Sprag gear

Russ from MN · Sep 1, 2021

I'm fixing up our Toro walk behind mower, it's over 20 years old, but starts the first pull, so it's getting a new transmission, the old one is getting really noisy. I have never seen gears like this, but what a unique idea, and after 20 years, almost no wear! There is a woodruff key with a spring under it in the shaft, allowing the gear to rotate freely over the key when necessary. Waiting for 2 more bearings, then I will put it together.

Mule Meat · Sep 2, 2021

Lawnboys design.
The spring keeps the pinion gear tight against the drive clutch and friction disc. The rocking key catches the inside slots in the pinion gear when power is applied to the axle. When you release the drive handle (helps to push the mower forward a few feet) the rocker releases and allows the mower to freewheel until the axle is engaged again.

Note: The rocking keys are designed to be used on one side only. You will have a left and a right and they will not work if installed on the wrong side..

Russ from MN · Sep 3, 2021

The new bearings came yesterday, so I got it all put together, works well. The gears are marked R & L on each gear, so they can go
on either side, they just have to be turned the right way.

Sprag gear

Russ from MN

Well-known Member

Mule Meat

Well-known Member

Russ from MN

Well-known Member

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