GB2426139A

GB2426139A - Spring/cam-driven mechanical opening mechanism for a sliding radiotelephone

Info

Publication number: GB2426139A
Application number: GB0509736A
Authority: GB
Inventors: Andrew Roberts; Colin Marshall
Original assignee: Sendo International Ltd; Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2005-05-13
Filing date: 2005-05-13
Publication date: 2006-11-15
Anticipated expiration: 2025-05-13
Also published as: GB0509736D0; GB2426139B

Abstract

A mechanism for generating a semi-automatic opening action, the mechanism comprising at least a first and a second module operably connected via a further sliding mechanism, and one mechanical energy storage device. The mechanical energy storage device or spring 815 is mechanically located 805 to only a first module (130, fig 1) via guide-pins 805. A second module (120, fig 1) is provided with a cam 900 and is mechanically located via a sliding mechanism to the first module (130). The guide pins 805 rest on the profile of the cam 900. The force/displacement function of the mechanism is determined by the cam profile 900 and characteristics of the energy storage device.

Description

WIRELESS COMMUNICATION DEVICE AND MECHANICAL ACTUATOR

MECHANISM THEREFOR

Field of the Invention

The present invention relates to a mechanism for providing mechanical assistance to a user during the opening or closing of an extendable device, such as that found in a slider-mobile telephone. The invention is applicable to, but not limited to, improving the usability of a wireless communication device, such as a mobile phone.

Background of the Invention

Portable devices, such as wireless communication devices, are required to become ever more compact, with ever increasing functionality. This places great demands on the device packaging and design. It is usual for a mobile phone to be constructed of two or more parts, each or all of which are incorporated into, and mechanically coupled together to form a single housing. The individual parts are typically mechanically connected to each other, via a mechanism that allows relative motion between them. Thus, simply moving one or more parts of the device relative to the others can change the form- factor of the device.

A typical slider-type mobile phone device comprises of a bottom (or rear) module containing the main mobile phone elements, such as the main printed circuit board, alphanumeric keypad and battery pack. The mobile phone device also comprises, sitting above the bottom module, a top module, which typically contains the liquid crystal display (LCD) and the navigation part of the keypad. In the closed state the product is compact and the user is able to receive calls and make calls using the navigation keypad. If the user wants to dial out, or text, the top module can be slid forward in a slider-phone to reveal the alpha/numeric keypad. One specific type of opening action is referred to in the industry as semi- automatic' . For semi automatic opening the user pushes against a spring system storing energy in the spring, after some travel, where the spring force switches over and releases the stored energy. Thus the product opens without further user intervention under the sole action of the spring.

Mechanisms are currently available to perform semi- automatic opening of mobile phone top modules. Typically they are based on a so called "over-centre action", whereby a spring is mounted between the two mechanical parts, which are to move relative to one another. This kind of mechanism is shown in FIG's 2-4 whereby one end of a spring is fixed to the main housing 230, the other end being fixed to the sliding part 220. A fixed base plate is attached to the bottom module 210 and a moving top plate is attached to the top module 200.

The user pushes the top module 200 forward against a spring. The spring is mounted between the fixed base plate and the moving top plate at two pivot points 220, 230 where it is free to rotate. As the top plate 200 is pushed forward by the user, the spring is compressed and begins to rotate. The pivot point on the moving top plate is forced closer to the pivot point on the fixed base plate. When the pivot points are opposite each other, as shown by arrangement 300 in FIG 3 the spring makes a 90 degree angle with the direction of motion, is fully compressed, and there is no forward or backward force. This is the switch-over point.

If the top module is pushed beyond this point the energy stored in the compressed spring is released (as illustrated in FIG. 4), the spring is free to expand, and force the top module forward.

However, this known prior art has a number of

disadvantages.

In order to ensure that there is sufficient locking force, and that it is the same in the both the open and closed positions, the switch-over point must be close to the centre of the travel. Therefore there is a limited ability to change the force/travel characteristic for the end user.

With a fixed switch over position, flexibility is restricted solely to the characteristic of the spring and the friction of the rail system.

Furthermore, as the spring translates and rotates relative to both the base and top plates, it must obviously be positioned between these plates. This adds additional thickness to such a mechanism. Also it restricts the motion to a straight-line planar type motion.

Thus, a need exists for a mechanism for facilitating semi-automatic opening of a mechanical device that has a minimum physical volume, reduced height/thickness, and provides an easily definable force/ distance characteristic, while at the same time alleviating the problems associated with the prior-art.

Statement of Invention

In accordance with a first aspect of the present invention, there is provided a mechanism, as claimed in Claim 1.

Further aspects and advantageous features of the present invention are as described in the appended Claims.

A mechanism according to the teachings of the current invention is described for facilitating a semi-automatic opening action of two mechanically connected modules of a mechanical device. The mechanism comprises at least one mechanical energy storage device constrained within the mechanism such that, when acted upon by an external force stores energy. The stored energy is then released at a later time to facilitate the semi-automatic opening action. The energy storage device is mechanically located to only a first module, a second module provided with a cam, being subsequently mechanically located to the first module such that the motion of the energy storage device is determined by the cam profile.

Thus, and advantageously, the act of storing and releasing energy, and the rate of storage or release of that energy is only constrained by the profile of the cam and the spring constant of the energy storage device.

Notably, it is not constrained by the mechanical fixing points of the energy storage device to the module.

Furthermore, the semi-automatic opening mechanism may now be assembled by hand, or automatically, to the first module independent of the second module, thus allowing a far more flexible and easier manufacturing process.

The restriction of the motion of the mechanical energy storage device to a single plane, allows an advantageous and substantial reduction in the physical volume required for the mechanism. Furthermore, when the plane of motion of the mechanical energy storage device is the same as the plane of motion of the first and/or second modules, then both the volume of the mechanism and the thickness of the mechanism may be minimised. The form of the energy storage device may thus be selected such that it provides the required energy storage characteristics and also minimises, beneficially, the height of the mechanism.

In yet a further advantageous embodiment of the current invention, the mechanical energy storage device is located to the first module at one or both of its ends by guide pins. The guide pins are themselves located to, and constrained to move in, a track, said track being substantially at 9Q0 to the direction of motion of the first and/or second module.

Thus, the guide pin mechanism acts advantageously as both the means by which the storage device is mounted to the module, and the means by which a force, acting on the first or second modules, and causing a relative displacement between the modules, is re-directed to act upon the energy storage unit. Thus, the displacement of the energy storage device is linked to the relative displacement of the first and second modules by the profile of the cam.

Furthermore, the track in which the guide-pins are located can be a simple cut-out in the module, or can be simply part of the injection moulding. This further reduces the manufacturing costs, the weight and the volume of the mechanism.

In a further advantageous embodiment, each guide pin performs the function of a bearing, which, when the first and second modules are located together, rests against the cam profile and provides a low friction mechanical contact with the profile. Thus, the guide pin itself provides a low friction sliding or rolling contact with the cam profile, thereby minimising further the mechanical part-count and increasing both the simplicity and reliability of the mechanism.

Advantageously, a simple, low cost, sliding coupling is used to mechanically link the first and second modules.

This is made possible by the wide range of energy storage device characteristics, and force/displacement characteristics, achievable with the mechanism that is the subject of the present invention.

In a yet further advantageous embodiment of the present invention, the sliding coupling could comprise one or more roller-bearings or ballbearings. Thus, the force required to generate relative motion between the modules is greatly reduced. This, in turn, reduces the demands made upon the energy storage device.

In a further advantageous embodiment, further energy storage device or devices could be mounted between the first and second modules. These further energy storage device(s) are located substantially at 900 to the primary energy storage device and coincident with the direction of motion of the first or second module. The further energy storage device(s) is/are advantageously mechanically fixed at one end to the first module. At the other end, the further energy storage device(s) is/are mechanically fixed to the second module. This provides extra force during an opening or closing action of the device, which may be designed to overcome friction in the slider and the cam mechanisms.

Advantageously, the first or primary energy storage device is a torsion spring. This is a reliable, low- profile, low cost device which is the optimal choice for minimising the height or thickness of the semi-automatic opening mechanism. In a yet further advantageous embodiment of the present invention, the primary energy storage device is a helical spring, which is configured to sit within the cut-out provided for the guide pins and thus reduce the space requirement of the primary energy storage device within the cam profile.

In order to provide a holding or detent force at specific points of the travel of the two modules, the cam profile is advantageously provided with one or more recess(es) in which the guide pins sit. The extra force required to move the guide pins out of the recess(es) against the action of the primary mechanical energy storage device acts as a detent force and allows for stable operating points of the device.

The teachings of the current invention are advantageously embodied in a portable electronic device, preferably a wireless communication device utilising semi-automatic opening action. The device is preferably constructed of two or more mechanical modules, and incorporates a mechanism according to the teachings of the current invention.

In this manner, the aforementioned problems associated with implementing a mechanical, semi-automatic opening action between two modules are resolved. This has been achieved primarily by the provision of, and interaction of, a cam in a first module, and a guide-pin and mechanical energy storage mechanism in the second module.

Relative motion between the modules causes the cam profile to apply a force to a primary mechanical energy storage unit via guide-pins, thus converting relative motion between the modules into stored energy. The stored energy is subsequently released on another section of the cam profile, causing the opening action.

The teachings of the current invention are applicable to any mechanical system that includes a sliding mechanism that must open and close, and would benefit from a semi- automatic operation. This includes mobile communication devices, such as mobile phones, as well as FDA's or music players. The teachings of the present invention can also be used beneficially in other areas such as automotive, and for other mechanisms such as ashtrays, cup holders, and the like.

Brief Description of the Drawings

Exemplary embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 illustrates a wireless communication unit adapted in accordance with the preferred embodiment of the present invention; FIG.'s 2, 3, 4 illustrate known mechanism; FIG.'s 5, 6, 7 illustrate the operation of a semi- automatic opening mechanism, adapted in accordance with the preferred embodiment of the present invention; FIG.8 is a schematic of a mechanism in accordance with the preferred embodiment of the present invention; FIG. 's 9, 10, 11 illustrate an opening or closing sequence of a semi- automatic opening mechanism, in accordance with the preferred embodiment of the present invention; FIG. 12 illustrates a semi-automatic opening mechanism in accordance with the preferred embodiment of the present invention used to generate motion in a curve; and - 10 - FIG.'s 13, 14, 15, 16 illustrate steps in an assembly process for a mobile phone modified to incorporate the teachings of the present invention.

Description of Preferred Embodiments

The preferred embodiment of the present invention will be described in terms of a mobile telephone. However, it will be appreciated that the inventive concept may be embodied in any other type of portable device, such as a PDA or music player.

It is also envisaged that the inventive concept of the present invention is not limited to portable devices, but is also applicable to any other system in which such a mechanism would be beneficial, such as automotive ashtrays or cup holders, SIM-card slots, storage trays, etc. In order to make mobile phone products more compact in length, but still maintain a good size display and keypad, a product type referred to as a slider phone has been gaining popularity in the market. Typically, these products comprise a bottom module 130, which contains the main mobile phone elements, such as the main printed circuit board, alphanumeric keypad and battery pack and above it sits a top module 110, which preferably contains the LCD and the navigation part of the keypad. In the closed state, the product is compact and the user is able to receive calls and make calls using the navigation keypad. If the user wants to dial out, or text, the top module can be slid forward 120 to reveal the alphanumeric keypad.

- 11 - "Semi-automatic" is the industry description of how a specific type of opening action is achieved. For semi- automatic opening the user pushes against a spring system. After some travel, the spring force switches over and the product opens without further user intervention under the action solely of the spring.

The principle components of a semi-automatic opening mechanism, according to the teachings of the current invention, are shown in FIG. 8. FIG 8 shows two modules: a first module 825, to which a torsion spring 815 is mounted via two guide pins 805, and a second module 835, which incorporates a cam profile 840, within which the guide-pins are constrained to move. The spring 815 is located mechanically to only the first module 825, its mounting position being selected primarily so as to simplify the manufacturing process and reduce the cost of the components.

When the modules are assembled together, the spring sits within the profile of the cam, i.e. within a cut-out in the second module 835. This results in a very compact structure as the spring 815 sits within the mechanism and advantageously does not increase its thickness. The cam profile 840 is also provided with recesses, in which the guide pins may sit, thus providing a detent force in the open and closed positions and increasing the perceived stiffness and rigidity of the phone. The force/ displacement profile of the device is thus defined by the spring constant of the spring 815, and the profile of the cam 840. The mechanism is modular, as one spring 815 can be used for multiple applications, simply by the - 12 - expedient of modifying the profile of the cam, which results in reduced manufacturing costs.

As shown in FIG. 8, the guide pins 805 are constrained to move into a slot 820 within the module 825. Thus, the force generated by the action of the cam profile on the guide-pins, due to relative motion of the two modules 825, 835, is elegantly resolved into a component in the direction of the slot, which compresses the torsion spring.

Also shown in FIG. 8 are two compression springs 810.

These springs, which act together, could be mechanically fixed at one end to the first module 825, and at the opposite end to the second module 835. The springs 810 compress and expand during operation of the opening mechanism to provide further mechanical assistance. They may be configured to assist in counteracting the friction of the slider mechanism and the cam/ guide-pin mechanism.

A displacement of the first module 825 with respect to the second module 835, due to an applied force 915, as shown in FIG.9, results in the cam profile forcing the guide-pins to move inwards and push the ends of torsion spring together. This continues until the cam profile has moved relative to the guide pins to the position shown in FIG.10. This is the maximum compression point of the spring 815. Any further relative displacement of the two modules 825, 835 in either direction will not result in any further compression of the spring 815.

This point is known as the switch-over point.

- 13 - If the user continues to apply a force F' 915 in FIG 9 to the second module 825, then the guide-pins will move beyond the switch-over point. Here, the cam profile widens and allows the torsion spring to relax, thereby releasing its stored energy. This provides a force in the direction of the previous applied force, F 915, and continues to open the device. Once the guide pins have reached the end of the cam 1100, as shown in FIG. 11, the device is fully open and the torsion spring is again relaxed.

FIG.'s 5-7 show schematically the basic principle of operation of the semi-automatic opening mechanism. In FIG. 5 a spring 550 is mounted between two guide-pins 520, 530, which are themselves constrained to move in a slot. The guide pins and spring are mechanically located to a first module 510. A second module 500 is provided with a cam profile that is cut out of the material of the module or formed during the manufacturing process.

The two modules 510, 500 are assembled together via a sliding mechanism to form a unit, in this case a mobile phone. Assuming that the first module is held stationary at the median position 540, then a large enough force F' applied to the second module in the direction shown in FIG. 5, will cause the guide-pins to move over the cam and compress the spring 550. Compression continues until the switch-over point of the cam is reached, as shown in FIG. 6. At this point the spring is at maximum compression, and any further motion of the second module will result in its re-expansion.

- 14 - If no further force is applied, the mechanism will remain in this quasi- stable' state. A further force applied in the direction of the original force F', shown in FIG. 5, will result in the energy stored in the spring being returned to the mechanism. This is due to the guide pins being forced along the cam profile by the expanding spring until the end of the cam is reached, as shown in FIG. 7.

The advantage of a mechanism fixed only to one module in the sliding pair can be clearly seen by reference to FIG. 12, in which the second module with the cam cut-out is not flat or planar, but curved. Using the semi-automatic opening mechanism, described in the teachings of the present invention, enables curved or even circular motion. This is made possible by the use of a cam, which allows the spring to remain in a fixed position relative to the first module, and in effect de-couples the force generation mechanism from the mechanical motion generation. The spring simply forces the secondary module to move by expanding or unwinding, and thus exerting a force on the cam via the guide-pins, while it remains stationary.

The operating mechanism remains mechanically substantially identical, whether the motion is planar, curved or circular. In effect, because the spring is fixed in position to one of the plates, and sits in free space in the opposite plate, it will allow a translation along a circular arc.

Furthermore, the spring can be attached to either plate.

Essentially, the whole mechanism can be reversed that - 15 - what is shown in FIG. 5, FIG. 6 and FIG. 7, i.e. the spring can be attached to the moving top plate and the cam profile be in the fixed plate.

The modular design of the semi-automatic opening mechanism presented in the current invention, allows a slider type mobile phone, including the semi-automatic opening mechanism, to be assembled from individual components by hand; FIG's 13-16 show the basic steps involved in the assembly process.

The two modules 1330, 1310 are assembled to each other, as illustrated in FIG. 13, where the cam cut-out provides an in-built "tooling", which allows the guide-pins 1410 to be easily assembled to the unit, as illustrated in FIG. 14. Guide rails or slides 1500 are subsequently assembled to the unit 1510 in FIG. 15, and the spring 1600 is located to the guide-pins in FIG. 16. The basic semi-automatic opening mechanism is now substantially complete and operable. Further components, such as the LCD, PCB, etc., can now be assembled onto the phone.

Thus, the spring system is easy to assemble. It allows the semi-automatic mechanism and slide rail system to be integrated into mobile phone housings and assembled on a mobile phone assembly line without the use of specialised equipment. This will have the potential to reduce cost and component count.

Whilst the specific and preferred implementations of the embodiments of the present invention are described above, it is clear that variations and modifications of such - 16 - inventive concept could be readily applied by one skilled in the art.

Thus, a mechanism for generating a semi-automatic opening action for opening of a mechanical device, having a minimum physical volume, reduced height/thickness, and providing an easily definable force/distance characteristic has been described, where the aforementioned disadvantages with prior art arrangements have been substantially alleviated. The mechanism operates by controlling the deflection of a spring with a cam, the force/displacement being adjustable to create the required profile, e. g. a short push and a long opening stroke, by adjusting the profile of the cam. The spring system is designed to be assembled easily by hand from one direction and does not require tooling or automation.

Claims

- 17 - Claims 1. Mechanism for generating a semi-automatic opening action,

the mechanism comprising at least a first and a second module operably connected via a sliding mechanism and a mechanical energy storage device characterised in that the mechanical energy storage device (815) is mechanically located (805) to only a first module (130) via at least guide-pins, a second module (110) provided with a cam (900) being mechanically located via a sliding mechanism to the first module (130), such that the guide- pins rest on the profile of the cam (900), the force/ displacement function of the mechanism being determined by the cam profile (900) and characteristics of the energy storage device.
2. Mechanism according to Claim 1 further characterised in that the mechanical energy storage device (815) is free to move substantially only in one plane.
3. Mechanism according to Claim 2 further characterised in that the plane of motion of the mechanical energy storage device is substantially the same as the plane of motion of the first and/or second module or tangential thereto.
4. Mechanism according to any preceding Claim further characterised in that the mechanical energy storage device (815) is located to the first module (130) at one or both of its ends by the guide pins (805), the guide pins being themselves located to, and constrained - 18 - to move in, a track (820), said track being substantially at 900 to the direction of motion of the first and/or second module (120)
5. Mechanism according to Claim 4 further characterised in that when the first (1330) and second (1310) modules are mated, the guide pins rest against the cam profile provided in the second module such that, relative motion of the modules causes a subsequent motion of the guide pins defined by the profile of the cam.
6. Mechanism according to Claim 5 further characterised in that each guide pin (805) performs the function of a bearing, which when the first (1330) and second (1310) modules are located together (1400), rests against the cam profile (900) and provides a low friction mechanical contact with said profile.
7. Mechanism according to Claim 5 or Claim 6 further characterised in that the first (1330) and second (1310) modules are mechanically connected via sliding coupling (1500) such that one module is free to move relative to the other.
8. Mechanism according to Claim 7 further characterised in that the sliding coupling (1500) comprises of one or more roller-bearings or ballbearings or low friction slide pins.
9. Mechanism according to any preceding Claim further characterised in that one or further energy storage device(s) (810) is/are mounted between first - 19 - (825) and second (835) modules substantially at 90 to the first energy storage device (815)
10. Mechanism according to Claim 9 further characterised in that the one or more further energy storage device(s) (810) is/are mounted coincident with a direction of motion of the first (130) and/or second (110) modules, said further energy storage device (810) being mechanically fixed at one end to the first module (825) and at the other end to the second module (835)
11. Mechanism according to any preceding Claim further characterised in that the first energy storage device (815) is a spring.
12. Mechanism according to Claim 11 further characterised in that the first energy storage device (815) is a helical spring or a torsion spring.
13. Mechanism according to any preceding of Claims 4- 12 further characterised in that the cam profile (900) is arranged with one or more, recesses (1020, 1100) provided in which the guide pins sit.
14. Wireless communication device (100) utilising a semi-automatic opening, the device (100) being constructed of two or more modules (130, 110), and characterised in that it incorporates the mechanism of any of the preceding Claims.
15. A mechanism for generating a semi-automatic opening action substantially as hereinbefore described - 20 - with reference to, and/or as illustrated by any of FIG'S to 16 of the accompanying drawings.
16. A wireless communications device substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 1 of the accompanying drawings.