When Baltimore County resident David Ward fell off a tower in a swimming accident nine years ago, he was paralyzed from the shoulders down. He could sit up but had no use of his arms, wrists or fingers, making even eating a major chore that usually required assistance.

Since 1984, however, Ward, now 39, has been using an electronic hand-closure device developed by a group of volunteer engineers in the Baltimore area.

The device is wired from Ward's shoulders, so that when he tenses his shoulder muscles, the machine sends an electronic signal down his right arm to the device, which causes the involuntary opening or closing of his thumb and first two fingers.

The device, which allows the former light industrial equipment salesman to grasp objects such as a fork or a toothbrush, has granted him a degree of independence that he never thought possible. "If you could visualize not being able to pick up a fork for seven years, and then all of a sudden being able to, it is hard to describe," Ward said.

The device is one of more than 10 created by Volunteers for Medical Engineering, Inc., an organization that uses engineering and aerospace technology to make free devices for disabled people. Another 10 to 15 such devices are being developed by the volunteer engineers.

The group, which works with hospitals and rehabilitation centers in the Baltimore area, was started in 1982 by John Staehlin, a radar antenna engineer for the Westinghouse Defense and Electronics Center near Baltimore-Washington International Airport.

Initially made up of a few physicians and some Westinghouse engineers, the organization has grown to about 200 members, including machinists, draftspersons, artists, lawyers, accountants and secretaries. More than half are Westinghouse employes, Staehlin said, and most are from the Baltimore area.

The Baltimore volunteers work during their free time and lunch hours, Staehlin said, and do everything from drafting designs of new inventions to soliciting donations of money or materials to producing the group's quarterly newsletter.

Annual donations have jumped from less than $1,000 in 1982 to more than $75,000 in 1985, most of it from Westinghouse, Staehlin said.

Among the devices the group has produced:

*A "blink-writer" that helps paralyzed people operate a modified word-processor by intentionally blinking into a light-sensor attached to a special pair of glasses.

*A modified mobile walking frame, a kind of stand-up wheelchair, in which a disabled person can move around on a four-wheeled platform.

*An overhead rail and trolley, which help bedridden patients get into wheelchairs.

None of the devices is patented. "Our philosophy is to make them public knowledge and let other people make them if they want to," Staehlin said.

Arthur Siebens, director of rehabilitation programs at Johns Hopkins and Good Samaritan hospitals in Baltimore who works with the group and refers patients, said it is unlikely that a private company would take the time with such inventions.

It took volunteer engineers more than two years to develop the hand-closure device, for instance, which had to be custom-made for Ward.

"There is no way that device could have been made commercially at a cost he Ward could afford," Siebens said.

The volunteers have made about 20 blink writers, the most popular of their inventions, Staehlin said. Operated by the blinks of the user, a cursor scans a video screen filled with a menu of information, ranging from numbers and letters to basic commands and phrases.

There is a character labeled "TV," for instance, and if a patient wants to tell a nurse to turn on the television set, he or she just blinks when the cursor scans over that character.

Dr. Annamaria Basili, chief of Audiology and Speech Pathology at Baltimore's Fort Howard Hospital, where several patients have used the machine, said it is "absolutely terrific" for persons suffering from amyotrophic lateral sclerosis (Lou Gehrig's disease), a disease in which the mind retains the capacity to think but the body deteriorates.

The device may not prolong such a patient's life, "but boy, when you talk about quality of life, there is a big difference."

That, said Staehlin, is exactly why the volunteers offer their services. "There is no need for any other reward," he said.