MEDICAL ADMINISTRATION DEVICE WITH AXIALLY EXPANDABLE DRIVE MEMBER

Abstract

A medical delivery device for advancing a piston within a medication container to dispense medication. A support structure supports the container and a drive assembly that advances the piston. The drive assembly includes a retractable and extendable drive belt. The retracted belt defines a spiral, and the extended belt defines a helix. The drive belt can be incrementally moved between the retracted spiral and extended helical configurations. A mechanical mechanism rotates the drive belt to selectively extend and retract it. A drive member with a helical ramp is applied to a proximal edge of the drive belt where it transitions between a spiral and a helix. A support member at the distal end of the drive belt exerts an axial force on the piston when the belt is extended.

Description

The present invention provides a compact and easily transportable medical delivery device. The invention comprises, in one embodiment, a medical delivery device for use with a drug container. The drug container has a container body that holds the drug, defines an outlet, and further includes a piston disposed within the container body, whereby advancement of the piston within the container body expels the drug through the outlet. The delivery device includes a support structure adapted to support the drug container and a drive assembly supported on the support structure and adapted to advance the piston within the container body. The drive assembly includes a drive belt having a distal edge section and a proximal edge section.The drive belt has a retracted and an extended configuration. In the retracted configuration, the retracted portion of the drive belt defines a spiral, and in the extended configuration, the extended portion defines a helix. The drive belt can be moved and extended between these configurations, and its movement from the retracted to the extended configuration defines a drive axis. A mechanical drive is coupled to operate the drive belt and rotates it around the drive axis. Rotation of the drive belt in one direction extends it, and rotation in the opposite direction retracts it.A driving member is arranged to operate between the support structure and the drive belt and is applied with at least a portion of its proximal edge section when the drive belt is at least partially extended. A support member is supported on the drive belt near a distal end of the drive belt. The support member is adapted to exert an axial force on the piston when the drive belt is extended. The axial force exerted by the support member on the piston is transmitted at least partially to the support structure through the drug container. When an axial compressive load is exerted on the drive belt, the axial compressive load is transmitted at least partially to the support structure through the driving member. In some embodiments, the support structure defines a housing adapted to be held in a human hand. In such embodiments, the drug container may have a storage volume of at least 3 mL, with the support structure defining an axial length of no more than 110 mm. The support structure may even define an axial length of no more than 100 mm. In some embodiments of the delivery device, the drive member is fixed to rotate relative to the support structure and defines a helical ramp that engages with the proximal edge section of the drive belt. When the drive belt rotates in the first direction, a transition portion of the drive belt engages the helical ramp, transitioning from the retracted to the extended configuration. When the drive belt rotates in the second direction, the transition portion of the drive belt engaging the helical ramp transitions from the extended to the retracted configuration. In such embodiments, the delivery device may further include a belt support member that surrounds the drive member and exerts an inward radial support force on the drive belt near the helical ramp.The belt support member may take the form of a plurality of rollers engageable with the drive belt, wherein the plurality of rollers exerts an inward radial force and polarizes the drive belt on the helical ramp of the drive member as the drive belt rotates. In those embodiments that include a helical ramp, the retracted portion of the drive belt adjacent to the helical ramp defines a radius larger than the radius of the helical ramp. In some versions of the delivery device, the support member includes a rotating bracket that allows relative rotational movement between the drive belt and the piston around the drive axis. This rotating bracket may take the form of a jewelry stand. The administration device may include, in some embodiments, a drive belt that defines a plurality of gear teeth that can be engaged with the mechanical drive, so that the mechanical drive can rotate the drive belt and thus transmit a rotational force through the plurality of gear teeth. In some drive belt configurations, the extended portion of the drive belt may have a proximal edge section that is directly coupled to an adjacent portion of the distal edge section. In such configurations, one of the proximal and distal edge sections may define a flange that extends radially to directly couple to the other proximal and distal edge section. In such configurations, it is also possible for one of the proximal and distal edge sections to define a plurality of projections and for the other proximal and distal edge section to define a plurality of cooperating recesses. The administration device may have a drive belt which is a one-piece belt in which all axial forces transferred between the support member and the drive member are transferred by the one-piece belt system when the drive belt is at least partially extended. In some embodiments, the delivery device also includes a cylindrical reel in which the retracted portion of the drive belt is stored. In these embodiments, the reel may be arranged to rotate on the drive member. In embodiments that include a reel, for the retracted portion of the drive belt disposed within the reel, the drive belt may be configured such that a surface of the distal edge of the drive belt lies in a first plane oriented perpendicular to the drive axis, and the surface of the proximal edge of the drive belt lies in a second plane oriented perpendicular to the drive axis. In some versions of the delivery device, the mechanical drive includes a battery-powered motor. In some delivery device configurations, the proximal edge section defines a proximal edge surface, and the distal edge section defines a distal edge surface. The proximal edge surface defines a first axially oriented longitudinal portion and a second axially oriented longitudinal portion. The distal edge surface defines a third axially oriented longitudinal portion and a fourth axially oriented longitudinal portion. In the extended portion of the drive belt that defines a helix, the proximal edge section of the belt engages with an adjacent portion of the distal edge section, with the second longitudinal portion. QC / ynn / eznz / B / Yi of the proximal edge surface coupled with the third longitudinal portion on the distal edge surface, and wherein the first longitudinal portion of the proximal edge surface and the fourth longitudinal portion of the distal edge surface extend radially outward in opposite directions. And, in such modalities, the driving member is coupled with the first longitudinal portion of the proximal edge surface. The driving member can be applied to the first longitudinal portion of the proximal edge surface in a transition portion of the drive belt disposed between the retracted portion and the extended portion of the drive belt. The invention comprises, in another embodiment, a medical delivery device for use with a drug container having a container body that holds the drug and defines an outlet. The drug container further includes a piston disposed within the container body, where advancement of the piston within the container body expels the drug through the outlet. The delivery device includes a support structure adapted to support the drug container; and a drive assembly supported on the support structure and adapted to advance the piston within the container body. The drive assembly includes a drive belt having a distal edge section defining a distal edge surface and a proximal edge section defining a proximal edge surface.The drive belt has a retracted and an extended configuration. In the retracted configuration, the retracted portion of the drive belt defines a spiral, and in the extended configuration, the extended portion defines a helix. The drive belt can be moved and extended between the retracted and extended configurations. This movement of the drive belt from the retracted to the extended configuration defines a drive axis. The proximal edge surface defines a first axially oriented longitudinal portion and a second axially oriented longitudinal portion, while the distal edge surface defines a third axially oriented longitudinal portion and a fourth axially oriented longitudinal portion.In the extended portion of the drive belt that defines a helix, the proximal edge section of the belt is coupled with an adjacent portion of the distal edge section, with the second longitudinal portion of the proximal edge surface coupled with the third longitudinal portion of the distal edge surface, and wherein the first longitudinal portion of the proximal edge surface and the fourth longitudinal portion of the distal edge surface extend radially outward in opposite directions. A mechanical drive is coupled to operate the drive belt and selectively rotate the drive belt around the drive axis, where rotation of the drive belt in a first direction extends the drive belt and rotation of the drive belt in a second, opposite direction retracts the drive belt.A drive member is arranged to operate between the support structure and the drive belt. The drive member is coupled to the first longitudinal portion of the proximal edge surface. A support member holds the drive belt near a distal end of the drive belt. The support member is adapted to transfer an axial force to the drive belt when the drive belt is extended. In some modalities, the fourth longitudinal portion of the distal border surface projects radially outwards and the first longitudinal portion of the proximal border surface projects radially inwards. In some embodiments, the driving member includes a helical thread that can engage with the first longitudinal portion of the proximal surface. In one such embodiment, the helical thread can extend more than 360 degrees around the drive axis. In a modality with a drive member having a helical thread, the device can be configured so that the fourth longitudinal portion of the distal edge surface protrudes radially outward and the first longitudinal portion of the proximal edge surface protrudes radially inward, and the device delivery further includes a belt support member circumscribing the drive belt, wherein the belt support member defines a second helical thread engageable with the fourth longitudinal portion of the distal edge surface. In one embodiment of this type, which has a second helical thread, the helical thread of the drive member can extend more than 360 degrees around the drive axis. In other embodiments, the second helical thread can extend more than 360 degrees around the drive axis with the belt support member circumscribing the drive belt close to the drive member. In some configurations, when the drive belt is unwound and laid flat, it forms an arc. In such a configuration, the belt can be arranged so that, when unwound and laid flat, the proximal edge section is positioned radially inward of the distal edge section, and when the belt forms a helix, the fourth longitudinal portion of the distal edge surface projects radially outward, and the first longitudinal portion of the proximal edge surface projects radially inward. In some embodiments, one of the proximal and distal edge sections defines a plurality of pegs and the other of the proximal and distal edge sections defines a plurality of holes, wherein, in the extended portion of the drive belt that defines a helix, the coupling of the proximal edge section of the belt with the adjacent portion of the distal edge section includes the coupling of the pegs with the holes. In a configuration with pins and holes, the drive belt may define a plurality of gear teeth that mesh with the mechanical drive, allowing the mechanical drive to engage and rotate the drive belt, thus transmitting a rotational force through the plurality of gear teeth. For example, the mechanical drive may include a worm gear that meshes with the plurality of gear teeth. In a configuration where the belt includes pins, holes, and gear teeth, the drive belt can be configured so that it defines the first and second principal surfaces on opposite sides of the drive belt, and the plurality of pins, the plurality of holes, and all the gear teeth are expressed on the first principal surface of the drive belt, so that the plurality of pins, the plurality of holes, and the gear teeth are adapted to be machined from the side of the first principal surface, and where the second principal surface defines a flat surface.In such a modality, the drive belt can be a one-piece unit belt and all axial forces transferred between the support member and the drive member when the drive belt is at least partially extended are transferred by the unit belt and the outermost portions of the first and second principal surfaces define planes that are parallel to each other and the distance between the planes defined by the first and second principal surfaces defines the maximum thickness of the drive belt. In some embodiments, the delivery device may also include a reel that is rotatable with respect to the drive member with the retracted portion of the drive belt being stored on the reel. It is noted that several different features of the delivery device are described herein, and these features can be combined in various configurations. Although several different combinations of such features are described in the present invention, the person skilled in the art will realize that additional combinations not explicitly described herein are also possible, enabled by this description, and within the scope of this application. Brief description of the figures The aforementioned features and other features of this invention, and the means of achieving them, will become more evident and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying figures, where: FIGURE 1A is a side view of a first modality of a delivery device. FIGURE 1B is an extreme view of the first modality. FIGURE 1C is another extreme view of the first modality. FIGURE 1D is a side view of the first modality with the cover removed and a needle assembly attached. FIGURE 1E is an extreme view of the modality in FIGURE 1D. FIGURE 1F is a perspective view of the first modality. FIGURE 2A is a side view of a previous technique delivery device. FIGURE 2B is an extreme view of the prior art device. FIGURE 2C is another extreme view of the prior art device. FIGURE 2D is a side view of the prior art device with the cap removed and a needle assembly attached. FIGURE 2E is an extreme view of the prior art device in FIGURE 2D. FIGURE 2F is a perspective view of the prior art device. FIGURE 3A is a side view of a second modality of a delivery device. FIGURE 3B is an extreme view of the second modality. FIGURE 3C is another extreme view of the second modality. FIGURE 27 is a cross-sectional view taken along line 27-27 of FIGURE 26 and also showing the belt support member. FIGURE 28 is a side view of the version in FIGURE 21 with the casing removed. FIGURE 29 is an extreme view of the FIGURE 21 modality with the casing removed. FIGURE 30 is a side view of another modality with the casing removed. FIGURE 31 is an extreme view of the FIGURE 30 modality with the casing removed. FIGURE 32 is a perspective view of the version in FIGURE 30 with the casing removed. FIGURE 33 is an orderly exploded view of the version in FIGURE 30 without the casing. The corresponding reference characters indicate corresponding parts along the various views. Although the example set forth herein illustrates one embodiment of the invention, the embodiment described below is not intended to be exhaustive and should not be interpreted as limiting the scope of the invention to the precise embodiment described. Detailed description of the invention A first embodiment of a compact medical delivery device 20 is shown in Figures 1A-1F, while a second embodiment of a compact medical delivery device 20A is illustrated in Figures 3A-3F. A medical delivery device 21 of the conventional prior art is shown in Figures 2A-2F. The device 21 illustrated in Figures 2A-2F is a commercially available Kwikpen injector from Eli Lilly and Company, headquartered in Indianapolis, Indiana, and is approximately 145 mm long. As can be seen in a comparison of Figures 1A, 2A, and 3A, the compact medical delivery devices 20 and 20A are considerably shorter in length than the conventional device 21. However, the conventional device 21 is thinner than the compact devices 20 and 20A, as can be seen with reference to Figures 1B, 1C, 2B, 2C, 3B, and 3C. The medical delivery device 20 receives a drug container 22. As schematically represented in Figure 17, the drug container 22 includes a container body 24 that holds a drug 25, for example, insulin, within its cylindrical barrel. A piston 26 is disposed within the body 24, and the advancement of the piston 26 within the container body 24 expels the drug 25 through the outlet 28. In the illustrated embodiment, the outlet 28 is an injection needle having one end that pierces a septum of the container and an opposite end that can be inserted into a patient to inject the drug 25. Device 20 also includes a support structure 30 adapted to support the drug container 22. The support structure 30 also functions as a device housing in the illustrated form and is also referred to herein as the housing. The housing 30 also supports a drive assembly 32 for advancing the piston 26 and is adapted for handholding. Device 20 and Device 20A are generally similar but have different housings, with the housing 30A of Device 20A being slightly larger than the housing 30. Both housings 30 and 30A include a removable cap 31 and 31A that can be attached to and released from the cap / needle outlet 28 when the device is not in use. Figures 1D and 3D illustrate devices 20 and 20A with caps 30 and 30A removed, while Figures 1A and 3A show caps 31 and 31A installed on housings 30 and 30A. As can be seen in Figures 1D and 3D, caps 30 and 30A are used to cover a standard needle, which also has an internal, cylindrical, removable needle shield 29. As can be seen with reference to Figures 3A and 3D, removing the cap 31A exposes almost the entire length of the container body 24. Generally, the container body 24 will be formed from glass or another transparent material. By exposing this length of the container body 24, the user can visually determine the amount of drug 25 remaining in the cartridge body 24. In contrast, the housing 30 only exposes the end of the drug container 22 near the outlet 28 and provides an open slot 42 in the housing 30 to allow the user to visually determine the amount of drug 25 remaining in the container body 24. A transparent material can be used to form a window instead of an open slot 42 to allow for such visual inspection. Housing 30 includes a control knob 44 for adjusting a dosage, a button 45 for initiating an injection, and an electronic display 46 located at the end of housing 30. For example, knob 44 can be rotated to adjust the injection dosage, and the center button 45 can be depressed to initiate the injection process. Housing 30A includes controls 44A and an electronic display 46A on the side of housing 30A. Controls 44A are used to set an injection dosage, while control knob 45A at the end of housing 30A is used to initiate the injection procedure. Although the illustrated models have actuators located at the end of the housing to initiate an injection, other locations on the housing can also be used for this function.For example, the thicker casing compared to conventional pens may cause some people to grip the device differently, and an actuator that initiates the injection procedure may be deployed on the side of the casing. The patient's grip may also depend on where the injection will be administered on the patient's body, and in some modalities, it may also be desirable to include multiple actuators in the casing to facilitate various gripping scenarios. The drug container 22 has a storage volume of at least 3 mL and is shown in the form of a conventional drug cartridge. The support structure 30 can define an axial length of no more than 110 mm, or even an axial length of no more than 100 mm. The axial length of support structures 30 and 30A is indicated by reference numbers 48 and 48A, respectively, in Figures 1A and 3A. As is evident from Figures 1A and 3A, the axial length of the support structure referenced herein includes the removable caps. In the illustrated embodiments, the crowned axial lengths 48 and 48A are both 105 mm. In the illustrated embodiment, the axial lengths 48 and 48A of devices 20 and 20A are less than twice the axial length 49 of container 22 (excluding needle 28).A standard 3 mL drug cartridge used for insulin has an axial length of 64 mm and a plunger stroke of approximately 43 mm. The use of a drive assembly 32 having a drive belt 40 allows devices 20 and 20A to have relatively short axial lengths 48 and 48A. Figure 17 provides a schematic overview of device 20 showing how the container 22 is positioned on the support structure 30 relative to the drive assembly 32. The drive assembly 32 includes a mechanical drive 38 coupled with drive belt 40. The drive belt 40 can extend from a retracted to an extended configuration. With a drug container 22 installed in device 20, moving the drive belt from a retracted to an extended configuration extends the drive belt 40, causing the piston 26 to advance and the drug to be discharged through outlet 28. Selective rotation of the drive belt 40 by means of the mechanical drive 38 causes retraction or extension of the drive belt 40. In the illustrated embodiment, the mechanical drive 38 includes a DC electric motor 34 and a battery 36, for example, a single AAA battery or rechargeable lithium-ion cell, to power the motor 34. An alternative arrangement could employ an external electrical power source or an alternative form of torque supply. For example, a torsion spring or other arrangement could be manually tensioned with selective release of that tension providing the torque required to drive the operation of the drive assembly 32. The mechanical drive 38 selectively engages with the drive belt to rotate the belt 40 around a drive axis 50 in either direction of rotation. In one direction of rotation, it causes the drive belt 40 to extend axially; in the opposite direction of rotation, it causes the drive belt 40 to retract. The rotation of the drive belt 40 shifts the belt between spiral and helical configurations. When the drive belt 40 is fully extended, most, if not all, of it will be in a helical configuration. When the drive belt 40 is fully retracted, most, if not all, of it will be in a spiral configuration.In most axial positions, an extended portion 52 of the drive belt 40 will define a helix, while a retracted portion 54 of the drive belt 40 will define a spiral. Rotation of the drive belt 40 causes the belt to shift and increment between these two configurations. Figures 5-11 provide detailed views of the drive belt 40. Figure 6 illustrates the belt 40 in a configuration where it is partially extended. In Figure 6, the retracted portion 54 defines a spiral, while the extended portion 52 defines a helix. In the retracted portion 54, the axial end surface of the distal edge section 56 of the belt 40 for each of the spiral windings lies in a common plane 110. Similarly, the axial end surface of the proximal edge section 58 of each of the spiral windings also lies in a common plane 112. This spiral arrangement allows the retracted portion 54 of the belt 40 to be stored in a minimal axial space that is approximately equal to the width of the belt 40.In the extended portion 52 of the drive belt 40, the proximal edge section 56 fits directly into an adjacent portion of the distal edge section 58. Figures 6 and 11 show an extended helical portion 52 with mated edges, while Figures 5 and 7 show an exploded view of the drive belt 40. Figures 5 and 7 are provided to explain and show the details of the belt 40. In use, the drive belt 40 would not assume the exploded configuration shown in Figures 5 and 7. One of the proximal 58 and distal 56 edge sections of the strip 40 defines a radially extending flange 60 that mates with the other proximal 58 and distal 56 edge sections. As shown in Figure 8, in the illustrated configuration, the distal edge section 56 includes a radially extending flange 60, where the illustrated flange 60 extends radially inward. The flange 60 includes an axially oriented surface 62 that is generally perpendicular to the axis 50 and is applied to the opposite proximal edge 58 to allow the transfer of axial compressive forces. The strip 40 also provides for the transfer of torsional forces. One of the proximal 58 and distal 56 edge sections of the strip 40 defines a plurality of projections 64 with the other proximal 58 and distal 56 edge sections, which define a plurality of cooperating recesses 66.The interposition of projections 64 with recesses 66 enables torque transfer and helps to keep the proximal edge sections 58 and distal edge sections 56 locked together as the tape 40 is rotated. As can be seen in Figures 8 and 9, in the illustrated configuration, the distal edge section 56 defines the plurality of recesses 66, and the proximal edge section 58 defines the plurality of projections 64. It is observed that it is the coupling of the sidewall surfaces 68 of recesses 66 with sidewall surfaces 70 of projections 64 that enables torque transfer. The sidewall surfaces 68 and 70 define flat surfaces that are substantially and radially oriented with respect to the axis 50. This radial orientation of the mating sidewall surfaces resists shear forces along the joint and, therefore, torsion in the column formed by the extended tape 40.Several other arrangements and configurations of the cooperating projections 64 and the rebates 66 can be used. For example, the rebates 66 could form openings that extend through the full thickness of the tape 40. As a result of the resistance to shear forces along the joint formed by the mating edges, the resulting column resists torsional loads by preventing one end from rotating relative to the opposite end. It also resists twisting and unwinding of the column formed by the extended portion 52 of the tape 40. The distal edge sections 56 and proximal edge sections 58 also include radially extending tabs 72 and 74, respectively. Tab 72 on the distal edge section 56 extends radially inward, while tab 74 on the proximal edge section 58 extends radially outward. When the distal edge sections 56 and proximal edge sections 58 are mated, the radially outward-extending tab 74 seats in the groove 76 defined by the flange 60 and tab 72. The mating of tabs 72 and 74 provides resistance to axially acting tensile forces and prevents the distal edge sections 56 and proximal edge sections 58 from separating axially when subjected to axially acting tensile forces. When deployed, tape 40 forms a helix to create a rigid, interconnected cylindrical column. The interlocking of distal edge sections 56 and proximal edge sections 58 provides the column with axial and torsional stiffness and strength, as previously described. Tape edge sections 56 and 58 are mechanically coupled to each other so they can be disassembled and reattached. The deployment process, discussed below, is continuous, enabling a smooth and precise injection process. The column formed by the extended portion 52 of the belt 40 acts as a continuous tubular structure and will primarily support the axial compressive loads corresponding to the force required to eject the drug from the container 22. It will also carry some torsional loads generated by the rotation of the belt 40 as it extends and retracts. Although axial tensile loads are not generally applied to the belt 40, the use of interlocking tabs 72 and 74 provides resistance to axial tensile loads, thus preventing the hooked edges of the belt 40 from separating axially during use and improving the reliability of the belt 40. The drive belt 40 also defines a plurality of gear teeth 76 that can mesh with the mechanical drive 38, allowing the mechanical drive 38 to rotate the drive belt 40 by transmitting a rotational force through the plurality of gear teeth 76. As can be seen in Figures 8 and 9, the gear teeth 76 are arranged on the inwardly oriented radial surface of the belt 40. While the gear teeth 76 are arranged on the inner face of the belt 40, an alternative arrangement can use gear teeth on the radially outer surface of the belt 40. Figure 10 illustrates a set of gear teeth 78 on the outer surface of the belt 40, which are formed by a series of recesses. Internal or external gear teeth 76 can be used to rotate the belt 40.Other variations are also possible; for example, gear teeth could be used on the proximal edge of belt 40, or internal and external gear teeth could be used on the same belt. The coupling and rotation of belt 40 by means of the mechanical drive 38 are explained in more detail below. The illustrated embodiments of the 40 drive belt utilize a flexible polymeric belt that has been machined to define the various belt characteristics. Nylon, polypropylene, and high-density polyethylene are examples of suitable polymeric materials that can be used to form the 40 belt. While the illustrated embodiments are machined, alternative embodiments could use a molding process to form a 40 polymeric belt with all its edge characteristics. Molding the belt into a flat arrangement and then winding it into a spiral configuration is anticipated to be the most efficient manufacturing method for forming a 40 belt. Other materials can also be used to form tape 40. For example, a thin strip of metal could be used to form tape 40. Photographic etching, laser etching, or other suitable micro-machining methods could be used to form the individual features of tape 40. Alternatively, a metallic tape could be formed by diffusion bonding two layers of medium QC / ynn / eznz / e / Yi thickness instead of using a single strip of metal. Still other tape formulations could take the form of an overmolded metal strip. The metal strip would be provided with the distal edge features, and the overmolded plastic portion of the tape would form the proximal edge features. This approach combines the desirable stiffness, elasticity, and creep resistance of metal with the low friction and ease of manufacturing for forming small features in molded plastic. For all Tape 40 formulations, it is desirable that the Tape 40 be flexible so that it can extend and retract, and undergo concomitant elastic stresses, without permanent deformation. The distal end of belt 40 must exert axial forces on piston 26. To allow this force transfer, a support member 80 is supported on the drive belt 40 near the distal end 81 of the drive belt 40 and is adapted to exert an axial force on piston 26. The column formed by belt 40 will rotate as it extends; however, piston 26 in the housing 22 does not rotate. A swivel support 82 is provided at the distal end 81 of belt 40 to account for the relative rotational movement and to allow relative rotational movement between the drive belt 40 and piston 26 about the drive axis 50. In the illustrated embodiment, the swivel support 82 is a jewel bearing located in the support member 80.In the illustrated embodiment, the support member 80 is shown as an integral part of the drive belt 40, but the two can also be separate parts with a suitable joint between them. As can be seen in Figure 10, a transfer member 84 acts on the piston 26 or another intermediate part and includes a projecting member 86 that rotates within the support 82. The transfer member 84 pushes and advances the piston 26 and does not rotate relative to the piston 26 as the belt 40 advances. As the belt 40 advances and rotates relative to the piston 26, the projecting member 86 rotates within the rotating support 82. Since the loads are predominantly axial and it is desired to minimize friction losses, the revolutionary joint at this location can be a low-friction jewel bearing; however, other arrangements that allow relative rotation of the belt 40 and the piston 26 can also be used. A driving member 88 (Figure 2) is arranged to operate between the support structure 30 and the drive belt 40. The driving member 88 is coupled to a portion of the proximal edge 58 of the belt 40 when the drive belt 40 is at least partially extended. More specifically, the driving member 88 is applied to the belt 40 where it transitions between a spiral and a helical configuration and also supports axial compressive forces acting on the belt 40. In the illustrated embodiment, the drive belt 40 is a unit belt, and the forces transferred between the support member 80 and the driving member 88, when the drive belt 40 is at least partially extended, are transferred by the unit belt 40.The axial compression load created by the piston support 26 is transmitted to the support structure 30 via a surface support 91 at the axial end of the drive member 88 opposite the ramp 90. Thus, it is observed that part of the axial compression force acting on the belt 40 will act on the drug in the container 22, causing the drug to be ejected through the outlet 28. It is also observed that the axial force exerted by the transfer member 84 on the piston is transmitted at least partially to the support structure 30 through the drug container 22; otherwise, the container 22 would simply move axially along with the extended belt 40. If the container 22 is held within the device 20 and 20A by a friction fit within the support structure 30, this friction fit may be sufficient to hold the container 22 in place and absorb the axial compressive forces acting on the container. Alternatively, a structural retainer could be used to retain the container 22 in the support structure 30. Figure 18 schematically represents how the shoulder surface 128 of the container 22 could be engaged by sliding a retainer with the bearing surface 130 mating with the shoulder 128.The compressive forces would be transferred from shoulder 128 to surface 130 and, therefore, to the retainer that is part of support structure 30. The driving member 88 is fixed to rotate relative to the housing 30 and defines a helical ramp 90 that is applied to the proximal edge 58 of the belt 40. Axial compressive forces are transferred between the belt 40 and the driving member 88 on the helical ramp 90. The helical ramp 90 also guides the transition of the belt 40 between its spiral and helical configurations. When the drive belt rotates in a first direction so that the proximal edge 58 engaged with the ramp 90 slides upwards and in a distal direction, a transition portion 53 of the belt 40 that is engaged with the helical ramp 90 is guided by the ramp 90 in a helical arrangement and transitions from the retracted (spiral) configuration 54 to the extended (spiral) configuration 52. Similarly, when the belt 40 rotates in a second opposite direction, the transition portion 53 of the belt 40 that engages helically with the ramp 90 slides downwards along the ramp 90 and transitions from the extended (spiral) configuration 52 to the retracted (spiral) configuration 54. Due to the limited contact area between the proximal edge section 58 and the ramp 90, the friction-resistant sliding motion is relatively small. To limit additional friction and sliding resistance along the ramp 90, the driving member 88 can be formed from a lubricating polymeric material such as acetal. The proximal edge section 58 can form a continuous surface and avoid recesses or interruptions in the portion of the proximal edge section 58 that mates with the ramp 90 to prevent the increased resistance and greater wear that such irregular surfaces can cause. Alternative drive support surfaces may also be used. For example, instead of a sliding surface, small rollers could be arranged in a helical pattern along the outer perimeter of the drive member. Due to the small scale and low forces typically anticipated when using Tape 40 to inject a drug, the increased manufacturing difficulties and expenses that these rollers would entail are generally not warranted. An axially extending wall 92 is located radially at the inner edge of the helical ramp 90 and extends distally. The wall 92 prevents the proximal edge section 58 from being deflected radially inward to disengage from the ramp 90 by the belt support member 100. The belt support member 100 surrounds the drive member 88 and exerts a radially inward support force on the drive belt 40 adjacent to the helical ramp 90. The belt support member 100 includes a sleeve 102 surrounding the drive member 88 and a plurality of rollers 94 mounted within the sleeve 102. The rollers 94 can engage with the drive belt 40 and exert a radially inward force and a biased drive belt 40 on the helical ramp 90 as the drive belt 40 is rotated.The rollers 94 include a cylindrical disc 96 that engages with the belt 40 and the shaft heels 98 that extend from opposite sides of the disc 96 and are mounted to rotate on the inner surface of the sleeve 102. Tape 40 is fed onto the helical ramp 90 from the retracted portion 54 of tape 40, which is stored within the coil 104 in a spiral configuration, as shown in Figure 16. The proximal end 106 of tape 40 is secured to the coil 104, and when tape 40 rotates, the coil 104 rotates with it. In the polished configuration, the coil 104 is a cylindrical storage coil and is mounted to rotate on the drive member 88. In the polished configuration, the coil 104 includes an axially extending groove 108 in which the proximal end 106 of tape 40 is secured. Various other methods may also be used to secure the proximal end 106 to the coil 104. Both tape 40 and coil 106 rotate about the axis 50. As can be seen in Figure 16, for the retracted portion 54 of the drive belt 40 arranged within the reel 104, the axial end surface of the distal edge section 56 of the drive belt 40 lies in a first plane 110 oriented perpendicular to the drive axis 50, and the axial end surface of the proximal edge section 58 of the drive belt 40 lies in a second plane 112 oriented perpendicular to the drive axis 50. This spiral configuration allows the belt 40 to be stored in a minimal amount of space and is particularly useful for reducing the axial length of the storage space required for storing the belt 40. The distance between planes 110 and 112 is equivalent to the width of the belt 40, i.e., the shortest distance between the opposite axial end surfaces defined by the distal and proximal edge sections 56 and 58 of the belt 40. As can also be seen in Figure 16, the retracted portion 54 of the tape 40 fills the storage reel 104 from the radially outermost location within the reel 104 inwards, with the innermost portions of the stored tape 40 defining an even larger radius than the radius of the helical ramp 90. This facilitates the movement of the tape 40 from the stored spiral configuration of the retracted portion 54 to the extended helical configuration of the extended portion 52 by coupling the tape 40 with the support member of the tape 100. It is desirable that tape 40 naturally assume a coiled shape with a radius larger than the inner diameter of reel 104, so that tape 40 will expand to conform to the inner surface of reel 104 when stored on it. Some plastic materials tend to sag and assume their stored dimensions. Using a metallic tape or an overmolded metallic tape will minimize the risk of the tape failing to expand and fill the outermost radial portions of reel 104. While the illustrated mode uses a cylindrical storage reel 104 for the tape 40, other alternative modes are also possible. For example, a plurality of buttresses within the housing 30 may be sufficient for some modes, or, if the tape 40 has the appropriate physical properties, it could naturally assume a coiled configuration when uncoupled from an adjacent turn of the tape, thus avoiding the use of a storage reel. The size of the storage reel 104 is chosen to be suitable when the tape 40 is fully retracted. When fully retracted, the tape 40 has a minimum radius that is larger than the radius of the ramp 90, which corresponds to the radius of the extended helical portion 52 of the tape 40. As the tape 40 rotates in a direction that feeds the stored tape 40 from the storage reel 104 onto the helical ramp 90, each additional reel of tape passes from the inside of the storage spiral into the column formed by the extended portion 52. The transition portion 53 of the tape 40 becomes radially smaller as it moves from its stored configuration on the reel 104 toward the ramp 90 and becomes tangent to the helical column formed by the extended portion 52 at the point where the tape 40 joins the helical column of the extended portion 52.As the tape moves radially inward along this helical path, the features along the distal edge section 56 of the transition portion 53 of tape 40 are applied to the features of the proximal edge section 58 of the lowest turn of the extended portion 52 of tape 40. The position where radial placement and engagement of the tape edge occurs remains fixed within the device and is fixed relative to the driving member 88. Distally from this coupling point, the tape is a helical column forming the extended portion 52; proximally from this point of application, the tape relaxes through the helical transition spiral (transition portion 53), into the spiral arrangement (retracted portion 54) contained within the storage reel 104. All reels of tape 40 distal to the coupling location, i.e., the extended portion 52 of tape 40, are held coupled to each other by the tape reel proximally beneath them. At the coupling point, the proximal edge of the tape reel being coupled is still uncoupled and is deflected radially inward by the tape support member 100 so that the applied tape reel does not expand radially outward and fail to couple. Simultaneously, tape 40 must be held in a position surrounding the axis 50. These tasks are accomplished by an external support 100 that surrounds approximately one complete helical reel of tape 40. Relative to this fixed support 100, tape 40 rotates and translates as tape 40 advances (or retracts) along its helical path. As discussed previously, the illustrated embodiment uses a belt bearing member 100 that includes a plurality of rollers 94. In this arrangement, each of the rollers 94 is tangent to the cylinder defined by the belt 40 and inclined at the helix angle. The rollers 94 roll rather than slide along the cylinder defined by the belt 40. The position of the rollers 94 establishes and then maintains the coupling of the belt edge sections 56 and 58 while maintaining the overall helical structure of the coupled belt edges supported both radially and axially. While the described rollers 94 are effective, simpler alternative arrangements may be more suitable. QC / ynn / eznz / B / Yi bearings that can be manufactured more cost-effectively may be suitable for some applications. For example, small ball bearings arranged in a groove similar to a conventional ball bearing or found in a ball screw may be suitable for some applications. A simple bushing formed from a lubricating polymeric material may also be suitable for some applications. Figure 4 provides a partially transparent view of the drive assembly 32, and views of alternative drive assemblies are provided in Figures 14 and 15. In the illustrated embodiments, the drive assembly 32 includes a battery-powered electric motor 34 and a mechanical drive 38. The mechanical drive 38 includes a motor shaft 114 that is driven by the motor 34 and includes a gear arrangement 116 for transferring the torque generated by the motor 34. The transfer of torque from the motor 34 to the belt 40 enables the belt 40 to perform mechanical work, i.e., to rotate and advance the belt 40 to move forward with the piston 26, or, when rotated in the opposite direction, to retract the belt 40 and wind it into a spiral on the reel 104. The small electric motor 34 provides the power to operate the extension and retraction of the belt 40. Motors of this size typically use a mechanical gear reduction. Sensing the angle of the motor shaft can be used to control the advance of the belt 40 and, therefore, the delivered dose. Figures 14 and 15 illustrate two different arrangements by which torque can be transferred from the motor 34 to the belt 40. Various other torque transfer arrangements and modifications to the illustrated arrangements with the drive belt 40 can also be used. In the embodiment of Figure 14, belt 40 includes gear teeth 76 on its inner surface. A gear member 124 having gear teeth 126 meshing with gear teeth 76 is used to rotate belt 40. The gear member 124 includes a shaft (not shown) extending through the opening 93 in the drive member 88. The shaft includes another gear arrangement meshing with a transfer gear member that is also engaged with the gear arrangement 116 on the motor shaft 114, so that torque from the motor 34 is transferred to belt 40. In the internal gear drive arrangement shown in Figure 14, the teeth 76 on the inner wall of the belt 40 mesh with a gear inside the helical column formed by the extended portion 52. As gear 124 rotates, it causes belt 40 to rotate and extend or retract. In the illustrated configuration, the axis of rotation of gear 124 is parallel to axis 50 and slightly offset. This offset arrangement, along with gear 124 having a smaller outer diameter than the inner diameter of belt 40 at the location of gear 124, allows gear 124 to engage belt 40 at only one point rather than along the entire perimeter of gear 124. The gear pitches are selected to establish a conventional mesh engagement.With a spur gear, the internal teeth 76 on belt 40 are angled by the helix angle (relative to the belt edge) to ensure proper meshing. As belt 40 extends (or retracts) as it rotates, the gear teeth slide axially over one another as belt 40 rotates. The drive gear 124 can also have helical teeth if the helical teeth are inclined to match the helix angle of the extended portion 52. In such an application, the teeth of the belt 76 can be perpendicular to the belt edge. Other relative angles between the teeth of gear 76 and the belt edges 56 and 58 are also possible. Various other arrangements are also possible; for example, alternative shaft orientations are possible (e.g., the gear could be arranged to be tangent to the helix). Using an internally positioned gear can be effective. For some applications, however, it presents drawbacks. For example, it will generally require that some mechanical members, such as a gear train to rotate the internal gear 124, be arranged at the axial and proximal end of the driving member 88. This can add additional axial length to the overall device. This arrangement also requires a sufficiently rigid and radial mechanical structure to hold the external belt support member 100 in place. Figure 15 illustrates an embodiment in which belt 40 includes a gear arrangement 78 on its outer surface. In this embodiment, two transfer gear members 118 transfer torque from the motor shaft 114 to belt 40. More specifically, each of the transfer gear members 118 includes a gear arrangement 120 that meshes with the gear arrangement 116 on the shaft 114 and a helical gear 122 engaged with belt 40. The external drive system shown in Figure 15 uses a helical gear 122 entangled with external grooves 78 in the belt 40. The helical gear 122 can be chosen to have a helix angle that matches the helix angle of the extended portion 52 of the belt 40, thereby allowing the grooves 78 to be cut into the belt 40 and arranged perpendicular to the belt edge. Although two helical gears 122 are shown in Figure 15, a single helical gear 122 could be used alternatively. As the gear(s) rotate, the belt is advanced or retracted. The use of an external helical gear mechanism, such as the transfer gear members 118, places the transfer gear member 118 on the side of the belt 40 and therefore does not add axial length to the device. Furthermore, the transfer gear members 118 can reduce the number of rollers 94 because they provide radial support to the belt 40. The polished 22 cartridge is a replaceable cartridge. To facilitate convenient replacement of the 22 cartridge after it is empty, a cartridge retainer can be used. Such retainers are well known in the art and normally use a threaded seal or a bayonet seal; however, other suitable mechanical retaining devices can also be used. Another consideration regarding the replacement of container 22 is to avoid user contact with the extension portion 52 of tape 40. While contact with the extension portion 52 will not necessarily cause damage, rough handling of tape 40 has the potential to impair its operability, for example, by detaching edge sections 56 and 58 from the extended portion 52. QC / ynn / eznz / B / Yi can use various approaches to inhibit or prevent such contact. For example, if the entire length of the extended portion 52 were exposed when the container 22 was removed, a mechanical interlock could be provided so that the tape 40 retracts before the container 22 is removed. If only the distal end of the container 22 is exposed and the extended portion 52 is protected from contact by the housing 30, an electrical interlock could command the retraction of the tape 40 when the removal of the container 22 is detected. It is also noted that although the illustrated modalities discussed in this document use replaceable containers 22 to allow reuse of the devices 20 and 20A-20C, alternative modalities could take the form of pre-filled disposable devices or use a drug container that is reusable and refillable instead of being discarded and replaced. Another embodiment, device 20B, is shown in Figures 21-29. Device 20B is generally similar to devices 20 and 20A but has several modifications. The overall length of device 20B, as shown in Figure 21, is less than 110 mm. Device 20B dispenses medication from a container 22 that has a needle 28. A removable cap 31B covers the needle 28 when device 20B is not in use and has sufficient space to allow the use of an internal needle guard 29. The support structure 30B provides a housing for mounting the drive 32B. A cartridge sleeve 140 receives the container 22 and has an opening 142 through which the needle 28 can be extended. The cartridge sleeve 140 is best seen in Figure 33 and includes a threaded portion 144 adjacent to the opening 142. A locking cap 146 is applied to the threaded portion 144 and is used to secure the needle 28 to the cartridge sleeve 140.A set of rear threads 148 secures the cartridge sleeve 140 to the device. In polished versions, the rear threads 148 engage with corresponding threads on an extension of the tape support member. The polished cartridge sleeve 140 also includes an axially extending opening 150 that functions as a window, allowing the user to view the container 22 to check the amount of medication remaining without removing it. The cartridge sleeve 140 also provides a bearing surface that functions similarly to surface 130 and may consist of an internal shoulder that contacts the tapered portion of the container 22. Various other means may also be used to secure the container 22 within the device. Figure 22 illustrates the main components of drive assembly 32B. Drive assembly 32B includes a DC motor 34B having an output shaft 114B on which a first gear 116B is secured. Gear member 116B engages gear members 120B located on two transfer gears 118B. Gear members 116B and 120B are helical and cross-shaft wrap gears. Helical gears 122B on the transfer gears 118B engage the teeth of gear 78B on the outside of the drive belt 40B to rotate the belt 40B. The helical gear pitch, gear ratio, and pitch of the 78B gear slots on the 40B belt are all selected to work together. In this regard, it is noted that selecting a whole number of belt teeth per half-turn of the extended belt is a significant factor in determining the appropriate values ​​for these pitches and gear ratios. The drive belt 40B differs from the drive belt of devices 20 and 20A. The drive belt 40B includes a recessed area 152 along the proximal edge section 58B of the belt 40B, which receives an adjacent portion of the distal edge section 56B of the belt 40B when the belt 40B is extended and forms a helix. The recessed portion 152 does not, however, receive the full thickness of the distal edge section 56B, and as a result, a portion of both the distal and proximal edge sections projects radially in opposite directions. A plurality of pegs 154 are located in the recess 152 and engage with a corresponding plurality of holes 156. In the polished version, the pegs 154 are located in the proximal edge section 58B with the holes 156 located in the distal edge section 56B. These positions, however, could be reversed. As the drive belt 40B extends and forms a helix, the engagement of the proximal edge section 58B with an adjacent portion of the distal edge section 56B includes the engagement of pegs 154 with holes 156. In the polished version, the pegs 154 have a chamfered surface 155, which facilitates the insertion and removal of the pegs 154 from the holes 156. The coupling of pins 154 with holes 156 secures adjacent portions of the 40B drive belt to remain axially aligned. This coupling also provides torque transfer between adjacent portions of the extended belt and maintains the stability of the column formed by the extended belt. In the illustrated embodiment, the drive belt 40B has a first main surface 158 and a second main surface 160 on the opposite side of the drive belt 40B. A plurality of gear teeth 78B is formed on the first main surface 158. The gear teeth 78B are engaged by gear members 122B so that the drive assembly 32B can rotate the drive belt 40B and thereby transmit a rotational force to drive the belt 40B. The configuration of the drive belt 40B can take a variety of different forms. In the illustrated embodiment, the plurality of pins 154, recess 152, plurality of holes 156, and gear teeth 78B are all expressed on the first main surface 158. In this respect, it is noted that the opening of the holes 156 in the second main surface 160 is the one that receives the pins 154. Although it is not necessary for the proper functioning of the holes 156 that the holes 156 extend completely to the first main surface 158, extending the holes 156 to the first main surface facilitates the manufacture of the belt 40B.More specifically, it allows the manufacture of a flat strip having two flat surfaces and a subsequent machining or milling operation forming the plurality of pins 154, rebate 152, plurality of holes 156, and gear teeth 78B to be performed from the side of the first main surface 158, without requiring any such operation on the second main surface 160 that forms the opposite side of the strip 40B. This reduces handling of the strip 40B during manufacture, thereby improving efficiency and reducing costs. The strip 40B can be formed from ABS (acrylonitrile butadiene styrene) or another suitable material. For example, although ABS is a relatively flexible material, another relatively flexible material can be used. QC / ynn / eznz / B / Yi more rigid materials such as polycarbonate and metal tapes. When a relatively rigid material is used, it may be advantageous to use a plurality of perforations along the length of the tape to improve the tape's flexibility. Before machining these features on belt 40B, it is a flat belt with two parallel flat surfaces and no features formed on the flat surface. As a result, after forming the pins 154, recess 152, holes 156, and gear tooth grooves 78B, the outermost portions of the first and second main surfaces 158 and 160 define planes 159 and 161, which are parallel to each other, and the distance 162 between these two planes 159 and 161, defined by the first and second main surfaces, defines the greater thickness of the drive belt 40B. As mentioned above, the proximal edge section 58B of the drive belt 40B includes a recess 152 extending along all or substantially all of the length of the drive belt 40B and a plurality of pins 154 located within the recess 152. The proximal edge section 58B defines a proximal edge surface 164 having a first axially oriented longitudinal portion 166 and a second axially oriented longitudinal portion 168. The distal edge section 56B includes a plurality of holes 156 and defines a distal edge surface 170 having a third axially oriented longitudinal portion 172 and a fourth axially oriented longitudinal portion 174. The first and second axially oriented surface portions 166 and 168 are oriented in an axial direction opposite to the axial direction oriented by the third and fourth axially oriented surface portions 172 and 174. Figure 24 shows tape 40B in an unwound condition, and detail D25 is shown in Figure 25. Another view of tape 40B is shown in Figure 25A. As can be understood with reference to Figures 24, 25, and 25A, the proximal edge surface 164 and the distal edge surface 170 extend between the first and second principal surfaces 158 and 160 and, when tape 40B forms a helix, are axially oriented in opposite directions. The first surface portion 166 extends longitudinally with respect to tape 40B and is close to the second principal surface 160, while the second surface portion 168 extends longitudinally with respect to tape 40B and is close to the first principal surface 158. In the illustrated form, the first portion 166 and the second portion 168 are axially separated by a recess 152. The third surface portion 172 extends longitudinally with respect to the strip 40B and is close to the second principal surface 160, while the fourth surface portion 174 extends longitudinally with respect to the strip 40B and is close to the first principal surface 158. In the illustrated form, the third and fourth surface portions 172 and 174 are coplanar. It is further observed that in the illustrated tape 40B, both the first and second principal surfaces 158 and 160 are parallel to the plane defined by the drive tape 40B and the axially oriented portions 166 and 168, 172 and 174 of the proximal and distal edge surfaces 164 and 170 are oriented perpendicularly to the first and second principal surfaces 172 and 174. As is best understood with reference to Figures 26 and 27, in the extended portion of the tape QC / ynn / eznz / B / Yi drive 40B forming a helix, the proximal edge section 58B engages with an adjacent portion of the distal edge section 56B with the second axially oriented longitudinal portion 168 of the proximal edge surface 164 engaged with the third axially oriented longitudinal portion 172 of the distal edge surface 170. The first axially oriented longitudinal portion 166 of the proximal edge surface 164 and the fourth axially oriented longitudinal portion 174 of the distal edge surface 170 extend radially outward in opposite directions. In the illustrated configuration, the first axially oriented longitudinal portion 166 extends radially inward, while the fourth axially oriented longitudinal portion 174 projects radially outward. The drive member 88B includes a helical thread 176 that engages with the first axially oriented longitudinal portion 166 of the proximal edge surface 164. The helical thread 176 can engage with the surface 166 of the drive belt 40B at the transition portion of the drive belt 40B located between the retracted portion 54B, which defines a spiral, and the extended portion 52B, which defines a helix of the drive belt 40B. Because the surface 166 projects radially and is still exposed at the extended portion 52B of the drive belt 40B, the helical thread 176 can also engage with the surface 166 at the extended helical portion 52B of the drive belt 40B. Furthermore, this arrangement also allows the helical thread 176 to engage with the surface 166 for more than 360 degrees around the drive axis 50B.In the illustrated configuration, the helical thread 176 extends for more than 360 degrees around the 50B axis. The ability of the helical thread 176 to engage with the surface 166 after the engagement of the proximal edge section 58B with the distal edge section 56B enables the thread 176 to support axial loads on the extended helical portion of the drive belt and thus allow the pins 154 to engage with the holes 156 in a location where the drive belt 40B does not carry axial load. A belt support member 100B circumscribes the drive belt and defines a second helical thread 178 that engages with the fourth longitudinal portion 174 of the distal edge surface 170. The thread 178 can be applied to the surface portion 174 on the transition portion of the drive belt 40B. However, because the surface 174 projects radially and is still exposed on the extended portion 52B of the drive belt 40B, the helical thread 178 can also be applied to the surface 174 on the extended helical portion 52B of the drive belt 40B. This arrangement also allows the helical thread 178 to engage with the surface 174 for more than 360 degrees around the drive axis 50B. In the polished version, the helical thread 178 extends for more than 360 degrees around the drive shaft 50B and circumscribes the drive belt 40B to the nearest drive member 88B.The 100B belt support member also supports the 118B gear members and can be machined from polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, and sold under various trade names such as Delrin, or formed using other suitable materials and methods. By positioning the helical threads 176 and 178 that extend more than 360 degrees around the QC / ynn / eznz / B / Yi drive shaft 50B and position them close to each other, a short section of the drive belt 40B is simultaneously restrained by both threads 176 and 178, firmly controlling the axial position of the drive belt to facilitate coupling of the drive belt 40B to itself. The use of a helical thread 176 on the drive member 88B that extends for more than 360 degrees around the drive shaft 50B also increases the surface area over which axial compressive forces can be transferred between the drive belt 40B and the drive member 88B. Both the drive member 88B and the belt support member 100B remain stationary relative to each other and the support structure 30B, while the drive belt 40B rotates about the drive axis 50B with respect to these parts when the drive belt 40B extends and retracts. The helical thread 176 in the drive member 88B bears against the belt 40B to withstand axial compressive support forces acting on the extended portion of the drive belt 40B, such as those generated when the drive belt 40B axially pushes a piston 26 in a container 22. The helical thread 178 can engage with portion 174 of the distal edge surface 170 and thus resists tensile forces acting on the drive belt 40B that would act to axially pull the drive belt 40B from the drive member 88B.Helical threads 176 and 178 also axially align the drive belt with itself when the proximal rim section engages with an adjacent portion of the distal rim section as the 40B drive belt extends. With respect to axial compression forces, it is noted that the illustrated drive belt 40B is a one-piece unit belt, and all axial forces transferred between the support member 80B and the drive member 88B when the drive belt is at least partially extended are transferred by the one-piece unit drive belt 40B. The support member 80B includes two fixing pins 180 that are arranged in openings 182 in the belt 40B. A transfer member 84B is rotatably mounted on the support member 80B and engages with the piston 26 when the device 20B is used. The support member 80B transfers axial forces to drive the belt 40B through the engagement of the pins 180 with the openings 182 and through an overlapping flange that is applied to the distal end surface 171 of the distal end of the drive belt 40B. The engagement of the pins 180 with the openings 182 prevents the support member 80B from rotating relative to the drive belt 40B. As the drive belt 40B extends, the support member 80B will exert an axial force on the piston 26 to cause the discharge of medication from the container 22. In this regard, it is noted that the support member 80B exerts this axial force on the piston 26 through the transfer member 84B, which is able to rotate relative to the support member 80B.Thus, during the unloading of a drug, the transfer member 84B will rest on the piston 26 and will not rotate relative to the piston 26 but will rotate relative to the support member 80B. Axial compressive forces are transferred through the tape 40B from the support member 80B to the driving member 88B by the coupling of the second longitudinal portion of the proximal edge surface 168 with the third longitudinal portion of the distal edge surface 172. Although the coupling of pins 154 with holes 156 does not transfer compressive forces in the illustrated configuration, alternative configurations could utilize pins and holes for this purpose. However, the coupling of pins 154 with holes 156 in the illustrated configuration resists axially directed tensile forces acting on the tape 40B and thus resists separation of the extended tape. A reel 104B is rotatable with respect to the drive member 88B, and the retracted portion 54B of the drive belt 40B is stored on reel 40B. Reel 40B rotates along with the drive belt 40B due to the friction coupling of the drive belt 40B with reel 104B. In the illustrated embodiment, the belt 40B is not attached to reel 104B. By not attaching the belt 40B to reel 104B, the short length of belt that would be required to extend and secure to the reel when the drive belt is fully extended can be omitted. Various methods can be used to prevent the unprotected end of the drive belt 40B from extending too far and from escaping the drive mechanism. For example, the gear slots 78B can be terminated in the drive belt 40B at a location that will limit the extension of the belt 40B.A stop in the form of a hook or other gripping member could alternatively or additionally be secured to the end of the drive belt to prevent it from moving through the space between the drive member 88B and the belt support member 100B. Alternatively, a controller can be employed that governs the operation of the motor in a manner that limits the extension of the drive belt 40B and prevents belt escape. The use of a 104B rotating reel helps prevent frictional locking of the retracted portion of the drive belt during extension and retraction. Alternative methods can be used to prevent such frictional locking, such as using a lubricating material to form the drive belt and omitting the rotating reel. In the illustrated version of the 40B drive belt, a portion of the proximal edge surface projects radially inward, while a portion of the distal edge surface projects radially outward. Note that other arrangements are also possible. For example, a portion of the proximal edge surface could project radially outward, and a portion of the distal edge surface could project radially inward. In this alternative embodiment, the helical thread that engages the proximal edge surface and supports axial compressive forces would be positioned radially outward from the drive belt, and the threaded member that engages a portion of the distal edge surface and is positioned to resist axial tensile forces would be positioned radially inward from the drive belt. The offset arrangement of the edge surfaces results in one edge surface having a longer length per unit length of drive tape. In the illustrated modality, the distal edge is the one with the relatively longer length. When drive tape 40B is unwound and laid flat as shown in Figure 24, drive tape 40B defines an arc with the proximal edge section 58B positioned radially inward of the distal edge section 56B. In modalities where the proximal edge protrudes radially outward, the proximal edge section will be positioned radially outward from the distal edge section when the tape is laid flat to define an arc. Another embodiment 20C, similar to device 20B but with a slightly thinner profile, is shown in Figures 30-33. Device 20C differs from device 20B in that it employs several sheet metal parts that allow for a reduction in the size of the housing support structure. More specifically, a metal base plate 184, a metal skirt 186, and a metal support bracket 188 are used in device 20C. As most readily apparent in Figure 33, the motor, gear, drive belt, and reel are the same as those used in device 20B. The belt support member 100C has a slightly different shape but functions in the same manner as the belt support member 100B. As can be seen in Figure 33, the belt support member 100C includes threads 190 for mating threads 148 of the cartridge sleeve 140. Although not shown in the figures for the sake of clarity, the belt support member 100B includes similar threads for mating to the cartridge sleeve 140. The drive member 88C includes a post 192. A key 194 on the post 192 engages with a groove 196 in the base plate 184 and prevents relative rotation of the post 192 and the support structure of which the base plate 184 is a part.The coil 104C is positioned to rotate on post 192 and a washer 198 surrounding post 192 is positioned between base plate 184 and coil 104C to separate coil 104C from base plate 184. Devices 20 and 20A-20C may be provided with or without what is generally referred to as force feedback. Force feedback determines the force acting on piston 26 and thereby allows the device to know the state of container 22 and / or the position of piston 26. If the user is relied upon to prime and confirm the device status, forced feedback is not required. In a device without force feedback, the motor speed and current can be controlled to determine the system status and prevent applying excessive torque to the belt 40 and, consequently, excessive force to the piston 26. The signal-to-noise ratio of the current sensing may be sufficient to detect contact between the distal end of the drive belt and the piston 26. Generally, the system will initiate and complete each dose with the system open to atmospheric pressure through outlet 28. In such a system, the force on the piston 26 is detected; therefore, force feedback is not required for dosing accuracy. If a force feedback system is used, the device will know when the distal end of the transfer member 84 is in contact with the piston 26. This will allow some user steps, such as priming, to be fully or partially automated. A simple force feedback system could employ a contact switch that is triggered by a low force. This switch could be located at the distal end 81 of the drive belt and coupled with the support member 80 or the rotation support 82. Electrical conductors could be arranged in the drive belt to provide electrical communication between the contact switch and a processor inside the housing. Proportional force sensing is also possible if a force-sensing component such as a force-sensitive resistor is used instead of a contact switch.The conductors arranged on the drive tape may terminate within or on the storage reel. If a rotating reel is used, a continuous connection to the device frame may be provided by slip rings or other suitable contacts. The illustrated modalities are electromechanical and controlled by a processor, microcontroller, or microcomputer. The use of a processor allows for the incorporation of numerous interaction points and additional functions into the device. For example, the user can interact with the device using a touchscreen, a multi-button interface, or specific touch points (such as a dose adjustment wheel). If desired, these controls could mimic the interaction behaviors of conventional injection devices. The device could also display a variety of different information, such as the current dose setting, the last dose, reminders and usage keys, or any other useful information. The displays can take the form of a liquid crystal display (LCD), an organic light-emitting diode (OLED), an electronic paper display (EPD), or another suitable display. The device may also be equipped with connectivity that allows it to connect and interact with other devices (e.g., smartphones) using wired or wireless communication techniques. These interactions can be used to exchange information in either direction, allowing (for example) a healthcare professional to change the device settings or download dosage history. Although this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this description. Therefore, this application is intended to cover any variation, use, or adaptation of the invention using its general principles.

Claims

1. A belt used within a container to advance a piston along a drive shaft within the container, the belt comprising: a body having a proximal edge and a distal edge, the body capable of assuming a coiled shape around the drive shaft, and having an inner surface facing the drive shaft and an outer surface facing away from the drive shaft, one of the proximal edge and the distal edge having a plurality of first coupling features, and the other of the proximal edge and the distal edge having a plurality of second coupling features, wherein, in response to a section of the body in the coiled shape forming an interlocking configuration, a portion of the proximal edge of said section couples with an adjacent portion of the distal edge of said section,and each of the plurality of first attachable features is configured to attach to a corresponding one of the plurality of second attachable features along said section.

2. The tape according to claim 1, wherein the body in the coiled form defines a distal end, the tape further comprises a support member supported by the distal end.

3. The belt according to claim 2, further comprising a transfer member rotatably mounted on the support member.

4. The belt according to claim 1, wherein a plurality of teeth is formed along the inner surface, the plurality of teeth configured to engage a mechanical drive to transmit a rotational force through the plurality of teeth to the body.

5. The belt according to claim 1, wherein a plurality of teeth is formed along the outer surface, the plurality of teeth configured to engage a mechanical drive to transmit a rotational force through the plurality of teeth to the body.

6. The tape according to claim 1, wherein the plurality of first attachable features comprises recesses, and the plurality of second attachable features comprises projections, the proximal edge having the plurality of recesses, and the distal edge having the plurality of projections.

7. The tape according to claim 1, wherein the plurality of first attachable features comprises projections, and the plurality of second attachable features comprises recesses, the distal edge having the plurality of recesses, and the proximal edge having the plurality of projections.

8. The tape according to claim 1, wherein one of the proximal edge and the distal edge defines a flange that extends radially.

9. The tape according to claim 1, wherein one of the proximal edge and the distal edge defines an inwardly extending radial tab, and the other of the proximal edge and the distal edge defines an outwardly extending radial tab that is coupled with the inwardly extending radial tab when said body section forms the interlocking configuration.

10. The tape according to claim 1, wherein one of the plurality of first attachable features and the plurality of second attachable features comprises radially extending projections.

11. A drive assembly for a drug delivery device, comprising: a belt comprising a body having a proximal edge and a distal edge, the body being capable of assuming a coiled shape around the drive axis, and having an inner surface facing the drive axis and an outer surface facing away from the drive axis, one of the proximal edge and the distal edge having a plurality of first coupling features, and the other of the proximal edge and the distal edge having a plurality of second coupling features, wherein, in response to a section of the body in the coiled shape forming an interlocking configuration, a portion of the proximal edge of said section engages with an adjacent portion of the distal edge of said section,and each of the plurality of first attachable features is configured to engage with a corresponding one of the plurality of second attachable features along said section; and a mechanical drive having a gear arrangement engaged with a plurality of teeth of the drive belt, and an operating motor for rotating the mechanical drive, wherein, in response to the rotation of the mechanical drive, the section of the belt in the interlocking configuration extends further to advance the piston within the container.

12. The drive assembly according to claim 11, wherein the belt comprises a plurality of teeth formed along the inner surface, and a drive gear of the internal gear arrangement to the belt body in the wound form and configured to engage the plurality of teeth and transmit a rotational force to the body.

13. The drive assembly according to claim 11, wherein one of the plurality of first and second attachable features comprises recesses, and the other of the plurality of first and second attachable features comprises projections.

14. The drive assembly according to claim 11, wherein the belt comprises a plurality of teeth formed along the outer surface, and a drive gear of the gear arrangement is external to the belt body in the wound form and configured to engage the plurality of teeth and transmit a rotational force to the body.

15. A drug delivery device, comprising: a container for holding a drug and defining an outlet, the container further including a piston placed inside the container;a belt comprising a body having a proximal edge and a distal edge, the body being capable of assuming a coiled shape around the drive axis, and having an inner surface facing the drive axis and an outer surface facing away from the drive axis, one of the proximal edge and the distal edge having a plurality of first attachable features, and the other of the proximal edge and the distal edge having a plurality of second attachable features, wherein, in response to a section of the body in the coiled shape forming an interlocking configuration, a portion of the proximal edge of said section engages with an adjacent portion of the distal edge of said section, and each of the plurality of first attachable features is configured to engage with a corresponding one of the plurality of second attachable features along said section;and a mechanical drive having a gear arrangement coupled with a plurality of teeth of the drive belt, and an operating motor for rotating the mechanical drive, wherein, in response to the rotation of the mechanical drive, the belt section in the interlocking configuration extends further to advance the piston within the container to expel medication through the outlet.

16. The device according to claim 15, wherein the mechanical drive includes a worm gear.

17. The device according to claim 15, wherein the mechanical drive includes a gear member.

18. The device according to claim 15, wherein the gear member is placed internally to the body in the coiled form.

19. The device according to claim 15, wherein the belt comprises a plurality of teeth, and a gear of the gear arrangement is configured to engage with the plurality of teeth and transmit a rotational force to the body.

20. The device according to claim 15, wherein the container holds the drug. ABSTRACT A medical delivery device for advancing a piston in a drug container to expel a drug. A support structure supports the container and a drive assembly that advances the piston. The drive assembly includes a retractable and extendable drive belt. The retracted belt defines a spiral, and the extended belt defines a helix. The drive belt can be incrementally moved between the retracted spiral configuration and the extended helical configuration. A mechanical mechanism rotates the drive belt to selectively extend and retract it. A drive member having a helical ramp is applied to a proximal edge of the drive belt where it transitions between a spiral and a helix.A support member at the distal end of the drive belt exerts an axial force on the piston when the belt is extended. Figure 3D is a side view of the second mode with the cover removed and a needle assembly attached. Figure 3E is an end view of the mode in Figure 3D. Figure 3F is a perspective view of the second mode. Figure 4 is a partial schematic perspective view of the drive assembly. Figure 5 is a partial perspective view of the drive belt. Figure 6 is another perspective view of the drive belt. Figure 7 is another partial perspective view of the drive belt. Figure 8 is a detailed partial perspective view of the drive belt. Figure 9 is another detailed partial perspective view of the drive belt. Figure 10 is another detailed partial perspective view of the drive belt.Figure 11 is a schematic perspective view showing an extended portion of the drive belt. Figure 12 is a perspective view of a belt drive member. Figure 13 is a schematic perspective view showing a belt support assembly around a drive belt. Figure 14 is a schematic perspective view showing a mechanical drive assembly for coupling the drive belt. Figure 15 is a schematic perspective view of an alternative mechanical drive assembly. Figure 16 is a schematic perspective view of a drive belt and a storage reel. Figure 17 is a schematic view of the first modality. Figure 18 is a partial perspective view showing the drive assembly and a medication container. Figure 19 is another partial perspective view showing the drive assembly and a medication container.Figure 20 is a partial perspective view of the drive assembly. Figure 21 is a side view of another embodiment. Figure 22 is a partial exploded view of the embodiment in Figure 21. Figure 23 is a cross-sectional view taken along line 23-23 of Figure 26. Figure 24 is a top view of the drive belt of the embodiment in Figure 21. Figure 25 is a view of detail D25 in Figure 24. Figure 25A is an end view of the drive belt of Figure 24. Figure 26 is a side view of a portion of the embodiment in Figure 21 with the housing removed.

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