Improvements in the Method of and Apparatus to be used for Sighting and Laying Guns.
Year: 1893

page_text: Date of Application, 3rd Oct., 1893-Accepted, 11th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus to be used for
Sighting and Laying Guns.
We, JOHN CAMERON of Princes Street Port Melbourne in the Colony of
Victoria, and HUGH MACKINTOSH of Number 91 Ross Street Port Melbourne
aforesaid, Engineers, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
Our invention relates to means of facilitating the sighting and laying of a gun
by the use in connection with it of apparatus which we shall describe referring to
the accompanying drawings.
Fig. 1 is a side view of a gun with its carriage and slide with our apparatus
applied thereto, the said apparatus consisting of an upper and lower mirror arranged
on the slide as shewn in perspective by Fig. 2, Fig. 3 being a side view of the
lower mirror, and of an adjustable spirit level and plumb line attached to the
trunnion, as shewn in perspective by Fig. 4.
The upper mirror A is hinged to a sleeve D and to a slotted are F, having
engaged in its slot a pin projecting from an upper sleeve G, and provided with
a thumb nut H. Both the sleeves D and G can slide on a vertical rod E held
in sockets I on the gun slide. The sleeve D can be fixed at the desired
height by a thumb nut on D, and the mirror A can be fixed at the desired
inclination by the thumb nut H. A fine wire C is fixed along the middle of the
mirror A. The frame of the lower mirror B can be fixed by a thumb nut at
the desired inclination on a standard P which can slide in the groove Q of a
base R fixed to the gun slide. In the mirror frame are provided two grooves J J
in which the sides of a moveable frame K can be slid to and fro by
a screw M.
On this sliding frame are fixed three parallel wires L about th of an inch apart;
corresponding with the middle wire a pointer N moves over the side of the
mirror frame which is graduated each way from a zero division in the middle. By
means of the screw M the three wires L can be shifted to right or left so as to
bring the image of the wire C of the upper mirror into coincidence with the
middle wire.
Referring now to Fig. 4, U is an arm fixed to the trunnion V at right angles to
the axis of the gun. To the arm U is attached a graduated segment T, and an
arm carrying a spirit level W and a plumb line X is pivotted on Ū and can be set
to any division of the segment T. and fixed by a thumb nut Y.
As indicated by the dotted lines S in Fig. 1 the gunner sees in the lower mirror B
the image of an object reflected from the upper mirror A, when he has suitably
adjusted the inclination of the mirrors, and trained the gun to the object, and he
can set the wires of the lower mirror relatively to the image of the wire of the
upper mirror so as to allow for wind or for known horizontal deviation of the
projectile. Also he can set the level W on the segment T for elevation and then
elevate the gun until the bubble and plumb are central.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we would have it under-
stood that we make no general claim to the use of the two mirrors in connection
with gun sighting and training apparatus but what we claim is :-
1. The two adjustable mirrors, the upper provided with a central wire and the
lower with three adjustable wires, substantially as described.
2. The arm fixed to the gun trunnion with its graduated segment and adjustable
level and plumb, substantiallly as described.

page_text: 3. In combination with a gun and its slide the pair of adjustable mirrors referred
to in the first claim, and the arm with level and plumb referred to in the second
claim, arranged and operating substantially as herein described.
Dated this 3rd day of October 1893.
ABEL & IMRAY,
Agents for Applicant.