IMPROVEMENTS IN APPARATUS FOR RIFLING FIRE-ARMS
Year: 1875

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Sutton, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR RIFLING FIRE-ARMS."-A communication from abroad by Captain
Sealed the 1st February 1876, and dated the 25th August 1875.
PROVISIONAL SPECIFICATION left by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition, on the 25th August 1875.
I, GEORGE TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
APPARATUS FOR RIFLING FIRE-ARMS," to be as follows:-
This Invention has for its object to facilitate the forming of parabolic
rifle grooves, which many now regard as the most advantageous. It
applies more particularly to machines in which the bar carrying the
rifling tool is turned by the action of a toothed rack, the extremity of

page_text: which is compelled to travel along a side guide. Up to the present
time this side guide only produces parabolic grooves when a guide of a
curvilinear form is used. In this case the connection between the
toothed rack and the guide instead of being made by two fixed slides
is produced by two rollers only which touch only at a point so as to
follow the variations of curvature which the parabolic form renders
necessary.
The parabolic arc may be replaced by the arc of a circle, the
curvature of which is constant; this allows of the rollers being
replaced by fixed slides of a circular form. But in this case, as 1
in the preceding one, the following inconveniences are met with,-
First. The parabolic or circular guides (of large radius) are difficult
to construct; they can only be imperfectly shaped mechanically, and
the work of finishing by hand is tedious and costly.
Second. It is necessary to have a number of change pieces, as the
form of the guide has to be changed for every change in the inclination
of the rifle grooves, or in their length, or in the diameter of the bore,
or in the diameter of the pinion which engages with the rack. From
this it will be seen that a number of costly pieces require to be made
for arms of different kinds.
The Invention has for its object to remedy these inconveniences, and
to permit of any parabolic curve being made by a single rectilinear
guide merely by varying a series of change wheels similar to those used
in screw-cutting lathes. This arrangement is based upon the principle
that a point can be made to describe any curve by moving it along a
straight line, provided that the line is moveable around a fixed point,
and that its movement is suitably proportioned to that of the moveable
point along itself.
In the particular case of forming the parabolic curves used in fire-
arms the relation maintained between these two movements should be
such that the rate of advance of the moveable
point m on the straight line Ọ, A, measured
P

page_text: bola tangent at O to O, X, and whose diameters are parallel to O, Y,
and to P, A.
The arrangement which seems to me best for forming parabolic
grooves or ribs upon the above principle is as follows:-The rifling
bar is at its end supported by a carriage to which a to-and-fro motion
is given by a long screw parallel with the bar, and the bar has upon it
a pinion gearing with a toothed rack placed at right angles to the bar,
and whose endway movements are controlled, as heretofore, by a guide
at one side of the machine; but in place of this guide being fixed it
turns at one end upon a joint, and at the other end is coupled to a
saddle which works upon a horizontal bed at right angles to the rifling
bar. The bed carries a screw by which the saddle can be moved to and
fro. The screw at one end has upon it a bevil wheel gearing with a
short shaft which is parallel with the axis of the long screw by which
the rifling carriage is traversed to and fro, as before mentioned. The
axis of the long screw and the short shaft are geared with one another
by a system of change wheels, so that the relative speed of the screw
which shifts the guide, and of the screw which gives the endway travel
to the rifling bar, can be regulated as desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Tomlinson Bousfield in the Great Seal
Patent Office on the 25th February 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of August, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said George Tomlinson Bousfield,
Her special license, that I, the said George Tomlinson Bousfield, my
executors, administrators, and assigns, or such others as I, the said
George Tomlinson Bousfield, my executors, administrators, and assigns,

page_text: وو
should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of, Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR RIFLING FIRE-
• ARMS, a communication to me from abroad by Captain Rodolphe, of
the French Artillery, upon the condition (amongst others) that I, the
said George Tomlinson Bousfield, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said George Tomlinson Bousfield, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :-
This Invention has for its object to facilitate the forming of parabolic
rifle grooves which many now regard as the most advantageous. It a
applies more particularly to machines in which the bar carrying the
rifling tool is turned by the action of a toothed rack, the extremity of
which is compelled to travel along a side guide. Up to the present
time this side guide only produces parabolic grooves when a guide of a
curvilinear form is used. In this case the connection between the 2
toothed rack and the guide instead of being made by two fixed slides
is produced by two rollers which touch only at a point so as to
follow the variations of curvature which the parabolic form renders
necessary.
: The parabolic are may be replaced by the arc of a circle, the a
curvature of which is constant; this allows of the rollers being
replaced by fixed slides of a circular form. But in this case, as
in the preceding one, the following inconveniences are met with,—
1. The parabolic or circular guides (of large radius) are difficult to
construct; they can only be imperfectly shaped mechanically, and the 3
work of finishing by hand is tedious and costly.

page_text: 2. It is necessary to have a number of change pieces, as the form of
the guide has to be changed for every change either in the inclination
of the rifle grooves, or in their length, or in the diameter of the bore,
or in the diameter of the pinion which engages with the rack. From
this it will be seen that a number of costly pieces require to be made
for arms of different kinds.
The Invention has for its object to remedy these inconveniences, and
to permit of any parabolic curve being made by a single rectilinear
guide merely by varying a series of change wheels similar to those used
in screw-cutting lathes. This arrangement is based upon the principle
that a point can be made to describe any curve by moving it along a
straight line, provided that the line is moveable around a fixed point,
and that its movement is suitably proportioned to that of the moveable
point along itself.
In the particular case of forming the parabolic curves used in fire-
arms the relation maintained between these two movements should be
such that the rate of advance of the moveable point m (see Diagram,
Figure 1 of the Drawings annexed) on the straight line O, A, measured
by its projection on to O, a, shall be proportional to the advance upon
P, A, of the point A (the junction of the moveable line O, A, and the.
fixed line P, A). The point m by this double movement will describe
a parabola tangent at O to O, x, and whose diameters are parallel
to O, y, and to P, A.
An arrangement of apparatus for forming parabolic rifle grooves or
ribs upon the above principle is shewn in the Drawings hereunto
annexed. In this machine the rifling bar is as usual supported at its
end by a carriage to which a to-and-fro motion is given by a long screw
parallel with the bar, and the bar has upon it a pinion gearing with a
toothed rack placed at right angles to the bar, and whose endway
movements are controlled, as heretofore, by a guide at one side of the
machine; but in place of this guide being fixed it turns at one end
upon a joint, and at the other end is coupled to a saddle which works
upon a horizontal bed at right angles to the rifling bar. The bed
carries a screw by which the saddle can be moved to and fro. The
screw at one end has upon it a bevil wheel gearing with a short shaft
which is parallel with the axis of the long screw by which the rifling

page_text: carriage is traversed to and fro, as before mentioned. The axis of the
long screw and the short shaft are geared with one another by a system
of change wheels, so that the relative speed of the screw which shifts
the guide, and of the screw which gives the endway travel to the rifling
bar, can be regulated as desired.
In the Drawings B is the ordinary framing of the machine; D, the
guide bar for traversing the tooth rack; it turns on a fixed centre at P,
so that its inclination may be varied; g is a flanged rib screwed to the
guide bar, and serving as a rectilinear guide for producing helicoidal
grooves. This rib in former machines has been replaced by a parabolic
guide whenever grooves of a corresponding kind were required. By
my system the rectilinear guide is on the contrary in all cases retained.
A is a frame supporting the moveable end of the guide bar, and adapted
to receive a slide K' which serves to shift the bar to and fro; K is an
intermediate slide for adjusting the initial position of the bar; E is the
screw for traversing the slide K¹; and V, the screw for traversing the
rifling carriage; p, p, are bevil pinions; one (21) keyed to the end
of the screw V, and the other (p) keyed to the axis a; S is a series of
change wheels gearing the axis a with the end of the screw V. The
movement may be reversed for rifling either to the right or left; M is a
moveable pivot for traversing the moveable end of the guide bar; C is
a stud carried by the pivot and entering a short longitudinal slot in the
guide bar; i is an index with vernier for shewing the movements of
the end of the guide bar; and R, a metal scale upon which to read its
movements.
When it is desired to produce a given rifling a very simple calculation
gives the positions that the guide bar ought to occupy at the beginning
and end of the rifle groove, which will allow the workman to determine
the relation of his gear wheels, and to adjust the machine. The fixed
pivot P of the guide bar will ordinarily allow of any rifling which is
likely to be required being produced either to the right or left.
For making rifle grooves with very rapid twist the pivot may be
shifted to the site P¹. In this case a change of direction in the rifling
may be obtained by inverting the position of the end supports.
It is possible that under certain conditions of power of machine
required, or of insufficient space, the transverse dimensions of the above
arrangement might be inconvenient. In this case the guide bar D

page_text: may be replaced by a smaller one mounted upon and carried to and fro
with the tool carriage of the rifling machine B, such smaller guide
bar being similarly carried at one end by a pivot, and traversed to and
fro at its opposite end by an automatic movement; it may be by a
screw driven by a series of change wheels from a pinion gearing into
a fixed rack on the frame of the rifling machine. When this arrange-
ment is employed the slide upon the guide bar may be caused to
traverse to and fro along the bar progressively with the to-and-fro
movement of the tool carriage by passing the link which couples this
slide to the slide carrying the toothed rack through a third slide, which
can be traversed automatically to and fro longitudinally of the tool-
carriage; it may be by means of a screw driven by a series of wheels
from a pinion gearing into a tooth rack upon the frame of the rifling
machine. To allow of the link being thus traversed to and fro longi-
tudinally of the carriage, the end of the link which is connected to the
slide carrying the toothed rack must be so connected to the slide as to
be capable of moving crosswise upon it, the slide being made sufficiently
broad to allow of this movement. By this means as the tool carriage
is traversed to and fro upon the bed of the rifling machine, the
moveable end of the guide bar will be moved to and fro transversely.
of the machine, whilst at the same time the slide which works upon
this guide bar will be shifted to and fro along it, whereby the toothed
rack will be caused to give any desired progressive revolving motion
to the pinion upon the tool bar as the tool carriage traverses to and fro,
and any desired parabolic rifle grooves may thereby be produced. This
arrangement renders the apparatus more compact, and permits of the
necessary calculations being more readily and quickly made. It has
also the advantage that it can be applied to the slides of lathes, and
will, with mechanism of small dimensions, enable them to produce
conical or parabolic turnings, such as the exteriors of cannon and other
such like turnings.
I would state that the Invention is not limited to the precise details
given in the preceding description, or in the Drawings annexed, as
various modifications may be made according to circumstances.
I would also state that the principle is applicable to the rifling of
fire-arms of all calibres, it being only necessary to modify the dimensions
of the parts to adapt them to the work to be done.

page_text: What is claimed is, the arranging machines for rifling fire-arms in
such manner that parabolic rifling, either raised or grooved, may be
produced by the combination of. two rectilinear movements suitably
coupled together, substantially as herein-before described.
16
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Twenty-fourth day of
February, in the year of our Lord One thousand eight hundred
and seventy-six.