US20050238507A1 - Fluid delivery device - Google Patents

Abstract

A fluid delivery device may include a fluid driving mechanism for driving fluid out of a reservoir and an actuating mechanism for actuating the driving mechanism. The fluid delivery device may also include one or more sensors for monitoring operation of the fluid delivery device. The fluid delivery device may also include a chassis providing mechanical and/or electrical connections between components of the fluid delivery device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/704291, filed on Nov. 7, 2003, which is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/128,205, which are assigned to the assignee of the present application and are incorporated herein by reference.
• This application is related to U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165) entitled CHASSIS FOR FLUID DELIVERY DEVICE, which is filed concurrently herewith, assigned to the assignee of the present application, and incorporated herein by reference.
TECHNICAL FIELD
• The present invention relates to fluid delivery devices and more particularly, to an infusion pump for delivering therapeutic liquids to a patient.
BACKGROUND INFORMATION
• Fluid delivery devices have numerous uses such as delivering a liquid medicine to a patient subcutaneously. In a patient with diabetes mellitus, for example, ambulatory infusion pumps have been used to deliver insulin to a patient. These ambulatory infusion pumps have the ability to offer sophisticated fluid delivery profiles including variable basal rates and bolus requirements. The ability to carefully control drug delivery can result in better efficacy of the drug and therapy and less toxicity to the patient.
• Some existing ambulatory infusion pumps include a reservoir to contain the liquid medicine and use electromechanical pumping or metering technology to deliver the liquid medicine via tubing to a needle and/or soft cannula that is inserted subcutaneously into the patient. These existing devices allow control and programming via electromechanical buttons or switches located on the housing of the device. The devices include visual feedback via text or graphic screens and may include alert or warning lights and audio or vibration signals and alarms. Such devices are typically worn in a harness or pocket or strapped to the body of the patient.
• Currently available ambulatory infusion devices are expensive, difficult to program and prepare for infusion, and tend to be bulky, heavy and very fragile. Preparing these devices for infusion can be difficult and require the patient to carry both the intended medication as various accessories. Many existing devices also require specialized care, maintenance, and cleaning to assure proper functionality and safety for their intended long-term use. Due to the complexity and high cost of existing devices many patients who would benefit from an ambulatory infusion pump are, nonetheless using inferior forms of therapy.
• Accordingly, there is a need for a fluid delivery device with a reduced size and complexity and that is relatively inexpensive to manufacture.
BRIEF DESCRIPTION OF THE DRAWINGS
• These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings wherein:
• FIG. 1 is a top view of a fluid delivery device consistent with one embodiment of the present invention.
• FIG. 2 is an exploded view of one embodiment of a fluid driving mechanism used in a fluid delivery device.
• FIG. 3 is a perspective view of the fluid driving mechanism shown inFIG. 2 assembled into a chassis.
• FIG. 4 is a perspective view of one embodiment of an actuating mechanism for a fluid delivery device.
• FIG. 5 is a plan view of the actuating mechanism shown inFIG. 4 actuating the fluid driving mechanism shown inFIG. 2.
• FIG. 6 is a schematic diagram of a fill sensor that may be used in a fluid delivery device consistent with one embodiment of the present invention.
• FIGS. 7A and 7B are schematic diagrams illustrating the operation of the fill sensor shown inFIG. 6 from a side view.
• FIGS. 8A and 8B are schematic diagrams illustrating the operation of a rotational sensor that may be used in a fluid delivery device consistent with one embodiment of the present invention.
• FIG. 9 is a perspective view of a chassis of a fluid deliver device with sensors positioned in the chassis consistent with one embodiment of the present invention.
• FIG. 10 is a perspective view of a fluid driving mechanism engaging the sensors in the chassis shown inFIG. 9.
• FIGS. 11A and 11B are schematic diagrams illustrating the operation of a thread engaging mechanism moving from a non-thread-engaging position to a thread engaging position consistent with one embodiment of the present invention.
• FIG. 12A is a perspective views of a thread engaging mechanism in a first position consistent with one embodiment of the present invention.
• FIG. 12B is a perspective views of a thread engaging mechanism ofFIG. 12A in a second position.
• FIG. 12C is a top views of a thread engaging mechanism ofFIG. 12A in a second position.
• FIG. 13 is an enlarged schematic side view of a drive wheel of a fluid delivery device consistent with one embodiment of the present invention.
• FIG. 14 is a schematic diagram of a fill sensor system that may be used in a fluid delivery device consistent with one embodiment of the present invention.
• FIGS. 15A, 15B and15C are schematic diagrams illustrating the operation of an alternative rotational sensor that may be used in a fluid delivery device consistent with one embodiment of the present invention.
• FIG. 16 is a bottom view of a fluid delivery device having a needle cap consistent with one embodiment of the present invention.
• FIG. 17 is a schematic view of an activation system for a fluid delivery device consistent with one embodiment of the present invention.
DETAILED DESCRIPTION
• Referring toFIG. 1, one embodiment of afluid delivery device200 is shown and described. In the exemplary embodiment, thefluid delivery device200 is used to subcutaneously deliver a fluid, such as a liquid medicine, to a person or an animal. Those skilled in the art will recognize that thefluid delivery device200 may be used to deliver other types of fluids. Thefluid delivery device200 may be used to delivery fluids in a controlled manner, for example, according to fluid delivery profiles accomplishing bolus requirements, continuous infusion and variable flow rate delivery.
• According to one embodiment, thefluid delivery device200 may include one ormore batteries210 for providing a power source, afluid reservoir230 for holding a fluid, afluid driving mechanism250 for driving the fluid out of thereservoir230, afluid passage mechanism270 for receiving the fluid from thereservoir230, afluid passage mechanism270 for receiving the fluid from thereservoir230 and passing the fluid to a destination, and acircuit board290 with control circuitry for controlling the device. Thefluid delivery device200 may include achassis100 that provides mechanical and/or electrical connections between components of the fluid deliverdevice200. One example of thechassis100 is disclosed in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and incorporated herein by reference. Thefluid delivery device200 may also include ahousing202 to enclose thecomponents210,230,250,270,290 and thechassis100.
• One embodiment of thereservoir230 includes anoutlet port232 for allowing fluid to exit thereservoir230. Thereservoir230 may also include aninlet port234 for allowing thereservoir230 to be filled with fluid. One embodiment of thereservoir230 is disclosed in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and has been incorporated by reference.
• One embodiment of thefluid passage mechanism270 includes atranscutaneous access tool272, such as a needle and/or soft cannula, which is capable of penetrating the skin of a patient and passing the fluid into the patient. A fluid path such as tubing (not shown) may be used to fluidly couple thereservoir230 to thetranscutaneous access tool272. Theaccess tool272 is mounted to an insertion mechanism, which may include slidingcarriages274,275, one ormore springs276, and a release member280 (seeFIG. 9). The slidingcarriages274,275 may be held in a first retracted position until therelease member280 causes the slidingcarriages274,275 to be released and the spring(s)276 drive the slidingcarriages274,275 in the direction of the arrow into an insertion position. Thedrive mechanism250 may be used to trigger therelease member280 by engaging an arm282 of therelease member280. In one embodiment, the slidingcarriages274,275 first insert a needle and a soft cannula and then the slidingcarriage275 withdraws the needle leaving the soft cannula in place. Various transcutaneous access devices and systems that may be accommodated in a chassis in accordance with the present invention are disclosed in, for example, U.S. Pat. No. 6,656,159 and U.S. patent application Ser. Nos. 10/128,206,10/195,745, 10/260,192,10/261,003, all of which are hereby incorporated by reference.
• Referring toFIGS. 2 and 3, one embodiment of thefluid driving mechanism250 includes a threadeddrive rod252 coupled to aplunger236. Theplunger236 is received in the fluid reservoir230 (seeFIG. 10). In the illustrated embodiment, thedrive wheel256 threadably engages and imparts linear motion to the threadeddrive rod252 to advance theplunger236 into thereservoir230, thereby forcing fluid out of thereservoir230. Alternatively, the threadeddrive rod252 may threadably engage theplunger236 and thedrive wheel256 may be fixed to thedrive rod252 to rotate thedrive rod252, which imparts linear motion to theplunger236.
• One embodiment of thedrive wheel256 includes first and secondratchet wheel portions258a,258band ahub254 between theratchet wheel portions258a,258b. Thedrive wheel256 may be rotatably supported by thechassis100. In particular, thehub254 may be supported by one or more bearing surfaces158a-con the chassis100 (seeFIG. 9). Thedrive wheel256 is preferably be made of plastic and thedrive rod252 is preferably made of metal or plastic.
• An actuation mechanism is used to engage and incrementally rotate thedrive wheel256. One embodiment of an actuating mechanism for thedrive wheel256 may include a linear actuator. A preferred linear actuator comprises a shape memory allow wire. As shown inFIGS. 2 and 3, preferably, the SMA wire comprises first and second shape memory alloy (SMA)wire portions260a,260bcoupled to a pivotabledrive engaging member262. The SMA wire portions260a,260bmay be formed as a continuous SMA wire crimped to the pivotabledrive engaging member262 as shown. The SMA wire portions260a,260bmay also be formed as separate pieces of wire connected to the pivotabledrive engaging member262 and may be connected in other ways known to those skilled in the art. The SMA wire may be made of nitinol, a well known alloy of nickel and titanium, or other SMA wire known to those skilled in the art. The pivotabledrive engaging member262 may be made of an electrically conductive material such as copper alloy.
• As shown inFIG. 4, theSMA wire portions260a,260bmay be mechanically secured to thechassis100 and electrically connected to contact points160a,160bon thechassis100. In the illustrated embodiment, theSMA wire portions260a,260bare connected to crimpterminations266a,266bwhich are mounted in slots formed in an electrically conductive portion of thechassis100. The crimp terminations266a,266bmay be made of a conductive material such as copper alloy. TheSMA wire portions260a,260bmay also wrap around posts161a,161bor other mechanical structures, for example, extending from thechassis100 to increase the functional length of the SMA wire.
• The pivotabledrive engaging member262 may be pivotably coupled to apivot point162 on thechassis100, which also acts as an electrical contact point. One embodiment of the pivotabledrive engaging member262 includesarms264a,264bthat engage teeth on theratchet wheel portions258a,258band incrementally rotating thedrive wheel256 when the pivotabledrive engaging member262 pivots. The pivotabledrive engaging member262 may also includelegs268a,268bthat contact points164a,164bon thechassis100 when the pivotabledrive engaging member262 pivots. Alternatively, the pivotabledrive engaging member262 may only include one arm and one leg.
• The contact points160a,160b,162,164a,164bprovide an electrical connection between the components of the actuating mechanism and the control circuitry (not shown). In one embodiment, this electrical connection is provided via conductive paths extending along thechassis100. The contact points160a,160belectrically connect theSMA wire portions260a,260bto actuatorconductive paths194a,194bon thechassis100. Thepivot point162 electrically connects the pivotabledrive engaging member262 to a common groundconductive path195 on thechassis100. The contact points164a,164belectrically connect the pivotabledrive engaging member262 to actuatorconductive paths196a,196b. The conductive paths along thechassis100 are shown and described in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and has been incorporated by reference. Those skilled in the art will recognize other means for electrically connecting the components of the actuating mechanism to the control circuitry.
• Referring toFIG. 5, the operation of the actuation mechanism is described in greater detail. To charge theSMA wire portions260a,260b, control circuitry (not shown) electrically connected to thechassis100 may selectively apply current to theSMA wire portions260a,260b, for example, via theconductive paths194a,194b(shown inFIG. 4). Current applied to a first SMA wire portion260apasses through the SMA wire portion260aand through the pivotabledrive engaging member262 to the common groundconductive path195 via the pivot point162 (shown inFIG. 4), thereby energizing the first SMA wire portion260awithout energizing the secondSMA wire portion260b. When charged, the first SMA wire portion260acontracts and pulls the pivotabledrive engaging member262 in a first direction indicated byarrow20. When the pivotabledrive engaging member262 pivots in thefirst direction20, the arm264aengages a tooth on theratchet wheel portion258acausing thedrive wheel256 to rotate one increment. The pivotabledrive engaging member262 pivots in thefirst direction20 until theleg268bcontacts the contact point164b, electrically connecting the pivotabledrive engaging member262 to the conductive path196b(shown inFIG. 4). This activates a signal to the control circuitry (not shown) via the conductive path196bindicating that the control circuitry should disable the current being applied to the first SMA wire portion260a. At all times one of thearms264aor264bis engaged by the tooth portions of the drive wheel. The engagedarm264aor264b, therefore prevents reverse rotation of the drive eliminating the need for a separate pawl element. As shown inFIG. 13, the teeth of thewheel portions258aand258bare offset relative to one another thereby maximizing the tolerances for the interface between thearms264aand264bandwheels258aand258b.
• To initiate another pulse, the control circuitry applies current to the secondSMA wire portion260b, for example, via the conductive path194band the contact point160b(shown inFIG. 4). When charged, the secondSMA wire portion260bcontracts and pulls the pivotabledrive engaging member262 in a second direction indicated byarrow22. When the pivotabledrive engaging member262 pivots in thesecond direction22, thearm264bengages a tooth on the ratchet wheel portion258bcausing thedrive wheel256 to rotate one increment. The pivotabledrive engaging member262 pivots in thesecond direction22 until the leg268acontacts the contact point164a, electrically connecting the pivotabledrive engaging member262 to theconductive path196a(shown inFIG. 4). This activates a signal to the control circuitry (not shown) via theconductive path196aindicating that the control circuitry should disable the current being applied to the secondSMA wire portion260b.
• Each incremental rotation of thedrive wheel256 advances the plunger in thereservoir230 to cause a discrete amount of fluid to be dispensed. The discrete amount of fluid to be dispensed is a function of the lead screw pitch (i.e., threads/inch), the number of teeth on the ratchet wheel (that is, ratchet wheel tooth size) and the diameter of the fluid reservoir. In a preferred embodiment, for delivering U100 insulin for treatment of Type I diabetes, the discrete amount of fluid to be dispensed is between about 0.25 μL and about 0.5 μL. The control circuitry alternates energizing theSMA wire portions260a,260buntil a desired amount of fluid has been dispensed. One example of the control circuitry and control method is disclosed in greater detail in U.S. patent application Ser. Nos. 10/835727, 10/836525, and 10/836535, which are fully incorporated herein by reference.
• Examples of alternative fluid driving mechanisms and actuation mechanisms that may be used in thefluid delivery device200 are disclosed in U.S. Pat. Nos. 6,656,158 and 6,656,159 and U.S. patent application Ser. No. 10/704,291, all of which are incorporated herein by reference.
• Thefluid delivery device200 may also include one or more sensors to monitor operation of thefluid driving mechanism250. For example, fill sensors may be used to sense a level of fluid in thereservoir230 when filling thereservoir230 with fluid and/or dispensing fluid from thereservoir230. Rotational sensors may be used to sense that thedriving mechanism250 is operating in accordance with expectations.
• Referring toFIGS. 6, 7A and7B, one embodiment of a fill sensor includes asensor bar292 supported or mounted at one end by asensor support166 and extending across the path of the threadeddrive rod252. When the threadeddrive rod252 engages thefill sensor bar292, thedrive rod252 moves thefill sensor bar292 and causes it to engage acontact point165. Engaging thecontact point165 completes a circuit and activates a fill sensor signal to the control circuitry. Thefill sensor bar292 may be made of an electrically conductive material such as a copper alloy and/or may be plated with a conductive material such as nickel or gold.
• At the point when thedrive rod252 causes thefill sensor bar292 to engage thecontact point165, theplunger236 is at a predetermined location in thereservoir230 and the amount of fluid in thereservoir230 is known. The fill sensor may be used when filling thefluid delivery device200 to indicate that the reservoir has been filled to a predetermined amount and/or to “wake up” the control circuitry in thefluid delivery device200. Thus, in a preferred embodiment of the present invention, before the fill sensor has been triggered, the fluid delivery device control circuitry is in a rest state characterized by minimal activity and power consumption. In such an embodiment, once the fill sensor is triggered, the control circuitry enters an active state characterized by higher activity and power consumption. The fill sensor may also be used when delivering the fluid to indicate that the predetermined amount of fluid remains in the reservoir. Although one embodiment of a fill sensor is shown and described, other configurations may be used to activate a fill sensor signal in response to a predetermined position of the drive rod. Referring toFIG. 14, in an alternative embodiment, the fill sensing system comprises a plurality ofsensor bars292 andcontact points165 placed at desired positions along thedrive rod252. The number and position of sensor bars and contact points may be selected for any desired resolution.
• Referring toFIGS. 8A and 8B, one embodiment of a rotational sensor includes arotational sensor bar294 supported or mounted at one end by asensor support168 and extending across a polygonal (or other camming) shaped portion of thedrive wheel256. Therotational sensor bar294 contacts asensor contact point169 to complete a circuit and activate a rotational sensor signal to the control circuitry. When thedrive wheel256 incrementally rotates, thehub254 of thedrive wheel256 engages therotational sensor bar294 and moves therotational sensor bar294 out of contact with thecontact point169. The activation and deactivation of the rotational sensor signal indicates that thedrive wheel256 is rotating. The specific shape of the polygonal portion of the drive wheel may be selected to optimize the resolution of the rotational sensor for a given application. In an alternative embodiment, as shown inFIGS. 15A, 15B and15C, a rotational sensor may comprise a sensor bar positioned to alternate between twocontact points169aand169b, thereby having 3 different states as shown inFIGS. 15A, 15B and15C, respectively, and a corresponding increase in resolution. Although one embodiment of a rotational sensor is shown and described, other configurations may be used to activate a rotational sensor signal in response to movement of the drive wheel.
• As shown inFIGS. 9 and 10, the sensor bars292,294 may be supported or mounted in thechassis100. In this embodiment, the sensor supports166,168 are electrically connected to the common groundconductive path195 extending along thechassis100 and the contact points165,169 are electrically connected to sensorconductive paths197,198, respectively, extending along thechassis100. The sensorconductive paths197,198 may be electrically connected to the control circuitry.
• Referring toFIGS. 11A and 11B, thedrive wheel256 may include athread engaging mechanism240 that moves from a non-thread-engaging position to a thread engaging position. The non-thread-engaging position allows the threadeddrive rod252 to pass freely through thedrive wheel256, for example, when the reservoir of the fluid delivery device is being filled. The thread engaging position allows the threadeddrive rod252 to be advanced when thedrive wheel256 is rotated, for example, when dispensing or delivering fluid from the reservoir.
• One embodiment of thethread engaging mechanism240 includes atilt nut242 having threadedregions244a,244b. Thetilt nut242 may include one or more pivot pins246 that pivotably support thetilt nut242 within the drive wheel256 (seeFIG. 2). The tilt nut pins246 provide a pivot axis for thetilt nut242 that is perpendicular to that of thedrive rod252. The pivot axis is preferably offset from the center of thetilt nut242. Thetilt nut242 is retained in thedrive wheel256 by portions of the chassis and by thetilt nut clip1201, which is shown exploded inFIG. 12A. When thetilt nut242 is in the open (tilted) position, the threadedregions244a,244bdo not engage the threads on the threaded drive rod252 (FIG. 11A). When thetilt nut242 is in the closed position (FIG. 11B) the threaded portions engage the threadeddrive rod252.
• According to one embodiment, shown inFIGS. 12A and 12B, thetilt nut242 may also include acam member248 that engagesguide surface146 andcamming surface148 on thechassis100. Initially, thecam member248 engages theguide surface146 and is maintained in the open (tilted) position (FIG. 12A). During initial rotation, thecam member248 engages thecamming surface148 and thecamming surface148 forces thecam member248 to pivot into the thread engaging position. Thetilt nut242 may remain in the thread engaging position as thedrive wheel256 rotates to advance thedrive rod252 and theplunger236, thereby dispensing fluid. Once thedrive rod252 is engaged by thetilt nut252, the tilt nut is retained in the closed position by the surfaces of the chassis and the tilt nut clip and by the pressure of the drive rod against the offset pivot axis of thetilt nut242 in the direction of theplunger236. Notably, in a preferred embodiment, the stiction of the O-rings501 on theplunger236 provides sufficient anti-rotational friction to prevent the plunger from rotating with thedrive rod252.
• FIGS. 16 and 17 show an alternative embodiment of a “wake-up” system for a fluid delivery device.FIG. 16 shows the bottom surface of a fluid delivery device having atranscutaneous access tool270 and aneedle cap1601. As shown inFIG. 17, the needle cap is electrically and/or mechanically connected to aswitch1705 that couples apower source1703 and thecontrol circuitry1705. Removal of thecap1601 closes the switch between thepower source1703 and thecontrol circuitry1705 thereby “waking” the fluid delivery device.
• Although the illustrated embodiment shows the components mechanically secured to and electrically connected to a single chassis, the components of the fluid delivery device consistent with embodiments of the present invention may be mechanically secured and/or electrically connected to other structures such as separate structural members or the housing.
• In summary, a fluid delivery device, consistent with one embodiment of the present invention, includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, and a drive wheel coupled to the threaded drive rod. The fluid delivery device also includes a pivotable drive engaging member including at least one arm configured to engage and incrementally rotate the drive wheel and at least first and second shape memory alloy (SMA) wire portions coupled to the pivotable drive engaging member to pivot the pivotable drive engaging member. In response to being charged, the first SMA wire portion is configured to contract and pull the pivotable drive engaging member in a first direction and the second SMA wire portion is configured to contract and pull the pivotable drive engaging member in a second direction.
• Consistent with another embodiment of the present invention, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, a drive wheel coupled to the threaded drive rod, and an actuating mechanism configured to engage and incrementally rotate the drive wheel. This embodiment of the fluid delivery device also includes a rotational sensor extending across the drive wheel. The drive wheel is configured to engage the rotational sensor during rotation to cause the rotational sensor to contact a conductive path activating an electrical signal indicating rotation of the drive wheel.
• Consistent with a further embodiment of the present invention, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, a drive wheel configured to threadably engage the threaded drive rod to impart linear motion to the threaded drive rod when the drive wheel rotates, and an actuating mechanism configured to engage and incrementally rotate the drive wheel. This embodiment of the fluid delivery device also includes a fill sensor extending across a path of the threaded drive rod. The threaded drive rod is configured to engage the fill sensor when the plunger is at a predetermined location in the fluid reservoir to cause the fill sensor to contact an electrically conductive path enabling an electrical signal indicating an amount of fluid in the fluid reservoir.
• Consistent with yet another embodiment, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, and a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir. In this embodiment, the fluid delivery device also includes a drive wheel configured to receive the threaded drive rod and including a thread engaging mechanism configured to move from a non-thread-engaging position to a thread engaging position in which the thread engaging mechanism engages threads of the threaded drive rod. The drive wheel is configured to impart linear motion to the threaded drive rod when the thread engaging mechanism is in the thread engaging position and the drive wheel rotates.
• While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.

Claims (27)

1. A fluid delivery device comprising:

a fluid reservoir;

a plunger received in said fluid reservoir;

a threaded drive rod coupled to said plunger to advance said plunger in said fluid reservoir;

a drive wheel coupled to said threaded drive rod;

a pivotable drive engaging member including at least one arm configured to engage and incrementally rotate said drive wheel; and

a linear actuator coupled to said pivotable drive engaging member to pivot said pivotable drive engaging member, wherein said linear actuator causes the pivotable drive engaging member to pivot when actuated.

2. The fluid delivery device ofclaim 1, wherein the linear actuator is a SMA wire.

3. The fluid delivery device ofclaim 2, wherein the SMA wire comprises at least first and second SMA wire portions wherein activation of the first SMA wire portion causes the pivotable drive engaging member to pivot in a first direction and wherein activation of the second SMA wire portion causes the pivotable drive engaging member to pivot in a second direction.

4. The fluid delivery device ofclaim 3 wherein said first and second SMA wire portions are part of a continuous SMA wire having first and second ends, wherein said pivotable drive engaging member is coupled between said first and second ends.

5. The fluid delivery device ofclaim 1 wherein said pivotable drive engaging member includes at least one leg configured to contact an electrically conductive path to activate an actuator signal.

6. The fluid delivery device ofclaim 5 wherein said pivotable drive engaging member includes:

first and second arms configured to engage and incrementally rotate said drive wheel as said drive engaging member pivots in respective said first and second directions.

7. The device ofclaim 6, wherein the pivotable drive engaging member comprises first and second legs configured to contact electrically conductive paths to activate actuator signals as said drive engaging member pivots in respective said first and second directions.

8. The fluid delivery device ofclaim 6 wherein said drive wheel includes first and second ratchet wheel portions configured to be engaged by said first and second arms of said pivotable drive engaging member.

9. The fluid delivery device ofclaim 6, wherein the first and second ratchet wheel portions comprise a plurality of teeth for engaging the arms of the pivotable drive engaging member and wherein the teeth of the first ratchet wheel are offset relative to the teeth of the second ratchet wheel.

10. The fluid delivery device ofclaim 3 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, said pivotable drive engaging member and said SMA wire portions.

11. The fluid delivery device ofclaim 10 wherein said pivotable drive engaging member is pivotably coupled to said chassis, and wherein said SMA wire is mounted to said chassis at said first and second ends.

12. The fluid delivery device ofclaim 11 wherein said chassis includes electrically conductive paths, wherein said first and second SMA wire portions are electrically connected to two of said conductive paths configured to conduct electrical current to said SMA wire portions, and wherein said pivotable drive engaging member is electrically connected to another one of said conductive paths configured to act as a common ground.

13. The fluid delivery device ofclaim 1 further comprising a rotational sensor extending across said drive wheel, said drive wheel being configured to engage said rotational sensor during at least a portion of rotation of said drive wheel to cause said rotational sensor to engage and disengage an electrically conductive path thereby activating a rotational sensor signal indicating rotation of said drive wheel.

14. The fluid delivery device ofclaim 13 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, said pivotable drive engaging member and said SMA wire portions, wherein said chassis includes electrically conductive paths, wherein one end of said rotational sensor is mounted to said chassis and electrically connected to one of said conductive paths, and wherein said rotational sensor is configured to move into and out of contact with another of said electrically conductive paths to activate said rotational sensor signal.

15. The fluid delivery device ofclaim 1 wherein said drive wheel is configured to threadably engage said threaded drive rod to impart linear motion to said threaded drive rod.

16. The fluid delivery device ofclaim 15 further comprising a fill sensor extending across a path of said threaded drive rod, said threaded drive rod being configured to engage said fill sensor when said plunger is at a predetermined location in said fluid reservoir to cause said fill sensor to contact a conductive path activating a fill sensor signal indicating an amount of fluid in said fluid reservoir.

17. The fluid delivery device ofclaim 16 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, said pivotable drive engaging member and said SMA wire portions, wherein said chassis includes electrically conductive paths, wherein one end of said fill sensor is mounted to said chassis and electrically connected to one of said conductive paths, and wherein said fill sensor is configured to move into contact another of said conductive paths to activate said fill sensor signal.

18. The fluid delivery device ofclaim 15 comprising a plurality of fill sensors extending across a path of said threaded drive rod, said threaded drive rod being configured to engage said fill sensors when said plunger is at predetermined locations in said fluid reservoir to cause said fill sensors to contact a conductive path activating fill sensor signals, each indicating an amount of fluid in said fluid reservoir.

19. The fluid delivery device ofclaim 1 wherein said drive wheel includes a thread engaging mechanism configured to move from a non-thread-engaging position to a thread engaging position in which said thread engaging mechanism engages threads of said threaded drive rod, said drive wheel being configured to impart linear motion to said threaded drive rod when said thread engaging mechanism is in said thread engaging position and said drive wheel rotates.

20. A fluid delivery device comprising:

a fluid reservoir;

a plunger received in said fluid reservoir;

a threaded drive rod coupled to said plunger to advance said plunger in said fluid reservoir;

a drive wheel coupled to said threaded drive rod;

an actuating mechanism configured to engage and incrementally rotate said drive wheel; and

a rotational sensor extending across said drive wheel, said drive wheel being configured to engage said rotational sensor during rotation to cause said rotational sensor to contact a conductive path activating an electrical signal indicating rotation of said drive wheel.

21. The fluid delivery device ofclaim 20 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, and said actuating mechanism, wherein said chassis includes electrically conductive paths, wherein one end of said rotational sensor is mounted to said chassis and electrically connected to one of said conductive paths, and wherein said rotational sensor is configured to move into and out of contact with another of said electrically conductive paths to activate said electrical signal.

22. The fluid delivery device ofclaim 20 wherein said drive wheel includes a hub configured to contact said rotational sensor.

23. A fluid delivery device comprising:

a fluid reservoir;

a plunger received in said fluid reservoir;

a threaded drive rod coupled to said plunger to advance said plunger in said fluid reservoir;

a drive wheel configured to threadably engage said threaded drive rod, said drive wheel

being configured to impart linear motion to said threaded drive rod when said drive wheel rotates;

an actuating mechanism configured to engage and incrementally rotate said drive wheel; and

a fill sensor extending across a path of said threaded drive rod, said threaded drive rod being configured to engage said fill sensor when said plunger is at a predetermined location in said fluid reservoir to cause said fill sensor to contact an electrically conductive path enabling an electrical signal indicating an amount of fluid in said fluid reservoir.

24. The fluid delivery device ofclaim 23 comprising a plurality of fill sensors extending across a path of said threaded drive rod, said threaded drive rod being configured to engage said fill sensors when said plunger is at predetermined locations in said fluid reservoir to cause said fill sensors to contact a conductive path activating fill sensor signals, each indicating an amount of fluid in said fluid reservoir.

25. The fluid delivery device ofclaim 23 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, and said actuating mechanism, wherein said chassis includes electrically conductive paths, wherein one end of said fill sensor is mounted to said chassis and electrically connected to one of said conductive paths, and wherein said fill sensor is configured to move into contact with another of said electrically conductive paths to activate said electrical signal.

26. A fluid delivery device comprising:

a fluid reservoir;

a plunger received in said fluid reservoir;

a threaded drive rod coupled to said plunger to advance said plunger in said fluid reservoir;

a drive wheel configured to receive said threaded drive rod, said drive wheel including a thread engaging mechanism configured to move from a non-thread-engaging position to a thread engaging position in which said thread engaging mechanism engages threads of said threaded drive rod, said drive wheel being configured to impart linear motion to said threaded drive rod when said thread engaging mechanism is in said thread engaging position and said drive wheel rotates; and

an actuating mechanism configured to engage and incrementally rotate said drive wheel.

27. The fluid delivery device ofclaim 26 further comprising a chassis mechanically interfacing said fluid reservoir, said drive wheel, and said actuating mechanism, wherein said chassis includes a camming surface configured to engage said thread engaging mechanism to move said thread engaging mechanism from said non-thread-engaging position to said thread engaging position.

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