Note: Descriptions are shown in the official language in which they were submitted.
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VIBRATION REDUCING LINK FOR VIBRATING SCREED
FIELD OF THE INVENTION
[0001] The present invention relates to a vibration dampening handlebar link.
More
specifically, the present invention is concerned with a vibration reducing
link for vibrating
screed.
BACKGROUND OF THE INVENTION
[0002] Known in the art, there are vibrating screeds including, for instance,
an
elongated blade extending horizontally and transversally at lower ends of a
pair of handles
adapted to be hand held and operated for displacing the screed over a concrete
surface. A
motor is provided above the blade and between the handles and has its shaft
extending
vertically downwards from the motor to the blade and is connected thereat such
that, with a
counterweight or a cam-like arrangement, it imparts oscillatory movement to
the blade of
high frequency but low amplitude.
[0003] Generally, such devices are guided and controlled by a pair of
handlebars to
be gripped by an operator to permit easy and constant correction of the level
of the concrete
with minimum effort. For example, U.S. Pat. No. 6,296,467 (Rouillard)
discloses a
handlebar with textured rubber grip members attached thereto. Furthermore, the
screed has
adjustable handles including a main elongated handle member. Each handle has a
first
element mounted to a proximal end of the main handle member. The handle has
second
and third elements capable of relative rotatable displacement and capable of
being secured
in a desired relative position thereof with a grip member being mounted to the
third element
such that the grip member may be swiveled at least partly around an axis of
the second
element.
[0004] However, the operation of such devices usually occurs over many hours
during which period vibrations from the oscillatory movement of the blade will
be transferred
to the operator through the handles means leading to increased operator
fatigue.
[0005] While the prior art teaches of vibration isolators which act to reduce
the
vibration produced by a vibration exciter mechanism, such vibration reducing
isolators are
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located near the vibration exciter mechanism itself and away from the operator
handles.
[0006] The Applicant has discovered that even with such vibrating reducing
isolators
located near the vibration exciter mechanism, there are still substantial
remaining oscillatory
movements transferred to the operator. There is therefore a need for a
solution to this
problem of vibrations felt by the user when grasping handlebar grip members of
vibrating
screed.
SUMMARY OF THE INVENTION
More specifically, in accordance with the present invention, there is provided
vibrating
screed comprising:
a surfacing blade;
a vibration-causing assembly in communication with the surfacing blade;
a steering assembly in communication with the surfacing blade, the steering
assembly comprising a handle assembly;
a grip member in communication with the handle assembly; and
a vibration reducing link disposed between the grip member and the handle
assembly;
wherein when the vibration-causing assembly imparts a vibratory motion to the
blade and
the handle assembly, the vibration reducing link dampens the vibratory motion
transmitted
between the handle assembly and the grip member.
[0007] Preferably, the reducing link comprises: a first member in
communication with
the handle assembly; a vibration reducing coupling disposed circumferentially
about the first
member; a second member in communication with the grip, the second member
receiving
the vibration reducing coupling and the first tubular member; and a clamp for
securing the
first tubular members and the vibration reducing coupling within the second
tubular
members when received therein; wherein the vibration reducing coupling dampens
vibration
transmitted between the first and second members.
[0008] Preferably, the vibration reducing coupling is disposed
circumferentially within
the second member, the first member received within the vibration reducing
coupling and
the second member.
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[0009] Preferably, the first member and the vibration reducing coupling are
rotatable
within the second member.
[0010] Preferably, the vibration reducing coupling has a non-elastomeric layer
disposed circumferentially about the vibration reducing coupling.
[0011] Preferably, the vibration reducing link includes a coupling made of
elastomeric
material such as vulcanized rubber to couple handlebar members in order to
dampen
vibration and shock.
[0012] Preferably, the first member in substantially perpendicular in
communication to
the handle assembly, the second member is substantially perpendicular in
communication
to the first member.
[0013] Preferably, the clamp is circumferentially disposed about the second
member.
[0014] Advantageously, compared to prior art screed, the present invention
localizes
vibration isolators closer to the handles such that the remaining vibrations
not suppressed
by the isolators located closer to the vibration exciter mechanisms are
further and
substantially reduced.
[0015] Another advantage of the present invention over the prior art involves
the
capability of easily retrofitting the vibration reducing link to the handle
assemblies of existing
screeds.
[0016] Other objects, advantages and features of the present invention will
become
more apparent upon reading of the following non-restrictive description of
specific
embodiments thereof, given by way of example only with reference to the
accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the appended drawings:
[0018] Figure 1 is a perspective view of a handlebar assembly for vibrating
screed
incorporating a vibration reducing link used to couple handlebar assembly
elements;
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[0019] Figure 2 is a perspective view of a vibration reducing link for
vibrating screed;
[0020] Figure 3 is a cross-sectional view of the vibration reducing link of
FIG. 2;
[0021] Figure 4 is a longitudinal sectional view of the invention in FIG. 1
wherein the
section plane is indicated by the arrows A-A of FIG. 3;
[0022] Figure 5 is a perspective view of a handlebar element for vibrating
screed;
[0023] Figure 6 is a perspective view of a handlebar assembly for vibrating
screed
demonstrating the relative rotational and longitudinal motions of handlebar
elements.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0024] The present invention is illustrated in further detail by the following
non-limiting
example. FIG. 1 illustrates a vibration reducing link assembly for a vibrating
screed
handlebar means 10 comprising a first element 12, a second element 13 and a
third
element 14, the second element 13 and third element 14 capable of relative
rotatable
displacement and capable of being secured in a desired relative position by
clamping
means '11. A vibration reducing assembly 15 (See FIG. 2) according to a
preferred
embodiment of the present invention dampens vibrations which propagate between
coupled
second element 13 and third elements 14.
[0025] Referring to FIG. 2, the vibration reducing assembly 15 is comprised of
a
vulcanized rubber tubular coupling 16 linking a handlebar element 17 of second
element 13
to a tubular element 18. Vibrations emanating from handlebar element 17 are
reduced as
they propagate outwardly through the vulcanized rubber tubular coupling 16 to
tubular
element 18.
[0026] Now referring to FIG. 3, the vibration reducing assembly 15, having a
vulcanized rubber tubular coupling 16 enclosed by a tubular element 18 and
used to link the
second element 13 to the third element 14, is readily visible. As is apparent
from this figure,
tubular element 18 is isolated from vibrations propagating from handlebar
element 17 by a
vulcanized rubber tubular coupling 16.
[0027] FIG. 4 is a longitudinal sectional view of the invention in FIG. I
wherein the
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section plane is indicated by the arrows A-A of FIG. 3. From this figure, the
configuration of
the vibration reducing link is apparent. Vibrations propagating from handlebar
element 17 to
tubular element 18 are reduced by a vulcanized tubular coupling 16.
[0028] FIG. 5 is a perspective view of the third element 14 of a vibration
reducing link
assembly for vibrating screed handlebar means 10. Second element 13 and third
element
14 are linked together by inserting the vibration reducing assembly 15 into
space 19 of third
element 14 and compressing them together by clamping means 11.
[0029] FIG. 6 is a perspective view of third element 14 of a vibration
reducing link
assembly for vibrating screed handlebar means 10 capable of relative rotatable
displacement and capable of being secured in a desired relative position to
second element
13. The vibration reducing assembly 15 engages space 19 (See FIG. 5) along the
longitudinal axis 21. Once engaged, third element 14 is rotatably displaceable
about the
rotational axis 20 and secured to vibration reducing assembly 15 in space 19
by clamping
means 11.
[0030] In a preferred embodiment of the preferred invention, the use a
vibration
reducing link as part of screed's handle assembly has demonstrated a
substantial reduction
in the remaining vibrations transmitted to the upper sections of the handle
assembly. The
reduction in vibration is as much as 80% when compared to vibration experience
in the
handle assemblies of the prior art which do not have additional vibration
isolators.
[0031] Although the present invention has been described hereinabove by way of
specific embodiments thereof, it can be modified, without departing from the
spirit and
nature of the subject invention. For example, such a vibration reducing link
described herein
could be used whenever vibration dampening is needed for other construction
equipment
such as power trowels, concrete saws, and hand held or walk behind dirt and
asphalt
compactors utilizing handlebar assemblies. Furthermore, applications for such
a vibration
reducing grip may also include any situation where a vibrating handlebar needs
to be
grasped by a user such as is the case, for instance, for power tools,
motorcycles, bicycles,
and lawnmowers.
