IMPROVEMENTS IN UPRIGHT AND FOOTSTEP BEARINGS AND THE MEANS FOR RELIEVING THE PRESSURE OF THE SHAFTS THEREUPON
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincoln's Inn Fields in the
County of Middlesex Gentleman for an invention of "IMPROVEMENTS IN
UPRIGHT AND FOOTSTEP BEARINGS AND THE MEANS FOR RELIEVING THE
PRESSURE OF THE SHAFTS THEREUPON A communication from abroad by
"
Albert Fosca of Berlin in the Empire of Germany
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 4th April 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN UPRIGHT AND FOOTSTEP BEARINGS AND THE MEANS
FOR RELEIVING THE PRESSURE OF THE SHAFTS THEREUPON," a communication
from abroad by Albert Fesca of Berlin in the Empire of Germany
In working centrifugal machines with vertical shafts it has been found by
experience that the footstep bearings wear longer and are better able to work
under beavy pressure when the heel or lower extremity of the shaft is provided
with a stud or pivot of hard steel presenting a convex surface and working upon
a corresponding bearing plate or disc of hard bronze:-
Footstep bearings of this description produce a small amount of frictional
resistance between the shaft and the bearing plate and are found to wear well
when the shaft makes from seven hundred to eight hundred revolutions per minute
with a load of from about one ton to one and a half tons or when a higher speed
is employed providing that the load is correspondingly reduced. On the other
hand these bearings do not admit of the shaft being caused to make from seven
hundred to eight hundred revolutions per minute when the load is increased to
about two tons as there are no known materials which would be capable of being
employed to form the heel and bearing plate without rapidly wearing away under
these conditions:
The object of the present invention is to partially or wholly remove the direct
pressure of the heel or end of the shaft upon the footstep or bearing plate by
hydraulic power and to enable this to be performed by a suitable arrangement of

page_text: apparatus hereinafter described whereby in the construction of centrifugal machines
for example it is rendered possible to provide for the rotation of very heavily
loaded shafts at the desired speed:
In carrying out this Invention as applied to the footstep bearing of a shaft of a
centrifugal machine, for example in which the upper extremity of the shaft is
supported in an elastic or moveable bearing, and partakes of an oscillating motion
the apparatus is constructed as next hereinafter described:
A ring is suspended by and turns upon horizontal trunnions mounted in strong
bearings. Two bearings are formed in the said ring in which bearings work two
trunnions carrying a footstep bearing which is thus enabled to turn in any
direction (being supported by an arrangement analogous to the gimbals of the
Mariners compass) and allow the shaft mounted therein to oscillate:
A bearing plate is arranged in the bottom of the bearing and is provided with
a perforation or perforations serving to connect the space above the bearing plate
with a cavity in the underside of the said plate.-The lower extremity of the shaft
is provided with a bearing stud or pivot and is slightly tapered the smallest
diameter being at the lower part: The socket of the bearing is of corresponding
form and the shaft is fitted to the socket so as to prevent leakage from taking
place between their surfaces in any position which the stud or pivot on the shaft
end may assume upon the bearing plate.
The footstep bearing is provided at its upper end with an oil chamber covered
in at the top and provided with an overflow tube for the escape of the excess
of oil.
Pumping apparatus is employed to draw oil from a reservoir and force it through
a delivery pipe into the footstep bearing under the end of the shaft:
The pumps are preferably arranged to produce a continuous flow of oil. A high-
pressure delivery pipe extends from the pump to one side of the footstep bearing
and communicates with the cavity hereinbefore described in the underside of the
bearing-plate. In order that the connections of the delivery pipe with the pump
and with the bearing may not be liable to leak when the axis of the shaft and
consequently the bearing oscillate or partake of lateral motion the said pipe is bent
into a number of convolutious or sinuosities for the purpose of allowing it to yield
without straining the joints. The continuous stream of oil forced by the pump to
the bearing passes up through the holes in the bearing plate under the extremety
of the shaft and exerts on the latter a pressure which should be slightly in excess
of the load upon the said shaft: Under these conditions the pressure of the oil
tends to lift the shaft out of its socket, until it finds an outlet.
The degree of taper of the extremity of the shaft and of the socket or bearing
as well as the pressure of oil are so arranged that a slight lifting or displacement
of the shaft in the direction of its length within the socket is sufficient to produce
an annular passage for the escape of the oil upwards between the shaft and the
socket by reason of the conical shape of the latter of such an area that the oil
flowing through this passage shall meet with just so much frictional resistance as
to establish an equilibrium between the total pressure of the oil against the end of
the shaft on the one hand and the amount of the load upon the latter plus the
frictional resistance which the oil has to overcome in its passage on the other
hand:
.
The pressure under which the pump delivers the oil may actually exceed the
load upon the shaft to any extent as it is merely necessary to so adjust the speed
of the pump and consequently the speed of the stream of oil that the same shall be
so great as to render it impossible with a suitable amount of taper on the shaft
and a corresponding tightness of the fit between it and the socket for the oil to
escape so long as the end of the shaft rests upon the bearing plate. The equilibrium
of pressure is thus automatically established and maintained when the taper
extremity of the shaft is lifted to a certain extent and is supported by the oil and
when so lifted affords a passage for the oil of such an area as to produce the
required frictional resistance.

page_text: The oil escaping at the upper part of the apparatus is collected in a chamber.
whence it flows along an overflow pipe, and through a channel back to the oil
reservoir and thus circulates continually through the pump the delivery pipe and
the bearing:
It is evident that the pumps must be set to work before the shaft commences to
revolve and that the shaft must be stopped before the action of the pumps is
discontinued in order, the end of the shaft may be continually lifted by the oil so
long as the former is in motion :
In order to provide against possible negligence on the part of the attendants to
attend to this condition and prevent the consequent injury to the apparatus and at
the same time to enable the pressure at which the oil is delivered to be adjusted
with greater precision an accumulator may be employed between the pumps and
the apparatus the said accumulator being constructed and arranged in precisely the
same manner as the accumulators ordinarily employed for lifts or hoisting
purposes.
The load upon the piston of this accumulator will correspond to the pressure
which it is necessary to exert against the end of the shaft and by this means it is
rendered possible, first, to exert sufficient. pressure on the end of the shaft that
although in contact with the bearing plate it turus upon the latter with little or
no friction or secondly, to lift the end of the shaft entirely out of contact with its
bearing; or again, thirdly, to allow it to rest upon its bearing plate with any
desired amount of pressure and consequent friction:
The escape of the oil from the bearing may in certain cases be entirely prevented
and for this purpose the extremity of the shaft must be made cylindrical instead
of taper and must be passed through a stuffing box:
When an accumulator is employed it will be easy to provide an arrangement by
means of which the piston of the accumulator when in its highest position may be
caused to throw the pump out of action and thus automatically regulate the supply
of oil.
The Invention is applicable to all descriptions of heavily loaded upright shafts
and in place of the oil, soap and water, water or any other liquid may be
employed

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
3rd October 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN UPRIGHT AND FOOTSTEP BEARINGS AND THE MEANS
FOR RELIEVING THE PRESSURE OF THE SHAFTS THEREUPON a communication
from abroad by Albert Fesca of Berlin in the Empire of Germany.
">
In working centrifugal machines with vertical shafts it has been found by
experience that the footstep bearings wear longer and are better able to work
under heavy pressure when the heel or lower extremity of the shaft is provided
with a stud or pivot of hard steel presenting a convex surface and working upon a
corresponding bearing plate or disc of hard bronze.
Footstep bearings of this description produce a small amount of frictional
resistance between the shaft and the bearing plate and are found to wear well
when the shaft makes from seven hundred to eight hundred revolutions per minute
with a load of from about one ton to one and a half tons or when a higher speed is
employed providing that the load is correspondingly reduced. On the other hand
these bearings do not admit of the shaft being caused to make from seven hundred
to eight hundred revolutions per minute when the load is increased to about two
tons as there are no known materials which would be capable of being employed
to form the heel and bearing plate without rapidly wearing away under these
conditions.
The object of the present Invention is to partially or wholly remove the direct
pressure of the heel or end of the shaft upon the footstep or bearing plate by
hydraulic power and to enable this to be performed by a suitable arrangement of
apparatus hereinafter described whereby in the construction of centrifugal machines
for example it is rendered possible to provide for the rotation of very heavily
loaded upright shafts at the desired speed.
And in Order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of Drawings the same letters of reference
indicating corresponding parts in all the figures.
The said Drawing illustrates an example of the application of this Invention to
a centrifugal machine the upper extremity of the shaft of which is supported in an
elastic, or moveable, or it may be in a rigid, bearing whether the said shaft
partakes of an oscillating motion or not. A footstep bearing as constructed
for the oscillating description of shaft is illustrated in the example shewn in the
Drawing.
Figure 1 is a vertical section; Figure 2 is an elevation at right angles to
Figure 1 and Figure 3 is a plan of a footstep bearing and connections arranged
according to this Invention, Figure 4 is a section and plan of the bearing drawn to
a larger scale.
In two strong bearings a a (Figures 2 and 3) a ring b is suspended turning upon
trunnions bb working in the said bearings a a. Two bearings c c¹ are formed
in the ring b in which bearings work two trunnions e e¹ carrying a footstep
bearing d (Figs. 1234) which is thus enabled to turn in any direction (being
supported by an arrangement analogous to the gimbals of the mariner's compass)
and allow the revolving shaft to oscillate to the required extent.
A bearing plate f is arranged in the bottom of the. bearing d and is provided
with a perforation or a series of perforations arranged in a circle as at g. g and
serving to connect the space above the bearing plate ƒ with an annular cavity / in
the under side of the said plate f.
The lower extremity i of the shaft is provided with a bearing stud or pivot the
lower part of the said shaft being slightly tapered the smallest diameter being at
the lower part as shewn. The socket of the bearing d is of a corresponding form

page_text: and the shaft is fitted to the said socket with the greatest nicety so as to give a
tight fit and prevent leakage between them when the stud at the end of the
shaft bears upon the plate f.
The bearing d is provided at its upper part with an oil chamber d¹ covered in at
the top and provided with an overflow tube d" for the escape of the excess of oil.
K K K represents a compressed pump which draws oil or other suitable liquid
from a reservoir and forces it through the common delivery pipe n into the
footstep bearing & under the end of the shaft.
The pump is actuated by a shaft A provided with cranks or excentrics so timed
as to work the plungers of the pump to produce a continuous flow of liquid. The
delivery pipen extends from the pump to one side of and below the footstep
bearing d and communicates with the annular cavity in the underside of the
bearing plate. In order that the connections of the delivery pipe with the pump
and with the bearing may not be liable to leak when the axis of the shaft oscillates
or partakes of lateral motion the said pipe is bent into a number of convolutions or
sinuosities for the purpose of allowing it to yield without straining the joints.
The continuous stream of liquid forced by the pump K along the pipe n into the
cavity h passes up through the holes g underneath the extremity of the shaft i and
exerts thereon a pressure the amount of which depends upon the power of the
pump and the area of the pistons and the area of the under surface of the end of
the shaft i. The said pressure should be slightly in excess of the load upon the
shaft Under these conditions the pressure of the liquid tends to lift the shaft out
of its socket until it finds an outlet sufficiently large to enable the said liquid to
escape at a speed and under a pressure corresponding to that at which it is
delivered by the pumps.
The degree of taper of the extremity of the shaft i and of the socket or bearing d
as well as the pressure of liquid are so arranged that a slight lifting or displacement
of the shaft in the direction of its length within the socket d is sufficient to
produce an annular passage for the escape of the oil upwards between the shaft
and the socket (by reason of the conical shape of the latter) of such an area that
the liquid flowing through this passage shall meet with just so much frictional
resistance as to establish an equilibrium between the total pressure of the liquid
against the end of the shaft on the one hand and on the other hand the amount of
the load upon the latter plus the frictional resistance which the liquid has to
overcome in its passage.
The pressure under which the pump delivers the liquid may exceed the load
upon the shaft to any extent as it is merely necessary to so adjust the speed of
the pump and consequently the speed of the stream of liquid that the same shall
be so great as to render it impossible with a suitable amount of taper on the shaft
and a corresponding tightness of the fit between it and the socket for the liquid to
escape so long as the end of the shaft rests upon the bearing plate. The equilibrium
of pressure is thus automatically established and maintained when the taper
extremity of the shaft is lifted to a certain extent and is supported by the liquid
and when so lifted affords a passage for the liquid of such an arca as to maintain
the required conditions.
The liquid escaping at the upper part of the apparatus is collected in the
chamber d whence it flows along the overflow pipe du into a shoot or pipe m back
to the reservoir and thus circulates continually through the pump the delivery
pipe and the bearing.
It is evident that the pump should be set to work before the shaft commences to
revolve and that the shaft must be stopped before the action of the pumps is
discontinued in order that the end of the shaft may be continually lifted by the
liquid so long as the former is in inotion.
In order to provide against possible negligence on the part of the attendants to
attend to this condition and prevent the consequent injury to the apparatus and at
the same time to enable the pressure at which the liquid is delivered to be adjusted
with greater precision an accumulator may be employed between the pump and the

page_text: apparatus the said accumulator being constructed and arranged in the same manner
as the accumulators ordinarily employed for lifts or hoisting purposes-The load
upon the piston of this accumulator will correspond to the pressure which it is
necessary to exert against the end of the shaft and by this means it is rendered
possible first, to exert sufficient pressure on the end of the shaft that although in
contact with the bearing plate it turns upon the latter with little or no friction or,
secondly, to lift the end of the shaft entirely out of contact with its bearing or,
thirdly, to allow it to rest upon its bearing plate with any desired amount of
pressure and consequent friction.
The escape of the oil from the bearing may in certain cases be entirely prevented
and for this purpose the extremity of the shaft must be made cylindrical instead of
taper and must be passed through a stuffing box.
When an accumulator is employed it will be easy to provide an arrangement by
means of which the piston of the accumulator when in its highest position may be
caused to throw the pump out of action and thus automatically regulate the supply
of liquid.
The Invention is applicable to all descriptions of loaded upright shafts and oil,
soap-and-water, water, or any other liquid suited to the purpose may be employed.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is:
First Partially or wholly relieving the pressure of shafts on, or in, footstep
bearings by passing or forcing a liquid to between the said shaft and the bearing
substantially as herein before described.
Secondly: The means for wholly or partially relieving the pressure of shafts on
or in footstep bearings consisting in the employment of a liquid forced by means
of a pump or the equivalent thereof (with or without an accumulator) to between
the lower end of the shaft and the bearing in combination with means for allowing
excess of liquid to escape through the passage formed in consequence of this lifting
between the socket and shaft end and be returned to the pump or equivalent
receiver so as to maintain a circulation and constant action of the said liquid
substantially as hereinbefore described,
Thirdly: The footstep bearing for centrifugal or other machines fitted to the
conical extremity of the shaft and supported in gimbal-like bearings in order to
allow of the lateral motion of the elevated centre of gravity of the centrifugal or
other machine in combination with the bearing plate f provided on its underside
with a cavity which gives communication for a liquid to the space between the said
plate and the bearing end of the shaft substantially as hereinbefore described and
illustrated in the accompanying drawings.
Fourthly In footstep bearings of the kind hereinbefore described connecting the
bearing on the one hand with pumping or equivalent forcing apparatus by means
of a tortuous pipe and on the other hand with a chamber d¹ and overflow pipe d"
for conducting the excess of oil or other liquid back to the pump in order to obtain
a constant supply of liquid under pressure and at the same time allow of the
requisite oscillation or movement of the shaft and bearing substantially as
herein before described.
In witness whereof I- the said John Henry Johnson have to this my
Specification set my hand and seal this third day of October One
thousand eight hundred and eighty-two.
J. HENRY JOHNSON (L.S.)