GB2342514A

GB2342514A - Portable electrical equipment

Info

Publication number: GB2342514A
Application number: GB9922753A
Authority: GB
Inventors: Paul Turner
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-24
Filing date: 1999-09-24
Publication date: 2000-04-12
Also published as: GB9922753D0; GB9820827D0

Abstract

A portable electrical device 1 such as a CD player, mini-disc player or the like has two batteries 2, 4 which can each power the device individually and a manually operable switch 16 to switch between the two. When one of the batteries has run flat, the switch is operated to switch over to the second battery.

Description

Portable Electrical Equipment The present invention relates to portable electrical equipment and in particular to portable audio equipment or visual equipment which is powered by batteries.

The growth in use of battery powered portable equipment such as personal cassette players, personal CD players and radios to name but a few has continued steadily in recent years. The power requirements of such devices has also increased as has consumer demands for increased battery life. This has driven significant improvements in both battery power and battery life.

However, the problems of battery life and the consequent inconvenience of having to change batteries remain.

Furthermore, the increased use of microchips to control such equipment digitally in recent years means that many items of portable electrical equipment have a sharp threshold of required supply voltage, with the problem that the equipment will function correctly whilst the battery voltage is above the threshold, but will stop operating abruptly when the threshold is crossed. This problem is exacerbated by the recent tendency in battery design to match this by increasing the power and life of batteries, but at the expense of a sharper decrease in performance at the end of the battery's useful life. The result of this is that it is becoming increasingly common for battery operated equipment to stop operating suddenly, rather than the previously more common symptom that performance of the equipment would decline gradually towards the end of the battery's life, indicating to a user that the batteries require replacement.

In accordance with the present invention there is provided a portable electrical device comprising a first power source and a second power source, said first and second sources providing sufficient power individually to operate the device and manually operable switching means for switching the electrical input to the device between said first and second power sources.

Thus it will be seen that in accordance with the invention a user may choose either of the two power sources to operate the device. This has the advantage that where one of the power sources becomes unusable, the user may simply select the other one, thereby enabling him or her to continue to operate the equipment. Providing a manually switchable power source obviates the complication and expense arising from providing electronic circuitry to perform this function, e. g. by monitoring the output voltage of the power source. Furthermore, it gives the user a positive indication that one power source has become exhausted, so that it may be replaced.

Preferably both power sources are the same and most preferably they both comprise one or more batteries. In accordance with such embodiments, one battery or set of batteries may be used to operate the equipment until the batteries run out whereupon the user may then simply switch to the second battery or set of batteries to continue powering the device. Thus the inconvenience of the batteries running when the user has no access to obtain a fresh set is avoided since, in effect, the user is encouraged to carry a spare set of batteries with them and moreover they can be conveniently stored within the device itself. In other embodiments however, the power sources may be different.

Most preferably, the power sources have the same power and/or voltage rating.

The invention may be beneficial in any portable electronic device, but is of particular benefit when used with personal hi-fi equipment such as personal cassette recorders, compact disc player, mini-disc players and the like since it has been observed that users of such devices tend to find running out of power the most frustrating because such use tends to be on a continuous basis for relatively long periods of time.

Moreover the current drain of such devices is relatively high since they almost invariably incorporate some sort of electric motor.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying figure which is a schematic diagram showing the electrical layout of the power sources for the device.

In the preferred embodiment the portable electronic device is a personal stereo cassette player, although, of course the invention is equally applicable to any portable electrical device.

The cassette player 1 comprises a first power source 2 in the form of a battery and a second power source 4 in the form of a second battery. Either battery has sufficient power to power the cassette player mechanism and control 6 individually. As will be seen, the positive terminals 8,10 of the two batteries are connected together electrically and are in turn connected to one side of the electrical input 12 to the cassette player proper 6.

The other electrical terminal 14 of the cassette player is connected to the common terminal of a single changeover switch 16. The two switched terminals of switch 16 are respectively electrically connected to the negative terminals 18,20 of the batteries 2 and 4 respectively.

In the condition shown, the device 1 is being powered by the first battery 2. However, when that battery runs out, which may happen abruptly and without warning, the user may simply operate the switch 16 so as to move it from the position shown to the opposite position in which the negative terminal 18 of battery 4 is electrically connected to the terminal 14 of the cassette player 6. The cassette player 6 may then continue to operate using the second battery 4.

It is then possible for the user to replace the first battery 2 at his or her leisure at any time during the lifetime of the second battery 4 to ensure continued operation.

It will be apparent to those skilled in the art that many modifications and variations may be made within the scope of the present invention. For example, either of the batteries 2 or 4 may be replaced by another equivalent power source for example one which is permanently installed in the equipment such as a solar panel. Furthermore, the equipment need not be a cassette player but may be any other portable electrical device, such as a radio, CD player, personal organiser and so on.

Claims

Claims 1. A portable electrical device comprising a first power source and a second power source, said first and second sources providing sufficient power individually to operate the device and manually operable switching means for switching the electrical input to the device between said first and second power sources.
2. A device as claimed in claim 1, wherein the first and second power sources are the same.
3. A device as claimed in claim 2, wherein both of said power sources comprise one or more batteries.
4. A device as claimed in claim 1,2 or 3 being a personal hi-fi device.
5. A portable electrical device substantially as hereinbefore described with reference to the accompanying Figure.