Improved Means for Locking Nuts and Bolts.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improved Means for Locking Nuts and Bolts.
I HERMAN LÖHNERT of Bromberg, Prussia, Manufacturer do hereby declare
the nature of my said invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
This invention has for object certain novel means for preventing nuts from working
loose on their bolts from vibration and other causes each bolt and nut being
locked by a strip of soft metal, as a key or cottar, capable of being torn asunder
on the application of excessive power.
The invention is clearly exemplified by the annexed drawings.
Figure 1 is a side elevation of bolt and nut.
Figures 2. 3 and 4 are end views of the bolt with two grooves or slots and of the
nut with three grooves or slots.
Figure 5 is a detached view of the key or cottar.
Figure 6 represents the strip of soft metal which has been torn in two pieces such
as when the nut has been forcibly turned to loosen it.
The bolt B is provided with grooves c and the nut A with grooves d. When
tightening or screwing up the bolt and nut the grooves c and d. meet together and
form a common channel c, d, into which is inserted a pin or cottar 9 of corresponding
form (Figure 5) and of suitable material which thoroughly prevents the nut from
becoming loosened.
It is impossible to remove the pin or cottar g from the channel c, d, by an outward
pull or a push from inside.
When the nut requires to be loosened the same is turned forward or backward
with force by the aid of a spanner and the pin or cottar is cut or severed against the
sharp edges of the screw thread and upon the whole of its length into two parts h
and (Figure 6) one of which fills up the groove c while the other fills the
groove d. A subsequent loosening or tightening of the nut is thereby in no wise
prevented.
According to requirements the number of grooves such as c and d can be
increased or decreased in order to obtain a greater number of locking parts acting at
a single turn of the nut. In the example illustrated in the drawing it is carried out
by means of three grooves d (Figure 3) formed in the nut A and of two grooves c
(Figure 4) formed in the bolt B in order to effect the locking at a 6th part of a
revolution. In this arrangement it is possible to tighten once and obtain a renewed
locking of the screw by using the still empty groove in the bolt without having to
unscrew the nut and to remove, as would be otherwise required, the cut halves h, i of
the pin or cottar from the grooves c and d.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
As a means for locking screw bolts and nuts, the employment of pins or cottars of
softer material in corresponding grooves formed in both the bolt and nut, in such a
manner that the screw thread can only become released or loosened when the inserted
pin or cottar is cut lengthwise by turning the nut with force.
Dated this 26th day of November 1889.
H. GARDNER,
166, Fleet Street, London, Agent for the said H. Löhnert.