US3646887A - Model rocket and shock cord retainer therefor - Google Patents

Abstract

A shock cord and retainer therefor. The shock cord retains in joined relation the nose cone and body tube of a model rocket during and after explosive separation of these parts, so that they will fall close together and be more easily recoverable. The retainer is a single piece of flexible material such as paper, to be attached inside the tube. Three holes which may be equidistant are cut into the piece of paper along its centerline. The cord is threaded through the holes with one end extending through the center hole to the top side of the paper. The cord extends along the bottom side of the paper then upward through a second hole, then around the side edge adjacent said hole, then again along the bottom surface, and finally upward through the third hole. The retainer is secured to the tube by an adhesive or bonding agent, such as glue or pressure-sensitive adhesive.

Description

United States Patent Stine 5] Mar. 7, 1972 [54] MODEL ROCKET AND SHOCK CORD RETAINER THEREFOR [72] Inventor: George H. Stine, New Canaan, Conn.

[73] Assignee: General Mills Fun Group, Inc., Minneapolis, Minn.

[22] Filed: July 30, 1970 211 Appl. No.: 59,616

[52] US. Cl ..l02/34.5, 40/21 R, 46/74 A, 102/34.l, 102/495 [51] Int. Cl ..F42b 15/00 [58] Field of Search ..46/74 A, 74 B, 74 C, 86 A, 46/86 B, 86 C; 102/341, 34.4, 34.5, 34.2, 34.3; 40/21 R [56] References Cited UNITED STATES PATENTS 2,841,084 7/1958 Carlisle ..l02/34.1 3,130,509 4/ 1964 Brooks ..40/21 R FOREIGN PATENTS OR APPLICATIONS 201,691 8/1923 GreatBritain ..........4p /2 1n 617,906 8/1935 Germany ..40/21 R Primary Examiner-F. Barry Shay Attorney-Anthony A. J uettner and Kenneth D. Ohm

[57] ABSTRACT A shock cord and retainer therefor. The shock cord retains in joined relation the nose cone and body tube of a model rocket during and after explosive separation of these parts, so that they will fall close together and be more easily recoverable. The retainer is a single piece of flexible material such as paper,

I to be attached inside the tube. Three holes which may be equidistant are cut into the piece of paper along its centerline. The cord is threaded through the holes with one end extending through the center hole to the top side of the paper. The cord extends along the bottom side of the paper then upward through a second hole, then around the side edge adjacent said hole, then again along the bottom surface, and finally upward through the third hole. The retainer is secured to the tube by an adhesive or bonding agent, such as glue or pressure-sensitive adhesive.

6 Claims, 7 Drawing Figures PATENTEDMAR 7 m2 SHEET 1 OF 2 FIE. .z

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GEORGE H. STINE /7 PAIENIEDIAR 1am 3.646.887

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gf l RECOVERY DEVICE EJECTS SLOW DESCE NT FLIGHT I COASTING ALTITUDE; 50300 F T. SPEED: 100-300 MPH BURNOUT El -J POWERED FLIGHT GENTLE LANDING INVENTOR. GEORGE H. STINE lrroawsrs MODEL ROCKET AND SHOCK CORD RETAINER THEREFOR The present invention relates to model rockets. More particularly, it pertains to a retainer for securing one end of the shock cord to the model rocket body tube.

The shock cord is usually a long piece of string, dacron or nylon and sometimes even a rubber band is used to insure that the nose cone and body tube of a model rocket will fall close together after the nose cone has been ejected from the body tube.

A number of arrangements for securing the shock cord to the model rocket body tube are currently in use. In my opinion two of these produce an unsightly and aerodynamically unclean arrangement. Another involves several gluing steps prior to installing it on the rocket tube body, while still another has been found by me to interfere with the ejection of the recovery device when such ejection is attempted.

Accordingly, one object of the present invention is to provide a shock cord retainer which can be used to secure the shock cord to the model rocket body tube without cutting or otherwise marring the outside of the rocket body tube.

Another object of the present invention is to provide a shock cord retainer for securing the shock cord to the rocket body tube which requires only one assembly and attachment operation.

Other objects and advantages of this invention will be apparent from the following description in which certain preferred embodiments of the invention are disclosed.

In the drawings which form a part of this application,

FIG. 1 is a side elevational view of a model rocket in which the present invention can be mounted;

FIG. 2 is a perspective view of the model rocket of FIG. 1 with the nose cone separated from the body tube;

FIG. 3 is an enlarged cross sectional view of a model rocket motor of the model rocket of FIG. 1 along the line 3-3 of FIG. 1;

FIG. 4 is an enlarged plane view of the shock cord retainer of the present invention;

FIG. 5 is a cross-sectional view of the shock cord retainer shown in FIG. 4 along the line 55 of FIG. 4;

FIG. 6 is an enlarged view of a portion of the body tube of the rocket shown in FIG. 1 and 2 with a portion broken away; and

FIG. 7 illustrates in a somewhat diagrammatic manner the path of a rocket, such as illustrated in FIG. 1, indicating the point at which the present invention would be useful.

In FIG. 1 the model rocket body tube 10 is formed as a compressed laminated paper tube according to conventional practice or of any other similar light-rigid and strong material. The tube I0 has four fins depicted by numeral 12 extending from its rear end. A model rocket motor or engine 14 is positioned inside the rear portion of the body tube 10. A nose cone 16 made of wood, plastic or rubber is designed to snugly fit inside of the forward end of the rocket body tube 10. The dimensions of the tube forming the body 10, the fins 12, the motor 14, and the nose cone 16 as well as the propulsion characteristics of the motor 14 are all selected with relation to each other so the model rocket will fly and the nose cone 16 will be ejected from the body tube 10 at the desired altitude. Such relationships are well known in the model rocket art as described in Handbook Of Model Rocketry by G. I-Iarry Stine published by Follett Publishing Company-copyright 1965 and 1967.

As illustrated in FIG. 2, the nose cone 16 has a ring 18 fixedly attached thereto. A shock cord 20 is tied at one end to the ring 18. The shock cord can be a long piece of string, twine, nylon, dacron or rubber. The cord 20 extends from the ring 18 and has its other end secured to the inside of the rocket body tube 10 by a shock cord retainer as more fully hereinafter described.

As shown in FIG. 3, the motor 14 has, as is well known in the model rocket art, a propulsive charge 22 compressed against a ring 24 of refractory material. The forward end of the motor is closed by a cap 26. The propulsive charge 22 is of conventional material such as black powder which will burn at any desirable rate depending upon how the powder is compacted and blended with other material. The propulsive charge 22 is fonned in three different charges or sections. A first charge 28 is provided with a compressed black powder, a second charge 30 is of a slow-buming black powder. with a slower burning rate, and a third charge 32 is a granular black powder. As is well known in the art, the first section 28 provides the initial maximum thrust to cause the rocket to obtain its desired altitude, the second charge 30 permits the rocket to coast upward to maximum possible altitude, and the third charge 32 provides the energy to cause the nose cone 16 to be ejected from the body 10.

After the nose cone 16 is ejected from or separated from the body 10, it is desirable that both of these parts come down together so that these rocket parts can be easily recovered and reassembled for another flight. The shock cord 20 insures that the nose cone l8 and body tube 10 come down together. However, the shock cord 20 cannot perform this function if it becomes detached from the body tube 10. A shock cord retainer 34 is provided to insure that such detachment does not occur.

The shock cord retaining 34 as shown in FIG. 4 is provided with three holes 36, 38 and 40 which are cut through the retainer along its centerline 42. The spacing of the holes 36, 38 and 40 is not critical, but it is advantageous to place hole 38 in the center of the retainer 34 and to place holes 36 and 40 an equal distance from hole 38. In addition, the shape of the holes 36, 38 and 40 is also not critical, but must be small enough not to permit the shock cord 20 to freely slide out of engagement with the retainer 34. The shock cord retainer 34 can be constructed of a single piece of paper, cardboard, plastic, or other material that may be affixed inside the forward end of the model rocket body tube 10 by an adhesive or bonding agent such as glue. It may be made as large or as'small as necessary to fit inside the body tube 10 and to withstand the forces exerted upon the shock cord when the nose cone 16 is ejected from the body 10.

The shock cord 20 is threaded through the shock cord retainer 34 as shown in FIG. 5. That is, one end of the shock cord 20 extends upward through the top surface of the center hole 38, with a portion thereof extending along the bottom surface of the shock cord retainer 34 upward through the hole 40, around the free edge 44 of the retainer 34 adjacent the hole 40, then along the bottom surface of the retainer 34, and finally upward through the hole 36. With the shock cord 20 threaded through the shock cord retainer 34 as illustrated in FIG. 5, the cord 20 tends to lock itself into position when tension is applied to the shock cord.

With the shock cord assembled as shown in FIG. 5, it is then secured in place on the forward interior end of the model rocket body tube 10 in some suitable manner. This securing can be accomplished by any suitable adhesive or by providing a pressure sensitive backing on the bottom surface of the shock cord retainer 34. By doing the former, one need only apply adhesive to the retainer 34 once. While doing the latter the adhesive is already applied and one need only properly position the retainer on the inside of the body tube I0. FIG. 6 illustrates the retainer 34 with the cord 20 threaded in accordance with the present invention and with the retainer 34 secured in place on the forward interior end of the model rocket body tube 10.

FIG. 7 illustrates a path of travel which a model rocket embodying the shock cord retainer 34 might well follow when flown upwardly along a substantially vertical path. After the burning of the first charge 28, such a rocket coasts to its peak altitude while the delay charge 30 is burning. Following the burnout of the delay charge 30, the third charge 32 is ignited and energy therefrom ejects or drives the nose cone 16 away from the body tube 10. As the nose cone 16 separates from the body tube I0, the shock cord 20 connecting them is subjected to shock when thenose cone reaches the maximum extension of the cord from the body. Since the shock cord 20 is attached firmly to the body tube 10 by means of the shock cord retainer 42, it insures that as the nose cone l6 and the body tube 10 descend that they will come down together with a recovery device such as a parachute or parasheet 46 as shown in FIG. 7. in view of the principles set forth herein, l have shown some of the ways of carrying out the present invention and some of the equivalents which are suggested by these disclosures.

Now, therefore, I claim:

l. A shock cord retainer for a model rocket comprising a piece of lightweight material having mutually opposed top and bottom surfaces, at least three holes therein through said surfaces. said holes being positioned along a single line with one of said holes in the approximate center of said piece, another of said holes off to one side of said one hole, and the other of said holes off to the opposite side of said one hole, a cord having one end extending upward through said center hole and threaded to extend along the bottom surface of said piece upward through said another hole, along the top surface, then around the free edge of said piece adjacent said another hole, along the bottom surface of said piece, and then upward through said other hole to the top surface of said piece, and the bottom surface of said piece being adapted to accept adhesive so said bottom surface can be readily attached to the interior surface of the body tube of a model rocket with a portion of said shock cord between said bottom and interior surfaces.

2. A shock cord retainer for a model rocket as called for in claim 1 wherein said piece of lightweight material is flexible.

ll. A shock cord retainer for a model rocket as called for in claim I wherein said holes are positioned along the centerline bf said piece.

i, A shock cord retainer for a model rocket as called for in claim 1 wherein said piece of lightweight material is flexible,

said holes are positioned along the centerline of said piece, and said another hole and said other hole are approximately equal distance from said one hole.

5. A model rocket having a body tube, a nose cone adapted for frictional engagement in the forward end of said body tube, a shock cord having one end securely fastened to the nose cone, and a shock cord retainer provided with mutually opposed top and bottom surfaces, three holes through said surfaces along a single line, a first one of said holes being in the approximate center of said retainer, a second one of said holes off to the side of said first hole, a third one of said holes off to the opposite side of said first hole, the other end of said shock cord being held by said retainer with said other end extending upward through said first hole and threaded to pass along the bottom surface of said retainer, upward through said second hole, along the top surface of said retainer, over the free edge of said retainer adjacent said second hole, along the bottom surface of said retainer, and then upward through said third hole, and means for securely bonding said retainer in place on the interior surface of said body tube with a portion of said shock cord between said bottom and interior surfaces adjacent where said body tube and said nose cone are frictionally engaged.

6. A model rocket as called for in claim 5 wherein said three holes are positioned along the centerline of said retainer, said second and third holes are approximately equal distance from said first hole, and said bonding means is adhesive between the bottom surface of said retainer and the interior surface of said body tube adjacent where said body tube and said nose are frictionally engaged.

m x c I I:

Claims (6)

1. A shock cord retainer for a model rocket comprising a piece of lightweight material having mutually opposed top and bottom surfaces, at least three holes therein through said surfaces, said holes being positioned along a single line with one of said holes in the approximate center of said piece, another of said holes off to one side of said one hole, and the other of said holes off to the opposite side of said one hole, a cord having one end extending upward through said center hole and threaded to extend along the bottom surface of said piece upward through said another hole, along the top surface, then around the free edge of said piece adjacent said another hole, along the bottom surface of said piece, and then upward through said other hole to the top surface of said piece, and the bottom surface of said piece being adapted to accept adhesive so said bottom surface can be readily attached to the interior surface of the body tube of a model rocket with a portion of said shock cord between said bottom and interior surfaces.

2. A shock cord retainer for a model rocket as called for in claim 1 wherein said piece of lightweight material is flexible.

3. A shock cord retainer for a model rocket as called for in claim 1 wherein said holes are positioned along the centerline of said piece.

4. A shock cord retainer for a model rocket as called for in claim 1 wherein said piece of lightweight material is flexible, said holes are positioned along the centerline of said piece, and said another hole and said other hole are approximately equal distance from said one hole.

5. A model rocket having a body tube, a nose cone adapted for frictional engagement in the forward end of said body tube, a shock cord having one end securely fastened to the nose cone, and a shoCk cord retainer provided with mutually opposed top and bottom surfaces, three holes through said surfaces along a single line, a first one of said holes being in the approximate center of said retainer, a second one of said holes off to the side of said first hole, a third one of said holes off to the opposite side of said first hole, the other end of said shock cord being held by said retainer with said other end extending upward through said first hole and threaded to pass along the bottom surface of said retainer, upward through said second hole, along the top surface of said retainer, over the free edge of said retainer adjacent said second hole, along the bottom surface of said retainer, and then upward through said third hole, and means for securely bonding said retainer in place on the interior surface of said body tube with a portion of said shock cord between said bottom and interior surfaces adjacent where said body tube and said nose cone are frictionally engaged.

6. A model rocket as called for in claim 5 wherein said three holes are positioned along the centerline of said retainer, said second and third holes are approximately equal distance from said first hole, and said bonding means is adhesive between the bottom surface of said retainer and the interior surface of said body tube adjacent where said body tube and said nose are frictionally engaged.

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