A snow blower or snow thrower is a machine for removing snow from an area where it is not wanted, such as a driveway, sidewalk, roadway, railroad track, ice rink, runway, or houses. The term "snow thrower" is often used to encompass snow throwers and snow blowers, however, in proper a snow thrower is a machine that uses a single stage to remove or "throw" snow while a snowblower uses two stages to remove or "blow" snow. It can use either electric power, or a gasoline or diesel engine to throw snow to another location or into a truck to be hauled away. This is in contrast with the action of snow plows, which push snow to the front or side (shovels can be similarly used).
Snow throwers range from the very small, capable of removing only a few inches (a few cm) of light snow in an 18 to 20 in (457 to 508 mm) path, to the very large, mounted onto heavy duty winter service vehicles and capable of moving 10-foot (3.05 m) wide, or wider, swaths of heavy snow up to 6 feet (1.83 m) deep. Snow blowers can generally be divided into two classes: single stage and two stage.
 Single-stage and two-stage snow throwers
Single-stage snow throwers use a single high-speed impeller to both move the snow into the machine and force it out of the discharge chute. The impeller is usually in the form of two or more curved plastic paddles that move snow towards the center line of the machine where the discharge chute is located. Single-stage snow throwers usually are light-duty machines. Small electric machines can be picked up manually to chew away deep snow.
In a two-stage machine, two mechanisms move the snow: an auger feeds the snow to a high-speed impeller, which blows the snow out of the machine. Two-stage snow blowers range from small machines of a few horsepower to very large machines powered by diesel engines of over 1000 horsepower (746 kW). The large machines are used for clearing roadways and airport runways, often by throwing the snow into trucks, which haul it away.
Two-stage machines for home use are usually self-propelled, using either large wheels equipped with tire chains or, in some cases, tracks. The auger drive on these machines are usually equipped with a shear pin. If a jam occurs in the auger, this pin will break, averting damage to the auger drive gears. The broken pin must then be replaced before the machine can be used again, generally a relatively simple process.
Snow throwers are usually single-purpose machines, though some have detachable front ends that can be replaced with other implements, such as a rotary tiller.
 Safety issues
The U.S. Consumer Product Safety Commission estimates that each year there are approximately 5,740 snowblower related injuries in the United States which require medical attention. One problem with the design of the snow blower is that snow can build up in the auger, jamming it and stalling the motor. This is complicated by the fact that the auger could deform before applying enough resistance to the motor to turn it off. If the jam is cleared by hand, it is possible for the auger to return to its natural shape suddenly and with great force, possibly injure the user; snow blowers are a leading cause of traumatic hand and finger amputations. The correct procedure is to turn off the engine, disengage the clutch and then clear the jam with a broom handle or other long object.
Most modern machines mitigate this problem by including a safety system known as the "Dead man's switch" (which may be electrical as implied or mechanical in design, such as a lever), to prevent the mechanism from rotating when the operator is not at the controls. In some jurisdictions, this is a mandatory requirement.
In December 2008, a snow blower accident made national headlines in the United States when Joe Sakic, the famous captain of the Colorado Avalanche hockey franchise of the National Hockey League, sustained three broken fingers and tendon damage when he attempted to clear the auger of his snowblower by hand. The team denied reports that Sakic required surgery to reattach one of his fingers. 
Robert Carr Harris of Dalhousie, New Brunswick patented a "Railway Screw Snow Excavator" in 1870. Various other innovations also occurred. However, it is Arthur Sicard (1876–1946) who is generally credited as the inventor of the first practical snow blower. In 1925 Sicard completed his first prototype, based on a concept he described in 1894. He founded Sicard Industries in Sainte-Thérèse, Quebec and by 1927 his vehicles were in use removing snow from the roadways of the town of Outremont, now a borough of Montreal. His company is now a division of SMI-Snowblast, Inc. of Watertown, New York.
 See also
- Mario Theriault, Great Maritme Inventions 1833-1950, Goose Lane Editions, 2001, p. 61
- About Sicard
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