IMPROVEMENTS IN MACHINES FOR MANUFACTURING CIRCULAR CUTTERS AND MILLING TOOLS
Year: 1867

page_text: LETTERS PATENT to Paul François Tranchat, of No. 6, Passage des
Jardins, Paris, in the Empire of France, Engineer, for the Invention of
"IMPROVEMENTS IN MACHINES FOR MANUFACTURING CIRCULAR CUTTERS AND
MILLING TOOLS."
Sealed the 3rd January 1868, and dated the 4th July 1867.
PROVISIONAL SPECIFICATION. left by the said Paul François Tranchat
at the Office of the Commissioners of Patents, with his Petition, on the
4th July 1867.
I, PAUL FRANÇOIS TRANCHAT, of No. 6, Passage des Jardins, Paris, in the
Empire of France, Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN MACHINES FOR MANUFACTURING CIRCULAR CUTTERS
AND MILLING TOOLS," to be as follows:-
For the purpose of my Invention I mount the circular cutter to be cut on
a spindle capable of turning on its axis, and provided with a guaged plate or
its equivalent for dividing its circle of rotation in any given number of parts,
and over this stationary cutter to be cut and transversely with its spindle
I place a lever suspended by an universal adjustable joint at one of its
extremities, and containing at a short distance therefrom a small working

page_text: circular cutter adjusted on centres and rotated over the cutter to be cut; at
a distance about five times that of the working cutter from the extremity of
the lever I place an adjustable guide plate on which the lever rests, and
which plate is an enlarged representation of the profile of the cutter to be
cut; by traversing the said lever over this guide plate the working cutter is
traversed over the stationary cutter on which one tooth or cut is thus made
the stationary cutter is then rotated the required amount for another tooth,
and these two successive operations are repeated until the entire circumference
of the stationary cutter has been cut.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Paul François Tranchat in the Great Seal Patent Office on
the 3rd January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PAUL
FRANCOIS TRANCHAT, of No. 6, Passage des Jardins, Paris, in the Empire of
France, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters:
Patent, bearing date the Fourth day of July, in, the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Paul Francois Tranchat, Her special licence that I, the said Paul François
Tranchat, my executors, administrators, and assigns, or such others as I, the
said Paul François Tranchat, my executors, administrators, and assigns, 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. MACHINES
FOR MANUFACTURING CIRCULAR CUTTERS AND MILLING TOOLS," upon the condition
(amongst others), that I, the said Paul François Tranchat, 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 Paul François Tranchat, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following

page_text: statement thereof; reference being had to the accompanying Sheet of Drawings
(that is to say) :-
. For the purpose of my Invention I mount the circular cutter to be cut on
a spindle capable of turning on its axis, and provided with a gauged plate or
its equivalent for dividing its circle of rotation in any given number of parts,
and over this stationary cutter to be cut and transversely with its spindle I
place à lever suspended by an universal adjustable joint at one of its extre-
mities and containing at a short distance therefrom a small working circular
cutter adjusted on centres and rotated over the cutter to be cut; at a distance
about five times that of the working cutter from the extremity of the lever I
place an adjustable guide plate on which the lever rests, and which plate is an
enlarged representation of the profile of the cutter to be cut; by traversing
the said lever over this guide plate the working cutter is traversed over the
stationary cutter on which one tooth or cut is thus made; the station ary
cutter is then rotated the required amount for another tooth, and these two
successive operations are repeated until the entire circumference of the
stationary cutter has been cut.
In order that my Invention be clearly understood I will describe it con-
jointly with the four Figures of the accompanying Drawing, of which Fig. 1
is a plan of my new machine complete, Fig. 2 a front elevation, Fig. 3 a
lateral sectional elevation through A, A, Figs. 1 and 2, and Fig. 4, a Diagram
full size:
.
b
This machine is composed of a table or frame a on which are fitted its four
main or constituent parts, which are, firstly, a small horizontal spindle 6 carry-
ing the cutter to be operated on fitted transversely over the table in a fixed
support &; secondly, a horizontal lever e suspended over the cutter at one of
its extremities by an universal joint, and resting by its other extremity on an
adjustable guide plate f; this lever carries the working cutter; thirdly, a
front adjustable headstock carrying the universal joint; and, fourthly, a back
headstock, also adjustable, to which is attached the guide plate f on which
the extremity of the lever e rests. The spindle b carrying the cutter is fitted
into a little hollow shaft 6¹ which is rotated intermittently in the standard d;
a ratchet wheel 9 is keyed on the extremity of 6', and outside the ratchet I
hang a loose vertical lever h, to which I impart a to-and-fro motion in order
to partially turn the ratchet either in one or the other direction, according to
whether the pawl h¹ is turned over to the right or to the left. The to-and-fro
motion is transmitted to the lever making one revolution of the shaft A
which carries on its extremity a disc h³ with a pin h passing in a slot formed
at the lower extremity of the lever h; this pin ht, as shewn in dotted: linės,
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page_text: Fig. 3, is attached to a small screw h5 by which it can be moved from or
brought towards the centre of the shaft h³ in order to regulate exactly the
throw of the lever, and consequently the number of teeth taken. That the
cutter may remain stationary whilst the cut is being made I make use of a
spring lock which penetrates one of the ratchet teeth, and before rotating
the ratchet the spring is disengaged by the point of the lever i¹ suspended
at To produce this result I fit on the side of said lever a small roller i³; and
I make a nick on the circumference of the disc in which the roller enters
whilst these parts are abreast, but immediately the disc commences to rotate
this roller is expelled from the nick and the spring i disengaged, the roller
remaining in contact with the circumference of the disc until an entire revo-
lution has been completed. The horizontal lever e is suspended at one of its
extremities by the two points e¹, e¹, which enter the disc j, so that without in
any, way moving this disc the lever can be raised and lowered, 'and since the
disc is suspended on the two vertical centres e², e², the said lever can also be
moved in a horizontal direction, and by the combination of these two motions
any point within the range of the lever can be reached. The working cutter k
is fitted underneath the lever e on a spindle k' revolving in bearings k², ; it
is provided with a driving pulley k³ to receive rotary motion, and underneath
the other extremity of this lever I adapt a conical roller turning freely on
the points 1, 1, and which during the cutting rests constantly on the guide
plate f; the taper of this roller should correspond exactly with two lines con-
verging to the centre of the disc j, its axis of rotation being exactly on a line
with the said centre. According to the dimensions of the cutter to be cut it
is necessary that the position of the two headstocks may be varied vertically as
well as transversely; for this purpose with respect to the front headstock I fit
the points e, e², of the disc in a vertical slide m which can be raised or lowered
in the standard m³ by the screw m³, so as to bring the working cutter k on the
top of the circumference of the cutter to be cut whatever its diameter may
be the bolt m³ serves to fix the slide at the requisite height, according to the
depth or thickness of the cutter to be cut. The lever should be moved trans-
versely because it is advantageous that the working cutter should describe
the same angle in order to reach one or the other of its extremities; for this
purpose, I move the standard m² on the saddle m by means of the horizontal
screw m³, and I fix the parts in their requisite position with the bolt me. I
adapt the same arrangement of parts to the back headstock, its vertical motion
being effected by the screw n in the standard n' moving the slide n, whilst the
screw n³ actuates the standard n' transversely on the saddle n; the bolts n
and no serve to hold these parts in their definite positions.

page_text: Working of the Machine.-The cutter to be cut c being fitted on its spindle b
I attach by means of screws or otherwise the guide plate f on the back head-
stock,. which plate represents exactly on an enlarged, scale. the profile: of the
cutter to be cut (in practise. I have found that the. respective relation. of five
to one gives excellent results), taking care that this plate.coincides exactly in
a line with the cutter; I then regulate the position of the lever e so that the
working cutter is brought exactly over the centre of the cutter c whilst the
conical roller is over the guide plate f; I then adjust the position.of the
pin h in the slot of the vertical lever h, according, to the number of cuts to be
made on the cutter. I make sure that the little roller is rests in the nick of
the disc h³, I hold the lever e raised by its handle e, I put the working cutter k
in motion, and lower. laterally the lever e until its roller / bears on the
extremity of the guide f, as shewn at o, Fig. 4, and then pressing on the lever
I pass the roller successively on the entire profile of the plate, thus making
one cut on the cutter; I again raise the lever, bringing it to its former
position, I revolve once the shaft h³ in order to rotate the cutter c the required
quantity, and then make another cut, repeating these motions until the entire
circumference has been cut.
Instead of converging all the cuts to the centre of the cutter it is sometimes
advantageous that they take an angular direction; for this purpose I, have
provided a means of bringing' the working cutter out of the centre of the cutter
being cut by moving the saddle m* with the screw p; and in order to maintain
the same relation of five to one between the cutter and the guide plate I also
actuate the saddle n' by means of the screw 9. This faculty of bringing the
guide plate fcloser to or further from the cutter by means of the screw q is
also of great utility, inasmuch as by varying the fixed relation of five to one it
is possible to augment or to diminish within a perceptible limit the calibre of
the cutters to be cut.
Having thus explained the nature of my Invention, and the best means
that I am acquainted with for putting the same into practise, I claim as my
Invention,―
Firstly, the construction and arrangement of the lever e carrying the working
cutter k and the guide roller l.
Secondly, the universal joint forming the attachment of one extremity of
the lever e.
Thirdly, the construction and arrangement of the two headstocks affording
the means of adjusting vertically, transversely, and longitudinally the position
of the working cutter k with regard to the one being cut c, as well as that of
guide plate with regard to the guide roller l.

page_text: And, fourthly, the arrangement of parts described for imparting inter-
mittent rotation to the ratchet g.
of
In witness whereof, I, the said Paul François Tranchat, have hereunto
set my hand and seal, this Thirty-first day of December, in the year
our Lord One thousand eight hundred and sixty-seven.
Witness,
D. H. BRANDON,
No. 13, Rue Gaillon, Paris.
P. F. TRANCHAT. (L.S.)