The ONSPOT Automatic Tire Chain offers the traction of
a single set of conventional snow chains at the touch of a button,
without having to stop the vehicle.
An
electric switch mounted in the cab provides 12 volts to an air
solenoid mounted on the vehicle's frame rail. Compressed air
to the solenoid is supplied from either the vehicle's onboard
air system or a 12-volt compressed air kit.
When
the dashboard switch is activated the solenoid opens allowing
compressed air to enter the air chamber and lower the chainwheel
so it contacts the inside of the tire. The fiction between the
tire and the rubber-covered chainwheel causes the chainwheel
to rotate, creating enough centrifugal force to flail the chains
out in front of the tire. (The principle of the system is similar
to a small generator driven by a bicycle tire to operate a headlight.)
Six
lengths of chain spaced at 60-degree intervals on the chainwheel
ensure that there are always two chains between the tire and
road surface whether you are accelerating, braking, or are in
a wheel lockup condition. The traction from the chainwheel is
obtained in forward OR reverse.
When
the dashboard switch is turned off, the solenoid exhausts the
air provided to the chain units and return springs in the chambers
bring the chainwheels back to their resting position.

|