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Thread: Looking for automated blast gate options

  1. #16
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    Quote Originally Posted by Alan Schaffter View Post

    I think a retail autogate system that is cheaper than Eco-gate is possible, but it is amazing when you get down to every little component, assembly, etc, the costs climb quickly. I think it could be done using a small DC motor and leadscrew. Pneumatics would be too expensive. Though start-up costs for tooling, PCBs, molds, etc. might run in the high tens of thousands or more, I think production (and retail cost) could be kept down if it was manufactured off-shore. I wonder what the auto industry pays for the small motors used on door locks?
    When I contemplated the solenoid lever style design, I picked up a generic auto door lock actuator from All Electronics corp for $6. It only has a 3/4" throw. I wonder how it works internally. Based on the look and feel, I don't think this one is a lead screw design but a spur-and-spool gear combination.

  2. #17
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    After seeing the EcoGate gear driven design, I was wondering if instead of a pivoting gate, a linear gate that was gear driven would be feasible? One design that is popping into my head, is drilling a series of small properly spaced holes down one edge of the gate. The motor would be mount just near the top of the hose connection (in the same area as Dan's design, only turned 90 degrees).

  3. #18
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    In a non-production design, I think a leadscrew and follower arrangement like Dan used, would be easier to build.

    A damper gate would take less space, but then you must come up with an easy way to make the flapper seat and deal with dust possibly collecting on the damper.

    Of course, then there is the iris gate. It must be easy to make because you see them in all the sci-fy space movies.

  4. #19
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    hmm, you joke about the iris, but thinking about it, it would actually solve several design needs: it would be a small gate as the closing leaves are just a fraction of the diameter of the opening, and a short solenoid or motor throw would activate them, as they operate via a small levered movement. Could be attached to a ring that just had to move 3/4" or so to open or close them. Every old camera in the world had them, so we know they're not too bulky or expensive. If you made the leaves thick, they should withstand the vacuum.

    This actually seems like a pretty good idea, someone fiendishly clever and handy like Alan should actually take a poke at building one!
    Thread on "How do I pickup/move XXX Saw?" http://www.sawmillcreek.org/showthread.php?p=597898

    Compilation of "Which Band Saw to buy?" threads http://www.sawmillcreek.org/showthre...028#post692028

  5. #20
    I think the problem with the iris is that it'd never be fully closed (I've never seen one that goes all the way shut - have you?). Also, to get anywhere close to fully closed, you'd need a ridiculous number of leaves for a 6" dia gate.

  6. #21
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    My little girl has a toy with an iris on it. I see how the open close mechanism works. But it is design to never be fully closed (it has a heart shaped opening at the center...it is a girl's toy). In short, each leaves has a fixed pivot point, just inside a rotating ring. The ring also has a point that attaches to each leaf which provides the "lever" action to open/close the leaves. The number of leaves used affectes the size of the leaf and therefore the extra space outside the pipe diameter. More leaves=less increased pipe diameter.

    I'm definately not fond of the damper design. Easy enough to make and automate. I run a lot of pine. I would be very fearful of clogs from the planer and the jointer. I woulda almost gaurantee that it would clog.

  7. #22
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    Quote Originally Posted by Anthony Whitesell View Post
    I'm definately not fond of the damper design. Easy enough to make and automate. I run a lot of pine. I would be very fearful of clogs from the planer and the jointer. I woulda almost gaurantee that it would clog.
    Over the course of 20+ years, I have run just about every common species of wood thru my planer and jointer using the damper design. No issues. If the system clogs, there's something wrong with the duct design, or perhaps the dust collector is underpowered.

    If I was to set up shop again, I would consider a neat design that was posted here about two years ago. It was a sliding blast gate that pivoted at one end and had two pull ropes at the other end: one to open, and one to close. No motors, no air cylinders, just a simple tug. It was meant to be installed in the overhead. A simple 24V relay and microswitch can be rigged to the gate to auto start the dust collector. Very simple, low cost, and very elogant.

    Jeff
    Thank goodness for SMC and wood dough.

  8. #23
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  9. #24
    I was reading over this thread very late last night on my phone and wondered, if the OP is wanting to operate the gate without having to climb behind the machine (squeeze back there) why not simply run a cable operator to the front of every machine that you simply open and close manually? I know this isnt as cool as an auto-open feature but I seem to recall seeing a tip in an FHB reader contribution where a guy simply used lawnmower choke/throttle cables to run a pull handle right at the on/off switch of each tool. This way he just opens and closes each gate when he starts the tool leaving the DC running continuously.

    I know there was tool triggered auto-open talked about but I think it was mentioned you wouldnt want the DC kicking on and off every time you pulled the trigger on a tool or flipped the switch.

    Sorry if this has been covered....

    Mark
    Last edited by Mark Bolton; 11-28-2010 at 12:52 PM. Reason: typo

  10. #25
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    Quote Originally Posted by Josh Bowman View Post
    Good job on the search. That's the one.

    I like the funky art deco shape. However, I think it could be made a little more compact.

    -Jeff
    Thank goodness for SMC and wood dough.

  11. Hey Dan,
    I was wondering if you ever did put together a post about the blast gates. As a disabled person, I find that the design would really make my life much easier!
    Quote Originally Posted by Dan Friedrichs View Post

    In the next few months, once I finalize the control boxes, I plan to do a large post here at SMC explaining all the details and including all drawings, schematics, parts lists, etc.
    I am thinking of a few mods that may make the unit more compact, and possibly cheaper.
    maybe under $30 for a 4" (need to test before I go shooting off my mouth!)

    Thanks!
    Bruce

  12. Quote Originally Posted by Dan Friedrichs View Post

    So I went with a lead screw and reversible DC motor. I configured mine with a simple arrangement of 2 limit switches and 2 diodes, such that it closes when +12VDC is applied, and opens when -12VDC is applied. This way, I can run only 2 wires to each gate, and by flipping the polarity of the voltage on that wire, I can open or close it. Also, I don't need to feed back position information or anything else - once the gate hits the limit switch, it becomes an open circuit until the polarity of the voltage is reversed.
    where did you get the lead screws and the connector to mate it to the motor?

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