IMPROVEMENTS IN BUSH KEYS OR TOOLS FOR FIXING OR REMOVING SCREW BUSHES SUCH AS ARE APPLIED TO CASKS
Year: 1876

page_text: LETTERS PATENT to John Dunbar, of Glasgow, in the County of Lanark,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN BUSH KEYS
OR TOOLS FOR FIXING OR REMOVING SCREW BUSHES SUCH AS ARE APPLIED TO
CASKS."
Sealed the 11th August 1876, and dated the 16th February 1876.
PROVISIONAL SPECIFICATION left by the said John Dunbar at the Office
of the Commissioners of Patents on the 16th February 1876.
JOHN DUNBAR, of Glasgow, in the County of Lanark, North Britain, Engineer.
IMPROVEMENTS IN BUSH KEYS OR TOOLS FOR FIXING OR REMOVING SCREW
BUSHES SUCH AS ARE APPLIED TO CASKS."
This Invention has for its object the constructing of bush keys or tools used for
fixing or removing the screwed metallic bushes which are now commonly applied
to strengthen and protect the bung holes of casks so that they may be fixed to the
bushes by the application of less force than heretofore, and so that by acting on
several points they may not distort or injure the bushes.
The improved bush keys are convenient in use and not liable to be broken or
otherwise deranged by the strain that has to be applied.
A bush key made with one modification of the improvements comprises a central
mandril, the outer end of which is squared to receive a lever or handle for turning
it by. Near its inner end also the mandril is made square but with the corners
rounded, and to this squared part there are applied four segments, the outsides of
which combine to form a tapered or nearly cylindrical surface, that is, fluted or
grooved longitudinally. These grooved segments fit between a collar on the mandril
and a screw nut or second collar, and they are held in place on the mandril by a
strong ring of vulcanised rubber which is sprung into a groove formed round the
set of segments.
The tool when being used is thrust firmly into the bush, and then on a turning
strain being applied to the mandril the corners of the squared parts acting on the
insides of the several grooved segments tend to thrust them outwards so that they
bear on four different parts of the inside of the bush and cause it to turn with very
little strain.

page_text: The tool may be made with three or other convenient number of grooved
segments instead of four, the part of the mandril acting on the segments being made
with a corresponding number of sides; or the square mandril may have two semi-
circular segments applied to it instead of four.
The grooved segments are by preference made of steel and the mandril of
wrought iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said John Dunbar in the Great Seal Patent Office on the 12th August 1876.
JOHN DUNBAR, of Glasgow, in the County of Lanark, North Britain, Engineer.
"IMPROVEMENTS IN BUSH KEYS OR TOOLS FOR FIXING OR REMOVING SCREW
BUSHES SUCH AS ARE APPLIED TO CASKS."
My said Invention has for its object the constructing of bush keys or tools used
for fixing or removing the screwed metallic bushes which are now commonly applied
to strengthen and protect the bung holes of casks so that they may be fixed to the
bushes by the application of less force than heretofore, and so that by acting on
several points they may not distort or injure the bushes.
The improved bush keys are convenient in use and not liable to be broken or
otherwise deranged by the strain that has to be applied.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append a Sheet of explanatory Drawings
to be herein-after referred to and representing one modification of my improved
bush keys. In these Drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
Figure 1 of the Drawings is a transverse vertical section, Figure 2 is a side
elevation, and Figure 3 is an end elevation of a bush key made with one modifica-
tion of my improvements.
The tool comprises a central mandril 4 having its outer end 5 squared to receive
a lever or handle for turning it by; near its inner end 6 also the mandril is made
square but with the corners 7 rounded, and to this squared part there are applied
two semicircular segments 8, the outsides of which combine to form a tapered or
nearly cylindrical surface that is fluted or grooved longitudinally; these grooved
segments 8 fit between a collar or shoulders 9 on the mandril 4 and a screw nut 10
or a second collar, and they are held in place on the mandril by a strong ring 11 of
vulcanised rubber, which is sprung into a groove formed round the segments 8.
The tool when being used is thrust firmly into the bush (no percussive action
being required), and then on a turning strain being applied to the mandril 4 the
corners 7 of the squared part 6 (shown in section in Figure 1) acting on the insides
of the grooved segments 8 tend to thrust them outwards so that they bear on
different parts of the inside of the bush and cause it to turn with very little strain.
The shoulders 9 are made segmental, and the grooved segments 8 are formed with
segmental parts 12 entering between the shoulders and limiting the extent to which
the mandril 4 can be turned relatively to the grooved segments 8.
The tool may be made with three or other convenient number of grooved
segments (8) instead of two, the part of the mandril acting on the segments being
generally made with a corresponding number of sides.
The grooved segments are by preference made of steel, and the mandril of
wrought iron.
Having thus particularly described my said Invention, and the manner of per-
forming the same, I have to state that I do not restrict myself to the precise details
herein described or delineated, but that what I believe to be novel and original and
claim as the Invention secured to me by the herein-before in part recited Letters
Patent is, the combination of the round cornered, square, or polygonal part 6 of the

page_text: mandril 4 with two or more externally grooved or fluted segments 8, substantially
as and for the purposes herein-before described.
In witness whereof, I, the said John Dunbar, have hereunto set my hand
and seal, this Ninth day of August, in the year of our Lord One thousand
eight hundred and seventy-six.
JOHN DUNBAR. (L.S.)