Spool for wire deployment

Abstract

A spool for wire deployment having a cylindrically-shaped body upon which is wound a wire. The body is made of a pair of sections separated by a first braking ring. A second braking ring is adjustably mounted on the body adjacent the first braking ring. In operation the wire passes through the braking rings and at a preselected time during the unwinding of the wire from the spool, the braking rings apply a braking force thereto thereby preventing any damage to the wire during the unwinding procedure.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to wire deployment, and, more particularly, to a spool for deploying wire from a high speed rocket.

It has been necessary, for experimental purposes, for example, to simulate a large rocket, along with the conducting portion of its exhaust plume, to trigger, attract and direct natural lightning discharges and to produce the related quasi-electrostatic effects. This simulation has been accomplished by a rocket-wire system which would trigger a lightning stroke in a controlled fashion. Thin wires launched by and/or from a rocket have been used to trigger lightning strokes. For this work it is necessary to utilize a special reel or spool capable of rapidly unwinding wire therefrom.

The wire may be deployed from the rocket at speeds up to about 500 feet per second relative to the rocket and then brought back up to rocket speed by application of a "braking" force. The wire may remain connected to the rocket to increase its electrical length for lightning triggering or other experimental purposes. The wire may also be simply deployed into the air without braking. Such a spool for deploying wire must therefore be designed for operation within rockets reaching velocities in the order of 2,500 ft per second with initial accelerations in the order of 100g.

The problems encountered in such an operation and produced by such a spool have been numerous. For example, the spool must be capable of deploying wire at high velocities and yet also be capable of braking the wire without also causing a break in the wire itself. Heretofore this combination of results have not been achieved in a reliable and economical manner.

SUMMARY OF THE INVENTION

The instant invention sets forth a spool for wire deployment which overcomes the problems set forth hereinabove. The spool making up this invention fits within the nose of a rocket and incorporates therewith a cone-and-funnel arrangement which reduces whipping and kinking of the wire as it is dispensed. The spool itself is made up of an upper and lower section separated by a braking ring. Wire is wound on the spool above and below the brake ring. The free end of the wire passes over a lower guide ring which helps prevent wire slippage during wire deployment. A hollow metal drag cone is attached to the end of the wire and exposed to the air outside the rocket.

Wire deployment takes place at a predetermined altitude by the severing of a line holding the drag cone. The drag on the cone then begins pulling the wire from the spool. Since the wire is moving with considerable velocity relative to the rocket, the sudden snubbing when the last turn of the wire comes off the spool or bobbin might result in wire breakage. Such is not the case in the instant invention since the spool of this invention is wound in two sections an upper and lower section. The wire is first deployed from the lower section. When the wire is all deployed therefrom, a braking force is automatically applied by a brake before deployment from the second or upper section. The brake is made of a pair of rings which allow the wire to pass therebetween during unwinding from the upper spool section. The pinch rings of the brake are made of smooth steel with the gap between them capable of being adjusted to give a desired frictional braking force.

It is therefore an object of this invention to provide a spool for wire deployment which permits smooth, even wire release at high speeds.

It is another object of this invention to provide a spool for wire deployment which overcomes the problems or wire breakage during deployment.

It is still another object of this invention to provide a spool for wire deployment which is economical to produce and which utilizes conventional, currently available components that lend themselves to standard mass producing manufacturing techniques.

For a better understanding of the present invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevational schematic view of the spool of this invention shown in position within a rocket; and

FIG. 2 is a detailed side elevational view of the spool of this invention shown partly in cross-section and with a portion of the grooves and wire shown thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to FIG. 1 of the drawing which shows in schematic fashion spool 10 of this invention, utilized for wire deployment, mounted within a conventional rocket 12. The basic idea of this invention is to have wire 14 wound around the bobbin or spool 10 in such a manner as to pay out wire 14 during rocket flight. Spool 10 is secured within the payload section of rocket 12 and feeds wire 14 from the bottom thereof through a cone and funnel arrangement 16 thereby reducing whipping and kinking of wire 14. The cone and funnel arrangement 16 feeds wire 14 into pipe 18 which is attached by any suitable fasteners 20 to the outside of rocket 12. A hollow metal drag cone 22 is attached to the end of wire 14 at the rear end of pipe 18 a short distance forward of the rocket exhaust plane. In this manner cone 22 is exposed to air flow but not to the exhaust flame. A second wire 24 is fixedly attached at one end thereof to rocket 12 and at the other end to wire 10 in order to hold cone 22 in place. At a predetermined time during flight wire 24 is severed by any suitable line cutter (not shown) and thereby releases cone 22 into the air stream causing the drag thereon to pull wire 14 out from pipe 18 and in turn from spool 10. As set forth in detail hereinbelow, this invention provides a spool 10 which is capable of quickly deploying wire as well as preventing the breaking thereof.

Reference is now made to FIG. 2 of the drawing which shows in detail the various elments which make up spool 10 of this invention. Spool 10 is in the form of a cylindrical body 30 having machined grooves 32 (only partly shown in FIG. 2) circumferentially spaced therearound. As seen in FIG. 2, spool 10 is divided into an upper and lower sections 34 and 36, respectively, by a ring 38 located around body 30 substantially midway between the two ends thereof. Ring 38 is of a diameter slightly larger than the diameter of the wound wire about body 30. Formed at the bottom of cylindrical body 30 or fixedly attached thereto is a cone shaped end piece 40 having a ring 42 at the top portion thereof substantially indentical to ring 38. This lower guide ring 42 helps prevent wire slippage during wire deployment.

At the top section of cylindrical body 30 is a cylindrically threaded member 44. Member 44 threadly engages a brake mechanism 46. Brake 46 is made of a cylindrical configuration, formed with an internally threaded segment 48 at one end thereof for engaging member 44 and having a ring-shaped member 50 at the other end thereof. Member 50 acts as a pinching brake in conjunction with ring 38. For the operation of this brake it is essential that the internal diameter of ring 50 be substantially equal to the external diameter of ring 38. With this relationship, as brake 46 is lowered, it is possible to brake the wire 14 fed between the two rings 38 and 50 in a manner to be described hereinbelow.

In the assembled position, wire 14 is wound on cylindrical body 30 of spool 12 of this invention within machined grooves 32. Once in place wound wire 14 is held on spool 10 by any suitable cement such as an acrylic cement (not shown) lightly applied to the turns. Wire 14 is initially wound above ring 38 and continues until a proper thickness of wire is reached. At that time the end of wire 14 passes over ring 38 at point A and continues to be wound on bottom section 36 with the end of wire 14 passing over lower guide ring 42 and onto cone shaped section 40.

Wire 14 is wound above and below the brake rings 38 and 50 and is first deployed from lower section 36 of spool 10. When all the wire 14 from section 36 is deployed, a braking force is automatically applied by pulling wire 14 from upper section 34 through brake rings 38 and 50 at point A. The inner and outer rings 38 and 50, respectively, then squeeze wire 14 as it spins, thereby exerting a force to reduce wire velocity. The amount of pressure applied by brake 46 depends on the amount of space at point A regulated by the position of ring 50 with respect to ring 38. Such an adjustment takes place by the movement of brake mechanism 46 with respect to member 44.

The spinning action of wire 14 spreads the wear on the braking surfaces 38 and 50. With the instant invention braking forces in the order of 150 pounds can be achieved with a stranded cooperweld wire 14 having a breaking strength of 400 pounds. The braking force adds to the unreeling and other friction forces.

Although this invention has been described with reference to a particular embodiment it will be understood to those skilled in the art that this invention is also capable of a variety of alternate embodiments within the spirit and scope of the appended claims.

Claims

We claim:

1. A spool utilized for the deployment of wire comprising a body about which said wire is wound, said body being formed of a first and second section, means operably connected to said body for applying a braking force to said wire during unwinding thereof from said first section, said braking means being formed of a first braking ring located about said body separating said first and second sections and a second braking ring adjustably mounted on said body adjacent said first braking ring whereby said wire passes through a space formed between said first and second braking rings and means operably connected to said second section for guiding the unwinding of said wire therefrom.

2. A spool utilized for the deployment of wire as defined in claim 1 wherein said guiding means is in the form of a ring and a cone-shaped end piece.

3. A spool utilized for the deployment of wire as defined in claim 2 wherein the external diameters of said first braking ring and said guide ring are larger than the resultant diameter of the completed turns of said wire wound about said body.

4. A spool utilized for the deployment of wire as defined in claim 3 wherein the internal diameter of said second brake ring is substantially equal to the external diameter of said first brake ring.

5. A spool utilized for the deployment of wire as defined in claim 4 wherein said braking means comprises a frame which surrounds said body and is threadably attached thereto.

6. A spool utilized for the deployment of wire as defined in claim 5 wherein said body is of a cylindrical configuration.

7. A spool utilized for the deployment of wire as defined in claim 6 wherein said body has a plurality of circumferentially spaced grooves therearound.

8. A spool utilized for the deployment of wire as defined in claim 7 wherein said body has an externally threaded segment thereon for threadably engaging said frame of said braking means.

9. A spool utilized for the deployment of wire as defined in claim 8 wherein said first and second braking rings are made of smooth steel.