CERTAIN IMPROVEMENTS IN STEAK ENGINES
Year: 1855

page_text: LETTERS PATENT to Robert Broadbent, of Stalybridge, in the County of
Chester, Machine Maker, and Squire Farron and Benjamin Grundy,
both of Ashton, in the County of Lancaster, Engineers, for the Invention
of "CERTAIN IMPROVEMENTS IN STEAK ENGINES."
PROVISIONAL SPECIFICATION left by the said Robert Broadbent, Squire
Farron, and Benjamin Grundy at the Office of the Commissioners of
Patents, with their Petition, on the 7th May 1855.
We, ROBERT BROADBENT, of Stalybridge, in the County of Chester, Machine
Maker, and SQUIRE FARRON and BENJAMIN GRUNDY, both of Ashton, in the
County of Lancaster, Engineers, do hereby declare the nature of the said
Invention for "CERTAIN IMPROVEMENTS IN STEAM ENGINES" to be as follows:-
Our Invention consists in certain improved combinations of parts for
working the slide or other valves of steam engines. When our improvements
are applied to a stationary steam engine, the governor is connected to a double
clutch box sliding between two bevel pinions; these pinions are on the same
upright shaft as a third pinion, which is driven by a pinion on a horizontal
shaft; this shaft supports a wheel, which has a uniform motion given to it
from the fly wheel or other convenient shaft; and to this wheel is attached the

page_text: cam, that works the slide or other valve. Another cam for causing the valve
to cut off the steam is attached to a bush fixed on the horizontal shaft; this
bush is provided with key ways for guiding a sliding block, which is drawn
to and fro and made to revolve partly round the horizontal shaft by suitable
mechanism. When the speed of the engine is too great, the governor in
expanding draws the cam towards the centre of the horizontal shaft, thereby
limiting the throw of the steam valve; but when more steam is required, the
throw of the cam is increased, thereby admitting more steam. The action of
the sliding block not only increases or diminishes the length of stroke in the
valve, but it also varies the relative positions of the cams for admitting and
for cutting off the steam, thereby affording facility in regulating the expan-
sion. When our improvements are applied to locomotives or other engines
working without governors, the position of the cams for working the valve can
be regulated by hand.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Broadbent, Squire Farron, and Benjamin Grundy in
the Great Seal Patent Office on the 7th November 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ROBERT
BROADBENT, of Stalybridge, in the County of Chester, Machine Maker, and
SQUIRE FARRON and BENJAMIN GRUNDY, both of Ashton, in the County of
Lancaster, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of May, in the year of our Lord One
thousand eight hundred and fifty-five, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Robert Broadbent, Squire Farron, and Benjamin Grundy, IIer special license
that we, the said Robert Broadbent, Squire Farron, and Benjamin Grundy,
our executors, administrators, and assigns, or such others as we, the said
Robert Broadbent, Squire Farron, and Benjamin Grundy, our 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 "CERTAIN IMPROVEMENTS IN STEAM ENGINES,"
upon the condition (amongst others) that we, the said Robert Broadbent,

page_text: Squire Farron, and Benjamin Grundy, by an instrument in writing under
our hands and seals, or under the hand and seal of either 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said Robert Broadbent, Squire Farron, and
Benjamin Grundy, 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 Specification thereof, reference being had
to the accompanying Drawing (that is to say):
-
The nature of our Invention consists in an improved combination of parts
applicable to steam engines, for regulating the admission of and for cutting off
the steam according to the velocity of the engine, so as to work the steam
more or less expansively. We have in the said Drawing given Figures for
showing how our Invention may be constructed, similar parts in each of the
views being marked with similar letters of reference.
b
Figures 1 and 2 are end elevations of a combination of machinery for
effecting the above objects; Figure 3 is a plan; and Figure 4, a sectional side
elevation of the same. Figure 5 is a view of part of a steam engine of the
ordinary construction, shewing the mode of applying our improvements. a, a,
are two standards and connecting plate, fixed to the bed plate or foundation of
the engine; 6 is a shaft supported in bearings in the standards a. This shaft
is made to revolve at the same velocity as the crank shaft of the engine,
shewn at c, in Figure 5, by the spur wheels d and e; the former of which is
fixed to the crank shaft, and the latter to the shaft 6; or the wheel o may be
driven in any other convenient manner. In the face of the wheel is a
slot f, see Figure 1, in which fits the cam 9 for giving motion to the slide
valve, by which steam is admitted to the cylinder of the steam engine. The
under side of the cam 9 bears upon the circumference of the bush h, loose
on the shaft b, one part of which is made flat, as shown at h', in Figure 1.
The object of this flattened part is to allow the cam g to approach the axis
of the wheel e when it is requisite to shorten the throw of the valve, the
cam being held against the circumference of the bush h by a double lever i,
jointed to the wheel e. One end of this lever is connected to the cam g, and
the other end is acted upon by the projection h³ on the bush h. The cam g
may be held in contact with the bush by a spring, thereby dispensing with
the lever i and projection h². To the bush h is fixed the cam j, for giving the
requisite motion to the valve for cutting off the steam. This cam imparts at all

page_text: times the same motion to the valve for cutting off, but the valve is operated
upon sooner or later, according to the quantity of steam required in the cylinder,
in the following manner:-Within the bush h are three or other suitable
number of keys, which fit in key ways in the sliding block k; this block is
⚫ moved lengthways of the shaft b, by means of the screws 1, which are connected
to a clip m, fitting in a circular groove of the sliding block; the screws / pass
through the worm wheels n, the bosses of which revolve in the standard a;
these worm wheels gear into the worms o, fixed on the shaft p; this shaft is
_furnished with two bevel pinions p'and p², both of which are loose on the shaft.
The pinions p' and p³ gear into the pinion g, which is connected by friction.
to the spur pinion g', driven by. the pinion r fixed on shaft b. The shaft p is
hollow part of its length, and contains the rod s, one end of which is jointed
to the elbow lever t, and the other end has a stud s¹, projecting through
a slot in the shaft p; this stud when the rods is moved endwise comes
in position for being acted upon by either one or the other of the pins pro-.
jecting from the bevel pinions p¹ or p². The short arm of the elbow levert is
connected by the link u to the governor, as shown in Figure 5. The sliding
motion of the block k is made to impart a partial rotary motion to the said
:block and to the bush h (either in excess, or the reverse of that imparted by
the shaft b), by means of the spiral groové b¹ cut in the shaft b, see Figure 4,
and the feather projecting from the block k. The cams g and j act on
bowls v, supported in the frame w, which slides in grooves in the standard a;
and to the frame w is jointed one end of the connecting rod a, the other end
of which gives motion to the levers y, one of which is connected to the valve
rod and valves in the ordinary manner, as shown in Figure 5.
shaft
In some cases the connecting rod x may be attached to the valve rod instead
of being connected to the lever on the rocking shaft, as shown. The segment i¹
is to hold the frame wafter it has been acted upon be either of the cams g
or j. The mode of operation is as follows:-The Drawing represents the
cams 7 and j and the other parts of the machinery in the positions they occupy
when the greatest quantity of steam is being admitted to the cylinder. The
is now stationary, because the stud s', projecting from the rod s, is
held by the governor in the central position, and consequently neither of the
pins projecting from the pinions p' and p² in revolving comes in contact with
the said stud. As soon as the velocity of the engine increases sufficiently to
expand the governor balls, the link is depressed, thereby bringing the elbow
levert into the position shewn in dotted lines in Figure 2; by this means the
stud is moved towards the pinion p³, the pin from which, as the pinion
revolves, comes against the stud s', which then carries the shaft p round in the

page_text: direction of the arrow in Figure 4; the worms o then give motion to the worm
wheels n, which act as nuts on the screws 7, and push the sliding block k in the
direction of the arrow in Figures 3 and 4. The spiral groove b', as the block.k
moves lengthwise of the shaft b, causes the said block to turn partly round,
and this rotary motion of the block is communicated to the bush by the
key ways, before mentioned; and as the cam j is attached to the bush h, it is
evident that the said cam is thus gradually moved from the cam g; conse-
quently the cam j acts sooner on the frame w, and cuts off the steam at an
earlier part of the stroke. The traverse of the slide valve for admitting the
steam remains, however, the same until the flat part of the bush h comes into
operation, that is to say, when the sliding block k has been turned round
about one quarter of a revolution by the action of the spiral groove b'.
As soon as the corner of the bush h, marked h*, comes against the cam g,
the incline h' comes in contact with the longer arm of the double lever i, and
if the block k continues its motion in the direction of the arrow,
the rotary
motion in advance of that imparted by the shaft 6 to the bush h causes the
flat surface h' to come under the cam g, this cam being kept in contact with
the flat surface by the lever i, acted upon by the inclined projection h³, before
referred to. When the flat surface h¹ of the bush h has arrived at a right
angle to the slot f in the wheel e, the cam 9 will have approached as near as
possible the centre of the shaft b; consequently the least motion will then be
imparted by it to the frame w, connecting rod x and valve rod, thus
admitting little or no steam to the cylinder. When the engine is performing
the desired number of revolutions, the governor balls hold the stud s' in the
central position between the two pinions p¹ and p³, as before stated, but when
the speed is reduced sufficiently to allow the balls of the governor to collapse,
the pin from the pinion p³ comes against the stud s', thereby giving motion to the
block k in the contrary direction to that indicated by the arrows in Figures 3
and 4, thereby causing the cam ; to approach the cam g, and gradually
to increase the admission of steam until the engine has regained its proper
velocity. The hand wheel p³ on the shaft p is for the attendant to regulate
the position of the cams 9 and j previous to starting the engine. When our
improvements are applied to locomotive or other engines working without
governors, the relative position of the cams 9 and j can be regulated by hand.
Having thus stated the nature of our Invention, and described the manner
of performing the same, we wish it to be understood that we do not limit
ourselves to the details herein set forth, as they may be varied without depart-
ing from the peculiar character of our Invention; and that what we do claim
is, the improved combination of machinery for working the slide valves of

page_text: steam engines in such wise that the amount of opening for the admission
of steam and the time of cutting off the steam may be regulated independently
of each other, as shewn and described.
In witness whereof, we, the said Robert Broadbent, Squire Farron, and
Benjamin Grundy, have hereunto set our hands and seals, this Fifth
day of November, Anno Domini One thousand eight hundred and
fifty-five
Witness,
H. B. BARLOW,
Manchester.
ROBT BROADBENT.
SQUIRE FARRON.
(L.S.)
(L.B.)
BENJAMIN GRUNDY. (L.B.)