U.S. patent application number 17/674093 was filed with the patent office on 2022-09-15 for drive mechanisms for positive displacement pumps.
The applicant listed for this patent is Insulet Corporation. Invention is credited to Steven CARDINALI, Soroush KAMRAVA, Ian QUINN.
Application Number | 20220288304 17/674093 |
Document ID | / |
Family ID | 1000006208696 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220288304 |
Kind Code |
A1 |
KAMRAVA; Soroush ; et
al. |
September 15, 2022 |
DRIVE MECHANISMS FOR POSITIVE DISPLACEMENT PUMPS
Abstract
A novel embodiment of a pump system, for example, of the type
that would be used in a wearable drug delivery system, comprises,
in a preferred embodiment, a reservoir, a plunger, disposed within
the reservoir and driven by a scissor mechanism connected to a
drive mechanism through a linkage, such that a force imparted by
the drive mechanism in causes the scissor mechanism to expand
thereby causing the plunger move within the reservoir to force a
liquid drug contained within the reservoir through a fluid port to
a patient.
Inventors: |
KAMRAVA; Soroush; (Everett,
MA) ; CARDINALI; Steven; (Tewksbury, MA) ;
QUINN; Ian; (Concord, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Insulet Corporation |
Acton |
MA |
US |
|
|
Family ID: |
1000006208696 |
Appl. No.: |
17/674093 |
Filed: |
February 17, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
63160240 |
Mar 12, 2021 |
|
|
|
63306765 |
Feb 4, 2022 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2205/3592 20130101;
A61M 2005/14252 20130101; A61M 2005/1426 20130101; A61M 5/14248
20130101; A61M 2205/0266 20130101 |
International
Class: |
A61M 5/142 20060101
A61M005/142 |
Claims
1. A pump mechanism comprising: a reservoir comprising a tube-like
structure having one open end and one closed end, the closed end
configured with a fluid path; a plunger, disposed in the reservoir,
the plunger configured move longitudinally within the reservoir;
and a scissor mechanism coupled to the plunger and extending out
through the open end of the reservoir.
2. The pump mechanism of claim 1, further comprising: a drive
mechanism coupled to the scissor mechanism for driving the scissor
mechanism between a contracted position and an expanded position;
wherein movement of the scissor mechanism from the contracted
position to the expanded position causes the plunger to move
longitudinally in the reservoir toward the closed end of the
reservoir.
3. The pump mechanism of claim 2 wherein the drive mechanism
comprises: a leadscrew; and a drive nut in threaded engagement with
the leadscrew such that rotational motion of the leadscrew
translates to a linear motion of the drive nut; wherein the drive
nut is coupled to the scissor mechanism.
4. The pump mechanism of claim 3 further comprising: a linkage
coupling the drive nut to the scissor mechanism.
5. The pump mechanism of claim 1 wherein: the scissor mechanism is
rotatably coupled to the plunger at one end; and the scissor
mechanism is rotatably coupled to a body of a device at an opposite
end.
6. The pump mechanism of claim 5 wherein the reservoir is coupled
to the body of the device such that the reservoir and the end of
the scissor mechanism coupled to the body of the device are unable
to move with respect to each other.
7. A pump mechanism comprising: a reservoir comprising a tube-like
structure having one open end and one closed end, the closed end
configured with a fluid path; a plunger, disposed in the reservoir,
the plunger configured move longitudinally within the reservoir; a
first scissor mechanism coupled to the plunger and extending out
through the open end of the reservoir; and a second scissor
mechanism coupled to the first scissor mechanism via a linkage.
8. The pump mechanism of claim 7, further comprising: a drive
mechanism coupled to the second scissor mechanism for driving the
scissor mechanism between a contracted position and an expanded
position; wherein movement of the second scissor mechanism from the
contracted position to the expanded position movement of the first
scissor mechanism from the contracted position to the expanded
position, thereby causing the plunger to move longitudinally in the
reservoir toward the closed end of the reservoir.
9. The pump mechanism of claim 8 wherein the drive mechanism
comprises: a leadscrew; and a drive nut in threaded engagement with
the leadscrew such that rotational motion of the leadscrew
translates to a linear motion of the drive nut; wherein the drive
nut is coupled to the second scissor mechanism.
10. The pump mechanism of claim 9 wherein the reservoir and the
linkage are coupled to a body of a device such that the reservoir
and the linkage are unable to move with respect to each other.
11. A pump mechanism comprising: a reservoir comprising a tube-like
structure having one open end and one closed end, the closed end
configured with a fluid path; a plunger, disposed in the reservoir,
the plunger configured move longitudinally within the reservoir; a
first magnet, coupled to the plunger; a second magnet, external to
the reservoir and able to move longitudinally along an outside
surface of the reservoir; and a drive mechanism coupled to the
second magnet for driving the second magnet along the outside
surface of the reservoir.
12. The pump mechanism of claim 11, wherein movement of the second
magnet longitudinally along the outside surface of the reservoir
causes the first magnet, and thus the plunger, to move
longitudinally through the interior of the reservoir based on a
magnetic engagement between the second magnet and the first
magnet.
13. The pump mechanism of claim 12 wherein the second magnet is in
the shape of a collar surrounding the outside surface of the
reservoir;
14. The pump mechanism of claim 13 wherein the outside surface of
the reservoir is configured with one or more guide ridges to keep
the second magnet in alignment as it moves along the outside
surface of the reservoir.
15. The pump mechanism of claim 11 wherein the drive mechanism
comprises: a leadscrew; wherein: an outside surface of the second
magnet is configured with threads; the second magnet and leadscrew
are in threaded engagement with each other; rotation of the
leadscrew in a first direction will cause movement of the second
magnet in a first longitudinal direction along the outside surface
of the reservoir; and rotation of the leadscrew in a second
direction will cause movement of the second magnet in a second
longitudinal direction along the outside surface of the
reservoir.
16. The pump mechanism of claim 11 wherein the reservoir and the
drive mechanism are rigidly attached to a body of a device such
that the reservoir and drive mechanism are unable to move with
respect to each other.
17. A pump mechanism comprising: a reservoir comprising a tube-like
structure having one open end and one closed end, the closed end
configured with a fluid path; a plunger, disposed in the reservoir,
the plunger configured move longitudinally within the reservoir; a
tether, extending through a sealed opening in the closed end of the
reservoir and coupled to the plunger; and a drive mechanism, for
pulling the tether through the sealed opening, thereby causing the
plunger to move toward the closed end of the reservoir.
18. The pump mechanism of claim 17 wherein the drive mechanism
comprises a take-up reel, coupled to the tether, such that rotation
of the take-up reel will cause the tether to be pulled through the
sealed opening of the reservoir.
19. The pump mechanism of claim 18 further comprising: one or more
pulleys to guide the tether from the take-up reel to the sealed
opening.
20. The pump mechanism of claim 17 wherein the reservoir and the
drive mechanism are rigidly connected to a body of the device such
that the reservoir and the drive mechanism are unable to move with
respect to each other.
21. The pump mechanism of claim 17 wherein the tether is coupled to
a surface of the plunger interior to the reservoir.
22. The pump mechanism of claim 17 wherein an end of the tether
opposite an end coupled to the drive mechanism is anchored and
further wherein the tether is coupled to the plunger via one or
more pulleys mounted on a surface of the plunger exterior to the
reservoir.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 63/160,240, filed Mar. 12, 2021, entitled
"IMPROVED DRIVE MECHANISMS FOR POSITIVE DISPLACEMENT PUMPS", and
U.S. Provisional Patent Application No. 63/306,765, filed Feb. 4,
2022, entitled "PUMPING MECHANISM WITH WIRE-PULLED PLUNGER". The
contents of these application are incorporated herein in their
entireties.
BACKGROUND
[0002] Many conventional drug delivery systems are well known,
including, for example, wearable drug delivery devices of the type
shown in FIG. 1. The drug delivery device 100 can be designed to
deliver any type of liquid drug to a user. As used herein, the term
"liquid drug" is meant to include, any liquid drug, medicine,
therapeutic agent, or infusate, including, for example, insulin,
GLP-1, Pramlintide, or co-formulations thereof.
[0003] The drug delivery device 100 can be a single-use device
(e.g., filled once and used once and then discarded) or can be a
multiple-use device (e.g., filled one or more times and used after
one or more fillings). In specific embodiments, the drug delivery
device 100 can be, for example, an OmniPod.RTM. drug delivery
device manufactured by Insulet Corporation of Acton, Mass. The drug
delivery device 100 can be a drug delivery device such as those
described in U.S. Pat. Nos. 7,303,549, 7,137,964, or U.S. Pat. No.
6,740,059, each of which is incorporated herein by reference in its
entirety.
[0004] FIG. 2 illustrates an exemplary drug delivery device 100 of
the type shown in FIG. 1 with the cover removed. Drug delivery
device 100 typically includes a pump system which includes a drug
container, often referred to as a reservoir 202, that stores the
liquid drug. The liquid drug stored in the reservoir 202 may be
delivered to the user by expelling the drug from reservoir 202
using a driven plunger 204, for example, a leadscrew driven
plunger.
[0005] An exemplary pump system 300 is shown in perspective view in
FIG. 3A and in cross-sectional view in FIG. 3B. Pump system 300 may
comprise a drive mechanism 302 capable of providing a rotational
motion which will cause a tube nut 306 to rotate. Tube nut 306 is
in threaded engagement with leadscrew 304 such that when tube nut
306 is rotated by drive mechanism 302, leadscrew 304 moves in a
longitudinal direction within reservoir 202. Because leadscrew 304
is coupled to plunger 204, longitudinal movement of leadscrew 304
will cause plunger 204 to move longitudinally within reservoir 202.
Note that FIGS. 3A and 3B show reservoir 202 in an empty state,
wherein plunger 204 is positioned against the distal end wall of
reservoir 202. FIG. 3C shows reservoir 202 in a full state, wherein
plunger 204 is positioned at the proximal end of reservoir 202.
Note that, when the reservoir 202 is in a full or partially-full
state, leadscrew 304 must occupy space 308, shown in FIG. 3B.
[0006] One limitation of this design is that the total footprint of
the reservoir 202 and drive mechanism 302 is greater than the
length of reservoir 202 by as much as 2 times. This is due to the
fact that the leadscrew 304 needs to reach all the way into
reservoir 202 when reservoir 202 is in the empty state (i.e. it
must be approximately equal to the length of reservoir 202 minus
space taken by plunger 204). When reservoir 202 is full, leadscrew
304 will necessarily extend behind reservoir 202 to occupy space
308 at a length up to the length of the reservoir.
[0007] In wearable, on-body devices, it is desirable to keep pump
mechanism 300, as well as the overall drug delivery device 100, as
small as possible to minimize the impact to the wearer. Therefore,
it would be desirable to replace the prior art pump system 300 with
a positive displacement pump system having a different method of
driving the plunger 204 within the reservoir that does not require
the large footprint of the prior art pump mechanism 300. This would
reduce the size footprint of pump mechanism 300, thereby improving
the size impact of the overall drug delivery system 100 while
maintaining the benefits of the pumping methodology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of the wearable drug delivery
system of the type with which the present invention may be
used.
[0009] FIG. 2 is a perspective view of the wearable drug delivery
system of FIG. 1 having the cover removed to reveal the arrangement
of internal parts.
[0010] FIG. 3A is a perspective view of a pump mechanism utilized
in the drug delivery system of FIG. 1, showing the positioning of
various parts of the pump mechanism when the reservoir is in an
empty state.
[0011] FIG. 3B is a cross-sectional view of the pump mechanism of
FIG. 3A showing the positioning of the leadscrew responsible for
moving the plunger within the reservoir.
[0012] FIG. 3C is a perspective view of the pump mechanism of FIG.
3A showing the positioning of various parts of the pump mechanism
when the reservoir is in a full state.
[0013] FIGS. 4A and 4B are side cutaway views and FIGS. 4C and 4D
are upright and inverted perspective cutaway views respectively of
a first, preferred embodiment of the invention in which a scissor
linkage is used to move the plunger through the reservoir.
[0014] FIGS. 5A and 5B are upright and inverted cutaway views
respectively of a variant of the embodiment of FIGS. 4A-4D.
[0015] FIGS. 6A and 6B are side cutaway views and FIGS. 6C and 6D
are upright and inverted perspective views respectively of a second
embodiment of the invention in which coupled dual scissor linkages
are used to move the plunger through the reservoir.
[0016] FIG. 7 is a view of another embodiment of the invention
showing a different configuration for the scissor linkage.
[0017] FIG. 8 is a side cross-sectional view of a third embodiment
of the invention in which a magnetic linkage is used to move the
plunger through the reservoir.
[0018] FIG. 9 is a cross-sectional view of a fourth embodiment of
the invention in which the plunger is moved through the reservoir
using a flexible tether linkage wound about a take-up reel by
pulling the plunger toward the distal end of the reservoir.
[0019] FIGS. 10(A-C) show a fifth embodiment of the invention in
which the plunger is moved through the reservoir using a flexible
tether linkage wound about a take-up reel by pushing the plunger
toward the distal end of the reservoir.
DETAILED DESCRIPTION
[0020] This disclosure presents various systems, components and
methods for moving a liquid, typically a liquid drug, such as
insulin or GLP-1, from a liquid reservoir in a wearable drug
delivery device to a patient interface, typically a needle or
cannula. Each of the systems, components and methods disclosed
herein provides one or more advantages over conventional, prior art
systems, components and methods.
[0021] In various embodiments of the invention, the reservoir and
pump are integrated into a single component (referred to herein as
the "pump mechanism") and the drive mechanism of the prior art pump
mechanism is replaced by a new drive mechanism which reduces the
overall size footprint of the pump mechanism.
[0022] All embodiments of the pump mechanisms described herein
comprise various components including a reservoir, a plunger
configured to translate longitudinally through the interior of the
reservoir, a drive mechanism and a linkage between the drive
mechanism and the plunger. In all described embodiments, the
reservoir may comprise a tube-like structure having a proximal,
open and a distal, closed-end, wherein the closed-end may be
configured with a fluid path such as to allow the liquid drug
disposed between the plunger and the closed end of the reservoir to
be forced through the fluid path to a patient interface. The
reservoir may, in preferred embodiments of the invention, be
composed of a polyethylene or an injection-molded plastic, but, in
other embodiments, may be composed of any material impermeable to
the liquid drug disposed therein. The plunger may be composed of
any material and may be configured with one or more O-rings along a
circumferential surface such as to create a seal between the
plunger and the reservoir when the plunger is disposed within the
reservoir. The cross-sectional area of the reservoir and plunger
may be of any convenient shape; however, in preferred embodiments,
the cross-sectional shape of both the reservoir and the plunger is
oval or circular.
[0023] A first, preferred embodiment of the invention is shown in
various views in FIGS. 4A-4D and illustrates a pump mechanism
provided as part of a drug delivery device for delivery of a liquid
drug to a user.
[0024] Reservoir 202 stores the liquid drug prior to delivery to
the user. In some embodiments, the drug delivery device may come
with a prefilled reservoir containing the liquid drug. In other
embodiments, the reservoir 202 may be filled or refillable by the
user. Reservoir 202 may be fitted with a plunger 204 which is
longitudinally translatable through the interior length of
reservoir 202. The liquid drug is stored in the area 208 of
reservoir 202 between plunger 204 and the distal end of reservoir
202. Longitudinal translation of plunger 204 toward the distal end
of reservoir 208 will force the liquid drug from area 208 via fluid
path 206 to a patient interface, typically a needle or cannula (not
shown). Fluid path 206 may be provided with a one-way valve that
prevents fluids from entering area 208 of reservoir 202 (not
shown). Fluid path 206 may be located at any point such as to be in
fluid communication with space 208 within reservoir 202; however,
in preferred embodiments, fluid path 206 is located as close to the
distal end of reservoir 202 as possible to avoid wasting any liquid
drug that would otherwise get trapped at the far distal end of the
reservoir. Preferably, reservoir 202 is rigidly attached to the
body of the drug delivery device.
[0025] The longitudinal translation of the plunger 204 within
reservoir 202, in the preferred embodiments, is accomplished via a
scissor mechanism 402. Scissor mechanism 402 is attached, at one
end, to plunger 204 and at the other end, to support structure 410.
Support structure 410 may be rigidly attached to the body of the
drug delivery device 100 or may be part of and integral with the
body of the drug delivery device 100. As such, references to "the
body of the drug delivery device" herein are also meant to refer to
embodiments in which support structure 410 is separate from and
attached to the body of the drug delivery device. As such,
reference number 410 may hereinafter refer to a support structure
attached to the body of the device or to the body of the device
directly.
[0026] Reservoir 202 should be rigidly coupled to the body 410 of
the device such as to prevent movement between reservoir 202 and
the body 410 of the device. Additionally, one end of scissor
mechanism 402 should be rigidly attached to the body 410 of the
device such as to prevent relative movement between the end of the
scissor mechanism 402 attached to the body 410 of the device and
the reservoir 202. As such, the expansion of scissor mechanism 402
will drive plunger 204 toward the distal end of reservoir 202,
thereby expelling a quantity of the liquid drug contained within
space 208 through fluid path 206.
[0027] The mechanical motion needed to expand or contract scissor
mechanism 402 is provided by a drive mechanism. In the preferred
embodiment, the drive mechanism may comprise leadscrew 406 and a
drive nut 408. In other embodiments, the drive mechanism may be any
mechanism capable of imparting a force to scissor mechanism 402
necessary to expand scissor mechanism 402 and to overcome any
resistance from the liquid drug located in area 208 of reservoir
202. In the case wherein the drive mechanism is as shown in FIGS.
4A-4D, drive nut 408 is in threaded engagement with leadscrew 406
such that rotational motion of leadscrew 406 translates to a linear
motion of drive nut 408. Leadscrew 406 may be rotationally driven
via any known means, including, for example, by a motor 414 coupled
directly or via gearing 416 to leadscrew 406.
[0028] Drive nut 408 may be coupled to scissor mechanism 402 via a
linkage 404 which is coupled to drive nut 408 and to scissor
mechanism 402 at connection point 412. In addition, linkage 404 may
have one or more attachments to the body 410 of the device.
[0029] As shown in FIGS. 4A-4D, in some embodiments of the
invention, linkage 404 may be a four-segment linkage driven by
drive nut 408 which translates the linear motion of drive nut 408
into a circular or elliptical motion at connection point 412. Other
linkage designs may also be used and are considered to be within
the scope of the invention.
[0030] As such, the linear motion of drive nut 408 imparts a
mechanical force through linkage 404 such as to cause the expansion
or contraction of scissor mechanism 402. Linear motion of the drive
nut 408 in one direction may cause the expansion of scissor
mechanism 402, while linear motion of the drive nut 408 in the
opposite direction may cause the contraction of scissor mechanism
402. In the arrangement shown in FIGS. 4A-4D, linear motion of
drive nut 408 toward the body 410 of the device will cause the
contraction of scissor mechanism 402, while linear motion of drive
nut 408 in the opposite direction, away from the body 410 of the
device, will cause expansion of scissor mechanism 402.
[0031] As can be seen in FIG. 4D, scissor mechanism 402 is attached
to plunger 204 at connection point 418. In preferred embodiments of
the invention, connection point 418 is rotationally attached to
plunger 204 to allow for movement of the upper segments of scissor
mechanism 402 as it expands or contracts. Additionally, as shown in
FIG. 4C, the opposite end of scissor mechanism 402 is rotationally
attached to the body 410 of the device at connection point 415.
[0032] Leadscrew 406, drive nut 408, scissor mechanism 402 and
linkage 404 may, in some preferred embodiments, be composed of an
injection-molded plastic or a metal, for example, stainless steel.
However, these components may also be composed of any materials
capable of withstanding the required forces to make the pump
mechanism operable.
[0033] FIGS. 5A-5B show a variation of the embodiment of FIGS.
4A-4D in which the connection point 412 between linkage 404 and
scissor mechanism 402 is disposed on the opposite side of scissor
mechanism 402 from connection point 412 of the embodiment of FIGS.
4A-4D. Note that, in the embodiment of FIGS. 4A-4D, the linkage 404
extends to the side of reservoir 202, thereby allowing the overall
mechanism to have a smaller height profile at the expense of having
a larger width profile. The variation of the embodiment shown in
FIGS. 5A-5B has the opposite effect, wherein the linkage 404
extends underneath (or above) reservoir 202, thereby increasing the
height profile but decreasing the width profile of the mechanism. A
cross-sectional shape of the reservoir 202 can be adapted so as to
accommodate linkage 404 as it moves below (or above) reservoir 202.
For example, a bottom (or top) of reservoir 202 can be planar to
accommodate motion of linkage 404, and the plunger 204 can be
similarly modified in cross-sectional shape to correspond to the
modified cross-sectional shape of the reservoir 202 (e.g., modified
from a circular or oval cross-section).
[0034] FIGS. 6A-6D show several views of a second embodiment of the
invention in which linkage 404 is replaced by a second scissor
mechanism 602 which is coupled, at one end, directly to drive nut
408. At the opposite end, second scissor mechanism 602 is coupled
to scissor mechanism 402 via linkage 604, best shown in FIG. 6D. In
this embodiment, reservoir 202 and linkage 604 should both be
rigidly attached to the body 410 of the device, such that reservoir
202 and linkage 604 are unable to move with respect to each other.
As such, movement of drive nut 408 in the direction of the body 410
of the device will cause scissor mechanism 402 to contract while
movement of drive nut 408 in a direction away from the body 410 of
the device will cause scissor mechanism 402 to expand, thereby
driving plunger 204 toward the distal end of reservoir 202. All
other aspects of the second embodiment shown in FIGS. 6A-6D are
identical to those shown in the preferred embodiment in FIGS.
4A-4D.
[0035] FIG. 7 shows an alternate linkage in which one upper segment
of scissor mechanism 702 is coupled to plunger 204 via a sliding
mechanism 704 and the other upper segment of the scissor mechanism
702 is rotationally coupled to plunger 204 at fixed point 705. The
lower segments of scissor mechanism 702 are coupled to the body 410
of the device via sliding mechanisms 708a, 708b such that movement
of scissor mechanism 702 in the direction shown by arrow "A" causes
plunger 204 to move in the direction shown by arrow "B". One
advantage to this arrangement is that the drive mechanism may be
oriented so as to provide the required force in a direction
parallel to the direction shown by arrow "A", as opposed to other
embodiments, wherein the drive mechanism imparts a force in a
direction parallel with the direction of arrow "B". For example, in
the case where the drive mechanism comprises a leadscrew and a
drive nut, the leadscrew (not shown) may be oriented perpendicular
to the longitudinal axis of reservoir 202.
[0036] FIG. 8 shows a third embodiment of the invention in which
plunger 204 is configured with a first magnet 804. Preferably,
first magnet 804 is molded into, or otherwise securely coupled to
an underside of, plunger 204. The pump mechanism further comprises
a second magnet 802 which is disposed along an outside surface of
reservoir 202, such that movement of the second magnet 802 in a
longitudinal direction along the outside surface of reservoir 202
will cause first magnet 804 to move in the same longitudinal
direction based on a magnetic engagement between second magnet 802
and first magnet 804. The movement of the first magnet 804 in the
longitudinal direction toward the distal end of reservoir 202 will
drive plunger 204 in the longitudinal direction toward the distal
end of reservoir 202. O-Ring 806 may be provided to seal the
interface between plunger 204 and the inside wall of reservoir
202.
[0037] In this embodiment, the second magnet 802 may be configured
as a collar surrounding the outside surface of reservoir 202.
Second magnet 802 may be guided as it moves longitudinally along
the outside surface of reservoir 202 by one or more guides (not
shown) which may be, for example, ridges or channels defined on the
outside surface of reservoir 202.
[0038] In this embodiment, the drive mechanism may comprise any
mechanism configured to cause second magnet 804 to move
longitudinally along the outer surface of reservoir 202. In
preferred embodiments, the drive mechanism comprises a leadscrew
406 and wherein second magnet 802 has outside threads which are in
threaded engagement with leadscrew 406. Second magnet 802 conforms
to and encircles the outside surface of reservoir 202 such that
second magnet 802 is able to slide in the longitudinal direction
along the outside surface of reservoir 202 when driven by the
rotation of leadscrew 406.
[0039] As with other embodiments herein, leadscrew 406 may be
rotationally driven via any known means, including, for example, a
motor (not shown) coupled directly or via gearing to leadscrew 406.
The advantage of the embodiment shown in FIG. 8 over the other
embodiments discussed which use a scissor mechanism, is that
overall length of the pump mechanism in this embodiment may be
shorter because the space required to store the scissor mechanism
when it is in a contracted position may not be necessary.
[0040] FIG. 9 shows a fourth embodiment of the invention. In this
embodiment, plunger 204 is coupled to tether 904 which extends
through a sealed opening 912 in the distal end of reservoir 202. In
this embodiment, the drive mechanism comprises a take-up reel 906
which rotates in a manner such as to wind tether 904 about take-up
reel 906, thereby drawing plunger 204 toward the distal end of
reservoir 202. Tether 904 may pass through one or more seals 908,
910 which prevent the liquid drug from leaking out of reservoir 202
through opening 912 and which may be composed of, for example,
silicone or rubber. In some embodiments, tether 904 may be a metal
or polymer wire or film connected to take-up reel 906. One
advantage of this embodiment is that take-up reel 906 may be
disposed at any location within the body or housing of the drug
delivery device and may use one or more pulleys to direct tether
904 through opening 912, thereby allowing flexibility with respect
to the use of space within the device 100. O-Ring 914 may be
provided to seal the interface between plunger 204 and the inside
wall of reservoir 202.
[0041] FIGS. 10(A-C) show a fifth embodiment of the invention
similar to the fourth embodiment shown in FIG. 9. In this
embodiment, shown in a cross-sectional view in FIG. 10A, plunger
204 is coupled to tether 1002 which extends through two sealed
openings 1004(a,b) in the distal end of reservoir 202. Similar to
the fourth embodiment, the drive mechanism comprises a take-up reel
1006 which rotates in a manner such as to wind tether 1002 about
take-up reel 1006, thereby "pushing" plunger 204 from behind toward
the distal end of reservoir 202. Tether 1002 may pass through two
or more seals (not shown) in openings 1004(a,b), which prevent the
liquid drug from leaking out of reservoir 202 through openings
1004(a,b) and which may be composed of, for example, silicone or
rubber. In some embodiments, tether 1002, shown in more detail in
FIG. 10B, may be a metal or polymer wire, film or tape connected to
take-up reel 1006. Tether 1002 may extend through cutouts 1010(a,b)
in plunger 204 and may be sealed by O-ring 1012 which extends
around the outer edge of plunger 204. Additional seals (not shown)
may be required in cutouts 1010(a,b) to prevent the liquid drug
from leaking through cutouts 1010(a,b). Tether 1002 may be anchored
at the end opposite the end connected to take-up reel 1006 at
anchor point 1014. In a variation of this embodiment, opening 1004b
may be eliminated by anchoring tether 1002 to the interior surface
of distal wall 1016 of reservoir 202.
[0042] In this embodiment, plunger 204 is pulled by exerting a
force on the back side of plunger 204, for example, on opposite
ends of plunger 204, at stationary pulleys 1008(a,b), as shown in
FIG. 10A. Similar to the fourth embodiment described above, an
advantage of this embodiment is that take-up reel 1006 may be
disposed at any location within the body or housing of the drug
delivery device and may use one or more pulleys to direct tether
1002 through opening 1004a, thereby allowing flexibility with
respect to the use of space within the device 100.
[0043] Tether 1002 may be provided with a means to alternately pass
and block light therethrough. In one embodiment, tether 1002 mat be
provided with holes 1018 at regularly spaced intervals, as shown in
FIG. 10B, wherein the holes 1018 allow light to pass through tether
1002 and the areas between the holes 1018 prevent light from
passing through tether 1002. In other embodiments, tether 1002 may
be a film have alternating light and dark areas, wherein the light
areas allow light to pass through tether 1002 and the dark areas
block light from passing through tether 1002. Note that the tether
1002 described with respect to the embodiment of FIGS. 10A-C may
also be used with the embodiment of FIG. 9.
[0044] The embodiment of FIGS. 10A-C, as well as the embodiment
shown in FIG. 9, may further include a light source 1022, for
example, an LED, and a light sensor 1024 or scanner component
connected to circuitry and a processor that is programmed to count
a number of light flashes. As tether 1002 alternately passes and
blocks light from passing therethrough as it is pulled toward
take-up reel 1006, the number of light flashes can be counted by
sensing the light flashes with sensor 1024, and, thereby, the
processor may determine how much of tether 1002 has passed by the
sensor 1024. In this manner, because the spacing between the holes
1018 in (or the light and dark areas of) tether 1002 is known, it
may be determined how far plunger 204 has traveled, and
accordingly, how much liquid drug has been dispensed.
[0045] Further, when reservoir 202 is being filled with a liquid
drug by a user, light source 1022 and sensor 1024 may be operative
to determine how much liquid drug has been inserted into reservoir
204. As the user injects the liquid drug through an inlet (not
shown), tether 1002 may unwind from take-up reel 1006. As the holes
1018 in the tether 1002 pass (to the left in FIG. 10A) between
light source 1022 and sensor 1024, sensor 1024 may count the number
of light flashes it senses as light from the light source 1022
passes through the regularly spaced holes 1018 in tether 1002.
Based on the count of the number of light flashes, the processor
may determine how much tether 1002 has been unwound from take-up
reel 1006, and in this manner, may determine how far plunger 204
has traveled while reservoir 202 is being filled, and accordingly,
how much liquid drug the user has inserted into reservoir 202. As
such, tether 1002 with regularly spaced holes 1018 may function as
a "fuel gauge" to determine not only how much liquid drug has been
dispensed, but also how much liquid drug has been inserted into the
reservoir 202 and, by extension, how much liquid drug remains in
reservoir 202. Such information may be communicated wirelessly
(e.g., via Bluetooth) to a remote device having a user interface,
such that the user may know each of these variables: how much
liquid drug has been inserted into reservoir 202; how much liquid
drug has been dispensed at any point in time; and how much liquid
drug remains in reservoir 202.
[0046] The following examples pertain to various embodiments of the
pump mechanism suitable for use in a wearable drug delivery
device:
[0047] Example 1 is a first embodiment of a pump mechanism
comprising a reservoir, a plunger disposed in the reservoir and a
scissor mechanism coupled to the plunger for moving the plunger
longitudinally through the interior of the reservoir.
[0048] Example 2 is an extension of Example 1, or any other example
disclosed herein, wherein the pump mechanism further comprises a
drive mechanism coupled to the scissor mechanism for expanding and
contracting the scissor mechanism.
[0049] Example 3 is an extension of Example 2, or any other example
disclosed herein, wherein the drive mechanism comprises a leadscrew
and a drive nut in threaded engagement with the leadscrew, the
drive nut being coupled to the scissor mechanism.
[0050] Example 4 is an extension of Example 3, or any other example
disclosed herein, wherein the drive nut is coupled to the scissor
mechanism via a linkage.
[0051] Example 5 is an extension of Example 4, or any other example
disclosed herein, when the scissor mechanism is connected at one
end to the plunger and at the other end to the body of the
device.
[0052] Example 6 is an extension of Example 5, or any other example
disclosed herein, wherein the reservoir and one end of the scissor
mechanism are coupled to the body such as to prevent relative
movement therebetween.
[0053] Example 7 is a second embodiment of a pump mechanism
comprising a reservoir, a plunger disposed in the reservoir, a
first scissor mechanism coupled to the plunger for moving the
plunger longitudinally through the interior of the reservoir and a
second scissor mechanism coupled to the first scissor mechanism via
a linkage.
[0054] Example 8 is an extension of Example 7, or any other example
disclosed herein, wherein the pump mechanism further comprises a
drive mechanism coupled to the second scissor mechanism.
[0055] Example 9 is an extension of Example 8, or any other example
disclosed herein, wherein the drive mechanism comprises a leadscrew
in threaded engagement with a drive nut and wherein the drive nut
is coupled to the second scissor mechanism.
[0056] Example 10 is an extension of Example 9, or any other
example disclosed herein, wherein the reservoir and the linkage are
coupled to the body of the device such as to prevent relative
movement therebetween.
[0057] Example 11 is a third embodiment of a pump mechanism
comprising a reservoir, a plunger disposed in the reservoir and
coupled to a first magnet, a second magnet disposed along the
outside surface of the reservoir, and a drive mechanism coupled to
the second magnet for driving the second magnet along the outside
surface of the reservoir.
[0058] Example 12 is an extension of Example 11, or any other
example disclosed herein, wherein the first and second magnets are
in magnetic engagement with each other such that movement of the
second magnet along the outside surface of the reservoir causes
longitudinal movement of first magnet and, thereby, the plunger, in
the interior of the reservoir.
[0059] Example 13 is an extension of Example 12, or any other
example disclosed herein, wherein the second magnet is in the shape
of a collar disposed around the outside circumference of the
reservoir.
[0060] Example 14 is an extension of Example 13, or any other
example disclosed herein, wherein outside surface of the reservoir
is configured with ridges to guide movement of the second magnet
along the outside surface of the reservoir.
[0061] Example 15 is extension of Example 11, or any other example
disclosed herein, wherein the outside surface of the second magnet
is configured with threads and further wherein the second magnet is
in threaded engagement with the leadscrew such that rotational
motion of the leadscrew is translated to linear motion of the
second magnet.
[0062] Example 16 is an extension of Example 11, or any other
example disclosed herein, wherein the reservoir and drive mechanism
are rigidly attached to the body of a device such as to prevent
relative movement therebetween.
[0063] Example 17 is a fourth embodiment of a pump mechanism
comprising a reservoir, a plunger disposed in the reservoir, a
tether coupled to the plunger and extending through a sealed
opening in the closed end of the reservoir, and a drive mechanism
for pulling the tether through the sealed opening.
[0064] Example 18 is an extension of Example 17, or any other
example disclosed herein, wherein the drive mechanism comprises a
take-up reel coupled to the tether such that rotation of the
take-up reel will cause a tether to be pulled through the sealed
opening of the reservoir.
[0065] Example 19 is an extension of Example 18, or any other
example disclosed herein, wherein the pump mechanism further
comprises one or more pulleys to guide the tether from the take-up
reel to the sealed opening in the reservoir.
[0066] Example 20 is an extension of Example 17, or any other
example disclosed herein, wherein the reservoir and the drive
mechanism are rigidly connected to the body of the device such as
to prevent relative movement therebetween.
[0067] Example 20 is an extension of Example 17, or any other
example disclosed herein, wherein the tether is coupled to an
interior surface of the plunger.
[0068] Example 21 is an extension of Example 17, or any other
example disclosed herein, wherein the tether is anchored at one end
and coupled to an exterior surface of the plunger via one or more
pulleys.
[0069] To those skilled in the art to which the invention relates,
many modifications and adaptations of the invention may be
realized. Implementations provided herein, including sizes, shapes,
ratings and specifications of various components or arrangements of
components, and descriptions of specific manufacturing processes,
should be considered exemplary only and are not meant to limit the
invention in any way. As one of skill in the art would realize,
many variations on implementations discussed herein which fall
within the scope of the invention are possible. Moreover, it is to
be understood that the features of the various embodiments
described herein were not mutually exclusive and can exist in
various combinations and permutations, even if such combinations or
permutations were not made express herein, without departing from
the spirit and scope of the invention. Accordingly, the method and
apparatus disclosed herein are not to be taken as limitations on
the invention but as an illustration thereof. The scope of the
invention is defined by the claims which follow.
* * * * *