Note: Descriptions are shown in the official language in which they were submitted.
LAWN SCARIFIER AND RAKE
Background of the Invention
It has been determined that in order to
produce and maintain a high grade lawn, it is
necessary to provide the conditions which will
encourage the growth of the finer turf grasses. Such
conditions, however, at the same time should be
hostile to the coarse and surface creeping grasses
which are both unsightly. If not controlled such
grasses will choke out the finer growth.
Past experience has demonstrated that two of
the operations which are essential to achievlng these
conditions are periodically scarifying the turf in
order to remove dead mat and moss. The second
operation includes the regular raking of the surface
of the lawn to lift up the stolons of creeping
grasses and weeds so that these can be cut short by
subsequent mowing or scything or provlsion msy be
made for uprooting the offenslve grasses and weeds.
It is also necessary from time to tlme to remove
sur~ace clebris such as leaves, twigs and small stones.
It will be obvious that for the average
amateur gardener the only means available for
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performing,these tasks ~s laborious hand raking with
- a wire rake or similar tool, or brushing and remov,al
of the debris by hand in order to produce a well
manicured lawn. These operations are both very time
consuming and extremely tiring so that relatively few
gardeners are able or willing to perform them as
often as is needed or desirable. Furthermore, it is
generally recommended that moss should be chemically
k~lled before removal to prevent the moss from
spreading, requiring yet another operation.
Mechanical scarifying equipment is available
for professional use on golf courses, sports grounds
and the like, but such machines require a certain
degree of skill to operate and in unskilled hands
could cause excessive damage or be themselves
seriously damaged by striking hard obstructions or
surfaces. They are also generally too heavy and
cumbersome for use in the confined areas of the
average domestic garden and do require that the turf
should be reasonably free from undulations. Finally,
of course, as would be expected such equipment is
very costly.
Although hand propelled rotary brushes and
suctlon cleaners are avallable for clearlng surface
debris they have no other use and can only be
~ustlfied if large areas of turf are involved.
Summary of the Invention
The present invent$on pertains to a device
whlch ls a mechanical lawn scarifier and raker,
particularly suitable to the needs of the home or
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amateur gardener. It enables all of the functions of
scarifying, raking, brushing and collecting of debris
to be performed more effectively, in a much shorter
time and with very much less physical effort than by
the use of conventional hand tools. The device is
light in weight and easily manipulated making it
suitable for use in confined spaces and small areas
as well as on more extensive stretches of turf. Its
operation requires no great skill, mechanical
aptitude or physical strength and it cannot do
excessive damage to the turf or be damaged by
traversing hard surfaces such as brick or stone paths.
A typical embodiment of a mechanical lawn
scarifier and rake in which this invention is incor-
porated comprises a cylindrical rake rotatably mountedin a frame or supported by wheels and by a roller, the
latter adapted and constructed to control the height
of a raking helix relative to the ground surface. The
raking helix describes a cylindrical configuration
consisting of two or more rows of radially disposed
teeth or tines positioned symmetrically and helically
about, and suitably attached to, a central horizontal
shaft or spindle. When the cylinder i9 rotated the
tines are forced through the surface of the turf to a
depth which can be pre-set by a suitable means of
adjustment according to requirements. The helix
angle of the rows of tines is such that the first
tine in any one row is in the same axial plane as the
last tine of the preceding row, thus ensuring a
substantially constant torque resistance. In use,
the tine carrying means is rotationally driven by an
electric motor or other suitable power source at a
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speed sufficient to ensure that when the machine is
propelled forward at a normal walking pace successive
tines make contact with the turf in a substantially
continuous line.
It will be appreciated that the power source
may also be employed to propel the device in a
forward direction by driving the wheels or rollers.
The preferred embodiment contemplates that it should
be hand propelled and therefore a suitable upright
inclined handle is provided. Thereby the forward
speed can be instantly ad~usted according to
condit$ons and at the same time the device can be
given a reciprocating motion, that is, can be moved
repeatedly forwards and backwards over stubborn areas
of moss, dead mat and/or unwanted growth. In fact
the direction of rotation of the helix is such that
forward propulsion is somewhat assisted thereby
reducing the effort required by the operator of the
devlce.
If the teeth or tines were rigid elements
and, further, rigidly attached to a central shaft
there would undoubtedly be excessive or inadequate
penetration into the turf through slight errors in
setting the height or where undulations ln the
surface contours occur. Concomitantly, there would
also be enhanced risk of permanent distortion or
breakage of the tines if solid obstructions were
encountered. It is therefore a salutary feature of
the present invention that the tines, while being
stlff enough to ensure adequate scarification, are
nevertheless sufficiently flexible to withstand
considerable deflection both forwards and backwards
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relative to the direction of rotation. This feature
permits some latitude in setting the height without
unduly affecting performance and avoids any risk of
damage to the tines.
The device may be set whereby the helix
supplies vigorous scarification to the surface and
due to the flexibility of the tines will not actually
result in Aigging up the soil. Alternatively, when
it is only required to remove surface debris, the
10 device may be set whereby the tines of the helix are
clear of the qround so that no untoward damage to the
grasses will occur.
A further advantage of employing flexible
tines is that having been deflected backwards
15 relative to the direction of rotation on entering the
turf, the tines spring forward on leaving it with a
much higher top velocity than that imparted by the
rotation of the helix, thus projecting the debris
upwards and into a supplied bin with greater force
than would otherwise be achieved. This debris is
then guided by a curved deflector plate into the bin
suitably mounl,ed on the forward portion of the
device. The bin is designed for easy removal for
disposal of the contents in much the same way as the
25 grass catcher on a conventional lawn mower. As most
of the debris is collected in the bin, it is not
essential to exterminate the moss prior to its
removal as its spread is defeated and prolonged and
frequent use of the device will greatly discourage
its re-establishment.
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5a
Thus, in one aspect the invention provides
a turf scarifier and raker device having a carriage
and a helical tine assembly rotatably mounted in the
carriage, a prime mover operatively connected to the
tine assembly for rotating the latter, the improvement
being characterized by the tine assembly including: a
frame having central support means and helix means
disposed in surrounding relation to said central support
means; said helix means including at least one rod
radially of the central support means, the rod subtending
a helical angle about the axis of the central support
from one end of the rod to the other; and a plurality of
coil springs threaded on said rod, each of said coil
springs terminating in respective ends, the first one
of said ends defining a tine extending substantially
in the radial direction and adapted to engage the turf
when the device is operated, and the second one of
said ends defining an arm disposed between the helix
means and the support means, the arm having an abutting
engagement with and substantially tangentially of said
central support means in response to a deflection
movement applied to said tine when said device is moved
over the turf.
Further aspects will be apparent from the
claims appended hereto.
6.
Brief Description of the Drawin~s
The invention will now be described with
reference to the drawings wherein:
Figure 1 is a perspective view of the lawn
scarifier and raker;
Figure 2 is a side elevation view of the
side having the transmission with the area of
interest broken away;
Figure 3 is a top plan view with points of
interest in fragmentary form;
Figure 4 is a top plan fragmentary view to
show shift of front wheels;
Figure 5 is a fragmentary side elevation
partially broken away to show area of interest;
Figure 6 is a cross-sectional view of the
tine carrying helix arrangement;
Figure 7 is a perspective of the tine
carrying helix arrangement in fragmentary form;
Figure 8 is a perspective view in
fragmentary form of another embodiment of the helix
arrangement;
Figure 9 is a side elevatlon of the other
embodiment of the helix arrangement wlh an area of
lnterest in cross-section;
Figure 10 is an end view of one of the tine
carriers of the said other embodiment;
Figure 11 is a view of the other end of the
tine carrier of the said other embodiment.
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Detailed Description of the Invention
Including Various Embodiments Thereof
Attention is directed to Figure 1, at the
first instance, for a consideration of the device
shown, generally, by reference numeral 10 hereinafter
to be discussed. The device includes a carriage 7
encompassing a carriage or housing 11 which may be
constructed of metal or the like. It has side walls
9 and a top portion 8. The housing 11 has a handle
mounting means 12 at each side of the upwardly facing
portion of the housing to which the yoke portion
upstanding of a bifurcated handle 13 is pivotally
secured.
The device 10 is supported on turf 14 at the
rear by means of a rearwardly positioned elongated
roller 15 which has axle means having ends which fit
into ad~ustable support means located inside
rearwardly extending portions 16. At the forward
portion 17 of the housing, the device is supplied
with wheels lB which in one embodiment are secured to
stub axles horizontally secured internally of the
forwardly extending portions 17 of the houslng 11.
The houslng 11 has a large substantially
rectangularly shaped openlng 19 in the top portion 8
at the forwardly extending portlons 17 of the housing
11 through which debris and grass may be hurled when
the devlce 10 is operated.
The houslng 11 has a bridging portion 20
between the aforementioned forwardly extending
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portions 17. Figure 1 shows that the device 11 can
be provided with an upwardly open facing catcher 21
which has relatively substantial side walls 22 and a
frontwardly facing wall 23 and a relatively minor low
wall 24 at ~he side facing the opening 19 of the
housing (seen more aptly in Flgure 2). The catcher
or bin 21 possesses rearwardly extending arms 25
which are integral with the side walls 22 thereof.
Each arm 25 terminates in a hook 26 adapted to
hookingly engage a retaining member 27 mounted at the
top and side portions of the housing.
A tine assembly 28 is seen through the
aforementioned opening 19. The arrows shown on the
drawlng describe the rotation of the tine assembly 28
when the device is operated. It is this tine
assembly 28 that is adapted and constructed to
effectively hurl the debris and/or grass material
through the opening as a result of its being
rotatably driven by an electric motor 29 (see Figure
5). The electric motor 29 is located in back of the
tine assembly 28 and is suitably enclosed by the
housing 11. The axis of the motor is substantially
in the same horizontal plane as the rotational axis
of the tine assembly 28. The transmission means 30
between the tine assembly 28 and the electric motor
includes a belt 39 as wlll be discussed below.
The upper surface of the housing 11 has,
seen from Figure 1, an electric conduit 31 which is
secured to the handle 13 by clips 32.
Having considered the overall configuration
of the devlce as can be best discerned from Figure 1,
attention is now more particularly directed to the
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other figures for an even more detailed
consideration. Note, for instance, from Figure 2
that the handle 13 converges to a single hand grip 3
having along the bottom portion an electric finger
operated swltch 34. The end of the handle has
pro~ecting therefrom a relatively short electric
cable 35 terminating in a male plug 36 which may be
plugged into the female portion of an extension cord
(not shown).
The transmission 30 will be seen to be
covered with cap 37 removably secured to the side 9
of the houslng 11 by conventional means. Therefore
external to the housing 11 is the drive gear 38
operatively mounted to the drive shaft of the
electric motor 31. A timing type belt 39 operates
off this drive gear 38 and around the driven gear 40
which is operatively connected to the tine assembly
28. A number of other features can be seen from
Figure 2 that were mentioned above when discussing
the posltioning of the catcher 21 for instance,
especially see the manner of hooking of the catcher
21.
From Figure 3 it will be seen that the tlne
assembly 28 ls sultably Journaled in bearlngs 41
located at opposltely disposed po$nts of the side
walls 9. An externally located cap 42 is provided
externally at the side wall opposite the transmission
30 to protect one of ths bearlngs 41 but is
accesslble for lubrlcation.
Note the manner of mounting the stub axles
43 at opposing sides of the ~orwardly extendlng
portion 17 of the houslng 11 for the wheels 18. In
another embodiment, as depicted by Figure 4, the
wheels 18 are mounted on an axle 44 that is
conventionally mounted in place of the stub axles.
By providing a single axle 44, the wheels 18 may be
moved therealong somewhat as shown in Figure 4. When
a lawn is to be traversed that possesses a crown or
ridges, more closely associated wheels will have more
of a tendency ,to ride on such crown or ridges thereby
obviating possible scalping effects that may
otherwise occur. While the wheels may be located
anywhere on the axle, notches are provided to accept
spring loaded balls in the bore of the wheels so that
the wheels may be positioned in association with such
notches and will be retained thereby to prevent
migration o~ the wheels slong the axle.
As can be seen ~rom Figure 3, the rearwardly
positioned roller 15 is essentially a hollow cylinder
mounted on an axle 45 that is restrained into one of
several notches 46 in a plastic block 47 secured
opposingly and internally of the rearwardly extending
portion 16, as can be seen from Figure 5. As stated
the axle 45 is restrained by a hinged clip 49 that is
hinged at the bottom and clasps the block at a raised
port$on 48. By moving the axle 45 of the roller 15
to one o~ the two notches 46 depicted ln the block as
shown ln Flgure 5 the roller 15 controls the he$ght
or the housing 11 above the grass and thereby the
height o~ the presentatlon of the tine assembly 23.
Figure 5 is also use~ul in depicting the
fact that a secondary internal housing 50 is provided
in which the electric motor 29 is secured in a manner
to a~ord protection from the ambient. The ~orward
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portion 9 of the internal housing 50 has an arcuate
forwardly facing wall 51 which foilows the arc
produced by the tine assembly 28 when it rotates and
is slightly separated from the tine assembly 28.
This arcuate wall 51 acts as a direction imparting
chute for the debris and grass picked up by the tine
assembly 28, more about which will be disclosed
immediately in the following.
Having been apprised of many of the features
of the invention, attention is now additionally
dlrected to the ingenious tine assembly 28 about
which much has heretofore been alluded. From Figure
3, it will be seen that the tine assembly includes
central support means in the form of a central axle
52. The central axle 52 has rigidly fixed thereon in
radial fashion three angularly spaced triangularly
shaped plates 53, as can more readily be seen from
Figures 6 and 7. One plate is located at the end
portions of each of the ends of the central axle 52,
and the third plate centrally therebetween. Each of
the three plates have axial bores near their
respective apex portions to accommodate helix means
in the ~orm of three rods 54. Each rod has an end
suitably attached at a bore of one end plate, then
each passes through a bore of the middle plate and
each is then secured through a bore of the opposlte
end plate by a suitable means as by welding or upset
metal deformation. The plates 53 by their positions
produce a trlpartlte helix as can be seen from Figure
3. From Figure 3 it can be ~urther discerned that
each o~ the rods 54 has serially threaded thereon a
plurality of tightly wound torsion coil springs 55,
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each has an active end 56 that terminates in a hook
57 defining a tine 58 and an essentially passive end
60 that has a sharply bent portion 61 and an
elongated stralght portion 62. The active end 56
extends substantially radially outwardly while the
passive end 60 has a portion of its straight portion
62 in tangential abutment against the central axle 52
as can be seen from Figure 6 when stress is applied
against the tines 58.
The ~ragmentary portion of the tine assembly
28 shown in Figure 7 demonstrates succinctly that the
said torsion coil springs 55 are threaded on the rods
54 in a manner so that each is disposed in the same
direction as regards the respective active and
passive ends. Each rod 54 passes helically through
an angle of 120 in the length of the tine assembly
28 so that that first tine 58 in any one row is in
the same axial plane as the last tine 58 in the
preceding row.
In operation, the passive end 60 of each
tine is restrained by being located between the
central axle 52 and an ad~acent row of tines. The
active end 56 by having a slight hook 57 affords a
more effective removal of material from the turf.
The deslgn of the torsion coil springs 55 is such
that its active ends 56 will withstand considerable
torsional deflection in either direction with low
relative risk of permanent distortion or breakage or
of stressing the metal of the springs beyond the
fatigue limit. The clearance between the coils and
the rods 54 is ~ust sufficient to prevent the springs
55 from locking at full deflection but small enough
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to give adequate lateral support to the active ends
56. Of course the coil springs absorb the turn~ng
moment imparted to the active ends 56 thereby
inhibiting deflection.
Attention is now directed to Figures B to
11, for a detailed consideration of an ingenious
embodiment incorporating new and additional
principles. In this embodiment the tine assembly 28A
lncludes only a single central axle 70 mounted by its
respective end portions 71 thereof in journaling
fashion as with the aforementioned tine assembly.
An end radial driving plate 72 is suitably
affixed to one end portion of the axle 70 as by
weldlng or the like. The plate 72 has three equally
spaced apertures 73, the use of which will be
discussed hereinafter. In this embodiment the coil
springs 74 of a slightly different configuration, are
carried by a carrier 75, which may be fabricated of
metal or a polymer such as nylon. The carrier has
the general shape of a disk having a front 76 and
back 76, an axial bore 78 therethrough and a
substantial outer circumference 80. The bore is of a
dlameter whereby it ~its smoothly onto central axle
70.
From Figure 11, particularly, it can be seen
that each of the carriers 75 has three outwardly and
front facing recesses 81, of a generally U-shaped
configuration with one wall 82 comprising one leg
shorter than the other wall 83 comprising the other
leg. Each of the recesses possesses a post 84
extending axially with regard to the carrier 75 and
has a portion 85 extending beyond the front face 76
as can be seen from Figure 11.
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14
.
A coil spring 74 is axially positioned onto
each of said posts 84. The coil springs 74 has an
active end 86 as heretofore extending out of the
recess 81 along the shorter wall 82 of the recess.
The reactive end 87 of the coil spring extends along
the other longer wall 83 of the recess. The active
end 86 terminates in a hook 88. The hook 88 operates
in the same manner as heretofore and is inhibited
from undue deflection by the reactive end 87 in
abutment against the longer wall 83 of the recess
when the rotation imparted to the carrier 75 as seen
in Figure 11 is counterclockwi~e.
Now, viewing Figure 9 and 10 together, it
can be seen that the back of carrler 75 has three
equidistant blind bores 90 which are dimensioned and
positioned to receive and retain that portion 85 of
the post 84 extending beyond the front 76 of the
carrier to thereby provide a wall to the recesses 81
and to thereby retain the coil spring on the post
84. The recesses 81 have the appearance of pockets.
Turning to the perspective of Figure 8, the
first disk carrier 75 threaded onto the axle 70 is
positioned whereby the portions 85 of the post
extending beyond the front of the disc carrier is
permitted to extend into and through the apertures 73
of the end plate 72. The second or next disc carrier
75A is then threaded onto the axle 70. However, as
the blind bores 90 are offset by about 6 from the
aperture 73 of the plate 72, the second disc carrier
75A is angularly offset from the first disc carrier
that has been threaded on the axle 70 thereby the
radially outwardly facing recesses 81 of the second
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disc carrier 75A are in a different angular position
from the recesses 81 of the first disc carrier.
Likewise the third disc carrier 75 B (See Fig. 9)
mounted on the axle 70 again has its three blind
bores 90 further offset by 6 so that there is a
progressive 6 incremental change in the positioning
of the radially outwardly facing recesses 81 as can
be seen from Figure 9, for instance. In other words
the blind bores of the disc carriers when assembled
are not in linear axial alignment parallel with the
axle.
When all of the disc carriers 75 have been
threaded in the progressive manner herelnabove
mentioned, an end disc locking plate 91 is secured
against the stack of disc carriers and a nut 92 is
threaded onto suitable threads 93 of the end portion
71 of the axle whereby the disc carriers are clamped
between the end driving plate 72 and the end locking
plate 91. The resultant is a unitary device having
outwardly radiating tines produced by the active ends
86 of the coil springs. The gradual 6 incremental
arcuate progression of the recesses 75 and the
concomitant active ends of the coil sprlngs 74
describes a helix of tines.
As the carriers themselves are not keyed
directly to the axle, it will be seen that the
carriers are rotatably driven when the axle is
rotated by virtue of the driving plate 72 which
carries the extending portions 85 of the posts of the
flrst carrier. Llkewise, then all the other carriers
are locked together in the manner as heretofore
stated culminated with the end locking plate 91 to
provide a unitary stack rotatable in unison with the
axle when it is driven.
