above: top view of Throne minus the platform and chair.

My favorite chair is of the waiting room type. It is very square and is not
meant to be moved around. This had to be overcome in the most complicated
way possible- by making a motorized rotating base for it to sit on. Even
just spining would add the mobility I wanted with it.

The base was the plastic base from a 70's Zenith console television. It
looks silly and I had it anyways. To allow movement a larger lazy susan
bearing was used. Mounted on this was a smaller peice of wood to provide
vertical clearance from the roller and motor. Bolted on top of this is
a piece of plywood. On this sits the chair of my selection.

The inner race and bottom of the bearing was screwed onto the plastic base.
the outer race and top section was rotated with a rubber roller. In the
pictures this is blue. I had four types to select from. Each color has a
different stiffness. The manufacturer of the roller was Meridian
Laboratories. I got my samples from National Manufacturing Week 1999.

The roller was affixed to the shaft of a Barber-Colman geared motor. I
believe no load speed was around 200RPM with 24v input. A constant source of
tension on the roller was needed for it to keep its grip. The spring loaded
arm pictured was used for this.


above: first useful controls for the Throne motor.

The original logic allowed for the motor to rotate clockwise and
counterclockwise. The turn left and turn right switches are SPDT and cut each
other out when pressed so pressing both does nothing and acts the same as no
buttons pressed. Limit switches could be added to disallow 360 degree motion if
needed. 


above: final Throne control board with brake.

This version incorporates a braking resistor. In the rest state the motor is
shorted out through a relay. However the momentum of a spinning person was
too much and would just make the top portion of the lare bearing slip past
the stalled motor. I added a resistor so the motor would still turn and help
brake the platform. This is the same idea behins ABS brakes. Slipping tires
or rollers do not allow energy to be dissipated by brakes or the motor and
resistor.

Scanned schematics coming soon!

02-24-2000 02-18-2000