Improvements relating to Sighting and Indicating Apparatus for Ordnance.
Year: 1892

page_text: Date of Application, 16th Jan., 1892
Complete Specification Left, 15th Oct., 1892-Accepted, 14th Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements relating to Sighting and Indicating Apparatus for
Ordnance.
I, HUBERT HENRY GRENFELL, of 18 Ashburn Place, in the County of
Middlesex, Captain Royal Navy, do hereby declare the nature of this invention to
be as follows:-
In the Specification of former Letters Patent dated 17th November 1888, and
numbered 16760, I have described a sighting apparatus wherein there is an
improved range indicator in combination with a curved sight-bar. The said range
indicator has two rotary discs upon which the figures denoting hundreds and
thousands are marked. The said discs are enclosed in a case formed or fixed on
the sight bar socket. The case has an outer disc or cover wherein I form a slit or
aperture through which the figures on the rotating discs can be seen. In line with
this slit or aperture I mark on the cover two or more cyphers followed by the word
"yards." These cyphers with the figures which appear through the said slit or
aperture indicate the number of yards of the range or distance of the object at
which the gun is pointed. One of the rotating discs is fixed upon a spindle which
extends through a hollow spindle that carries the other rotating disc. The inner
spindle has on it a pinion which gears with the rack of the sight-bar. At regular
intervals in the series of rack teeth there are extended or long teeth which form
another rack to gear with a pinion on the hollow spindle for intermittently rotating
the disc carried thereby.
My present invention consists chiefly in the combination of a range indicator,
such as that above described, with a straight sight bar by means of a peculiar
arrangement of gearing whereby notwithstanding the varying lengths of movement
of the bar to correspond with the equal increments of range of the gun the
indicator discs are operated in such a manner as to give equally clear and distinct
indications of all ranges of the gun.
For this purpose
attach the case or box of the indicator to the sight-bar socket
in any convenient position. I also form or fix on the said socket a bracket for
carrying a spindle the outer end of which is provided with a milled wheel or disc
and the inner end of which carries an ordinary toothed pinion which gears with the
rack on the sight-bar.
The said spindle also has fixed on it a spirally formed taper wheel or spiral
rack having a series of teeth on its peripheral surface. These teeth gear with a
pinion on the spindle of the indicator which spindle has its inner end supported
in a bearing on the aforesaid socket. The spiral wheel consists of a number of
turns around its axis and varies in diameter throughout the entire length of its
periphery. It is therefore obvious that special provision must be made for keeping
it in gear with the pinion on the indicator spindle.
With this object I arrange the said pinion within a box which is fitted to slide
upon a square part of the indicator spindle and has cheeks which extend over the
edge of the spiral wheel and which is arranged in combination with a guide on the
socket so that as the spiral wheel presents different parts of its periphery to
the pinion the latter slides upon the indicator spindle and thereby maintains its
proper connection with the said spiral wheel.
It will be seen that as the straight sight-bar is moved through varying lengths
by the continuous rotation of the spindle of the spiral wheel in either direction the
indicator spindle moves through uniform parts of a revolution. And if the proper
relative proportions of the parts have been secured in the construction and arrange-
ment of the same the varied movements of the bar which correspond with the

page_text: different angles of elevation of the gun for similar increments of the range will be
correctly recorded and shewn on the indicator as above described. I thus obtain
with a straight sight-bar the advantage which I have heretofore obtained with a
curved bar in respect of clear and distinct indications of all ranges or distances for
which the gun is used.
Dated this 16th day of January 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements relating to Sighting and Indicating Apparatus for
Ordnance.
I, HUBERT HENRY GRENFELL, of 18 Ashburn Place, in the County of
London, Captain, Royal Navy, 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 :-
In a sighting apparatus previously invented by me and described in the
Specification of former Letters Patent dated 17th November, 1888, and.
numbered 16760, there is an improved range indicator in combination with a curved
sight bar. The said range indicator has two, three, or more rotary discs upon
which the figures denoting tens, hundreds, thousands, and tens of thousands. if
required, are marked. The said discs are enclosed in a case formed or fixed on the
sight-bar socket.
The case has an outer disc or cover wherein I form a slit or aperture, through
which the figures on the rotary discs can be seen. In line with this slit or aperture
I mark on the cover one two or more cyphers, followed by the word "yards" or
by such other word as will indicate the nature of the unit of measurement for which
the apparatus is adapted; these cyphers, with the figures which appear through
the said slit or aperture, indicate the number of yards, for example, of the range
or distance for which the sights are adjusted.
One of the rotary discs is fixed upon a spindle, which extends through a hollow
spindle that carries the other rotary disc. The inner spindle has on it a pinion
which gears with the rack of the sight-bar. At regular intervals in the series of
rack teeth there are extended or long teeth, which form another rack to gear
with a pinion on the hollow spindle, for intermittently rotating the disc carried
thereby.
My present invention consists chiefly in the combination of a range indicator,
such as that above described, with a straight sight-bar by means of a peculiar
arrangement of gearing, whereby, notwithstanding the varying lengths of move-
ment of the bar to correspond with equal increments of range of the gun, the
indicator discs are operated in such a manner as to give correct indications of
equal clearness, for all ranges of the gun.
In order that my said invention may be clearly understood I will now proceed to
describe the same with reference to the accompanying drawings in which :-
Figure 1 is a sectional elevation of one form of an improved sighting and indicating
device constructed according to my invention, and
Figure 2 is an elevation of the same at right angles to Figure 1.
Like letters of reference indicate corresponding parts throughout the drawings.
A is the case or box of the indicator, B is the sight-bar socket on the gun, B' is
a bracket formed upon the socket B. C is a straight sight-bar with a toothed rack
formed thereon, D is a spindle carried in said socket, E is a milled wheel or disc
secured to the outer end of the spindle D. F is an ordinary toothed pinion secured
to the inner end of the spindle D and gearing with the rack on the sight-bar. The
said spindle also has fixed on it a spirally formed taper wheel or spiral rack G

page_text: having a series of teeth on its peripheral surface as shown. H is the indicator:
constructed as herein before described. I and J are the rotary indicating discs
thereof, geared together by any suitable means, and K is the outer disc or cover.of
the indicator, through the slits or apertures K' of which the figures on the rotary
discs can be seen, as in Figure 2. It is obvious that the tens may be indicated by
a rotating disc, and also that a disc may be provided to indicate tens of thousands
if desired.
L is a pinion on the spindle M of the indicator which spindle has its inner end
supported in a bearing on the aforesaid socket B. The said pinion L gears with
the wheel G, which consists of a spiral having a number of turns about its axis, ;
and of varying diameter through the whole length of its periphery; it is therefore
obvious that special provision must be made for keeping the said pinion L in gear.
with the wheel G.
With this object I arrange the said pinion within a box L' which is fitted to
slide upon a square part M of the spindle M and has checks L' which extend
over the edge of the spiral wheel, and which is arranged to engage with a guide B³
on the socket, so that as the spiral wheel presents different parts of its periphery
to the pinion the latter slides upon the part M' of the spindle and thereby maintains
its proper connection with the said spiral wheel.
:
The operation of the said improved sighting and indicating device will now be
described It will be seen that while the velocity ratio of the straight sight bar C
with respect to the spindle D is constant that of the indicator-spindle M, with
respect to the spindle D is variable, and if the proper relative proportions of the
parts have been secured in the construction and arrangement of the same, the
varied movements of the bar C which correspond with the different angles of elevation
of the gun for similar increments of the range, will coincide with a constant movement
of the indicator disc J, and the range therefore in every position of the gun will
be correctly recorded and shown on the indicator. I thus obtain with a straight
sight-bar the advantage which I have heretofore obtained with a curved bar in
respect of clear and distinct indications of all ranges or distances for which the
gun is used. This is obviously a most important advantage, readily obtainable
according to my invention, which invention I do not limit to the aforesaid
exemplification of the manner in which it may be put into practice, seeing that
there are many other similar arrangements of mechanism whereby a like result
can be secured. For instance, instead of the conical spiral wheel GI may employ
a disc with an involute rack formed upon the face thereof to gear with a wheel by
which the indicating discs are operated, the variation of the radius of the involute
being proportionate to the required variation of linear movement of the straight
sight-bar. Or I may place a fusee wheel upon the spindle D and cause it to operate a
spring-barrel by means of a chain, as in clocks and watches; in this arrangement
the fusee takes the place of the coned spiral or of the involute rack, and the
barrel is preferably provided with numerals upon its periphery, which are visible
through a suitable aperture to the indicator casing and are employed to indicate
"hundreds." A drum, cylinder, cylindrical segment, or the like, is similarly
employed to indicate "thousands" and is operated from the said barrel by means
of a pin on the latter which gears with a star-wheel on the former or on a suitable
spindle geared to the former. A spring is suitably arranged to bear upon the
star-wheel or the mechanism operated thereby, in order that movement of the
"thousands" drum, cylinder, or segment, may only take place when effected by
the aforesaid stud.
I sometimes attach a small electric glow lamp to the apparatus for illuminating
the dial to facilitate night reading.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A combined sighting and range indinating device hazing

page_text: and a positive gear connection between the said bar and the indicator, which gear
is adapted to produce a variable velocity ratio, for the purpose specified.
2. The combination, with a straight sight-bar, of a range indicator, and gear
which includes a conical toothed wheel connecting the sight bar with the indicator,
substantially as described for the purpose specified.
3. The mode of mounting and driving the pinion L substantially as described
for the purpose specified.
4. The combined sighting and indicating device, constructed substantially as
described with reference to the drawing, with or without a glow lamp and operating
as specified.
'
5. The modified device wherein the conical spiral wheel is replaced by a flat
spiral or by a fusee, substantially as herein described.
Dated this 11th day of October 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.