The US Patent and Trademark Office Tuesday published an Apple request for a patent of a system designed to protect falling storage devices by enabling sensors within the devices to enact a temporary safety protocol if any subtle change in gravity or acceleration is detected.

Apple filed a request for the patent in July 2004, and Monday's move by the patent office launched the public review process, said a spokeswoman for the agency. The process generally takes about 30 months, she noted.

The documents list Paul James Wehrenberg of California as the inventor of the system. Apple officials did not respond to a request for comment on the company's plans for the patented system.

According to patent office documents, the technology for which the patent has been requested can sense when data storage devices encounter a "free fall" or drop from an at rest position, and other types of accelerated movement. The documents note that the technology would be useful in small storage devices found in notebook and personal computers, digital cameras and computers installed in vehicles.

The documents say that the sensors can detect movement and then alert technology that would secure the data read/write head by temporarily parking it in a safe position. That process enables the system to "prevent or mitigate" damage when a storage device is dropped onto concrete, asphalt, down stairs or onto other hard surfaces, according to the documents.

While it acknowledged in the patent request that several sensors that can stop excessive vibration from causing harm to stored data are now available, Apple said that its system covers new ground because it can accurately measure changes in force, gravity or acceleration prior to impact.

In the documents, Apple said that the technology could also prove valuable in other types of devices and equipment, including elevators and amusement park rides. In one example, Apple said the invention could detect gravity acceleration in a dropped camera and activate the inflation of a cushion to protect the device.