I understand what you are saying, but I believe your description is
flawed in one area. Please see note below.
Thanks,
Pat
E Scanlon wrote:
>Pat:
>
>I know that it can seem illogical, and you're both right and wrong.
>
>The ARM itself will continue to rotate about the motor shaft at the same speed,
>distance, angle etc and there for it would seem that the wipers should not be
>affected by a change in where the arm gets connected to the motor.
>
>However, remember that when the arm connects to the WIPER LINKAGE now you are
>taking
>circular motion and transferring it 900 via another straight rod in order to
>convert
>it to clock and counter clock wise movement or forward and back. If you look
>at the
>old Steam Locomotives and check out the main steam cylinder connection to the
>big
>driving wheel, you'll note that for the locomotive to move forward, the rod
>from the
>cylinder must PUSH along the lower portion of the rotation of the large wheel,
>conversely it should PULL on the upper portion if it does this backwards the
>locomotive will go in REVERSE. Well the same thing happens with the wipers.
>When in
>the proper parked position (at the bottom edge of the windshield) the FIRST
>thing
>that they should do is LIFT off the bottom. The rod connecting the motor to
>the
>wiper must first PUSH for the wipers to lift. If the linkage is 1800 offset
>on the
>motor, it's first action will be to PULL, which will cause the wiper arms to
>wipe the
>cowl.
>
>
While the linkage will require that the motor must push it to start with, it
will only wipe the cowl if you extend the linkage to the point where the
rotational position of the wiper pivot is the same as it was with the motor arm
in its current poistion. By NOT extending the linkage, but just installing the
arm 180 deg. out, it is the same as turning off the key with the wipers
running, and the blades down against the cowl If you do this, when you turn the
key on again the wipers do not move down, they move up, stil, the linkage will
have to push.
Just installing the arm in an other-than-how-it-is-now orientation can not
cause the arm that is attached to it to move any different that it is now,
except for the phasing of the movement of the arm in relation to the motor
shaft position. The circle is the same,and the arm length and geometry is the
same, so the arm movement will be the same. The pivot arm is the same, so the
pivot rotation will be the same, so the wiper arm movement will be the same.
All will be the same,just at a different phase relationship to the MOTOR SHAFT,
but at the same relationship to the motor arm.
This is fun!
Peace,
Pat
>If you choose to do a field test, then please remove the wiper arms and
>replace them
>with bits of masking tape so that you can still observe the rotation without
>damaging
>your hood.
>
>If you'd like, I'll post a sketch for it on www.ClassicFairlady.com.
>
>
>Pat Horne wrote:
>
>
>
>>Enrique,
>>
>>I don't see how changing the orientation of the arm in relation to the
>>motor shaft can cause any problems. The end of the arm will circumscribe
>>the same circle no matter the orientation of the arm to the motor
>>shaft. The only difference will be that the arm will stop in a different
>>place.
>>
>>Peace,
>>Pat
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