VIBRATION REDUCING LINK FOR VIBRATING SCREED

Abstract

A vibrating screed for surfacing concrete includes a surfacing blade, a vibration-causing assembly, a steering assembly with a handle assembly and a grip member in communication with the hand assembly. A vibration reducing link is disposed between the grip member and the handle assembly so that 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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority, under 35 U.S.C. § 119(e), on U.S. provisional patent application serial No. 61/118,033, filed on Nov. 26, 2008, which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

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

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.

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.

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.

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 located near the vibration exciter mechanism itself and away from the operator handles.

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.

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.

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.

Preferably, the first member and the vibration reducing coupling are rotatable within the second member.

Preferably, the vibration reducing coupling has a non-elastomeric layer disposed circumferentially about the vibration reducing coupling.

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.

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.

Preferably, the clamp is circumferentially disposed about the second member.

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.

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.

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

In the appended drawings:

FIG. 1 is a perspective view of a handlebar assembly for vibrating screed incorporating a vibration reducing link used to couple handlebar assembly elements;

FIG. 2 is a perspective view of a vibration reducing link for vibrating screed;

FIG. 3 is a cross-sectional view of the vibration reducing link of FIG. 2;

FIG. 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;

FIG. 5 is a perspective view of a handlebar element for vibrating screed;

FIG. 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

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.

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.

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.

FIG. 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. 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.

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.

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.

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.

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.

Claims

1. A vibrating screed comprising: wherein when said vibration-causing assembly imparts a vibratory motion to said blade and said handle assembly, said vibration reducing link dampens said vibratory motion transmitted between said handle assembly and said grip member.

a surfacing blade;

a vibration-causing assembly in communication with said surfacing blade;

a steering assembly in communication with said surfacing blade, said steering assembly comprising a handle assembly;

a grip member in communication with said handle assembly; and

a vibration reducing link disposed between said grip member and said handle assembly;

2. The vibrating screed according to claim 1, wherein said vibration reducing link comprises: wherein said vibration reducing coupling dampens vibration transmitted between said first and second members.

a first member in communication with said handle assembly;

a vibration reducing coupling disposed circumferentially about said first member;

a second member in communication with said grip, said second member receiving said vibration reducing coupling and said first tubular member; and

a clamp for securing said first tubular members and said vibration reducing coupling within said second tubular members when received therein;

3. The vibrating screed according to claim 2, wherein said vibration reducing coupling is disposed circumferentially within said second member, said first member received within said vibration reducing coupling and said second member.

4. The vibrating screed according to claim 2, wherein said first and second members are tubular.

5. The vibrating screed according to claim 2, wherein said first member and said vibration reducing coupling are rotatable within said second member.

6. The vibrating screed according to claim 3, wherein said first member is rotatable within said vibration reducing coupling and said second member.

7. The vibrating screed according to claim 2, wherein said vibration reducing coupling has a non-elastomeric layer disposed circumferentially about said vibration reducing coupling.

8. The vibrating screed according to claim 3, wherein said vibration reducing coupling has a non-elastomeric layer disposed circumferentially about said vibration reducing coupling.

9. The vibrating screed according to claim 2, wherein said vibration reducing coupling is made of an elastomeric material.

10. The vibrating screed according to claim 9, wherein said elastomeric material is rubber.

11. The vibrating screed according to claim 2, wherein said first member in substantially perpendicular in communication to said handle assembly, said second member is substantially perpendicular in communication to said first member;

12. The vibrating screed according to claim 2, wherein said clamp is circumferentially disposed about the second member.