Patent Publication Number: US-10767944-B2

Title: Auto-releasing method and arrangement of detachable magazine for firearm

Description:
CROSS REFERENCE OF RELATED APPLICATION 
     This application is a Divisional application that claims the benefit of priority under 35 U.S.C. § 120 to a non-provisional application, application Ser. No. 15/900,744, filed Feb. 20, 2018, which is incorporated herewith by references in their entities. 
    
    
     NOTICE OF COPYRIGHT 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE PRESENT INVENTION 
     Field of Invention 
     The present invention relates a firearm, and more particularly, to a firearm magazine comprising an auto-releasing method and arrangement of firearm magazine that enables the magazine of a firearm automatically detaching and removing from the magazine receiving cavity of the firearm when the last cartridge in the magazine is chambered (has been fed to be loaded in the barrel of the firearm), it allows the operator to immediately insert a loaded magazine into the magazine receiving cavity of the firearm while there is still a last round of cartridge reminded loaded in the firearm barrel. 
     Description of Related Arts 
     A firearm, such as a rifle or pistol, inflicts damage on target by launching one or more cartridges or bullets driven by rapidly expanding high-pressure gas produced by exothermic combustion within an ammunition cartridge. Equipped with powerful firearm, anti-terrorism force, police force or military force, for example, can effectively eliminate terrorists, armed criminals or enemies to prevent any potential risks or damages. A gun-battle may occur in an anti-terrorism event or battle, during which the shooting performance of the firearm substantially determines the survival probability for the anti-terrorism force. 
     Most handgun or rifle, the magazine follower engages a slide-stop to hold the slide back and keep the firearm out of battery when the magazine is empty and all rounds fired. Upon inserting a loaded magazine, the operator depresses the slide stop, throwing the slide forward, stripping a round of cartridge from the top of the magazine stack and chambering it. In single-action pistols this action keeps the hammer cocked back as the new round of cartridge is chambered, keeping the handgun ready to begin firing again. 
     In particular, during the gunfight, gun shooters must be highly focused on on-site observation and shooting, such that they generally may not realize a magazine is empty until the last cartridge in the magazine is fired out and the slide-stop held the slide back and kept the firearm out of battery. In order to continue firing, the operator has to manually actuate a magazine release button on a side of the firearm, which is fixed in place in the magazine receiving cavity by a magazine catch body, to release and remove the empty magazine, and then insert a loaded magazine in the magazine receiving cavity. Finally, the operator has to depress the slide stop, throwing the slide forward, stripping a round of cartridge from the top of the magazine stack and chambering it in order to set the firearm in a firing mode. 
     Accordingly, the firearm is empty with cartridge while the procedures of reloading magazine as mentioned above for a certain period of time. It is well known that time is the lifeline for the parts engaging in a gunfight, where the one, who has stronger and continuing firing, has greater chance to survive. In practice, the operator of the firearm is virtually in a weapon-less manner, when the magazine of the firearm is empty with all rounds fired and the reloading operation is not finished yet, that he is vulnerable to being shot. In contrast, the other party in a gunfight can easily suspect and speculate a firing blank and catch this golden opportunity to attach or shot the one who is operating the reloading of the firearm. It is inevitably since such opportunity is given by the natural firing limits of the conventional firearms. 
     Similarly, a conventional firearm, such as CQ-A 5.56 automatic rifle, includes an upper receiver, a barrel mounted on the upper receiver, a firing mechanism removably coupled with the upper receiver, a bolt assembly received within the upper receiver, and a gas piston system, wherein the gas piston system incorporates with the bolt assembly to cycling the firing mechanism of the firearm in an automatic or semi-automatic manner. 
     In particular, during the firing operation, a bolt of the bolt assembly is arranged to be blocked by a bolt catch and a hammer of the firing mechanism is automatically shifted at a stand-by state to physically inform the operator that the last cartridge of the magazine is fired out. In order to continue to fire, the operator must depress a magazine catch to release the magazine and after changing another loaded magazine, the operator has to depress the bolt catch to release the bolt so as to load a new cartridge into the firing chamber to shoot. Accordingly, such firing mechanism causes great troubles in case that the time spent on changing the magazine and operating the bolt assembly could result in death during a gunfight as described above. 
     Consequently, in order to eliminate the firing blank period, some operators choose to replace the magazine before it is empty and all rounds fired out intentionally, such that the operator is remained ready to fire while changing the magazine and able to continue firing at once after the new magazine is loaded. However, as mentioned above, the man, at an exclusively intensive occasion, is unable to pay attention to the state of the magazine consciously. It is absolutely a waste of ammunition when all rounds of the magazine are not completely fired while, generally, there are limited loaded magazines carried by the operator to be reloaded for the firearm during a gunfight. 
     Therefore, it will be greatly appreciated if there is a way to economically and conveniently inform the operator the state of the magazine, especially when there is only one cartridge left in the firing chamber of the firearm, and to allow the operator to change a loaded magazine while the last cartridge is still chambered and ready to fire. 
     SUMMARY OF THE PRESENT INVENTION 
     The invention is advantageous in that it provides a detachable magazine of a firearm with auto-releasing arrangement, wherein the magazine allows an operator at the time that the last round of cartridge in the magazine is chambered in the firearm physically, the magazine automatically releases from the firearm for removal such that the operator is able to reload another loaded magazine while the firearm is still at a firing mode. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a detachable magazine for a firearm, which incorporates with a magazine catch of the firearm to produce a signal to inform the operator physically at the time when the last cartridge of the magazine is loaded in the firearm. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a detachable magazine for a firearm, wherein the auto-releasing arrangement is able to physically remind the operator that it is the right time to replace the magazine and to continue fire without having to performing a series of magazine reloading operations to reset the firearm into the fire mode, wherein the magazine will automatically be released and removed from the magazine receiving cavity of the firearm. In other words, the operator can simply insert another loaded magazine into the magazine receiving cavity while the firearm still has at least one cartridge chambered for firing, so that the time cost on performing such operations can substantially be saved to increase the survival probability during a gunfight or the like. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a magazine for a firearm, which is able to actuate the magazine release button to depress the magazine catch to release the locking state of the magazine in the magazine receiving cavity of the firearm at the time that the last cartridge in the magazine is chambered and loaded automatically, thereby mechanically releasing the empty magazine and inform the operator to change for another loaded magazine. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of magazine for firearm, wherein a snap-out sound is generated when the auto-releasing arrangement of the magazine actuate the magazine catch to release the empty magazine to inform the operator for replacing another loaded magazine acoustically. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a magazine for a firearm, wherein at the time the last round of cartridge in the magazine is chambered and loaded, the magazine will be released and detached by means of the auto-releasing arrangement automatically for removal, wherein the empty magazine may drop off the magazine receiving cavity of the firearm due to gravity and the operator may immediately replace another loaded magazine into the magazine receiving cavity while there is still at least one round of cartridge chambered and ready for firing during the replacement of the magazine. In addition, after the loaded magazine is replaced, for example a ten rounds magazine, the firearm has a total of (10+1) eleven rounds of cartridge loaded for firing. In other words, when the operate fires the last round of cartridge of the last magazine remained in the firing chamber of the barrel of the firearm, the uppermost cartridge of the newly loaded magazine will be chambered automatically for firing that substantially avoids the slide-stop of the firearm holding the slide back and kept the firearm out of battery as in the conventional reloading operation that requires the operator to depress the slide stop, throwing the slide forward, stripping a round of cartridge from the top of the magazine stack and chambering it in order to set the firearm in a firing mode again. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a magazine for a firearm which does not required to have any complicated and expensive components or modifications employed. In one embodiment, the firearm may simply modify the size of the magazine receiving cavity to match the size of the magazine with the auto-releasing arrangement of the present invention without the need to change its structure at all. 
     Another advantage of the invention is to provide an auto-releasing method and arrangement of a magazine which is adapted to be used for a conventional firearm while providing the conventional firearm with the function of auto-releasing the magazine or replacement of another loaded magazine when the last round of cartridge is chambered in the firearm. Additional advantages and features of the invention will become apparent from the description which follows, and may be realized by means of the instrumentalities and combinations particular point out in the appended claims. 
     According to the present invention, the foregoing and other objects and advantages are attained by a detachable magazine adapted for a firearm having a magazine receiving cavity and comprising a magazine catch mechanism for locking the magazine inserted in the magazine receiving cavity in position, wherein the magazine comprises: 
     a magazine casing having a cartridge chamber therein adapted for receiving one or more cartridges and a cartridge opening communicating with the cartridge chamber to allow the cartridges feeding in and out therethrough; 
     a cartridge follower housed in the cartridge chamber; 
     a resilient element housed in the cartridge chamber and extended between a base of the magazine casing and the cartridge follower for providing a resilient force against the cartridge follower towards the cartridge opening, thereby the cartridges fed in the cartridge chamber are guided one after one between the cartridge follower and the cartridge opening that maintains an uppermost cartridge of the cartridges housed in the magazine at a position of the cartridge opening; and 
     an auto-releasing arrangement comprising an actuator mounted in the cartridge chamber of the magazine casing in such a manner that the actuator is driven to move up and down along with a movement of the cartridge follower, wherein when the cartridge follower is moved by the resilient element to an uppermost position and adjacent to the cartridge opening while the last cartridge of the cartridges housed in the cartridge chamber is chambered and loaded in the firearm and leaving the magazine having no cartridge therein, the actuator actuates the magazine catch of the firearm to unlock and release the magazine for removal from the firearm. 
     According to another aspect of present invention, the present invention provides an auto-releasing method of a magazine for a firearm, comprising the steps of: 
     (a) driving an actuator to move along with a movement of a cartridge follower mounted in a cartridge chamber of a magazine casing of the magazine and supported by a resilient element housed in the cartridge chamber and extended between a base of the magazine casing and the cartridge follower; and 
     (b) actuating a magazine catch of the firearm which is configured to lock the magazine inserted in a magazine receiving cavity of the firearm in position to unlock and release the magazine for removal from the magazine receiving cavity while a last cartridge of one or more cartridges housed in the magazine casing is leaving the magazine and chambered and loaded in the firearm for firing, such that an operator of the firearm is able to detach the empty magazine and replace another loaded magazine in the magazine receiving cavity of the firearm while there is still one cartridge being chambered and ready for firing. 
     In one embodiment, after the step (b) of the auto-releasing method of the present invention, the auto-releasing method further comprises a step (c) of generating a snap sound at the time when the last cartridge in the magazine is chambered and the magazine catch is released by the actuator. 
     Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. 
     These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a firearm, which is embodied as a rifle, according to a first preferred embodiment of the present invention. 
         FIG. 2  is a schematic view of the firearm when the magazine is fully detached from the magazine receiving cavity of the firearm according to the above first preferred embodiment of the present invention. 
         FIG. 3  is an exploded view of a magazine of the firearm according to the above first preferred embodiment of the present invention. 
         FIG. 4  is a sectional view of the magazine, illustrating the relationship between the magazine catch and the magazine loaded with cartridges, according to the above first preferred embodiment of the present invention. 
         FIG. 5  is a sectional view of the magazine, illustrating the relationship between the magazine catch and the magazine when only one cartridge remained in the magazine, according to the above first preferred embodiment of the present invention. 
         FIG. 6  is a sectional view of the magazine, illustrating the relationship between the magazine catch and the magazine after the last cartridge of the magazine is chambered and leaving no cartridge in the magazine, according to the above first preferred embodiment of the present invention. 
         FIG. 7  is a schematic view of the firearm when the last cartridge of the magazine is chambered loaded into a firing chamber and the magazine is initially released from the magazine receiving cavity of the firearm according to the above first preferred embodiment of the present invention. 
         FIG. 8  is a schematic view of a firearm, which is embodied as a pistol, according to a second preferred embodiment of the present invention. 
         FIG. 9  is a schematic view of the firearm when the magazine is fully detached from the magazine receiving cavity of the firearm. 
         FIG. 10  is an exploded view of a magazine of the firearm according to the above preferred embodiment of the present invention. 
         FIG. 11  is a sectional view of the magazine, illustrating the relative relationship between the magazine catch and the magazine loaded with cartridges, according to the above second preferred embodiment of the present invention. 
         FIG. 12  is a sectional view of the magazine, illustrating the relative relationship between the magazine catch and the magazine when only one cartridge remained in the magazine, according to the above second preferred embodiment of the present invention. 
         FIG. 13  is a sectional view of the magazine, illustrating the relative relationship between the magazine catch and the magazine after the last cartridge of the magazine is chambered and leaving no cartridge in the magazine, according to the above second preferred embodiment of the present invention. 
         FIG. 14  is a schematic view of the firearm when the last cartridge of the magazine is loaded into a firing chamber and the magazine is initially released from the magazine receiving cavity of the firearm. 
         FIG. 15  is an exploded view of an alternative mode of the detachable magazine of the firearm of the above first preferred embodiment of the present invention. 
         FIG. 16  is a sectional view of the alternative mode of the magazine of the above first preferred embodiment of the present invention, illustrating the relationship between the magazine catch and the magazine loaded with cartridges. 
         FIG. 17  is a sectional view of the alternative mode of the magazine of the above first preferred embodiment of the present invention, illustrating the relationship between the magazine catch and the magazine when only one cartridge remained in the magazine. 
         FIG. 18  is a sectional view of the alternative mode of the magazine of the above first preferred embodiment of the present invention, illustrating the relationship between the magazine catch and the magazine after the last cartridge of the magazine is chambered and leaving no cartridge in the magazine. 
         FIG. 19  is an exploded view of an alternative mode of the detachable magazine of the firearm according to the above preferred embodiment of the present invention. 
         FIG. 20  is a sectional view of the alternative mode of the magazine of the above second preferred embodiment of the present invention, illustrating the relative relationship between the magazine catch and the magazine loaded with cartridges. 
         FIG. 21  is a sectional view of the alternative mode of the magazine of the above second preferred embodiment of the present invention illustrating the relative relationship between the magazine catch and the magazine when only one cartridge remained in the magazine. 
         FIG. 22  is a sectional view of the alternative model of the magazine of the above second preferred embodiment of the present invention, illustrating the relative relationship between the magazine catch and the magazine after the last cartridge of the magazine is chambered and leaving no cartridge in the magazine. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention. 
     Referring to  FIGS. 1 to 8  of the drawings, a detachable magazine  20 ,  20 ′ with auto-releasing arrangement for a firearm  10 , which is embodied as a rifle according to a first preferred embodiment of the present invention is illustrated. Referring to  FIGS. 8 to 14  of the drawings, the firearm  10 ′ is embodied as a pistol according to a second preferred embodiment of the present invention. The firearm, both the rifle  10  and the pistol  10 ′ as embodied in the first and second preferred embodiments respectively, is configured for performing firing operation has a magazine receiving cavity  12 ,  12 ′ configured and arranged for receiving the magazine  20 ,  20 ′ of the present invention therein for supplying ammunition cartridges  30 ,  30 ′ for the firearm  10 ,  10 ′ to fire. 
     In particular, the magazine  20 ,  20 ′ in the present invention is distinguished from the conventional magazine that comprises the auto-releasing arrangement  210 ,  210 ′ allows an operator at the time that the last round of cartridge  30 ,  30 ′ in the magazine  20 ,  20 ′ is chambered in the firearm  10 ,  10 ′ physically, the magazine  20 ,  20 ′ automatically releases from the firearm  10 ,  10 ′ for removal such that the operator is able to reload another loaded magazine  20 ,  20 ′ while the firearm  10 ,  10 ′ is still at a firing mode, which is not only able to carry cartridges  30 ,  30 ′ for the firearm  10 ,  10 ′ but also is capable of physically informing the state of the magazine  20 ,  20 ′ to the operator during shooting. 
     As shown in  FIG. 1  and  FIG. 8  of the drawings, the firearm, as a rifle  10  or a pistol  10 ′ generally comprising an upper receiver, a barrel, a fire mechanism, an upper receiver, a bolt assembly, a bolt catch, and other necessary assemblies as those of conventional rifles and pistol, provides the magazine receiving cavity  12 ,  12 ′ for receiving the magazine  20  therein and a magazine release button  13 ,  13 ′ for locking the magazine  20 ,  20 ′ in position in the magazine receiving cavity  12 ,  12 ′. The bolt catch is arranged to selectively control the bolt assembly to lock or unlock to a firing chamber  11 ,  11 ′ which is adapted for receiving a cartridge  30 ,  30 ′ in ready-to-fire position. As shown in  FIG. 1 ,  FIG. 4 ,  FIG. 8 , and  FIG. 11 , the magazine release button  13 ,  13 ′ configured on a side of the firearm  10 ,  10 ′ is linked with a magazine catch  131 ,  131 ′ provided in the magazine receiving cavity  12 ,  12 ′, wherein a resilient member (not shown) is provided between the magazine release button  13 ,  13 ′ and the magazine catch  131 ,  131 ′ such that the magazine release button  13 ,  13 ′ is retained by the resilient member to protruded out of the firearm  10 ,  10 ′ while the magazine catch  131 ,  131 ′ is configured to removably retain the magazine  20 ,  20 ′ in the magazine receiving cavity  12 ,  12 ′. When the magazine release button  13 ,  131 ′ is actuated, for example being pressed down by the operator, the magazine catch  131 ,  131 ′ is driven to release the retaining of the magazine  20 ,  20 ′ in the magazine receiving cavity  12 ,  12 ′. 
     In order to fire the rifle  10  or pistol  10 ′, the magazine  20 ,  20 ′ loaded with a predetermined number of cartridges  30 ,  30 ′ is inserted into the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′ and a series of corresponding operations should be performed to load the uppermost cartridge  30 ,  30 ′ of the cartridges  30 ,  30 ′ loaded in the magazine  20 ,  20 ′ into the firing chamber  11 ,  11 ′ of the firearm  10 ,  10 ′ properly. In particular, after the firearm  10 ,  20 ′ is discharged, the bolt assembly automatically moves rearwards due to the recoil force from the firing which allows a spent cartridge casing to be ejected and another uppermost cartridge  30 ,  30 ′ in the magazine  20 ,  20 ′ to be uploaded from magazine  20 ,  20 ′ and chambered in the firing chamber  11 ,  11 ′ by means of, for example, a recoil spring which automatically returns the bolt assembly forward and pushes and loads the cartridge  30 ,  30 ′ into the firing chamber  11 ,  11 ′. Then the bolt assembly is also retractable which cocks the hammer and initially readies the firearm  10 ,  10 ′ for semi-automatic operation. Accordingly, no matter the rifle or the pistol a semi-automatic or an automatic firearm, the firearm  10 ,  10 ′ would not generate any signals to inform the state of the magazine  20 ,  20 ′, such as whether the magazine  20 ,  20 ′ is empty or not, until the last cartridge  30 ,  30 ′ of the magazine  20 ,  20  fed in the firing chamber  11 ,  11 ′ is fired out. Consequently, when operating the conventional firearm  10 ,  10 ′ at intensive occasions, such as a gunfight or battle, the operator may not realize the magazine  20 ,  20 ′ is fully fired out and empty until the firearm  10 ,  10 ′ is unable to fire mechanically. 
     However, as to conventional rifles and pistols, when the magazine  20 ,  20 ′ is empty and the last cartridge  30 ,  30 ′ in the firing chamber  11 ,  11 ′ is fired out, the operator has to perform a series of reloading operations to replace another loaded magazine  20 ,  20 ′ with the current empty magazine  20 ,  20 ′ in the magazine receiving cavity  12 ,  12 ′. In other words, when there is no cartridge in the firearm  10 ,  10 ′, the operator is required to actuate the magazine release button  13 ,  13 ′ provided on a side of the firearm  10 ,  10 ′ to depress the magazine catch  131 ,  131 ′ to release the retaining and locking of the empty magazine  20  and to detach and remove the empty magazine  20 ,  20 ′ from the magazine receiving cavity  12 ,  12 ′, and then insert another loaded magazine  20 ,  20 ′ into the magazine receiving cavity  12 ,  12 ′. Finally, the operator has to depress the slide stop, throwing the slide forward, stripping an uppermost cartridge  30 ,  30 ′ of the cartridges  30 ,  30 ′ loaded in the magazine  20 ,  20 ′ and chambering it in the firing chamber  11 ,  11 ′ before the operator can fire again. That causes a period of fireless interval during which the operator has no cartridge to fire and is virtually weapon-less and in great danger. 
     Accordingly, in order to eliminate such firing blank during replacing magazine, the magazine  20 ,  20 ′ of the present invention, comprises an auto-releasing arrangement  210 ,  210 ′ configuring to indicate the state of the magazine  20 ,  20 ′ physically and to remind the operator to replace the empty magazine  20 ,  20 ′ with another loaded magazine  20 ,  20 ′ at the last timing that the last cartridge  30 ,  30 ′ in the magazine  20 ,  20 ′ is chambered in ready-to-fire position, so that the operator can replace another loaded magazine  20 ,  20 ′ while the firearm  10 ,  10 ′ is still ready for firing. After the new-loaded magazine  20 ,  20 ′ is replaced and engaged in the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′, it is capable of firing continuously again. 
     More specifically, as shown in the  FIG. 3  and  FIG. 10  of the drawings, the magazine  20 ,  20 ′ of the present invention comprises a magazine casing  21 ,  21 ′ having a magazine catch slot  24 ,  24 ′ provided in a side thereof, a cartridge follower  22 ,  22 ′, a resilient element  25 ,  25 ′, and the auto-releasing arrangement  210 ′,  210 ′. The magazine casing  21 ,  21 ′ has a cartridge chamber  232 ,  232 ′ defined therein and a cartridge opening  233 ,  233 ′ formed communicating with the cartridge chamber  232 ,  232 ′ to allow cartridges  30 ,  30 ′ receiving in and feeding out therethrough. The cartridge follower  22 ,  22 ′ is mounted in the cartridge chamber  232 ,  232 ′ and supported by the resilient element  25 ,  25 ′ which is housed in the cartridge chamber  232 ,  232 ′ and extended between a base  26 ,  26 ′ of the magazine casing  21 ,  21 ′ and the cartridge follower  22 ,  22 ′ for providing a resilient force against the cartridge follower  22 ,  22 ′ towards the cartridge opening  233 ,  233 ′. Accordingly, the cartridges  30 ,  30 ′ fed in the cartridge chamber  232 ,  232 ′ are guided one after one between the cartridge follower  22 ,  22 ′ and the cartridge opening  233 ,  233 ′ that maintains an uppermost cartridge of the cartridges  30 ,  30 ′ housed in the magazine  20 ,  20 ′ at a position of the cartridge opening  233 ,  233 ′ for loading and chambering into the firing chamber  11 ,  11 ′ by manually feeding in or by the returning of the bolt assembly forward and pushing to load the uppermost cartridge  30 ,  30 ′ into the firing chamber  11 ,  11 ′ during each firing. The magazine catch slot  24 ,  24 ′ is formed at a side wall of the magazine casing  21 ,  21 ′ and configured to releasably engage with the magazine catch  131 ,  131 ′ of the firearm  10 ,  10 ′ in such a manner to retain the magazine  20 ,  20 ′ in the magazine receiving cavity  12 ,  12 ′ in a locking state after the magazine  20 ,  20 ′ is inserted into the magazine receiving cavity  12 ,  12 ′ accordingly. 
     According to the first and second preferred embodiments of the present invention, the auto-releasing arrangement  210 ,  210 ′ is provided with the cartridge follower  22 ,  22 ′ and arranged in such a manner that the auto-releasing arrangement  210 ,  210 ′ is moved along with the up-and-down movement of the cartridge follower  22 ,  22 ′. In particular, when the magazine  20 ,  20 ′ is inserted into the magazine receiving cavity  12 ,  12 ′ until the magazine catch  131 ,  131 ′ of the firearm  10 ,  10 ′ is inserted and retained in the magazine catch slot  24 ,  24 ′ by the resilient member (not shown) so as to retain and lock the magazine  20 ,  20 ′ in position, wherein the resilient member will push and retain the magazine catch  131 ,  131 ′ to be engaged with the magazine catch slot  24 ,  24 ′ to functionally create an interlock which prevents the magazine  20 ,  20 ′ from being removed during firing. To release the magazine  20 ,  20 ′, the operator may manually actuate the magazine release button  13 ,  13 ′ to compress the resilient member and drive the magazine catch  131 ,  131 ′ outwardly away from the magazine catch slot  24 ,  24 ′, so that the magazine catch  131 ,  131 ′ is disengaged with the magazine catch slot  24 ,  24 ′ of the magazine  20 ,  20 ′ to release the locking of the magazine  20 ,  20 ′ within the magazine receiving cavity  12 ,  20 ′ for removal of magazine  20 ,  20 ′. 
     According to the first and second preferred embodiments of the present invention, when one or more cartridges  30 ,  30 ′ are loaded in the magazine  20 ,  20 ′, as shown in  FIGS. 4-5  and  FIGS. 11-12 , the position of the auto-releasing arrangement  210 ,  210 ′ is remained lower than the magazine catch slot  24 ,  24 ′ and thus the magazine  20 ,  20 ′ remains being retained in the magazine receiving cavity  12 ,  12 ′ due to the engagement of the magazine catch  131 ,  131 ′ and the magazine catch slot  24 ,  24 ′. However, when the last cartridge  30 ,  30 ′ of the magazine  20 ,  20 ′ is loaded into the firing chamber  11 ,  11 ′ of the firearm  10 ,  10 ′, as shown in  FIG. 6  and  FIG. 13 , the empty magazine  20 ,  20 ′ is pushed upwards to its uppermost position along with the spring-loaded cartridge follower  22 ,  22 ′ by the resilient element  25 ,  25 ′ that the auto-releasing arrangement  210 ,  210 ′ is driven by the cartridge follower  22 ,  22 ′ to align with and depress the magazine catch  131 ,  131 ′ towards and to disengage with the magazine catch slot  24 ,  24 ′ to release the magazine  20 ,  20 ′ from the magazine receiving cavity  12 ,  12 ′. The detaching of the magazine  20 ,  20 ′ is also a signal informing the operator it is the time to replace another loaded magazine  20 ,  20 ′. 
     It worth mentioning that when the magazine  20 ,  20 ′ is detached from the magazine receiving cavity  12 ,  12 ′ by means of the auto-releasing arrangement  21 ,  21 ′, the last cartridge  30 ,  30 ′ of the previous magazine  20 ,  20 ′ is just chambered into the firing chamber  11 ,  11 ′ in a ready-to-fire mode. In other words, the firearm  10 ,  10 ′ is still at a firing mode when the auto-releasing arrangement  21 ,  21 ′ detaches the magazine  20 ,  20 ′ from the magazine catch  131 ,  131 ′ of the firearm  10 ,  10 ′. Therefore, the operator is able to fire while replacing the magazine  20 ,  20 ′ and continue to fire at once after the empty previous magazine  20 ,  20 ′ is replaced by another loaded magazine  20 ,  20 ′. 
     According to the first preferred embodiment of the present invention, as shown in  FIGS. 4-6  of the drawings, the auto-releasing arrangement  210  comprises an actuator  211  which is a protrusion member integrally and protrudedly formed at a side wall of a lower portion of the cartridge follower  22 . According to the second preferred embodiment of the present invention, as shown in  FIGS. 11-13  of the drawings, the auto-releasing arrangement  210 ′ comprises an actuator  211 ′ which is a protrusion member integrally and protrudedly formed at a side wall of an upper portion of the cartridge follower  22 ′. 
     According to the first and second preferred embodiments of the present invention, the actuator  211 ,  211 ′ is arranged in such a manner that, when the last cartridge  30 ,  30 ′ of the magazine  20 ,  20 ′ is loaded into the firing chamber  11 ,  11 ′ of the firearm  10 ,  10 ′, the auto-releasing arrangement  210 ,  210 ′ is moved to align with the magazine catch slot  24 ,  24 ′ of the magazine  20 ,  20 ′ and the actuator  211 ,  211 ′ is just positioned at the magazine catch slot  24 ,  24 ′ to bias against and depress the magazine catch  131 ,  131 ′ to disengage with the magazine catch slot  24 ,  24 ′ so as to release the magazine  20 ,  20 ′ from the magazine receiving cavity  12 ,  12 ′ mechanically, as shown in  FIG. 7  and  FIG. 14 . At the same time, the releasing of the magazine  20 ,  20 ′ from the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′ sends an explicit signal to the operator, indicating that the last cartridge  30 ,  30 ′ of the magazine  20 ,  20 ′ has been chambered into the firing chamber  11 ,  11 ′ and it is time to replace the magazine  20 ,  20 ′ without uninterrupted firing. 
     It worth mentioning that a sound of snap is generated as the magazine  20 ,  20 ′ is released and detached from the magazine catch  131 ,  131 ′, such that the auto-releasing arrangement  21 ,  21 ′ further provides an acoustical signal to inform the operator a timing to replace the magazine  20 ,  20 ′ at the same time, as shown in  FIG. 7  and  FIG. 14 . Therefore, even if the operator is highly focused on on-site observation and shooting, he would be aware of the empty state of the magazine  20 ,  20 ′ and the right time to replace the magazine  20 ,  20 ′ through this reminding signal generated by the auto-releasing arrangement  21 ,  21 ′ of the magazine  20 ,  20 ′. 
     Moreover, according to the first and second preferred embodiments of the present invention, as shown in  FIG. 3  and  FIG. 10  of the drawings, the actuator  211 ,  211 ′ has a cambered outer surface  2110 ,  2110 ′ for ease of the movement of the auto-releasing arrangement  210 ,  210 ′ relative to the magazine catch slot  24 ,  24 ′. As mentioned above, when the last cartridge  30 ,  30 ′ of the magazine  20 ,  20 ′ is loaded into the firing chamber  11 ,  11 ′ of the firearm  10 ,  10 ′, the actuator  211 ,  211 ′ is aligned with and extended into the magazine catch slot  24 ,  24 ′ to depress against the magazine catch  131 ,  131 ′ until the magazine catch  131 ,  131 ′ disengages the magazine catch slot  24 ,  24 ′ to release the magazine  20 ,  20 ′ for removal from the magazine receiving cavity  12 ,  12 ′. In particular, the cambered outer surface  2110 ,  2110 ′ of the actuator  211 ,  211 ′ substantially reduces the friction between the actuator  211 ,  211 ′ and the inner walls of the magazine catch slot  24 ,  24 ′, such that the actuator  211 ,  211 ′ is able to move smoothly in and out of the magazine catch slot  24 ,  24 ′ to disengage the magazine catch  131 ,  131 ′. 
     In order to further prevent any collision between the auto-releasing arrangement  210 ,  210 ′ and the magazine catch slot  24 ,  24 ′, the actuator  211 ,  211 ′ has a thickness equal to or slight smaller than a height defined between an upper edge  241 ,  241 ′ and a lower edge  242 ,  242 ′ of the magazine catch slot  24 ,  24 , such that when the actuator  211 ,  211 ′ of the auto-releasing arrangement  210 ,  210 ′ is moved towards the magazine catch slot  24 ,  24 ′ as the cartridges  30 ,  30 ′ being loaded and fired out in turns, the portion of the cartridge chamber  232 ,  232 ′ below the lower edge  242 ,  242 ′ of the magazine catch slot  24  provides sufficient space for the auto-releasing arrangement  210 ,  210 ′ to move therebelow without any unwanted collision, and the actuator  211 ,  211 ′ of the auto-releasing arrangement  210 ,  210 ′ is blocked by the lower edge  242 ,  242 ′ of the magazine catch slot  24 , as shown in  FIGS. 4-6  and  FIGS. 11-13  of the drawings. 
     Further, as shown in  FIGS. 4-6  and  FIGS. 11-13  of the drawings, an inner wall of the magazine casing  21 ,  21 ′ at the portion below the lower edge  242 ,  242 ′ of the magazine catch slot  24 ,  24 ′ may be configured as an inclined surface  231 ,  231 ′ to provided an enlarged gap between the auto-releasing arrangement  210 ,  210 ′ and the inner wall of the magazine casing  21 ,  21 ′, for allowing the auto-releasing arrangement  210 ,  210 ′ to move smoothly within the cartridge chamber  232 ,  232 ′. In other words, the auto-releasing arrangement  210 ,  210 ′ and the magazine casing  21 ,  21 ′ of the magazine  20 ,  20 ′ are configured without affecting the normal cartridge-loading operation, while the auto-releasing arrangement  210 ,  210 ′ further functions as a reminder to inform the state of the magazine  20 ,  20 ′ to the operator timely. 
     The detachable magazine  20 ,  20 ′ of the first and second preferred embodiments as described above is preferred to be configured with the firearm  10 ,  10 ′ that provides the magazine receiving cavity  12 ,  12 ′ configured to fittingly receive the magazine  20 ,  20 ′ accordingly. In order to equip the auto-releasing arrangement of the present invention to the conventional magazine and firearm without any modification of the structure of the magazine, referring to  FIGS. 15 to 22 , alternative modes of the above first and second preferred embodiments of the present invention are provided. 
     Referring to  FIGS. 15 to 18 , an alternative mode of the magazine  20 A of the first preferred embodiment of the present invention is illustrated, wherein the magazine  20 A for the rifle  10  as shown in  FIG. 1  is simply constructed as the conventional magazine that comprises the magazine casing  21 , which has the cartridge chamber  232  therein, the cartridge opening  233  at one end and the magazine catch slot  24  formed at a middle portion of a side of the magazine casing  21 , the cartridge follower  22 , the resilient element  25 , and the base  26 . 
     In this alternative mode of the magazine  20 A of the first preferred embodiment, the auto-releasing arrangement  210 A is modified to comprise an actuator  211 A which is an elongated resilient element (such as a metal plate) having an upper end affixed to a lower portion of the cartridge follower  22  and a lower end extended downwardly. The actuator  211 A, which is extended in a gap formed between the inner wall of the magazine casing  21  and the resilient element  25 . The actuator  211 A further comprises a protrusion member  2110 A integrally and outwardly protruded at the lower end thereof. The positions of the actuator  211 A and its protrusion member  2110 A are configured to enable the protrusion member  2110 A extending in the magazine catch slot  24  and depressing the magazine catch  131  away from the magazine catch slot  24  to release the magazine  20 A from the magazine receiving cavity  12  when the last round of cartridge  30  in the magazine  20 A is chambered in the firing chamber  11 , as shown in  FIGS. 1, 2 and 18 . 
     Accordingly, as shown in  FIG. 16 , when the magazine  20 A is loaded with cartridges  30 , the cartridge follower  22  is pressed down by the cartridges  30  to position in a lower position in the cartridge chamber  232  and carries the actuator  211 A to a lower position in the cartridge chamber  232  too while the protrusion member  2110 A is pressed by the inner wall of the magazine casing  21  inwardly. It is appreciated that since the actuator  211 A is made of a thin metal plate, a resilient ability is provided enabling the actuator  211 A to be slightly bent inwardly. 
     When one or more cartridges  30  in the magazine  20 A is discharged, the resilient element  25  drives the cartridge follower  22  to move upwards which carries the actuator  211 A to move together. As shown in  FIG. 17 , when there is a last round of cartridge  30  positioned at the uppermost position of the cartridge chamber  232  of the magazine  20 A, i.e. positioned at the cartridge opening  233 , the actuator  211 A is driven by the cartridge follower  22  to a position right below the magazine catch slot  24  while the magazine catch  131  of the firearm  10  is remained being engaged with the magazine catch slot  24 . As shown in  FIG. 18 , when the last round of cartridge  30  is chambered in the firing chamber  11  of the firearm  10 , there is no cartridge  30  left in the magazine  20 A and the cartridge follower  22  is further upwardly pushed by the resilient element  25  to the uppermost position, i.e. right at the cartridge opening  233  of the magazine  20 A, wherein the actuator  211 A is driven by the cartridge follower  22  to actuate to release the magazine  20 A from the magazine receiving cavity  12  of the firearm  10 . In particular, the protrusion member  2110 A of the actuator  211 A is driven by the cartridge follower  22  to a position right at the magazine catch slot  24 , wherein the resilient force from the inner wall of the magazine casing  21  is released and the protrusion member  2110 A pushes out to extend into the magazine catch slot  24  to depress the magazine catch  131  so as to release the engagement between the magazine catch  131  and the magazine catch slot  24 , and thus the magazine  20 A is released and detached for removal from the magazine receiving cavity  12  of the firearm (rifle)  10 , as shown in  FIGS. 7 and 18 . 
     Referring to  FIGS. 19 to 22 , an alternative mode of the magazine  20 B of the second preferred embodiment of the present invention is illustrated, wherein the magazine  20 B for the pistol  10 ′ as shown in  FIG. 8  is simply constructed as the conventional magazine that comprises the magazine casing  21 ′, which has the cartridge chamber  232 ′ therein, the cartridge opening  233 ′ at one end and the magazine catch slot  24 ′ formed at a middle portion of a side of the magazine casing  21 ′, the cartridge follower  22 ′, the resilient element  25 ′, and the base  26 ′. 
     In this alternative mode of the magazine  20 B of the second preferred embodiment, the auto-releasing arrangement  210 B is modified to comprise an actuator  211 B which is an elongated element (such as a metal plate) having at least an upper guider  2111 B protruded sidewardly at an upper portion of a side thereof and at least a lower guider  2112 B protruded sidewardly at a lower portion of the same side having the upper guider  2111 B. The actuator  211 B further has an elongated longitudinal groove  2113 B extended between the upper portion and the lower portion thereof. The actuator  211 B, which is slidably mounted and extended in a gap formed between the inner wall of the magazine casing  21  and the resilient element  25 , further comprises at least a protrusion member  2110 B integrally and sidewardly protruded at the same side having the upper guider  2111 B and the lower guider  2112 B thereof and positioned between the upper guider  2111 B and the lower guider  2112 B. The positions of the actuator  211 A and its protrusion member  2110 A are configured to enable the protrusion member  2110 A extending in the magazine catch slot  24 ′ and depressing the magazine catch  131 ′ away from the magazine catch slot  24 ′ to release the magazine  20 B from the magazine receiving cavity  12 ′ when the last round of cartridge  30 ′ in the magazine  20 B is chambered in firing chamber  11 ′, as shown in  FIGS. 8, 9 and 22 . 
     Corresponding to the upper guider  2111 B and lower guider  2112 B of the actuator  211 B, the cartridge follower  22 ′ also comprises at least a driver member  221 B protruded therefrom and configured for moving between the upper guider  2111 B and the lower guider  2112 B. In addition, the magazine casing  21 ′ further provides a pair of holders  212 B,  213 B spacedly protruded on an inner surface thereof, which are fittingly positioned in the longitudinal groove  2113 B so as to retain and mount the actuator  211 B, in an up and down slidable manner, within the gap between the resilient element  25 ′ and the inner wall of the magazine casing  21 ′. 
     It is worth mentioning that, for magazine  20 B which fit to a pistol  10 ′ for both right-hand user and left-hand user, the magazine catch  131 ′ may be provided at either side of the pistol  10 ′. Accordingly, a pair of magazine catch slots  24 ′ is formed on both sides of the magazine  20 ′ respectively and the actuator  211 B has totally a pair of protrusion members  2110 B at both sides thereof according to the alternative mode of the second embodiment as shown in  FIGS. 19-22 . 
     Accordingly, as shown in  FIG. 20 , when the magazine  20 B is fully loaded with cartridges  30 ′, the cartridge follower  22 ′ is pressed down by the cartridges  30 ′ to position in a bottom position in the cartridge chamber  232 ′, wherein the driver member  221 B of the down moving cartridge follower  22 ′ will reach and push against the lower guider  2112 B to drive the actuator  211 B to move downwards together, so that the protrusion member  2110 B is moved to position below the respective magazine catch slot  24 ′ while the protrusion member  2110 A is pressed by the inner wall of the magazine casing  21  inwardly. It is appreciated that since the actuator  211 A has the longitudinal groove  2113 B provided therein, a resilient ability is provided enabling the protrusion member  2110 B to be slightly moved towards the longitudinal groove  2113 B. 
     When one or more cartridges  30 ′ in the magazine  20 B is discharged, the resilient element  25 ′ drives the cartridge follower  22 ′ to move upwards until the protrusion member  2110 B of the actuator  211 B reaches the upper guider  2111 B, and then any further upward movement of the cartridge follower  22 ′ will drive the actuator  211 B to move upwards together while the magazine catch  131 ′ of the firearm  10 ′ is remained being engaged with the magazine catch slot  24 ′. As shown in  FIG. 21 , when there is only a last round of cartridge  30 ′ positioned at the uppermost position of the cartridge chamber  232 ′ of the magazine  20 B, i.e. positioned at the cartridge opening  233 ′, the actuator  211 B is driven by the cartridge follower  22 ′ upwards to a position that the protrusion member  2110 B of the actuator  211 B is positioned right below the magazine catch slot  24 ′. As shown in  FIG. 22 , when the last round of cartridge  30 ′ is chambered in the firing chamber  11 ′ of the firearm  10 ′, there is no cartridge  30 ′ left in the magazine  20 B and the cartridge follower  22 ′ is further upwardly pushed by the resilient element  25 ′ to the uppermost position, i.e. right at the cartridge opening  233 ′ of the magazine  20 B, wherein the actuator  211 B is driven by the cartridge follower  22 ′ to actuate to release the magazine  20 B from the magazine receiving cavity  12 ′ of the firearm  10 ′. In particular, the protrusion member  2110 B of the actuator  211 B is driven by the cartridge follower  22 ′ to a position right at the magazine catch slot  24 ′, wherein the resilient force from the inner wall of the magazine casing  21 ′ is released and the protrusion member  2110 B pushes out to extend into the magazine catch slot  24 ′ to depress the magazine catch  131 ′ so as to release the engagement between the magazine catch  131 ′ and the magazine catch slot  24 ′, and thus the magazine  20 B is released and detached for removal from the magazine receiving cavity  12 ′ of the firearm (pistol)  10 ′, as shown in  FIGS. 8 and 22 . 
     It is worth mentioning that the magazine  20 ,  20 ′,  20 A,  20 B comprising the auto-releasing arrangement  210 ,  210 ′,  210 A,  210 B of the present invention has a module configuration, such that equipped with various magazine  20 ,  20 ′,  20 A,  20 B of the present invention, the rifle or pistol is able to fire uninterruptedly during replacing the magazines  20 ,  20 ′,  20 A,  20 B compared with conventional magazine. Moreover, the shape, the size and predetermined loading rounds of cartridge  30 ′ can be modified according to the structure and features of a specific firearm, so long as the magazine  20 ,  20 ′,  20 A,  20 B is mated with the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′. 
     Referring to  FIGS. 1 to 22  of the drawings, the present invention further discloses an auto-releasing method of the magazine  20 ,  20 ′,  20 A,  20 B for the firearm  10 ,  10 ′ for the operator, wherein the method comprises the steps of: 
     (a) driving the actuator  211 ,  211 ′,  211 A,  211 B to move along with a movement of the cartridge follower  22 ,  22 ′ mounted in the cartridge chamber  232 ,  232 ′ of the magazine casing  21 ,  21 ′ of the magazine  20 ,  20 ′,  20 A,  20 B and supported by the resilient element  25 ,  25 ′ housed in the cartridge chamber  232 ,  232 ′ and extended between the base  26 ,  26 ′ of the magazine casing  21 ,  21 ′ and the cartridge follower  22 ,  22 ′; and 
     (b) actuating the magazine catch  131 ,  131 ′ of the firearm  10 ,  10 ′ which is configured to lock the magazine  20 ,  20 ′,  20 A,  20 B inserted in the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′ in position to unlock and release the magazine  20 ,  20 ′,  20 A,  20 B for removal from the magazine receiving cavity  12 ,  12 ′ while a last cartridge of one or more cartridges  30 ,  30 ′ housed in the magazine casing  21 ,  21 ′ is leaving the magazine  20 ,  20 ′,  20 A,  20 B and chambered and loaded in the firearm  10 ,  10 ′ for firing, such that the operator of the firearm  10 ,  10 ′ is able to detach the empty magazine  30 ,  30 ′ and replace another loaded magazine  30 ,  30 ′ in the magazine receiving cavity  12 ,  12 ′ of the firearm  10 ,  10 ′ while there is still one cartridge  30 ,  30 ′ being chambered and ready for firing. 
     In addition, after the step (b) of the auto-releasing method of the present invention, the auto-releasing method further comprises a step (c) of generating a snap sound at the time when the last cartridge  30 ,  30 ′ in the magazine  20 ,  20 ′,  20 A,  20 B is chambered and the magazine catch  131 ,  131 ′ is released by the actuator  211 ,  211 ′,  211 A,  211 B. 
     One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
     It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.