Ease of Use
How quickly and easily a trimmer starts means getting to work as soon as you arrive at the jobsite. Manufacturers have designed starting procedures to be quick and intuitive. “We attempt to have starting that is simple with as few steps as possible,” says Marv Mathwig, product manager for power tools at Stihl Inc.
So what does it take to achieve near effortless starting? “Generally, a product that is easy to start contains an electronic ignition and a carburetor primer to reduce the number of pulls on the starter rope,” explains Gary Truman of Shindaiwa. “On larger, higher-cc products, the starter might include a spring-assisted system that reduces the force required to pull over the engine with the starter rope.”
It also goes beyond that. “Easy starting doesn’t necessarily mean easy pulling,” explains Gary Hardee of Husqvarna. “It needs to be intuitive.” Trimmer starting and throttle control, when intuitive, can increase efficiencies and reduce training time. Symbols and the location of controls all lend themselves to intuitive use, making it easy for an employee with little trimmer knowledge to get to work right away. This is especially important in a workforce heavily composed of H-2B workers who speak English as a second language.
The construction and location of controls should also enhance operator comfort. “The starter grip or handle needs to have smooth edges,” explains Hardee. “And the location of the starter rope out of the machine should be in line with the way the operator is going to use it, making it easier to pull.”
The overall weight of the trimmer and the even distribution of that weight can also make it more comfortable to operate, reducing user fatigue. “One of the most crucial factors for the landscaper is the power-to-weight ratio,” says Mathwig. “An operator is using the trimmer all day long for days at a time, so you want as much power as possible—and as little weight as possible. Balanced weight and ergonomic grips make it comfortable for use all day long.”
Shielding hands from the vibration of the machine also reduces operator fatigue. “Being able to isolate hands from the machine reduces the impact of vibrations,” says Hardee. “Many modern trimmers have a handle made of flexible material, or have isolating dampeners on the throttle handle that absorb some of the vibration.”
Power Means Performance
If a worker is comfortable using the unit all day long, it should be powerful enough to withstand the stresses of long use. “How well a unit functions depends on the amount of power it has,” says Mathwig. “Most landscapers are using units anywhere from one to two horsepower.” While there isn’t a huge power requirement needed for routine maintenance, more power is needed for trimming something for the first time.
Using the throttle to quickly increase the speed of the trimmer head increases jobsite efficiency for regular use and on the more challenging jobs. “It’s imperative that the trimmer has a good throttle response,” says Hardee. “The user has to be able to throttle-up very fast. They are going to be walking along, trimming, taking a few steps and then trimming again, up and down on the throttle the entire time. When you are idling and the head is not turning, you want it to immediately start turning when necessary.” The torque should automatically adjust to meet the challenge of the material it is cutting through, speeding up to cut better through the thicker grass.
As most in the power equipment industry are aware, engine emission regulations have continued to change how engines are made. “In October 2008, the Environmental Protection Agency (EPA) issued updated emissions regulations for small spark ignition (SI) engines, which include the handheld engines used on string trimmers,” says John Fischer, who has worked designing engine components and installations, most recently with Iveco Motors/FPT Powertrain. “With these new regulations, there are now evaporative emissions requirements in place which will minimize the amount of raw fuel that can find its way into the atmosphere.”