There are ideas that already handle this suction problem but some are complicated and messy, and all would require additional steps in the manufacturing process. I mention simple because it doesn't require an additional manufacturing step, but is a simple redesign that performs the function of pressure equalizing.
Invision this: A trashcan with 1 inch deep groove slots in the side of the trash can. It allows air to pass by not allowing the trash liner to suck up to the full inside edge of the trash container.
Please take a look at the illustrations in the links.-- twitch, May 23 2007 Illustration of Trashcan http://img254.image...ovedtrashcanrj8.jpgeasy with a pic, hard with words. [twitch, May 23 2007] Version 2 http://img87.images...95/trashcan2zn6.jpgThis should solve suck and stack problems [twitch, May 23 2007] Upload your pictures to a free file server and link them here.-- nuclear hobo, May 23 2007 I've had similar thoughts, though I would use an interior pipe that runs from top to bottom. Punching holes in the bag or the can could be bad if it's necessary to dispose of any liquid waste.-- supercat, May 23 2007 You guys are over complicating it. All you need is a hole or two in the garbage can, near the bottom. And liquid waste wouldn't be a problem as long as you have a durable enough bag without any holes.-- BJS, May 23 2007 one cannot ensure a durable enough bag. It's not only that getting a more durable bag is more expensive, it's also that making holes in your trashcan can lead to a big mess.
[supercat], i think i read your idea or somebody's idea like yours, but i am also focusing on the manufacturing benefits of this idea.
Please see the illustration I have linked.-- twitch, May 23 2007 Okay, so you're adding some ribs. I can certainly see how that could work, though the ribs could cause difficulty if an object inside the trash happened to wedge itself between them. Further, the ribs as drawn would prevent the trash cans from stacking for transport.
The best bet would probably be to construct the can as two pieces--one piece that's pretty much ordinary, along with a "pipe" insert. The only special feature of the first piece would be a couple of notches to allow the pipe to be secured in place.-- supercat, May 23 2007 //simple redesign that performs the function of pressure equalizing// Are you ribbing me?-- phundug, May 23 2007 Won't pipes and notches also alter stacking ability? Also, won't it create another manufacturing process, or an assembly process for consumers?-- twitch, May 23 2007 While these wouldn't nest as well as a smooth-sided conventional can, they could still stack to some degree. It would conceptually be the same as stacking containers with thick walls. The degree of nesting would be dependent on the draft angle of the side walls.
If the ribs could be redesigned slightly to be broader at the base and molded through to form hollows on the outside, some portion of the interior convex ribs could fit in to the corresponding concavity formed on the outside of the can, thus improving the nesting to some extent.-- half, May 23 2007 haha.. [half], that was my next redesign. working on it right now.-- twitch, May 23 2007 V.2 might work for garbage bags but it will be difficult to get nested cans apart.-- nuclear hobo, May 23 2007 I don't know for sure. I had the same initial reaction, though. Here's what I came up with after thinking about it for a minute:
The surface area in contact between nested conventional cans is pretty large and they come apart...eventually. If the angle of the ribs inside the can is more acute than the hollows into which they fit, only the tip of the rib will contact the can in which it nests thus preventing it from wedging tightly.
I think a lot would have to do with the flexibility and "soapiness" of the plastic.-- half, May 23 2007 But the vacuum problem remains no matter how slippery they are. In the ribbed can the surface area has been increased, increasing friction as well.-- nuclear hobo, May 24 2007 With the ribs making only point contact when nested, I'd contend that the surface area in contact might actually be reduced. Additionally, the arrangement I described would actually create small channels for air to pass.
A smooth, continuous outer surface in contact with a smooth continuous inner surface of nesting cans seems more likely to create a seal that would support a vacuum that would make it difficult to pull the nested cans apart. The ribs could actually break that more or less continous seal by preventing a tight fit in the channels as I described previously.
For the same reason that the ribs were proposed originally, they could help remove one can from inside another.
Some existing cans are fairly difficult to pull apart and they seem to sell fairly well. I don't know that a defect that impacts the user only one time just prior to the purchase would overwhelm any improvement in the lifetime functionality.-- half, May 24 2007 Actually, what I was describing doesn't really show as clearly in the second illustration to the extent that I'd imagined it.
One way to explain it might be to leave the contour of the concave portion as it is, but bring the convex (inside) part to a point.-- half, May 24 2007 The vacuum problem is not a friction problem. Plastic is very slippery. Friction between trashcan and trash bag is not too much of a factor unless of course, you normally stuff your trash can with 2 X capacity.-- twitch, May 24 2007 "The vacuum problem is not a friction problem."
Not sure who that's directed toward. I didn't say that was a problem. I wasn't talking about the liner at all. Rather, I was addressing the side issues of stackability and (obliquely) additional manufacturing processes.
Maybe I misunderstood the hobo's objections.-- half, May 24 2007 Having worked at jobs where I experienced both the unstacking and the unbagging vacuum problems I can only relate what we did back then to try to achieve separation.
In the case of a stack of nesting containers, we'd lay the stack on its side with a pair of employees grabbing opposite ends and pulling for all we were worth, flexing and shaking the stack as we pulled. If the design of the container allowed, we would insert a small wooden dowel (a yardstick also worked well) down between the sides to encourage air flow. Some manufacturers understood the dilemma and tried wrapping the cans with tissue paper to prevent the vacuum but that rarely worked. The best preventative measure I recall was when the factory put in a couple of strips of corrugated cardboard inserted vertically between the cans.
As for the exit vacuum, well emptying the cans was already a dirty job so we'd basically have to "burp" the bag before extricating it. First thing was to tie off the top of the bag to prevent leakage. Next, you'd slide your hand down between the bag and the side of the can to break any air pocket, then you'd lift the bag out, hoping like heck it didn't leak because you were usually either clenching the can with your knees or you had the can's base wedged between your feet (just ahead of the instep works best).
So I can say from experience this idea appears to have a good chance of solving the extrication dilemma, but I'm not convinced the grooves will prevent the cans from getting wedged together. I have seen how shippers handle the cartons these things come in. They get dropped and slammed a lot, which only wedges the contents together tighter, making friction a real problem, no matter how slippery the plastic. Now if you were to add "feet" to the design I'd say you were making progress. Make the feet the right length and there'd be no way for the cans to become jammed together and your fancy-schmancy ribs will be much more effective. (Or simply get the manufacturers to put a chunk of cardboard bent in a V to provide separation so the cans don't get compressed into each other - which would be cheaper, a disposable cardboard spacer or the extra plastic needed to make molded feet?)
The voice of experience has spoken! (Pay no attention to that man behind the curtain!)-- Canuck, May 24 2007 Being one not used to painting a bright picture with words alone (I often need an actual picture), I finally get what half and canuck are saying. Something clicked. The light just went on. Or however you put that moment of discovery or understanding. I think I already solved that problem with a design that I implemented in my second illustration but failed to mention in any annotation or description:
At the bottom portion of the trash can is a depression in the trashcan. The reason it is here is for you to put your foot into it so you can pry trash liners more easily from the trash can. I didn't know that it could be a design element that would aid in pulling trash cans apart but this is what it does as well. It limits how far each trash can can fit into eachother. Although now you don't have a really tight fitting trash can, and that means you use my space for shipping, it means you have an easier time taking trash liners out as well as removing trash cans from their stacks.-- twitch, May 24 2007 I saw that recess, but wasn't sure if what I saw was what I thought it was. I think that could do the trick. But, I also think it complicates the mold and the release of the finished product from the mold. (In case you were serious about building this. I'm not an expert, though.)-- half, May 24 2007 //In the case of a stack of nesting containers//
Take a hose and spray the lip of the bottom can while the cans are standing upright. The water will find it's way in and make them seperate. This works even better if you have a thin sweeper nozzle that you can jam between the cans. I think what actually happens is that the top can floats out.
I've done this about a thousand times with those square garbage cans that they use in bars and restarants, but it works on any plastic container.
If you can get even a little water in there you'll never tug another can.-- nomocrow, May 24 2007 It pains me to say that that is perhaps the most useful thing I have learned on this site.-- MaxwellBuchanan, May 24 2007 Here's a bonus air-pressure-equalising tip, this one for impossible-to-open jars: slide the tip of a knife under the lip of the lid, and turn the knife, to pop the seal and make the jar easy to open.-- imaginality, May 24 2007 Thank you, Heloise. I mean imaginality!
Here's another helpful hint: use a potato when you need to remove a broken light bulb from a socket. First, make sure you shut off the power to the light. Next, cut off a chunk of raw potato and use it as a handle to safely unscrew the base from the light socket. However, do not attempt to eat that portion of the potato. You must throw it away with the broken light bulb.
I know this has absolutely nothing to do with the idea here. I just wanted to share.-- Canuck, May 25 2007 Potato? I know it has been mentioned as a safe way to remove a broken light bulb but a dangerous concept exists: pushing towards broken glass. It is a bad idea. What if the potato slips! you will have thrust your hand into shards of glass. What if your potato is too strong, or the glass too weak! you could break off a chunk, and still thrusting that hand forward, thrust it into another shard of glass, not to mention that now you have a improvised potato-knife (a potato with a shard of glass stuck in it).
Hey, what's this anno doing here anyhow?-- twitch, May 25 2007 Oh! Are we giving useful hints now? Put ten pounds of rocks in the bottom of the trashcan and the bag will be much easier to lift out.-- Galbinus_Caeli, May 25 2007 random, halfbakery