OTish: What kind of clamp to quickly seal the mouth of a sack vs a chute?

Hey all, I'm having trouble figuring out the name of what I'm after. I need to make a clamp that will quickly seal a sack (like 50# feed sack) against a round chute, probably 8" dia or so. I'd like something easy and quick to operate with one hand. It doesn't have to have incredible or totally air-tight clamping or anything.

For the drinking water filter factory I'm helping set up over here, I'm modifying a hammer mill (yard chipper/shredder) so that the output can be captured in a sack rather than fall onto the ground. The factory uses it to mill unfired clay brick chunks into clay powder, and having that fall onto the ground like the wood chips would in the normal application of this machine is making a huge mess, not to mention ruining the gas engine that runs it. So, I'm scrapping it's factory wheeled platform and making a new one to bolt to the factory floor, but moving the milling chamber up off of the ground to make room for a sack standing up to be underneath it. Hence, the operator will pull the empty sack under the machine, use this clamp to clamp the open mouth of the sack against the chute I'm going to make to channel the output, and start milling. Once the sack is full, undo the clamp, pull the sack out of the way, put an empty one in, clamp, and repeat.

I was thinking about something like a bicycle seat clamp. That seems unnecessarily precise since my only milling capabilities are manual (until my Tree J425 gets here in a few months!), so then I thought about the kind of rings that seal the top on a barrel. I think I've seen some that have an adjusting screw that you'd set once for your diameter, and then kind of a flip over lever to lock them in place. The weight of the sack will be sitting on the ground, so it doesn't have to hold the whole weight of the contents, just keep the lip against the chute so the output doesn't get in the air. What's such a clamp called? I searched for toggle clamps, but that only brings up the "pin down your workpiece" kind.

I can't imagine this will be hard to knock out (only need one plus a backup) but I don't have a clear enough picture in my mind to go and make it, so I wanted to find a couple of pics on google, but can't figure out what to search for.

Thanks!

I found "drum locking ring", but those don't seem to have much or any diametrical adjustability.

Maybe I just need to make a ring slightly smaller than my chute, make the locking ring to form around that, and that will "stretch" it when it's closed over my slightly bigger chute? I figured adjustable was nice because if the slip roll misses by a little while making it, I can still take up the slack, but maybe I should just make it better so that's not necessary.

Can you make a dump bin that will go where you want to put the sack? The bin would hold 1 sack full and the operator would just hold the sack to the bins chute and tip it to fill, never letting go of the bag. When in tipped position the bag could even sit on a low table to ease operator fatigue. All operator would do id hold bag on the chute and remove heavy bag when full. For faster production it could be "double acting" bin that is two back to back, so when one is dumping the other is filling, changing sides to fill bags.

Rob F. said:

Can you make a dump bin that will go where you want to put the sack? The bin would hold 1 sack full and the operator would just hold the sack to the bins chute and tip it to fill, never letting go of the bag.

Click to expand...

Could, but this clay is a really fine powder, and any dumping will get it all over. (Ever try to dump a 5# thing of flour out?)

What advantage do you see in doing it in 2 steps instead of my 1?

I added a little to first post.
I see it as faster for the operator to not to mess around with clamps.
I guess you could put a table under the bag and just bungee the bag to the output. What happens when they overfill the bag?

JasonPAtkins said:

Could, but this clay is a really fine powder, and any dumping will get it all over. (Ever try to dump a 5# thing of flour out?)

Click to expand...

My family has had a brick making factory they set up around 1870 and ran until about 30 yrs ago. Now it is just sitting, yes I am familiar with clay, and its dust.

I see a pneumatic clamping system that can be operated with a foot switch. Perhaps a draw band?

Tom

JasonPAtkins said:

Could, but this clay is a really fine powder, and any dumping will get it all over. (Ever try to dump a 5# thing of flour out?)

What advantage do you see in doing it in 2 steps instead of my 1?

Click to expand...

I want to fill the bin, and spend 3 seconds dumping in into the bag. It sounds like you want to clamp the bag to the machine where I want the dump bin. Then feed the machine to fill the bag?

I suppose you can easily get a strip of thin sheet metal, perhaps from a large hose clamp, or sheared off a big sheet. Once the length to go around the bag and chute is figured, braze or bolt the ends of the strip to the jaws of a Vise-Grip style pliers. Vise-Grip made a chain wrench, but the chain would be difficult to manipulate over the bag end. There are some automobile oil filter wrenches that could provide a design to copy.

Larry

Even better: The dump bin has the bag attached with your clamp on its output chute as the bin is filling. The bin is on a spring loaded table so when it reaches the proper weight it dumps. This way they just feed the grinder until the bin kicks out, remove full bag, instal an empty bag and reset the bin.

Ok, here is one idea. Let's see how it gets destroyed! ;-)

Rather than clamping around the bag, clamp inside the bag with compressed air.

Say you have a round chute with an 8" outside diameter for example, and say your bag opening has 10" diameter. Imagine a small rubber tire inner tube wrapped on the outside of the chute but deflated and perhaps even the vacuum pulled out so as to stay close to the chute wall.

Slip the bag around chute and inner tube, press a pedal, the inner tube fills up instantly to a fixed PSI and seals the space between chute and bag.

Fill the bag, press another pedal, the air from the tube gets released, or ideally sucked out, and the bag is removed and replaced.

Rinse and repeat.


Jacques

How about a rubber adjustable pipe clamp (like you'd use for removing an oil filter).

Could replace the original rubber with a strip as long as you need. Secured with vice grips (like LVance's suggestion). Or use the same plastic cam holder/handle as the original...with a bungee cord attached to the end to keep a little pressure on it when the bag's in place.

I think you want one of these: DE-STA-CO 351-R Pull Action Latch Clamp: Toggle Clamps: Amazon.com: Industrial & Scientific

Rivet or screw to a flat piece of spring steel, formed piece of flat bar, or split section of a tube.

There are variations on the above, search "locking latch clamp"

Eric

*edit* even better ---- https://vactruckstore.com/product/8-ring-lock-clamp/

Even simpler...a large rubber band or inner tube or bungee. Stored slid up the tube until you're ready to use it. Place the mouth of the bag over the chute and roll the rubber band down over the mouth of the sack.

As long as the bottom of the sack is resting on something the right height, no significant downward pressure on the band. Just holding it in place.

Dumpster_diving said:

Even simpler...a large rubber band or inner tube or bungee. Stored slid up the tube until you're ready to use it. Place the mouth of the bag over the chute and roll the rubber band down over the mouth of the sack.

As long as the bottom of the sack is resting on something the right height, no significant downward pressure on the band. Just holding it in place.

Click to expand...

This would work really well if you had some kind of groove or flange near the end of the chute. Something to help the stretch clamp hold on to the bag.

if I knew how to quickly seal the mouth of a sack, I might still be..., oh, never mind.

What about a zip tie, except the big ones they make for a/c ducts?

pro-tec makes what you are asking for, a stainless band with a toggle latch. many sizes are available some adjustable. McMaster I believe has them, Protec sells on line. If the bag is supported and the band is not supporting much load, than aa silicone rubber band or any big rubber band will work. Graffiti Joes on amazon has these.
or a 4 segments of ridged toggle clamps that fold down. Cement bags and similar use a clever arrangement called a valve top bag. the filler is a horizontal tube and the top of the bag has a slot and a baffle, the bag hangs off the filler tube and when it is full it either is manually pulled off or a weighing mechanism dumps it off. the weight of the contents closes the baffle and thus seals the bag. pretty common once you look for it.

What about a chute that is tapered bigger as you raise the bag up over the chute. This would accommodate different sized bags and no moving parts.

JH

Probably a band clamp with an over-center toggle. This is the same kind of quick release clamp that hold fire extinguishers onto the mounting brackets. I've seen similar for 4 inch dust collection hoses and as I recall that's how water bottles use to mount to bicycles..

Probably your best bet would be to steal the clamp mechanism from something like that and rivet it onto a piece of steel shipping band. Maybe slip some soft tubing over the band first to protect the sack.

A big "tie wrap" or "zip tie"?
Cheap to buy, easy to install and remove