Year: 1889

page_text: I, JOHN SERGEANT BLANKMAN, of 1209, F. Street, N.W. Washington, District of
Columbia, U.S.A., Lawyer, 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 :-
The object of the invention is to provide means for directing the vision with speed
and accuracy toward any object or mark, which means shall be suitable for use with
fire arms and particularly for use with long range guns and rifles. For this purpose
a sight tube which is adapted to guide the eye and to substantially shut out or
exclude every object but the mark, is arranged near the breech and provided with
sight pins, and is made easily adjustable with reference to variations in the direction
of the arm according to differences in the range. This adjustment is effected in
part by raising the sight vertically, as heretofore, and in part by a variation of the
angle between the improved sight tube and the axis of tho weapon, and the various
advantages of the improvement are secured by the devices hereinafter fully described
and particularly pointed out.
In the accompanying drawing,
Fig. 1 represents in side elevation a section of a gun stock and barrel with sight
leaf and adjustable tube.
Fig. 2 is a perspective of the same parts in operative position and partly in
section.
Fig. 3 is a perspective view of the leaf and tube folded down.
Fig. 4 represents a transverse section of the sight tube.
Fig. 5 is a plan view of the adjustable clamp that carries the sight tube.
Fig. 6 represents a blank from which the clamp is produced.
In carrying out my invention I provide a tube 1, from three to six or more inches in
length, and place within said tube two sight pins 2 located in the same plane with each
other and with a diameter of the bore of the tube. This tube, which may be of any
desired form in cross section as also may be its bore, is hinged by means of a screw
or equivalent 3 to an adjustable clamp or sliding bracket 4 of novel form, which slide
is in the present instance represented as applied to a sight leaf 5 of well known

page_text: form. A blank to form this slide can be stamped out of metal in form as shown
in figure 6, which blank may be bent to produce the device represented in other
figures. It is bent into shape to embrace the leaf in such manner that it can be
readily moved up and down or along the same when not clamped upon it by the
action of the screw 3. This screw passes through the perforated wings or arms 6
of the clamp.
It is provided with a head, and may have such connection with the wings or arms
of the clamp as not to turn in its bearings. It is screw threaded at the end opposite
the head to receive a thumb nut, by turning which, the elastic wings of the slide
can be compressed upon the tube, and those portions of the slide which embrace the
leaf are also by the same operation compressed upon and made to firmly hold to
said leaf. This slide, as is obvious, can be arranged to be used with either end
uppermost, and its particular form could also be varied to adapt it to other sight
supports. It can also be entirely omitted and the sight tube journaled or hinged
directly to the barrel or to a base similar to an ordinary sight base, secured in the
barrel. The sight leaf illustrated is very suitable for use with my improved sight
tube, which can be applied without difficulty to such as are already in common use,
the clamp being easily fitted to the leaf and the tube folding down when not in
use between the branches of the leaf and out of the way.
On a side (preferably the upper side) of the tube which is near the breech of the
gun and secured in any suitable manner, is provided a channel 7 which may be of any
form in cross section, and the use of which will be hereinafter described. On the side
of the tube adjacent to the outer extremity of one or both wings of the clamp is placed
a scale, as at S, so arranged that the edge of the wing constitutes an index. The
marks of this scale indicate the proper angles to which the tube must be adjusted to
maintain the direction of its base toward the mark when the direction of the bore of
the gun is varied to obviate the effect of gravity upon the projectile having a large
trajectory. The scale if continued forward of the vertical line, as represented, would
furnish means of adjusting the upward direction of the gun to shoot an object out of
sight, provided its distance and vertical plane were known.
In operation, when the range is comparatively small, for example, about one
hundred yards for a rifle or five hundred yards for a cannon, the sight tube can be:
used in the folded position of the leaf indicated in figure 3, the sight pins 2 projecting
through the wall of the tube as shown. For a greater distance, if the leaf represented
is used, it is opened and the tube adjusted vertically by means of the slide 4, and the
tube turned on its support 3 to adjust its direction to point to the distant mark when
the muzzle of the gun is raised to secure the desired trajectory. The tube being in
proper relative position the thumb nut may be turned to tighten the clamp. The eye
is directed through the tube and to the mark, and when the sight pins within the tube
are brought in line with the eye and the mark the aim is perfected. Sight pins are
used instead of the pin and notch heretofore in common use on gun barrels, for the
reason that the walls of the notch together with the pin would obstruct the vision too
much, though my improvement could be used with a sight notch in the tube.
The tube is located forward of the breech and conveniently near the eye of the
marksman, and the transverse diameter of its bore can be made quite small, for
example, from about one eighth to three-eights of an inch without interfering with
the vision. For long range guns a greater diameter may be desirable. The
rings and sight protectors heretofore placed near the muzzle, .and the short sight
protectors located near the breech have been so large in size and short in length
as not themselves to act as sights since they afforded a view of a large field and
admitted widely divergent rays of light. My tube being about three inches or more
in length and placed near the eye and reduced in diameter would serve as a sight
without the points, though the use of the latter is preferred as they enable the
marksman to take aim more speedily and with a nicer accuracy. The diameter of
the bore of the tube may be varied as desired, but it is usually made for use on
rifles much smaller than the sight protectors heretofore employed.
The groove 7 enables the marksman to take a preliminary aim at or immediately

page_text: prior to the instant when he finally perfects his aim through the bore of the tube. In
some lights or in partial darkness the groove can be used exclusively in taking aim
with good practical effect. It is obvious that the sight pins could be extended through
the tube into view in the groove if desired, and my improvement contemplates such a
construction when wide grooves are employed.
My sight tube enables the usual sight point or sight and protector located at the
muzzle of the gun to be dispensed with, or if one is used permits it to be made of the
simplest form so as not to interfere with the convenient adaptation or application of a
bayonet. The length of the sight tube and its location near the marksman's eye and
its consequently reduced size enable excess of light to be shut out, so that a muzzle
sight point if used needs no protector, and they also enable excess of the field of vision.
to be shut off and an accurate aim secured, even though a muzzle sight point be
wanting. The use of the latter, however, is not inconsistent with my invention.
I have described my device as suitable for use with fire arms, but it is obvious that
it can be used with any gun or instrument which requires means to aid in taking aim
or directing the vision; and as before stated, the particular dimensions named are not
essential as these may be varied according to circumstances; the sight tube, however,
must be more than a mere ring having a length not greater than its diameter.
It is further obvious that the form of the clamp can be easily varied to fit various
leafs or sight supports, and that the particular clamp illustrated can be readily applied
to the inclined spring leaf' now in common use, which leaf or sight support usually has
one end secured to the gun, and is provided with means for elevating the other end,
which latter carries the sight, the leaf being made elastic; and it is further obvious
that the slide may be so fitted to its support as to enable the clamping nut to be
dispensed with without departure from the invention in other particulars; and finally
the details of my device may be varied in unimportant particulars by mechanics
without departure from the invention.
This tube may be made angular or curved in cross section, either as to its body or
its bore, and the angles of the body if it be so made can be chamfered.
Heretofore telescopes have been combined with fire arms to magnify to the vision
of the marksman the object aimed at, and such telescopes have been made adjustable.
about journal bearings to adapt, them to different ranges. Such a telescopic tube
combined with a gun is not of my, invention. I use an open tube for the purpose of
enabling the marksman to speedily narrow his field of vision and direct his sight,
the tube being adapted for distances, such that magnifying glasses are not only not
required, but would tend to defeat my purpose, which, as stated, is to narrow the field
of sight and confine the vision rather than to magnify said field and thus extend the
apparent range of vision. My claim herein therefore is limited to an open tube
having its interior free from lenses or other objects, except that when desired sight
points or equivalents may be used.
"
I am aware that a block having a small aperture or peep sight" resembling a pin
hole has been combined with a sight leaf by means of a hollow screw threaded
extension and milled nut. Such device does not comprise an open tube according
to the present improvement. The hollow extension above described was provided
with a large bore, that could not narrow the field of vision because that was too
much restricted by the " peep sight to permit the extension to have that function.
Such extension is therefore not an open sight tube. Applicant desires to be under-
stood as limiting his claim in this respect to a tube having a bore of substantially
uniform diameter, and to exclude from such claims a block or piece provided with
a "peep hole" and with an extension having an enlarged bore.
"
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
1. In combination with a gun, an open sight tube of substantially uniform bore
secured to the gun to narrow the field of sight and direct the vision, substantially
:

page_text: 2. For use with a gun, a sight tube having a groove in its external wall parallel
with the bore of the tube, substantially as set forth.
3. For use with a gun, an open sight tube, having in its bore two sight pins,
the bore having a practically uniform diameter, substantially as set forth..
4. A sight tube having two sight pins in its bore, and two sight pins on its
exterior, substantially as set forth.
5. An open sight tube journaled to move about a journal or support and in a
vertical plane, in combination with a sight leaf, and with a vertically adjustable
clamp, whereby the tube and its bearings can be moved up or down on the leaf,,
substantially as set forth.
6. An open sight tube having journal bearings in a clamp, the journal having a
screw threaded thumb nut, the elastic clamp, and the leaf all combined, substantially
as set forth, whereby the clamp can be made to firmly hold both the tube and
the leaf.
7. The open sight tube journaled in the folding or hinged support, and said
support adapted to. be attached to a gun in combination with the gun, substantially
as set forth.
8. The clamp to support the sight tube upon the leaf or equivalent part of a gun
adapted to embrace the leaf, and provided with wings having bearings for the journals
of a sight tube, in combination with said tube, substantially as set forth.
9. An elastic sheet metal clamp provided with perforated wings or extensions,
combined with a sight tube and journal, and with a sight leaf or equivalent, sub-
stantially as set forth.
10. An open sight tube adjustable about its bearings provided on its exterior
surface with a graduated scale of angles, in combination with an index, substantially
as set forth.
11. A sight tube, adjustable about its bearings, and provided with a graduated
scale of angles, combined with a clamp which constitutes an index, substantially as set
forth.
Dated thin Oth
1000
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.C.,
Agents for the Applicant.