Improvements in and connected with Adjustable Excentrics or Crank Pins.
Year: 1889

page_text: Date of Application, 23rd Apr., 1889
Complete Specification Left, 23rd Jan., 1890-Accepted, 1st Mar., 1890
PROVISIONAL SPECIFICATION.
°
Improvements in and connected with Adjustable Excentrics or
Crank Pins.
I, GEORGE HORATIO TOWNSEND BEAMISH of Spyhill House, Queenstown Ireland
do hereby declare the nature of this Invention to be as follows:-
The object of my Invention is to provide means whereby the throw of an excentric
or of a crank pin can be altered readily and if desired whilst the machine is in
motion.
According to my Invention I employ two excentrics one of which is secured to the
shaft and the other of which encircles the one so secured to the shaft. Surrounding
the said shaft or a portion of its length is a tube or sleeve which can be moved round
on the shaft, and the said tube or sleeve is provided with gearing, levers, or equivalent
devices whereby the outer excentric is moved round upon the inner excentric as the
said tube or sleeve is moved round on the shaft and so the relative positions of the
centres of the two excentrics are altered to give any desired throw to the outer
excentric or to the crank pin which may be used therewith if the part constituting the
outer excentric be used as a crank disc. prefer to operate the said sleeve or tube
by making in it a helical groove or guide and in the shaft a straight groove or guide
in both of which engages a projection from a sliding ring encircling the said tube or
sleeve and capable of being moved longitudinally along the said tube or sleeve so that
the action of the projection on the ring causes the said sleeve or tube to have imparted
to it the rotary movement for the purpose described. The device by which this
movement is conveyed to the outer excentric may consist of a gear wheel on the sleeve
or tube gearing with another wheel fixed to, or forming part of an arm or lever
centered to the inner excentric and at its outer end connected to the outer excentric so
that when it is operated it adjusts the said outer excentric relatively to the inner one
or where it is not required to make the adjustment while the shaft is revolving; the
adjustment may be made by means of a worm and worm wheel, the worm being
secured to one of the excentrics and the worm wheel fitted on the other excentric.
I do not limit myself to the precise means which I have described of giving motion to
the sleeve and of conveying the movement thereof to the outer excentric as they may
be varied without departing from the nature of my Invention, but I believe those
which I have described will be found most convenient in practice.
Data: 1
A 1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Improvements in and connected with Adjustable Excentrics or
Crank Pins.
I GEORGE HORATIO TOWNSEND BEAMISH of Spyhill House Queenstown Ireland 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 my Invention is to provide means whereby the throw of an eccentric
or of a crank pin can be altered readily and if desired whilst the machine is in
motion.
According to my Invention I employ two eccentrics one of which is secured to the
shaft and the other of which encircles the one so secured to the shaft. Surrounding
the said shaft or a portion of its length is a tube or sleeve which can be moved round
D

page_text: on the shaft and the said tube or sleeve is provided with gearing, levers or equivalent
devices whereby the outer eccentric is moved round upon the inner eccentric as the
said tube or sleeve is moved round on the shaft and so the relative positions of the
centres of the two eccentrics are altered to give any desired throw to the outer
eccentric or to the crank pin which may be used therewith if the part constituting
the outer eccentric be used as a crank disc.
I prefer to operate the said sleeve or tube by making in it a helical groove or
guide and in the shaft a straight groove or guide or a helical groove arranged in the
reverse direction to the groove in the sleeve in both of which grooves engages a
projection from a sliding ring encircling the said tube or sleeve and capable of
being moved longitudinally along the said tube or sleeve so that the action of the
projection on the ring causes the said sleeve or tube to have imparted to it the rotary
movement for the purpose described.
I will describe my Invention with reference to the accompanying drawings,
premising however that I do not restrict myself to the details of construction illustrated
and hereinafter described.
Figure 1 is a side elevation and Figure 2 a longitudinal section of an arrangement
for varying the throw of an eccentric according to my Invention and Figure 3 is a
view similar to Figure 1 illustrating the Invention applied to the adjustment of a
crank pin.
Referring to Figures 1 and 2, A. represents a portion of an engine shaft having
keyed thereon an eccentric B provided on its periphery with a groove bin which is
mounted an outer eccentric C. This outer eccentric is preferably made in parts for
convenience of fitting it on to the inner eccentric, the parts being connected together
by bolts a as shewn, or in any other suitable manner. On the shaft A there is fitted,
so as to turn thereon, a sleeve D) having fast on one end a pinion E gearing with a
corresponding pinion E2 or teeth attached to or formed on the boss F of an arm or
lever G mounted on a stud H projecting from the centre of the inner eccentric or
disc B. The outer end of this arm is attached at c to the outer eccentric C. The
stud H constitutes the axis of the outer eccentric C, round which axis it may be
turned to vary the degree of eccentricity with respect to the shaft, A.
As shewn by full lines in Figure 1, the motion of the two eccentrics are neutralised
and consequently the stroke is nil. and no motion will be given to the piston or other
mechanism connected to the eccentric strap d. By shifting the outer eccentric C
round the inner eccentric B either to the right or to the left, as most convenient (for
example as shewn by dot and pick line in Figure 1) the eccentricity of the eccentric C
with respect to the shaft A. being increased more or less according to the angle or
degree to which the long radius of the outer eccentric is caused to assume with
reference to the long radius of the inner eccentric B and consequently the stroke or
motion imparted to the piston or other mechanism connected to the eccentric strap d
will accordingly be greater or less, and when the long radius of the outer eccentric is
brought in line with the long radius of the inner eccentric, but on the opposite side of
the shaft to that shewn by full lines in Figure 1, the stroke of the eccentric will be
at the maximum. A convenient way according to my Invention, of adjusting the
position of the outer eccentric C, on the inner eccentric B, is shewn in the drawings and
consists in providing in the sleeve D carrying the pinion E, a helical groove e, (or
helical grooves) and in the shaft A, surrounded by the said sleeve, there is provided a
straight groove or grooves, or a helical groove or grooves, arranged in the reverse
direction to the groove or grooves e in the sleeve. Fitted to slide along the sleeve D
is a collar I having in the interior thereof a stud or projection or projections g which
passes or pass through the groove or grooves e in the sleeve into the groove or
grooves in the shaft A. so that by sliding this collar along the sleeve,
motion of partial rotation, on the shaft A, is given to the sleeve which
motion is transmitted through the gearing E and E² to the arm G so as to move
the outer eccentric Cround the inner eccentric B more or less according to the
distance the collar I is moved along the sleeve. By moving the pins or projection in
collar D along from one end to the other of the slots one half revolution will be given

page_text: to the sleeve and thus the outer eccentric will be moved from its one extreme position
to the other.
The movement of the collar may be effected by means of a forked lever h engaging
in the groove in the periphery of the collar D and operated by a screw k as shewn or
by any other convenient means.
In applying my Invention to the adjustment of the position of a crank pin with
respect to the shaft in connection therewith the crank pin may be fitted to or formed
on the outer eccentric (or on a bracket or projection from a ring C² fitted to turn in
the groove in the periphery of the inner eccentric as shewn in Figure 3.
The crank pin K is attached to or formed on an overhanging bracket or hood L
from the ring C and the adjustment of the position of the said pin in order to alter
the throw of the crank is effected by turning the outer eccentric C or the ring C² as
the case may be on the inner eccentric B substantially in the manner described with
reference to Figures 1 and 2.
My Invention is applicable to cases generally where a ready means is required for
varying vibrating or reciprocating motions and it is specially applicable for working
slide or other valve of steam engines for varying the cut off, also to pumps for raising
water to varying heights or in various quantities when the power for working the
pump is uniform. It is also applicable to hydraulic brakes for cranes and other lifting
machines in which case the shaft A. may be connected to the gear of the crane by spur
or other suitable gearing, the strap of the external eccentric being connected to an
bydraulic force pump so that by adjusting the stroke of the pump the brake may be
applied with greater or less power and removed as required.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. In means for altering the throw of adjustable eccentrics or crank pins the com-
bination with a compound eccentric (i.e. two eccentrics fitted to turn one within the
other) of a sleeve fitted to turn on the shaft which carries the compound eccentric the
said sleeve being connected to one of the eccentrics of the said compound eccentric
so that by imparting rotation to the sleeve the positions of the two eccentrics with
respect to each other will be altered and the throw of the eccentric or crank be made
greater or less accordingly substantially as hereinbefore described.
2. The combination with the subject matter of the preceding claiming clause of
means for imparting partial rotation to the sleeve the said means consisting of a pin
or projection engaging in slots in the sleeve and in the shaft on which it is carried the
slots being so arranged that by sliding the pin or projection there along motion of partial
rotation will be given to the sleeve substantially as and for the purpose hereinbefore
described with reference to the accompanying drawings.
3. The general combination and arrangement of parts constituting means for altering
the throw of an adjustable eccentric substantially as herein before described and
illustrated by Figures 1 and 2 of the accompanying drawings.
4. The general combination and arrangement of parts constituting means for
altering the throw of an adjustable crank pin substantially as hereinbefore described.
and illustrated by Figure 3 of the accompanying drawings.
TIL: 09-1 1800
J. H. JOHNSON & Co.,
Agents.