U.S. patent number 3,634,039 [Application Number 04/886,875] was granted by the patent office on 1972-01-11 for blood testing machine.
Invention is credited to Thomas L. Brondy.
United States Patent |
3,634,039 |
Brondy |
January 11, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
BLOOD TESTING MACHINE
Abstract
A portable blood testing machine causes a blood sample to be
drawn from a patient and performs a preselected number of different
tests on the blood sample. The machine includes a suction device
for drawing the blood sample from the patient into the machine, an
input control device for determining the amount of the blood
withdrawn, a pair of electrically energized electrodes for
coagulating the blood, a dialyzer for separating the blood serum
from the blood solids and a device for automatically diverting the
serum into a preselected number of testing components which test
the serum by means of laser spectroscopy.
Inventors: |
Brondy; Thomas L. (Oak Park,
IL) |
Family
ID: |
25389974 |
Appl.
No.: |
04/886,875 |
Filed: |
December 22, 1969 |
Current U.S.
Class: |
422/73; 141/130;
356/318; 356/39; 422/81 |
Current CPC
Class: |
G01N
35/00 (20130101) |
Current International
Class: |
G01N
33/483 (20060101); G01N 35/00 (20060101); G01n
031/00 (); G01n 033/16 (); G01n 001/18 () |
Field of
Search: |
;23/253,259,230,23B
;424/11 ;73/423,425.4 ;356/39,85 ;141/130 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wolk; Morris O.
Assistant Examiner: Serwin; R. E.
Claims
What is claimed is:
1. Apparatus for making a plurality of tests on a blood sample,
comprising
a plurality of testing units for holding respective amounts of
blood on which said plurality of different blood tests are to be
performed,
manually operable selecting means for preselecting a plurality of
said tests to be performed,
pumps means for transferring a blood sample into said
apparatus,
control means responsive to said selecting means for controlling
the operation of said pump means to supply a predetermined amount
of blood for the preselected tests, and
diverting means responsive to said selecting means for directing
predetermined amounts of said blood sample into the selected ones
of said testing units for making the selected ones of said
tests.
2. Apparatus according to claim 1, further comprising
a line connected between said pump means and said diverting
means,
a pair of electrically energized electrodes mounted in proximity to
said line for producing an electric field in a portion of the blood
contained in said line, and
means for separating the blood serum from the blood solids after
the passage of said blood through said line,
whereby coagulation and separation of said blood is accelerated by
said electric field.
3. Apparatus according to claim 1, wherein said testing means
includes combining means for combining chemical reagents with said
blood serum for testing purposes.
4. Apparatus according to claim 1, wherein said control means
includes valve means for controlling the flow of blood to be drawn
into said apparatus, and timing means responsive to said selecting
means for maintaining said valve means in an open position for a
length of time proportionate to said number of preselected
tests.
5. Apparatus according to claim 4, wherein said valve means
comprises a spring-loaded needle valve, and said timing means
includes a timing belt having a gear tooth for cooperating with
said needle valve to permit said needle valve to move into its open
position and to maintain it in its open position for said length of
time, said tooth moving said needle valve into its closed position,
an electrical motor for driving said timing belt, said selecting
means including a plurality of manually operated electrical
switches for selectively connecting a plurality of impedances in
circuit with said motor, whereby said impedances control the speed
of the motor so that the motor in turn controls the speed of the
timing belt in accordance with the number of switches being
operated.
6. Apparatus according to claim 1, wherein said suction means
includes a flexible tube connected in fluid communication with said
control means and roller means extending transversely of said tube
for compressing a portion of said tube and for rolling along said
tube to remove the air therefrom so that the blood sample is drawn
into said tube.
7. Apparatus according to claim 6, further including a second tube
connected in fluid communication with said input device, said
roller means including a roller extending transversely of said
tubes for compressingly engaging said tubes, and motive means for
moving said roller along said tube to remove air from said tubes,
further including clamping means for alternately clamping a portion
of the first-mentioned tube and a portion of said second tube, said
clamping means normally closes a portion of the second tube to
cause the blood sample to be drawn from said input control device
to said second tube, whereby when said clamping means releases the
second tube and closes a portion of the first-mentioned tube, the
blood samples enters the second tube.
8. Apparatus according to claim 1, wherein said diverting means
includes a diverting valve, a plurality of passageways connecting
said diverting valve with said testing means, and means responsive
to said selecting means for normally blocking said passageways and
for selectively opening preselected ones of said passageways in
response to said selecting means being operated to preselect a
number of different tests.
9. Apparatus according to claim 8, wherein said testing units
include a plurality of combining units, each of said units
including a combining chamber adapted to be connected in fluid
communication with a source of chemical reagent, a tube
communicating with one of said passageways, a vacuum-operated
piston slidably mounted in the tube for determining a preselected
amount of said blood and for forcing the determined amount of blood
into said chamber to form a blood mixture, and a convoluted tube
connected in fluid communication with said chamber.
10. Apparatus according to claim 9, wherein said testing means
includes a plurality of readout units individually associated with
said combining units, each of said testing units including a
chamber connected in fluid communication with a corresponding
convoluted tube of a corresponding combining unit, a spring-loaded
piston having a semipermeable head slidably mounted in the
last-mentioned chamber for filtering the blood mixture, a
transparent curvette connected in fluid communication with the
last-mentioned chamber, and optical means for acting upon the
filtered blood mixture for test purposes.
11. Apparatus for separating blood serum from a blood sample,
comprising;
a pair of electrically energized electrodes adapted to be connected
to a source of electrical energy for coagulating the blood to clot
the blood solids in the blood serum, and
a dialyzer for separating the blood serum from the blood
solids.
12. Apparatus according to claim 11, wherein said electrodes are
composed of platinum, and further including a capacitor connected
across said electrodes.
Description
The present invention relates to a blood testing machine, and it
more particularly relates to a machine which performs a plurality
of different tests on a blood sample.
Medical doctors of today make use of many different techniques for
diagnosing and controlling disease. One such technique is blood
analysis, which has become more important with the advent of the
modern hospital laboratory and the extensive research into human
biochemistry. However, even though sophisticated procedures and
apparatus have been developed for analyzing blood, the problem
still remains of unwanted delays in obtaining the results of the
blood tests. Thus, it would be highly desirable to have a machine
for quickly and efficiently analyzing a patient's blood in the
patient's room, thereby eliminating the time delay in transporting
a blood sample to the hospital laboratory for analysis by the
ordinarily overworked laboratory technicians. Also, it would be
highly desirable to have such a machine which could repeatedly draw
blood from a patient without repeated venepunctures and their
accompanying trauma to the patient. In this regard, a needle
portion of the input device to the machine would remain intravenous
for as long as the physician deems necessary. In this way, a
nonlaboratory attendant, such as a nurse, could repeatedly operate
such a machine to test a patient's blood periodically, whereby the
nurse would be alerted to any change in the patient's condition and
thus be forewarned of an oncoming crisis, such as a heart attack.
Moreover, it would be desirable to have such a machine which would
be small in size and portable in nature, so that it could be used,
if desired, in a vehicle, such as an ambulance.
Therefore, it is the principal object of the present invention to
provide a new and improved blood testing machine.
It is further object of the present invention to provide a new and
improved blood testing machine which can quickly analyze a
patient's blood in the patient's room.
Another object of the present invention is to provide a new and
improved blood testing machine which remains intravenous for as
long as the treating physician deems necessary and which causes a
blood sample to be drawn from the patient so that the machine can
perform a plurality of different tests on the blood sample.
A further object of the invention is to provide a new and improved
technique for separating blood serum from a blood sample.
Briefly, the above and further objects are realized in accordance
with the present invention by providing a blood testing machine
which draws a blood sample into the machine and performs a
plurality of different tests on the blood sample. The machine of
the present invention includes a suction device which causes the
blood sample to be drawn into the machine, an input control device
for determining the amount of blood withdrawn in proportion to the
number of tests to performed, a pair of electrically energized
electrodes for coagulating the blood, a dialyzer for separating the
blood solids from the blood serum, a device for automatically
diverting the serum into a preselected number of testing components
which test the serum by techniques, such as laser spectroscopy.
The invention, both as to its organization and method of operation,
together with further objects and advantages thereof will best be
understood by reference to the following detailed description taken
in connection with the accompanying sheets of drawings,
wherein:
FIG. 1 is an elevational view, with portions thereof broken away
for illustration purposes, of the blood testing machine of the
present invention;
FIG. 2 is an enlarged, face view of the control panel for the
machine of FIG. 1;
FIG. 3 is a cross-sectional, enlarged view of the left-hand side of
the input control device for the machine of FIG. 1;
FIG. 4 is an enlarged, plan view in cross section of the input
control device of FIG. 1 taken substantially along the line 4--4
thereof;
FIG. 5 is a fragmentary, cross-sectional view of a porting on the
right-hand side of the input control device of FIG. 4 taken
substantially along the line 5--5 thereof;
FIG. 6 is an enlarged, fragmentary detail view in cross section of
the input control device of FIG. 4 taken substantially along the
line 6--6 thereof;
FIG. 7 is an enlarged, plan view in cross section of the front end
portion of the machine of FIG. 1 taken substantially along the line
7--7 thereof;
FIG. 8 is an enlarged elevational view in cross section of the
front end portion of the machine of FIG. 1 taken substantially
along the line 8--8 thereof;
FIG. 9 is an enlarged, cross-sectional view of the machine of FIG.
1 taken substantially along the line 9--9 thereof;
FIG. 10 is an enlarged, elevational view in cross section of the
dialyzer and main vacuum pump components of the machine of FIG.
1;
FIG. 11 is an enlarged, cross-sectional view of the dialyzer of
FIG. 10 taken substantially along the line 11--11 thereof;
FIG. 12 is an enlarged view of the machine of FIG. 1 taken
substantially along the line 12--12 thereof;
FIG. 13 is a plan view of the diverter and combiner components of
the machine of FIG. 1;
FIG. 14 is an enlarged, cross-sectional fragmentary view of the
diverter component of FIG. 13 taken substantially along the line
14--14 thereof, portions of the diverter component being enlarged
to a greater extent than other portions for illustration
purposes;
FIG. 15 is an enlarged, cross-sectional view of the rod release
mechanism of FIG. 1 taken substantially along the line 15--15
thereof;
FIG. 16 is an enlarged, perspective view of a member of the
diverter of FIG. 14;
FIG. 17 is a fragmentary, enlarged view in vertical cross section
of the combiner and readout components of the machine of FIG.
1;
FIG. 18 is a reduced-scale fragmentary plan view of the vacuum
release mechanism of FIG. 17;
FIG. 19 is a schematic drawing of the control circuitry for the
machine of FIG. 1; and
FIG. 20 is an enlarged cross-sectional view of another readout
component constructed in accordance with the present invention.
Referring now to the drawings, and more particularly to FIG. 1
thereof, there is shown a blood testing machine 10 which embodies
the principles of the present invention. The machine 10 generally
comprises an input control device 12 which has a tubular needle 14
for inserting into the vein of a patient, and a portable unit 16
which includes suction and testing components for drawing a blood
sample into the unit 16 and for subjecting the blood sample to a
plurality of different preselected tests. The portable unit
includes a suction and converter component 18, a dialyzer component
20, a main vacuum component 22, a diverter and combiner component
24, a readout component 26, a laser component 28, and a control
unit 30. A tube 31 connects the input control device 12 to the
portable unit 16 to convey the blood sample directly from the
patient's vein to the unit 16 for testing purposes. However, it is
to be understood that, if desired, the blood sample need not be
taken directly from the patient's vein, and that the sample may
instead be taken in the conventional manner and then drawn into the
machine 10 via the needle 14 of the input control device 12. A tube
33 connects a bottle 35 containing a proteolytic cleaning fluid,
such as acetone, to the input control device 12 for conveying the
cleaning fluid through the system during a cleaning cycle of
operation, which immediately follows a blood testing operation.
Referring now to FIGS. 1, 7, 8 and 9, in order to draw a blood
sample from the patient via the input control device 12 and the
tube 31 into the unit 16, the tube 31 is connected in fluid
communication at a Y-junction 37 to a pair of tubes 39 and 41,
which are relatively larger in diameter than the diameter of the
tube 31, and a roller 43, which is mounted on a carriage 45,
extends transversely across both of the tubes 39 and 41 and
compresses them as the carriage 45 moves the roller 43 along the
tubes 39 and 41 to evacuate the air therefrom. The volume of the
tube 39 is slightly greater than the volume of the tube 31 to cause
the blood sample to be drawn from the needle 14 of the input
control device 12 to the junction 37. The tube 41 is longer than
the tube 39 and has a volume which is sufficiently large to cause
the blood sample to be drawn through the component 18 and into the
dialyzer component 20. As best seen in FIG. 8, a piston-cylinder
operated clamp 47 located near the junction 37 of the tube 31
alternately compresses one and then the other of the tubes 39 and
41. The clamp 47 normally compresses the tube 41, and thus the tube
39 causes the blood sample to be drawn from the patient into the
tube 31 via the input control device 12. When the blood sample
reaches the junction 37, the clamp 47 automatically switches to
compress the tube 39 and open the evacuated tube 41 so that the
blood sample enters the tube 41, which at its opposite end is
connected in fluid communication with the dialyzer component
20.
A pair of platinum electrodes (not shown) are located in the
interior of the tube 71 near the entrance to the dialyzer component
20 and are electrically energized to cause the blood to be
coagulated so that the blood solids can be separated from the blood
serum by the dialyzer component 20. If desired, additional pairs of
electrodes may also be provided in the tube 41 and arranged in a
spaced-apart manner to ensure uniform clotting of the blood. The
electrodes traumatize the blood, and thus a clotting mechanism of
the blood is triggered in the same manner that a wound triggers the
clotting mechanism. It is to be understood that other devices as
well can be used to separate the blood serum from the blood
solids.
As best seen in FIGS. 1, 9, 11 and 12, a tube 49 is connected in
fluid communication with the dialyzer component 20 to convey the
unnecessary solid or cellular portion of the blood sample from the
dialyzer component 20 and extends (FIG. 11) longitudinally along
the component 18 above the tube 41 to a point (FIG. 1) almost
midway between the ends of the component 20, at which point the
tube 41 bends (FIG. 9) and extends through an opening in the rear
wall of the component 20 and extends (FIG. 12) along the outside of
the backwall of the component 20 to a waste bottle 51 which rests
on the top wall of the component 22. In order to draw the
unnecessary cellular portion of the blood sample from the dialyzer
component 20, carriage 45 rolls along and compresses the tube 49 as
the carriage 45 returns to its initial position near the clamping
device 47, whereby a vacuum is created in the tube 49 to draw the
waste material from the dialyzer component 20. For the purpose of
drawing the waste material along the tube 49 which extends along
the outside of the component 20, a tube 53 is connected in fluid
communication to the bottle 51 and extends from the bottle 51
across the top of the dialyzer component 20 through an opening in
the top wall of the component 18 and extends the length thereof
above the tube 39. Thus, the carriage 45 compresses the tube 53 and
thus causes a vacuum to be formed therein to evacuate the waste
bottle 51, whereby the waste material is drawn into the bottle
51.
A tube 55 is connected to the serum outlet of the dialyzer
component 20 to convey the serum from the dialyzer component 20 to
the diverter and combiner component 24 under the control of the
main vacuum component 22. The diverter portion of the component 24
diverts the blood sample into a number of different combining
chambers in accordance with the number of tests to be performed.
Chemical reagents are automatically added to the blood serum in
each of the combining chambers. The readout component 26 receives
the mixtures of serum and reagents and filters the mixtures. The
filtrates are subjected to laser spectroscopy by means of laser
beams from the laser component 28 to produce secondary radiations
which are then graphically displayed on a graph (not shown), which
may be an integral part of the blood testing machine 10 or which
may be a separate component. The intensity of the secondary
radiation from each of the filtrates closely follows "Beer's Law,"
and thus is proportional to the concentration of the blood
component being tested.
In operation, an ON-OFF switch 57 located on a control panel 59
(FIG. 2) is switched to its ON position to commence the operation
of the machine 10. The needle 14 is inserted into the vein of the
patient, and the attendant then selects the test or tests to be
performed on the patient's blood by pushing one or more of the
series of 10 different selection buttons 60, which are arranged in
a circle on the test panel 59. Once the machine 10 is thus
programmed, a start button 62 located at the top of the dialyzer
component 20 is pushed to initiate a cycle of operation. Thus, the
blood is drawn from the patient through the needle 14 and the input
control device 12 via the tube 31 into the component 18. After the
blood sample is drawn and leaves the device 12, cleaning fluid from
the bottle 35 via the tube 33 is drawn through the input control
device 12 into the tube 31, so that the cleaning fluid can follow
the blood sample through the various components of the machine 10
for cleaning purposes.
As the blood sample reaches the junction 37 at the end of the tube
31, the clamping device 47 switches to compress the tube 39 and
open the tube 41, whereby the blood sample enters the evacuated
tube 41. The blood sample is then subjected to the pair of
electrically energized electrodes in the tube 41 to coagulate the
blood sample. The blood serum is then separated from the solid
portion of the blood sample by means of the dialyzer component 20
and conveyed via the tube 55 to the diverter and combiner unit 24.
The blood serum sample is then diverted into a preselected number
of combining chambers in accordance with the number of tests to be
performed, and the necessary chemical reagents are combined with
the blood serum in the combining chambers to form precipitates. The
precipitates are then filtered out and analyzed by laser
spectroscopy, the results being displayed graphically.
Considering now the input control device 12 in greater detail with
reference to FIGS. 3, 4, 5 and 6, of the drawings, the device 12
includes an elongated hollow housing member 66, a nose member 68
which is welded to the member 66 by a peripheral weld 70, and a
housing 72 mounted on the side of the member 66. The device 12 is
composed of a suitable metal, but it may also be molded of a
suitable plastic material. A pair of U-shaped strap holders 74 and
76 are connected respectively to the member 66 and the housing 72
for the purpose of receiving and retaining a strap (not shown) so
that the device 12 can be held in place on the patient. At least a
portion of the device 12 is intended to be a disposable item so
that a fresh sterilized unit can be used for each patient.
As best shown in FIG. 3, a passageway 78 in the nose member 68
communicates with a passageway 81 which extends the length of the
upper portion of the member 66 and which is connected in fluid
communication with the tube 31 to convey the blood sample from the
needle 14 to the tube 31. A passageway 83 in the lower portion of
the member 66 extends the length of the member 66 and communicates
with the passageway 78 in the nose member 68 to convey the cleaning
fluid from the tube 33 to the passageway 78 and thus to the
passageway 81 and the tube 31. A connector 83 extends from the
front end of the nose member 68 for sealably receiving an enlarged
hollow end portion 87 of the hollow needle 14 to connect the needle
14 in fluid communication with the passageway 78 in the nose member
68. A ball valve 89 is located in the nose member 68 in the
junction between the passageway 78 and the passageway 81 to permit
the blood sample and the cleaning fluid to flow from the passageway
78 into the passageway 81, but fluid cannot flow from the
passageway 81 into the passageway 78, whereby fluids are prevented
from entering the vein of the patient. A ball valve 91 is disposed
in the nose member 68 at the junction between the passageway 78 and
the passageway 83 to permit the cleaning fluid to flow from the
passageway 83 into the passageway 78, and the ball valve 91 also
prevents the blood sample from entering the passageway 83.
A needle valve 93 includes a thin plastic rod 94 which extends
through an opening in the member 66 and into the passageway 78 of
the nose member 68, and which in its closed position extends into
the interior of the needle 14 and extends out the point of the
needle by a slight distance to prevent any blood from entering the
needle. As shown in FIG. 3, when the valve 93 is open, the rod 94
of the needle valve 93 is retracted so that its distal end is
located in the passageway 78 to permit the blood sample to flow
into the passageway 78. A block 98 is connected to the rear end of
the rod 94 to control the movement of the rod 94 and is slidably
mounted in a bore 101 in the member 66. The needle valve 93 also
includes a spring 103 which is located in the bore 101 and biases
the block 98 away from the front end of the housing member 66 to
cause the needle valve 93 to the biased in its open position. A rod
98A extends from the rear end of the block 98 through a central
hole in a removable retainer 104, which is threaded into the rear
end of the housing member 66, and when the needle valve 93 is
disposed in its open position, the rod 98A compressingly engages
the tube 33 to shut off the tube 33 so that the cleaning fluid is
prevented from entering the passageway 83 unless and until the
valve 93 is moved out of its open position.
In order to close the needle valve 93, as best shown in FIG. 4, a
pair of rods 105 and 106 are connected to and extend from opposite
sides of the block 98 through the respective elongated openings 107
and 108 in the housing member 66. A timing device generally
indicated at 109 in the housing 72 normally maintains the needle
valve 93 in its closed position against the force of the spring 103
as shown in FIG. 5, but the device 109 permits the needle valve 93
to snap back to its open position at the beginning of a testing
cycle of operation. The device 109 closes the needle valve 93
against the force of the number of tests to be performed. In this
regard, the needle valve 93 remains in its open position for a
period of time which is proportionate to the number of
test-selecting buttons 60 which are selected and depressed by the
attendant. For this purpose, a direct-current electric motor 111
which is disposed within the housing 72 drives a timing belt 113.
As shown in FIG. 5, the valve 93 is disposed in its closed
position, and a gear tooth 115 on the belt 113 engages the rod 105
and maintains the rod 105 in its extreme frontmost position during
the interval of time in which the needle valve 93 is closed.
However, once the machine 10 is programmed by depressing the
buttons 60 and the start switch 62 is depressed, the electric motor
111 drives the timing belt 113 in a counterclockwise direction as
seen in FIG. 5 so that the gear 115 is cammed away from the rod 105
to permit the block 98 to snap back to its normal position as seen
in FIGS. 3 and 4. The motor 111 is driven at a rate of speed which
is inversely proportionate to a number of selection buttons 60
which have been selected and depressed. In other words, with a
greater number of depressed buttons 60, the motor 111 drives the
timing belt 113 at a correspondingly slower speed, whereby the
valve 93 remains open for a proportionately longer time to withdraw
a proportionately greater amount of blood from the patient. Once
the gear tooth 115 commences its forward motion, the tooth 115
engages the rod 105 to move it in a forward direction against the
force of the spring 103. A switch 117 is engageable by the lower
end portion of the gear tooth 115 to cause the motor 111 to
abruptly stop the timing belt 113 once the valve 93 reaches its
closed position. The gear 115 normally maintains the block 98 in
its extreme forward position, thereby to maintain the needle valve
93 in its closed position.
A drive shaft 119 of the motor 111 and a capstan or sleeve 120
surrounding and fixed to the drive shaft drives the timing belt 113
which is wrapped about and stretched between the capstan 120 and
another capstan 121 which is rotatably mounted on a stub shaft 123.
In order to permit the rod-engaging portion of the tooth 115 to
readily move past the capstan 121, as shown in FIG. 6, the capstan
121 has a depressed or reduced portion 125, which receives the
tooth 115 as it moves past the capstan 121. The capstan 120 has a
similar depressed portion (not shown) to permit the rod-engaging
portion of the tooth 115 to pass by the drive shaft 119. The
electrical connections for the motor 111 and a pair of wires 126
for the switch 117 are connected to the control unit 30 via a cable
127.
Considering now the clamping device 47 in greater detail with
reference to FIGS. 1, 7 and 8 of the drawings, the clamping device
47 includes a lever 120 which is pivotally mounted at 122 and
extends transversely over the tubes 39 and 41 which are disposed on
opposite sides of the pivot point 122. A spring 124 is connected to
an end 125 of the lever 120 to bias it into compressing engagement
with the tube 41 to shut off the tube 41, the tube 39 on the
opposite side of the pivot point 122 being normally in an open
condition. A piston cylinder assembly 126 has a piston rod 127
which is connected to an opposite end 129 of the lever 120 to pivot
the lever 120 in a clockwise direction as seen in FIG. 8 until the
lever 120 compressingly engages the tube 39 to shut off the tube 39
and to open the tube 41.
Considering now the suction and converter component 18 with
reference to FIGS. 1 and 9 of the drawings, the tubes 39 and 41 are
supported by the respective horizontal spaced-apart, coplanar
plates 131 and 133 which extend from and are supported by the
respective vertical sidewalls 135 and 137 of the component 18. A
pair of horizontal, coplanar spaced-apart plates 139 and 141 are
supported by the respective sidewalls 135 and 137 and are disposed
above the plates 131 and 133, respectively, to cause the roller 43
to compressingly engage the tubes 39 and 41 as the roller 43 moves
toward the dialyzer component 20, whereby the roller 43 rolls along
the tubes 39 and 41 and compresses them. The carriage 45 includes a
triangularly shaped plate 142 which has a backwardly sloping guide
slot 143 through which extends a reduced portion 145 of the roller
43 so that when the carriage 45 moves in a direction away from the
dialyzer component 20, the roller 43 is permitted to roll along the
upper surfaces of the plates 139 and 141 whereby to compress the
upper tubes 49 and 53 against a top wall 147 of the component 18.
As shown in FIG. 1, a downwardly turned end portion (not shown) of
the plate 141 near the component 20 cause the roller 43 to be
guided upwardly when the carriage 45 reverses its direction of
movement and moves away from the component 20 to position the
roller above the plates 139 and 141.
A gear 152 is rotatably connected to the plate 142 of the carriage
45 by means of a rivet 154. A pair of vertically spaced racks 156
and 158 extend for the length of the component 18 and mesh with the
gear 152, whereby the carriage can roll along the racks 156 and
158. The rack 156 is connected to the underside of the plate 133,
and the rack 158 is connected to a bottom wall 160 of the component
18. A direct-current electric motor 162 is mounted on the carriage
plate 142 and drives the gear 152 by a suitable gear train (not
shown).
As shown in FIG. 1, a limit switch 164 is supported by the plate
133 near the end of the tube 39 and is actuated by the carriage
plate 142 to cause the clamping device 47 to switch from its normal
position as the carriage 45 moves toward the dialyzer component 20
and rolls past the end of the tube 39. A switch 166 is supported by
the bottom wall 160 beyond the downwardly turned end portion 149 of
the guide plate 133 so that when the carriage plate 142 actuates
the switch 166, it causes a reversal of electrical power to the
electric motor 162 thereby to reverse the direction of movement of
the carriage 45.
Referring now to FIGS. 1, 10, 11 and 12, the start button 62
comprises a rod 172 which is spring-loaded at its bottom end by
means of a coil spring 174 (FIG. 10) and which has an electrical
switch 62A mounted on the top wall of the component 20 and actuated
by the rod 172 to start a cycle of operation. In order to retain
the rod 172 in its depressed condition, a catch member 176, which
is a rod bent in the shape of a rectangle, is urged into engagement
with the rod 172 by means of a pair of springs 178 and 179 (FIG.
11) stretched between the respective rings 181 and 183 of the
respective side portions 185 and 187 of the catch member 176 and an
end wall 189 of the component 18. A notch 191 in the rod 172
receives an end portion 193 of the catch member 176, when the rod
62 is depressed, to maintain the rod 172 in its depressed
condition. As shown in FIG. 1, when the carriage 45 returns to its
original position, an opposite end portion 195 of the catch member
176 is moved by the carriage plate 142 of the carriage 45 to move
the end portion 193 of the catch member 176 out of engagement with
the notch 191 to permit the spring 174 to return the rod 172 to its
initial position. Thus, the carriage plate 142 moves the catch
member 176 to cause the switch 62A to turn off the power to
abruptly stop the carriage 45. As a result, the carriage 45 comes
to rest at a position where the roller 43 is located beyond the end
portion of the guide plates 139 and 141 near the sidewall 170 so
that the roller then returns to its normal position in the lower
end of the slot 143 in the plate 142. When the start button 62 is
depressed to start a cycle of operation, the bottom 62 must be held
in a fully depressed condition until the carriage 45 begins to move
toward the dialyzer component 20 to permit the catch member 176 to
move into engagement with the notch 191. In order to slidably mount
the catch member 176, the side portions 185 and 187 of the catch
member 196 are slidably supported by a plurality of the respective
brackets 197 and 199 which are supported by the top wall 147 of the
component 18.
Considering now the dialyzer component 20 is greater detail, with
reference to FIGS. 1, 10 and 11 of the drawings, the component 20
separates the clotted blood from the blood serum so that the blood
serum can be subjected to the desired tests. It should be
understood that, if desired, rather than utilizing the electrodes
and the dialyzer component 20, the blood serum may be obtained
directly by separating the blood serum from the unnecessary
cellular blood solids by conventional means. A ball check valve 200
is disposed in the tube 41 which is connected to an inlet 202 of a
dialyzer unit 204 for separating the clotted blood solids from the
blood serum. The ball check valve 200 permits the clotted blood to
enter the dialyzer unit 204 and prevents any flow of fluid in the
reverse direction. Thus, the check valve 200 prevents partially
clotted blood from flowing back toward the input control device 12
and thus the patient. The dialyzer unit 204 includes a helical
semipermeable tube 205 which is connected in fluid communication
between the inlet 102 and an outlet 206, and a tube 208 which
concentrically and sealably surrounds the semipermeable tube 205.
The tube 208 is connected in fluid communication with an outlet 210
which in turn is connected in fluid communication with the tube 55.
The suction tube 55 draws the blood serum through the semipermeable
tube 205 into the concentric tube 208 and out the tube 55, whereby
the blood serum id drawn from the dialyzer component 20 and is
transferred to the component 24. The larger unnecessary cellular
portion of the blood does not pass through the semipermeable tube
208, but instead it is conveyed to the tube 49 via a ball check
valve 212 which permits the cellular portion of the blood to leave
the dialyzer unit 204 and prevents a reverse flow the cellular
portion of the blood from the tube 49 to the dialyzer unit 204.
The unnecessary cellular portion of the blood sample is drawn from
the dialyzer unit 204 into the evacuated tube 49 as a result of the
roller 43 compressing the tube 49 and forcing the air therefrom. In
order to draw the cellular portion of the blood from the tube 49 to
the waste bottle 51, the roller 43 also compresses the longer tube
53 to force the air therefrom and thus to withdraw the air from the
bottle 51, which is connected in fluid communication with the tube
53.
Considering now the main vacuum component 22 in greater detail with
reference to FIG. 10 of the drawings, the main vacuum unit 22
supplies the necessary vacuum to draw the blood serum from the
dialyzer component 20 to the diverter component 24 and the readout
component 26. Since the blood serum is not as unstable as whole
blood, the suction produced by the main vacuum component 22 need
not treat the blood serum as gently as the suction component
treated the whole blood. Moreover, if desired, a conventional
vacuum pump may be used in place of the component 22.
As shown in FIG. 1, the vacuum pump component 22 includes a plunger
214 which extends into the component 18. In FIG. 1, the plunger 214
is shown in the normal position, and it is shown in its fully
retracted position in FIG. 10. The plunger 214 is moved from its
normal position to its retracted position by the carriage plate 142
to activate the vacuum pump component 22. One end of a hollow
piston rod 216 is connected to an end plate 218 of the plunger 214,
and the opposite end of the hollow piston rod 216 is connected to a
piston head 221 which is slidably mounted within an elongated
chamber 223. A return spring 225 is positioned between the end
plate 218 of the plunger 214 and the vacuum chamber 223 to bias the
plunger 214 to its normal position, as shown in FIG. 1, the spring
225 causing the plunger 214 to move extensively toward the left as
seen in FIG. 1 as the carriage 45 returns to its initial
position.
A ball valve 229 is positioned in the hollow rod 216 at an opening
in the end wall of the piston head 221 to permit air to flow from
the interior of the chamber 223 into the hollow piston rod 216 and
enter the atmosphere via a vent 231 in the portion of the piston
rod 216 extending outside of the chamber 223. Thus, as the plunger
214 retracts due to the carriage 45, a tube 223 which is connected
in fluid communication between the evacuated chamber 223 and other
components of the machine 10 via a ball check valve 235, provides
the necessary suction to draw the blood serum through the remaining
components to the readout component 26. The valve 235 prevents air
from entering the interior of the evacuated chamber 223 and permits
air to escape during the initial movement of the piston head 221 to
evacuate the chamber 223.
In order to energize the diverter component 24 to receive the blood
serum, a toggle switch 236 is actuated by an abutment 236b as the
plunger 214 is moved to its retracted position, and the switch 236
is opened by an abutment 236a during the return of the plunger 214
to its initial position.
Considering now the diverter component 24 in greater detail with
reference to FIGS. 1, 13, 14, 15 and 16, the selection buttons 60
each include a rodlike extension 237 (FIG. 1), which is similar to
the start button 62 and which extends into the diverter component
24 to control its operation. As best seen in FIG. 13, the diverter
component 24 includes a valve assembly 239 for conveying the blood
serum to a combining assembly 241 which surrounds the valve
assembly 239 and which comprises a plurality of individual
combining units 243. The diverter component further includes a
plurality of individual valve units 245, which are controlled by
the rods 237, for selectively connecting the valve assembly 239 in
fluid communication with the combining units 243. The rods 237 are
reciprocably mounted in the valve units 245, and the upper ends of
the rods 237 project from the control panel 59 to provide the
selection buttons 60. The lower ends of the rods 60 extend into the
valve units 245.
As shown in FIG. 15, in order to retain the rods 60 in a depressed
position during a testing cycle of operation, there is provided an
electromagnetic release mechanism 247 having a plurality of
individual catchplates 249 which are slidably mounted on a
baseplate 250. A plurality of springs 252 extending between the
catchplates 249 and a plurality of electromagnets 254 bias the
catchplates 249 against the rods 237. A plurality of slots 256 in
the rods 237 receive the catchplates plates 249 when the rod is
moved into its downward position, whereby the catchplates 249
retain the depressed rods in their downward position. As best seen
in FIG. 14, a plurality of springs 258 surround the rods 237 above
the valve unit 245, and a plurality of springs 260 are disposed
within the valve units 245 at the bottom ends of the rods 237 to
bias the rods 237 in their upper position where the buttons extend
above the control panel, whereby when the magnets 254 are energized
to retract the catchplates 249 against the force of the springs
252, the springs 258 and 260 of the depressed rods 237 cause the
depressed rods to return to their upper initial position. It is to
be understood that the valve units 245 as illustrated in FIG. 14
are shown in an enlarged scale as compared to the valve assembly
239 and the selection and combining assembly 243.
The valve assembly 239 generally comprises a cylindrical housing
valve-seat member 262 which has a conical-shaped chamber 264, and a
conical-shaped valve member 266 which is urged via a compression
spring 268 into a closed position in the chamber 264 to seal an
inlet 271 which is connected in fluid communication with the tube
55. A plurality of passageways 275 are disposed below the valve
member 266 in a lower base portion 273 of the housing member 262
and communicate with the conical-shaped chamber 264 to convey the
blood serum from the tube 55 to a plurality of passageways 277
which are located in the housing member 262 and which are connected
in fluid communication with corresponding passageways 279 in the
valve units 245. A plurality of passageways 281 in the base portion
273 of the housing member 262 communicate with a tube 283 through a
centrally disposed hole 285 in the bottom of the housing member 262
so that suction can be applied from the main vacuum component via
the tube 283 to evacuate the chamber 275 when the valve member 266
is in its closed position. An electrical coil 287 is disposed in
the bore of the housing member 262 and is energized in response to
the switch 236 in the main vacuum component 22 to cause the valve
member 266 to move out of sealing engagement with the member 262
against the force of the bias spring 268 into contact with the
upper surface of the base portion 273. A plurality of ball check
valves 289 are disposed within the passageways 277 to permit the
blood serum to flow from the passageways 275 into the passageways
279 of the valve unit 245 and to prevent air from entering the
passageways 275 from the passageways 277 when the passageways 275
are evacuated via the tube 283.
Each of the rods 237 of the valve unit 245 includes a transverse
passageway or hole 290 which has the same diameter as the passage
way 279 or less, whereby when the rods are depressed, the depressed
rods 237 have their holes 290 aligned with the passageways 279 to
permit the fluid to flow from the valve assembly 24 to the combiner
unit 243 via a tube 292.
Considering now the valve units 245 in greater detail, each of the
units 245 includes a chamber 294 which has an inlet 296 and an
outlet 298 for receiving a chemical reagent to be added to the
blood serum for test purposes. A piston device 300 is connected to
and forms an integral part of the bottom end of each of the rods
237 for the purpose of forcing the chemical reagent from the
chamber 294 through the outlet 298. The piston device 300 includes
an upstanding cylindrical piston head 302 which is integrally
connected to a circular bottom wall 304 which in turn is biased in
an upward direction by the spring 260. The bottom wall 304 is
integrally joined to the rod 237 via a pair of diametrically
opposed rods 306 and 308 which are slidably mounted in their
respective holes in the housing of the valve unit 245. A pair of
diametrically opposed bars 311 and 313 are also connected to the
periphery of the bottom wall 304 and are positioned so that when
the rod 237 is disposed in its normal position, the bars 311 and
313 block and seal the serum passageways 279 in the valve unit 245.
A depressed rod therefore causes the piston head 302 to retract
almost entirely out of the chamber 274 to permit the chemical
reagent to enter the chamber 294 via the inlet 296. When the rods
237 are released by the release mechanism 247, the piston head 302
enters the chamber 294 and forces the liquid contained in the
chamber into the outlet 298.
Considering now the combining units 243 in greater detail with
reference to FIGS. 13, 17 and 18 of the drawings each of the
combining units 243 includes a combining chamber 315 for mixing the
blood serum with chemical reagents, a serum measuring device 317
connected in fluid communication with the tube 292 from the valve
unit 245 for measuring the amount of blood serum entering the unit
243 and for forcing the blood serum into the combiner chamber 315,
and a convoluted tube 319 connected in fluid communication with the
readout component 26 for additional agitation of the mixture of
blood serum and chemical reagents. The blood serum tube 292 enters
a housing 320 of the unit 243 and is connected in fluid
communication with the measuring device 317. A ball check valve 322
is disposed in the tube 2892 to prevent any of the blood serum from
leaving the unit 243 A tube 324 is connected in fluid communication
with the tube 292 between the check valve 232 and the device 317 to
transfer the blood serum from the tube 292 to the combining chamber
315. A ball check valve 326 is disposed within the tube 324 to
prevent the blood serum from leaving the combining chamber 315 via
the tube 324.
The device 317 includes a spring-loaded piston 328 in the tube 292
which is movable toward and away from a vacuum chamber 330. The
piston 328 is moved by a predetermined distance in a downward
position toward the chamber 330 as a result of the chamber 330
being evacuated by the main vacuum component 22. As the piston rod
328 retracts, a vacuum is created in the tube 292 to draw the blood
serum into the tube 292, it being understood that the ball check
valve 326 in the tube 324 prevents air from being drawn from the
combining chamber 315 into the tube 292. A spring-loaded
wedge-shaped plug member 332 is normally spring-biased in a closed
position to close and seal a vent opening in the bottom wall of the
chamber 330, and in order to release the vacuum in the chamber 330,
the plug 332 moves upwardly, whereby the spring-loaded piston 328
returns to its initial position to force the blood serum in the
tube 292 into the connecting tube 324 and thus into the combining
chamber 315.
As shown in FIG. 18, in order to move the wedge members 332 by a
short distance in an upward direction to vent the chambers 330, a
plurality of cam members 334 of an electromagnetic release
mechanism 336 are disposed opposite the wedge members 332 and are
slidably mounted on a baseplate 338. An electromagnet 340, when
energized, moves a plurality of shank portions 342 of the cam
members 334 toward the magnet 340 against the force of a plurality
of bias springs 344 to cause the wedge members 332 to momentarily
relieve the vacuum in the chambers 330. The springs 344 cause the
slidably mounted cam members 344 to return to their original
position.
A tube 346 is connected in fluid communication with the chamber 330
and extends through an opening in the housing 320 of the unit 243
and is connected to the pump component 22 via a distributor 348
which is connected to each of the units 243 and to the valve
assembly 239 via the tube 283. The pump component 22 is connected
to the distributor 348 via the tube 233.
A tube 350 extends through the component 243 and is connected
between a source (not shown) of chemical reagent under pressure and
the inlet 296 of the corresponding valve unit 245. A tube 352
connects the outlet 298 of the corresponding valve unit 245 to the
combining chamber 315. Should a second reagent be required, a
second inlet tube 354 is directly connected to the combining
chamber 315. For mixing purposes, a plurality of mixing vanes 356
are disposed within the combining chamber 315 which is supported by
a bracket 358 which in turn is connected to the housing 320.
Considering now the readout component 26, a plurality of outlets,
such as the outlet 358, of the convoluted tubes 319 are connected
in fluid communication with a plurality of chambers, such as the
chamber 361, in a plurality of readout units 363, it being
understood that there is a readout unit 363 for each combining unit
of the combining component 243. An outlet tube 365 is connected in
fluid communication with the tube 49 (FIG. 12) to convey the
remains of the blood serum to the evacuated waste bottle 51. A
transparent curvette 367 is connected in fluid communication
between the chamber 361 and the outlet tube 365. A piston assembly
369 is disposed in the chamber 361 and has a semipermeable piston
head 370 which is drawn into the curvette 367 by the vacuum in the
waste bottle 51 to cause the precipitates of the blood
serum-reagent mixture from entering the curvette 367. A spring 372
is connected between the head 370 and a perforated plate 374 to
retract the semipermeable head 370 from the curvette 367 to permit
the trapped precipitate particles to flow through the curvette 367
to the waste bottle 51 via the tube 365.
A pair of windows 376 and 378 on opposite sides of the curvette 367
are disposed in a passageway 381 in the housing 363 so that a laser
beam from the laser component 28 can be directed in the passageway
381 and thus the beam passes through the curvette 367. The windows
are composed of nearly nonrefractive quartz material. A beam enters
the passageway 381 before it enters the curvette 367 to establish a
reference. When the fluid enters the curvette 367, the beam
stimulates the specific quantity of material in the curvette 367,
since the curvette has a predetermined microvolume. With the
material in the curvette 367, the intensity of the secondary
radiation of the beam leaving the exit window 378 closely follows
Beer's Law, and thus is proportional to the concentration of the
blood component being tested, it being understood that different
valves of secondary radiation are produced for the various
different tests due to the fact that different reagents are added
to the blood serum. Moreover, it is to be understood that, if
desired, different types of readout components may be used in place
of the laser testing technique.
A photomultiplier tube 383 is positioned in the housing 363 in line
with the passageway 381 to detect the reference and secondary
radiation which passes through the passageway 381 and the curvette
367. The photomultiplier tube 383 in turn converts the radiations
into electrical energy to operate a stylus (not shown) for marking
a moving graph paper (not shown) in a conventional manner, the
conventional graphical recording apparatus not being illustrated in
the drawings. A magnet 385 and a light filter 387 are disposed
between the curvette 367 and the photomultiplier tube 383, and a
lens may be located between the magnet and filter cluster and the
photomultiplier tube 383.
When the ON-OFF switch 57 is first closed, the stylus records a
normal position on the graph to indicate an area of relatively
normal values for a particular blood component. When the material
enters the curvette 367, a change is indicated on the graph paper.
A switch 391 (FIG. 1) is actuated by the carriage 45 at its initial
position to energize a motor 394 (FIG. 19) to move the graph paper,
it being understood that there is one stylus for each readout unit
363 and that the graph paper is divided into 10 separate horizontal
test quadrants which are each calibrated for its specific test.
Referring now to FIG. 19 of the drawings, a control circuit 396 is
located in the control unit 30 and includes a pair of transformers
398 and 401 having their primary windings connected in series with
the ON-OFF switch 57 and an indicator lamp 403 on the control panel
59 and which are connectable to a source of AC electrical power by
means of a plug 405. A conventional rectifier circuit 407 is
connected across a secondary winding 409 of the transformer 398 to
rectify the output of the secondary winding 409 for the purpose of
driving the motors 111 and 162 which are coupled across the
rectifier circuit 407 between the terminals 411 and 413. The
terminal 413 is connected to the rectifier circuit 407 by means of
the start switch 62A. The motor 111 of the input control device 12
is connected via a wire 415 between the terminal 411 and a
resistance switching network generally indicated at 417, which in
turn is connected to a safety switch 419. A manually operable reset
switch 420 connects the safety switch 419 to the terminal 413 and
is operated at the control panel 59. The switch 420 is a single
throw, double pole switch, which in its normal position as shown in
FIG. 19, connects a lamp 421 across the terminals 411 and 413 to
indicate to the attendant that the reset switch 420 must be
actuated to its other position before commencing the operation by
closing the start switch 62A. In order to return the reset switch
420 to its initial position, a relay 420A is connected to a
secondary winding 422 of the transformer 398 via a rectifier
circuit 424 and is momentarily actuated by the switch 117 in the
input control device 12 to release the spring-loaded switch 420 to
cause it to return to its initial position.
The resistance switching network 417 comprises a plurality of
switches, such as the switch 426, which are single-throw, double
pole switches and which are manually operated by the rods 60 at the
control panel 59. Each of the switches connects a resistor, such as
a resistor 428, in series with the motor 111 to cause it to run at
a proportionately slower speed in proportion to the number of
closed switches. In this regard, the switch 426 in its normal
position opens the circuit to its resistor 428, but in its closed
position, the switch 426 connects the resistor 428 in series with
the motor 111. The safety switch 419 is mechanically connected to
each of the switches 426 of the network 417 so that when one or
more of the switches of the network 417 are closed, the switch 419
is then automatically closed. In this manner, the motor 111 cannot
be accidentally energized to cause blood to be withdrawn from a
patient since one or more of the switches of the network 417 must
first be actuated.
A secondary winding 431 of the transformer 398 is connected to the
electromagnet 126 of the clamping device 18 via a rectifier circuit
433 to energize the electromagnet 126 upon closing of the switch
164 which is located slightly beyond the end of the shorter tube 39
of the component 28. A rectifier circuit 435 is connected across a
secondary winding 437 of the transformer 398 to supply rectified
current via the switch 341 to the electromagnets 254 and 340, which
are connected in parallel. In this regard, when the switch 341 is
momentarily actuated by the carriage 45 in the component 28, the
switch 341 closes momentarily to energize momentarily the
electromagnets 254 and 340 whereby the release mechanism 247
releases the rods 237 and the release mechanism 340 causes the
vacuum to be relieved in the vacuum chambers 330.
A rectifier circuit 439 is connected across a secondary winding 442
of the transformer 398 to energize the electromagnet 287 of the
valve assembly 239. Connected in series with the electromagnet 287
is the switch 236 which is closed when the plunger 214 is fully
retracted and which is opened with the plunger 214 returns to its
initial position.
The pair of platinum electrodes, which are disposed in the tube 41
of the component 28, and which are shown schematically in FIG. 19
by the box E, are connected across a secondary winding 444 of the
transformer 401 via a capacitor 446 which is connected across the
winding 444 to supply low voltage and low current excursions to the
electrodes for traumatizing the blood for trigger the clotting
mechanism of the blood. For the purpose of supplying power to the
laser component 28, a secondary winding 448 of the transformer 401
is connected to the laser component 28 via a rectifier circuit 450.
A secondary winding 452 of the transformer 401 is connected to the
photomultiplier tubes 383 via a rectifier circuit 454 for the
purpose of energizing the photomultiplier tubes. In like manner,
the graph motor 394 is coupled to a secondary winding 456 of the
transformer 401 via a rectifier circuit 458, the graph motor being
energized by the switch 391 which is connected in series with the
motor 394 and which is energized by the carriage 45 of the unit
18.
Referring now to FIG. 20, there is shown another readout component
460, which is similar to the readout unit 26 of FIG. 17, and which
may be used in addition to or in place of the readout units 26. The
unit 460 may be used for different types of blood testing
procedures, such as where additional reagents are required. The
unit 460 includes a housing 462 which supports a cylinder 464
having an inlet 466 adapted to be coupled in fluid communication
with the outlet of a combining unit 243. A curvette 468 forms an
extension of the cylinder 464 and has an outlet 469 which is
connected to a combining chamber 471. A reagent tube 473 is also
connected in communication with the chamber 471 to provide a
passageway to permit the addition of other reagents. A convoluted
tube 475 is connected in fluid communication with a chamber 471 and
with a curvette 477 which is disposed in a laser-beam passageway
479. A pair of oppositely disposed windows 481 and 483 permit the
laser-beam to pass through the curvette 477. A tube 185 is
connected to the curvette 477 and to the vacuum waste bottle 51. A
ball check valve 487 and a spring-loaded semipermeable piston 489
are disposed within the cylinder 464 and the curvette 468 in the
same manner as the ball check valve 375 and the piston assembly 369
of FIG. 17. A photomultiplier tube 490 is positioned in the housing
462 at the end of the passageway 479 opposite the exit window 483
of the curvette 477 to receive the reference and secondary
radiation of the laser-beam and to convert the radiation into
electrical energy for operating the stylus of the graphic recording
apparatus. A filter 492 is disposed in the passageway 479 between
the window 483 and the photomultiplier tube 490.
In view of the foregoing description, it should now be apparent
that there is provided in accordance with the present invention a
new and improved blood testing machine which is capable of
performing a number of different tests simultaneously on a blood
sample. Moreover, the blood testing apparatus of the present
invention is adapted to automatically draw a blood sample from a
patient and divert it into the separate blood testing components of
the machine. Blood serum is clotted by electrically energized
electrodes, and then the unnecessary solid portion of the blood
sample is separated from the blood serum by a dialyzer.
While the present invention has been described in connection with a
particular embodiment thereof, it will be understood that many
changes and modifications of this invention may be made of those
skilled in the art without departing from the true spirit and scope
thereof. Accordingly, the appended claims are intended to cover all
such changes and modifications as fall within the true spirit and
scope of the present invention.
* * * * *