Patent Application
20250205415
The present invention generally relates to systems and methods for coupling a disposable part (“DP”) (e.g., liquid drug container(s)/reservoir(s)) of a drug delivery device (pump device) to a reusable part (“RP”) of the pump device. More specifically, the present invention relates to magnetic coupling mechanisms for magnetically releasably coupling (releasably attaching/engaging) a DP to a RP of a drug delivery device, and to magnetic-field based detection methods for detecting engagement (coupling/attachment) and disengagement (decoupling), and optionally engagement orientation, between the DP and the RP of the drug delivery device.
Some liquid drug delivery systems are two-part systems including a RP, which typically includes, among other things, an electric motor and a gear system that is driven by the electric motor, and a DP that typically includes liquid drug reservoir(s) and a gear-driven plunger rod to expel drug out of the reservoir(s). NeuroDerm Ltd. (a company based in Israel), for example, has developed a proprietary small two-part wearable infusion drug delivery device to deliver liquid drug to Parkinson disease (PD) patients subcutaneously.
Ability to detect, by a controller of the pump device, in conjunction with a sensor system, when the DP and the RP are properly engaged has benefits, for example in terms of safety of operation of the liquid drug delivery system, ensuring accurate drug dosing and avoiding various mechanical issues that may result from mechanical wear (that may change mechanical tolerances,) or damage. For example, engaging a DP of a pump device with a RP of the pump device should be a prerequisite to safe operation of the pump device.
Some pump devices use a magnetic field source and a magnetic field sensor to sense when the DP and the RP of the pump device are properly engaged. Typically to these devices, the DP includes a magnet as a magnetic field source, and the RP includes a magnetic field sensor. Using this kind of ‘magnet-sensor’ configuration, the magnetic field that is sensed by the magnetic field sensor is maximal when the DP and the RP are engaged, and, conversely, the magnetic field that is sensed by the magnetic field sensor is minimal when the DP and the RP are pulled away from one another. So, a decision regarding the state of engagement of the DP and the RP is made (e.g., by a controller) accordingly. Incorporating a magnet into the DP is wasteful because each DP requires a magnet, and, in addition, all magnets would have to be magnetized in exactly the same way in order to ensure that all pump devices perform in the same way.
Typically, a DP of a pump device that includes a magnet and a RP of the pump device that includes a magnetic field sensor are attached by using a mechanical coupling device or connector, for example a snap-fit mechanism (e.g., cantilever snap-fit), mating threaded elements or a bayonet connector. It would be beneficial to have a pump device where a magnet may be used for simultaneously releasably coupling the DP to the RP of the pump device and sensing when the DP and RP of the pump device are engaged and disengaged. In addition, it would be beneficial to have a pump device that improves usability (case of use) for patients suffering from motor impairment, in particular patients who are unable to operate a mechanism that requires movement precision and accuracy, or physical strength, or both movement precision/accuracy and physical strength, as is often the case with PD patients.
A bifunctional magnetic mechanism generates a magnetic attraction force to magnetically engage a disposable and reusable parts of a pump device, and, at the same time, the bifunctional magnetic mechanism uses the same magnetic field to detect an engagement state between the two parts of the pump device. The bifunctional magnetic mechanism includes a permanent magnet to produce magnetic field(s) that zero out a net magnetic field at a sensor, an asymmetrical metal plate (AMP) to magnetically disrupt (deflect, redirect) the magnetic field(s) at the sensor, and a magnetic field sensor to sense the magnetic disruption/deflection. The magnet and the sensor are incorporated in the RP of the pump device such that the magnetic field sensor is circumferentially surrounded by the magnet. The AMP is incorporated in the DP such that the AMP subtends the sensor (i.e., is adjacent to the sensor in functionally optimized manner) when the DP and RP are engaged. (The design (geometry and relative position) of the two parts (AMP and magnet/sensor, including the other parts supporting them) ensures that the AMP is centered in front of the magnet/sensor in an optimal manner to ensure optimal operation of the mechanism that is disclosed herein.
The pump device for delivering fluid medicament(s) to a user includes a RP and a DP for engagement with the RP. The RP includes, among other things, a magnetic field sensor having a magnetic field sensing area, a magnet that is circumferentially surrounding the magnetic field sensor and magnetized to produce one or more magnetic fields in direction(s) that zero out a net magnetic field that is sensed by the magnetic field sensor, and a controller to read an output value of the magnetic field sensor. The DP is magnetically engageable with the RP and includes a metal plate that is magnetically attractable to the magnet to magnetically engage the DP with the RP, and, during the engagement, to magnetically deflect one or more of the one or more magnetic fields at the magnetic field sensing area such that the net magnetic field sensed by the magnetic field sensor is greater than zero. The controller is configured to determine an engagement state between the DP and the RP from an output value (Sa) of the magnetic field sensor that corresponds to the sensed net magnetic field.
Each of the magnetic field sensing area, the magnet and the metal plate form a plane that coincides with, or is parallel to, an X-Z plane of the Cartesian coordinate system and perpendicular to the Y-axis of the Cartesian coordinate system. The magnet includes a central aperture, and the magnetic field sensor is centered in the aperture of the magnet at a point that coincides with the origin of the Cartesian coordinate system. The metal plate is asymmetrical with respect to an asymmetry line coinciding with the Z-axis, and the asymmetry line divides the metal plate into a primary section and an auxiliary section.
The primary section of the asymmetrical metal plate (AMP) is configured to induce a magnetic attraction force between the primary section and the magnet when the DP is brought into proximity to the RP, and, at the same time, to deflect the one or more of the one or more magnetic fields at or near the sensor's sensing area. The auxiliary section of the AMP is configured to induce a magnetic attraction force between the auxiliary section and the magnet when the DP is brought into proximity to the RP. The metal plate unevenly deflects the one or more of the one or more magnetic fields to make the deflection detectable by the controller. The metal plate may be configured such that the magnetic field sensor does not enter saturation when the DP is engaged with the RP in order to enable the controller to distinguish between the engagement state of the DP and RP, and a faulty condition that results in the magnetic field sensor entering saturation.
The DP may include one medicament reservoir, and the controller may compare the output value (Sa) of the magnetic field sensor to a threshold value (Sth) to determine the engagement state of the DP and RP. The controller may check the value of Sa once every t1 seconds when the disposable and reusable parts of the pump device are engaged or the pump device actually delivers medicament to a patient, and once every t2 seconds (where t2>t1) when the disposable and reusable parts of the pump device are disengaged or the pump device does not deliver medicament to the patient. The value of t1 may be, for example, 0.01 second, 0.5 second, 1.0 second, etc., and the value of t2 may be, for example, 3.0 seconds, 5.0 seconds, 10.0 seconds, etc.
The DP may include two medicament reservoirs, and the controller may compare the output value (Sa) of the magnetic field sensor to a null value (Snull) of the magnetic field sensor to distinguish between engagement of the DP and the RP in a first engagement orientation (‘SIDE-B’) and engagement of the DP and RP in a second engagement orientation (‘SIDE-A’). The controller may compare the output value (Sa) of the magnetic field sensor to a first threshold value (Sth1) to determine engagement of the DP in the first engagement orientation (‘SIDE-B’), and to a second threshold value (Sth2) to determine engagement in the second engagement orientation (‘SIDE-A’), where Sth1>Snull>Sth2. The first engagement orientation (‘SIDE-B’) of the DP is distinguishable from the second engagement orientation (‘SIDE-A’) of the DP due to (thanks to) the asymmetry of the metal plate with respect to the asymmetry line that coincides with the Z-axis. The controller may output to a user of the pump device (e.g., a patient), audibly and/or visually, an indication regarding engagement between the DP and the RP and/or correctness of the engagement orientation.
The magnet may be a permanent magnet that is configured as a dipole magnet that is magnetized diametrically. The dipole magnet is configured to produce a magnetic field that is parallel to the magnetic field sensing area such that the net magnetic field that is sensed by the magnetic field sensor is zero, or near zero. During engagement of the DP with the RP the net magnetic field sensed by the magnetic field sensor is greater than zero because of the deflection of the magnetic field that the metal plate causes at the magnetic field sensing area.
The magnet may be a permanent magnet that is configured as a multipole magnet. The multipole magnet may include a number ‘n’ (n=1, 2, 3, . . . ) of pairs of conjugated magnetic poles (N/S), and may be magnetized diametrically, or axially, or both diametrically and axially. The multipole magnet is configured to produce multiple magnetic fields in opposite directions at the magnetic field sensing area such that the net magnetic field sensed by the magnetic field sensor is zero, or near zero, due to mutual cancellation of opposing magnetic fields at the magnetic field sensing area. The multipole magnet may be a 4-pole magnet. The 4-pole magnet may include a first pair of conjugate magnetic poles (N/S) that is axially magnetized in a first direction, and a second pair of conjugate magnetic poles (S/N) that is axially magnetized in a second direction opposite the first direction. During engagement of the DP with the RP the magnetic field sensed by the magnetic field sensor is greater than zero due to the metal plate deflecting the magnetic fields at the magnetic field sensing area.
In some embodiments the primary section and the auxiliary section of the asymmetrical metal plate (AMP) are separate, unconnected, sections. In other embodiments the primary section and the auxiliary section of the asymmetrical metal plate (AMP) form one monolithic object.
In some embodiments the primary section of the asymmetrical metal plate (AMP) includes a primary tab that extends inwardly in the AMP, towards the auxiliary section of the AMP. In some embodiments the auxiliary section of the AMP may also include a tab (an auxiliary tab) that extends inwardly in the AMP, towards the primary tab. The primary tab extends inwardly more than the auxiliary tab, and has a greater surface area than the auxiliary tab.
The primary section of the AMP is configured to partially overlap the magnetic field sensing area when the DP and the RP are engaged, with the partial overlapping percentage being P[%]. The value of P[%] is a tradeoff between a magnetic attraction force to be induced between the magnet and the AMP and a magnetic deflection to be induce by the AMP in the magnetic field(s) at the magnetic field sensing area. The value of P[%] may be selected such that the magnetic field sensor does not enter saturation when the DP and the RP are engaged, to enable the controller to distinguish the engagement state from a faulty condition causing the magnetic field sensor to enter saturation. In some embodiments the value of P is 50%±10%. The design of the AMP may be a tradeoff between a magnetic attraction force to be induced between the magnet and the asymmetrical metal plate, and a magnetic deflection to be induce by the asymmetrical metal plate in the magnetic field(s) at the magnetic field sensing area.
Various exemplary embodiments and aspects are illustrated in the accompanying figures with the intent that these examples be not restrictive. It will be appreciated that for simplicity and clarity of the illustration, elements shown in the figures referenced below are not necessarily drawn to scale. Also, where considered appropriate, reference numerals may be repeated among the figures to indicate like, corresponding or analogous elements. Of the accompanying figures:
The description that follows provides various details of example embodiments. However, this description is not intended to limit the scope of the claims but instead to explain various principles of the invention and exemplary manners of practicing it.
The description that follows describes a bifunctional magnetic mechanism that is designed to generate a magnetic attraction force to attach a DP of a pump device to a RP of the pump device, and to simultaneously (at the same time) use the same magnetic field to detect engagement of the two parts (DP and RP) of the pump device. The bifunctional magnetic mechanism includes three main parts: (1) a permanent magnet that is configured (in terms of number of pairs of conjugated poles and magnetization) to produce a composite magnetic field from one or more magnetic fields that are orientated in desired direction(s), (2) an asymmetrical metal plate (AMP) that is configured to disrupt the composite magnetic field produced by the magnet, and (3) a magnetic field sensor to sense a level of disruption in the composite magnetic field. The magnet and the magnetic field sensor are incorporated into a RP of a pump device in a way that the magnetic field sensor is circumferentially surrounded by the magnet. The AMP, on the other hand, is incorporated into a DP of the pump device in a way that the AMP subtends the magnetic field sensor (i.e., adjacent to the sensor) when the DP and RP of the pump device are engaged. Disrupting magnetic field(s) by an AMP, which acts as a magnetic shunt, means deflecting (redirecting) some of the magnetic lines of force of the magnetic field(s) from their ‘natural’, or original, magnetic path.
The AMP is designed to simultaneously perform two types of magnetic interactions with the magnetic field(s) that are produced by the magnet: (1) the AMP is magnetically attractable to the magnet, so that it can magnetically attach the DP and RP of the pump device, and (2) the AMP is also designed to disrupt the magnetic field(s) (e.g., modify or redirect them) that is/are produced by the magnet in a way that would make the disrupted (modified, redirected) magnetic field(s) detectable by the magnetic field sensor. A key point in sensing magnetic field(s) by the magnetic field sensor is that when the two parts intended for attachment (e.g., DP and RP of a pump device) are disengaged (i.e., distanced away from one another), the net magnetic field that the magnetic field sensor senses is zero, or near zero. So, when the net magnetic field that the magnetic field sensor senses is zero, or near zero, a controller, by ‘reading’ the sensor's output, can determine that the DP and RP of the pump device are not engaged. On the other hand, if the DP and the RP of the pump device are engaged, the disruption caused by the AMP in the magnetic field at, or near, the magnetic field sensor causes the net magnetic field that is sensed by the magnetic field sensor to increase, which facilitates detection of the engagement and disengagement of the two parts (DP, RP) of the pump.
When the DP and the RP are disengaged, the net magnetic field that the sensor senses is zeroed out (or minimized) by one or more magnetic fields that are produced by the magnet in specific direction(s) relative to the sensor's sensing plane (sensing area) of the magnetic field sensor. Producing magnetic field(s) in the required direction(s) by the magnet is obtained by redirecting the magnetic field lines through manipulation of the magnetization scheme of the magnet. Sintered neodymium iron boron magnet (NdFeB) can be multi-pole magnetized according to the needs, i.e., multiple ‘N’ (north) poles and ‘S’ (south) poles can be formed, for example, on one plane after magnetization.
Magnetic shielding generally means surrounding an object (for example a magnetic field sensor) with a magnetically conducting material that can “conduct” magnetic flux better than the materials around it. Using a magnetically conducting material the magnetic field lines tend to ‘flow’ (i.e., to be redirected) along this material and, thus, avoid the object inside. Using a magnetic shield allows the magnetic field lines to terminate on the opposite poles while giving them a different route to follow. Magnetic flux lines follow a path of least magnetic resistance, which is characterized by having a relatively high magnetic permeability, μ (e.g., μ>1.0, where μ=1.0 is the permeability of air). Therefore, if a material with a high magnetic permeability is nearby a magnet, the magnetic flux lines travel the path of least magnetic resistance (through the higher permeability material), leaving less magnetic field in the surrounding air. (‘Magnetic permeability’ is a scalar quantity quantifying a material's resistance to the magnetic field, or the degree to which magnetic field can penetrate and pass through the material.) A material endowed with highly permeable properties has high magnetic susceptibility to an applied magnetic field; and it readily accepts the flow of magnetic field through it.
As described herein (for example in connection with
Magnet 110 circumferentially surrounds magnetic field sensor 120 and is magnetized to produce one or more magnetic fields in particular direction(s) to zero-out a net magnetic field that is sensed by magnetic field sensor 120 when AMP 130 and sensor 120 are distanced away from one another.
Asymmetrical metal plate (AMP) 130 is configured to be magnetically attracted to magnet 110 when AMP 130 and magnet 110 are positioned adjacent to each other, and, in addition, to disrupt (e.g., deflect) the one or more magnetic fields at the magnetic field sensing area 124 when AMP 130 is adjacent to magnetic field sensing area 124 (e.g., at detection distance 140 from magnetic field sensing area 124, or closer), to thereby increase the net magnetic field that is sensed by magnetic field sensor 120.
Dipole magnet 210 is a ring-shaped magnet including a North (‘N’) pole and a South (‘S’) pole opposite the N pole. Using this MMS layout/configuration, the direction of magnetic field 220, if undisrupted, is parallel to the sensor's sensing area/plane 232 of magnetic field sensor 230, meaning that the angle between the sensor's magnetic sensing area and the magnetic field lines is zero degrees. Therefore, the net magnetic field that magnetic field sensor 230 senses is zero. However, when an AMP (example AMPs are shown, for example, in
Like in
The two magnetic fields that the two, adjacent, magnets (340, 350) produce in the space between them (i.e., in the space shared by them) are relatively uniform and antiparallel (i.e., they are directed to opposite directions). This phenomenon is obtained by using pairs of N/S poles that produce magnetic fields in opposite directions. For example, axially magnetized magnet 340 includes a first pair of conjugated N/S poles that produces a magnetic field 342 in a first direction coinciding with ‘symmetry’ line 370, and axially magnetized magnet 350 includes a second pair of conjugated S/N poles that produces a magnetic field 352 in a second direction that also coincides with symmetry line 370. However, magnetic field 342 and magnetic field 352 are directed to opposite directions. (Magnetic field 342 and magnetic field 352 are antiparallel vector fields.) North pole 342 and south pole 344 make up a first pair of conjugated poles, and south pole 352 and north pole 354 make up a second pair of conjugated poles.
Axially magnetized magnets 340 and 350 are designed such that they produce magnetic fields with the same magnetic field strength at a same point, or area, in a space between the two magnets, and the two magnets direct the two magnetic fields to opposite directions at that point, or area, in order for them to cancel out each other at that point or area. The point (or area) where magnetic fields cancel out each other is called ‘neutral point’ (or ‘neutral area’). This kind of magnetic field cancellation occurs because magnetic fields obey the superposition principle, so two magnetic fields that are opposite in directions are subtracted, and if the two magnetic fields are equal in strength, subtracting them results in a zero magnetic field at that point or area. So, if magnetic fields 342 and 352 have equal magnitude, and given their opposite directions, the net magnetic field that magnetic field sensor 360 senses (detects) at the neutral point/area is zero.
Like in
An axially magnetized magnet (e.g., 4-pole magnet 410,
Referring to
Structurally, AMP 500 includes a first (primary) section 550 that is configured to disrupt (modify) the magnetic field(s) produced by the magnet (e.g., magnet 110, 250, or 410) when AMP 500 is at, or near, the magnet (hence at or near the magnetic field sensor that is surrounded by the magnet). The extent to which the magnetic field(s) produced by the magnet are disrupted (modified, distorted) by AMP 500 primarily depends on the size, shape and material of section 550. In general, the greater the area of first section 550, the greater the disruption to the magnetic field(s), hence the output signal of the magnetic field sensor 570 (
AMP 500 also includes a second (an auxiliary) section, that is section 560, that is designed to produce an additional magnetic attraction force to thereby increase the overall magnetic attraction force that is induced between the magnet and AMP 500. (Section 560 of AMP 500 plays a negligible role, if at all, in the disruption of the magnetic field(s).)
Second part 620 functions in a similar way as second (auxiliary) section 560 of
Part 610 includes a peripheral base 612 and a tab 630 that extends/protrudes (640) from peripheral base 612 inwardly, along the X-axis, towards auxiliary part 620. Tab 630 imparts asymmetry to AMP 600 with respect to the Z-axis. The size and shape of tab 630 may differ, or deviate, from those that are shown in
Section 720 of AMP 700 functions in a similar way as auxiliary part 620. Namely, section 720 is configured to produce an additional magnetic attraction force to increase the overall magnetic attraction force that is induced between the magnet and AMP 700. (Auxiliary section 720 of AMP 700 plays a negligible role, if at all, in the disruption of the magnetic field(s).)
Section 710 includes a peripheral basc 712 and a tab 730 (primary tab) that extends/protrudes (740) from peripheral base 712 inwardly, along the X-axis, towards auxiliary section 720. An air gap 750 exists between tab 730 and a peripheral base 722 of auxiliary section 720. Tab 730 imparts asymmetry to AMP 700 with respect to the Z-axis, with line 780 being the asymmetry line between section 710 and section 720. The size and shape of tab 730 may differ, or deviate, from those that are shown in
AMP 700 differs from AMP 600 of
AMP 800 differs from AMP 700 in that AMP 800 includes a second (an auxiliary) tab 860. Auxiliary tab 860 extends/protrudes (L2) inwardly, in the direction of the X-axis, from a peripheral base 822 of auxiliary section 820 towards first tab 830, leaving an air gap 870 between ‘primary’ tab 830 and ‘auxiliary’ tab 860. Protrusion length L1 of tab 830 of primary section 810 is greater than the protrusion length L2 of tab 860 of auxiliary section 810 (L1>L2).
Primary section 810 functions in a similar way as primary section 710 of
Auxiliary section 820 functions in a similar way as auxiliary part 720. Namely, auxiliary section 820 is configured to produce an additional magnetic attraction force to increase the overall magnetic attraction force that is induced between the magnet and AMP 800. (Auxiliary section 820 of AMP 800 plays a negligible role, if at all, in the disruption of the magnetic field(s).) Most of the additional magnetic attraction force that is provided by auxiliary section 820 is provided by tab 860.
The size (width and/or length) and shape of air gap 870 and its location along the X-axis are designed as, or embody, a tradeoff between the intended magnetic disruption that AMT 800 is to induce in the magnetic fields produced by the magnet (hence the resulting output dynamic range of the magnetic field sensor), and the magnetic attraction force that AMT 800 induces vis-à-vis the magnet.
The design of tabs 830 and 860 (including size and shape) imparts asymmetry to AMP 800 with respect to the Z-axis, with line 880 being the asymmetry line between section 810 and section 820. The size and shape of tabs 830 and 860 may differ, or deviate, from those that are shown in
In the description that follows ‘
The bridge connectors shown in
The assembly process of DP 1010 includes, among other things, attaching housing top cover 1000 (with AMP 500 seating therein) to DP 1010. In this example, DP 1010 includes two medicament reservoirs, one of which is accessible (operable) via luer connector 1020, and the other reservoir is accessible (operable) via luer connector 1030.
The AMP (e.g., AMP 500 in
Disposable part 1320 of pump device 1300 may generally include one or more medicament reservoirs. By way of example, DP 1320 includes two medicament reservoirs (reservoirs 1360 and 1370). Disposable part 1320 also includes an AMP 1380 to magnetically interact with the magnet-sensor combination at 1350 when RP 1310 and DP 1320 are engaged (1390). During engagement (1390), the distance (air gap) between AMP 1380 in the DP and the magnet-sensor combination at 1350 in the RP is getting shorter, leading to increased disruption in the magnetic field(s) that is/are sensed by the magnetic field sensor at 1350. Increasing the magnetic disruption by AMP 1380 has bearing on the value of the sensor's output in a way that enables the controller in RP 1310 to determine whether RP 1310 and DP 1320 are engaged or disengaged. During engagement of RP 1310 and DP 1320 a driving nut 1362 associated with reservoir 1360 is engaged with, and rotatable by, a driving gear at 1332 to linearly move a driving screw 1364, hence a plunger head in reservoir 1360. Similarly, a driving nut 1372 associated with reservoir 1360 is engaged with, and rotatable by, a drive gear at 1334 to linearly move a driving screw 1374, hence a plunger head in reservoir 1370.
AMP 1380 may resemble AMP 500, AMP 600, AMP 700, or AMP 800, or it may have a different design so long as the design of the AMP simultaneously complies with the two requirements described herein; namely, the AMP can cause a sensor-detectable magnetic disruption in the magnetic field(s) that is (are) produced by the magnet, and it can induce a sufficiently strong magnetic attraction force between the AMP and the magnet to secure engagement between the RP and DP of the pump device. Common to all AMP designs is the notion that the magnetic attraction force induced between the AMP and the magnet should not be too strong in order to enable a user, for example a PD subject, to effortlessly disengage the two parts.
In some embodiments, both reservoirs (e.g., reservoirs 1360 and 1370 of
So, as described herein, detecting only an engagement between a DP and a RP of a pump device may not suffice for normal operation of the pump device because, depending on the type of medicament in each reservoir and/or medicament regimen, the engagement orientation may also be of importance, hence needs to be checked for correctness. Therefore, the controller may be configured to use the sensor's output value to detect both states of the pump: (1) engagement state between the DP and RP of the pump device, and (2) correctness of the engagement orientation. The controller may be configured to output (audibly and/or visually) a corresponding indication to the patient, for example “engaged”, “disengaged”, “correct orientation”, “incorrect orientation”, etc. In terms of engagement detection, DP 1320 includes only a simple, relatively inexpensive, metal plate, which makes DP 1320 more readily disposable after use.
Magnet 1410 may be a dipole magnet resembling, for example, dipole magnet 250 of
Magnet-sensor combination 1400 also includes an electrical terminal 1430 for electrically powering magnetic field sensor 1420 by a power source that may be located in the RP of the pump device, and for transferring the output signal of magnetic field sensor 1420 to a controller of the related RP, for example to the controller that is located in main body 1330 of RP 1310. (The power source and the controller are not shown in
Common to all magnets, sensor's sensing plane and AMPs in all the drawings is that they are all in the X-Z plane (or parallel to the X-Z plane), with the Y-axis being normal (orthogonal) to their planes. Another feature that is common to all magnets, magnetic field sensors and AMPs is that the asymmetry line of the AMP (for example asymmetry line 780 of AMP 700, asymmetry line 880 of AMP 800) coincides with (or is parallel to) the Z-axis. Orienting the magnet, sensor's sensing plane and AMP in the way shown in the drawings and described herein facilitates optimization of the magnetic disruption by the AMP, hence the sensing and detection of the engagement state (including engagement orientation) by the controller of the pump device.
The RP includes a magnet-sensor combination similar to magnet-sensor combination 1400 of
A magnet-sensor combination 1600 includes a magnet 1610 and magnetic field sensor 1620. Magnet-sensor combination 1600 and AMP 1630 are designed such that when the related DP and RP of a pump device are engaged, tab 1650 partially overlaps magnetic field sensor 1620. (The greater the inward protrusion 1640 of tab 1650; i.e., the greater the value of X1 in
If the overlap percentage is zero (if X1=0), the disruption that tab 1650 causes to the magnetic field(s) produced by magnet 1610 may not be detectable by magnetic field sensor 1620, or the difference between the sensor's output signal in the ‘disengagement’ state and the sensor's output signal in the ‘engagement’ state may be too small for a controller to reliably distinguish between the two states. In addition, if X1=0 the magnetic attraction force that is induced between tab 1650 and magnet 1610 may be weak for proper attachment of the DP to the RP of the pump device. On the other hand, a configuration in which X1=X2 also poses an issue that is related to the disruption (magnetic deflection) that the AMP induces in the magnetic field(s). That is, if the overlap percentage is 100%, or near 100%, the disruption that tab 1650 induces in the magnetic field(s) produced by magnet 1610 may be so great that magnetic field sensor 1620 may enter saturation state even before the DP and the RP of the pump device are engaged. As a result of this, the output signal (saturation value) of magnetic field sensor 1620 may erroneously be interpreted by the controller as indicating engagement of the DP and RP even before engagement occurs. Briefly, a sensor's saturation is a state in which the actual signal that needs to be measured is unmeasurable because it exceeds the output dynamic range of the sensor. Therefore, the saturation value of the sensor's output becomes a limiting value of the sensor's dynamic output range. (The lower the sensor's saturation value, the smaller the sensor's dynamic output range.) In addition, if X1=X2, the magnetic attraction force that is induced between tab 1650 and magnet 1610 may be too strong for a user (e.g., PD patient) to disengage the DP from the RP of the pump device.
Turning to
Given the two constraints (i.e., detectable magnetic disruption and preferable magnetic attraction force), the value of X1 should preferably be greater than zero to obtain a strong enough magnetic attraction force and a detectable magnetic disruption, and smaller than X2 to prevent a too strong magnetic attraction force and/or entering saturation (i.e., X1 has to meet the condition 0<X1<X2). A traded off overlapping value may be, for example, 50% (i.e., X1=X2/2). The two constraints mentioned with regard to the overlap percentage, P, apply also to AMP 500, AMP 600, AMP 700, and AMP 800, as well as to AMPs of other designs.
Turning back to
This feature can enhance the usability of the pump device 1300 because a patient does not need to be hassled by the orientation between RP 1310 and DP 1320 when attaching the two parts. In other embodiments, though, RP 1310 and DP 1320 may have to be engaged in a particular orientation in order to make the pump device operable. According to the present invention, ensuring that the engagement orientation of the DP is the operational orientation may be done by using the asymmetry feature of the asymmetrical metal plate (AMP), as described herein.
As described herein and shown in the drawings, asymmetrical metal plates (AMPs) are asymmetric with respect to the Z-axis (see, for example, AMPs 500, 600, 700, 800 and 1630). Therefore, rotating the DP of a pump device 180 degrees in the X-Z plane (rotating it about the Y-axis) relative to the RP also rotates the AMP 180 degrees in the X-Z plane (about the Y-axis) relative to the magnetic field sensor. Thanks to the asymmetry of the AMP with respect to the Z-axis, the magnetic disruption that the AMP induces in the magnetic field(s) at the sensor in the first engagement orientation differs from the magnetic disruption induced by the AMP at the sensor in the second engagement orientation. Consequently, the output signal of the Hall effect sensor for the first engagement orientation differs from the output signal of the Hall effect sensor for the second engagement orientation. Therefore, the output signal of the magnetic field sensor with respect to the null voltage (null point 1710 in
Curve 1810 represents the sensor's output value (i.e., digital value) as a function of the distance, or gap/spacing, between the AMP and the sensor when the AMP is oriented in a first orientation relative to the sensor. (The first orientation is referred to herein as orientation ‘SIDE-B’). Curve 1812 represents the sensor's output value as a function of the distance, or gap/spacing, between the AMP and the sensor when the AMP is oriented in a second orientation (‘SIDE-A’) relative to the sensor. (The second orientation is referred to herein as orientation ‘SIDE-A’). The second orientation (‘SIDE-A’) of the AMP is obtained by rotating the AMP 180 degrees in the X-Z plane, about the Y-axis. (See plane X-Y and the Y-axis in, for example,
Referring to curve 1810, when the AMP is distanced away from the magnetic field sensor to a distance greater than 3.6 mm (in this example), the sensor's output value (a digital code/value, Sa) is its null value Snull (Snull=˜1,060), because at a distance greater than 3.6 mm the AMP does not disrupt the magnetic field(s) at the sensor, so the net magnetic field sensed by the sensor is zero, or near zero, which corresponds to the sensor's null value ˜1,060. (Null line 1830 corresponds to null value Snull=˜1,060 of the sensor.) However, as the AMP (in orientation ‘SIDE-B’) is brought closer to the sensor, the magnetic disruption caused by the AMP gradually increases, which results in a corresponding increase in the sensor's output value, until at zero distance the sensor outputs the upper saturation value ‘2014’ (saturation point 1814 in
Referring to curve 1820, it illustrates a similar dependency between spacing (between the AMP and the sensor) and the sensor's output value as curve 1810. Namely, as the AMP (also in orientation ‘SIDE-B’) is continually brought closer to the sensor, the magnetic disruption caused by the AMP gradually increases, which results in a corresponding increase in the sensor's output value, until at zero distance the sensor outputs the non-saturation value ‘1699’ (point 1824 in
The safety margin is useful, for example, in detecting a malfunctioning sensor (or another component of the electrical circuit) by a controller of the RP of the pump device when the DP and the RP of the pump device are engaged. For example, if the DP and RP of the pump device are engaged but the sensor outputs the saturation value, the controller may determine that the sensor, or some other electrical component, does not function properly, and, accordingly, may respond by outputting (audibly and/or textually) a warning message for the patient and simultaneously stop delivering medicament from the pump device to the patient. (This feature is useful for all malfunctions that, upon occurrence, cause the magnetic field sensor to enter the saturation state.) So, in terms of detecting malfunctions, using a ‘non-saturation’ curve similar to curve 1820 is beneficial comparing to using a saturation curve similar to curve 1810.
Referring to curve 1812, when the AMP is distanced away from the magnetic field sensor to a distance greater than 3.6 mm (in this example), the sensor's output value is its null value/point (˜1,060) because at a distance greater than 3.6 mm the AMP does not disrupt the magnetic field(s) at the sensor, so the net magnetic field sensed by the sensor is zero, or near zero, which corresponds to the sensor's output value ˜1,060. However, as the AMP (this case in the ‘SIDE-A’ orientation) is brought closer to the sensor, the magnetic disruption caused by the AMP gradually increases, which results in a corresponding increase in the sensor's output value, until at zero distance the sensor outputs the low saturation value ‘0’ (point 1816 in
Referring to curve 1822, it illustrates a similar dependency between spacing (between the AMP and the sensor) and the sensor's output value as curve 1812. Namely, as the AMP (in orientation ‘SIDE-A’) is continually brought closer to the sensor, the magnetic disruption caused by the AMP gradually increases, which results in a corresponding increase in the sensor's output value, until at zero distance the sensor outputs the non-saturation value ‘277’ (point 1826 in
A magnitude, ‘M’, of the sensor's output for each distance between the AMP and the sensor may be calculated as M=|Sa−Snull|, where ‘Sa’ is the sensor's actual (e.g., measured) output value, and ‘Snull’ is the sensor's null value. Regarding ‘saturation’ curves 1810 and 1812, the sensor's output magnitude M for zero distance in the first orientation (curve 1810, ‘SIDE-B’) of the AMP is 954 (M=|2014−1060|=954). In the second orientation (curve 1812, ‘SIDE-A’) of the AMP, the sensor's output magnitude M for zero distance is 1060 (M=|0−1060|=1060). Regarding ‘non-saturation’ curves 1820 and 1822, in the first orientation (curve 1820, ‘SIDE-B’) of the AMP the sensor's output value M for zero distance is 639 (M=|1699−1060|=639), and in the second orientation (curve 1822, ‘SIDE-A’) of the AMP the sensor's output value M for zero distance is 783 (M=|277−1060|=783).
The sensor's output magnitude, ‘M’, or span, for non-saturation curves is smaller comparing to the sensor's output magnitude, ‘M’, or span, for saturation curves. However, as described herein, non-saturation curves provide a useful safety margin. The safety margin may be designed as a tradeoff between the sensor's output magnitude, ‘M’, and the ability of the pump's controller to detect a faulty magnetic field sensor and/or other circuit components. In other words, it would be beneficial to increase the value of M without sacrificing the controller's ability to detect a faulty magnetic field sensor, and/or other circuit components, by using the sensor's saturation value(s).
As described in connection with
Curves 1812 is roughly a mirror image of curve 1810 with respect to null line 1830. Similarly, curve 1822 is roughly a mirror image of curve 1820 with respect to null line 1830. ‘Mirror’ curves such as curves 1812 and 1822 are the result of the AMP being asymmetrical, with the asymmetry line coinciding with the Z-axis. Imparting asymmetry to the AMP and positioning (subtending) the AMP against the sensor (and against the magnet that surrounds the sensor) such that the AMP's asymmetry line is perpendicular to the X-axis enables to reverse the direction of the magnetic field that is sensed by the magnetic field sensor due to the magnetic disruption caused by the AMP. That is, if the AMP is positioned against (if it subtends) the sensor in orientation ‘SIDE-B’, the magnetic field that the sensor senses due to the magnetic disruption of the AMP is in a first direction, which results, in this example, in curve 1820. However, if the AMP is rotated 180 degrees with respect to the Y-axis (i.e., positioned in orientation ‘SIDE-A’), the direction of the magnetic field that the sensor senses due to the magnetic disruption of the AMP at this orientation is reversed, which results, in this example, in curve 1822.
Applying curve 1810 (
Assuming that the saturation value of magnetic field sensor 1560 is 2014 (per sensor response curve 1810), AMP 1570 may be designed such that curve 1810 reaches the sensor's saturation value 2014 when the spacing between AMP 1570 and sensor 1560 is zero, or near zero. On the one hand, designing AMP 1570 to cause the sensor's output value to be its saturation value (in this example 2014) for zero spacing means maximizing the resolution of the spacing measurement, hence spacing measurement precision. On the other hand, if the DP and the RP are engaged (if the spacing between them is zero) but the sensor, or associated electronics, is faulty or it malfunctions, the faulty condition cannot be detected by using the sensor's output signal because the saturation output value of the sensor can be used to detect (i.e., be associated with) either a zero spacing between an AMP and a sensor (i.e., detect engagement state), or a circuit problem, but not both. To enable using the sensor's output signal to detect both zero (or near zero) AMP-sensor spacing and a faulty sensor, electronics or software, AMP 1570 can be designed in a way that the sensor's output value would be ‘slightly’ lower (e.g., 1699, per sensor response curve 1820) than the sensor's saturation output value 2014 when the spacing between AMP 1570 and sensor 1560 is zero, or near zero. Curve 1820 solves this problem because, on the one hand, the sensor's output value 1699 indicates when the AMP-sensor distance is zero (or near zero), and, on the other hand, in case the sensor and/or any other system component, is faulty, the sensor's output would ‘jump’ to its saturation valuc. So, when the DP and RP of the pump device are engaged, the two sensor output values 1699 and 277 enable (e.g., the controller in the RP) to distinguish the engagement state from a malfunctioning condition. AMP 1570 (for example) can be designed accordingly to impart this kind of ‘under saturation’ output-distance response curve to sensor 1560.
Comparing curves 1910 and 1930 shows that the design of AMT #1 is beneficial over the design of AMP #2 because the sensor's output range (magnitude M) resulting from design AMP #1 is significantly larger in span at the zero spacing (e.g., 1773−1040=733) than the sensor's output range resulting from design AMP #2 at the same spacing (i.e., 1514−1040=474). Comparing the respective ‘mirror’ curves 1920 and 1940 shows similar behavior. (Sensor's output value 1040 is the sensor's null value corresponding to null line 1950.) In addition, the design of AMP #1 provides a greater magnetic attraction force comparing to the design of AMP #2, and this magnetic property applies both to the 2-pole magnet configuration and to the 4-pole magnet configuration, as the specific example comparative information below demonstrates:
Example factors to be considered when designing an AMP:
The different design of these two AMPs (AMP #1 and AMP #2) causes the sensor to respond differently for the same distance between the AMPs and the sensor. For example (referencing the ‘SIDE-B’ orientation in
During normal operation of the pump device the controller of the pump device determines the distance, Da, between the AMP and the magnetic field sensor from the sensor's output valuc. Since the relationship between the sensor's output value and the related distance/spacing between the AMP and the sensor vary from one pump design to another, a calibration process has to be performed in order to associate the sensor's threshold output value (Sth) with a threshold distance (Dth) that are specific to the pump device that is the subject of the calibration. Briefly, calibration is performed by engaging the DP with the RP and reading the sensor's output value (Sth) corresponding to the engagement distance. Assuming that the engagement orientation is ‘SIDE B’, any sensor's output value that is equal to or greater than the value of Sth during normal operation of the pump device would indicate that the DP and RP of the pump device are engaged. The calibration described herein applies to any design of AMP, magnetic field sensor, magnet, DP and RP of a pump device.
Curve 2010 represents an output value of a sensor (e.g., sensor 1560 of
As described herein in connection with the two engagement orientations (‘SIDE-A’ and ‘SIDE-B’) of the AMP, the second engagement orientation (‘SIDE-A’) of the AMP is obtained by rotating the AMP 180 degrees in the X-Z plane, about the Y-axis. (The X-Y-Z coordinate system used, for example, in
At a first calibration step, a DP including an AMP is engaged in a first engagement orientation (e.g., orientation ‘SIDE-B’) with a RP including a magnet, a magnetic field sensor and a controller, and the magnetic field sensor outputs a first value, Sth1, that corresponds to the Engagement Threshold Distance (ETD), Dth. In this example the engagement threshold distance is 1.5 mm (i.e., Dth=1.5 mm), and the sensor's output value (engagement value, Sth1) corresponding to the aforesaid engagement distance is 1304 (i.e., Sth1=1304). All sensor output values, Sa, for the ‘SIDE-B’ orientation are above null line 2050 (i.e., all sensor's output values are greater than the null value ˜1110).
Any sensor's output value, Sa, that is equal to or greater than 1304 (Sth1) indicates that the engagement (in orientation ‘SIDE-B’) is maintained. If the sensor's output value, Sa, gets smaller than 1304, i.e., if 1110<Sa<1304 (‘1110’ is the sensor's null value, Snull), this indicates (e.g., to the controller) that the distance between the AMP and the sensor is greater than Dth (i.e., Da>Dth). This means that the DP and the RP of the pump device have been disengaged. So, the sensor's output value Sth1=1304 is a first calibration value that the controller of the pump device uses to distinguish between engagement state and disengagement state in the first orientation (the ‘SIDE-B’ orientation) of the DP relative to the RP.
At a second calibration step, the DP is engaged with the RP in the second orientation (e.g., the orientation corresponding to ‘SIDE-A’), and the magnetic field sensor outputs a second value, Sth2, that reflects the engagement state in the second orientation (‘SIDE-A’ orientation). In this example the engagement distance is also 1.5 mm (i.e., Dth=1.5 mm), and the sensor's output value (engagement value Sth2) is 1000 (i.e., Sth2=1000). (The engagement distance for both orientations is, in this example, 1.5 mm. However, depending on the design of the pump device, the engagement distance may change from one pump device to another, or from one engagement orientation to another.) All sensor output values, Sa, for the ‘SIDE-A’ orientation are below null line 2050 (i.e., all sensor's output values are smaller than the null value ˜1110).
Any sensor's output value, Sa, that is equal to or smaller than 1000 indicates that the engagement (in orientation ‘SIDE-A’) is maintained. If the sensor's output value, Sa, is greater than 1000, i.e., if 1000<Sa<1110 (‘1110’ is the null value, Snull), this is an indication that the DP and RP of the pump device have been disengaged. So, the sensor's output value Sth2=1000 is another calibration value that the controller of the pump device uses to distinguish between engagement state and disengagement state in the second engagement orientation (the ‘SIDE-A’ orientation) of the DP relative to the RP.
The controller of the pump device can, thus, determine two things from a single sensor's output value: (1) engagement state (“engaged”, “disengaged”), and (2) engagement orientation of the DP (engagement orientation ‘SIDE-B’ or ‘SIDE-A’). For example, a controller of the pump device may determine the engagement orientation (e.g., ‘SIDE-B’ or ‘SIDE-A’) of the DP relative to the RP by comparing the sensor's output value to the sensor's null value, Snull, and determining whether the sensor's output value is greater, equal to or smaller than the sensor's null value Snull. For example, if a sensor's output value, Sa, is greater than the sensor's null value (i.e., if Sa>Snull), the engagement orientation is ‘SIDE-B’, and if the sensor's output value is smaller than the sensor's null value (i.e., if Sa<Snull), the engagement orientation is ‘SIDE-A’.
Regarding determination of the engagement state (‘engaged’ or ‘disengaged’), if the sensor's output value, Sa, is equal to or greater than the first threshold value (i.e., if Sa≥Sth1), the controller determines that the DP is engaged with the RP in engagement orientation ‘SIDE-B’. Similarly, if the sensor's output value, Sa, is less than the second threshold value (i.e., if Sa<Sth2), the controller determines that the DP is engaged with the RP in engagement orientation ‘SIDE-A’.
So, during the calibration process the controller monitors the sensor's output value for both engagement orientations (‘SIDE-B’ and ‘SIDEA’) of the DP, and terminates the calibration process after having identified two engagement threshold values, Sth1 and Sth2, where each engagement threshold value corresponds to a specific engagement orientation. (Engagement threshold value Sth1 corresponds to engagement orientation ‘SIDE-B’, and engagement threshold value Sth2 corresponds to engagement orientation ‘SIDE-A’.) Then, the controller uses the two engagement threshold values (Sth1, Sth2) to detect the engagement orientation during normal operation of the pump device. The way the controller uses the two engagement threshold values is shown in
At step 2100, a DP of the pump device (e.g., DP 1310 of
At step 2120, the controller compares the value of Sa to the first engagement threshold value, Sth1, to check whether the DP and the RP are engaged in orientation ‘SIDE-B’. If the value of Sa is equal to or greater than the value of Sth1 (this condition is shown as “Y” at step 2120), the controller determines, at step 2130, that the DP is engaged with the RP in the ‘SIDE-B’ orientation, and continues to monitor, at step 2110, the value of Sa to check whether the engagement is maintained or disrupted. In case of disengagement, or disrupted engagement, if this occurs during delivery of medicament to the patient, the controller stops delivering the medicament and outputs (audibly and/or visually) a corresponding alarm to the pump user (e.g., a patient). However, if the value of Sa is smaller than the value of Sth1 (this condition is shown as “N” at step 2120), the controller determines that the DP is not engaged with the RP in the ‘SIDE-B’ orientation, and proceeds to check potential engagement in the ‘SIDE-A’ orientation.
At step 2140, the controller compares the value of Sa to the second engagement threshold value, Sth2. If the value of Sa is equal to or smaller than the value of Sth2 (this condition is shown as “Y” at step 2140), the controller determines, at step 2150, that the DP is engaged with the RP in the ‘SIDE-A’ orientation, and continues to monitor, at step 2110, the value of Sa to check whether the engagement is maintained or disrupted. In case of disengagement, or disrupted engagement, if this occurs during delivery of medicament to the patient, the controller stops delivering the medicament and outputs (audibly and/or visually) a corresponding alarm to the patient. However, if the value of Sa is greater than the value of Sth2 (this condition is shown as “N” at step 2140), the controller determines, at step 2160, that the DP is not engaged with the RP in any orientation (i.e., neither in the ‘SIDE-A’ orientation, nor in the ‘SIDE-B’ orientation), and continues to monitor, at step 2110, the value of Sa to detect the engagement state (‘engaged’, ‘engagement orientation’, ‘disengaged’) of the pump device at any given time. The controller may check the value of Sa continuously, using a predetermined time interval that may change, for example, according to the operation mode of the pump device. For example, during normal delivery of medicament to the patient the controller may check the value of Sa frequently, for example once every t1 seconds, and when the pump does not deliver medicament to the patient the controller may check the value of Sa less frequently, i.e., once every t2 seconds, where t2>t1. The value of t1 may be, for example, 0.05 second, 0.1 second, or 1.0 second, etc., and the value of t2 may be, for example, 5.0 seconds, 7.0 seconds, or 10.0 seconds, etc.
The invention disclosed herein may be incorporated, for example, in a wearable infusion pump device. It may occasionally occur that a user using such an infusion pump device may unintentionally, inadvertently, or accidently exert force on one of the RP and the DP, causing the two parts to disengage from one another momentarily and partially. Partly disengaging the DP from the RP means that the RP and DP are neither fully engaged nor fully disengaged. Partly separating between the DP and RP while the pump device operates (e.g., while it delivers a drug dose) may be detrimental to the operation of the pump device in terms of potential damages (e.g., wearing, breaking) to various parts of the pump device, in particular to moving parts that are involved in transferring the motor's power from the RP to the reservoir's plunger rod in the DP. To avoid this problem, the relationship between the sensor's actual output value (Sa) and the distance (spacing) between the RP and the DP is used to determine a ‘safe distance range’ (“SDR”) between the RP and the DP. (An example relationship between a sensor's actual output value, Sa, and a distance, D, between a RP and a DP is shown in
Engagement of the RP and DP is regarded as ‘full’, hence safely operational, if the distance between the RP and the DP is within the SDR, and as ‘partial’, hence non-safely operational, if the distance between the RP and the DP exceeds the SDR. Accordingly, if the actual distance measured (by the pump device's controller) between the RP and the DP exceeds the SDR, the controller of the pump device may momentarily stop operation of the pump device (e.g., stop delivering a drug dose) until the distance between the RP and the DP is, again, within the SDR, which indicates full engagement between the RP and the DP being resumed.
The SDR depends on (is derived from) the actual design and configuration of the various parts involved, for example size, shape, and location of the sensor in the RP and size, shape, and location of the AMP in the DP. By way of example, the SDR may include all RP-to-DP distances between 0.6 mm and 2.0 mm, so that if the RP-to-DP distance momentarily exceeds 2.0 mm, the pump device's (RP's) controller would pause (stop, suspend, withhold) the drug delivery, and resume delivery of the drug when the RP-to-DP distance is back within the SDR range.
At step 2210 the controller of the pump device monitors the output value, Sa, of the magnetic field sensor corresponding to the net magnetic field that is sensed by the magnetic field sensor, and, at step 2220, the controller determines the distance (spacing), D, between the DP and the RP from the value of Sa.
At step 2230 the controller compares the distance, D, to the predetermined SDR, and determines whether the value of D is within the predetermined SDR. The controller may transition between operating the pump device and pausing, or suspending, operation of the pump device based on the comparison result. That is, if the value of D is within the predetermined SDR (the condition is shown as “Y” at step 2230), the controller continues to operate, at step 2240, the pump device normally for example according to the intended treatment regimen and continue to monitor (2250) the value of Sa in order to detect changes, should there be any, in the distance D. If the value of D exceeds the predetermined SDR (the condition is shown as “N” at step 2230), the controller stops (suspends), at step 2260, operation of the pump device as a precaution measure to prevent damages to the moving parts of the DP or RP, or to both parts of the pump device. Operating the pump device when the distance D is within the SDR may include executing a treatment regimen. Stopping, or suspending, operation of the pump device when the distance D exceeds the SDR may include pausing execution of the treatment regimen until the distance D between the RP and DP is back within the SDR range.
Referring again to step 2230, the example transition criterion that the pump device's controller uses to determine whether operation of the pump device should proceed normally (e.g., per step 2240) or be suspended (e.g., per step 2260) is based on a comparison of the distance, D, between the DP and the RP of the pump device to the safe distance range (SDR). However, the transition criterion may also factor in the time factor. Namely, if the distance, D, between the DP and the RP of the pump device exceeds the SDR the controller may use a transition parameter that is a function of, for example, the deviation of the distance, D, between the DP and RP from the SDR, and the duration of the deviation. For example, if the value of D exceeds the SDR, the smaller the deviation of the distance D from the SDR (i.e., the closer is D to the SDR), the longer the time that the pump device can be at this state before the controller stops or suspends operation of the pump device. Inversely, if the value of D exceeds the SDR, the larger the deviation of the distance D from the SDR, the shorter the time that the controller allows the pump device to be in this state before the controller stops or suspends operation of the pump device. The rationale behind this is that the closer the distance, D, to the SDR, the lower the potential damage to the DP and to the RP, so the controller may allow the pump device to stay at this state for an extended period of time without risking the integrity of the pump device. Inversely, the greater the deviation of the distance, D, from the SDR, the greater the potential damage to the DP and to the RP, so the controller may allow the pump device to stay at the ‘risky’ state only for a relatively short period of time in order to avoid risking the integrity (e.g., mechanical integrity) of the pump device.
As described herein, when the DP and RP of the pump device are disengaged, the net magnetic field that the magnetic field sensor (e.g., Hall effect sensor) senses should be zero irrespectively of the number of magnetic poles or magnetization direction(s) of the magnet. To facilitate this feature, the magnetic field sensor is centered in the magnet and positioned with its sensing plane arranged according to the magnetization configuration (e.g., dipole, 4-pole) of the magnet. For example, in case of dipole magnetization (
The difference between dipole magnetization and multipole magnetization (the 4-pole magnetization described herein is a special case of multipole magnetization) is the undisrupted (i.e., the genuine) direction(s) of the magnetic field flux lines with respect to the sensor's sensing plane. (‘Undisrupted direction’, or ‘original direction(s)’, means the direction(s) of magnetic field flux lines when the DP and the RP of the pump device are disengaged. The undisrupted direction(s) of the magnetic fields change (are disrupted) at the magnetic field sensor, i.e., deflected/redirected, by the AMP as the DP and RP of the pump device are engaged.)
To facilitate generation of a magnetic attraction force between an AMP and a magnet, the AMP is made from a ferrous material. For example, iron, cobalt and nickel, as well as alloys composed of these ferromagnetic metals, are strongly attracted to magnets. As described herein, in addition to inducing magnetic attraction force AMPs have another function, which is deflecting (redirecting) magnetic field lines at the magnetic field sensor when the DP and RP of the pump device are engaged. To facilitate the latter feature, the material selected for the AMP is characterized by having a relatively high magnetic permeability. (The higher the magnetic permeability of an AMP, the greater the number of magnetic force lines deflected by the AMP, hence the greater the deflection effect of the AMP.) So, AMPs include a metal that is magnetizable and conducts magnetic flux when they are near the magnet (i.e., when the DP is engaged with the RP of the pump device) but they do not become magnetized by the magnet or conduct magnetic flux when the AMP is distanced away from the magnet (i.e., when the DP is disengaged from the RP of the pump device).
The magnet shown in various drawings (for example magnet 110 in
The magnetic field sensor shown in various drawings (for example sensor 120 in
The articles “a” and “an” are used herein to refer to one or to more than one (e.g., to at least one) of the grammatical object of the article, depending on the context. By way of example, depending on the context, “an element” can mean one element or more than one element. The term “including” is used herein to mean, and is used interchangeably with, the phrase “including but not limited to”. The terms “or” and “and” are used herein to mean, and are used interchangeably with, the term “and/or,” unless context clearly indicates otherwise. The term “such as” is used herein to mean, and is used interchangeably, with the phrase “such as but not limited to”.
Having thus described exemplary embodiments of the invention, it will be apparent to those skilled in the art that modifications of the disclosed embodiments will be within the scope of the invention. Alternative embodiments may, accordingly, include functionally equivalent objects/articles. For example, an asymmetrical metal plate (AMP) may have a different design (e.g., different shape, size and/or material) comparing to the AMPS described herein and shown in the drawings, provided that the different designs of the AMP function in the way(s) described herein. Typically, the disposable part of the pump device may include one medicament reservoir or two medicament reservoirs, and each medicament reservoir may contain levodopa or carbidopa, or a combination of levodopa and carbidopa. Any permanent magnet may be used, provided that it functions in the way described herein. Features of certain embodiments may be used with other embodiments shown herein. The present disclosure is described in connection with pump devices that include a DP and a RP. However, the present disclosure may be relevant to (e.g., it may be implemented by, used with or for) other types of ‘two-part’ devices, such as pumps, syringes, therapeutic drug dispensing devices, and the like. Hence the scope of the claims that follow is not limited by the disclosure herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IL2023/050147 | 2/13/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63316641 | Mar 2022 | US |
