IMPROVEMENTS IN SLIDE VALVES AND SLIDE GEAR FOR STEAM AND OTHER FLUID PRESSURE ENGINES
Year: 1882

page_text: LETTERS PATENT to Druitt Halpin of No. 9 Victoria Chambers Westminster
in the County of Middlesex, for an invention of "IMPROVEMENTS IN SLIDE
VALVES AND SLIDE GEAR FOR STEAM AND OTHER FLUID PRESSURE ENGINES."
PROVISIONAL SPECIFICATION left by the said Druitt Halpin at the Office
of the Commissioners of Patents on the 6th April 1882.
DRUITT HALPIN of No 9 Victoria Chambers Westminster in the County of
Middlesex "IMPROVEMENTS IN SLIDE VALVES AND SLIDE GEAR FOR STEAM AND
OTHER FLUID PRESSURE ENGINES
"
In the Specification to Letters Patent granted to me on the 3rd 'September 1878
No. 3495 I described a slide valve which while it is moved longitudinally to and
fro by a rod worked from an excentric in the usual way, is also caused to rock in
a plane parallel to the slide face by the action of another rod worked by expansion
gear, the face of the slide and the cylinder ports being so shaped that by the
rocking movement of the slide combined with its longitudinal reciprocation the
cut off can be varied while the exhaust remains constant. My present invention
relates to a construction and arrangement of slide valves and the gear for working
them whereby 1 am enabled to attain the same results in a more simple manner,
dispensing with one of the slide rods and its necessary packing. For this purpose
I give the one slide rod besides its to and fro reciprocation a partial revolution to
and fro round its axis so that the slide worked by it is caused to move both longi-
tudinally and transversely and its face as well as the edges of the ports being made
oblique, the cut off can be varied according to the greater or less extent of the
transverse movement while the exhaust depending as it does only on the longi-
tudinal movement, remains constant. The rod works in a swivel in the head by
which it is linked to the excentric, and it has projecting from it an arm which is
CD Ca

page_text: linked to a reciprocating lever worked by another eccentric or by a suitable system
of levers and rods from the main eccentric this giving the rod its rotary recipro-
cation. The extent of this reciprocation may be determined by a link motion that
can be adjusted by hand or varied by a governor or in other known ways adopted
for varying cut off and expansion. The slide may have a cylindrical face working
in a cylindrical hollow on the side of the main cylinder, this face and hollow being
struck from the axis of the slide rod as a centre. Or the slide and the facing on
which it works may be flat, the slide rod having on it arms with slotted holes or
other connections admitting of the rectilineal movement of the slide while these
arm's move in a circular path. Instead of a single slide governing ports near the
middle of the cylinder two short slides governing ports near the ends of the cylinder
may be worked in the same manner..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Druitt Halpin in the Great Seal Patent Office on the 6th October
1882.
DRUITT HALPIN of No 9 Victoria Chambers Westminster in the County of
Middlesex "IMPROVEMENTS IN SLIDE VALVES AND SLIDE GEAR FOR STEAM AND
OTHER FLUID PRESSURE ENGINES."
In the Specification to Letters Patent granted to me on the 3rd September 1878
No 3495 I described a slide valve which while it is moved longitudinally to aud
fro by a rod worked from an eccentric in the usual way, is also caused to rock in
a plane parallel to the slide face by the action of another rod worked by expansion
gear, the face of the slide and the cylinder ports being so shaped that by the
rocking movement of the slide combined with its longitudinal reciprocation the
cut off can be varied while the exhaust remains constant. My present invention
relates to a construction and arrangement of slide valves and the gear for working
them whereby I am enabled to attain the same results in a more simple manner,
dispensing with one of the slide rods and its necessary packing. For this purpose
I give the one slide rod besides its to and fro reciprocation a partial revolution to
and fro round its axis so that the slide worked by it is caused to move both
longitudinally and transversely and its face as well as the edges of the ports being
made oblique, the cut off can be varied according to the greater or less extent of
the transverse movement while the exhaust depending as it does only on the
constant longitudinal movement remains constant. The rod works in a swivel in
the head by which it is linked to the eccentric, and it has projecting from it an arm
which is linked to a reciprocating lever worked by another eccentric or by a
suitable system of levers and rods from the main eccentric, this giving the rod its
rotary reciprocation. The extent of this reciprocation may be determined by a
link motion that can be adjusted by hand or varied by a governor or in other
known ways adopted for varying cut off and expansion. The slide may have a
cylindrical face working in a cylindrical hollow on the side of the main cylinder,
this face and hollow being struck from the axis of the slide rod as a centre. Or
the slide and the facing on which it works may be flat, the slide rod having on it
arms with slotted holes or other connections admitting of the rectilineal movement
of the slide while these arms move in a circular path. Instead of a single slide
governing ports near the middle of the cylinder two short slides governing ports
Dear the ends of the cylinder may be worked in the same manner.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a side view of one form of engine provided with a slide valve and gear
for working it according to my invention, Fig. 2 is a plan of the engine, Figs. 3
to 9 inclusive shew to an enlarged scale parts in detail, that is to say :-Fig. 3 is a
horizontal and Fig. 4 a vertical section through the valve chest, Fig. 5 is a
transverse section through the crosshead guides, Fig. 6 is a front view of the
cylinder facing and its ports, Fig. 7 is a face view of the slide, Fig. 8 is an elevation
and Fig. 9 a longitudinal section of the connecting rod (provided at both ends with
ball and socket joints) for giving the slide its partial rotation, Fig. 14 is a part
longitudinal section shewing the swivel joint for the slide rod. In these figures A
is the framing of the engine, B the cylinder and C the crank shaft, on which there
the l

page_text: eccentric at E for giving the slide its partial rotation is linked to an arm F on a
rocking shaft I. This rocking shaft works in a bracket projecting down from the
framing and has fixed on it a curved arm G on which is fitted a slide H which is
linked by the connecting rod h to an arm L projecting laterally from an enlarged
part of the slide rod R. This enlarged part of the slide rod has its end turned
down so as to present several collars which are engaged in grooves of a head s put
on in halves, the enlarged part of the slide and the head work in a cylindrical
guide K projecting laterally from the framing. The slide H might be set by
hand at various distances from the fulcrum of the arm G so as to vary the cut off
as desired by varying the amount of partial rotation given to the slide. As shewn
in the drawings the slide H is linked to a levers worked by a centrifugal
governor S, so that according as the speed of the engine exceeds or falls short of
its normal rate the partial rotation of the slide is increased or diminished, and the
steam is cut off sooner or later in each stroke. The slide M and the facing N
along which it works are made with cylindrical surfaces struck from the axis of
the slide rod R, the slide being held free to advance as the surfaces wear between
two arms fixed on the slide rod as shewn in Figs. 3 and 4.
Figs. 10 to 13 inclusive shew an arrangement of slide with a flat face which is
made to move to and fro transversely by the partial rotation of the slide rod while
it is made to reciprocate longitudinally by the rectilineal movement of the slide
rod, and Figs. 15 to 18 inclusive shew how the amount of transverse movement
can be varied by tripping gear. Fig. 10 is a view of the cylinder facing N with
its ports, Fig. 11 shews the slide M partly in vertical section Fig. 12 shews
it partly in transverse section and Fig. 13 is a plan of the bracket arms O
which are fixed on the slide rod R. The slide M is in this case made with
a cylindrical boss embraced by a ring or buckle P which is free to slide to and fro
on the boss and is pivotted on a pin p which is carried by the arms and passes
freely through a hole formed in the body of the slide. Thus as the slide rod R
rocks with its arms O, the slide is moved transversely, along the cylinder facing
being free to slide within the buckle P. Fig. 15 is a side view of part of the
framing of an engine with tripping gear worked by a governor applied to determine
the partial rotation of the slide rod. Fig. 17 is a plan, Fig. 18 is a part transverse
section and Fig. 16 is a plan of the tripping lever worked by the governor. As in
the figures already referred to, A is part of the engine frame, and the crank shaft
carrying the eccentric D linked by the rod d to the swivel head k of the eccentric
rod, which works in the cylindrical guide K. The eccentric D is also connected by
a link 25 to one arm 24 of a bell crank lever, the other arm 23 of which is
connected by a rod 22 to a lever 21. This lever 21 to which are attached a pair of
trigger tappets 12 is pivotted on one arm 20 of a bell crank lever, the other arın 19
of which is connected to the engine governor in such manner that when the speed
of the engine exceeds its normal rate, the arm 20 is raised raising the tappets 12.
On the engine shaft C is fixed a cam 1 against which bear rollers 4 mounted on the
two arins of a fork lever 2. This lever is pivotted to the framing at 3 and has a
pin 5 connected to a disc 17 that works like a piston to and fro within a casing 16
alternately compressing a pair of helical springs 14 and 15 therein. The casing 16
is linked to a pin 6 on an arm 7 of a rocking shaft 11. Another arm 8 ou this
rocking shaft has at its end a spherical pin 9 which is linked by a connecting rod
such as is shewn by Figs. 8 and 9 to the arm L that projects laterally from the
slide rod R. On the upper part of the arm 7 are mounted two catch pawls 13
which are pressed upwards by springs (not shewn) as far as is permitted by stop
pins working in slotted holes in the pawls. By the reciprocation of the lever 2 the
springs in 16 are alternately compressed during parts of every revolution of the
engine shaft, and thereby a strain is put on the arm 7 alternately to right and to
left. So long as either of the pawl catches such as 13 is engaged by one of the
tappets 12 the arm 7 cannot move and consequently there is no partial turn of the
slide rod, but when by the movement of the lever 21 the tappet 12 becomes
disengaged from the catch 13, the precise movement of which disengagement is

page_text: determined by the governor raising more or less the lever arm 20, then the spring
of 16 which is then under compression rapidly moves the arm 7 causing the slide
rod to turn partly round and the slide to make its transverse stroke effecting the
cut off.
I have thus described two methods of varying the cut off, but it is to be under-
stood that other known methods may be applied for effecting sooner or later in
each stroke of the engine the partial turn of the slide rod whereby the slide receives
a transverse motion in combination with its rectilineal reciprocation as above set
forth. It will be seen that the middle cavity of the slide being of rectangular form
whilst the exterior edges that lap over the oblique ports are themselves oblique,
the transverse movement of the slide does not affect the period or area of exhaust
but affects only the period and amount of induction.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I would observe that cylindrical piston valves have
been arranged so as to turn partly round their axes while they reciprocated
rectilineally and therefore I make no claim in respect of such valves, but I claim
in respect of the slide valves and slide gear for steam and other fluid pressure
engines; Swivelling the slide rod, and causing it while it reciprocates rectilineally
to turn partly round its axis, so that the slide besides its longitudinal movement
receives also a transverse movement, substantially as and for the purposes herein
set forth.
In Witness whereof I the said Druitt Halpin have hereunto set my hand and
seal this fourth day of October in the year of our Lord One thousand
eight hundred and eighty two.
DRUITT HALPIN. (L.S.)