Improvements in connection with Thrust-blocks and similar Bearings.
Year: 1890

page_text: Date of Application, 4th Oct., 1890
Complete Specification Left, 3rd Dec., 1890-Accepted, 3rd Jan., 1891
PROVISIONAL SPECIFICATION.
Improvements in connection with Thrust-blocks and similar
Bearings.
We, CHARLES SCOTT SNELL, of Culver Park, Saltash, Cornwall, and BERNARD
MORLEY FLETCHER of 25 Great George Street Westminster, S.W., Engineers, do
hereby declare the nature of this invention to be as follows:-
The object of this invention is to allow the variation in the thrust, or pull on
the shaft of a screw propeller (or that of a windmill or turbine axle or similar
appliances, in which the variations in the work done more or less directly affects
such thrusting or pulling action in a like varying ratio) to be utilized to control the
amount direction or influence of the actuating medium employed. For instance, in
a steam driven marine engine to control the quantity or pressure at which the steam
shall be supplied or other factor governing the rate or power-or the electro-motive-
force or current in the case of an electrically driven launch, or petroleum, oil, gas,
hydraulic, heat, or other motive force under similar conditions.
In windmills to trim, set, or otherwise control the angle or amount of the sails to
snit the requirements of the work demanded.
In turbines to control the penstock bypass, apply a brake, or otherwise as may be
desired to proportion the motive power supplied, to the demand of the moment.
it
For this purpose we make use of a thrust-block, footstep-bearing or other usual
or suitable arrangement which admits of free or convenient rotation, but instead of
fixing it to an adjacent and relatively immoveable bed or base, we prefer to mount
up in a manner admitting of a certain amount of end-movement, (preferably very
small) such movement, or the pressure, thrust, or pull tending to cause such move-
ment, being utilized to compress or similarly affect, (by means of conveniently fixing
hydraulic rams, springs, weights, compressing cylinders and pistons, electrical or
other suitable appliances) a suitable medium, such as water, oil or other convenient
connection in such a manner that the variations in force thereon may be readily
shown on a guage or other convenient instrument, and may be utilized to actuate
suitable intermediate links which will be placed directly or indirectly in connection
with the valves, sluices or water gates, throttles, sail-shifters or other appliances
which may be arranged to control the motive power employed.
It will be seen that in this method there is no necessity to interpose any inter-
mediate mechanism affecting the relative angular positions between the driven and
driving portions of the machine, and that whilst there is no tendency to backlash or
play, absolute control is readily effected.
Dated this 4th day of October 1890.
C. SCOTT SNELL.
B. MORLEY FLETCHER.
COMPLETE SPECIFICATION.
Improvements in connection with Thrust-blocks and similar
Bearings.
We, CHARLES SCOTT SNELL of Culver Park Saltash Cornwall, and BERNARD
MORLEY FLETCHER of 25 Great George Street Westminster S.W., Engineers, 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:-
The object of this invention is to allow the variation in the thrust, or pull on the
shaft of a screw propeller, (or shaft of a windmill, or turbine axle or similar

page_text: appnances, in which the variations in the work done more or less affect directly such
thrusting or pulling action in a like varying ratio), to be utilized to control the
amount, direction, or influence of the actuating medium employed.
Reference is made to the accompanying drawings, in which
Fig. 1 is a side elevation, Fig. 2. a plan, and Fig. 3 a section of a thrust block for
a marine engine.
Fig. 4 is a side elevation, and Fig. 5 a plan of a similar apparatus for smaller
powers.
Fig. 6 is a section of a turbine axle bearing and Fig. 7 a side elevation of a
windmill axle.
In Figs. 1, 2 & 3, similar letters refer to similar parts, and it will be seen that A
is the propellor, B the main shaft, C the crank axle with a coupling D (of any
convenient nature for admitting of slight longitudinal motion without side play),
E is a thrust block with detachable cover, bearings, lubricating arrangements, and the
usual accessories to any ordinary thrust block; it will be noticed however, that instead
of being rigidly fixed to a bed, or base it is mounted up so as to admit of a certain
amount of end movement or travel, (see Fig. the thrust block E. working in the
prepared bed 1), the motion in the direction shown by the arrows is taken up by the
hydraulic cylinders H, in which work plungers G attached by lugs F to the thrust
block E. It will be seen that as the thrust on the block increases the water, (or if
desirable oil or other liquid may be used), in the cylinders communicating by the
pipes J with the reservoir K and cylinder M, causes the piston therein to rise, com-
press the adjustable spring N, and actuate the rod O through the bell-crank P. This
movement once obtained may of course be used to proportion or govern the power
driving the propellor, and it follows that if the stern of the vessel is raised out of the
water, the thrust on the block and accessories will become lessened, and the spring N
reverse all the preceding motions and turn the power off, thus preventing "racing."
At Q Fig. 1'is shown a recording drum and pencil for indicating purposes.
The reversing of the engines will cause a pressure upon the lugs R. and the con-
trolling mechanism may, if wished, be temporarily thrown out of gear; there is no
jar in this reversing, as the thrust block at rest is always pushed back against the said
lugs, at the same time, although not illustrated, it is evident that these lugs might be
replaced by a similar set of cylinders coming into action when the engines are
reversed.
It is not of course necessary to keep this governing mechanism always in action,
and in the event of leakage, or breaking of a pipe, no great injury is inflicted, the
whole working merely as an ordinary thrust block: by the continuous use of this
apparatus a break in the main shaft or loss of propellor would immediately cause the
power, (steam or otherwise), to be partially or wholly turned off as may have been
previously arranged.
Referring to Figs. 4 & 5, letters thereon, similar to letters on the other figs., refer
to equivalent portions; practically the whole action is in each case identical; springs
however replacing the hydraulic gear.
To fill the cylinders in the first described arrangement, and to make up for loss
by breakage or evaporation, the pipe L is used in connection with a pump which
would be used to force in sufficient water to raise the pencil on the drum Q Fig. 1 to
zero.
In Fig. 6 is shown the section of a footstep bearing for a turbine or any similar
appliance using a vertical axle upon which the thrust is proportional to the work
done. The axle is shown at B. with a liner E.
And a pistons G compress the fluid in the cylinders H and through the pipe J
communicating with a cylinder M the vertical force on the axle B raises the piston
in cylinder M, and thereby controlls or actuates any supplementary appliances
affecting the power used. For instance, it may operate a penstock in connection
with a bye pass thus affecting the head of water working the turbine, or in any other
convenient manner regulate the power developed.
In Fig. 7 is shown a horizontal axle B. applicable to a windmill, in which the

page_text: thrust block E slides along a bed 1 after the manner described for a marine engine
but this travel is utilized to raise a weight N and turn thereby the wheel H causing
the rod to receive a proportional movement, which may be utilized in any con-
venient way to trim, set, or otherwise control the angle or amount of the sails to suit
the requirements of the work demanded.
Now it will be readily understood that although for clearness we describe the
application of hydraulic cylinders in one case, weights in another, and springs in a
third, we do not confine ourselves entirely or wholly to the combination shown;
obviously, though in some cases less conveniently, the different reaction forces may
be interchanged, and supplementary attachment may be likewise added, as for
instance, air vessels in the hydraulic cylinders or compressed air instead of water or
oil may be used as a medium; and admitting that by each, or any, or any com-
bination of the above described appliances, we have a shaft, with an end pull or
thrust more or less proportional to the work done, mounted up in such a manner that
a rod or lever in connection therewith receives a similar relative movement or force,
it is clear that such a rod can be adapted directly or indirectly to exercise a corre-
sponding control over the motive power, whether water, gas, steam, electricity, (say
by varying the resistance in the circuit), petroleum, heat, or other actuating medium,
through intermediate valves, taps, switches, sail shifters, penstocks, or other suitable
mechanism for the respective motive powers.
It will be seen that in this method there is no necessity to interpose any inter-
mediate mechanism affecting the regular angular positions between the driven and
driving portions of the machine, and that whilst there is no tendency to backlash or
play therein, continuity being kept as regards torsional strain on the axle, yet by
admitting of and utilizing the end movement of the thrust block or its equivalent, the
motive power is readily controlled.
In all cases in which thrust is mentioned we use it in the sense that it is applied
in the usual term thrust block, that is-applicable to pulling as well as to thrusting.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:―
First. The construction or arrangement, and combination of the parts, which form
or are accessories of a thrust block or its equivalent, so that longitudinal motion is
allowed, which is utilized to actuate or control mechanism affecting the motive power,
in such a manner that this said motion is more or less varied to suit the requirements
for which it may be arranged, substantially as and for the purposes described and
illustrated in the accompanying drawings.
Second. The combination with the above described arrangement of a recording
drum and pencil or the like indicating devices for the purpose of obtaining such
data as may thereby be furnished or deduced, substantially as and for the purposes
described and illustrated in the accompanying drawings.
Third. The mounting up of thrust blocks or accessories thereto or equivalent thrust
receiving mechanisms in such manner as to admit of motion in the direction of the
shaft, in contradistinction to the usual rigidity of such mechanism, substantially as and
for the purposes described and illustrated in the accompanying drawings.
Fourth. The controlling of the motive power through springs, weights, hydraulic,
electrical or equivalent means, actuated by the longitudinal thrusting or pulling
action, substantially as and for the purposes described and illustrated in the
accompanying drawings.
Deted this 3rd day of December 1890.
C. SCOTT SNELL.
B. MORLEY FLETCHER.