IMPROVEMENTS IN WOOD SCREWS AND IN THE MANUFACTURE THEREof.
Year: 1877

page_text: 'LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Patent Agents, of 67, Ştrand, in the City of Westminster, Civil
Engineer, for the Invention of "IMPROVEMENTS IN WOOD SCREWS AND IN
THE MANUFACTURE THEREof.' A communication from abroad by Reinhold
Boeklen, of the City of New York, United States of America, Engineer.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at
the Office of the Commissioners of Patents on the 18th August 1877.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Patent Agents,
of 67, Strand, in the City of Westminster, Civil Engineer. "IMPROVEMENTS IN
WOOD SCREWS AND IN THE MANUFACTURE THEREOF." A communication from
abroad by Reinhold-Boeklen, of the City of New York, United States of America,
Engineer.
This Invention relates, firstly, to an improved wood screw furnislied with a
centre-bit point, an auger-bit cutting or entering edge, and a screw thread upon its
shank, the outer periphery of which is raised to a larger diameter than that of the
unthreaded shank of the same; and, secondly, to the mode of making the said
improved screw by cold rolling the thread upon it and by milling the point
to it.
The improvements may be performed by taking metal wire of the desired guage
and forming it into blanks by stamping, rolling, or otherwise, and by means of dies
furnished. with threaded faces fitted to convenient rolling machinery rolling threads
on said blanks.
For the purpose of feeding and guiding the blanks during the operation, one or
more guide tubes may be used; the said rolling machinery is supplied with cams
and levers for passing or feeding the blanks through the guides, and tumblers with
plungers proportioned to the length of the screw required are used for regulating
the feed.
The milling of the point may be performed by any convenient milling annaratus

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Herbert John Haddan in the Great Seal Patent Office on the 12th
February 1878.
26
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Patent Agents,
of 67, Strand, in the City of Westminster, Civil Engineer. IMPROVEMENTS IN
WOOD SCREWS AND IN THE MANUFACTURE THEREOF.' A communication from
abroad by Reinhold Boeklen, of the City of New York, United States of America,
Engineer.
This Invention relates, firstly, to an improved wood screw, furnished with a
centre-bit point, an auger-bit cutting or entering edge, and a screw thread upon its
shank, the outer periphery of which is raised to a larger diameter than that of the
unthreaded shank of the same; and, secondly, to the mode of making the said
improved screw, viz., by cold rolling its thread upon it and by milling its point to
it. By means of said centre-bit point the screw in placing will enter the wood
accurately, and by means of its auger-bit cutting edge will cut its way and pass
readily with little power into the wood, and its shank following with equal diameter
is not apt to split the wood by means of its thread being larger than the unthreaded
shank or throat; the drilling of a hole for the threaded and unthreaded shank is
dispensed with; the throat is not apt to split the wood, nor does it interfere and
stop the screw from drawing up tight, so that two pieces of wood are readily secured
firmly with the screw without drilling, a hole in the wood.
The screw is made by rolling its screw threads cold upon it, consequently its shank
is made hard and stiff; it is thereby less liable to bend and can be made at smaller
expense, and with a large space for solid wood between its screw threads to provide
for superior holding power in soft wood.
In the Drawings annexed Figure 1 represents a side elevation of the improved
wood screw,
shown on an enlarged scale; Fig. 2 is an end view of the pointed end
of the same.
Fig. 3 represents a top view of the machine for rolling the thread upon the screw;
Fig. 4 is a longitudinal section of the same through the central line; Fig. 5 is a face
view of the same across the dies, the front bearings shown removed.
Fig. 6 is a detached rear view of the dies, showing the guide for holding the
screw between the dies, and its mechanism for operating the same.
Fig. 7 is a detached view of the cam and levers for causing the feed motion and
drop of the guide.
Fig. 8 is a detached front view of the tumbler and motion of the same.
Fig. 9 represents a longitudinal section of a modification of the machine for rolling
the screw thread upon the screw.
Fig. 10 is a front view of the same, the front bearing shown removed,
Fig. 11 is a top view of the milling tools for milling the point on the screw.
A, Fig. 1, represents the head; B, the unthreaded shank or throat; C, the threaded
shank; D, the point; and E the commencing portion or auger cutting edge from
the point D to the threaded shank C of the screw. The head A is of the ordinary
shape and is made with the ordinary process of heading. The bottom or inner
periphery of the threaded shank C is depressed or made smaller in diameter than
that of the shank B, while the outer periphery of the screw thread of the threaded
shank C is raised to a greater diameter than that of the shank B, shown in dotted
lines in Fig. 1, the object of which is to cause the shank to enter easily and still
tightly fit the wood without splitting the same, and at the same time to avoid the
necessity of boring a hole in the wood for it.
The wood screw with a shank and threaded portion with relative diameters, as
above described, is threaded by rolling, as herein-after shown, by a process which is
less expensive than that used ordinarily of cutting the threads of the wood" screw;
the shank by rolling becomes hardened, is therefore made stiffer, harder, and stronger,
.consequently less liable to break and bend than that of the cut screw.

page_text: The screw threads are formed, without adding to expense, with a large space for
wood between them, and consequently the holding power of the screw, specially for
soft wood, is a great deal improved. The point D is inade taper and similar to the
point of a centre-bit; it enters the wood easily; and by it the screw is readily placed
accurately and is guided properly in passing into the wood, and does not follow the
softer portions of the wood: From the base of the centre-bit point. D the threaded
shank C commences with a starting portion E, which circumscribes one, or less than
one, turn of the screw; it commences with a sharp edge and minimum radius at the
base of the point; its radius increases gradually until meeting the periphery of the
screw thread of the shank C, and is made sharp along its edge like that of the
auger-bit.
"
To enter the wood easily and cut its way, the portion C is made of equal diameter
to follow the portion E, consequently the portion or shank C is not apt to split the
wood.
The machine for rolling the screw thread upon the screw has a bed A upon which
three vertical bearing frames B are erected, as shown in Figs. 3, 4, and 5. In said
frames are carried two opposite horizontal shafts C, C, and upon the portion of said
shafts, between the two forward frames, are solidly mounted the threaded dies D, D,
between which the screw is rolled and threaded. Each of said frames is furnished
with bearing or journal boxes for the said shafts. Between the two rear frames the
said shafts have upon them strong gear wheels E, E, which are both engaged by one
large pinion gear F upon a third horizontal shaft G below the shaft C, Č. And said
shaft G is the driving shaft of the machine, and is furnished on its rear end with a
fast and loose pulley H and a fly wheel I, and it has its bearings in the. two rear
frames. Along one side of the machine is secured a side frame J, which is vertically
erected upon the bed A and combines the three frames B..
The bearings of the shaft C near the side frame J are all made permanent, but
the bearings of the shaft C opposite are made adjustable with the wedges K and
set screws L, through the caps M, so that the latter shaft C, with its bearings and its
die can be set nearer or farther from the shaft C opposite, for the purpose to roll
screws of different diameters: The rear frame is provided with a bridge across, in
which the back centres or set screws N are employed to set up the said shafts C
against wear, and also to adjust the dies longitudinally with their screw threads.
The dies D, D, are circular, with exception of a short part d, d, of their periphery,
which is cut away to allow the screw to: discharge after being threaded, and to
admit, the blank for the screw to enter for being threaded. They are made of solid
tempered steel; the periphery has the screw thread upon it, which is of the same
pitch on both dies, but is arranged in reverse direction, and both have a pitch
determined by the unwinding of the periphery of the screw upon the periphery of
the die, and the amount of stretch of the screw during its compression. The threads
upon the dies are relieved, as shown, to engage the screw gradually. The screw
enters between the dies in the plane through their axis...
To hold the same in proper position for threading is employed a concentric guide
plate O, which swings on the shaft C, is forced off by the lever arm P, upon the
shaft and the connecting link R attached to said guide, as shown in Fig. 6. By
imeans of the spring S said guide is brought back in position to rest the screw for
threading. To stop the blank longitudinally at the proper position is employed a
set screw T, which is secured in the central part of the central frame B.
•
To forward the blanks for screws to the dies is employed a vertical feed pipe U, into
which they are either fed by the automatic fork feed (well known) from an ordinary™
hopper, or they may be fed from the nicking machine direct. From tlie tube U they
are taken one by one into the vibrating tumbler V, which has a central opening Vi,
into which they are received at every turn of the machine when said opening is
turned to a vertical direction. Said tumbler works in the box V", which prevents
the blank dropping through; at the proper period of motion the opening Vis
turned with the blank in it to a horizontal position, and the blank is, by means of
horizontal plunger W, working in the guide W, forwarded over the guide. plate

page_text: O, between the dies. A small roller x is employed on the upper periphery of the
tumbler to apply its weight upon the head of the blank while passing under it
to make sure of the blank being pressed below the periphery of the tumbler.
To move said plunger and tumbler, and also to cause motion to the shaft Q and
the guide O connected with it, is employed a cam X upon the shaft C, shown
clearly in Fig. 7. Upon the shaft Q is an arm Y bearing with a friction roller
against said cam; on said shaft Q is attached, forward of the front frame, an àrm Y¹,
which is connected with a right angular lever Z, and the latter is connected with
the plunger lever Z" by means of a rod Z¹¹¹.
The lever Z has two arms, one to connect with the plunger lever, the other with
the arm Y¹, by means of a rod Y", which has a ball joint to allow the proper side
motion. With the plunger lever Z is also connected, by means of the rod Y, the
tumbler V; and the plunger lever and plunger are connected by the link W",
shown in Fig. 8. The plunger lever Z¹¹ moves the tumbler in the direction for
receiving the blank, a spring * is employed to move it back in the position for
discharge of the same.
After the blank is fed between the dies the screw threads are first started to
impress upon the shank, near the head, and gradually more and more spreading
towards the point of the screw, and the periphery of the dies being somewhat
excentric, provides for a gradual impression; also in depth of the thread by
the determination of one revolution and a little less; the guide O is allowed
to drop, and 'the concave part of the die allows the discharge of the screw.
•
The screw is hereafter fed in the milling machine to have its point milled;
said milling machine consists of a hollow rotating spindle with a clamp b, shown in
Fig. 11; said clamp is properly opened and closed by automatic mechanism usually
employed in screw-threading machines. The screw is then forwarded with the
clamp to enter with its point through the guide c, which has the proper screw
threads to engage those of the screw; in coming through said guide c, its point is
engaged by the milling wheels d', d¹, which cut its end. One of said wheels is set
ahead and cuts into the groove to form the cutting edge of the screw, while the
other opposite mills the point. The machine thereafter retreats from the die c, and
the clamp opens and receives from the rear another blank, which discharges the
finished pointed screw.
The machine for threading may be modified; instead of having two rotating dies
rotating in like direction to roll the screw between, there may be employed one
rotating die 1, in combination with a stationary die 2, shown in Figs. 9 and 10;
in such case the rotating die is firmly secured upon the shaft 3, which has a large
gear 4, and has a bearing 5 in the frame for its rear portion, and a bearing 6 for its
forward portion. By means of a counter shaft 7 on the side of the frame 8,
with driving pulleys, and a pinion to engage said gear 4, the die is rotated.
The stationary die is located in a box furnished with set screws 9, to adjust it
properly for the rotating die..
Both dies are made with the proper screw threads to make the desired impressed
screw thread upon the screw, which enters at the lower end of the stationary die,
and is guided for proper entrance between them by means of a swinging guide O,
which is moved by the cam X, as above described, upon the shaft of the die; at the
place of entrance of the screw between the dies is employed the tumbler V with
the appendages as above described, almost identical, with exception of the moving
parts for the plunger lever which, in this case, is connected with a vertical lever 10
pivoted to the front bearing and engaging the cam 11, mounted on the outer end of
the shaft of the die. A machine of this construction is less expensive than that
before described but requires a greater number of dies and more expensive dies than
that above described.
What I claim as my Invention is,―
1. The improved wood screw, herein described and shown, with a threaded shank,
the inner periphery reduced, and the outer of the thread raised from the shank B,
or diameter of the wire it is made from and with a
nanter hit moint and

page_text: bit cutting edge for starting, substantially as and for the purpose herein shown and
described.
2. The combination of the die or dies with threaded faces with the automatic feed,
substantially as and for the purpose herein shown and described.
3. The combination of the tumbler feed with the feed tube and plunger, sub-
stantially as and for the purpose herein set forth.
4. The combination of the die or dies with the threading surfaces, and the
swinging guide O, substantially as and for the purpose herein mentioned.
5. The combination of the screw clamp b, the guide c, and milling wheels d³, d³,
to shape the point of the screw, substantially as herein shown and described.
6. The combination of the dies D, D, the guide O, the feed tube U, the tumbler V,
and plunger Z¹¹, substantially as and for the purpose herein stated.
In witness whereof, I, the said Herbert John Haddan, have hereunto set my
hand and seal, this Seventh day of February, in the year of our Lord
1878.
H. J. HADDAN. (L.S.)