1979 - Volume #3, Issue #3, Page #04[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Air-Powered Door Opener
"The energy savings are terrific with this door. In winter, you lose only a fraction of the hot air lost with a conventional door opener. And, you don't waste time standing around watching a door open. Just flip the switch and go through," he explains.
The new-style door opener can be installed on new or existing overhead doors with torsion spring action. Here's how it works:
A sprocket is fitted to one end of the torsion spring and a drive chain run between the sprocket and two air-powered cylinders mounted on the wall. A piston from each cylinder is attached to either side of the chain. When activated, air shoots the piston out of one cylinder, pulling up the chain, turning the sprocket and raising or lowering the door. When the other cylinder is activated, it pulls the chain in the other direction, forcing the first piston back into its cylinder and moving the door in the opposite direction.
Length of the air cylinders varies with the height of the doors, but they are always half as long as the door is high. For example, a 12-ft. high door needs 6-ft. cylinders, and a 14-ft. door needs 7-ft. cylinders.
The opener works on overhead doors of any width from 8 to 16 ft. high, but only on those with torsion spring action. It operates off 40 to 120 lbs. of pressure, depending on weight of the door and how fast you want it to open. Hedrick says most any small portab'e air compressor will keep the opener charged with air. A 10-gal. tank of air will open and close the door 20 to 25 times without repressurizing.
"Until you've seen this opener work, it's hard to believe how revolutionary it is," says Hedrick. "It opens and shuts in a flash, yet you can easily stop it with your hand if you ever accidently close it on yourself or machinery. The two cylinders are balanced on cushions of air which cushion the movement of the door. If electrical power went off and you couldn't run the air compressor, you could open the door just as easily by hand as you could without the air system attached. With the air pressure turned on, however, the door is locked to the floor."
The air-powered opener is easily installed by do-it-yourselfers, according to Hedrick. It consists of the drive sprocket and chain, two air cylinders and the control box. Optional radio remote control is available, as well as air compressors, if needed.
Cost of the door opener is $300 to $600, depending on door size.
For more information, contact: FARM SHOW Followup, Lloyd Hedrick, Sr., Hedrick Manufacturing, Box 100, Hedrick, Iowa 52563 (ph 515 653-2123).
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