Device for use in connection with fishing

A device for use in connection with fishing, comprising a container (1) adapted for dispensing of odor agents underwater, said container containing a piston device having portions (6, 7) with two different diameters, whereby one end of the portion (7) having the largest diameter is situated in a drive chamber (B) having at least one aperture (4) for inlet of water axially outside of said portion (7), while one end of the portion (6) having the smallest diameter is situated in a chamber (A) containing the odor agent, whereby the portion (7) having the largest diameter is able to force the portion (6) having the smallest diameter along the inner of the container (1), in order to force the odor agent out through at least one aperture (5) in the chamber (A) containing the odor agent, axially outside of the portion (6) having the smallest diameter, whereby means is provided for controlled dispensing of the odor agent.

FIELD OF THE INVENTION 
The present invention relates to a device for use in connection with 
fishing, comprising a container adapted for dispensing of odor agents 
under water. 
BACKGROUND OF THE INVENTION 
Many kinds of fish are completely dependent on the sense of smell in order 
to find food. This in particular applies to demersal fish species which 
often live in environments (great depths, darkness) where odor agents 
dispensed from prey animals are the only signals which enable the fish to 
discover and localize its food. Advantage is derived from this 
circumstance when fishing with tackles based on bait, as for instance 
longline and fish pot. 
Chemical analyses have shown that the concentration of odor agents 
dispensed from natural bait diminishes very rapidly. Measurements have 
been made which show that the sinking time of tackles based on bait is 
relatively long. A longline uses for instance about one hour in sinking 
down to a depth of 450 meters. This means that the bait has dispensed the 
essential of its odor agents before it reaches the relevant depth for 
catching fish, and this circumstance cannot be affected. 
Different devices for dispensing odor agents under water in connection with 
fishing are known. U.S. Pat. No. 2,791,058 shows an elongate container 
having several apertures, whereby a water soluble bladder containing an 
odor agent is situated inside the container, so that the odor agent will 
trickle out while the bladder is dissolved. U.S. Pat. No. 2,922,246 also 
shows a container containing a bladder with odor agent. The container has 
an aperture at one end and a nozzle at the other end, and by being pulled 
in the direction of the end having the aperture the bladder will be 
subjected to a certain external pressure which squeezes the odor agent 
through the nozzle. The U.S. Pat. Nos. 4,267,658 and 4,888,907 show hollow 
fishing implements which are equipped with hooks and which contain agents 
that are attractive to fish, whereby the agents are dispensed through 
apertures in the implements. U.S. Pat. No. 4,267,658 shows the use of the 
force in a line in order to cause a certain internal pressure head in a 
bellows containing the agents. 
SUMMARY OF THE INVENTION 
The present invention is based upon the recognition that the efficiency of 
fishing implements based on bait and implements traditionally not based on 
bait can be significantly increased if the dispensing of odor agents can 
be controlled in a favourable manner, both with respect to the point of 
time when the dispensing of odor starts and the duration of the 
dispensing, and that it may be favourable to vary the dispensing by 
adapting it to activity peaks which the fish may have during 24 hours. A 
use of the device with respect to fishing not based on bait may be in net 
fishing. 
The device according to the invention is characterized by the features 
appearing from the accompanying claims. 
During use under water the device according to the invention will dose a 
controlled quantity of liquid concentrate of odor agent, for instance 
finely divided octopus or mackerel, in doses or with a controlled, 
possibly a constant dispensing of the odor agent. 
The device according to the invention can be fastened to the catching 
trickle or lowered separately, and it may be equipped with electronic 
timing and/or quantity control means and a mechanical automatically 
working dosing mechanism which dispenses odor agents luring the fish to 
the catching trickle. By not actuating the device until a large pressure 
head is present due to the depth, dispensing of odor agents on depths that 
are riot of interest for catching fish is prevented The use of the odor 
agents, thus, can be performed selectively and rationally.

DETAILED DESCRIPTION OF THE INVENTION 
The device in accordance with the invention comprises a cylindrical 
container 1 divided into two chambers, A and B, having approximately the 
same volume. The diameter of the chamber B is larger than that of the 
chamber A. The bottom and top of the container 1 (as shown extending 
vertically) are closed by screw caps 2, 3 which constitute end portions of 
the chambers A and B. The cap 3 has a small throughgoing aperture 4 in the 
axially outermost end. The cap 2 has a larger (with respect to diameter) 
throughgoing aperture 5 in the axially outermost end. A dosing piston 6 
having a piston rod 9 is situated in the chamber A and protrudes through 
the aperture 5 in the cap 2. In order to resist large water pressures the 
container may externally be reinforced by ribs 8 (FIG. 2). The chamber A 
is pressure balanced in that water flows into the chamber. In the chamber 
B is provided a piston 7 having a seal 14 and a piston rod 12 in abutment 
against the dosing piston 6. 
In place of two pistons 6 and 7 a unitary (integrated) piston may be used, 
where the pistons 6 and 7 constitute piston portions. 
The piston rod 9 of the dosing piston 6 is shaped with a longitudinal 
groove 10 and circumferential recesses or "pockets" 11 for transportation 
of the odor concentrate. By moving the piston 7 and the dosing piston 6 to 
the bottom of the respective chambers A and B (at the bottom of FIGS. 1 
and 3), whereby a cavity is formed on the upper side of the pistons, the 
cavity above the piston 6 in the chamber A can be filled with odor 
concentrate. 
The device may for instance be lowered together with the catching 
implements, alternatively separately by having weigths mounted thereon, to 
the desired depth. Along the path down to the desired depth the statical 
water pressure increases, and water flows into the chamber B through the 
aperture 4 and presses the piston 7 in the direction of the chamber A. The 
water pressure creates a counterforce against the upper side of the dosing 
piston 6, but because the end surface of the piston 7 is larger than the 
end surface of the dosing piston 6, the force against the piston 7 will be 
larger than against the dosing piston 6, and both of the pistons 6 and 7 
will be forced in the direction of the aperture 5, until the piston 7 
reaches the transition between the chambers A and B (FIG. 3), where the 
container 1 has a step. The water seeps into the chamber A, forced by the 
statical water pressure, along the groove 10 in the dosing piston 6, 
whereby the pressure inside the chamber A becomes the same as on the 
exterior. The small aperture 4 in the cap 3 may be made with different 
diameters in order to adjust the rate of seeping in the water. With small 
aperture diameters the seeping in of water into the chamber B is choked, 
whereby the velocity of the pistons is reduced to the desired velocity. 
During the movement of the pistons the rod 9 is moved progressively longer 
out of the aperture 5 and dispenses in the free water on the exterior a 
certain amount of odor agent through the groove 10 in the rod 9. When a 
recess or "pocket" in the rod 9 reaches and passes the aperture 5 a 
relatively large amount of odor agent is dispensed in the free water, 
until a new zone of the rod 9 without any recess or "pocket" passes the 
aperture, whereby odor agent can only pass through the groove 10. The 
process of movement continues until the dosing piston 6 and the piston 7 
reach the end positions (at the top of the FIGS. 1 and 3) and the chamber 
A is approximately emptied of its contents of odor agent (FIG. 3). 
The rod 9 through the aperture 5 may be replaced by a valve, for instance 
an automatic check valve or an electronically controlled valve. Also the 
aperture 4 may be equipped with a valve, for instance a valve which opens 
at a predetermined external pressure (i.e. a predetermined water depth) or 
an electronically controlled valve. The controlling of the operation of 
the device may also take place by means of an electronically controlled 
unit for timing and regulation of the amount. This unit may be operative 
at one of the apertures 4 or 5, or at both. Thereby may be achieved that 
the device follows a predetermined program for dispensing of odor agent. 
Controlling of the apertures 4 and 5 is sufficient, because the pistons 6 
and 7 are driven by the statical water pressure, in response to opening 
and closing of the apertures 4 and 5, or choking of the aperture 4, 
respectively. 
The device according to the invention may be made in several sizes, adapted 
to leisure fishing as well as to professional fishing, and it may of 
course be adapted to or dimensioned for any water pressures or water 
depths. In particular for professional fishing several devices can be used 
simultaneously. 
The components incorporated in the device can be made of several different 
materials, but materials which are resistant against water are of course 
preferred. For use in salt water the components should of course also 
withstand both water and salt. Different plastics types, possibly fiber 
reinforced, and composite materials, are well suited for the container and 
the piston device, but different metals may also be used. 
The container may of course be equipped with attachment members, in order 
to be attached to for instance a line or a wire, or in order to be 
attached to fishing implements for being lowered therewith. Moreover, the 
container may be shaped for mounting of electronic equipment.