IMPROVEMENTS IN SCREW BOLTS AND LOCK-NUTS FOR THE SAME
Year: 1881

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN SCREW BOLTS AND LOCK-NUTS FOR THE SAME." A com-
munication from abroad by Charles Halbert Denison, Counsellor at Law,
and Erastus Frelinghuysen Mead, Merchant, both of the City and State of
New York, United States of America.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 28th June 1881.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. "IMPROVEMENTS IN SCREW BOLTS AND
LOCK-NUTS FOR THE SAME." [A communication from abroad by Charles Halbert
Denison, Counsellor at Law, and Erastus Frelinghuysen Mead, Merchant, both of
the City and State of New York, United States of America.]
This Invention relates to that class of screw bolts with which a jam-nut is used
to prevent the displacement of the ordinary nut by jarring, or from other causes,
the object of such devices being that when the last named nut is brought home to
its place it may be there retained against all the ordinary vicissitudes of use, as,
for example, when applied to the joints of railway rails, and the like.
The said Invention comprises a novel combination of parts whereby any
tendency to a reverse movement on the part of the ordinary nut tends only to hold
the jam-nut more firmly in its place and thereby prevent the nut itself from
turning or moving from its proper position.
In carrying the said Invention into practice I construct a bolt provided at one
end with the usual head, and it is also provided with the usual screw-threaded
portion, upon which is placed a nut of the ordinary kind. Upon that end of the
bolt which is opposite to the head I provide a shank, which in its cross section is
cam-shaped or excentric in form. I also provide a jam-nut having the external
configuration of the ordinary nut in order that it may be conveniently turned
Price G1

page_text: with a wrench, and having its bore or interior of a cam or excentric shape, corre-
sponding to the cross section of the shank of the bolt, so that it may be slipped
upon the said shank.
The ordinary or screw-threaded nut being brought to the
requisite position upon the threaded portions of the bolt, the jam-nut is slipped
upon the shank until its inner face is brought snugly against the adjacent face or
outer end of the ordinary nut. This done the jam-nut is turned axially; the cam-like
or excentric shape of the shank acting in conjunction with the corresponding
internal contour of the jam-nut binds the latter upon the shank with a frictional
hold of very great power, so that the longitudinal movement of the jam-nut upon
the shank is practically impossible, and the twist or direction of the screw-thread
being such that the nut in turning off from this screw-thread will move in the same
direction as the jam-nut moves in being brought to bite or hold upon the shank
as just explained, it follows that the said nut in any tendency to turn off from the
screw-thread only binds the closer upon the jam-nut, and its only action upon the
said jam-nut is to hold or bind the same tighter upon the shank so that the longi-
tudinal movement of the said jam-nut being prevented, the turning or outward
movement of the other nut is in like manner rendered impossible.
It is preferred that the cam-shaped or excentric bore or interior of the jam-nut
be smooth, inasmuch as this permits its adjustment longitudinally upon the shank
with extreme accuracy and to an infinitesimal fraction of space. In some cases
however it may be desirable that the shank should, so to speak, indent itself in
the internal surface of the jam-nut in order that the said jam-nut may have a
sharper bite or hold upon the said shank; to this end therefore the shank itself
may be formed with circumferential teeth, which may be either simply a con-
tinuation, somewhat flattened, of the thread, or it may consist of circumferential
parallel ridges or teeth formed upon the shank irrespective of the pitch of the
adjoining screw threads,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
28th December 1881.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
"IMPROVEMENTS IN SCREW-BOLTS AND
Agents, Southampton Buildings, London.
LOCK-NUTS FOR THE SAME." A communication from abroad by Charles Halbert
Denison, Counsellor-at-Law, and Erastus Frelinghuysen Mead, Merchant, both of
the City and State of New York, United States of America.
This Invention relates to that class of screw-bolts with which a jam-nut is used
to prevent the displacement of the ordinary nut due to jarring or other causes, the
object of such devices being to retain the last named nut in position when the
same is screwed home or to its place notwithstanding all the ordinary vicissitudes
of use, as, for example, when applied to the joints of railway rails and the like.
The said Invention comprises a novel combination of parts whereby any
tendency to a reverse movement on the part of the ordinary nut acts only to hold
the jam-nut more firmly in its place, and thereby prevent the nut itself from
turning or moving from its proper position.
In the accompanying Drawing
Figure 1 is a side view of a screw-bolt provided with the ordinary nut and with
a lock-nut according to the said Invention, and
Figure 2 is a longitudinal section of the said nuts with the bolt in side view.
Figure 3 is an end view of the same showing the manner in which the jam-nut
is placed upon the bolt, and
Figure 4 is a similar view showing the manner in which the jam-nut is tightened
upon the said bolt.
Figures 5 and 6 represent in longitudinal section and partly in side view certain
modifications of the said Invention.
A is the bolt provided at one end with the usual head a, and also provided with
the usual screw-threaded portion b, upon which is placed the nut B of ordinary
construction. Upon that end of the said bolt which is opposite to the head a is
provided a shank e¹, which, in cross section, is cam-shaped or excentric in form, as
represented in Figures 3 and 4. D is the jam-nut having the external configu-
ration of the ordinary nut in order that it may be conveniently turned with a
wrench, and having its bore or interior of a cam or excentric shape corresponding
to the cross section of the shank C' of the bolt A so that it may be slipped upon
the said shank C', as illustrated in Figures 1 and 3. When the nut B is brought
to the requisite position upon the threaded portion b of the bolt A the jam-nut
is slipped upon the shank C¹ until its inner face is brought snugly against the
adjacent face or outer end of the said nut B. The jam-nut D is then turned
axially in the direction indicated by the arrow in Figures 3 and 4, and the
cam like or excentric shape of the shank C¹ acting in conjunction with the corre-
sponding internal contour of the jam-nut D binds the latter upon the said shank C
with a frictional hold of very great power, so that the longitudinal movement of
the said jam-nut D upon the shank C' is practically impossible. Moreover as the
twist or direction of the screw-thread b is such that the nut B in turning off from
this screw-thread will move in the same direction as the said jam-nut D moves in
being brought to bite or hold upon the shank C', as just explained, it follows that the
said nut B in any tendency to turn off from the screw-thread b binds all the closer
upon the jam-nut D, and its only action upon the latter is to hold or bind the
same tighter upon the shank C₁, so that the longitudinal movement of the said
jam-nut D being prevented the turning or outward movement of the nut B is in
like manner rendered impossible.

page_text: :
In
It is preferred that the cam-shaped or excentric bore or interior of the jam-nut D
should be smooth, inasmuch as this permits its adjustment longitudinally upon the
shank C¹ with extreme accuracy and to an infinitesimal fraction of space.
some cases however it may be desirable that the shank C¹ should, so to speak,
indent itself in the internal surface of the jam-nut D in order that the said jam-
nut may have a sharper bite or hold upon the said shank; to this end therefore
the shank itself may be formed with circumferential teeth a², which may be either
simply a continuation,. somewhat flattened, of the thread b, as represented in
Figure 6, or it may consist of circumferential parallel ridges or tecth 6¹ formed
upon the said shank C₁ irrespective of the pitch of the adjoining screw-threads b,
as represented in Figure 5.
Having thus fully described the said Invention as communicated to me by my
foreign correspondents, and the manner of performing the same, I wish it understood
that I claim,
The bolt having the screw-thread b and cam-shaped or excentric shank C' in
combination with the nut B and with the jam-nut D having the cam-like or
excentric oore or interior corresponding in shape with the cross section of the
_said shank C' of the bolt, the said parts being constructed and arranged for joint
"use and operation, substantially as above set forth and for the purposes specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty eighth day of December, in the year of our
Lord One thousand eight hundred and eighty one.