Safety Brake Helps Put High-Def Eye in the Sky

Next time you watch a major sports event on TV, especially those in high definition, you could be seeing it through the lens of an ActionCam HD from Action- Cam (actioncamhd.com) Tulsa, Okla. Thanks partly to Ogura RNB-20G spring-applied brakes, ActionCam suspends a camera moving at up to 60 mph over the field of action — and that field can cover a million square feet. (Current “flying” cameras are restricted to covering 250,000 ft².)

The setup is relatively simple: Four cable reels sit in the corners of the venue. An Ogura brake mounts on the central shaft of each reel. And from each reel, lightweight, high-tension rigging cables, along with a military-grade fiber-optic cable, are strung 90 ft or higher to the top of the venue’s corners then to the center of the field, where they meet to support a camera. The cables measure 1/8 in. in diameter and have a brake strength of over 2,500 lb. The camera weighs about 100 lb, and if the cables are rigged properly, no static or dynamic force should exceed 250 lb. So the system has a safety factor of 10 to 1.

Using a computer controller, operators reel in or let out cable from the four reels, letting them move the camera down and across the field, as well as pan and zoom using two joysticks. The camera itself is a Fujinon HD-grade model with an 18× zoom lens. The camera is fully stabilized linearly and rotationally.

For safety, a fifth reel and Ogura brake are mounted midfield and its cable attaches to the camera. If the ActionCam controls detect a malfunction, or if any of the four corner reels lose power, this safety reel pulls the camera up and away from players and spectators. The safety cable incorporates a Kevlar component, making it strong enough to suspend the camera securely. It also carries redundant fiber optics and low-voltage power and can take over full control of the camera and receive video. Another safety feature is that the camera is programmed to remain at least 12 ft above the field. (And if a ball hits the camera or cables in an NFL game, it is ruled a dead ball and they replay the down.)

Because the camera is, in effect, computer controlled, it can be programmed to repeat motions, including panning and zooming. This should make it a valuable tool for movie and television production. According to the manufacturer, ActionCam can take large sweeping shots and make complicated camera moves on live-action scenes that even computer-generated special effects can’t duplcate.