Improvements in Fore-sights for Firearms.
Year: 1893

page_text: Date of Application, 28th Sept., 1893
Complete Specification Left, 23rd Nov., 1893-Accepted, 23rd Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in Fore-sights for Firearms.
I, LLOYD HEBER CHASE, of "Namoi," Hawthorn Road, Caulfield, in the
Colony of Victoria, Civil Engineer, do hereby declare the nature of this invention
to be as follows:-
With the ordinary sighting on rifles or other firearms and ordnance, the person
taking aim must see the backsight, foresight and target at the same instant. It is
impossible to see all three distinctly at once, and of course the difficulty is still
further increased if the person's sight is defective. Moreover, with the ordinary
sighting, it is necessary to make allowances for the variations in the light.
Now, this improved optical foresight for rifles or other firearms and ordnance
has been devised for the purpose of remedying these defects.
It consists of a lens, or portion of a lens, mounted within a casing so constructed
and arranged that it can be easily and quickly fitted upon or removed from the
barrel of the rifle or other firearm or ordnance, and can be adjusted into such a
position as that its optic centre will be in an imaginary line drawn through the tip
of the foresight, and parallel to the axis of the bore. The focal length of the
lens is equal to the distance of the backsight from its optic centre when fixed, the
effect being that the person taking aim need only look at the backsight in order to
see it and the target image distinctly. This lens should be fitted as near as
possible to the foresight.
With my improved foresight aim can be taken with much less light than is
necessary with ordinary sights as, for example, earlier in the morning and later in
the evening, and a true aim can be made at à lamp or other light at night.
Dated this Seventeenth day of August One thousand eight hundred and
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Fore-sights for Firearms.
I, LLOYD HEBER CHASE, of "Namoi," Hawthorn Road, Caulfield near
Melbourne in the Colony of Victoria, Civil Engineer, 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:-
With the ordinary sighting of rifles and other firearms and ordnance, it is
necessary when taking aim to adjust the sights until the target, fore-sight, and
back-sight are brought into line. In making this adjustment, however, there are
several difficulties to be overcome, the chief ones being the following:
First, It is impossible with the human eye to see these three objects distinctly
at the same instant if either of them is a distance from the others, because when
focussed on one of them it is out of focus with the others.
Secondly, Some persons, though able to see the back-sight distinctly, are
unable to see distant objects distinctly.
Thirdly, The variations in the light cause a difference in the apparent size of
the fore-sight, and thus derange the aim.
Now my improved optical fore-sight for rifles and other firearms and ordnance
has been devised for the purpose of overcoming these difficulties. By it an image
of the target is projected into or near to the plane of the rear of the back-sight.
DQ/1

page_text: As this image and the back-sight are close together and at a convenient distance
from the eye, they can both be seen distinctly, and the person has only to
adjust the weapon until such image and back-sight correspond in order to take a
true aim.
The back-sight being in or near the plane into which the image is projected
serves as a guide to indicate where it is to be seen. If there were no such guide or
beacon for the eye it would be very difficult to distinguish the image.
My improved optical fore-sight for rifles and other firearms and ordnance
consists of either a single or compound lens or part of said lens, and is fixed as
near as possible to the position of the ordinary fore-sight, which I remove;
although if preferred, it may be left in position. The exact position of my
optical fore-sight may be varied, but I prefer to place it with its optical centre as
near as possible to the point at which the line of sight enters the ordinary fore-
sight, the object being to allow the back-sight to be used according to the ranges
marked on it.
The axis of the lens is a straight line joining the optical centre thereof with
that point of the back-sight by which aim is taken when such back-sight is at its
average height, whilst the focal length of the lens is the distance between said lens
and back-sight, the object being to allow the latter to be used according to the
ranges marked on it.
Having now generally described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I will proceed to more
particularly describe the same with the aid of the accompanying drawings,
wherein,
Figure 1 is a side elevation, and
Figure 2 a front elevation of a fore-sight constructed according to this invention,
whilst,
Figure 3 is a vertical central section of said fore-sight, showing it fitted upon
the barrel of a rifle, and
Figure 4 is a side elevation of a rifle fitted with my improved fore-sight.
Figure 5 is a side elevation, and
Figure 6 a front elevation of a fore-sight, such as is now used on cannon or
ordnance.
Figure 7 is a side elevation of the casing containing the lens, which, according
to my invention, I fit within this foresight.
Figure 8 is a vertical central section through such lens and casing.
Figure 9 is a side clevation of a piece of ordnance with one of my improved fore-
sights fitted upon the trunnion.
Figures 10, 11 and 12 are similar views to Figures 5, 6 and 8, but illustrating a
modified arrangement of lens and casing adapted to be fitted over the fore-sight
illustrated in Figures 13 and 14.
In carrying my invention into practice, I mount a lens, A, within a metal
casing, B, and I provide said casing with spring clips, C, to enable it to be fitted
over the barrel, D, of a rifle, as illustrated in Figures 3 and 4. E represents the
ordinary fore-sight of said rifle, and F the back-sight thereof. The lens, A, may
either be single or compound, as hereinbefore mentioned, and its lower part may
be cut away, as illustrated in Figures 2 and 3, to enable it to be fitted in position
upon the barrel, D, it being necessary that its optic centre shall approximately
correspond with the point of the ordinary fore-sight, E; that is, with the line of
sight through such fore-sight. Its focal length is such as to throw the image of
the target or other distant object aimed at into the same plane as the back-
sight, F.
If it be thought advisable to reduce the height of the back-sight, the lens could
be cut, and only so much of it used as to ensure the optical centre being at such a
depth below the ordinary sight that for short ranges the ordinary sight might be
used, and for long ranges, the lens being added, the same height of back-sight could
be used as for short ranges.

page_text: The same effects as those above described could be produced by means of properly
ground mirrors instead of lenses.
With the fore-sight for ordnance or cannon shown in Figures 5, 6 and 9, I prefer
to remove the point from inside the sight, and to screw into the body of such sight
a casing, B, in which is fitted a circular lens, A.
With the fore-sight illustrated in Figures 12, 13 and 14, I prefer to construct the
lens casing, B, with a socket piece, b, adapted to fit over the snug, e, in which the
pointer, E, of the fore-sight is ordinarily secured, said pointer of course being
removed, as illustrated in Figure 12, when the lens is fitted in position.
By forming or providing the fore-sights of rifles and other firearms or ordnance
with a lens as above described, the accuracy with which a person can take aim is
considerably increased, owing to the removal of the difficulties enumerated in the
earlier part of this Specification, and moreover aim can be taken with much
less light than is necessary with ordinary sights, that is, earlier in the morning and
later in the evening, whilst a true aim can be taken at a lamp or other light at
night.
To any person skilled in this class of work it is evident that a special fixing may
be designed suitable to each pattern of weapon, and I have therefore illustrated
fixings for the most widely differing classes. It is also evident that the position
of the optical fore-sight may be altered so long as its focal length is equal to
its distance from the back-sight, but that the ranges marked on the back-sight
must be specially adjusted for each position. In some cases special lenses may
be necessary, as for instance with ordnance for coast defence which is sometimes
aimed in azimuth only, in which case a cylindrical lens could be used.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:
First. A fore-sight for rifles and other firearms and ordnance consisting of a
single or compound lens or a portion of a lens, the focal length of which is the
distance between it and the back-sight, substantially as herein described and
explained and as illustrated in the accompanying drawings.
Second. A fore-sight such as is described in the first claim in this Specification
in which the lens has its lower part cut away substantially as and for the purposes
herein described and explained and as illustrated in the accompanying drawings.
Third. A fore-sight such as is described in the first claim in this Specification
in which the lens or portion of a lens (as the case may be) is provided with a
casing having clips (such as C) substantially as and for the purposes herein
described and explained and as illustrated in Figures 1 to 4 of the accompanying
drawings.
Fourth. A fore-sight such as is described in the first claim in this Specification,
in which the lens or portion of a lens (as the case may be) is provided with a
casing (such as B) adapted to be screwed or otherwise fitted into the ordinary
tubular fore-sight of ordnance substantially as herein described and explained and
as illustrated in Figures 5 to 9 of the accompanying drawings.
Fifth. A fore-sight such as is described in the first claim in this Specification
in which the lens provided with a casing (such as B) having a socket piece (such
as b) adapted to be fitted over the base of an ordinary fore-sight for ordnance
substantially as herein described and explained and as illustrated in Figures 10 to 14
of the accompanying drawings.
Dated this Seventh day of October One thousand eight hundred and ninety-