Improved Thrust Bearing.
Year: 1894

page_text: Date of Application, 15th Feb., 1894
Complete Specification Left, 14th Nov., 1894-Accepted, 15th Dec.,. 1894
PROVISIONAL SPECIFICATION.
Improved Thrust Bearing.
We, ARCHIBALD SHARP, of. 13 Fairlawn Grove, Chiswick, London, Engineer,
and WILLIAM CARLILE WALLACE, Glenhuntley, Port Glasgow, Engineer, do.
hereby declare the nature of this invention to be as follows:-
This invention relates to an improved thrust bearing for shafts of engines, and
the object is to provide a thrust bearing which shall be less frictional and absorb
less power than those hitherto in use.
In carrying out our invention we provide a number of conical hardened steel
rollers which run between a conical hardened steel surface on the shaft and a
conical hardened steel surface on the fixed part of the bearing. The pressure
being normal to the surface of contact between the roller and the shaft there is a
considerable thrust of the conical rollers outwards. This is taken up by adjustable
set screws mounted in a live ring which revolves at half the speed of the shaft.
If the roller had direct contact with its set screw the relative speed would be so
great that abrasion would soon take place. To provide against this we introduce a
number of lens-shaped hard steel discs between the roller end and its set screw, so
that the relative motion may be divided. In our thrust block we have a provision
for letting the oil in between the steel discs periodically.
The shaft should be supported in a plain cylindrical bearing co-axial with the
fixed conical path.
Dated this 14th day of February 1894.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.
COMPLETE SPECIFICATION.
Improved Thrust Bearing.
We. ARCHIBALD SHARP, of 13 Fairlawn Grove, Chiswick, London, Engineer,
and WILLIAM CARLILE WALLACE, Glenbuntley, Port Glasgow, Engineer, 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:-
Our invention relates to an improved thrust bearing for shafts of engines,
turbines, and generally for any other rotating shaft subjected to end thrust; and
the object is to provide a thrust bearing which will be less frictional, and absorb
less power than those hitherto in use.
In carrying out our improvements we provide a number of conical hard steel
rollers, which run between a conical hardened steel surface on the shaft and a
conical hardened steel surface on the fixed part of the bearing. The pressure
being normal to the surfaces of contact between the roller and the shaft and
between the roller and the fixed bearing, there is a considerable thrust in the
conical rollers outwards. This is taken up by adjustable set screws, mounted in a
live ring which carries the rollers and revolves at half the speed of the shaft. If
the roller had direct contact with its set screw, the relative speed would be
generally so great that. abrasion would soon take place. To provide against this,
we introduce a number of flat or lens-shaped hard steel discs between the roller

page_text: and its set screw, so that the relative motion may be divided. In our thrust
block we have a provision for letting the oil in between the steel discs
periodically.
The shaft should be supported in a plain cylindrical bearing co-axial with the
fixed conical path.
In order that our invention may be properly understood and readily carried
into effect we have hereunto appended two explanatory sheets of drawings in the
several figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 is a longitudinal section of our improved thrust bearing as applicable
to the shafting of screw steamers, or to any shaft in which the direction of the
thrust may be reversed.
Figure 2 is a part end view and part transverse section of the same.
Figure 3 is a detached view, drawn to an enlarged scale, of some of the working
parts hereafter more fully described.
In Figure 1, a a represent the conical rollers, formed preferably of hard steel.
These conical rollers a a are carried in a live ring h, which is provided with
openings formed in the cheeks of the ring and through which the conical
surfaces of the rollers a a protrude, as seen more particularly in Figure 2. In the
particular arrangement shown in Figures 1 and 2 each live ring bis split into two
by the plane in which the axes of the conical rollers lie; the two parts being held
together by bolts. Each half ring is again split along a diameter, so that the ring
may be placed in position without disturbing the shaft couplings. A conical
projection d (tapering outwards) formed on the shaft d transmits the thrust,
through one ring of conical rollers to the fixed part of the bearing E.
If the
thrust be reversed in direction, it will be transmitted through the other ring of
rollers to the other end of the fixed bearing. The roller paths on the shaft
projection d and on the fixed bearing E are formed by rings e, preferably of
hardened steel.
In order to take up the considerable thrust of the conical rollers a a, imparted
outwards as hereinbefore described, each conical roller a is provided with an
adjustable set screw f mounted in the said live ring b. On each conical roller a
are formed two short extensions or shanks a', which rest in plain bearings on the
live ring b. Between the end of the outer shank and the set screw fa number of
flat or lens-shaped discs g are inserted, so that the relative motion is divided and
abrasion obviated; the said set screw and discs g being more particularly shown in
elevation and plan at Figure 3.
A method of lubricating and thus preventing any undue friction is illustrated
in the lower half of Figure 1 by the dotted lines h h. Oil is fed into the recess
or recesses ii of the bearing E by the holes jj, from which it freely circulates to
the working parts. If the upper part of the hardened steel roller path e on the
fixed part of the bearing E be slightly hollowed, each roller as it passes its
topmost position in each revolution will drop slightly and the discs will separate,
thus allowing the oil, which might otherwise be squeezed out, to get periodically
between the surfaces of contact of the discs g.
g
In the particular form of thrust bearing illustrated by Figures 1 and 2, should a
roller break, one part of the fixed bearing will have to be moved, and the halves
of the live ring separated before a new roller can be inserted. Figure 4 shows a
modification of the live ring, whereby a broken roller can be replaced without
tisturbing any other part of the mechanism. The live ring b in this case is in
ne piece, or only jointed diametrally for the purpose of putting it in place without
disturbing the shaft couplings. The outer shank a¹ of each roller a, the set
serewf, and discs are carried by a cover k fastened to the live ring by two bolts
r studs 1.
Though the axes of the conical rollers are shown at right angles to the axis
f the shaft in Figure 1, we do not limit ourselves to this arrangement; for
example, it might be advantageous, in some cases, to have one of the roller paths e

page_text: a flat disc. In any case, the vertices of the conical rollers and of the roller paths
should all coincide at v.
Again, though the arrangement of conical roller shown in Figures 1, 2, and 4
is perhaps the most generally convenient, a double conical roller (Figure 5) may
le used. If the smaller cone rolls on the fixed bearing E, and the larger on the
shaft projection d, the outward pressure on the set screw will be less than if the
larger roller also rolled on the fixed bearing; the speed of the live ring will also
be reduced.
Figure 6 is a part longitudinal section, and Figure 7 part transverse section and
part end elevation of a bearing in which each conical roller with its end shanks
is replaced by a ball a" preferably of hard steel. The roller paths e of the shaft it
and fixed part of bearing E may be curved in transverse section to a radius equal
to, or slightly greater than, that of the ball; the object being to increase the
pressure which each ball may safely transmit. The small portions of the roller
paths e in the neighbourhood of the geometrical points of contact of the balls
may be considered cones; the arrangement should be such that the vertices of
these tangent cones coincide at r. In order to provide for replacing a broken
ball without disturbing any other part of the mechanism, the set screw is of
diameter greater than that of the ball, so that the latter can be passed through
the screw-hole. The discs g are carried inside the set screw so as to keep
down the size of the live ring; as is clearly shown in Figure 6. The surface of
the disc in contact with the ball b may be made concave. The relative motion of
the parts and the mode of adjustment in the bearing described in Figures 6 and 7
are the same as in that described in Figures 1 and 2.
In cases where the diameter of the balls a" can be made small compared with
that of the shaft the radial thrust on each ball is small compared with the
longitudinal thrust; the discs may therefore be omitted, and the balls bear direct
against the live ring. The balls a need not be kept separate from each other, but
as great a number as is possible without jamming will be used, as in the ordinary
bicycle ball bearing. The bearing will then take the form illustrated in
Figures 8 and 9. This bearing will be self-adjusting; that is if the balls are all
of exactly the same diameter, and the two hardened steel conical paths e be
exactly co-axial, the longitudinal thrust along the shaft will cause all the balls to
be pressed equally outwards against the live ring. The motion of the balls
relative to the live ring is, in this case, the same as in the bearing illustrated in
Figures 6 and 7.
The smaller the diameter of the balls compared to that of the shaft, the greater
is the speed of rotation of the balls relative to the live ring, compared with the
speed of the shaft. The speed of rotation of the balls relative to the live ring,
and therefore also the risk of abrasion, may be diminished by having a number of
live rings in series between the shaft D and the fixed bearing E. Figure 10 is a
part longitudinal section of a thrust bearing of a screw shaft with a series of
three live rings carrying balls for the ahead direction of the shaft's motion, and
one live ring with balls for the astern direction. Loose double conical rings e¹
alternate with the rows of balls between the first and last rows.
The average
relative speed of two adjacent rings is divided by the number in the series of
rings; the average speed of rotation of the balls relative to the live rings is
therefore reduced in the same ratio. In this form of bearing the live rings may
carry balls or rollers of any of the forms herein before described.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. A thrust bearing formed by interposing, between suitable conical paths on the
shaft and fixed part of the bearing respectively, balis or conical rollers mounted
in a live ring; the outward radial pressure on each ball or roller being resisted

page_text: by an adjustable set screw in the said live ring, substantially as hereinbefore
described.
2. In a thrust bearing, the use of flat or lens-shaped discs between the outer.
end of each ball or conical roller and its corresponding set screw for the purpose
of reducing the relative motion and obviating abrasion of the working parts.
3. The methods of mounting the balls or rollers in the live ring of a thrust
bearing, so that one of the said balls or rollers may be removed or replaced
without interfering with any others; substantially as described and illustrated in
Figures 4, 6, and 7.
4. A thrust bearing formed by interposing, between suitable conical paths on
the shaft and fixed part of the bearing respectively, a number of balls which are
pressed outwards against a live ring; the arrangement of the surfaces in contact
being such that the relative motion of the balls and the two conical paths is one of
pure rolling, while that of the balls and the live ring is a pure pivot-like rotation,
substantially as described and illustrated in Figures 8 and 9.
5. A thrust bearing formed by interposing live rings of balls or rollers
alternately with loose hard steel double conical rings between the shaft and
the fixed part of the bearing, substantially as described and illustrated in
Figure 10.
6. In a thrust bearing with rollers or balls mounted in a live ring, the hollowing
away of the upper portion of the fixed roller path, so that the lubricant
may find its way between the working surfaces of the said rollers or balls and
live ring.
Dated this 13th day of November 1894.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.