This is another "better design" improvement over the previous Kaczynski mousetrap model and the Goldberg model. None of these designs need welding or power source (other than gravity). The improvements in this model are in the relocation of the shock absorber, and modifications to accept (almost) any wind-up alarm clock, rather than only those w/ external bells. Please note: your design doesn't have to look as tacky as mine unless you're intolerant of details. The frame used here is a scrap 2x4 (but titanium will probably work as well), which can be mounted on the henhouse wall at the best angle to accommodate the location of the door. The layout should be planned so that the cord from the chicken door attaches to the bottom of the 2x2 arm at a little less than 90 degrees. Care should also be taken so the trigger can fall free when the alarm rings. And if you're here from a poultry website link, please check out my main page, I went to a lot of work to make it (IMO).

Mount the shock absorber with the upper pivot located above the hinge, so the shock absorber passes over the hinge as the 2x2 arm swings out. That allows the door to begin moving slowly and speed up as it closes (to give warning to any hens lounging in the doorway), yet completely diminish restraint when the door is closed, so as to give coons minimal space to slide a fingernail under the door. I've never had that happen but it's possible given an unlimited number of coons with nothing else to do for an infinite length of time, the odds are in their favor*. Extra weight (like a pier block) added to the door would help too, the shock absorber should easily handle 15 or 20 lbs, but it would be a strain for people to lift as well. A better plan would be some kind of cam arrangement attached to the door that jams unless raised by the cord. (see lower left corner of the above drawing) The shock absorber should have a nylon loc-nut or several nuts locked together on the upper mounting bolt to prevent the friction of the rubber grommet from turning a single nut after several flex cycles. Said turning could loosen the bolt and alter the restraint on the 2x2 causing it to either freeze up or drop the door, either case resulting potentially in unspeakable carnage. (I bet the CIA is eating this up dudes, so don't carry one of these onto an airplane).

I don't recommend this, but: If you replace the shock absorber with a commercial pneumatic screen door closer, you'll have to remove it's internal spring, because that spring only adds to the weight necessary to close the door, and increases the overall strain on the parts. If you don't remove the spring, you'll have to increase the length of the 2x2 arm (to maybe 5 feet long) to decrease it's leverage. To remove the spring (on pneumatic closers made by Stanley Tools), cut off the end of the tube that the plunger goes into (w/ a hacksaw, being careful not to cut the plunger, or dent the tube) Slide the spring off the end of the plunger. Then bend the cut edges of the end of the tube inwards a little so the plunger piston won't fall out. An advantage of this pneumatic piston gizmo is a little screw valve on the other end of the tube that regulates how fast the piston moves, so you don't have to mess w/ figuring relative door weight vs leverage etc as w/ the shock absorber. The pneumatic closer and the shock absorber have their "restraint direction" configured oppositely, so mount the pneumatic closer to another arm secured to the frame, extending out at 90 deg. in the same direction that the 2x2 moves as the door closes, so the door weight pushes against the plunger instead of pulls as w/ the shock.

View 1 a): Alarm shutoff thingie (w/ rubber bumper from a piece of automotive vacuum tube) is mounted on the Varnax Pivot. b): Trigger alignment guide, keeps bent primary trigger from tipping sideways. A headless nail driven into the 2x4 on either side of the trigger works too. c): Primary trigger, purposely bent so the secondary trigger won't slide up the angle to maximum pressure. d): Screw eye for primary trigger attachment. e): Secondary trigger holds the weight of the door.

View 2 (with & without clock) They're closeups because there's a wall immediately behind the camera. The clock is mounted to the 2x4 this time with a slotted metal clip (b) instead of a bungie, the clock base slides under the clip with a slot for the clock body. The metal used is about 22 gauge equal to that used in oil drums or car chassis, but a bungie & wood frame fusarium to hold the clock seems like a better plan in retrospect because I had to make a brace to press against the front of the clock anyway (flimsy plastic base & I was afraid it would break). $10-$20 Chinese clocks carried by Rite-Aid, Best Buy, Target, Wallmart, etc. are made of crap and only look conventionally sturdy. I've replaced all (5) of the $10 clocks made in China and sold through Rite-Aid, Wallmart, Target, etc, and I'm not happy with them. a): Clock face support fusarium b): Clock base clip c:) Varnax Pivot board and alarm button pusher thingie d): trigger alignment guide, w/ at least 2 spaced screws. Showing the set trigger, when the alarm rings, the winder turns, and releases the primary trigger

View 3 From below a): Henhouse roof boards w/ cobwebs. b): Plywood Fusarium. c): Bottom of the shock absorber. d): 2x2 arm. e): Another cheap clock. f): Old baggie from previous dust prevention episode. g): Guide prevents bent trigger from slipping sideways. h:) Alarm shutoff wire. i): Secondary trigger fits under primary trigger to reduce leverage. It attaches to the side of the 2x4 to allow the ring hasp to slip off easily.

The back of the clock showing the flanged base that slips under the mounting clip (view 2-b), and plastic bag dust seal Too much dust in the hen house will work it's way inside the clock. Therefore; either sweep and dust often, or just put the dang clock in a clear plastic produce bag and fasten it with a twist tie. Pull the bag tight around the clock and poke pinholes in the bag at the location of the knobs and winders, the winders have to be on the outside (they unscrew contrary to the winding direction) carefully stretch the plastic over the knobs without making any gaping holes, and poke the winders through the plastic from the outside. The arrow points to a piece of automotive rubber vacuum tube stuck over the alarm shut-off button to cushion the pressure of the shutoff wire thingie ("Varnax Pivot"), and give it a bigger target to hit. Click here for Varnax drawings and info Every time you set the alarm you'll pull on that tube, so a wire twisted tightly around the tube holds it firm yet allows it to be removed (as opposed to glue) in case you need to replace the bag. If it still pulls off easily, wrap some fine wire or string around the stem, with glue. (string provides a ribbed gripping surface for the tube). When the glue's dry, slide the tube on like before. I recommend "Household Goop" (glue)

To adjust the primary triggers' pressure against the alarm winder, position the secondary trigger under the primary trigger, either closer or farther from the clock.

Closer allows more pressure against the winder, farther away = less pressure. With a further series of triggers this way, it's possible to hold a door weighing tons. Our coons are sometimes very bad, but they haven't yet got past a 5 lb door (A lot depends on the doors' fit though, so they can't get a tooth or finger around it). The right pressure on the trip mechanism is when the trigger rests snugly yet lightly against the winder handle, somewhere between the following extremes: (1) falling off prematurely whenever a clock manufacturer in China laughs out loud, or (2) pressing so hard that the clock base snaps off, smashing the clock gratifyingly against the far wall. Longer triggers allow a greater range of adjustability. When the right pressure is found, drive a finish nail into the wood 2x4 frame to mark the spot & use the nail as a rest for the secondary trigger.

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* This of course only postpones the inevitable, because given infinite time to get past the sliding door, Raccoons could conceivably evolve skills in higher math and explosive devices. On the bright side, Raccoons are edible, the bad news is they bite, sleep all day, fight all night, produce poorly, smell bad, and don't lay eggs. (fight 'em or join 'em ... tough choice).
I totally recommend trapping them & if you don't want to cook them, take the biggest male to the vet & have him fixed. He'll keep all the other coons out of his territory (which presumably includes your coop), and won't sire any more. And once he decides the coop is unassailable, he'll probably leave it alone. Whereas every new litter of kits would have to experiment all over. If he doesn't leave it alone, he's probably starving, so put some crunchies or something in a bowl near your neighbors property line to get him through the winter. If you don't he might starve (I guess they do that, though it seems odd) & you'll have to start all over w/ another vet bill.
Another option might be releasing them somewhere distant so they can't find their way back, but please let me disillusion you: places like Tahiti and Antarctica have strict quarantine regulations for just this reason.

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Genuine testimonials:

Thanks Bill, I feel totally enlightened. I wish I had this device 10 years ago. After losing flock after flock of ducks and ducklings, and a couple of geese we got tired of raising prime food for the coons. Cheers.

Arlene Fuller, Mendocino County 4-H

This is a rave on Bill's low-tech chicken door gizmo. Before, whenever we wanted to go out for the evening, we'd have to get a neighbor to come close the coop door. My favorite part is the shock absorber, which makes the door come down slowly, not slamming down on any poor hens. My least favorite part is the mouse trap, so Steve sets it, not me. Indeed, this invention has made life easier for us all.

Barbara Faulkner

Mission Statement
The primary objective to develop the Kaczynski "Bad Coon" Mark I concept design and hardware with direct scaleability is: directly scaleable weights, margins, loads, design, fabrication methods and testing approaches: traceability, technology, and general design similarity, to a full-scale Mark II (Goldberg) system. The "Bad Coon" is intended to demonstrate the technologies necessary to achieve systems integration within the mass fraction constraints of chicken coop door closeing devices. In addition, the "Bad Coon" will meet operational requirements outlined in the Mil-Spec CCDCD. Pg 244, sec 18, pp 7-16. The "Bad Coon" Mark II (Goldberg model) is envisioned to operate unpersoned.

Fusarium is the genus name of a group of pathogenic fungi, and has nothing to do with design engineering or structural nomenclature even though it sounds like it should. Ditto Varnax Pivot (because I just made it up). However I predict the latter will some day enter the lexicon of timeless building terminology with such handy words as "Soffit", "Header", "Fusee", and "Jefferies Tube". Because like them, it fills a reference vacuum with a concise description recognizable to anyone in the profession.