238 



HANDBOOK OF MECHANICAL DESIGN 



, - - Snap lever i Compress/on spring ^ / On position of trigger 



1 ~ •■ ■_ 





Fig. 488. — A design of switch similar to that shown in Fig. 486 except that it is a two-pole design and is self- 

 opening when the trigger is released. It is shown here in the "on" position. As soon as the trigger is released, the 

 ■eompression spring opens the switch. 



Toggle type releasing switch handle. Used on 

 old style d.c. reamers, toggle device tor ^ 

 quick make and break 





Fig. 489. — A toggle-type self-opening switch used on old-style direct-current reamers. The tripper is pushed 

 forward until the line of pull of the spring passes the dead center of the link to which it is attached. The spring then 

 pulls the switch closed. Upon releasing the trigger, the mechanism returns to the position shown, the switch snapping 

 open when the toggle spring passes dead center. 



Fig. 490. — A conventional-type switch of old design that is self-opening when the trigger is released but can be 

 held in the closed position by means of a looking pin. Common to all the switches shown in this group of designs, it is 

 not dustproof. 



