cat pump

[drysdam]

Some background.

tldr: I want to make a manually operated, 100% mechanical water pump for my cat who will only drink running water. The goal is about equal parts hilarity and shop-time, with a distant third of making an actual working device to be operated by a cat.

Step 1: A check valve

(The circled dimensions are embodied below, the others are an even-more-prototypical set I made some of last week.)

I need two of these. One pressed into the base of the cylinder (ordinary copper pipe--hints on machining this material, btw?):

and one in a movable piston (bolt is temporary to hold the ball in place and for testing)

Next up is some kind of handle arrangement. I did some math to compute a few angles and distance ratios. I'm not sure if I'll need a cross head or not. I'm going to start without one and see if I can avoid it. My rain barrel water pump doesn't have one, but it may be more forgiving of a cocked piston.

Anyway, I also mocked it up in cardboard to see if I had my math right:

(I'm working on two other projects at the same time, along with normal life, so who knows when the next update will be.)

 

[drysdam]

I thought I could knock off that L bracket in an hour or two this weekend. Boy was I ever wrong. It took me an hour just to hacksaw the basic shape out of 1" thick stock. And it's aluminum! (Maybe I shouldn't admit that.)

Another little while to clean up the saw marks.

Next up is boring the hole for the pipe to poke through. And I realized last night that I didn't think this through too well. My largest drill bit is 1/2" and the pipe 5/8". I don't have a boring head. The piece is an odd shape.

I'm going to try to put it in the lathe and work slow and careful with that long end sticking way out. Otherwise, I may have to rig up a boring bar in the mill.

This progress sounds so paltry and the problem so basic compared to all the other posts here, but I guess everyone has to be a n00b at some point.

 

[kvom]

my cat who will only drink running water

If it gets thirsty enough it will drink from a bowl. :toilet:

 

[drysdam]

If it gets thirsty enough it will drink from a bowl. :toilet:

Maybe so. After a great deal of raucous meowing.

 

[drysdam]

I drag my feet on posting these because it's all so terrible and slow compared to the awesome stuff I see here. But it also keeps me honest and working on it, so anyway.

The bracket that'll hold the pump mechanics to the pipe is done

I also made up the pumping arm and...the rod that comes out of the end of the piston. Is that a con rod or is the next one up the con rod?

I actually debated about how these mechanics were going to work for a while. I eventually DID decide to put a bushing in the top of the pipe to prevent the piston from jamming.

Also, you may notice an incorrectly drilled hole on the pumping arm. I'm going to fix it once I know the correct placement from seeing it.

 

[aarggh]

This is a slippery slope your going down my friend! Next the cat will want an armchair, then probably it's own home theater, and who knows what after that? World domination?

If it were me, and my cat wanted a fancy pump like that, it damn well better learn how to use the lathe and mill itself, although being a cat you can be sure it won't bother to oil the ways when it's finished!

cheers, Ian

 

[aarggh]

If it gets thirsty enough it will drink from a bowl. :toilet:

Ha! There really is an emoticon for everything!

 

[drysdam]

Got all my linkage parts machined

And here's a whole pump.

It even works! Kinda! Now I begin tweaking parts so it works better.

1. Bigger slots in the pipe to let the water out
2. Lengthen the piston rod so the 1" stroke happens farther down (i.e. completely south of the slots)
3. Add the return spring. I think I'm going to need to make my own custom spring here, because I need a combination of long body, low spring quotient and wide diameter.
4. Some kind of legs or something to mount it over a water bowl.
5. Some kind of funnel thing for the cat to lick from.

Not that I'm necessarily going to make this the final product. But I find it a lot easier to iterate an existing design than come up with one from scratch. I'll replace it piecemeal and if I ever get into a dead end, I'll start over with what I've learned up to then.

 

[Paulsv]

Just ran across this, and thought you might be interested.

http://www.woot.com/plus/paw-pet-products-3#

Doesn't meet your requirements (100% mechanical manually operated) and would leave a pool of water on your floor, unless put into some kind of a draining tub.