Abstract:
A media magazine container utilizes a recirculating latch mechanism that makes minimal use of a solenoid and includes a safety door. The latch mechanism includes a contoured latch arm with a configured opening and a shoulder, a slider moving in a slider track and coupled to the latch arm, and a restoring device, such as a spring, for providing a counteractive force. The mechanism latches a magazine into the container by capturing magazine pins in the shoulder of the latch arm. The magazine can be easily unlatched by forcing the latch arm downward with an actuating device, causing the slider and configured opening to interact. As the magazine is extracted from the container, the slider and configured opening interact in such a manner that when the magazine is fully extracted the latch arm is back to the original position where it first received the magazine, and is ready to receive another. A safety door blocks passage to any objects entering the container other than a media magazine. The latch mechanism can further actuate an external access door.

Description:
TECHNICAL FIELD 
     The present invention relates to storage devices for holding large numbers of removable media, more particularly to media magazine latch mechanisms for such storage devices. 
     BACKGROUND 
     In the computer industry many types of devices are used in conjunction with computers for storing and managing data. One such device is a library having large numbers of storage slots for storing removable media. Media generally comprise a magnetic or optical material in the shape of a disk or tape, store computer readable data, and are surrounded by a plastic housing. A library user, generally a robot arm, sometimes called a picker or MTA, inserts and extracts media from the library containers. 
     To allow the users of libraries easy access to their media, devices in use today have media magazines. A media magazine is a removable container that holds one or more pieces of media so as to allow a user to insert the media into the library or to remove it from the library. To provide access to the media magazine, many libraries in use today have an access door, a latch mechanism, and a solenoid. An access door is a door at the front of the library that must be moved up, down, or aside to provide passage to the media magazine as it is inserted or extracted from the library, thus allowing access to the magazine when opened. Another common element of many libraries is a latch mechanism. Once a media magazine is inserted into the library, it engages a latch mechanism which holds the media magazine in place inside a container. Yet another common element of many libraries is a solenoid unit, including a solenoid coil and a metal plunger. The solenoid coil produces a strong magnetic force when a current is passed through it, which magnetic force manipulates the metal plunger to provide force and motion to the mechanism. Solenoids are often used to release the media magazine free from the latch mechanism so that the media magazine can be removed. 
     The overall design of conventional latch mechanisms can be very complex. Latch mechanisms used today utilize numerous small mechanical and electronic components, such as electronic sensors or motors. Those many small mechanical and electronic components can easily add significant product costs. A complex design, with many parts and components, also increases the possibility of malfunction and difficulty of repair. Furthermore, a complex design may even require the use of software or advanced timing circuitry. 
     In addition to complex designs of latch mechanisms, some overall library designs overutilize solenoids in conjunction with the latch mechanism. More specifically, some designs require that a solenoid maintain a current within its coil for prolonged periods of time while waiting for a user to remove a magazine, while other designs utilize more than one solenoid when latching or unlatching the magazine into the library. These prolonged or excessive uses of solenoids increase power consumption and potentially reduce product life. 
     Yet another disadvantage of current libraries is the lack of protection to internal components provided by a safety door. A safety door can block access to foreign objects, such as dust, as well as providing protection to the user from contact with internal components. 
     Thus, contemporary libraries utilize unnecessarily complex and expensive latch mechanisms, overutilize solenoids, and provide little to no protection to internal parts beyond the limited function of an access door. Therefore, there exists a need for a library that utilizes a latch mechanism that is simple, efficient, and reliable in design and utilizes fewer costly, power consuming parts or circuitry; that makes limited use of solenoids; and that provides protection to internal parts. 
     SUMMARY OF THE INVENTION 
     The present invention provides solutions to the disadvantages of current storage devices. A media magazine container, according to the invention, has a recirculating latch mechanism that makes minimal use of a solenoid and includes a safety door. An exemplary embodiment of the latch mechanism includes a contoured latch arm with a configured opening and a shoulder; a slider moving in a slider track and coupled to the latch arm; and a restoring device, such as a spring, for providing a counteractive force. As a magazine is inserted into the container, it encounters the latch arm in a position ready to receive it. The magazine then slides along the contour of the latch arm, forcing it downward and causing the configuration in the latch arm to interact with the slider. The interaction between the slider and configured opening controls the movement of the latch arm, which movement of the latch arm guides the magazine toward the latch arm shoulder. As the magazine moves further into the container, the spring lifts the arm upward keeping the magazine in constant contact with the arm contour, and when the magazine reaches the shoulder in the latch arm, the magazine becomes locked in place. The magazine can be easily unlatched by forcing the latch arm downward causing the slider and configured opening to interact. As the magazine is extracted from the container, the slider and configured opening interact in such a manner that when the magazine is fully extracted, the latch arm is back to the original position where it first received the magazine, and is ready to receive another. 
     One aspect of the exemplary embodiment includes a detaching means, such as a solenoid or a mechanical lever, to assist in the unlatching of the magazine. The design of the latch mechanism allows the magazine to be extracted by a simple, momentary use of the detaching means which forces the latch arm downward long enough for the magazine to detach from the latch arm shoulder. Interaction between the slider and configured opening prevents the latch arm from locking the magazine in place again. If the detaching means is a solenoid, a momentary use allows for very limited power consumption. 
     Another aspect of the exemplary embodiment includes a safety door and where the latch mechanism can actuate both the safety door and an access door. The latch mechanism includes a latch arm with an end and a stroke. The end connects to an access door via an access door coupling and the stroke connects to a safety door via a safety door coupling. The design of the latch mechanism actuates the access door and safety door at proper times during insertion and extraction of the magazine, providing security to the internal parts of the container. 
     The advantages of the present invention will become apparent to those skilled in the art as they consider the following detailed description and its accompanying drawings. 
    
    
     THE DRAWING 
     FIG. 1 shows a library including a latch mechanism according to the present invention. 
     FIG. 1A shows a typical media magazine for the library of FIG.  1 . 
     FIG. 1B shows the media magazine of FIG. 1A inserted into the container of FIG.  1 . 
     FIG. 2 is a side view of the container of FIG.  1 . 
     FIGS. 2A-2G are a series of time-lapse views showing the operation of the latch mechanism shown in FIG.  2 . 
     FIG. 3 is a cut away rear view of the container of FIG.  1 . 
     FIG. 4 is perspective of the container of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     The following detailed description describes the present invention in sufficient detail to enable those skilled in the art to understand and utilize the invention. However, it must be understood that other embodiments exist and that changes may be made to the various embodiments of the invention without departing from the spirit and scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the claims. 
     FIG. 1 shows a library  100  comprising a container  105 , possessing a holding mechanism, such as a magazine latch  200 , an access door  400  (shown in FIG. 4) at the rear area  106  of the container, and a media magazine  150  (shown in the latched position). The library  100  is of any kind typically used in the industry today where an insertion/extraction device  130 , such as a robot picker-arm, inserts and removes the media. The library  100  is of no particular shape or size, and the number of containers  105  in the library can vary. The library  100  is used to house media within storage slots  109 , and has a container  105  that holds a media magazine  150 . A container  105  can receive a typical magazine  150  with magazine pins  155 . The magazine pins  155  can slide into the magazine track  110  as shown in FIG.  2 . As a magazine  150  is pushed into, or pulled out of, the container  105 , the magazine pins  155  engage the latch mechanism  200  that unlocks a safety door  300  (shown in FIG.  3 ), allowing the magazine  150  to be fully inserted into the container  105 . Thus, unless a magazine  150  is inserted into the container  105 , the safety door will not unlock nor open. When the magazine  150  is fully inserted, the safety door  300 , swings backward on safety door hinges  330 . 
     FIG. 2 is a side view perspective of one of the containers  105  of FIG. 1 showing the multiple parts of an exemplary embodiment of a latch mechanism  200  including a latch arm  210 , a slider  220 , an actuator  240 , and a restorer  230 . The latch arm  210  includes an end  212 , a stroke  214 , a configured opening  216 , a shoulder  218 , and a contour  219 . The slider  220  rides in a slider track  225  and moves side to side within its track  225  as a function of both the shape of the configured opening  216  and the up and down movements of the latch arm  210 . The slider  220  is connected to the configured opening  216  by a slider coupler, exemplified in FIG. 2 as a slider pin  223 . 
     When a magazine  150  is inserted into the magazine track  110  on the container  105 , the magazine pins  155  ride along the contour  219  of the latch arm  210  pushing the latch arm  210  downward as it rotates about a pivot point  217 . The downward pushing force caused by the magazine pins  155  riding along the contour  219  is counterbalanced by the restoring mechanism, restorer  230 , which pulls up on the latch arm so that the magazine pins  155  and the contour  219  maintain constant contact. The restorer  230  in the figure is depicted by a spring, but could be any mechanism that provides an upward force to the latch arm  210 , such as a pair of magnets, a tensioned pulley system, or a taut rubber strip. Additionally, the restorer  230  here depicted is connected to the stroke  214  of the latch arm  210 ; however, it can be connected to other places on the latch arm  210 , for instance, at the pivot point  217 . The restorer  230  could also be a tension or torsion device connected to the pivot point  217  causing resistance to the rotation of the latch arm  210 , essentially providing a counteracting force to the downward force of the magazine pins  155 . 
     As the magazine  150  is further pushed along the magazine track  110 , the magazine pins  155  eventually move past the contour  219  into the shoulder  218  of the latch arm  210  latching the magazine  150 . The latched magazine pins are depicted as  155 ′. The shape of the shoulder  218  will not allow the latched magazine pins  155 ′ to move back out of the magazine track  110  until the latch arm  210  is detached. 
     The actuator  240  is a mechanism that provides a thrust to the latch arm  210  to detach a latched magazine. In the figure, the actuator  240  is depicted as a solenoid providing a downward thrust; however, the actuator can be anything that provides a thrust, such a mechanical lever arm. Also, although the latch arm  210  must be forced downward, the actuator  240  itself does not have to thrust downward; it could be attached to the lever arm from below, thus providing a downward pull instead of a downward thrust. When the actuator  240  forces the latch arm  210  downward, the slider  220 , slider pin  223  and configured opening  216  interact in a manner that prevents the shoulder  218  from retaining the magazine pins  155 ′, and thus the magazine pins  155  are released and the magazine  150  is ready to be extracted from the container  105 . 
     Other elements may be added to this design to improve efficacy of its operation. For instance, electronic sensors  260  could be included which monitor the position of the magazine pins  155 , 155 ′ indicating to the user by means of an LED that the magazine  150  is in a latched position. Control circuitry and components may also be added to synchronize the movement of the parts. 
     FIGS. 2A-2G are a series of time elapsed drawings showing the interaction of some of the parts of the latch mechanism of FIG. 2 during insertion and extraction of the magazine. Shown in each drawing  2 A- 2 G are the interacting positions of the slider  220 , slider pin  223 , and configured opening  216 . The exemplary configured opening  216  is divided into several portions: left side  216 L, right side  216 R, top left configured portion  216 A, center section  216 B, top center portion  216 C, and top right portion  216 D. Heavy straight arrows in some of the figures indicate direction of movement. 
     FIG. 2A depicts the position of the slider  220 , slider pin  223  and configured opening  216  before the magazine  150  is inserted into the magazine track  110  of FIG.  2 . The slider pin  223  begins at the bottom most portion of the configured opening  216 . As the magazine  150  is inserted and the magazine pins  155  are pushed along the latch arm contour  219 , FIG. 2B shows how the configured opening  216  moves downward, causing the latch pin  223  to be positioned along the left side  216 L. When the magazine pins  155  enter the shoulder  218 , Figure C shows the configured opening  216  moving upward, causing the latch pin  223  to be positioned on the left side  216 L. The latch pin  223  will remain is the final position depicted in FIG. 2C until the actuator  240  forces the latch arm  210  downward. 
     When the actuator  240  forces the latch arm  210  downward with enough force, FIG. 2D shows how the configured opening  216  will move downward enough so that the slider pin  223  will encounter the top left configured portion  216 A. The top left configured portion  216 A has a shape that will force the slider pin  223  sideways, thus forcing the slider  220  sideways. When the actuator  240  stops forcing the latch arm  210  downward, the restorer  230  forces the latch arm  210  back up, thus causing the configured opening  216  to move upward, as depicted in FIG.  2 E. However, since the slider pin  223  moved sideways into the top left configured portion  216 A, as the configured opening  216  moves upward the slider pin  223  encounters the center piece  216 B. When the slider pin  223  encounters the center piece  216 B, the latch arm  210  is restricted from moving upward, and the magazine pins  155  will not latch back into the shoulder  218 . 
     When the magazine  150  is later extracted, it again rides the contour  219  of the latch arm  210 , thus forcing the latch arm  210  downward, causing the configured opening  216  to move downward causing the slider pin  223  to move upward and encounter top center configured portion  216 C, as depicted in FIG.  2 F. As the magazine pins  155  move forward along the contour  219  on their way out of the container  105 , the configured opening  216  continues to move downward causing the slider pin  223  to continue to move upward until it encounters top right configured portion  216 D. As the slider pin  223  moves sideways as shown in FIGS. 2D-2F, the slider  220  also moves sideways, until the slider pin  223  is in the final position shown in FIG.  2 F. When the magazine  150  is extracted to the point where the magazine pins  155  no longer ride the contour  219 , then the latch arm  210  moves upward, causing the configured opening  216  to move upward, causing the latch pin  223  to move along the right side  216 R as shown in FIG. 2G, causing the slider  220  to move sideways until it again positioned as it was in FIG.  2 A. 
     As can be noted from FIGS. 2A-2G, the slider pin  223  circulates entirely around the configured opening  216  throughout the insertion, latching, and extraction of the magazine  150 . Hence, the latch mechanism is a recirculating latch, one where a member follows a closed path in a latch/unlatch cycle, but does not merely retrace itself during a single cycle. 
     FIG. 3 is a cut away, rear view of one of the containers  105  of FIG. 1 showing how the safety door  300  and latch mechanism  200  interact. The safety door  300 , connected to safety door hinges  330 , resides inside the container  105 . A latch tooth  310 , connected to the safety door  300 , is obstructed by a safety door coupling such as pin  320 , preventing the safety door  300  from swinging on its safety door hinges  330 . When a media magazine enters the container  105 , (as shown in FIG. 2) and the magazine pins  155  begin to ride along the arm contour  219 , the latch arm  210  moves downward. As a result, safety door pin  320  also moves downward so that it no longer obstructs the latch tooth  310 , thus permitting the safety door  300  to swing backward on its safety door hinges  330 . To help provide feedback to the machine as to the position of the safety door  300 , a safety door track  340  may be used in conjunction with a safety door flag  345 . The safety door flag  345  interacts with a sensor on the circuit board  343  to indicate the position of the safety door to the system. To keep the safety door  300  from swinging forward on its hinges  330 , the safety door track  340  only extends backward in a quarter arc shape. The safety door track  340  and safety door peg  345  are not necessary to the proper function of the safety door, as the principal function of the safety door is to prevent access from the front portion of the container  105 . Nevertheless, even if a safety door track  340  is not used, the safety door  300  can still be prevented from swinging forward in other ways, such as using only backward swinging safety door hinges. Additionally, the positions of the hinges  330  and track  340  need not be limited to the positions shown in FIG.  3 . The hinges could be at the bottom or side of the safety door  300  and still serve the same function; the track would only need to be rotated accordingly. 
     FIG. 4 is an angled perspective of one of the containers  105  of FIG. 1 showing how the access door  400  can be actuated by the latch mechanism  200 . The access door  400  is connected to an access door mechanism  420  which causes the access door  400  to open and close. An access door latch  410  is coupled to the door mechanism  420 . When the latch arm  210  is thrust downward by the actuator  240 , the latch arm end  212  contacts latch  410 , actuating access door mechanism  420 . 
     The above detailed description is illustrative. It is not intended to be restrictive. Upon review of the above detailed description, one skilled in the art will no doubt see many other embodiments within the full scope and nature of the invention. Therefore, the full scope of the invention should be construed in reference to the language of the claims and all equivalents thereof.