Note: Descriptions are shown in the official language in which they were submitted.
5775/5~75Z
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AN APPARATUS FOR DISSOLVI~IG A SOLIDIFIED MASS I~ O
This application is a division o~ Canadian
Patent Application Serial No. 517,483, filed September
4, l9g6.
This invention generally rela-tes to methods and
apparatus involving the oscillation of a fluid n ViVO; and
more particularly to a method for dissolving a solidified
mass in vivo including the step of oscillating an agitating
fluid in a localized body area to enhance the efficacy of a
dissolving agent therein, and to an apparatus especially well
suited to carry out that oscillation of the agitating fluid.
Solidified masses such as biliary duct stones and
gallstones may develop in hollow organs or ducts within
humans and animals and cause numerous health problems, as is
known to those skilled in the art. These deposits may be
removed from the body in various ways, including surgery or
1n v1vo dissolution of the concretion by solvents introduced
into the area of the body where the solidified masses are
located. The hazards and complications attributable to
surgery are well known, and it is desirable to avoid surgery
where suitable alternatives are available. Heretoore,
however, in vivo dissolution of cholesterol calculi has been
undertaken with only limited success for several reasons.
For example, the effectiveness of such an ln vivo
process depends, in part, on the thoroughness with which the
solvent fluids diffuse throughout the area of the body being
treated, and conventional methods and devices for introducing
therapeutic fluids into localized body areas normally do not
produce any more than a limited distribution of the fluid in
that body area. Also, cholesterol calculi dissolve at a
relatively slow rate when simply placed in contact with a
solvent fluid. The distribution and efficacy of a dissolving
agent in vivo may be enhanced by stirring or agitating that
agent in the area of the body being treated and this may be
done by repeatedly cycling or oscillating an agitating fluid
into and out from that bodv area.
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.
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During such a cycling or oscillating of an
agitating fluid, body fluids such as bile, and solid debris
may ~e withdrawn with the agitating fluid from the patientls
body. It is desirable that any withdrawn solids not be
cycled back into the body area since the purpose of the
whole procedure is to remove such solids from the patient's
body. It is also advantageous to prevent any withdrawn bile
from being cycled back into the body because bile usually
slows the rate at which the dissolving agent acts on the
solids in the body. To elaborate, cholesterol calculi and
other solidified mas~es that form inside the body are
usually more dense than bile, while the agents, such as
mono-octanoin and methyl-tertiary-butyl ether, used to
dissolve the solids are usually less dense than bile. As a
result, the solidified masses tend to sink in and the
dissolving agent tends to float on any bile in the body area
beiny treated, and thus the bile tends to separate the
solidified masses from the dissolving agent, reducing the
dissolving affect that agent has on the concretions. For
example, in one series of experiments in which mono-octanoin
was used ~o dissolve gallstones ln vivo, separating bile
withdrawn from the body so that the bile is not cycled back
into the body, increased by factors of between approximately
3 and 5 the rate at which the mono-octanoin dissolved the
gallstones to 50% of complete dissolution.
The present invention relates to an apparatus for
oscillating an agitating fluid into and out from a localized
body area, comprising: a pump for forcing the agitating
liquid into and drawing the agitating ~luid from the body
area in a continuous, cyclical manner; and fluid delivery
means for connecting the pump to the body area to conduct
the agitating fluid therebetween, and including (i) a
fluidtrap for collecting body fluid aspirated from the body
area, and including means for discharging body fluid from
~2~ 9
-- 3
the fluid trap, (ii) a first fluid line ~or connecting the
pump to the fluid trap to conduct fluid therebet~een, and
(iii~ a second fluid line for connecting the ~luid trap to
the body area, with the fluid trap located in series between
the pump and the body area, to conduct fluid between the
fluid trap and the body area, wherein the discharging means
includes: a body fluid outlet formed in a top of the fluid
trap; and a body fluid discharge tube extending downward
from the body fluid outlet, into a lower portion of the
fluid trap.
Also, the present invention relates to an
apparatus for oscillating an agitating fluid into and out
from a localized body area, comprising: a pump for forcing
the agitating fluid into and drawing the agitating fluid
from the body area in a continuous, cyclical manner; and
fluid delivery means for connecting the pump to the body
area to conduct the agitating fluid therebetween, and
including (i) a fluid trap for collecting body fluid
aspirated from the body area, and including means for
discharging body fluid from the fluid trap, (ii) a first
fluid line for connecting the pump to the fluid trap to
conduct fluid therebetween, and ~iii) a second fluid line
for connecting the fluid trap to the body area, with the
fluid trap located in series between the pump and the body
area, to conduct fluid between the fluid trap and the body
area, and wherein the fluid trap includes a liquid container
and a cover extending over the container; and the cover
forms an inlet for receiving the first fluid line and an
outlet for receiving the second fluid line.
Further, the present invention relates to an
apparatus for oscillating an agitating fluid into and out
from a localized body area, comprising: a pump for forcing
the agitating fluid into and drawing the agitating fluid
from the body area in a continuous, cyclical manner; and
~2~ Z~
4 --
fluid delivery means for connecting the pump to the body
area to conduct the agitating fluid therebetween, and
including ~i) a fluid trap for collecting body fluid
aspirated from the body area, and including means for
discharging body fluid from the fluid trap, (ii) a first
fluid line for connecting the pump to the fluid trap to
conduct fluid therebetween, and (iii) a second fluid line
for connecting the fluid trap to the body area, with the
fluid trap located in series between the pump and the body
area, to conduct fluid between the fluid trap and the body
area, and wherein the pump includes: oscillating means to
alternately inject the agitating fluid into and aspirate the
agitating fluid from the body area through the fluid
delivery means to agitate fluid in the body area; power
means connected to the oscillating means to drive the
oscillating means; first adjustable means connected to the
power means to control the rate at which the agitating fluid
is injected into the body area; and second adjustable means
connected to the power means to control the rate at which
the agitating fluid is aspirated from the body area.
~urther still, the present invention relates to an
apparatus for oscillating an agitating fluid into and out
from a localized body area, comprising: a pump for forcing
the agitating fluid into and drawing the agitating fluid
from the body area in a continuous/ cyclical manner; and
fluid delivery means for connecting the pump to the body
area to conduct the agitating fluid therebetween, and
including ~i) a fluid trap for collecting body fluid
aspirated from the body area, and including means for
discharging body fluid from the fluid trap, (ii) a first
fluid line for connecting the pump to the fluid trap to
conduct fluid therebetween, and (iii) a second fluid line
for connecting the fluid trap to the body area, with the
fluid trap located in series between the pump and the body
~6~2~3
- 4A -
area, to conduct fluid between the fluid trap and the body
area, and wherein the pump comprises: means forming a pump
inlet and a fluid chamber in communication therewith for
holding the agitating fluid; oscillating means ~or forcing
fluid outward from the fluid chamber and into the ~ody area,
and for drawing fluid inward from the body area and into the
fluid chamber; power means connected to the oscillating
means to drive the oscillating means; and control means
connected to the power means to control movement of the
oscillating means, the control means including, (i) switch
means having a first state actuating the power means to
force fluid outward from the pump and into the body area,
and a second state actuating the power means to draw fluid
from the body area and inward into the pump, the switch
means including first adjustable means to var~ the rate at
which fluid is forced into the body area, and second
adjustable means to vary the rate at which fluid is drawn
from the body area, and (ii) switch control means to change
the switch means between the first and second states, the
switch control means including (a) detector means generating
a first signal when the oscillating means reaches a first
position and generating a second signal when the oscillating
means reaches a second position, and (b) means connected to
the detector means for receiving the first and second
control signals therefrom, to change the switch means to the
second state in response to receiving the first control
signal from the first detector, and to change the switch
means to the first state in response to receiving the second
control signal from the second detector.
The present invention further relates to an
apparatus for oscillating an agitating fluid into and out
from a localized body area, comprising: a pump for forcing
the agitating fluid into and drawing the agitating fluid
from the body area in a continuous, cyclical manner; and
, f ~
22~
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fluid delivery means for connecting the pump to the body
area to conduct thP agitating fluid therebetween, and
including (i) a fluid trap for collecting body fluid
aspirated from the body area, and including means for
discharging body fluid from the fluid trap, (ii) a first
fluid line for connecting the pump to the fluid trap to
conduct fluid therebetween, and (iii) a second fluid line
for connecting the fluid trap to the body area, with the
fluid trap located in series between the pump and the body
area, to conduct fluid between the fluid trap and the body
area, and wherein the pump comprises: a support frame
including (i) a side section forming a front opening, (ii~
a front plate extending across the front opening and forming
a pump inlet, and (iii) means releasably connecting the
front plate to the side section; a cylinder for holding the
agitating fluid, located within the support frame and
forming a fluid chamber in communication with the pump
inlet; a piston extending into the fluid chamber and
supported for forward and rearward reciprocating movement
therein, to inject fluid outward from the fluid chamber and
into the body area and to aspirate fluid from the body area
and inward into the fluid chamber; power means supported by
the frame and connected to the piston to reciprocate the
piston in the fluid chamber; and means releasably connecting
the cylinder to the support frame including (i) support
means longitudinally extending rearward from the front
plate, and (ii) a retaining plate supported by the support
means, transversely extending across the cylinder, rearward
thereof, and capturing the cylinder between the front plate
and the retaining plate.
Further still, the present invention relates to a
pump for directing an oscillating fluid into and out from a
body area, the pump comprising: means forming a pump inlet
and a fluid c~amber in communication therewith for holding
æ
l'~g~2~9
- 4C -
the fluid; oscillating means for forcing fluid outward from
the fluid chamber and into the body area, and for dra~Jing
fluid inward from the body area and into the fluid chamber;
power means connected to the oscillating means to drive the
oscillating means; and control means connected to the power
means to control movement of the oscillating means, the
control means including (i) switch means having a first
state actuating the power means to force fluid outward from
the pump and into the body area, and a second state
actuating the power means to draw fluid from the body area
and inward into the pump, the switch means including first
adjustable means to vary the rate at which fluid is forced
into the body area, and second adjustable means to vary the
rate at which fluid is drawn from the body area, and (ii)
switch control means to change the switch means between the
first and second states, the switch control means including
(a) detector means generating a first signal when the
oscillat.ing means reaches a first position and generating a
second signal when the oscillating means reaches a second
position, and (b) means connected to the detector means for
receiving the first and second control signals therefrom, to
change the s~itch means to the second state in response to
receiving the first control signal from the first detector,
and to change the switch means to the first state in
response to receiving the second control signal from the
second detector.
Still further, the present invention relates to an
apparatus for agitating a therapeutic fluid introduced into
a localized area of a patient's body to dissolve solids
therein, the apparatus comprising: a pump including a pump
inlet and a fluid chamber in communication therewith for
holding an agitating fluid; fluid conducting means for
connecting the pump inlet to the localized area of the
patient's body, the pump further including (i) oscillating
~29~Z;~
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means to alternately inject the agitating fluid into and
aspirate the agitating fluid from the body area through the
fluid conducting means to ayitate the therapeutic fluid in
the body area, (ii) power means connected to the oscillating
means to drive the oscillating means, (iii) ~ i r s t
adjustable means connected to the power means to control the
rate at which fluid is injected into the body area, and (iv)
second adjustable means connected to the power means to
control the rate at which fluid is aspirated from the body
area.
In the accompanying drawings, Figure 1 is a block
diagram illustrating the method and apparatus of this
invention;
Figure 2 is a cross-sectional view of a fluid trap
that may be used in the apparatus shown in Figure 1;
Figure 3 is a top view of the cover of the fluid
trap;
Figure 4 is a plan view, partially in cross-
section, of a pump that may be used in the apparatus shown
in Figure 1;
Figure 5 is a side view of the pump shown in
Figure 4;
Figure 6 is a front view of the pump;
Figure 7 is a schematic drawing of an electric
control circuit for the pump;
Figure 8 shows an operating table for a logic
subcircuit of the electric control circuit;
Figure 9 shows an operating table for a flip-flop
of a stop-start subcircuit o~ the control shown in Figure 7.
Figure 1 schematically shows apparatus 10
comprising pump 12 for forcing fluid into and drawing the
fluid from a localized body area of a patient, and fluid
delivery means 14 for connecting the pump to that body area
,~
)"~.i
_5~ 2~
1 to conduct fluid therebetween. Fluid delivery means 14, in
turn, includes fluid trap 16, first fluid line or catheter 20
for connecting pump 12 to the trap, and second fluid line or
catheter 22 for connecting the trap, and hence the entire
apparatus 10, to the patient's body area.
To dissolve undesirable solids such as gallstones
or kidney stones that have formed in a localized body area of
a patient, a dissolving agent such as mono-octanoin or methyl
tertiary-butyl ether, is introduced into that body area.
This dissolving agent may be introduced into the body by any
suitable means e.g. catheter placement. Then, fluid line 22
is inserted into the patient to connect the patient to
apparatus 10 so that fluid trap 16 :Ls located in series
between the patient and pump 12. This tube or catheter 22
may be inserted into the patient's body in any acceptable way
such as through percutaneous transhepatic catheter placement,
endoscopic retrograde biliary catheter placement, or
placement of a T-tube into the localized area by surgical
means. Next, pump 12 is activated to inject an agitating
fluid into and to withdraw the agitating fluid from the
localized body area of the patient in a continuous, cyclical
manner. This oscillation of the agitating fluid stirs the
dissolving agent in the body area, and in particular, helps
to distribute and to agitate the dissolving agent, improving
the rate at which that agent dissolves the undesirable
concretions in the patient's body~
The pump 12 may be employed to oscillate the
agitating fluid into and out of the patient's body area in
various ways. For example, the pump may include liquid
chamber 24 in communication with fluid line 20, and means
such as piston 26 to alternately push fluid from chamber 24
into line 20 and then draw fluid from that line back into
chamber 24. Prior to actuation of apparatus 10, liquid
-6- ~2~
l chamber 24, trap 16, and lines 20 and 22 are filled with a
liquid agitating fluid, and then piston 26 is actuated to
oscillate agitating fluid between chamber 24 and line 20.
Because of the serial arrangement of pump 12, trap 16 and
lines 20 and 22, as pump 12 forces liquid into fluid line 20,
liquid is forced through line 20, trap 16, line 22, and into
the patient's body. Analogously, as liquid is drawn into
pump 12 from line 20, ]iquid is aspirated through line 20,
trap 16, line 22, and from the body of the patient.
Preferably, trap 16 and fluid lines 20 and 22 form a normally
closed fluid delivery system between pump 12 and the
patient's body --that is, there are no fluid leaks between
the ambient and lines 20 and 22 and trap 16. This closed
delivery system facilitates conducting fluid between pump 12
and the body of the patient and, in particular, helps to
control precisely the rate and quantity of that fluid flow.
As the agitating fluid is withdrawn from the
patient, it is possible that body fluids such as bile may be
withdrawn from the patient with the agitating fluid. Fluid
trap 16 is provided to collect the withdrawn body fluids
and to separate those fluids from the withdrawn agitating
fluid so that, as apparatus 10 continues to operate, the
separated agitating fluid is reinjected into the patient's
body area to further stir the dissolving agent therein
without also reinjecting the withdrawn body fluids into the
patient. Preferably, the withdrawn body fluids are separated
from the withdrawn agitating fluid by collecting the former
fluids in a first region of trap 16 and collecting the latter
fluid in a second region of the fluid trap. For example, if
the density of the agitating fluid is less than that of the
body fluids withdrawn from the patient, the desired
separation can be achieved by conducting all of these fluids
into an upper portion of trap 16, and allowing the body
fluids to settle in the bottom portion of the fluid trap
-7~
l while the agitating fluid remains in the upper portion
thereof. It is possible that solid materials such as stone
debris will also be withdrawn from the patient's body with
the agitating fluid, and trap 16 is employed to collect and
separate those solid materials from the agitating fluid in
the same way that the fluid trap collects and separates the
body fluids from the agitating fluid.
Figures 2 and 3 show details of a preferred fluid
trap 30 that may be used in apparatus 10; and this fluid trap
generally includes any suitable liquid container 32 and cover
34, and preferably, the trap also includes base 36. Cover 34
extends across the top of container 32 and forms inlet 40 and
outlet 42, both of which are in communication with the
interior of container 32. In use, fluid line 20 is held
within inlet 40 to connect container 32 to pump 12, and fluid
line 22 is held within outlet 42 to connect the container to
the patient. Llnes 20 and 22 may be held in openings 40 and
42 in any suitable way, for instance by simple frictional
engagement between the fluid lines and surfaces forming those
openings. Preferably, lines 20 and 22 also act as seals in
openings 40 and 42 to prevent air and other fluids from
leaking, either out of container 32 and into the ambient, or
into the container from the ambient, through openings 40 and
42. It should be noted that although openings 40 and 42 are
nominally referred to as inlet and outlet respéctively, fluid
is conducted into and discharged from container 32 through
each of these openings when fluid trap 30 is used in
apparatus 10.
Liquid container 32 is held between cover 34 and
base 36, which, in turn, are securely connected together by a
plurality of connecting rods 44 and wing nuts 46 (only one of
which is shown in Figure 2). Preferably, liquid container 32
is made from a transparent material to allow visual
29
1 inspection of the interior of that container, and rubber pad
50 is located between base 36 and the bottom of the liqllid
container to cushion the lower end thereof. When trap 30 is
used in the above-describe~ operation of apparatus 10, a
conventional pressure gauge (not shown) may be connected to
the fluid trap, in communication with the interior thereof,
to show the fluid pressure therein.
Preferably, fluid trap 30 is provided with means
for discharging body fluids from the trap without
interrupting the operation of the trap or apparatus 10. With
the fluid trap shown in Figures 2 and 3, this discharging
means comprises outlet 52 formed in the top of the trap, and
discharge tube 54 that extends downward from this outlet and
into the lower portion of the trap. Collected solid debris
may also be discharged from trap 30 through tube 54 and
outlet 52 without interrupting operation of the fluid trap or
apparatus 10.
Trap 30 may also include air discharge means --for
example comprising air outlet 56, air discharge tube 60 and
valve 62-- to vent air or other compressible vapors or gases
from the trap. These gases and vapors may be drawn into trap
30 from the patient's body area, from pump 12 or from the
ambient. Preferably, trap cover 34 has a cone shape, forming
an air space directly below the center of the trap cover, and
outlet 56 is formed in the trap cover, in communication with
that air space. Discharge tube 60 extends upward from outlet
56 and is covered by valve 62. Normally, valve 62 is closed,
and the valve may be opened by an operator to discharge gases
from trap 30. Seals (not shown) may be used to seal the
connections or interfaces between valve 62 and tube 60 and
between that tube and cover 34. Also, tube 60 may be
transparent to allow an operator to see when air has
- 9 12~6~2~
1 collected in the tube. While valve 62 is manually operated,
if desired, ~utomatic controls may be used to operate that
valve, as well as fluid discharge means 52 and 54.
With reference again to Figure 1, during the
above-described operation of appara~us 10, the same fluid
used as the dissolving agent may be used as the agitating or
oscillating fluid. Alternately, the agitating fluid may be a
mixture of liquids that does or does not include the
dissolving agent. ~Jater, organic solvents, or solvents for
the dissolving agent may also be used as or in the agitating
fluid.
It is normally desirable to maintain constant the
volume of liquid injected into and aspirated from the body of
the patient. Over time, however, agitating fluid may be lost
due to seepage from the body area or absorption into other
body parts. If this happens, preferably fluid may be added
to pump 12, without stopping the pump, to maintain an
effective amount of the agitating fluid therein. If the
dissolving agent is used as the agitating fluid, adding
dissolving agent to pump 12 from time to time may also
increase the effectiveness of the dissolving agent in vivo by
replacing dissolving fluid that has been become inactive.
The agitating fluid can be injected into the body
area of the patient and aspirated therefrom at various rates.
Specific infusion and aspiration rates and periods depend on
a number of factors such as the patient's tolexance, but the
normally preferred individual infusion and aspiration periods
are of the order of about 10-15 seconds. Also, it may be
desirable to start the infusion at a relatively slower rate,
and then gradually increase that rate to a level depending on
the patient's tolerance. The specific infusion and
aspiration rates depend, in part, on the pressure differences
that can be developed between pump 12 and the patient's body
22~
--10--
1 cavity. The pa$ient's body cavity is normally at about 1
atmosphere of pressure, and thus a pressure difference of
about 1 atmosphere is the maximum that can be developed
between pump 12 and the body cavity during an aspiration
cycle. This limits the maximum aspiration rate; and it has
been found, at least when used to dissolve gallstones in
vivo, that particularly good results may be obtained when the
infusion rate is greater than this maximum aspiration rate.
For example, when used to dissolve gallstones ln
vivo, a very carefully monitored volume, e.g. 5 ml, may be
rapidly infused through a small caliber catheter, e.g. 1.7 mm
external diameter, at a carefully controlled rate, and then
more slowly, but completely, aspirated in a cyclical fashion.
The rapid infusion requires a high pressure, carefully
controlled system; and the slow, complete aspiration inhibits
the introduction of air into the body area being treated
either as the result of the development of a low pressure
therein, or as the result of air leaking into pump 12. The
infusion and retrieval of the agitating fluid should be
closely monitored to avoid excessive overflow of the fluid
from the gallbladder and the absorption of that fluid into
the body.
Apparatus 10 may be used to dissolve many types of
solids in vivo such as kidney and urinary tract stones,
blockages in the digestive system, and intravascular blood
clots, atherosclerotic cholesterolplacques and other
undesirable matter in the arterial system. Also, pump 12 may
be used to oscillate a fluid into and out of a localiz~d body
area for purposes other than to facilitate the dissolution of
a solidified mass therein; and, for example, the pump may be
employed to distribute therapeutic agents such as other
therapeutic agents such as antibiotics or cancer combatants
throughout a localized or target area to enhance their
--11--
l surface contact or absorption. Further, pump 12 may be used
to enhance the local efficacy of hydrophobic therapeutic
agents which are poorly miscible or soluble in an aqueous
body fluid such as bile.
Any suitable pump may be employed in apparatus 10,
and, for example, a rotary pump, a bellows pump or a
reciprocating pump may be used to oscillate an agitating
fluid in the manner previously described. Figures 4-6
illustrate in detail a pump 100 that has been used in
apparatus 100, and Elgures 7-9 show and summarize the
operation of control circuit 200 for this pump.
Generally, pump 100 comprises support frame 101,
cylinder 102, piston 105 and power means such as electric
motor 106. Support frame 101 provides a protective structure
or enclosure for cylinder 102 and piston 105, and preferably
the support ~rame comprises longitudinally extending side
section 107 and front and back plates 110 and 111. Side
section 107 is formed of three rectangular plates having
longitudinal edges connected together to form a strong frame
having a U-shaped cross section. Side section 107 forms
front and back openings, and plates 110 and 111 extend across
these openings respectively. Front plate 110 supports
cylinder 102 inside pump 100, and the front plate forms pump
inlet 112 for conducting a fluid into and out from the
interior of that cylinder. Back plate 111 forms opening 115
receiving a shaft of motor 106, discussed below.
The various plates of support frame 101 may be made
of any suitable material and connected together in any
suitable way, and the support frame may have shapes other
than as illustrated in the drawings. For instance, the
plates of frame 101 may be made from aluminum and screwed or
bolted together to form the support frame. In use, the top
of support frame 101 may be covered, for e~ample, by a
~2~229
-12-
l plexiglass plate screwed to top edges of the support frame.
Alternately, side section 107 of support frame 101 may have a
tubular or cylindrical shape.
Preferably, regardless of the specific way the
other parts of support frame 101 are connected together,
front plate 110 is releasahly connected to side section 107.
This releasable connection may be made in a variety of ways.
For example, as illustrated in the drawings, front plate 110
defines a plurality of through hores 116 that are aligned
with threaded sockets 117 formed in the front edges of side
section 107. Pins 120, which have threaded front and back
portions, extend through bores 116 and are securely threaded
into sockets 117. Pins 120 extend forward of plate 110, and
wing nuts 121 are threaded onto front portions of those pins
and into a tight pressure fit against the front plate,
holding that plate securely against front edges of side
section 107.
Cylinder 102 is located inside support frame 101
and forms a fluid chamber 122 for holding a supply of the
fluid that is injected into and aspirated from the body of a
patient. As depicted in the drawings, cylinder 102 abuts
against front plate 110 and extends rearward therefrom, and
the cylinder includes tubular side wall 125 and a cylindrically
shaped head or plug 126. Head 126 is inserted into a forward
end of side wall 125, in a close fit therewith, and the head
is captured in place between front plate llO and an annular
shoulder formed in side wall 125. Alternately, head 126 may
be held in a tight frictional fit with side wall 125. Head
126 forms inlet portion 127 of fluid chamber 127, and a seal
may be fitted around the circumference of the head, against
side wall 125~ to seal the space between the head and the
tubular side wall. Head 126 and tubular side wall 125 may be
formed from stainless steel, and the circumferential seal
-13- ~'~229
l that is fitted on the outside of the head may be comprised of
a pair of split*Teflon washers. A catheter connection 130
may be fitted into inlet 127 to adapt pump 100 for connection
to a standard catheter tube.
Cylinder ]02 is connected to and held in place
inside support frame 101 by connecting means generally
comprising retaining plate 131 and means 132 supporting the
retaining plate inside the support frame. More specifically,
this suppor-t means 132 extends rearward from front plate 110;
and retaining plate 131 is supported by support means 132,
transversely extends across cylinder 102, rearward thereof,
and captures the cylinder between the front plate and the
retaining plate.
Preferably, support means 132 comprises a pair of
support rods 135 and 136 extending rearward from front plate
110. More particularly, support rods 135 and 136
longitudinally extend completely across support frame 101 and
rear ends of the support rods are threaded into threaded
bores formed in back plate 111. Support rods 135 and 136
also extend slightly forward of front plate 110, and wing
nuts 137 are mounted on the front ends of the support rods
and threaded into tight pressure engagement with the front
plate, holding the support rods taught between the front and
back plates.
With the pump 100 shown in Figures 4-6, retaining
plate 131 forms a pair of outside openings 140 and support
rods 135 and 136 extend through these openings to mount the
retaining plate on those rods. Retaining plate 131 also
forms a central openings 141 through which piston 105
30 extends. Support rods 135 and 136 form annular shoulders 141
rearward of plate 131 to limit rearward movement thereof, and
spacing sleeves 142 are mounted on the support rods forward
of the retaining plate to limit forward movement thereof.
*trade mark
-14- ~ 9
l Preferably, retaining plate 131 is tightly captured between
sleeves 142 and shoulders 141; and, in turn, cylinder 102 is
tightly held between the retaining plate and front plate 110.
Plates 110 and 131 may form longitudinally aligned, axial
recesses that receive opposite ends of cylinder 102 to help
hold the cylinder in place inside pump 100.
As will be appreciated by those of ordinary skill
in the art, retaining plate 131 may be held within support
frame 101 in a variety of other ways. In particular, it
should be noted that the plate 131 may be longitudinally held
in place by the combination of a single shoulder 141 and a
single sleeve 142 formed and mounted respectively on a
support rod. Retaining plate 131, rods 135 and 136, and
sleeves 142 are preferably made from aluminum, although other
materials may be used.
Piston 105 extends into cylinder 102 and is
supported therein for forward and rearward reciprGcating
movement to force fluid outward from chamber 122 and into the
patient and to aspirate fluid from the patient and into
chamber 122. More particularly, piston 105 has a generally
cylindrical shape, and extends into fluid chamber 122 in a
close sliding fit with the inside surfaces of tubular side
wall 125. One or more outside circumferential seals may be
seated on piston 105 to seal the annular gap between the
piston and cylinder 102. Piston 105 may be made from
stainless steel, and the seals that are mounted on the piston
may be comprised of pairs of split Teflon washers. Piston
105 shown in Figure 4 includes a~ially aligned front, or
head, section 145 and back, or driving, section 146. Driving
section 146 comprises a conventional screw nut, and a rear
portion of head section 145 is threaded onto a forward
portion of this screw nut so that the two sections of piston
105 longitudinally move together inside support frame 101.
229
-15-
l Screw nut 146 forms a longitudinally extending threaded bore
147 and is supported in pump 100 in a manner that prevents
rotation of the screw nut. For instance, bar 150 m~y be
mounted on support rods 135 and 136 and connected to scre~
nut 146 of piston 105 by one or more set screws to prevent
rotation of the screw nut and, thus, of the piston relative
to support frame 101.
Motor 106 is secured to support frame 101 and is
connected to piston 105 to reciprocate the piston in cylinder
102. Various types of motors may be used with pump 100, and
the motor may be connected to support frame 101 in any
acceptable way. Preferably, motor 106 is a conv~ntional
direct current motor including a speed reducing section and a
rotatable output shaft 151, and the motor is bolted to back
plate lll ol support frame 101 with the output shaft
extending through opening 115.
Also, motor 106 may be connected to piston 105 in
any suitable way. With the preferred embodiment of pump 100
shown in the drawings, motor shaft 151 is connected to drive
rod 152, which may comprise a conventional drive screw, via a
coupling mem~er 155 that transmits rotary motion from the
motor shaft to the drive screw. Drive screw 152 itself
extends forward from coupling member 155 and includes a
threaded forward portion that extends into and engages the
threads of piston bore 147. With the above-described
arrangement, rotation of shaft 151 rotates drive rod 152;
however, driving section 146 of piston 105 is prevented from
rotating, and thus rotation of the drive rod against the
threads of bore 147 forces the piston forward or rearward in
cylinder 102, depending on the direction of rotation of the
drive rod.
Cross-plate 156 is connected to and transversely
extends across side section 107 to support and hold drive rod
152 and coupling member 155 in position. Plate 156 is
-16- ~9~
l located between retaining plate 131 and back plate 111, and
preferably is slightly forward of coupling member 155.
Central opening 157 is formed in plate 156, and the rear end
of drive rod 152 extends into this opening. A bearing (not
shown) may be located in opening 157 and directly engage and
support the rear end of drive rod 152. Cross-plate 156 also
forms a pair of outside openings through which support rods
135 and 136 e~tend.
~referably, pump 100 further comprises auxiliary
inlet means 160, shown in Figure 5, to conduct additional
fluid into fluid chamber 122 during operation of the pump;
and this inlet means includes bore 161, connecting tube 162,
and valve 165. Bore 161 is formed in and extends through
side wall 125 of cylinder 102, in communication with fluid
chamber 122. Connecting tube 162 has a first end located in
bore 161 and extends outward therefrom, and valve 165 is
connected to the connecting tube, for example to a second end
thereof, to control the flow of fluid through the connecting
tube. Preferably, valve 165 itself includes an inlet to
connect the valve to a source of the additional fluid; and
the valve has an open position for conducting fluid from this
inlet to connecting tube 162, and a closed position to
prevent fluid flow between the valve inlet and connecting
tube~ With this preferred arrangement, valve 165 further
inc].udes a control, such as a handle that may be moved by
hand by an operator, to move the valve between its open and
closed positions.
Control means are provided to control the
direction, the distance and the speed of movement of piston
105 in cylinder 102 and hence the volume and the rate of
fluid injected into and aspirated from the patient. This
control means includes front detector 166, which generates a
first signal when piston 105 reaches a predetermined forward
1 position, and rear detector 167 which generates a second
signal when the piston reaches a predetermined rearward
position. The operation of these detectors and the way they
cooperate to control movement of piston 105 are discussed in
detail below. The structure of each of these detectors,
though, is comprised of a U-shaped bracket having spaced
first and second legs, radiation sensitive means located on
the first leg, and radiation generating means located on the
second leg.
Front detector 166 is connected to support frame
101, specifically side wall lOla. With reference to
Figure 6, detector 166 is mounted on L-shaped plate 170, and
screw 171 extends through side wall lOla and engages this
plate to hold the plate securely against that side wall.
Rear detector 167 is similarly connected to support frame
101, specifically side wall lOlb, by means of L~shaped plate
172 and screw 173 that extends through side wall lOlb into
engagement with plate l72. Both detectors 166 and 167 are
located rearward of and at a level below cylinder 102. Front
detector 166 is located forward of rear detector 167, and the
rear detector is located forward of cross-plate 156.
As shown in Figure 5, side wall lOlb forms
elongated slot 175, and screw 173 extends through this slot
to hold plate 172 against the side wall. The position of
detector 167 may be changed by simply loosening screw 173,
moving the screw, plate 172 and detector 167 along slot 175
to a new position, ana then retightening screw 173 in this
new position. A similar slot (not shown) is formed in side
wall lOla to allow an easy adjustment of the position of
plate 170 and detector 166. Pins 176 extend through slot 175
and into engagement with plate 172 to help hold that plate
and detector 167 level inside support frame 101, and similar
pins (not shown) may be likewise used to help hold plate 170
and detector 166 level inside the support frame.
~2~Çi22~
-18-
1 Actuating means is mounted on piston 105 and
actuates front ana rear detectors 166 and 167 to generate the
above-mentioned first and second signals. Preferably, this
actuating means lncludes the previously discussed
transversely extending bar 150, which is mounted on piston
105 and support rods 135 and 136, and a pair of plates or
flags 177 and 178 that are connected to and extend downward
from outward portions of bar 150. Plates 177 and 178 are
positioned so that, first, when piston 105 reaches the
above-mentioned predetermined forward position, plate 177 is
located between the legs of front detector 166 to block the
radiation sensitive means thereof from the radiation
generating means of the first detector; and second, when the
piston reaches the above-mentioned predetermined rearward
position, plate 178 is located between the legs of rear
detector 167 to block the radiation sensitive means thereof
from the radiation generatin~ means of the rear detector. A
pair of bushings may be mounted on support rods 135 and 136,
between those rods and bar 150, to facilitate sliding
movement of the bar along the support rods.
An advantage of pump 100 is that cylinder 102 and
head section 145 of piston 105, the parts of the pump that
may come into direct contact with fluid injected into and
aspirated from the body of the patient, can be easily removed
and replaced. To do this, wing nuts 121 and 137 are removed
and front plate 110 is pullea away from the front edges of
side section 107. Cylinder 102 is pulled off piston 105 and
removed from pump 100, and then head section 145 of the
piston is threaded ofi driving section 146 and removed.
Cylinder 102 and head section 145 may then be thoroughly
cleaned and sterilized and replaced, or another cylinder and
another pis~on head section may be installed in pump 100.
- 1 9 ~ 36~
l With front plate 110, cylinder 102, and piston head section
145 removed, it is also very easy to remove sleeves 142,
retaining plate 131 and piston driving section 1~6. To
elaborate, sleeves 142 and retaining plate 131 may be removed
by simply sliding these parts forward off support rods 135
and 136. Drive section 146 is removed by disconnecting it
from bar 150 and then threading the driving section forward
off drive rod 152.
To replace piston 105, retaining plate 131, sleeves
1~2, and cylinder 102, driving section 146 of the piston is
threaded onto drive rod 152 and then connected to bar 150 so
that this bar prevents rotation of the piston drive section.
Retaining plate 131 is mounted on support rods 135 and 136
and slid rearward, against shoulders 141, and then sleeves
142 are mounted on the support rods and slid against the
retaining plate. Head section 145 of piston 105 is threaded
onto piston driving section 146 and then cylinder 102 is slid
onto the piston. With cylinder 102 and piston 105 in place,
fron~ plate 110 is then mounted on pins 120 and rods 135 and
20 136 as shown in Figures 4 and 5, and wing nuts 121 and 137
are threaded onto those pins and rods respectively, securely
connecting the front plate to side section 107 and tightly
holding the support rods between the front and back plates of
support frame 101.
Figure 7 is a schematic diagram of an electric
control circuit 200 for pump 100, and in particular for motor
106. Generally, circuit 200 lncludes switch means 200a and
switch control means 200b. Switch means 200a has a first
position or state actuating motor 106 to move piston 105
forward in cylinder 102, and a second position or state
actuating the motor to move the piston rearward in the
cylinder; and this switch means includes forward and rearward
speed control means to vary, respectively, the forward and
-20~ 229
l rearward speeds of the piston in fluld chamber 122 and,
hence, the rate at which fluid is injected into and aspirated
from the body area being treated. Switch control means 200b
is provided to change switch means 200a from its first
state to its second state when piston 105 reaches a
predetermined forward position, and to change the switch
means from its second state to its first state when the
piston reaches a predetermined rearward position. With the
embodiment of the control circuit shown in Figure 7, switch
means 200a includes controller 201, relay coils 202 and 205,
and potentiometers 206 and 207; and switch control means 200b
includes front detector 166, back detector 167, logic
subcircuit 210 and stop-start subcircuit 211.
Controller 201 is a conventional motor control that
governs the direction and speed of rotation of motor shaft
151 by controlling the polarity and magnitude of the voltage
applied to the windings of motor 106, and this is done in
response to the polarity and magnitude of the voltage applied
to an input 201a of the controller, referred to as the
command control input. Controller 201 has two output
connections 201b and 201c that are connected to motor 106,
and the controller provides +lOV and -lOV Direct Current
potential sources. Controllers of this type are well known
in the art and, for example, controller 201 may comprise
controller model number E-352-B manufactured by the
Motorcraft Company Inc.
Relay coil 202 includes a magnetic coil 202a and
switch 202b. Switch 202b is normally open, and the switch
closes when a current of sufficient magnitude is conducted
through coil 202a. ~hen this happens, switch 202b connects
controller command input 201a to a -10 DC voltage source, via
line 202c, so that piston 105 is pulled rearward in cylinder
102. A first end of coil 202a is connected to voltage source
El, and a second end of this coil is connected to a first
~2~229
l ou-tput eonnection of logie subeireuit 210, diseussea in
detail below. When this output eonneetion of logie eireuit
210 is at a high voltage level, eurrent does not flow through
eoil 202a and switch 202b is open. Ho~ever, when this first
output eonnection of the logic suheircuit is at a low voltage
level, a voltage difference exists across coil 202a; and this
causes current to flow through that eoil, closlng switch
202b, and aetuating motor 106 to move piston 105 rearward in
eylinder 102. Variable potentiometer 206 is loeated in line
202e to vary the magnitude of the voltage applied to
controller eommand input 201a when switeh 202b is elosed and,
in this way, the speed at which motor 106 pulls 202b piston
105 rearwardly and the rate at which the piston aspirates
fluid from the patient.
Relay coil 205, similar to relay coil 202, includes
magnetic coil 205a and switeh 205b. Switch 205b is normally
open, and the switch closes when a current of sufficient
magnitude is conducted through coil 205a. When this happens,
switeh 205b conneets controller eommand input 201a to a +10
DC voltage source, via line 205c, and this causes the
eontroller to actuate motor 106 so that piston 105 is pushed
forward in cylinder 102. A first end of eoil 205a is
eonneeted to a voltage souree E2, and a seeond end of this
eoil is eonneeted to a seeond output eonnection of logic
subeireuit 210. When this output connection of logic
subeireuit 210 is at a high voltage level, eurrent does not
flow through coil 205a, and switeh 205b is open. When this
seeond output eonneetion of logie subeircuit 210 is at a low
voltage level, however, a voltage differenee exists aeross
eoil 205a; and this eauses eurrent to flow through that eoil,
elosing switeh 205b and aetuating motor 106 to move piston
105 forward in eylinder 102.
-22- ~9~
1 Variable potentiometer 207 is located in line 205
to vary the magnitude of the voltage applied to controller
command input when switch 205b is closed and, thereby, the
speed at which the motor pushes piston 105 forward and the
rate at which the fluid in pump 100 is injected into the
patient. By providing separate potentiometers 206 and 207,
each one controlling the speed of piston 105 in a different
direction, the speeds at which the piston moves forward and
rearward in cylinder 102 and the rate at which the fluid is
injected into and aspirated from the patient can be
controlled separately and independently.
Switch control means 200b controls the operation of
relay coils 202 and 205 in response to, first, signals
generated by front and rear detectors 166 and 167, and
second, a signal generated by stop-start subcircuit 211.
Front detector 166 includes radiation emitting
diode 166a, radiation sensitive transistor couple 166b, and
output connection 166c. ~iode 166a is electrically located
in line 166d between voltage source E3 and ground, transistor
couple 166b is electrically located in line 166e between
voltage source E4 and ground, and output connection 166c is
also located in line 166e between voltage source E3 and
transistor couple 166b. A 500k resistor is located in line
166d to limit the current through diode 166a; and a lOk
resistor is located in line 166e, between voltage source E3
and output connection 166c, to insure a voltage drop across
that portion of line 166e.
In the absence of the appropriate radiation,
transistor couple 166b is nonconductive, in effect acting as
an open switch in line 166e; and when the transistor couple
is in this state, output point 166c of detector 166 has
a relatively high potential such as one or two volts.
However, when radiation having a sufficient intensity in a
-23- ~9~29
1 predetermined wavelength range strikes base 166f of
transistor couple 166b, the transistor couple is rendered
conductive, in effect acting as a closed switch in line 166e;
and when the transistor couple is in this state, the voltage
potential of point 166c drops to a low potential such as zero
volts. Diode 166a is provided to selectively render
transistor couple 166b conductive. To elaborate, diode 166a
and transistor couple 166b are physically located on opposite
legs of U-shaped bracket 166g, with the diode immediately
opposite and closely adjacent base 166f of the transistor
couple. When current from voltage source E3 passes through
diode 166a, the diode emits radiation that, unless blocked,
strikes base 166f of transistor couple 166b and causes that
transistor couple to become conductive.
In the operation of pump 100, normally base 166e of
transistor couple 166a is not blocked from the radiation
emitted by diode 166a, and the transistor couple is
conductive and point 166c is at a low voltage potential.
However, when piston 105 reaches a predetermined forward
20 position in cylinder 102, plate 177 is pulled between diode
- 166a and transistor couple 166b, blocking the latter from the
radiation emitted by the former. This renders transistor
couple 166b nonconductive, bringing point 166c to a
relatively high voltage level.
Back detector 167 includes diode 167a, transistor
couple 167b, output connection 167c, lines 167d and 167e, and
transistor base 167f. The various elements of detector 167
are arranged and operated in a manner substantially identical
to the way the corresponding elements of detector 166 are
arranged and operated. The principal differences between
detectors 166 and 167 are that they are physically located on
different U-brackets and are employed to sense different
~2~
l positions of piston 105. Also, diode 167a and transistor
couple 167b are connected to voltage sources E5 and E6
respectively.
During use of pump 100, normally, base 167f o
transistor couple 167b is not blocked from the radiation of
diode 167a, and the transistor couple is conductive and point
167c is at a low voltage potential. When piston 105 reaches
a preset rearward location in cylinder 102, plate 17~ is
pulled between diode 167a and transistor couple 167b,
blocking the latter from khe radiation emitted by the former.
This causes transistor couple 167b to become nonconductive,
raising the voltage level of point 167c to a relatively high
level. While various types of transistor couples may be used
in the practice of this invention, preferably transistor
couples 166b and 167b are of a type that are rendered
conductive by electromagnetic radiation in the infrared
frequency range, and of course diodes 166a and 167a are of a
type that emit such radiation.
Logic subcircuit 210 is electrically located
between relay coils 202 and 205, on the one hand, and
detectors 166 and 167 on the other hand; and this subcircuit
includes flip flop 212, two nand gates 215 and 216, and two
voltage inverters 217 and 220.
Flip flops, such as flip flop 212, of circuit 200,
are electronic devices having a plurality of inputs and
outputs, and a number of useful characteristics. First, flip
flops have a pair of output connections or signals that
maintain an opposite relationship --when one of these output
connections has a high voltage potential, the other output
connection has a low voltage potential, and vise versa.
Second, flip flops can be constructed so that, if certain
input and output conditions are present, the output
connections change whenever either input connection changes;
-25-
1 but, if cert~in other input and output connections are
present, a single change in the input conditions has no
affect on the output conditions.
Flip flop 212 of circuit 200 has two input
connections 212a and 212b and two output connections 212c and
212d. Input connection 212a is connected to output
connection 166c of detector 166 via line 221; and voltage
inverter 217 is located in this line so that when detector
output connection 166c has a high voltage level, flip flop
input connection 212a has a low voltage level, and when
detector output connection 166c has a low voltage level, flip
flop input connection 212a has a high voltage level. Input
connection 212b is connected to output connection 167c of
detector 167 via line 222; and voltage inverter 220 is
located in this line so that when detector output connection
167c has a high voltage level, flip flop input connection
212b has a low voltage level, and when detector output
connection 167c has a low voltage level, flip flop input
connection 212b has a high voltage level.
Figure 8 summarizes the operation of flip flop 212.
When both input connections 212a and 212b are at a high
voltage potential, if either one of these input connections
changes to a low voltage potential, then each output
connection 212c and 212d of the flip flop changes either from
a high voltage potential to a low voltage potential or vise
versa. However, when one of input connections 212a and 212b
is at a high voltage potential and the other input connection
is at a low voltage connection, then a single change in the
voltage level of either one of these input connections has no
affect on the voltage potentials of output connections 212c
and 212d.
-26- ~ 2 ~ ~ 2 ~
l Nand gates, such as gates 215 and 216 of circuit
200, are ele~tronic logic devices having two input
connections and one output connection, and Figure 8
summarizes their operation. The output connection of a nand
gate has a low voltage potential only when both input
connections have a high voltage potential. Otherwise, the
output of a nand gate has a high voltage potential
Input connections 215a and 216a of nand gates 215
and 216 are connected to output connections 212c and 212d
respectively of flip flop 212. In this way, input
connections 215a and 216a are always at different voltage
levels --when the former connection is at a high voltage
potential, the latter connection is at a low voltage
potential, and vise versa. Input connections 215b and 216b
of nand gates 215 and 216 are connected to stop-start
subcircuit 211, discussed below. Output connection 215c of
the nand gate 215 forms the above-mentioned first output
connection of logic subcircuit 210 and is connected to rel~y
coil 202, and output connection 216c of nand gate 216 forms
the above-mentioned second output connection of the logic
subcircuit and is connected to relay coil 205.
Stop-start subcircuit 211 is provided to initiate
and terminate movement of piston 105 in cylinder 102; and
this subcircuit includes flip flop 225, start and stop
buttons, identified as START and STOP respectively in Figure
7, detector error sensor section 226, and safety sensor
section 227.
Flip`flop 225 has three inputs and two outputs. A
first input 225a of flip flop 225, referred to as the data
input, is connected to voltage source E7, which maintains the
data input of the flip flop at a high voltage level. START
switch is connected to a second input 225b of flip flop 225,
referred to as the clock input, via line 230; and detector
-27- ~Z~2~
l error sensor section 226, safety sensor section 227, and STOP
switch are all connected to a third input 225c of the flip
flop, referred to as the reset input, via line 231. Only one
of the outputs of flip flop 225 is used in circuit 200, and
this output 225d is connected to inputs 215b and 216b of nand
gates 215 and 216.
~ igure 9 summarizes the operation of flip flop 225.
As can be seen, when the voltage level of reset connection
225c is at a low voltage level, output connection 225d is
also at a low voltage level. However, when reset connection
225c is at a high voltage level, the voltage level of data
input connection 225a is transferred to output connection
225d when the STA~T switch is closed and then opened. When
output eonnection 225d is at a high voltage level, it will
stay at that level until either data input connection 225a or
reset connection 225e drop to a low voltage level, at which
time the output connection 225d also falls to a low voltage
level. Thus, with the arrangement of this invention, where
data input connection 225a is kept at a high voltage level,
output eonneetion 225d will switeh from a high voltage level
to a low voltage level, if and only if reset eonneetion 225e
assumes a low voltage level.
When output eonneetion 225d of flip flop 225 is at
a high voltage level, the voltage levels of one or the other
of output eonnections 215c and 216c is at a low voltage
level. Thus, motor 106 is operating, with the direction of
movement of piston 105 being determined by which Nand gate
output connection has the low voltage potential, and this in
turn is determined by which of the outputs of flip flop 212
has a high voltage level. However, when output connection
225d of flip flop 225 is at a low voltage level, output
connections 215c and 216c of Nand gakes 215 and 216 are both
at a high voltage level, regardless of the voltage levels of
-28- ~29~2~
1 input 215a and 216a of the Nand gates. Thusr motor 106 is
deactivated regardless of the voltage levels of output
connections 215c and 216c of flip flop 212.
START switch is used to start pump 100, and
specifically, motor 106. To elaborate, when motor 106 is not
operating, output connection 225d of flip flop 225 is at a
low voltage level, and START switch is employed to bring
input connection 225b of the flip flop temporarily to a low
voltage level to change the output connection 225d to a high
voltage level. START switch is located between an end of
line 230 and ~round, and voltage source E8 is also connected
to line 230 at point 230a, via line 232. A 10k resistor (not
shown) is located in line 232 to insure a voltage drop
thereacross. Normally, START switch is open, and the voltage
level at points 230a and 225b is at a relatively high level.
However, when START switch is closed, the switch shunts
current from the voltage source E8 to ground, bringing the
voltage level at point 225b to a low voltage level,
approximately zero.
Detector error sensor section 226, safety sensor
section 227, and STOP switch are used to stop pump 100,
either automatically upon the occurrence of a predetermined
condition, or at the will of an operator. More specifically,
when motor 106 is operating, output connection 225d of flip
flop 225 is at a high voltage level; and detector error
sensor section 226, safety section 227, and STOP switch may
be employed to bring input connection 225c of the flip flop
to a low voltage level to change the output connection 225d
thereof to a low voltage level.
Detector error sensor section 226 is connected to
line 231 at point 231a, safety sensor section 227 is
connected to line 231 at point 231b, and STOP switch is
connected to line 231 at point 231c. Voltage source Eg is
-29- ~ 2~
1 also connected to line 231, with points 231a, 231b, and 231c
located in series in line 231 between voltage source Eg and
input 225c of flip flop 225. ~ lOk resistor is located in
line 231, between voltage source E9 and point 231a, to insure
a voltage drop across this portion of line 231, and the
voltage level at input 225c of flip flop 225 normally is
maintained by voltage source Eg at a relatively high level.
However, if the voltage level of any one of points 231a, 231b
or 231c falls to a low level, then the voltage level at flip
flop input 225c also falls to a low voltage potential.
Detector error sensor section 226 stops operation
of pump 100 in case detector output co~nections 166c and 167c
are both at a high voltage potential at the same time, a
condition that should not occur during normal operation of
the pump. Detector error sensor section 226 comprises nand
gate 235, which has two input connections 235a and 235b and
an output connection 235c. Input 235a is connected to output
166c of detector 166 via line 236 so that the voltage levels
of points 235a and 166c are the same; and, similarly, input
235b is connected to output 167c of detector 167 via line 237
so that connections 235b and 167c are at the same voltage
level. With reference to Figure 8, output connection 235c of
nand ~ate 235 has a high voltage level unless both input
connections are at a high voltage level, in which case the
output connection of the nand gate has a low voltage level.
When this happens, input 225c of flip flop 225 also falls to
a low voltage level.
Safety sensor section 227 senses a parameter such
as the fluid pressure in cylinder 102 and stops operation of
pump 100 in case the value of the sensed parameter moves
outside a desired range; and this section of circuit 200
comprises comparator 240, variable potentiometer 241, and
sensor 242, Comparator 240 has two inputs 240a and 240b and
~Z9~2~3
1 one output 240c; and if the voltage level at input 240a is
greater than the voltage level at input 240b, then output
connection 240c is at a high voltage level; however, if the
voltage level of input 240b rises above the voltage level of
input 240a, then the voltage level of output connection 240c
drops to approximately zero.
Potentiometer 241 is located in line 245, between
voltage source Elo and ground, and the potentiometer is
connected to and determines the voltage level of inpu$ 240a
of comparator 240. Sensor 242 may be any suitable sensor
that produces an electric voltage potential indicative of a
particular parameter, and the sensor is connected to and
determines the voltage level of input 240b of comparator 240.
For instance, sensor 242 may be a pressure transducer that is
connected to a fluid line that, in turn, is connected to the
interior of cylinder 102, for example via valve 165, such
that the sensor is subject to, and produces an electric
potential corresponding to, the fluid pressure inside
cylinder 102. Other parameters may be sensed, however; and
in fact, with modifications well within the ability of one of
ordinary skill in the art, circuit 200 may be designed to
sense a multitude of parameters simultaneously and to stop
pump 100 in case any one of the sensed parameters falls
outside a predetermined range.
With the above-described arrangement, as long as
the value of the sensed parameter stays in a predetermined
range, output connection 240c of comparator 240 has a high
voltage level, but when that sensed parameter moves outside
the predetermined range, the output connection of the
compara$or drops to a low voltage level. This predetermined
range of the sensed parameter, and specifically the value
thereof at which output 240c of comparator 240 changes from
high voltage level to a low voltage level, may be adjusted by
changing the value of potentiometer 241.
-31~ 2~
1 STOP switch is located in line 246 between point
231c and ground, and normally the stop switch is open,
blocking current flow through line 246. However, if the STOP
switch is closed, the switch connects point 231c to ground,
bringing the electric potential of that point and input 225c
connection of flip flop 225 to a zero potential.
The operation of pump 100 and circuit 200 will be
clear to those of ordinary skill in the art from a review of
the above discussion. Nevertheless, that operation will be
summarized below.
When pump 100 is deactivated, piston 105 is at
rest, START and STOP switches are both open, and output
connection 225d of flip flop 225 is at a low voltage level.
The specific positions of piston 105 and plates 180 and 181
depend on where the piston was last stopped in pump 100, and
the specific condition of flip flop 212 depends on where the
piston is and the direction in which the piston was moving
when it was last stopped. For the sake of discussion, piston
105 will be considered to be in the position shown in Figure
4~ and flip flop 212 will be considered to be in condition
number 3 of Figure 8. Thus plates 180 and 181 are spaced
from detectors 166 and 167, both transistor couples 166b and
167b are conductive, and points 166c and 167c are at a low
voltage level. Output 212c of flip flop 212 and input 215a
of nand gate 215 are both at a high voltage level, and output
212d of the flip flop and input 212b of nand gate 216 are
both at a low voltage level. However, inputs 215b and 216b
of nand gates 215 and 216 are both at a low voltage potential
because of their connection to flip flop 225. Consequently,
nand gate outputs 215c and 216c are both at a high voltage
level, and switches 202b and 205b are both open.
To start pump 100, START switch is momentarily
closed and then opened. This causes output connection 225d
~L2~
-32-
l of flip flop 225 to change to a high voltaye level, and this
brings both input connections 215b and 216b of nana gates 215
and 216 to a high voltage level, in effect transferring
control of switches 202b and 205b to flip flop 212. Since
input connections 215a and 216a are at high and low voltage
potentials respectively, output connection 215c of nand gate
215 changes to a low voltage level when input connec-tion 215b
changes to a high voltage level. Current is conducted
through relay coil 202 and to control input 201a via switch
202b, and motor 106 is actuated to pull piston 105 rearward
in cylinder 102, with the speed of the piston determined by
potentiometer 206. Output connection 216c of nand gate 216
remains at a high voltage level because input connection 216a
thereof is at a low voltage level, and switch 205b remains
open-
Piston 105 continues to move rearward until plate
178 moves between the legs of bracket 167g. When this
oceurs, plate 181 blocks transistor eouple 167b from the
light of diode 167a, and the transistor eouple is rendered
nonconductive. This ehanges the voltage at point 167e from a
low to a high level, and input 212b of flip flop ehanges from
a high voltage level to a low voltage level. This eauses the
voltage levels of flip flop outputs 212e and 212d to flip,
and specifieally, the former point ehanges to a low voltage
potential and the latter point changes to a high voltage
potential. Now, the voltages of nand gate inputs 215a and
216a flip to high and low levels respectively, and the
voltages of nand gates outputs 215e and 216c ehange to high
and low levels respectively. With these voltages, current
stops flowing through relay eoil 202 and starts to pass
through relay coil 205, opening switeh 202b and closing
switch 205b. Current is conducted to controller command
input 201a via switch 205b, and motor 106 is operated to push
piston 105 forward in cylinder 102.
2~
-33-
l As piston 105 moves forward, plate 178 pulls away
from bracket 167g, and radiation from diode 167a renders
transistor couple 167b conductive. This causes the voltages
at points 167c and 212b to change to low and high levels
respectively. Nevertheless, as shown Figure 8, this change
in the voltage level of point 212b of flip flop 212 does not
affect the voltage level of output connections 212c and 212d
of the flip flop. The voltage level of the input and output
connections of nand gates 215 and 216 remain unchanged,
switch 202b remains open, switch 205b remains closed and
piston 105 continues to move forward.
Piston 105 continues to move .orward in cylinder
102, until plate 177 comes between the legs of bracket 166g
and bloc~s the radiation of diode 166a from base 166f of
transistor couple 166b. When this happens, transistor couple
166b becomes nonconductive, and the voltage at point 166c
changes to a high level, and the voltage at flip flop input
connection 212a changes to a low level. This change in the
voltage level at input connection 212a of flip flop 212
causes voltage levels of outputs 212c and 212d to flip --the
voltage of the former output connection increases to a high
level and the voltage of the latter output connection falls
to a low level. As a result, the voltages at input
connections 215a and 216a of nand gates 215 and 216 also
change to high and low levels respectively. The voltage of
output connection 216c of nand gate 215 changes to a low
level, and the voltage of output connection 216c of nand gate
216 changes to a high level. Current stops flowing through
relay coil 205 and switch 205b opens, and current begins to
conduct through relay coil 202 so that switch 202b is closed.
Current is now conducted to controller command input via line
202c, causing motor 106 to pull piston 105 rearward in
cylinder 102.
-34-
1 As piston 105 moves rearward, plate 177 moves awa~
from bracket 166g, and radiation from diode 166a causes
transistor couple 166b to become conductive. This changes
the voltage at point 166c to a low level and the voltage at
input 212a of flip flop 212 to a high level. The voltages of
output connections 212c and 212d of flip flop 212 remain the
same, however, as shown in Figure 8. The voltage levels of
the input and outpwt connections of nand gates 215 and 216
are unchanged, switch 202b stays closed, switch 205b remains
open, and piston 105 continues to move rearward.
Preferably, back-up means comprising forward and
rearward limit switches 246 and 247 and voltage sources E
and E12 is provided to reverse movement of piston 105 if
detectors 166 and 167 do not do so. Forward limit switch 24~6
is connected to support frame 101, forward of front detector
166 and at a height level with bar 150, and this limit switch
is electrically located in line 221 between the front
detector and inverter 217. Voltage source Ell is also
connected to line 221 via point 221a, between switch 246 and
inverter 220. As piston 105 moves forward in cylinder 102,
if detector 166 does not reverse movement of the piston,
continued forward movement of the piston causes bar 150 to
contact and open switch 246. This disconnects flip flop 212
from transistor couple 166b and voltage source E4; however,
voltage source Ell remains connected to line 221 and causes
point 221a to assume a high voltage level. Inverter 217
causes a low voltage to be applied to flip flop input 212a,
causing motor 106 to reverse the direction of movement of
piston 105.
Rearward limit switch 247 is connected to support
frame 101, rearward of rear detector 167 and at a height
level with bar 150, and this limit switch is electrically
-35~
1 located in line 222 between the rear detector and inverter
220. Voltage source E12 is also connected to line 222 via
point 222a, between switch 247 and inverter 217. As piston
105 moves rearward in cylinder 102, if detector 167 does not
reverse movement of ~he piston, continued rearward movement
of the piston causes bar 150 to contact and open switch 247.
This disconnects flip flop 212 from transistor couple 167b
and voltage source E6; however, voltage source E12 remains
connected to line 222 and causes point 222a to assume a high
voltage level. Inverter 220 causes a low voltage to be
applied to flip flop input 212b, causing motor 106 to reverse
the direction of movement of piston 105.
Movement of piston 105 is stopped when the voltage
of input connection 225c of flip flop 225 falls to a low
level. As previously discussed, this occurs if STOP switch
is closed or if the voltages at either points 231a or 231b
falls to a low level. If one of these three events occurs,
the voltage of output 225d of flip flop 225 and thus the
voltages of inputs 215b and 216b of nand gates 215 and 216
change to low voltage levels, in effect taking control of
switches 202b and 205b away from flip flop 212 --that is,
since inputs 215b and 216b are at low voltage levels, outputs
215c and 216c of nand gates 215 and 216 are at high voltage
levels regardless of the voltage levels of nand gate inputs
215a and 216a. Current is prevented from passing through
either coil 202a and 205a, and both switches 202b and 205b
are open. Motor 106 is deactivated, and piston 105 is
stopped in cylinder 102.
As will be understood by those of ordinary skill in
the art, any suitable voltage sources may be used for El-E12,
and these voltage sources may all be connected to one primary
source. With the preferred embodiment of circuit 200, the
logic devices used in the circuit require that sources El-E12
~Z~3~2Z9
-36-
l each provides a +5 DC voltage potential, although circuit 200
may be modified to use voltage sources of a diferent
magnitude. Also, suitable energy sources (not shown) are
provided for the electronic elements of circuit 200 including
flip flops 212 and 225, inverters 217 and 220, Nana gates
215, 216 and 235, and comparator 240.
3o
