IMPROVEMENTS IN THE CON- STRUCTION OF SCREW NUTS FOR AXLE BOXES AND OTHER PURPOSES
Year: 1856

page_text: LETTERS PATENT to Frederick Peter Dimpfel, of the City and County of
Philadelphia, and State of Pennsylvania, one of the United States of
America, Engineer, for the Invention of "IMPROVEMENTS IN THE CON-
STRUCTION OF SCREW NUTS FOR AXLE BOXES AND OTHER PURPOSES."―A o m-
munication from Kingston Goddard, of the City of Philadelphia, in the
United States of America.
Scaled the 26th August 1856, and dated the 23rd May 1856.
PROVISIONAL SPECIFICATION left by the said Frederick Peter Dimpfet.
at the Office of the Commissioners of Patents, with his Petition, on the
23rd May 1856.
I, FREDERICK PETER DIMPFEL, of the City and County of Philadelphia, and
State of Pennsylvania, one of the United States of America, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
CONSTRUCTION OF SCREW NUTS FOR AXLE BOXES AND OTHER PURPOSES," to be as
follows:-
The object of the present Invention is to construct screw-nuts in such a
manner that they will not be liable to become unscrewed, or become loose
while in use, as is often the case with screw nuts of the ordinary kind.. For
the purpose of preventing this inconvenience, it has sometimes been considered
desirable to employ a small screw, which is made to pass through the nut into
the male screw inside. These small holding or securing screws are, however,
liable to become unscrewed and fall out, and, in fact, frequently do so, when
there is great danger of the screwed nut becoming loose, and ultimately coming
off, if not frequently attended to. In order to prevent this, the Inventor of

page_text: the present plan proposes to dispense with the transverse holding screw, before
imentioned, and to secure the nut by means of a small moveable excentric lever
or tooth, which is mounted on a centre on the flange of the nut, or of the
washers connected therewith. The end of this tooth is made to take into the
thread of the male screw cut on the end of the axle or bolt to which the nut is
intended to be applied. This moveable excentric lever is made in the form of
a small curved lever, having a tooth at its inner end; which is kept in the
thread of the screw of the axletree or bolt by means of a spring, which presses
against the tail of the excentric. The tooth of the excentric lever, by its
peculiar form, will prevent the nut from being turned back until the tooth is
withdrawn from the thread of the screw. This may be effected when required
by means of a pin or stud, which may be passed through the nut and made to
act against the end of the lever. If required, two of these holding teeth or
levers may be employed in conjunction, and being made to act in opposite
directions, will prevent the nut from being turned in either direction. This
may be required for set screws, or when applied to machinery which requires to
be accurately adjusted; but for axle boxes, one excentric holding tooth will be
generally found sufficient.
It is almost needless to observe, that this mode of constructing nuts may be
adapted not only to axletrees, .but to any purpose in machinery where it is
necessary that the nuts should be secured in any given position.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Peter Dimpfel in the Great Seal Patent Office
on the 22nd November 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
PETER DIMPFEL, of the City and County of Philadelphia, and State of
Pennsylvania, one of the United States of America, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of May, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Frederick Peter Dimpfel, Her special license that I, the said Frederick
Peter Dimpfel, my executors, administrators, and assigns, or such others as
I, the said Frederick Peter Dimpfel, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and

page_text: at all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF SCREW NUTS FOR AXLE BOXES AND OTHER
PURPOSES," being a communication from Kingston Goddard, of the City of
Philadelphia, in the United States of America, upon the condition (amongst
others) that I, the said Frederick Peter Dimpfel, by an instrument in writing
under my hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Peter Dimpfel, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement,, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
This Invention, as communicated to me by my foreign correspondent,
consists in constructing screw nuts in such a manner as to remove the liability
of their becoming unscrewed or working loose while in use, as is often the case
with screw nuts of the ordinary kind. For the purpose of preventing this
inconvenience, it has been usual to employ a small screw, which passes through
the side of the nut, and bears against the thread of the screw which carries the
nut; but this mode of securing screw nuts has proved very unsatisfactory, from
the tendency of the small screw to work loose or to fall out and be lost when
the nut is slackened. Now, the present plan dispenses with the lateral
clamping screw, before mentioned, or other loose or free clamping piece, and
in lieu thereof a small clutch lever or tooth cam, mounted in a recess in the
flange of the nut or of the washers of the nut, is employed to take into the
thread of the screw on which the nut is placed, and grip the thread firmly.
In the accompanying Drawing, Fig. 1 shews a cap nut in plan view thus
fitted; Figures 2 shew the inner face of the nut with the washer removed;
Fig. 3 shews the nut in side view as applied to the end of an axle or bolt; and
Fig. 4 shews the nut in cross section. a is the clutch lever, mounted on a
centre pin and chamfered at its inner end to enable it to take into the thread
of the screw of the axletree or bolt, a spring & being employed to press against
the tail of the clutch lever, and keep it in contact with the thread. The
toothed extremity of the lever will, by reason of the excentric form of its profile,
prevent the nut from being turned back until the tooth is withdrawn from the
thread of the screw. The tripping up of the lever clamp (to permit of the

page_text: slackening of the nut) may be effected by passing a pin or stud through the
nut and pressing it upon the tail of the lever; the clamping tooth will then be
raised clear of the thread of the screw bolt or axle, and the nut will be free to
turn. This mode of tripping the lever is shewn at Fig. 5; but a stop piece
permanently connected to the clamp lever, as shewn in the preceding Figures,
and projecting through a slot cut in the side of the nut, may with advantage be
used, the pressure of the finger being in that case sufficient to release the grip
of the clamp. Fig. 5 shews in end view (the moveable cap plate or washer being
removed) an open nut fitted according to this Invention; and Fig. 6 shews
the nut applied to a screw bolt. The clamp, it will be seen, fits into a recess
suitably shaped to permit of its turning, as on a centre pin (which is in this
case dispensed with), and by means of a spring it is pressed forward into close
contact with the thread of the screw. If required, two clamp levers or teeth
may be fitted to the same nut, as shown at Fig. 7, the levers offering a
resistance to the turning of the nut in opposite directions. This arrangement
will be found useful when the nuts are used as stops for adjusting with great
accuracy the reciprocating movement of certain parts of machinery. It is
almost needless to remark, that the screw nuts constructed or fitted as above
described are applicable to all cases where nuts are required to be secured in
any given position.
Having now set forth the nature and object of the Invention of "Improve-
ments in the Construction of Screw Nuts for Axle Boxes and other Purposes,"
as communicated to me by my foreign correspondent, and explained, the
manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim providing screw nuts with
one or more spring catches or trip levers for taking into the thread of the
male screw to which the nut is to be applied, and thereby preventing the
turning of the nut, until the screw is released from the bite of the catch or
trip lever.
In witness whereof, I, the said Frederick Peter Dimpfel, have here-
'unto set my hand and seal, the Twenty-ninth day of September, in
the year of our Lord One thousand eight hundred and fifty-six.
F. P. DIMPFEL. (L.S.)