IMPROVEMENTS IN SCREW BOLTS AND NUTS AND IN WASHERS THEREFOR "
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Thomas Hancock at the Office of
the Commissioners of Patents on the 18th November 1882.
THOMAS HANCOCK, draughtsman in the employment of Messieurs Bayliss, Jones
and Bayliss of Wolverhampton in the County of Stafford, bolt, nut and fencing
manufacturers, "IMPROVEMENTS IN SCREW BOLTS AND NUTS AND IN WASHERS
THEREFOR
"
The object of this invention is to provide simple and efficient means whereby
the single nut ordinarily used at one end of a screw bolt (or each nut when a
single nut is employed at each end) may be prevented from working loose upon its
bolt.
According to one modification of this invention the nut is constructed in the
ordinary manner, except that the corner formed at the inner face, by the inter-
section therewith of the hole through the nut, is slanted or bevilled off thus
forming a conical recess round the hole sufficient to admit of the washer, next to be
described, entering somewhat therein. The washer is formed out of a sufficient
length of wire or rod (preferably of steel) by bending the said length of wire or
rod into a circular form with an inner diameter just sufficient to allow of passing
over the bolt. The two ends of the length of bent wire or rod are some distance
apart from meeting one another before the nut is screwed up, and one of such ends
is bent slightly inwards and the other slightly outwards, the latter with an angle
of inclination upwards also of say 45°, and each is formed with a sharp corner or
edge, the former on its inward side and the latter on its outward and upward side.
A part of the coil forming the washer is looped up somewhat from the plane of the
coil and near to the end thereof having the outward turn. When the nut is
screwed up against the wasber, the outer face of the looped up part enters the
recessed part in the inner face of the nut, and as the nut is further screwed up the
looped up part of the washer is compressed by the conical recess in the nut, thus
lengthening the coil circumferentially and raising the end adjacent to the loop and
pressing the sharp corner or edge thereof into the body of the nut. The sharp
corner or edge at the other end of the coil is forced into the screwed part of the
bolt as the nut is screwed down, and the coil thus locks or fixes the nut on the
thread of the bolt rendering it impossible when the nut is screwed up for it to
D

page_text: work loose by any extent of vibration. The pressure of the nut upon the looped-up
part, aforesaid, throws a continual strain upon the washer circumferentially, tending
thereby to turn the nut in a screwed up direction. When the nut is screwed up
tightly the outer face of the washer is somewhat within the recessed part in the
inner face of the nut.
An ordinary washer may, if desired, be used in addition to the washer above
described.
According to another modification of this invention a slit is formed down the
centre of the bolt from the end thereof and for the distance along which the bolt
is screwed. A sliding-piece, of a thickness to slide readily down the slit, is formed
of a width not exceeding the diameter of the bolt at the base of the screw thereon,
but has an ear formed out at each side thereof at one end, projecting somewhat
beyond the bolt, and has the other end gradually thickened up for a short distance
to slightly more than the width of the slit, the thickened part thereof being at the
extreme end of the sliding-piece. The washer is formed with niches in its inner
face to fit over the ears of the sliding-piece. In fixing the bolt, the end of the
sliding-piece having the ears thereon is entered down the slit within the bolt, the
thickened or wedge-shaped part of the said sliding piece being left projecting
beyond the end of the bolt. The washer is then put on over the said ears and the
nut is run on and as it is screwed up carries with it the washer, and, consequently
therefor, the sliding-piece, and draws the thickened or wedge-shaped part within
the slit of the bolt, thus opening out the bolt slightly at the back of the nut as the
latter is screwed up. The outer end of the sliding-piece is of course thickened up
very slightly only, and extends out entirely beyond the outer face of the nut. It
will be obvious that the slight wedging out of the parts of the bolt on either side of
the slit will securely prevent the nut from unscrewing. Instead of forming niches
in the inner face of the washer, an annular rebate may be formed on the inner face
of the nut, of a radial section to correspond with the contour of the ears of the
sliding-piece which are then within the nut as the same is screwed up. The ears
are preferably made with their sides slanting out from the sliding-piece. The niches
aforesaid may, if desired, be formed through the washer and the ears formed with
shoulders upon which the face of the nut then bears direct.
.
This invention is specially useful in the case of railway bolts, but may of course
be employed for other purposes where bolts are subject to vibration, or where it is
required that the nuts shall be thoroughly secure.