Patent Application
20170095610
The technical field of this disclosure is personal medical systems, particularly, personal injection devices.
Certain medical conditions or diseases require that patients intermittently inject a drug or therapeutic agent subcutaneously to maintain the medical condition or disease under control. Multiple daily injections (MDIs) may be required. One such medical condition is diabetes, for which insulin is injected to regulate blood glucose. An estimated twenty-six million people in the United States, or about 8% of the population, have diabetes. This percentage is expected to increase in the near-term as the population ages.
Insulin pump therapy uses an insulin pump to deliver insulin slowly and continuously throughout the day as basal injections. Unfortunately, delivering fluid continuously and accurately over long periods of time currently requires a complex device to perform and control the pumping. To operate, such complex devices typically employ a programmed microcontroller, which requires significant infrastructure in the form of memory, software, code, power management, and the like. This increases the cost and size of the insulin pump. Many patients are unwilling or unable to use such complex insulin pumps due to the expense, complication, and obtrusiveness.
It would be desirable to have a personal injection device that would overcome the above disadvantages.
One aspect of the invention provides a personal injection device wearable by a user to deliver fluid from a reservoir to the user, the personal injection device including: a quartz oscillator operable to generate a constant frequency signal; a control circuit operably connected to the quartz oscillator, the control circuit being operable to generate a drive signal in response to the constant frequency signal; a stator operably connected to the control circuit and defining a rotor gap, the stator being operable to generate an oscillatory field in the rotor gap in response to the drive signal; a magnetic rotor disposed in the rotor gap, the magnetic rotor being operable to rotate in response to the oscillatory field; and a pump operably connected to the magnetic rotor, the pump being operable to move the fluid from the reservoir to the user in response to the rotation of the magnetic rotor.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention, rather than limiting the scope of the invention being defined by the appended claims and equivalents thereof.
Like elements share like reference numbers in the various drawings.
The personal injection device 100 includes a quartz oscillator 110, a control circuit 120 operably connected to the quartz oscillator 110, a stator 130 operably connected to the control circuit 120 and defining a rotor gap 132, a magnetic rotor 140 disposed in the rotor gap 132, and a pump 150 operably connected to the magnetic rotor 140. The pump 150 receives fluid from a reservoir 160 and provides the fluid to a user 170. A battery 180 operably connected to the control circuit 120 provides power for the personal injection device 100. In one example, the battery 180 is a button cell battery.
The quartz oscillator 110 generates a constant frequency signal, which is provided to the control circuit 120, which generates a drive signal in response to the constant frequency signal. The quartz oscillator 110 can receive an excite signal from the control circuit 120 to drive the quartz oscillator 110 at its natural frequency. The stator 130 receives the drive signal and generates an oscillatory field in the rotor gap 132 in response. A coil 134 of the stator 130 can receive the drive signal, which can be intermittently on or off to create the oscillatory field from the stator due to the drive signal and the magnetic field from the magnetic rotor 140. The magnetic rotor 140 rotates within the rotor gap 132 in response to the oscillatory field. The pump 150 operably connected to the magnetic rotor 140 moves the fluid from the reservoir 160 to the user 170 in response to the rotation of the magnetic rotor 140.
Those skilled in the art will appreciate that the pump 150 can be any pump operable to provide a well regulated, metered flow of the fluid to the user 170. The pump speed and thus the fluid delivery rate of the pump 150 can be controlled electronically by altering the signals between the electrical components of the personal injection device 100 or mechanically by gear ratios of gear chains between the rotor 140 and the pump 150, if any. In one example, the personal injection device 100 further includes a slide potentiometer operably connected to the control circuit 120 to adjust the drive signal sent to the stator 130.
The components of the personal injection device 100 can be enclosed within a casing for convenience of the user 170. The reservoir 160 can be placed inside or outside of the casing as desired for a particular application. In one embodiment, the reservoir 160 is prefilled and the personal injection device 100 discarded after a single use when the reservoir 160 is empty. The pump 150 can be attached to the user 170 with an infusion set or with a cannula projecting from the personal injection device 100.
The reservoir 260 is a syringe having a syringe body 264 and a syringe plunger 266 slideably disposed in the syringe body 264. The pump 250 includes a gear chain 252 operably connected to the magnetic rotor 240; screw drives 254 operably connected to the gear chain 252; a syringe body carriage 256 operable to removably receive the syringe body 264; and a syringe plunger carriage 258 operable to removably receive the syringe plunger 266. The screw drive 254 engages one of the syringe body carriage 256 and the syringe plunger carriage 258, so that the rotation of the magnetic rotor 240 moves the syringe body carriage 256 relative to the syringe plunger carriage 258 to advance the syringe plunger 266 in the syringe body 264. The relative motion increases pressure in the reservoir to drive fluid to the user.
Those skilled in the art will appreciate that the syringe plunger 266 and the syringe body 264 only need to be moved relative to each other to force the fluid from the syringe, i.e., either the syringe plunger 266 or the syringe body 264 can be held in a fixed position. In one embodiment as illustrated in
The pump 350 includes a pump wall 352 defining a plenum 354 having a volume, the pump wall 352 including a first wall 356, a second wall 358 hinged to the first wall 356, and a bellows wall 360 connected between the first wall 356 and the second wall 358, the bellows wall 360 urging the first wall 356 toward the second wall 358; a cam 362 operably connected to the magnetic rotor (not shown), the cam 362 being rotatably disposed in the plenum 354 between the first wall 356 and the second wall 358; a first fluid supply path 364 including an inlet check valve 366 in fluid communication between the reservoir (not shown) and the plenum 354; and a second fluid supply path 368 including an outlet check valve 370 in fluid communication between the plenum 354 and the user (not shown). The first wall 356 follows the cam 362 so that the volume of the plenum 354 is maximized when the cam 362 is in a first position as illustrated in
In operation, the cam 362 rotates with the first wall 356 following. As the first wall 356 moves away from the second wall 358, the volume of the plenum 354 increases, decreasing the pressure within the plenum 354 and drawing fluid from the reservoir (not shown) through the first fluid path 364 and inlet check valve 366. The outlet check valve 370 prevents backflow from the user (not shown) into the plenum 354. As the cam 362 rotates further, the first wall 356 moves toward the second wall 358 and the volume of the plenum 354 decreases, increasing the pressure within the plenum 354 to force fluid from the plenum 354 through the second fluid path 368 and the outlet check valve 370 to the user (not shown). The inlet check valve 366 prevents backflow from the plenum 354 into the reservoir (not shown). The bellows portion of the bellows wall 360 controls the force of the first wall 356 on the cam 362. Those skilled in the art will appreciate that the profile of the cam 362 can be selected as desired for particular pumping characteristics.
Referring to
In operation, adjacent flexible fingers 466 trap a small volume of fluid at the inlet port 454 from the reservoir (not shown) and rotate the small volume around the annulus 462. When one of the flexible fingers 466 reaches the narrowed portion 464 of the annulus 462, the flexible finger bend backwards against the direction of rotation of the pump rotor 460, compressing the small volume between the bent flexible finger and the adjacent trailing flexible finger, increasing pressure at the outlet port 457 to drive the fluid to the user (not shown). Those skilled in the art will appreciate that size and radial spacing of the flexible fingers 466 can be selected to achieve desired pumping characteristics.
Referring to
It is important to note that
While the embodiments of the invention disclosed herein are presently considered to be preferred, various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is indicated in the appended claims, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.
