IMPROVEMENTS IN APPARATUS FOR REMOVING SCREW PROPELLERS FROM THEIR SHAFTS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 9th April 1883. Com-
municated to him from Hippolyte Emmanuel Gouget and Antoine Didier
Emile Vincent both residing at Paris in the Republic of France
$
"
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields, in the County of Middlesex,
Gentleman IMPROVEMENTS IN APPARATUS FOR REMOVING SCREW PROPELLERS
FROM THEIR SHAFTS a communication to me by Hippolyte Emmanuel Gouget
and Antoine Didier Emile Vincent both residing at Paris in the Republic of
France
This Invention relates to improved apparatus for removing screw Propellers from
their shafts as hereinafter described.
The operation of removing Screw Propellers from their Shafts as heretofore
performed is attended with serious difficulties and disadvantages. The removal is
generally effected by taking off the nut from the end of the shaft and striking
heavy blows with a sledge hammer or other like powerful instrument upon the
boss or hub of the Screw or propeller or upon wedges suitably arranged-This
tedious and costly operation frequently fails to produce the desired effect in this
case the hub is heated and the shaft cooled and the hammering is then repeated
This latter method also often proves unsuccessful and it then becomes necessary to
resort to the undesirable expedients of either cutting the shaft in front of the boss
of the propeller or breaking up the latter
The object of the present Invention is to provide a remedy for these disadvantages
by means of an apparatus hereinafter described which enables the Propellers to be
separated from their shafts with certainty and dispatch.
This apparatus is composed of a strong cross bar provided with means for
connecting it to a suitable lifting apparatus employed for placing it in position—A
hole is formed in this cross bar near each extremity for the reception of two
hooked tension bars terminating at one extremity in a screw engaging with a nut
In order to pull off the screw or propeller the cross bar is introduced into the
Propeller frame and caused to bear at its centre upon the extremity of the propeller
shaft from which the nut has been previously removed. The cross bar being
supported in this position the hooks of the tension bars are caused to engage with
the two opposite blades of the propeller the said bars being adjusted to the required

page_text: length by means of the nuts on their extremities-This being done the said nuts
are turned so as to exert a powerful drawing action upon the propeller which is
thus soon started and readily slides off the shaft
By means of this arrangement the whole of the strain is taken by the propeller
and its shaft and no force is applied to the Stern post.
The pitch of the drawing off screw on the tension bars is preferably less than
that of the tightening Screw on the propeller shaft but any other desired proportion
between the threads may be employed The tension bars in place of terminating in
hooks may be provided with any other suitable device to enable them to lay
hold of the blades or hub of the propeller The arrangements hereinbefore
described are equally applicable to either four or two bladed propellers-In the
case of three bladed propellers one of the tension bars is hooked on to one of the
blades and the hook of the other tension bar is caused to engage with a bar laid
across the two blades on the other side of the Propeller.