IMPROVEMENTS IN REGULATING MOTIVE POWER ENGINES
Year: 1854

page_text: LETTERS PATENT to Thomas Biggart, of Dalry, in the County of Ayr,
North Britain, Spinner, and Allan Loudon, of the same Place, Mechanic,
for the Invention of "IMPROVEMENTS IN REGULATING MOTIVE POWER
ENGINES."
Sealed the 27th March 1855, and dated the 19th October 1854.
PROVISIONAL SPECIFICATION left by the said Thomas Biggart and
Allan Loudon at the Office of the Commissioners of Patents, with
their Petition, on the 19th October 1854.
We, THOMAS BIGGART, of Dalry, in the County of Ayr, North Britain,
Cotton Spinner, and ALLAN LOUDON, of the same Place, Mechanic, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN REGULATING
MOTIVE POWER ENGINES" to be as follows:-
This Invention relates to mechanism to be employed in connection with
the ordinary ball or other similar governor of motive power engines, for the
purpose of securing a regular and uniform rate of working, and consists in
connecting the lever of the throttle valve with a rack in gear with a pinion.
which is made to turn in either direction, and so open or shut the throttle
valve when the speed varies from the regular rate. The pinion is made in

page_text: one piece with, or is fast on, the same spindle as a wheel or pair of wheels,
with two sets of ratchet teeth, set in opposite directions upon their peripheries;
or instead of this arrangement, the ratchet wheel may be fixed directly on the
spindle or the throttle valve, the bevil wheel and rack being dispensed with.
The ratchet wheel is encompassed by a frame, to which a uniform reciprocatory
movement is given by suitably connecting it with any moving part of the
engine, and this frame carries two catches or palls, which are each arranged
to act on one of the sets of ratchet teeth. The reciprocating frame is so
connected with the ball or other governor .employed that the action of the
latter may shift it laterally without interfering with its reciprocating motion;
the parts are so arranged, that when the engine is running at its prescribed
rate, the reciprocating frame will be in its central position; and when it is in
this position, neither of the palls will be in gear with the ratchet teeth. If,
however, the rate of the engine changes, the governor will shift the recipro-
cating frame to one side, so as to put one of the palls in gear with the ratchet
teeth, and the motion of the frame will turn the ratchet wheel and pinion
until the throttle valve is so far acted upon as to bring the engine back to the
prescribed rate, by which time the governor will have shifted the reciprocating
frame back to its central position, and the pall will cease acting on the ratchet
teeth. It follows, with these arrangements, that the return of the governor to
its normal position will not, as in the ordinary arrangement, shift back the
throttle valve to the position it was in before the change took place; the two
sets of ratchet teeth only reach in either direction to a sufficient extent to
shift the throttle valve to the positions in which it is either full open or quite
shut, so that if from any cause the engine continues to act on the reciprocating
frame after either of these points have been attained, this frame will move
without acting upon or straining the connections.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Biggart and Allan Loudon in the Great Seal Patent
Office on the 17th April 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
BIGGART, of Dabry, in the County of Ayr, North Britain, Spinner, and ALLAN
LOUDON, of the same Place, Mechanic, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Thomas Biggart and Allan Loudon, Her special license that we, the
said Thomas Biggart and Allan Loudon, our executors, administrators, and
assigns, or such others as we, the said Thomas Biggart and Allan Loudon,
our executors, administrators, or 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 Chanuel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN REGULATING
MOTIVE POWER ENGINES," upon the condition (amongst others) that we, the said
Thomas Biggart and Allan Loudon, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, 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 months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that we, the said Thomas Biggart and Allan Loudon,
do hereby declare the nature of our said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
Our said Invention relates to mechanism to be employed in connection with
the ordinary ball or other similar governor of motive power engines, for the
purpose of securing a regular and uniform rate of working, and consists in
connecting the lever of the throttle valve or steam-current regulator with a
rack in gear with a pinion, which is made to turn in either direction, and so
open or shut the throttle valve when the speed of the engine varies from the
regular rate.
The pinion is made in one piece with, or is fast on, the same
spindle as a wheel or pair of wheels, with two sets of ratchet teeth, set in
opposite directions upon their peripheries; or instead of this arrangement, the
ratchet wheel may be fixed directly on the spindle of the throttle valve,
the pinion and rack being dispensed with. The ratchet wheel is encompassed
by a frame, to which a uniform reciprocatory movement is given by suitably
connecting it with any moving part of the engine, and this frame carries
two catches or palls, which are each arranged to act on one of the sets of

page_text: ratchet teeth. The reciprocating frame is so connected with the ball or other
governor employed, that the action of the latter may shift it latterally without
interfering with its reciprocating motion; the parts are so arranged, that
when the engine is running at its prescribed rate, the reciprocating frame will
be in its central position; and when it is in this position, neither of the palls
will be in gear with the ratchet teeth. If, however, the rate of the engine
changes, the governor will shift the reciprocating frame to one side, so as to
put one of the palls in gear with the ratchet teeth, and the motion of the
frame will turn the ratchet wheel and pinion until the throttle valve is so far
acted upon as to bring the engine back to the prescribed rate, by which time
the governor will have shifted the reciprocating frame back to its central
position, and the pall will cease acting on the ratchet teeth. It follows, with
these arrangements, that the return of the governor to its normal position will
not, as in the ordinary arrangement, shift back the throttle valve to the
position it was in before the change took place. The two sets of ratchet
teeth only reach in either direction to a sufficient extent to shift the throttle
valve to the positions in which it is either full open or quite shut, so that if
from any cause the engine continues to act on the reciprocating frame after
either of these points has been attained, this frame will move without acting
upon or straining the connections.
And in order that our said Invention may be properly understood, we shall
now proceed to describe the explanatory Figures on the Sheet of Drawings
hereunto attached.
Figure 1 on the Sheet of Drawings is a front elevation of one modification
of our improved apparatus, to be applied to motive power engines in connec-
tion with the ordinary ball or similar governors; and Figure 2 is an edge or
side elevation, corresponding to Figure 1. The details of the apparatus are
carried in a light frame, consisting of two cast-iron standards A, tied together
by cross rods B. This framing is formed with centres for a horizontal spindle
C, upon which are fixed a pair of whicels or discs D, formed with ratchet teeth
upon the greater portion of their circumferences, the teeth on the two wheels
being inclined in opposite directions. These ratchet wheels are acted upon by
two weighted palls or catches E, carried by an open frame F. This frame F
is jointed to a rod G, which is connected to any reciprocating part of the
steam engine, and transmits a reciprocating motion to the frame F in a vertical
direction; and the frame is formed with projections II, above which work inside
a segmental guide I, screwed by a bracket to the frame A. A rod J is jointed
to the frame F at any convenient point, by preference near the level of the

page_text: spindle C, and this rod is jointed to the end of a lever K, fast on a rocking
shaft L, through which the action of the ball or other ordinary governor is
transmitted. The connections are so arranged, that when the engine is going
at its prescribed rate, the frame F will be in such a position as to keep the
two palls E clear of the ratchet wheels D, and these ratchet wheels will not be
affected by the vertical reciprocation of the frame F. If the speed of the
engine rises or falls, however, the lever K will shift the frame F to one side
or the other, so as to bring one of the palls into gear with the ratchet wheels
D, when the reciprocating motion of the frame will cause these wheels to
turn as long as the pall is in gear with them. The motion of the wheels D,
induced in the manner just described, is communicated to the throttle valve
connections by means of a pinion fast upon the spindle C of the wheels D, and
indicated in dotted lines at M. This pinion M is in gear with an intermediate
pinion N, carried loose on a bracket stud pin bolted to the standard A. In
the special arrangement, represented in the Drawings, this intermediate pinion
is merely requisite to reverse the motion to suit the other parts of the appa-
ratus, and it may be dispensed with if the other details are suitably modified.
The pinion N is in gear with a rack O, formed on the upper end of a rod P,
which works vertically in a guide Q, cast or fixed upon the framing, being
made to move up or down, accordingly as the ratchet wheels D move in one
direction or the other. Lower down, a rack R is formed on one side of the
rod P, and in gear with this rack is a pinion S, carried loosely on a pin at the
upper end of a rod T, which passes down, and is connected to the lever U of
the throttle valve. The pinion S is likewise in gear with a rack formed on
a rod V in guides W, cast or fixed on the standard, and to the lower end of the
rod V is jointed a link X, which connects it to a lever Y, fast on the shaft L.
This arrangement of racks, acting upon a pinion on the rod which shifts the
valve lever, is adopted in order to combine the rapid action of the ordinary
governor with the permanent action of the ratchet wheels and reciprocating
frame. If the rate of the engine varies, the ball or other governor will turn the
shaft L, and actuate both the levers Y and K. The lever Y at once shifts
the rod V, which causes the pinion S to roll up or down the, as yet, stationary
rack R, and so open or close the valve by means of the rod T. When the
engine returns to its proper rate, the lever Y returns to its former position,
and it would make the valve also return to its former position, were not the
rack R in the meantime to descend by the action of the ratchet wheels D and
the reciprocating frame F, which frame has been put into gear with the
ratchet wheels by the lever K. After the engine resumes its proper rate,

page_text: the valve stops at the point to which it has been worked by the ratchet wheels
and reciprocating frame, and this point may either be a greater or less distance
from its original position than that to which it is shifted in the first instance
by the lever Y. When the engine is brought back to its proper rate, the
levers K and Y assume the positions represented in the Drawings, and the
frame is so situated as to keep both the palls E clear of the ratchet wheels
D. The amount of play between the points of the palls E can be regulated
with the greatest nicety by means of the guide plates Z, in openings in which
projections on the palls are made to fall. These guide plates Z can be
adjusted by means of screws a, so as to allow the palls to fall more or less
near to the ratchet wheels, that is to say, so that a less or greater lateral
movement of the frame F will be requisite to make them act on the ratchet
wheels. The ratchet wheels are not made with teeth completely round their
peripheries, but there is on each a blank space, as at b, which is so situated
that the wheels D will not be urged round after the valve has been fully
opened or fully closed, so that if after the valve is so shut or opened, the pall
from any cause remains in gear with the ratchet wheels, and the reciprocating
motion goes on, none of the parts of the apparatus will thereby be strained or
injured. A friction piece c is made to press on the face of one of the wheels
D by the action of a spring d, fixed to the top tie rod B, by which means the
wheels D are prevented from being jerked or turned round too far, or other-
wise improperly shifted.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried
into effect, we may observe, in conclusion, that we do not confine or restrict
ourselves to the precise details or arrangements which we have had occasion
to describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of our Invention; but what we
consider to be novel and original, and therefore claim as the Invention secured
to us by the herein-before in part recited Letters Patent, is,
First, the general arrangement and construction of machinery, apparatus,
or means to be applied to motive power engines, for the purpose of regulating
their motion, as herein-before described.
Second, the application and use, in connection with the ordinary ball or
other governors of motive power engines, of a constantly reciprocating frame,
carrying a pair of palls or catches, and arranged to act upon a ratchet wheel
connected to the throttle valve, in the manner herein-before described.
Third, the system or mode of regulating motive power engines by the agency

page_text: of a constant reciprocator or traverser, in connection with the ordinary ball or.
other governor, contrived to shift the regulating valve, and leave it in its
altered position, for the purpose and in the manner herein-before described.
In witness whereof, we, the said Thomas Biggart and Allan Loudon,
have hereunto set our hands and seals, this Sixteenth day of April,
in the year of our Lord One thousand eight hundred and fifty-five.
THOMAS BIGGART. (L.S.)
ALLAN LOUDON.
(L.S.)