Use this joint slide GameObjects by maintaining the position of two points on a configurable line that extends to infinity. Those two points can be two Rigidbody2D components, or a Rigidbody2D component and a fixed position in the world (by setting Connected Rigidbody to None).
The joint applies a linear force to both connected Rigidbody objects to keep them on the line. It also has a simulated linear motor that applies linear force to move the Rigidbody GameObjects along the line. You can turn the motor off or on. Although the line is infinite, you can specify just a segment of the line that you want to use, using the Translation Limits option.
This joint has three simultaneous constraints. All are optional:
You can use this joint to construct physical objects that need to react as if they are connected together on a line. For example:
SliderJoint2D