four-bar
A four-bar at 60°, solved
Ground 4, crank 1, coupler 3.5, rocker 3. Every joint position here is the output of a Newton–Raphson solve on the loop-closure equations, converged to 0.0e+0 — not a placement that looked right. Grashof's condition classifies these lengths as a crank rocker, and sweeping the crank through 360° confirms it: 120 of 120 positions assemble. The transmission angle at this instant is 66.9°.
Linkages, solveddraggable: crank anglewide
Where it is used
- A length is a range As built
- The chain that does not close One path to the tool
- Four bars and four pins Linkages
- The easy problem and the hard one change places Several legs, one platform
- The ratio that is not a number Drawn wrongly
- What a coupler point draws The paths points trace
- What decides whether it moves What can move
- Grashof, predicted and then swept Linkages
- Two things called jamming Drawn wrongly
- The four lengths do not matter equally As built
- The mechanism Grübler says cannot move What can move
- The transmission angle Linkages
- What each joint takes away What can move
- Worst case and the square root As built
- Eight ways to hold the same tool One path to the tool
- The return stroke is quicker Linkages
- The wheel is the coupler Machines you have met
- Where a stack-up stops working As built
- The curve the other assembly draws The paths points trace
- How far the crank turns first As built
- The angle that holds the lock Motion that stops
- Grashof is a shape test Linkages
- One test, three mechanisms Motion that stops
- What is still outside As built
- Eight kinds of four-bar Linkages
- The transmission angle has no size More than one input
- A swing and a time ratio Linkages
- Four kinds of slider-crank Linkages
- A parallelogram a micron wrong What can move
- A drag link ahead of a crank-rocker Linkages
- Tolerancing the holes As built
- Three rotations, and four benches Linkages
- A length error is undone by its own size What can move
- Six things a measurement cannot tell you Drawn wrongly
- A quick return that cuts evenly Linkages
- Every change point lies flat What can move
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