IMPROVEMENTS IN STEAM ENGINES.”
Year: 1880

page_text: LETTERS PATENT to John Turnbull, junior, of Glasgow, in the County of
Lanark, North Britain, Engineer, for an Invention of "IMPROVEMENTS IN
STEAM ENGINES.”
PROVISIONAL SPECIFICATION left by the said John Turnbull at the Office
of the Commissioners of Patents on the 14th February 1880.
JOHN TURNBULL, junior, of Glasgow, in the County of Lanark, North Britain,
Engineer. "IMPROVEMENTS IN STEAM ENGINES."
This Invention has reference (first) to a now or improved arrangements of the
parts of borizontal steam engines, and especially in the parts thereof for guiding
the piston rods and carrying up or supporting the weight of these, and for working
the air and other pumps, and thus particularly suitable for saving the friction of
guides in the larger class of single or double cylinder horizontal engines; and
(second) to improvements upon and connected with the cut off gear for steam
engines described in the Specification of Letters Patent granted to the petitioner,
and dated 27th December 1878, No. 5287, for the purpose of making these
improvements specially applicable to marine engines, winding engines, locomotive
engines, and other engines in which the use of a governor may be dispensed
with.
And the nature and novelty of this Invention consists all as follows:-The first
part of the improvements relates to the construction and general arrangement of
horizontal engines, in which, instead of the usual sliding cross-head and guids, a
parallel motion has been employed at the inner or connecting rod end of the piston
rod, consisting of two vertical oscillating levers attached at their lower ends to a
short cross-head at the end of the piston-rod, and at the upper or fulcrum end or
rocking centre jointed to a pair of long horizontal radius bars fulcrumed at their
other ends to a standard over the cylinder. The lower members of this parallel
inotion are formed by double bell-crank or rocking levers outside the upper
oscillating levers fulcrumed on a rocking spindle in bush bearings secured to the
under side of the engine sole plate, and having their upper free ends jointed to the
outer ends of a cross centre passing through the upper vertical oscillating levers in
such a radial position over the piston rod as to guide its cross head in a parallel
line through between the vertical arms of the bell cranks; and when applied to

page_text: condensing engines the horizontal arms of these bell-crauks are made to work the
air pump or other pumps. By a minor improvement of the present Invention tho
air-pump rod of the said arrangement of bell cranks for working this is guided by
a simple parallel motion without the usual slide guides by connecting short vertical
bean links to a cross-head at the upper end of the pump rod, having the upper
ends of these links jointed to the horizontal arms of the bell cranks or rocking
levers forming part of the engine parallel motion, and their lower ends to reversely
ranged horizontal radial side bars rocking on a suitable centre or centres secured
over and on the opposite sides beyond the air pump, these radial bars being equal
in length to the horizontal arms of the bell cranks.
An important improvement of this Invention consists in extending the piston
rod of such horizontal engines out through the opposite end of the cylinder or
cylinders furthest from the crank, and duplicating or repeating the arrangement or
combination of links and rods forming the engine parallel motion described by
attaching a short cross head at the opposite or outer end of the piston rod to the
corresponding oscillating vertical levers of this second parallel motion, the long
horizontal radius bars jointed to the upper ends of these oscillating levers being
also jointed to the same centre as that of the first parallel motion on the opposito
side, in the case of a single cylinder engine, or to a fixed centre on a separate
standard over the second or outer cylinder when there are two or more cylinders
placed in line with a continuous piston rod extending right through the cylinders,
as for compound engines ranged in line in this manner. When the air pump is at
the outer end of these engines the second double bell-crank or rocking levers at
this outer end are also formed with horizontal arms connected to the pump rod or
plunger, either directly through a connecting rod or by means of a parallel motion
formed by beam levers and radius links, similar to those described as used for
guiding the air pump rod when at the opposite end of the engines.
The advantages of this improved general arrangement are, that the weight of
the piston rod and its attachments is supported or partially balanced, and the piston
rod is relieved from any upward thrust or pressure, the friction of the piston or
pistons in the cylinders being thus greatly reduced, and a minimum expenditure of
power incurred in overcoming the resistance and friction of the moving parts by
dispensing with the usual slide guides in these new arrangements of horizontal
engines.
December 27,
The second part or improvements of this Invention consists in the adaptation
and application to the steam cylinders of marine engines, winding engines, loco-
inotive or other engines, whether fitted with a governor or not, of the improved
arrangement of a simple sliding scroll cam on a single shaft driven by wheel
gearing at the same speed as the engine crank shaft to actuate cut-off grid-iron
valve or valves (direct or through single levers) mounted to slide at right angles on
the back of box slide valves fitted at each end of the steam valve chest with steam
and exhaust ports to each in the face plate of the cylinder, all without interfering
with their uniform action and cut-off by their eccentrics and link motion. One
arrangement as applicable to a marine engine would be substantially as shown and
described in reference to Figures 1, 2, and 3 of the Specification and Drawings of
tho petitioner's said former Patent, No. 5287,
except that the cylinder
or cylinders would be placed vertically instead of horizontally, and thero
being no governor ou the can spindle or shaft the scroll cam would be fitted with
a hand lever or with links led to such a lever (or to the governor when there was
one), so that when shifted the increased diameter of the scroll would cut off the
steam at any part of the stroke of the piston from either end of the cylinder and
slide valve, in which-ever position these may be, through their slides and spindle
connections, all to suit and correct the speed and power of the engine at any
moment; re-acting springs fitted on the cut-off valve spindles (or other equivalent)
and on the scroll cam would bring these parts back to their normal working
position when the hand or regulating lever was let go. In this vertical arrange-
1878,

page_text: ment for marine engine cylinders the weight of the slide valves and cross cut-off
valve mounted on them would preferably be carried up by a small steam piston
fitted on the upper end of the valve rod working in a cylinder on and open to the
upper end of the valve casing.
A somewhat different arrangement of the scroll cam and its fittings is required
to suit the valves of winding engines, which must work equally regular in reverse
directions at any moment, one simple construction of which consists in having a
train of three mitre wheels connecting the cam driving shaft with the actual cain
spindle or shafts. The two wheels on the former shaft run loose, and actuate the
one fixed on the latter always in the same direction, which-ever direction the
driving shaft may be turned by the engine shaft to which it is geared. Each of
the loose wheels have a stop or clutch cast on their adjacent ends with a clutch
box mounted by a groove and feather on the driving shaft between them, having
corresponding stops on each side to engage with the stops on the end of either
wheel, according as shifted from one side to the other by an edge groove and forked
lever connected by links and levers to the wiper shaft or hand gear, which shifts
the reversing link motion to suit the direction the engine is turning for the time
being back or forward. The stops are formed or placed on the opposite ends of the
clutch in such a relation to each other that while it is being shifted into the
ono wheel or the other it allows the cam spindle or shaft to stand or stop for half a
turn of the engine, or such other distance as is required to suit the slide valve for
running in the reverse or back direction; that is, the stops on the clutch and
reversing wheels are set to suit the reversing of the engine in the same manner as
is frequently done with engines having single excentrics loose on crank shafts
engaged and turned by a fixed stop on shaft when turned in the forward or back-
ward direction.
Although the improvements of this Invention have been described separately
under two heads for the purpose of distinguishing them, still it will be understood
and evident that they are all improvements upon the petitioner's said former
December 27,
Patent, No. 5287, 1878.
'That is, the improvements under the first head relating to the parallel motions
have reference only to horizontal steam engines of the kind to which the improve-
ments under the second head are shown and described as applied and connected in
the Specification of the petitioner's said former Patent; and the improvements
under the second part or head of the present Invention being already fully
described and claimed as applied to the said horizontal class of engines in the
Specification of the said former Patent, No. 5287,
and now only
under the present improvements applied as an extension and adaptation of
these improvements to marine engines, winding engines, locomotive engines, or
other such engines which may require to be reversed, or to which a governor may
not necessarily be applied, as is the case in the engines of the said former
Invention.
December 27,
1978,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Turnbull in the Great Seal Patent Office on the 13th August
1880.
JOHN TURNBULL, junior, of Glasgow, in the County of Lanark, North Britain,
Engineer. "IMPROVEMENTS IN STEAM ENGINES."
And
My said Invention has reference (first) to new or improved arrangements of the
parts of horizontal steam engines, and especially in the parts thereof for guiding
the piston rods and carrying up or supporting the weight of these, and for working
the air and other pumps, and thus particularly suitable for saving the friction of
guides in the larger class of single or double cylinder horizontal engines.
(second) to improvements upon and connected with the cut off gear for steam engines
of the kind described in the Specification of Letters Patent granted to me and
dated 27th December, 1878, No. 5287, for the purpose of making these improvements
specially applicable to marine engines, winding engines, locomotive engines, and
other engines, in which the use of a governor may be dispensed with.
And in order that the nature, novelty, and mode of performing my said Invention
may be properly understood, I shall now proceed to describe the several Figures on
the accompanying two Sheets of Drawings, which I have hereunto appended for
that purpose, the same reference letters indicating the same or like parts where
shown.
Referring to Sheet 1, Figure 1 is a longitudinal side elevation, and Figure 2 is a
transverse section taken near the line 1-1 in Figure 1, both of one arrangement
of horizontal compound double cylinder ongines Z, Z, Z, illustrative of one
modification or arrangement, or combination of the parts of the first improvements
of my Invention. Figure 3 is a longitudinal side elevation of a similar compound
engine embodying a slightly different modification or application and combination
of my said improvements.
Referring to Figures 1, 2, and 3, the first part of the improvements relates to
the construction and general arrangement of horizontal engines Z, Z, Z", in which
instead of the usual sliding cross head and guides a parallel motion has been
employed at the inner or connecting rod end A of the piston rod z, consisting of
two vertical oscillating lovers A', A¹, attached at their lower ends to the short
cross-head A at the end of the piston rod z of the engine Z, Z¹, Z", and at the
upper or fulcrum end or rocking contre A" jointed to a pair of long horizontal
radius bars a fulcrumed at their other ends at a¹, on a standard 2, over the
cylinder Z'. The lower members of this parallel motion are formed by the two
rocking levers B, B, outside the upper oscillating levers A¹, A', fulcrumed on a
rocking shaft B' in bush bearings secured on wall-boxes or beams 2" below the
engine solo plate Z, and having their upper free ends jointed to the outer ends of
a cross centre A2, passing through the upper vertical oscillating levers A', A¹, in
such a radial position over the piston rod as to guide its cross-head A in a
parallel line through between the vertical or rocking arms B, B, of the bell-crank
action B, B¹, B"; and the horizontal arm B₁ of this bell-crank action is made to
work the air pump, and it might be others pumps.
By a minor improvement of the present Invention, as shown in Figures 1 and 2,
the air pump rod 2³ of the said arrangement of rocking levers B, B', B¹¹, for working
this is guided by a simple parallel motion without the usual slide guides by con-
necting short vertical beam links b, b, to a cross-head 61 at the upper end of the
pump rod, having the upper ends of these vertical links b, b, jointed to the
horizontal arm B" of the rocking levers B, B, forming part of the engine parallel
motion, and their lower ends to radial side bars 6", 61, reversely ranged to the
armı B₁ rocking on a spindle or centre 63 secured over and on the opposite side of
1-

page_text: the air pump, these radial bars 6", 6", being equal in length to the horizontal
arm B of the rocking levers B, B', B¹¹.
An important improvement of this Invention consists in extending the piston
rod of such horizontal engines Z, Z, Z", out through the opposite end of the
cylinder Z', or as shewn in these Figures 1 and 3, through both the high and low
pressure cylinders Z, Z", and duplicating or repeating the arrangement or combi-
nation of levers and rods A, A¹, a, B, B¹, forming the engine parallel motion
described by attaching a short cross-head A at the opposite or outer end of the
piston rod to the corresponding oscillating vertical levers A', A', of this second
parallel motion, the long horizontal radius bars a, a, jointed to the upper ends A"
of these oscillating levers A', A', being also jointed to the same centre a as that of
the first parallel motion on the opposite side in the case of a single cylinder engine,
or to a fixed centre a' on a separate standard ¹ over the second or outer cylinder Z",
when there are two or more cylinders Z, Z", placed in line with a continuous
piston rod extending right through the cylinders, as for compound engines ranged
in line in this manner, as shown in these Figures. When the air pump 2 is fitted
at one side at the outer end of these engines Z, Z, Z", as shown in Figure 3, the
set of rocking levers B, B, B', of the second or end parallel motion at this outer end
has a horizontal arm B connected to the pump rod or plunger by means of a
parallel motion formed by the vertical beam levers b, bi, and radius links b¹¹, b²,
similar to those described as used for guiding the air-pump rod when fitted at
the other or connecting rod end of the engines Z, Z, Z", as described in reference
to and shown in Figures 1 and 2, but it might be by a connecting rod when the
cross-head is fitted in guides. The advantages of this general arrangement are that
the weight of the piston rods and its crosshead A, and rocking levers A', A", u,
are supported or partially balanced, and the piston rod is also relieved from any
upward thrust or pressure, the friction of the piston or pistons in the cylinders
Z, Z, being thus greatly reduced, and a minimum expenditure of power incurred
in overcoming the resistance and friction of the moving parts by dispensing with
the usual slide guides in these new arrangements of horizontal engines.
December 27,
1878.
Although the improvements of this Invention are described separately under two
heads for the purpose of distinguishing them, still it will be understood and evident
that they are all improvements upon my said former Patent, No. 5287,
That is, the improvements under the first head relating to the parallel motions
have reference only to horizontal steam engines of the kind to which the
improvements under the second head relating to the cut-off valves and actuating
mechanism are shown and described as applied and connected in the Specification
of my said former Patent, and are indicated in Figures 1 and 3 at d, d', over the
steam valve casing of the high pressure cylinders Z, Z". And these improvements
under the second part or head of the present Invention being already fully described
and claimed as applied to the said horizontal class of engines in the Specification of
my said former Patent, No. 5287,
December 27, need not here be further described.
The second part of the improvements of this Invention consists in the extension
and adaptation of the improvements of any said former Patent to the steam cylinders
of marine engines, winding engines, locomotives, or other engines, which may
require to be reversed, whither fitted with a governor or not, of the improved
arrangement of a sliding conoidal scroll cam or cams on a single shaft, driven by
wheel gearing from (and preferably at the same speed as) the engine crank shaft,
to actuate a cut-off grid-iron valve or valves (direct or through single levers for
each) mounted to slide at right angles on the back of the box slide valves fitted at
each end of the steam valve chest, with steam and exhaust ports to each in the face
plate of the cylinder; all without interfering with their uniform action and cut off
by their eccentrics and link motion, all substantially as hereinafter described in
reference to the several Figures on Sheet 2 of the accompanying Drawings.
1878,
Figures 4 and 5 are vertical sectional elevations at right angles to each other

page_text: (taken near the irregular lines 2
2 and 3 - 3, cach on the other) of the high
pressure cylinder Z, and its steam valve casing Z of a marine engine, as fitted with
and illustrative of one modification, or arrangement and combination of the
improvements under the second head or part of my Invention as applied to such
and like steam engines, which may or may not have a governor, and have to be
reversed in their action, or the direction of motion of their crank shaft. Figure 6
is a side elevation of another modification or combination of my improvements
under this second head of the Invention, as applied to and suitable for the valves a
and steam cylinders of a horizontal engine, such as that shown in Figures 1 to 3,
on Sheet 1, when used as a winding engine; or for other horizontal winding
engines, or for locomotive engines, or other such engines which have to be reversed,
and may or may not have a governor fitted to them; and Figures 7 and 8
show side and end views of the shifting clutch 1, 3, and arrangement of reversing
gearing x, x, x, therefor, to a large scale, as detached from Figure 6, to show the
construction more clearly, and here substituted in place of the wheels y', y', in
Figures 4 and 5.
Referring to Figures 4 and 5, Z is the steam cylinder, preferably cased and
secured by strong flanged brackets Z* at the lower end to the top of the strong
standards or side frames 73, much as usual in inverted vertical cylinder marine
engines; and Z is the steam valve casing with short steam ports p, p, leading to
the extreme ends of the cylinder Z, with exhaust ports 21, 22, on the inner side of
these, opening into one long common exhaust chamber and leading off branch Z",
over which ports short double chambered steam and exhaust slide valves A, A, aro
worked by one valve rod A' and link motion A", all so far much as usual. Each
valve A has fitted on the back a long cross or transverse reciprocating cut-off grid-
iron or plate valve a, and its rod a, and slide plates a², a³, a¹¹, directly actuated in
one direction by the re-acting piston and conoidal spring d¹, d, in the air dash
pot d, for each spindle a¹ and valve a, and positively by the bell-crank b, b¹, and
pushing rods c, c³, from the conoidal scroll cam C, mounted to slide by a groove and
feather (and collar groove, as will hereinafter be described) on the short horizontal
driving shafts, carried in bearing brackets 2', s, in a central recess of the steam
casing Z; and actuated by the mitre wheels y, y, from the vertical shaft y,
carried in bearing brackets y" at the upper and lower ends, and there driven direct
by mitre wheels from the crank shaft of the engine, not shown in the Drawings;
and all, so far as described, arranged and actuated substantially in the same manner
as specified in reference to and shown in Figures 1, 2, and 3 of my said former
Patent No. 5287,
December 27. except that the cylinder Z (or it might be cylinders,
when there are more than one in the engine) is set vertically instead of
horizontally, as in these Figures, having the said cut-off valvo gearing and fittings
accordingly ranged and turned at right angles with the cylinder. But as there is
no governor on the cam shaft (or conveniently possible in this class of marine
engines) the scroll cam C is fitted with hand gear consisting of a rocking spindle L
(carried in bearing brackets L¹ from the frame of the dash pots d, d,) and
arrangement of forked lever 1, taking into the collar groove of the scroll cam C,
actuated by a band lever and rod ",", (convenient to be actuated by the engine- 4
man, where he controls the ordinary valve link motion), which would shift the cam
out or in between the pushing rods c, cl, and c, c', of the cut-off valves a, a, and so
give any required opening of the valves, and cut-off of the steam, and regulate the
speed or power of the engine as desired; while the lever or rod could be fitted
with a holding screw and quadrant, or other equivalent, to fix the scroll cam C in 5
any working position it was set to, that is, when the engine is running the usual
forward direction, as indicated by the arrows on the driving shafts and gearing y', y',
When the engine has a governor, it could be made to control this to and
fro action of the cam C, and cut-off of the steam, by connecting the free end of a
reciprocating rod, actuated by the governor, to the slotted lever 12 of the rocking 5
and
1878,
4

page_text: spindle L, the governor pushing in or drawing out the scroll cam C, as the speed
of the governor rose or fell below the desired normal speed of the engine respectively
(or it might be vice versa), the pistons and conoidal springs d¹, d¹¹, of the dash
pots & acting in the reverse direction to the scroll cam C in keeping a steady action
of the parts and the rods c, c', up against the scroll cam. In either case, whether
worked by the hand gear 1, 1, 1, or governor and lover, the shifting out or in
of the scroll cam C towards its lesser or greater diameter respectively would give
any desired degree of cut-off of the steam at any part of the stroke of the piston
from either end of the cylinder and corresponding slide and cut-off valve A, a, A, a,
in which-ever position these may be, by their spindle slides and connections a¹, a³,
a³, all, all to suit and correct the speed and power of the engine at any moment.
In this arrangement of marine engines, Figures 4 and 5, where a single scroll
cam C only is used for controlling the cut-off when the engines are running in the
usual or forward direction, it is preferred to take this out of action and keep the
cut-off valves a, a, open when and while the engines are reversed or running in
the backward direction. This is effected by an arrangement of two bell cranks fƒ,
one f, f', close to the rod or spindle a¹ of each valve a, and having its vertical arm f
forked to embrace the rod a¹ and act on a collar or shoulder on it, and having the
two horizontal arms f, f¹, coupled by a pushing or drawing rod fll so as to be
worked simultaneously by a long hand lever f¹ on the spindle of the lower bell-
crank to pull out and keep the cut-off valves a, a, both full open, as stated, against
the power of the conoidal springs d in the dash pots d, d, while the engines are
being worked in the backward direction by the eccentrics and link motion of the
slide valves A, A; and for this purpose the hand lever f' may be fitted with a
spring, notched quadrant, or other equivalent for holding it in the open position
to which it is set, or completely out of gear when the cut-off valves a, a, are
being worked by their scroll cam C, and the engine is running in the forward
direction.
Instead of this arrangement of lovers f, f', ƒ", ƒ for opening the cut-off
valves a, a, while the engine is running backward, an extra scroll cam C could
be mounted on the shaft 2, coiled to act in the reverse direction when the shaft z
and engine are turned in the backward direction, and then drawn into action by
a lever arrangement, such as that shown at l, l. In this vertical arrangement for
marine engine cylinders the weight of the slide valves A, A, and rod A with the
cross cut-off valve a, a, mounted on them, would preferably be carried up by a small.
steam cylinder P fitted on the top of the casing Z¹ having its piston fixed on the
upper end of the valve rod A' working up through the lower end of the cylinder P
left open to the upper end of the steam and valve casing Z¹.
Referring to Figures 6 to 8 these show a somewhat different arrangement of the
scroll cam C and its fittings, and especially of the gearing for driving the shaft
required to suit the cut-off valves a, a, of winding engines, which have to work
equally regular in either or reverse directions at any moment under the control
of the engineman. This arrangement consists in having a set of three mitre
wheels a, a, a, connecting the cam driving shaft y with the actual cam shaft .
The two wheels x, x', on the former shaft y run loose, and actuate the one x" fixed
on the latter always in the same direction, as indicated by the arrows on it,
whether the driving shaft y may be turning in the forward or backward directions
with the engine shaft to which it is geared. Each of the loose wheels x, x', have
a projecting stop or clutch prong cast on their adjacent faces or ends with a
clutch box mounted by a sliding groove and feather on the driving shaft y
between them, baving corresponding projecting stops or clutches 23 on each side to
engage with the stops on the end of either wheel x or z³, according as it is
shifted from one side to the other by a centre groove fitted with a forked lever X
connected by a link or rod X' to a haud lever X" convenient for the engineman
to actuate them at any moment near the wiper shaft or hand gear, which shifts the
reversing link motion to suit the direction the engine is turning for the time being

page_text: back or forward. The gripping stops or prongs ³ and 2 are preferably formed or
placed on the opposite ends of the clutch box, and on the wheels x, x', in such
a relation to each other that while the clutch box is being shifted from the one
wheel into the other, it allows the cam spindle or shaft to stand or stop for half
a turn of the engine, or such other distance as is required to suit the slide valve for
running in the reverse or back direction, that is, the prongs ³, x², on the clutchi
reversing wheels are set to suit the reversing of the engine in the same manner as
is frequently done with engines having single eccentrics loose on crank shafts
engaged and turned by a fixed stop or prong on crank shaft when turned in the
forward or backward direction.
It will be evident that the roversing arrangement shown in Figures 7 and 8, is
equally applicable to and might be substituted for the bevil wheels y', y', in
Figures 4 and 5; and that those arrangements or mere modifications of them,
described in reference to and shown in Figures 4 to 8, for working the cut-off'
valve from a single shaft and scroll z, C, are equally applicable to the cylinders of
locomotive engines, or other engines which have to be frequently reversed, and
may or may not have governors attached to them.
Having thus described the nature of my said Invention, and the manner of
performing the same, I have to state that I do not confine myself to the precise
details herein described or delineated, but what I consider novel and original, and
therefore claim as the Invention secured to me by the herein before in part recited
Letters Patent is,―
First. The construction of horizontal engines with one or more cylinders, having
the outer or back end of their piston rod steadied and guided by a parallel
motion under the first head of iny improvements, consisting of a double set of 2
rocking levers A¹, A', and B, B, with radius bars a above and rocking shaft B'
below, made to work an air-pump or other pumps, when the engines are of the
condensing class, and either titted or not with my improved cut off valve gear, as
described under the second head of my improvements, all substantially as and for
the purposes herein described in reference to and shown in Figures 1 to 3, and 3
Figures 4 to 8 respectively of the accompanying Drawings, or any mere modifi-
cation thereof.
Second. In marine, winding, locomotive, or other steam engines which have to
be reversed, and may or may not have governors, the general arrangement and
combination of the parts and mechanism for actuating cut-off valves by a single 3
adjacent revolving shaft, and single or double scroll cam C, either geared direct
by mitre or bevil wheels from the crank shaft of the engine, as shown in Figures 4
and 5, or through the intermediate reversing gearing shown in Figure 6, and
particularly in Figures 7 and 8, all substantially as and for the purposes herein
described under the second head of my improvements, and shown in Figures 4 to 8,
on Sheet 2 of the accompanying Drawings, or any mere modification thereof.
Third. The general arrangement or combination of the parts or mechanism for
working the cut-off valves a on the back of slide valves A of a marine engine
cylinder, by a single or double scroll cam C on a short horizontal cam shaft z,
driven from the crank shaft of the engine, and fitted with hand lever arrangements 4
,,, for controlling the action of the valves a while the engine is running
forwards, and levers fff", f, for opening these valves while the engine is
working in the backward direction, controlled by its usual link motion and slide
valves A, all substantially as and for the purposes berein described in reference to
Figures 4 and 5 of the accompanying Drawings, or any mere modification thereof. 5
Fourth. The general arrangement or combination of the parts or mechanism for
working the cut-off valves on the back of slide valves A. of the cylinders of
winding engines, by a single scroll cam C on a short vertical shaft placed between
the valves, and driven from the crank shaft of the engine through the reversing
gearing and clutch motion, for controlling the action of the valves a while the 5
engine is running either in the forward or backward direction, all substantially as

page_text: described in reference to and shown in Figure 6, and in the detached detail views,
Figures 7 and 8 of the accompanying Drawings, or any mero modification
thereof.
In witness whereof, I, the said John Turnbull, junior, have hereunto set my
hand and seal, this Twelfth day of August, in the year of our Lord One
thousand eight hundred and eighty.
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
JOHN TURNBULL, JUN³. (L.S.)