Title of Invention	A CYCLIC NOISE SUPPRESSING ROTARY LINK FOR THE WINDSHIELD WIPER UNIT OF AN AUTOMOBILE
Abstract	-A cyclic suppreosinff rotary link for the windshield wiper unit of an automobile said rotary link comprising a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of said unit, said rotary link giving rise to a first gefttrlfugal force during rotary thereof charadorised in that the body of the said rotary, link, beyond the said pivot, is balanced, statically or dynamically, to produce a second force, substahtially equal and opposite to the first centrifugal force, and thus nullify the affect of th« first centrifugal force.

Title of Invention

A CYCLIC NOISE SUPPRESSING ROTARY LINK FOR THE WINDSHIELD WIPER UNIT OF AN AUTOMOBILE

Abstract

-A cyclic suppreosinff rotary link for the windshield wiper unit of an automobile said rotary link comprising a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of said unit, said rotary link giving rise to a first gefttrlfugal force during rotary thereof charadorised in that the body of the said rotary, link, beyond the said pivot, is balanced, statically or dynamically, to produce a second force, substahtially equal and opposite to the first centrifugal force, and thus nullify the affect of th« first centrifugal force.

Full Text	This invention relates to a cyclic noise suppressing rotary link for the windshield wiper unit of an automobile. A windshield wiper motor is a shoal permanent magnet motor, whose output shaft is suitably connected to a linkage which is, in turn, connected to the wiper arm and blade. Normally wiper motors are capable of operation in several speeds. The speed is chosen depending upon the intensity of rain. The wiper unit comprises a worm formed integrally with the armature shafts—a worm gear (usually made of plastic) meshing with the said worm; an output shaft integral with the worm gear, the shaft being supported on ball bearings. During the operation of the wiper, a cyclic noise is created, which is augmented by the rotary movement of the rotary link, causing an imbalance force produced by centrifugal force, due to the fact that the mass centre of the rotary link is situated at a definite radial distance from the centre-line of the said output shaft. This unbalanced force is capable of displacing the output shaft about its axis to the extent of clearance between the bush and the shaft. The tilting of the shaft decreases the centre distance whenever the link is dispositional 180 degrees opposite to the meshing point of the gear. This increases cyclic noise level, particularly, at high speeds. This invention therefore proposes a rotary Link which suppresses such cyclic noise to an appreciable extent. The various features of this invention will be apparent from the following further description. The cyclic noise suppressing rotary link for the windshield wiper unit of an automobile, according to this invention, comprises a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of said unit, said rotary link giving rise to a first centrifugal force during rotary involvement thereof, characterised in, that the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force, and thus nullify the effect of the first centrifugal force. This invention will now be described with reference to the accompanying drawings which illustrate, by way of example two of various possible embodiments of the rotary link proposed herein, wherein Fig.l illustrates the known wiper unit Fig,2 illustrates another view of the known wiper unit eig.a and 4 illustrate the known rotary link in plan and in elevation Fig.5 illustrates the weighted (balanced) rotary link according to an embodiment of this invention and Fig.6 illustrates the magnetically balanced rotary link according to another embodiment of this invention. Figs. 1 and 2 illustrate the known wiper unit comprising the motor Q, worm W, worm wheel Y, output shaft S and rotary link R. The motor G drives the worm W which in turn drives the worm wheel Y and thence the shaft S. The shaft S imparts the rotary movement to the rotary 1ink R which is transmitted through a linkage to the wiper arm and blade. On the shaft S the rotary link is mounted, the shaft being thus a pivot P for the rotary link which executes an angular to and fro movement along with the said shaft. The rotary link E comprises a first end El for connection to the wiper assembly of the said unit and a second end E2 for being pivotably mounted on the output shaft S, as aforesaid. Normally, during rotary movement of the rotary link R, a centrifugal force is set up to result in cyclic noise, as explained earlier. According to this invention, however, the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force and thus nullify the effect of the first centrifugal force. The body of the rotary link B, beyond the pivot P, is extended, the weight of the extension B being sufficient to produce the second centrifugal force. If necessary, the extension B can be weighted, by attaching Heights separately thereto, to achieve the same result. Another of possible ways of achieving the same result is by placing a magnet Ml near the second end E2 of the rotary link and fixing another magnet M2 to the body of the rotary link beyond the pivot P whereby during rotary movement of the said rotary link, the said magnets exert a force of attraction with respect to each other, to set up the second centrifugal force aforesaid. Alternatively, the magnet M2 is dispensed with and the body of the rotary link, beyond the said pivot P is magnetized at J whereby during rotary movement of the said rotary link, the magnetic force of attraction exerted, sets up the second centrifugal force aforesaid. The terms and expressions herein are of description and not of limitation there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, but it Is understood that various other embodiments of the rotary link proposed herein are possible without departing from the scope and ambit of this invention- We Claim: l.A cyclic noise suppressing rotary link for the windshield wiper unit of an automobile» said rotary link comprising a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of said unit, said rotary link giving rise to a first centrifugal force during rotary movement thereof characterised in that the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force. and thus nullify the effect of the first centrifugal force. 2.A rotary link as claimed in Claim 1 wherein the body of the rotary link> beyond the pivot, is extended, the weight of the extension being sufficient to produce the second centrifugal force. 3.A rotary link as claimed in Claim 2 wherein the extended portion of the body is weighted* 4. A rotary link as claimed in Claim 1 wherein a magnet, is placed near the said second end of the said link and another magnet is fixed to the body of the said link beyond the pivot whereby during rotary movement of the said link, the said magnets exert a force of attraction with respect to each other, to set up the second centrifugal force. 5.A rotary link as claimed in Claim 1 wherein a magnet is placed near the said second end of the said link and the body of the said link, beyond the said pivot is magnetised, whereby during rotary movement of the said link, the magnetic force of attraction exerted sets up the second centrifugal force aforesaid. 6. A cyclic noise suppressing rotary link for the windshield wiper unit of an automobile substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

Full Text

This invention relates to a cyclic noise suppressing rotary link for the windshield wiper unit of an automobile.
A windshield wiper motor is a shoal permanent magnet motor, whose output shaft is suitably connected to a linkage which is, in turn, connected to the wiper arm and blade. Normally wiper motors are capable of operation in several speeds. The speed is chosen depending upon the intensity of rain.
The wiper unit comprises a worm formed integrally with the armature shafts—a worm gear (usually made of plastic) meshing with the said worm; an output shaft integral with the worm gear, the shaft being supported on ball bearings.
During the operation of the wiper, a cyclic noise is created, which is augmented by the rotary movement of the rotary link, causing an imbalance force produced by centrifugal force, due to the fact that the mass centre

of the rotary link is situated at a definite radial distance from the centre-line of the said output shaft. This unbalanced force is capable of displacing the output shaft about its axis to the extent of clearance between the bush and the shaft. The tilting of the shaft decreases the centre distance whenever the link is dispositional 180 degrees opposite to the meshing point of the gear. This increases cyclic noise level, particularly, at high speeds.
This invention therefore proposes a rotary Link which suppresses such cyclic noise to an appreciable extent.
The various features of this invention will be apparent from the following further description.
The cyclic noise suppressing rotary link for the windshield wiper unit of an automobile, according to this invention, comprises a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of

said unit, said rotary link giving rise to a first centrifugal force during rotary involvement thereof, characterised in, that the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force, and thus nullify the effect of the first centrifugal force.
This invention will now be described with reference to the accompanying drawings which illustrate, by way of example two of various possible embodiments of the
rotary link proposed herein, wherein
Fig.l illustrates the known wiper unit
Fig,2 illustrates another view of the known wiper unit
eig.a and 4 illustrate the known rotary link in plan and in elevation

Fig.5 illustrates the weighted (balanced) rotary link according to an embodiment of this invention
and
Fig.6 illustrates the magnetically balanced rotary link according to another embodiment of this invention.
Figs. 1 and 2 illustrate the known wiper unit comprising the motor Q, worm W, worm wheel Y, output shaft S and rotary link R. The motor G drives the worm W which in turn drives the worm wheel Y and thence the shaft S. The shaft S imparts the rotary movement to the rotary 1ink R which is transmitted through a linkage to the wiper arm and blade.
On the shaft S the rotary link is mounted, the shaft being thus a pivot P for the rotary link which executes an angular to and fro movement along with the said shaft.

The rotary link E comprises a first end El for connection to the wiper assembly of the said unit and a second end E2 for being pivotably mounted on the output shaft S, as aforesaid.
Normally, during rotary movement of the rotary link R, a centrifugal force is set up to result in cyclic noise, as explained earlier.
According to this invention, however, the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force and thus nullify the effect of the first centrifugal force.
The body of the rotary link B, beyond the pivot P, is extended, the weight of the extension B being sufficient to produce the second centrifugal force. If necessary, the extension B can be weighted, by

attaching Heights separately thereto, to achieve the same result.
Another of possible ways of achieving the same result is by placing a magnet Ml near the second end E2 of the rotary link and fixing another magnet M2 to the body of the rotary link beyond the pivot P whereby during rotary movement of the said rotary link, the said magnets exert a force of attraction with respect to each other, to set up the second centrifugal force aforesaid.
Alternatively, the magnet M2 is dispensed with and the body of the rotary link, beyond the said pivot P is magnetized at J whereby during rotary movement of the said rotary link, the magnetic force of attraction exerted, sets up the second centrifugal force aforesaid.
The terms and expressions herein are of description and

not of limitation there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, but it Is understood that various other embodiments of the rotary link proposed herein are possible without departing from the scope and ambit of this invention-

We Claim:
l.A cyclic noise suppressing rotary link for the windshield wiper unit of an automobile» said rotary link comprising a first end for connection to the wiper assembly of the said unit and a second end for being pivoted to the output shaft of the drive of said unit, said rotary link giving rise to a first centrifugal force during rotary movement thereof characterised in that the body of the said rotary link, beyond the said pivot, is balanced, statically or dynamically, to produce a second centrifugal force, substantially equal and opposite to the first centrifugal force. and thus nullify the effect of the first centrifugal force.
2.A rotary link as claimed in Claim 1 wherein the body of the rotary link> beyond the pivot, is extended, the weight of the extension being sufficient to produce the second centrifugal force.

3.A rotary link as claimed in Claim 2 wherein the extended portion of the body is weighted*
4. A rotary link as claimed in Claim 1 wherein a magnet, is placed near the said second end of the said link and another magnet is fixed to the body of the said link beyond the pivot whereby during rotary movement of the said link, the said magnets exert a force of attraction with respect to each other, to set up the second centrifugal force.
5.A rotary link as claimed in Claim 1 wherein a magnet is placed near the said second end of the said link and the body of the said link, beyond the said pivot is magnetised, whereby during rotary movement of the said link, the magnetic force of attraction exerted sets up the second centrifugal force aforesaid.

6. A cyclic noise suppressing rotary link for the windshield wiper unit of an automobile substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

Documents:

099-mas-1997 abstract.pdf

099-mas-1997 claims.pdf

099-mas-1997 correspondence-others.pdf

099-mas-1997 correspondence-po.pdf

099-mas-1997 description (complete).pdf

099-mas-1997 drawings.pdf

099-mas-1997 form-1.pdf

099-mas-1997 form-26.pdf

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Patent Number

220614

Indian Patent Application Number

99/MAS/1997

PG Journal Number

29/2008

Publication Date

18-Jul-2008

Grant Date

29-May-2008

Date of Filing

21-Jan-1997

Name of Patentee

LUCAS TVS LIMITED

Applicant Address

Inventors:

#	Inventor's Name	Inventor's Address
1	REMACHANDRAN VENKATARAMANAN
2	KRISHNAVILASAM RAGHAVAN ANANDAKUMARAN NAIR

PCT International Classification Number

B60S 1/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA