Patented Technology Offers Design Upgrade, Licensing Opportunity for RF and EMI Shielded Door Industry

patent photo

Radio frequency (RF) and electromagnetic (EMI) shielded doors are used across multiple industries, yet the basic closing mechanism of the doors has been largely unchanged since the 1970s. Now, one patent-holder is offering a licensing opportunity to the RF and EMI shielded door industry that makes these bulky, difficult doors easy to open and close while providing a myriad of other benefits.

Stephen Rust recently developed United States patent #8,925,251, which is entitled “Constant Force Spring Perimeter Seal for an Electromagnetic Shielded Door.” The mechanism design provides a fresh upgrade to the closing apparatus that has been used for over three decades. Current RF and EMI shielded doors still use this old mechanism that has a number of disadvantages. The traditional knife edge mechanism works by scraping between two rows of spring fingers and uses nearly a dozen moving parts, leading to a higher rate of wear and tear and expensive maintenance calls. This complicated design leads to higher manufacturing and freight costs, a high volume of warranty claims and safety liabilities, and customer satisfaction dilemmas.

The new design works to reverse cost, convenience, liability, and customer satisfaction issues by implementing a constant force flat torsion spring that gently coils and uncoils when the shielded door is open and closed. This new technology provides constant metal-to-metal contact, which is necessary for effective RF shielding, while offering an operator-friendly experience. The new design eliminates difficult handles and latching mechanisms, as well as the dilemma of latching failures and operators becoming stranded inside shielded rooms. Rust’s new patent provides a way for affected industries to reduce manufacturing and freight costs, warranty claims, arm and shoulder injuries, the need for excessive force when closing heavy shielded doors, and door alignment problems. The design upgrade can easily be applied to new construction or retrofit situations, providing a longer useful life, lighter door options, and secure shielding. Testing proved that the new design effectively eliminates broadband disturbances. Shielding effectiveness of 100 dB at 1 GHz is expected.

Stephen Rust is now providing licensing opportunities for the “Constant Force Spring Perimeter Seal for an Electromagnetic Shielded Door” patent. Interested parties can learn more by emailing

Photo by tanakawho