[RobRoy]

>>You mean a method for using a variable rotary potentiometer to adjust amplitude of sound output?<<

Yes, but although different volume knobs work in different ways, the way the human interacts with it is the same. Some volume knobs click at each step and use a completely different signal path for each “click” of the knob. It’s like a steering wheel on a car. You can have rack and pinion, recirculating ball, or even “drive by wire”, all patentable, but the driver is just using the same ol’ steering wheel.

[ReignOfError]

Yes, but although different volume knobs work in different ways, the way the human interacts with it is the same. Some volume knobs click at each step and use a completely different signal path for each “click” of the knob. It’s like a steering wheel on a car. You can have rack and pinion, recirculating ball, or even “drive by wire”, all patentable, but the driver is just using the same ol’ steering wheel.

Google patent search turns up 20,000 patents for "steering wheel" between 1880 and 1920 alone.

[Swordmaker]

driver is just using the same ol’ steering wheel.

And the steering wheel was patented also... and licensed for use to the other makers while that patent was in effect. The steering tiller, however, was not because of the prior art from ships, wagons, and other uses.

[Swordmaker]

driver is just using the same ol’ steering wheel.

And the steering wheel was patented also... and licensed for use to the other makers while that patent was in effect. The steering tiller, however, was not because of the prior art from ships, wagons, and other uses.