1. Field of the Invention
This invention relates generally to the field of crab traps, and more particularly to a commercial crab trap that is uniquely configured in the shape to increase the number of crabs caught by diverting the crabs toward the gate of the trap.
2. Background Art
Commercial crab harvesting involves the use of many expensive crab traps that are taken out to sea, lowered to the ocean floor where their location is marked with a floating buoy, and left to accumulate crabs. The fishing vessel returns after a couple of days, hopefully locates the buoys that mark the crab traps, and hoists the crab traps aboard to retrieve the catch.
Traditional commercial crab traps comprise a frame that is covered by a wire mesh. They will also typically have some type of one-way gate that the crab can crawl through to reach the bait inside the trap and an access door that is used to load the trap with bait and to remove the catch once the crab trap is retrieved. The most common crab traps used by commercial crab harvesters are shaped either like a rectangular box as is shown in U.S. Pat. No. 4,184,283 (Wyman), or a circular cage like that shown in U.S. Pat. No. 2,760,297 (Buyken). Generally, the one-way gates are either positioned in the center of one or more of the side walls of the rectangular shaped traps, or they are equally spaced around the circumference of the circular shape traps.
A commercial crab fishing vessel can set hundreds of crab traps at any one time. Each of these crab traps must be filled by hand with bait and also emptied of their catch by hand. The current practice is to fill the crab traps through access doors that are secured shut by using a heavy rubber strap with a hook on its end (similar to a bungee cord). An example of this type of strap is shown in U.S. Pat. No. 4,509,288 (Sheperd). To bait the trap the rubber strap is stretched by hand until the hook can be pulled free and the rubber strap is retracted. This allows the access door to be opened. The trap is then filled with bait, the access door closed, and the rubber strap is stretched by hand over the access door until the hook can grab the mesh under enough tension to keep the access door closed. Stretching this rubber strap by hand hundreds, if not thousands, of times over the course of a season often leads to repetitive motion injuries and considerable soreness and pain.
A commercial crab trap is typically made from iron that is often rubber coated. Iron is the material of choice because it is inexpensive and its weight helps to hold the crab trap in the same position on the ocean floor. Iron, however, is particularly susceptible to corrosive effect of the sea water which means that the crab traps rust over a few years of use and have to be replaced. Largely because crab traps are so often lost, the industry has been hesitant to make the crab traps from more expensive materials like stainless steel. Although marine aluminum (50/58) or (60/61) is relatively inexpensive and strong, the industry has not used it because it is not thought to be heavy enough to anchor the crab trap to the ocean floor.
A search of the patent literature has disclosed a number of other patents.
U.S. Pat. No. 4,411,092 (Lalancette) shows a trap in which there are walls which converge upwardly and laterally to an upwardly facing entrance opening in the area at which tee walls meet. The fish enter through the opening and are trapped. There is a door 9, for the removal of the caught fish.
U.S. Pat. No. 3,772,818 (Gardina) shows a crustacean trap in which there are funnel shaped elements 39, through which the crustacean enters. The crustacean is removed through door 44.
U.S. Pat. No. 4,730,892 (Cos et al) shows a lobster trap in which prey falls to the bottom of the structure after entering.
U.S. Pat. No. 3,440,758 (Prince) shows a collapsible crab trap in which there is an upper and lower solid ring that between the mesh sides are stretched. The mesh walls converge to points at which there are entrance openings.
U.S. Pat. No. 2,163,973 (Benca et al) show a fish trap in which there is an entrance funnel area 17, through which the fish enter.
U.S. Pat. No. 991,7450 (Mournian) shows a fish trap formed with converging walls at the entrance.
U.S. Pat. No. 605,834 (Albury) shows a fish trap in which there is an entrance on one side where the walls converge.
British Patent specification No. 368,686 shows a device to trap fish where there is a circular frame, and a source of light is positioned at the center of this frame. The fish are attracted to the light and swim toward the trap. The trap has six cone shaped (funnel shaped) wire members H-1, each of which defines a radially inwardly extending converging passageway. There is a downwardly extending net f closed by a drawstring g.
USPTO Backgrounds
USPTO Backgrounds