IMPROVEMENTS IN SUBSTITUTES FOR SCREW BOLTS AND NUTS, AND IN THE METHOD OF Manufacturing THE SAME." PROVISIONAL SPECIFICATION
Year: 1880

page_text: LETTERS PATENT to Nathan Thompson, of Brooklyn, in the County of Kings,
and State of New York, in the United States of America, but at present of
23, Southampton Buildings, in the County of Middlesex, for an Invention of
"IMPROVEMENTS IN SUBSTITUTES FOR SCREW BOLTS AND NUTS, AND IN THE
METHOD OF Manufacturing THE SAME."
PROVISIONAL SPECIFICATION left by the said Nathan Thompson at the
Office of the Commissioners of Patents on the 24th April 1880.
NATHAN THOMPSON, of Brooklyn, in the County of Kings, and State of New
York, in the United States of America, but at present of 23, Southampton
Buildings, in the County of Middlesex. "IMPROVEMENTS IN SUBSTITUTES FOR
SCREW BOLTS AND NUTS, AND IN THE METHOD OF MANUFACTURING THE
SAME."
In the Specification of Letters Patent granted to me, dated January 23, 1879,
No. 290, I described a slotted bolt and a curved rotative wedge to be used as a
substitute for ordinary screw bolts and nuts. In such description of fastenings
constructed as therein described the curved rotative wedge when subjected to
continued vibration was liable to work loose. I overcome this difficulty by forming
one or more shallow nicks or recesses across the outer side of the wedge near the
head thereof, whereby when such wedge is forced home the nicks or recesses will
catch on to the edges of the spring washer on the sides of the slot through which
the bolt passes, by which means the wedge is prevented from working loose'
however much vibration may be imparted to it.
In order to lighten the slotted bolt used in combination with the curved rotative
wedge without impairing its strength I connect the two sides of the bolt together
from the head to the slotted opening by a comparatively thin web instead of
carrying the full width of metal right across; this web is sufficiently strong to
prevent the opening out of the sides of the bolt whilst the sectional area of such
sides is equal to that of the metal on both sides of the slotted opening.
According to my present Invention I manufacture the above mentioned slotted
bolt by means of a series of swages acting to produce the desired shape, and after

page_text: the action of the last swage I trim off the fins left around the bolt and clear out any
metal left in the slotted opening; or I pass a bar of suitable size through a series of
suitably shaped grooves in a rolling mill, and after the last pass I separate the bolt
lengths, and then trim off the fins therefrom and clear out the slotted opening. I
also place the bolt in a suitable die, and by pressure applied to the bolt head force
the underside thereof on to the upper face of the die to flatten the same and render
it fit for use.
I form the curved rotative wedge by stamping the same to the required shape
out of plate metal of suitable thickness, and then trimming off the burrs, after
which, for some purposes, I harden the same; or in order to provent waste of the
plate metal as far as possible I cut or stamp a number of straight wedges, and then
by suitable tools force the same into the required shape, after which they may be
hardened.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Nathan Thompson in the Great Seal Patent Office on the 23rd
October 1880.
NATHAN THOMPSON, of Brooklyn, in the County of Kings, and State of New
York, in the United States of America, but at present of 23, Southampton
Buildings, in the County of Middlesex. "IMPROVEMENTS IN SUBSTITUTES FOR
SCREW BOLTS AND NUTS, AND IN THE METHOD OF MANUFACTURING THE
SAME."
In the Specification of Letters Patent granted to me, dated January 23rd, 1879,
No. 290, I described a slotted bolt and a curved rotative wedge to be used as a
substitute for ordinary screw bolts and nuts. In such description of fastenings
constructed as therein described, the curved rotative wedge when subjected to
continued vibration was liable to work loose. I overcome this difficulty by forming
one or more shallow nicks or recesses across the outer side of the wedge near the
head thereof, whereby when such wedge is forced home the nicks or recesses will
catch on to the edges of the spring washer on the sides of the slot through which the
bolt passes, by which means the wedge is prevented from working loose however
much vibration may be imparted to it.
In order to lighten the slotted bolt used in combination with the curved rotative
wedge without impairing its strength I connect the two sides of the bolt together
between the head and the slotted opening by a comparatively thin web instead of
carrying the full width of metal right across; this web is sufficiently strong to
prevent the opening out of the sides of the bolt whilst the sectional area of such
sides is equal to that of the metal on the sides of the slotted opening.
According to my present Invention I manufacture the above mentioned slotted
bolt by means of a series of swages acting to produce the desired shape, and after
the action of the last swage I trim off the fins left around the bolt and clear out any

page_text: Figure 1 is a side view, and Figure 2 an edge view of one of my improved
curved rotative wedges; Figures 3 and 4 are two different side views; and
Figure 5 is a cross section of one of my improved slotted bolts; Figuro 6 is a
plan; and Figure 7 is a cross section of a spring washer such as I prefer to
employ in combination with my improved curved wedge; Figure 8 is a cross
section representing my improved wedge and bolt in use; Figures 9 and 10 are
two different side views; and Figure Il is a cross section of a bar rolled to a
suitable form to be employed in the construction of my improved slotted bolt;
Figures 12 and 13 are two different side views of a bolt length or blank cut off
from such bar; and Figures 14 and 15 are two different side views of such bolt
length after certain operations have been effected upon it, but before the head
thereof has been formed.
In all the Figures like parts are marked with similar letters of reference.
a represents my improved curved rotative wedge, its general construction is similar
to that shown and described in the Specification of my Patent horeinbefore referred
to; but in order to prevent the possibility of the said curved wedge working
loose under great vibration I, according to my present Invention, form on the outer
surface a of the curved wedge one, or preferably two, notches or recesses a².
The slotted bolt b, according to my present Invention, is formed as shown at
Figures 3, 4, and 5 in order to lighten it without impairing its strength; this I
effect by connecting the two sides 63 of the bolt together between the head
thereof, and the slotted opening by a comparatively thin web 63 instead of
carrying the full width of metal right across; this web 63 is sufficiently strong to
prevent the opening out of the sides 6 of the bolt whilst the sectional area of such
sides is equal to that of the metal on the sides of the slotted opening b².
The improved rotative curved wedge and slotted bolt may be used in combina-
tion with ordinary flat washers or in combination with spring washers c hollowed
on their under surface, and preferably formed with small ribs or projections c¹ on
two opposite sides of the hole or slot therein, as shewn at Figures 6 and 7; the two
ribs or projections c¹ enter the notches or recesses a² of the curved wedge, and
thereby prevent the possibility of the latter running back, even when subjected to
great vibration.
Instead of casting or forging slotted bolts by hand I, according to my present
Invention, manufacture the above described slotted bolt by means of a series of
swages acting to produce the desired shape, and after the action of the last swage I
trim off any fins which may be formed on the exterior of the bolt, and clear out
any metal left in the slotted opening, or I pass a bar of suitable size through one
or more suitably shaped grooves of a rolling mill to produce a bar of the shape and

page_text: sections represented at Figures 9, 10, 11. I then separate the said bar at the lines
x, x, into bolt lengths or blanks, one of which is shown at Figures 12 and 13, after
which, by the aid of suitable dies, I punch or cut out the slotted opening b¹ round
the cross bar b, at the end of the slotted opening 6, and by the aid of suitable
dies or swages upset the part comprised between the lines x, x, and y, y, to form
the head of the bolt.
By the preliminary formation of the recesses 63 in the bolt blanks, as shown, the
operation of punching or cutting out the slotted opening b¹ is greatly facilitated,
and distortion and straining of the metal by such punching are prevented. Any
fins are cleared off, and the bolt is ready for use.
Instead of casting the curved rotative wedges or forging them as heretofore I,
according to my present Invention, stamp the samo to the required shape out of
plate metal of suitable thickness, after which I trim off any burrs which may have
been formed, and for some purposes harden the same; or in order to prevent waste
of the plate metal as far as possible I cut or stamp straight wedges, and then by
suitable tools force the same into the required shapo, after which they may bo
hardened.
Having thus described the nature of my said Invention, and the mode in which
I carry the same into effect, I would have it understood that what I claim is--
First. Forming the curved wedge a with one or more notches or recesses a³, as
and for the purpose stated.
Second. Forming the slotted bolt b with a thin web b³ connecting the two
opposite sides of the bolt, as and for the purpose stated.
Third. Manufacturing the curved rotative wedge a by stamping or cutting the
same out of plate inetal to the required shape, or by first forming straight wedges
and then shaping and finishing the same, as and for the purpose stated.
Fourth. Manufacturing the slotted bolt by the aid of a series of swages or partly
by rolling and partly by stamping and swaging, as and for the purposes stated.
In witness whereof, I, the said Nathan Thompson, have hereunto set my
hand and seal, this Twenty second day of October, in the year of our
Lord One thousand eight hundred and eighty.
NATELAN THOMPSON