Correcting slope of equipment compared to preset angle, useful for hedge cutters and drills

摘要

Two conducting tubes (1,2) are located at preset angles within a box and contain balls (3,4) which are free to move. The ends of the tubes are closed by insulating caps (5,6,7,8) which have conducting inserts (9,10,11,12) connected to indicating lamps (17,18,19,20). The lamps are supplied from a battery (16) through an on/off switch (22) and indicate any correction required to the slope