Engineering Report

– Whipper Snipper/Lawn Trimmer Essay, Research Paper

Whipper snipper/ Lawn Trimmer No one person or corporation is attributed with creating the lawn trimmer however the original lawn trimmers where developed from1968 to 1970. Prior to 1970, there were no line trimmers, as we know them today. Can you imagine edging sidewalks, driveways, parking lots and shrub beds with hand-held trimmers? Can you imagine how sore your back, arms and legs would be after a long day of pushing a manual edger along seemingly endless sidewalks and driveways? Can you imagine trimming any turf at all without a powered trimmer? Many of us take the advantages the line trimmer gives us for granted.

Line trimmers are one of the most important pieces of equipment in the wide array of landscaping tools. They put an edge on sidewalks, shrub and flowerbeds and parking lots. The time we save by using these tools is something people may take for granted these days. Since the early 1970s (when the first powered line trimmers appeared), the machines have improved with stronger line, more attachments and better engines. This is all in the aid of giving more time and quicker action in the increasingly hectic lifestyles of today.

The basic trimmer works by the engine driving a multi-bearing supported hardened steel shaft housed in an aluminium tube through a centrifugal clutch this shaft is connected to a ?head? that holds a nylon line that spun at high revolutions per minute (RPM). This nylon line then cuts the grass by hitting the blades of grass at high speed, this cause the grass to be severed at the point of impact. Thus trimming the grass.

The first models were petrol powered, as electrical lawn mowing devices had gone out of fashion due to the danger of electrocution after accidentally cutting the power cord. The original petrol powered trimmers where two stroke engines around 28 to 32 cubic centimetres in capacity powered by a mixture of ?super? petrol and oil, today they are much the same with the exception of being powered by unleaded petrol and oil, but becoming more popular is the electric trimmer. A leader in engine technology Honda has taken the latest accomplishment, with Mini 4-Stroke engines. Powered by the only 360′ inclinable (can be turned on any angle and still run properly) 4-stroke engine available today, the new Honda trimmers deliver smooth, dependable power and unsurpassed fuel efficiency. They require no special gas/oil mixtures so there’s no chance for improperly mixed fuels. And they’re remarkably quiet, virtually smokeless and environmentally friendly.

The New 4-Stroke Honda engineThe two-stroke engine cycle produces lager amounts of smoke and noise than four stroke cycles, this is due the fact that there is less time for the fuel/oil mixture to combust completely and the fact that two strokes run at higher engine RPM (revolutions per minute) about 7000 RPM compared with around 4000 RPM of four strokes. This increased Rpm causes greater vibration of the engines cooling fins and in turn more noise. The increased RPM means that more air and fuel is going into the inlet port via the carburettor of the engine which means more induction noise, silencers are used but noise is still high, with all his extra air and fuel going in to the engine extra exhaust gases must come out meaning greater exhaust noise, mufflers do help but a high decibel reading still is present.

A typical 2-stroke trimmer


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