Improvements in Lathes; chiefly designed for the Manufacture of Screws.
Year: 1891

page_text: Date of Application, 21st Feb., 1891-Accepted, 4th Apr., 1891
COMPLETE SPECIFICATION.
Improvements in Lathes; chiefly designed for the Manufacture
of Screws.
We, HUBERT HENRY GRENFELL, of 18, Ashburn Place, in the County of
Middlesex, Captain R.N., and PETER BARON, of Eagle Wharf Road, Hoxton, in
the County of Middlesex, 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 :-
Our invention relates to machinery or apparatus chiefly designed for the manu-
facture of screws.
An important feature of our said invention consists in mounting the tool-holders
in a suitable carrier which is adjustable about an axis parallel to the bed of the
machine. For this purpose we provide in the said carrier, spindles or mandrels
arranged horizontally or parallel to the axis of the said carrier, and provided with
sockets to receive the tools. These spindles, mandrels or tool-holders are arranged
in a circular series, that is to say, at equal distances from the axis of the said
carrier so that, by turning the latter about its axis, the tools can be consecutively
brought into their operative position.
Another feature of our said invention is the provision of means for locking the
said carrier so that either of the tool holders may be firmly secured in its operative
position.
Our said invention comprises, moreover, improved means for chucking or centring
the rod, wire or blank, and for holding and rotating the same whilst the screws or
other articles are being formed therefrom.
Our said invention also comprises improved means whereby we provide for
regulating the length of the portion of the rod or wire subjected to the action of
the tools. And our said invention further comprises other improvements hereinafter
set forth.
In the accompanying drawings we have shown how our said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a plan partly in horizontal section.
Figure 2 is a front elevation partly in vertical section.
Figure 3 is an end elevation and
.
Figure 4 is a transverse section on the line, a Figures 1 and 2 showing one
form of our improved machine or apparatus for manufacturing screws, and other
articles.
Figures 5, 6, 7 and 8 are plans partly in horizontal section, drawn to an enlarged
scale illustrating the different stages in the manufacture of a screw by our improved
machine.
Figure 9 is a rear elevation partly in vertical section, and
Figure 10 is a vertical central section partly in clevation drawn to the same scale
as Figures 5, 6, 7 and 8.
Figure 11 is a horizontal section on the line y. y, Figure 2 drawn to a still further
enlarged scale, and
Figure 12 is an end elevation partly in vertical section drawn to the same
scale as Figure 11 and some of the parts being removed showing details of
construction.
Like letters indicate corresponding parts throughout the drawings.
A is the bed of the machine which is substantially similar to that of an ordinary
lathe. B is a head firmly secured to the bed A. at one extremity thereof. C is a
hollow mandrel fitted to rotate in suitable bearings B₁ in the head B. D is a speed

page_text: cone formed or fixed upon the mandrel C. E is the driving belt or band. F is the
wire, rod or blank from which it is intended to manufacture the screws.
a is a movable head or saddle fitted to slide freely to and fro upon V shaped or
other suitable ways provided on' the bed A is a rack firmly secured to or formed
on the bed A. e is a pinion which is mounted-upon a spindle c' supported in suitable
bearings in an.extension or bracket a firmly secured to or formed on the saddle a
and is geared with the rack b. is a hand-wheel which is secured upon the outer
extremity of the spindle c', and whereby the latter can be rotated so as to impart a
to and fro movement to the saddle along the bed A. eel, e² are mandrels or tool-
holders supported in suitable bearings in discs or conical pieces f mounted in corre-
spondingly shaped holes a² in extensions a³ of a block or head a* which is supported
upon suitable ways on the movable head or saddle a and is secured thereto by bolts
and nuts, set screws or in any other convenient manner, so as to be capable of
longitudinal adjustment relatively thereto. The discs or conical pieces are fitted
to turn freely in the said extensions a³ and are secured or coupled together by means
of a bolt stay or distance piece f¹ thus forming what I term the carrier. The
mandrels or tool-holders e, are hollow or tubular and are provided at their forward
ends with hollow collars or sockets e³ in which are firmly secured by means of set
screws or in any other convenient manner so as to be readily removable there-
from, cutter heads g, g' for the purpose hereinafter described. e, are collars
adjustably secured by means of set screws or in any other convenient manner upon
the other or outer ends of the said mandrels e, e¹.
Es
AL
are V-shaped or other suitable feathers secured to or formed on one of the
discs or conical pieces f and fitting into suitable key ways or grooves e* in the
mandrels el so as to admit of their moving freely to and fro in the said discs or
conical pieces but to prevent any rotary movement thereof. The mandrel or
tool-holder is so arranged that it is free to move to and fro in the discs or conical
pieces and also to rotate therein and is provided at its forward end with a collar
or enlargement et having a suitable recess in which is secured by means of a set
screw e or otherwise so as to be readily removable therefrom a die for cutting
screw thread of the required pitch. e' is a milled head or knob mounted upon the
rear end of the said mandrel e so as to be capable of rotating freely thereon. The
mandrels or tool-holders e, e', e² and discs or conical pieces are so arranged that
when the latter are turned or rotated so as to bring one or other of the said mandrels
into the highest position the axis of the said mandrel will be coincident with the
axis of the hollow mandrel C. The rod or wire F to be operated upon is passed
through the hollow mandrel C and through a bush fitting easily upon the said rod
or wire and arranged in a hole as formed in an extension a of the saddle a.
said bush i is held in position by means of a set screw and when the set screw is
slackened, can be easily removed and replaced by another one to correspond with
the dimensions of the rod or wire to be operated upon. is a chuck secured to or
formed on one extremity of the hollow mandrel C. The chuck j is fitted with
jaws, which are adjustable in suitable grooves or ways to or from the rod or
wire by means of set screws kk. The set screw k is provided with a square
head adapted to receive a wrench, and is adapted to move the jaw j; the set
screw is provided with a nick or slit for a screw driver and is adapted to move
the jaw j.
The
In centring or chucking the rod or wire one of the said jaws preferably the
jaw j is first adjusted so as to set the rod wire or blank F perfectly true and the
jaw is then screwed up so as to grip, clamp or secure the said rod or wire F
firmly in position between the said jaws. Then by slackening the set screw kat
any time, the wire or rod F can be released and moved forward through the chuck j.
We are thus enabled to ensure the operator always slackening the same jaw when
moving forward the rod, wire or blank and thus prevent the latter from getting out
of truth when the said operation is frequently repeated.
is a catch or detent coupled at by means of an anti-friction roller working in
a suitable recess or slot, or otherwise to one arm of a bent or bell crank lever ľ

page_text: pivoted at to lugs a formed on or secured to one of the extensions a³. The
catch works in a hole as formed in the said extension a³ and engages (as more
clearly shown in Figure 10) in one or other of a series of holes f³ formed in the
corresponding discs or conical piece f, in such a position relatively to cach of the
mandrels or tool-holders e, e', e that when the said catch is engaged in either of
the said holes, the conical pieces, will be locked firmly in position and the axis of
the uppermost of the said mandrels will coincide with the axis of the hollow
imandrel C m is a spiral spring which is arranged in a hole or recess m in the
extension a³ (as shown in Figure 12) and which acts through a rod or plunger m²
upon the lever 12 so as to retain the catch engaged in one or other of the
holes³
We provide moreover suitable means for locking or retaining the mandrels or
tool-holders e, e in their forward or operative positions, and for regulating or
determining the length of the finished screw to be formed on the rod or wire F,
that is to say-We form in each of the said mandrels a key-way or groove
(Figure 10) and we fit therein a suitable strip or key n having a notch ¹ formed
in its upper surface. Set screws are provided in the collars for securing the
strips or keys n in position, whilst permitting the longitudinal adjustment thereof
in the grooves when desired. When the mandrel e or el is moved forward or into
its operative position, the stop drops into the notch n' and locks or secures the said
mandrel in position. The forward or operative positions of the mandrels e
el can
be regulated by adjusting the keys or strips n as above mentioned in the key ways
or grooves eo, o are spiral springs surrounding the mandrels e, e. One extremity
of each of the said springs o bears against one of the conical pieces, and the other
extremity thereof bears against a collar e firmly secured to the mandrel by means
of a set screw el or in any other convenient manner.
Pare
PP are rods arranged within the mandrels or tool-holders e el and having reduced
portions p adapted to fit into the holes in the cutter heads gg'. The said rods
adjustably secured in the said mandrels or tool-holders e e by means of set
screws el or otherwise. By adjusting the said rods p, the length of cut to be made
upon the rod or wire F by the said cutter heads can be regulated.
We provide suitable means for preventing rotation of the mandrele carrying the
screw cutting die h during the time requisite to admit of a screw-thread of the
desired length being cut upon the rod or wire F and to permit the length of the said
screw-thread to be varied at will. For this purpose, we employ, the device shown
more clearly in Figures 6, 7, 8, 9 and 12, that is to say is a rod or bar firmly
secured to the rearmost disc or conical piece and of a square or other suitable
form in transverse section. is a sleeve or collar fitted to move freely to and fro
upon the rod or bar but prevented from rotation thereon by reason of the section
thereof, or by any other convenient means. ss are collars secured upon the said
rod or bar by means of set screws or otherwise so that they can be adjusted at
will. is a rod or plunger (more clearly shown in Figure 9) fitted in a suitable
hole or recess formed in an enlargement of the collar s, and acted upon by a
spiral springs. The sleeve or collar is arranged upon the rod or bar between
the collars ss and is retained against the collars by the spring rods.
Ribs or
feathers are formed on the sleeve or collar 7, cach of which is bevelled or cut
away at one extremity as indicated at 3. A collar is moreover secured upon the
manilrel e in such a manner that it is adjustable thereon by means of a pin t'
adapted to fit into a hole formed in the said collar, and to engage in one or other.
of a series of holes 3 provided in the said mandrel 2. A projection formed on
or firmly secured to the collar tis adapted to engage with one or other of the ribs
or feathers, and the mandrel e during its forward movement is thereby prevented
from rotating in the carrier. When however the said projection t³ (in the forward
movement of the mandrel e whilst cutting or forming the screw-threads upon. the
rod or wire F) attains the position shown in Figure 7 it acts upon the inclined,
bevelled or cut away portion of the rib or feather so as to press or force back

page_text: the sleeve or collar against the spring and permit the rotation of the mandrel
or tool-holder e², the spring yielding or being compressed and reacting at each
impact of the projection with the rib or feather The cutting action of the
screw cutting die is thus arrested. The end of the said feather or projection is
in some instances also slightly cut away or bevelled in order to facilitate its passage
over the cut away or bevelled part 2. When the movement of the hollow mandrel C
and consequently that of the rod wire or blank F is reversed the said projection ³
strikes against the underside of the rib or feather, the end of which is not cut
away or bevelled and the rotation of the mandrel or tool-holder is consequently
again arrested so that the said screw cutting die is moved backwards or unscrewed
from the rod or wire F. The mandrel or tool-holder e² can be manipulated by
means of the loose knob or handle e to cause the engagement of the screw cutting
die with the rod wire or blank F or to assist its disengagement therefrom. By
adjusting the collars and collar or sleeve upon the rod or bar y, or the collar t
upon the mandrel e or both, the length of the screw-thread cut upon the wire or
rod F can be regulated. Should one of the ribs or feathers become worn or
damaged, the collar or sleeve » can be removed from the rod or bar and turned so
7
are
as to bring another of the said ribs or feathers into the operative position.
u is a slide rest arranged to be moved transversely to the bed A in suitable ways
on the saddle a by means of a screw threaded spindle a provided with a handle u².
The slide rest is provided at each end with a tool holder ³ of any suitable
description, in one of which is secured a tool for completing the formation of the
head of the screw and cutting or severing the latter from the rod F.,
adjustable stops for regulating the movement of the said slide rest « in both
directions. The stops are arranged in heads or bosses on bolts or spindles »²
passed through suitable holes provided in extensions on the slide rest, and
secured therein by nuts as shown more clearly in Figure 11.
In combination
with each of the bolts or spindles moreover is provided a stop v arranged as
shown in Figure 11 in a hole or recess in the slide rest u, and one extremity of
which is rounded, and engages in one or other of holes or countersinks in the
said bolt or spindle under the action of a spiral spring . The holes or counter-
sinks are so arranged that when the rounded end of the stop or pin
engages in
one or other of the said holes or countersinks one of the stops will be in its
operative position and will engage with the movable head or saddle a and arrest the
forward movement of the slide rest. w and tool ut. The bolt or spindle »²
is retained in position by the stop or pin but can be turned or adjusted so as to
bring one or other of the said stops into its operative position, the rounded end of
the said stop or bolt being forced out of the hole or countersink in which it was
engaged compressing the spring and dropping into, or engaging in the next or
succeeding hole or countersink under the reaction of the said spring.
w is a bent arm or lever (Figures 1, 2 and 3) pivoted at w' to a lug a formed on
or firmly secured to the extension a. One arm or the short arm of the lever wis
provided with a socket 2 in which is adjustably secured by set screws wor
otherwise a rod bar or holder upon the lower or one extremity of which is
intended to be mounted a suitable milling tool or cutter. The other or long arm
of the said lever w forms a handle by means of which the said milling tool or cutter
can be moved into position to operate upon the head of the screw.
A suitable countershaft (not shown in the drawing) connected with the main
shafting by a crossed and straight belt and suitable striking gear or other means for
reversing the motion thereof are moreover provided.
When the rod or wire is untrue and of varying diameter, or when the diameter
thereof is larger than is required to form the head of the screws we sometimes
remove the cutter head and adjusting rod from the mandrel or tool-holder e or e¹ and
secure a suitable cutter head in the hole as in the extension af on the saddle a in
place of the bush i. This cutter head may be either left permanently in position, or
the movable head or saddle a may be traversed through the entire length of the

page_text: bed A, and the entire length of the rod or wire turned down or reduced, after which
a bush corresponding to the reduced diameter of the said rod is secured in the said
hole a and the rod or wire is replaced in position as before.
is.
The operation of the apparatus is as follows, that is to say; The mandrel or tool-
holder e carrying the cuttery for making the roughing or first cut is brought into
line with the wire or rod F by turning the carrier about its axis, and the latter is
then locked in position by the catch, detent or bolt 1. The said mandrel or tool-
holder e is moved forward and also locked or secured in position by means of the
said catch or detent. I, and the movable head or saddle a is moved forward by means
of the hand wheel d, spindle e pinion c, and rack so that the cutter head
forced upon the rod wire or blank which is firmly held in the chuck and rapidly
rotated with the said chuck and the hollow mandrel C, until the end of the rod P
comes in contact with the said rod or blank. The end of the said wire or rod F is.
thus turned down or shaped (as shown in Figure 5) so as to permit it to enter the
cutter head or block y'. The catch is then raised so as to release first the mandrel e
which is returned to its normal position under the action of the spring o, and then
the carrier, which is then turned to bring the mandrel or tool-holder el carrying
the finishing cutter in line with the rod or wire F. The said mandrel or tool-.
holder el is then moved forward, the latter and the carrier fare locked in position
as before and the movable head or saddle a is fed or moved forward until the rod
comes into contact with the wire or rod F. The end of the said wire or rod is thus
turned or shaped by the cutter block g'so as to finish the shank and form the head
of the screw.
In some instances the movable head or saddle a is retreated or moved backwards
after the first cut has been made by the cutter block g, or the second cut by the
cutter block g', or after both cuts, in order to clear away any turnings or obstructions
that may be adhering to the rod or wire F by drawing it through the bush i. (as.
shown in Figure 6).
To cut the screw threads the catch is again raised and the mandrel or tool-
holder e and carrier are released as before (the said mandrel being returned to
its normal position by its spring ) and the carrier is turned to bring the mandrel
or tool-holder e² carrying the screw cutting die opposite the wire or rod F and
is locked in position by the said catch. The said mandrel or tool-holder e² is then.
moved or pushed forward by means of the loose knob or handle e and is held from
rotating by the projection engaging with the feather and cuts a screw thread
upon the rod or wire F as shown in Figure 7. When however the said projection t³
reaches the bevelled or cut away portion the mandrel is released and revolves,
and upon the motion of the mandril C and wire or rod F being reversed is returned
to its normal position as hereinbefore described.
To separate or detach the finished screw from the wire rod or blank F the slide
rest is operated by means of the handle u² and screw-threaded spindle ' to form.
a cut in the said rod wire or blauk Fas shown in Figure 8.
The form of the upper portion or surface of the head of the screw is regulated
by the shape of the tool . In some instances another tool is also provided in the
second tool holder for this purpose.
In cases where it is desired to mill the head of the screw, the bent arm or lever w
is moved over so as to bring the milling tool or cutter ² into operation, previous to
cutting off the said screw.
To adapt the machine for cutting left handed screw-threads the ends of the ribs
or feathers on the collar or sleeve r are cut away or bevelled on their undersides.
or surfaces instead of on the upper surfaces thereof, and the projection t³ first
engages with and travels up the said under surface and returns along the upper
surface thereof. Suitable left handed cutter heads and screw die or dies are also
provided and the motion of the mandrel C and wire rod or blank Fare reversed.
In some instances we arrange one or more of the ribs or feathers on the block
rpiece for cutting left handed screw threads and one or more for cutting right

page_text: handed threads, thereby enabling the same block or piece to be employed for both
right and left handed screw-threads.
We find it most advantageous to mount the tool holders in a carrier adjustalile
about an axis parallel to the bed of the machine as hereinbefore described.
It is obvious however that they can be mounted with their axes in the same plane
in a carrier arranged to slide or move transversely to the said bed.
Although we have herein before described our improved.machine more particularly
with reference to the manufacture of screws it will be readily understood that it is
also advantageously applicable for the manufacture of other articles, such as for
instance nuts. In this case the tool-holders are fitted with suitable chucks or jaws
(instead of the hereinbefore described cutter-blocks and screw cutting die) adapted
to receive one or more drills and taps. We may employ any other convenient
number of mandrels or tool-holders, and the cutter heads or blocks, and screw
cutting dies, and drills, and taps or other tools may be of any suitable kind in.
accordance with the form of machine screw or other article which it is desired to-
manufacture.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we wish it understood that
we claim
First. A. machine for the manufacture of screws and other articles, wherein a
circular series of tool-holders is arranged to turn about an axis parallel to the bed
of the machine, for the purposes above specified.
Second. A machine for the manufacture of screws and other articles wherein two
or more longitudinally movable or adjustable mandrels or tool-holders are arranged
in a carrier which is supported in a longitudinally movable head or saddle, and
which is capable of adjustment relatively to the work for the purpose above
specified.
Third. The combination of an adjustable carrier supported in a longitudinally
movable head or saddle and provided with mandrels or tool-holders for the purposes
above specified, and a hollow or tubular rotary mandrel provided with a suitable
chuck or clamp for holding and rotating the rod or wire, substantially as hereinbefore
described.
Fourth. The combination, with the adjustable carrier for enabling the mandrels
or tool-holders to be consecutively brought into line with the work, of suitable
means for securing or locking the said carrier in either of the operative positions,
for the purposes above specified.
Fifth. The combination, with the longitudinally adjustable mandrel or tool-
holder, of suitable means for securing it in its operative position in the carrier, and
for automatically returning it to its original position when released, substantially
as, and for the purposes above specified.
Sixth. The combination, with the hollow or tubular adjustable mandrel or tool-
holder, of suitable means for regulating the length of the cut made by the tool,
substantially as described.
Seventh. The combination, with a longitudinally movable mandrel for holding a
screw-cutting tool, of an adjustable device whereby the rotation of the said tool with
the work will be permitted when but not until a screw-thread of the desired length
has been formed by the said tool, for the purposes above specified.
Eighth. The combination, with the transversely moving slide-rest, of the
adjustable stops for regulating the movement of the same, substantially as, and for
the purpose, set forth.
Ninth. The combination with the hollow or tubular rotary mandrel for holding
and rotating the work and the adjustable carrier provided with the movable or
adjustable mandrels or tool-holders, of a guide or support for the work, a pivoted
lever carrying a suitable milling tool or cutter and a transversely moving slide
rest, substantially as, and for the purposes, above specified.

page_text: Ninth. The improved machine constructed substantially as described with
reference to the accompanying drawings and operating as, and for the purposes,
hereinbefore specified.
Dated this 19th day of February 1891
HUBERT HENRY GRENFELL.
PETER BARON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicants.