Foldable mobile station with non-cylindrical hinge

A novel folding design for a mobile station is disclosed that provides a stylish design, a simplified assembly, and relatively few parts. The improved foldable mobile station comprises a flexible front cover, multiple functional units coupled together by a folding hinge and a tension unit. The tension unit provides a compressive force to the pivotally attached functional units thereby biasing the foldable mobile station between open and folded positions.

FIELD OF THE INVENTION

The present invention relates generally to mobile-stations, and more specifically to a mobile station having a folded design encompassing an external tension device.

BACKGROUND OF THE INVENTION

The manufacture and design of today's mobile stations (also known as mobile phones, PDAs, pagers and the like) are constantly evolving. Early mobile station designs were necessarily large and bulky. The radio communications equipment and battery units necessary for their operation, generally were carried in one oversized unit; although in at least one early and cumbersome design the unit was actually divided into two pieces which were then connected by a power cable. Advances in integrated circuitry and electricity storage technology have enabled mobile station designers to create smaller and smaller devices. These instruments are not only lighter, but also less cumbersome and easier to transport. For example, mobile stations are no longer required to be permanently installed in automobiles or connected to bulky separately-carried battery packs. Essentially, today's smaller, more useful mobile stations have simply become more fashionable.

Unfortunately, several drawbacks have followed this new fashionability and convenience. For example, the increased mobility of today's mobile stations has the unintended drawback of subjecting the mobile station to an ever-increasing number of potentially damaging environments. For modern day consumers, these environments include pockets, briefcases, purses, gym bags, glove compartments and toolboxes where the delicate components of the mobile station could potentially contact harmful solid objects and be subjected to moisture. To make matters worse, market forces continue to drive mobile stations smaller, therefore, making it more difficult to protect the sensitive mobile station componentry with heavy-duty structural reinforcements. Accordingly, modern mobile stations are gradually becoming more vulnerable to damage.

This risk of damage is exacerbated by the number of externally accessible components that are provided on modern mobile phones. One of the most prominent of these components is the visual display. Initially, such displays were limited to small, light emitting diodes (LEDs) that indicated whether the phone was on or whether a call was in progress. Gradually, more advanced LED displays were developed that were capable of displaying a dialed telephone number, the current time, or other simple information. More recently, liquid crystal displays (LCDs) have become commonplace. An LCD is made by sandwiching an electrically sensitive liquid-crystal material between two very thin pieces of glass or other transparent materials. They are, therefore, easily susceptible to damage by even a relatively minor impact. Despite the hard, transparent cover or similar protective device, generally added to limit this vulnerability, LCDs remain one of the most easily damaged components in modern mobile stations.

One solution offered to provide greater protection for modern mobile stations is the bifold design. A bifold mobile station is one-that may be, generally speaking, folded in half. That is, the instrument is typically made up of at least two parts that are electrically connected together, each part housing a portion of the mobile station's internal components. For the purposes of this application, the term “folded in half” is used in a general sense, that is, the two “halves” are not necessarily equal in size. There may even be more than two “halves” although such a design is not typical. Traditionally, the two halves of a mobile station are held together by a hinge that is “opened” when the device is used. Opening the mobile station in a clam-shell type fashion, reveals its LCD and keypad, which would otherwise remain folded inside the unit when closed for storage. Foldable mobile stations may be safely tucked into a pocket or purse, or clipped to a user's belt, while the device's most impact-sensitive components are protected by a hard plastic shell.

FIGS. 1A,1B, and1C depict a folded mobile station according to the known prior art. Specifically shown, is a mobile station100having a first portion110and a second portion150. The first portion110houses an LCD115. The LCD115is visible through, and protected by, a clear plastic cover117. A speaker port120is comprised of a series of small openings formed in first portion110, and lies adjacent to an internal speaker (not shown) that is also housed by the first portion110. Further, the first portion110also typically includes circuitry for driving the LCD115and the internal speaker (not shown).

The second portion150of a conventional mobile station100generally includes a microphone port155that is adjacent to an internal microphone (not shown). A keypad160is also provided that is comprised of a series of keys extending through a plurality of openings from an otherwise internally disposed key mat. As with the first portion110, the second portion150of mobile station100also houses the internal circuitry associated with the above described microphone and keypad. An antenna for facilitating radio frequency (RF) communications may be located in either the first portion110or the second portion150, or may be distributed between them. Mobile station batteries (not shown) are typically stored in the second portion150, due to the limited space available in the first portion110as a result of the LCD115and speaker120placement. An external power supply (not shown), such as an AC adaptor, may be connected through a power port140. Similarly, external headphones (not shown) may be connected to the mobile station100at the external-device port145.

Conventional folding mobile stations100use a cylindrical hinge175similar to a standard door hinge, to bind the first portion110to the second portion150. Manufacturing mobile stations having hinges of this type requires a complex assembly process wherein an axle or pin180is inserted into the hinge and a flexible ribbon cable185is then awkwardly wrapped around it. Typically, conventional mobile stations100also include a pre-assembled detent mechanism184that holds the station in open and folded positions.

FIG. 1Cillustrates a conventional folding mobile station hinge as described above. The hinge175is formed from hinge members176and177that extend from the first portion110and the hinge members178and179that extend from the second portion150. The two sections are held together by a hinge pin180that extends through openings formed in hinge members176through179. If placed in the orientation illustrated inFIG. 1A, the mobile station100is generally ready to operate. When the mobile station is thus “opened,” the user has access to the keypad160and can conveniently place the speaker port120and microphone port155in a position for voice communication. The mobile station100may also be “closed” by folding the first portion110to meet the second portion150in a clam-shell action as indicated by the arrow.FIG. 1Billustrates a known mobile station100in the folded position. Advantageously, the first portion110and the second portion150close in such a manner as to protect the keypad160and LCD115. Generally speaking, known mobile stations100cannot be used in a folded configuration, although such functionality may be achieved by employing an external microphone and speaker (not shown). Such devices are often used in ‘hands-free’ operation, and are readily connected through an external-device port145. As alluded to above, the folded design of modern mobile stations100distinguish them from their predecessors by accommodating safe storage on belts, in pockets, purses, or glove compartments without subjecting the sensitive internal components to damage from keys or other objects frequently encountered in such environments.

As should by now be apparent, folded mobile stations possess features that are both useful and desirable to consumers. In addition to the durability improvements discussed above, many users prefer folding designs over others, based on pure aesthetics. Despite the above improvements, the conventional folding design depicted inFIGS. 1A and 1Bis still not optimum. Like many early designs, conventional folded mobile station designs employ overly complex hinges of the type illustrated inFIG. 1Cand are accordingly costly to manufacture. Additionally, the known cylindrical hinge design discussed above provides little or no latitude for alteration or aesthetic improvement.

In light of the foregoing, it would be highly desirable to produce an improved foldable mobile station having a minimum of internal hinge components while maintaining a robust, durable design. Furthermore, it would be desirable to provide a hinge that is relatively simple to assemble and serves to compliment the overall aesthetic appeal of the mobile station.

BRIEF SUMMARY OF THE INVENTION

The above and other objects are met and other advantages are achieved by the present invention, which includes a novel folding design for a mobile station accommodating an improved hinge design having fewer parts and a simpler, more cost effective assembly. Specifically, the improved mobile station according to the present invention, includes a flexible front cover, and multiple functional units coupled together by an improved hinge that is biased by an external tension unit. More precisely, the tension unit biases the functional units toward open and folded positions, while freeing usable space within, and on the surface of the mobile station.

DETAILED DESCRIPTION OF THE INVENTION

Those skilled in the art, after reading the specification, will understand that the principles of the present invention may be implemented in a variety of similar electronic device applications, in addition to the devices specifically discussed herein. That is, while the illustrated embodiment of the present invention depicts a folding design for a mobile station, such as a mobile phone, it is equally suitable for other similar devices such as lap-top computers, personal digital assistants (PDAs), and the like. As mentioned above, for convenience such devices and those like them will herein be referred to generically as “mobile stations.”

As described in detail above, conventional mobile stations of the type illustrated inFIG. 1typically employ a cylindrical hinge that provides a somewhat awkward mechanical appearance. This appearance generally persists regardless of the mobile station manufacturer or specific application (e.g., mobile phone, PDA, lap top computer, etc.). The present invention provides a functionally, structurally and aesthetically improved folding mobile station. Further, it provides a manufacturer with greater design freedom by accommodating a continuous surface between its two halves when the mobile station is placed in an open position.

The present invention also significantly limits manufacturing costs. Specifically, the present invention reduces the number and complexity of necessary parts and further reduces cost by simplifying the manufacturing process. As shown inFIG. 1C, conventional hinges require the precise insertion of a small hinge pin180through internal hinge components such as a tension spring182, static and dynamic detent assemblies184that bias the station in open and folded positions, and finally through an awkwardly wrapped electronic ribbon185that electronically connects the first110and second portions150of conventional mobile stations. The present invention advantageously eliminates this problematic “threading” of the hinge pin180while simultaneously streamlining the hinge design by eliminating many of the above internal hinge components including, the hinge pin180itself, the internal spring182, and the internal static and dynamic detent assemblies184. Further, the improved mobile station eliminates the awkward wrapping of the electronic ribbon185and allows for a simpler z-axis assembly of the hinge itself.

FIGS. 2A to 2Dare orthographic and perspective views showing a folded mobile station200built in accordance with one embodiment of the present invention. The mobile station200, shown folded, has two body units260,265that may be constructed, for example, of a rigid polymer shell so as to add structure and durability. The mobile station200also includes a tension unit230generally provided at the attachment point between body units260,265. The tension unit230provides a biasing force to the rigid body units260,265so as to maintain the mobile station200in open and folded positions. A flexible cover250is provided, as described in detail below, for providing a continuous visual transition from the inner surfaces of the two body units260,265. When folded, as shown, the elastomer material that comprises a preferred flexible cover250may provide a tactical gripping surface to aid when opening a folded mobile station200.

In one embodiment, the tension unit230may be attached to body units260,265via mounting structures220,221. As described below, the mounting structures220,221extend from the tension unit230into attaching slots located on the body units260,265. An attachment plate210covers the slots and prevents the mounting structures220,221from becoming detached. As will be apparent to one of ordinary skill in the art in view of the foregoing, the tension unit230, in conjunction with a folding hinge (not shown), pivotally connects the body units260,265and biases the units between open and folded positions. Additionally, the tension unit230may optionally provide a surface231displaying visual indicia such as a fixed advertisement, a stamped logo, or the like. In yet another embodiment, the tension unit230could provide a dynamic outer surface including a display231connected to operational elements within the mobile station200. In mobile phone applications, the display231may present important user information, such as a pending call or a number of queued messages. This information could be provided to users in any manner of audio/visual media (e.g., LED, LCD) that is commonly known in the art.

The body of the tension unit230may be comprised of various materials including, for example, plastic or other polymer materials, metals, and the like. For aesthetic or other purposes, the edges of the tension unit230may be tapered to fit flushly into one or more receiving surfaces255of body units260,265, as illustrated inFIG. 2D. A power interface270may optionally be provided to receive an external signal or battery charger cable, as illustrated inFIG. 2B. Grooves280may also be provided on the body units260,265in order to provide a non-slip or tactile gripping area to open the mobile station200.

FIG. 3is an exploded view showing several internal hinge components of a mobile station300in accordance with one embodiment of the present invention. The depicted mobile station300comprises a flexible cover250, a flexible circuit connector320, a folding hinge330, a first body unit260, a second body unit265, and a tension unit230. In the depicted embodiment, the first and second body units260,265include a plurality of relatively delicate operational elements (e.g., a display312, a keypad315, a speaker port313, a microphone port311, etc.) that are disposed on or integral to the flexible cover250. Accordingly, as the first and second body units260,265are disposed adjacent one another in the folded position (shown inFIGS. 2A–2D) the plurality of operational elements are protected from potentially damaging impact or contact with foreign substances. AlthoughFIGS. 3–4depict certain operational elements adjacent either the first or second body units260,265it is important to note that the present invention is not limited to the depicted configuration, and in fact, the various elements may be disposed adjacent either the first or body units260,265as known in the art.

Body units260and265may be referred to as the mobile station's engines or, alternatively, the mobile station's first and second functional units. In one embodiment a flexible circuit connector320connects the operational elements housed within the body units260,265in a manner known to those skilled in the art. In the depicted embodiment, the flexible cover250spans the body units260,265while concealing the flexible circuit connector320. In various embodiments, the flexible cover250protects the flexible circuit connector320from bending too sharply or kinking, by forming an internal radius around which the flexible circuit connector320is manipulated when the mobile station is folded. In one embodiment, the flexible cover250may be constructed of an elastomeric polymer to provide enhanced flexibility. In another embodiment, the flexible cover250may be constructed through3D printing techniques such as those proposed by Vivek Subramanian's work on flexonics at the University of California at Berkeley. Vivek Subramanian, (visited Jul. 28, 2003) <http://www-device.eecs.berkeley.edu/˜viveks/pubs.htm>. In either of the embodiments referenced above, the flexible cover250may be attached to the body units260,265by any means currently known, such as adhesive bonding, in-molding, metal or other rigid inserts, and the like.

In another embodiment of the present invention, a mobile station300may employ a flexible cover250that includes a plurality of ZEBRA® connector areas322constructed therewithin. As will be apparent to one of ordinary skill in the art, ZEBRA® connectors are flexible layered elastomeric connectors. Such ZEBRA® connector areas322could be used to prevent the flexible circuit connector320from having to carry the full electrical load of the mobile station300. In another preferred embodiment of the present invention, the ZEBRA® connectors322may replace the flexible circuit connector320entirely by carrying all electrical signals between the first and second body units260,265. Accordingly, the utility provided by the flexible circuit connector320and the flexible cover250could be combined into a single functional cover (not shown) other flexible cover250embodiments may include simpler, conventional electrical connectors as known in the art.

In alternate embodiments, the functional cover, as with the flexible cover250for that matter, could be designed with quick release electrical connectors (not shown) so as to be readily replaceable. Thus, a user having selected a particular style of mobile station could potentially change the look and feel of the mobile station by replacing the functional cover and/or flexible cover. In addition, the body units260,265too, could be manufactured so as to be replaceable. Again, by providing quick release fasteners (not shown) the polymer shells that generally comprise the body units260,265could be readily replaceable. Accordingly, users could purchase a number of such body units260,265for use in customizing the appearance and potential functionality of the mobile station.

Hinge assemblies in accordance with several embodiments of the present invention may comprise a folding hinge330mechanically attached to the first and second body units260,265as shown, or, alternatively, may include body units260,265having an integral folding hinge330(not shown). As referenced above, hinge assemblies according to various embodiments of the present invention rely on tension units230for biasing the first and second body units260,265between open and folded positions. Such units230significantly reduce manufacturing costs by eliminating several complex internal components and by streamlining the mobile station design. Additionally, tension units230accommodate a simplified z-axis assembly, wherein the mobile station components (e.g., the first and second body units260,265, the folding hinge330, the flexible connector320, and the flexible cover250) are advantageously built one atop the other in the z-axis direction. In contrast, when manufacturing the prior art hinges described above, an assembler must maneuver components along all axes, if such movement is possible given space considerations, in order to snake the flexible ribbon cable185through various channels formed by the internal hinge components. To make conventional assembly processes more difficult, the hinge pin180must be inserted through the spring-loaded internal biasing detents184, while the entire assembly is under tension.

To summarize, tension units230according to various embodiments of the present invention provide a vastly improved ergonomic design. The tension units230may be quickly and efficiently assembled by fixing the folding hinge330in place, adding the electrical circuit connector320, and then attaching mounting structures220,221to the first and second body units260,265. In this regard, the mounting structures220,221are generally attached to the first and second body units260,265by inserting distal portions of the mounting structures220,221into corresponding attaching slots that are covered by one or more attachment plates210. As referenced above, the one or more attachment plates210prevent detachment of the mounting structures220,221. In addition to its structural and biasing functions, the tension unit230may also provide a novel interface for accessories such as wearables, car holders, desk stands, etc. For example, in one embodiment, the tension unit230may include a clip, hook, tab or other similar device (not shown) for affixing portable mobile station to a user's belt or a docking station. With regard to the latter embodiment, the tension unit230may include one or more electrical connectors (not shown) for connecting to a power source, battery charger or other similar device provided within the docking station as known in the art. In addition to the functional properties above, the tension unit230also provides aesthetic benefit as it provides a uniquely continuous visual line when the product is folded.

FIGS. 4A,4B,4C and4D depict orthographic and perspective views of an “open” mobile station200constructed in accordance with preferred embodiments of the present invention. The flexible cover250includes a display312that may be integrated into the flexible cover250or may alternatively be mounted integral to the first body unit260. In the latter embodiment, the flexible cover250would simply provide a cutout or transparent cover that, when assembled, would be aligned with the integral display (not shown) that is attached or integral to the first unit260. In the former embodiment, the flexible cover250could be designed such that the cover material itself produces the display. For example, display portions such as those illustrated by reference numbers317,312, and315may be provided via active materials capable of flexible display such as those provided by E-Ink (Cambridge, Mass.) or OLED materials. Additionally, these areas may also provide touch input or haptic output with materials such as EMFiT®, which is available from Emfitech Ltd. of Vaajakoski, Finland. EMFiT® is an elastic, permanently charged electret film that converts mechanical stress into proportionate electrical energy, and conversely, mechanically expands when voltages of opposite polarities are applied.

As with the displays discussed above, the speaker port313and the microphone311may be embedded into the flexible cover250or alternatively, the cover could merely have openings to provide access to these components, which could be integrated within body units260,265. In mobile phone applications, such openings would additionally allow sound to travel to and from the microphone and speaker respectively.

In one embodiment, a portion of the flexible cover250may be designated as a fold area317, which is designed to encourage the foldable hinge330to flex properly at the desired point. The fold area317may be narrowed, necked down, or crimped at or near the axis or axes of rotation. Also shown is an interface area270for connecting the mobile station200to external devices such as, chargers, computers, hands-free kits, etc. The connection may be through conductive, optical transmission, inductive near field transmission or short range wireless transmissions such as Bluetooth, RFID, 802.11 and the like.

Turning toFIG. 5, a rear view of a mobile station built in accordance with embodiment of the invention is illustrated. The depicted mobile station200is placed in an open position to illustrate one preferred mounting orientation of one tension unit230embodiment. Specifically, the tension unit230attaches to the first and second body units260,265via mounting structures220,221. The mounting structures220,221may be fixed to the respective body units260,265by attachment plates210. In various embodiments, the tension unit230may include one or more apertures as shown. Such apertures may be provided to compliment the aesthetic appearance of the mobile station, to reduce the weight of the tension unit230, to provide external access to various internal parts (e.g., mounting structures220,221, connector ports, LED displays and the like), or to provide means for docking station attachment.

FIG. 6provides a detail view of the tension unit230embodiment depicted inFIG. 5. Specifically shown, is a tension unit230comprised of a body portion231and mounting structures220and221, which may have cylindrical cross section, may be pressed from flat stock, produced as a molded integral unit or otherwise manufactured as commonly known in the art. In one embodiment, for example, the mounting structures220,221are formed of a resilient metal, such as spring steel. Each mounting structure generally extends from a proximal end that is engaged by the body portion231of the tension unit230to a distal end that is engaged by the first and second body units260,265. Although the ends of each mounting structure may be engaged in various manners, the proximal ends of the mounting structures are disposed in a central cavity defined by the body portion231and secured therein by a cover650. The cover650, in turn, may be secured to the body portion231in any desired manner including by adhesive or by a snap-fit engagement. In order to reduce the size or profile of the tension unit230, the body portion231can define slots leading into the central cavity for receiving medial portions of the mounting structures220,221as shown.

As shown inFIG. 5, the distal ends of the mounting structures220,221may be disposed in corresponding attaching slots defined by the exterior of the first and second body units260,265. The attaching slots (and attached mounting structures) are covered with one or more attachment plates210such that the distal ends of the mounting structures220,221are secured within the attaching slots. As with the cover650referenced above, the attachment plates210may be secured to the first and second body units260,265in any desired manner including adhesive, snap-fit engagement or the like.

Although the mounting structures220,221are shown to be distinct, the proximal and/or the distal ends of mounting structure220may be joined by a connecting member (not shown), and the proximal and/or distal ends of mounting structure221may be joined by a connecting member (not shown). For example, the mounting structures may be C-shaped bands having distal ends configured to engage the first and second body units and a median region defined therebetween. The median region is coupled to the body of the tension unit and the distal ends of the mounting structures220,221may be attached to the first and second body units260,265in a variety of techniques known in the art, in addition to those referenced above.

The tension unit230may also generally include a spring or other tension device or mechanics within the central cavity. As described below, the spring or other tension device serves to connect mounting structure220and mounting structure230so as to facilitate opening and closing of the mobile station. In this regard,FIG. 7illustrates a compression spring in accordance with the one embodiment of the present invention. The springs provided are not intended to be limiting and other types of springs or tension devices may be employed. In the depicted example, a tension unit structure730comprises two mounting structures720,721. The mounting structures720and721are moveably coupled by a spring750that is disposed in the central cavity defined the body portion731of the tension unit structure. The spring750provides a resistant force F to the mounting structures720,721.

FIG. 8illustrates another embodiment of a tension unit830in accordance with the present invention. Specifically, a C-spring tension unit830is provided having a more robust and durable structure than the tension units according to various other embodiments. In one embodiment, this durability is provided, inter alia, by a C-spring850that is attached to a hinge820by two shafts840,845. The shafts840,845extend through channels841,846and also through similar channels or loops870formed in the hinge820and in the opposite side of the C-spring850. A slot865may be provided to accommodate a recessed placement of the C-spring850within the hinge assembly820as shown. The C-spring tension unit830may be mounted to first and second body units260,265by fasteners (not shown) through mounting holes860,861. There are similar mounting holes862on posterior side of the hinge821as shown.

FIG. 9provides a further detailed illustration of the hinge assembly depicted inFIG. 8. Notably, as will be apparent to one of ordinary skill in the art,FIG. 8depicts the hinge assembly in a folded position whileFIG. 9depicts the hinge assembly in an extreme open position.FIG. 9depicts two subassemblies. The first subassembly800generally consists of the C-spring tension unit830described above. According to the depicted embodiment, the C-spring850attaches to a folding hinge820via shafts840and845. In this regard, the shafts extend through the channels841,846defined by the folding hinge820, as well as through corresponding channels or loops870extending lengthwise along opposite sides of the C-spring850. The second subassembly900generally consists of a back plate955attached to the C-spring850in accordance with yet another embodiment of the present invention. The back plate955may be attached to the C-spring850via various methods known in the art. One preferred method of attachment is shown, wherein tongued structures930provided on the back plate955are slipped onto a flat portion of spring850such that opposed edges of the spring are engaged by the corresponding tongued structures930. A surface931for placement of a logo or other display may be provided on a display plate935that attaches or is otherwise adhered to, or is perhaps integral to back plate955. In other embodiments, the backplate and display plate may be provided as an integral structure (not shown) as know in the art

FIG. 10is a section view of a mobile station hinge in accordance with one embodiment of the present invention. As referenced above, the folding hinge820defines channels841,846for receiving shafts (shown inFIG. 9) that attach the hinge to the spring850or other tension unit embodiment (not shown). In one embodiment, the folding hinge820is a relatively V-shaped hinge as shown, thus, defining a distinct pivot axis825inwardly adjacent the inner surfaces of the first and second body units260,265of the mobile station as shown. For the purposes of the present specification and appended claims the term “inwardly adjacent” refers to position offset from the intersection of the inner surfaces of the first and second body units260,265of the mobile station in a direction extending generally toward the tension unit850. As will be apparent to one of ordinary skill in the art, the depicted configuration is preferable to conventional barrel or piano-type hinge assemblies that necessarily form a semi-cylindrical ridge along dashed line R and, thus, necessarily reduce the amount of usable space provided on the interior of the mobile station. The elimination of such semi-cylindrical ridges R also accommodates a relatively planar and continuous flexible cover (shown as250inFIG. 3). As referenced above, in various embodiments of the present invention, such covers may be printed in the folded area (317inFIG. 4C) to include visual indicia such as logos, printed electrical circuits, and the like, whereas under conventional hinge designs such printing would not have been possible.

FIGS. 11A,11B, and11C illustrate the relative orientation of the back plate955of the hinge assembly when the mobile station is placed in various positions. A simplified representation of the relative movement of the spring850, the shafts840,845, the body units260,265and the pivot axis825are further provided.

FIG. 11Aillustrates the relative orientation of the back plate955of a preferred hinge assembly when the improved mobile station is placed in a folded position.FIG. 11Billustrates the relative orientation of the back plate955when the mobile station is placed in a midway open position.FIG. 11Cillustrates the relative orientation of the back plate955when the mobile station is in the open position. The precise functionality of the improved hinge assembly will become apparent to one of ordinary skill in the art after reviewingFIGS. 11A,11B, and11C. Of particular note, is the relationship between the pivot axis825and the line HL extending through spring pivot points890,895. The placement of spring pivot points890,895generally coincides with the position of the center axis of shafts840,845. InFIG. 11Afor example, the mobile station pivot axis825resides substantially above spring pivot points890and895. As the mobile station transitions to the midway open position as illustrated inFIG. 11B, the pivot axis825is more closely aligned horizontally with the spring pivot points890,895. Finally, in the open position illustrated inFIG. 11C, the pivot axis825, resides substantially below the spring pivot points890,895. Accordingly, as the improved mobile station of the present invention is opened, the pivot axis825falls from above, to substantially below the relative position of spring pivot points890,895. As the mobile station closes, the reverse process occurs, wherein the pivot axis825returns to a final folded position substantially above the spring pivot points890,895.

FIGS. 12A and 12Bprovide a geometrical representation of the movements described inFIGS. 11A,11B and11C. InFIGS. 12A and 12B, the spring pivot points890,895are designated as spring pivot points P1, P2. The length L describes the distance between the respective spring pivot points P1, P2and the back plate955attachment points B1, B2. As the mobile station is opened and folded, the spring pivot points P1, P2are directed along arcs1245,1240. The top points T1, T2or apex of the spring pivot points' P1, P2rotation (i.e., arcs1245,1240) about the pivot axis825may be derived by extending a vertical line (90 degrees from horizontal line “CL”) from hinge pivot axis825until the line intersects arcs1245,1240. The points indicated by these intersections represent the apex of the respective arcs and are thereby designated as top points T1, T2. When the spring pivot points P1, P2are below top points T1, T2and to the right of pivot axis825as shown inFIG. 12A, the tension unit230holds or biases the body units260,265together (i.e. in a folded position). In other words, force is required to advance body units260,265past the top points T1, T2into an open position. This force is stored in the spring as potential energy. Upon passing the midway point of the fold (top points T1, T2), the stored potential energy forces the body units260,265into an open position. In short, the tension unit230according to various embodiments of the present invention biases the mobile station in both an open and folded positions, depending upon its position relative to the pivot axis825. In addition, by providing a C-shaped spring, C-shaped bank, compression spring/mounting structure assembly or other similar devices that resists the vertical displacement of pivot points P1, P2, various embodiments of the present invention are maintained in either their open or folded positions.

To ensure the mobile station is biased evenly as described above, and in order to fix the ultimate placement of the improved tension unit230, angle bisecting lines1350,1360and meridian lines1380,1390may be constructed during the as shown inFIGS. 13A through 13F. For the purposes of the foregoing analysis, the first and second body units260,265are symmetrical. Each body unit260,265includes an inner surface5,6an outer surface10,11and an end surface15,16. Angle bisecting lines1350,1360represent a series of positions wherein the spring may be attached to the body units,260,265such that an equal biasing force may be maintained toward both the open and folded positions. By placing the spring pivot points P1, P2on angle bisection lines1360and1350, the spring has substantially the same shape (and therefore applies substantially the same force) when open and folded. To construct angle bisecting lines1350,1360one merely provides a line bisecting angle β defined between the inner surface5and the end surface15of a given body unit260as shown. Pivot points P1, P2placed along these lines travel in a uniform arcs as shown inFIGS. 13A–13E; thereby resulting in an equal vertical displacement Y, Y′ in both the open and folded positions as shown inFIGS. 13A and 13Erespectively. Thus, as known in the art, springs and other similar devices as described above apply an equal opening and folding force to the mobile station.

Meridian lines1380,1390are constructed to control the location of the back plate1355relative to the pivot axis1325specifically, and the mobile station generally. The back plate1355will be equidistant from the pivot axis1325in both the open and folded positions if the spring pivot points P1, P2are placed along the meridian lines1380,1390. Accordingly, the precise contour of the back plate1355may be designed to provide optimal fit in relation to the ends of the first and second body units of the mobile station as described below.

Meridian lines may be constructed by at least two methods.FIGS. 13A–13Edepict meridian lines1380,1390constructed by a first method, andFIGS. 14A–14Cdepict meridian lines1413constructed by a second method. The first method simply requires extending a perpendicular line1380,1390from the end surface15of a given body unit260. In the depicted embodiment, spring pivot points P1, P2are placed at the intersection of angle bisecting lines1350,1360and the meridian lines1380,1390. Accordingly, the depicted mobile station requires an equal opening and closing force and also includes a back plate1355that is equidistant from the pivot axis1325in both the open and folded positions.

FIGS. 14A through 14Cillustrates a second method for constructing meridian lines1380,1390according to yet another embodiment of the present invention. This second method is particularly advantageous when a gap G is provided between the back plate1355and the mobile station as shown. The second method involves designating a first reference point R on the back plate1355proximate to its center. The relative position of the first reference point R remains constant when the mobile station is placed in the open and folded positions. A distance d is determined between the first reference point R and the pivot axis1325. An arm is extended from pivot axis1325along the line formed by end surface16. The arm extends beyond outer surface11a distance d to define second reference point RP. Reference line1412is then drawn to connect the first reference point R and the second reference point RP. At the midpoint of line1412a perpendicular line is extended as shown inFIG. 14B, thereby forming a meridian line1413. In one embodiment, angle bisecting line1450may be provided as described above to set spring pivot point P2as shown. The above process is repeated for body unit265so as to produce a second meridian line and set spring pivot point P1for symmetrical body unit265.

As referenced above, in one embodiment, the pivot points P1and P2are set at the respective intersection of angle bisecting lines and meridian lines. As a result, the forces required to open and close the mobile station are substantially equal and the position of the back plate is substantially equidistant from the pivot axis in both the open and folded positions. In alternate embodiments, however, mobile station designers may wish to alter the above characteristics for various design considerations. For example, returning toFIG. 13A, one embodiment may be configured such that the pivot points P1, P2are set along meridian lines1380,1390and off angle bisecting lines1350,1360. In particular, the pivot points P1, P2could be moved axially rearward (toward the back plate1355) to produce a mobile station having a required opening force that is less than its required closing force. Alternatively, the pivot points P1, P2could be moved axially forward (away from the back plate1355) to produce a mobile station having a required opening force that is greater than its required closing force. In other embodiments, the pivot points P1, P2may remain along angle bisecting lines1350,1360and instead be positioned off meridian lines1380,1390. In particular, the pivot points P1, P2could be moved rearward along the angle bisecting lines (toward the pivot axis1325) to produce a smaller gap G between tension unit and an opened mobile station. Alternatively, the pivot points P1, P2could be moved axially forward (away from the back plate1355) to produce a mobile station having a larger gap G between the tension unit and an opened mobile station. The above relationships between pivot point location and the angle bisecting and meridian lines may be used alone or in combination to produce multiple additional desirable embodiments as will be apparent to one of ordinary skill in the art.

FIGS. 15A and 15Dillustrate the relative interaction between the back plate and the mobile station in accordance with various preferred embodiments of the present invention. As will be apparent to one of ordinary skill in the art, several configurations are possible for body units260,265in order to accommodate an efficient fit with back plate1555. The precise contour of the back plate1555may be dictated by the desired gap G provided between the back plate1555and the pivot axis1525. For example, if a relatively small gap G is preferred the back plate1555should include a relatively broad radius at its interior ends as depicted inFIGS. 15B and 15C. Alternatively, if a relatively large gap G is desired, the back plate1555may include interior ends having a tighter or relatively smaller or radius as shown inFIGS. 15A and 15D. In various embodiments, the back plate1555may include a “squared” corner1510having little or no radius as shown inFIG. 15A. In another embodiment, the back plate1555may include interior corners1520having a relatively larger radius as illustrated inFIG. 15B. In another embodiment, the back plate1555may include “inverted squared” interior corners1530having squared cutouts as illustrated inFIG. 15C. In yet another embodiment, the back plate1355may include a relatively small radius defined by its interior corners as illustrated inFIG. 15D. Alternate filleted or chamfered cornered embodiments may also be provided as known to one of ordinary skill in the art.

It should be pointed out that these are illustrated embodiments only, and that the repeated presence or absence of a particular feature does not imply that it is a required component of the invention absent on explicit statement to that effect.