Improvements relating to Lock-nuts for Screw-threaded Bolts.
Year: 1887

page_text: Date of Application, 15th Mar., 1887
Complete Left, 14th Jan., 1888
Complete Accepted, 9th Mar., 1888
PROVISIONAL SPECIFICATION.
Improvements relating to Lock-nuts for Screw-threaded Bolts.
I. ALFRED BUCKINGHAM IBBOTSON, of Ibbotson, Brothers & Co., of Globe Steel
Works, Sheffield in the County of York do hereby declare the nature of this inven-
tion to be as follows:-
My invention relates to lock-nuts for screw-threaded bolts, and is chiefly designed
for use in connecting or securing the ends of railway rails, and for analogous
purposes; the said nuts being adapted to hold tightly and securely upon the bolt
(as hereinafter described) without the aid of any separate locking device or appliance.
According to my said invention, several of the threads at one end of the bolt-hole
in the nut are (by means of compression applied to the top or face of the latter,
vertically in the direction of the bolt-hole therein) caused to occupy a position nearer
to each other than is the case with the remainder of the threads, but the threads so
brought nearer together or flattened are compressed comparatively evenly all around
the same, and are not indented or mutilated, that is to say the pitch of these few upper
threads is, by the said compression, reduced as compared with that which was given
to them when the nut was tapped, and as compared with the pitch of the remainder
of the threads. The effect of the compression according to my present invention is,
therefore, to produce a nut with threads having a differential pitch, the object being
to provide means whereby, when the nut is screwed upon the bolt with which it is to
be used, a tight frictional grip will be produced between these male and female threads
sufficient to prevent separation thereof by reason of vibration or any similar action,
and yet without distorting the threads of the nut or of the ordinary bolt.
I will now proceed to describe the nature of the means I employ for carrying my
said invention into practice. I first make the nut in the ordinary manner, that is to
say, with the whole of its female screw-threads parallel and of such a pitch as to fit,
or coincide with, the male screw-threads upon the bolt with which the said nut is to be
used, and I then compress some of these female threads in the said nut by the applica-
tion of sufficient force in the direction of the bolt-hole upon one of its faces, as
hereinafter described. In order to effect the compression of the threads, I place the
nut upon a solid bed which firmly supports it, and I insert within the screw-threaded

page_text: hole of the nut a circular parallel metal (preferably steel) mandrel which extends
from above or from below, and either completely or partially through the said hole,
and is of such diameter that the edges of the threads of the nut are in close, or nearly
close, contact with its periphery. The lower end of the mandrel may rest upon the
surface of the bed, in which case it will be flush with the bottom of the nut; but it is
preferable to secure this end of the said mandrel within an aperture in the bed so that
it will be held firmly therein and will project vertically therefrom in such a manner
that the nut can be readily slipped over it when the compression is to be effected, and
can be as readily removed therefrom when this has been accomplished. The length of
the said mandrel may be such that its upper end will reach exactly to, and be flush
with, the upper surface of the nut before compression and slightly beyond it after
compression, a suitable hole or space being provided in the compressing tool to admit
the projecting end. But I prefer that it shall extend a short distance above this
surface so as to form a gauge or stop for determining or regulating the amount of
compression applied at this point, a recess, in this case, being made in the lower face
of the compressing fool just deep enough to receive the projecting end of the mandrel.
The nut having been placed upon the bed as described a punch or other suitable tool
is applied with sufficient force and in any desirable manner to the upper surface of
the nut to cause the metal to be compressed and some of the threads to be flattened or
forced nearer together so that when this nut comes to be screwed upon the ordinary
bolt, force will be required to cause the threads of the latter to engage with the portion
of the nut so treated, and consequently the bolt and nut will be securely locked
together without the necessity for applying any separate part or piece for this purpose.
When the threads of the bolt engage with those threats of the nut which have been
compressed as above described, the effect is that the said compressed threads are
gradually and regularly separated or widened out so that no distortion of the threads
of the bolt is produced, but at the same time the frictional contact between these
threads and those of the nut is amply sufficient to prevent the separation of the nuts
and bolts through vibration or similar action to which such fastenings are exposed in
use. In order that the action of the bolt in expanding the compressed threads may
be more certain I prefer to use bolts made of hard metal and to make the nuts of
somewhat softer metal.
In some cases the mandrel will be provided with screw-threads for a part of its
length, that is to say, it will be screw threaded for a sufficient distance to fit, and
preserve from compression, those threads of the nut which are not intended to be
compressed, the remainder of the shaft of such mandrel being plain or unscrewed and
of such diameter as to accurately fit or fill the diameter of the hole between the
edges of the threads to be compressed; And to prevent the rapid wearing of such
screw threads on the mandrel I may turn off the thinnest portions thereof so that they
do not entirely extend to the bottom of the spaces between the female threads of the
nut, but effectually prevent the compression of the pitch of such threads. This
mandrel may be provided with a square or other suitably shaped head having some
flat external surfaces which will serve, not only for conveniently turning the mandrel
into and out of the nut, but can also be made to serve as the die or bed for supporting
the nut while under compression, and the said head may be inserted within a hole or
slot in the bed of the pressing machine.
In some cases the mandrel shaft may be formed with only a screw threaded portion,
that is to say without a plain or unscrewed portion, and may be placed in, and held
by, a gate or tool on the bed of the pressing machine exactly in the proper position
to ensure the entry of a fixed plain unscrewed projecting rod of the correct diameter
to fit and pass easily through the inner diameter of the threads that require to be
compressed in the nut, and extending from the exact centre of the compressing tool
into the hole at that end of the nut where the compression is to take place. This rod
may be of such a length that when it is inside the nut there will be a space between
it and the upper end of the mandrel, but when the compression has been effected the
end of the mandrel and the end of the rod will touch each other, this space therefore
regulating the amount of compression.
°

page_text: The compressing tool may be made separately from the machine, and having a
suitable hole in its centre, may be placed by hand over the unscrewed or plain portion
of the rod or shaft of the mandrel which projects through and beyond the nut; or
the projecting rod in this compressing tool may be placed inside that end of the nut
where the threads are to be compressed and the whole three parts (nut, mandrel, and
compressing tool) may then be placed together upon the bod of the compressing
machine. The face of the separate compressing tool may be perfectly flat or of any
other desirable configuration. It may, in some cases, be so formed as to impart a
lateral pressure upon the rounded upper part of the nut (as well as a directly vertical
pressure) so as to reduce the diameter of the hole in the nut between the edges of the
compressed threads.
In order to ensure uniformity of pitch in the compressed threads of cach nut, and
consequent uniformity of grip upon the bolts, may employ an additional mandrel
formed with screw threads of the exact pitch desired in the compressed threads of
the nut and either with or without their edges or thinnest portions turned off.
the compression has been effected and the first mandrel removed, the nut is forced
After
upon this additional mandrel by screwing up thereon that portion of the nut containing
the compressed threads, which thus have imparted to them a uniformity ensuring the
exact gripping power desired. The additional mandrel may in some cases be inserted
within the nut before the other mandrel is withdrawn.
In some cases I may dispanse with the use of the mandrel, placing the nut upon
the bed of the machine and applying the compressing tool at the top as above
explained.
The nut may be compressed either whilst hot or cold.
HASELTINE, LAKE & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements relating to Lock-nuts for Screw-threaded Bolts.
1, ALFRED BUCKINGHAM IBBOTSON, of Ibbotson Brothers & Co. Limited, Globe
Steel Works, Sheffield, in the County of York, 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:-
My invention relates to lock-nuts for screw-threaded bolts, chiefly designed for
securing railway rails at their joints and for analogous purposes, the said nuts
having their screw-threads so formed that they will, without the aid of any separate
locking devices or appliances, have a secure and permanent grip or hold upon the
bolts to which they are applied, as described in the Specifications of former Letters
Patent dated 18th April 1877, No. 1508, and 11th December 1878, No. 5082.
According to one part of the invention described in the said former specification
No. 5082, this result is obtained by making the screw-threads of the nut with such
difference or interruption of pitch that they cannot, without the exertion of much
greater force than can be applied by the fingers alone, be screwed home upon the
bolt.
In the Complete Specification of my application dated 8th September 1886,
No. 11,438, I have described a method of reducing the diameter of some of the
threads of a screw-nut by the application of external pressure (in directions transverse
to its axis) at or near one end of the nut, while the said nut is upon a tapered screw-
threaded mandrel, which, although it permits the required reduction of the diameter
of the threads in the nut, prevents distortion of the said threads or alteration of their
pitch, depth or width.
Now my present invention is designed to provide for the production of lock-nuts
with screw-threads having a difference or interruption of pitch as described in the said
former Specification No. 5082, that is to say, with some or most of its threads of the
same pitch as those of the bolt with which it is to be used, and the remainder of its
threads of a reduced pitch.
In making a lock-nut according to my present invention, I first tap the same in
the ordinary manner with parallel screw-threads adapted to properly fit the bolt with
which the said nut is to be used. I then reduce the pitch of a few of the threads in
one end of the nut by the application of endwise pressure to the same while the nut
is upon a plain mandrel which will prevent the lessening of the internal diameter of
such nut or of its threads, or while the nut is upon a screwed mandrel which will
likewise prevent diminution of the internal diameter of the threads and will also
prevent any alteration in the pitch of such of the threads as require no alteration, as
hereinafter described. I then, if desired, ensure uniformity of pitch of the compressed

page_text: threads by inserting in the nut a mandrel having screw-threads which are an exact
counterpart of the compressed threads to be formed in the nut.
In the accompanying drawings.
Figure 1 shows, in sectional elevation, a nut placed on the bed of a pressing
machine under a pressing tool as hereinafter described.
Figure 2 is a similar view showing a modification of my invention.
The remaining Figures are hereinafter referred to.
I prefer to make the nut a with a circular projection around the hole thereof at a¹,
that is to say, at the end which is to he compressed.
To effect the compression,
1 place the said nut, after the ordinary or parallel screw-threads have been formed
therein, upon the solid bed or anvil e, as shown in Figure 1, a steel or other
mandrel which is supported in the bed e, being introduced into the screw-threaded
hole of the nut, and the said nut being, by preference, previously heated at the end
which is to be compressed. I then force the die or pressing tool down upon the
top of the nut, thereby compressing the upper end thereof. The die may he
operated by hydraulic or other power. The mandrely shown in Figure 1 is plain
or cylindrical and of such diameter that the edges of the threads of the nut are in
contact with, or in close proximity to its periphery. The mandrel is supported and is,
by preference, secured in the bed e, and projects vertically therefrom, so that the
nut can be readily slipped over it when the compression is to be effected and can be
readily removed therefrom after the compression. The said mandrel is preferably of
such length that its upper end will reach exactly to, and be flush with, the upper
surface of the nut before compression, and will extend slightly beyond it after
compression, a suitable hole or cavity being formed in the compressing tool or
die to admit the projecting end of the mandrel as shewn. The said mandrel,
therefore, serves as a gauge or stop for determining or regulating the amount of
compression applied to the mm. Or, as shown in Figure 2, the plain mandrel may be
a short one projecting from the compressing tool /
In some instances, the mandrel g is provided with screw-threads for a part of its
length, as shown in Figures 3, 4 and 5, so that it will fit and preserve from
compression those threads of the nut which are not intended to be compressed, the
plain or unscrewed portion of the mandrel, shown at g² in Figure 3, being of such
diameter that it will be in contact with, or in close proximity to the edges of the
threads to be compressed. The mandrel is, moreover, in some instances, formed
with a square or other flat-sided head gas shown in Figures 3, 4 and 5, which will
serve for conveniently turning the mandrel into and out of the nut.
To prevent the rapid wear of the screw-threads on the mandrel, I sometimes turn
off the thinnest portions or edges of the said threads, as showngati in Figures and 5,
so that they do not entirely fill the spaces within the female threads of the nut, and
yet will effectually prevent the compression or reduction of the pitch of such
threads.
In some cases, the mandrel g is formed with a screw-threaded portion only, which
also extends only partially through the nut, as shown in Figures 4 and 5, and the
pressing die or tool may be formed separately from the machine with a plain or
unscrewed projecting pin or mandrel as also shown in Figures 4 and 5, of the
correct diameter to fit and pass easily between the inner edges of the screw-threads
to be compressed. This pin or rod should be of such length that, when it is
introduced into the nut, there will be a space between it and the upper end of the
mandrel g, as shown in Figure 4, but, when the compression has been effected, the
end of the said mandrel and the end of the said pin or red will touch each
other as shown in Figure 5, thus regulating the amount of compression. Or the
sid compressing tool may be formed as a separate piece from the compressing
machine with a hole therein, as at in Figure 3, of the correct size to permit the
plain projecting end of the mandrel to pass through, or into it as shown in
Figure 3. If desired the hole 13 may extend only so far into the compressing tool
hat, as soon as the required compression has been given to the threads to be

page_text: compressed, the end of the said hole will come in contact with the mandrel and
further downward movement of the compressing tool will thus be prevented.
By the compression of the nut as above described, a difference or interruption
of pitch is obtained such as is described in the said former specification No. 5082,
that is to say, some of its threads are flattened or forced nearer together, so that,
when the nut is screwed upon an ordinary bolt, much greater force will be required
than can be applied by the fingers alone to cause the compressed threads of the nut
to engage with the threads of the bolt, and consequently the bolt and nut will be
securely locked together without the necessity for applying any separate device or
appliance for this purpose. When the compressed threads of the nut engage with
the threads of the bolt, in the act of screwing the nut thereon, the said compressed
threads are gradually and regularly separated or widened out, therefore no distortion
of the threads of the bolt is produced and yet the frictional contact between these
threads and the compressed threads of the nut is amply sufficient to prevent the
separation of the nut and bolt through vibration or similar action to which such
fastenings are exposed in use. In order that the action of the bolt in expanding the
compressed threads may be more certain, I prefer to use bolts made of hard metal
and to make the nuts of somewhat softer metal.
In some instances, in order to ensure uniformity of pitch of the compressed threads
of the nuts, and consequent uniformity of grip upon the bolts, I employ an additional
mandrel and by preference one with a square or flat sided head, as shown in side
elevation in Figure 6. This mandrel is formed with screw-threads which are an exact
counterpart of the flattened or reduced threads required to be formed in the nut.
screw-threads of this mandrel may be formed with sharp edges as shown in Figures 6
The
and 7, or they may have their edges or thinnest portions turned off as shown in
Figure S. After the compression has been effected as above described and the first
mandrel (Figures 1 to 5) has been removed, this additional or finishing mandrel /
is screwed into that portion of the nut containing the compressed threads, which have
thereby imparted to them a uniform pitch throughout; so that the exact gripping
power desired may be ensured. The additional mandrel h may, in some cases, be
inserted within the nut before the other mandrel is withdrawn therefrom.
"
The nut may be compressed either whilst hot or cold.
My present invention affords the means for very advantageously making "Ibbotson"
lock-nuts adapted for use with the improved bolts described in the Specification of
British Letters Patent granted to me and dated August 13th 1886, No. 10,402.
It is evident that I can, if desired, take ordinary screw-nuts and convert them into
lock-nuts in the manner hereinbefore described.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed I wish it understood that
I claim :-
--
First. The manufacture of a lock-nut by vertical or endwise compression of some
of the threads of a screw-nut, while diminution of the internal diameter of its threads
is prevented by means of a mandrel, as described with reference to Figure 1 or to
Figure 2, in such a manner as to diminish the pitch of a few of the screw-threads of
the said nut without altering their internal diameter, substantially as hereinbefore
described.
Second. In the manufacture of a lock-nut by the vertical or endwise compression of
some of the threads of a screw-nut, the employment of a screw-threaded mandrel
having either full screw-threads as shown in Figure 3, or screw-threads the thinnest
portions or edges of which are turned off as shown in Figures 4 and 5, (with or 5
without a flat-sided head or base gl and with or without the projecting unscrewed
portion g²), all substantially as, and for the purposes, set forth.
Third. The employment, in combination with a screw-threaded, or
screw-threaded and partially plain, or a plain mandrel on which the nut is to be
a partially
placed, of a compressing tool made separately from the pressing machine and

page_text: formed either with a hole as aɩ ƒ³ in Figure 3 extending partially or wholly through
it to permit the projecting plain portion 2 of the mandrel to pass into the same, or
with a projecting pin, as at in Figures 4 and 5, substantially as, and for the purposes,
set forth.
Fourth. The improved method of ensuring uniformity of the compressed threads by
means of a screw-threaded mandrel h having either full screw-threads as in Figures 6
and 7, or screw-threads the thinnest portions or edges of which are turned off as in
Figure 8, substantially as, and for the purpose, set forth.
Fifth. The above described method of manufacturing a lock-nut, consisting in
heating one end of a screw-nut, compressing some of the threads therein and then
forcibly screwing a mandrel h into the compressed end of the said nut, substantially
as, and for the purpose, set forth.
LFRED BUCKINGHAM IBBOTSON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.