Control devices

Claim 1

IN COMBINATION: A CASING COMPRISING A BODY MEMBER, A REMOVABLE FRONT COVER FOR SAID BODY MEMBER, AND A TOP COVER FOR SAID BODY MEMBER, SAID BODY MEMBER HAVING A VERTICAL RECTANGULAR REAR WALL WITH VERTICAL SIDE EDGES, A SUBSTANTIALLY RECTANGULAR SIDE WALL OF A SUBSTANTIALLY LESSER HEIGHT THAN SAID BODY MEMBER REAR WALL ATTACHED TO EACH OF SAID BODY MEMBER REAR WALL SIDE EDGES AND PROJECTING PERPENDICULARLY FORWARDLY FROM SUCH REAR WALL WITH ITS LOWER END IN THE SAME HORIZONTAL PLANE AS THE BOTTOM OF THE REAR WALL AND A NARROW HORIZONTALLY ELONGATED VERTICAL FRONT WALL SECURED TO THE FRONT EDGES OF THE SIDE WALLS WITH ITS LOWER EDGE IN THE SAME PLANE AS THE PLANE DEFINED BY THE BOTTOM EDGES OF THE AFOREMENTIONED REAR AND SIDE WALLS, THE TOP EDGE OF THE FRONT WALL BEING SPACED FROM THE TOP EDGES OF THE SAID SIDE WALLS A MAJOR PORTION OF THE DISTANCE FROM THE TOP TO THE BOTTOM OF THE SIDE WALL, SAID SIDE WALLS EACH BEING PROVIDED AT ITS FRONT WITH AN OUTWARDLY OPENING RABBET, SAID FRONT COVER COMPRISING A SUBSTANTIALLY RECTANGULAR VERTICAL WALL OF THE SAME HORIZONTAL WIDTH AS THE BODY MEMBER REAR WALL AND HAVING A HEIGHT SUBSTANTIALLY EQUAL TO THE DIFFERENCE IN HEIGHTS OF THE BODY MEMBER FRONT AND REAR WALLS, A RECTANGULAR SIDE WALL OF THE SAME HEIGHT AS THE COVER FRONT WALL ATTACHED TO EACH VERTICAL EDGE OF SAID FRONT WALL AND PROJECTING PERPENDICULARLY REARWARDLY THEREFROM WITH ITS TOP AND BOTTOM EDGES LYING IN THE SAME PLANES AS THE TOP AND BOTTOM EDGES RESPECTIVELY OF SAID FRONT WALL, A REARWARDLY EXTENDING RECTANGULAR VERTICAL PLATE-LIKE ARM EXTENDING FROM EACH COVER SIDE WALL ADJACENT ITS TOP, SUCH ARM BEING OF THE SAME HORIZONTAL LENGTH AS THE HORIZONTAL LENGTH OF THE BODY MEMBER SIDE WALLS, AND HAVING AN OUTWARDLY EXTENDING CYLINDRICAL PROJECTION LOCATED AT THE UPPER REAR END THERE-