| 摘要 |
An improved manually operated signaling device to produce audible sound underwater. An air tight housing comprising a tubular member with end-caps permanently sealing each of its two ends and having contained within a metal echo-chamber fixed at each end of the housing plus a solid metal piston member. The inside diameter at each end of the housing is step-relieved so as to accept and hold fast the outside diameter and depth of the echo-chambers. The echo-chamber is a cylinder having one end open and one end closed with its closed end inserted into the ends of the housing. The outside diameter of the piston is slightly smaller than the inside diameter of the housing. The piston also has a length greater than its own diameter which allows the piston free movement along the longitudinal axis of the housing. A colored thin walled jacket may optionally cover a part or all of the housing exterior. A ring may be connected to the exterior of one of the housing end-caps for attaching a lanyard. The housing, end-caps and jacket are preferably made of polyvinyl chloride commonly referred to as PVC. The housing end-cap ring and piston are preferably made of stainless steel. The echo-chamber is preferably made of a malleable metal. A method of use is to aim the longitudinal axis of the housing toward another diver and shake the device with a reciprocal movement causing the piston to move along the longitudinal axis of the housing thus creating audible sound as the metal piston forcibly impacts the echo-chambers.
|
