To reach the main floor of the Minnesota Inventors Congress, you must traverse a hallway of school-age dreamers and tinkerers, bubbly with enthusiasm. On wobbly card tables are displayed the fruits of their ideas and their problem-solving skills. As you pass by, they try to hook you with a look of hopeful pride, a "gee whiz" grin of accomplishment and a blitz of "better mousetrap" banter.

Just when you have made it through this maze of student inventors to reach the main floor, you are confronted with the same youthful enthusiasm from the grown-up tinkerers who imagine ways to make our lives a little easier.

The inventors who spilled out of the high school gymnasium and into a courtyard offered some fine gadgetry and keen ideas. Here are some of the ones we liked.

Seed saver Have you ever considered how much seed is dropped on the ground from the time you engage your hydraulic lift until the drive clutch on the drill stops rotating? Doug Schmilzle has. One afternoon he and his brother-in-law bought a bunch of little red flags and went to the field to flag each seed. They flagged 1,490 seeds in the 15 ft. it took for the drive clutch to disengage.

Schmilzle then went to work on the Seed Mizer, a little hydraulic cylinder that automatically engages and disengages the drive clutch to shut off the flow of seeds from the seed cup as you raise or lower your drill.

What was the difference when Schmilzle examined the 15-ft. strip after using his Seed Mizer? He counted 452 seeds.

"Seeds sitting up there on top of the ground just won't grow," Schmilzle says. "We figure that with the Seed Mizer you can save about $1.78 on every acre of soybeans you drill." He claims that his simple device should pay for itself in fewer than 400 acres. Contact Timber Creek Mfg., Dept. FIN, Rt. 3, Box 45A, Seneca, KS 66538, 888/704-5400 or circle 200.

Post puller T-posts, electric fence posts, U-posts used for signs, wooden posts - they're all a snap for the Handy Dandy Post Jack, which has an 8:1 jacking ratio. Inventor Arlow VandenBerg created a number of add-on adapters to pull those various types of posts.

Weighing just 11 lbs., the jack folds for easy transport and storage. It can also be used as a wire stretcher if you team it up with a come-along or chain.

"This is the greatest thing I've seen in years," gushes bystander Warren Blash, a veterinarian from Marshall, MN. "I've spent a lot of time wrestling posts out of the ground. Why this is so simple. It just sucks them right out of the dirt!" Contact Handy Dandy Post Jack, Dept. FIN, 1237 96th St. S.E., Hague, ND 58542, 800/894-8138 or circle 205.

Combine tray lift It used to take Wayne Noomen and his father an hour to adjust the tray below the straw chopper on their Case IH Axial Flow combine when they changed crops. His father would have to crawl inside the combine and then the two of them would undo the bolts and move first one side of the tray, then the other.

With Noomen's invention, the Tray Lift, he can do the same thing alone in about 10 minutes without crawling into the belly of the combine.

This device bolts right onto the combine. A lever allows you to raise or lower the tray and lock it into place until the bolts are retightened. "The tray brackets and linkage assembly do what my dad and I used to do by holding and locking the tray into position until the two bolts on each side of the combine are retightened," Noomen explains. Contact NooWay Enterprises Inc., Dept. FIN, 2756 181st St., Currie, MN 56123-1049, 506/ 859-2089 or circle 202.

Bale feeders Allan Stark has a pet peeve. He has a problem with fed hay getting on the ground. He explains how it is detrimental for the feedlot or pasture, how it might promote disease among horses and how the bales act as a wick to absorb moisture into the bale to cause premature spoilage.

To alleviate the problem, the Sanborn, MN, ironworker designed bale feeders that keep hay dry, clean, healthy and unspoiled. He makes one for square bales and two for round bales. He even built one with a special trailer rig for a moveable feast. "Most animals can reach over the top of these feeders," Stark says. "I think they prefer their hay that way. And we get more out of a bale if we keep it off the ground and dry." Contact SM Iron and Sales, Dept. FIN, 13219 U.S. Hwy. 71, Sanborn, MN 56083, 800/533-5326 or circle 203.

PTO shaft remover Bruce Wilson tells how he went to his local dealer to buy a device that would remove the PTO shaft on his tractor. When he learned that no such tool had been invented, he went home and sat at his kitchen table to engineer the gizmo. What he came up with is a wrench comprised of three pairs of different-sized forks and a large C-clamp.

To remove a frozen PTO shaft, you attach two pairs of the forks to the C-clamp and attach the C-clamp to the shaft. With each crank of the clamp, the forks come together and widen, creating a spreading action. The forks force the PTO off, and you haven't even lit the cutting torch. Wilson says his wrench also can be used for removing frozen combine sprockets and bearings, tie rods or any other part stuck on a machine.

The wrench comes in a steel carrying case. Included are three sets of forks for removal of a variety of parts. Price: $89. Contact PTO Shaft Remover, Dept. FIN, 1739 Bach Grove Rd., Webster City, IA 50595, 515/543-5211 or circle 204.

Jack for all lifts Bruce Hawkins' Jack Mate is a checkmate invention: Just when you're about to point out something Hawkins might have overlooked, boom, he's explaining it. The Jack Mate has wheels. It has a side deck. It has a front deck. It has two fine-tuning devices, including one at the very top. You can lean it this way and that, and you can lift from either side of the jack. You can wheel it around like a skinny dolly with a special pin that keeps the contraption from falling apart.

Hawkins claims that this jack will "fit just right." The jack ratchets seven-eighths of an inch, but its fine-tuning devices allow you to adjust it with a wrench to any desired level. "This is a jack for all lifts," Hawkins boasts.

Contact Circle H Industries, Dept. FIN, 7882 E. Hwy. 92, Hereford, AZ 85615-9478, 520/366-5540 or circle 201.

Post hole digger Jeff Vaughter claims that his post hole digger is not your father's auger-style digger. And he dug a hole to prove it.

With most of those pivot-clam diggers, you typically have a hole about 2 ft. wide at the top and 6 in. wide at the bottom of a 4-ft. hole. That's due to all the room you need to close the clams on a spade full of dirt. "What if you were right next to a building, or a hunk of concrete, and you can't get that extra width you need?" Vaughter asks.

Then he points to a hole he dug on the high school campus, one that is as straight and narrow as can be. "I dug that hole using the Hole Deal," he says.

The Hole Deal has three basic parts, each used twice. "With these three parts, as you pull the handle in, the clam pulls together," Vaughter explains.

Because there is no tapering of the hole, the amount of soil removed is minimal, saving time and effort. If the post is being cemented in, the straight sides of the hole need no forming. Contact Hole Deal, Dept. FIN, 418 W. Cedar St., Stevens Point, WI 54481, 715/341-4315 or circle 206.