Patent GB-190705716-A (GB)
Title: Improvements in Sighting Apparatus for Ordnance.
Inventor: DAWSON ARTHUR TREVOR
Filed: 1907-03-09
Granted: 1908-03-05
Abstract: 5716. Dawson, A. T., and Horne, J. March 9. Sights and methods of sighting. - Relates to sighting- app'aratu's for ordnance of the type in which corrections for variation in muzzlevelocity and for differences of temperature of the charge and other atmospheric c o nd i t i o n s are made automatically and independently of the range - adjusting devices by means of a known cam-surface. The bracket A, Fig. 1, is attached to the g u n trunnion D, and is formed with a segmental part A<1> and a cam-surface A<2>, Figs. 1 and 4. The part A' forms a guide for the frame C upon which is mounted the telescope C<1>, the frame C being operated by means of a rack c<1> and a pinion c rotated by means of the range dial E. The carrier C<2>, of the telescope is pivoted at c<3> to the free end of a deflexion bar C<3>, which is operated by means of worm gearing c<4> and a deflexion dial C'. The corrections for muzzle-velocity &c. are made by moving the carrier C<2> about the pivot c<2> by means of a pin C<6> and pivoted lever B<1> carrying a roller B to engage with the cam-surface A<2>. A spring c<6> keeps the telescope carrier in engagement with the pin C<6> which, being co-axial with the pivot of the bar C<3>, does not interfere with the setting of the sight for deflexion. The roller B, Fig. 2, is mounted in the frame b<1> so as to be laterally adjustable relatively to the camsurface A<2> by means of a milled head b<4>. The cam-surface may be graduated, in any suitable measure, but preferably the intervals are arranged for foot-seconds increments above or below the mean line 0. With the roller B adjusted laterally so as to be on one side or the other of the mean line 0, the elevation given to the gun will be less than or more than that given by the range-setting device. In a modified arrangement, shown in Fig. 8, the segmental frame A carrying the camsurface A<2> is pivoted to a bracket A x on the gun platform, and is connected by a rod to a bracket carried by the gun trunnion. The frame C is movable about the same pivot by means of the range dial E, and supports a socket Cx through which passes the stem of the deflexion arm C<3>, the lower end of the stem having an arm operated by means of worm gearing and a deflexion dial. The corrections for muzzle-velocity &c. are obtained by means of a spindle C<5> engaging the telescope carrier, and a pivoted lever B<1> carrying the roller B to engage the cam-surface A<2>. The milled head b' of the screw for adjusting the roller B is formed as a drum and has spiral graduations for use with a pointer b<5>. The cam-surface may be traversed instead of the roller. Figs. 11 and 13 illustrate a differential device for enabling the corrections for temperature &c. to be effected mechanically during the setting of the roller B in making muzzle-velocity corrections. The drum for actuating the screw b<3> of the roller B is made in two parts B<4>, B<5> and within one part bevel-wheels b<6>, b<7>, b<9> are arranged. The wheel b<7> rotates with the part B<5> of the drum, the wheels b<9> are loosely carried by a spindle b<10> in the part B<4>, and the wheel b<6> is carried by the screw b3. The roller B is loosely mounted on a nut b<11> prevented from rotating by means of an arm b<12> engaging a groove b<13> in the frame B<x>. The two parts of the drum are grooved, and readers b<17>, b<18> work in conjunction therewith for reading the graduations, and either part may be held against rotation by means of a spring b<16> and small levers b<14>, b<15>. The readers may be loose on a guide-bar and traversed along the bar by engagement with the grooves. In operation, when either part B<4>, B<5> of the drum is rotated to correct for muzzle-velocity or for temperature &c. the wheels b<6>, b<7> move relatively and traverse the roller B.