IMPROVEMENTS IN THE MEANS OF LOCKING OR SECURING NUTS ON BOLTS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Stephen Watkins at the Office of the
Commissioners of Patents on the 30th November 1882.
STEPHEN WATKINS of Wolverhampton in the County of Stafford, Consulting
Engineer 'IMPROVEMENTS IN THE MEANS OF LOCKING OR SECURING NUTS ON
BOLTS
“
The object of this invention is to construct bolts and nuts in such a manner
that the nut may be readily screwed up on the bolt but be securely prevented from
coming unscrewed, or shaking loose therefrom accidentally under vibration or from
other cause.
A groove is formed down the screwed part of the bolt and of such length and in
such position thereon as may be necessary for the circumstances in which it is
desired to use the bolt. A flat or other conveniently shaped spring is placed in the
groove, which latter is deep enough to allow the spring to be below the base of the
Grooves are formed
screw thread on the bolt when the spring is pressed down.
across the thread of the nut in such a way as to leave a shoulder along one side of
each groove and an inclined plane on the other side of each groove, the inclined
plane running in cross section from the base of the shoulder up to the top of the
threads. The shoulders face backwards from the direction in which the nut is
screwed up. Before running the nut down upon the bolt to screw it up, the spring
aforesaid is placed within the groove in the bolt with its inner end abutting
against the inner end of the groove, the spring then rising or bowing up between
its two ends above the base of the threads upon the bolt. As the nut is screwed
up over the spring the latter is pressed down by the thread of the nut into the
groove in the bolt. During the screwing up of the nut part of the spring rises
somewhat out of the groove in the bolt as each of the grooves in the nut passes
over it but is again depressed by the corresponding inclined planes. The nut is
prevented from coming unscrewed or shaking loose on account of the spring
catching against one of the shoulders, aforesaid, as the nut turns backwards. It is
preferred to form the groove in the bolt somewhat inclined in cross section so that
the flat or outer face of the spring may incline in the same direction as the inclined
planes aforesaid and thus facilitate the running on of the nut. The spring may of
course be carried in a groove in the nut if desired and grooves formed across the

page_text: threads of the bolt to work in conjunction therewith, in which case the shoulders
on the bolt face in the direction in which the nut is screwed up.
The invention as above described may be modified by forming a groove in a
direction around the bolt and placing a spring therein having a tendency to rise
up at one end and engage with the shoulders in the nut, the said spring being held
from turning round with the nut by having its back end turned down into a recess
in the groove or otherwise fixed; or a recess may be formed down into the body of
the bolt and a spiral spring or other elastic equivalent be inserted therein the said
spiral spring or equivalent having its outer extremity suitably shaped or capped to
engage with the shoulders in the nut.