IMPROVEMENTS IN COFFRWANG BAR
Year: 1872

page_text: LETTERS PATENT to William Haslett Mitchel, of Newry, in the
County of Armagh, Ireland, for the Invention of "IMPROVEMENTS IN
COFFRWANG BAR
".
PROVISIONAL SPECIFICATION left by the said William Haslett
Mitchel at the Office of the Commissioners of Patents, with his
Petition, on the 21st October 1872.
I, WILLIAM HASLETT MITCHEL, of Newry, in the County of Armagh,
Ireland, do hereby declare the nature of the said Invention for "In-
PROVEMENTS IN GOVERNORS FOR STEAM AND OTHER ENGINES AND MACHINERY," to
be as follows :—
as
My Invention relates to improvements in the class of governors known
chronometric governors," and differs from those previously employed,
chiefly in the greater simplicity and effectiveness of the means adopted.
In this class of governors as is well known, a part of the apparatus is
caused to move at a uniform speed, while another part is driven at the
variable speed of the engine to be regulated. Should any variation of
speed take place a differential motion is generated between the two parts
which by means of a screw or otherwise is made to actuate the throttle
valve or variable cut-off gear of the engine, as the case may be. The chief
advantage this kind of governors possesses over the ordinary ball governor

page_text: is that they begin to act instantaneously upon any variation of the engine
from its normal speed, and cease to act so soon as that speed is recovered,
whatever may then be their position or that of the valve, thereby
enabling the engine to run at its regular speed with or without a load,
and with more or less pressure of steam. Heretofore a rotatory pendulum
(either single or double) has been used as the regulator of the "chrono-
metric" part of the apparatus, and this pendulum has been kept in
rotation generally by means of a weight applied in various ways.
According to my present Invention I dispense with weights and other
independent means of giving motion to the regulating or "chrono-
metric" part of an engine governor, and I cause it to derive its motion in
a more direct manner from the engine to be regulated. I also supply
simple means whereby the governor even when running may be adjusted
to keep the engine at any desired speed within rather wide limits.
Finally, I arrange the details in a simple and inexpensive manner.
The essential feature of my Invention is the employment of two pairs
of friction surfaces, one pair acting to accelerate the speed of the
governor, and the other to retard such speed; the combined action of
these two forces or agents maintaining a practically uniform speed to
the governor.
I will now proceed to describe the mode in which I propose to carry
my Invention into practice. In the bracket or other part on which the
governor is mounted I fix a stud firmly, but so that its height may be
capable of adjustment by a screw acting at the end thereof, a set screw
being employed to hold the stud firmly in position when adjusted. On
this stud I form or firmly fix a friction plate or surface, and I mount
upon the stud a pinion which is capable of revolving freely thereon, and
on this pinion I form or fix another friction plate or surface. On this
stud is also mounted a sleeve or hollow axis, also capable of freely
revolving thereon, and on such sleeve or hollow axis is formed or fixed a
long pinion as also the "guards" in which the arms of the governor
balls work. These arms are jointed to lugs fixed on another friction
plate which is capable of revolving freely on the stud, and acts in con-
nection with the first mentioned friction plate as the retarding agent to
the governor. The links are attached at one end to the "guard," and
at the other to the arms of the governor balls in such manner that an
outward movement of the balls raises the sleeve or hollow axis on the
stud, but through a small space only. This sleeve or hollow axis is

page_text: connected with the friction plate to which the governor ball arms aro
attached so as to cause the whole to revolve rigidly together, and at the
same time admit of longitudinal motion to the sleeve or hollow axis.
Formed on or fixed to the long pinion on the sleeve or hollow axis is
5 another friction plate which acts in connection with the aforesaid friction
plate on the loose pinion as the accelerating agent to the governor. The
driving shaft of the governor has fixed thereon a pinion which takes into
and gives motion to the loose pinion on the fixed stud, and therefore
gives motion to the friction plate fixed on such loose pinion. The
driving shaft has formed thereon a screw or worm on which is mounted
a traversing nut carrying another pinion which gears with the long
pinion on the sleeve or hollow axis. I make the pinion on the driving
shaft larger in diameter than that gearing with it (preferably about one
fourth larger), and the other pinions I form of equal diameters with
each other, but these proportions may be varied.
The traversing nut is made by any suitable means to actuate the
throttle valve or variable cut-off, as is well understood.
By raising or lowering the fixed stud the governor may be adjusted to
keep the engine at any desired speed.
I would here remark that my Invention is capable of various modifi-
cations, such for instance as the employment of weights fixed to vertical
springs which are connected rigidly at each end to a frame by which
means as an increased speed of rotation is given to the weights, and they
are caused to fly outwards by centrifugal force; they operate to cause
one portion of the frame to slide on the fixed stud, and thereby bring the
retarding friction plates into use.
Another modification consists in dispensing with the hollow sleeve or
axis in which case I cause the stud or axis of the governor (which was
described as fixed in the first arrangement) to rotate with the governor,
and I dispense with the sleeve or hollow axis, and fix the long pinion
directly upon the revolving governor axis; and I fix one of the retarding
friction plates to such axis, and the other to the frame carrying the
governor.
In applying my Invention to other machinery than engines, in some
cases the pinions herein-before described may be dispensed with.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Haslett Mitchel in the Great Seal Patent
Office on the 21st April 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HASLETT MITCHEL, of Newry, in the County of Armagh, Ireland, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of October, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Haslett Mitchel, Her special
license that I, the said William Haslett Mitchel, my executors, adminis-
trators, and assigns, or such others as I, the said William Haslett
Mitchel, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN GOVERNORS FOR STEAM AND OTHER ENGINES AND MACHINERY,"
upon the condition (amongst others) that 1, the said William Haslett
Mitchel, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar mouths next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Haslett Mitchel, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:
My Invention relates to improvements in the class of governors
known as "chronometric governors," and differs from those previously
employed chiefly in the greater simplicity and effectiveness of the means
adopted. In this class of governors, as is well known, a part of the
apparatus is caused to move at a uniform speed, while another part is
driven at the variable speed of the engine to be regulated. Should any

page_text: variation of speed take place a differential motion is generated between
the two parts, which by means of a screw or otherwise is made to
actuate the throttle valve or variable cut-off gear of the engine, as the
case may be. The chief advantage this kind of governors possesses over
the ordinary ball governor is that they begin to act instantaneously
upon any variation of the engine from its normal speed, and cease to act
so soon as that speed is recovered, whatever may then be their position
or that of the valve, thereby enabling the engine to run at its regular
speed, with or without a load, and with more or less pressure of steam.
Heretofore a rotatory pendulum (either single or double) has been used
as the regulator of the "chronometric" part of the apparatus, and this
pendulum has been kept in rotation generally by means of a weight
applied in various ways.
According to my present Invention I dispense with weights and
other independent means of giving motion to the regulating or
"chronometric" part of an engine governor, and I cause it to derive
its motion in a more direct manner from the engine to be regulated.
I also supply simple means whereby the governor, even when running
may be adjusted to keep the engine at any desired speed within rather
wide limits. Finally, I arrange the details in a simple and inexpensive
manner.
The essential feature of my Invention is the employment of two pairs
of friction surfaces, one pair acting to accelerate the speed of the
governor, and the other to retard such speed, the combined action of
these two forces or agents maintaining a practically uniform speed to
the governor.
I will now proceed to describe the mode in which I propose to carry
my Invention into practice. In the bracket or other part on which the
governor is mounted I fix a stud firmly, but so that its height may be
capable of adjustment by a screw acting at the end thereof, a set screw.
being employed to hold the stud firmly in position when adjusted. On
this stud I form or firmly fix a friction plate or surface, and I mount
upon the stud a pinion which is capable of revolving freely thereon, and
on this pinion I form or fix another friction plate or surface. On this
stud is also mounted a sleeve or hollow axis also capable of freely
revolving thereon, and on such sleeve or hollow axis is formed or fixed
a long pinion, as also the "guards" in which the arms of the governor

page_text: balls work.
These arms are jointed to lugs fixed on another friction
plate which is capable of revolving freely on the stud, and acts in
connection with the first-mentioned friction plate as the retarding agent
of the governor. The links are attached at one end to the "guards,”
and at the other to the arms of the governor balls, in such manner that
an outward movement of the balls raises the sleeve or hollow axis on
the stud, but through a small space only. This sleeve or hollow axis is
connected with the friction plato to which the governor ball arms are
attached, so as to cause the whole to revolve rigidly together, and at the
same time admit of longitudinal motion to the sleeve or hollow axis.
Formed on or fixed to the long pinion on the sleeve or hollow axis is
another friction plate which acts in connection with the aforesaid
friction plate on the loose pinion as the accelerating agent to the
governor. The driving shaft of the governor has fixed thereon a pinion
which takes into and gives motion to the loose pinion on the fixed stud,
and therefore gives motion to the friction plate fixed on such loose
pinion. The driving shaft has formed thereon a screw or worm, on
which is mounted a traversing nut carrying another pinion which gears
with the long pinion on the sleeve or hollow axis. I make the pinion
on the driving shaft larger in diameter than that gearing with it|
(preferably from about one eighth to about one fourth larger), and the
other pinions I form of equal diameters with each other, but these pro-
portions may be varied.
The traversing nut is made by any suitable means to actuate the
throttle valve or variable cut-off, as is well understood.
By raising or lowering the fixed stud the governor may be adjusted to
keep the engine at any desired speed.
I would here remark that my Invention is capable of various modi
fications, such for instance, as the employment of weights fixed to
vertical springs which are connected rigidly at each end to a frame by
which means, as an increased speed of rotation is given to the weights,
and they are caused to fly outwards by centrifugal force they operate to
cause one portion of the frame to slide on the fixed stud, and thereby
bring the retarding friction plates into use.
Another modification consists in causing the stud or axis of the
governor (which was described as fixed in the first arrangement) to
rotate with the governor, and in this case I dispense with the sleeve or

page_text: hollow axis and fix the long pinion directly upon the revolving governor
axis, and I fix one of the retarding friction plates to such axis, and
the other to the frame carrying the governor.
In applying my Invention to other machinery than engines, in some
cases the pinions herein-before described may be dispensed with.
And in order that my said Invention may be more clearly understood
and readily carried into effect, I will proceed aided by the accompanying
Drawings more fully to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is an elevation, and Figure 2 is a plan of a governor
constructed according to my Invention.
Figure 3 is an elevation, and Figures 4 and 5 are detail views of an
arrangement of governor similar to the foregoing, but having weights
fixed to springs instead of employing the ordinary governor balls.
Figures 6 and 7 are elevations of other slightly modified forms of my
improved governors, and Figure 8 is a detail view of Figure 7.
In the various Figures of the Drawings similar parts are marked with
similar letters of reference.
a is a stud fixed firmly in the bracket or beam b, but so that its
height may be capable of adjustment by means of a screw a' acting
against the lower end thereof, a set screw a² being employed to hold the
stud a firmly in position when adjusted. On the stud a I form or
firmly fix a friction plate or surface c, and I mount upon the stud a
pinion d which is capable of revolving freely thereon, and on this
pinion I form or fix another friction plate or surface d'. On the stud a
is also mounted a sleeve or hollow axis e also capable of freely revolving
thereon, and on such sleeve or hollow axis is formed or fixed a long
pinion, as also the "guards" g in which the arms of the governor
balls work. These arms are pin jointed to lugs fixed on another
friction plate i which is capable of revolving freely on the stud a, and
acts in connection with the friction plate c, as the retarding agent to the
governor. The links are attached at one end to the "guards" g,
and at the other to the arms in such manner that an outward
movement of the balls h raises the sleeve or hollow axis e on the stud a,
but through a small space only. This sleeve or hollow axis e is by rods
or pins e passing through eyes or lugs connected with the friction

page_text: plate i, so as to cause the whole to revolve rigidly together, and at the
same time admit of longitudinal motion to the sleeve or hollow axis e.
Formed on or fixed to the long pinion ƒ is another friction plateƒ'
which acts in connection with the friction plate d' as the accelerating
agent to the governor. The driving shaft has fixed thereon a pinion j'
which takes into and gives motion to the loose pinion d, and therefore
gives motion to the friction plate d'. The driving shaft j of the
governor has formed thereon a screw or worm j, on which is mounted
a traversing nut & having another pinion & fixed thereto, which gears
with the long pinion f. I make the pinion j' larger in diameter than
the pinion d (preferably from about one eighth to about one fourth
larger), and the pinions and f I form of equal diameters with each
other, but these proportions may be varied.
It will be manifest that when at rest, the balls acting through the
links on the sleeve or hollow axis as a fulcrum, the upper retarding
friction plate i will be raised out of contact with the other retarding
friction plate c, and the whole weight of the balls and the parts
connected with them will then rest on the pair of accelerating friction
plates d'and. When the engine begins to move the friction generated
between these plates will set the governor balls also in motion, but as
the speed increases the balls will begin to move outward, the retarding
friction plate i will be drawn into contact with the retarding friction
plate c, an ever increasing proportion of the weight will be thrown upon
the latter, while the pressure between the accelerating pair is corre-
spondingly relieved until a speed is reached at which the accelerating
and retarding frictions balance one another. At this point a practically
uniform speed of revolution of the balls will be maintained, even though
that of the engine may vary.
The governor being adjusted to revolve at the normal speed of the
driving shaft j it is obvious that any variation of the latter from its normal
speed will cause a differential motion of the traversing nut k, which may
be made by any suitable means to actuate the throttle valve or variable
cut-off, as is well understood.
By raising or lowering the fixed stud a the governor may be adjusted
to keep the engine at any desired speed.
At Figures 3, 4, and 5, I have shown a governor slightly modified
from that shown at Figures 1 and 2, in which case instead of employing

page_text: balls has in the previous figures, weights * are employed which are
fixed to vertical springs ³; and such springs ³ are connected rigidly at
cach end to a frame or arm i*, g*, by which means as an increased
speed of rotation is given to the weights h*, and they are caused to fly
outwards, they operate to cause the part i* to slide on the fixed stud a
and thereby bring the retarding friction plates i, c, into use. Or instead
of springs links may be used to connect the weights with the upper and
lower parts of the frame, in which case the action of centrifugal
force may be resisted by a helical or other spring acting to draw the
weights towards the stud a.
At Figure 6 I have shown another modification of my Invention, in
which case I cause the stud or axis a (which was described as fixed in
the former arrangements) to rotate with the governor, and I fix the
long pinion f directly upon the stud or axis a, upon which is also
fixed the retarding friction plate i; whilst the other retarding friction
plate c is fixed to the frame, bracket, or beam 6 carrying the
governor.
At Figure 7 I have shown another modification of my Invention ; in
this case the parts are somewhat similarly arranged to those of the
governor shown at Figure 1, except that the stud or axis a is caused to
revolve, and the links are so connected to the arms h¹ that on an
increase of speed taking place, the upper retarding plate i will be
depressed and the stud or axis a will be raised, and with it the upper
accelerating friction plate f¹, the lower retarding friction plate c being
in this case fixed to the frame l.
Figure 8 is a sectional view of the accelerating friction plates and
parts adjacent of the governor shown at Figure 7, by which it will be
seen that the lower end of the axis a is received in a hole formed
in the stud a* without bottoming therein; whilst the pinion & rests on
a shoulder a' formed on the stud a* and revolves freely on said
stud a*, which can be raised or lowered by the screw a¹ to regulate the
speed of the governor.
In applying my Invention to other machinery than engines, in some
cases the pinions herein-before described may be dispensed with. For
example, it may be used to convert the irregular motion derived from a
treadle into a uniform motion, in which case the lower accelerating
friction plate may be fixed on the upper end of the driving shaft, the

page_text: lower end of the governor spindle revolving in a hole in said upper end
of the driving shaft. The upper accelerating friction plate may be
attached to the sleeve, as already described. The upper retarding
friction plate may be fixed on the upper end of the governor spindle and
the lower retarding friction plate to the framing or bracket.
I would here remark that it has been before proposed to cause the
motions of the governor balls to bring into action alternating pairs of
friction surfaces, but in such case no attempt was made to produce a
"chronometric" apparatus thereby, as the speed of the governor varied
with that of the engine; and I would further remark that it has before
been proposed to combine a "chronometric" part with a differential
motion of a similar character to that shown in the Drawings.
Having thus described the nature of my said Invention, and
various modes in which the same may be carried into effect, I would
have it understood that what I claim is, the employment as part of a
governor of a "chronometric" mechanical device which resists with con-
siderable energy any force tending to make it revolve slower or quicker
than its normal speed; such chronometric device consisting in the use
of two pairs of friction plates or surfaces, one pair acting to retard, and
the other to accelerate the revolution of the governor balls or weights,
the friction plates being connected with the said balls or weights in such
a manner that the outward motion, or tendency to motion of the latter,
diminishes the pressure between the accelerating pair of friction plates
and increases that between the retarding pair, while an inward motion
or tendency to motion of the balls or weights reverses this effect.
In witness whereof, I, the said William Haslett Mitchel, have
hereunto set my hand and seal, this Twelfth day of April, in
the year of our Lord One thousand eight hundred and seventy-