Improvements in Screw-threading Machines.
Year: 1888

page_text: Date of Application, 4th Sept., 1888
Specification Accepted, 12th Oct., 1888
Improvements in Screw-threading Machines.
my
I CHARLES DAKE ROGERS, of Providence, in the County of Providence, and State
of Rhode Island, United States of America, Mechanic, do hereby declare the nature of
invention for IMPROVEMENTS IN SCREW-THREADING MACHINES and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The machine forming the subject of my present invention relates to the class which
produces threads upon screws by the reciprocating action of grooved dies, by and
between which the screw-blanks are rolled, thereby compressing the metal and forcing
it laterally into the grooves of the dies.
My invention consists essentially in the novel manner of mounting and actuating
the thread-forming dies, combined with automatically operating feeding and blank
holding mechanisms.
The object of my improvement is to simplify the construction of screw-threading
machines of the class referred to; to that end I employ a pair of oppositely mounted
and reversely arranged grooved dies actuated by the main driving arrangement; the
blanks while being acted upon are so held and guided between movable jaws that
the proper relation of the several parts to the blanks is positively maintained. An
example of a machine arranged and adapted to automatically roll screw-threads upon
blanks is shown and claimed in my U. S. Patent No. 370,353 of September 20th, 1887.
In the annexed four sheets of drawings. Figure 1, sheet 1, represents a side view
of my improved screw-threading machine; a portion of said Figure being shown
in section, or broken away to show some of the interior parts, the section being taken
on the irregular line o o of Fig. 2. Fig. 2 is a plan view, a portion of the feeding
mechanism, &c. being omitted. Fig. 3, sheet 2, is a front end view of the machine.
Fig. 4 is a vertical transverse sectional view, taken on the irregular line A A of
Fig. 2. Fig. 5 is a similar view taken on line of Fig. 2, the die and holder not
being in section. Fig. 6, sheet 3, is a plan view, enlarged, in partial horizontal
section, showing the manner of mounting the die-carrier or crosshead. Fig. 7 is a
cross-sectional view of the guide or runway which conducts the blanks from the

page_text: hopper or reservoir to the receiver. Fig. 8 is a vertical sectional view taken through
the centre of the receiver, the same being located directly over the movable blank-
holding jaws, which latter extend down into the space which separates the thread-
forming dies. Fig. 9 is a transverse sectional view of the same, and showing a
number of blanks lying in the runway preparatory to being dropped singly into the
holding jaws. Fig. 10 is a sectional view, similar to that shown in Fig. 8, showing
the holding-jaws nearly closed and having a blank therein in position to be acteil
upon by the dies on their return stroke. Fig. 11 is a transverse sectional view of
the two dies and the respective holders and cross-heads in which they are secured.
Fig. 11 shows the manner of supporting the blanks between the dies. Fig. 12,
sheet 4, is a plan view of the checking-device, by means of which the blanks are fed
singly to the holding-jaws. Fig. 13 is a side view thereof, in partial section, and
also showing a blank held in position between the holding-jaws preparatory to being
acted upon by the advancing threading-dies. Fig. 14 is an end view of the same,
showing in addition the lower portion of the track communicating with the checking-
head. Fig. 15 is a plan view, reduced, of the checking device and the cam-plates
for actuating the holding-jaws. Fig. 16 is an end view of the same. Fig. 17 is a
plan view of the holding-jaws in the closed position. Fig. 18 is an enlarged plan
view of one of the cam-plates, the same being arranged to intermittently actuate the
checking-plate and the corresponding holding-jaw. Fig. 19 is a detached plan view
(reduced) of the cam-plate showing the arrangement of the several eams formed
therein. Fig. 20 is a side view of the same. Fig. 21 is a detached plan view of the
plate or cover fitted to receive the cam-plate, shown in Fig. 19. Fig. 22 is a
longitudinal sectional view of the same, taken on line a c, and Fig. 23 is a transverse
sectional view taken on line ww.
A description of the several devices embodied in the present machine, together
with their construction and operation, and including the joint operation is as
follows:-
By referring now to the drawings A, will be found to designate the bed or main
framing of the machine; the same being very strong and formed in one piece. The
arrangement being such that the screw-blanks are held vertically while being acted
upon by the two threading-dies which are reversely arranged and mounted in
die-holders or cross-heads working in opposite directions.
B B, designate the two cross-heads which are fitted to reciprocate in ways a formed
in the main frame. The length of these ways being somewhat greater than twice the
length of the cross-head. In Fig. 2 the cross-heads are represented as being at the
extreme of travel, and preparatory to engaging a screw-blank. The upper part of
said ways are formed by gib plates a', secured to the bed. By this arrangement the
cross-heads are forced to travel in a true plane; the broad base and sides thereof
ensuring great rigidity or stiffness in action.
Each of the thread-forming dies D, is mounted in an L-shaped seat which in
turn is adjustably secured to the cross-head by bolts a³ a clamping-plate, a²,
resting upon the die and cross-head being interposed between the said seat and bolts,
as clearly shown in Fig. 11. In order to attain a nice adjustment of the dies in a
lateral or transverse direction, a wedge-shaped piece is placed at and forms a
backing to the seat h, as shown in Fig. 6, &c.; A nut a secured to the piece a in
conjunction with a screw a, mounted in the cross head, affords means for effecting
such lateral adjustment, the bolts a³ being first loosened for the purpose.
The mechanism for reciprocating the cross-heads is as follows, A driving shaft b
is mounted in the front lower portion of the frame A, the same having a small 62
gear
secured thereto which meshes into a large gear wheel 63, also mounted in the frame.
A pin c is secured to the gear-wheel thereby, in connection with the rod or link c
jointed to the cross-head and pin, producing a crank motion as usual. To the front
cross-head near its lower side is secured a strong guided connection e² having rack
teeth formed in its inner vertical face; this connection is well supported and guided
at its forward end by the extension formed in the frame. A similar toothed
connection is secured to the rear cross-head and mounted in the same horizontal

page_text: plane as the connection c². Intermediate of these racks c², d²; is mounted a vertical
shaft d, having secured at its upper end a strong gear wheel d¹ ärranged to intergear
with both racks, as clearly shown in Figs. 2, and 4. By means of this device it is
obvious that the two cross-heads will be reciprocated in opposite direction's and at
exactly the same relative speed; that is to say, the velocity ratio of the crank é is
imparted to the cross-heads so that both are always traveling and acting in complete
unison.
I will next briefly describe a manner of picking up the blanks and delivering them
to the track or runway T, leading therefrom.
H, indicates a stationary hopper containing loose screw-blanks (See Fig. 9 &c.)
Within the hopper is fitted a narrow double blade m which moves up and down
through the mass of blanks; its upper edge is formed at an angle so that as the
blade arrives at the end of its upward movement any blanks it may have picked up
will readily slide therefrom on to the track T through an opening formed in the
hopper and coinciding with the track. Motion is imparted to the blade or "pick-up",
through the medium of a vertically guided rack m³ secured thereto, which meshes
into a small gear wheel m² loosely mounted on a horizontal shafts. This shaft has
a gear wheel in secured to its inner end which intergears with rack teeth m formed
on the upper face of the rack connection d2: Practically it is found desirable to be
able at times to prevent the pick-up from delivering the blanks; therefore the
gear m² is loosely mounted and is provided with lugs' arranged to interlock with tho
clutch and nut n; the clutch is tongued to the shaft and is adapted to slide end wise,
as common to locking devices of this character:
Referring to Figs. 1, 2, 4 and 5, it will be noticed that a rack-rod s is fitted into
the upper part of the frame, at the rear side; the front portion of said rod is
provided with gear teeth on its under side which engage teeth, 1; cut into the
shafts, See Fig. 4. By this arrangement it is evident that a reduced reciprocating
movement is imparted to the rod s in unison with the cross-head. An elongated
opening is formed in the centre portion of the rear gib-plate a through which a
pin secured to the rear end of the rod s projects. The objects of, this rod, &c., are
to actuate the blank-checking and holding devices about to be described.
Cindicates a plate or tie- uniting the two sides of the frame and being firmly
bolted thereto, its centre being directly over the centre of the space formed by the
separation of the dies when in their extreme position, as shown by broken lines in
Fig. 2. The upper surface of the plate C is cut away or recessed, at f³ to receive
the cam-plate F (See Figs. 21, 19, &c.); a slotted opening f is cut through the
tie-plate to receive said pin u: Two slotted openings f³ are formed in the plate C
along its transverse centre which communicate with a T-shaped groove e² formed.
in the under side of the plate; this groove is for the purpose of retaining the blank-
holding jaws e; gibs e secured to the plate prevent the jaws from dropping out,
although permitting them to travel back and forward, as in opening and closing
when combined with the cam-plate F. The jaws are each provided with a short' pin
or projection et which passes through said openings f. The adjacent vertical faces
or eilges of the jaws are cut out in a semi-circular form k, (Fig. 9) and are
countersunk at the bottom so as to freely receive the' headed blanks t; the jaws are
reduced in thickness at the lower portion, as at e¹, so that they may easily enter the
space formed by the lateral separation of the dies, (See Figs: 9,,10, &c.), the edges'
being concave to more' readily retain the blanks in position.
The plate F is provided with three cam-shaped slots, f;;f cut through it; the
first named slot being adapted to receive the pin u of the rack rods; the other two
which are shorter and are arranged right and left (See Fig. 19, &c. are adapted
to receive the pins et of the jaws e. It is obvious now that by placing the plate F
in the planed out portion of the cap-plate C, and also mounting the jaws in
position beneath the latter plate, that a longitudinal movement of the pin u, extending
through the straight slots u', f, and into the cam' slot f; will cause the plate F to
move back and forward across the machine a distance corresponding to the throw or
the car at the same time, by reason of the engagement of the pin's e¹ with the

page_text: cam-slots the jaws will be made to open and close; the distance traveled being
governed of course by the offset of the cam.
A portion of one of the arms of the cam-plate F extends above the general surface
of the plate and is provided with an additional cam-slot f2; this cam-slot is
substantially of the same length as the lower slot f¹, as clearly shown by the full
lines in Fig. 18.
E, designates a box or frame in which the checking device is mounted; the same
being secured to the centre of the cap-plate C by screws 2. A vertical opening o' is
formed in the rear wall of the box and coinciding with the mouth of the track T.
See Fig. 9 &c. the width of the opening being slightly in excess of the size of the
shank of the screw-blank. The upper portion of the opening is made flaring, as at r,
to freely receive the heads of the blanks. A vertical slot p is forced longitudinally
of the checking-box, the same intersecting the transverse opening o² just described.
indicates a blade or plate fitted to reciprocate in the slot p1; said plate is provided
with a stem on its lower side and engaging the cam-slot 2 of the cam-plate F; the
latter in part being planed into the base of the checking-box, as clearly represented
in Fig's. 8, 10, 13, &c. By means of this construction it will be seen that by moving
the cam-plate back and forward across the machine, the cam-slot 2 will force the
blade p to reciprocate longitudinally of the machine. Now, when the blade stands in
its extreme position toward the left of the box, the column of blanks are held in check,
by reason of the closing of the opening o² thereby. But by moving the blade in the
reverse direction the opening o' will be uncovered and the pressure of the column of
blanks will force then ahead; one of them sliding into the channel p¹ and in line
with the blade p, as shown in Fig's. 8 and 9; the point of the blank rests upon
and is supported by a ledge o³. A spring pin n² mounted in the box E just in
advance of the blank serves to maintain the latter in position until the blade.upon its
return stroke engages it and forces it past the yielding pin n³ and from the support o³,
the blank then drops into the vertical circular opening e', down through a central
hole e formed in the plate C and into the holding-jaws e which at the instant are
separated slightly for the purpose, as shown in Fig. 10. A cover p³ is provided to
close the top of the box E, the same also serving to prevent the blanks from rising.
An extension thereof at the same time maintaining the blanks in position upon the
runway T.
A pin mounted at the rear of the checking-blade, serves when pushed
forward to temporarily keep the column of blanks from passing into the machine.
It will be seen, referring to Figs. 6, 11ª, 13, &c. that two thin strips, h¹, of metal
beveled at their upper edges (as at h²) are arranged to receive the blank between
them immediately upon its being forcibly ejected from the support o³ by the action
of the checking-plate. These metallic strips are secured to the cross-heads contiguous
to the front end of the threading-dies, and serve to support the blank until the
ribs of the dies have fairly commenced to act upon it; at the same time the blank
is maintained in a vertical position by the jaws e which inclose it.
The joint operation of the several devices embodied in my machine is substantially
as follows-
The machine is actuated by a belt leading from a suitably mounted driving pulley
and connected with the mounted pulley b', which by means of the gears 2 and 3,
and the connecting-rod cl jointed to the large gear and front cross-head B imparts a
reciprocating motion to the cross-head; the latter now in traveling, by reason of the
connected rack 2 and gear d', gives a similar (but reversed) movement to the rear
cross-head through the medium of the gear and the inter-gearing rack d³ secured
to the rear cross head, all as clearly shown in Fig. 2.
Now, in order to thread the blank t, we will assume that it is retained in position
by and between the jaws e (See Figs. 13 and 15) and resting upon the beveled edges
of the strips (Fig. 11") and that the cross-heads are at the extreme or normal
position shown in Figs. 1, 2 and 6; next, by revolving the main gear in the arrow
direction the front cross-head with its die will be forced ahead, which movement
through the medium of the racks and gear d¹ forces the rear cross-head with its die
in the opposite direction. (The relation of the cap and cam-plates to each other

page_text: being as represented in Fig. 15.) This movement of the cross-head &c. will cause the
cam-plate F to slide rearwardly, through the medium of the rods and its mounted
pin which works in the cam slot f, thereby, in conjunction with the two cam-slots /¹
and pins et, separating the jaws e; at the same time the cam f2 acting upon the
checking-plate p, will be forced rearwardly to uncover the opening o². See Fig. 8
and dotted line position Fig. 18. The form and travel of the several cams, &c., being
so arranged and timed that the holding-jaws begin to open immediately after the ribs
of the thread-forming dies D have seized upon the blank. The continued travel of
the dies impress a screw-thread into the blank. An example of dies adapted for this
purpose is shown and claimed in United States Patent No. 370,354, granted to me
September 20th, 1887. As the dies pass each other at the extreme of their travel
corresponding to the forward dead centre of the crank-pin e, the threaded blanks will
drop from them into a space beneath. Upon the rearward stroke and immediately
preceding its termination the next blank to be acted upon will be forced from the
channel o² and past the spring or check pin n² into the jaws e by the action of the
cam and the checking-plate p. Fig. 10 represents a blank having been thus
deposited between the jaws e before the dies have quite reached the end of the rear-
ward stroke. At the commencement of the next forward stroke the blank will be
retained by the closed jaws and also supported by the strip h', as clearly shown in
Fig. 13. The dies now in again travelling ahead seize the new blank between them
and roll or impress a screw-thread upon it, as just described. It is of course under-
stood that during the reciprocation of the cross-head the blanks are automatically
fed from the hopper and along the track T to the checking-device by the vertically
traveling pick-up blade.
By means of my arrangement the method of actuating the threading-dies is greatly
simplified. An important advantage resulting therefrom being that the movement
of the dies is always coincident with each other.
It will be seen that provision is made whereby all the working parts of the
machine are readily accessible and also adjustable.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In a machine for forming screw-threads upon metal blanks, the combination of
two mounted threading-dies arranged to reciprocate past each other, and mechanism
for effecting such movement, consisting of a toothed rod secured to cach die or
cross-head, a loosely mounted gear-wheel meshing into both toothed rods and a con-
necting rod jointed to one of the cross-heads and to a suitably mounted crank-pin,
whereby the crank in revolving imparts a reciprocating motion to the dies in
opposite directions, substantially as described.
2. In a machine of the class described, and in combination, a cross-head having a
threading-die mounted therein, a rack, as c², secured thereto, a link jointed to the
cross-head and connected with a suitably actuated crank, a cross-head carrying a
fellow threading-die and having a reversely arranged rack, as d, connected therewith,
and a loosely, mounted gear wheel, as d, meshing into both racks, constructed and
arranged substantially as described and for the purpose specified.
3. The combination of two, oppositely mounted and reversely arranged cross heads,
each having a toothed rod or rack secured thereto, an idler gear-wheel intergearing
with both racks, and a crank-driven rod jointed to one of the cross-heads, whereby a
continuous rotary motion is converted into a reciprocating movement to one cross-head
which latter imparts a like movement to the other cross-head, but in a reverse
direction, substantially as set forth.
4. In a machine for forming screw-threads upon blanks, the combination with two
supporting threading-dies mounted to travel in opposite directions, and a pick-up
blade or finger mounted to pick-up and guide the blanks to a runway, of a checking-
device having a pusher, as p, for forcing the blanks singly into slightly separated
recessed jaws beneath, and having means for closing the jaws prior to the engagement

page_text: of the threading dies with the blank, although when closed permitting a free axial move-
ment of the blank, and means for separating the jaws in advance of the completion
of the screw-thread so that the threaded blank may readily drop from the dies after
they have completed their work.
5. The combination of two parallel cross-heads carrying threading dies reversely
arranged, and connected with each other by racks and a gear-wheel inter-meshing
them with and actuated by one of the cross-heads, and intermittingly operated pushing-
plate arranged to uncover the lower end of the track to permit a blank to enter the
feed box and then to force it therefrom, and intermittingly actuated jaws for receiving
the blank and releasing it after being acted upon by the dies.
6. In a machine for screw-threading screw blanks, the combination of oppositely
mounted and reversely traveling dies having each a blank_supporting strip, as h', at
its front end, a stationary feed-box or checking device, as E, communicating with the
track leading from the hopper, a pusher-plate p mounted to travel in the checking-
box, jaws mounted below the checking-box for receiving and releasing the blanks, and
a cam-plate, as F, connected so as to reciprocate across the machine, and cause the
pusher plate and jaws to travel in unison substantially as shown and described and
for the purpose hereinbefore set forth.
7. In a screw-threading machine, the combination with the screw-threading die, a
die holder, and a cross head having said die and holder mounted therein, of an
adjustably mounted backing-piece or thrust-block interposed between the holder and
cross-head constructed and arranged whereby a lateral adjustment of the die is
effected, substantially as shown and set forth.
CHARLES DAKE ROGERS.