Note: Descriptions are shown in the official language in which they were submitted.
~ 1 3ns3l 9
STMP curr~
l. Field of the Invention
The present invention relates to stump cutters and root cutters for
clearing fields. M~re particularly, the invention relates to a light
weight too] for cutting stumps having a plurality of teeth of novel
configuration which are rotated at high speeds.
2. Background of the Invention
Conventional stump cutting and digging devices, which satisf~ the
requirement for power, generally have been of bulky construction
particularly ~ith respect to the boom cutters. This construction
~revents the cutter boom from removing tree stumps close to per~anent
obstructions such as building structures and prevents this devi oe from
being transported through, for instan oe , narrow gates of fenced
backyards. Accordingly, those skilled in the art have recognized a
significant need for a stump cutter and digging apparatus which overcome
the foregoing difficulties.
V.S. Patent No. 4,041,996 to Grover discloses an apparatus for
eradicating tree stumps comprising a rotary cylinder having cutters
around its periphery. The cutters are mounted on rings encircling the
cylinder.
U.S. Patent No. 4,214,617 to McKenry discloses a rotatable shank
upon which a traverse support bar is attached. Tbol holders are mcunted
in a distributed relation on the support bar and replaceable cutter bits
are mcunted on tool holders.
m e prior stump cutting or removing devices have the disadvantages
of being associated with heavy duty vehicles such as tractors, wheele~
vehicles or trailers. The operation of the entire system is pri~arily
` 130q319
by skilled cperators. The o~eration of the vehicle is costly especially
if it is made o~erational in order to remcve a single stu~p in a
constxuction area.
There is a need for a lightweight manually operated stump remover
which c~n be readily transported to far away sites, easily stored and
readily used by unskilled operators.
1 3093 1 9
Summar~ of the Invention
This invention provides an apparatus for clearing tree
stumps by cutting them down to a level below the surface of
the ground.
The invention also provides a small manually movable
tree stump eradicator which can be easily transported and
used by untrained personnel.
The invention further provides a tree stump eradicator
which can be utilized in difficult to enter locations and can
be easily transported.
The invention still further provides a stump eradicator
which does not operate on hydraulic power.
In accordance with the invention there is provided a
manually operated tree stump eradicator which comprises the
combination of a manually operated carrier having a rotatable
shaft and a cutting wheel means mounted on the shaft. The
cutting wheel means comprises a cutting wheel means which is
capable of being attached to a rotatable shaft. The cutting
wheel means at its lower end is provided with a plurality of
slot means carrying cutting teeth projecting outwardly and
facing in the direction of the rotation. The cutting teeth
are held within their respective slots by a cover means.
More specifically the invention provides a manually
operated apparatus for eradicating tree stumps and the like
comprising in combination: a manually operated carrier
member having a rotatable shaft; a cutting wheel means
mounted on said shaft, said cutting wheel means comprising a
grooved hub having a concave lower end and capable of
attaching to a rotatable shaft; said hub having at its lower
end a plurality of slot means; grooved cutting teeth mounted
in said slot means projecting radially outwardly from said
hub, said teeth having cutting faces facing in the direction
of rotation; and, a grooved convex cover plate mounted on
said hub for maintaining said teeth in said hub, said grooves
being in alignment with the grooves of said teeth.
A
1 3nq3l 9
In a preferred embodiment of the invention the cutting
wheel means is mounted on the shaft of a lawn mower type of
carrier. That is, the cutting means is mounted on the shaft
which would ordinarily carry the rotating grass cutting means
of the mower. Advantageously, the carrier pivots about a
wheel means so as to raise and lower the cutting wheel means
over a tree stump and to manually place the cutting wheel
means into position over the stump.
It is another feature of the invention to provide a tree
stump eradicator which can be quickly assembled or
disassembled, that is rugged in construction, simple in
design and operates with precision in small areas.
The cutting wheel means of the present invention can be
attached to the shaft of conventional law mowers in lieu of
their grass cutting means. The lawn mowers are of the type
which are manually propelled, self-propelled or of the riding
type.
A fuller understanding of the invention will be had by
referring to the following description and claims of a
preferred embodiment, taken in conjunction with the
accompanying drawings, wherein like reference characters
refer to similar parts throughout the several views.
l3n~3lq
Brief Description of the Drawings
Fiq. 1 is a perspective view of a wh~eled tree stump eradicator;
Fi5. 2 is a side view partially in section of the c~tting wheel of
Fiq. l;
Fig. 3 is a bottom view of the cutting wheel;
Fia. 4 is a side view partially in section of the cutting means of
Fig. 2 ~ithout cutting teeth and lcwer plate;
Fig. 5 is a top view of the cutting wheel;
Fig. 6 is a bottcm view of the cutting wheel withcut bottom plate
and cutt-~g teeth;
Fig. 7 is a side view partially in section of the bottom plate of
the cutting wheel;
Fig. 8 is a top view of the bottom plate; and,
Fig. 9a and 9b show the cutting teeth of the invention.
1 30931 9
Description of the ~ E~t ~I:rrr:t of the Invention
Alth~ugh s~ecific terms are used in the following description for
the sake of clal-ity, these terms are intended to refer only to the
particula structure of the invention selected for illustration in the
drawings, and are not intended to define or limit the scope of the
invention.
Pig. 1 illustrates a tree stump eradicator 10 of the invention
which ccmprises a cuttinq asse~bly 11 which ic associated with a
manually operated carrier 12. The c~rrier 12 is preferably provided
with whee' mezns 13 on a carriage 14 for movement along the grcund.
Mourted on the carriage 14 is a motor 15 that rotates a shaft which
causes operation of the cutting assenbly 11. Optionally, the motor 15
is also c~nnected for driving the wheel means 13 so as to make the stlmp
eradicatlng apparatus 10 self-propelled. Motor 15 can comprise two
separate motors.
The carriage 14 is mounted so as to pivot about the axle 17 of the
wheel means 13. Pivoting and movement of the apparatus 10 is controlled
by means of handles 16 which are attached to the carrier 11.
The cutting assembly 11 is driven by the shaft 16 through an
adjustable coupling 18 with adjusting means 19, for example a tightening
adjuster nut. Coupling 18 permits the angular adjustment of the cutting
assembly 11 with respect to a tree stump. The cutting wheel asse~bly 11
comprises a housing or head 20 which is attached to a suitable connector
21 of the shaft or coupling 18. At the lower end of the cutting head 20
and proje~ting outwardly is a plurality of cutting teeth 22. The
cutting head 20 has at its lower end a removable bottom plate 23 for
access tc the teeth 22. m e coupling 18 generally includes a bearing
, .. ~c; .. ..
1 30q3 1 9
block 60, ~tich may for example be two thl~lst bearings, in which a shaft
o~erated b~- the motor 15 is jcurnaled.
If desired, the cutting wheel asse~bly 11 mav be conn~cted directly
to a sh2ft ~lich is rotatively powered by the motor 15. In which case,
the cuttina wheel asse~bly 11 should be positioned at an angle to
provide an effective cutting. it has been found that suitable cutting
angles for the cutting wheel assembly 11 is between 15 and 30 degrees
with respect to the ground.
The tree stump eradication 10 may be provided with other
conventic..al features such as fcund on lawn m~wers. For exam~le, a
shield 25 near the cutting wheel asse~bly 11 as provided to protect the
operator from cutting debris. There may also be provided a stand 24 and
a cover means 25.
Fig. 2 is a partially broken away cross sectional view of the
cutting wheel asse~bly 11. The cutting wheel assenlbly 11 is composed of
a cuttina head generally designated as 20, cutting teeth 22 and a bottom
plate 23 which is connected to the cutting head 20 by a recessed
thread æ bolt 25. The cutting head 20 is provided with internal threads
28 for attachment to a journaled shaft or the coupling 18. ~he threads
28 run cc~nter to the rotation of the asse~bly 11 so as to prevent
loosening during operation. As illustrated, the lower plate 23 with
ridaes 35 cooperate with associated grooves 30 on the cutting teeth 22
so as to hold the teeth 22 firmly in the cutting wheel assembly 11. If
desired, the teeth 22 can be extended outwardly by advancement on the
ridges 35.
Fia. 3 shows a bottom view of the cutting wheel assembly 11.
Preferabl~, the teeth 22 are spaced substantially ea,uidistant around the
l3ns3ls
periphery. The teeth 22 are prc~ided with a cutting edge 31, and
preferably each is provided with a drop off on the shoulder of the teeth
forming ar, angle a of lO tc 30 degrees, ~,nost preferably 30 degrees.
Hcwever, for different types of wood, different shapes of cutting edges
may be used.
Fig. 4 illustrates a further en~xxl~nent of the invention wherein
the lower portion of the cutting head 20 is provided with grooves 32 and
ridges 40 so t'hat the grooves are substantially continuous around the
cutting head 20 when the teeth 22 lock in V-groove compression together
~ith the bottom plate 23. The bottcm portion 37 of the cutting head 20
is concave or beveled since an angle permits better aripping and support
of the teeth 22 during the cutting operation when used in combination
with an associate grooved and beveled lower plate.
In Fig. 6 there is shc~n slots 36 at the lcwer end of the cutting
head 20. The cutting head 20 is provided with V-shaped grooves 32 and
ridges 40 circling the bottom portion except for the slots 36. The
teeth 22 ~hen placed in the slots 36 will have their grooves 30 in
alig~nent with the grooves 32 of the cutting head 20. The cutting head
2n is further provided at one end with an internally threaded bore 28
for attachment to a coupling or shaft for rotating the cutting head 20.
At the other end there is provided a threaded bore 34 for re oe ivinq the
bolt 25 ~ich attaches the cover means 23.
Fiqs. 7 and 8 show the end plate 23 which is attached to the
cuttina head 20 by means of a bolt 25 that is inserted in the recessed
bore 41. m e end plate 23 has a pluralit~ of circular grooveC 42 and
ridqes 35 which are positioned so as tc be associated with the V-grooves
32 and ridges 40 of the cutting head 20. The end plate 23 is preferably
1 3093 1 ~
~slightly ~e~eled so as t~ be associated with concave configuration of
the bottom portion of the cutting head 20.
Althcugh the pea~s 35 are shohr. as being rounded, it is possible to
utilize V-shaped peaks in the invention. It has been found to be
advantagecus to round off the peakc to permit a better distribution of
stresses and to prev~nt chipping. A150, the cover plate is slightly
beveled or convex so as to cooperate with the concave configuration of
the lcwer portion of the cutting head 20. The use of the slight concave
configuration for the bottom of the cutting head 20 in combination with
the sligh- conve~: configuration (about 6-12) of the plate 23, per~its
the distribution of the stresses which occur on the cutting teeth 22
during tree stump eradication.
Figs. 9a and 9b illustrate a typical cutting tooth 22 which may be
used in the invention. It has been fo~nd that cutting teeth having a
sloped shculder of about 10 to 35, preferably 30, are more effective
with soft wood. A 10-15 degree slcpe is preferable for h~rd wood.
Block or square teeth and rounded teeth are e~ually effective. When the
r~tatior of the cutting head is between 2400 and 2600 rpm, the teeth
perform similar to a chain saw. The teeth 22 are preferably comprised
of harde~ed steel with a carbide cutting edge. When the cutting teeth
22 are placed in the slots 36, the grooves 29 of the teeth 22 are in
alignment with the grooves 32 of the cutting wheel ll. The botto~ plate
23 is pl2ced SO that there is a mating of the associated peaks an2
valleys. The plate 23 is tor~ued down with the bolt 25 so that the
V-shaped ridges 40 of the cutting wheel 11 fit into the grooves 29 of
the bottom plate 23.
_9_
1 30931 q
In operation, when the teeth 20 are place~ into the slots 36 of
body 20, the grooves 19 of teeth 22 are generally 0,015" above the
ridges 40 and grooves 32. The rounded ridges 35 on cover plate 23 make
contact with grooves 29 first because they are raised. When cover plate
23 is torqued dc~n with bolt 25 to about 70 ft lbs, the ridges 35
compress into the grooves in teeth 29 and never bottom out on ridges 40
and grooves 32 even though ridges 30 on ccver 23 start their entry in
the V-grooves of body 20. This ensures ccmplete contact and compression
of teeth 32 in slots 36 of body 20.
Although the invention has been described with a oe rtain degree of
particularity, it is understood that the present disclosure has been
made only by way of example and that numerous changes in the details of
construction and the ccmbination and arrangement of parts may be
resorted to without departing from the spirit and scope of the
invention.
--10--
