Apparatus for Indicating or Testing the Alignment of the Shafts of Twin Propellers.
Year: 1890

page_text: Date of Application, 30th June, 1890-Accepted, 2nd Aug., 1890
COMPLETE SPECIFICATION.
Apparatus for Indicating or Testing the Alignment of the Shafts of
Twin Propellers.
I, HORACE KIMBALL JONES, of Hartford, in the county of Hartford, and State of
Connecticut, United States of America, Superintendent of Machinery, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to improvements in detectors for the shafts of twin propellers,
and the object of my improvement is to furnish means for detecting or determining
any sagging or deflection at the screw end of the propeller shafts.
In the accompanying drawings ;-
Figure 1 is a sectional plan view of a portion of a ship's hull, one of the screws
and its shaft with my detector applied thereto, and―
Figure 2 is an end view of said detector together with a vertical section of the
hull, the propeller shaft and its casing.
In propellers having twin screws or wheels, the bearing for the propeller shaft at
the screw end is necessarily in the water outside of the ship's hull and therefore
inaccessible for inspection to determine its condition or for other purpose.
A designates a portion of a hull at the stern of the ship, 3 the bracket on one side
in which is formed the bearing for the shaft 4 of the screw or propeller wheel B,
and 5 is the tube or casing which encircles said shaft. I have shown these parts
only upon one side of the ship, but there will of course be a like screw and its
appurtenances upon the opposite side, and they may be of any ordinary construction.
I arrange in any suitable bearings, a rock-shaft 6 which is preferably enclosed within
the casing 5 and which extends from an accessible part within the ship's hull to the
screw end of the propeller shaft. At the latter point I secure to said rock-shaft an
arm 7 that extends over the shaft for a sufficient length to be brought to bear upon
the top of the same as shown, the rock-shaft being mounted preferably to one side of
a vertical plane passing through the axis of the shaft 4. At the inner end of the
rock-shaft 6 and at an accessible part of the ship I secure the pointer or index 8, the
same preferably pointing in an upward direction. On a suitable bracket or stationary
part which serves as a dial I arrange a stop pin 9 and zero mark 0, the latter being
at a point on the bracket where the pointer or index will stand when it is turned in
a direction to have the short arm 7 of the rock-shaft rest upon the top of the shaft 4
as shown in fig. 2, the shaft being in its normal position. By turning the pointer or
index to the left from the position shown in fig. 2 until it is arrested by the stop 9,
the arm 7 will be withdrawn from contact with the shaft and remain in said position.
It is designed to remain so for the greater part of the time and whenever it is desired
to inspect the shaft, the pointer is turned away from the stop to throw the arm 7 in
contact with the shaft 4. If the pointer or index stands at zero it will indicate that
the shaft is all right in its normal position, but if it falls beyond the zero point, it
will indicate a sagging or deflection of the shaft such as may be caused by wear of
its rear bearing, thereby showing that repairs are necessary. If desired, a series of
graduations or scale of marks in addition to the zero mark may be indicated upon
the bracket or dial. Turning the bearing arm back to remove it from contact with
the shaft prevents wearing of said arm which would otherwise occur.
Having shown and described a simple and efficient device for detecting a sagging
or deflection of the shaft at the part outside of the ship by means of an indicator at
a part accessible within the ship, various modifications and changes therein may
readily suggest themselves to any mechanic, as, for instance, a rod extending at a
right or obtuse angle from the shaft near the screw end to the hull of the ship so that
the end of said rod may be brought in contact with said shaft, and therefore I do not
Price 6d.1

page_text: wish to confine myself to the details of construction herein shown and described,
believing that they may be changed in many ways without departing from the spirit
of my invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim and desire to secure by patent, is-
1. A movable indicator or detector extending from an accessible part of a ship to
that part of the propeller shaft which is near the screw or propeller so that it may be
brought in contact with said part and any material sagging or deflection of said shaft
determined or detected.
2. A detector for propeller shafts consisting of a rock-shaft having an arm at
its outer end for bearing upon the propeller shaft and a pointer or index at its
inner end at a point accessible within the ship, substantially as described and for
the purpose specified.
3. A detector for propeller shafts consisting of a rock-shaft having an arm at
its outer end for bearing upon the propeller shaft, a pointer or index at its inner
end at a point accessible within the ship, and a stop for arresting the reverse
movement of the rock-shaft when turned into a position to remove the detector
arm from the shaft, substantially as described and for the purpose specified.
In witness whereof, I the said Horace Kimball Jones have hereunto set my hand
and seal this Twentieth day of June in the year of our Lord One thousand
eight hundred and ninety.
Witness,
JOHN EDWARDS, Jr.
HORACE KIMBALL JONES.
W. P. Thompson & Boult,
Agents for the Applicant.