3 ms·

See right here is the problem: in hindsight, you think the solution was easy. [Kearns] first patent for the [intermittent wipers] was filed on December 1, 196

by pj 17y ago

See right here is the problem: in hindsight, you think the solution was easy. [Kearns] first patent for the [intermittent wipers] was filed on December 1, 1964. http://en.wikipedia.org/wiki/Robert_Kearns http://en.wikipedia.org/wiki/Robert_Kearns The 555 timer, however, was designed and invented by Hans R. Camenzind ... in 1970 and introduced in 1971 by Signetics http://en.wikipedia.org/wiki/555_timer_IC http://en.wikipedia.org/wiki/555_timer_IC The 555 didn't exist when he invented his wipers. What is your solution now?

CamperBob 17y ago
Sigh. OK, let's work on the 'abstraction' thing a bit. Given almost any mechanical or electrical technology, there exists means of using that technology to control the duty cycles of machines. The 555 was just an example of what you might use to implement an intermittent wiper. As I understand it, accessories like windshield wipers originally operated from manifold vacuum, so the patent probably describes some sort of vacuum-based contraption which would be as obvious to MEs as a timer circuit is to EEs. Another point being, even if it were a novel concept when implemented with vacuum lines and valves, it certainly wouldn't be novel or unexpected when cheap solid-state electronics did arrive on the scene. But chances were good that the patent claims were broad enough to hold sway over future implementations. (Disclaimer: I haven't read it.) So fast-forward your 8-track to the early 70s: windshield wipers are now run from the car's electrical system, and wow, hey, cool, here's the 555... and meanwhile the goofy patent's still in force.
silentOpen 17y ago
Without having read any docs or patents, I'd say some sort of bimetallic strip: two metals, different resistances/heat expansion constants. It's how they used to make turn signal timers.

3 ms·

See right here is the problem: in hindsight, you think the solution was easy. [Kearns] first patent for the [intermittent wipers] was filed on December 1, 196

by pj 17y ago

CamperBob 17y ago
Sigh. OK, let's work on the 'abstraction' thing a bit. Given almost any mechanical or electrical technology, there exists means of using that technology to control the duty cycles of machines. The 555 was just an example of what you might use to implement an intermittent wiper. As I understand it, accessories like windshield wipers originally operated from manifold vacuum, so the patent probably describes some sort of vacuum-based contraption which would be as obvious to MEs as a timer circuit is to EEs. Another point being, even if it were a novel concept when implemented with vacuum lines and valves, it certainly wouldn't be novel or unexpected when cheap solid-state electronics did arrive on the scene. But chances were good that the patent claims were broad enough to hold sway over future implementations. (Disclaimer: I haven't read it.) So fast-forward your 8-track to the early 70s: windshield wipers are now run from the car's electrical system, and wow, hey, cool, here's the 555... and meanwhile the goofy patent's still in force.
silentOpen 17y ago
Without having read any docs or patents, I'd say some sort of bimetallic strip: two metals, different resistances/heat expansion constants. It's how they used to make turn signal timers.