When traffic accidents occur, child safety seats can help protect young passengers from injury. But in many vehicles, these auxiliary seats are not installed properly, reducing their effectiveness. To address this problem, three Johns Hopkins undergraduates have invented a low-tech tool that makes it much easier to compress a safety seat against a car's permanent seat to ensure a snug fit and maximum protection for the child.

The device, dubbed Main Squeeze, was designed and assembled over the past school year by three mechanical engineering majors enrolled in the Senior Design Course.

David Apple, Eric Park and Jennifer Parker with the tool they designed to ease the installation of a safety seat. The work was done for the Senior Design Course in mechanical engineering.

First, the tool is attached to a car's seat belts or to part of the permanent car seat. Then the user simply turns a crank that slowly applies up to 200 pounds of compression to the base of the child seat. Main Squeeze holds the child seat in this snug position, leaving the installer free to fasten it tightly into place with the car's seat belts or built-in LATCH (Lower Anchors and Tethers for Children) system. When this installation is completed, the Main Squeeze tool is easily removed.

The student inventors--David Apple, 21, of Herzlyia Pituach, Israel; Eric Park, 22, of Great Neck, N.Y.; and Jennifer Parker, 22, of Newburyport, Mass.--were assigned last fall to create a device that would make it easier to install child safety seats in vehicles. The project was sponsored by the Center for Injury Research and Policy at the Johns Hopkins Bloomberg School of Public Health. "Researchers have determined that too many of these seats are installed improperly, exposing children to a greater risk of injury," said Michael Ho, a staff member at the center who monitored the project. "We asked students to come up with a solution."

In their research, the students learned that snug installation of a child seat is so difficult that many parents seek help from specially trained police officers, firefighters and public safety aides. Snug installation is achieved if less than one inch of movement occurs on each side of the safety seat when it is severely shaken laterally by an average size adult male. When installation assistance is not available, parents are left on their own to fit the child seat securely. "The problem is, to compress the child seat into the car you have to climb inside and apply pressure with your knees," Apple said. "That's not always easy to do."

Added Park, "A parent or grandparent who is too tall or doesn't weigh enough or has back problems may not be able to get a snug fit. Our goal was to come up with a lightweight, portable, relatively inexpensive tool to provide the compression that's needed."

The students' design is decidedly "low-tech," involving no motorized parts or electricity. "We used a large steel acme screw, an aluminum crossbar and a padded wooden block mounted on a ball joint," Parker said. "You put the block into the base of the child seat, attach the crossbar to the car's seat belts or to the bottom of the permanent seat and then simply turn the screw with a crank."

The screw applies the necessary force to get a tight seal and holds the child seat in place until it can be fastened into the car via the car's seat belts or built-in LATCH system (required on all car models introduced after September 2002). The student inventors created an assortment of attachments so that Main Squeeze can be used on a variety of newer and older model cars.

At the beginning of the school year, the students were given a budget of $8,000 to design, assemble and test their invention. Including the cost of the back half of a 1984 compact car used for testing, the students said they spent roughly half that amount to complete the Main Squeeze project. They plan to patent their prototype and look for a company interested in mass-producing the device.

The child safety seat installer was one of 11 Johns Hopkins projects completed this year by undergraduates in the Senior Design Project course. The class is taught by Andrew F. Conn, a Johns Hopkins graduate with more than 30 years of experience in public and private research and development. Each team of three or four students, working within budgets of up to $10,000, had to design a device, purchase or fabricate the parts and assemble the final product. Corporations, government agencies and nonprofit groups provided the assignments and funding. The course is traditionally a well-received hands-on engineering experience for Johns Hopkins undergraduates.