An Improved Nut and Washer Combination for Screwbolts.
Year: 1896

page_text: Date of Application, 3rd Feb., 1896-Accepted, 26th Sept., 1896
COMPLETE SPECIFICATION.
An Improved Nut and Washer Combination for Screwbolts.
I, JEREMIAH BERNARD GUNNING of No. 2 Castlereagh Street, Sydney in the
Colony of New South Wales, Jeweller, do hereby declare the nature of my
invention, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The invention consists of certain improvements in nuts and washers for screw
bolts which has been devised to prevent the latter from ever giving way or becoming
loose through jolting, friction, vibration, change of temperature, etc., and at the
same time to secure the necessary firmness and strength for the various purposes
for which screw bolts are used.
The essential features of my invention lie in using a cup shaped washer of steel
or any suitable metal with one or a number of indentations and sharp projections
of the nature of ratchet-teeth on the concave side, against which, the nut, which
may be of any metal is to be screwed, the nut also has one or several such projec-
tions or teeth corresponding to the washer and fitting close when screwed
together. The elasticity of the concave side of the washer facing the nut will
cause the tooth or teeth of the nut in screwing to suap past the tooth or teeth
of the washer till the necessary firmness is obtained. The washer is prevented
from turning by having the hole in the centre not perfectly round but a segment or
projection left fitting to a flat surface or groove on the bolt, or by a protuberance
or several of them on the convex side of the washer fitting into an indentation or
cavity on the object against which the washer is placed, both devices if necessary
may be used together as well as singly. No amount of jolting, friction, vibration,
change of temperature etc., will cause the bolt to unscrew or disturb the junction of
the washer and nut. The nut can be unfastened by insertion of a wedge between
the nut and washer until the nut has been screwed out of the range of the elasticity
of the washer. Bolt, nut and washer may be used again.
In order that my invention may be more clearly understood I will now proceed
to describe the drawings hereto attached, in which like letters of reference denote
similar parts in each figure.
Fig. 1 is an elevation of a bolt fitted with my improved nut and washer
combination.
Fig. 2 is an elevation shewing the nut and washer in section.
Fig. 3 is a plan, and Fig. 4 shews a plan of the washer illustrating one method
I use to prevent the washer from turning on the bolt.
In each of the figures A, is a bolt with a flat B, formed on the thread to receive
a concave or cup shaped washer C which is provided with one or more ratchet
teeth b, on its concave side, which engage with one or more teeth or projections a,
(Fig. 2.) formed on the nut D. When the nut D is tightened up the elasticity of
the washer C, allows the tooth or teeth a, on the nut D to snap past the ratchet
tooth or teeth b, until the required tension on the bolt is obtained.
c, Fig. 1 shews the combination of the toothed nut D. with the ratchet toothed
washer C, when the nut is finally screwed up.

page_text: Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The tooth, teeth or protuberances on nut D marked a, the tooth or teeth on
washer marked b, and the combination of the two marked c, as per drawing
enclosed.
Dated this 30th day of December 1895.
JEREMIAH BERNARD GUNNING.