Improvements in Variable Speed Gear.
Year: 1898

page_text: Date of Application, 16th Feb., 1898
Complete Specification Left. 15th Nov. 1898-Accented. 7th Jan
1800
Date of Application, 16th Feb., 1898
Complete Specification Left. 15th Nov. 1898-Accented. 7th Jan
1800
PROVISIONAL SPECIFICATION.
Improvements in Variable Speed Gear.
I, GEORGE FREDERICK REDFERN, of the Firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of London,
Patent Agents, do hereby declare the nature of this invention (a communication
to me by Emilio Borzini, of 2, Via Goito, Turin, in the Kingdom of Italy,
Engineer,) to be as follows:-
This invention relates to apparatus having for its object to transmit the move-
ment of a motor which rotates at uniform velocity to a shaft or other rotating
object, the velocity of which is to be capable of being varied gradually between
zero and a predetermined limit. To this end I utilize the relation which exists
between the velocity of relative displacement of a body with respect to a liquid
in which it is immersed and the pressure that the liquid exerts upon the solid
or vice versa.
The liquid can be displaced with respect to the solid and the latter remain at rest;
or the liquid may remain at rest and the solid may receive the motion: Further-
more, arrangements can be employed whereby the solid and the liquid are both
caused to move provided that there is always a relative movement between them
and in certain phases only tendency to such motion.
In a suitable arrangement for carrying out my invention, the essential parts
of the apparatus are:-
The
A pump which can be of any suitable type and a cock or other closing device
of any suitable kind, the area of the passage through which can be varied.
invention, however, is not limited to arrangements comprising the employment of
a pump and of a cock or the like with a passage of variable area as, as far as I am
aware, no successful attempt has hitherto been made to transform the uniform
motion of one part of a machine into variable motion between wide limits by
means of the resistance offered by liquids to the motion of solids immersed
therein.
In carrying out the invention I advantageously key upon a uniformly rotating
shaft one of the pistons or discs of a rotary pump. The pump body is rigidly
secured to a pulley the velocity of which is to be variable and the area of the
passage connecting the inlet and outlet openings of the pump can be regulated as
desired by operating a cock. With this arrangement when the cock is completely
closed, the motive shaft directly actuates the pulley and communicates its own
velocity to it as if a rigid clutch device were interposed between the shaft and the
pulley. If the maximum orifice has an area equal to the transverse section of
the passage so that the water does not meet with any appreciable resistance when
traversing it, the shaft will turn without rotating the pulley at all. If the cock
be turned so as to vary the area of the passage open to the water, the velocity of the
pulley can be varied as desired and by insensible degrees, that of the shaft always
remaining constant.
In a modified arrangement the pump and the cock, which should always be

page_text: ready to the hand of the attendant, can be kept stationary and by the interposition
of a train of gearing constituting a differential device. I am enabled to give
a maximum limit of velocity to the pump shaft and to the shaft in connection with
the useful resistance different from that of the motive shaft.
The motive shaft actuates a counterweighted disc which carries with it in its
rotation a small shaft upon which are keyed toothed wheels one of which gears
with a wheel keyed upon the driven shaft and the other of which gears with a
wheel keyed upon the shaft of one of the pistons or discs of the rotary pump, the
casing of which is stationary.
Assuming that the pump cock is closed, it is evident that the pump shaft,
and consequently the pinion keyed thereon, is prevented from turning and that the
pinion gearing with the latter will rotate both around its own axis and also around
the axis of the disc so that the velocity of the driven shaft will have its maximum
value, which can be easily calculated from the well known rule of Willis.
If now the pump cock be gradually opened the pump shaft will commence to
rotate and the velocity of the driven shaft will gradually diminish, the acceleration
on the one hand and the diminution on the other being always governed by the law
velocity of pump shaft
that amongst the infinite number of values that the relation
velocity of driven shaft
can assume, and only considering the kinematic connections of the parts,
the value, which for a given orifice of the cock will be real, will be that
to which the minimum value of the sum of the resistant forces for a given
value of the useful resistance corresponds. It is also obvious that when the
orifice of the cock becomes so great that the resistance of the pump can be
considered as practically nil, the pump shaft rotates with the maximum velocity
and the driven shaft does not rotate. If the useful resistance is varied for instance,
is increased, the pressure of the liquid in the pump tends to vary in the same
manner, that is to say, to increase this increase should produce, according to well
known laws, an increase in the velocity of the pump piston which, on account of
the kinematic connection existing between this piston and the driven shaft, effects
a diminution in the velocity of this latter in such a manner that, the orifice of the
cock remaining constant, the mechanism will automatically reduce the velocity at
the point to which the useful resistance is applied when the said resistance
increases in value and vice versa.
In order to keep the pump always full of liquid, I screw to its upper part a
compensating reservoir consisting of a metal cylinder containing a store of liquid
communicating with the interior of the pump through a passage which can be
closed by means of a screw valve.
The vessel or cylinder is provided with a level consisting of a glass tube and of
a filling plug; and also with an air valve. When the vessel is about two thirds
full of liquid the latter is subjected to pressure by means of an air pump secured
to the air valve so that the liquid is forced into the interior of the pump whilst
the air collects at the upper part of the compensator.
Dated the 16th day of February 1898.

page_text: Patent Agents, do hereby declare the nature of this invention (a communication
to me by Emilio Borzini, of 2, Via Goito, Turin, in the Kingdom of Italy,
Engineer), and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement: t
This invention relates to apparatus having for its object to transmit the move-
ment of a motor which rotates at uniform velocity to a shaft or other rotating
object, the velocity of which is to be capable of being varied gradually between
zero and a predetermined limit. To this end I utilize the relation which exists
between the velocity of relative displacement of a body with respect to a liquid
in which it is immersed and the pressure that the liquid exerts upon the solid
or vice versa.
The liquid can be displaced with respect to the solid and the latter remain at rest;
or the liquid may remain at rest and the solid may receive the motion. Further-
more, arrangements can be employed whereby the solid and the liquid are both
caused to move provided that there is always a relative movement between them
and in certain phases only tendency to such motion.
My apparatus comprises a pump which can be of any suitable type and a cock
or other closing device of any suitable kind, the area of the passage through which
can be varied.
In the accompanying drawings:-
Figures 1 and 1B represent respectively a side view (partly in section) and a
transverse section of one form of my apparatus.
Figure 2 is a longitudinal section of a modified form of my apparatus.
Figure 2 is a transverse section on the line X-Y of Figure 2 and
Figure 2 is a front elevation of the same.
Figure 3 is a section of a compensating reservoir hereinafter described.
Referring first to Figures 1 and 12, 13 is the rotating shaft designed to actuate
the pulley with a velocity which varies as desired between zero and the velocity
of the shaft B. Upon the said shaft B there is keyed one of the pistons or discs
of a rotary pump A. The pump body is rigidly secured to the pulley D the
velocity of which is to be variable and the area of the passage a, a connecting the
inlet and outlet openings of the pump can be regulated as desired by operating
a cock F. With this arrangement when the cock F is completely closed; the
motive shaft B directly actuates the pulley D and communicates its own velocity
to it as if a rigid clutch device were interposed between the shaft B and the
pulley D. If the maximum orifice has an area equal to the transverse section of
the passage a so that the water does not meet with any appreciable resistance
when traversing it, the shaft B will turn without rotating the pulley D at all.
If the cock F be turned so as to vary the area of the passage open to the water,
the velocity of the pulley D can be varied as desired and by insensible degrees,
that of the shaft B always remaining constant.
I
In the modified and more simple arrangement illustrated in Figures 2*, 2 and 20,
which is more suitable for practical purposes the pump and the cock, which
should always be ready to the hand of the attendant, can be kept stationary, and,
by the interposition of a train of gearing constituting a differential device, as
hereinafter described, I am enabled to give a maximum limit of velocity to the
pump shaft and to the shaft in connection with the useful resistance different
from that of the motive shaft.
In this arrangement the motive shaft which rotates with uniform velocity is
shewn at Z. C is the shaft which is to be rotated with a velocity which can be
varied as desired. The arrangement is not altered if the movement is communi-
cated from C to Z with a variable speed connection.
The motive shaft Z actuates a counterweighted disc B₁ which carries with it in
its rotation a small shaft e upon which are keyed toothed wheels b and c one of
which (c) gears with a wheel d keyed upon the driven shaft 'C and the other of
which (b) gears with a wheel a' keyed upon the shaft M of one of the pistons or

page_text: discs of the rotary pump A, A, the casing of which is stationary. E is the
counterweight connected to the disc B¹.
Assuming that the pump cock F is closed, it is evident that the pump shaft M,
and consequently the pinion a keyed thereon, is prevented from turning and that
the pinion gearing with the latter will rotate both around its own axis and also
around the axis of the disc so that the velocity of the driven shaft C will have
its maximum value, which can be easily calculated from the well known rule
of Willis.
If now the pump cock F be gradually opened the pump shaft M will commence
to rotate and the velocity of the driven shaft C will gradually diminish, the
acceleration on the one hand and the diminution on the other being always governed
velocity of M
by the law that amongst the infinite number of values that the relation-
velocity of C
can assume, and only considering the kinematic connections of the parts, the
value, which for a given orifice of the cock F will be real, will be that to which the
minimum value of the sum of the resistant forces for a given value of the useful
resistance corresponds. It is also obvious that when the orifice of the cock F
becomes so great that the resistance of the pump can be considered as practically
nil, the pump shaft M rotates with the maximum velocity and the driven shaft C does
not rotate. If the useful resistance is varied, for instance if it is increased, the pressure
of the liquid in the pump tends to vary in the same manner, that is to say, to
increase; this increase should produce, according to well known laws, an increase
in the velocity of the pump piston which, on account of the kinematic connection
existing between this piston and the driven shaft C, effects a diminution in the
velocity of this latter in such a manner that, the orifice of the cock remaining
constant, the mechanism will automatically reduce the velocity at the point to
which the useful resistance is applied when the said resistance increases in value
and vice versa.
It is evident that the operation of the arrangements represented in Figures 1
and 2 is dependent upon the perfect tightness of the packing of the pump and upon
its rigidity.
In order to keep the pump always full of liquid, I screw to its upper part a
compensating reservoir (Figures 3 and 2") consisting of a metal cylinder V contain-
ing a store of liquid communicating with the interior of the pump through a
passage G which can be closed by means of a screw valve U.
The vessel or cylinder V is provided with a level consisting of a glass tube R and
of a filling plug T; the screw threaded hole S is closed by an air valve which
is not shewn in the drawing. When the vessel V is about two thirds full of liquid
the latter is subjected to pressure by means of an air pump secured to the
passage S; the valve U being open, the liquid is forced into the interior of the
pump through the passage G whilst the air which might enter the pump collects
at the upper part of the compensator. When the valve U is closed it is a proof
that the pump is completely filled.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In apparatus for transforming the constant rotary movement of a shaft into a
rotary movement, the velocity of which can be gradually varied, wherein the
transmission is effected through the medium of a liquid maintained in movement
relatively, to a solid immersed therein, the employment of a pump circulating a
liquid which is forced through a valve or cock with a passage of variable area,
substantially as set forth.
2. Apparatus of the kind described in Claim 1 wherein the pump body is rigidly
secured to the variable speed shaft and the piston (or one of the discs of the pump,
if a rotary pump is employed) is rigidly secured to the motive shaft which rotates

page_text: at constant velocity of vice versa, substantially as set forth and illustrated in
Figures 1 and 1" of the accompanying drawings.
3. An apparatus of the kind described in Claim 1 wherein the pump body is
stationary a train of epicycloidal gear, constituting a differential apparatus as
herein described being interposed between the piston or other movable part of the
pump and the shaft to which a variable velocity is to be communicated, whereby
the movement of the constant velocity shaft is divided according to a variable
law depending upon the resistance offered to the movement of the pump piston
between this said piston and the shaft to be driven, substantially as hereinbefore
described and illustrated in Figures 2^, 2" and 2° of the accompanying drawings.
Dated the 15th day of November 1898.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.