Motorised shears prevent RSI

Anyone who has suffered from mouse arm or tennis elbow knows about the painful and persistent condition known as repetitive strain injury (RSI). Even the smallest movement can cause extreme and long-lasting damage to muscles, tendons and nerves if it is repeated thousands of times.

If mouse arm results from operating computers, the equivalent for wine and fruit growers, who must trim countless branches and shoots, is shearing arm. Each hectare in a vineyard may contain between 5000 and 10,000 vines, which means that approximately 100,000 cuts per hectare must be made. Furthermore, even small fruit trees must be trimmed and pruned hundreds of times.

In order to prevent fatigue, manufacturers developed mechanical pruning shears. In the beginning, pneumatic systems were the only mechanical solution. It then became possible to replace compressed air with electrical energy by using lightweight lithium-ion batteries. This allows wine growers to simply go round the corner and move up and down in the rows without limitation. Electric shears are connected to a battery, which is normally fastened onto the wine grower’s belt with a short cable while the electrical motors are integrated into the shear’s handles and apply the necessary force.

With many people now using motorised shears, Italian manufacturer Campagnola decided to develop a pair of shears that simplify the wine grower’s work in every respect. Campagnola’s Pony model is a low-power device that works with a FAULHABER DC micromotor in order to offer high efficiency at a low weight.

“During the cutting season, the operator must often use the shears relentlessly for weeks,” said Patrizio Pellicanò, the technical director at Campagnola. “This means that the operator must hold the device for the entire day and every gram of weight counts.”

The motor is the crucial component, but not only in regards to its weight. As noted by Christian Lucini of FAULHABER MINIMOTOR, who is responsible for the project, “The drive must have high torque while the weight is reduced to a minimum.

“It must also work at high speeds in order to make the cuts as quickly as possible,” Lucini continued. “Due to the start-stop nature of this work, with constant load changes, the shears must also provide force without warming up, while the energy consumption is minimised and the operating time maximised.”

Campagnola carried out a series of tests comparing the drives of different manufacturers based on these criteria. According to Pellicanò, the 2657 CR DC micromotor from FAULHABER “clearly won the comparisons”.

“With just 156 g for the motor, the entire drive system weights 80 g less than other motor gearhead combinations. In addition to this, high efficiency, in combination with low energy consumption, provides a usage duration of 10 h per charge, which corresponds to 20% more battery life in comparison to rival products.”

Said to be one of the lightest pairs of shears on the market, the Pony can perform up to 70 cuts per minute and can be operated both automatically and manually. In automatic mode, the cutting blades fully close as soon as the finger presses the trigger. In manual mode, the cutting blades conform to finger movements, which means the motor reacts precisely and the output power must be adjusted exactly to the movement.

The shears also protect the drive-supporting wires. If wires are detected between the cutting blades, the shears stop cutting automatically. A cutting counter, which records the operating times, makes it possible to monitor the cutting movements in detail and allows the operator to comply with service intervals.

“The devices run constantly when trimming vines and fruit trees, particularly in large companies,” said Pellicanò. “In addition to this constant load, the shears must be able to work for four or five years without any problems. The DC micromotor from FAULHABER has proven itself with its characteristics and high reliability in continuous operation. We have definitely made the right choice here.”