IMPROVE- MENTS IN SLIDE GEAR AND SLIDES FOR STEAM AND OTHER FLUID PRESSURE ENGINES
Year: 1877

page_text: LETTERS PATENT to Francisco de Camargo Pinto, of No. 2, Wallington Place,
Kennington Road, in the County of Surrey, for the Invention of "IMPROVE-
MENTS IN SLIDE GEAR AND SLIDES FOR STEAM AND OTHER FLUID PRESSURE
ENGINES."
Scaled the 11th May 1877, and dated the 8th March 1877.
PROVISIONAL SPECIFICATION left by the said Francisco de Camargo Pinto
at the Office of the Commissioners of Patents on the Sth March 1877.
FRANCISCO DE CAMARGO PINTO, of No. 2, Wallington Place, Kennington Road,
in the County of Surrey. "IMPROVEMENTS IN SLIDE GEAR AND SLIDES FOR
STEAM AND OTHER FLUID PRESSURE ENGINES."
My Invention relates to the gear employed for communicating movement to the
slides of steam and other fluid pressure engines so as to work the engines more or
less expansively or to stop or reverse their movement, and to the slides for alterna-
ting the admission and emission of the steam or working fluid. In describing the
nature of my improvements 1 will suppose them to be applied to a steam engine. I
joint the eccentric rod to a pin on a circularly slotted lever which works on a
tubular shaft or trunnion. Through this trunnion I pass a spindle which has on it
a toothed pinion; the said spindle being turned in either direction, as required, by
the hand gear of the engine which may be of any known kind. The pinion gears
with a rack fixed on a block that is fitted to slide in the slot of the lever, and the
said block is connected by a connecting rod to the slide of the engine or to a lever
or rod for working the slide. The slot in the aforesaid lever is cut in the form of a
circular arc struck from the farther joint of the slide connecting rod when it is at
mid stroke. As the eccentric revolves it causes the lever to oscillate on its trunnion.
If the sliding block be in the middle of the slot in the lever immediately over the
trunnion, then this point, having no motion, the slide remains at rest; but if by
means of the pinion and rack the sliding block be shifted along the slot to the
one side of the trunnion, then the slide receives a reciprocating movement timed
for the motion of the engine in the one direction, and if the block be shifted to the
other side of the trunnion the slide receives movement timed for the motion of the
engine in the opposite direction. Also the stroke of the slide is increased or
[Price 6d1

page_text: diminished by moving the block to a greater or less distance from the trunnion
either way. When this link motion is applied to a double or compound engine I
prefer to joint the eccentric rod of the one engine to the slide of its slotted lever,
opposite to that at which the eccentric rod of the other engine is jointed to its
slotted lever, and I thus get the advantage of having the moving parts connected
to the link motion in balance, or nearly so.
The link motion described above may be applied to work a slide of any known
kind, or to a slide constructed according to my Invention in the manner which I
will now describe. I make the slide of rectangular form with cavities within it and
ports on its one face for induction and eduction, that face sliding over the ports of
the cylinder. The opposite face is made with a grummet or projecting facing
which fits against the cover of the slide jacket. This cover is made with a pro-
jecting rib all round its edge, and in this rib there is cut a groove which receives a
band of packing and a pressing bar. The edge of the slice jacket itself is made to
enter this groove, so that when the cover is put on the jacket a tight joint is formed
by the packing all round the lip of the jacket. The cover is secured to the jacket
by bolts and nuts or screws, and near the outer edge of the cover there are setting
screws which press on the bar that overlies the packing in the groove.
By means of these setting screws and tho bolts or screws which hold on the cover,
its position can be accurately adjusted so as to bear upon the slide with such pres-
sure as is required for making it work without leakage. In the middle of the cover
there is a slotted hole, through which projects a boss attached to the slide, and to
this boss is jointed the rod for working the slide. The boss is made of rectangular
form, fitting the sides of the slot in which it works, which serve to guide it, and
which, for that purpose, may be made adjustable. When the form of the engine is
wuch that the slide has to work on edge I prefer to provide for its support rollers
under its lower edge to diminish friction, and in order to provent these rollers from
getting out of their proper position in their travel, I provide each of them with
teeth at one or both ends, gearing loosely with racks formed on the edge of the
slide.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francisco de Camargo Pinto in the Great Seal Patent Office on
the 5th September 1877.
FRANCISCO DE CAMARGO PINTO, of No. 2, Wallington Place, Kennington Road,
in the County of Surrey. "IMPROVEMENTS IN SLIDE GEAR AND SLIDES FOR
STEAM AND OTHER FLUID PRESSURE ENGINES."
My Invention relates to the gear employed for communicating movement to the
slides of steam and other fluid pressure engines so as to work the engines more or
less expansively or to stop or reverse their movement, and to the slides for alterna-
ting the admission and emission of the steam or working fluid. In describing the
nature of my improvements I will suppose them to be applied to a steam engine.
I joint the eccentric rod to a pin on a circularly slotted lever which works on a
tubular shaft or trunnion. Through this trunnion I pass a spindle which has on it a
toothed pinion; the said spindle being turned in either direction as required by the
hand gear of the engine, which may be of any known kind. The pinion gears with
a rack fixed on a block that is fitted to slide in the slot of the lever, and the said
block is connected by a connecting rod to the slide of the engine or to a lever or
rod for working the slide. The slot in the aforesaid lever is cut in the form of a
circular are struck from the further joint of the slide connecting rod when it is at
mid stroke. As the eccentric revolves it causes the lever to oscillate on its trunnion.
If the sliding block be in the middle of the slot in the lever immediately over the
trunnion, then this point having no motion, the slide remains at rest, but if by means
of the piston and rack the sliding block be shifted along the slot to the one side of

page_text: the trunnion, then the slide receives a reciprocating movement timed for the motion
of the engine in the one direction, and if the block be shifted to the other side of
the trunnion the slide receives movement tined for the motion of the engine in the
opposite direction. Also the stroke of the slide is increased or diminished by
5 moving the block to a greater or less distance from the trunnion either way.
When this link motion is applied to a double or compound engine I prefer to joint
the eccentric rod of the one engine to the side of its slotted lever opposite to that at
which the eccentric rod of the other engine is jointed to its slotted lever, and I thus
get the advantage of having the moving parts connected to the link motion in
balance, or nearly so.
The link motion described above may be applied to work a slide of any known
kind or a slide constructed according to my Invention in the manner which I will
now describe. I make the slide of rectangular form with cavities within it, and
ports on its one face for induction and eduction, that fuce sliding over the ports of
the cylinder. The opposite face is made with a grummet or projecting facing which
fits against the cover of the slide jacket. This cover is inade with a projecting rib
all round its edge, and in this rib there is cut a groove which receives a band of
packing and a pressing bar. The edge of the slide jacket itself is made to enter
this groove, so that when the cover is put on the jacket a tight joint is formed by
the packing all round the lip of the jacket. The cover is secured to the jacket by
bolts and nuts or screws, and near the outer edge of the covor there are setting
screws which press on the bar that overlies the packing in the groove.
By means of these setting screws and the bolts or screws which hold on the cover,
its position can be accurately adjusted so as to bear upon the slide with such
pressure as is required for making it work without leakage. In the middle of the
cover there is a slotted hole, through which projects a boss attached to the slide,
and to this boss is jointed the rod for working the slide. The boss is made of
rectangular form, fitting the sides of the slot in which it works, which serve to guide
it, and which for that purpose may be made adjustable. When the form of the
engine is such that the slide has to work on edge I prefer to provide for its support
rollers under its lower edge to diminish friction, and in order to prevent theso
rollers from getting out of their proper position in their travel I provide each of
them with teeth at one or both ends gearing loosely with racks formed on the edge
of the slide.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents an elevation of the side of a steam engine having its slide
worked from the eccentric by a link motion according to my Invention; Fig. 2 is a
longitudinal section through the middle of the link apparatus and slide; Fig. 3
is a plan of the link apparatus; and Fig. 4 is a transverse section through the
slide.
A. is a tubular trunnion working in a bearing B on the framing of the engine;
this trunnion projects from or is fixed to the circularly slotted lever C, to which is
jointed the eccentric rod D, so that as the eccentric revolves the lever C is caused to
oscillate on the axis of its trunnion A. In the slot of the lever C is fitted to slide a
block E, having projecting from it a pin e, on which as a joint works one end of the
slide rod F. To the block E is fixed a rack G gearing with a pinion H fixed on a
spindle that passes through the trunnion A, so that it may be turned in either
direction. In Fig. 2 I have shewn a worm and worm wheel K. for that purpose,
but other means of turning the spindle may obviously be employed. When by
turning this spindle, and thereby moving the rack G and block E to the middle
position as shewn in Fig. 1, notwithstanding that the lever C may be caused by the
revolution of the eccentric to oscillate, the fulcrum of that lever remaining at rest,
the pin e, whose axis coincides therewith, remains also at rest, and consequently the
slide is stationary, and the engine will be stopped. If however by turning the
spindle the rack G and block E are caused to move to the one side, as for example
to the position indicated by the dotted lines E' in Fig. 1, then the slide receives a

page_text: reciprocating motion timed to the revolution of the engine shaft in the one direc-
tion. If the block E were moved to the opposite side of the trunnion, the slide
would receive reciprocating notion timed to the revolution of the engine shaft in
the opposite direction. By moving the block E to various positions short of its
extreme positions on either hand the stroke of the slide will be varied so as to give
various degrees of expansion for either direction of revolution. The slide rod F,
connected to the above described link motion, may be employed to work a slide of
ordinary construction. In the Drawings I have shewn it applied to work a slide
arranged according to my Invention as I will now describe. The slide L has
cavities and passages suited to the cylinder ports, and has on its back a grummet Z
to fit against the cover N of the slide jacket and a rectangular boss M, projecting
through a slot in the cover N, and working in adjustable guides m. The slide
rod F is jointed by a pin to the boss M, and when the slide is at half stroke, and
the link motion lever C is in its middle position, the centre of this pin is the centre
from which it struck the circular slot of the lever C. The slide jacket O is made
with a lip all round it which projects into a groove o formed in the cover N; in
this groove is inserted soft packing with a pressing bar on which bear set screws P.
Also the cover is made with a flange, by which it is secured with collar bolts Q to a
flange of the slide jacket. By means of these bolts the cover is adjusted so as to
bear with the desired degree of tightness against the grummet 2 of the slide and the
jointing of the cover to the jacket is made tight against leakage by the packing in
the groove o set up by the screws P. I prefer to place under the nuts of the bolts
Q pieces of steel slightly arched so as to give a little elasticity to the pressure of
the cover N against the slide L. When the engine cylinder is horizontal, as shown
in the Drawings, in order to support the weight of the slide, I apply at its under
edge rollers R, on which it travels, these rollers travelling along facing strips
formed on the interior of the slide jacket; and in order to prevent these rollers
from being displaced I provide teeth at their ends gearing with rack teeth on the
edge of the slide, or it may be on the side of the jacket, these teeth having a pitch
circle coinciding with the circumference of the roller.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
First. The use for working an engine slide of a link motion consisting of a lever
mounted on a stationary trunnion, and caused to oscillate thereon by the eccentric,
the said lever having a curved slot, in which is moved to either hand by means of a:
rack and pinion a block jointed to the slide connecting rod, the whole constructed
and operating substantially as and for the purposes herein set forth.
Second. The method, substantially as herein described, of adjusting the cover of
an engine slide jacket to fit the back of the slide, and at the same time tightening
against leakage the joint of the cover to the jacket.
Third. Working a slide arranged in the manner referred to in the preceding claim
by a connecting rod jointed directly to a boss of the slide projecting through a slot
in the cover of the slide jacket between adjustable guides, substantially as herein
described.
Fourth. Supporting the slide of a horizontal engine on rollers toothed at the
ends, substantially as and for the purposes herein set forth.
In witness whereof, I, the said Francisco de Camargo Pinto, have hereunto
set my hands and seal, this Twenty-first day of June, in the year of our
Lord One thousand eight hundred and seventy-seven.
FRANCISCO DE CAMARGO PINTO. (L.s.)