Improvements in Means for Locking Nuts and Bolts and Set Screws.
Year: 1888

page_text: Date of Application, 3rd Oct., 1888
Complete Specification Left. 2nd Aug., 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Means for Locking Nuts and Bolts and Set
Screws.
I, THOMAS BARNET GRANT of 15 Red Lion Square, Holborn, Middlesex, Electrician
do hereby declare the nature of this invention to be as follows:-
The object of my invention is to provide means by which tapped nuts may be
secured or locked on screwed Bolts and by which screwed Bolts and set screws may be
secured or locked in a tapped nut or hole so that they will not shake loose or become
unscrewed by vibration. This object is effected in the manner and by the means
hereinafter described.
My invention consists in the formation of a washer of suitable thickness made from
steel, iron or other metal or suitable material. The hole in the washer is made the
exact size or a shade smaller than the diameter of the Bolt or Screw with which it
is to be used. One two or more slots are then cut in the washer each slot extending
radially from the inside part way across towards the periphery or outside edge of the
washer. The parts of the washer between the slots and immediately surrounding the
hole are then bent or dished downwards so as to make the hole large enough to allow
the bolt or screw to be easily passed through. A portion of the washer at one or
more points of its outside edge is then turned up in such a manner as to clip one or
more of the flat sides of the nut with which it is to be used.
When the locking
washer thus constructed is placed on the bolt under the nut, the upturned part or
parts clipping the flat side or sides of the nut, the downward pressure of the nut when
being screwed into position will force the dished parts of the locking washer into their
original flat shape thus reducing the hole to its original size and forcing the inside
edges inwards upon the bolt and very tightly gripping the apex of the thread of the
Bolt; and the nut being clipped and held on one or more of its sides by the upturned
edge or edges of the locking washer is prevented froin becoming unscrewed or moving
in any way.
I sometimes jag or form teeth on the inside edge of the washer hole in
order that it may more firmly grip the bolt.
As it is in some cases desirable that the thread of the bolt shall not be marked or
injured in any way I sometimes modify the construction of the locking washers in
order to achieve this end. To effect this I make the hole in the washer in the first
place smaller than the diameter of the Bolt and after cutting slots in the washer
radially part way across to its periphery or outer edge as before described and
enlarging the hole by dishing the parts of the washer between the slots slightly
upwards I screw or tap the hole in the washer (that is to say the inside edges of
the dished parts forming the hole in the washer) with a female thread of the same
pitch as the thread of the Bolt so that it can be easily screwed on to the bolt. One or
more portions of the outside edge of the washer are then bent up on the convex face
of the dished washer the upturned edge or edges being of a sufficient length to clip the
side or sides of the nut when the bottom face of the nut meets the convex face of the
washer. If the locking washer is then screwed on to the Bolt at the same time as
and in conjunction with the nut the downward pressure of the nut as it is screwed
into position forces the locking washer into its original flat shape and the screwed
edges are forced inwards upon the Bolt thus diminishing the size of the hole and
gripping the Bolt in such a manner that the locking washer cannot turn or move and
the nut being clipped on one or more of its sides by the upturned portions of the
locking washer is thus prevented from becoming unscrewed or moving in any way.
I sometimes make the washers without any portion of the edge being turned up to
clip the nut but of a square or oblong shape the inner part of the washer being dished
s herein before described. In this form they are adapted for locking bolts where the
nut is held and the bolt is screwed into the nut such as in fishjoints where each fish-

page_text: plate is grooved on its outside face. In these cases the nut is held in the groove of
one plate and the square or oblong locking washer in the groove of the fellow plate
with the concave face towards the plate. When the bolt is screwed up tightly the
underside of the head flattens out the dished parts of the locking washer the inside
edges being forced inwards upon the bolt, gripping the neck of the bolt in such a
manner that it cannot turn or shake loose; the locking washer being prevented from
turning by the groove in the fishplate.
I can, and sometimes do, enlarge the hole in the washer by dishing the parts
surrounding the hole without cutting radial slots in the washer but 1 prefer cutting the
slots as described as it renders the process of dishing, & enlarging the hole more simple.
. In other cases where it is desirable that there shall be no upturned edge of the
locking washer clipping the side of the nut I make the washer of such a shape as to
correspond with and fit into a cavity or slot formed in the bottom face of the nut with
which it is to be used. When the locking washer is flattened out by the downward
pressure of the nut and securely grips the bolt the nut is firmly held by the outside
edges of the locking washer pressing against the inside edges of the cavity in the
bottom face of the nut and the nut cannot turn or shake loose or I make the locking
washer by cutting four slots partly across the washer radially and dish two opposite
parts downwards and two opposite parts upwards-the opposite parts which are
dished downwards being longer than the parts dished upwards. A projection or boss
in the cavity formed in the bottom face of the nut immediately surrounding the hole
and of the same thickness as the metal of which the locking washer is made is gripped
by the inside edges of the parts of the locking washer which are dished upwards and
the bolt is gripped by the inside edges of the longer or downward dished parts of the
locking washer in consequence of the downward pressure of the nut flattening out the
dished parts of the locking washer and reducing the size of the apperture.
The washer as hereinbefore described is also adapted to lock set screws a portion of
the outside edge of the washer being turned up or down so as to clip over the edge of
the plate or work into which the screw is put or the corners or edges of the washers
can be pressed or bent into any cavities or grooves in the work which may exist or be
made for the purpose.
Dated this Rest day of October 1000
COMPLETE SPECIFICATION.
Improvements in Means for Locking Nuts and Bolts and Set
Screws.
I, THOMAS BARNET GRANT, of 15 Red Lion Square, Holborn, Middlesex, Electrician,
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 my invention is to provide means by which nuts may be secured or
locked on bolts and by which screws may be secured or locked in a nut or tapped hole
so that they will not shake loose or become unscrewed by vibration.
For the purpose of locking a nut I employ a dished washer having a central hole
and several cuts extending from the hole towards the circumference so as to divide the
washer partially into segments each capable of flexure. The outer edge of the
washer is partly or wholly turned up so as to present a lip or lips embracing the side
or sides of the nut or the washer may be square or polygonal engaged in a recess of
the nut. When the nut is screwed home with the dished washer under it the washer
is flattened its segments being bent back towards a plane parallel to the base of the
nut so that they are made to grip the bolt so firmly as to be incapable of turning when
subject to vibration. The nut itself being prevented by the washer from turning is
thus locked on the bolt.
The washer may have some of its segments turned down to grasp the bolt as above
described and some segments turned up to grasp a boss of the nut.

page_text: For the purpose of locking a screw I place a similar dished washer under the head
of the screw this washer being engaged in a recess or groove. On screwing the screw
home, the washer is flattened and made to grip firmly the neck of the screw.
Fig. 1 of the accompanying drawings is an edge view and Fig. 2 is a plan of one
form of washer according to my invention. Fig. 3 shews it in section under a nut
before the nut is screwed down and Fig. 4 shews it when the nut is screwed home.
In this case the central hole of the washer is of such diameter that when the washer
is flattened, it will grip the bolt firmly, being thus prevented from turning, and the
nut held botween the upturned lips of the washer is itself prevented from turning.
Figs. 5, 6, 7 and 8 are corresponding views shewing a washer the hole of which is
threaded after the washer is dished. Fig. 9 shews a dished washer of square or
polygonal form engaged in a recess of the nut. Fig. 10 shews a square or polygonal
dished washer engaged in a recess or groove under a screw head. Fig. 11 is an edge
view and Fig. 12 is a plan of a washer with two of its segments dished upwards and
two dished downwards. Fig. 13 shews this washer in position under a nut. On
screwing the nut home the one pair of segments are made to grip the bolt and the
other pair to grip a boss formed on the underside of the nut. Obviously, the shapes
of the washers and of the cuts forming their segnients may be varied, and the washers
may be of various materials, preferably in most cases of steel with sufficient elasticity
to resume their dished form when they are released. The inner edges of the segments
may be serrated or jagged if desired to take a firmer hold of the bolt.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described method of locking a nut or screw by the flattening of the
bent segments of a dished washer placed under the nut or screw head and engaged
with the nut or in a recess in such manner that the washer in being flattened is made
to grip the bolt or screw and the nut or screw head is thus prevented from being
turned by vibration.
2. For the purpose of locking a nut on a bolt, the combination with the nut
and bolt of a dished segmental washer, substantially as described with reference to
Figs. 1 to 9 inclusive of the accompanying drawings.
3. For the purpose of locking a screw, the combination with the screw head of
a dished segmental washer engaged in a recess or groove substantially as described
with reference to Fig. 10.
4. In combination with a bolt and with a bossed nut a washer having segments
dished in both directions, substantially as described with reference to Figs. 11, 12
and 13.
Datad this 2nd dor of August 1889
ABEL & IMRAY,
Agents for the Applicant.