Electromagnetic Brakes Let Hospital Rooms Go Ergonomic

July 24, 2008
An electromagnetic brake and specialized power supply give medical professionals better access to their patients.

Edited by Jessica Shapiro

Hill-Rom’s Latitude patient-bed care-arm system safely delivers gas, data, and electricity to the patient-care arena and makes bed placement more flexible.

The Latitude system is a flooranchored, cantilevered arm that lets medical staff position utilities, accessories, and the patient bed in the most logical location. The system has accessory tracks for attaching IV holders, monitors, and baskets. As many as nine medical gas connections, 16 electrical connections, and four data connections are available. An optional telescoping arm can extend up to 64 in.

All hospital rooms, particularly those in critical-care areas like ICUs, need provisions for utilities and accessories. A headwall system forces hospitals to place one end of the bed against the wall. That blocks access to the patient’s head. Ceiling- mounted systems provide additional flexibility, but can require expensive structural reinforcements to the building and leave patients with the uncomfortable image of a mechanical arm hanging over them.

The hydraulic or pneumatic brakes used to hold ceiling-mounted systems in place call for another house utility line or a noisy in-room compressor. These add to facility costs and risk leaks and failures.

Danaher Motion worked with Hill- Rom to design two power-off springset electromagnetic brakes for the Latitude system. The 30 lb-in. BRP-23 and 160 lb-in. BRP-30 brakes hold the arms and utility panels at their ends, steady the setup when accessories are attached or removed, and withstand the weight of a patient who may lean on the arms for support.

Electromagnetic brakes provide a quieter patient experience and cut expenses by eliminating pneumatic and hydraulic systems. To further improve affordability while maintaining performance, Hill- Rom requested a smaller brake. Danaher paired a large-diameter gear with a small pinion gear that lets a smaller brake hold the same arm load.

Within the brake, springs hold a shaft attached to the pinion gear in place by friction. When electric power is applied, an electromagnet compresses springs and permits free rotation of the gear. Any interruption in electrical power releases the springs to engage the brake.

Danaher suggested a pickand- hold power supply would eke more torque out of a smaller brake. The standard 80 lb-in. capacity of the bigger brake was boosted to 160 lb-in. using a Hill- Rom-designed 90-Vdc power source. The source kicks up the voltage to 180 Vdc for 20 msec at power-on. The initial power jolt lets the magnet compress the springs and free the pinion gear. The voltage drop after the initial release protects the brake from burnout while keeping friction on the pinion low enough for smooth operation.

With the brake off, the arm and accessory panels can be pivoted with about 15 lb of force. “The brake had specific force requirements that are not standard for a brake in this application,” said Steve Schindel, director of Operations for Patient Environment at Hill-Rom.

Make Contact

Danaher Motion
(716) 531-7119

(812) 934-7777


The Hill-Rom Latitude system improves caregiver access to the patient while supporting all necessary utilities and accessories. A handle on each arm contains brake-control switches that let users position the unit with 15 lb of force.


The brake redesign let the BRP-23 brake provide adequate torque to hold the small pinion gear in place when power is off. Power application frees both gears to turn smoothly.

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