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How Moment is Calculated
When choosing between Soft Close, Free Stop, and Lift-Assist stays, use the door or lid moment as a reference. The moment refers to the force that attempts to rotate an object around a given point. If the door or lid moment matches the supported moment of the stay, then the stay is suitable for use. ■ Moment Formulae
Horizontal distance from rotation centre to centre of gravity (m)
Door/lid moment (N· m)
Door/lid weight (kg)
9.80665
Moment is calculated with the “horizontal distance” to the centre of gravity; because its value changes according to the opening angle, the formula for maximum moment is as below.
Largest value of horizontal distance from rotation centre to centre of gravity (m)
Door/lid max. moment (N·m)
Door/lid weight (kg)
9.80665
Side Panel
Centre of gravity position
Door
Rotation axis centre
Horizontal distance from rotation axis centre to centre of gravity position
■ Calculating the Centre of Gravity Position
Centre of gravity position
Door
L 2
Centre of gravity position
L
For complex shapes like L-shapes, break them down into simple shapes as shown above. Calculate the centre of gravity for each part, then find the total centre of gravity by combining them. The same method applies when attaching a mirror to a wooden panel. The “SASUGA-kun” selection tool can be used to assist with this calculation.
For a door or lid in a uniform position, the centre of gravity is at the midpoint. The distance from the rotation axis centre to the centre of gravity is L/2. Note: This applies when the door or lid is thin.
■ Relationship between Usable Stays and Door Moment
For Torque Stays (Free-Stop): Usable when the stay torque exceeds the door’s maximum moment.
For Damper Stays (Soft Motion): Usable when the door’s maximum moment is within the range of moments supported by the stay.
sds1d04. eps
Stay torque
Door max. moment
Door max. moment
Stay supported moment range
Opening Angle
Opening Angle
Notes: ·The door moment indicated for each product is based on the mounting dimensions provided in the catalogue. ·Torque refers to the force acting around the rotation axis, and moment refers to the force causing the door or lid to rotate around a given point.
No.500 Catalogue
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