Pellenc

Pellenc designs, produces and markets tools and machines that are both comfortable and safe for users, making their work easier and increasing their productivity. The manufacturer was having problems with the drive chain of its new electric pruning shears and so it contacted Cetim. “If you want professional pruning shears that are easy to handle and not too burdensome, they should not be too heavy or too bulky; this means smaller reduction gears and motors”, explained Samuel Pierre, Technical Manager. “In addition, they must be sturdy and withstand a wide range of outside temperature variations.” The preliminary analysis of the parts carried out by Cetim, based on calculations and simulations, revealed that an interference phenomenon was the cause of critical tooth wear and meshing impacts, resulting in a high level of noise.

Faster and quieter
The solutions that Cetim proposed to Pellenc involved a new geometry and a new sizing of these high-speed gears (20,000 rpm). Cetim also recommended manufacturing the high-speed gears (20,000 rpm) in a higher accuracy class. The new geometry, which takes into account space requirements has two main advantages: it offers a 5% increase in efficiency while significantly reducing vibrations and noise during operation.
The qualification tests on the prototype yielded convincing results: “The parts are now made of metal rather than plastic, and the precision of the manufacturing class has been improved by 2 or even 3 grades,” stated Samuel Pierre. The transmission is now smoother and quieter and the noise level of the pruning shears has been divided by 4, decreasing from 81 to 74 dB.”

On top of this project, Cetim helped Pellenc’s teams to upgrade their skills in the field of mechanical transmission by acquiring the KissSoft software and the necessary training.