Eureka Self-Propelled Upright Vacuums

[eurekaprince]

I just saw a beautiful white Eureka SP upright on eBay - it looks so great in white.

The seller posted a pic of the underside, and it got me thinking: How did Eureka do the self-propelled feature? I see some black thingy on the rear wheels of the unit, but I can't figure out how the main motor would feed propulsion to these wheels. Is there a belt somewhere that I can't see? Or did Eureka put a completely separate motor under the hood just for the wheels? And how did the on-off slider switch for the propulsion feature work? Did the wheels shift into different gears for forward and reverse?

Eurekaprince would love to know all about this magic trick....

 

[powertank]

No, actually Eureka got into some pretty advanced physics. The self propel is driven by magnetics and controlled by telepathy. The handle is there for show. They got to be too expensive to produce, which is why Eureka stopped making them.

No, actually, there is a cogged belt under the hood. The mechanism is similar to Hoover's in that there are two counter-rotating clutches driven by the motor, and the wheels are driven off of the central clutch plate. The handle moves a cable which in turn moves what you'd call a shift fork in automotive terms. The shift fork presses the clutch plate that drives the wheels against one of the two clutches. By doing that, pressure on the handle dictates the direction of the power to the wheels, as well as the torque (seen as speed of the vacuum) that is transmitted. The lock on the handle keeps the central clutch plate from contacting either of the friction discs.

I'm not too good at describing things, so that might not make sense. But in short, Eureka had the smoothest operating self-propulsion system of anyone, and they quit making it.

 

[eurekaprince]

Thanks for that Peter!

Wow - it sounds like you studied engineering!

Would love to see a pic of a Eureka SP vac with the hood removed.....so that I could see the whole mechanism. Interesting that these SP uprights were the only ones with a "down-facing" motor - the cogged belt must have been connected to a gear that shifted the propulsion sideways. Hmmmm.....verrrrry interesting......

EPBrian

 

[electroluxkirby]

I rescued a Eureka self propelled upright from going to the junk yard. I cleaned her up, new bag and belt and she works perfectly. I gave her to a co-worker who is a single mom with two kids, I think she needed it more than I did.

 

[scvacuumguy]

I think we may have one in for repair, it is a nice design for the SP. They are certainly a pain to deal during service. If we do have one in the back, I will take a pic and upload it.

 

[powertank]

Yeah, if I have time, I'll take pictures of mine.

 

[powertank]

Okay, since its been two years since I opened this thing up, I was a little mixed up. It's less similar to the Hoover mechanism than I thought. Everything I said above is basically correct, but the counter-rotating clutch plates are in the center, and the friction plates are on the outside.

 

[powertank]

The Hoover drive has clutch plates that rotate in the same direction. I think the foward direction is directly coupled to one of the clutches, and reverse is coupled through gears in order to change the direction.

 

[powertank]

Under the hood of a self-propelled Eureka:

 

[eurekaprince]

WOW!!!!


Thank you! Thank you! Thank you Peter!

Now I see why the motor hood is higher than the manual versions - they needed some height to add another horizontally-looped belt to drive one of the gears for the propulsion mechanism.

Now one last question - the Hoover SP uprights seem to have motorized front wheels that have ridges that would grip the carpet well. The Eureka SP vacs propel smooth rear wheels. Wonder if these wheels would "slip" on the carpet more than the Hoover's. Any thoughts?

Thanks again for taking the trouble to upload the pics - that was really great of you to do.