Patent Publication Number: US-2020289756-A1

Title: Auto injector device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/817,576, entitled “eSecure” and filed on Mar. 13, 2019, which is expressly incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Field 
     The disclosure is generally related to injection devices and more particularly to an auto injector device. 
     Introduction 
     Millions of people suffer from allergies every year, and hundreds of thousands of people may experience severe allergic reactions to certain food types. Many people may also suffer from anaphylaxis, a potentially life-threatening condition requiring emergency medical care for treatment. Epinephrine is a medication that is commonly used to alleviate these allergic reactions and is typically administered using an auto injector. Individuals prone to allergies may carry an auto injector with them at all times for emergencies, and pharmacies and hospitals may store numerous auto injectors for ready use. 
     However, epinephrine auto injectors are generally single-use only, have a short shelf life (e.g. eighteen months or less), and are commonly expensive. Therefore, these auto injectors must be frequently replaced, tend to expire before they are used, and are difficult for many individuals to afford. Epinephrine auto injectors are also generally bulky and inconvenient to carry around, and individuals may forget to carry the auto injectors with them at various times. Epinephrine must also be maintained in a narrow temperature range (e.g. optimally 15-30° C., but preferably 20-25° C.) to avoid degradation and reduced effectiveness, which may be difficult to manage for people in hotter and colder climates and seasons. Additionally, individuals who misuse epinephrine auto injectors may suffer from severe side effects, and it is possible for some individuals who inject the medication correctly to still require medical treatment. 
     SUMMARY 
     Several aspects will be described more fully hereinafter with reference to various illustrative aspects of the present disclosure. 
     One aspect of an auto injector device is disclosed herein. The auto injector device includes a cartridge and an outer casing attached to the cartridge and including a piston. The cartridge is configured to contain a fluid and includes a needle. The piston is configured to pump the fluid in the cartridge through the needle in response to application of a force during injection of the auto injector device. The cartridge is detachable from the outer casing. 
     Another aspect of an auto injector device is disclosed herein. The auto injector device is encapsulated in a case for a mobile communications device and includes a cartridge, and an outer casing fixed to the case and attached to the cartridge and including a piston. The cartridge is configured to contain a fluid and includes a needle. The piston is configured to pump the fluid in the cartridge through the needle in response to application of a force during injection of the auto injector device. The cartridge is detachable from the outer casing. 
     A further aspect of an auto injector device is disclosed herein. The auto injector device is encapsulated in a case for a mobile communications device and includes a cartridge, an outer casing fixed to the case and attached to the cartridge and including a piston, and a sensor attached to the case. The cartridge is configured to contain a fluid and includes a needle. The piston is configured to pump the fluid in the cartridge through the needle in response to application of a force during injection of the auto injector device. The cartridge is detachable from the outer casing. The sensor is in wireless communication with an emergency alert system, and the sensor is configured to sense movement of the needle and to communicate with the emergency alert system in response to application of the force during the injection. 
     It is understood that other aspects of the auto injector device will become readily apparent to those skilled in the art from the following detailed description, wherein various aspects of apparatuses and methods are shown and described by way of illustration. As will be realized, these aspects may be implemented in other and different forms and its several details are capable of modification in various other respects. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of the present invention will now be presented in the detailed description by way of example, and not by way of limitation, with reference to the accompanying drawings, wherein: 
         FIG. 1  is a conceptual diagram of an auto injector device including a case for a mobile communications device, a piston, spring, safety chamber, safety hook, and sensor fixed to the case, and a removable cartridge attached to the piston. 
         FIG. 2  is a conceptual diagram illustrating the piston of the auto injector device of  FIG. 1 . 
         FIGS. 3A-3B  are conceptual diagrams respectively illustrating the spring of the auto injector device of  FIG. 1  in a compressed and expanded state. 
         FIGS. 4A-4D  are conceptual diagrams illustrating an outer casing for enclosing the piston, spring, safety chamber, and safety hook, a removable cartridge of the auto injector device of  FIG. 1 , and a quarter locking mechanism for attaching the cartridge to the outer casing. 
         FIG. 5  is a conceptual diagram illustrating an example spring compression tool for compressing the spring of the auto injector device of  FIG. 1 . 
         FIG. 6  is a conceptual diagram illustrating an example ratio of material used between an inner surface and outer surface of the case of the auto injector device of  FIG. 1 . 
         FIG. 7  is a conceptual diagram illustrating an example emergency alert system in communication with the sensor of the auto injector device of  FIG. 1 . 
         FIGS. 8A-8B  is a flow chart illustrating an example method for operating the auto injector device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of various exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the present invention. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the invention. 
     The words “exemplary” and “example” are used herein to mean serving as an example, instance, or illustration. Any exemplary embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other exemplary embodiments. Likewise, the term “exemplary embodiment” of an apparatus, method or article of manufacture does not require that all exemplary embodiments of the invention include the described components, structure, features, functionality, processes, advantages, benefits, or modes of operation. 
     In the following detailed description, various aspects of an auto injector device will be presented. These aspects are well suited for auto injectors containing epinephrine. However, those skilled in the art will realize that these aspects may be extended to auto injectors containing any type of medication or other fluid. Accordingly, any reference to a specific apparatus or method is intended only to illustrate the various aspects of the present invention, with the understanding that such aspects may have a wide range of applications without departing from the spirit and scope of the present disclosure. 
     Epinephrine auto injectors are used to alleviate severe, life-threatening allergic reactions which users may experience. However, these auto injectors generally have a short shelf life, are typically not reusable, and must be maintained in a narrow temperature range for maximum effectiveness. As a result, epinephrine auto injectors may frequently be discarded (e.g. due to expiration, use, or degradation from higher temperatures), requiring users to restock their supply at least once a year to replace expired, used, or degraded auto injectors. As these auto injectors also tend to be expensive, many consumers may not be able to afford such frequent replacements. Conventional auto injectors are also typically bulky or inconvenient to carry around, resulting in users forgetting to have auto injectors on-hand when needed for emergency use. Additionally, users experiencing anaphylaxis who apply conventional auto injectors may refrain from necessary treatment at a hospital immediately afterwards, increasing the risk of untreated, extreme allergic reactions. 
     To reduce the frequency and cost of restocking auto injectors, the present disclosure provides an auto injector device which includes a replaceable cartridge of epinephrine. The cartridge is attached to an outer casing of the device including a piston, and the piston uses a spring to pump the epinephrine through a needle of the cartridge in response to application of a force during injection of the auto injector device. The force may be applied by the user, e.g. by the user thrusting the cartridge and needle against the user&#39;s thigh or another body part. After the cartridge is emptied, the user may detach the used cartridge from the outer casing and attach a replacement cartridge to the outer casing. The auto injector device may thus be reused numerous times with new cartridges without having to replace the piston, spring, or other reusable components of the device. 
     Moreover, to increase the convenience of carrying auto injectors, the auto injector device is compact and encapsulated in a thermally insulated case. The case may be for a mobile communications device, such as a smartphone. The case may include an inner surface made of fiberglass or other heat-resistant material which insulates the epinephrine and maintains the medication within a preferred temperature range (e.g. 20-25° C.) even in extreme temperature environments (e.g. −29 to 149° C.). The case also includes an outer surface made of polycarbonate or other highly durable material to protect the cartridge and other components of the auto injector device from being damaged from an impact of accidentally dropping the case. 
     The present disclosure also reduces the risk of untreated, extreme allergic reactions by automatically alerting emergency services when the auto injector device is used. A sensor in wireless communication with an emergency alert system is attached to the case for the mobile communications device. The sensor senses movement of the needle in the cartridge when the medication or other fluid is administered. In response to the sensed movement, the sensor communicates with the emergency alert system to sound an alarm and call emergency services. For example, the sensor may trigger the user&#39;s communications device in the case to output an alarm, to communicate with a Public Safety Answering Point (PSAP) (e.g. by calling 9-1-1 or some other number), and to relay the communications device&#39;s location information (e.g. GPS position) and time (e.g. a time stamp corresponding to the time of injection) to the PSAP to be routed to hospitals or other emergency services to dispatch medical personnel to the location. 
     In this way, the present disclosure provides auto injector reusability and saves costs by allowing users to purchase and replace only the cartridge, rather than the entire auto injector device, after the epinephrine is used or discarded. The present disclosure also reduces the frequency of restocking auto injectors and maintains the effectiveness of the epinephrine by thermally insulating the medication within the case for a user&#39;s mobile communications device. The case maintains the temperature of the epinephrine within the preferred temperature range for the medication even in hot or cold environments, thus preventing the shelf life of the auto injector from prematurely degrading. The present disclosure further increases the convenience and portability of auto injectors by fixing the various components of the auto injector device to the case for the mobile communications device, thereby minimizing the likelihood of users forgetting to bring the auto injector device with them when needed. Additionally, the present disclosure reduces the risk of users suffering from untreated, extreme allergic reactions by alerting emergency services in response to application of the auto injector device. 
       FIGS. 1 and 2  illustrate an example auto injector device  100  including a cartridge  102  and a piston  104 . Although not shown in  FIG. 1 , the piston is contained in an outer casing (see outer casing  450  of  FIGS. 4A-4C ) attached to the cartridge. The cartridge  102  may contain a fluid  106 , such as epinephrine or another medication, and the cartridge  102  includes a needle  108  through which the fluid  106  may be dispensed. The piston  104  may be movable within the cartridge  102  to pump the fluid  106  through the needle  108 . For example, the piston  104  may include a flange  110  which presses against the fluid  106  in the cartridge  102  to cause the fluid to move through the needle  108 . The piston may pump the fluid through the needle in response to application of a force during injection of the auto injector device  100  (e.g. in response to forcefully applying the cartridge against a user&#39;s thigh or other injection site), as described for example below with respect to  FIGS. 3A and 3B . Moreover, to provide reusability of the auto injector device  100 , the cartridge  102  is detachable from the outer casing, as described for example below with respect to  FIGS. 4A-4D . 
     The auto injector device  100  includes a safety chamber  112  disposed opposite the cartridge  102 , a spring  118  disposed between the safety chamber  112  and the cartridge  102 , and a safety hook  120  contacting the spring  118 . The safety chamber  112  includes a recess  114  that is sized to receive a portion  105  of the piston  104  (see  FIG. 2 ) between the safety chamber  112  and the cartridge  102 . The portion  105  may include one or more projections  116  that may fit within the recess  114  of the safety chamber  112 . The spring  118  may contact the portion  105  of the piston  104  including the one or more projections  116 . For example, the spring  118  may circumferentially surround the portion  105 , and the one or more projections  116  may extend from the piston  104  to contact and prevent movement of the spring  118 . The safety hook  120  further contacts the spring  118  in addition to the one or more projections  116  to prevent movement of the spring  118 . For example, the safety hook  120  may hook into the spring  118 , as illustrated in  FIG. 1 , or may be otherwise movable between the spring and the piston. 
     Referring to  FIGS. 3A and 3B , the spring  118  may switch between a compressed state  300  (e.g. as shown in  FIGS. 1 and 3A ) and an expanded state  350  (e.g. as shown in  FIG. 3B ). The spring  118  initially is in the compressed state  300 . For example, as illustrated in  FIG. 3A , the piston  104  may include a flange  122  that compresses the spring  118  against the safety chamber  112 . Moreover, the one or more projections  116  as well as the safety hook  120  contacting the spring  118  (see  FIG. 1 ) may initially prevent the spring  118  from expanding away from the safety chamber  112 . In one example, the spring  118  may have a length of 3 cm (or another size) when in the compressed state, and a length of 5 cm (or another size) when in the expanded state. 
     During operation, the user may unhook or move the safety hook  120  away from the spring  118 , and the user may forcefully apply the auto injector device  100  including the cartridge  102  and needle  108  against the user&#39;s thigh or other injection site. Due to spring forces exerted by the spring  118  against the piston  104 , the piston may force the cartridge  102  (e.g. using a flange  123  of the piston as illustrated in  FIG. 1 ) towards the injection site. When the cartridge  102  is forcefully applied in this manner against the injection site, the injection site may apply an equal and opposite force against the cartridge  102  based on Newton&#39;s Third Law of Motion. As a result, the cartridge  102  may similarly apply a force against the piston  104  (e.g. against the flange  123 ), pushing the piston towards the safety chamber  112  and further compressing the spring  118 . 
     At this point, the spring  118  may switch to the expanded state  350 , as illustrated in  FIG. 3B . For example, in response to the force applied by the injection site against the cartridge  102  (and thus the piston  104 ), the portion  105  of the piston  104  including the one or more projections  116  may momentarily enter the recess  114  of the safety chamber  112 , away from contact with the spring  118 . As a result, the spring may become free to release the tension from compression and subsequently expand away from the safety chamber  112  (e.g. against the flange  122  of the piston  104 ) towards the cartridge  102 . In response to the expansion of the spring  118 , the piston  104  may force the cartridge  102  (e.g. using flange  123 ) toward the injection site and pump the fluid  106  within the cartridge (e.g. via the flange  110  shown in  FIG. 1 ) through the needle  108  into the injection site. For example, the spring  118  may be configured to have a sufficiently large wire diameter (e.g. 1.485 mm), outer diameter (e.g. 14.5 mm), free length (e.g. 50 mm), and number of active coils (e.g.  18 . 2 ) to provide sufficient force (e.g. greater than 71.2 N) to fully administer the injection. After use, the cartridge  102  may be detached from the outer casing including piston  104 , as described below with respect to  FIGS. 4A-4D . 
     Referring to  FIGS. 4A-4D , the auto injector device  400  may include an outer casing  450  which includes various components of the device, including the piston  404 , the safety chamber  412 , the spring  418 , and the safety hook (not shown), but which does not include the cartridge  402  with fluid  406  and needle  408 . In particular,  FIG. 4A  illustrates the various components of the auto injector device  400  removed from the outer casing  450 ,  FIG. 4B  illustrates a partial view of the components of the auto injector device  400  within the outer casing  450  and attached to the cartridge  402 , FIG.  4 C illustrates an enlarged view of a locking mechanism for attaching the outer casing  450  to the cartridge  402 , and  FIG. 4D  illustrates an example configuration of the locking mechanism. The auto injector device  400  may correspond to the auto injector device  100  of  FIG. 1 . Similarly, the cartridge  402 , piston  404 , fluid  406 , needle  408 , safety chamber  412 , spring  418 , and safety hook may correspond to the cartridge  102 , piston  104  (including first flange  122 , second flange  123 , and third flange  110 ), fluid  106 , needle  108 , safety chamber  112 , spring  118 , and safety hook  120  respectively shown in  FIGS. 1 and 2 . 
     As illustrated in  FIG. 4B , the outer casing  450  may include the piston  404  (as well as the safety chamber  412 , spring  418 , and safety hook). The cartridge  402  may be detachable from the outer casing  450 . For instance, the cartridge  402  and outer casing  450  may together include a quarter locking mechanism  460  (see  FIG. 4C ) in which the cartridge  402  may be rotated clockwise (or counterclockwise) 90 degrees with respect to outer casing  450  into locking engagement with the outer casing  450  (e.g. via threads  462 , grooves  464 , etc.). In this way, the cartridge  402  may be detached from the outer casing  450  after use (e.g. dispensation of the fluid as described above) or expiration, and a replacement cartridge may be similarly attached to the outer casing  450 , thereby providing reusability of the auto injector device without having to discard or replace the piston, safety chamber, spring, safety hook, or other components of the outer casing after use. 
     As illustrated in  FIG. 4A , the cartridge  402  may also include a cap  452  which covers the needle  408 . The cap  452  may be sized relative to the needle  408  to facilitate use of the quarter locking mechanism. For example, the cap may be longer than the needle, as shown in  FIG. 4A , such that it snugly contacts the cartridge  402 . In this way, when a replacement cartridge is being attached to the outer casing  450  using quarter locking mechanism  460 , the cartridge  402  may be rotated using the cap  452  into locking engagement with the outer casing  450 . The cap may be subsequently removed to enable use of the needle  408 . The cap  452  thus allows the cartridge  402  to be easily and safely attached to the outer casing when the auto injector device  400  is carried in an enclosure such as the case  124  described below. 
     Referring back to  FIG. 1 , the auto injector device  100  may further be encapsulated in a case  124  to which the piston  104 , the spring  118 , the safety chamber  112 , and the safety hook  120  are fixed. The case  124  may include a first opening  126  configured to hold a mobile communications device (not shown), such as a smartphone, tablet, or the like, in addition to the other components of the auto injector device. For example, the case  124  may include a cavity  127  inside the first opening  126  in which the outer casing  450  may be attached, and the mobile communications device may be placed through the first opening  126  on top of the cavity  127  above the outer casing  450 . 
     The case  124  may further include a second opening  128  (e.g. at the bottom of the case  124  or some other location) separate from the first opening  126 . The cartridge  102  may be detached from the outer casing  450  fixed to the case through the second opening  128  without removing the mobile communications device. For example, the cartridge  102  may be detached through the second opening  128  from the outer casing  450  fixed to the case using the quarter locking mechanism  460  described above with respect to  FIGS. 4A-4C . A replacement cartridge may similarly be attached to the outer casing through the second opening  128  using cap  452 , and the cap  452  may be removed after replacing the cartridge. Thus, the case  124  may provide portability and convenience by allowing users to carry and use the auto injector device  100  along with their cellular phone or other communications device. Moreover, the case  124  facilitates reusability of the auto injector device by enabling users to safely remove and replace used cartridges (e.g. using the cap  452 ) without having to remove the mobile communications device or otherwise reach into the case  124  (e.g. through either opening  126  or  128 ). 
     Referring now to  FIG. 5 , when the spring  118  expands as shown in  FIG. 3B  to dispense the fluid  106  in the cartridge  102 , the cartridge  102  may be detached from the outer casing  450  through the opening  128  of the case  124 . Before a replacement cartridge  102  is attached to the outer casing  450 , the spring  118  must be reset into the compressed state shown in  FIG. 1 or 3A .  FIG. 5  illustrates a spring compression tool  500  that may be used to facilitate the re-compression of the spring  118  after detachment of a used cartridge. The spring compression tool  500  includes a head  502  supported by a body  504 . The head  502  and body  504  may be sized to exert a force against the spring  118  through the opening  128  inside the case  124  to place the spring back into the compressed state. For example, the head  502  may have a width sufficient to clear the opening  128  of the case  124 , and the body  504  may have a length spanning a majority of the length of the case  124 . Moreover, if the outer casing  450  containing the piston  404  illustrated in  FIG. 4B  is elliptical in shape, the head  502  may also be elliptical in shape to fit within the outer casing and contact the piston. 
     When the spring compression tool  500  is inserted through the opening  128  such that the head  502  contacts the piston  104  (e.g. the flange  110 ), a force may be applied by the spring compression tool  500  against the piston  104 , causing the piston to compress the spring  118  (e.g. via the flange  122 ) against the safety chamber  112 . The one or more projections  116  of the piston  104  (see  FIG. 2 ) may subsequently contact and prevent movement of the spring, as illustrated in  FIG. 3A . The safety hook  120  may also be reattached to the spring  118  to further prevent movement of the spring. For example, referring to  FIG. 1 , the safety hook  120  may be movably mounted to a side of the case  124  through an opening  129  or may hook around the side of the case  124  into the cavity  127 , and the safety hook  120  may be pivoted, translated, or otherwise adjusted relative to the side of the case to contact (and release contact of) the spring  118 . Once the spring  118  is compressed, the spring compression tool  500  may be removed from the opening  128 , and a replacement cartridge may subsequently be attached. 
     The spring  118  may be configured such that the spring compression tool  500  may sufficiently compress the spring from the expanded state  350  to the compressed state  300  using manual force. For example, the spring may be sized such that the amount of force needed to compress the spring is less than the maximum force capable of being manually applied by a user&#39;s hand. For instance, in the case where the spring spans 3 cm in the compressed state and 5 cm in the expanded state, a force of only 30.16 N or 3.08 kg may be required to compress the spring by 2 cm, which is less than the maximum force capable of being manually applied by a user&#39;s hand (e.g. 4.6 kg). In this way, a user may easily reset the spring  118  of the auto injector device  100  simply using the spring compression tool  500  when attempting to replace a used cartridge. 
     The case  124  may include a mixture of durable and heat-resistant materials. For instance,  FIG. 6  illustrates an example diagram  600  showing a ratio of materials comprised in the case  124  of  FIG. 1 . For example, an outer portion  602  of the case  124  (e.g. which includes an outer surface  130 ,  603  of the case) may be comprised of polycarbonate or other durable material, while an inner portion  604  of the case  124  (e.g. which includes an inner surface  132 ,  605  of the case) may be comprised of fiberglass or other heat-resistant material. To provide thermal insulation, the inner portion  604  may be twice the size of the outer portion  602 . For instance, assuming the case  124  has side width of 0.3 cm, 0.2 cm comprising the inner portion  604  may be comprised of fiberglass material while 0.1 cm comprising the outer portion  602  may be comprised of polycarbonate material. Alternatively, other ratios of heat-resistant to durable material besides 2:1 may be used. In this way, the case  124  may thermally insulate the fluid  106  in the cartridge  102  to a preferred temperature range (e.g. 20-25° C.) even in hot and cold environments, as well as protect the components of the auto injector device  100  (in addition to the mobile communications device) from drops or other impacts. Additionally, the components of the auto injector device  100  (e.g. the piston  104 , safety chamber  112 , and safety hook  120 , etc.) may be comprised of heat-tolerant and fatigue-resistant material, such as polypropylene plastic, for added thermal insulation and protection of the auto injector device. 
     When a user injects the epinephrine, medication, or other fluid  106  in the cartridge  102  as described above, the user may still require treatment or hospitalization. For example, the user may still experience a severe allergic reaction or one or more side effects such as nausea, etc. Moreover, the user may also fall unconscious, or may be otherwise unable to immediately seek medical attention. Accordingly, the auto injector device  100  may include a sensor  134  attached to the case  124  which is in wireless communication with an emergency alert system. 
       FIG. 7  illustrates an example diagram  700  of a sensor  702  in wireless communication with an emergency alert system  704 . The sensor  134 ,  702  may be positioned in the case  124  to sense movement of the needle  108  during administration of the fluid  106  in the cartridge  102 . In response to movement of the needle  108  (e.g., as described above with respect to  FIG. 3A ), the sensor  134 ,  702  may communicate with the emergency alert system  704 , e.g. via the mobile communications device  706 , to alert hospitals or other emergency services of the location of the mobile communications device and the time of the fluid administration. In one example, the sensor  134 ,  702  may wirelessly communicate with the emergency alert system  704  using Bluetooth or other wireless technology standard. For example, the sensor may communicate via cellular communication (e.g. 5G NR, 4G LTE, 3G, 2G, GSM/UMTS, CDMA One/CDMA2000, etc.), wireless distribution methods through access points (e.g. IEEE 802.11, WiFi, HiperLAN, etc.), Infra Red (IR), Bluetooth, Zigbee, or other Wireless Wide Area Network (WWAN), Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN) technology, or comparable wide area, local area, and personal area technologies. The sensor  134 ,  702  may be a stand-alone sensor, or may be an on-board component of a system including one or more sensors (e.g. gyroscopes, accelerometers, magnetometers, temperature sensors, photo sensors, etc.) and/or other components (e.g. a processor, a memory, a battery, etc.). 
     Sensor  702  may be configured to communicate sensor information  709  in response to a detection of movement of the needle  108 . For example, sensor  702  may be programmed via an application programming interface (API)  707  to transmit sensor information  709  to an application of the mobile communications device  706  in response to the movement. The application of the mobile communications device may be configured to activate an alert confirmation  708  in response to the sensor information  709 . The sensor may also be configured to sound an alarm  711  (e.g. from the mobile communications device  706  and/or using a separate speaker). 
     The alert confirmation  708  may output an alert requesting a response within a predetermined period of time before emergency services are notified. For instance, the sensor  702  may be programmed using the API  707  to trigger the application of the mobile communications device  706  to display and/or sound an alert that an injection of epinephrine has been detected, and to request a confirmation that the detection is accurate within 5 seconds or some other time interval. The alert confirmation  708  thus may serve to prevent notification of emergency services due to false alarms (e.g. erroneous movement of the needle). If an input is received into the application (e.g. via a microphone or the display of the mobile communications device) within the predetermined period of time confirming that the detection was a false alarm, the alert is dismissed and no further action is taken. 
     Otherwise, if the input confirms the detection is accurate, or if no input is received at all within the predetermined period of time (for instance, the user is unconscious), the application may trigger the mobile communications device  706  to communicate with a PSAP  710  to request emergency services  712 . For example, the application may trigger the mobile communications device  706  to call 9-1-1 and provide a minimum set of data (MSD) for emergency services to the PSAP. The MSD may include location information  714  indicating a location of the mobile communications device  706  or sensor  702  (e.g. Global Positioning Satellite (GPS)), and time information  716  indicating a time when injection was administered (e.g. a time stamp when the call was made to the PSAP  710 ). Based on the MSD, the PSAP operator may be able to dispatch emergency services  712  (e.g. paramedics, medical professionals, etc.) to the location of the user. In this way, the auto injector device  100  may allow a user to readily receive medical treatment in the event the epinephrine or other medication was ineffective or caused unanticipated side effects, thereby reducing the risk of users suffering from untreated, extreme allergic reactions. 
       FIGS. 8A-8B  are a flow diagram illustrating a method  800  of operating an auto injector device as described in the examples of  FIGS. 1-7 . The method may be performed by users of the auto injector device, such as consumers or medical personnel. Optional aspects are illustrated in dashed lines. 
     Referring to  FIG. 8A , as represented by block  802 , the safety hook is initially removed from contact with the spring. For example, referring to  FIGS. 1 and 2 , the safety hook  120  fixed to the case  124  may be pivoted, translated, or otherwise adjusted to release contact of the spring  118 . For instance, the safety hook may be pulled or pivoted away from the spring  118 . 
     As represented by block  804 , a force is applied during injection of the auto injector device to pump fluid within the cartridge. For instance, as represented by block  806 , the spring may compress using the piston towards the safety chamber, and as represented by block  808 , the spring may expand from the safety chamber against the piston towards the cartridge to pump the fluid through the needle. For example, referring to  FIGS. 1, 3A and 3B , after the user unhooks or moves the safety hook  120  away from the compressed spring  118 , the user may forcefully apply the case  124  including the cartridge  102  and needle  108  against the user&#39;s thigh or other injection site. As a result, the injection site may apply an equal and opposite force against the cartridge  102 , pushing the piston towards the safety chamber  112  and further compressing the spring  118 . Subsequently, the portion  105  of the piston  104  including the one or more projections  116  may momentarily enter the recess  114  of the safety chamber  112 , away from contact with the spring  118 . As a result, the spring may become free to release the tension from compression and subsequently expand away from the safety chamber  112  towards the cartridge  102 . In response to the force applied by the spring  118 , the piston  104  may pump the fluid  106  within the cartridge through the needle  108  into the injection site. 
     As represented by block  810 , the movement of the needle is sensed. For example, referring to  FIGS. 1 and 7 , a sensor  134 ,  702  may be positioned in the case  124  to sense movement of the needle  108  during administration of the fluid  106  in the cartridge  102 . As described above with respect to block  804 , when the user forcefully applies the case  124  including the cartridge  102  and needle  108  against the user&#39;s thigh or other injection site, the piston may force the cartridge  102  and needle  108  towards the injection site due to spring forces exerted by the spring  118  against the piston  104 . The sensor  134 ,  702  may detect the movement of the needle, for instance, by optically detecting light no longer blocked by the position of the needle, or in other manners. 
     As represented by block  812 , communication with an emergency alert system may be triggered. For example, as represented by block  814 , an alert confirmation may be triggered, and as represented by block  816 , emergency services may be notified. For instance, referring to  FIGS. 1 and 7  and in response to movement of the needle  108 , the sensor  134 ,  702  may communicate with the emergency alert system  704 , e.g. via the mobile communications device  706 , to alert hospitals or other emergency services of the location of the mobile communications device and the time of the fluid administration. For example, the sensor may be configured or programmed (e.g. using an application programming interface (API)  707 ) to trigger an application of the mobile communications device  706  to activate an alert confirmation  708  in response to sensor information  709  detecting movement of the needle  108 . The alert confirmation  708  may be configured to output an alert from the mobile communications device  706  which requests a response within a predetermined period of time. If a response is received confirming the detection is accurate, or if no response is received at all within the predetermined period of time (for instance, the user is unconscious), the application may be configured to trigger the mobile communications device  706  to communicate with a PSAP  710  to request emergency services  712 . 
     Referring now to  FIG. 8B , after the cartridge is used, as represented by block  818 , the removable cartridge is detached from the outer casing through the case. For instance, referring to  FIGS. 1 and 4A-4D , the cartridge  102  may be detached from the outer casing  450  fixed to the case through the opening  128  without removing the mobile communications device. For example, the cartridge  102  may be detached through the opening  128  from the outer casing  450  fixed to the case using the quarter locking mechanism  460  described above with respect to  FIGS. 4A-4D . 
     As represented by block  820 , the spring is reset to its compressed state using a spring compression tool. For example, referring to  FIG. 5 , a spring compression tool  500  may be used to facilitate the re-compression of the spring  118  after detachment of a used cartridge. The spring compression tool  500  includes a head  502  supported by a body  504  which may be sized to exert a force against the spring  118  through the opening  128  inside the case  124  to place the spring back into the compressed state. 
     As represented by block  822 , the safety hook may be re-attached to the compressed spring. For example, referring to  FIGS. 1 and 5 , after the spring compression tool  500  is inserted through the opening  128  and applies a force causing the piston to compress the spring  118  against the safety chamber  112 , the safety hook  120  may also be reattached to the spring  118  to prevent movement of the spring. For example, referring to  FIG. 1 , the safety hook  120  may be movably mounted to a side of the case  124 , and the safety hook  120  may be pivoted, translated, or otherwise adjusted relative to the side of the case to contact the spring  118 . The one or more projections  116  of the piston  104  may also contact and prevent movement of the spring, as illustrated in  FIG. 3A . 
     Lastly, as represented by block  824 , a replacement cartridge is attached to the outer casing through the case. For example, referring to  FIGS. 1 and 4A-4B , once the spring  118  is compressed as described with respect to block  820  and the spring compression tool  500  is removed from the opening  128 , a replacement cartridge may subsequently be attached to the outer casing  450  through the opening  128  using cap  452 . For example, the cartridge  102  may be attached through the opening  128  to the outer casing  450  fixed to the case using the quarter locking mechanism  460  described above with respect to  FIGS. 4A-4D . The cartridge  102  is placed through the second opening  128  using cap  452  for attachment to the outer casing  450 , and the cap  452  is removed after replacing the cartridge. 
     As a result, the present disclosure provides for reusability, portability and convenience, thermal insulation, and safety in using the auto injector device. By allowing cartridges to be detachable from the outer casing after use or expiration and new cartridges to be attachable to the outer casing for subsequent use, the auto-injector device may be cost-effectively re-used without having to replace the case, piston, spring, safety chamber, and safety hook after each use. Moreover, by fixing the piston, spring, safety chamber, and safety hook to the case, the auto injector device may be portable and convenient to carry with the user&#39;s mobile communications device, minimizing risk of a user forgetting to carry the auto injector device when needed. Furthermore, the heat-resistant material of the inner portion of the case and durable material of the outer portion of the case respectively allow the epinephrine or other medication or fluid in the auto injector device to maintain an optimal temperature notwithstanding hot and cold environments and to protect the components of the auto injector device from drops or other impact, thereby preserving the effectiveness and integrity of the auto injector device. Additionally, by incorporating a sensor fixed to the case that is configured to wirelessly communicate with an emergency alert system in response to movement of the needle, the auto injector device may provide increased safety to users who experience unconsciousness, severe allergic reactions, side effects, or other conditions from using the auto injector device. 
     The various aspects of this disclosure are provided to enable one of ordinary skill in the art to practice the present invention. Various modifications to exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art, and the concepts disclosed herein may be extended to other magnetic storage devices. Thus, the claims are not intended to be limited to the various aspects of this disclosure, but are to be accorded the full scope consistent with the language of the claims. All structural and functional equivalents to the various components of the exemplary embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112(f) in the United States, or an analogous statute or rule of law in another jurisdiction, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”