Patent GB-191423790-A (GB)
Title: Improvements in or relating to Guns on Aeroplanes.
Inventor: EDWARDS ARTHUR HENRY
IPC: F41A19/05
Filed: 1914-12-09
Abstract: 23,790. Edwards, A. H. Dec. 9. Firing appliances; machine rests; safety appliances.-Consists in means for preventing guns, such as rifles, mounted on aircraft from being fired when a propeller blade or a fixed part of the aircraft is in the line of fire. In the form shown in Figs. 1 and 2, a spherical segment C is keyed to a short shaft C<1> arranged parallel to the propeller shaft E<1> and geared thereto by means of a vertical shaft D<1> and two pairs of bevel wheels C<2> D<2>, D<3>, E<3>. The spherical segment C is cut out in parts to correspond on a smaller scale to the propeller E as shown in Fig. 4, and the end F' of a lever F is arranged to bear against the segment C and to be deflected periodically thereby and to transmit this periodical oscillation to a slide rod G, which serves to lock and to unlock the firing mechanism of a rifle A. The rod G is pressed forward to press the lever F against the segment C by means of a spring G<1> which abuts against a collar H' on another slide rod H pressed by a spring H<3> against the trigger I. The trigger I carries a spring I<3>, which, when the trigger is pulled, bears against a pin J<3> on a bell-crank lever J J<x> and tends to turn this lever and thereby to pull the sear K from the catch L<1> of the firing hammer L. The bell-crank lever J J<x> carries a small pawl J<2> disposed over the end G<4> of the slide rod G and over a lug H<4> projecting from the rod H. When the trigger is pulled, the rod H is pushed forwards and the lug H<4> moves away from under the pawl J<4>, but this pawl is fully released only when the segment C allows the rod G to move forward; only then can the lever J J<x> be turned by the spring I<3>, and the gun be fired; the segment C being correctly timed relatively to the propeller thus prevents the firing when a propeller blade is in the line of fire. The rifle is mounted on the part B of the aircraft by a support comprising a base piece B<4> with a vertical standard B', a fork A<3> A<4> rotatably mounted on the standard, and another fork A<2> A<1> pivotted by horizontal pivots a to the first fork and carrying the rifle A. The shaft D' is arranged within the standard B<1>. The rifle may be made detachable from its support. The cut out segment C may be replaced by a segment having raised ribs or parts, and may be arranged to draw the rod G forwards instead of pressing it rearwards. The lever F may be arranged to bear against the concave instead of against the convex side of the segment C. In a second form shown in Figs. 6 and 7, the rifle A is mounted on a support comprising a tube R rotatably mounted at the lower end R' on the bearing of the propeller shaft E' and connected at the upper forked end R<7> by horizontal pivots R" to a horizontal ring R'‹ within which is rotatably mounted another ring R<9> pivoted to a fork R<8> directly carrying the rifle A. The segment C is geared to the propeller shaft E' by the spindles R<6> R<3>, and the bevel wheels R<5> R<4>, R<2> E<2>, as in the first form; but the spindle R<6> is directed towards the centre of the propeller and the lever R<16> which bears against the segment C is connected to the slide rod G through another lever R<18> instead of directly as in the first form. Finally, the ring R<10> is further connected to the base B by a pivoted link R<12>, thus forming a parallel motion which enables the rifle to be swung about laterally and trained and elevated while maintaining the spindle R<6> of the segment directed towards the centre of the propeller, and thus ensuring the proper control preventing firing when a propeller blade is in the line of fire. In a third form shown in Figs. 8 and 9, the rifle A is carried by a support comprising link-work motion S'‹, universal joints S<4> S<7>, S<12> S<15>, and telescopic shafting S<5> S<6> enclosed in a telescopic covering S<11>, S<13>, enabling the rifle to be moved about in all directions within certain limits while maintaining the spindle S<8> of the segment C directed towards the centre of the propeller and thus preventing firing when a propeller blade is in the line of fire. A spring cup connexion S" is deflected when the rifle is moved beyond the limits allowed by the mounting. In a fourth form shown in Fig. 11, the rod G is connected by two bell-cranks X X<1> to a bar X<2> which bears against a spring-controlled lever F<x> connected to the lever F. The lever F bears on a segment C rotated by the propeller shaft as in the other forms, and the lever F<x> bears against a fixed segment C<x> provided with raised parts C<xx> corresponding to obstructions on the aircraft in the field of fire. The trigger mechanism comprises three rotary parts a, e, f on the same spindle b; the first part carries the trigger I, the second e acts on the sear K, and the third transmits the action of the first part or trigger to the second part e, suitable springs and co-acting pawls and catches being provided as shown. The rifle has a tongue T by means of which it is detachably connected to the socket T<1> of the mounting. In a fifth form shown in Fig. 12, the fire control is electrical. The mounting comprises a vertical spindle U' and a link U<3> forming a parallel motion therewith. A lever U forming part of the parallel motion bears against the concave face of the segment C which is keyed directly to the propeller shaft E<1>. The lever U carries a spring tip U<4> controlling a contact maker in the circuit of an electro-magnet U<6>, the armature U<10> of which when attracted releases the sear U<11>. This form also includes a fixed segment C<4> co-acting with a lever U<3> forming part of the parallel motion and provided with a contact controlling tip U<7> for cutting the circuit of the electromagnet U‹ when a fixed part of the aircraft is in the line of fire. Specification 16726/13 is referred to.