As a manufacturer of fire and rescue vehicles both for the home market and for export, through the MoD, to countries such as Cyprus and the Falkland Islands, Emergency One builds its vehicles to customer specifications. Variations range from water, foam and equipment carriers and small quick response vehicles, to standard pumping appliances and off-road animal/water rescue vehicles.
One such specialist rescue unit (SRU), which is being used by Nottinghamshire Fire and Rescue Service, enables stowage of a vast range of dedicated equipment including a fully-inflated boat for water rescue, positioned on a trailer for quick off-load. When considering systems for deploying the heavy equipment, the company considered proprietary systems, but all presented problems as their design, powered by large pistons, would not allow the inflated trailer-mounted boat to be fully enclosed within the roofed body of the SRU.
With the weight of the towed boat dictating that it had to be deployed via an automatic system, Emergency One set about designing its own compact version to fit into the roof void. Central to this Automatic Boat Gantry System (ABGS) is a robust and corrosion-resistant HepcoMotion Sealed Belt Drive (SBD). The SBD was developed to provide a reliable product for high loads and demanding cycles. It features a sealing method that excludes debris and is available in beam lengths of up to 6m as standard.
In the resultant ABGS design, the SBD is mounted to the floor of the compartment, connected to a tilting beam on which the boat and trailer are stowed. A pivot bar, with stops, arrests the beam at the required height and angle. The mechanism is activated via push buttons on the side of the SRI. When the ‘out’ button is pressed, the SBD begins its travel towards the rear of the vehicle, pushing the tilting beam, boat and trailer out of the back of the body. This movement continues along the full length of the SBD until the boat is fully tilted. After use, the boat and trailer are pulled back onto the vehicle by the SBD to their fully stowed position where automatic air pistons lock the system in place.
This mechanism is driven by a pneumatic rotary motor that is connected to the end of the SBD and for which HepcoMotion provided a dedicated mating face. The overall load that the SBD pulls is around 250kg. However, due to torque at the point where the boat stalls in its fully lowered position, the motor had to be over-specified and regulated to lower the speed of travel to around 3m per second.
“One of the main challenges of this project was indeed determining the tilt and stress points to verify whether the design was viable,” said Lee Dawson of Emergency One. “We also needed to write special computer logic to regulate the air system to ensure smooth and safe deployment.”
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