Apparatus for opening hand held electronic device

A hinge is constructed for automatically opening the cover panel of an electronic device. The hinge assembly includes a torsion bar on which is concentrically mounted a series of cylindrical barrels. The torsion bar is fixed to the base of the device at one end and to the cover at its other end in such a manner that the torsion acts as spring which is loaded by the closing rotation of the cover. The cover is opened by releasing the loaded torsion bar and allowing the cover to rotate to its open position. Viscous damping is provided to control the rotation of the cover support barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT The panel opening hinge 30 of this invention is described below with reference to a personal information manager having a base panel 1 in which is mounted a keyboard 3 and a cover panel 2 in which is mounted a display 4 , but it should be noted that the system is equally adaptable to other types of electronic devices such as, computers, pagers, game controllers and the like. The components of the hinge mechanism 30 of this invention are shown in disassembled relation in FIG. 1 . For convenience of illustration the hinge assembly 30 is enlarged with respect to the panels. Panels 1 and 2 are connected by the hinge mechanism through aligned bores 22 and 23 to allow movement of the cover panel 2 relative to the base panel 1 in the direction of arrow 21 about the axis x-x. The cover panel 2 is allowed to move between a closed position at which it covers keyboard 3 and an open position at which the display 4 is visible and keyboard 4 is easily accessed. The total relative movement between the panels 1 and 2 is through an obtuse angle of about 135°. The movement of the cover 2 is provided through torsion bar 5 which is fixed at end 24 to the base panel 1 and at its other end 25 to cover panel 2 through damping barrel 6 , cover support barrel 7 , and cover coupling barrel 8 , as described below. The torsion bar 5 will act as a spring which is charged by the closing movement of the cover panel 2 and releases when actuated by the user. End 25 of the torsion bar 5 is free to rotate (within a 135° range, while end 24 is fixed. This forces the bar 5 to twist during the closing motion of cover 2 . Torsion bar 5 is constructed of an appropriate material that has a torsional elasticity which will return the bar 5 to its untwisted position. In the preferred embodiment torsion bar 5 is constructed of superelastic nickel/titanium alloy wire, such as is sold under the trademark NITINOL by Nitinol Devices & Components of Fremont, Calif. The superelasticity of this material combines to provide a spring of extremely compact form which has sufficient spring torque to open the display panel 2 and a suitable durability. A torsion bar having a diameter of 0.84 mm and a length of 50 mm has been used with good results. The torsion bar 5 forms the axially aligned base of the hinge assembly 30 . The other parts of hinge 30 are cylindrical barrels which are assembled concentrically around the torsion bar 5 . As shown by assembly bracket 26 , base 1 is mounted on torsion bar 5 through damping barrel 6 and is fixed to end 24 of torsion bar 5 through a base coupling barrel 9 . Base coupling barrel 9 contains the release mechanism 31 . Assembly reference bracket 27 is used to indicate that a cover support barrel 7 is also mounted on torsion bar 5 , but over damping barrel 6 . Cover support barrel 7 is fixed to end 25 of the torsion bar 5 and supports the cover panel 2 . A cover coupling barrel 8 is fixed to one end of the cover support barrel 7 and engages the release mechanism 31 to hold the cover in the closed position. Damping barrel 6 is constructed with a pair of O-rings 11 and 12 mounted on its periphery. O-rings 11 and 12 form a damping chamber 10 in cooperation with the interior surface of bore 29 of cover support barrel 7 . An appropriate grease can be confined within the chamber 10 to function as a viscous damping fluid. The friction between the cover support barrel 7 and damping barrel 6 during relative rotation of these members, creates a damping torque which controls the movement of the panel 2 under the influence of torsion bar 5 . In one embodiment of the invention, as shown in FIG. 2 , the release mechanism 31 of the hinge assembly consists of a ball detent 16 mounted on a peripheral surface of base coupling barrel 9 . Ball detent 16 is biased in the protruding position, as shown in FIG. 2 , by a wedge shaped member 13 . A spring 17 is positioned to exert a force on the wedge 13 in the direction shown by arrow 19 . An actuating mechanism is connected through flange 14 of wedge member 13 to exert a release force in the direction shown by arrow 18 against spring 17 . Preferably the actuation is accomplished by a button mounted on the axis of the hinge 31 and causing a force 18 to be exerted through an appropriate linkage. In a preferred embodiment, a shape memory wire is used, (also available from NDC of Fremont, Calif.) to actuate the spring detent release mechanism 31 . To accomplish this a memory_wire 34 is connected to flange 14 as shown by a phantom line, in FIG. 2 . The memory shape wire will contract under the influence of heat and move the wedge 13 against spring 17 . Heat is provided by connecting the memory wire to a source of current such as a battery (not shown). The release mechanism of this embodiment will be actuated by pressing a button (not shown) to energize the memory wire. This allows the release button to be positioned in a more convenient position. Cover coupling barrel 8 is constructed with a cylindrical opening 15 which will engage ball detent 16 to lock the cover 2 is in the closed position. Cover coupling barrel 8 is mounted on cover support barrel 7 and may be allowed to rotate through a sector of 450 relative to barrel 7 . This allows movement of the cover relative to the base to allow adjustment of the position of the cover beyond the 135° angle otherwise provided. This extra movement is needed to accommodate accidentally forced extension or more customized positioning of the display. To hold the cover in place, the torsion bar 5 is not totally released at the 135° angle. A residual spring torque is maintained amounting to approximately a 30° rotation. Closing the cover recharges the spring torque to its opening energy. A pair of O-rings 32 and 33 may be mounted on the outer surface of barrel 7 to provide a friction damping torque for the relative motion of coupling barrel 8 on cover support barrel 7 . In operation of the hinge of FIG. 1 , the torsion spring 5 is twisted by the closing motion of cover 2 . This generates a torque which is restrained by release mechanism 31 , as ball detent 16 of base coupling barrel 9 engages opening 15 of cover coupling barrel 8 . By retracting wedge element 13 from engagement with ball detent 16 , the stored torque of torsion bar is released. Since cover support barrel 7 is free to rotate on damping barrel 6 and is fixed to the free end 25 of torsion bar 5 , cover 2 will automatically open under the influence of viscous damping provided by the damping chamber 10 . An alternate embodiment of the invention is shown in FIGS. 3 and 4 . In this embodiment a hinge assembly 50 is shown which is simplified by removing the release mechanism from the hinge assembly. The components of the hinge mechanism are shown in disassembled relation in FIG. 3 . For convenience of illustration the hinge assembly 50 is enlarged with respect to the panels. Panels 1 and 2 are connected by the hinge mechanism 50 through aligned bores 52 and 53 to allow movement of the cover panel 2 relative to the base panel 1 in the direction of arrow 51 about the axis x-x. The cover panel 2 is allowed to move between a closed position at which it covers keyboard 3 and an open position at which the display 4 is visible and keyboard 4 is easily accessed. The total relative movement between the panels 1 and 2 is through an obtuse angle of about 135°. The movement of the cover 2 is provided through torsion bar 5 which is fixed at end 54 to cover panel 2 through damping barrel 6 , and friction coupling barrel 59 , as described below. End 55 of torsion bar 5 is connected to the base 1 through end 71 of support barrel 57 . Opposite end 58 of support barrel 57 is fixed to base 1 . The torsion bar 5 will act as a spring which is charged by the closing movement of the cover panel 2 and releases when actuated by the user. End 54 of the torsion bar 5 is free to rotate, while end 55 is relatively fixed. This forces the bar 5 to twist during the closing motion of cover 2 . Torsion bar 5 is constructed of an appropriate superelastic material as described above. The torsion bar 5 forms the axially aligned base of the hinge assembly 50 . The other parts of hinge 50 are cylindrical barrels which are assembled concentrically around the torsion bar 5 . As shown by assembly bracket 66 , base 1 supports torsion bar 5 through support barrel 57 and is fixed to end 55 of torsion bar 5 . Assembly reference bracket 67 is used to indicate that damping barrel 56 is also mounted on torsion bar 5 , through internal bore 72 of support barrel 57 . As shown in FIG. 3 , damping barrel 56 is connected through friction coupling barrel 59 to the cover 2 . Key 78 engages the damping barrel 56 to allow limited relative rotation between the damping barrel 56 and torsion bar 5 in the amount of 135°, as shown by arrow 35 . As in the embodiment of FIG. 1 , damping barrel 56 is constructed with a pair of O-rings 61 and 62 mounted on its periphery. O-rings 61 and 62 form a damping chamber 60 in cooperation with the interior surface of bore 72 of support barrel 57 . An appropriate grease can be confined within the chamber 60 to function as a viscous damping fluid. The friction between the support barrel 57 and damping barrel 56 during relative rotation of these members, creates a damping force which controls the movement of the panel 2 under the influence of torsion bar 5 . As shown in FIG. 4 , friction coupling barrel 59 is mounted for limited rotation on damping barrel 56 . Coupling 59 is constructed of a series of cylindrical elements which include friction ring 74 , body 75 , and coupling ring 76 . Body 75 is mounted on end 77 of damping barrel 56 through friction ring 74 . Coupling ring 76 engages body 75 to allow limited rotation between damping barrel 56 and coupling barrel 59 in the amount of approximately 45°. This provides a safety measure for accidental extension of the cover or for customized adjustment. The friction between coupling barrel 59 and damping barrel 56 may be adjusted by the operation of screw 73 which engages a threaded hole in split end 77 of damping barrel 56 . By rotation of the screw the split end 77 may be selectively enlarged or reduced to provide more or less coupling friction as desired, through engagement with friction ring 74 . The operation of the embodiment of FIG. 3 is similar to hinge assembly 30 described above. Torsion spring 5 is twisted by the closing motion of cover 2 . This generates a torque which is restrained by an appropriate release mechanism which, when actuated releases the stored energy of the torsion bar and opens the cover. Since damping support barrel 56 is free to rotate up to 135° on torsion bar 5 , cover 2 will open under the influence of viscous damping provided by the damping chamber 60 . In the embodiment of FIG. 3, a hook or clasp type mechanism can be employed to hold the cover 2 in the restrained, closed position, while allowing release through one handed operation. FIG. 5 shows a mechanism 80 for connecting the display 2 to the main printed circuit board of the device. The configuration of the hinge assemblies of this invention, because of the small diameter hinge, facilitate the use of a flexible coiled plastic member 81 in which is imbedded wires (not shown) connected to display 2 . The connection flap 82 contains the terminal ends of the wires which are inserted in base 2 for connection to the main printed circuit board. The mechanism 80 is coiled internally within the bore of the electronic device which also accommodates hinge mechanisms 30 or 50 .