U.S. patent application number 12/689250 was filed with the patent office on 2011-07-21 for cartridge interface assembly with driving plunger.
Invention is credited to Oz Cabiri.
Application Number | 20110178463 12/689250 |
Document ID | / |
Family ID | 43903924 |
Filed Date | 2011-07-21 |
United States Patent
Application |
20110178463 |
Kind Code |
A1 |
Cabiri; Oz |
July 21, 2011 |
CARTRIDGE INTERFACE ASSEMBLY WITH DRIVING PLUNGER
Abstract
A cartridge interface assembly including a driving plunger
including an outer shaft, and a driver including an inner shaft,
the inner shaft mating with an intermediate shaft, the intermediate
shaft mating with the outer shaft, so that the shafts are movable
telescopically with respect to one another, wherein rotation of the
driver causes the driving plunger to advance in a direction away
from the driver.
Inventors: |
Cabiri; Oz; (Macabim,
IL) |
Family ID: |
43903924 |
Appl. No.: |
12/689250 |
Filed: |
January 19, 2010 |
Current U.S.
Class: |
604/154 |
Current CPC
Class: |
A61M 5/1456 20130101;
A61M 5/1452 20130101; A61M 5/2425 20130101; A61M 2005/14506
20130101; A61M 5/14566 20130101 |
Class at
Publication: |
604/154 |
International
Class: |
A61M 31/00 20060101
A61M031/00 |
Claims
1. A combination cartridge and cartridge interface assembly
comprising: a rotationally immobile cartridge having an inner
cylindrical surface, a first stopper slidingly inserted in the
cartridge, a distal end and a substance therein for administration
to a subject; a driving plunger comprising an outer shaft; and a
driver comprising an inner shaft, said inner shaft mating with said
outer shaft, so that said shafts are movable telescopically with
respect to one another, wherein rotation of said driver causes said
driving plunger to linearly advance in a direction away from said
driver, the arrangement being such that on insertion of the
cartridge interface assembly in the rotationally immobile
cartridge, the driving plunger is in complementary sealing
anti-rotation friction relation with the inner cylindrical surface
such that rotation of said driver causes said driving plunger to
linearly advance only towards the distal end until the driving
plunger abuts against the stopper whereupon the driving lunger
urges the stopper towards the distal end for metering substance
from the cartridge.
7. A method for interfacing between a driver and plunger slidingly
disposed in a rotationally immobile cartridge, the method
comprising: providing a a rotationally immobile cartridge having an
inner cylindrical surface, a first stopper slidingly inserted in
the cartridge, a distal end and a substance therein for
administration to a subject inserting a cartridge interface
assembly in the rotationally immobile cartridge, said cartridge
interface assembly comprising a driving plunger comprising an outer
shaft, and a driver comprising an inner shaft, said inner shaft
mating with said outer shaft, so that said shafts are moveable
telescopically with respect to one another; and rotating said
driver to cause said driving plunger to linearly advance distally
in said cartridge until abutting said plunger, the arrangement
being such that on insertion of the cartridge interface assembly in
the rotationally immobile cartridge, the driving plunger is in
complementary sealing anti-rotation friction relation with the
inner cylindrical surface such that rotation of said driver causes
said driving plunger to linearly advance only towards the distal
end until the driving plunger abuts against the stopper whereupon
the driving plunger urges the stopper towards the distal end for
metering substance from the cartridge.
8. The combination as recited in claim 1, wherein said
complementary sealing anti-rotation friction relation is the only
force impeding rotation of the driving plunger with respect to the
cartridge.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to external drug
pumps, and particularly to an assembly for pushing a drug from a
cartridge, in which the assembly interfaces between an actuator,
e.g., a motor, and a pushing device, e.g., a plunger in the
cartridge.
BACKGROUND OF THE INVENTION
[0002] External drug pumps are typically used to deliver to
patients substances which contain large molecules which cannot be
digested when administered orally, such as insulin, biogenic drugs
or protein drugs among others. Typically, the pump is adhered to
the abdomen or chest of the patient and delivers the substance to
the patient via a cannula or needle that is inserted into the
patient's skin.
[0003] PCT Patent Application PCT/IL2008/001312 (published as WO
2009/044401) to Gross and Cabiri (as well as U.S. patent
applications Ser. Nos. 12/244,666 and 12/244,668, the disclosures
of which are incorporated herein by reference), describes an
external drug pump. In this pump, a vial is provided that contains
a substance to be administered to a subject. (The terms "drug" and
"substance" are used interchangeably throughout the specification
and claims, and encompass any material administered to a subject.
The term "cartridge" throughout the specification and claims
encompasses any container for a drug, such as but not limited to, a
cartridge, vial, syringe, bottle, ampoule and many more, and is not
limited to any size or shape.)
[0004] The cartridge is sealed by a stopper, and has first and
second threaded elements (e.g., a screw and a nut) that are
threadedly coupled to each other. The distal end of the second
threaded element defines a coupling portion that couples the second
threaded element to the stopper. The first threaded element is
rotatable with respect to the cartridge, and is linearly immobile
with respect to the cartridge during rotation of the first threaded
element. The first threaded element, rotated by a motor, is
configured to linearly advance the stopper and at least the distal
end of the second threaded element toward the distal end of the
cartridge, without substantially rotating the second threaded
element and the stopper.
[0005] The following is provided to facilitate understanding of the
above described assembly.
[0006] Reference is made to FIG. 1, which illustrates the relevant
elements of the prior art cartridge assembly of WO 2009/044401
(based on FIG. 4 of that application), wherein a cartridge 22 is
inserted into a housing base.
[0007] The distal end of cartridge 22 is inserted into a cartridge
piercing mechanism 44, which pierces a seal at the distal end of
cartridge 22 having a stopper 24 therein (the stopper being an
example of a plunger, piston or pushing device; the stopper will
also be referred to as a plunger). Cartridge 22 is then lowered
into the housing base. Typically, opposing resilient arms 70
support the cartridge upon the housing base. As cartridge 22 is
lowered into the housing base, a first cog 52 engages a second cog
54. (First cog 52 is rotated by the motor, not shown here.) In some
applications, before insertion of cartridge 22 into the housing,
first threaded element 26 protrudes a distance h from the proximal
end of the cartridge. The proximal end of the first threaded
element (or of second cog 54) comprises a rounded portion 74.
Portion 34 of the housing base comprises an angled face 76. As
rounded portion 74 slides past the angled face, the first threaded
element is pushed the distance h inside the cartridge. As a result,
the first and second threaded elements 26 and 28 and the stopper 24
are displaced towards the distal end of the cartridge 22. During
operation, the motor (not shown) turns cog 52, which turns cog 54.
This linearly advances stopper 24 towards the distal end of the
cartridge 22, thereby administering the substance from cartridge
22.
[0008] Reference is now made to FIG. 2, which illustrates cartridge
22 with plunger 24 in an initial position before cartridge 22 has
been filled. The cartridge is either pre-filled by the manufacturer
or filled by the user, such as with a hypodermic needle 15 inserted
through a septum 17 in cartridge 22 (FIG. 3) or through a septum 19
in the housing of the drug pump (FIG. 4). As shown in FIG. 3, the
plunger 24 moves linearly in the cartridge 22 as the cartridge is
filled. Because no two cartridges will be filled with exactly the
same amount of substance, such as due to tolerances, different
injected volumes, different diameters or other dimensions,
different plunger shapes, air bubbles or other factors, there is
unfortunately no definitive position of the plunger 24 after
cartridge 22 has been filled. This can cause a problem because it
is possible that the overall length of the geared and threaded
mechanism (which is predefined) that interfaces with plunger 24 may
not meet the filled position of plunger 24 (which is unknown),
thereby causing a problem to properly push against plunger 24 in
order to administer the substance.
SUMMARY OF THE INVENTION
[0009] The present invention seeks to provide an improved assembly
for pushing a drug from a cartridge, in which the assembly
interfaces between an actuator, e.g., a motor, and a pushing
device, e.g., a plunger in the cartridge, as is described more in
detail hereinbelow. The invention solves the above mentioned
problem of the prior art. Although the invention is described with
reference to PCT Patent Application WO 2009/044401, nevertheless it
is understood that the invention is applicable for many types of
motor-driven drug cartridges.
[0010] There is thus provided in accordance with an embodiment of
the present invention a cartridge interface assembly including a
driving plunger including an outer shaft, and a driver including an
inner shaft, the inner shaft mating with an intermediate shaft, the
intermediate shaft mating with the outer shaft, so that the shafts
are movable telescopically with respect to one another, wherein
rotation of the driver causes the driving plunger to advance in a
direction away from the driver. The driver may include a gear
wheel.
[0011] In accordance with a non-limiting embodiment of the present
invention the inner shaft is threadedly received inside a hollow
portion of the intermediate shaft, and the intermediate shaft is
threadedly received inside a hollow portion of the outer shaft.
[0012] In accordance with an embodiment of the present invention
the cartridge interface assembly is inserted in a cartridge in
which a plunger is slidingly disposed, and rotation of the driver
causes the driving plunger to advance distally in the cartridge
until abutting the plunger.
[0013] There is also provided in accordance with an embodiment of
the present invention a method for interfacing between a driver and
a plunger slidingly disposed in a cartridge, the method including
inserting a cartridge interface assembly in the cartridge, the
cartridge interface assembly including a driving plunger including
an outer shaft, and a driver including an inner shaft, the inner
shaft mating with an intermediate shaft, the intermediate shaft
mating with the outer shaft, so that the shafts are movable
telescopically with respect to one another, and rotating the driver
to cause the driving plunger to advance distally in the cartridge
until abutting the plunger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will be understood and appreciated
more fully from the following detailed description taken in
conjunction with the drawings in which:
[0015] FIG. 1 is a simplified illustration of a prior art cartridge
assembly;
[0016] FIG. 2 is a simplified illustration of the prior art
cartridge with plunger in an initial position before the cartridge
has been filled;
[0017] FIG. 3 is a simplified illustration of filling the prior art
cartridge with a hypodermic needle inserted through a septum in the
cartridge;
[0018] FIG. 4 is a simplified illustration of filling the prior art
cartridge with a hypodermic needle inserted through a septum in a
housing of a drug pump;
[0019] FIGS. 5 and 6 are simplified pictorial and sectional
illustrations, respectively, of a cartridge interface assembly
including a driving plunger, constructed and operative in
accordance with an embodiment of the present invention; and
[0020] FIGS. 7 and 8 are simplified illustrations of the cartridge
interface assembly inserted in a cartridge, respectively before and
after the driving plunger abuts against the plunger of the
cartridge, in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0021] Reference is now made to FIGS. 5 and 6, which illustrate a
cartridge interface assembly 80, constructed and operative in
accordance with a non-limiting embodiment of the present
invention.
[0022] Cartridge interface assembly 80 includes a driving plunger
82 at the distal end of an outer shaft 84. A driver 86, such as but
not limited to, a gear wheel, includes an inner shaft 88. Inner
shaft 88 is received inside a hollow portion of an intermediate
shaft 90 and threadedly mates therewith. Intermediate shaft 90 is
in turn received inside a hollow portion of outer shaft 84 and
threadedly mates therewith. The shafts 84, 88 and 90 are arranged
to move telescopically with respect to one another. Outer shaft 84
may further include a proximal O-ring 92. The driving plunger 82
and O-ring 92 are preferably made of an elastomer, such as natural
or synthetic rubber. The other parts may be made of plastic or
metal.
[0023] Reference is now made to FIG. 7, which illustrates the
cartridge interface assembly 80 inserted in cartridge 22. Driving
plunger 82 is initially distanced somewhat from plunger 24 of
cartridge 22. Rotation of driver 86 (such as by meshing with a
rotating motor not shown) causes inner shaft 88 to rotate, which
causes intermediate shaft 90 to rotate and advance linearly towards
the distal end of cartridge interface assembly 80, that is, in the
direction towards driving plunger 82 as indicated by arrow 91. The
distal movement of intermediate shaft 90 in turn causes outer shaft
84 to advance distally together with driving plunger 82. The
friction of driving plunger 82 against the inner wall of cartridge
22 is such that it is much easier for driving plunger 82 to move
linearly than to rotate, such that the rotation of inner shaft 88
and intermediate shaft 90 cause driving plunger 82 to advance
distally in cartridge 22 until driving plunger 82 abuts against
plunger 24 as shown in FIG. 8.
[0024] Thus, with the present invention, no matter what the final
position of plunger 24 is after filling cartridge 22 with the
substance to be administered, the driving mechanism for pushing
plunger 24 will always properly contact plunger 24 via cartridge
interface assembly 80 due to the distance compensating action of
cartridge interface assembly 80.
[0025] It will be appreciated by persons skilled in the art that
the present invention is not limited by what has been particularly
shown and described hereinabove. Rather the scope of the present
invention includes both combinations and subcombinations of the
features described hereinabove as well as modifications and
variations thereof which would occur to a person of skill in the
art upon reading the foregoing description and which are not in the
prior art.
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