Note: Descriptions are shown in the official language in which they were submitted.
CUTTING TOOL WITH BLADE AND
HANDLE OPENING CONTROL MECHANISM
BACKGROUND OF THE INVENTION
I. Field of the Invention,
[0001] The present invention relates generally to improvements
in
cutting tools and more particularly pertains to new and improved hand operated
tools for pruning vegetation.
2. Description of Related Art.
[0002] Hand operated cutting tools that have a first and second
cutting element and handles, that operate like a pair of scissors, with the
blades
bypassing each other, for cutting vegetation, are widely used. These bypass
pruning tools utilize a spring between the handles so that the handles are
pressed
together against the force of the spring. When the handles are released, the
force of the spring causes the blades and handles to open to a maximum opening
angle. Adjustment mechanisms for such bypass cutting tools have been devised
to allow the user to adjust the maximum opening angle of the handle and the
blades. Most of these adjustment mechanisms are not compact, requiring
significant space on the cutting tool. The design of these mechanisms usually
require a complicated arrangement of gears and levers.
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[0003] The present invention overcomes the complexity and size
limitation of prior art adjustment mechanisms.
SUMMARY OF THE INVENTION
[0004] A bypass cutting tool having a manual dial adjustment
for
varying the degree of blade and handle opening to accommodate the hands of a
user. A rotary drum dial uses a nautilus cam with a shaft cam follower to
allow
adjustment on a continuous range of blade and handle openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Many of the attendant advantages of this invention will
be
readily appreciated as the same becomes better understood by reference to the
following detailed description considered in conjunction with the accompanying
drawings in which like reference numerals designate like parts throughout the
figures thereof and wherein:
[0006] Figure 1 is a side perspective of a preferred embodiment
of
the invention at a minimum opening;
[0007] Figure 2 is a side perspective of a preferred embodiment
of
the invention at a maximum opening;
[0008] Figure 3 is an assembly drawing of the preferred
embodiment of the invention;
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[0009] Figure 4 is a magnified perspective of the opening
adjustment mechanism at a minimum opening;
[0010] Figure 5 is a magnified perspective of the opening
adjustment mechanism at a maximum opening;
[0011] Figure 6 is an exploded assembly of the opening
adjustment
mechanism used in the preferred embodiment;
[0012] Figure 7 is a plan front view of the opening adjustment
mechanism;
[0013] Figure 8 is a plan top view of the opening adjustment
mechanism;
[0014] Figure 9 is a plan bottom view of the opening adjustment
mechanism;
[0015] Figure 10 is a cross section opening adjustment
mechanism
of Figure 7 taken along line A-A;
[0016] Figure 11 is a plan side view of the cam follower of the
present invention;
[0017] Figure 12 is a magnified perspective of the opening
adjusting
mechanism and locking mechanism of the preferred embodiment; and
[0018] Figure 13 is a side perspective of the locking shaft
used in
the locking mechanism of Figure 12.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The opening control mechanism of the present
invention is
illustrated in connection with a bypass pruner 11 shown in Figures 1 and 2,
although it may be utilized on other hand operated cutting tools as well. The
bypass lopper 11 of Figures 1 and 2 has a blade 15 attached to a handle 13 and
a
hook 19 attached to a handle 17. The two blades rotate about a pivot axis 20.
A
spiral spring 21 attached to the handles is biased to move the handles 13 and
17
apart. The distance that the blades 15 and 19 are opened by the spring 21 is
controlled by an opening control mechanism 23 mounted to the handles of the
= bypass pruner 11.
[0020] Figure 1 illustrates the bypass pruner 11 with the
opening
control mechanism 23 adjusted to provide a minimal opening 25 of the blades
15 and 19 and the handles 13 and 17. Figure 2 illustrates the opening control
= mechanism 23 adjusted to allow for maximum opening 27 of the blades 15
and
19 and the handles 17 and 13. An opening control mechanism 23 in the form of
a drum dial is adjustable over a range of openings by rotating the drum dial.
[0021] Figure 3 is an assembly drawing that illustrates
the major
components of the opening control mechanism as associated with a cutting
blade 15 and a hook blade 19. Cutting blade 15 is attached to a handle 13 by
way of a blade pivot head 39. FIook blade 19 is attached to handle 17 by way
of
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a hook pivot head 37 which complements the shape of blade pivot head 39.
Blade pivot head 39 has an aperture 40 which aligns with aperture 42 in hook
pivot head 37. A pivot bolt 41 passes through apertures 40 and 42 and is
fastened on the other side of hook pivot head 37 by a nut 43. The blades 15
and
19 rotate about the shaft of bolt 41. The spring mechanism 21 is attached to
complementary positions on the handles 13 and 17.
[0022] A frame 31 attached to the hook blade assembly below its
hook pivot head 37 receives the drum dial control mechanism 23 which will
rotate about its rotary shaft 24 fastened within the frame 31. A cover 29 fits
over the drum dial control mechanism 23 once it is placed within frame 31 to
hold it in place, in a manner that will withstand the environmental impacts
the
tool normally experiences in use. A cam follower 35 attaches to a cam (not
shown) in a manner which will be explained hereinafter, to be activated by the
cam in the drum dial control mechanism 23 to control the degree of opening of
blades 15 and 19.
[0023] Figures 4 and 5 illustrate interaction between the cam
follower 35 and a nautilus cam 49 attached to the drum dial control mechanism
23 and a cam follower travel ridge 47, formed into the blade head 39. Figures
4
and 5 show the position of the cam follower 35 in association with the
nautilus
cam 49. The position of the cam follower 35 and its interaction with the
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follower travel ridge 47 on the blade head 49 illustrated in Figure 4 shows
the
minimum opening setting for the control mechanism 23. Figure 5 shows the
positions of the cam follower 35 and the follower travel ridge 47 for the
maximum opening.
[0024] Referring now to Figure 6, the drum dial control
mechanism
23 is shown as having three major components. A drum dial 55 with a grooved
interior 56 and numerical markings on its exterior. Fitting within the drum
dial
is a nautilus cam 49 which has a spiral cam surface 51 mounted on one end of a
cylinder. A plurality of ridges 53 are formed on the outside surface of the
cam
cylinder 49. These ridges engage with the grooves 56 on the inside of the drum
dial 55. The result being that the cam 49 rotates in unison with rotation of
drum
dial 55.
[0025] A hub 57 fits into the interior of drum dial 55 at the
other
end of the drum dial. It is fixedly attached to the frame 31 below the hook
rotating head 37 of the hook blade 19 (Figure 3) by arms 63. The hub 57 has
fingers 59 that interact with the grooves 56 in the interior of the hub dial
55,
thereby providing a detent feedback when the drum dial 55 is rotated. The hub
57 also has a stop ridge 61 which interacts with a stop 62 (Figure 10) on the
cam
49.
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[0026] Figures 7, 8, 9 and 10 illustrate the structure of the
drum
control mechanism 23 in more detail. Figure 7 is a front plan view of the drum
control mechanism which shows the nautilus cam surface 51 mounted in drum
dial 23 at one end and the hub 57 mounted in drum dial 23 at the other end.
Figure 8 shows a top view of the cam 49 as mounted in the of drum dial 55 with
the ridges 53 on cam 49 aligning with and locking into the grooves 56 in the
interior of drum dial 55. Rotation of drum dial 55 will rotate the cam 49
causing the nautilus cam surface 51 to rotate around its axis of rotation 24.
[0027] Figure 9 shows the bottom view of the hub 57 mounted in
the interior of drum dial 55 to rotate with drum dial 55. Arms 63 on the hub
57
attach to the frame 31 on hook blade 19.
[0028] Figure 10 is a cross section of the drum dial control
mechanism 23 taken along lines AA of Figure 7. The cross section shows the
cam 49 with its nautilus cam surface 51 at one end of the cylinder body
connected to the interior of drum dial 55. At the opposite end, the hub 57 has
attachment arms 63 which attach to the frame 31 (Figure 3) of the hook blade
assembly. The hub 57 rotates freely within the drum dial 55. The stop ridge 61
on the hub 57 interacts with a stop 62 on the cylinder end of the cam 49.
These
two stops define the minimum and maximum opening of the blades,
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[0029] Figure 11 shows a preferred cam follower 35. Cam
follower
35 has a forward section 69 and a rearward section 65 with a groove 71 formed
into the forward section 69 to create a leading wall 68 and a trailing wall
67.
The groove 71 is sized to receive the nautilus cam surface ridge 51 (Figure
8).
As a result of the rotation of cam 49 about its axis of rotation 24, the cam
follower 35 will move laterally forward or backward tracking the spiral cam
surface ridge 51, depending on the direction of rotation of the drum dial. The
position of minimum and maximum blade opening illustrated in Figures 4 and 5
also show the location of the cam follower 35 at these openings. At these
positions the maximum opening position cam follower 35 is in a rearward
position, thereby allowing the blade 15 to open to its maximum opening. In the
minimum opening position the cam follower 35, as shown in Figure 4, is at its
most forward position, thereby preventing blade 15 from opening any further
than indicated.
[0030] The cutting tool of the preferred embodiment also has a
blade lock 45 as shown in Figure 12. The blade lock 45 has a shaft 75 riding
in
a groove on the handle 13 of the cutting blade 15. As the knob of the blade
lock
45 is moved forward, the shaft 75, and specifically its leading edge 79 moves
into an aperture 77 in the hook blade rotation head 37, thereby preventing
rotation of the cutting blade 15 with respect to the hook 19.
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[0031]
Figure 13 illustrates the locking shaft 75 preferably as a
structure have an upstanding arm 81 which attaches to the blade lock knob 45
and a shaft with a leading end 79 and trailing end 83.
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