WO2006012701A1

WO2006012701A1 - Rechargeable flashlight

Info

Publication number: WO2006012701A1
Application number: PCT/AU2005/001172
Authority: WO
Inventors: Peter Lynch
Original assignee: Pelena Pty Limited
Priority date: 2004-08-05
Filing date: 2005-08-05
Publication date: 2006-02-09

Abstract

A rechargeable flashlight (1) and a flashlight charger unit (2), endowed with secondary and primary inductive coupling means respectively, for charging the flashlight (1). The flashlight (1) includes a secondary induction coil and electrical storage device located in a flashlight housing (3). The flashlight charger (2) unit includes the primary induction coil located in a body. The housing (3) and body are configured for complementary engagement in a charging position whereby the primary and secondary coils are disposed in inductive proximity for energy transfer.

Description

RECHARGEABLE FLASHLIGHT

FIELD OF THE INVENTION

The present invention relates generally to rechargeable lighting devices, and more particularly to rechargeable flashlights.

BACKGROUND OF THE INVENTION

The invention has been developed primarily for use as a hand held flashlight, and will be described predominantly with reference to this application

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Battery powered flashlights are well known, and, since the advent of rechargeable batteries, flashlights powered by rechargeable batteries have become commonplace. While in some cases, the batteries must be removed from the flashlight to be charged, usually in a separate charging unit, nowadays it is common to find flashlights with integral batteries.

Such flashlights require either the use of a separate charging unit that connects to a power supply or, the flashlight itself plugs directly into the power supply.

A drawback of both systems is that they require an electrical connection to establish charging. This requires electrically conducting terminals to be located at some position on the flashlight. These connectors may results in difficulties when the flashlight is used in some environments. For instance, in wet or environments the electrical connectors may be prone to shorting out. In hazardous environments, such as flammable or explosive surroundings, the exposed electrical connectors may present a significant safety risk. In addition, if the flashlight is used in dirty surroundings, mud, dirt and debris may interfere with the connection and reduce or prevent charging. Additionally, general oxidisation of terminals may interfere with the connection and reduce or prevent charging.

Furthermore, electrical connections must be plugged or unplugged or require precise alignment which may provide a hindrance to flashlight access under emergency conditions.

It may be possible to locate the connectors within the housing so that when assembled, the entire flashlight is waterproof however, such systems would be inconvenient as they require the housing to be breached for charging and subsequent reassembly before use.

It is an object of the present invention to overcome or ameliorate one or more of these disadvantages of prior art, or at least to provide a useful alternative.

DISCLOSURE OF THE INVENTION

In a first aspect, the invention provides a flashlight and flashlight charger unit, the flashlight including: a housing; an electrically powered light emitting device; an electrical energy storage device for powering the light emitting device; a switching unit for activating the light emitting device; and a secondary induction coil located within the flashlight housing, the secondary coil for directing electrical energy to the storage device, the charger unit including: a body; a primary induction coil located within the body, the primary coil for generating a magnetic flux; and means for electrically connecting the primary coil to an electric power supply; wherein the housing and body are configured for complementary engagement in a charging position whereby the primary and secondary coils are disposed in inductive proximity for energy transfer.

Preferably, the charging position provides optimised for energy transfer. Preferably, the flashlight housing includes a shaft and the charger unit body includes a sheath for receiving and locating the shaft such that respective longitudinal axes of the shaft and sheath are substantially coaxial.

Preferably, the flashlight and the charger include mutual abutment surfaces located on an increased radius portion of the housing and an outer edge of the sheath, respectively, for longitudinally locating the shaft in the sheath in the charging position. Preferably, the charging position is independent of radial orientation of the shaft within the sheath.

Preferably, the flashlight and charger unit include respective flashlight and charger unit control systems and communication means providing for communication between the flashlight and charger unit control systems.

Preferably, the control system is responsive to the data from the communication means.

In a second aspect, the invention provides a flashlight in accordance with the flashlight of the first aspect, for use with a flashlight charger unit in accordance with the flashlight charger unit of the first aspect.

In another aspect, the invention provides a flashlight charger unit in accordance with the flashlight charger unit of the first aspect, for use with a flashlight in accordance with the flashlight of the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is a pictorial representation of a flashlight and flashlight charger unit in accordance with the invention;

Fig. 2 is a pictorial representation of the flashlight and flashlight charger unit of Fig. 1, engaged in the charging position;

Fig. 3 is a sectional schematic view of the flashlight shown in Fig 1; Fig. 4 is a pictorial view of a flashlight charger unit shown in Fig 1 ; Fig 5 is a sectional schematic view of the flashlight charger unit shown in Fig i; Fig 6 is a side view of the flashlight charger unit shown in Fig 1 ;

Fig 7 is a hidden detail front view of the flashlight and flashlight charger unit of Fig. 1, engaged in the charging position;

Fig 8 is a hidden detail end view of the flashlight and flashlight charger unit of Fig. 1, engaged in the charging position; Figs. 9 and 10 are pictorial representation of an alternative flashlight and flashlight charger unit in accordance with the invention;

Fig 11 is a detailed pictorial view of the flashlight charger unit shown in Fig 1; - A -

Fig 12 is an end view of the flashlight charger unit shown in Fig 1; and Figs. 13 and 14 are pictorial representation of another alternative flashlight and flashlight charger unit in accordance with the invention.

PREFERRED EMBODIMENTS OF THE INVENTION Referring to the drawings, and in particular to Figs. 1 & 2, the invention includes a rechargeable flashlight 1 and a flashlight charger unit 2. The flashlight 1 and flashlight charger unit 2 are endowed with inductive coupling means for charging the flashlight.

Referring to Fig. 3 the flashlight 1 includes a housing 3, an electrically powered light emitting device 4, an electrical energy storage device 5 and switching unit 6, for controlling the light emitting device 4. The flashlight 1 also includes a secondary induction coil 7 located within the housing 3 and electrically connected to the storage device 5 for directing electrical energy to the storage device 5.

Referring to Figs. 4 & 5, the flashlight charger unit 2 includes a body 8, a primary induction coil 9 located within the body 8 for generating a magnetic flux and means 10 for connecting the primary coil to an electrical power supply. The housing 3 of the flashlight 1 and body 8 of the charger unit 2 are configured for complementary engagement in a charging position, as shown in Fig. 2, 7 & 8. In the charging position, the primary and secondary coils, 7 & 9, are disposed in inductive proximity for inductive coupling and energy transfer.

An alternating (AC) electrical current in the primary coil 9 generates a magnetic flux, which, when the coils are located in inductive proximity, induces an AC electrical current in the secondary coil 7. This induced current is transformed into a DC current by a rectifier and used to recharge the electrical energy storage device. As such, the system does not require any conducting electrical contact between the flashlight and charging supply. However, it is true that energy transfer efficiency is highly dependant on the orientation and displacement between the primary and secondary coils. Hence, the charging position locates the coils in close inductive proximity for optimised energy transfer. To further enhance inductive energy transfer, a ferritic or other material, 11, may be incorporated in the flashlight adjacent the secondary coil. The charger unit 2 not only provides charging for the flashlight 1 but also provides a convenient means of storage. To this end, the charger unit 2 may take a variety of forms including a cradle, tray, holster, rack or hook and may be wall mounted, free standing or adapted for bench to use. However, in this embodiment, as shown in the figures, the charger unit body includes a sheath 12 for receiving and locating a complementary shaft 13 of the flashlight housing. The shaft and sheath are dimensioned with respective diameters to provide adequate clearance for easy insertion, yet maintain the coils, 7 & 9, in close proximity. In effect, as shown in Fig. 1, the respective longitudinal axes 14 of the shaft and sheath are substantially collinear and, the flashlight and flashlight charger unit are provided with linear, one directional "drop-in" or "slide-in" engagement and removal. m this embodiment, the flashlight and flashlight charger unit include mutual abutment surfaces, respectively located on a bulbous head 15 and a support ring 16. As can be seen, the bulbous head 15 abuts with the support ring 16 to prevent the flashlight falling completely through the charger unit.

Of course it will be appreciated that in other embodiments the mutual abutment surfaces may be embodied in a variety of ways without departing from the invention. These may include, frusto-conical cross sectional housings and corresponding sheaths, closed or partially closed bottom ends to the sheath, hooks, protrusions or formations on the flashlight and/or charger unit.

It will be appreciated, as can be seen in Fig. 7, with the shaft located in the sheath, the abutment surfaces provide longitudinal positioning such that the primary coil 9 and secondary coil 7 are adjacent one another in the charging position. Furthermore, because the sheath surrounds the shaft, the primary coil 9 in the charger unit may be configured to completely surround the secondary coil 7 in the flashlight. Given that the shaft and sheath are generally circular cross-section, both coils may be symmetrically disposed around the respective longitudinal axes of the shaft and sheath, thereby removing any requirement for the user to consider radial alignment when engaging the flashlight in the charger unit.

Accordingly, the flashlight is adapted for insertion and removal by linear one- directional motion which does not necessitate altering the one-handed-hold usual for carrying and operating the flashlight. In addition, removal of the flashlight requires no manual unclipping and can be performed by pulling on the flashlight body or handle. This enables the flashlight to be easily and expediently removed from the unit in emergency situations.

The flashlight housing may include a single unit compartment, several connected compartments or include compartment separated by bulkheads. For instance, Fig. 3 shows the housing 3 split by bulk head 17, into electrical storage and induction coil compartments, 18 & 19, respectively containing the electrical storage device and secondary induction coil. In addition the housing is waterproof and sealed to prevent ingress of outside elements such as dirt, fluids or gasses. Sealing the flashlight and/or the charger unit also provides several other advantages. Sealing allows the flashlight and/or the cradle to be disinfected or otherwise cleaned with liquid, and/or sterilised by heat. This ability may be particularly useful in medical or research institutions where biohazards exist and there are often multiple users of the same flashlight. Furthermore, the device may be sealed for life or have a manufacturer's sacrificial component to allow for professional refurbishment only. Limitation of refurbishment of the flashlight by authorised service departments may be desirable if they are to be used in hazardous environments.

In other embodiments, such as that shown in Figs. 9 & 10, the flashlight includes a handle 20 attached to the housing. To accommodate the handle, the sheath includes a corresponding longitudinally extending slot 21. Figs. 9 & 10, also show an alternative shaped housing and corresponding body, whereby the sheath and shaft include alignment formations 22 & 23, for multi-positional radial alignment. It will be appreciated that in this design the inductive charging coils do not completely surround the flashlight. Instead, the flashlight charger unit, incorporates semi-circular or planar primary coil arrangement to suit the physical nature of the flashlight body.

The length and shape of the flashlight housing 3, may differ depending on the size and shape of the internal components, such as the energy storage devices 5. For instance, additional energy storage devices, which result in a flashlight of extended length may be required to provide the flashlight with an extended operational run¬ time. The shaft / sheath configuration allows a single flashlight charger unit to be capable of charging different length and shape flashlights. In another embodiment shown in Figs, 13, & 14, movable flaps and may be used to secure the flashlight. These flaps automatically move from an open position as shown in Figure 13, where they act as guides to aid alignment of the flashlight with the holster, to a closed position, shown in Figure 14, where they releasably contain and locate the flashlight within the charger unit. The flaps are moved between the closed and open positions automatically upon insertion and removal of the flashlight, respectively.

In other embodiments, the charger unit may be provided with additional securing means to prevent the flashlight jumping out of the holster in rough condition such as use on a boat, vehicle or aircraft. The securing means may be a hard and fast mechanical device or a soft shock/energy absorbing material.

In addition, the charger unit and flashlight are designed to prevent dirt and foreign material from interfering with mutual engagement. For instance, the sheath and/or flashlight include wipers 24 to brush or wipe fluid and debris from the externally surfaces of the flashlight should it be soiled or wet when inserted in to the holster. Drainage conduits or voids are located to channel debris and fluid away from the flashlight charger unit interface. The wipers, channels and voids prevent foreign matter from interfering with the engagement of the flashlight to the charger unit thereby maintaining alignment of the primary and secondary coils. The additional drag caused by the wipers may also serve to prevent the flashlight jumping from the charger unit. The flashlight and charger unit

The flashlight housing and charger unit body may also include various other components such as control circuitry, sensors, communication means and other components which will be described in more detail, hi general, there may be several alternatives for each of the components which by and large perform the same task. It will be appreciated that various combinations of components may be combined to produce the same or a similar result, without departing from the scope of the invention. Light Emitting Device The light emitting device 4 includes a white LED 25 (light emitting diode).

However, other colours or a combination of different colour LED's maybe used. Similarly, the light emitting device may include any other type, or combination of illumination means in place of the LED, without departing from the scope of the invention. For instance, a normal incandescent bulb, halogen bulb, fluorescent bulb/tube or metal halide, light emitting device may be used.

In this embodiment, the light emitting device also includes a reflector 26 device for focussing emitted light. In addition, the light emitting device may be provided with adjustable focussing means for adjusting the spread of emitted light. Electrical Energy Storage Device

The electrical energy storage device 5, could be, but not is limited to, any one or a combination of: lead acid battery, aNiCad (nickel-cadmium) battery, a NiMH (nickel-metal-hydride) battery, lithium ion battery, a capacitor, or any other rechargeable battery device.

It is desirable to select a battery which exhibits little memory effect so that the flashlight is capable of being removed and replaced to the charger unit or "stored" indefinitely and without subject to any battery-specific charging procedures. Alternatively, the flashlight and/or charging unit may include a charging control device to monitor and carefully control the charging cycle of the battery thereby reducing the impact of battery memory effects.

Other battery specific traits must also be considered. For instance some batteries exhibit superior energy density (Joules or Amp-hours per kg) ratings and cycle lives. Some battery types such as (at least) SLA (sealed lead acid) and NiCad batteries can release hydrogen when being charged. This can pose a hazardous situation inside the flashlight due to the possible ignition of these gases. Should this type of battery be used it may be necessary to equip the flashlight with a system for controlling the hydrogen build up, particularly if the housing is otherwise sealed. This may be by means of a hydrogen absorbing means such as hydrogen-absorbing capsules.

The flashlight may be provided with a pressure relief valve 27 to prevent pressure build up. Apart from pressure build-up due to charging gases, there are two other main reasons for gas build-up. One is when the flashlight is taken to a lower atmospheric environment, for instance high altitude. The other is when the flashlight, for whatever reason, leaks water into the casing and into the batteries. The batteries can then decompose and release excessive gases which can result in the flashlight exploding. Accordingly, the pressure relief valve to automatically reduce pressure within any one of the sealed housings, as required. Control System

The flashlight and/or remote charge may be equipped with a charging and discharging control system. The control system is designed to protect and prolong battery life. For instance, the control system may be configured to prevent full discharge of the battery which may be harmful to some rechargeable battery types. It may also provide warning to the user that the flashlight is low on power. The warning may involve an audible or visual indicator. A state of charge indicator comprising one or more LEDs may be included on the flashlight and/or on the charger unit, shown as 28 & 29 respectively. The control system may also be configured to control the charging cycle by managing the rate of charge. For instance, the control system may reduce the charging rate as the battery nears full charge, hi some battery types this helps to achieve a "full" charge of the battery. In other cases the control system may pulse charge the battery to maintain full charge if the flashlight is unused for an extended period. Again, a state of charge indicator may be located on the external surface of the charger unit so that the level of charge of the battery can be easily determined by the user.

The control system may also allow for the connecting to various power supplies including but not limited to, mains supplies, generator supply, vehicle electrical systems or solar photovoltaic systems. The control system may be provided with appropriate means to cope with variation in current, amperage and/or frequency of such alternative power supplies. For instance, when the supply voltage reaches a first pre-set level, the control system may be configured to turn on for the required period to allow flashlight charging. Should the voltage then decrease to a second preset level, the charger may be configured to disconnect or significantly reduce the power drawn from the main supply. This may prove useful when operating from a solar photovoltaic or vehicular supply.

In further embodiments, the control system may include complementary flashlight and charger unit control systems 30 & 31, for controlling charging and/or the light emitting device. The control system may also include sensor means, the control system being responsive toward the sensing means. In a simple form the sensor may comprise a simple mechanical switch detecting whether an object is in the charger unit and switch the primary coil on or off as appropriate. In a more sophisticated embodiment, the sensor means may include electronic communication means in the flashlight and charger unit, 32 & 33. The communication means may confirm not only that an object is located in the storage device, but also that the object is a compatible flashlight. This provides an important safety feature to ensure that the primary coil is active only when appropriate. Other information which may be communicated by the communication means may include: correctly positioned engagement of flashlight and charger unit; level of charge of the electrical energy storage device; type of flashlight in the charger; type of electrical energy storage device; and/or availability of electrical power supply. The control system may react in response to this date by modifying charging cycles or alerting the user via visual or audible signals. For instance, the flashlight may be set such that it automatically turns on when either the mains power is terminated, the flashlight is removed from the cradle, or remotely from a switched device, such as the opening of a normal light-triggered vehicle or other door etc. Switching Unit

In this embodiment, the switch 6 to turn the light on or off is of the non-contact type such that there is no physical connection between the external operated mechanism and the internal electrical breaker/switch. The flashlight case integrity is therefore not breached. However, virtually any type of electrical switch may be used. This would include simple contact switches and more sophisticated electrical touch pads. The switching unit may also be incorporated into the control system.

It will be appreciated that because the flashlight is totally sealed, and has no exposed electrical terminals, it is particularly suited to usage in extreme environments. Moreover, the combined charger/storage unit allows for rapid access to the flashlight in emergency situations. In particular, it should be noted that the recharging operation is conducted without breaching the sealed flashlight casing.

It will be appreciated that the invention provides a rechargeable flashlight with electrical contactless charging. The charging system allows a sealed flashlight for use in extreme, muddy, hazardous and wet environments which is convenient to use. In all these respects, the invention represents practical and commercially significant improvement over the prior art. Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A flashlight and flashlight charger unit, said flashlight including: a housing; an electrically powered light emitting device; an electrical energy storage device for powering the light emitting device; a switching unit for activating the light emitting device; and a secondary induction coil located within the flashlight housing, said secondary coil for directing electrical energy to the storage device, said charger unit including: a body; a primary induction coil located within the body, said primary coil for generating a magnetic flux; and means for electrically connecting the primary coil to an electric power supply; wherein the housing and body are configured for complementary engagement in a charging position whereby the primary and secondary coils are disposed in inductive proximity for energy transfer.

2. A flashlight and charger unit according to claim 1 wherein said charging position provides optimised for energy transfer.

3. A flashlight and charger unit according to claim 2 wherein said flashlight housing includes a shaft and said charger unit body includes a sheath for receiving and locating said shaft such that respective longitudinal axes of said shaft and sheath are substantially coaxial.

4. A flashlight and charger unit according to claim 3 wherein said flashlight and said charger include mutual abutment surfaces for longitudinally locating the shaft in the sheath in the charging position.

5. A flashlight and charger unit according to claim 4 wherein said abutments surfaces are located on an increased radius portion of said housing and an outer edge of said sheath, respectively.

6. A flashlight and charger unit according to any one of claims 3 to 5 wherein said charging position is independent of radial orientation of the shaft within the sheath.

7. A flashlight and charger unit according to claim 4 wherein said sheath includes a longitudinally extending slot.

8. A flashlight and charger unit according to any one of the preceding claims further including a control system.

9. A flashlight and charger unit according to claim 8 wherein the control system includes sensor means, said control system responsive to said sensor means.

10. A flashlight and charger unit according to claim 8 or 9 wherein the control system includes respective flashlight and charger unit control systems.

11. A flashlight and charger unit according to claim 10 wherein said sensor means includes communication means providing for communication between said flashlight and charger unit control systems.

12. A flashlight and charger unit according to claim 11 wherein said communication means transfers data including one of more of: authentication of flashlight; correct engagement of flashlight and charger unit; level of charge of the electrical energy storage device; availability of electrical power supply.

13. A flashlight and charger unit according to claim 12 wherein said control system is responsive to the data from the communication means.

14. A flashlight and charger unit according to any one of the preceding claims wherein the charger unit includes wiper means for wiping the flashlight housing upon engagement.

15. A flashlight including: a housing; an electrically powered light emitting device; an electrical energy storage device for powering the light emitting device; a switching unit for activating the light emitting device; and a secondary induction coil located within the flashlight housing, said secondary coil for directing electrical energy to the storage device, said flashlight for use with a charging unit including: a body; a primary induction coil for generating a magnetic flux; and means for electrically connecting the primary coil to an electric power supply; wherein the housing and body are configured for complementary engagement in a charging position whereby the primary and secondary coils are disposed in inductive proximity for energy transfer.

16. A flashlight charger unit, said charger unit including: a body; a primary induction coil located within the body for generating a magnetic flux; and means for electrically connecting the primary coil to an electric power supply; said charger unit for use with a flashlight, said flashlight including: a housing; an electrical energy storage device for powering a light emitting device; and a secondary induction coil located within the flashlight housing, said secondary coil for directing electrical energy to the storage device, wherein the housing and body are configured for complementary engagement in a charging position whereby the primary and secondary coils are disposed in inductive proximity for energy transfer.