WO2015148833A1

WO2015148833A1 - Voice coil activated pump

Info

Publication number: WO2015148833A1
Application number: PCT/US2015/022801
Authority: WO
Inventors: Clark Foster; Marc Lalouette; David J. Mishelevich
Original assignee: Sparton Aubrey Group, Inc.
Priority date: 2014-03-26
Filing date: 2015-03-26
Publication date: 2015-10-01
Also published as: WO2015148833A8

Abstract

A pump mechanism is described that uses a rotary or linear voice coil motor to provide the electromechanical actuation for the mechanism.

Description

TITLE

VOICE COIL ACTIVATED PUMP

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to United States provisional application number 61/970,898 filed March 26, 2014 the contents of which are hereby incorporated by reference.

INCORPORATION BY REFERENCE

All publications, including patents and patent applications, mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually cited to be incorporated by reference.

FIELD OF THE INVENTION

[0001] This invention relates generally to pumps, and in particular to micropumps configured to be wearable where power efficiency of pumping and cost are important.

BACKGROUND

[0002] Many medical applications require a very small, power-efficient pump. Insulin dispensing is one example of a medical application of such a pump. Patents publications that relate to the general subject matter include U.S. patent application 2013027902 on Electric control of piezo-electric pumps, and patent # 5,759,015 detail construction and control of piezoelectric pumps designed to serve this need. A principal drawback to these types of pumps is the relatively low electromechanical efficiency inherent in piezoelectric movement. In the field of disk drive computers, voice coil motors are known for high electrical efficiency and compact size, allowing their use in electronic media players (iPods and the like). US patents 6422080, 7206164 by Lalouette et al. detail improvements in voice coil motor driven actuator assemblies.

[0003] The current application will detail the construction of voice coil motor actuated pumping mechanisms suitable to meeting the needs of the wearable pump and other markets. SUMMARY OF THE INVENTION

[0004] The invention provides an efficient, compact, voice coil driven pumping mechanism, and its usage in connection to removable drug cartridges for dispensing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 illustrates an exploded view of an insertable drug cartridge.

[0006] FIG. 2 illustrates a driving mechanism into which the drug cartridge is inserted.

[0007] FIG. 3 illustrates a voice coil motor driven actuator with the catchment and engagement features.

[0008] FIG. 4 illustrates a magnet circuit with a magnetic force bearing ball supporting the magnetic force of attraction between the magnet and the backing plate.

[0009] FIG. 5 illustrates the housing with the drug cartridge inserted and engaged.

[0010] FIG. 6 illustrates a peristaltic tubing version of the invention.

[0011] FIG. 7 illustrates an inertial latch to prevent inadvertent pumping during shock events.

[0012] FIG. 8 Illustrates a diaphragm driven insertable cartridge.

[0013] FIG. 9 illustrates a VCM driven diaphragm pump driver capable of actuating the cartridge of FIG. 8.

[0014] FIG. 10 illustrates the VCM pump of FIG.9 inserted into the cartridge of FIG.8

[0015] FIG. 11 shows a VCM-activated pump that does not have a removable cartridge.

[0016] FIG. 12 illustrates an insertable cartridge with a VCM driving a diaphragm cartridge, whereby the coil 95 is supported by a linear ball bearing 121 instead of a diaphragm 97.

[0017] FIG. 13 illustrates a variation of a linear ball bearing VCM driving motor, whereby the pouch 82 is in close proximity to the outer diameter of the VCM driving motor, whereby achieving smaller overall package size. [0018] The objects and features of the invention can be better understood with reference to the claims and drawings described below. The drawings are not necessarily drawn to scale, and the emphasis is instead generally being placed upon illustrating the principles of the invention. Within the drawings, like reference numbers are used to indicate like parts throughout the various views. Differences between like parts may cause those parts to be indicated by different reference numbers. Unlike parts are indicated by different reference numbers.

DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 illustrates an exploded view of an embodiment of a removable drug cartridge for a wearable dispensing device. 1 is the housing of the drug cartridge. In one embodiment, this housing is made of polypropylene to take advantage of its low friction properties for enabling a snap fit into the mating housing. 2 is a plunger that moves axially towards 1 whereby squeezing the drug pouch 5, forcing liquid out of the cartridge through a valve 7 or a constricted orifice. In one embodiment, the plunger 2 is made from

polypropylene, delrin® or other low friction plastic to reduce friction between the plunger and the housing. 6 is a screw that is embedded into the drug cartridge housing 1 and passes through the drug pouch 5 and plunger 2 to engage on a nut 4 that is attached to a circular gear 3. In one embodiment the screw is stainless steel and has a metric Ml thread to provide mechanical advantage to the gear mechanism.

[0020] FIG. 2 illustrates an exploded view of a VCM and housing to receive the drug cartridge of FIG.1. A housing 10 is used to mount a controllable voice coil motor. The elements of the voice coil motor are an actuator 11 onto which a coil 12 is mounted. These sit in immediate proximity to a magnet 14 and magnetic supporting structure 13 which are permanently mounted in the housing 10. In one embodiment, the coil has between twenty and 200 turns made from 0.001"- 0.005" copper wire to maximize generated torque and minimize electrical resistance. The actuator pivots around a hole 19 into which a shaft is placed into a mating hole 20 in the housing 10. In some embodiments, the shaft can be either solid steel, a low friction plastic element or be supported by a ball bearing to minimize friction. This allows the actuator 11 to rotate when a force is imparted on it by the attached coil 12, driving the circular gear 3 causing the insertable cartridge FIG. 1 to dispense a fluid. A secondary latch 16 can be employed to engage against the cartridge circular gear 3 to prevent backwards rotation of the gear 3. In one embodiment the secondary latch 16 is made from 0.005"- 0.025" diameter wire to provide a light spring force against the gear 3 when rotating, preventing backward rotation of the gear while introducing a minimal amount of additional friction. In another embodiment, the secondary latch 16 is comprised of a feature molded into the housing 10.

[0021] FIG. 3 illustrates the actuator. It is comprised of a pivot hole 19, a catchment 21, catchment lead in feature 22, catchment load spring 23. The actuator has two opens 24a, 24b which serve to capture and form raceways for 2 ball bearings 15a and 15b. When the drug cartridge is inserted axially into the housing, the catchment lead in feature 22 is deflected by the drug cartridge gear 2 such that the gear 2 slides past the catchment lead in 22, until it comes to rest fully inserted into the body, with the catchment 21 biased against the gear 2 by the catchment load spring 23.

[0022] FIG 4. Illustrates the magnet circuit of the voice coil motor. In one embodiment the actuator can be made from a material with magnetic permeability between 1.3 and 0.001 microHenry/meter, such as Stainless 430, Mu metal or cold rolled steel, such that it assists in closing the magnetic circuit between the magnet, through the magnet plate supporting structure 13, ball bearings 15a, 15b, which are also make of material with magnetic permeability between 1.3 and 0.001 microHenry/meter to maximize the torque and electrical efficiency of the voice coil motor ("VCM").

[0023] FIG. 5 illustrates the housing with the disposable drug cartridge FIG.l in place, with the actuator catchment 21 engaged against the cartridge gear 3 such that it will advance the gear, acting to dispense the drug.

[0024] FIG. 6 illustrates a peristaltic cartridge where a cartridge body 30 contains a gear element 31 a collapsible tube 32 and a compressive roller element 33. The compressive roller element 33 is biased against the outer surface of the cartridge body 30 such that when the cartridge body 30 is advanced by the catchment the compressive roller element 33 advances forward on the collapsible tube 32 driving the fluid from the collapsible tube 32 out of the cartridge.

[0025] FIG 7. Illustrates an inertial latch that acts to prevent inadvertent rotation of the gear 3 and subsequent pumping action during shock events. During shock events, the inertia of the inertial latch 60 causing the engagement area 61 to move towards and engage the actuator 11 engagement area 62. In one embodiment, the inertial latch can be molded into the housing as shown. In another embodiment, the inertial latch can be a separate piece, biased by a spring. In another embodiment, the inertial latch can be a separate piece, with a restraining force applied by a small magnetic slug attached to it that is attracted to the VCM magnet or plate in an advantageous geometry.

[0026] In another embodiment, the actuator 11 has a feature that acts to open the drug pouch 5 valve 6 to reduce the flow resistance of the valve to improve the energy efficiency of the pumping action.

[0027] FIG. 8 illustrates a cross sectional view of an embodiment of a removable cartridge that has a driven- valve feature integrated into it. 81 is a housing that the other components mount in. 82 is a collapsible pouch that is filled with a liquid solution. 83 is a channel that allows liquid to flow between the collapsible pouch and the voice-coil actuated diaphragm pump. A diaphragm membrane 84 is biased in the distended position by means of a poppet valve spring 85 and washer 86. These in turned are connected to a poppet valve 87, such that when the cartridge is not externally actuated, the bias force of the spring acts to load the valve seat of the poppet valve holding the cartridge shut and preventing liquid from escaping. A one-way flapper valve 88 acts to ensure that liquid is not pumped back into the collapsible pouch 82 when the diaphragm is externally driven against the force of the spring, causing it to move towards the housing 81. This action pushes the poppet valve open, allowing liquid to be egressed from the diaphragm cartridge of FIG.8. Another one way flapper valve 89 acts to prevent liquid from being drawn back into the cartridge on the return stroke of the diaphragm, ensuring that liquid is drawn from the collapsible pouch 83. In another embodiment, the cartridge liquid egress path has a sufficiently high flow restriction to reduce or eliminate the need for a second flapper valve 89 on the cartridge.

[0028] FIG. 9 illustrates a cross sectional view of an actuating VCM mechanism for the removable cartridge FIG. 8 that uses a voice coil motor (VCM) comprised of a housing 91 that acts to provide structure to the device and is inserted in housing 81 of the removable cartridge of FIG. 8. In one preferred embodiment, the housing 91 is made of magnetic steel such that it acts to concentrate magnetic force in the active area of the VCM. The housing 91 also acts as a mount for a permanent magnet 94, secondary magnetic guide 92, a diaphragm 97 and printed circuit board 96. On the surface of the magnet is a top pole piece 93 that also acts to concentrate the magnetic field in an area containing a coil 95, which is electrically driven by the printed circuit board 96. The coil is mounted to the diaphragm 97 such that it is free to travel vertically. When electricity passes through the coil, it generates a vertical force that drives the diaphragm up and down. [0029] FIG. 10 illustrates a cross sectional view of the removable cartridge FIG. 8 with the actuating VCM mechanism of FIG. 9. The diaphragm of the VCM mechanism is shown in the withdrawn position. When the cartridge of FIG. 8 is inserted onto the actuating VCM mechanism of FIG. 9 the cartridge poppet valve spring 85 acts to hold the cartridge diaphragm 84 in the distended position. This in turn acts upon the actuating VCM mechanism diaphragm 97 pushing it and the coil upward into a known state and position, such that when voltage is applied to the coil, a known pumping volume will occur during the first actuation. In one embodiment, the poppet valve compression spring 85 is set to produce a valve seating force that is in the range of 1% to 95% of the available actuation force provided by the VCM mechanism of FIG.9. A benefit of the invention is the known volume of fluid that is expelled each time with both precision and accuracy.

[0030] FIG. 11 illustrates a cross sectional view of a VCM activated pump that does not have a removable cartridge, but instead acts directly upon the fluid to be pumped.

[0031] FIG. 12 illustrates an insertable cartridge with a VCM driving a diaphragm, whereby the coil 95 is supported by a linear ball bearing 121 instead of a diaphragm 97.

[0032] FIG. 13 illustrates a variation of a linear ball bearing VCM driving motor, whereby the pouch 82 is in close proximity to the outer diameter of the VCM driving motor, whereby achieving smaller overall product volume.

[0033] While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

CLAIMS We Claim:

1. A pump, whereby the pump is driven by a voice coil motor.

2. The pump of claim 1, whereby the VCM is contained separately from the pumping fluid, such that there is no contact between the VCM mechanism and the fluid.

3. The pump of claim 2, whereby the fluid acted upon is contained in a removable cartridge.

4. The pump of claim 3, whereby the removable cartridge is acted upon by the VCM by means of a ratcheting gear.

5. The pump of claim 3, whereby the engagement catchment of the VCM has a lead in chamfer engagement feature for engaging with the fluid cartridge as it is slid in axially into a housing element for the VCM.

6. A voice coil motor, whereby the magnetic circuit is completed by magnetically loaded members.

7. The VCM of claim 6, whereby the magnetically loaded member rolls to reduce friction.

8. The VCM of claim 6, whereby the magnetically loaded member is a ball bearing.

9. A drug dispensing cartridge, whereby the drug cartridge contains a housing, plunger, and a collapsible fluid reservoir.

10. The drug dispensing cartridge of claim 9, whereby the means of egressing the drug from the cartridge is by means of small controlled resistance openings in the bag.

11. The pump of claim 2, whereby the active element being acted upon by the VCM consists of a diaphragm.

12. The pump of claim 2, whereby the active element being acted upon by the VCM is a peristaltic roller which squeezes a compressible tube to dispense the liquid.

13. The pump of claim 2, whereby the actuator is arrested during shock events by means of an inertially deployed latch.

14. The pump of claim 2, whereby the VCM actuator acts to actively open a valve that releases the liquid from the cartridge.

15. An insertable liquid cartridge dispensing device, whereby the insertable cartridge is acted upon by a Voice Coil Motor (VCM) driven actuator, whereby the coil is supported by a linear bearing assembly.

16. A VCM driven diaphragm pump, whereby the actuator motion that drives the diaphragm also directly mechanically drives a valve that allows liquid to escape from the cartridge.

17. The pump of claim 16, whereby the valve is acted upon by a spring that biases it in the closed position, such that the seating force is between 1 percent and 99 percent of the driving force capable of being produced by the VCM actuator.

18. The pump of claim 17, whereby the liquid is contained in an insertable cartridge such that the driving actuator does not contact the liquid.

19. The pump of claim 16, whereby the driven valve in the open and partially closed positions constricts flow between 1 and lOOOx that of the fluid pathway between the diaphragm chamber and the vessel containing the liquid to be pumped.

20. The pump of claims 17, whereby the driven valve in the open and partially closed positions constricts flow between 1 and lOOOx that of the fluid pathway between the diaphragm chamber and the vessel containing the liquid to be pumped.