// Connects the joint to the world instead of another rigidbody
hingeJoint.connectedBody = null;

// Connects the joint to another body
var otherBody : Rigidbody;
hingeJoint.connectedBody = otherBody;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public Rigidbody otherBody;
void Awake() {
hingeJoint.connectedBody = null;
hingeJoint.connectedBody = otherBody;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public otherBody as Rigidbody

def Awake():
hingeJoint.connectedBody = null
hingeJoint.connectedBody = otherBody