MENTS IN THRUST BEARINGS FOR SCREW PROPELLOR SHAFTS."
Year: 1880

page_text: LETTERS PATENT to Robert Thompson, of Victoria Chambers, Wigan, in the
County of Lancaster, Consulting Engineer, for an Invention of
MENTS IN THRUST BEARINGS FOR SCREW PROPELLOR SHAFTS."
$5
IMPROVE-
PROVISIONAL SPECIFICATION left by the said Robert Thompson at the Office
of the Commissioners of Patents on the 12th January 1880.
ROBERT THOMPSON, of Victoria Chambers, Wigan, in the County of Lancaster,
Consulting Engineer. "IMPROVEMENTS IN THRUST BEARINGS FOR SCREW PRO-
PELLOR SHAFTS."
The Invention has for its object improvements in thrust bearings for screw
propellor shafts.
In order to lessen the end friction in thrust bearings I employ rolling balls, as
has before been proposed, but my method of constructing the bearing and applying
the balls is novel.
Each set of balls is contained in an open frame, which keeps the balls evenly
spaced and maintains them in any desired position with respect to the centre of the
shaft. The balls are set alternately nearer to and further from the centre of the shaft,
and thus more balls can be got in than there would be room for if they were set
equidistant from the centre of the shaft, and the balls are made to travel round on
more than one path.
The balls abut on one side upon the plane surface of a boss on the shaft, and on
the other side they abut upon a collar through which the shaft passes, and which
collar is adjustable in position to compensate for wear. In order to support the
thrust when the vessel goes astern another similar set of balls is employed on the
other side of the boss on the shaft, and there similarly transmit the thrust to a
collar surrounding the shaft.
These supporting collars can be made of cast iron or steel, with or without
inoveable wearing paths.
The balls can be made of cast iron, either turned or cast in chills, steel, phosphor,
bronze, or of hard brass.
The body of the bearing I make of a cylindrical form with a removeable cap,
and it bodily is adjustable fore and aft on its bed, and is firmly secured by bolts
and nuts, with keys or wedges.

page_text: The cylindrical body is provided with two ends or covers; these enter a short
distance into the body of the thrust bearing, and they carry the collars on which
the rolling balls directly abut. The ends or covers are attached to the body of the
bearing by screws and nuts, and by screwing up more or less the adjustment of the
position of the collars is effected,
For large vessels where the thrust is heavy I provide two or more bosses on
the shaft, one behind the other, and in connection with each I provide a set of
balls to transmit the thrust to a collar upon the end or cover of the bearing, as
described above.
Sometimes I have larger balls towards the outer part of the thrust, and I provide
for these by stepping down the surfaces on which the balls revolve.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Thompson in the Great Seal Patent Office on the 10th July
1880.
ROBERT THOMPSON, of Victoria Chambers, Wigan, in the County of Lancaster,
Consulting Engineer. "IMPROVEMENTS IN THRUST BEARINGS FOR SCREW PRO-
PELLOR SHAFTS."
The Invention has for its object improvements in thrust bearings for screw
propellor shafts.
In order to lessen the end friction in thrust bearings I employ rolling balls, as
has before been proposed, but my method of constructing the bearing and applying
the balls is novel.
Each set of balls is contained in an open frame, which keeps the balls evenly
spaced and maintains them in any desired position with respect to the centre of the
shaft. The balls are set alternately nearer to and further from the centre of the
shaft, and thus more balls can be got in than there would be room for if they were
set equidistant from the centre of the shaft, and the balls are made to travel round
on more than one path.
The balls abut on one side upon the plane surface of a boss on the shaft, and on
the other side they abut upon a collar through which the shaft passes, and which
collar is adjustable in position to compensate for wear.
In order to support the
thrust when the vessel goes astern another similar set of balls is employed on the
other side of the boss on the shaft, and there similarly transmit the thrust to a
collar surrounding the shaft.
These supporting collars can be made of cast iron or steel, with or without
moveable wearing paths.
The balls can be made of cast iron, either turned or cast in chills, steel, phosphor,
bronze, or of hard brass.
The body of the bearing I make of a cylindrical form with a removeable cap,
and it bodily is adjustable fore and aft on its bed, and is firmly secured by bolts
and nuts, with keys or wedges.
The cylindrical body is provided with two ends or covers; these enter a short
distance into the body of the thrust bearing, and. they carry the collars on which
the rolling balls directly abut. The ends or covers are attached to the body of the
bearing by screws and nuts, and by screwing up more or less the adjustinent of the
position of the collars is effected.
For large vessels where the thrust is heavy I provide two or more bosses on the
shaft, one behind the other, and in connection with each I provide a set of balls to
transmit the thrust to a collar upon the end or cover of the bearing, as described
above.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation, partly in section, showing a ring frame containing
a set of balls; a screw shaft is also represented in section in its proper relative
position; Figure 2 is a side elevation, partly in section, of the same parts.
a is the shaft, and a¹ is a boss upon it; the side of this boss bears upon the balls
in the thrust bearing. b, b, are the balls; they are contained in a frame which

page_text: either side, and they have holes in them, smaller in diameter than the balls, but
sufficiently large not to bind upon the balls, and to permit portions of the balls to
project through them on either side. It will be observed that the alternate balls
are set nearer to and further from the centre of the shaft; they are so made to run
upon different tracks.
When thus arranged the balls are less liable to wear
grooves in the supporting face than when the balls all run upon the same circular
track.
Figure 3 shows a vertical section of the bearing with the shaft and two rings of
balls within it. The sets of balls are arranged one on either side of the boss upon
the screw shaft, so that one set of balls supports the thrust when the engines are
turning ahead and the other when going astern. Figure 4 is a plan of this bearing;
and Figure 5 is an end elevation (one half in section) of the same. The body of
the bearing consists of a cylinder d; it is made in two parts, bolted together and
adjustable upon the bed e. When the cylinder d is set it is securely fixed in its
place by bolts and wedges, as the Drawing indicates. The cylinder d is bored out
internally to receive the ends or covers f, f, which fit it accurately. f¹¹, are the
collars on which are the running tracks for the balls; these tracks may be upon
the covers themselves, but it is preferred to have them on collars attached to the
covers, so that they may be more easily renewed when worn. f",f", are wrought
rings which are fixed upon the covers to connect the two halves in which each cover
is made. The covers f,f, are attached by bolts passing through their flanges to the
cylindrical portion d of the bearing, and by these bolts the covers or ends are
adjustable, the bolts being screwed up more or less to set the shaft in position
lengthwise and to compensate for wear.
11
Figures 6, 7, and 8 show a double ball bearing, in which, in order better to take
the thrust when working ahead, two sets of balls supporting two separate bosses
upon the shaft are employed. Figure 6 is a vertical section; Figure 7 is a plan;
and Figure 8 is an end elevation (one half in section). The two rings of balls are,
as the Drawing represents, made of different diameters.
Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I claim as my improvements in
thrust bearings for screw propellor shafts,-
First. The arrangement within the bearing of balls contained in a ring frame,
and set alternately nearer to and further from the centre of the shaft, so that they
travel round upon different paths.
Second. The construction of the bearing with a cylindrical body, having ends or
covers upon which are the collars or running tracks for the balls, such ends or
covers being adjustable to enter more or less far within the cylindrical body as
required.
Third. The construction of a double or compound bearing with two or more
bosses on the shaft, one behind the other, and each supported by a set of balls.
Fourth. My improved thrust bearings for screw propellor shafts, substantially as
described and represented in the annexed Drawings.
In witness whereof, I, the said Robert Thompson, have hereunto set my hand
and seal, this Eighth day of July, in the year of our Lord One thousand
sight hundred and eighty
ROB. THOMPSON. (LS.)