Abstract A battery-powered, self-propelled electric wheelchair includes unique control circuitry. Thrust is provided to propel the wheelchair by a chain drive assembly linked to a permanent magnet, low RPM motor, thereby avoiding the necessity of complex and inefficient reducing gears. The controlling circuit maintains a high degree of electric efficiency by supplying the motor with a pulse width modulated voltage supply throughout most of its useable speed range. When higher speeds are desired, or where the work potential must otherwise be maximized, an automatic bypass relay couples the battery directly to the motor thereby bypassing the control circuitry and avoiding transistor power losses. The control system incorporates a lock out switch which prevents the operator from changing the direction of travel when voltage is supplied to the drive motor, thereby preventing ''''jackrabbit starts'''' or possible tipping of the unit due to excess acceleration. Unit control, steering and braking are accomplished by a single control handle that also supports a lever for actuating drum brakes. A built-in battery charger features an automatic charge rate control and a battery condition indicator light.
An electrically powered motor-driven wheelchair, said wheelchair comprising: a battery for the production of DC power; a motor; motor control means operably connected to said battery for generating a plurality of DC pulses, the pulses being applied to said motor to energize same; means for reversing the electrical connection of said motor to said control means to thereby reverse the direction of travel of said wheelchair; means for bypassing said motor control means, said bypassing means permitting operation of said motor under preselected low voltage battery conditions; and bypass defeat means for preventing the engagement of said bypass means whenever said motor connection reversing means is engaged, said bypass defeat means thereby preventing said motor control means from being bypassed when said wheelchair is operating in reverse.
Claim 2
Dependent Claim
127 words
An electrically powered motor-driven wheelchair, said wheelchair comprising: a battery for the production of DC power; a motor; motor control means operably connected to said battery for generating a plurality of DC pulses, the pulses being applied to said motor to energize same; means for reversing the electrical connection of said motor to said control means to thereby reverse the direction of travel of said wheelchair; means for bypassing said motor control means, said bypassing means permitting operation of said motor under preselected low voltage battery conditions; and bypass defeat means for preventing the engagement of said bypass means whenever said motor connection reversing means is engaged, said bypass defeat means thereby preventing said motor control means from being bypassed when said wheelchair is operating in reverse.
Claim 3
Dependent Claim
27 words
The combination as in claim 1 including a reverse mode defeat means for preventing the engagement of said motor connection reversing means whenever said motor is energized.
Claim 4
Dependent Claim
27 words
The combination as in claim 1 including a reverse mode defeat means for preventing the engagement of said motor connection reversing means whenever said motor is energized.
Claim 5
Dependent Claim
20 words
The combination as in claim 1 wherein said motor control means includes means to vary the width of said pulses.
Claim 6
Dependent Claim
20 words
The combination as in claim 2 wherein said motor control means includes means to vary the width of said pulses.
Claim 7
Dependent Claim
20 words
The combination as in claim 3 wherein said motor control means includes means to vary the width of said pulses.