hinge (0,0)
COG
grip
grip · open
door mount area
frame mount area
calculated gas spring
Scroll to zoom · drag empty board to pan · click an image to select its layer
Line drawn: 0px on image
Reset the whole board? This removes both photos and any calculated result, and puts every point and polygon back to the default starting layout.
Gas spring calculation
Not calculated yet — the chart shows the door without gas springs.
▬ grip force
▬ grip force while closing
▮▮ target
Positive = pull to open · negative = pull to close · zero-crossing = balance angle (spring alone holds the door)
Positive = pull to open · negative = pull to close · zero-crossing = balance angle (spring alone holds the door)
Door layer
Hinge setno
Calibratedno
Mirroredno
Opening angle0.0°
COG
Grip
Grip · open
Mount polygon0 pts
Frame layer
Hinge setno
Calibratedno
Mirroredno
Mount polygon0 pts
Please note
This tool gives a first estimate, not a certified design. Always check the chosen spring against the supplier's datasheet and test it before final installation.
- Force depends on length (progression): compressed (F2) = (1 + progression) × extended rating (F1), modelled as an isothermal gas. Progression rises with stroke: .
- Seal friction: the spring pushes N less while extending and as much more while being compressed (per spring, adjustable).
- End-of-stroke damping and temperature effects are not modelled.
- At least mm of stroke is kept unused as a margin, and a stroke is preferably at least % used. The rated stroke is chosen near 40% of the extended length.
- Standard series used (typical values; exact ranges and lengths differ per supplier):
Eye = fitting length added at each end beyond the tube and rod (installation length of the eye / ball socket).
Tips
Scroll to zoom and middle-click-drag (or hold Space and drag, or use two fingers) to pan — these work in every tool, including while calibrating. Drag a mount-polygon point to move it, and shift-click or ctrl-click it to remove it — works both in the normal Pan/zoom/drag mode and in Draw mount polygon mode (which is only needed for adding new points). In Calibrate mode, click two points a known distance apart — a line follows your cursor, then enter the real distance in the panel that appears. Save writes the whole board (including photos) to a file; Load brings it back.