AN IMPROVED METHOD OF LOCKING OR SECURELY HOLDING SCREWED NUTS ON THE SCREWED ENDS OF BOLTS, RODS, OR PINS USED IN MECHANICAL AND OTHER STRUCTURES, USED ALSO IN THE CONSTRUCTION OF VARIOUS TOOLS AND IMPLEMENTS
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Benjamin Browne at the Office
of the Commissioners of Patents, with his Petition, on the 23rd
September 1873.
I, BENJAMIN BROWNE, of Stockwell, in the County of Surrey, do
hereby declare the nature of the said Invention for "AN IMPROVED METHOD
OF LOCKING OR SECURELY HOLDING SCREWED NUTS ON THE SCREWED ENDS OF BOLTS,
RODS, OR PINS USED IN MECHANICAL AND OTHER STRUCTURES, USED ALSO IN THE
CONSTRUCTION OF VARIOUS TOOLS AND IMPLEMENTS," to be as follows:-
The object sought to be attained by this Invention is to prevent nuts
from becoming loosened by the vibration or other movement of the
parts to which the pins, bolts, or rods and nuts are connected for holding
such parts together. Take, for example, the caps of plummer blocks
employed to hold the journals of shafting used in machinery, such as a
steam engine shaft. The method commonly employed has been to use
two nuts on each of the screwed pins that hold the journal of the shaft
in the brasses or bearing parts of the plummer block, to prevent the
unscrewing of the said nuts and loosening of the cap of the plummer
block, which in practice takes place by the continued vibration of the
cap during the rotation of the shaft and machinery immediately connected
therewith, and notwithstanding the two nuts are forcibly screwed and
tightened one against the other, the nuts become loosened, and thereby

page_text: fail to hold the cap of the plummer block steady for any considerable
length of time. To obviate this defect various plans have been tried and
patented, but I believe with but partial success.
Now the object of this Invention is to securely lock or hold steady and
immovable such said nuts, which I propose to effect by the following
means:—Instead of forming a continuous right-handed thread or screw
on the end of the bolts or pins of the plummer block, as commonly
practised, I form the screwed part thereof of a compound screw or two
screws, one portion of such screwed part being a right-handed screw or
thread, and the other portion (which is less in diameter) a left-handed:
screw or thread, in other words, the lower half of the entire length of
the aforesaid screwed part. I form with a right-handed screw, and the
upper half I form with a left-handed screw, each fitted with screwed
nuts of corresponding form.
The effect of this arrangement is as follows:-The lowermost or right. :
handed nuts being properly tightened on the cap of the plummer block
and journal of the shaft embraced thereby, the uppermost or left-handed
nuts are then screwed tightly on to the lowermost nuts, so that any
tendency of the lowermost right-handed nuts to unscrew by the vibration
of the machinery would be resisted by the left-handed nuts, which could
only be unscrewed by turning them in an opposite direction to that in
which the right-handed nuts must move to be unscrewed; and it is this
novel and peculiar combination of right and left-handed screws and nuts
which constitutes the feature of novelty in this Invention.
I would here remark that the same effect as the foregoing may be
obtained by screwing a bolt with a left-handed thread into a screwed
hole made in the centre and end of a right-handed screwed pin or bolt,
but I prefer the former method.
It will appear obvious that the above method applies to all kinds of
connections in which screwed bolts, rods, or pins are employed, and
particularly such as are subjected to frequent or continued vibration or
movement.