Electrical transmission or interconnection systems – Vehicle mounted systems
Reexamination Certificate
1998-03-19
2001-04-24
Paladini, Albert W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
C280S250100, C280S304100, C297SDIG004, C323S282000
Reexamination Certificate
active
06222282
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a personal mobility vehicle such as a wheelchair having a battery powered drive motor. This invention more specifically relates to a personal mobility vehicle having an accessory power system.
BACKGROUND OF THE INVENTION
Personal mobility vehicles (PMVs) such as electric wheelchairs are commonplace but nonetheless invaluable technology for people unable to walk independently. While available configurations vary widely, the electrical system of PMVs can be generally divided into three categories: a drive system (electric motors), a drive control unit, and a power source (batteries).
The drive system includes one or more electric motors. Two motors are often used to provide automated steering. Control units and their user interface vary in sophistication according to the needs of the PMV user, but all serve, in some fashion, to control electric power to the driving unit. For example, PMVs for users with sufficient hand control can employ a joystick drive interface, while PMVs for users without hand control may instead employ a head and mouth actuated system. The commercial standard power source for PMVs is two rechargeable, twelve volt batteries connected in series to create DC electric power at twenty-four volts.
The guiding objective for such assistive technology is to provide independence. To that end, recharging systems have been developed that allow wheelchair users to recharge wheelchair batteries without assistance from others. Also to that end, wheelchair users have come to rely on an ever growing number of other assistive devices now available. Common examples include speech synthesizers and remote environmental controllers. Many such devices work with or through computers adapted for attachment to the wheelchair. Furthermore, wheelchair users, no less than others, enjoy the use of consumer electronic devices such as cellular phones and portable radios, tape and CD players.
To be portable with the wheelchair, these accessory devices must also be powered by batteries. Unfortunately, the required battery type and shape varies according to the electronic device. While rechargeable batteries may be available, they must be separately recharged using an appropriate AC driven power supply. For many wheelchair users, this accessory battery recharging or swapping limits their independence because it requires assistance from others.
What is needed is a PMV that can safely and reliably power the electronic accessories as well as the drive system from the same main power source. Accordingly, the present invention provides a PMV having an accessory power source that draws electric power from the main PMV batteries and delivers stable DC electric power at a given accessory voltage.
SUMMARY OF THE INVENTION
Personal mobility vehicles of the present invention provide electric power to both the drive system and various electric accessories from a common source. Notably, the system of the present invention minimizes disruption in power to the accessories from the characteristic voltage fluctuations at the power source that are caused by activation and use of drive motors.
PMVs according to the present invention include a drive wheel, an electric motor operably coupled to the drive wheel, a main power source operably connected to the motor for supplying power to the motor, a control unit connected between the main power source and the motor for controlling the motor, and an accessory power source adapted to be energized by the main power source. The accessory power source provides at least one accessory power output at an accessory voltage which is independent of fluctuations in the power supplied to the motor.
In a preferred embodiment, the accessory power source includes an input connector for receiving power at a first voltage that fluctuates in response to PMV drive commands, and a DC-DC switching-mode regulator operably connected to the input connector that provides DC electric power at a stable, relatively lower second voltage which is independent of variations in the first voltage. To provide multiple, independently regulated accessory power outputs the power source may include an array of DC-DC converters each operably coupled to the input connector. To support a wide range of different types of electric accessories, the power source may employ at least one DC-DC converter having an adjustable output voltage.
REFERENCES:
patent: 4533986 (1985-08-01), Jones
patent: 5245558 (1993-09-01), Hachey
patent: 5691629 (1997-11-01), Belnap
patent: 5726849 (1998-03-01), Nakamura
patent: 5793189 (1998-08-01), Kawaguchi et al.
Wolfgang & Hutchinson, Eds. “Power Supplies”The ARRL Handbood for Radio-Amateurspp. 6-25 to 6-35, 68th Ed. 1991.
Beechy Dennis
Rossi Robert
Advanced Peripheral Technologies, Ltd.
IP Focus Law Group, Ltd.
Paladini Albert W.
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