Year: 1888

page_text: We, FREDERICK PURBRICK of Shirley Grove, East St. Kilda near Melbourne in
the Colony of Victoria, Architect and Engineer and ROBERT HOLDEN STONE of North
Brighton near Melbourne aforesaid, Civil Engineer do hereby declare the nature of
this invention and in what manner the same is to bo performed, to be particularly
described and ascertained in and by the following statement :-
This invention has been devised for the purpose of providing means for locking
nuts or bolts which shall not involve any great expense in the manufacture, which
shall be simple and effective in operation, and which can be unlocked without any
great trouble.
It consists of a special construction of nut and a special construction of washer,
while the bolt upon which said contrivances are to be used must have some means
for preventing the rotation of the washer, such, for instance, as a flat or a groove on
one side of the bolt.
Our improvement in the nut consists in making an otherwise ordinarily shaped nut
with serrations or ratchet teeth on its inner or forward face.
Our improved washer consists in making it so as to fit but not to revolve on the
bolt to which it is to be applied, that is to say, the hole for the passago of the bolt is
not made perfectly circular, but is made to correspond with the bolt itself, so that if
the bolt have a flat on one of its sides so also will the washer.
This washer also has another peculiarity inasmuch as it has a projecting dog or
pawl formed by a strip of the washer, which dog or pawl when required gears into
the ratchet teeth on the inner face of the nut so as to prevent its rotation in the
direction of unscrewing whilst allowing the nut perfect freedom to be screwed up.
When the nut is required to be unlocked, the dog or pawl must be removed out of
gear with the ratchet either by a wedge or a lever or by tearing or breaking it off.
Referring to our Drawings,-
Figures 1 and 2 are a plan and a side elevation respectively of our improved nut.
Figures 3 and 4 shew respectively a plan and side view of our improved washer.
Figure 5 shows a bolt having a flat on one of its sides to which our nut and
washer are applied.
Figure 6 is a plan of the underside of the contrivance shewn in Figure 5.

page_text: Figures 7 and 8 are a plan of a washer and a plan of the inner face of a nut
respectively constructed according to a modification of our invention, and
Figure 9 is a longitudinal section illustrating the application of the washer and nut
shewn in Figures 7 and 8 respectively.
Figures 10 and 11 are plan and side elevation respectively of a washer constructod
according to a further modification of our invention.
The ratchet toeth on the inner or forward face of the nut are marked A and the
flat side of the hole through which the bolt passes is marked B whilst the outer strip
forming the dog or pawl is markod D and has its extremity bent where it is marked Di
so that it will engage with the teeth A on the nut.
In Figure 5, our improved nut and washer are shown in position on a bolt to
which they are to be applied from which it will be seen that the nut can be turned
from left to right in the direction shown by the arrow without receiving any hindranco
from the washer but that the dog or pawl D prevents the unscrewing of said nut by
catching in the ratchet teeth, as clearly shewn, so that it can only be removed either
by depressing said dog or pawl by means of a wedge or lever, or by forcibly tearing
or breaking it off.
In the modification of our invention illustrated in Figures 8, 9 and 10, tho ratchet
teeth do not extend across the face of the nut, as in the previous figures, and, in
addition to this, slots E E are cut as shown from the outer to the inner side thereof,
to allow a wedge or lover to be inserted therein in order to remove the dog or pawl'
from engagement with the teeth on the nut so that it may readily be removed as
herein before mentioned.
We would have it understood that although in our drawings we have only illustrated
around washer, yet it is obvious that it might be square, hexagonal or any
other shape.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is:
First. Our improved nut having ratchet-teeth cut on its inner or forward face,
substantially as herein described and as shewn in Figures 1, 2 and 8 of our
drawings.
Secon. Our improved washer provided with a flat such as B, or other equivalent
means to prevent its rotation on the bolt and having a dog or pawl D cut preferably
from one portion of its edge substantially as heroin described and as shewn in
Figures 3, 4, 7, 9 and 10 of our drawings.
Third. The combination of our improved nut with our improved washer on a bolt
having a flat on one side, or other equivalent means of preventing the rotation
of the washer substantially as herein described and as shewn in Figure 5 of our
drawings.
Dated this Nineteenth day of September One thousand eight hundred and
FREDERICK PURBRICK.
ROBERT HOLDEN STONE.
Wm. P. Thompson. &. Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicants.