Power Window Project DIY 64-66 TRUCK

[Steve Van Gent]

Originally Posted by Captainfab

I think one of the reasons for the finer toothed sector gear is to slow down the action of the regulator with the given speed of the motor. I'm thinking that if you were to fit a coarser tooth gear on the sector shaft, the window may travel too fast. It might be better to see about changing the driven 'gear'. Of course that is all relative to the speed of a given motor.

I'm not sure that is true. I think the speed of glass is a case of the diameter of the gear (or radius), speed of that gear (I.E. the worm gear inside pitch). In other words, lets take an extreme case-if two separate gears both turn 10RPM, but one gear is 2 inches in diameter, one gear is 12 inches in diameter, the bigger gear will be slower regardless of pitch of teeth or sector...

Another way to look at it; if the gear were unrolled and laid flat, it would have a fixed length (2 * Pi * R). the travel of the sector per one revolution of the gear would be that length, regardless of the pitch.

[Captainfab]

I disagree. Lets assume that the pitch is the same on both the 2" diameter gear, the 12" diameter gear and the driven gear. And lets assume that the driven gear has a diameter of 12". If the 2" diameter gear turns 10 rpm, the driven gear will turn 1.66 rpm. If the 12" diameter gear turns 10 rpm the driven gear will turn 10 rpm.

[urmyboyblue]

Gear pitch (teeth per linear inch of gear) has to do with power transmission. The greater the pitch, the larger the tooth and the more power that can be transmitted. Gear pitch has nothing to do with gear reduction- that is the result of pitch diameters of gears. If gear A has a pitch diameter of 12" and gear B has a pitch diameter of 2", the ratio is 6:1 (A:B). So every time A rotates, B rotates 6 times. Changing the gear pitch of gear B while keeping the pitch diameter the same has no effect on ratio, but it means the teeth won't mesh right. IF you can get them to work together, they will eat each other up quickly.

With two gears of the same pitch, the number of teeth on each gear is directly proportional to the pitch diameter (via the gear pitch). So you can divide the number of teeth on one gear by the number of teeth on the other gear and find the gear ratio. BUT this only works if both have the same gear pitch.

It seems like JC Whitney used to sell a universal bolt on kit for power windows in a car with manual windows. It had a coupler on the lift motor shaft that attached to the stem that the window crank normally attaches to. Don't know if they still make it. The motor mounted to the door panel.

[Steve Van Gent]

Here is another way to look at it; lets say it there was a toothless wheel (had some kind on non-skid on surface for traction) against a shaft that moves linear direction; as the wheel moved, the shaft would move the same distance as the wheel moved (2*pi*r). Teeth pitch is not a factor.