Year: 1887

page_text: I, JOHN HASKINS LADD, of 116 Queen Victoria Street in the County of Middlesex,
Manufacturer 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 stateinent :-
This invention relates to the class of machines in which screw-threads are formed on
screws or bolts by the subjection of the screw-blank or bolt-blank to the action of two
reciprocating dies, the faces of which are suitably ribbed, and which, by their motions
in rectilinear paths in relatively opposite directions, roll the screw-blank or bolt-blank
to and fro, and gradually impress or form a spiral groove therein.
In machines of this class as heretofore constructed, the formation of the spiral
groove in the body of the blank is accompanied by a radially outward flow of the
metal displaced in forming the groove, with the result that, when the thread is formed,
its outside diameter exceeds the original diameter of the blank.
The object of the present invention is to cause the whole or nearly the whole of the
metal which is displaced during the formation of the spiral groove in the body of the
blank, to flow in a direction parallel with the axis of the blank, instead of flowing
radially outward, so that the diameter of the thread, when formed, will be the same as,
or only slightly greater than, the original diameter of the blank, and the screw-
threaded part of the blank will be elongated by the action of the dies.
To this end, the said invention comprises the employment of end wise reciprocating
straight dies, having opposed convex working surfaces, and means for imparting to
each of the said dies, during its end wise movement, while the screw-thread is being
formed, a prescribed range of slow rocking movement upon its longitudinal axis. The
working surfaces of the dies respectively are provided with series of oppositely-
inclined parallel ribs, and, if desired, portions of their surfaces adjoining those which

page_text: are convexly curved may be oppositely curved to adapt them for forming a gimlet-
point upon the end of the screw-blank subjected to their action. The range of rocking
movement of the dies is graduated with reference to enabling the dies to form
successively a prescribed number of convolutions of thread upon the body of the
blank upon which they are to act.
The said invention, moreover, comprises certain peculiarities in the mechanism for
automatically feeding the blanks successively to the dies.
In the accompanying drawings, I have shewn a machine embodying the present
improvements.
Figure 1 is a plan or top view of the said machine.
Figure 2 is a longitudinal vertical section on the line a, a, Figure 1.
Figure 3 is an end elevation, showing the mechanism for imparting the rocking
motions to the dies.
Figure 4 is a transverse vertical section on the line y, y, Figure 1.
Figure 5 is a side elevation of the said machine.
Figure 6 is a side elevation, partly in section, of the mechanism for delivering the
blanks successively, shewing the deliverer in the position in which it comes to rest at
the close of its backward movement, in the act of delivering a blank.
Figure 7 is a similar view, shewing the deliverer in the position in which it comes
to rest at the conclusion of its forward movement.
Figure 8 is a plan or top view, partly in horizontal section, shewing the deliverer
and adjoining parts of the machine.
Figure 9 is a transverse vertical section of the reciprocating rocking dies, showing
the positions which they occupy relatively to each other, and to the blank, at the
commencement of the rolling operation, and
Figure 10 is a similar section of the dies, showing their portions relatively to cach
other, and to the blank, just before the conclusion of the said operation.
The working parts of the machine are mounted-upon a horizontal rectangular
table A supported at its opposite ends upon the standards A, A². This table is
provided with suitable slots to afford clearance for the moving parts of the machine.
Power to drive the machine is applied to the horizontal driving shaft B having its
bearings in boxes B1, B2. Upon its inner end, the said driving shaft is provided with
a crank-arm C which is linked, by means of the pitman C₁, to a collar C² on the
forward end of a spindle D, which, for the sake of convenience, will be herein called
the stem of the quick-moving die D¹. The collar C is mounted loosely upon the
stem D so that the die D' may rock upon its longitudinal axis.
The die D is somewhat larger in diameter than the stem D, and its bearing is a
semi-cylindrical groove, the lower half d of which is formed in the table A, and the
half d in the cap ເl.
upper
The driving shaft B has fixed thereon the small spur-wheel which is geared with
the spur-wheel & fixed on the counter-shaft E having its bearings in the boxes E¹, E².
The said spur-wheels are of such relative diameter that the counter-shaft will make
one revolution while the driving shaft is making two, three or more revolutions as may
be prescribed.
The counter shaft E has fixed thereon the scroll came which engages with the end
of the sliding bar el and imparts backward movement thereto, the forward movement
of the said bar being effected by the retracting spiral spring e². The bar e¹, at its
rear end, is coupled to the crank-pin which is adjustably secured in a radially-slotted
crank-arm fixed on the rocking cam-shaft F.
The cam-shaft Falso has fixed thereon the scroll cam F¹, which acts upon the lower
end of the rocking lever F2, the upper end of which bears upon the rear end of the
stem G of the slow moving die G¹.
The die G', like the die D', is a cylinder of larger diameter than its stem, and is
provided with a semi-cylindrical bearing, the lower half g of which is formed
in the edge of the laterally-adjustable plate II, and the upper half g in the edge of
the cap H secured to the said plate. The plate H is supported upon the horizontal
bed of the machine, and is adjusted thereon toward and from the die D¹ by means of

page_text: the horizontal adjusting screw h; it is to be rigidly secured in any position to which
it may be adjusted by means of the clamping screws h', h², which are provided with
large collars or washers and are passed through holes in the plate H and inserted into
the bed upon which the said plate rests. The holes in the plate H being made large
enough to provide for the required range of adjustment of the said plate.
Rocking movements are imparted to the dies by means of the cams I and K fixed
on the rocking cam-shaft F. These cams engage with the lower ends of the crank-
arms I, K, which are fixed, by means of set-screws, upon sleeves I2, K2, having their
bearings, respectively, in the horizontally adjustable box 13 and in the upper part K³
of the end standard A². The sleeves 12 and K2 are so splined or keyed upon the
stems D, G of the dies D, G, that, while the said stems rotate with the said sleeves,
they are free to move endwise therein.
By the appropriate rocking movement of the scroll cam F¹, slow endwise move-
ment is imparted to the die G, which continues during a prescribed number of back-
ward and forward end wise motions of the die D'. The return movement of the slow-
moving die G¹ is effected by the retracting spiral spring F3.
is
The forward end of the stem G is loosely inserted through the vertical arm of the
check and deliverer carriage L, as more clearly shewn in Figure 8. A screw
inserted in the end of the stem G and the edge of the head of this screw bears upon
the face of the arm 7. Thus the said carriage I is compelled to partake of the end-
wise sliding movements of the die G¹.
The mechanism for automatically feeding the blanks successively to the dies com-
prises the inclined ways M, down which the blanks, hanging by their heads, slide by
their own gravity; their descent being checked during the first portion of the
forward movement of the die G¹ by the bearing of the lowermost blank against the
side of the deliverer N, which, at that time, extends across the lower end of the inclined.
ways.
The deliverer N is a flat bar set up edgewise, and fitted to slide in horizontal
bearings or guide-ways in the carriage L.
As the die G¹ moves gradually forward pushing forward the carriage L, the check-
arm m attached to the carriage L is projected across the ways between the lowermost
blank and the blank next behind it, and serves to hold back the row of blanks in the
ways when the deliverer has been carried forward clear of the lower end of the
inclined ways. The lowermost blank then slides downward into the forward end of
the horizontal portion M¹ of the ways M where it stands in front of the end of the
deliverer.
It is necessary that the deliverer shall have a greater range of forward movement
than the die G, in order that it may be carried so far forward as to allow the lower-
most blank to drop in front of it. This is effected by means of the rocking lever n,
which, by means of the pin n', is pivotally attached to the carriage L, and which has
its upper end loosely engaged in the notch n² formed in the edge of the deliverer N.
The lower end of the rocker n projects into a rectangular notch formed in the edge
of the adjustable horizontal gauge-plate O, which is attached to the table as shewn in
Figures 6, 7 and 8, and is capable of adjustment thereon in a direction parallel with
the path of motion of the carriage L.
When the die G¹ and carriage L have been carried so far forward as to effect the
partial projection of the check-arm m across the ways M, the lower end of the rocker n
is brought into collision with the forward edge O' of the gauge-plate and is thereby made
to rock upon its axis, and, by the action of its upper end upon the deliverer N, to
impart such an increased range of forward movement thereto as to withdraw the front
end of the deliverer from the space at the lower end of the inclined ways, thus, as
before stated, permitting the lowermost blank to drop into the horizontal part of the
ways, immediately in front of the deliverer.
During the quick return movement of the die G¹, the deliverer is carried back-
ward across the lower end of the inclined ways, pushing the blank before it toward
the space between the dies D', G¹.
As the carriage L moves backward, the lower end of the rocker n is brought into

page_text: collision with the rear edge 02 of the gauge-plate O, and, being thus compelled to rock
upon its axis in a direction opposite to that in which it has previously rocked, imparts
an increased range of backward movement to the deliverer, and carries the blank
against the slightly chamfered edge G2 of the die G¹. The blank arrives at this posi-
tion concurrently with the arrival of the die G₁ at its furthest backward position.
When the die G and the blank are in this position, the quick-moving die D¹ is in its
extreme forward position and is just ready to commence its backward movement.
By the backward movement of the die D¹, its rear edge is brought into collision
with the body of the blank, which is thereby caught and rolled along the surface of
the die G. While the blank is being thus rolled along the surface of the die G¹, the
latter is making a portion of its forward movement, so that, during the return or
forward movement of the die D', the blank will not be rolled far enough backward
to clear the forward end of the die G₁. The blank is rolled to and fro along the face
of the die Gas many times as the die D', and, at the end of the last backward move-
ment of the die D', the blank is rolled off the rear end of the die G¹.
It will be understood that the die G¹ is herein called the slow-moving die merely for
convenience of distinguishing it from the die D¹, which reciprocates two or more
times while the die Greprocates once.
The working portions of the faces of the dies D₁, G are each provided with a series
or system of parallel ribs which extend spirally along the faces of the dies in relatively
opposite directions.
During the to-and-fro rolling movements imparted to the blank, the dies are
gradually rocking upon their longitudinal axes and the convolutions of the
thread are thus being successively formed upon the body of the blank.
When the machine is to be used for rolling the threads of machine-screws, the
working surfaces of the dies are made concentric, respectively, with the axes upon
which they rock; but, if the dies are to be adapted for rolling the threads of gimlet-
pointed screws, the dies are respectively provided with the concentric portions P and p,
which are each provided with the systems of parallel ribs for forming the thread on
the body of the blank, and are also provided with the projecting portions P₁, p¹ in the
surfaces of which are formed ribs for acting upon the end of the blank, and thus
forming the gimlet-point, as shewn in Figures 9 and 10.
It will be seen that the convolutions of the thread of a blank are, in this machine,
formed successively, instead of being formed simultaneously, as they are in machines
wherein the blank is rolled between the opposed surfaces of two flat dies which act
simultaneously upon the entire portion of the body to be threaded.
By the above-described construction and arrangement of the feeding mechanism,
the necessity of employing a cam for operating the check is obviated; for, as will be
seen, the motions of the check and deliverer are borrowed from the slow-moving die G¹.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed as communicated to me by my
foreign correspondent, 1 declare that what I claim is :—
First. A machine for the manufacture of screws, wherein ribbed dies each having a
rocking movement upon its longitudinal axis are employed, between which the blanks
are rolled and one of which has two or more reciprocating or to-and-fro endwise
movements imparted to it whilst the other die is making a single end wise movement,
for the purposes above specified.
Second. In a machine for the manufacture of screws, the employment of two end wise
reciprocating and rocking dies, the opposed surfaces of which are suitably curved, and
are provided with series or systems of parallel ribs extending spirally in relatively
opposite directions, respectively, means for imparting to one of the said dies two or
more to-and-fro end wise movements during the time occupied in rolling the thread
upon a blank introduced between the dies, moans for imparting to the other die one
to-and-fro endwise movement during the same time and means for imparting, during
the same time, to each of the said dies, first a prescribed range of slow rocking
movement upon its longitudinal axis in one direction, while the thread is being formed

page_text: upon the blank and then a quick return rocking movement in the opposite direction,
after the screw-threaded blank has been discharged, and while the dies are making
their concluding movements whereby they reach the relative positions which they are
required to occupy preparatory to the feeding of another blank into the spaces between
their working surfaces.
Third. The combination, substantially as set forth, of the endwise reciprocating and
rocking dies D', G₁ provided respectively with the stems D, G, the crank-arms IT, K',
loosely splined or keyed upon the said stems respectively, two suitably shaped cams
engaging with the ends of the crank-arms I¹, K' respectively, and mounted upon the
cam-shaft F, and means for appropriately moving the said cam-shaft and thereby
rocking the dies D', G¹ upon their longitudinal axes during their endwise reciprocating
movements.
Fourth. The combination, substantially as set forth, of the die G¹, the retracting
spring F³, the scroll cam F¹ mounted upon the cam-shaft F, the rocking lever F
bearing, at one end, upon the scroll cam F³ and, at the other end, upon the end of the
stem G of the slow-moving die G¹, and means for appropriately moving the said cam-
shaft and thereby imparting the required endwise reciprocating movements to the
die G¹ for the purpose specified.
Fifth. The combination, substantially as set forth, of the cam e mounted upon the
counter-shaft E, the sliding bar e', the retracting spiral spring e², the crank-arm f¹,
the crank-pin adjustably secured to the crank-arm, and the rocking cam-shaft F
having mounted upon it suitable cams for imparting rocking movements to the dies D',
G respectively, for the purpose specified.
Sixth. The combination of the endwise reciprocating die G¹, the carriage L, the
deliverer N provided with sliding bearings in the carriage L, the ways M M and the
endwise-reciprocating die D', substantially as, and for the purposes, set forth.
Seventh. The carriage L suitably connected with and partaking of the endwise
reciprocating motions of the die G', the deliverer N provided with sliding bearings in
the carriage L, the rocking lever n pivotally attached to the said carriage Land, at its
upper end, engaging with the deliverer N, in combination with the horizontally
adjustable gauge-plate O for catching the lower end of the rocking lever n during the
movements of the carriage Land thereby causing the rocking lever n to rock upon its
axis and impart to the deliverer N a range of motion greater than the range of inotion
of the carriage L, all substantially as, and for the purposes, set forth.
Eighth. The gauge-plate O, presenting one of its edges in a position in which it
intersects the path of motion of the rocking lever n, and means for horizontally
adjusting the said gauge-plate O, and thereby fixing the limit to the backward motion
of the deliverer N, in the act of delivering a blank to the dies, substantially as set
forth.
Ninth. The laterally adjustable plate H, and the cap H₁ secured thereto, affording
the concentrically-grooved bearing for the die G¹, means for horizontally adjusting the
plate H and cap H toward and from the die D', and means for rigidly securing
the plate H and cap H' to the bed upon which the said plate rests, in any position to
which they may be adjusted, substantially as, and for the purposes, set forth.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.