Double Action Piano Hinge

Double action piano hinge offers excellent spring force adjustability for doors of different weights. It uses a built-in cam-type preload mechanism. This mechanism enables continuous adjustment in steps of ten newtons. Tests show that the hinge fits door weights from 25 kilograms to 120 kilograms. Within this range, the bidirectional opening and closing torque deviation stays within ±1.5 newton meters at any set point. The adjustment accuracy reaches 1.2 percent. A six-month tracking study covered one hundred installed doors. The data showed that the centering return force changed by only 0.3 newton meters after 5,000 opening and closing cycles. This change represents a variation of less than 2 percent. In comparison, traditional spring hinges showed a return force drop of over 15 percent under the same usage frequency. This advantage makes the hinge ideal for supermarket free-swing doors and hospital corridor doors. It eliminates the need for frequent spring tension readjustments.

 

 

The hinge also performs well in chemical resistance and fast return response. We immersed the entire hinge in an acid salt spray solution. The solution contained 5 percent sodium chloride and 3 percent glacial acetic acid. We kept the hinge immersed for 300 hours. After drying, we measured the torque values. The results showed that the increase in both forward and reverse operating torque did not exceed 4.1 percent of the initial value. The return times from a 30‑degree opening angle were 0.7 seconds and 0.8 seconds for inward and outward directions. These values were nearly identical to those measured before immersion. We then conducted a cross-cut test according to the GB/T 9286 standard. The coating adhesion reached the highest level of zero. We wiped the surface with acetone fifty times. The coating showed no peeling. For impact resistance, we used a 20‑joule pendulum to strike the door edge repeatedly. After thirty consecutive impacts, the cumulative return angle deviation was only 0.6 degrees. This result proves that the hinge maintains accurate centering and return function even with frequent cart collisions in logistics passages. It ensures reliable automatic closing performance.

 

 

 

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Make tooling according to the confirmed drawing, do the modification if needed while testing.

 

 

 

Make first samples, send them to the customer for approval.

 

 

 

 

Strictly produce the goods as per the drawings and first samples.

Packed well after final inspection and ship to customers.

 

 

Get drawings from customers, or design drawings according to customers' details requests or sample.

Both parties confirm the drawings.

 

 

 

 

Quote and confirm order quantity, specify all the details including trade terms, payment terms, type of package, etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

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