Wire Dispenser

Abstract

An outside payout wire dispenser including a specially configured spool; e coiled on the spool under tension; and an insulative coating which binds the outside layer of wire on the spool. The spool may be specially configured with predetermined ratios of hub diameter to flange diameter, hub diameter to flange diameter to length of spool, predetermined flange angle, and predetermined pitch angle of the wire wound on the spool. Further, the invention may include a pool cover which has a necked down wire exit portion with a predetermined angle.

Description

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

Wire dispensers are characteristically employed in the wire guided torpedo system. In this system control signals are telemetered from a mother vehicle over a very fine insulated wire to the torpedo. Since it is anticipated that both the vehicle and the torpedo will be moving in the water the wire is disposed in a coil at both locations. Accordingly, as either or both the vehicle and torpedo move in the water the wire is freely payed out and lays substantially motionless in the water so that there is practically no strain thereon.

At the torpedo location the payout coil is disposed within a container which has an exit opening. In many applications a long slender tube extends aft in the torpedo from the exit opening of the container and wire from the payout coil extends through the tube to the mother vehicle. Originally, all wire guided torpedoes were controlled by an inside payout system in which the wire was dispensed longitudinally from the center of a wire coil. In order to retain these unsupported coils in position it is necessary that an adhesive be added to the wire during the winding process so that the wire coil will not collapse upon itself. This adhesive is especially troublesome for torpedoes exceeding speeds of 40 knots since it will accumulate in large globules on the wire and in the payout tube, causing blockage and breaking strain on the wire during payout.

Another problem with the adhesive is the difficulty in applying it uniformly throughout the coil of wire during winding, resulting in undesirable electrical characteristics upon seawater penetration and undesirable variation in wire strain as the wire is payed out from the coil. In order to overcome some of the problems associated with inside payout systems attempts have been made to design a workable outside payout system. Here again the adhesive was employed and as a result most of the problems discussed hereinabove were still present. An additional problem associated with previous outside payout wire dispensers is that considerable rubbing friction is generated between adjacent wires during payout, resulting in several loops of wire moving simultaneously from the coil and forming snags during operation.

SUMMARY OF THE INVENTION

We have discovered that the aformentioned problems associated with prior art wire dispensers for torpedoes can be overcome by using an outside payout wire dispenser in which no adhesive is employed between inside layers of wire. This has been accomplished by wrapping the wire under tension on the spool and then coating the top layer of wire with an insulative binder for retention and protection purposes. At the commencement of payout the wire breaks the top coating of insulative binder and the remainder of the wire is held under tension on the spool in the proper position during payout due to the slight prestressing of each loop of wire. The problem associated with several loops of wire moving simultaneously off of the spool has been overcome by providing a pitch to the wound wire which eliminates rubbing friction between adjacent loops of wire. Further, the spool configuration is important since it determines the maximum range and speed of the torpedo. In order to optimize range and speed we have discovered highly desirable values of the following parameters: ratio of hub diameter to flange diameter of the spool; ratio of hub diameter to flange diameter to length of the spool; and flange angle. Further, a highly desirable angle for the necked down portion of a spool cover has also been discovered.

STATEMENT OF THE OBJECTS OF THE INVENTION

An object of the present invention is to overcome the aforementioned problems associated with prior art wire dispensers.

A further object is to provide a wire dispenser for a wire guided torpedo system in which breakage during payout will be minimized.

Another object is to provide a wire guided torpedo wire dispenser in which mechanical and electrical problems are minimized.

Other objects and many of the attendant advantages of this invention will be readily appreciated as it becomes better understood by reference to the description and accompanying drawing which follows.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an ocean view of a submarine controlling a wire guided torpedo.

FIG. 2 is an exploded side view, partially in cross-section, of a torpedo wire dispenser.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing there is shown in FIG. 1 a torpedo 10 which is being guided by a very fine insulated wire 12 from a submarine 14. In the after portion of the torpedo is a wire dispenser which is illustrated generally at 16 in FIG. 2. The wire dispenser may include a spool 18, wire 20 wound on the spool, and a spool cover 22. The spool 18 has a hub 24 and forward and after flanges 26 and 28 respectively. Aft of the cover 22 is a generally conical necked down fairlead 34. The fairlead 34 has a payout tube 38 which exits the torpedo for guiding the wire therefrom.

The spool 18 may be mounted about a housing 40, which may be used for torpedo electronics, and may be held in place by a retainer snap ring 42 which fits within annular groove 44. The housing 40 may be longitudinally retained within the torpedo by a snap ring 46 and similar snap rings 48 and 50 may be utilized to retain the cover 22 and the fairlead 34 in their respective longitudinal positions. Each of the snap rings 46, 48, and 50 snap within a respective annular groove (not shown) about the interior wall of the torpedo. The fairlead 34 may abut a rear wall of the torpedo for retention purposes.

In prior torpedo wire dispensers the wire was wound with an adhesive which has been quite troublesome. The adhesive collects in globules at the fairlead 34 and within the payout tube 38 causing breaking strain on the wire during payout. This problem and other problems associated with the adhesive have been overcome by winding the wire 20 on the spool 18 under tension and retaining the top layer of wire with a coating of insulative binder 41. Also, we have discovered highly desirable values for the pitch angle of the winding of the wire 20 on the spool so as to overcome the problem of several loops of the wire moving simultaneously off of the spool during payout. The optimum tension or prestressing of the wire on the spool and the pitch angle of winding depends on the wire size and insulation thickness. Our experiments have shown that the following tensions and pitch angles have worked satisfactorily for the various wire sizes.

TABLE I ______________________________________ Wire Wire Insulation Tension Pitch Size AWG Thickness Mils Pounds Wires/inch ______________________________________ 24 9 6 12 25 6 8 18 25 8 8 22 26 9 8 14 ______________________________________

A material which has been found highly satisfactory for the insulative binder 41 is enamel. After the wire has been wound on the spool under tension the coating 41 may be formed by spraying a layer of enamel about 10 mils thick on the top layer of wire. The enamel layer 41 should completely cover the top layer of wire and extend slightly onto the flanges 26 and 28 so that it not only binds the wire but also seals it from the seawater environment. This sealing is important to prevent seawater from unevenly soaking into the coil of wire and causing undesirable and unpredictable changes of the inductance and capacitance effects of the coiled wire.

The spool configuration is quite important since it determines the maximum range and speed of the torpedo. As shown in FIG. 2, d represents the hub 24 diameter, D represents the aft flange 28 diameter, L represents the length of the spool, and .alpha. represents the angle of the flange 28 to a plane perpendicular to the longitudinal axis of the spool. The most critical parameter in the configuration of the spool 18 is the d/D ratio. For torpedo speeds greater than 40 knots this ratio should be greater than 0.5. In our experiments we have found the following d/D ratios to be highly desirable for the wire payout speeds shown.

TABLE II ______________________________________ Payout Speed FPS d/D ______________________________________ 50 .58 100 .71 ______________________________________

Further, we have found the following d/D/L ratios to be desirable for the wire payout speeds shown.

TABLE III ______________________________________ Payout Speed FPS d/D/L ______________________________________ 50 .06 100 .08 ______________________________________

We have also found that the most desirable angle .alpha. for the flange 28 is a range between 9.degree. to 16.degree.. It should be noted that the outer diameter of the after flange 28 is rounded since the wire will be drawn thereover during payout. The surface in this area should be at least 63 RMS. A spool made of plastic easily provides this desired smoothness. The most desirable angle .beta. for the necked down portion 34 of the cover 22 is approximately 120.degree. for wire payout speeds between 50 to 100 ft/sec.

In the operation of the wire dispenser 16 the wire 20 is uncoiled from the spool 18 and travels through the fairlead 34 and payout tube 38 as the torpedo 10 moves through the water in response to telemetered commands from the submarine 14. At the commencement of wire payout the top layer of wire breaks through the very thin insulative coating 41 and this coating disperses in the seawater as minute particles through the payout tube. The wire which is still coiled on the spool 18 is now exposed to the seawater. However, uneven soaking of seawater into the coil does not take place since the wire is uncoiling quite rapidly. Even though the torpedo 10 may be accelerating or deaccelerating according to telemetered commands for the submarine, the tension or prestressing of each loop of wire on the spool causes the loops of wire to retain their position until they are pulled for their individual release therefrom. The pitch angle of the winding of the wire on the spool prevents adjacent wires from rubbing on one another so that the release of one wire loop from the spool does not simultaneously uncoil an adjacent loop from the spool. The aforementioned desirable values for the various parameters of the spool 18 and the fairlead 34 (necked down portion of the cover 22) enable optimum range and speed of the torpedo 10.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Claims

We claim:

1. An outside payout wire dispenser comprising:

a spool;

non-binding wire wound on the spool under tension;

an insulative coating which binds the outside layer of wire on the spool;

the wire size being in a range from 24 to 26 AWG and having an insulative jacket of a thickness in a range of 6 to 9 mils; and

the tension on each loop of wire on the spool being in a range from 6 to 9 pounds.

2. An outside payout wire dispenser as claimed in claim 1 wherein:

the insulative coating is sprayed on enamel and seals the wound wire from the outside environment.

3. An outside payout wire dispenser as claimed in claim 2 wherein:

the pitch angle of the winding of the wire on the spool is in a range of 12 to 22 wires per inch along the spool.

4. An outside payout wire dispenser as claimed in claim 3 including:

said spool having an aft flange over which the wire is payed out; and

the d/D ratio of the spool being in a range of 0.58 to 0.71 where d = the diameter of the spool hub and D = the diameter of the flange.

5. An outside payout wire dispenser as claimed in claim 4 wherein: the d/D/L ratio is in a range of 0.06 to 0.08 where L = the length of the spool.

6. An outside payout wire dispenser as claimed in claim 5 wherein:

the angle of the after flange from a plane normal to the longitudinal axis is in a range of 9.degree. to 16.degree. .

7. An outside payout wire dispenser as claimed in claim 6 including:

a cover mounted about the spool, said cover having a conical shaped necked down portion aft of the flange; and

the necked down portion of the cover having a lesser included angle of approximately 120.degree. .