Aiming device for indirect fire guns

Claim 1

An aiming device for guns from which projectiles are fired at elevated firing angles in order to provide an arcuate trajectory capable of effecting a hit on a hidden target comprising, a housing fixed to the gun in parallel relation to the firing axis thereof, a first tilt plate vertically mounted in said housing for rotation about a transverse axis therethrough, a pair of gravity sensing units secured to one side of said first tilt plate and oppositely inclined relative to each other to provide an included angle therebetween, an electrical circuit containing means for producing an audible signal during the interval in which the included angle between said pair of units intersects a line parallel to true ground level, adjusting means rotatably mounted in said housing for selective adjustment to a desired reading, cam means rotatably supported in said housing for converting the rotation of said adjusting means to corresponding rotation of said first tilt plate whereby said units are preset to the angle at which the subsequent return thereof to the horizontal during the elevation of the firearm will sound said audible signal to indicate the attainment of the desired firing angle, a second tilt plate pivotally mounted at right angles to said first tilt plate for fore and aft swinging movement designed to maintain a vertical position during the elevation of the firearm, and at least one gravity sensing unit secured to one side of said second tilt plate in electrical connection with said signal circuit for producing an additional signal in the event the gun is canted relative to the horizontal during the elevation thereof to a firing position.