Year: 1887

page_text: Date of Application, 3rd June, 1887
Complete Left, 5th Mar., 1888
Complete Accepted, 20th Apr., 1888
and other Articles.
I, EMILE DAVIS of 16 Camden Square London N.W. in the County of Middlesex
Engineer do hereby declare the nature of this invention (a communication to me
from abroad by Georg Heyne and Ernst Heyne trading as Heyne Brothers at
Offenbach on-the-Main, Germany) to be as follows:-
This Invention relates to improvements in the automatic lathe for turning screws
and screw-studs from a stock wire or rod and threading the same; for which Letters
Patent were granted to Frank Wirth dated January 27th 1882 No. 431; and the
invention consists-first, in the construction and operation of the screw-die holder,
whereby the necessity for great nicety of adjustment of the screw threading apparatus,
with regard to the cams and other operative parts of the machine is avoided, as the
die, after having cut a thread for the desired distance along the previously turned
screw or stud, is automatically released and permitted to revolve with the stock wire,
which may continue to turn in the same direction for some little time longer, the die
holder being adjustable so that the die will thus cease to cut a thread at any desired
point in the length of the screw and may be adjusted to cut the thread almost or quite
up to the head of the screw, or to a shoulder on the stem of the screw-stud, as the
case may be, without danger of jamming against the said head or shoulder. Further-
more, the die holder, when the direction of rotation of the stock wire is reversed, is
prevented from rotating, in order that it may be backed off or unscrewed from the
screw which it has just cut and is at same time brought into position for re-engage
ment with the head in which it is mounted, in order that it may return to its initial
position in readiness for operating on the next screw to be cut.
To effect these operations, the die holder is attached to the end of a spindle which is
fitted to slide in a guide tube or socket mounted adjustably in a head carried by the
slide rest. The die holder spindle is connected to the guide tube or socket by a key,
sliding in a longitudinal key-way in the latter, whereby as long as the key remains
in the said key way the die will be prevented from rotating. The die-holder is forced
backwards by a spiral spring confined between shoulders on its spindle and socket the

page_text: pressure of this spring being however, overcome in the first instance by the cam
whereby the die is brought up to and caused to engage upon the work, and afterwards
by the die drawing its holder forward, as the cutting of the screw progresses. This
forward motion continues until the key is drawn out of its key way, whereupon the
die holder is free to rotate as above mentioned. At the rear end of the die holder
spindle, is a spring catch which when the motion of the die holder begins to be
reversed by the reversal of the motion of the stock rod or wire engages with a lug
on the rear end of the guide socket and so holds the die holder stationary, to cause
the die to back or unscrew itself off the screw it has just cut. In this position of
the die holder, the key above mentioned is in alignment with the key way in the
guide socket, so that it will at once enter the same, on the die becoming unscrewed
from the stock rod, whereupon the die holder is moved back to its normal position by
the spring above mentioned. The key is not rigidly attached to the die holder spindle,
but is free to slide in a longitudinal slot therein and is drawn back by another spiral
spring within the die holder spindle, so that should it be prevented by any cause from
at once re-entering its key-way, the spring will yield and allow the die holder to be
nevertheless returned by the spring first mentioned, and so moved out of the way of
the other tools.
The Invention relates secondly, to an improved construction of chuck for rotating
the stock wire and presenting it to the action of the tools. This chuck consists of
radially sliding dogs or jaws fitted in mortises in the body of the chuck and forced
outwards by spiral springs contained within the said mortises, and inwards by levers
provided with adjusting screws which bear on the outer ends of the dogs, the levers
being mounted on the body of the chuck and actuated by a sliding collar upon the
hollow mandrel, which comes between the other ends of the levers and forces them
outwards.
E. DAVIS.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: I, EMILE DAVIS, of 16, Camden Square, London, N.W. in the County of Middlesex,
Engineer, do hereby declare the nature of this invention (a communication 'to me
from abroad by Georg Heyne and Ernst Heyne, trading as 'Heyne Brothers; 'at
Offenbach on-the-Main, Germany) and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:
This Invention relates to improvements in the automatic: lathe for turning screws
and screw-studs from a stock wire or rod and threading the same for which Letters
Patent were granted to Frank Wirth dated January 27th 1882 No. 431; and -the-
invention consists ;-first in the construction and operation of the-screw-die; holder
whereby the necessity for great nicety of adjustment of the screw threading apparatus,
with regard to the cams and other operative parts of the machine is avoided, as the
die after having cut a thread for the desired distance along the previously turned
screw-or stud is automatically released and permitted to revolve with the stock wire
and mandrel which may and generally would continue to be turned a few more revo-
lutions than are absolutely required for the length of screw thread to be cut, the die
holder being adjustable so that the die will thus cease to cut a thread at any desired
point in the length of the screw and may be adjusted to cut the thread almost for
quite up to the head of the screw, or to a shoulder on the stem of the screw stud, as
the case may be, without danger of jamming against the said head or shoulder.
Furthermore, the die holder when the direction of rotation of the mandrel and stock
wire is reversed, is prevented from rotating in order that it may be backed off or
unscrewed from the screw which it has just cui and is at same time brought into
position for re-engagement with the head in which it is mounted in order that
it may return to its initial position in readiness for operating on the next screw to
be cut.
The Invention relates secondly to an improved construction of chuck for rotating
the stock wire for the purpose of presenting it to the action of the tools.
.
Reference is to be had to the accompanying drawings forming part of this specifi-
cation wherein figure 1 is an end view and figure.2 a longitudinal vertical section of
the die holder, the screw die being omitted. Figure 3 is an underside view shewing
the die holder drawn out and free to be carried round by the mandrel and stock wire
so as to render the die inoperative when the desired length of thread has been cut.
Figure 4.is top plan, figure 5 a longitudinal vertical section, and figure 6 an elevation.
partly in section.(on line-1-1 figure 4) of the chuck for gripping the stock wire..
The same letters of reference indicate the same, parts in all the figures.
Referring to figures 1, 2, and 3, it will be seen that the operations of rendering-the

page_text: screw die inoperative at the proper moment and of causing it to be backed off the
screw when the motion of the stock wire is reversed and of returning the die to its
initial position in readiness for cutting another screw, are performed automatically.
To effect these operations, the die holder A is attached to the end of a spindle B
which is fitted to slide in a guide tube or socket C mounted adjustably in the head D
of a standard carried by the longitudinally movable slide rest, (described in the
specification of the aforesaid Letters Patent and therein indicated by the letter M).
The die holder spindle B is tubular and is connected to the guide tube or socket C by
a key E passing through a longitudinal slot b in spindle B and sliding in a longi-
tudinal key-way c in the guide C whereby as long as the key remains in the said key
way the die holder A will be prevented from rotating. The die-holder is forced
backwards by a spiral spring F confined between a shoulder formed by the end of a
cap piece B fixed on the spindle B, and a shoulder formed in the socket C, the
pressure of this spring being however overcome in the first instance by the action of
the cam and lever described in the specification of the previous patent aforesaid (and
therein respectively referred to by the letters A and,Z) which acting on the rear.end
of the spindle B bring the die up to and cause it to start a thread on the work as
described in the former specification, the. spring after the cam has ceased to act,
continuing to be overcome by the screw in process of formation drawing the die and
holder A forward as the cutting of the screw progresses. This forward motion of
the die and holder continues until the key E is drawn quite out of its key way e, as
shewn in figure 3, whereupon the die holder A B is free to rotate as above mentioned
in the direction of the arrow. In this position the key E is caused by a spring e
contained within the hollow spindle B and attached to the key at one end and at the
other end to a T headed hook made fast to the rear end of the spindle B to bear
against the front end of the socket C. This end of the socket is in the form of a
spiral incline terminating in a shoulder c' against which the key E. abuts, as shewn
in figure 3, when the notion of the die holder A begins to be reversed by the
reversal of the motion of the stock rod or wire whereby the die holder is held
stationary in order to cause the die to back or unscrew itself off the screw it has just
cut. In this position of the die-holder the key E is in alignment with the key way c
in the guide socket (so that it will at once enter the same, on the die becoming
unscrewed from the stock rod whereupon the die holder A B is moved back to its
normal position by the spring F. The key is free to slide in the longitudinal- slot >>
in the spindle B so that the screw. die will not be forced forward by the spirally
inclined end of the guide socket C and should the key be prevented by any cause
from at once re-entering its key way c the spring e will yield and allow the die
holder to be nevertheless returned by the spring and so moved out of the way of
the other tools. The guide socket is clamped in position in the head D by means
of a screw and is longitudinally adjustable therein according as the screw is to be
threaded up to the head or shoulder of the screw, or to any less distance. The
spindle B is not accurately fitted in the guide socket C but has a certain amount of
looseness or play to enable the die to centre itself on the stock wire.
.
Referring now to figures 4, 5, and 6, G is the stock wire, H the hollow mandrel,
and 1 the body of the chuck for gripping and rotating the stock wire. This chuck
consists of radially sliding dogs or jaws K fitted in mortises in the body 1 of the
chuck which is fast on the mandrel H, the jaws being pressed outwards by spiral
springs contained within cavities in the body I alongside the jaws, the springs
bearing against lugs on the jaws. The jaws are forced inwards by levers L
provided with adjusting screws which bear on the outer ends of the dogs K, the
levers being pivoted at on the body I of the chuck, and oscillated simultaneously
by a sliding collar M upon the hollow mandrel H, which is moved to and fro along
the mandrel (by a forked lever actuated by a cam as described in the specification
of the previous patent aforesaid) so as at the proper times to bring the larger or
smaller part of the collar between the friction rollers at the tail ends of the levers, and
thus force the dogs inwards to grip the wire or release them to allow the wire to be -
fed forward, as the case may be.
F

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In an automatic lathe or machine for making screws from a stock wire or rod,
the combination of mechanism comprising the sliding die holder, its guide socket, the
key connecting them and their adjuncts whereby after the desired length of thread
has been cut the die holder is automatically released and permitted to revolve, and
whereby on the motion of the wire being reversed the die is caused to back off from
the screw and is returned to its initial position, substantially as specified.
2. In an automatic lathe or machine for making screws from a stock wire or rod,
the chuck for rotating the stock wire, consisting in the combination of radially sliding
dogs or jaws, levers provided with adjusting screws, sliding collar for operating the
jaws in one direction, and springs for forcing them outwards, the whole applied to a
hollow mandrel as and for the purpose specified.