Medicine vaporizer with crimped conductive pins

A medicine vaporizer for an inhaler includes a metal louver. The metal louver has a first end and an opposing second end, and defines a louver thickness. The medicine vaporizer also includes first and second electrically conductive pins that define a pin thickness greater than the louver thickness. The first electrically conductive pin includes a first crimping region that is attached to and crimped over the first end. The second electrically conductive pin includes a second crimping region that is attached to and crimped over the second end.

FIELD OF THE INVENTION

The present invention relates generally to inhalers, and in particular to a medicine vaporizer with crimped conductive pins for an inhaler.

BACKGROUND

Medicinal inhalers can deliver a medicine or drug to the circulatory system of a patient more rapidly than ingestion (e.g. swallowing a pill) or subcutaneous injection (SCI), but typically less rapidly than intravenous injection. Medicinal inhalers are especially rapid in delivering medicines to a patient's lungs, heart, or central nervous system because blood flow from the lungs proceeds directly to the heart and from there to the brain. Moreover, the use of a medicinal inhaler is typically painless and much more convenient (for the patient) than is SCI or intravenous injection, and may reduce the risk of infection and eliminate the risks associated with improper needle disposal. For at least these reasons, inhalation has become a preferred method for patients to self-introduce certain medicines, for example bronchodilators and various psychoactive drugs.

There are several broad types of medicinal inhalers, each type distinguishable from the others by its structural and functional characteristics and by a different set of advantages and disadvantages.

So-called “atomizer” type inhalers disperse liquid particles into an inhaled gas such as air. The inhaled medicine is carried within the liquid, for example the medicine may be in solution with the liquid. Such a delivery method can be suitable for certain medicines that are adequately stable in the liquid, for example medicines that can maintain efficacy in the liquid over long periods. However, many medicines are unsuitable for long term storage in liquid form.

So-called “dry powder” type inhalers are configured to disperse dry solid particles of a medicine into an inhaled gas. Dry powder inhalers have the advantage that the medicine is stored in dry solid form and therefore may retain its efficacy longer. However, the solid particles can be relatively large or irregular in size and shape, adversely affecting the uniformity and depth of drug distribution within the lungs and/or potentially irritating the lungs of the inhaling patient.

So-called “vaporizing” inhalers utilize a heat source to cause rapid sublimation, and/or melting followed by evaporation, of a solid medicine into gaseous form. An example of a vaporizing inhaler is described in U.S. Patent Publication No. 2005/0268911A1 to Cross et al. The patient typically inhales the heated medicinal gas after it is mixed with a cooler diluting gas such as air. Vaporizing inhalers have the advantage that the medicine is stored in solid form (i.e. potentially maintaining efficacy over a longer period of storage) and the inhaled gas is less likely to irritate the lungs of the inhaling patient because the inhaled gas does not include an excessive size or number of solid particles. However, because vaporizing inhalers typically require a rapid but well-controlled temperature rise in the solid medicine, the design of a practical, safe, and low-cost vaporizing inhalers can be a formidable challenge.

Thus, there is a need in the art for an improved vaporizing inhaler design that is suitable for safe and practical use while also being suitable for high-volume manufacture at acceptably low cost.

SUMMARY

A medicine vaporizer for an inhaler includes a metal louver. The metal louver has a first end and an opposing second end, and defines a louver thickness. The medicine vaporizer also includes first and second electrically conductive pins that define a pin thickness greater than the louver thickness. The first electrically conductive pin includes a first crimping region that is attached to and crimped over the first end. The second electrically conductive pin includes a second crimping region that is attached to and crimped over the second end.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1is a perspective view of a medicine vaporizer100capable of incorporating an embodiment of the present invention. The medicine vaporizer100includes twenty-five metal louvers (e.g. metal louver102), each defining a louver thickness. For example, each of the louvers may be fabricated from austenitic stainless steel, and may define a thickness is in the range 5 μM to 100 μM. Each of the metal louvers (e.g.102) has a first end (e.g.104) and an opposing second end (e.g.106).

The medicine vaporizer100ofFIG. 1also includes fifty electrically conductive pins (e.g.110). Each of the electrically conductive pins (e.g.112) defines a pin thickness greater than the thickness of a corresponding metal louver (e.g.102). Each of the electrically conductive pins (e.g.112) includes a material that has a higher electrical conductivity than that of a corresponding metal louver (e.g.102). For example, each of the electrically conductive pins (e.g.110) may be fabricated from copper, and may define a pin thickness in the range 125 μm to 1.3 mm. As shown further inFIGS. 3 and 4, each of the electrically conductive pins (e.g.112) includes a crimping region that is attached to and crimped over one of the ends (e.g.106) of a corresponding metal louvers (e.g.102).

The medicine vaporizer100ofFIG. 1also includes a frame120in contact with the fifty electrically conductive pins (e.g.110). Preferably, the frame120is an injection molded plastic frame that partially encapsulates each of the electrically conductive pins. The frame120serves to hold and maintain the position and spatial orientation of the fifty electrically conductive pins (e.g.110) relative to each other, so as to control the relative position and spatial orientation of the louvers (e.g.102), including to maintain the relative spacing between the louvers (e.g.102). The relative spacing between the louvers (e.g.102) provides air gaps (e.g.122) that ensure electrical isolation of each louver from another. The frame120also serves to maintain the spatial arrangement of the electrically conductive pins (e.g.110) so that they can be aligned with a pattern of corresponding pin receptacles in a printed circuit board (not shown).

FIG. 2is a perspective view of another medicine vaporizer200capable of incorporating an embodiment of the present invention. The medicine vaporizer200includes twenty-five metal louvers (e.g. metal louver202), each defining a louver thickness. For example, each of the louvers may be fabricated from austenitic stainless steel, and may define a thickness is in the range 5 μm to 100 μm. Each of the metal louvers (e.g.202) has a first end (e.g.204) and an opposing second end (e.g.206).

The medicine vaporizer200ofFIG. 2also includes fifty electrically conductive pins (e.g.210). Each of the electrically conductive pins (e.g.212) defines a pin thickness greater than the thickness of a corresponding metal louver (e.g.202). Each of the electrically conductive pins (e.g.212) includes a material that has a higher electrical conductivity than that of a corresponding metal louver (e.g.202). For example, each of the electrically conductive pins (e.g.210) may be fabricated from copper, and may define a pin thickness in the range 125 μm to 1.3 mm. As shown further inFIGS. 3 and 4, each of the electrically conductive pins (e.g.212) includes a crimping region that is attached to and crimped over one of the ends (e.g.206) of a corresponding metal louvers (e.g.202).

The medicine vaporizer200ofFIG. 2also includes a frame220in contact with the fifty electrically conductive pins (e.g.210). Preferably, the frame220is an injection molded plastic frame that partially encapsulates each of the electrically conductive pins. The frame220serves to hold and maintain the position and spatial orientation of the fifty electrically conductive pins (e.g.210) relative to each other, so as to control the relative position and spatial orientation of the louvers (e.g.202), including to maintain the relative spacing between the louvers (e.g.202). The relative spacing between the louvers (e.g.202) provides air gaps (e.g.222) that ensure electrical isolation of each louver from another. The frame220also serves to maintain the spatial arrangement of the electrically conductive pins (e.g.210) so that they can be aligned with a pattern of corresponding pin receptacles in a printed circuit board (not shown).

FIG. 3is a perspective view of a single louver and pin sub-assembly300, according to an exemplary embodiment of the present invention. The louver and pin sub-assembly300includes a metal louver302and two electrically conductive pins310,312. The metal louver302includes a first end304and an opposing second end306and at least one clean surface suitable for at least partial coating by a medicine. The first electrically conductive pin310includes a first crimping region334that is attached to and crimped over the first end304, and the second electrically conductive pin312includes a second crimping region336that is attached to and crimped over the second end306.

In the embodiment ofFIG. 3, the first crimping region334and the first electrically conductive pin310are a single part having material continuity rather than being an assembly of sub-parts. Likewise, the second crimping region336and the second electrically conductive pin312are a single part having material continuity rather than being an assembly of sub-parts. However, it is contemplated that the first and second electrically conductive pins310,312could each be an assembly of sub-parts. Moreover, the first crimping region334may have a material composition that is different from that of the first electrically conductive pin310outside of the crimping region. For example, the first crimping region334may include a crimping region surface that is plated with a dissimilar conductive plating material that later makes contact with the first end304. The same could be true of the second crimping region336and the second end306.

FIGS. 4A-Cdepict various stages of a louver and pin assembly process according to an exemplary embodiment of the present invention.FIG. 4Adepicts an electrically conductive pin400that has been stamped from an electrically conductive sheet (e.g. a copper sheet), and then formed to include a crimping region410. The crimping region410includes a horizontal land420and a vertical flap430. In certain embodiments, the crimping region410is plated with a conductive plating material.

FIG. 4Badditionally depicts a metal louver440that has been stamped from a metal sheet (e.g. a stainless steel sheet) having a thickness less than the electrically conductive sheet from which the pin400was stamped. In certain embodiments, the louver440is also coined to create a region of the louver440that is thinner than the sheet from which it was stamped. Such coining can optionally be accomplished at the same time as the stamping. An end450of the metal louver440shown inFIG. 4Bhas been positioned adjacent to the crimping region410of electrically conductive pin400. Specifically, in the embodiment shown inFIG. 4B, the end450has positioned to rest upon horizontal land420.

Next, as shown inFIG. 4C, a crimping force460is brought to bear upon the vertical flap430of the conductive pin400, bending it over the end450of the metal louver440. The crimping force460thusly crimps the crimping region410over the450. In certain embodiments, the crimping region410is subsequently staked to enhance the connection between the metal louver440and the electrically conductive pin400.

In an alternative embodiment the crimped connections are further improved by employing materials or material coatings that form metal-metal bonds across the crimp interface. Such a strategy can decrease the mean and/or variability of electrical resistance across the crimp connection. Metal-metal bonding may also improve the mechanical strength of the crimp connection.

Several methods can be used to obtain a metal-metal bond. One such method employs the use of a solder on the regions to be bonded. For example, a solder material can be plated to the surface of horizontal land420and/or a contacting surface of the metal louver440inFIG. 4. The plating can be done using well established methods including continuous and batch type processing, and may optionally use a mask to preclude solder plating on non-contact surfaces. The plating material may be selected from a wide range of compositions, for example 85% Sn, 15% Pb; pure Sn; 95.5% Sn, 4.0% Ag, 0.5% Cu, as well as other material compositions fabricated from In, Sb, Sn, Pb, Cu, and other elements. The plating thickness may range from 0.2 to 50 microns, with the optimum thickness dependant on the condition of the substrate surface and component level factors including fit. Following plating of the components, the assembly is crimped and subsequently heated to form the solder bond.

Solder materials can be remelted and reflowed after bonding. Other approaches can also be employed to affect a metal-metal bond, including metal combinations that allow transient liquid phase (TLP) bonding. Via diffusion at a single temperature, TLP bonding allows the formation of a liquid metal that wets the surfaces to be bonded and then solidifies. Unlike the use of solder, TLP bonds cannot be remelted or reflowed, but are generally more robust and may offer greater mechanical strength. When selecting materials for metal-to-metal bonding, one consideration is that the melting temperature of the material be low enough to facilitate bonding, yet high enough so that subsequent heating associated with use of the inhaler (i.e. medicinal sublimation) does not re-melt the metal-to-metal bond material.

For example, copper and stainless steel components may be TLP bonded after one or both interfacing surfaces are plated with a suitable bonding material (e.g. Mg, Au, Ag, Cu, Ni, Be, etc, and/or combination thereof). The plating methods are similar to those used for solder deposition. As an alternative to plating, a thin metal foil may be placed between bonding surfaces. Following metal deposition or placement, the junction is heated to induce the TLP mechanism.

Both solder bonding and TLP bonding can reduce variation in electrical resistance via the formation of a metal meniscus to bridge separations (if any) at the crimped interface, making the effective length of contact between the surfaces more repeatable.

Coating with a soft metal such as gold prior to crimping can also decrease the electrical resistance across the junction. The soft metal conforms to surface asperities and increases the effective contact area of mating surfaces. The resistance to corrosion offered by gold also improves the reliability of the junction. Other metals that can be used in this way include, but are not limited to, silver, platinum, indium, and various alloys.

Preferably, all of the electrically conductive pins used in the medicine vaporizer are formed at the same time to enhance the speed and economy of the medicinal vaporizer fabrication process. Also, the crimping regions of the two electrically conductive pins that are disposed adjacent the two ends of each louver are preferably crimped at the same time or in immediate sequence to more efficiently utilizes the period during which tools must hold the components in desired relative positions. In certain embodiments, attaching the metal louvers to the conductive pins by crimping, rather than by a prior art method, may reduce contamination and heating, and may render the medicine vaporizer fabrication more economical and better suitable for high volume manufacture.

Either before or after the crimping depicted inFIGS. 4A-C, a plastic frame may be injection molded to be in contact with the electrically conductive pins. For example, a plastic frame may be injection molded to partially encapsulate all of the electrically conductive pins. In certain embodiments, attaching the metal louvers to the conductive pins by crimping enables such attachment to be accomplished after molding the plastic frame. The crimping depicted inFIGS. 4A-Cis preferably but not necessarily accomplished after molding the plastic frame so that the thinner and more delicate metal louvers are held with more stability after attachment to the conductive pins and are therefore better protected from subsequent handling damage during the remainder of the inhaler fabrication process.

In the foregoing specification, the invention is described with reference to specific exemplary embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. It is contemplated that various features and aspects of the above-described invention may be used individually or jointly and possibly in an environment or application beyond those described herein. The specification and drawings are, accordingly, to be regarded as illustrative and exemplary rather than restrictive. The terms “comprising,” “including,” and “having,” as used herein are intended to be read as open-ended terms.