Year: 1885

page_text: I WILLIAM HENRY LINDSAY of 14 South Wharf Paddington Basin in the
County of Middlesex Engineer do hereby declare the nature of this invention to be.
as follows:-
The object of this invention is to provide a more simple and efficient means of
locking screw nuts than those heretofore adopted. For this purpose I make the
bolt hollow at the end onto which the nut is to be screwed the hollow in the bolt
being made to extend a distance into that portion of the bolt which will be
surrounded by the nut when the nut is screwed up.
The outer end of the hole through the nut say for about half the thickness of
the nut I make to taper slightly outwards so that the mouth of the hole is of
slightly larger diameter than the centre.
The hole in the end of the bolt I also similarly make to taper slightly towards.
its mouth.
When the nut has been screwed on to the bolt the end of a tool similar to a
punch is to be placed into the hole in the end of the bolt and a blow given to it
with a hammer.
The end of the tool being of larger diameter than the inner end of the hole in
the bolt will then expand the bolt outwards within the tapered portion of the hole
through the nut.
In this way the diameter of the bolt is slightly enlarged in rear of the inner end
of the nut the diameter of the hole in which is less than the diameter of the hole
through the outer half of the nut so that it effectually prevents the nut from
screwing back along the bolt.
Or in place of or in addition to this means of retaining the nut-the nut might
at one end have a short longitudinal slit formed through it on one side and also a
transverse slit through about one half of the circumference of the nut meeting the
inner end of the longitudinal slit. This leaves about one half of the circumference
of the end of the nut detached from the remainder of the nut except at one end.
The free end of the strip so partially detached from the remainder of the nut
can then be set inwards slightly either by pressure or by a blow with a hammer.
When the nut is being screwed on to a bolt the inner edge of the end of the
strip so set inwards will scrape over but not cut into the bolt but after the nut has
been screwed on the inner edge of the strip will on any backward movement of
the bolt taking place at once cut into the bolt and prevent all further backward
movement.
Dated this 11th day of November 1885.

page_text: I WILLIAM HENRY LINDSAY of 14 South Wharf Paddington Basin in the
County of Middlesex Engineer 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 :—
It has before been proposed to form a conical hole in the end of a screw bolt and
to expand the end of such a bolt after a nut has been screwed on to it by driving.
into the conical hole a corresponding conical punch.
This way of locking a screw nut is only available when the bolt is accurately of
the length required so that but a small portion of the bolt extends beyond the nut
when the nut has been screwed up on to it-and does not admit of the nut should it
become slack being tightened up from time to time and again locked-moreover if
the bolt were of ordinary iron the driving in of the conical punch would split the
end of the bolt and render it impossible to forcibly screw back the nut should it be
desired to do so so that if from any cause the nut was required to be unscrewed
much difficulty would be experienced and both the nut and the bolt would be
spoilt for subsequent use.
According to my invention I form a cylindrical hole extending for some distance
into the end of the bolt and I lock the nut when it has been screwed up on to
the bolt by expanding a portion of the bolt which is within the nut without
expanding the bolt at its end and in this way avoid the splitting of the metal of
which the stem of the bolt is formed.
To avoid expanding the end of the bolt I make the mouth of the hole for a
depth say of about 1th of an inch of a larger diameter than the remainder of
the hole so that any plug or punch driven into the remaining portion of the hole
will not expand the end however far the tool or punch may be driven in.
Should a nut which has been locked in the above manner require at any time to
be tightened up and again relocked the tightening up of the nut can readily be
effected and by driving the punch or tool still further into the end of the bolt the
nut can be again locked.
The tightening up of the nut should it at any time become loose can be effected
with the exercise of but little force although it cannot be screwed back except by
the excrcise of considerable force because when the bolt is expanded the portion of
the nut surrounding such part of the bolt is also expanded-this does not materially
impede the nut from being screwed forwards but effectually impedes its being
screwed back because the forward end of the bolt being unexpanded has then to
screw back over the expanded portion of the bolt, this it can only do when a
spanner having a long lever arm is used to turn it back.
It is not essential that the hole in the bolt should be central although I prefer it
to be so it might however be somewhat to one side of the centre if desired.
Figure 1 is a side view and Figure 2 a longitudinal section of a nut and bolt
formed as above described so that the nut may be locked when it has been screwed
up on to it. Figure 3 shows a side view of a punch suitable for being used for
expanding the end of the bolt.
"

page_text: A is the hole in the end of the bolt, B the portion of the mouth of the hole
which is enlarged in diameter, this enlarged portion of the hole is made to extend
into the bolt for a distance equal to or somewhat greater than the length of the
bolt which it is intended shall protrude beyond the rear end of the nut when the
nut has been screwed up on to it to clip the plates or bars interposed between it
and the head of the bolt.
When so screwed up the portion C of the tool shown at Figure 3 is inserted into
the mouth of the hole A and by a blow with a hammer is driven into it so as to
expand the hole say to the depth of the dotted line D. E. the diameter of the
portion of the tool so driven into the hole A being of slightly larger diameter than
the hole.
For a bolt of the size shown in the drawing I prefer that the diameter of the
tool should exceed that of the hole by about of an inch.
When the tool has so been driven into the whole the diameter of the portion of
the bolt surrounded by the nut will have been increased up to the dotted line D, E
causing probably some increase in the diameter of the corresponding portion of the
hole in the nut, this does not materially interfere with the nut being screwed
forwards still further on to the bolt, but as above explained prevents the nut from
working back along the bolt so that should any wear or compression of the
materials between the nut and the head of the bolt take place and the nut con-
sequently become slack the nut may without difficulty be tightened up and be
again locked by driving the tool C. still further into the hole A.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. A screw bolt with a cylindrical hole formed in the end of the stem and with
the mouth of the hole enlarged for a distance into the bolt so as to admit of the
inner cylindrical portion of the hole being expanded without splitting the mouth
of the hole and of a nut screwed on to the end of the bolt being thereby locked
substantially as described.
2. The locking of screw nuts substantially in the manner hereinbefore described.
CARPMAEL & Co.,
Agents for the Applicant.