U.S. patent application number 13/742960 was filed with the patent office on 2013-05-23 for syringe infusion pump.
This patent application is currently assigned to NUMIA MEDICAL TECHNOLOGY, LLC. The applicant listed for this patent is Numia Medical Technology, LLC. Invention is credited to Eric John Flachbart, Cayle E. Waring.
Application Number | 20130129532 13/742960 |
Document ID | / |
Family ID | 40130068 |
Filed Date | 2013-05-23 |
United States Patent
Application |
20130129532 |
Kind Code |
A1 |
Flachbart; Eric John ; et
al. |
May 23, 2013 |
Syringe Infusion Pump
Abstract
One embodiment of the present patent application is a syringe
infusion pump that includes a syringe, a syringe barrel holder, and
a force sensor. The syringe includes a barrel and a plunger. The
plunger has a plunger axis and the barrel has a barrel axis and a
barrel diameter. The syringe is one of a plurality of syringes,
each having a different barrel diameter. The force sensor is
positioned for detecting a force along the barrel axis. The syringe
holder provides the barrel axis automatically aligned with the
force sensor for each syringe of the plurality of syringes.
Inventors: |
Flachbart; Eric John;
(Kirby, VT) ; Waring; Cayle E.; (Kirby,
VT) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Numia Medical Technology, LLC; |
Newport |
VT |
US |
|
|
Assignee: |
NUMIA MEDICAL TECHNOLOGY,
LLC
Newport
VT
|
Family ID: |
40130068 |
Appl. No.: |
13/742960 |
Filed: |
January 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12157477 |
Jun 11, 2008 |
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13742960 |
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60934236 |
Jun 11, 2007 |
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Current U.S.
Class: |
417/279 |
Current CPC
Class: |
A61M 5/1456 20130101;
A61M 2205/332 20130101; A61M 5/16854 20130101; F04B 9/02 20130101;
A61M 2209/082 20130101 |
Class at
Publication: |
417/279 |
International
Class: |
F04B 9/02 20060101
F04B009/02 |
Claims
1. A syringe infusion pump for use with a plurality of different
size syringes, each different size syringe having a different
syringe barrel diameter, and each of said plurality of syringes
including a plunger having a plunger axis received in the barrel
along a barrel axis, said pump comprising: a drive head including a
force sensor positioned to sense force applied to the plunger by
the drive head, the force sensor having a center; and a syringe
barrel holder configured to hold each of said syringe barrels of
different diameters in a fixed position with the barrel axis
aligned with said force sensor center for each different diameter
syringe barrel.
2. A syringe infusion pump as recited in claim 1, further
comprising a syringe plunger holder mounted on said drive head,
wherein said syringe plunger holder engages the plunger with said
plunger axis aligned with said force sensor center for each
different diameter syringe barrel.
3. A syringe infusion pump as recited in claim 2, wherein said
syringe plunger holder comprises a first plunger holder element and
a second plunger holder element, said first plunger holder element
being constrained to move a distance equal to a distance moved by
said second plunger holder element, but in an opposite
direction.
4. A syringe infusion pump as recited in claim 2, wherein: said
drive head is configured and dimensioned to push the plunger into
the barrel of each different size syringe; and said force sensor is
positioned to detect force exerted by said drive head on the
plunger.
5. A syringe infusion pump as recited in claim 4, wherein said
force sensor is fixed in said drive head, and said syringe plunger
holder engages the plunger with the plunger axis aligned with the
barrel axis.
6. A syringe infusion pump as recited in claim 1, wherein said
syringe barrel holder is configured and dimensioned to provide a
fixed position for the barrel axis with respect to said force
sensor center and said fixed position is independent of size of the
barrel for each different diameter syringe barrel.
7. A syringe infusion pump as recited in claim 1, wherein said
syringe barrel holder includes a barrel clamp comprising a first
element and a second element, said first element and said second
element being movable to engage and hold a syringe barrel in said
fixed position independent of the diameter of said barrel.
8. A syringe infusion pump as recited in claim 7, wherein said
first element is constrained to move a distance equal to a distance
moved by said second element, but in an opposite direction.
9. A syringe infusion pump as recited in claim 7, wherein said
barrel clamp further comprises: a first rack connected to the first
element and a second rack connected to the second element, said
racks having opposed toothed surfaces; a gear disposed between said
racks and meshing with each rack to control relative position of
said first and second elements with respect to one another; and a
biasing element forcing the clamp elements together.
10. A syringe infusion pump as recited in claim 9, wherein: said
barrel clamp further comprises a guide shaft secured to the first
clamp element and extending through said second clamp element; and
said pump further comprises a base, wherein the gear is disposed in
said base and said guide shaft extends into said base.
11. A syringe infusion pump as recited in claim 7, further
comprising a barrel diameter sensor positioned and configured to
detect a magnitude of separation between said first element and
said second element.
12. A syringe infusion pump as recited in claim 11, wherein said
barrel diameter sensor includes an absolute encoder for detecting
angular movement of said gear.
13. A syringe infusion pump as recited in claim 2, wherein said
syringe plunger holder comprises front and rear plunger clamps
cooperating to position the plunger with the plunger axis aligned
with the force sensor center independent of the diameter of the
barrel of a syringe held in the syringe barrel holder.
14. A syringe infusion pump as recited in claim 2, wherein said
syringe barrel holder is configured to hold the barrel with the
barrel axis aligned with the force sensor center in response to the
syringe plunger holder positioning the plunger with the plunger
axis aligned with the force sensor center.
15. A syringe infusion pump as recited in claim 1, further
comprising a processor and an alarm, wherein said force sensor is
connected to provide force data to said processor, and said
processor is programmed to activate said alarm if force applied
exceeds a specified value.
16. A syringe infusion pump as recited in claim 1, further
comprising a drive head position sensing mechanism.
17. A syringe infusion pump as recited in claim 16, wherein: said
drive head position sensing mechanism includes a guide rod, a guide
rod driver, and a guide rod sensor; said guide rod has a helical
groove and said guide rod driver includes a pin that fits in said
helical groove; and said guide rod sensor senses rotation of said
guide rod.
18. A syringe infusion pump as recited in claim 17, wherein said
guide rod and lead screw are mounted on a base.
19. A syringe infusion pump as recited in claim 17, wherein said
helical groove extends once around said guide rod.
20. A syringe infusion pump as recited in claim 17, wherein said
guide rod sensor includes an absolute encoder for detecting angular
movement of said guide rod.
21. A syringe infusion pump for use with a plurality of different
size syringes, each different size syringe having a different
syringe barrel diameter, and each of said plurality of syringes
including a plunger having a plunger axis received in the syringe
barrel along a barrel axis, said pump comprising: a drive head
configured to apply force to the plunger to operate the syringe,
said drive head including a force sensor positioned to sense force
applied to the plunger by the drive head, the force sensor having a
center; a syringe barrel holder comprising a barrel clamp including
a first clamp element and a second clamp element, said first and
second clamp elements being movable to engage and hold syringe
barrels of different diameters in a fixed position with the barrel
axis automatically aligned with said force sensor center
independent of the diameter of the barrel for each different
diameter syringe barrel; and a syringe plunger holder mounted on
said drive head comprising front and rear plunger clamps
cooperating to automatically position the plunger with the plunger
axis in alignment with the force sensor center, and with the
plunger axis in alignment with the barrel axis independent of the
diameter of the barrel of a syringe held in the barrel holder for
each different diameter syringe barrel.
22. A syringe infusion pump as recited in claim 21, wherein said
syringe barrel holder is configured to hold the barrel with the
barrel axis aligned with the force sensor center in response to the
syringe plunger holder positioning the plunger with the plunger
axis aligned with the force sensor center.
23. A syringe infusion pump for use with a plurality of different
size syringes, each different size syringe having a different
syringe barrel diameter, and each of said plurality of syringes
including a plunger with a plunger flange having a plunger axis
received in the barrel along a barrel axis, said pump comprising: a
drive head positioned and configured to push the plunger into the
syringe barrel for each different size syringe, said drive head
including a force sensor configured to sense force applied to the
plunger by the drive head, said force sensor having a center; a
syringe plunger holder configured and dimensioned to engage the
plunger of each different size syringe with the plunger axis
aligned with said force sensor center for each said different size
syringe; and a syringe barrel holder configured to hold each of the
syringe barrels of different diameters in a fixed position when the
drive head pushes the plunger into the syringe barrel.
24. A syringe infusion pump as recited in claim 23, wherein: said
syringe plunger holder is mounted on said drive head; and said
syringe plunger holder comprises a first plunger holder element and
a second plunger holder element, said first plunger holder element
being constrained to move a distance equal to a distance moved by
said second plunger holder element, but in an opposite
direction.
25. A syringe infusion pump as recited in claim 24, wherein said
first and second plunger holder elements engage the plunger with
the plunger flange positioned between said elements and the force
sensor, and with the plunger axis automatically centered on said
force sensor.
26. A syringe infusion pump as recited in claim 25, wherein said
syringe plunger holder comprises: a first plunger holder drive
member connected to said first plunger holder element; and a second
plunger holder drive member connected to said second plunger holder
element, said drive members providing said movement of said first
element and said second element.
27. A syringe infusion pump as recited in claim 26, wherein said
first and second plunger holder drive members comprise opposite
facing, spaced apart gear racks and said plunger holder further
comprises a plunger holder gear disposed therebetween and mating
therewith.
28. A syringe infusion pump as recited in claim 23, wherein: said
syringe barrel holder is configured and dimensioned to provide a
fixed position for the barrel axis with respect to said force
sensor center, said fixed position being independent of size of
said barrel for each different diameter syringe barrel; and said
syringe plunger holder engages each said plunger of each different
size syringe with said plunger automatically axis aligned with the
barrel axis of the syringe that said syringe barrel holder is
holding.
Description
RELATED APPLICATION DATA
[0001] This application is a continuation of U.S. Nonprovisional
Patent Application Ser. No. 12/157,477, filed Jun. 11, 2008,
entitled Syringe Infusion Pump, that claims the benefit of priority
of U.S. Provisional Patent Application Ser. No. 60/934,236, filed
Jun. 11, 2007, and titled Axially Centered Syringe Infusion Pump
Drive Mechanism, which is incorporated by reference herein in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention generally relates to the field of
infusion pumps. In particular, the present invention is directed to
a drive mechanism for a syringe infusion pump.
BACKGROUND
[0003] Infusion pumps currently present in the market consist of
two basic types, syringe infusion pumps and volumetric infusion
pumps. Typically, syringe infusion pumps accept a range of syringe
sizes, typically from 1 cc to 60 cc or more in volume from a
variety of syringe manufacturers. Typically these devices use a
motor under control of a microprocessor. A motor such as is
available from Maxon Precision Motors, Inc., Fall River, Mass., can
be used. The motor is connected to a lead screw which advances a
pushing element that pushes against the plunger of the syringe,
driving it into the barrel of the syringe, thus dispensing fluid or
other material. The devices have used sensors for determining the
size of syringe loaded, the position of the plunger within its
travel, whether the plunger is captured by the pushing element, and
the driving force needed to push the plunger. The devices have also
included encoders or other means for determining the motor
speed.
[0004] The syringe drives have fixed the barrel of the syringe
against a fixture, such as a V-block. A spring loaded clamp
mechanism has been used to capture the barrel of the syringe
against the V-block. Because the barrel diameter of a 1 cc syringe
is significantly smaller than the barrel diameter of a 60 cc
syringe, the pushing element has not always pushed along the center
line of the syringe, and the variance between pushing element and
syringe center line can be as much as 1 inch or more. The variance
in the syringe center line with respect to the pushing surface has
caused difficulties in measuring the force applied to the syringe
which is used to estimate fluid pressure within the syringe. The
variance has also caused inaccuracy in the resultant flow rate
because the syringe plunger has not been driven into the syringe
barrel squarely. Thus better schemes for mounting a syringe and
driving its plunger are needed to eliminate these problems, and
these schemes are provided by this patent application.
SUMMARY OF THE DISCLOSURE
[0005] In one implementation, the present disclosure is directed to
a syringe infusion pump for use with a plurality of different size
syringes, each different size syringe having a different syringe
barrel diameter, and each of the plurality of syringes including a
plunger having a plunger axis received in the barrel along a barrel
axis. The pump includes a drive head including a force sensor
positioned to sense force applied to the plunger by the drive head,
the force sensor having a center; and a syringe barrel holder
configured to hold each of the syringe barrels of different
diameters in a fixed position with the barrel axis aligned with the
force sensor center for each different diameter syringe barrel.
[0006] In another implementation, the present disclosure is
directed to a syringe infusion pump for use with a plurality of
different size syringes, each different size syringe having a
different syringe barrel diameter, and each of the plurality of
syringes including a plunger having a plunger axis received in the
syringe barrel along a barrel axis. The pump includes a drive head
configured to apply force to the plunger to operate the syringe,
the drive head including a force sensor positioned to sense force
applied to the plunger by the drive head, the force sensor having a
center; a syringe barrel holder comprising a barrel clamp including
a first clamp element and a second clamp element, the first and
second clamp elements being movable to engage and hold syringe
barrels of different diameters in a fixed position with the barrel
axis automatically aligned with the force sensor center independent
of the diameter of the barrel for each different diameter syringe
barrel; and a syringe plunger holder mounted on the drive head
comprising front and rear plunger clamps cooperating to
automatically position the plunger with the plunger axis in
alignment with the force sensor center, and with the plunger axis
in alignment with the barrel axis independent of the diameter of
the barrel of a syringe held in the barrel holder for each
different diameter syringe barrel.
[0007] In still another implementation, the present disclosure is
directed to a syringe infusion pump for use with a plurality of
different size syringes, each different size syringe having a
different syringe barrel diameter, and each of the plurality of
syringes including a plunger with a plunger flange having a plunger
axis received in the barrel along a barrel axis. The pump includes
a drive head positioned and configured to push the plunger into the
syringe barrel for each different size syringe, the drive head
including a force sensor configured to sense force applied to the
plunger by the drive head, the force sensor having a center; a
syringe plunger holder configured and dimensioned to engage the
plunger of each different size syringe with the plunger axis
aligned with the force sensor center for each the different size
syringe; and a syringe barrel holder configured to hold each of the
syringe barrels of different diameters in a fixed position when the
drive head pushes the plunger into the syringe barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For the purpose of illustrating the invention, the drawings
show aspects of one or more embodiments of the invention. However,
it should be understood that the present invention is not limited
to the precise arrangements and instrumentalities shown in the
drawings, wherein:
[0009] FIG. 1 is a three dimensional view of one embodiment of a
syringe infusion pump of the present patent application;
[0010] FIG. 2 is a three dimensional view of a drive head, motor,
and position sensing mechanism of the syringe infusion pump of FIG.
1;
[0011] FIGS. 3a-3c are three dimensional cutaway views of a portion
of the drive head of FIG. 2 showing a plunger in position in front
of a force sensor, and showing plunger clamp elements maintaining
the plunger axis in front of the center of the force sensor;
[0012] FIG. 4 is another three dimensional view of the drive head
of FIG. 2;
[0013] FIG. 5 is a block diagram of electronic components for the
syringe infusion pump;
[0014] FIGS. 6a-6d are three dimensional views of the barrel holder
portion of the syringe holder of FIG. 1 showing how the axis of the
barrel is maintained in the same position regardless of the
diameter of the barrel; and
[0015] FIG. 7 is another three dimensional view of the barrel
holder portion of the syringe holder of FIGS. 6a-6d.
DETAILED DESCRIPTION
[0016] One embodiment of the present patent application provides a
syringe infusion pump with a force sensor and a syringe holder. In
this embodiment the syringe holder includes a syringe plunger
holder and a syringe barrel holder. The syringe holder can include
mechanisms that provide the syringe plunger axis and the syringe
barrel axis automatically aligned with the force sensor for all
sized syringes.
[0017] Syringe infusion pump 20 includes drive head 22, syringe
barrel holder 24, motor 26, lead screw 28, and position sensing
device 30, as shown in FIGS. 1 and 2.
[0018] Motor 26 turns lead screw 28 clockwise or counterclockwise
to move drive head 22 toward or away from syringe barrel holder 24.
Drive head 22 includes force sensor 32 against which plunger 36 of
syringe 38 is positioned, as shown in FIGS. 3a-3c. Force sensor 32
can be one available from Strain Measurement Devices, Meriden,
Conn. Plunger 36 is held in position against force sensor 32 by
syringe plunger holder and syringe plunger flange holder 40 that
includes front plunger clamp element 42a and rear plunger clamp
element 42b. Plunger clamp elements 42a, 42b have V-grooves 44a,
44b that both hold plunger 36 and capture plunger flange 46. Thus,
plunger axis 54 extends directly into center 56 of force sensor 32,
as shown in FIGS. 3a-3c and FIG. 4.
[0019] Plunger clamp elements 42a, 42b are connected to gear 48
through racks 50a, 50b so that plunger clamp elements 42a, 42b are
constrained to move equal distances in opposite directions to each
other, maintaining plunger flange 46 centered before force sensor
32 and maintaining plunger axis 54 of plunger 36 extending directly
into center 56 of force sensor 32, regardless of the diameter of
plunger 36. Gear 48, racks 50a, 50b are included in drive head
housing 58. One embodiment has a first plunger flange holder drive
member that includes rack 50a and a second plunger flange holder
drive member that includes rack 50b.
[0020] Post 60 holds spring 62 for providing pressure for restoring
plunger clamp elements 42a, 42b toward each other, as shown in FIG.
4.
[0021] Force sensor 32 senses the force being applied to plunger 36
by drive head 22. Force sensor 32 is connected to motor processor
64 on electronic circuit board 66. Motor 26, barrel sensor 76, and
position sensor 78 are also connected to motor processor 64 on
electronic circuit board 66. Motor processor 64 can be one
available from Microchip Technology Inc., Chandler, Ariz. Barrel
sensor 76 and position sensor 78 can be ones available from US
Digital, Inc., Vancouver, Wash. Electronic circuit board 66 also
includes main microprocessor 68. Keypad 70, display 72, and battery
74 are connected to main microprocessor 68. Main processor 68 and
display 72 can be ones available from Sharp Electronics
Corporation, Romeoville, Ill.
[0022] Motor processor 64 controls speed of motor 26 in a software
closed control loop by monitoring two quadrature signals emitted by
a motor encoder that is part of motor 26. Motor processor 64
monitors output of force sensor 32 and provides an alarm signal to
alarm 79 if a preset force above a threshold is detected. This
force translates to a resultant fluid pressure based upon the cross
sectional area of syringe barrel 96. Motor processor 64 also
monitors barrel sensor 76 and determines its outer diameter and
thence its volume based upon a software look up table that cross
references barrel diameter to syringe barrel volume. Motor
processer 64 also monitors position sensor 78 and from this
position determines the state of fill of syringe barrel 96
installed.
[0023] Main processor 68 sends the display information to display
72 to be visually communicated to the user. Main processor 68 also
monitors keypad 70 to enable the user to control the device via key
press.
[0024] Battery 74 supplies power to all the electronics and motor
26.
[0025] Position of drive head 22 along lead screw 28 is measured
with position sensing device 30, as shown in FIGS. 1 and 2.
Position sensing device 30 includes guide rod 80 and position
sensor 78. Guide rod 80 has helical groove 84. Pin 86 extends from
drive head 22 into helical groove 84 and causes guide rod 80 to
rotate as drive head 22 moves under control of lead screw 28 and
motor 26. Because helical groove 84 extends only once around guide
rod 80, rotation of guide rod 80 can be used to accurately
determine position of drive head 22 along lead screw 28. Rotation
of guide rod 80 is measured with position sensor 78, and data from
position sensor 78 is fed to motor processor 64 on circuit board
66. In one embodiment, position sensor 78 includes an absolute
encoder for detecting angular movement of guide rod 80.
[0026] Syringe barrel holder 24 includes front barrel clamp element
90a and rear barrel clamp element 90b, as shown in FIGS. 6a-6d.
Front barrel clamp element 90a has a curved portion 94 to hold
syringe barrel 96 in position within groove 98 in rear barrel clamp
element 90b. Groove 98 of rear barrel clamp element 90b may have
different flat regions 100a, 100b to facilitate accommodating
barrels having different diameters. Flat regions 100c can be used
to facilitate accommodating barrels having collars.
[0027] Syringe barrel holder 24 also includes barrel flange clamp
102 on the side facing drive head 22, as shown in FIGS. 6a-6d and
7. Barrel flange clamp 102 is for capturing barrel flange 104 in a
fixed position, as shown in FIGS. 6a-6d and FIG. 7 so that position
of drive head 22 alone determines the amount of penetration of
plunger into syringe barrel 96. Syringe holder 106 includes syringe
plunger holder and syringe plunger flange holder 40 and syringe
barrel holder 24.
[0028] Syringe barrel holder 24 also includes barrel centering
mechanism 108 for automatically centering barrel axis 110 of barrel
96 along plunger axis 54 and along center 56 of force sensor 32.
Barrel centering mechanism 108 provides that both front barrel
clamp element 90a and rear barrel clamp element 90b move equal
distances in opposite directions when syringe barrel 96 is
inserted, maintaining barrel axis 110 in fixed position regardless
of the size of barrel 96, as shown in FIGS. 6a-6d.
[0029] Barrel centering mechanism 108 includes barrel racks 112a,
112b, as shown in FIGS. 6a-6d. Barrel rack 112a is connected to
front barrel clamp element 90a and to barrel clamp sensor gear 114
located in base 116, as shown in FIG. 1. Barrel rack 112b is
connected to rear barrel clamp element 90b and to barrel clamp
sensor gear 114. Barrel sensor 76 is also connected to barrel clamp
sensor gear 114, and from the magnitude of rotation it measures of
barrel clamp sensor gear 114 barrel sensor 76 determines the size
of syringe barrel 96. In one embodiment, barrel sensor 76 includes
an absolute encoder for detecting angular movement of barrel clamp
sensor gear 114. In another embodiment, barrel sensor 76 includes
an absolute encoder whose angular movement provides a measure of
the movement of barrel rack 112a, as shown in FIGS. 6b-6d. One
embodiment has a first barrel holder drive member that includes
barrel rack 112a and a second barrel holder drive member that
includes barrel rack 112b.
[0030] Spring shaft 124 carries spring 126 that provides a force
against base 116 pulling front barrel clamp element 90a toward rear
barrel clamp element 90b to apply pressure to and hold syringe
barrel 96. Guide shaft 128 extends from front barrel clamp element
90a through rear barrel clamp element 90b and into base 116.
[0031] While the disclosed methods and systems have been shown and
described in connection with illustrated embodiments, various
changes may be made therein without departing from the spirit and
scope of the invention as defined in the appended claims.
[0032] Exemplary embodiments have been disclosed above and
illustrated in the accompanying drawings. It will be understood by
those skilled in the art that various changes, omissions and
additions may be made to that which is specifically disclosed
herein without departing from the spirit and scope of the present
invention.
* * * * *