Improvements in or connected with Reciprocating Pumps or other Reciprocating Machines for Controlling or Regulating the Speed or Motion thereof.
Year: 1889

page_text: Date of Application, 16th July, 1889
Complete Specification Left, 14th Feb., 1890-Accepted, 15th Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in or connected with Reciprocating Pumps or other
Reciprocating Machines for Controlling or Regulating the Speed
or Motion thereof.
1 EDGAR CHARLES THRUPP of 67 Kensington Gardens Square in the County of
Middlesex Civil Engineer do hereby declare the nature of this Invention to be as
follows:
The object of my Invention is to provide means in connection with reciprocating
pumps or other reciprocating machines whereby the motion or variation of speed
during the stroke can be controlled or regulated as desired in such a manner for
With
instance that as applied to pumps the delivery thereof is made more uniform.
his object I connect the piston rod or parallel motion gear or beam of the pump or
other machine whose reciprocating motion is to be governed to one end of a rocking
bar whose other end is centred to a fixed point. This connection is effected by a con-
necting rod and a link the latter joining the end of the rocking bar to the end of the
connecting rod, the pin which joins the connecting rod to the link being guided in a
curved path. The end of the said rocking bar is also connected to a rotating crank or
fly wheel by means of a connecting rod or preferably by two connecting rods which
join one another on a motion block working in a straight line with suitable guides.
As the said crank or fly wheel rotates it controls the motion of the piston rod of the
pump or other reciprocating machine in such a manner that the speed is regulate t
throughout the stroke as desired the pin at the end of the first mentioned connecting
rod moving through a curved path which may be formed as a guide or which may be
defined by carrying the said pin or point of connection between the said connecting
rod and the aforesaid link from the rocking bar upon a beam or lever which opposite
ends are connected by rods or links to two fixed points so as to give the proper
movement of the ends of the connecting rod and link through the curved path
necessary to give the required regulated motion to the pump or other reciprocating
machine and control the variation of speed throughout the stroke.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.
COMPLETE SPECIFICATION.
Improvements in or connected with Reciprocating Pumps or other
Reciprocating Machines for Controlling or Regulating the Speed
or Motion thereof.
1 EDGAR CHARLES THRUPP of 67 Kensington Gardens Square in the County of
Middlesex Civil Engineer do hereby declare the nature of this Invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
The object of my Invention is to provide a mode of connecting a reciprocating pump
or other reciprocating machine to the crank of a fly wheel shaft or other shaft which
is made to rotate at a uniform or approximately uniform rate in such a manner that
the speed of the piston or ram of the pump or other reciprocating machine during the
stroke is rendered more unifo:m than it would be if the connection were made with
the ordinary crank and connecting rod alone.
t
It is well known that in ordinary rotative engines, having the common connecting-
rod, the maximum speed of the piston occurs only at or near the middle of the
stroke and that it exceeds the mean piston speed by about 57 per cent., and also that

page_text: the periods of time occupied by the piston in travelling through each half of the
stroke are different and that these periods differ from the period of time occupied by
one quarter of a revolution of the crank shaft; whereas with connecting gear arranged
according to this Invention, the maximum speed of the piston need not exceed the
* mean piston speed by more than 24 per cent. and each half of the stroke may be made
to occupy the same or very nearly the same period of time as that occupied by the
crank shaft in turning through one quarter of a revolution.
To accomplish these results, I connect the piston rod or parallel motion gear or
beam or other similarly reciprocating part of the pumping engine or other machine, whole
reciprocating motion is to be governed, to one end of a rocking-bar, the other end of
which is centred at a fixed point. This connection is effected by a connecting rod and
a link, the latter joining the end of the rocking bar to the end of the connecting rod,
the point of attachment of the connecting rod to the link being constrained to move in
a curved path. The said rocking bar is also connected to a rotating crank or fly-
wheel by means of two connecting-rods which join one another on a motion-block or
cross-head, guided in a straight line by suitable guides-As the said crank or fly
wheel rotates, it controls the oscillations of the said rocking-bar which in turn governs
the reciprocating motion according to the path in which the before mentioned point of
attachment of the connecting rod to the link is constrained to move by its guiding
mechanism.
In order to reduce the maximum speed of the piston during the stroke it is
essential that the said point of attachment should approach the pivotted end of the
rocking bar during the first half of the stroke and recede from it during the second
half of the stroke and to secure uniform motion in the reciprocating parts during the
middle part of the stroke and also to accomplish each half of the stroke in the same
space of time as that occupied by one quarter of a revolution of the crank shaft it is
necessary that the path of the aforesaid point of attachment should be a reverse curve
as hereinafter explained.
The pin at the said point of attachment is compelled to travel along this curve by
being carried on a moving beam whose ends are attached to two rocking bars of
unequal length which oscillate about fixed centres.
In order that my said Invention may be clearly understood I shall now proceed
to describe with reference to the accompanying drawings an arrangement of the
same as applied to a pump from which its analogous applications will be likewise
readily understood.
1 is
Figure 1 represents a side elevation of the mechanism omitting the framework and
details not necessary to make the description clear. Figure 2 is a part end elevation
and Figure 3 a part plan of apparatus constructed according to my Invention.
the crank shaft 2 is the crank pin and 3 is a connecting rod attached to the crank
pin and to the sliding crosshead which travels along the guides 5. A rod 6
connects the sliding crosshead 4 to the end 7 of the rocking bar S which rocking bar
oscillates about the fixed centre 9. The link 10 connects the rocking bar 8 to the
beam 11 at the pin joint or crosshead 12 which is fixed to the beam 11 the beam
being carried at its ends 13 and 14 by two rocking bars 15 and 16 which oscillate
respectively about the fixed bearings 17 and 18. The connecting rod 19 is also
attached at one end to the pin joint or crosshead 12 and at its other end to the
sliding crosshead 20 which travels along the guides 21 and is fixed to the piston
rod 22 of the pump, 23 being the piston of the pump which is presumed to be
worked by a direct acting stenui cylinder whose piston is secured upon a continuation
of the pump piston rod.
In Figures 2 and 3 a convenient mode is shown of arranging some of the parts in
duplicate so as to avoid cross binding at the joints. The rocking bars 15 and 16 are
forked out and secured to long shafts 17 and 18 in order to prevent lateral movement
in the beam 11.
In applying the mechanism to a beam engine the crosshead 20 may be fixed to the
beam or may form part of the parallel motion gear, or the connecting rod 19 may be
linked on to any suitable part which is required to reciprocate with a regulated

page_text: motion of the kind herein before described as resulting from the application of my
Invention.
The manner in which the mechanism operates will be understood by referring to
Figure 1 and assuming the crank shaft 1 to be rotating at a uniform speed. It is
obvious that the angle through which the bar 8 moves in any given time is absolutely
controlled by the motion of the crank shaft and that by compelling the pin 12 to travel
in the path indicated by the thick curved dotted line a, b in Figure 11 obtain a
variable leverage about the pivot bearing 9 modified by the varying angle between
the bar S and the link 10.
It will be found that this path can be defined by adjusting the positions of the
centres 17 and 18 so that the crosshead 20 accelerates in speed at the beginning of
the stroke much faster than the crosshead 4, and attains its maximum speed in less
than one fourth of the stroke, retains that speed nearly or quite uniform through the
middle half of the stroke or more, and slackens down to nil during the last
quarter.
It is not necessary that the stroke of the crosshead 20 should be exactly equal in
length to that of the crosshead 4 or, that the link 10 should be attached to the same
point on the bar 8 as the connecting rod 6.
The results are best obtained by making the angle between the lines in which the
blocks 20 and 4 travel such that the sine of half this angle shall be equal to half the
length of the link 10 divided by the length of the bar 8.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is.
In reciprocating pumps or other reciprocating machines connecting the pump rod
or piston rod or parallel motion gear or beam or other convenient reciprocating parts
of the pump or other machine whose motion is to be governed by means of a connect-
ing rod and a link to a rocking bar whose oscillations are controlled by a crank upon
a rotating shaft or fly wheel shaft to which the said rocking bar is connected by two
connecting rods which meet on a motion block moving along a straight guide means
being also provided for guiding or constraining the travel of the point of connection
of the said link with the first mentioned connecting rod in a curved path substantially.
as herein before described and illustrated in the accompanying drawings.
Dated this Twelfth day of February 1890.
EDGAR C. THRUFF.