Improvements in Lock Nuts and Bolts.
Year: 1889

page_text: Date of Application, 21st Aug., 1889
Complete Specification Left, 20th May, 1890-Accepted, 5th July, 1850
PROVISIONAL SPECIFICATION.
Improvements in Lock Nuts and Bolts.
Communicated from abroad by ARCHIBALD KEIR LEITCH, of Great Valley Estate,
Deltotte, Ceylon, Planter.
I, WILLIAM RICHARD MIDDLEMORE THOMSON, of 96 Buchanan Street, Glasgow,
Lanarkshire, Engineer and Patent Agent, do hereby declare the nature of my
Invention to be as follows:-
The improvements of this Invention consist first in screwing the point of the
bolt, on which the lock-nut works, in the opposite direction to and of a smaller
diameter than the real tightening-up screw thread of the bolt fitting the tightening-
up nut; and second, in forming the female screw of a portion of the outer end
of the tightening-up nut, into which a male screw on the lock-nut works, also in
the reverse direction to the real tightening-up female screw of the nut, and of
the same angle and pitch as the lock screw on the point of the bolt, and pre-
ferably of the same diameter or larger than the said tightening-up female screw.
Thus if the tightening-up screw on the bolt and tightening-up nut are right-handed
screws, then the lock screw on the point of the bolt and in the outer end of the
tightening-up nut, would be left-handed, and vice versa would be right-handed on
a left-handed screw bolt and nut, and both of the same angle and pitch and in
the same axial line. The third improvement consists in screwing the female-screw
in the lock-nut with a screw to fit the male lock screw on the point of the bolt, and
hag also a male screw of the same angle and pitch on the outer surface of its inner
end screwed to fit the female lock screw in the outer end of the tightening-up nut,
with a shoulder on it truly formed or turned to fit the outer end of the tightening-
up nut; so that when the tightening-up nut is fully screwed up in one direction
by its screw key and held on, the lock-nut would be screwed up on the point of the
bolt in the opposite direction and at same time into said nut by its screw key until the
shoulders of the two nuts were tightly jammed together, which would lock both nuts
together and on the bolt, so that neither could turn loose or come off the bolt even if
the bolt got loose in the parts it was securing, until the lock nut was turned by some
person taking a screw key or keys to loosen the one nut from the other; all in con-
tradistinction to the usual lock or jam nuts, which, though tightened or jammed on
each other, may both get loose and turn off the bolt. By another modification, the
lock screw on the tightening-up nut might be formed as a male screw on its outer
end concentric to the inner tightening-up screw, and consequently have both the lock
threads in the lock-nut formed as female screws, in the same direction and of the same
angle and pitch, to fit the lock thread on the point of the bolt and that on the outer
end of the tightening-up nut. A slight play would be left between the reverse
angled threads of the tightening up screws and the lock screw of the bolt and of
both nuts to ensure the perfect tightening of the bearing surfaces of the two nuts when
screwed up.
When extra security is desired, a small screw pin may be inserted
laterally through either the tightening-up nut, or the locking nut, at the part of these
where they are formed with the internal reverse angled locking thread, the screw pin to
be tightened after the two nuts are screwed up tight together, and the thread may
be turned off the male screw in the form of a groove where the point of this pin
acts on.
Dated the 20th August 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in Lock Nuts and Bolts.
Communication from abroad by ARCHIBALD KEIR LEITCH, of Great Valley Estate,
Deltotte, Ceylon, Planter.
I, WILLIAM RICHARD MIDDLEMORE THOMSON, of 96 Buchanan Street, Glasgow,
Lanarkshire, Engineer, and Patent Agent, do hereby declare the nature of my
invention to be as follows:-
In order that my said Invention, and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory Sheet of Drawings in which the same reference letters
are used to indicate corresponding parts in all the figures where shown. Figure 1
is an elevation of a screw bolt A, as formed in accordanee with my improvements
with the threads of the locking screw stem A" at the outer part in the opposite
direction to, and of a smaller diameter than the screw thread at the inner tightening-
up part A. Figure 2 is an elevation of a similar screw bolt to Figure 1 only having
a square or oblong shoulder and round head, to fit into a correspondingly shaped hole
in one or both of the parts to be united, instead of having a round shoulder and
hexagonal head as in Figure 1. Figure 3 shows an elevation and transverse vertical
section of a tightening-up hexagonal sided screw nut B, as formed in accordance with
my improvements with duplex right and left hand internal screw threads B¹, B, the
tightening-up screw B¹ fitting the screw A¹ of the bolt A. Figure 4 shows an eleva-
tion and transverse section of a hexagonal sided lock nut C as formed in accordance
with my improvements with an internal female threaded screw C₁ to fit the male lock
screw A on the point of the bolt A, and with an external male threaded left hand
screw C² on the outer surface of its inner end to fit the female lock screw B", in the
outer end of the tightening-up nut B. Figures 5 are views of a tightening-up nut
similar to Figure 3, only having the female lock screw B" at the outer end made
of larger diameter. And Figures 6 are views of a lock nut C₁ similar to C
Figure 4, except that the outer screw thread part C2 is made of larger diameter
to fit the larger hole and thread B" formed in the tightening-up nut B shown in
Figure 6. Figures 7 and S are views of a tightening-up nut B and lock nut C¹
respectively corresponding to the transverse vertical sections shown in Figures 5 and 6,
but shown with an additional pinching screw d for further safety in locking the outer
lock nut to the tightening-up nut B.
Referring to these Drawings:-The improvements of this invention consist, first, in
screwing the point A" of the bolt A, on which the lock-nut C works, in the opposite
direction to and of a smaller diameter than the real tightening-up screw A¹ of the
bolt A fitting the tightening-up nut B; and, second, in forming the female screw B"
of a portion of the outer end of the tightening-up nut B, into which a male screw C¹²
on the lock nut C works, also in the reverse direction to the real tightening-up female
screw B¹ of the nut B, and of the same angle and pitch as the lock screw A" on the
point of the bolt A, and preferably of the same diameter as the tightening-up screw B¹
as shown in Figure 3, or larger as shown in Figure 5. Thus if the tightening-up
screw A¹ on the bolt A, and that B¹ on the tightening-up nut B are right handed
screws, as shown in Figures 1 to 3, then the lock screw A", on the point of the
bolt A, and that B", in the outer end of the tightening-up nut B, would be left-
handed, and vice versa would be right-handed on a left-handed screw bolt and nut, and
both of the same angle and pitch and in the same axial line. The third improvement
consists in screwing the female screw C" in the lock-nut C, with a screw to fit the
male lock screw A on the point of the bolt A and having also a male screw C² of
the same angle and pitch on the outer surface of its inner end screwed to fit the
female lock screw B₁i in the outer end of the tightening-up nut B with a shoulder c
on it truly formed or turned to fit the outer end of the tightening-up nut B; so that
when the tightening-up nut B is fully screwed up in one direction by its screw key

page_text: and held on, the lock-nut C would be screwed up on the point A" of the bolt A in
the opposite direction and at same time into said nut B by its screw key until the
shoulder c of the lock-nut C came tightly down on the outer end or shoulder b, of the
nut B, so as to lock both nuts together in opposite directions on the bolt A, and thus
prevent either from turning loose or coming off the bolt A even if the bolt got loose
in the parts it was securing, until the lock nut C was turned by some person taking a
screw key or keys to loosen the one nut from the other; all in contradistinction to the
usual lock or jam nuts, which, though tightened or jammed on each other, may both
get loose and turn off the bolt. By another modification, the lock screw B" on the
tightening-up nut B might be formed as a male screw on its outer end 6¹ concentric
to the inner tightening-up screw B¹ and consequently have both the lock threads C", C³,
in the lock-nut C formed as female screws, in the same direction and of the same angle
and pitch, to fit the lock thread A¹ on the point of the bolt A and that at 6¹ on the
outer end of the tightening-up nut B as shown in sectional elevations in Figures 9
and 10. A slight play would be left between the reverse angled threads of the
tightening-up screw A₁ and the lock screw A" of the bolt A and of both nuts B, C,
to ensure the perfect tightening of the bearing surfaces b, c, of the two nuts B, C,
when screwed up. When extra security is desired, as shown in Figures 7 and 8, a
small screw pin d, may be inserted laterally through either the tightening-up nut B,
or the locking nut C, at the part of these where they are formed with the internal
reverse angled locking thread, the screw pin d to be tightened after the two nuts BC
are screwed up tight together, and the thread may be turned off the male screw at ď¹
in the form of a groove where the point of this pin d acts on.
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. The construction or arrangement and combination of the parts of tightening-
up nuts, lock nuts and bolts with duplex right and left hand threaded screws, sub-
stantially as and in the manner and for the purposes herein described, in reference to
and shown in the accompanying Drawings.
Second. The construction and use of screw lock bolts with the threads at the outer
part screwed in the opposite direction to and of a smaller diameter than the tightening
up screw threads at the inner part, substantially as and for the purposes herein
described, in reference to and shown in the accompanying Drawings.
Third. The construction and use of tightening-up nuts with duplex right and left
hand screw threads, the female screw into which the male screw of the lock nut works
being formed in the reverse direction to the tightening-up female screw of the nut,
substantially as and for the purposes herein described, in reference to and shown in
the accompanying Drawings.
Fourth. The construction and use of lock nuts formed with an internal threaded
female screw to fit the male lock screw on the point of the bolt, and also with an
external threaded male screw of the same pitch and angled thread on the outer surface
of its inner end, to fit the female lock screw in the outer end of the tightening-up nut
or have this also an internal screw to fit a male screw on the nut, substantially as
and for the purposes herein described, in reference to and shown in the accompanying
Drawings.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.