A single hinge joint should be applied to a gameobject the fundamental object in unity scenes which can represent characters props scenery cameras waypoints and more.
Unity hinge joint door example.
How to open doors on a hinge like a real door.
More info see in glossary controlled by rigidbody a component that allows a gameobject to be affected by simulated gravity and other forces.
Add a hinge joint and apply a one time force and if the door exceeds a certain angle stop applying the force.
Multiple hinge joints can also be strung together to create a chain.
The main door should be assigned as the connected body so the doggy door s hinge is dependent on the main door s rigidbody.
More info see in glossary the hinge will rotate at the point specified by the anchor property moving around the specified axis property.
A gameobject s functionality is defined by the components attached to it.
Add a joint to each link in the chain and attach the next link as the connected body.
This joint simulate pendulum.
But this joint can be used to do the same.
Playing with the same concept more or less this week experimented some with 2d unity joints i think the issue you are having is identical to one i had yesterday the force you are applying breaks joints for some frames hence that almost spring joint effect make sure the mass and or force applied are not too heavy also maybe increase the chain parts mass makes the joints more solid too.
This joint restricts the movement of a rigid body to follow the movement of the rigid body it is attached to.
In unity you can relate two bodies to transform by parenting one to the other.
Unity 4 6 hinge joint broken in asset bundles.
You do not need to assign a connected body to.
Also this joint is used when you want two connected bodies apart.
Physics hingejoint rigidbody hinge motor joint joints 2d collision door rotation rope anchor spring javascript connectedbody rigidbody2d axis animation c swinging submesh unity 5 hang wheel collider.