Note: Descriptions are shown in the official language in which they were submitted.
Title: Apparatus for mounting on a tractor or other vehicle
and providing opposed movement to digging or lifting
implements.
Background of the invention.
l.Field of the Invention
The present invention relates to apparatus suitable for
mounting on a vehicle, which may be a conventional tractor, the
apparatus being capable of providing opposed movement to a pair
of implements mounted on arms of the apparatus. The apparatus
may be used with a variety of implements which may be
interchangeable, and which will usually include digging and
lifting implements.
2.Prior Art
The prior art of digging and transplanting equipment
includes many fairly complicated, expensive, and specialized
machines for performing particular tasks. Many of these
machines require special vehicles which may be integral with
the machine. However, some prior art devices can be attached to
a conventional tractor, for example as described in the
following patents:
U.S.Pat.No.3,193,951, issued July 13,1965 to Beeson;
U.S.Pat.No.3,558,177, issued Jan.26,1971 to Snead;
U.S.Pat.No.3,618,234, issued Nov.9,1971 to Bates;
U.S.Pat.No.4,045,891, issued Sept.6,1977 to Grew; and
U.S.Pat.No 5,217,274, issued Jun.8,1993 to Ilchuk.
The devices described in the above patents are relatively
complex, usually involving several hydraulic cylinders, and are
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also somewhat specialised in their application. The present
invention, by contrast, provides apparatus which is simple and
inexpensive enough to be afforded by an average hobby farmer,
which can be attached to various vehicles including a tractor
having the conventional three-point hitch, or having other
hitches, and which is adaptable to a wide variety of uses in
addition to digging and transplanting small trees and shrubs.
In one of its forms, the apparatus requires only a single
hydraulic cylinder. The apparatus provides opposed movement to
a pair of cooperating implements, which may be spade-type
implements suitable for digging or transplanting, but which may
also be implements suitable for lifting logs or brushwood, or
for moving large stones; such implements are not confined to
use in farming.
Summary of the Invention
In accordance with the present invention, apparatus
suitable for providing opposed movement to a pair of
cooperating implements, comprises;
a frame having (when normally disposed) an upper central
region and two laterally spaced lower regions;
two movable arms, each arm having an inner end pivotally
mounted to the frame at one of said lower regions by a pivot,
the pivots being such as to restrict movement of the arms,
relative to the frame, to mutually inclined pivot planes
oriented relative to the frame to slope downwardly and inwardly
towards each other and to meet at a line of intersection which
is situated below and symmetrically between said pivots, each
arm having an outer end portion capable of carrying one of said
implements, and
power means for moving the arms to bring together
implements carried thereby.
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With the frame stationary and in its normal vertical
position, the implements carried by the arms move in opposed,
downwardly inclined paths preferably inclined at about 45° to
the horizontal. This provides a useful motion for opposed
digging implements which may each have a digging blade
generally aligned with the path of movement, these blades
moving towards each other and meeting along the line of
intersection which will normally be aligned behind the tractor
axis. Suitable blades moved in this manner will dig themselves
into the soil without the need for substantial downwards force
to be applied. The combined vertical and horizontal swinging
motion provided in this invention by the orientation of the arm
pivots is the kind of motion which in prior art devices would
typically require simultaneous operation of two hydraulic
cylinders acting in mutually perpendicular planes.
Another advantage of the kind of movement provided for the
arms of this invention is that they allow digging implements to
start from a wide spacing and to move inwardly and downwardly
towards each other to a final position below the root of a
tree, with little interference with its branches. By contrast,
a typical prior art mechanism, such as that of the above-
mentioned patent to Ilchuk, has rotatable clam-shell type
digging elements mounted on fixed parallel arms extending at
the level of tree branches, and such arms are apt to interfere
with the branches of trees unless the trees are quite small.
In order to limit strain on the arm pivots, supporting
links may be provided connecting the upper central region of
the frame to each arm, each link having pivotal connection with
the frame to allow the arm to be supported by the link over a
range of movement. The link may be fixed to the respective arm
and may be pivoted to the frame by a pivot aligned with the arm
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pivot. Alternatively, the connection between the link and the
arm may include a pivot, preferably having some looseness as
may be necessary to accommodate more complex relative motion.
The links may each comprise part of a lever, the two levers
being connected to opposite ends of a power cylinder for
transmitting movement to the arms. Thus the apparatus may
operate with a single power cylinder.
Alternatively, a separate power cylinder may be provided
for each arm, each having an upper end attached to an upper
side extension of the frame and each cylinder operating in the
inclined plane of movement of the respective arm.
The frame may include pivot brackets, generally
corresponding in position to the upper central region and the
lower laterally spaced regions, for direct connection to a
three-point hitch of a tractor. The conventional three-point
hitch allows the frame to be lifted and lowered without
tilting. However, a tilting movement of the frame may be
desirable, and may be achieved by replacing the normal upper
link of the hitch with a telescopic link, either manually
adjustable or incorporating a hydraulic cylinder which controls
its length. This allows the arms to have both the inclined
pivoting movement about their pivots and also to have a
vertical tilting movement provided by the tilting of the frame.
The tilting motion may be so controlled that the implements
carried by the arms move towards each other in a substantially
horizontal plane while the frame is gradually tilted.
The frame, or at least a main central portion of the
frame, is preferably triangular, having a base member and two
equal-length side members, the central upper region and lower
regions being at the corners of the frame, and the pivots
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carrying the inner ends of the arms are preferably aligned with
the side members of the frame. These side members are
preferably inclined at about 45° to the base member. In a
variation, the frame may have extensions on each side of the
main central portion, so as to be in the form of a "W" with
upper and lower apices joined by horizontal members.
Brief Description of the drawings.
Preferred embodiments of the invention will now be
described by way of example with reference to the accompanying
drawings, in which;
Fig.l shows a perspective view of a first embodiment of
apparatus according to the invention attached to the rear of a
conventional tractor;
Fig.2 is a rear view of the apparatus, detached from the
tractor, looking downwardly at an angle while the frame is
vertical;
Fig.3 is a side view of the same embodiment, also showing
a portion of the tractor hitch;
Fig.4 is front view of the apparatus frame on lines 4-4 of
Fig.3, with some parts of the apparatus removed;
Figs.5a, 5b, 5c, and 5d are views of implements which may
be used with the apparatus of this invention;
Figs.6a and 6b are side views of a second embodiment of
the invention in successive positions;
Fig.7 is a view on lines 7-7 of Fig.6a, showing the frame
of the second embodiment, with movable parts of the apparatus
removed;
Fig.8 is a fragmentary view of an alternative form of
telescopic link,
Fig.9 is a rear perspective view of a yet another
embodiment of the invention, without any implements, and
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Fig.lO is a side view of the Fig.9 embodiment, showing
digging implements in place in the arms.
Detailed Description.
As shown in Figs.l and 3, the apparatus 10 has a frame 12
adapted to be connected to a standard three-point tractor
hitch, and which normally occupies a vertical plane. The frame
12, as best shown in Fig.4, is formed of square steel tubing
and has a horizontal base member 12a and side members 12b
having their lower ends welded to the ends of the base member.
The side members extend at 45° to the base member and meet at
a right angled corner at the central upper region 13 of the
frame. The corners of the frame are provided with brackets
extending forwardly from the frame (i.e. towards the tractor)
and having pivots for receiving the tractor hitch members.
Specifically the upper corner of the frame has brackets 14
which pivotally connect to the upper link 20 of the hitch,
while the lower corners each have a pair of brackets 16 which
connect onto one of the two laterally spaced drag links 22 of
the hitch. This type of hitch has lift arms 24 connected to the
drag links 22 by lift links 25, and which can be used to raise
the drag links and thus lift the frame 12 while keeping this
generally vertical.
Each lower corner of the frame 12 also has a pair of
rearwardly projecting brackets 30, each pair of these brackets
having pivot bolts 31 supporting the inner end of an arm 32
formed of square tubing and extending rearwardly of the frame.
As best seen in Fig.4, these brackets 30 are arranged so that
pivot bolts 31 are orientated along the axis of the frame side
members 12b, i.e. are orientated at 45° to the normally
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horizontal base member 12a. Accordingly, the arms are
restricted to swinging movement in pivot planes which are
inclined at 90° to each other, and inclined at 45° to the
normally horizontal frame member 12a, the planes meeting at a
line of intersection which is situated below and symmetrically
between the lower corners of the frame and perpendicular to the
plane of the frame.
The arms 32 are of hollow square tubing, and an outer end
portion of each arm provides a hollow recess into which may be
inserted the square-sectioned stem 34 of an implement; for
illustration there are shown digging/ transplanting implements
35 of half-bucket form each having a main cutting blade 36
which slopes downwardly and inwardly so as to be generally
aligned with the plane of movement of the arm. The stem 34 is
retained in the arm 32 by removable pin 37.
The apparatus also includes a pair of levers 40, each of
which serves to support and control the movement of one of the
arms 32. Each lever has a triangulated structure including an
outer strut 40a, and upper and lower links 40b and 40c
respectively. The lower corner of each lever has a pair of
downwardly and inwardly sloping lugs 41 which are connected by
pivot 41a to a bracket 42 on the upper outer face one of the
arms 32 at a location spaced well away from its inner end and
preferably nearer its outer end. The lugs 41 allow some lateral
movement, as well as slight twisting motion, of bracket 42
relative to the lugs. These levers are pivotally supported on
the frame 12 adjacent its upper central region 13. The support
includes a pair of lugs 42 projecting rearwardly from the
region 13 of the frame and which carry a horizontal, transverse
pivot pin 43 which in turn carries a tiltable bracket 44, the
bracket including inner and outer plate portions 46a and 46b
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connected by a narrow web 46c. The inner and outer plate
portions enclose adjacent inner corners of the levers 40, and
the outer ends of these plate portions each carry a pivot bolt
48 for mounting the respective lever corner, these pivots being
parallel and horizontally aligned. This arrangement allows the
levers to act as links supporting the arms 32 and avoiding
undue stress on the pivots 31. The levers also provide powered
movement for the arms, by virtue of a hydraulic power cylinder
50 which is connected between brackets 51 extending from the
upper corners of the levers. It will be clear that, with frame
12 stationary, extension of cylinder 50 acting on the levers 40
will cause the arms 32 and implements 35 carried thereby to
move from a spaced apart positions along downwards converging
paths to the close together positions shown in broken lines in
Fig.2, in which the arms 32 are approximately parallel and the
lower ends of the implement blades 36 meet together.
In order for this pivot arrangement to operate without
much binding, at least over a reasonable range of arm movement,
say about 30° for each arm, the pivots are preferably arranged
so that not only the pivot bolts 31, but also the pivots 41a,
have axes oriented to pass through the upper central region 13
of the frame, and so that the axes of the lever pivots 43 and
48 pass close to this central region. In the preferred
arrangement shown in Figs.3 and 4, the axes 31x of the pivots
31 meet the horizontal axis 43x of pivot 43 at spaced points
which also lie on the axes 48x of the pivots 48, so that, at
each side, the three axes meet at a point.
This embodiment, with the implements 35 as shown, is
suitable for digging, or for transplanting a small tree, for
example as shown at T in Fig. 1. The operation would be started
with the cylinder 50 retracted to hold the arms spread apart
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with an angle of about 60 ° between them, and the tractor is
positioned so that implements 35 are on opposite sides of the
tree just above the ground. Cylinder 50 is then extended to
move the arms downwards and together, with the blades of the
implements digging into the earth and forming a V-shaped
enclosure for the soil around the tree root. When the tree is
suitably positioned in the implements 35, the lift arms 24 of
the tractor hitch may be operated to lift the apparatus and
with it the tree.
Normally, suitably shaped implements pull themselves down
into the soil with little need of downwards pressure being
applied. However, depending on the implements and the soil, a
digging operation may require that the tractor hitch be
equipped to maintain a downwards force on the apparatus. This
downwards force may be provided for by a hydraulic cylinder
which can be locked to prevent the apparatus frame from rising
during the digging operation.
The apparatus shown is based on the use of right-angled
triangles with equal length sides. For example, the frame sides
12b lie at 45° to the base 12a, and the length "1" of the side
12b is equal to the inner end portion of the arm 32 between the
bracket 41 and the arm inner end, as indicated in Fig.3, so
that the frame side 12b, the inner end portion of the arm 32,
i.e. inboard of the lugs 41, and link 40c form a triangle
similarly proportioned to the frame 12. However, other
proportions are possible, and the arms could be arranged to
pivot at other angles to the horizontal; it is expected that
useful results could be achieved with arms pivoting at angles
between 25° and 50° to the horizontal.
Figs. 5a to 5d show alternative forms of implements which
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CA 02201839 2002-O1-14
can be fitted into the arms 32 for particular tasks. Fig.5a shows
implements usable both for digging roots or for picking up rocks .
Fig.5b shows reversible :impl.ements which can be used in one
orientation as forks, and in the opposite orientation as spades.
Fig.5c shows implements designed for grabbing the ends of logs,
and :~ig.5d shows implements for gathering piles of brush, leaves,
wood, etc.
Figs.6a, 6b, and 7 show a further embodiment of the
invention which allows tilting of the frame and thus provides
1.0 additional forms of movements of the arms, particularly useful
where a gathering operation, rather than a digging operation, is
required.
As before, the apparatus of this embodiment includes frame
12', similar to frame 12, the arms 32, and the levers 40, these
being all the same as previously described except for the
mounting means for t:he frame. Instead of the brackets 14 and 16
of the first embodiment, here the front face of t:he frame 12' has
a pair of angle rnember_s 60 extending from the base member 12a up
to above the upper corner of the frame, and supporting a cross
pin 61 near their upper ends. Further pivot pins 64 are held at
the sides of the frame, at about one-third the frame height, by
lower brackets constituted by further pairs of angle members 65,
these being spaced f:or receiving the ends of the drag links 22,
and corresponding to brackets 16 of the first embodiment. The
bottom center of the frame has an additional horizontal pin 66
held by the lower ends of the angle members 60.
The frame 12' is made tiltable by replacing the usual upper
link 20 of the three-point hitch by a telescopic link 20' shown
in F:igs.6a and 6b. As shown, a sample form of te7.escopic link may
have a relatively fixed part in the form of an outer square tube
70 which receives a relatively slidable part. in the
form of an inner square tube 72, the outer end of tube 72 being
connected to pivot 61 while the usual drag links 22 are
connected to the laterally spaced pins 64. The tubes 70 and 72
have matching holes for receiving a retaining pin 73 and which
allow the link to be adjusted to various lengths. The retaining
pin 73 can be removed to allow link to extend and the frame to
tilt down about the pins 64. In addition, a spring operated
latch 74 pivotally mounted on the upper outer end of the tube
72 is capable of automatically engaging a lug 75 projecting
from the top of the tube 72. A hydraulic cylinder 77 is
connected between a bracket 78 on the underside of tube 70 and
the pivot pin 66 at the bottom center of the frame 12'.
As illustrated in Figs.6a and 6b, this arrangement is
particularly useful when it is desired to pick up material such
as bundles of wood 80 with implements indicated at 82 which are
intended to slide along the ground rather than to dig in. The
tractor is positioned, and arms 32 opened and lifted to
straddle the material, while the frame 12' is held in the
vertical orientation with latch 74 engaging lug 75. The latch
can then be released remotely by a cable C, and cylinder 77
allowed to retract so that the frame tilts down to the position
of Fig.6b, with the implements 82 on the ground at each side of
the material. Cylinder 50 is then operated to bring the arms
together. As the implements 82 slide together, the frame 12' is
caused to gradually tilt up and when the implements are in the
required position the tubes 70 and 72 can be locked together
with pin 73, after which the apparatus is lifted by the hitch
lift arms 24 and material 80 is moved to a different location.
If preferred, instead of locking the tubes with pin 73, the
cylinder 77 can be extended to tilt the frame back to the
vertical position at which the latch 74 engages lug 75.
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The cylinder 77 can also act as a hold-down device for
applying downwards force to the apparatus when this is needed
for digging into hard ground. It will be evident that the use
of the hydraulic cylinder 77 allows the frame 12', and
therefore the arms 32, to be tilted in the vertical plane while
cylinder 50 is inactive. This therefore increases the kinds of
movement which can be provided for the arms 32.
A cylinder such as 77 can also be merely a passive, shock-
absorbing type device for cushioning the tilting movement of
the frame 12' . This allows the latch 74 to be released when the
implements carried by the arms 32 are clear of the ground but
have been positioned on opposite sides of a pile of material to
be picked up from hard ground; in this case the cylinder will
allow the frame 12 and parts it carries to tilt down gradually
to the position shown in Fig.6b. The frame is caused to tilt
up to the vertical or near vertical position by inwards
movement of the arms as the implements slide along a horizontal
surface, and as before the frame can be locked in position by
pin 73. A passive device of this kind can also be used as a
hold-down device by locking it in its extended state.
Fig.8 shows an alternative arrangement in which the
telescoping movement of the tubes 70 and 72 is controlled by a
hydraulic cylinder 84 having one end attached to each of the
tubes. This allows complete control of the tilting action.
Figs.9 and 10 show a yet another embodiment of the
invention, which requires two hydraulic cylinders, and a wider
frame, but which is otherwise simpler in construction.
Here, each arm 132 is powered by its own cylinder 150,
although the cylinders will normally operate simultaneously.
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,~
The cylinders lie in the 45° planes of movement of the arms,
and have their upper ends connected to brackets 151 carried by
the upper corners of side extensions of the frame, which
corners are level with the upper central region of the frame.
These extensions are provided by an upper horizontal member 117
and by downwardly, inwardly sloping frame members 118 extending
at 45° to the horizontal, so that the whole frame is in the
form of a "W" with its apices connected by upper member 117 and
lower, base member 112a. The two lower corners of the frame
carry the arms 132 on pivot pins 131 held by brackets 130 and
which are aligned with the sloping inner frame members 112b,
corresponding to members 12b of the first embodiment.
In this embodiment, the supporting linkage is much
simplified compared to that of the first embodiment. It
comprises, for each arm, a link or tie rod 140c having its
outer, lower end welded to the arm 132, and having its inner,
upper end pivoted to the central region of the frame by
brackets 148 which carry pivots aligned with the main arm
pivots 131. The tie rods 140c perform a function similar to
that of the members 40c of the first embodiment, and prevent
excessive strain on the pivots especially when the apparatus is
used for lifting a load. As shown in Fig.lO, the frame has
brackets 14 and 16 for connection to a tractor, as in the first
embodiment, and can be moved by means similar to those
described for the first embodiment. Operation is therefore
similar to that of the first embodiment, the arrangement
providing forceful movement of arms 132, which can hold
implements 135 on stems 134 as shown in Fig.lO, in planes which
slope downwardly and inwardly to a line of intersection which
is situated below and between the pivots 131.
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