| The gears worked smoothly, to the minor accompaniment of the ratchet clicking and the links passing over the drive sprocket. |
| This results from excessive snakiness of the chain due to sprocket and roller misalignment or uneven roller wear. |
| If the bar, chain and nose sprocket are not properly lubricated, these components will surely fail prematurely. |
| The drive sprocket is at the rear and the idler at the front, and there are no track return rollers. |
| The small sprocket wheel in turn is coupled to the ratchet wheel, which allows only the uni-directional rotation of the ratchet sleeve shaft. |
| Then, in some unexplained way, the sprocket chain tore loose and managed to wrap itself about the boy's neck, strangling him. |
