Year: 1886

page_text: We, ARMAND FLAMACHE and EMILE PICARD, both of Brussels in the Kingdom
of Belgium, Engineers, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is an arrangement of nut which cannot work loose
under any circumstances, while its hold or tightening may be increased to any
extent that may be desired, it is founded on the application of differential inclined
planes, both to the nut and its washer.
The nut may be of any desired form, having on its lower surface a flange
constituting a helicoidal inclined plane, terminating in a straight portion, which
forms stop-work with a corresponding portion of the washer. The inclined plane
may have any inclination provided it be different from that given to the thread of
the nut.
The washer plate has on its upper surface, a helicoidal inclined plane of the same
inclination as that of the nut, but in the reverse direction. It terminates like the
latter, in a straight portion of the same height as that of the nut. The washer,
which may be of any desired form, and with four, six, or more sides, or otherwise,
is not threaded on the inside. Under these circumstances it will be readily
conceived that on the washer being placed on the bolt, and the nut being screwed
up, when the nut stop comes in contact with the washer stop, the washer is drawn
round with the nut, until the latter is screwed up as tight as possible. If it be
desired afterwards to unscrew the nut, the washer remains fixed, and as the
inclined plane of the nut slips over the inclined plane of the washer, the hold
of the nut becomes tighter and tighter, since the inclination of the inclined planes
is greater than that of the screw thread. This double inclined plane has, besides,
the advantage of exerting a much greater degree of tightening than in the case of
ordinary nuts. In fact, when the nut is screwed home, if there be a desire to
unscrew it, as the inclined planes have a greater pitch than that of the bolt thread,
the pressure exerted is in inverse ratio to the difference which exists between the
two pitches of the screw, a difference which may be made as small as desired. The
washer is therefore tightened to a greater degree when the nut is unscrewed, and
then on again screwing up the latter, it is again tightened upon the washer.
order to be able, when required, to unscrew such a nut without cutting the bolt, we
reserve the power of cutting the washer with four, six or more sides, or of giving
In

page_text: it such a form that it may be turned at the same time as the nut, by means of a
key or spanner or any other means. It will easily be conceived that, if the washer
turns with the nut, there is nothing to prevent the latter from being unscrewed. It
is evident that the surface of the inclined helicoidal plane may be conical or of any
other suitable form. In applying the same principle of differentially inclined
planes to the tightening of nuts, the tightening may be increased indefinitely by
arranging the inclined planes in a direction opposite to that described above, that
is to say, in the direction of the nut thread, and by giving the washer a pitch
slightly less than that of the bolt thread. Under these conditions in order to
obtain a greater degree of tightening than with ordinary bolt, the nut and the
washer are first tightened together, until the nut is screwed home, after which the
nut is tightened alone. The same inclined plane of the nut, by slipping over
the more slightly inclined plane of the washer, increases the tightening in inverse
ratio to the different inclinations of the inclined planes, and of the nut thread.
Similarly, instead of a simple inclined plane, a screw thread of less pitch than that
of the bolt may be given to the washer, and to the nut, in which case the same
result will be obtained, as that above described.
It is advisable to make the lower face of the washer slightly conical, so as to
have its edges in stronger contact than its inner portion, the washer acting thus as
a spring upon the nut. The hole in the washer should fit exactly the body of
the bolt.
The washer may also be split, and fit the bolt very tight as a spring, and in this
case, the inclined plane of the washer should be slightly conical, corresponding to
the inverse.conical inclined plane of the nut; thus the nut, by being pressed
ágainst the washer, this latter tends to press against the body of the bolt.
:

page_text: We ARMAND FLAMACHE and EMILE PICARD, both of Brussels in the Kingdom of
Belgium, Engineers 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:―
The object of this invention is an arrangement of nut which cannot work loose
under any circumstances whilst its bold or tightening may be increased to any
extent that may be desired. The invention is founded on the application of
differential inclined planes both to the nut and to its washer.
The annexed drawings shew the application of the invention in elevation, in
section, and in perspective. A is a nut of any desired form, having on its lower
surface a flange B constituting a helicoidal inclined plane terminating in a straight_
portion b which forms a stop engaging with a corresponding portion of the washer.
The inclined plane B may have any desired inclination, provided it be different
from that given to the thread of the nut.
The washer A¹ has on its upper surface a belicoidal inclined plane B' of the same
inclination as that of B, but in the reverse direction. It terminates like the latter, in
a straight portion b¹ of the same height as b. The washer, which may be of any desired
form, and with four, six, or more sides or otherwise, is not threaded on the inside.
Under these circumstances, it will be obvious that on the washer being placed on
the bolt, and the nut being screwed up when the stop comes in contact with the
stop b¹ the washer is drawn round with the nut, until the latter is screwed up as tight
as possible. If it be desired afterwards to unscrew the nut, the washer remains
fixed and as the inclined plane B slips over the inclined plane B¹ the hold of the
nut becomes tighter and tighter since the inclination of the inclined planes is
greater than that of the screw thread. This double inclined plane has, besides,
the advantage of exerting a much greater degree of tightening than in the case of
ordinary nuts. In fact if when the nut is screwed home, it be desired to unscrew it,
as the inclined planes have a greater pitch than that of the bolt thread the pressure
exerted is in inverse ratio to the difference which exists between the two pitches
of the screw a difference which may be made as small as desired. The washer is
therefore tightened to a greater degree when the nut is unscrewed, and then on again
screwing up the latter, it is again tightened upon the washer.
In order to be able when required to unscrew such a nut without cutting the
bolt, the washer may have four, six, or more sides, or be of such a form that it can
be turned simultaneously with the nut, by means of a key or spanner or other
means. For the purpose of increasing the adhesion of the washer, its base may be
made slightly concave, say about half a millimetre, so that by the tightening of
the nut, the lower face of the washer bears upon the support forming a spring
against the nut.
In this case as in all the others, it is advisable to make the hole of the washer
exactly the same diameter as that of the bolt to prevent shifting. Another
modification consists in splitting the washer radially and forming the hole slightly
conical, the base of the cone having a diameter equal to that of the bolt, whilst the

page_text: diameter of the top is slightly less causing the washer to grip the bolt. In this
case the lower surface of the washer may be plane or coned as above set forth.
The inclined planes of the washer and of the nut, instead of being straight might
be made conical, the small ends of the cones lying in the direction of the nut. If
desired the lower surface of the washer might be grooved or roughened to increase
the friction. The above modifications are however details of construction merely
and are capable of being varied as circumstances may require, without departing
from the essence of the invention which consists in the application of -differential
helicoidal planes for tightening nuts. In the application of this principle to the
tightening of nuts, it is possible to increase the pressure indefinitely, by arranging
the inclined, planes B and B¹ inversely to the manner above described, that is to
say in the direction of the thread of the screw, and by giving the plane of the
washer an inclination somewhat less than that of the nut. Under these conditions,
in order to obtain a more powerful grip than with an ordinary nut, the user com-
mences by screwing the nut down onto the washer and then by continuing to turn
the nut alone, the inclined planes are pressed together, and the nut in passing over
the flatter inclined plane of the washer, increases the grip in inverse proportion
to the difference of the inclinations of the inclined planes and the thread of the
put. In place of a simple inclined plane there might be arranged in the washer
and in the nut, a screw thread of a less inclination than that of the bolt, and the
same result could be attained thereby.
"Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent I declare that what I claim is :—
· 1. The combination of parts forming a nut and its washer, the contiguous
surfaces of which are cut in helicoidal inclined planes of inclination exceeding that
of the thread of the nut, so as to prevent the latter from becoming unscrewed.
2. The improved. washer placed under the nut and having a helicoidal inclined
plane corresponding to that of the nut, but arranged so that it can be turned by
means of a suitable key, for the purpose of releasing the nut.
3. In screw bolt fittings the nut and washer of which have their contiguous
surfaces arranged in helicoidal inclined planes, either straight or coned, the use of
a radially split washer acting as a clip on the bolt the lower surface of which may
be slightly dished.
4. The herein before described system of bolts and nuts having coned contiguous
surfaces, in place of straight inclined plane surfaces.
5. The combination of parts consisting of a nut and its washer, the latter having
an inclined plane surface of a pitch less than that of the thread of the nut, for the
purpose of augmenting the grip as desired..
6. The replacement of the inclined planes above described and claimed in claim 5
by screw threads.
The whole substantially as and for the purposes described and illustrated in the
accompanying drawings.
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