DURHAM, Conn. (AP) _ A teen-ager who rode her horse at the same Massachusetts stable where actor Christopher Reeve kept a horse hopes an equestrian ``seat belt'' she's invented will prevent the kind of fall that left the ``Superman'' star paralyzed.

Kimberly Kojima, 18, received a patent last month for a bungee-like restraining apparatus intended to keep a rider in the saddle rather than pitching headfirst over the horse's neck when the horse stumbles or stops suddenly.

She has yet to find a manufacturer and some riding experts worry the restraining belt could cause more injuries than it would prevent, but Miss Kojima is pressing ahead with her project. She said her invention could be especially useful to disabled riders and young children.

Reeve's spinal cord was severed May 27, 1995, when he fell headfirst from his horse in a jumping competition in Culpeper, Va. He had boarded a horse at DeMayo's Bonnie Lea Farm in Williamstown, Mass., where Miss Kojima sometimes saw him when she rode her thoroughbred, Frank.

``When the accident happened,'' she said, ``the whole barn was devastated.''

Miss Kojima, a senior at a private school in Connecticut as well as an avid horsewoman and aspiring veterinarian, took a similar spill from a horse when she was 8 and broke her left arm.

``Riding is a dangerous sport,'' Miss Kojima said. ``A helmet protects your head but it doesn't protect your neck. I wanted to see what I could do.''

She started with some rough drawings and began consulting with her father, Ray, an electrical engineer.

``Christopher Reeve was well-known and well-liked up here,'' her father said in a telephone interview from his Massachusetts home. ``When he had his accident, my daughter felt very badly about it. She started trying to figure out how to prevent this. She's kind of a funny kid. Once she gets her eye on something, she won't let go. She's like a bulldog.''

What she came up with is a device with straps, which encircle the midsections of both horse and rider, connected near the back of the saddle by a hollow breakaway rod holding a spring and a length of stretchy cord.

If the horse were to stop suddenly, the cord and spring would keep the rider from being thrown forward but ``give'' enough to permit some sideways movement. If the rider were falling off to the side at an angle greater than 15 degrees from the horse's head, the rod would detach and allow the rider to fall or jump free of the animal.

Kojima himself doesn't ride but applied his engineering expertise to his daughter's project, calculating angles and forces. The patent, dated April 7, doesn't guarantee production but simply excludes others ``from making, using, offering for sale, or selling'' a similar invention or importing it into the United States.

Reeve, a paraplegic since his accident, was at a speaking engagement in Virginia and unavailable for comment on the invention he inspired, a spokeswoman said Friday.

Miss Kojima says a maker of equestrian safety equipment, which she declined to identify, is examining her prototype to determine if it's feasible. But several equestrian experts who were asked to examine the diagrams and descriptions of the invention included in her patent materials expressed strong reservations about its safety.

``I just can't even imagine anyone in the safety industry supporting it,'' said Jan Dawson, president of the American Association for Horsemanship Safety in Fentress, Texas. ``I think it's more important to be able to come off the horse than to stay on.''

Dawson said a rider could be trampled if the rod failed to detach and left the rider tied to the horse.

Louisa Fedora, Miss Kojima's riding instructor at Movado Farm in Durham, has not seen the prototype but said she ``wouldn't want to be attached to the horse. You want to be able to get free.''

Dr. Doris Bixby Hammett of the American Medical Equestrian Association in Franklin, Ky., worried that the rigid rod could injure the rider if the horse were to rear suddenly and send the rider backward.

``I feel that a device which keeps the rider mounted increases the risk of riding. There are times in which the emergency dismount is the safest way out of a dangerous situation,'' she said. ``Usually I do not want to remain on a bucking horse. Anything that forces me to remain is dangerous.''

Miss Kojima, who will enter the University of Vermont's veterinary medicine program this fall, noted that riders were slow to adopt cushioned safety vests that protect ribs and spines but use them widely today.

``In the equestrian world, anything new nobody likes,'' she said. ``It's a very traditional world of sports.''