Revolutionizing Elevator Door Systems

Introducing modern linear door operators

by L.J. Blaiotta

Elevator door systems are critical to passenger safety, operational efficiency and compliance with stringent industry codes. As the president of Columbia Elevator, a sister company to U.S. Door Equipment Corp. (USDE), I’m thrilled to share how our joint efforts are reshaping the U.S. market with innovative door operating equipment.

The Role of Door Operators in Elevator Systems

Elevator door operators, mounted on the elevator cabin, perform the essential function of opening and closing car and landing doors at each floor. With a car-door clutch, door operators ensure proper engagement with landing door equipment — pick-up rollers and interlocks — to unlock landing doors and synchronize their movement with car doors. Safety interlocks, whether for car or landing doors, maintain the integrity of the electrical safety chain, preventing elevator movement unless all doors are securely closed and locked.

Traditional systems, while reliable, rely on older mechanical principles. The “harmonic” system, for instance, uses a pendulum-like door to link arms to control motion. This design necessitates precise manual adjustments to perfect door motion — an approach that can lead to inefficiencies and safety concerns.

The USDE “Robusta” and “Premium-NA” Linear Door Operators

Rather than using classic harmonics to control door motion, USDE offers two modern linear door operators designed for different commercial elevator market needs: Robusta and Premium-NA.

Robusta is tailored for the modernization market, fitting seamlessly into legacy equipment spaces previously designed for harmonic systems. Its design allows for straightforward replacement in existing installations, maintaining compatibility with older configurations while introducing the benefits of advanced linear operator technology. Robusta is ideal for retrofitting elevators without requiring significant structural changes, making it a versatile and cost-effective choice.

Premium-NA, on the other hand, is engineered for the new construction market. This streamlined door operating solution eliminates the need for additional space and equipment historically required by harmonic systems, such as door link arms, clutches and pick-up rollers. By relocating the clutch and pick-up rollers to the hanger track instead of the back of the doors, Premium-NA reduces the space between the back of the car door and the back of the landing door to just the running clearance. This innovation enables architects and designers to minimize the space allocated for elevator shaftways, maximizing rentable floor area in buildings.

The design of Premium-NA also eliminates the need for a back skin on both landing and car doors, which historically served as the mounting surface for harmonic equipment. This “single-skin” door construction significantly reduces door mass, allowing for faster door-closing speeds while remaining within the kinetic energy limits set by safety codes. This reduction in door mass is particularly advantageous in high-rise construction, where faster door operation directly impacts elevator flight times between floors, reducing passenger wait times.

USDE’s Premium-NA door equipment is also fully compatible with Columbia’s PE4 entrance systems, allowing for seamless integration with advanced architectural designs. This includes specialized landing configurations such as PE4 transoms in lobbies or decorative cladding at select floors, combined with standard and cost-effective complete Premium-NA entrances at typical floors. Like Robusta, Premium-NA also features an intelligent door controller that uses a closed feedback loop to optimize performance at each landing while ensuring full compliance with safety regulations.

The Elevantis Platform: A Shared Intellectual Property Initiative

The Columbia/USDE joint venture is built on a shared intellectual property platform called Elevantis. This collaborative framework enables both companies to pool their expertise and innovations, creating cutting-edge solutions in elevator door systems. By leveraging Elevantis, Columbia and USDE ensure their technologies remain at the forefront of the industry, offering reliability, safety and performance for modernization and new construction projects.

Introducing DoorLink: A Revolution in Door Controller Technology

Through our shared IP platform, Elevantis, we are excited to announce that all new Premium and Robusta door operators will be delivered with the innovative Elevantis “DoorLink” door drive starting in summer 2025. DoorLink provides elevator mechanics with unparalleled control over door operator behavior, with full parameter manipulation via a Bluetooth interface, revolutionizing how adjustments are made.

Gone are the days of climbing above the car to manually adjust dip switches, potentiometer dials or plug in a programming tool. With DoorLink, all adjustments are made wirelessly from a smartphone, allowing the mechanic to stand safely inside the cab or in the landing corridor. This vantage point ensures a clear view of both car and landing doors as they operate in unison, simplifying troubleshooting and fine-tuning.

DoorLink is also fully compatible with both discrete and CAN protocols and can drive both asynchronous and permanent magnet motors via a power supply that accepts inputs ranging from 110 V AC to 230 V AC, offering the ultimate flexibility for elevator door system integration.

Not only was DoorLink developed to advance our European and U.S.-fabricated new products, leaving older technologies behind, but a downsized DoorLink dongle version has also been created to be backward-compatible with our previous two generations of door equipment (variable voltage frequency 5 and VVF5+). This ensures that existing installations can benefit from modern control capabilities without requiring a complete system overhaul.

Once plugged into an older door drive, the dongle allows mechanics to utilize the same Bluetooth-enabled proximity setup via their smartphones. While it offers a reduced set of parameter manipulations compared to full DoorLink technology in new door controllers, it still provides a significant upgrade over traditional programming tools, enhancing convenience and safety.

Bringing Innovation to Market

Since forming our joint venture with USDE in May 2022, we’ve focused on delivering advanced solutions to both modernization and new installation markets. Robusta stands out not only for its technical superiority but also for its compatibility with Columbia’s architectural elevator products, including cabs, entrances and doors.

Premium-NA, with its innovative design, represents a leap forward for new construction projects, offering architects and developers a powerful tool to optimize building layouts and reduce construction costs while enhancing elevator performance.

By combining USDE’s engineering expertise with Columbia’s market reach and integration capabilities, we’re empowering building owners, facility managers and elevator contractors with robust, code-compliant solutions that prioritize safety, efficiency and seamless integration.

The Future of Elevator Door Systems

Modern elevator systems must meet increasing demands for safety, energy efficiency and passenger comfort. Innovations like the Robusta and Premium-NA linear door operators, fitted with the latest DoorLink motion control technology, exemplify how technology can solve longstanding challenges while meeting the needs of today’s market.

As we look to the future, Columbia Elevator and USDE remain committed to driving advancements in elevator door technology. Whether for modernization or new installations, our goal is to continue delivering solutions that enhance safety, efficiency and performance.