It has been a while. Maybe a little off topic for a Supercell titled blog but sort of the next step in improving dust collection in my shop. The best value I could find on a 2.5" long-ish shopvac hose was a 20' Ridgid hose. It was about 1/3 what the 25' Onieda hose goes for. With the longer hose I definitely need a good way to get it out of the way when not in use. I was going to design and make a reel from plywood on my CNC but I realized that after buying all of the plywood and hardware needed, I was not saving that much money compared to just buying the Fastcap Super Reel so that is what I did. It is made from Baltic birch PW and includes everything needed for assembly but a 2x4. By increasing the length of the 2x4 sections, you can increase how much hose it will hold -- 3" per 10' of hose. As you may recall from the discussion in the previous part in this blog, because wall and floor space is at such a premium, I was thinking about ways to put a hose reel for the shopvac hose on the ceiling and figuring out a way to operate it from the ground. One idea I was thinking about for operating from the ground was making a rope chain fall (you can see a concept in the discussion of the previous part).
I have recently been noodling about using a spring retraction mechanism similar to those used in air hoses. While looking for a spring mechanism, I watched a few YT videos that show how to repair air hose retraction springs and I caught a gimps of the locking mechanisms in a couple of them so I am in the process of designing a mechanism that will allow you to feed out hose, lock it, and with a slight tug release the lock and have a spring rewind the hose. Below is my conceptual design of the locking mechanism.
Mine is a little different than those that I saw in the videos but essentially the same idea. The pockets before and after the locking teeth on the sprocket allow the pawl to pivot directions to switch from free mode to locking mode and vise versa by simply reversing the direction once the pawl has fallen into the pocket. If you rotate the above wheel clockwise from a locked position, the pawl will fall into the pocket and the wheel will turn freely when you reverse the direction to counter clockwise (theoretically letting the spring rewind the hose). Likewise when in free turn mode, if you reverse the direction back to clockwise after the pawl falls into a pocket, it will pivot back to locking mode. That is the theory anyway. This was drawn in Onshape but unfortunately its animation capabilities (or my Onshape skills) are not up to doing a full simulation (at least with a free subscription anyway) but I can sort of simulate it manually by turning the sprocket a little at a time and moving the pawl as I expect it to move. I think that it just may work. I am planning to make a prototype so that I can test it by mounting it on a board to see what adjustments I may need. I will report back once I play around with it a bit. What do you think? Will it work?
If it does, the next step will be to find a suitable spring. First place I looked was at replacement springs for air hose reels but most of them are pretty pricey -- $50 and up. I did buy a cheap spring on Amazon just so I can test the concept (I think it is for a small engine starter rope recoil) but suspect it cannot make enough turns to handle the full 20' of hose. I think that each 10 feet of hose will require an average of 3 turns. I have found one constant force spring on eBay that is about 5000mm long that may fit the bill that is under $25 so if my proof of concept works, I may order that one.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
Your picture shows a small spring above the pivot point of the locking pawl. If the bottom part of the pawl is heavy enough to fall in position by gravity, I don't think the little spring is necessary. I think your idea will work. I have never seen inside a hose reel mechanism, but I imagine it is basically the same idea.
"Duck and Bob would be out doin some farming with funny hats on." chrisstef
I think it’ll come down to the tension holding the pawl in orientation and the exact length and spacing relationship between the pawl and the gear teeth on the locking wheel. Don’t see why it won’t work. 👍🏼
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
I've though about this same thing before (garden hose reel). Almost bought a HF hose reel just so I could whack off the side flanges for the same style of mechanism.
Duck, I assumed that gravity would be all it takes to make the pawl rotate into position but with a spring, I can position it anywhere around the sprocket and it will still work. If I rely just on gravity friction could prevent it from falling into place, especially as it wears or collects dust and dirt over time.
Ryan, the spring on the pawl is just to make sure that friction or orientation do not prevent the pawl from staying in contact with the sprocket. It really isn't necessary for the pawl to lock in place, that is, as long as I make the latching pocket or "tooth" shaped correctly and the pawl pivots freely. If you look more closely, you can see that when it is in the locked position below, what keeps the rewind spring from turning the reel and sprocket clockwise is that the "tooth" tries to pivot the pawl, which pushes it down into the sprocket, causing it to bind. Basically the sprocket is in the way of the pawl turning. I should have shown these closeups before. Note that the arrows in the drawings below just indicate that I used a revolve connector in the assembly in Onshape. Those pivot points can turn in either directions. Also note that the 2 small circles on either side of the dark blue axle are key ways for locking the sprocket to the central shaft which is screwed to the side of the reel. They should stay aligned as the sprocket/axle turn. I just haven't locked them together properly for a good animation.
Locked Position:
Pulling the hose to turn the reel and sprocket counter clockwise to this point and reversing to clockwise, will pivot the pawl to the free turning rewind position. If you reverse back to counter clockwise at this point (below), the pawl will move back into locking position so that it can lock when you pull the hose enough to engage the next locking tooth to the left. As you pull hose off the reel, the pawl will naturally pivot to the locking position so that when you release and the rewind spring pulls it clockwise, it should stop as in the first locked position above.
All in theory anyway. I think that spring should make the pawl click like a rachet as it falls into the pockets That should provide an audible clue when to reverse direction or let the rewind spring take over.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
A buddy of mine (Mech engineer) had a book called "Ingenious Mechanisms" which was chock-full of goodies like this. Some really creative minds figure out these contraptions.
years ago I used to sell old books on ebay. Had a friend at the local library and they would call me in when someone dropped off a load of books from an estate.
Sold a complete collection of "Home Shop Machinist" which went very quickly. Lots of old airplane mags and engineering books. Many even went to people in Europe.
Well that went well. I cut out a sprocket and pawl with my CNC and slapped together a prototype with the spring I have on hand to test it and it works!
For the test, I just cut a slot in a dowel axle and attached the spring to the back of the temporary mounting board. Here it is as if all of the hose has been fed out. The spring I have will wind 6 revolutions which I think is the minimum required.
The only issue I have with this iteration is that if you reverse direction as if you are going to pivot to the locking position while the pawl is in the locking pocket rather than in a switching pocket, it binds and locks. It may just be friction between the rough surfaces of the sprocket and pawl and I suspect that it could release spontaneously. It could be that sanding it smoother and applying a slippery finish and wax would prevent that but I may have modify to the locking pockets to make the angle a little lower so that it slides more easily back into the switching pocket behind it. Not a big deal.
Anyway, this looks like it is going to work. Now to figure out how best to mount the spring.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
Well, I assembled the reel and added the rewind mechanism. It sort of works but the spring just doesn't have enough oomph to rewind it. I think that the real problem is that they used lazy Susan bearings in a vertical position and they are just not designed to work in that orientation. They not only have a lot of run-out but that also creates extra resistance that the spring cannot overcome. It may work if I sort of push the hose into the reel to help overcome the resistance but it won't work as intended. I ordered another spring but I think that it may not be as strong as the first one.
