IMPROVEMENTS IN BOLTS AND NUTS AND IN THE METHOD OF FIXING THE SAME "
Year: 1882

page_text: LETTERS PATENT to Robert Howarth of Wolverhampton in the County of
Stafford for an Invention of "IMPROVEMENTS IN BOLTS AND NUTS AND IN
THE METHOD OF FIXING THE SAME
"
PROVISIONAL SPECIFICATION left by the said Robert Howarth at the
"IMPROVE-
37
Office of the Commissioners of Patents on the 14th November 1882.
ROBERT HOWARTH of Wolverhampton in the County of Stafford
MENTS IN BOLTS AND NUTS AND IN THE METHOD OF FIXING THE SAME."
This invention relates specially to bolts and nuts employed for securing the
fished joints of railway rails, and has for its object the complete prevention of the
bolts from working loose under the jarring action of the traffic. The invention is
applicable however to bolts used in other positions rendering them subject to
vibration
A bolt constructed according to this invention has no enlarged head, but a
square or other shaped part to receive a spanner is formed down at one end over
which a nut may readily pass. The bolt is provided with a nut at each end and is
screwed differentially, that is to say, it has a thread run on from one end of a
coarser pitch than the thread run on from the other end, for instance one thread
may be hand the other th of an inch pitch. Each end is provided with a nut
suitably tapped therefor. To fix the bolt, a nut is first run on the end screwed
with the finer pitch leaving about the thickness of a nut between its outer face
and the end of the bolt. The other end of the bolt is then passed through the
parts which are to be fixed together and is entered within the nut suitably tapped
therefor. The bolt is then screwed up, by means of the square or other shaped
part thereon as aforesaid, and on account of the difference in the pitches of the two
threads the nuts are drawn tightly together, firmly holding the parts between
them. If the pitches are respectively 10th and 14th of an inch, then 10 revolutions
of the bolt are necessary to draw the nuts together inch. In fixing bolts and
nuts constructed as above described it is necessary that both the nuts should be
tb

page_text: prevented from turning. This is effected in the case of a railway joint by
employing an ordinary channel fish plate on both sides of the joint or by
employing the ordinary channel fish plate on one side and tapping the fish plate on
the other side to answer as the nut at one end; or a channel washer or washers
may be used for the corresponding ends of two or more bolts in lieu of a channel
along one or both of the fish plates. These channel washers will of course answer
also in the case of bolts constructed as before described when used generally. Any
convenient means may however be employed to prevent the nuts from turning.
Bults and nuts constructed and fixed as above described have the ordinary
tendency of a bolt to turn in a nut when shaken reduced very considerably by
renson of the differential threads, the bolt also is the only part which can turn by
any possibility, and this, not only in itself, from its lesser diameter, has less
tendency to turn than has a nut, but to any such tendency there is opposed the
double friction occasioned by two nuts,
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Howarth in the Great Seal Patent Office on the 10th May
1883.
ROBERT HOWARTH of Wolverhampton in the County of Stafford "IMPROVE-
MENTS IN BOLTS AND NUTS AND IN THE METHOD OF FIXING THE SAME "
This invention relates specially to the bolts and nuts employed for securing the
fished joints of railway rails, and has for its object the complete prevention of the
bolts from working loose under the jarring action of the traffic. The invention is
however applicable to bolts and nuts used in other positions rendering them subject
to vibration.
This invention, as applied specially to railway joints, is illustrated by the
accompanying drawings. Figure 1 is a transverse section through a double-headed
rail joint, shewing one of the bolts thereof, with two nuts upon such bolt, in
section also, and figure 2 is a detached elevation of such bolt and nuts, with the
nuts approximately in the position, in relation to the bolt, due to the bolt being
about to be screwed up in place.
The same letters of reference occurring upon both these views indicate
corresponding parts.
AA is an ordinary double-headed rail; B B are fish-plates, each formed with a
groove or channel a along the outer side thereof; CD is one of the bolts
employed to tighten the fish-plates to the rail; E F are square nuts, ono on each
end of the bolt; and G is a square, triangular, or other shaped part, on the bolt, of
such a diameter in transverse section, as to allow the nut at the same end of the
bolt to be readily passed over it. The broken line on each figure indicates the
centre of the bolt between the two ends of the cylindrical part thereof.

page_text: As will be seen from the illustrations, the bolt CD has no enlarged head. The
nut F in effect takes the place of the ordinary bolt-head. A thread, having the
same direction in each case (that is either a right-hand or a left-hand thread) is run
on from each end of the bolt for the required distance towards the centre thereof,
but the two sets of threads are differential to one another, that is to say, the thread
upon the part D is of a finer pitch than that upon the part C, the former being say.
ten threads to the inch for a 3/4 inch diameter bolt and the latter say nine threads.
to the inch. The nuts are of course tapped to suit the threads at their respective
ends of the bolt. In the illustration the threads are shewn to be formed up to one
another in the centre of the bolt, though it is not necessary for the end C to be
screwed so far down the bolt, To fix the bolt in place the nut F is first run on so
far as to leave just about enough of the bolt projecting from its inner face to pass
through the parts which are to be held together. The bolt is then pushed through
such parts bringing the nut F within one of the grooves a, as shewn at figure 1,
the nut being thus securely prevented from turning. The nut E is then held in
position in the other groove a which prevents it from turning, and the bolt is
screwed up by means of a spanner on the part G. As this is done the bolt is
screwed through both the nuts, and the differential screws draw the nuts tightly
together, firmly holding the parts between them. If the pitches of the respective
threads are as given in the instance above referred to, then ten revolutions of the
bolt are necessary to draw the nuts together th of an inch. The thread at the
point of the bolt is preferably screwed somewhat taper (that is, lessening in
diameter) so as to facilitate its being entered within the nut E.
Instead of employing a nut at each end of the bolt, as shewn by figures 1 and 2,
an ordinary plain fish-plate may be used along one side of the joint and be tapped
to receive the ends of the bolt in lieu of the nuts otherwise required along that side.
This arrangement is illustrated by figures 3 and 4, of which figure 3 is a corre-
sponding cross section to figure 1, but is shewn as through a flange-rail joint, and
figure 4 is a side elevation of such joint one end thereof being broken short for
convenience of illustration. The same letters of reference occurring upon both
these views indicate corresponding parts. A' is the rail, B¹ B" the fish-plates and
C' D' the bolt. F' is the nut corresponding to the nut F, figure 1, three of such
nuts appearing in the part side elevation figure 4. The nut E, figure 1, is shewn
to be dispensed with, and in lieu thereof the fish-plate B' is tapped to receive the
end C of the bolt. The fish-plate B" may be grooved to keep the nut F' from
turning, or a grooved washer H', as shewn, and forming a continuous washer for
the corresponding ends of two or more bolts, may be employed for this purpose.
These grooved washers may of course be employed in lieu of the grooves a a
(figure 1) if desired.
•
Figures 5 and 6, being corresponding views to figures 3 and 4, except that one
bolt end only is shewn at figure 6, illustrate an arrangement of single washers for
preventing the nuts from turning. K K are the washers and have their sides c c
turned up, as shewn, to hold the nuts from turning The lower edges of the
washers abut upon the rail flange and are thus themselves prevented from turning.
These washers may be used in any position in which one side can be made to abut
against a flange or other unyielding part.
As no spanner is applied to the nuts, the sides may be chamfered as shewn at
figure 7, and the nuts thus be made lighter.
When the bolts and nuts, as described, are used for other purposes besides
railway joints, channel washers may be used to keep the nuts from turning; or the
bolls may be employed in any manner analogous to the modifications described for
1:olding together the fish-plates aforesaid; or when a nut or nuts are employed in
conjunction with a bolt constructed as aforesaid, and either for the purpose of a
railway joint or otherwise, any convenient means may be adopted to prevent the
nuts from turning.
Bolts and nuts constructed and fixed as above described have the ordinary
tendency of a bolt to turn loose in a nut when shaken reduced very considerably

page_text: by reason of the differential threads, which give all the advantage in this respect
of a very fine pitch indeed without the weakness incidontal thereto; the bolt alone.
is the only part which can turn by any possibility, and this, not only on account
of its mass being near to its axis, but on account of its lesser diameter also, has less
tendency to turn than has a nut, and to any such tendency there is opposed the
double friction occasioned by two nuts.
Fish-plates grooved to prevent the heads of ordinary bolts from turning have
been employed before and I do not of course make any claim to the fish plates
themselves.
Having fully described my invention, what I desire to claim and secure by
Letters Patent, is :-
•
First: The differentially screwed bolt, with a nut at each end thereof, in com-
bination with means for screwing up such bolt and preventing such nuts from
turning thereon when the bolt is screwed up, substantially as and for the purposes
herein described and shewn by the drawings.
Second-The differentially screwed bolt with a nut at one end thereof in com-
bination with means for preventing the same from turning on the bolt when the
bolt is screwed up, and with a tapped plate or other part, also incapablo of turning
upon the bolt when screwed up, at the other end, in combination with means for
screwing up such bolt, substantially as and for the purposes herein described.
Third The differentially screwed bolt in combination with a plate or other part
at each end incapable of turning upon the bolt when screwed up and means-for
screwing up the bolt, substantially as and for the purposes herein described.
In Witness whereof, I, the said Robert Howarth have hereunto set my hand
and Seal this ninth day of May in the year of our Lord one thousand
eight hundred and eighty three.
ROBERT HOWARTH,- (L.§:)· -
Witness:-
JOHN THOM
Clerk to Stephen Watkins, Assoc. M. Inst. CE.
Office for Patents.
-Wolverhampton¯