HandController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class HandController : MonoBehaviour {
    public Animator anim;

	// Use this for initialization
	void Start () {
        anim = GetComponent<Animator>();
    }

    // Update is called once per frame
    void Update () {

        AnimatorStateInfo currentState = anim.GetCurrentAnimatorStateInfo(0);
        float playbackTime = currentState.normalizedTime; // % 1;
        float rate = 0f;

        if(currentState.IsName("Normal")) {
            rate = 0f;
        }

        if (currentState.IsName("Grab_001")) {

            if (playbackTime > 1.0f) rate = 0.0f;
            else {
                rate = 1.0f - playbackTime;
            }
        }

        if (currentState.IsName("Grab_002")) {
            if (playbackTime > 1.0f) rate = 0.0f;
            else {
                rate = 1.0f - playbackTime;
            }
        }

        if (Input.GetMouseButtonDown(0)) {
            anim.Play("Grab_001", -1, rate);
        }

        if (Input.GetMouseButtonUp(0)){
            anim.Play("Grab_002", -1, rate);
        }

	}
}