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02.05.2017

BJ worm gearboxes can help the future fire fighters and craftsmen

Students at Aarhus School of Marine and Technical Engineering have just completed a 10-week project, where they were to show their abilities in manufacturing, assembling and troubleshooting. Two of the student groups asked BJ-Gear for worm gearboxes to be used to manufacture their ideas. The two groups made a firefighting robot and a trailer mover respectively.


Firefighting robot to help the fire departments

The fire extinguishing group was inspired by a school room where gas cylinders are installed. In case of fire, these cylinders can overheat and explode and in worst-case scenario firefighters, who are to extinguish the fire, can be injured. Therefore, the decision was to construct a robot that can be remote controlled to drive into a room and splash coolant fluid on any explodable element.

The group found that their engine speed was to be reduced from 5,000 to 120, so the group requested worm gearboxes with gear ratio of 50:1.

Trailer Mover for the craftsman

The Trailer Mover group wanted to make a device to move a trailer at construction sites where the craftsmen's car could not get around. The group had three requirements from the start: The machine had to be able to drive 4 km/h at an elevation of 10% with a trailer weighing a total of 1500 kg.


Emil Nielsen from the group explains: "Our engines drove most optimally at 1500 rotations per minute, and the tire wheels for our chains had a circumference of 31 cm. We therefore calculated a need of reduction of the engine's rotation speed from 1500 rpm to 212 rpm, which corresponded to a gear ratio of approx. 7:1. We also ensured that the torque needed to meet our requirements was lower than the torque we would have after a 7:1 gearing.


Click on the photo to see a demonstration.


The engine's torque was 9.5 Nm, and the torque we got at the end of the gearbox was 66.5 Nm. What needed to start a movement (with a trailer of 1500 kg on a 10% elevation) was 40.5 Nm, and therefore we found, that the gearing would work fine with our engines and tire wheels. We chose to use worm gearboxes to be able to brake on a hill (standing still with a trailer in front of or behind the trailer mover).