U.S. patent application number 11/554248 was filed with the patent office on 2007-03-29 for dispenser components and methods for patient infusion device.
Invention is credited to John R. Bussiere, J. Christopher Flaherty, John T. Garibotto, William Gorman, Gaurav Rohatgi.
Application Number | 20070073229 11/554248 |
Document ID | / |
Family ID | 32029849 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070073229 |
Kind Code |
A1 |
Gorman; William ; et
al. |
March 29, 2007 |
Dispenser Components And Methods For Patient Infusion Device
Abstract
A device for delivering fluid to a patient including an exit
port assembly, a reservoir including a side wall extending towards
an outlet connected to the exit port assembly, a threaded lead
screw received at least partly in the reservoir and longitudinally
extending towards the outlet, and a plunger secured to the lead
screw and having an outer periphery linearly slideable along the
side wall of the reservoir. A tube is coaxially received on the
lead screw and includes a longitudinal slot, a pin extending
through the lead screw and the slot of the tube, and a gear is
secured to the tube for rotation therewith.
Inventors: |
Gorman; William; (South
Hamilton, MA) ; Garibotto; John T.; (Charlestown,
MA) ; Flaherty; J. Christopher; (Topsfield, MA)
; Bussiere; John R.; (Littleton, MA) ; Rohatgi;
Gaurav; (Franklin, MA) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
28 STATE STREET
BOSTON
MA
02109-1775
US
|
Family ID: |
32029849 |
Appl. No.: |
11/554248 |
Filed: |
October 30, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10261003 |
Sep 30, 2002 |
7144384 |
|
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11554248 |
Oct 30, 2006 |
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Current U.S.
Class: |
604/131 |
Current CPC
Class: |
A61M 5/1452 20130101;
A61M 5/14276 20130101; A61M 2205/3365 20130101; A61M 2205/0266
20130101; A61M 2005/14573 20130101; A61M 2205/3523 20130101; A61M
2005/14208 20130101 |
Class at
Publication: |
604/131 |
International
Class: |
A61M 37/00 20060101
A61M037/00 |
Claims
1-70. (canceled)
71. A device for delivering fluid to a patient, comprising: an exit
port assembly; a reservoir including a side wall extending towards
an outlet connected to the exit port assembly; a threaded lead
screw received at least partly in the reservoir and longitudinally
extending towards the outlet, the lead screw including one of a
longitudinal extending groove and a laterally extending pin; a
plunger secured to the lead screw and having an outer periphery
linearly slideable along the side wall of the reservoir; and a
housing containing the reservoir, the lead screw and the plunger
and including the other of the longitudinal extending groove and
the laterally extending pin, wherein the laterally extending pin is
slidingly received within the longitudinally extending groove to
allow longitudinal advancement of the lead screw and prevent
rotation of the lead screw.
72. A device according to claim 71, wherein the lead screw includes
the longitudinally extending groove and the housing includes the
laterally extending pin.
73. A device according to claim 72, wherein the lead screw includes
two of the longitudinally extending grooves and the housing
includes two of the laterally extending pins, with one pin received
in each groove.
74. A device according to claim 71, wherein the lead screw includes
the laterally extending pin and the housing includes the
longitudinally extending groove.
75. A device according to claim 74, wherein the longitudinally
extending groove is unitarily formed as part of a portion of the
housing.
76. A device according to claim 74, wherein the lead screw includes
two of the laterally extending pins and the housing includes two of
the longitudinally extending grooves, with one pin received in each
groove.
77. A device according to claim 76, wherein the longitudinally
extending grooves are unitarily formed as part of portions of the
housing.
78. A device according to claim 71, wherein the reservoir contains
a therapeutic fluid.
79. A device according to claim 78, wherein the therapeutic fluid
is insulin.
80. A device according to claim 71, wherein the exit port assembly
includes a transcutaneous patient access tool.
81. A device according to claim 80, wherein the transcutaneous
patient access tool comprises a needle.
82-111. (canceled)
112. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir; and a non-rotating nut
assembly receiving the lead screw and including, at least two
laterally movable threaded inserts having threaded surfaces for
threadedly receiving the lead screw upon being biased laterally
inwardly against the lead screw, a spring biasing the threaded
inserts laterally inwardly against the lead screw; and at least one
spacer cam movable between a first position preventing the threaded
inserts from being biased laterally inwardly against the lead screw
and a second position allowing the threaded inserts to be biased
laterally inwardly against the lead screw.
113. A device according to claim 112, wherein, in the first
position, the spacer cam is positioned between the threaded
inserts.
114. A device according to claim 113, wherein the spacer cam is
laterally movable with respect to the lead screw.
115. A device according to claim 113, wherein the spacer cam is
longitudinally movable with respect to the lead screw.
116. A device according to claim 112, further comprising a gear
operatively secured to the lead screw such that rotation of the
gear causes rotation of the lead screw, and wherein the spacer cam
is operatively connected to the gear such that rotation of the gear
causes movement of the spacer cam to the second position.
117. A device according to claim 116, further comprising: a gear
cam connected to the gear; and a spacer follower connected to the
spacer cam and received against the gear cam, wherein the gear cam
and the spacer follower are shaped such that rotation of the gear
cam with the gear causes movement of the spacer follower and
movement of the spacer cam to the second position.
118. A device according to claim 117, wherein the spacer follower
and the spacer cam are connected through a spacer ring coaxially
positioned about the lead screw.
119. A device according to claim 118, wherein the gear cam is
provided as part of a gear ring coaxially positioned about the lead
screw and including at least one spline extending into a keyway of
the gear.
120. A device according to claim 119, wherein the gear cam is
formed in a radially outwardly facing surface of the spline.
121. A device according to claim 120, wherein the gear ring
includes a latch allowing the spacer follower to exit the gear cam
and preventing the spacer follower from re-entering the gear
cam.
122. A device according to claim 112, wherein the reservoir
contains a therapeutic fluid.
123. A device according to claim 122, wherein the therapeutic fluid
is insulin.
124. A device according to claim 112, wherein the exit port
assembly includes a transcutaneous patient access tool.
125. A device according to claim 124, wherein the transcutaneous
patient access tool comprises a needle.
126. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet, the lead screw
comprised of electrically resistive material; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir; a non-rotating longitudinally
fixed nut made from electrically conductive material, the nut
threadedly receiving the lead screw such that rotation of the lead
screw causes linear movement of the lead screw with respect to the
nut; and a processor connected to the nut and the lead screw and
programmed to detect an electrical signal between the nut and the
lead screw.
127. A device according to claim 126, wherein the processor is
further programmed to determine a relative position between the nut
and the lead screw based on one of the electrical signal and
changes to the electrical signal.
128. A device according to claim 126, wherein the reservoir
contains a therapeutic fluid.
129. A device according to claim 128, wherein the therapeutic fluid
is insulin.
130. A device according to claim 126, wherein the exit port
assembly includes a transcutaneous patient access tool.
131. A device according to claim 130, wherein the transcutaneous
patient access tool comprises a needle.
132. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir; a non-rotating longitudinally
fixed nut threadedly receiving the lead screw such that rotation of
the lead screw causes linear movement of the lead screw with
respect to the nut; and a rotary motor mated to a proximal end of
the lead screw for causing rotation of the lead screw relative to
the motor; and a longitudinal guide extending parallel with the
lead screw and receiving the motor, wherein the guide allows
longitudinal movement of the motor and prevents rotation of the
motor.
133. A device according to claim 132, wherein the rotary motor and
the longitudinal guide have non-circular cross-sections preventing
rotation of the motor with respect to the guide.
134. A device according to claim 132, further comprising: a
reflector secured to the motor; at least one light emitter fixed
with respect to the motor and directed longitudinally at the
reflector; and at least one light detector fixed with respect to
the motor and directed longitudinally at the reflector.
135. A device according to claim 134, wherein the reflector is
oriented at an angle with respect to the guide of the motor.
136. A device according to claim 134, further comprising a
processor connected to the light emitter and the light detector and
programmed to determine a longitudinal distance of the reflector
from the light emitter based upon a lateral distance between a beam
of light directed from the light emitter to the reflector and the
beam of light as received by the light detector from the
reflector.
137. A device according to claim 132, further comprising: at least
one light emitter directed laterally within the longitudinal guide;
and at least one light detector directed laterally within the
longitudinal guide; wherein one of the guide and the motor is
relatively light reflective.
138. A device according to claim 137, wherein the motor is
relatively reflective.
139. A device according to claim 137, comprising a plurality of the
light emitters and light detectors spaced longitudinally within the
guide.
140. A device according to claim 132, wherein the reservoir
contains a therapeutic fluid.
141. A device according to claim 140, wherein the therapeutic fluid
is insulin.
142. A device according to claim 132, wherein the exit port
assembly includes a transcutaneous patient access tool.
143. A device according to claim 142, wherein the transcutaneous
patient access tool comprises a needle.
144. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir; a non-rotating longitudinally
fixed nut threadedly receiving the lead screw such that rotation of
the lead screw causes linear movement of the lead screw with
respect to the nut; an encoder disk coaxially secured to the lead
screw for rotation therewith and including radially spaced light
reflective indicia thereon; a light emitter directed at the encoder
disk; and a light detector directed at the encoder disk.
145. A device according to claim 144, wherein the radially spaced
light reflective indicia are located on an outer circumferential
surface of the encoder disk.
146. A device according to claim 144, further comprising: a
relatively light reflective reference element secured to the lead
screw for longitudinal movement therewith; at least one light
emitter directed laterally at the lead screw; and at least one
light detector directed laterally at the lead screw.
147. A device according to claim 146,wherein the encoder disk
includes a recess on a face thereof to receive the reference
element.
148. A device according to claim 144, wherein the reservoir
contains a therapeutic fluid.
149. A device according to claim 148, wherein the therapeutic fluid
is insulin.
150. A device according to claim 144, wherein the exit port
assembly includes a transcutaneous patient access tool.
151. A device according to claim 150, wherein the transcutaneous
patient access tool comprises a needle.
152-158. (canceled)
159. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir; a gear radially extending
from the lead screw and made from electrically conductive material,
wherein the gear and the lead screw are operatively connected such
that rotation of the gear causes longitudinally movement of the
lead screw towards the outlet of the reservoir; a ratchet engaging
teeth of the gear such that movement of the ratchet in a first
direction causes rotation of the gear while movement of the ratchet
in a second direction causes no rotation of the gear, wherein the
ratchet is made from electrically conductive material; a first
electrical lead connected to the gear; and a second electrical lead
connected to the ratchet.
160. A device according to claim 159, further comprising a
processor connected to the first and second electrical leads and
programmed to determine whether the gear has rotated based at least
in part on electrical discontinuities between the ratchet and the
gear.
161. A device according to claim 159, further comprising at least
one pawl allowing rotation of the gear in a single direction and a
third electrical lead connected to the pawl, and wherein the pawl
is made from electrically conductive material.
162. A device according to claim 161, further comprising a
processor connected to the first, the second and the third
electrical leads and programmed to determine whether the gear has
rotated based at least in part on electrical discontinuities
between the ratchet, the pawl and the gear.
163. A device according to claim 159, further comprising: an
elongated shape memory element having a changeable length
decreasing from an uncharged length to a charged length when at
least one charge is applied to the shape memory element, wherein
the shape memory element is secured to the ratchet such that the
changeable length of the shape memory element decreasing from an
uncharged length to a charged length causes movement of the ratchet
in one of the first and the second directions; and a processor
connected to the shape memory element and the first and second
electrical leads, and programmed to, apply a charge to the shape
memory element in order to cause rotation of the gear, determine
whether the gear has been rotated based at least in part on
electrical discontinuities between the ratchet and the gear, and
remove the charge from the shape memory element upon determining
that the gear has been rotated.
164. A device according to claim 159, wherein the reservoir
contains a therapeutic fluid.
165. A device according to claim 164, wherein the therapeutic fluid
is insulin.
166. A device according to claim 159, wherein the exit port
assembly includes a transcutaneous patient access tool.
167. A device according to claim 166, wherein the transcutaneous
patient access tool comprises a needle.
168. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a lead screw
received at least partly in the reservoir and longitudinally
extending towards the outlet; a plunger secured to the lead screw
and having an outer periphery linearly slideable along the side
wall of the reservoir, such that linear movement of the lead screw
towards the outlet of the reservoir forces fluid within the
reservoir through the outlet to the exit port assembly; a sensor
detecting linear movement of the lead screw; an elongated shape
memory element having a changeable length decreasing from an
uncharged length to a charged length when at least one charge is
applied to the shape memory element, wherein the shape memory
element is operatively connected to the lead screw such that the
changeable length of the shape memory element decreasing from an
uncharged length to a charged length causes linear movement of the
lead screw towards the outlet of the reservoir; and a processor
connected to the shape memory element and the sensor detecting
linear movement of the lead screw, and programmed to apply a charge
to the shape memory element and remove the charge upon receiving a
signal from the sensor indicative of linear movement of the lead
screw.
169. A device according to claim 168, wherein the reservoir
contains a therapeutic fluid.
170. A device according to claim 169, wherein the therapeutic fluid
is insulin.
171. A device according to claim 168, wherein the exit port
assembly includes a transcutaneous patient access tool.
172. A device according to claim 171, wherein the transcutaneous
patient access tool comprises a needle.
173. A device according to claim 168, wherein the sensor comprises:
a reflector secured to the lead screw; at least one light emitter
fixed with respect to the lead screw and directed longitudinally at
the reflector; and at least one light detector fixed with respect
to the lead screw and directed longitudinally at the reflector.
174. A device for delivering fluid to a patient, comprising: an
exit port assembly; a reservoir including a side wall extending
towards an outlet connected to the exit port assembly; a threaded
lead screw received at least partly in the reservoir and
longitudinally extending towards the outlet; a plunger secured to
the lead screw and having an outer periphery linearly slideable
along the side wall of the reservoir, such that linear movement of
the lead screw towards the outlet of the reservoir forces fluid
within the reservoir through the outlet to the exit port assembly;
a reflector secured to the lead screw; at least one light emitter
fixed with respect to the lead screw and directed longitudinally at
the reflector; and at least one light detector fixed with respect
to the lead screw and directed longitudinally at the reflector.
175. A device according to claim 174, wherein the reflector is
oriented at an angle with respect to the lead screw.
176. A device according to claim 174, further comprising a
processor connected to the light emitter and the light detector and
programmed to determine a longitudinal distance of the reflector
from the light emitter based upon a lateral distance between a beam
of light directed from the light emitter to the reflector and the
beam of light as received by the light detector from the
reflector.
177. A device according to claim 174, wherein the reservoir
contains a therapeutic fluid.
178. A device according to claim 177, wherein the therapeutic fluid
is insulin.
179. A device according to claim 174, wherein the exit port
assembly includes a transcutaneous patient access tool.
180. A device according to claim 179, wherein the transcutaneous
patient access tool comprises a needle.
181. A device for delivering fluid to a patient, comprising: a
housing; a reservoir contained within the housing and including a
side wall extending towards an outlet; a threaded lead screw
received at least partly in the reservoir and longitudinally
extending towards the outlet; a plunger secured to the lead screw
and having an outer periphery linearly slideable along the side
wall of the reservoir; means for rotating the lead screw; means for
engaging the lead screw such that rotation of the lead screw in a
first direction causes the lead screw to advance longitudinally
towards the outlet; and means for sensing rotation of the lead
screw.
182. The device of claim 181, wherein the means for engaging the
lead screw comprises means for moving from a disengaged state to an
engaged state.
183. The device of claim 181, further comprising a fluid path
coupled to the outlet, said fluid path comprising a transcutaneous
patient access tool, wherein said fluid path and transcutaneous
access tool are contained within the housing when the
transcutaneous access tool is in a first position.
184. The device of claim 181 further comprising means for sensing
longitudinal displacement of the lead screw.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a division of co-pending U.S.
patent applicantion Ser. No. 10/261,003, which is related to U.S.
patent application Ser. No. 09/943,992, and is also related to
co-pending U.S. patent application Ser. No. 10/260,192 all of which
are assigned to the assignee of the present application, and are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to medical devices,
systems and methods, and more particularly to small, low cost,
portable infusion devices and methods that are useable to achieve
precise, sophisticated, and programmable flow patterns for the
delivery of therapeutic liquids such as insulin to a mammalian
patient. Even more particularly, the present invention is directed
to various new and improved dispenser components and methods for an
infusion device.
BACKGROUND OF THE INVENTION
[0003] Today, there are numerous diseases and other physical
ailments that are treated by various medicines including
pharmaceuticals, nutritional formulas, biologically derived or
active agents, hormonal and gene based material and other
substances in both solid or liquid form. In the delivery of these
medicines, it is often desirable to bypass the digestive system of
a mammalian patient to avoid degradation of the active ingredients
caused by the catalytic enzymes in the digestive tract and liver.
Delivery of a medicine other than by way of the intestines is known
as parenteral delivery. Parenteral delivery of various drugs in
liquid form is often desired to enhance the effect of the substance
being delivered, insuring that the unaltered medicine reaches its
intended site at a significant concentration. Also, undesired side
effects associated with other routes of delivery, such as systemic
toxicity, can potentially be avoided.
[0004] Often, a medicine may only be available in a liquid form, or
the liquid version may have desirable characteristics that cannot
be achieved with solid or pill form. Delivery of liquid medicines
may best be accomplished by infusing directly into the
cardiovascular system via veins or arteries, into the subcutaneous
tissue or directly into organs, tumors, cavities, bones or other
site specific locations within the body.
[0005] Parenteral delivery of liquid medicines into the body is
often accomplished by administering bolus injections using a needle
and reservoir, or continuously by gravity driven dispensers or
transdermal patch technologies. Bolus injections often imperfectly
match the clinical needs of the patient, and usually require larger
individual doses than are desired at the specific time they are
given. Continuous delivery of medicine through gravity feed systems
compromise the patient's mobility and lifestyle, and limit the
therapy to simplistic flow rates and profiles. Transdermal patches
have special requirements of the medicine being delivered,
particularly as it relates to the molecular structure, and similar
to gravity feed systems, the control of the drug administration is
severely limited.
[0006] Ambulatory infusion pumps have been developed for delivering
liquid medicaments to a patient. These infusion devices have the
ability to offer sophisticated fluid delivery profiles
accomplishing bolus requirements, continuous infusion and variable
flow rate delivery. These infusion capabilities usually result in
better efficacy of the drug and therapy and less toxicity to the
patient's system. An example of a use of an ambulatory infusion
pump is for the delivery of insulin for the treatment of diabetes
mellitus. These pumps can deliver insulin on a continuous basal
basis as well as a bolus basis as is disclosed in U.S. Pat. No.
4,498,843 to Schneider et al.
[0007] The ambulatory pumps often work with a reservoir to contain
the liquid medicine, such as a cartridge, a syringe or an IV bag,
and use electromechanical pumping or metering technology to deliver
the medication to the patient via tubing from the infusion device
to a needle that is inserted transcutaneously, or through the skin
of the patient. The devices allow control and programming via
electromechanical buttons or switches located on the housing of the
device, and accessed by the patient or clinician. The devices
include visual feedback via text or graphic screens, such as liquid
crystal displays known as LCD's, and may include alert or warning
lights and audio or vibration signals and alarms. The device can be
worn in a harness or pocket or strapped to the body of the
patient.
[0008] Currently available ambulatory infusion devices are
expensive, difficult to program and prepare for infusion, and tend
to be bulky, heavy and very fragile. Filling these devices can be
difficult and require the patient to carry both the intended
medication as well as filling accessories. The devices require
specialized care, maintenance, and cleaning to assure proper
functionality and safety for their intended long term use. Due to
the high cost of existing devices, healthcare providers limit the
patient populations approved to use the devices and therapies for
which the devices can be used.
[0009] Clearly, therefore, there was a need for a programmable and
adjustable infusion system that is precise and reliable and can
offer clinicians and patients a small, low cost, light-weight,
easy-to-use alternative for parenteral delivery of liquid
medicines.
[0010] In response, the applicant of the present application
provided a small, low cost, light-weight, easy-to-use device for
delivering liquid medicines to a patient. The device, which is
described in detail in co-pending U.S. application Ser. No.
09/943,992, filed on Aug. 31, 2001, includes an exit port, a
dispenser for causing fluid from a reservoir to flow to the exit
port, a local processor programmed to cause a flow of fluid to the
exit port based on flow instructions from a separate, remote
control device, and a wireless receiver connected to the local
processor for receiving the flow instructions. To reduce the size,
complexity and costs of the device, the device is provided with a
housing that is free of user input components, such as a keypad,
for providing flow instructions to the local processor. What is
still desired, however, are additional new and improved components
and methods for devices for delivering fluid to a patient.
SUMMARY OF THE INVENTION
[0011] The present invention provides a device for delivering fluid
to a patient. The device includes an exit port assembly, a
reservoir including a side wall extending towards an outlet
connected to the exit port assembly, a threaded lead screw received
at least partly in the reservoir and longitudinally extending
towards the outlet, and a plunger secured to the lead screw. The
plunger has an outer periphery longitudinally slideable along the
side wall of the reservoir so that longitudinal movement of the
lead screw causes fluid to be forced out of the outlet to the exit
port assembly. A tube is coaxially received on the lead screw and
includes a longitudinal slot, and a pin extends through the lead
screw and the slot of the tube such that the lead screw rotates
with the tube. A gear having radially extending teeth is secured to
the tube for rotation therewith.
[0012] According to one aspect of the present invention, the device
further includes a reference element secured to the pin, at least
one light emitter directed laterally at the tube for directing a
beam of light at the tube, and at least one light detector directed
laterally at the tube for receiving the beam of light reflected
away from the tube. One of the tube and the reference element has a
light reflective outer surface, so that the detector provides a
signal upon movement of the reference element past the detector. In
this manner, longitudinal movement of the lead screw is monitored.
According to one aspect, the reference element has a light
reflective outer surface. According to another aspect, the
reference element is annular and coaxially received for sliding
movement along an outer surface of the tube.
[0013] According to a further aspect of the present invention, a
processor is connected to the light detector and is programmed to
apply a charge to the shape memory element and remove the charge
upon receiving a signal from the light detector indicative of a
desired amount of linear movement of the lead screw. In this
manner, power is applied to the shape memory element only for as
long as needed to cause movement of the lead screw as desired.
[0014] According to an additional aspect of the present invention,
the lead screw extends through and is threadedly received within a
nut assembly that is non-rotating with respect to the lead screw,
and is linearly fixed in position with respect to the reservoir.
Upon rotation of the lead screw, therefore, the lead screw moves
longitudinally through and with respect to the nut assembly.
According to a further aspect, the nut assembly includes at least
two laterally movable threaded inserts including threaded surfaces
for threadedly receiving the lead screw upon being biased laterally
inwardly against the lead screw, a spring biasing the threaded
inserts laterally inwardly against the lead screw, and at least one
spacer cam movable between a first position preventing the threaded
inserts from being biased laterally inwardly against the lead screw
and a second position allowing the threaded inserts to be biased
laterally inwardly against the lead screw.
[0015] According to another aspect of the present invention, the
fluid delivery device also includes a set of at least two pawls,
wherein each pawl engages teeth of the gear and allows rotation of
the gear in a single direction. The pawls allow rotation of the
gear, and the tube and the lead screw, in a single direction. Among
other features and benefits, the deployment of at least two pawls
provides redundancy in case one of the pawls snaps or otherwise
fails during operation of the device.
[0016] According to yet another aspect of the present invention,
the device includes a ratchet member movable with respect to the
gear and including a ratchet engaging teeth of the gear such that
movement of the ratchet in a first direction causes rotation of the
gear while movement of the ratchet in a second direction causes no
rotation of the gear. An elongated shape memory element is secured
to the ratchet member. The shape memory element has a changeable
length decreasing from an uncharged length to a charged length when
at least one charge is applied to the shape memory element and is
arranged with the ratchet member such that the changeable length of
the shape memory element decreasing from an uncharged length to a
charged length causes movement of the ratchet in one of the first
and the second directions.
[0017] According to one aspect, the shape memory element is
arranged such that the changeable length of the shape memory
element decreasing from an uncharged length to a charged length
causes movement of the ratchet in the first direction. According to
a further aspect, the ratchet member includes at least one anchor
fixed in position with respect to the gear, and at least one spring
biasing the ratchet in the second direction and away from the
anchor. The springs comprise bent portions of flat sheet material.
The ratchet is connected to the springs through a flat extension
portion, which also is biased away from the anchors by the
springs.
[0018] According to yet a further aspect of the present invention,
a first electrical lead is connected to the gear, a second
electrical lead is connected to the ratchet, and a third electrical
lead is connected to the pawl. In addition, the gear, the ratchet,
and the pawls are made from electrically conductive material. A
processor is connected to the first, the second and the third
electrical leads and is programmed to determine whether the gear
has been rotated based at least in part on electrical
discontinuities between the ratchet, the gear, and the pawl.
According to another aspect, the processor is programmed to apply a
charge to the shape memory element and remove the charge upon
sensing a predetermined number of electrical discontinuities among
the electrical leads. In this manner, power is applied to the shape
memory element only for as long as needed to cause movement of the
lead screw as desired.
[0019] According to another aspect of the present invention, an
electrically conductive brush is biased against a face of the gear,
and the face of the gear includes radially spaced bumps thereon.
One of the face and the bumps are electrically conductive, and the
brush is connected to a processor, which is programmed to determine
whether the gear has rotated based at least in part on electrical
discontinuities between the brush and the gear.
[0020] According to an additional aspect of the present invention,
an encoder disk is coaxially secured to the tube and includes
radially spaced light reflective indicia thereon. A light emitter
and a light detector are directed at the encoder disk and connected
to a processor, which is programmed to determine the amount of
rotation of the tube based upon movement of the radially spaced
light reflective indicia of the encoder disk.
[0021] According to one aspect of the present invention, the lead
screw extends through a fixed, non-rotatable nut, a rotary motor is
mated to a proximal end of the lead screw for causing rotation of
the lead screw relative to the motor, and a longitudinal guide
extends parallel with the lead screw and receives the motor. The
guide allows longitudinal movement of the motor and prevents
rotation of the motor, so that actuation of the motor causes
longitudinal movement of the lead screw through the fixed nut.
According to another aspect, the rotary motor and the longitudinal
guide have non-circular cross-sections preventing rotation of the
motor with respect to the guide.
[0022] According to an additional aspect of the present invention,
a reflector is secured for longitudinal movement with the lead
screw, at least one light emitter is fixed with respect to the lead
screw and directed longitudinally at the reflector, and at least
one light detector is fixed with respect to the lead screw and
directed longitudinally at the reflector. According to one aspect,
the reflector is oriented at an angle with respect to the guide of
the motor. A processor is connected to the light emitter and the
light detector and programmed to determine a longitudinal distance
of the reflector from the light emitter based upon a lateral
distance between a beam of light directed from the light emitter to
the reflector and the beam of light as received by the light
detector from the reflector. According to another aspect, the
reflector is secured to the motor.
[0023] According to yet another aspect of the present invention, at
least one light emitter is directed laterally within the
longitudinal guide, at least one light detector is directed
laterally within the longitudinal guide, and one of the guide and
the motor is relatively light reflective. In this manner, the light
detector can provide a signal indicative of longitudinal movement
of the motor with the lead screw and within the longitudinal
guide.
[0024] According to yet another aspect of the present invention,
the lead screw is made from electrically resistive material and the
fixed nut is made from electrically conductive material. A
processor is connected to the nut and the lead screw and programmed
to detect an electrical signal between the nut and the lead screw.
The processor is further programmed to determine a relative
longitudinal position between the nut and the lead screw based on
one of the electrical signal and changes to the electrical
signal.
[0025] According to still an additional aspect of the present
invention, the device further includes teeth secured to the tube
and a pawl engaging the teeth of the tube and allowing rotation of
the tube in a single direction. The teeth can be unitarily formed
with the tube in order to simplify manufacturing.
[0026] These aspects of the invention together with additional
features and advantages thereof may best be understood by reference
to the following detailed descriptions and examples taken in
connection with the accompanying illustrated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of a first exemplary embodiment
of a fluid delivery device constructed in accordance with the
present invention and shown secured on a patient, and a remote
control device for use with the fluid delivery device (the remote
control device being enlarged with respect to the patient and the
fluid delivery device for purposes of illustration);
[0028] FIGS. 2a and 2b are enlarged top and bottom perspective
views, respectively, of the fluid delivery device of FIG. 1;
[0029] FIG. 3 is a further enlarged top perspective view of the
fluid delivery device of FIG. 1, shown with a top housing portion
removed to reveal interior portions of the fluid delivery device,
including an exemplary embodiment of a lead screw assembly
constructed in accordance with the present invention;
[0030] FIG. 4 is a further enlarged perspective view of the lead
screw assembly of the fluid delivery device of FIG. 1;
[0031] FIG. 5 is another perspective view of the lead screw
assembly of the fluid delivery device of FIG. 1;
[0032] FIG. 6a is a further perspective view of a portion of the
lead screw assembly of the fluid delivery device of FIG. 1,
including an exemplary embodiment of a fixed nut assembly
constructed in accordance with the present invention;
[0033] FIG. 6b is another perspective view of the fixed nut
assembly of the fluid delivery device of FIG. 1;
[0034] FIG. 6c is an exploded, perspective view of portions of the
fixed nut assembly of the fluid delivery device of FIG. 1;
[0035] FIG. 7a is a further enlarged top perspective view of a
portion of the fluid delivery device of FIG. 1, shown with the top
housing portion removed to reveal interior portions of the fluid
delivery device, including the lead screw assembly and exemplary
embodiments of a set of pawls and a ratchet member constructed in
accordance with the present invention;
[0036] FIG. 7b is a further enlarged perspective view of the
ratchet member of the fluid delivery device of FIG. 1;
[0037] FIG. 7c is a further enlarged, opposite perspective view of
the set of pawls of the fluid delivery device of FIG. 1;
[0038] FIG. 8 is a schematic illustration of components of an
exemplary embodiment of a fluid delivery device constructed in
accordance with the present invention and including a lead screw
and a sensor for providing signals indicative of longitudinal
movement of the lead screw;
[0039] FIG. 9 is a schematic illustration of an exemplary
embodiment of sensor assembly constructed in accordance with the
present invention for providing an indication of rotation of a gear
of a fluid delivery device, such as the fluid delivery device of
FIG. 3;
[0040] FIG. 10 is a side elevation view of another exemplary
embodiment of sensor assembly constructed in accordance with the
present invention for providing an indication of rotation of a gear
of a fluid delivery device, such as the fluid delivery device of
FIG. 3;
[0041] FIG. 11 is an end elevation view of the gear of FIG. 10;
[0042] FIG. 12 is a perspective view of an exemplary embodiment of
sensor assembly constructed in accordance with the present
invention for providing an indication of rotation of a lead screw
assembly of a fluid delivery device, such as the fluid delivery
device of FIG. 3;
[0043] FIG. 13 is a side elevation view of the sensor assembly and
the lead screw assembly of FIG. 12;
[0044] FIG. 14 is a side elevation view of another exemplary
embodiment of sensor assembly constructed in accordance with the
present invention for providing an indication of rotation of a lead
screw assembly of a fluid delivery device, such as the fluid
delivery device of FIG. 3;
[0045] FIG. 15 is an end elevation view of an encoder disk of the
sensor assembly of FIG. 14;
[0046] FIGS. 16 and 17 are schematic illustrations of another
exemplary embodiment of a fluid delivery device constructed in
accordance with the present invention, and illustrating operation
of a lead screw assembly and motion sensor assemblies of the fluid
delivery device;
[0047] FIG. 18 is an enlarged view of a light emitter/detector of
the motion sensor assembly of the fluid delivery device of FIGS. 16
and 17, as contained in circle 18 of FIG. 17;
[0048] FIG. 19 is a schematic illustration of a further exemplary
embodiment of a fluid delivery device constructed in accordance
with the present invention, and including a lead screw assembly and
motion sensor assemblies;
[0049] FIG. 20 is a schematic illustration of another exemplary
embodiment of a fixed nut assembly and a lead screw constructed in
accordance with the present invention, for use with a fluid
delivery device such as the fluid delivery device of FIG. 3;
[0050] FIG. 21 is an end perspective view of a portion of another
exemplary embodiment of a lead screw assembly constructed in
accordance with the present invention, for use with a fluid
delivery device such as the fluid delivery device of FIG. 3;
[0051] FIG. 22 is an end perspective view of a portion of a further
exemplary embodiment of a lead screw assembly constructed in
accordance with the present invention, for use with a fluid
delivery device such as the fluid delivery device of FIG. 3;
[0052] FIG. 23 is an end elevation view of another exemplary
embodiment of a ratchet member constructed in accordance with the
present invention, for turning a lead screw of a fluid delivery
device such as the fluid delivery device of FIG. 3;
[0053] FIG. 24 is an end elevation view of a further exemplary
embodiment of a ratchet member constructed in accordance with the
present invention, for turning a lead screw of a fluid delivery
device such as the fluid delivery device of FIG. 3;
[0054] FIG. 25 is a top plan view of an exemplary embodiment of a
lead screw, a plunger a reservoir, and a housing portion
constructed in accordance with the present invention, for use with
a fluid delivery device;
[0055] FIG. 26 is a sectional view of the lead screw and the
housing portion taken along line 26-26 of FIG. 25;
[0056] FIG. 27 is a sectional view of another exemplary embodiment
of a lead screw and corresponding housing portions constructed in
accordance with the present invention; and
[0057] FIG. 28 is an end perspective view of an additional
exemplary embodiment of a lead screw and corresponding housing
portions constructed in accordance with the present invention.
[0058] Like reference characters designate identical or
corresponding components and units throughout the several
views.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0059] Referring to FIGS. 1 through 3, there is illustrated an
exemplary embodiment of a fluid delivery device 10 constructed in
accordance with the present inventions. Referring to FIG. 3, the
fluid delivery device 10 includes exemplary embodiments of a lead
screw assembly 12, a ratchet member 14 for turning the lead screw
assembly 12, a set of pawls 16 for allowing rotation of the lead
screw assembly 12 in a single direction, a fixed nut assembly 18
engaging the lead screw assembly 12, and a sensor assembly 20 for
monitoring longitudinal movement of the lead screw assembly 12. All
of these exemplary embodiments are constructed in accordance with
the present invention.
[0060] Referring to FIG. 3, the fluid delivery device 10 also
includes exemplary embodiments of a reservoir 22 for receiving and
holding fluid to be delivered by the device 10, a transcutaneous
access tool 24 for providing fluid communication between the
reservoir 22 and a patient, and a laminated flow path assembly 26
connecting a fill port 28 to the reservoir 22 and the reservoir 22
to the transcutaneous access tool 24. These components are
described in detail in co-pending U.S. application Ser. No.
10/260,192, which is assigned to the assignee of the present
application, and has previously been incorporated herein by
reference.
[0061] The fluid delivery device 10 can be used for the delivery of
fluids to a person or animal. The types of liquids that can be
delivered by the fluid delivery device 10 include, but are not
limited to, insulin, antibiotics, nutritional fluids, total
parenteral nutrition or TPN, analgesics, morphine, hormones or
hormonal drugs, gene therapy drugs, anticoagulants, analgesics,
cardiovascular medications, AZT or chemotherapeutics. The types of
medical conditions that the fluid delivery device 10 might be used
to treat include, but are not limited to, diabetes, cardiovascular
disease, pain, chronic pain, cancer, AIDS, neurological diseases,
Alzheimer's Disease, ALS, Hepatitis, Parkinson's Disease or
spasticity. The volume of the reservoir 22 is chosen to best suit
the therapeutic application of the fluid delivery device 10
impacted by such factors as available concentrations of medicinal
fluids to be delivered, acceptable times between refills or
disposal of the fluid delivery device 10, size constraints and
other factors.
[0062] In the exemplary embodiment shown in FIG. 3, the reservoir
22 includes a cylindrical side wall 30 extending towards an outlet
32 connected to the transcutaneous access tool 24. The lead screw
assembly 12 includes a threaded lead screw 34 received in the
reservoir 22 and extending towards the outlet 32 of the reservoir
22 generally parallel with the side wall 30 of the reservoir 22. A
plunger 36 is secured to an end of the lead screw 34. The lead
screw 34, the plunger 36 and the reservoir 22 are adapted (e.g.,
provided with o-rings) such that a fluid-tight seal is formed
between the plunger 36 and the lead screw 34 and a fluid-tight seal
is formed between the plunger 36 and the side wall 30 of the
reservoir 22, so that movement of the plunger 36 towards the outlet
32 of the reservoir 22 forces fluid through the outlet 32 to the
transcutaneous access tool 24.
[0063] As shown in FIG. 7a, the device 10 includes an actuator in
the form of an elongated shape memory element 38 operatively
connected to a processor 40 of the fluid delivery device such that
electrical charges can be applied to the shape memory element based
on commands from the processor. The shape memory element 38 has a
changeable length decreasing from an uncharged length to a charged
length when at least one charge is applied to the shape memory
element 38, and is operatively connected to the lead screw assembly
12 through the ratchet member 14 such that the changeable length of
the shape memory element 38 causes longitudinal movement of the
lead screw 34 so that the plunger 36 moves along the side wall 30
of the reservoir 22.
[0064] In the exemplary embodiment shown in FIG. 3, a rotatable
gear 42 is coaxially fixed to an exterior surface of a slotted tube
44 of the lead screw assembly 12 such that rotation of the gear 42
causes rotation of the slotted tube 44 about a common longitudinal
axis "A". The lead screw 34 is coaxially positioned within the
slotted tube 44 and includes a radially extending pin 46 slidingly
received in longitudinal slots 48 of the slotted tube 44 such that
rotation of the slotted tube 44 causes rotation of the lead screw
34. The lead screw 34 is also threadedly engaged with the fixed nut
assembly 18, which is non-rotating with respect to the lead screw
34 and is linearly fixed in position with respect to the reservoir
22. Rotation of the gear 42 causes linear movement of the lead
screw 34 through the fixed nut assembly 18 and linear movement of
the plunger 36 towards the outlet 32 of the reservoir 22.
[0065] The ratchet member 14 engages radially extending teeth of
the gear 42, and the ratchet member 14 and the gear 42 are adapted
such that linear movement of the ratchet member 14 in a first
direction adjacent the gear 42 causes rotation of the gear 42,
while linear movement of the ratchet member 14 in a second
direction adjacent the gear 42 causes no rotation of the gear 42.
The elongated shape memory element 38, shown in FIG. 7a, is
connected to the ratchet member 14 such that the changeable length
of the shape memory element 38 decreasing from an uncharged length
to a charged length causes linear movement of the ratchet member 14
in one of the first and the second directions. A spring 50, as
shown best in FIG. 7a, is connected to the ratchet member 14 for
causing linear movement of the ratchet member 14 in the other of
the first and the second directions. In the exemplary embodiment
shown, the spring comprises a hinge spring 50.
[0066] The processor 40 (hereinafter referred to as the "local"
processor) is electrically connected to the shape memory element 38
and is programmed to apply charges to the shape memory element in
order to cause a flow of fluid to the transcutaneous access tool
24, based on flow instructions from a separate, remote control
device 1000, an example of which is shown in FIG. 1. A wireless
receiver 52 is connected to the local processor 40 for receiving
flow instructions from the remote control device 1000 and
delivering the flow instructions to the local processor 40. The
device 10 also includes a housing 54 containing the lead screw
assembly 12, the ratchet member 14, the set of pawls 16, the fixed
nut assembly 18, the sensor assembly 20, the flow path assembly 26,
the transcutaneous access tool 24, the reservoir 22, the local
processor 40, and the wireless receiver 52.
[0067] As shown best in FIGS. 2a and 2b, the housing 54 of the
fluid delivery device 10 is free of user input components for
providing flow instructions to the local processor 40, such as
electromechanical switches or buttons on an outer surface of the
housing 54, or interfaces otherwise accessible to a user to adjust
the programmed flow rate through the local processor 40. The lack
of user input components allows the size, complexity and costs of
the device 10 to be substantially reduced so that the device 10
lends itself to being small and disposable in nature. Examples of
such devices are disclosed in co-pending U.S. patent application
Ser. No. 09/943,992, filed on Aug. 31, 2001, and entitled DEVICES,
SYSTEMS AND METHODS FOR PATIENT INFUSION, which is assigned to the
assignee of the present application and has previously been
incorporated herein by reference.
[0068] In order to program, adjust the programming of, or otherwise
communicate user inputs to the local processor 40, the fluid
delivery device 10 includes the wireless communication element 52,
as shown in FIG. 3, for receiving the user inputs from the
separate, remote control device 1000 of FIG. 1. Signals can be sent
via a communication element (not shown) of the remote control
device 1000, which can include or be connected to an antenna 1300,
shown in FIG. 1 as being external to the device 1000.
[0069] The remote control device 1000 has user input components,
including an array of electromechanical switches, such as the
membrane keypad 1200 shown. The remote control device 1000 also
includes user output components, including a visual display, such
as a liquid crystal display (LCD) 1 100. Alternatively, the control
device 1000 can be provided with a touch screen for both user input
and output. Although not shown in FIG. 1, the remote control device
1000 has its own processor (hereinafter referred to as the "remote"
processor) connected to the membrane keypad 1200 and the LCD 1 100.
The remote processor receives the user inputs from the membrane
keypad 1200 and provides "flow" instructions for transmission to
the fluid delivery device 10, and provides information to the LCD 1
100. Since the remote control device 1000 also includes a visual
display 1100, the fluid delivery device 10 can be void of an
information screen, further reducing the size, complexity and costs
of the device 10.
[0070] The communication element 52 of the device 10 preferably
receives electronic communication from the remote control device
1000 using radio frequency or other wireless communication
standards and protocols. In a preferred embodiment, the
communication element 52 is a two-way communication element,
including a receiver and a transmitter, for allowing the fluid
delivery device 10 to send information back to the remote control
device 1000. In such an embodiment, the remote control device 1000
also includes an integral communication element comprising a
receiver and a transmitter, for allowing the remote control device
1000 to receive the information sent by the fluid delivery device
10.
[0071] The local processor 40 of the device 10 contains all the
computer programs and electronic circuitry needed to allow a user
to program the desired flow patterns and adjust the program as
necessary. Such circuitry can include one or more microprocessors,
digital and analog integrated circuits, resistors, capacitors,
transistors and other semiconductors and other electronic
components known to those skilled in the art. The local processor
40 also includes programming, electronic circuitry and memory to
properly activate the shape memory element 38 at the needed time
intervals.
[0072] In the exemplary embodiment of FIG. 3, the device 10 also
includes a power supply, such as a battery or capacitor 56, for
supplying power to the local processor 40. The power supply 56 is
preferably integrated into the fluid delivery device 10, but can be
provided as replaceable, e.g., a replaceable battery. The device 10
can also include sensors or transducers such as a flow condition
sensor assembly 58, for transmitting information to the local
processor 40 to indicate how and when to activate the shape memory
element 38, or to indicate other parameters determining fluid flow,
as well as conditions such as the reservoir 22 being empty or
leaking, or the dispensing of too much or too little fluid from the
reservoir 22, etc.
[0073] As shown in FIG. 2b, the device 10 can also be provided with
an adhesive layer 60 on the outer surface of the housing 54 for
securing the device 10 directly to the skin of a patient, as
illustrated in FIG. 1. The adhesive layer 60 is provided on an
external "bottom" surface of the housing 54. The adhesive layer 60
is also preferably provided in a continuous ring encircling an
external exit port 62 of the housing 54 in order to provide a
protective seal around the penetrated patient's skin to prevent the
penetrated skin from becoming contaminated when a cannula 64 of the
transcutaneous access tool 24 extends through the skin. It is
preferable that the fill port 28 extend through the bottom surface
of the housing 54 and be surrounded by the adhesive layer 60 to
discourage and prevent filling and re-filling of the fluid delivery
device 10 when the device is attached to a patient's skin. The
housing 54 can be made from flexible material, or can be provided
with flexible hinged sections that allow the fluid delivery device
10 to flex during patient movement to prevent detachment and aid in
patient comfort.
[0074] The sensor assembly 20 monitoring longitudinal movement of
the lead screw 34 includes a reference element 66 secured to the
pin 46 of the lead screw 34, at least one light emitter directed
laterally at the tube 44 for directing a beam of light at the tube
44, and at least one light detector directed laterally at the tube
44 for receiving the beam of light reflected away from the tube 44.
In the exemplary embodiment of FIGS. 3 and 4, the light emitter and
the light detector are provided as part of a single component,
i.e., a light emitter/detector 68. In addition, one of the tube 44
and the reference element 66 has a light reflective outer surface,
so that the detector 68 provides a signal upon movement of the
reference element past the detector. In the exemplary embodiment
shown in FIGS. 3 through 5, the reference element 66 has a light
reflective outer surface. In addition, the reference element 66 is
annular and coaxially received for sliding movement along an outer
surface of the tube 44. Moreover, as shown in FIGS. 3 and 4, the
sensor assembly 20 includes three of the emitter/detectors 68.
[0075] This configuration provides absolute position information
regarding the lead screw 34 and thus the plunger position. When a
signal is received indicating that the reference element 66 has
been detected by detector 68, the information is interpreted as to
a specific amount of fluid residing in the reservoir. Multiple
detectors, such as detector 68, can be utilized to provide multiple
levels of reservoir volume (absolute position of lead screw). For
example, one detector can be positioned at a relatively low volume
to indicate to the user the pump is near empty. An opposite
configuration can be employed, wherein a single detector
(relatively more expensive than the reference element) is secured
for movement to the pin 46 and one or more reference elements 66
are directed laterally at the tube. In a exemplary embodiment, the
detector is annular and coaxially received for sliding movement
along the outer surface of the tube 44. This configuration requires
(moving) wires connected to the detector.
[0076] The fixed nut assembly 18 is configured to be disengaged
from the lead screw 34 prior to use of the device 10 to allow the
lead screw 34 and the plunger 36 to be linearly moved away from an
inlet 33 of the reservoir 22 during filling of the reservoir 22
through the fill port 18. Referring also to FIGS. 5, 6a, 6b and 6c,
the exemplary embodiment of the fixed nut assembly 18 includes at
least two laterally movable threaded inserts 70 including threaded
surfaces for threadedly receiving the lead screw 34 upon being
biased laterally inwardly against the lead screw 34, a spring 72
biasing the threaded inserts 70 laterally inwardly against the lead
screw 34, and at least one spacer cam 74 movable between a first
position preventing the threaded inserts 70 from being biased
laterally inwardly against the lead screw 34 and a second position
allowing the threaded inserts 70 to be biased laterally inwardly
against the lead screw 34.
[0077] In the exemplary embodiment of FIGS. 6a, 6b and 6c, the
spacer cams 74 are laterally movable with respect to the lead screw
34, and are adapted so that, in the first position, the spacer cams
74 are positioned between the threaded inserts 70. Preferably, the
spacer cams 74 are operatively connected to the gear 42 such that
rotation of the gear 42 causes movement of the spacer cams 74 to
the second position. In this manner, the initial rotation of the
gear 42, when the device 10 is first used (i.e., powered-up or
started), can be used to engage the nut assembly 18 and the lead
screw 34, such that further rotation of the gear 42 causes linear
movement of the lead screw 34.
[0078] The nut assembly 18 also includes a gear cam 76 operatively
connected with the gear 42 for rotation with the gear 42 about the
lead screw 34, and a spacer follower 78 laterally moveable with
respect to the lead screw 34. The spacer follower 78 is connected
to the spacer cams 74 such that lateral movement of the spacer
follower 78 in a first direction with respect to the lead screw 34
causes movement of the spacer cams 74 to the second position. The
spacer follower 78 is received against the gear cam 76 and the gear
cam 76 and the spacer follower 78 are shaped such that rotation of
the gear cam 76 about the lead screw 34 (i.e., rotation of the gear
42) causes lateral movement of the spacer follower 78 in the first
direction with respect to the lead screw 34.
[0079] In the exemplary embodiment shown in FIGS. 6a, 6b and 6c,
the spacer follower 78 and the spacer cams 74 are connected through
a spacer ring 80 coaxially positioned with respect to the lead
screw 34. In addition, the gear cam 76 is provided as part of a
gear ring 82 coaxially positioned with respect to the lead screw 34
and including at least one spline 84 extending into a keyway 86 of
the gear 42. The gear cam 76 is formed in a radially outwardly
facing surface of one of the splines 84.
[0080] As shown best in FIGS. 5 and 6a, the gear ring 82 also
includes a latch 88 allowing the spacer follower 78 to exit the
gear cam 76 and preventing the spacer follower 78 from re-entering
the gear cam 76. In this manner, after the gear 42 is initially
turned, the nut assembly 18 engages the lead screw 34 and remains
engaged with the lead screw 34 even upon one or more full rotations
of the gear 42.
[0081] Another exemplary embodiment of a nut assembly 90
constructed in accordance with the present invention is shown in
FIG. 20. The nut assembly 90 includes at least two laterally
movable threaded inserts 92 having threaded surfaces for threadedly
receiving the lead screw 34 upon being biased laterally inwardly
against the lead screw, springs 94 biasing the threaded inserts 92
laterally inwardly against the lead screw 34, and spacer cams 96.
The spacer cams 96 are movable in a longitudinal direction with
respect to the lead screw 34 between a first position preventing
the threaded inserts 92 from being biased laterally inwardly
against the lead screw, as shown in FIG. 20, and a second position
allowing the threaded inserts 92 to be biased laterally inwardly
against the lead screw. It is intended that the spacer cams 96 can
be adapted to be manually moved to the second position by a user
once the user has filled the reservoir. In one possible embodiment,
the spacer cams 96 may have an extension portion that extends out
of the housing of the fluid delivery device for manual movement of
the spacer cams 96 by a user.
[0082] It should be understood, however, that other mechanisms can
be employed which have one or more threaded parts which are not
initially engaged with, or can be disengaged from, the lead screw
34 and that allow linear motion of the lead screw without requiring
rotation of the lead screw, and that later can be engaged with the
lead screw 34 to allow linear motion of the lead screw only upon
rotation of the lead screw. Engagement and disengagement of the
lead screw 34 can be accomplished as described above, or by other
means such as via a linear actuator (e.g. an shape memory element
"pulls" the threaded member(s) away from the lead screw to allow
freedom of movement of the lead screw during filling of the
reservoir).
[0083] Referring now to FIGS. 3, 7a and 7b, the ratchet member 14
includes a ratchet 100 engaging teeth of the gear 42, at least one
anchor 102 fixed in position with respect to the gear 42, and at
least one spring 104 biasing the ratchet 100 in the second
direction and away from the anchor 102. The springs 104 comprise
bent portions of flat sheet material. The ratchet 100 is connected
to the springs 104 through a flat extension portion 106, which also
is biased away from the anchors 102 by the springs 104. The flat
extension portion 106 also includes bosses 108, 109 for connection
to the shape memory element 38 and the ratchet spring 50. The
ratchet member 14 is preferably formed from a single piece of sheet
metal, which is cut, bent and folded to form the anchors 102, the
springs 104, flat extension portion 106, the ratchet 100 and the
bosses 108, 109. In the exemplary embodiment shown, the shape
memory element 38 is arranged such that the changeable length of
the shape memory element decreasing from an uncharged length to a
charged length causes movement of the ratchet 100 in the first
direction. The hinge spring 50 is arranged to bias the ratchet 100
in the second direction.
[0084] Referring back to FIGS. 7a and 7c, the set of pawls 16
includes at least two pawls 110 engaging teeth of the gear 42 and
allowing rotation of the gear 42 in a single direction. The pawls
110 allow rotation of the gear 42, and thus the tube 44 and the
lead screw 34, in a single direction, which in the exemplary
embodiment of FIG. 7a is shown as being clockwise. Among other
features and benefits, the deployment of at least two pawls 110
provides redundancy in case one of the pawls 110 snaps or otherwise
fails during operation of the device. According to one exemplary
embodiment, the pawls 110 are adapted and arranged such that the
pawls 110 allow rotation of the gear equal to less than a tooth
pitch of the gear. For example in one embodiment, the pawls 110 are
provided with the same length, but are arranged to be out of phase
by a single tooth pitch in order to allow rotation of the gear
equal to less than a tooth pitch of the gear. According to another
exemplary embodiment, the pawls 110 are arranged to be in phase but
are provided with different lengths in order to allow rotation of
the gear equal to less than a tooth pitch of the gear.
[0085] Referring now to FIG. 8, an embodiment of the present
invention is provided with a sensor 112 detecting linear movement
of the lead screw 34. The sensor 112 can be provided in many forms,
such as the optical emitter/detectors 68 of FIGS. 3 and 4, for
providing a signal indicative of longitudinal movement of the lead
screw 34. Longitudinal movement of the lead screw 34 towards the
outlet 32 of the reservoir 22, of course, indicates a corresponding
movement of the plunger 36 and the dispensing of fluid from the
reservoir to the transcutaneous access tool 24.
[0086] The processor 40 is connected to the sensor 112 and
programmed to apply a charge to the shape memory element 38 (as
generally based upon the desire fluid flow as programmed by a user
through the remote control device), and remove the charge upon
receiving a signal from the sensor 112 indicative of a desired
amount, preferably a minimum amount, of linear movement of the lead
screw 34. In this manner, power is applied to the shape memory
element 38 only for as long as needed to cause movement of the lead
screw 34 as desired. In an alternative, preferred embodiment, a
construction is employed, some of which are described herebelow,
which detects a desired amount of rotation of the lead screw prior
to removing the charge from the shape memory element 38. The
addition of the sensor 112 and the programming of the processor 40
results in a reduction in power usage by the fluid delivery device
10, since power is only applied to the shape memory element 38 for
a period necessary to advance the plunger 36 by a desired amount
(i.e. the efficiency of the drive system is improved by minimizing
power loss to the shape memory component).
[0087] FIG. 9 shows an embodiment of a sensor assembly 114
constructed in accordance with the present invention for providing
signals indicating rotation of the gear 42. Rotation of the gear
42, in turn, provides an indication of longitudinal movement of the
lead screw 34. The sensor assembly 114 includes a first electrical
lead 116 connected to the gear 42, a second electrical lead 118
connected to the ratchet 100, and a third electrical lead 120
connected to the pawl 1 10. In the embodiment of FIG. 9, the gear
42, the ratchet 100, and the pawl 110 are made from electrically
conductive material. The processor 40 is connected to the first,
the second and the third electrical leads 116, 118, 120 and
programmed to determine whether the gear 42 has been rotated based
at least in part on electrical discontinuities between the ratchet
100, the gear 42, and the pawl 110 (i.e., opening and closing of
the circuit formed between the ratchet, the gear, and the pawl as
the gear rotates).
[0088] FIGS. 10 and 11 show another exemplary embodiment of a
sensor assembly 122 constructed in accordance with the present
invention for use as part of a fluid delivery device, such as the
fluid delivery device 10 of FIG. 3. The sensor assembly 122 can be
used to provide an indirect indication of longitudinal movement of
a lead screw 124, and includes a gear 126 and an electrically
conductive brush 128 biased against a face 130 of the gear. The
gear 126 is intended to be operatively connected to the lead screw
124, similar to the gear 42 and the lead screw 34 of FIG. 3 for
example. Rotation of the gear 126, accordingly, causes longitudinal
movement of the lead screw 124.
[0089] As shown, the face 130 of the gear 126 includes radially
spaced bumps 132 thereon. One of the face 130 and the bumps 132 are
electrically conductive. In the exemplary embodiment shown, an
opposite, second face 134 of the gear 126 is made from, or covered
by electrically conductive material, and a second electrically
conductive brush 136 is biased against the second face 134 of the
gear. Both brushes 128, 136 are then connected to a processor 40
which is programmed to determine whether the gear 126 has rotated
based at least in part on electrical discontinuities between the
brushes 128, 136 and the gear (i.e., opening and closing of the
circuit formed between the brush 128 and the bumps 132 of the gear
126 as the gear rotates). In the exemplary embodiment shown in
FIGS. 10 and 11, the radially spaced bumps 132 are made of
conductive material and correspond to outer circumferential teeth
138 of the gear 126.
[0090] FIGS. 12 and 13 show a further exemplary embodiment of
sensor assembly 140 constructed in accordance with the present
invention for use as part of a fluid delivery device, such as the
fluid delivery device 10 of FIG. 3. The sensor assembly 140 can be
used to provide an indirect indication of longitudinal movement of
the lead screw 34, and includes an encoder disk 142 coaxially
secured to the tube 44 and including radially spaced light
reflective indicia 144 thereon. A light emitter is directed at the
encoder disk, and a light detector directed at the encoder disk. In
the exemplary embodiment shown, the light emitter and the light
detector are combined in a single light emitter/detector 146. The
light emitter/detector 146 is connected to the processor (not
shown) of the fluid delivery device, which is in-turn programmed to
determine the amount of rotation of the tube 44, and thus the
connected gear 42 and the lead screw 34. In the exemplary
embodiment of FIGS. 12 and 13, the radially spaced light reflective
indicia 144 is located on an outer circumferential surface of the
encoder disk 142.
[0091] FIGS. 14 and 15 show still another exemplary embodiment of
sensor assembly 150 including an encoder disk 152 coaxially secured
to the tube 44 and including radially spaced light reflective
indicia 154 thereon. A light emitter/detector 156 is directed at
the encoder disk 152, and is connected to the processor (not shown)
of the fluid delivery device. The processor is in-turn programmed
to determine the amount of rotation of the tube 44, and thus the
connected gear 42 and the lead screw 34. In the exemplary
embodiment of FIGS. 14 and 15, the radially spaced light reflective
indicia 154 is located on an outer circumferential surface of the
encoder disk 152. In addition, the encoder disk 152 is secured to
the gear 42 and includes a recess 158 on a face thereof for
receiving the annular reference element 66 (which is secured to the
lead screw 34) in a nested manner upon the lead screw 34 being
fully moved into the reservoir.
[0092] FIGS. 16 and 17 show another fluid delivery device 160
constructed in accordance with the present invention. The fluid
delivery device 160 is generally similar to the fluid delivery
device 10 of FIG. 3 such that similar elements have the same
reference numerals. The fluid delivery device 160 of FIGS. 16 and
17, however, includes a lead screw 162 extending through a fixed,
non-rotatable nut 164, and a rotary motor 166 mated to a proximal
end of the lead screw 162 for causing rotation of the lead screw
relative to the motor. A longitudinal guide 168 extends parallel
with the lead screw 162 and receives the motor 166. The guide 168
allows longitudinal movement of the motor 166 and prevents rotation
of the motor, so that actuation of the motor causes longitudinal
movement of the lead screw 162 through the fixed nut 164. In the
exemplary embodiment shown, the rotary motor 166 and the
longitudinal guide 168 have non-circular cross-sections preventing
rotation of the motor with respect to the guide.
[0093] The device 160 also includes a sensor assembly 170 having a
reflector 172 secured to the lead screw 162 for longitudinal
movement therewith (i.e. longitudinally moves in an amount the same
as or related to the lead screw motion), and at least one light
emitter 174 fixed with respect to the lead screw and directed
longitudinally at the reflector 172, and at least one light
detector 176 fixed with respect to the lead screw 162 and directed
longitudinally at the reflector 172. An enlarged view of the light
emitter 174 and the light detector 176 is shown in FIG. 18. As
shown in FIGS. 16 and 17, the reflector 172 is oriented at an angle
with respect to the guide 168 of the motor 166. In addition, the
reflector 172 is secured to the lead screw 162 through the motor
166. Alternatively, the motor 166 can perform the function of the
reflector 172, thereby eliminating one or more parts.
[0094] The processor 40 of the fluid delivery device 160 is
connected to the light emitter 174 and the light detector 176 and
is programmed to determine a longitudinal distance of the reflector
172 from the light emitter 174 based upon a lateral distance
between a beam of light directed from the light emitter 174 to the
reflector 172 and the beam of light as received by the light
detector 176 from the reflector. As shown in FIGS. 16 and 17, the
lateral distance increases as the longitudinal distance increases.
The longitudinal distance may be based on one or more parameters
such as the amount, or intensity, of light detected, or other
parameters related to other properties of light, such as angle of
incidence, quantities or properties of the different components of
(white) light, etc. Also, in a preferred embodiment, the system
provides a gross estimation of longitudinal position, but also
provides a much finer resolution on relative motion since it is
easier to measure a change in linear position versus a change in
absolute position of the lead screw.
[0095] FIG. 19 shows another fluid delivery device 180 constructed
in accordance with the present invention. The fluid delivery device
180 is similar to the fluid delivery device 160 of FIGS. 16 and 17
such that similar elements have the same reference numerals. The
fluid delivery device 180 of FIG. 19, however, includes a sensor
assembly including at least one light emitter/detector 182 directed
laterally within the longitudinal guide 168. One of guide 168 and
the motor 166 is relatively light reflective. In the exemplary
embodiment shown, the motor 166 is relatively reflective and the
device 180 includes a plurality of the light emitter/detectors 182
spaced longitudinally within the guide 168.
[0096] In the exemplary embodiments 160, 180 of FIGS. 16, 17 and
19, the lead screw 162 is made from electrically resistive, or
other semi-conductive property material and the fixed nut 164 is
made from electrically conductive, or other semi-conductive
property material. The processor 40 is connected to the nut 164 and
the lead screw 162 and programmed to detect an electrical signal
between the nut and the lead screw. The processor 40 is further
programmed to determine a relative position between the nut 164 and
the lead screw 162 based on one of the electrical signal and
changes to the electrical signal. In this manner, the lead screw
162 and the nut 164 can be used as another sensor assembly for
monitoring the longitudinal position of the lead screw 162.
[0097] FIGS. 21 and 22 show exemplary embodiments of tubes 200,
210, respectively, for use as part of lead screw assemblies similar
to the lead screw assembly 12 of FIGS. 3, 4 and 5. The tubes 200,
210 are similar to the tube 44 of FIGS. 3, 4 and 5, but further
include teeth 202, 212 secured to the tubes 200, 210. As shown in
FIGS. 21 and 22, pawls 204, 214 are arranged to engage the teeth
202, 212 of the tubes 200, 210 and allow rotation of the tubes in a
single direction. In the exemplary embodiment of FIG. 21, the teeth
202 of the tube 200 are radially arranged on an end wall 206 of the
tube. In the exemplary embodiment of FIG. 22, the teeth 212 of the
tube 210 are circumferentially arranged on a side wall 216 of the
tube. Preferably, the teeth 202, 212 of the tubes 200, 210 are
unitarily formed as a single piece with the tubes. For example, the
teeth 202, 212 of the tubes 200, 210 are molded as part of the
tubes if the tubes are made from plastic.
[0098] Another exemplary embodiment of a ratchet member 220
constructed in accordance with the present invention is shown in
FIG. 23. The ratchet member 220 of FIG. 23 operates similar to the
ratchet member 14 of FIGS. 7a and 7b to turn the gear 42 and the
lead screw 34 and advance the plunger in the reservoir. The ratchet
member 220 of FIG. 23, however, includes spaced-apart feet 222
movable in first and second opposing directions with respect to the
gear 42, a resiliently flexible arch 224 extending between the
spaced-apart sliding feet 222 and towards the gear 42, and a
ratchet 226 extending from the arch 224 and engaging teeth of the
gear 42 such that movement of the ratchet member 220 in the first
direction with respect to the gear causes rotation of the gear
while movement of the ratchet member in the second direction with
respect to the gear causes no rotation of the gear and causes
deflection of the arch 224 away from the gear. The ratchet member
220 is linearly moveable in the first and the second opposing
directions.
[0099] An elongated shape memory element 38 is secured to the
ratchet member 220. The elongated shape memory element 38 has a
changeable length decreasing from an uncharged length to a charged
length when at least one charge is applied to the shape memory
element. The shape memory element 38 is secured to the ratchet
member 220 such that the changeable length of the shape memory
element decreasing from an uncharged length to a charged length
causes movement of the ratchet member in one of the first and the
second directions. In the exemplary embodiment of FIG. 23, the
shape memory element 38 is arranged so that the changeable length
of the shape memory element decreasing from an uncharged length to
a charged length causes movement of the ratchet member 220 in the
first direction. The ratchet member 220 is biased in the second
direction by a ratchet spring 50.
[0100] A switch 228 is positioned with respect to the arch 224 of
the ratchet member 220 such that the arch 224 contacts the switch
228 upon deflection of the arch away from the gear 42 during
movement of the ratchet member 220 in the second direction with
respect to the gear 42. The switch 228 provides a signal upon being
contacted by the arch 224 of the ratchet member 220, and is
connected to the processor of the fluid delivery. The processor, in
turn, is programmed to determine that the gear 42 has been
adequately rotated upon receiving a signal from the switch 228.
[0101] A further exemplary embodiment of a ratchet member 230
constructed in accordance with the present invention is shown in
FIG. 24. The ratchet member 230 includes arms 232 pivotally secured
on the lead screw 34 on opposite sides of the gear 42, and a
ratchet 234 engaging teeth of the gear 42 such that pivotal
movement of the ratchet member 230 about the lead screw 34 in a
first direction causes rotation of the gear 42 while pivotal
movement of the ratchet member 230 about the lead screw 34 in a
second direction causes no rotation of the gear. In the exemplary
embodiment shown, the ratchet member 230 also includes an anchor
236 fixed in position with respect to the gear 42, and a spring 238
biasing the ratchet 234 in the second direction and towards the
anchor 236.
[0102] Additional exemplary embodiments of a threaded lead screw
250, a threaded gear 252, a plunger 254 and a reservoir 256
constructed in accordance with the present invention are shown in
FIGS. 25 and 26. The reservoir 256 includes a cylindrical side wall
258 extending towards an outlet 260, and the lead screw 250 is
received in the reservoir 256 and extends towards the outlet 260
generally parallel with the side wall 258 of the reservoir 256, and
the plunger 254 is secured to an end of the lead screw 250. The
lead screw 250, the plunger 254 and the reservoir 256 are adapted
such that a fluid-tight seal is formed between the plunger 254 and
the lead screw 250 and a fluid-tight seal is formed between the
plunger 254 and the side wall 258 of the reservoir 256, so that
movement of the plunger 254 towards the outlet 260 of the reservoir
256 forces fluid through the outlet. The gear 252 is rotatably and
threadedly received on the lead screw 250.
[0103] The lead screw 250 includes one of a longitudinal extending
groove 262 and a laterally extending pin 264, and a housing 266
containing the reservoir 256, the lead screw 250 and the plunger
254 includes the other of the longitudinal extending groove 262 and
the laterally extending pin 264. The laterally extending pin 264 is
slidingly received within the longitudinally extending groove 262
to allow longitudinal advancement of the lead screw 250 and prevent
rotation of the lead screw 250, so that rotation of the gear 252
causes longitudinally movement of the lead screw 250 and the
plunger 254 within the reservoir 256.
[0104] In the exemplary embodiment of FIGS. 25 and 26, the lead
screw 250 includes the longitudinally extending groove 262 and the
housing 266 includes the laterally extending pin 264. In the
exemplary embodiment of FIG. 27, a lead screw 268 includes two
longitudinally extending grooves 262 and the housing 266 includes
two laterally extending pins 264, with one pin 264 received in each
groove 262.
[0105] In the exemplary embodiment of FIG. 28, a lead screw 270
includes two laterally extending pins 272 and a housing 274
includes two longitudinally extending grooves 276, 278. The
longitudinally extending grooves 276, 278 are unitarily formed as
part of upper and lower portions 280, 282 of the housing 274.
[0106] As illustrated by the above described exemplary embodiments,
the present invention generally provides new and improved dispenser
components for a device for delivering fluid, such as insulin for
example, to a patient. It should be understood that the embodiments
described herein are merely exemplary and that a person skilled in
the art may make variations and modifications to the embodiments
described without departing from the spirit and scope of the
present invention. All such equivalent variations and modifications
are intended to be included within the scope of this invention as
defined by the appended claims.
* * * * *