IMPROVEMENTS IN MACHINERY FOR CUTTING WOOD SCREWS AND SLOT BOLTS
Year: 1870

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery
Lane, in the County of Middlesex, Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN MACHINERY FOR CUTTING WOOD SCREWS AND
SLOT BOLTS."-A communication from abroad by Louis André de
Coster, Joseph Michel Melany, and Edward Casper, all of 13,
Boulevart St. Martin, Paris.
Sealed the 11th November 1870, and dated the 25th May 1870.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 25th May 1870.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN MACHINERY FOR CUTTING WOOD
SCREWS AND SLOT BOLTS," to be as follows:-
The machines heretofore invented for cutting wood screws and slot
bolts may be divided into two classes, viz., those requiring manual
assistance and those which are entirely self-acting.
The improved machinery of this Invention is based on the principle
of those operated by hand, but is entirely self-acting.

page_text: Figure 1 of the accompanying Drawings is a part sectional longi-
tudinal elevation; Figure 2, an end view, and Figure 3, a section of the
machine on the line 1-2, Figure 1. In all these Figures the same letters
of reference indicate like parts.
The machine consists of a headstock A with front and rear sole
plates B and C cast in one piece with a base D forming the bed of the
machine. This base contains a drawer d placed under the cutting tool
to receive the soapsuds used in the threading of the screws and the
whole may be placed either on a bench or on cast-iron standards. The
headstock A carries a shaft E receiving rotary motion through fast and
loose pulleys F, F, and also a longitudinal motion by means of a leading
or guide screw G gearing when required with a guide H. The shaft is
provided with a chuck I, to which are jointed jaws A³, A¹, for holding
the screw to be cut operated by a gland J, a support K being also pro-
vided for the screw to rest upon when the tool E¹ is brought down to
cut a thread thereon. The stems or bolts to be screw threaded are
supplied through a slide M whence they pass one by one into a receiver N
having a stop o¹ for regulating their passage. This receiver N is capable of
being moved transversely to bring it opposite the end of shaft E¹ when
rodo (the length of which may be regulated according to the length:
of the stem or bolt) moves forward within the receiver and pushes the
said stem contained therein into the shaft E which is hollow throughout.
The stems or bolts drive each other forward until they reach the
chuck I where they are gripped, as before mentioned. The sole plate
B supports a slide P carrying an obliquely slotted plate R for a
operating a forked lever arm S mounted at its lower end on pivots b, b¹,
the upper end being forked to embrace the gland J for closing the
jaws A', A¹. The bearing K is carried on an extension of the framing
and is capable of sliding thereon to allow of the tool E¹ being adjusted
to out corame of remiave longtha
The headstock A is provided with two arms supporting a shaft U to
which is keyed the lever tool carrier V. At one end of this shaft a crank
arm c similar to that c¹ herein-after referred to is provided for imparting a
to-and-fro movement to a slide D by means of a connecting rod e. This
slide moves transversely, and in it is formed an oblique slot f in which
works a friction roller g carried on a stud h connected to a link k, by

page_text: which lever i is oscillated on its fulcrum to bring forward the holder j of
the rod o for conveying the stems or bolts through shaft E. Above the
slide D is another slide D₁ carrying the receiver N, the two slides being
connected by means of a spring catch. This catch is raised at a given
moment by an inclined part by which it is disengaged when the receiver
is brought opposite the shaft and during the movement of the push rod.
It will be seen by the arrangement above described that when the
slide reaches the end of its course it gears the guide H with the guide
screw G, thus compelling the shaft E to move in a longitudinal direction
as it rotates when the guide screw leaves the guide, the receiver N is
brought opposite the end of the shaft, and the push rod forces the bolts
or stems forward to the jaws. The clamping of the jaws A is effected
by means of the crank arm c¹ on the shaft U (Figures 2 and 3) which is
connected to slide P and imparts a to-and-fro movement thereto for
operating the gland J through the medium of slotted plate R and
lever S, as before described. On the release of the jaws the shaft E
which is held up to the part K by a spring X, Figure 1, has a tendency
to return, to prevent which, an arm Z on shaft U takes into a groove P¹
formed in shaft E, so that longitudinal movement of said shaft is pre-
vented, although it is still free to revolve. It is when in this position
that the jaws are released.
From the foregoing description it will be seen that by raising the
lever tool holder V I partially rotate the shaft U which controls the
movements of the two slides, and thereby according to their positions
effect, first, the throwing out of gear of the guide screw motion.
Secondly, the return of the shaft E to its original position. Thirdly,
securing the shaft in position by the aid of arm Z. Fourthly, the release
of the jaws. Fifthly, the placing of receiver N opposite the end of the
shaft. Sixthly, the expulsion by means of rod o of the finished screw,
which is replaced by a fresh stem. On the contrary, by lowering or
depressing the lever V such operations are produced inversely. There-
fore, if I control the vibrations of this lever by means of a cam or tappet
receiving its motion from the driving shaft E I produce a self-acting

page_text: of its faces. This wheel receives its motion from a combined ratchet
wheel and pinion 6, running loose on the shaft U, motion being
imparted to the ratchet wheel by a double-acting spring pawl 8
actuated by an eccentric on shaft E with a groove and feather con-
nection between the two to permit of the longitudinal motion of the
shaft. Upon shaft U and in front of cams 4, 5, is keyed a counter-
balance lever 9, the end of which carries a tappet bearing on said cams.
This counterbalance lever maintains a steady contact of the tappet with
the cams by which it is always controlled. The cam 5 is furnished with
four, five, six, or seven concentric parts, according to the kind of screws
to be produced and which require te be operated on several times. Each
one of these cam surfaces terminates in a notch or recess in which
the tappet enters during the motion of the cam, and thereby determines
the motion of the shaft U, and consequently the throwing out of gear
of the guide screw motion and the return of the shaft to its original
position, as herein-above described. The second cam 4 is provided with
an equal number of parts, being inclined planes, in coincidence with the
concentric parts of the first cam. These inclined planes project beyond
the cam surfaces 5 and so compel the tappet to rise, and thus depress
the tool to form the point. The position of the second cam in reference
to the first may be adjusted at will by means of two bolts 12 and 13.
These cams are also provided with spaces x which permit lever 9 to
describe a quarter revolution, and thus to effect the changes above
mentioned. The cam 5 is also provided with a friction roller 10 which
in its motion acts on the end of the counterbalance lever and returns
it to its original position.
If desirable I may employ a counter cam in lieu of the counterbalanced
lever, and I may also provide the machine with a second cutting tool
specially adapted to form the point.
The features of improvement are, first, the arrangement of machine,
the principle of which is the fixedness of the tool and the motion of
the screw enabling me to obtain a simple machine.
2ndly. The new and peculiar arrangement for clamping and dis-
connecting the jaws,
3rdly. The backward motion which enables me to feed stems of any
length to the machine.
4thly. The automatical or self-acting motion which furnishes the
means of cutting any length of screw thread whatever may be the length

page_text: of such screws without making any alterations to the machine or adding
anything to the same because by taking one, two, or three teeth
from I revolve the cam one, two, or three times faster, and thus I
obtain with the same cam the means to cut screws one, two, or three
times faster.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal
Patent Office on the 24th November 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of May, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, admi-
nistrators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 FOR CUTTING WOOD SCREWS AND SLOT BOLTS,"
a communication to me from abroad by Louis André de Coster, Joseph
Michel Melany, and Edward Caspar, all of 13, Boulevart St. Martin,
Paris, upon the condition (amongst others) that I, the said Alexander
Melville Clark, 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.

page_text: NOW KNOW YE, that I, the said Alexander Melville Clark, 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, reference being had to the two
Sheets of Drawings hereunto annexed and to the letters and figures
marked thereon (that is to say) :—
The machines heretofore invented for cutting wood screws and slot
bolts may be divided into two classes, viz., those requiring manual
assistance, and those which are entirely self-acting.
The improved machinery of this Invention is based on the principle
of those operated by hand, but is entirely self-acting.
Figure 1, of the accompanying Drawings, is a part sectional longitudinal
elevation; Figure 2, an end view; and Figure 3, a section of the machine
on the line 1-2, Figure 1. In all these Figures the same letters of
reference indicate like parts.
The machine consists of a headstock A with front and rear plates B
and C, all cast in one piece with a base D forming the bed of the
machine. This base also contains a drawer d placed under the cutting
tool to receive the soapsuds used in the threading of the screws, and
the whole may be placed either on a bench or on cast-iron standards.
The headstock A carries a shaft E, receiving rotary motion through fast
and loose pulleys F, F, and also a longitudinal movement by means of
a leading or guide screw G gearing when required with a guide H.
The shaft is provided with a chuck I to which are jointed jaws A¹, A³,
for holding the blank bolt to be cut, operated by a collar J, a support K
being also provided for the blank to rest upon when the tool E¹ is
brought down to cut a thread thereon. The blank stems or bolts are
supplied through a slide M whence they pass one by one into a
receiver N having a stop o¹ for regulating their passage; this receiver N
is capable of being moved transversely to bring it opposite the end of
shaft E, when rod O (the length of which may be regulated according to
the length of the stem or bolt) moves forward within the receiver, and
pushes the said stem contained therein into the shaft E, which is hollow
throughout. The stems or bolts drive each other forward until they
reach the chuck I, where they are gripped by the jaws A¹ as before
mentioned. The plate B supports a slide P carrying an obliquely
slotted plate R for operating a forked lever arm S, mounted at its lower
end on pivots b, b, the upper end being forked to embrace the collar J

page_text: for closing the jaws A', A¹. The bearing K is carried on an extension
of the framing, and is capable of sliding thereon to allow of the tool E¹
being adjusted to cut screws of various lengths.
The headstock A is provided with two brackets supporting a shaft U,
Figures 2 and 3, to which is keyed the lever tool carrier V. At one end of
this shaft a crank arm c is provided for imparting a to-and-fro movement to
a slide D¹ by means of a connecting rod e. This slide moves transversely,
and in it is formed an oblique slot fin which works a friction roller g
carried on a stud h connected to a link k by which lever i is oscillated
on its fulcrum to bring forward the holder j of the rod O for conveying
the stems or bolts through shaft E. Above the slide D' is another
slide D", carrying the receiver N, the two slides being connected by
means of a spring catch. This catch is raised at a given moment by
an inclined part by which it is disengaged when the receiver is brought
opposite the shaft, and during the movement of the push rod. When
the slide reaches the end of its course the projection p thereon comes
into contact with the lever arm q of the guide H which is thus geared
with the guide screw G compelling the shaft E to move in a longitudinal
direction as it rotates, and when the guide screw leaves the guide the
receiver N is brought opposite the end of the shaft, and the push rod
forces the bolts or stems forward to the jaws. The clamping of the
jaws A is effected by means of the crank arm c' on the shaft U
(Figure 2) which is connected to slide P, and imparts a to-and-fro
movement thereto for operating the collar J through the medium of
slotted plate R and lever S as before described. The releasing of the
jaws has a tendency to move back the shaft E which is only held up to
the part K by a spring X, Figure 1, to prevent which an arm Z on
shaft U is caused to take into a groove P¹ formed in shaft E, SO
that longitudinal movement of said shaft is prevented although it is
still free to revolve. It is when in this position that the jaws are
released.
From the foregoing description it will be seen that by raising the lever
tool holder V I partially rotate the shaft U which causes the movement
of the two slides, which thereby according to their positions effect
first, the throwing out of gear of the guide screw motion. Secondly, the
return of the shaft E to its original position. Thirdly, the movement of
arm Z to hold the shaft in position. Fourthly, the release of the jaws.
Fifthly, the placing of receiver N opposite the end of the shaft. Sixthly,

page_text: the expulsion by means of rod O of the finished screw which is
replaced by a fresh stem. On the contrary, by lowering or depressing
the lever V such operations are produced inversely. Therefore, if I
control the vibrations of this lever by means of a cam or tappet
receiving its motion from the driving shaft E, I produce a self-acting
machine.
X¹ is an iron bearing or support secured to the headstock A by
studs 1, 2, and carrying a spur wheel Y, having cams 4, 5, on one of its
faces. This wheel receives its motion from a combined ratchet wheel
and pinion 6 running loose on the shaft U, Figuro 3, motion being
imparted to the ratchet wheel by continuous acting spring pawls 8,
carried on a slotted lever 7 actuated by an eccentric 3 on shaft E, with a
groove and feather connection between the two to permit of the longi-
tudinal motion of the shaft. Upon shaft U and in front of cams 4, 5,
is keyed a counterbalance lever 9, the end of which carries a tappet
bearing on said cams. This counterbalance lever maintains a steady
contact of the tappet with the cams by which it is always controlled.
The cam 5 is furnished with four, five, six, or seven concentric parts
according to the kind of screws to be produced, and which may require
to be operated on several times. Each one of these cam surfaces termi-
nates in a notch or recess in which the tappet enters during the motion
of the cam and thereby determines the motion of the shaft U, and
consequently the throwing out of gear of the guide screw motion, and
the return of the shaft E to its original position as herein-above described.
The second cam 4 is provided with an equal number of parts, being
inclined plancs in coincidence with the concentric parts of the first cam,
these inclined planes project beyond the cam surfaces 5, and so compel
the tappet to rise and thus depress the tool to form the point. The
position of the second cam in reference to the first may be adjusted at
will by means of two bolts 12 and 13. The cams are also provided with
spaces which permit lever 9 to describe a quarter revolution, and thus
to effect the several changes above mentioned. The cam 5 is also
provided with a friction roller 10, which in its motion acts on the end
of the counterbalance lever and returns it to its original position. By
varying the position of the eccentric rod in the slotted lever 7 the
pawls may be made to move the ratchet one, two, or more teeth at a
time, so as to move the cam at a greater or less speed. Thus with one
cam I am enabled to cut screws both faster and shorter.

page_text: If desirable I may employ a counter cam in lieu of the counterbalance
lever, and I may also provide the machine with a second cutting tool
specially adapted to form the point.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention
to be protected by the herein-before in part recited Letters Patent,
is,―
1st. The arrangement of screw cutting machine in which the bolt
to be cut is moved longitudinally, whilst under the action of a
stationary cutter, all as herein-before described and illustrated in the
Drawings.
2ndly. I claim the combination and arrangement of parts constituting
the apparatus for effecting the opening and closing of the jaws A¹ at the
proper moment, operating substantially as described and shown in the
Drawings.
3rdly. I claim the arrangement of feed apparatus for supplying blank
bolts of different lengths to be cut, operating substantially as shown and
described.
4thly. I claim the arrangement of apparatus for enabling the machine
to cut screws of various lengths and pitch, operating substantially as
described and illustrated in the Drawings.
5thly. I claim the arrangement of adjustable counter cam for
pointing screws of different lengths, substantially as shown and
described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-fourth day of
November, in the year of our Lord One thousand eight hundred
and seventy.
0 Witness,
Wч. CLARK,
53, Chancery Lane.
A. M. CLARK. (L.S.)