Patent GB-930446-A (GB)
Title: Improvements in and relating to a mortar
IPC: F41G1/393
Filed: 1961-06-22
Abstract: 930,446. Mortars. HOTCHKISS-BRANDT. June 22, 1961 [June 28, 1960], No. 22601/61. Class 92. Relates to mortars of the type in which the gun tube A, Figs. 1, 3, in the firing position, is supported by means of a ball swivel joint L on a base plate K and by a wheeled gun carriage. According to the invention an axle 3 is rotatably mounted in a tubular element 6 of the carriage and terminates in two support arms 69 carrying the stub axles of the wheels 2 whereby in rotating the axle 3, the position of the axis of the wheels 2 relative to the gun tube and consequently the elevational position of the gun tube is varied. The carriage comprises a collar B movable along the tube A by means of a device C which provides a fine setting for laying the mortar for elevation and the collar B is supported on a cradle D and can be moved transversely thereof by means of a device E for laying the mortar in azimuth. The collar B is pivoted at 26, Fig. 5, on the cradle D and is also conreacted thereto by an elastically yieldable device F to form a triangulated support system for the tube A. The device F can lengthen or shorten when the tube A tends to modify its angular position relative to the cradle D, e.g. upon firing owing to a rearward movement of the base plate K. The cradle D is mounted on the tubular element G for pivotal movement about an inclined axis W-W contained in the vertical longitudinal plane of symmetry of the carriage and is also connected to the element G by a device H, Fig. 3, whose length is adjustable for rendering the cradle D horizontal irrespective of the transverse inclination of the element G. A device N, Fig. 4, secures the tube A against movement relative to the cradle D when transporting and a device O fixes the base plate K to the tube A when transporting. A sleeve 72, Fig. 12, provided with outer fluting 72a is welded to the axle 3 and is keyed by inner fluting to a worm-wheel 73 meshing with a worm 74 rotatable by a hand wheel 75 to effect the rotation of the axle 3. When transporting the mortar, the teeth of the worm-wheel 73 and the worm 74 are relieved from stress by means of a sliding collar 82 spring-urged to a position to engage the fluting 72a and fluting 49a provided on the tubular element G and moved to and locked in the inoperative position by a hand lever 86. The part-spherical end L, Fig. 16, of the tube engages in a part-spherical socket 93 provided in a detachable plate 94 secured to the plate K. The torque to which the tube A is subjected by the projectile of it is rifled, is absorbed by a shaft 98 engaging in an oblong aperture 99 in the end L and in round apertures 100, Fig. 17, formed in two ears 101 integral with the plate 94. The shaft 98 is pivoted to the ball L by a screw 105 whose axis Z-Z is oblique and situated in the vertical plate P-P of symmetry of the base plate. The oblong shape of the aperture 99 combined with the diamond shape of the shaft 98 (see Fig. 17) permits movement of the gun tube about the axis Z-Z for purposes of laying the gun in azimuth. The sight M, Fig. 3, is mounted by means of a dovetail assembly on the end of an arm 107, Fig. 19, fixed to the collar B. Four studs 109 carried by the arm 107 extend through holes 110 in the collar B and are spring-urged against the gun tube A by a spring 111 which bears against a washer 112 carried by one end of a stud 113 whose other end bears by means of washers 114, 115 against the support arm 107. The stud 113 is slidable in a member 116 welded to the collar B. The female part 120 of the dovetail arrangement is mounted at the end of the arm 107 in such manner as to permit adjustment of the plane of sight so as to render it parallel with the plane of fire and to cause the angle of elevation of the sight to coincide with the actual angle of elevation of the gun tube A. The female part 120 is provided with a stem 121 which is pivotable owing to the provision of a portion of a ball 122 which has a centre Q and is mounted in a part-spherical socket formed on a cup 123 rigid with the arm 107, adjustment being affected by operating a screw 124.