U.S. patent application number 12/500143 was filed with the patent office on 2010-01-07 for mowing head with peripheral members for engagement of the cutting line.
This patent application is currently assigned to ARNETOLIMOTOR DI ARNETOLI FABRIZIO. Invention is credited to Fabrizio ARNETOLI.
Application Number | 20100000099 12/500143 |
Document ID | / |
Family ID | 38516235 |
Filed Date | 2010-01-07 |
United States Patent
Application |
20100000099 |
Kind Code |
A1 |
ARNETOLI; Fabrizio |
January 7, 2010 |
MOWING HEAD WITH PERIPHERAL MEMBERS FOR ENGAGEMENT OF THE CUTTING
LINE
Abstract
The mowing head (1) includes: a body (3), which can be engaged
to a motor shaft and defines a peripheral edge (3C); at least one
member for anchorage (9) of a cutting line (F), with an elastically
loaded eccentric oscillating element, which co-operates with a
surface of contrast fixed to the body for anchoring the cutting
line. The oscillating element (11) projects from the peripheral
edge of the body of the mowing head with a knurled edge (11Z),
which forms a gripping surface for causing oscillation of the
oscillating element and release of the cutting line.
Inventors: |
ARNETOLI; Fabrizio;
(Firenze, IT) |
Correspondence
Address: |
McGLEW AND TUTTLE;John James McGlew
Scarborough Station
Scarborough
NY
10510-9227
US
|
Assignee: |
ARNETOLIMOTOR DI ARNETOLI
FABRIZIO
|
Family ID: |
38516235 |
Appl. No.: |
12/500143 |
Filed: |
July 9, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11531131 |
Sep 12, 2006 |
|
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12500143 |
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Current U.S.
Class: |
30/347 |
Current CPC
Class: |
A01D 34/4166
20130101 |
Class at
Publication: |
30/347 |
International
Class: |
A01D 34/416 20060101
A01D034/416 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 13, 2005 |
IT |
FI2005A000191 |
Claims
1. A mowing head for accommodating at least one piece of cutting
string, the string being fixedly supported in the mowing head, the
mowing head comprising: a base plate; a continuous side wall
extending from said base plate with no apertures, said wall
defining one clamping chamber with a contrast surface for each
piece of string; a cam for each piece of string, said cam being
partially contained in said clamping chamber, wherein a portion of
said cam is located outside of said side wall, said base plate and
said cam defining a peripheral edge, said cam being manually
actuatable from said peripheral edge.
2. A mowing head for accommodating at least one piece of cutting
string, the string being fixedly supported in the mowing head, the
mowing head comprising: a first base plate; a second base plate; a
side wall between said first base plate and said second base plate,
said wall defining one clamping chamber with a contrast surface for
each piece of string; a cam for each piece of string, said cam
being partially contained in said clamping chamber, wherein a
portion of said cam is located outside of said side wall, said cam
being manually actuatable from a peripheral edge of said side
wall.
3. A mowing head in accordance with claim 2, wherein said first
base plate is detachably connected to said second base plate.
4. A mowing head in accordance with claim 3, wherein said cam is
located between said base plate and said second base plate.
5. A mowing head in accordance with claim 2, wherein said first
base plate is non-detachably connected to said second base plate to
form an integral mowing head structure.
6. A mowing head in accordance with claim 2, wherein said cam
comprises a knurled surface, said knurled surface defining a user
contact means for actuating said cam.
7. A mowing head in accordance with claim 6, wherein at least a
portion of said knurled surface extends in an outward radial
direction from said peripheral edge of said side wall.
8. A mowing head for accommodating at least one piece of cutting
string, the string being fixedly supported in the mowing head, the
mowing head comprising: an axis of rotation; a base plate; a
continuous side wall extending from said base plate, said side wall
having no apertures, said side wall comprising a contrast surface,
said side wall defining one clamping chamber with said contrast
surface for each piece of string; at least one oscillating
eccentric cam per piece of string, said at least one oscillating
eccentric cam having an oscillating axis, said at least one
oscillating eccentric cam being at least partially contained in
said clamping chamber, said at least one oscillating eccentric cam
being located outside of said side wall, said at least one
oscillating eccentric cam being manually actuatable from a
peripheral edge of said side wall, said oscillating axis of said at
least one oscillating eccentric cam being located in said clamping
chamber, said contrast surface and said axis of rotation defining a
first radial distance, said oscillating axis and said rotation axis
defining a second radial distance, said first radial distance being
greater than said second radial distance.
9. A mowing head in accordance with claim 8, further comprising
another plate connected to said base plate.
10. A mowing head in accordance with claim 9, wherein said at least
one oscillating eccentric cam is located between said base plate
and said another plate.
11. A mowing head in accordance with claim 9, wherein said base
plate is non-detachably connected to said another plate to form an
integral mowing head structure.
12. A mowing head in accordance with claim 8, wherein said at least
one oscillating eccentric cam comprises a knurled surface, said
knurled surface defining a user contact means for actuating said
cam.
13. A mowing head in accordance with claim 12, wherein at least a
portion of said knurled surface extends in an outward radial
direction from said peripheral edge of said side wall.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation under 37 CFR 1.53(b) of pending prior
application Ser. No. 11/531,131 filed Sep. 12, 2006, and claims the
benefit of priority under 35 U.S.C. .sctn. 119 of Italian Patent
Application FT 2005A000191 filed Sep. 13, 2005, the entire contents
of each of the applications are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to improvements to mowing or
trimming heads for brush cutters or the like, and more in
particular to mowing heads that use cutting line elements for
cutting vegetation.
BACKGROUND OF THE INVENTION
[0003] In gardening, frequently tools are used for cutting
vegetation, and in particular for cutting grass, which are based
upon the use of cutting lines. The latter are made to project
radially from mowing heads, which, fitted to the end of a rotating
shaft, are made to rotate at a high speed. The centrifugal force
radially extends the lines projecting from the mowing head, so that
by rotating they cut the vegetation.
[0004] In some mowing heads of this type, the cutting line is
applied in the form of single lengths, one end of which is anchored
to the mowing head whilst the opposite end projects radially from
the mowing head itself. The length of the individual lengths or
portions of cutting line is sufficient to carry out cutting of a
certain amount of vegetation. Once the lengths of cutting line are
worn out, they are simply replaced with new lengths. Examples of
mowing heads of this type are described in the U.S. Pat. Nos.
5,896,666, 5,758,424, 5,887,348.
[0005] The mowing heads described in the above U.S. patents have a
rotating body, which can be engaged to a motor shaft and defines a
peripheral, i.e., perimetral edge, along which members for
anchorage of lengths of cutting line are arranged. Each anchorage
member has an eccentric oscillating element elastically loaded
against a surface of contrast fixed to the body of the mowing head.
The length of cutting line is blocked against the mowing head as a
result of the elastic loading exerted by the eccentric oscillating
element against the contrast surface. The centrifugal force that is
generated during rotation, which is applied on the cutting line
projecting from the mowing head and tends to slide the cutting line
out of the seat defined between the fixed surface and the eccentric
element, increases the force with which the eccentric element
presses against the fixed surface, pinching the cutting line. This
guarantees effective grip of the cutting line during operation.
[0006] These devices do not enable a convenient removal of possible
residue of the cutting line, which can remain blocked in the
anchorage member and that must be replaced with new lengths of
cutting line. Furthermore, the operations of production and
assembly of the anchorage members are complex and far from
reliable.
[0007] In some practical embodiments of the above known devices,
manufactured by the company Kwik Products, Inc., USA, to enable
release of the cutting line and replacement of a worn-out cutting
line with a new one, the eccentric elements have a dorsal tab,
which projects in the direction of the axis of the mowing head, and
on which the user can act to release the residue of cutting line.
This solution, albeit solving some problems of the devices
described in the U.S. patents cited above, calls for a particular
configuration of the mowing head, which cannot be produced closed,
and is thus liable to accumulate debris inside it. Furthermore, the
operations of release of the cutting line are far from
convenient.
[0008] Described in U.S. Pat. No. 4,062,115 is a grass-cutting
device with a mowing head to which lengths of cutting line are
engaged via insertion, in pairs of adjacent holes, of two stretches
of one and the same length of line, which is then blocked via a
body that is screwed within the mowing head. The replacement of the
worn-out lines is a complex and long operation.
[0009] Described in the U.S. Pat. No. 4,199,926 is a mowing head in
which the main body is formed by a disk-like member with a hole for
anchorage to the motor shaft. Approximately radial seats made in
the disk-like body receive the ends of lengths of cutting line that
project radially from the body itself. The lengths are fixed in the
corresponding seats by means of screw members that squeeze the
cutting line within its own seat. The clamping is not particularly
reliable and moreover the operations of replacement of the lengths
of worn-out cutting line are long and complex and call for
purposely designed tools.
[0010] Described in the U.S. Pat. Nos. 4,756,146 and 5,433,006 are
mowing heads in which the lengths of cutting line are anchored by
being inserted within a tortuous path made in the disk-like body of
the mowing head. Also in this case, the insertion of the lengths of
cutting line and their replacement following upon wear is a complex
and long operation.
[0011] Described in the U.S. Pat. No. 4,905A65 is a mowing head in
which individual lengths of cutting line are inserted in pairs of
adjacent holes to assume a U-shaped conformation. Particular
solutions are not envisaged for secure anchorage of the lines to
the mowing head.
[0012] Described in the U.S. Pat. No. 5,303,476 is a mowing head in
which a single length of cutting line is anchored in a diametral
position to project with its own ends in diametrally opposite
points of the mowing head. An elastic lever is provided for
engaging the length of cutting line.
[0013] U.S. Pat. No. 5,023,998 describes a mowing head in which
lengths of cutting line are applied in a diametral position to
project with both of its ends from the mowing head itself.
Anchorage is obtained by causing the cutting lines to describe a
tortuous path within the body that forms the mowing head. The
insertion of the cutting lines in this path is a highly complex and
troublesome operation.
SUMMARY OF THE INVENTION
[0014] An object of the present invention is to provide a mowing
head of the type initially mentioned, and in particular of the type
using lengths of cutting line anchored to a body of the mowing
head, which is of simpler and more reliable construction and of
more practical use as compared to known mowing heads.
[0015] Basically, provided according to the invention is a mowing
head comprising: a body which can be engaged to a motor shaft and
defines a peripheral edge; and at least one member for anchorage of
a cutting line, with an elastically loaded eccentric oscillating
element, which co-operates with a contrast surface fixed to the
body of the mowing head for anchoring the cutting line. According
to one embodiment of the invention, the oscillating element
projects from the peripheral edge of the body of the mowing head
with a knurled edge, which forms a gripping surface for causing
oscillation of the oscillating element and release of the cutting
line.
[0016] In an advantageous embodiment of the invention, the
oscillating element is partially surrounded by the contrast
surface, which gradually approaches the oscillating element,
defining an area of insertion and engagement of the cutting line of
variable width, from a mouth of larger dimensions up to a point for
anchorage of the cutting line between the contrast surface and the
oscillating element.
[0017] In a practical embodiment of the invention, the contrast
surface will define a seat for said oscillating element, which is
open along an elongated slit on the perimetral surface of the body
of the mowing head, the oscillating element projecting from said
elongated slit in an off-center position. The cutting line is fed
between one end of the slit and the oscillating element and is
blocked approximately at the opposite end of said elongated
slit.
[0018] In a practical embodiment, the knurled edge forms an
engagement surface for engaging the cutting line, the oscillating
element being set so that said knurled edge pinches the cutting
line against the contrast surface fixed to the body of the mowing
head. The centrifugal force acting on the cutting line when the
mowing head is in rotation tends to increase the pressure exerted
by the oscillating element against said contrast surface.
[0019] According to an advantageous embodiment of the invention,
the conformation of the members for anchorage of the cutting line
is such that, in a position where the cutting line is mounted and
anchored to the mowing head, during rotation said cutting line is
wound around the oscillating element for an angle greater than
180.degree.. Advantageously, the oscillating element can form a
rest for the cutting line during rotation of the mowing head.
[0020] Preferably, the eccentric oscillating element has a circular
cross section and is supported about an axis of oscillation that is
eccentric with respect to the center of the circular cross
section.
[0021] In a practical embodiment, the contrast surface with which
the oscillating element co-operates for clamping the cutting line
has a concave curvilinear development, for example approximately in
the shape of a spiral, and delimits a seat for housing said
oscillating element, said seat being open on the peripheral edge of
the body of the mowing head.
[0022] In a practical embodiment, the concave curvilinear surface
defines, along with the perimetral edge of the oscillating element,
a channel for inserting and guiding the cutting line, said channel
having a decreasing cross section, with a mouth of larger
dimensions on the peripheral edge and an area with a smaller cross
section, in which the cutting line is elastically gripped between
the oscillating element and said concave curvilinear surface.
[0023] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In the drawings:
[0025] FIG. 1 is an exploded perspective view of a mowing head
according to the invention;
[0026] FIG. 2 is a side view of the mowing head assembled, with the
lengths of cutting line anchored to the body of the mowing
head;
[0027] FIG. 3 is a perspective view of the mowing head of FIG.
2;
[0028] FIG. 4A is a cross sectional view according to the plane of
trace IV-IV of FIG. 2 of the mowing head without the cutting
lines;
[0029] FIG. 4B is a cross sectional view according to the plane of
trace IV-IV of FIG. 2 of the mowing head with the cutting lines
inserted; and
[0030] FIG. 5 is a cross-sectional view similar to the cross
section of FIG. 4, illustrated in which is the configuration that
the cutting lines assume when the mowing head is in rotation about
its own axis.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] In a possible embodiment, the mowing head, as a whole
designated by 1, comprises a body 3, which is formed by two
disk-like portions designated by 3A and 3B, respectively. The two
disk-like portions 3A, 3B are coupled together along a plane of
coupling of trace IV-IV (FIG. 2), orthogonal to the axis A-A of
rotation of the mowing head.
[0032] Once coupled together, the two disk-like portions 3A, 3B
define a body that is substantially closed except for two
tangential slits 5 made along the peripheral, i.e., perimetral,
edge 3C of the body 3 of the mowing head. Furthermore, the body 3
formed by the coupling of the portions 3A, 3B has a central hole
3D, which is co-axial to the axis of rotation A-A of the mowing
head. This through hole enables anchorage of the mowing head 1 to a
rotating hub or shaft of a brush cutter or other machinery in two
different positions, which are rotated through 180.degree. with
respect to one another, about an axis orthogonal to the rotation
axis A-A (i.e., with the portion 3A or the portion 3B of the body 3
facing the motor shaft alternatively).
[0033] The two disk-like portions 3A, 3B can be joined together by
bonding, welding 1 with screw means (not illustrated), or in any
other suitable way (herein not represented for reasons of
simplicity). The mutual coupling of the two disk-like portions 3A,
3B can be irreversible, given that (as will be clarified in what
follows) normal use of the mowing head does not require uncoupling
of the two disk-like portions 3A, 3B forming the body 3.
[0034] In the bottom disk-like portion 3B (in the drawing) are two
seats 7 for housing corresponding anchorage members for anchoring
lengths of cutting line. The seats 7 are delimited, not only by the
approximately substantially plane surface 7A made in the disk-like
portion 3B, but also by a curvilinear surface 7B, which is
orthogonal to the surface 7A and has an approximately spiral
development (see FIGS. 4A, 4B and 5). On top, each seat 7 is
delimited by the bottom surface of the disk-like portion 3A, which
can be planar.
[0035] Inserted within each of the two seats 7 is a corresponding
anchorage member, as a whole designated by 9, the components of
which are illustrated in isolation in the exploded view of FIG.
1.
[0036] More in particular, each anchorage member 9 comprises an
eccentric oscillating element 11, of substantially circular cross
section, mounted in the corresponding seat 7. Said eccentric
element 11 can oscillate about the axis of a pin 13, inserted in a
through hole 11A of the element 11. Each pin 13 is inserted in a
hole (which may be blind) 15, made in the surface 7A of the
corresponding seat 7. A corresponding blind hole is made also in
the top disk-like portion 3A, so that each of the two pins 13 is
engaged in two opposed and coaxial blind holes in the portions 3A
and 3B of the body 3 of the mowing head 1.
[0037] The hole 15 is sized in such a way as to be able to receive,
in addition to the pin 13, also an elastic member made in the form
of a helical spring 17. The line forming the helical spring 17 has
appendages 17A and 17B. The appendage 17 A is engaged in the
appropriately shaped cavity constituted by the hole 15, whilst the
appendage 17B has a bent end 17C that is engaged in a corresponding
hole (not illustrated) made on the bottom face of the corresponding
eccentric oscillating element 11. With this arrangement, when the
member 9 is assembled, the helical spring 17 loads the eccentric
oscillating element 11 in a resting position, from which the
element itself can be made to oscillate, torsionally deforming the
helical spring 17.
[0038] As may be noted in FIG. 1, provided on a part of the
perimetral development of each of the elements 11 is a knurling 11Z
for the purposes that will be clarified hereinafter.
[0039] The eccentric oscillating elements 11 are mounted (see in
particular FIGS. 4A, 4B and 5) in the respective seats 7 in such a
way as to project through the respective slit 5 with at least one
portion of the respective knurling 11Z. It is possible to act on
this knurled part of the edge of each eccentric oscillating element
11 to bring about an oscillation of the eccentric oscillating
element 11 for the purpose of releasing the cutting line and
enabling its replacement in the event of wear.
[0040] As may be noted in particular in FIGS. 4A, 4B and 5, in each
of the seats 7 the surface 7B with approximately spiral-shaped
development defines, together with the circular edge of the
respective eccentric oscillating element 11, a channel with a cross
section progressively decreasing from a mouth that is located on
the perimeter of the body 3 of the mowing head 1 at the slit 5 up
to a restriction at a rounded-off edge 7.times. with which the
curved surface 7B terminates. The rounded-off edge 7X is located
basically on the circular perimetral edge 3C of the body 3. The
eccentric oscillating element 11 of each anchorage member 9 is
elastically loaded against the respective rounded-off edge 7C or in
any case towards a position in which it is located at a distance
from said edge smaller than the diameter of the cutting line F.
[0041] Insertion and anchorage of the cutting line F to the mowing
head 1 presented herein is obtained as described here below (see in
particular FIGS. 4A, 4B). Inserted in each of the two seats 7 is
the first end F.sub.A of a length of cutting line F. Insertion is
made through the mouth of the channel with variable cross section
defined by the surface 7B and by the perimetral edge of the
respective eccentric oscillating element 11. The cutting line is
conveniently guided towards the area with smaller cross section of
this channel, sliding on the curved surface 7B and wedging between
the knurled portion 7Z of the edge of the eccentric oscillating
element 11 and the rounded-off terminal edge 7X of the curved
surface 7B, as may be noted in FIG. 4B, where the two lengths F of
cutting line have been completely inserted and anchored in the
mowing head.
[0042] To remove the lengths of cutting line F, for example if
these are excessively worn or broken, it is sufficient to act from
outside the mowing head on the knurled portion 1Z projecting from
the mowing head itself, through the slit 5 of the body 3 to bring
about an oscillation according to the arrow f11 (FIG. 4B) about the
axis of the pin 13 of the corresponding eccentric oscillating
element 11. This movement of oscillation releases the end F.sub.A
of the cutting line F and enables convenient extraction and
subsequent replacement thereof with a new length of cutting
line.
[0043] When the mowing head 1 is made to rotate in the direction
indicated by the arrow f in FIG. 5, the centrifugal force tends to
extend the lengths of cutting line F radially. This pulling action,
thanks to the fact that the lengths of line are wound through a
wide angle (in a possible embodiment, said angle being wider than
180.degree.) around the respective eccentric oscillating elements
11, means that said elements are forced into the gripping position;
i.e., they are tendentially made to oscillate in a direction
opposite to the direction indicated by the arrow fl 1 in FIG. 4B.
This guarantees a secure retention of each of the lengths of
cutting line F during rotation of the mowing head 1. The force
exerted by the vegetation that is cut by the lines F during
rotation of the mowing head causes, on the other hand, a curving of
the cutting lines F, as illustrated in FIG. 5. By so curving, the
cutting lines F rest on the circular edge of the respective
oscillating elements 11, which consequently form a rest with ample
curvature for the lines themselves, so reducing the risk of
breakage due to the mechanical stresses exerted by the vegetation
or by possible obstacles, such as sharp edges of flower beds,
stones, clods of earth or the like, on the cutting lines
themselves.
[0044] Thanks to the fact that the mowing head can be fitted on the
motor shaft in two distinct positions, the direction of rotation f
of the mowing head itself will once again be the one indicated in
FIG. 5, irrespective of the direction of rotation of the motor
shaft. Purposely provided indications on the two faces of the
mowing head can be useful to the user for mounting the mowing head
always in the correct way according to the direction of rotation
(clockwise or counterclockwise) of the motor shaft of the device on
which the mowing head itself is installed.
[0045] While specific embodiments of the invention have been shown
and described in detail to illustrate the application of the
principles of the invention, it will be understood that the
invention may be embodied otherwise without departing from such
principles.
* * * * *