Abstract: A mounting assembly for detachable connection to a metal forming machine, such as a punch press or the like, including a pair of bracket members pivotally mounted for swingable movement about a vertical axis toward and away from one another with one of the bracket members mounting an electrical energy source and the other mounting a receiver member for generating a protective light-curtain therebetween. Pivot members are operatively associated with each of the bracket members for enabling the same to pivot about a vertical axis, and selectively adjustable locking members for locking either of the bracket members in fixed relation to one another.