Patent Application
20240009383
The present disclosure relates to an interlock for a medical injector metering pump.
Wearable medical devices, such as automatic injectors, have the benefit of providing therapy to the patient at a location remote from a clinical facility and/or while being worn discretely under the patient's clothing. The wearable medical device can be applied to the patient's skin and configured to automatically deliver a dose of a pharmaceutical composition within a predetermined time period after applying the wearable medical device to the patient's skin, such as after a 27 hour delay. After the device delivers the pharmaceutical composition to the patient, the patient may subsequently remove and dispose of the device.
In one aspect or embodiment, a metering pump for a medical injector including a reservoir and a cannula includes a housing, a sleeve at least partially received within the housing, a piston at least partially received within the sleeve, and an interlock. The piston and the sleeve define a chamber, with the piston having a first position where the chamber has a first volume and a second position where the chamber has a second volume, and with the first volume larger than the second volume. The sleeve has a first rotational position where an inlet is in fluid communication with the chamber, a second rotational position where an outlet is in fluid communication with the chamber, and a third rotational position where the inlet and outlet are isolated from the chamber. The interlock includes an elastomeric member positioned on one of the sleeve and the housing and a protrusion positioned on the other of the sleeve and the housing, where engagement between the elastomeric member and the protrusion is configured to restrict movement of the sleeve until the sleeve overcomes a predetermined torque value.
The elastomeric member may be positioned on the housing and the protrusion is positioned on the sleeve. The elastomeric member may be elastically deformed by the protrusion when the sleeve is rotated relative to the housing. The elastomeric member may extend radially inward from the housing and the protrusion may extend radially outward from the sleeve, where the elastomeric member is compressed by the protrusion when the sleeve is rotated relative to the housing. The elastomeric member may be overmolded onto the housing.
The piston may be configured to rotate and axially move relative to the housing and the sleeve, where the piston is configured to rotate together with the sleeve relative to the housing. The piston may be connected to the sleeve via a pin received within a helical groove defined by the sleeve. The inlet may be configured to be in fluid communication with the reservoir of the medical injector, where the outlet is configured to be in fluid communication with the cannula of the medical injector. Rotation of the piston in a first rotational direction may be configured to aspirate a fluid within the chamber and move the sleeve from the first rotational position to the second rotational position, and rotation of the piston in a second rotational direction may be configured to pump a fluid within the chamber and move the sleeve from the second rotational position to the first rotational position, with the second rotational direction being opposite from the first rotational direction.
The interlock may be configured to generate a maximum torque at least equal to a difference of torque between maximum and minimum operating pressure of the metering pump while maintaining fluid communication between the chamber and the outlet. A torque profile provided by the interlock may be symmetric when the sleeve moves between the first and second rotational positions. A maximum torque provided by the interlock may be smaller when the sleeve is moved from the first rotational position to the second rotational position than when the sleeve is moved from the second rotational position to the first rotational position.
The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following descriptions of embodiments of the disclosure taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the disclosure, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner.
Spatial or directional terms, such as “left”, “right”, “inner”, “outer”, “above”, “below”, and the like, are not to be considered as limiting as the invention can assume various alternative orientations.
All numbers used in the specification and claims are to be understood as being modified in all instances by the term “about”. By “about” is meant a range of plus or minus ten percent of the stated value. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. The terms “first”, “second”, and the like are not intended to refer to any particular order or chronology, but instead refer to different conditions, properties, or elements. By “at least” is meant “greater than or equal to”.
Referring to
Two ports 30, 32 are provided relative to the housing 16, including an inlet port 30 through which medication can flow from a reservoir 58 (
Referring to
Under certain conditions, such as back pressure, it is possible that friction between the piston 22 and the sleeve 14 is sufficient to cause the sleeve 14 to rotate before the piston 22 and the coupling pin 20 reach either end of the helical groove 18, which could result in an incomplete volume of liquid being pumped per stroke. In order to prevent this situation, the interlock 36 prevents the sleeve 14 from rotating until the torque passes a predetermined threshold, as shown in
Referring to
As described above, the metering pump 10 can have two ports 30, 32 and related valve sub-assembly that controls when fluid enters and leaves the chamber 28 via the respective ports 30, 32. One of the ports is the inlet port 30 through which fluid, such as liquid medication, flows from the reservoir 58 into the metering pump 10 as the result of a pump intake or pull stroke. Fluid leaves the chamber 28 of the metering pump 10 through the outlet port 32 and flows toward the cannula 50 for administration as the result of a pump discharge or push stroke of the metering pump 10. The pump and valve actuator 62 can be a DC motor and gearbox assembly or other pump driving mechanism for controlling the plunger or piston 22 and other related pump parts, such as the sleeve 14, that may rotate relative to the translational movement of the piston 22. A microcontroller 64 can be provided with an integrated or separate memory device having computer software instructions to actuate, for example, rotation of the sleeve 14 in a selected direction, translational or axial movement of the piston 22 in the sleeve 14 for an aspirate or dispense stroke, and optionally the rotation of the sleeve 14 and piston 22 together during a valve state change as described in the above-referenced International Publication No. WO 2015/157174. The metering pump 10 and the interlock 36 may be the same as the metering pump and interlock shown and described in International Publication No. WO 2019/156848, which is hereby incorporated by reference it its entirety.
The interlock 36 of the metering pump 10 shown in
Referring to
In one aspect or embodiment, the metering pump 10 includes the housing 16, the sleeve 14 at least partially received within the housing 16, and the piston 22 at least partially received within the sleeve 14, with the piston 22 and the sleeve 14 defining the chamber 28. As described above, the piston 22 has a first position where the chamber 28 has a first volume and a second position where the chamber 28 has a second volume, where the first volume is larger than the second volume. The sleeve 14 has a first rotational position where the inlet port 30 is in fluid communication with the chamber 28, a second rotational position where the outlet port 32 is in fluid communication with the chamber 28, and a third rotational position where the inlet port 30 and outlet port 32 are isolated from the chamber 28. The metering pump 10 also includes the interlock 70 having an elastomeric member 72 positioned on one of the sleeve 14 and the housing 16 and a protrusion 74 positioned on the other of the sleeve 14 and the housing 16. Engagement between the elastomeric member 72 and the protrusion 74 is configured to restrict movement of the sleeve 14 until the sleeve 14 overcomes a predetermined torque value. Accordingly, the interlock 70 is configured to ensure the piston 22 fully completes its linear movement when rotating between the first and second rotational positions. In other words, the predetermined torque value cannot be too high to prevent the metering pump 10 from functioning or too low so that the metering pump 10 prematurely rotates between the first rotational positon and the second rotational position before the piston 22 completes it linear movement.
Referring to
In one aspect or embodiment, the predetermined torque value is 5-15 millinewton meters. In one aspect or embodiment, the predetermined torque value is 5-9 millinewton meters. In a further aspect or embodiment, the predetermine torque value is 5-80 millinewton meters.
In one aspect or embodiment, the interlock 70 is configured to generate a maximum torque at least equal to a difference of torque between maximum and minimum operating pressure of the metering pump 10 while maintaining fluid communication between the chamber 28 and the outlet 32. The maximum torque may be determined by the shape of the elastomeric member 72, the shape of the protrusion 74, and/or the elastic and hyper-elastic material properties of the elastomeric member 72. In some aspects or embodiments, a torque profile provided by the interlock 70 may be symmetric when the sleeve 14 moves between the first and second rotational positions. In some aspects or embodiments, a maximum torque provided by the interlock 70 is smaller when the sleeve 14 is moved from the first rotational position to the second rotational position than when the sleeve 14 is moved from the second rotational position to the first rotational position.
Referring again to
The interlock 70 of
Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
