipped with thumb 40, since the
latter is positioned
out of the way.
In its closed condition, thumb 40 can co-operate with bucket 26 to handle
materials, for example a cylindrical container C as shown in figure 7. The
thumb transverse
endplate 52 can indeed abut against the outer free tip 60 of bucket 26, to
form a hollow
transverse opening between bucket 26 and the curved forks 46, 48. Due to this
curved shape
of forks 46, 48, objects or materials such as container C can be grasped in
the hollow opening
formed by forks 46, 48 and bucket 26, without being compressed. This is
advantageous, since
it prevents such materials from being damaged.
Thus, the U-shaped forks 46, 48 have a significant curve that allows them: (1)
to be stored on each side of tool arm 22 in the inoperative condition of thumb
40, out of the
way of the angular travel path of the bucket 26; and (2) to co-operate with
bucket 26 in its
?_ 0 operative closed position to grasp and handle materials while providing a
hollow opening
between the thumb forks 46, 48 and the bucket 26, so as to enable many
articles being grasped
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and handled to project through and being this hollow opening without being
compressed or
damaged.
Figure 5 shows that the thumb forks 46. 48 have significantly short radii of
curvature. Typically, these radii of curvature will be shorter than that of
bucket 26. It is
understood that the size of thumb will vary according to the tool it is
intended to be used with,
but the following values, given by way of example, have been found to provide
advantageous
and unexpected results:
RI: 28 inches; R1 is the larger radius of curvature defining most of the
forks' curvature at
the free end thereof;
R2: 13 inches; R2 is the smaller radius of curvature defining the innermost
portion of the
forks;
L I: 60 inches; L 1 is the spacing between the pivotal axis of thumb 40 and
the outer free tip
of forks 46, 48; and
L2: 20 inches; L2 is the spacing between (a) a line linking the pivotal axis
of thumb 40 and
1.5 the outer free tips of forks 46, 48, and (b) the most distant portion of
the inner surface of forks
46, 48 relative to this line and calculated at a right angle relative to this
line.
Thus, it can be seen that the following approximated ratios are defined:
L1:L2 = 3:1
L1:Rl = 2:1
Rl:R2=2:1
It is understood, however, that the above-mentioned dimensions and ratios may
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be modified without departing from the scope of the present invention.
It is understood that the bucket 26 could be replaced with any suitable
hydraulically controlled scooping tool, such as a rake or the like.
Also, the shape of thumb 40 could be modified without departing from the
scope of the present invention. For example, the transverse end plate 52 could
be removed,
although that would structurally weaken thumb 40 unless it was made from a
very resistant
material.
Furthermore, each hydraulic cylinder may be substituted by any suitable
actuator.
Any further modification to the present invention, which does not deviate from
the scope thereof, is considered to be included therein.
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