WO2005078904A1

WO2005078904A1 - Flashlights

Info

Publication number: WO2005078904A1
Application number: PCT/AU2004/000997
Authority: WO
Inventors: Peter James Boyle; Xue Wanzheng; Shao Dongsheng; Jack Lin Xiao Lin
Original assignee: Peter James Boyle; Xue Wanzheng; Shao Dongsheng; Jack Lin Xiao Lin
Priority date: 2004-02-16
Filing date: 2004-07-23
Publication date: 2005-08-25

Abstract

A manually powered flashlight (1) includes a light source (7), such as a LED light source, powered by an electrical storage element, such as a one-farad capacitor, that is charged from a generator (5), such as a three-phase generator, through suitable regulator circuitry (6). The generator (5) is driven manually, such as by a drive spool (9) and pull cord (13), and via a transmission, including gears (14, 16 and 17), that steps up the rotational speed.

Description

Flashlights

The p'resent invention relates to flashlights, also known as torches. Flashlights are ubiquitous devices of great utility. They are of use both indoors and outdoors, e.g. during a blackout or when camping or the like, and are almost universally owned. The majority of flashlights are powered by a set of dry cell batteries. Dry cell batteries, however, have a limited lifetime and are made of toxic chemicals. They also need to be continually manufactured, replaced and disposed of. They are therefore environmentally unfriendly, especially as they are often not disposed of with care. These problems have been addressed somewhat by the use of rechargeable storage batteries, but only to a limited extent. Further, both types of battery tend to make flashlights heavy, and the need to replace or recharge batteries can be inconvenient and in some situations, e.g. in the field, impossible. An aim of the present invention is to provide a novel flashlight having a number of advantages in its various novel features. Viewed from one aspect, the present invention provides a flashlight including a light source and a power unit for the light source, wherein the power unit includes a generator for generating electrical energy, a storage element for storing electrical energy generated by the generator for supply to the light source, and a driver mechanism for driving the generator, the driver mechanism including a hand-powered mechanism. The present invention thus provides a flashlight that is manually powered. It can therefore do away with the need for replacement batteries or for a power source to recharge batteries, and is much more environmentally friendly. It can be lightweight and inexpensive to use, and is especially useful in the field, e.g. away from battery supplies and power supply points. All that is required to power the flashlight is for a user to drive the generator manually to charge up the storage element. The user may then e.g. activate a suitable switch to connect the light source and storage element together to provide the desired flashlight beam. The storage element may take any suitable form and could for example be a storage battery. In a preferred form, however, the storage element is a capacitive element, e.g. a storage capacitor. In this case, there is no need for batteries, and the capacitor may provide a flashlight with long life that does not need replacement parts. A suitable capacitor might for example be rated at between about 1 and about 5 farad, and, in one preferred embodiment, a capacitor of about 1 farad is used. The light source may also take any suitable form, and could in some circumstances be e.g. a miniature incandescent bulb. Preferably, however, the light source includes a light emitting diode source (LED). A LED source may provide long life without replacement. It may also be of high efficiency and low power consumption, so that a user can easily generate sufficient energy manually to power the light source. The LED source may take any suitable form, and may include one or more LED elements, e.g. in a cluster or a row. The LED source may include e.g. a white light source. It may include a high brightness LED source, e.g. of about 15 cd or more output. The drive mechanism may take any suitable form, and may include e.g. a crank handle. In a particularly preferred embodiment, however, the drive mechanism includes a drive spool that is rotated by a pull cord wound about the spool. Thus, in order to generate electricity, a user would pull the cord, thereby unwinding the cord from the spool and rotating the spool. This rotation would then be transferred to the generator. The use of a drive spool and pull cord can have a number of advantages. It can lessen the manual effort of charging the flashlight, and can provide a comfortable action. In a particularly preferred embodiment, the pull cord of the drive spool extends in use from an opening in the rear of the flashlight housing. This again provides for an effective and streamline design of flashlight, and allows the cord to be easily and comfortably pulled whilst holding onto the main shaft of the flashlight housing within which the power unit is mounted. The cord could however also extend transversely to the flashlight housing, e.g. from a side opening. Preferably, the pull cord is attached to a plug element that closes an opening in the flashlight housing through which the cord extends, e.g. in the end of the housing. Thus, when the pull cord is not needed, it may be stored away neatly in the flashlight housing. Preferably, the plug element seals the opening so that the flashlight is waterproof. The plug element may be threaded so as to screw into the pull cord opening to hold it fast in place. Preferably, the spool includes a rewind element for storing mechanical

(potential) energy during extension of the pull cord and for retracting the pull cord after extension of the cord. The rewind element may be in the form of a spring, e.g. a helical spring. It may for example be mounted between a central axle of the spool and the spool body. The rewind element may wind-up as the cord is pulled off of the spool, and may relax when the tension on the extended cord is released, so as to rotate the spool body about the axle in the opposite direction to the cord pull-off direction, and wind-up the pull cord. Preferably, the spool drives the generator to generate electricity during both extension of the cord and retraction of the cord, and preferably the rewind element, e.g. spring, is sized so as to store enough energy during the pulling of the cord, so that it is able to both retract the cord and drive the generator through the spool at a suitable speed for meaningful energy generation. The drive mechanism may act directly on the generator, e.g. the drive spool may be a part of the generator rotor. Preferably, however, the power unit includes a transmission mechanism between the drive mechanism and generator. Preferably, the generator is rotated at high speed, and the transmission mechanism is preferably a speed step-up transmission, so that a slower rotation of the drive mechanism can translate to a higher speed rotation of the generator. The rotation of the generator at high speeds can allow a smaller and more compact generator to be used, whilst the use of the step-up transmission means that a spool of convenient size can also be used without requiring a user to pull the cord at an uncomfortable rate. The drive and transmission mechanisms may for example drive the generator at between about 2000 and about 3000 revolutions per minute, and, in a preferred embodiment, the generator is driven at about 3000 revolutions per minute. The transmission preferably provides a step-up ratio of between about 1 :3 to about 1 :5, and, in a preferred embodiment, provides a step-up ratio of about 1 :3, so that the generator is rotated at about three times the rate of the drive spool. Preferably, the generator is designed so as to require only a low torque input, as a step-up in speed through a transmission will generally provide a step-down in torque. The generator preferably has a small moment of force, with the force on the pull line for turning the generator being small too (e.g. the power for switch on may be e.g. 100 cm/g). Preferably, the transmission mechanism includes a set of gears. When using a drive spool and pull cord, in a preferred embodiment, the transmission mechanism includes a large diameter gear associated with the drive spool, and a small diameter gear associated with the generator. Preferably, also, there is an intermediate gear between the drive spool and generator gears. In one preferred embodiment, the drive spool gear is integral with the spool, e.g. is a moulded part of the spool. The drive spool and generator could be mounted co-axially, but preferably are mounted adjacent one another with their rotational axes parallel to each other, as this may provide for a compact arrangement. They may be configured so as to have substantially the same diameter and similar heights. The transmission gears may be mounted substantially in a common plane above the main bodies of the generator and drive spool. Thus, in a particularly compact form, the drive spool, generator and a circuit board on which electrical regulating circuitry and the storage element are mounted, are mounted in-line with one another on an elongate base plate, the rotational axes of the generator and drive spool being transverse to the plane of the base plate. The generator may take any suitable form. It may for example be a DC generator including a mechanical commutator. Preferably, however, the generator is an alternator, preferably a three-phase alternator. Preferably, the power unit includes a rectifying circuit between the alternator and storage element, e.g. capacitor. The rectifying circuitry may take any suitable form and could be e.g. a half-wave rectifier. Preferably, however, the rectifier is a full- wave rectifier. It may be e.g. a diode rectifier. The generator may for example output about 8 V AC, whilst the circuitry may change this to about 11 V DC. In a preferred embodiment, the flashlight includes circuitry for providing an auxiliary charging output for an external device. Thus, it may have a socket on its side for connection to an electrical port of another device. In a particularly preferred embodiment, the external output may be suitable for charging a mobile phone. Thus, instead of or as well as charging the storage element in the flashlight, the power unit may allow for the charging of an external device through the auxiliary output. The charging up of e.g. a mobile phone in this manner may be mainly for emergency purposes, e.g. if a user were in an emergency situation in a remote location. Most likely, in such a scenario, the mobile phone will not have been charged for some time, and so will have no power. However, the flashlight generator may be used to charge the mobile phone at least sufficiently to initiate an emergency call. As a user will generally always have a flashlight when in the field or the like, the use of the present flashlight may provide an ability to recharge a mobile phone or the like, without needing to carry further equipment, and makes for a particularly useful device. Viewed from another aspect, the present invention provides a hand- powered flashlight including a light source and a power unit, wherein the power unit includes an electrical storage element charged by a generator (e.g. having low torque and high speed characteristics), and wherein said generator is driven by a drive spool that is rotated by a pull cord provided about the spool. Viewed from another aspect, the present invention provides a hand- powered flashlight including a light source and a power unit, wherein the power unit includes an electrical storage element charged by a three-phase manually- driven alternator and a rectifier circuit. Viewed from another aspect, the present invention provides a hand- powered flashlight including an LED light source, a storage capacitor for supplying electricity to said LED light source, an alternator and rectifier for charging said capacitor, and a manually powered drive mechanism for powering said alternator. Viewed from another aspect, the present invention provides a hand- powered flashlight including a light source, an electrical storage element for supplying electricity to said light source, a generator for charging said storage element, and a manually powered drive mechanism for powering said generator, wherein said drive mechanism includes a mechanical storage element, e.g. a spring element, that stores mechanical energy on manual activation of the drive mechanism, so that after said manual activation, said mechanical storage element can drive said generator using said stored energy. Viewed from another aspect, the present invention provides a hand- powered flashlight including a light source and a power unit, wherein the power unit includes a low torque, high speed generator driven by a drive spool and pull cord via a speed step-up transmission. Although the present invention has been described above solely in relation to flashlights, the present invention may also have broader application to any electronics device that requires electrical power. Thus, viewed from a further aspect, the present invention provides a hand-powered electronic device utilising the power unit of any of the above aspects, e.g. the power unit including a generator and a drive spool and pull cord for driving said generator. These devices could include e.g. a mobile phone, a laser pointer in which the light source is a laser diode, or an audio device, e.g. a radio, mp3 player or the like. The present invention also provides a power unit of any of the above aspects, which can be used with an electrical device, e.g. the power unit including a generator and a drive spool and pull cord for driving said generator. This may be a separate power unit, e.g. a separate recharger unit, or may be a manufacturing part for inclusion integrally into a final electronic product. It should be noted that the features of any one of the aspects mentioned above may be used in relation to any of the other aspects mentioned above, as appropriate. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings. It is to be understood that the particularity of the drawings does not supersede the generality of the preceding description of the invention. In the drawings: Figure 1 is a plan view of the internal components of a flashlight in accordance with one embodiment of the present invention mounted on a base plate; Figure 2 is a cross-sectional side view through line A-A of Fig. 1 , and also showing a flashlight housing in phantom about the components; and Figure 3 is a diagram of a circuit that may be used in the flashlight of Figs. 1 and 2. Referring to Figs. 1 and 2, a manually powered flashlight 1 includes a housing 2, e.g. of moulded plastics, within which are mounted lighting and power components on an elongate base plate 3. The flashlight 1 includes a manual drive mechanism 4, a generator 5, regulating and storage circuitry 6 and a light source 7. Thus, manual activation of the drive mechanism 4 causes rotation of the generator 5, which generates electricity that is regulated and stored in the circuitry 6 for supply to the light source 7 when a switch 8 is activated. The drive mechanism 4 includes a drive spool 9 mounted on the base plate 3 about an axle 10. The drive spool 9 has a helical spring 11 mounted between it and the axle 10, a narrow channel 12 about which a pull cord 13 is wound, and a gear ring 14. The spool 9 can be a plastics moulded body of which the gear ring 14 is integral. In use, the cord 13 is pulled out from the flashlight, so as to rotate the spool 9 and wind-up the spring 11. The gear ring 14 thus turns a rotor 15 of the generator 5 via an intermediate gear 16 and a gear 17 mounted on the generator rotor 15. The gears 14, 16 and 17 provide a transmission mechanism. The gear

14 has a larger diameter than the gear 17 so as to step-up the output rotational speed of the drive spool 9 by a factor of about three, and so as to turn the generator rotor 15 at a relatively high speed. The intermediate gear 16 provides a suitably sized link between the two main gears .14, 17. When a user stops pulling on the cord 13, the helical spring 11 , which has been wound up by the rotation of the spool 9, causes the spool 9 to rotate in the opposite direction. This rotation not only winds the cord 13 back onto the spool 9, but also causes the spool 9 to again drive the generator 5 via the transmission gears 14, 16 and 17 (this time in the opposite direction). Thus, the generator 5 is driven to generate electricity both when the pull cord 13 is unwound from the spool and when the pull cord 13 is wound onto the spool 9. It should be noted that the spool spring 11 will be suitably chosen so that enough potential energy is stored in the spring, during the pulling of the cord 13, to both rewind the cord 13 and drive the generator 5 at a suitable speed for electricity generation. Also, the circuitry 6 is designed to provide the same polarity electricity for storage no matter the direction of rotation of the generator 5. The generator 5 is a three-phase alternator that is designed for highspeed rotation and to have low torque. This may allow the alternator to generate sufficient electrical energy for the flashlight whilst remaining relatively small and compact. It may for example be designed to generate about 8 V AC when rotated at about 3000 revolutions per minute. As will be noted from the drawings, the drive spool 9 and generator 5 are mounted adjacent one another, with their axes parallel and transverse to the plane of the base plate 3. They may also be designed to be of the same approximate width, and to have similar heights. This construction may provide a compact and streamlined shape, that allows for a conveniently small size of flashlight, if desired. The circuitry 6 is also mounted in-line with the generator 5 and drive spool 9, and the gears 14, 16 and 17 are mounted in a common plane, above the spool and generator. The flashlight may include other features also. It may include for example a lens 18 and a cap 19 for closing the housing 2. Suitable seals may be provided to make the flashlight watertight. The LED 7 may be surrounded by a suitable reflector 20, and a suitable press button 21 may be provided to activate the switch 8. During construction, the base plate 3 and componentry may be front- loaded into the flashlight housing 2 before the fitting of the lens 18 and cap 19. The pull cord 13 may be threaded through a suitable opening in the housing 2, which is preferably in the rear of the housing. A plug member 22 may be mounted on the end of the pull cord 13, so that it can close the pull cord opening. Preferably the plug 22 seals the opening to provide a watertight housing, and e.g. could include an o-ring seal. It may include a threaded portion to hold it in place on the housing 2. The flashlight circuitry 6 is shown in Fig. 3. It includes a three-phase full- wave diode rectifier 30 that receives the output of the generator 5, a filter 31 , and an integrated circuit 32 for voltage stabilisation (e.g. a USM 7806 3-terminal positive voltage regulator). The circuitry 6 also includes a storage element 34, which may be e.g. a storage capacitor, e.g. a 1 to 5 farad capacitor, e.g. a one- farad capacitor. The capacitor 34 receives charge from the rectification and stabilisation circuitry, and then supplies the charge to the light source 7, e.g. a LED, such as a high power white LED, when the switch 8 is moved from the position shown in Fig. 3 to connect the contacts 8a and 8b. A capacitor 35 provides further filtering, whilst a diode 36 separates the charging circuit from the discharging circuit. As well as providing a power source for the light source 7, the drive mechanism 4 and generator 5 can also be used to recharge an external device, for example a mobile phone. Thus, the flashlight may have a socket (not shown) on its housing with which the recharge lead of a mobile phone may connect. This is shown schematically in Fig. 3, in which a mobile phone battery 37 is shown connected to the charging circuitry of the flashlight via diodes 38 and an auxiliary charging output connection 39. When the switch 8 connects the contacts 8a and 8c, the driving of the generator 5 will charge up an external device connected to the auxiliary charging output 39. The ability to use the flashlight to charge a mobile phone is particularly advantageous in remote situations, where power supplies will not be available and so mobile phones will often be uncharged. A user in the field can use the flashlight that they will in any case be carrying as a ready power supply, without needing to carry extra equipment, batteries or the like. The provision of the pull cord opening at the rear of the flashlight housing provides a particularly advantageous arrangement, in which the shaft of the flashlight can be held firmly whilst pulling on the cord 13. Overall, the present invention provides an environmentally-friendly device that is compact, lightweight and easy to carry, and that is inexpensive and simple to manufacture. It needs no batteries or external power supplies, and may have a long lifetime. The manual effort to charge the flashlight need not be excessive, and recharging need not be overly noisy. A flashlight in accordance with the described embodiment has been found to work in excess of 10 minutes with only 25 pulls of the cord. It is to be understood that various alterations, additions and/or modifications may be made to the parts previously described without departing from the ambit of the present invention, and that, in the light of the above teachings, the present invention may be implemented in a variety of manners as would be understood by the skilled person. For example, the storage element could be a storage battery instead of a capacitor, and the light source could be e.g. a miniature incandescent bulb or e.g. a laser diode. Also, instead of the drive spool, the generator could be turned by a crank handle or the like. The generator could have a mechanical commutator and provide DC power. The pull cord opening could be in the side of the housing, so that a user pulls the cord out transversely from the longitudinal axis of the flashlight. Other gearing or transmission systems and ratios could be used. Also, the present power unit may be provided in any suitable electronic equipment as an alternative power source. Thus, the power unit could be provided in e.g. an audio device, e.g. a radio, mp3 player or the like. The power unit may be provided as a separate component, e.g. as a separate power source or recharger.

Claims

1. A flashlight including a light source and a power unit for the light source, wherein the power unit includes a generator for generating electrical energy, a storage element for storing electrical energy generated by the generator for supply to the light source, and a driver mechanism for driving the generator, the driver mechanism including a hand-powered mechanism.

2. The flashlight of claim 1 , wherein the generator includes an alternator, and wherein said power unit includes a rectifying circuit between the alternator and storage element.

3. The flashlight of claim 2, wherein said alternator includes a three-phase alternator.

4. The flashlight of claim 2 or 3, wherein said rectifier includes a full-wave rectifier.

5. The flashlight of any preceding claim, wherein said storage element includes a capacitive storage element.

6. The flashlight of any preceding claim, wherein the drive mechanism includes a rotatable spool about which is wound a pull cord.

7. The flashlight of claim 6, wherein said spool includes a rewind element for storing mechanical energy during extension of the pull cord and for retracting the pull cord after extension of the cord.

8. The flashlight of claim 7, wherein said rewind element includes a helical coil.

9. The flashlight of claim 7 or 8, wherein the rewind element drives the generator to generate electricity during retraction of the cord.

10. The flashlight of any one of claims 6 to 9, wherein said pull cord extends from a rear of a housing of the flashlight.

11. The flashlight of any one of claims 6 to 10, wherein said pull cord is attached to a plug member, the plug member closing an opening in a housing of the flashlight through which the pull cord extends when being pulled.

12. The flashlight of any preceding claim, including a speed step-up transmission mechanism between the drive mechanism and the generator.

13. The flashlight of claim 12, wherein said transmission mechanism includes a first gear mounted on a drive spool of the drive mechanism and a second gear mounted on a rotor of the generator, the first gear being larger in diameter that the second gear.

14. The flashlight of claim 13, wherein said first gear is an integral part of said drive spool.

15. The flashlight of any preceding claim, wherein said light source includes one or more light emitting diodes.

16. The flashlight of any preceding claim, including an output for electrically coupling the power unit to an external device.

17. The flashlight of claim 16, wherein said output is suitable for charging a mobile phone.

18. The flashlight of any preceding claim, wherein said drive mechanism includes a drive spool and pull cord, and wherein said generator and said drive spool are mounted to a base plate adjacent one another and with their rotational axes parallel to one another.

19. The flashlight of claim 18, including a transmission gear mounted on each of the generator and drive spool, wherein an intermediate gear is mounted between the generator and spool gears, and wherein the three gears lie in a common plane.

20. The flashlight of claim 18 or 19, wherein said generator and spool are mounted on an elongate base plate, and wherein electrical regulating circuitry is mounted on said base plate in-line with said generator and spool.

21. A hand-powered flashlight including a light source and a power unit, wherein the power unit includes an electrical storage element charged by a generator, and wherein said generator is driven by a drive spool that is rotated by a pull cord provided about the spool.

22. A hand-powered flashlight including a light source and a power unit, wherein the power unit includes an electrical storage element charged by a three-phase alternator and a rectifier circuit.

23. A hand-powered flashlight including an LED light source, a storage capacitor for supplying electricity to said LED light source, an alternator and rectifier for charging said capacitor, and a manually powered drive mechanism for powering said alternator.

24. A hand-powered flashlight including a light source, an electrical storage element for supplying electricity to said light source, a generator for charging said storage element, and a manually powered drive mechanism for powering said generator, wherein said drive mechanism includes a mechanical storage element that stores mechanical energy on manual activation of the drive mechanism, so that after said manual activation, said mechanical storage element can drive said generator using said stored mechanical energy.

25. A hand-powered flashlight including a light source and a power unit, wherein the power unit includes a low torque, high speed generator driven by a drive spool and pull cord via a speed step-up mechanism.

26. A hand-powered electronic device including a power unit, the power unit including a generator and a drive spool and pull cord for driving said generator.

27. A power unit for an electrical device including a generator and a drive spool and pull cord for driving said generator.

28. A flashlight substantially as hereinbefore described with reference to the accompanying drawings.

29. A power unit substantially as hereinbefore described with reference to the accompanying drawings.