Latch mechanism

A latch mechanism (1200) comprises a resilient wire (404) supported proximate its first end (412) and second end (414) by a support structure (406). The latch mechanism (1200) also includes one or more hook shaped catches (218) that have cammed outer surfaces (302) and wire engaging openings (304). To engage the latch mechanism (1200) the resilient wire (404) is urged against the cammed outer surfaces (302) bending the resilient wire (404) and allowing the resilient wire to rebound into the wire engaging openings (304). To disengage the latch mechanism the resilient wire (404) is deflected, e.g., by pushing a moveable manual actuator (408) that is engaged with the wire, in order to release the resilient wire (404) from the wire engaging openings (304) of the catches (218).

FIELD OF THE INVENTION

The present invention relates in general to latch mechanisms. More particularly, the present invention relates to space efficient latch mechanisms for small portable electronic devices.

BACKGROUND OF THE INVENTION

There is an interest in making certain portable devices such as cellular telephones smaller. Making such devices smaller makes it more convenient to carry them around at all times.

Concurrently there is a trend toward increasing the functionality of devices. In the case of cellular telephones, increased functionality includes providing operability on multiple frequency bands using multiple protocols, and providing the ability to take photographs and/or video clips. Adding more functionality often leads to increased space requirements, which is at odds with the desire to make the devices smaller. Furthermore, depending upon the desired overall dimensions of the device, some of the dimensions for some of the components may be more critical than other dimensions. Thus, the amount of space, i.e. volume, available for accommodating components is at premium. Still further, the desire to accommodate more critical dimensions for one or more of the components is also a factor to be considered.

One component found in portable electronic devices such as cellular telephones, is a latch used to secure battery compartment covers. It is desirable to have a latch mechanism that takes up less space, relative to at least one or more dimensions.

DETAILED DESCRIPTION

The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

FIG. 1is a perspective view of a handheld wireless communication device in particular a cellular telephone100that includes a latch mechanism1200(not visible inFIG. 1) according to an embodiment of the invention. The assembled latch mechanism1200is shown inFIG. 12. Portions of the latch mechanism1200are shown inFIGS. 2-11. Although the latch mechanism1200described below with reference toFIGS. 2-12is incorporated in the cellular telephone100according to an embodiment of the invention, alternatively the latch mechanism1200and variations thereof are applied to a variety of different applications such as, for example, securing battery covers, or connector access covers for other portable electronic devices (e.g., handheld game consoles, MP3 players, handheld GPS receivers, cameras, or camcorders).

The exemplary cellular telephone100illustrated inFIG. 1has a two part housing, which includes an upper part102, and a lower part104. The upper part102and the lower part104are rotatably coupled together via a hinge106. While the exemplary embodiment illustrates a latch for use with a battery cover relative to a form of a two part housing phone also known as a clam shell style cellular telephone, one skilled in the art will readily appreciate, as previously noted, that the latch could alternatively be used in other types of devices, including devices incorporating other types of housings, such as one part housings, other types of two part housings, as well as housings having more than two parts.

FIG. 2is a partial exploded view of the cellular telephone100shown inFIG. 1, showing a battery compartment202, and a battery compartment cover204that is secured by the latch mechanism1200(FIG. 12). The battery compartment202is located in a backside206of the lower part104of the cellular telephone100. (The backside206is not visible inFIG. 1). A tab208that is attached to a lower end210of the cover204aids in securing the cover204. The tab208fits into a congruently shaped recess212that is located within the battery compartment202, and extends under an outer housing wall214of the lower part of104near a bottom end216of the battery compartment202.

A pair of hook shaped catches218is located near a top end220of the battery compartment202. A pair of triangular protrusions219, each of which are shaped to conform to a top end224of the battery compartment cover204, extend outward from positions at the top end220of the battery compartment202between the catches218. The triangular protrusions219help to locate the battery compartment cover204. A clasp222of the latch mechanism1200(FIG. 12) is attached to an inside surface223of the battery compartment cover204adjacent the top end224of the battery compartment cover204. The clasp222is suitably attached by adhesive. Alternatively, the clasp204and the cover are integrally molded.

In order to fit the battery compartment cover204to the battery compartment202, the tab208is first placed in the recess212so that it extends under the outer housing wall214. The top end224of the battery compartment cover204is then pushed toward the cellular telephone100so that the clasp222will engage with the hook shaped catches218. The structure of the catches218and the clasp222is described in more detail hereinbelow. Alternatively the lower end210of the cover204could be hinged to the lower part104of the cellular telephone100.

FIG. 3is a magnified view of one of the hooked shaped catches218of the latch mechanism1200(FIG. 12) according to an embodiment of the invention. As shown inFIG. 3the catches218each comprise an outer cammed surface302, and a wire engaging opening304. The function of the cammed surface302is similarly described in more detail hereinbelow.

FIG. 4is an exploded view of the battery compartment cover shown inFIG. 2, including the clasp222of the latch mechanism1200. As shown inFIG. 4, the clasp222comprises a resilient wire404, a support structure406, and a moveable manual actuator408. Inserting the resilient wire404into the support structure406and through an axial bore409in the moveable manual actuator408assembles the clasp222. The resilient wire404comprises first end412a second end414and a middle portion416with which the moveable manual actuator408engages. The clasp222is described in more detail hereinbelow.

FIGS. 5-10are several views of the clasp222. In particular,FIG. 5is a top view of the clasp222without the actuator408,FIG. 6is an exploded front view of the clasp222,FIG. 7is a partially cross-sectioned bottom view of the clasp222,FIG. 8is an exploded bottom view of the clasp222without the actuator408andFIG. 9is a back view of the clasp222without the actuator408. Note that the clasp222is attached to the cover204such that a back end902of the support structure406shown inFIG. 9faces the top end224of the cover204, and a bottom end701of the support structure406shown inFIG. 7is positioned on the inside surface223of the cover204.

Referring toFIGS. 5–9, support structure406comprises a middle section502, a first end section504, and a second end section506. A first longitudinally extending channel702is formed in the first end section504, and a second longitudinally extending channel704is formed in the second end section506. An axis of movement of a middle portion416of resilient wire404is marked with reference numeral508. In at least some embodiments, a force which produces the movement of the middle portion416of the resilient wire404is applied to the manual actuator408. One skilled in the art will also appreciate that the axis of movement can also be produced by a force applied directly to the resilient wire. In the perspective ofFIGS. 5,7,8the axis of movement508is vertical and in the perspective ofFIGS. 6,9the axis of movement508is perpendicular to the plane of the drawing sheet.

The cross-sectional dimensions of the channels702,704, measured parallel to the axis of movement508of the actuator408, taper from a smaller size that is only slightly larger than a cross-sectional dimension of the resilient wire404(measured parallel to the axis of movement of the actuator508) near a first end510, and a second end512of the support structure406to a large size that is significantly larger than (e.g. two-times) the cross-sectional dimension of the resilient wire404proximate the middle section502of the support structure406. The channels702,704are rectangular in cross-section along most of their lengths, and are open at the bottom end701of the clasp502as shown inFIGS. 7-8, however, ends of the channels702,704located at the ends510,512of the support structure406are formed into circular cross-section bores410. The bores410help to accurately locate the resilient wire404. Tapering, the channels702,704allows the resilient wire404to flex in order to engage and disengage from the catches218. Note that the middle portion416of the resilient wire404is suspended, and within limits is not constrained except by its own resiliency.

A first slot514extends perpendicularly from the front (FIG. 6) of the first end section504of the support structure406into the first channel702. Similarly, a second slot516extends perpendicularly from the front (FIG. 6) of the second end section506of the support structure406into the second channel704. When the cover204is placed on the battery compartment202, the catches218engage the resilient wire404through the first514and second516slots.

Angled surfaces518at the junction of the end sections504,506and the middle section502match the shape of the triangular protrusions219and aid in locating the cover204on the battery compartment202.

The middle section502includes a centrally located groove520that extends from the back end902of the support structure406perpendicularly with respect to the resilient wire404. A protrusion602extending from the actuator408locates in the groove520. The protrusion602and the groove520serve to constrain the motion of the actuator408to be perpendicular to resilient wire404, at the location of the actuator408. (Note that the maximum deflection of the resilient wire404is very slight in the embodiment shown in the FIG., e.g. equal to one or two diameters of the wire404.)

A fingernail hold604is provided in an actuation surface606of the moveable manual actuator408. The fingernail hold604is used to apply a force to separate the cover204, from the lower part104of the cellular telephone100.

FIG. 10is a fragmentary inside view of the battery compartment cover204shown inFIG. 2showing the clasp222in a first state. The clasp222is in the state shown inFIG. 10when the cover204is in place on the compartment202, and the catches218are located in the slots514,516and engaged with the resilient wire404. The clasp is also in the state shown inFIG. 10, when the cover204is removed from the battery compartment202, and any deflection force, which may have been applied to the moveable manual actuator to deflect the wire and release the door has been removed. As shown inFIG. 10, the resilient wire404is not under any stress, and is straight.

FIG. 11is a fragmentary inside view of the battery compartment cover shown inFIG. 2showing the clasp222in a second state. The second state shown inFIG. 11occurs during the processes of engaging and disengaging the clasp222. In disengaging the clasp222, a first force labeled1102is applied (e.g., with a fingernail) to the moveable manual actuator408, perpendicular to the actuation surface606, causing the resilient wire404to bow downward. As the resilient wire404bows downward, portions of the resilient wire404that are located in the slots514,516in the support structure406move downward clear of the catches218. Using the fingernail hold604a second force (directed into the plane of the drawing sheet, in the perspective ofFIGS. 10–11) is then applied to separate the cover204from the compartment202. One skilled in the art will readily appreciate that the second force could alternatively be applied by a preloaded spring like structure, which biases the cover204away from the compartment202, when the resilient wire404clears the catches218.

The state shown inFIG. 10can similarly occur, when the wire404and the corresponding one or more catches418of the clasp222are engaged. When the clasp222is being engaged, after the tab208has been placed in the recess212and a force is applied to bring the cover204into place (e.g. by pushing the cover204against the part104of the cellular telephone100) the angle of the outer cammed surfaces302of the hook shaped catches218will force the resilient wire404into the bowed state shown inFIG. 11. Continued pushing of the cover204will cause the resilient wire404to pass completely over the cammed surfaces302and rebound into the wire engaging openings304of the catches218.

FIG. 12is a cut-away view of the lower part104of the cellular telephone100shown inFIG. 1showing the battery compartment cover204latched over the battery compartment202. The battery compartment cover204is partially cut-away to reveal the structure of the latch mechanism1200including the clasp222, and the catches218, and their interrelation when latched together. As shown inFIG. 12, the catches218are located in the slots514,516and are engaged with the resilient wire404.

The above described latch mechanism is very compact in cross-sectional dimensions, and is well adapted for incorporation in the edge of a cover or door in a space efficient manner.

While the preferred and other embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those of ordinary skill in the art without departing from the spirit and scope of the present invention as defined by the following claims.