IMPROVEMENTS IN MACHINERY FOR MAKING WOOD SCREWS
Year: 1857

page_text: LETTERS PATENT to John Talbot Pitman, of the American & European
Patent Office, No. 67, Gracechurch Street, London, for the Invention
of "IMPROVEMENTS IN MACHINERY FOR MAKING WOOD SCREWS."-A com-
munication from a citizen of the United States.
Sealed the 22nd December 1857, and dated the 25th June 1857.
PROVISIONAL SPECIFICATION left by the said John Talbot Pitman at
the Office of the Commissioners of Patents, with his Petition, on the
25th June 1857.
I, JOHN TALBOT PITMAN, of the American & European Patent Office,
No. 67, Gracechurch Street, London, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MACHINERY FOR MAKING WOOD SCREWS;"
a communication from a citizen of the United States, to be as follows:-
It consists in a combination of devices for feeding, pointing; and threading
screw blanks.
I employ for feeding the blanks a jointed segmental elevator, vibrating
through a slot in the bottom of the feed pan or hopper in which the blanks
are held. This elevator when down even with the bottom of the pan receives
the blanks, and when rising delivers them into fixed' ways or guides, whence
they descend to a carrier, which is vibrated from a vertical to a horizontal
position by means of an arm operated by a cain, and controlled in its move-
ments by a curved slotted guide piece. The carrier, when in the horizontal

page_text: position, delivers the blank to the nippers, which hold it while it is being
pointed and threaded, both which operations are performed by the same tool.
During the pointing the tool or cutter is moved lengthwise of the blank by
means of a cam actuating a lever which moves the tool holder. The tool is
brought toward and from the blank by means of projections or risers on
a cam wheel operating the arm or lever to which the tool is attached. The
motion of the tool in threading the blank is independent of the pointing
motion, being communicated to the tool by means of a leader worm, which
at proper intervals gives lateral motion to the shaft to which the tool holder
is attached by means of a catch wheel and spring paul operated by a spring
and chain. When the threading is completed, the lower end of the arm or
lever to which the tool is attached falls into a recess in the cam wheel,
thereby withdrawing the tool out of the way, so that the screw may be
dropped from the nippers by any usual mode. The movements of the
machine arc effected by usual mechanical means, all of which will be fully
explained in my Final Specification.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Talbot Pitman in the Great Seal Patent Office on the
24th December 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TALBOT PITMAN, of the American & European Patent Office, No. 67, Grace-
church Street, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of June, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Talbot Pitman, Her special licence that I, the said John Talbot Pitman,
my executors, administrators, and assigns, or such others as I, the said John
Talbot Pitman, 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 MACHINERY
POR MAKING WOOD SCREWS," a communication, upon the condition (amongst
others) that I, the said John Talbot Pitman, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and seals,

page_text: 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 John Talbot Pitman, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
For feeding the blanks I employ a jointed segmental elevator A, vibrating
up and down through a slot B in the bottom of the feed pan C. This
elevator is hung upon the shaft D, and operated by means of the slotted
arm E on shaft D, and pin F on the vibrating arm G, which arm, having its.
centre of motion at a, is vibrated by a projection on its lower end working in
the cam H. When the elevator is down its upper edge lies even with or just
below the bottom of the pan, and the blanks fall into the trough K of the
elevator and catch or hang by their heads, the heads being wider than the
trough. As the elevator is raised it carries up a supply of blanks, and when
sufficiently elevated the blanks slide into the fixed ways L, whence they
descend one by one into the carrier, this part of the operation being regulated
by meaus common to screw machinery, and not, therefore, necessary to be
described. The carrier 6 vibrates upon the axis c at the upper extremity of
the arm M, which arm is operated by cam N on the wheel P. The requisite
motions of the carrier for conveying the blanks to the nippers m are effected
by means of the curved slotted guide piece R, which is attached to and turns
with the axis of the carrier and the stationary pin n. It will be readily seen
that, as the arm M vibrates back and forth, the curved slot of the piece R
will be drawn over the pin n (shewn in Fig. 4), and move the carrier 6 from
the vertical to a horizontal position. During the pointing of the blank the
tool is moved lengthwise of the blank by the side cam a acting on lever Y,
and during the threading by the leader worm T. The threading and pointing
tool S, attached to the upper part of arm S¹, is moved towards the blank by
the action of the risers e, c, c¹, of cam wheel P upon the lower end of arm Ş¹,
and from the blank by the action of the spiral spring &, upon the arm S¹, in
conjunction with the recesses e³, e, e, in the periphery of the wheel P.. The
risers e, e, e¹, are raised on their outer edges, as shewn in Figs. 1 and 2, and
the form given to the periphery of these risers corresponds to the form of the
point of the blank. The axis of the leader worm wheel T has its bearing in
the enlargement Z of the shaft A', said bearing being adjustable by means of
the sliding box B¹. Fixed to the lower end of the axis of the worm wheel,

page_text: and revolving with it, is a catch wheel C',provided with a suitable number
of stops (six in this case) to be caught by the spring pawl D', pivoted to the
enlargement Z of shaft A'. The revolution of the leader shaft W causes the
worm wheel T and the catch wheel C' to revolve until the stops of the catch
wheel are arrested by the spring pawl D', when the rotary motion ceases, and
by the action of the leader upon the worm, the worm, catch, pawl, enlarge-
ment, and shaft A' all move in the direction of the length of the shaft,
carrying the threading tool along the blank to cut the thread. Supposing
a screw blank to have been taken by the nippers from the carrier, the
pointing is first to be effected as follows:-During the revolution of the wheel
P, when the inner and lowest part of the riser e comes into contact with the
set screw S² in the arm S¹, it acts upon the arm so as to depress the tool and
bring it into contact with the blank for the purpose of commencing the
operation of cutting the point. As the wheel P continues to revolve in the
direction of the arrows, sliewn in Fig. 1, the action of the side cam X upon
the lower end of lever Y forces its upper end against the collar T on the
shaft A', and moves the shaft carrying the tool and lever S¹ end wise towards
the end of the blank, and thus carries the set screw S2 on to the raised.
portion of the riser e. The effect of this movement is to gradually depress
the point of the tool towards the axis of the blank, and thereby cut the blank
to a point. During the operation of pointing, the inner end of the spring
pawl D¹ is kept from contact with the catch wheel C¹ by means of the chain
E attached to the upper end of the lever Y and to the inner end of the
pawl, so that the worm wheel T, being allowed to revolve on its own axis,
does not operate to lead or move the shaft A¹ lengthwise. The lengthwise
motion of the tool during the pointing is thus effected by the cam X and
Jever Y, independently of the means for effecting the lengthwise motion of the
tool during the threading operations. As the lengthwise motion of the tool
during the pointing of the blank must be slower than it is during the cutting
of the thread, the two motions must be independent of each other, and the
cam X is so shaped as to give the required rate of motion to the tool for
pointing the blank. When the pointing is completed, the lever Y passes off
from the cam X as the wheel P revolves, and the spring pawl P¹ attached to
the framework of the machine and the enlargement Z of the shaft A¹ pulls
the shalf A¹ back, and brings the tool in position to commence the threading
operation, at the same time the chain E' is slackened, and allows the spring
D to force the inner end of the pawl into contact with the catch wheel C.
The lengthwise motion of the tool for threading is effected as follows:-The
revolution of the worm-wheel T being stopped by the action of the pawl upon

page_text: the catch wheel C¹, which, as before said, is fastened to the axis of the worm
wheel, and revolves and stops with it, the threads of the leader shaft acting
upon the worm move the shaft A¹ lengthwise, carrying the tool along the
blank to cut the thread. When the tool has cut the thread to the point, the
outer end of the pawl D¹, .by coming into contact with the stop h, releases
the inner end from the catch wheel, and the spring P¹ again pulls back the
tool with its shaft A' into position to commence another threading operation.
This operation may be repeated as many times as may be necessary to cut
a full thread. Aceording to the Drawings herein referred to there are pro-
visions shewn for passing the tool over only twice in the threading operation.
In order to cut the thread the tool is brought into contact with the blank by
means of the risers e and e¹ acting successively upon the lever S¹; the riser e',
which operates to make the second cut, being a little more raised than the
riser e, causes the tool to cut deeper into the blank. These risers are similar
in form to the riser e, which operates in cutting the point, their outer edges
being raised to operate upon the tool, so as to cut the thread down to the
point. When the threading is completed, the lower end of the lever S¹ falls
into the recess e, thereby withdrawing the tool out of the way, so that the
screw may be dropped from the nippers by any of the usual modes known and
used in screw machinery.
What I claim is the jointed elevator passing through the bottom of the
feed pan, substantially as set forth.
I claim the vibrating slotted guide piece fixed to the carrier shaft, operated
by arm M and pin N, as herein set forth.
I claim giving the threading tool, for the purpose of pointing the blank, a
motion independent of and slower than that required to effect the threading,
as set forth.
I claim the catch wheel C, with its pawl and stop, in combination with the
leader worm T, as set forth.
In witness whereof, I, the said John Talbot Pitman, have hereunto set
my hand and seal, this Twenty-third day of December, in the year of
our Lord One thousand eight hundred and fifty-seven.
JOHN TALBOT PITMAN. (L.S.)