Note: Descriptions are shown in the official language in which they were submitted.
CA 02340295 2001-03-08
ADJUSTABLE THROTTLE STOP COLLAR
Field of the Invention
This invention relates to the field of safety devices for hand control
throttles, and in
particular, to a ring or collar for adjustable control of the range of motion
of a manually actuated
throttle lever.
Background of the Invention
As documented in United States patent No. 4,570,593 which issued February 18,
198b to Take et al for a Throttle Safety Device, it is known in the prior art
to lock-out the use of a
throttle trigger so as to prevent irregular operation due to the operator
inadvertently touching and
moving the throttle trigger. Thus as taught by Take et al a prior art throttle
trigger lock-out device
includes a coil spring to resiliently urge a locking member into an operative
position. What is
neither taught nor suggested, and what it is an object of the present
invention to provide, is
spirally, or otherwise eccentrically or irregularly-shaped collar which allows
the incremental
adjustment of the available range of motion of a throttle trigger or lever.
The device provides for
incremental adjustment rather than the lock-out of Take et al in which the
throttle trigger is either
2 0 entirely locked-out to prohibit any range of motion, or entirely unlocked
to allow entirely free
range of motion.
Summary of the Invention
2 5 The adjustable throttle stop collar of the present invention for use in
cooperation
with a manually-operated throttle lever includes a resilient ring defining a
cylindrical ring cavity
therethrough. The ring cavity is sized for snug sliding fitment over a
handlebar handgrip of a
personal recreational craft such as a snowmobile or personal watercraft. The
ring has an outer
surface eccentrically, such as spirally, disposed relative to the cylindrical
cavity. The ring is sized
CA 02340295 2001-03-08
to fit between the throttle lever and the handlebar in a path of the throttle
lever when depressed by
a user so as to selectively obstruct and limit a range of motion of the
throttle lever when rotated
between a closed-throttle idle position and an open throttle position. In one
embodiment of the
invention, the outer surface of the ring is formed as a spiral extending
radially around the outer
surface of the ring between a minimum ring height position, wherein a ring
height between the
cylindrical cavity and the outer surface of the ring is a minimum, and a
maximum ring height
position wherein the ring height is a maximum. The maximum ring height
position is radially
spaced from the minimum ring height position around the outer surface of the
ring. Where the
spiral is a single spiral and the ring height smoothly increases around the
spiral, the minimum and
maximum ring height positions are adjacent and separated only by a notch.
In one embodiment, not intended to be limiting, the ring has a substantially
uniform
thickness measured perpendicular to the ring height, that is, measured
parallel to the longitudinal
axis of the handle when the ring is mounted on the handle. The thickness may,
although not
necessarily, be generally equal to an average height of the ring, that is, the
dimension of the ring
between the cylindrical cavity and the outer surface. Thus, the maximum ring
height may be
greater than the thickness of the ring, and the minimum ring height may be
less than the thickness
of the ring.
2 0 Brief Description of the Drawings
Figure 1 is, in side perspective view, the throttle stop collar of the present
invention
installed onto a handlebar of a personal recreational vehicle or watercraft.
2 5 Figure 2 is the view of Figure 1 in rear perspective view.
Figure 3 is, in side elevation view, the throttle stop collar of Figure 1.
Figure 4 is the throttle stop collar of Figure 3 in front elevation view.
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Detailed Description of Embodiments of the Invention
There are on the market today personal recreational vehicles and watercraft
such as
personal watercraft for example sold under the trademark Sea-Doo, and
snowmobiles such as sold
under the trademark Ski-Doo which employ thumb-operated throttle levers or
triggers to control
and regulate engine speed. Collectively referred to herein as craft, these
craft may be relatively
powerful and capable of rapid acceleration, which in the hands of an
inexperienced user may be
potentially dangerous given the environment in which these craft are operated.
Thus it would be desirable to have a simple-to-use and inexpensive means of
selectively adjusting the available range of motion of the thumb operated
lever or trigger so as to
tailor the amount of available acceleration to a specific user. Thus a more
inexperienced or young
user of such personal craft will have available to them only such levels of
mild acceleration
suitable for training. It is desirable, and an object of the present invention
to provide, that as the
user gains more experience or becomes more physically able with age, that the
available
acceleration may be increased by allowing incrementally an increased range of
motion of the
thumb operated throttle lever or trigger.
2 0 Thus as seen in Figures 1-4, in one preferred embodiment of the present
invention,
an eccentric collar 10 is provided for mounting onto, or adjacent a hand grip
12 on a handle bar 14
so as to be disposed between thumb operated throttle lever 16 and either
handlebar 14 or hand grip
12. Throttle lever 16 is operated by the thumb of a user (shown in dotted
outline) pivoting throttle
lever 16 in direction A about axis B against the resilient return biasing
force acting on the lever as
2 5 well known in the art.
In conventional operation, the user accelerates the personal craft by holding
handgrip 12 in the palm of the hand while simultaneously manually depressing
throttle lever 16 in
direction A. Depressing throttle lever 16 in direction A rotates the throttle
lever about axis of
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rotation B on pins or shaft 18. Manual operation is illustrated as use of the
user's thumb, but this
is not intended to be limiting as manual operation is intended to include
operaxion by any digit.
Collar 10 is made of material such that collar 10 is pliable, flexible, and
resilient
without hysteresis so as to return to its non-deformed state once throttle
pressure from the throttle
lever is released. Further, collar 10 or at least its inner surface may have a
tackiness, for example
if it is made of a polymer material, so as to enhance a friction fit on the
hand grip or handle bar.
Collar 10 is slipped over handgrip 12 and, even though a snug friction fit
thereover,
collar 10 because of its resilient composition may be slid, for example by an
oscillatory corkscrew
motion, along handgrip 12 into a position so as to obstruct the full range of
motion of the throttle
lever when rotated in direction A. The available range of motion for rotation
of throttle lever 16 is
therefore dictated by the size of the obstruction presented by collar 10 and,
in particular, by the
height "h" of collar 10, where height "h" is the distance along a radial line
perpendicular to handle
bar axis C between inner surface 10a and outer surface lOb of collar 10.
Surface 10a is
cylindrical. Surface lOb when viewed in side elevation as seen in Figure 3,
that is, in a plane
perpendicular to axis C when collar 10 is in use as seen in Figures 1 and 2,
forms a spiral relative
to surface 10a so that height h', where surface l Ob is closest to surface
10a, is significantly less
than height h" where surface l Ob is the greatest distance from surface 10a.
Without intending to be limiting, the spiral formed by surface lOb need not
conform to one particular form of spiral, for example, a logarithmic or equi-
angular spiral wherein
angle 8 (the angle between the tangent to the curve and radial line r where
the two intersect)
remains constant as radial line r sweeps out the entire arc as height h
increases gradually from
2 5 height h' to height h". In alternative embodiments, surface 1 Ob does not
necessarily have to be a
gradually increasing spiral surface relative to center "c" but may undulate or
otherwise provide for
irregular heights h so long as rotation of collar 10 in direction D allows for
collar 10 to be
angularly preset so as to adjust the amount of the obstruction, that is, the
particular height h of
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collar 10 which is deliberately advanced so as to obstruct the trajectory of
trigger lever 16 as it is
rotated in direction A about axis B.
Thus in the embodiment illustrated, for a novice or young user of the personal
craft
where it is desirable to allow only a small amount of acceleration, collar 10
is rotated so as to
position peak l Ob' so as to minimize the available range of rotational motion
of trigger lever 16.
This would normally mean rotating peak l Ob' to a position beneath where
trigger lever 16 would
first contact hand grip 12 or handlebar 14 were it not for the presence of
collar 10.
Conversely, where the user is more experienced or older, peak l Ob' is rotated
out of
the way so as to, for example, position the portion of surface lOb
corresponding to height h'
beneath trigger lever 16 so as to allow an increased range of motion and
commensurate increased
acceleration available to the user.
In between these two extremes, rotation of collar 10 allows for incremental
adjustment of the available range of motion and commensurate acceleration to a
user. The snug
frictional fit of resilient collar 10 onto handgrip 12 allows for presetting
of the rotational
orientation of collar 10 and for retaining collar 10 in that spatial
orientation during use. The snug
frictional fit of collar 10 resists the vibration of the handlebar which might
cause collar 10 to rotate
2 0 out of its desired position.
In preferred embodiment, thickness "t" as seen in Figure 4 may be 0.50 inches.
In
that preferred embodiment, without intending to be limiting, the diameter of
the cylindrical cavity
defined by surface 10a may be 1.125 inches. Dimension d, may be approximately
1.94 inches,
2 5 dimension d2 may be approximately 0.87 inches, dimension d3 may be
approximately 2.1 inches
and dimension d4 may be approximately 2.3 inches. In this manner, collar 10
will snugly fit on to
at least some of the handgrips 12 of which applicant is aware and will provide
for the eccentric
relationship between surfaces 10a and lOb which provide the aforementioned
advantages. A
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person skilled in the art would know to make the required adj ustments to the
aforesaid dimensions
to accommodate different sized handgrips 12.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention
without departing from the spirit or scope thereof. Accordingly, the scope of
the invention is to be
construed in accordance with the substance defined by the following claims.
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