Patent GB-191514060-A (GB)
Title: Improved Means for Directing the Dropping of Bombs or Projectiles from Aeroplanes or Airships.
Inventor: MOLESWORTH HENRY BRIDGES
Filed: 1915-10-04
Abstract: 14,060. Molesworth, H. B. Oct. 4. Sights and methods of sighting.-Relates to sighting-apparatus for use in dropping bombs from aircraft, and comprises an arrangement in which a sight-bar is moved by means of a clockwork-driven screw-and-nut device in order to maintain the line of sight on the target until contact is effected with a member, the position of which is adjusted according to the height of the aircraft, such contact serving automatically to effect the release of the bomb, or to indicate the moment when the bomb should be released. As shown in Figs. 3 and 5, the sight-bar J is pivoted at q to a nut working upon an horizontal screw r and is slidable in a sleeve i pivoted to a block d slidably adjustable in an approximately vertical guide-frame c. The guide-frame c is inclined slightly forward of the perpendicular in order to compensate for lag of the bomb in falling, due to air resistance. Alternatively, the sights may be adjustable, as described in Specification 23,502/14, to allow for the lag. The screw r being driven at a uniform rate by clockwork mechanism within a casing t, the line of sight is maintained on the target by adjustment of the block d in the vertical guides c. The movement proceeds until a contact member o<1> on the nut q meets a corresponding contact o carried by an arm on a nut m adjustable along an horizontallyarranged height-scale l. The contacts serve to complete an electric circuit which either effects the release of the bomb or actuates a bell or other indicator. To prevent damage bv overrunning, the nut q is cut away so that it can be lifted clear of the screw when an arm s attached thereto comes into engagement with a stop p carried by the nut m. By this means also, the nut q may be disengaged to enable it to be moved to any part of the screw to aline the sights on the target. Finer sighting adjustments may be affected by simultaneous movements of the nut q and the adjustable block d. In the arrangement shown, the block d is attached to a rack e which is engaged by a pinion f adapted to be rotated by means of a milled head g actuating a train of intermediate gear-wheels h. The leading-screw r being actuated from the clock-work mechanism through a differential gear v, v<1>, v<2>, v<3>, simultaneous adjustment of the nut q and the block d may be effected by rotating together the juxtaposed milled heads g, w, the milled head g actuating the block d through the gear train h, pinion f, and rack c, whilst the milled head w imparts a rotation to the leading-screw independently of the clock-work mechanism by means of a pinion w<2> driving the planet-carrier of the differential through a gear-wheel w<3> thereon. The apparatus may be adjustable in azimuth and mounted on gimbals, as described in Specifications 23,502/14 and 3009/15, or, as shown, is attached to the " trombone " mounting T of an aircraft. A directing-wire z is provided as a course-indicator. The speed of the clock-work mechanism may be regulated by means of a milled head y actuating a governor. and it may be stopped by means of an arm x. The block d may be actuated by a screw, or may be simply adjusted by hand and clamped in position.