CompositesWorld
Issue link: https://cw.epubxp.com/i/450689
CompositesWorld.com 47 Emergency Ergonomics Illustration / Karl Reque Ferno Composites' iN∫X Ambulance Cot › EMT weight-bearing during patient transport is minimized by making each motorized leg set on the cot independently operable. › A two-piece, hollow design allows the legs to accommodate internally the cables and pulleys used in leg extension and retraction. › The SMC wall thickness in each leg is optimized to meet a stringent weight-bearing requirement yet minimize the weight penalty in leg fabrication. Anything that allows them to do their job longer — as iN∫X does — is welcome." Lose weight, please To make the iN∫X vision come to life, however, was another matter. Ferno project engineer Nick Valentino says Ferno's experience was primarily with aluminum, but its engineers soon learned they'd have to change their thinking about not only leg design but mate- rials as well. For the latter, Ferno turned to one of its suppliers, Citadel Plastics (formerly Premix, North Kingsville, OH, US). Called in early, during product development, Citadel representa- tives thought that the application was better suited for composites. Ferno's experience with composites, however, was limited. "It was a new material for us, so we really had to put it through its paces," Valentino says. "But we're really just trying to keep weight down and this [composites] allowed a form and look that we wanted, and it created a part that got rid of a lot of other parts." Citadel was retained to help guide design and engineering decisions. Te resulting leg design clearly ofers aesthetic appeal (see photo, p. 46), but Valentino says that once the decision to use composites had been made, function took precedence. Te challenge, he says, is that all EMS cots must conform to some basic size and shape standards for ambulance compatibility. In addition, a cot must ft into standard-sized elevators and pass through standard-sized doorways. Tat meant Ferno was confned, with the iN∫X, to a fxed shape envelope of 597 mm wide and 2,045 mm long. Terefore, the independently operated legs, when both are closed, must ft within the shape envelope without interfering with each other, and allow sufcient room for mounting actuator motors between each set of legs without interfering with other cot functions. "Leg geometry is more function than form," Valentino notes. "Tey [the legs] must ft into an envelope that is typical of current designs. Te legs must pass through each other, past actuator mounts and clear all bumpers." Roy Bendickson, product development engineer at Citadel, worked closely with Valentino and Ferno on leg design and Cot table extends and lifts (see photo, p. 48) to support patient Motorized legs extend/retract independently Carbon fber/vinyl ester SMC (nominal 25.4-mm fber length) Two-piece, hollow legs (4) accommodate cables and pulleys Wheel-mounting hardware COT SIDE VIEW (maximum operational size window: 2,045 mm by 597 mm) Leg supports (4) also of hollow design Load-bearing capability (each leg) 590 kg 558.8 mm