Improvements in the Manufacture of Screws and in Apparatus therefor.
Year: 1892

page_text: Date of Application, 15th Mar., 1892-Accepted, 16th Apr., 1892
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Screws and in Apparatus
therefor.
I, LEONARD DOIG, of 47 Upper Thames Street in the City of London,
Manager of The Russell and Erwiu Manufacturing Company, 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 statement :-
My invention relates to improvements in methods of and means for rolling screws,
and the product thereof, and the objects of my improvement are to facilitate the
process of rolling, to produce an improved product, and to improve the means
employed in said process.
In the accompanying drawings,
Figure 1 is a plan view of my dies and die holder with the cap removed.
Figure 2 is a side elevation of the same with the cap in place."
Figure 3 is a vertical section of the same on line, of Figure 1.
Figure 4 is a like view of parts of the same with different adjusting devices for
the shank rolling die.
Figure 5 is an enlarged face view of a portion of one of the shank-rolling dies
with one form of working face.
Figure 6 is a side view of a screw as rolled in the dies illustrated in Figure 2.
Figure 7 is a side view of a screw as rolled in like dies with the shank rolling
and thread rolling dies separated by a blank space, and
Figure 8 is a side view of a screw. having its shank portion rolled with the die
Figure 5.
The dies and die holders as shown are of the class in which a pair of straight
dies are set face to face and made to reciprocate in front of one another and any of
the ordinary machines for that purpose may be employed. A suitable machine for
this work is shown and described in my United States Patent No. 419,777, dated
January 21, 1890. My method or process may however be practised by means of
cylindrical or curved dies.
A designates a die holder on which I set the die block B. In the face of this
die block I set the thread rolling dies 9, and I secure the same in place by means
of a cap C and bolts 11, the latter passing through holes in said cap and die block.
Said die block is also provided with a sub die block 12 having holes, through which
said bolts 11 pass. These holes in the die block and sub die block are somewhat
larger than the bolts to permit of adjustment. Adjusting screws 13 are screwed
into the back of the die holder with their heads resting on the back of the die block
as shown in Figures 1 and 3. The sub die block 12 lies in a rebate on the top of
the die block B and between it and the back shoulder 14 of said rebate at each end
there is a wedge 15. Secured to each end of the die block there is an end piece 16
through which adjusting screws 17 extend with their grooved ends 18 resting in
shouldered recesses in said wedges as clearly shown in Figure 1. The thread rolling
dies 9 not only thread the body of the screw but they have the usual raised or
more prominent portion 19 near their bottom edge for threading the pointed portion
of the screw. Any ordinary dies for rolling the threads on pointed wood screws
may be employed. An example of a suitable die for so doing is found in my
United States Patent No. 425,035, dated April 8, 1890. The thread-rolling die
will be placed in front of the solid portion of the die block while the sub die block
will be back of the shank rolling die.
In use a pair of each of the dies will be employed although I have shown_only
one of them, and they will be set face to face the proper distance apart to roll the
screw between them. By loosening the bolts 11 and turning the adjusting screws 13

page_text: the complete die block, dies and all, may be adjusted so that the thread rolling dies
will be the proper distance apart, all substantially as in machines now in use so far
as adjusting the complete die block is concerned. If it should be found that the
shank rolling dies are not properly adjusted they may be separately adjusted
without disturbing the adjustment of the thread rolling dies by turning the
adjusting screws 17 to move the wedges 15 to set and hold the sub die block
farther out or in to properly support the shank rolling dies in position. While
my dies with the separate adjustment are especially adapted for use in rolling
pointed wood screws it is evident that this feature of my improvement is applicable
to dies for rolling tyre bolts or pins such as are described in my United States
Patent No. 446,739 dated February 17, 1891.
In Figure 4 I have shown the sub die block as made adjustable by set screws 20,
one at each end, extending through the back shoulder of the die block, and
bearing upon the rear edge of the sub die block 12 as a substitute for the adjusting
screws 15 first described.
The working face of the shank rolling die in Figure 2 is shown as consisting of
slightly oblique ribs and grooves to produce spiral elevations and depressions 23 as
shown on the shank of the screws in Figures 6 and 7. The working face of the
die is shown in Figure 5 as consisting of intersecting grooves and diamond shaped
elevations to produce a reticulated configuration of shank as shown on the screw
in Figure 8.
Having shown these two designs in the working face of the shank rolling dies,
other designs may be readily devised for giving the desired form to the raised
portion of the shank.
I have also shown the raised portion of the shank as extending from the screw
lead to the thread, and the shank rolling dics as set close to the thread rolling dies,
but it is evident that these dies may if desired be separated more or less by
placing a strip of metal between them, or by forming a blank space on the face of
the die as shown and described in my aforesaid United States Patent No. 446,739
thereby producing the screw Figure 7. It is also evident that a longer screw
might be rolled in the dies herein shown, with a blank space on the shank between
the head and raised portion of the shank. In using my dies the raised portion of
the shank and the thread on the body and point of the screw
are rolled
simultaneously. In rolling a thread on a wood screw the thread is so coarse that
the screw is very liable to be bent where the thread runs out at the shank. By
simultaneously rolling the raised portion of the shank and the thread, especially if
the raised portion of the shank has spiral or reticulated elevations and depressions,
this bending at the junction of the shank and thread is practically overcome.
In
rolling gimlet pointed wood screws there is a severe strain on the stock having a
tendency to force the work endwise away from the portion 19 of the dies that
thread the point. By simultaneously rolling the point, and shank, the stock is
much better held up to the work of threading the point with any design of shank
rolling dies, but in the reticulated design, as in Figures 5 and 8 the working face
of the die forms a positive lock against such end wise slipping of the blank. The
advantage of simultaneously rolling the shank and the point of the screw may be
reaped even if the thread on the body of the surew is not rolled at the same time.
For example suppose a pointed screw blank had the thread rolled on its body in
dies that had no point threading portion, thereby leaving the point plain while the
body was threaded. A blank or partially finished screw of this kind may be
placed in the dies as herein shown and the thread on its point rolled simultaneously
with rolling the shauk.
In rolling a wood screw there is a tendency of the blank to slip so that it does
not rotate in unison with the movement of the thread rolling dies and to prevent
this slipping it has been found necessary to transversely notch or roughen a
considerable portion of the dies.
This is objectionable because the thread produced is somewhat ragged and rough
instead of being smooth and solid. By simultaneously rolling the shank and thread

page_text: the dies which roll the raised portion of the shank act in connection with the blank
like a pair of racks and a pinion and insure the proper rotation of the blank so that
the dies need not be roughened and a smooth and solid thread can be rolled. So
also the shank rolling dies will cause the screw to rotate properly therein when the-
thread on the point only is rolled simultaneously with the shank.
Having shown two different adjusting devices for separately adjusting the shank
rolling dies and known adjusting devices for adjusting the complete die block, it is
evident that the particular adjusting devices shown are not essential to the general
combination of said dies and adjusting devices.
The die blocks and sub dic-blocks as separate pieces from the thread rolling and
shank rolling dies, are for convenience in making but inasmuch as the die block
and thread rolling die move together when adjusted, and the sub die-block aud
shank rolling dies also move together when adjusted, it is evident that making each
die block and its die in one piece instead of two separate pieces would be a clear
equivalent, so far as the combination of adjusting devices is concerned.
In the screws shown in Figures 6, 7, and 8, 21 designates the ginlet point,.
22 the threaded body, 23 the shank and 24 the ordinary bevelled head for which
the ordinary half round head may be substituted if desired. The screw head is
provided with a nick or slot 25 to adapt it for engagement by a driver for turning
the screw axially to force it into the wood. A portion of the whole of the shank 23
is uneven and covered with elevations and depressions as formed by the shank
rolling dies; said elevations and depressions being preferably in the form of spiral
ribs as shown in Figures 6 and 7, although as suggested by the different con-
figuration of the shank rolling dies they may have a reticulated or other form if
desired as shown in Figure 8. The greatest diameter of the shank should be
approximately equal to that of the threaded body.
These screws with any desired design of elevations and depressions on the shank
may be rolled with said elevations and depressions extending to the threaded body
as in Figure 6, or by leaving a blank space 27 under the head as shewn in Figure 8..
I prefer to have the blank space 27 of the same diameter as the rest of the shauk
and this may be done by forming it in the heading dies simultaneously with forming
the head, the remainder of the blank being then left of normal size and subsequently
enlarged by rolling.
The advantages of this form of screw in the process of rolling have been pointed
out in connection with the description of the rolling dies. In turning the screw
into the wood the threaded body draws it in as in ordinary screws and the
elevations and depressions on the shank ream out the hole in the wood to the size
of the ribbed shank, whereby said shank necessarily substantially fits and fills the
hole. It may also be observed that the material cut from the wood in thus reaming.
out the hole firmly fills the depressions in the shank so as to form practically a solid
cylinder.
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 :-
First. In dies for rolling screws, the combination of the thread rolling dies, and
adjusting devices for separately adjusting the said shank rolling dies, substantially
as described and for the purpose specified.
Second. In dies for rolling screws the combination of a die holder, a thread
rolling die, the shank rolling die, devices for adjusting the thread rolling die on the
die holder, and devices for separately adjusting said shank rolling die, substantially
as described and for the purpose specified.
Third. The combination of dies having a raised portion for rolling a thread on
the point of the screw and dies for rolling the shank, the same acting together on
the shank and point of the screw, substantially as described and for the purpose
specified.
Fourth. The method of rolling gimlet pointed wood screws which consists of

page_text: simultaneously rolling the thread on the point and elevations and depressions on
the shank whereby the action of the dies in rolling said shank insures the rotation
of the blank within the dies and also tends to hold the blank up to the work of
threading the point-as described.
Fifth. A screw having a head adapted to be engaged by a driver for turning 5
said screw axially and a series of elevations and depressions on its shank raised up
from the body thereof by rolling or swaging substantially as described and for the
purpose specified.
Sixth. A wood screw having a threaded point and body and a shank formed
with a surface consisting of elevations and depressions raised from its body by
rolling or swaging substantially as described and for the purpose specified.
Seventh. A wood screw having a rolled thread on its point and body, and a
shank having a series of elevations and depressions, raised from its body by rolling
or swaging substantially as described and for the purpose specified.
Eighth. A wood screw having a rolled thread on its body and point and a shank
having a series of rolled elevations and depressions in the form of ribs extending
spirally along said shank substantially as described and for the purpose specified..
Date : 15th day of March 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.