US3774540A

US3774540A - Terradynamic brake

Info

Publication number: US3774540A
Application number: US00203564A
Authority: US
Inventors: M Burford; R Simpson; R Bernardin
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1971-12-01
Filing date: 1971-12-01
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

A terradynamic brake of tubular configuration adapted to be attached around a projectile-like package which is to be air dropped or otherwise launched and operable to deploy upon striking the ground whereby penetration of the earth is limited. The brake has series of slots aligned with each other. The slots are parallel to the axis of the tube. The forward-most of each series extends from the forward edge of the brake. Upon earth impact, the arch-like portions of brake located between the forward-most slots are bent outward to approximately right angles to the brake axis.

Description

United States Patent 1 1 Burford et al. Nov. 27, 1973 TERRADYNAMIC BRAKE 3,282,216 11/1966 Calfee at al .1 mm x [75] Inventors: Milton K. Burford, China Lake,

Calif; Robert A Si M d; Primary Examiner-Samuel W. Engle Rodney A. Bernardin, Wayzata, Att0rneyR. S. Sciascia et a1. both of Minn.

[73] Assignee: The United States of America, as [5 7] ABSTRACT tg by the secretary of the A terradynamic brake of tubular configuration adapty ed to be attached around a projectile-like package [22] Filed: Dec. 1,4971 which is to be air dropped or otherwise launched and operable to deploy upon striking the ground whereby [2]] Appl' 203564 penetration of the earth is limited. The brake has series of slots aligned with each other. The slots are par- [52] US. Cl 102/2, 102/7.4, 102/53, allel to the axis of the tube. The forward-most of each 188/1 C series extends from the forward edge of the brake. [51] Int. Cl. F42b 25/00 Upon earth impact, the arch-like portions of brake lo- [58] Field of Search 102/4, 2, 7.4, 52, cated between the forward-most slots are bent out- 102/53, 54, 7.2; 188/1 C ward to approximately right angles to the brake axis.

[56] Reerences Cited 1 Claim, 3 Drawing Figures UNITED STATES PATENTS 2,667,838 2/1954 Cook 102/8 X 1,237,012 8/1917 Barlow 102/7.2

TERRADYNAMIC BRAKE BACKGROUND OF THE INVENTION The present invention relates to braking devices and, more particularly, to one-shot braking devices for controlling or limiting the penetration into the ground of air-dropped or launched packages.

Problems have arisen in the past where packages have been dropped into sandy-like soil. As the package penetrates the earth it forms a conical hole causing the brake to be partially or totally inefective, since the brake is unable to sufficiently contact the sidewalls of the conical hole. The present invention is attached to the package as near the forward edge of the package as possible so that the expanded brake can reach the side walls of the conical impression formed by the penetration of the package.

SUMMARY OF THE INVENTION The present invention is a one-shot braking device which is adapted to be secured to a package which is to be air-dropped. The device is cylindrical and has slots extending from its front edge. Upon impact with the earth, the portions of the braking device between the slots will bend outwardly resulting in increased frontal area of the package which results in a greater drag or decelleration force on the package.

The present invention is attached to the package as near the forward edge of the package as is practicable so that the expanded brake can reach the side walls of the conical impression formed when the package impacts the soil.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows the invention as it is attached to the package;

FIG. 2 is a plan cross section taken in the direction The invention is a thin walled cylinder 10 of steel or sheet of thin metal and is wrapped around the nose of a package 11. The forward edge of the brake is located so that it is on the same plane as the forward surface of the major diameter of the package nose.

A series of slots 12 extending from the front edge of the brake form a series of tabs 13 which bend outwardly upon impact with the soil causing an increase in the frontal area of the package and resulting in a greater drag. This prevents the package from being buried in the soil. Additional axial slots 14 are colinear with slots 12. These additional holes allow the tabs to become longer as the middle portion between the holes is torn away when the package impacts the soil at very great speeds.

What is claimed is:

l. A projectile brake for use with an air dropped package comprising in combination:

a cylindrical projectile nose having a necked down portion at one end forming a cylindrical protrusion extending from the center of said projectile nose;

a thin walled cylinder superimposed and rigidly attached to the outer surface of said projectile nose;

said thin walled cylinder having its forward edge coplanar with the surface of the necked down portion of said projectile nose;

plurality of rectangular finger-like projections formed as an integral part of said thin walled cylinder with each of said finger-like projections spaced from each other by a series of spaced aligned slots;

plurality of arcuate portions of said thin walled cylinder separating each of the series of spaced aligned slots for forming a number of yieldable members;

whereby the cylindrical protrusion extending from the center of the said projectile nose forms a conical cavity upon impact with the earth causing the said finger-like projections to engage the walls of the conical cavity to bend outwardly to shear the arcuate portions of the thin walled cylinder as progressively harderearth is met for applying a variable braking force to the air dropped package for limiting depth of penetration into the earth.

Claims

1. A projectile brake for use with an air dropped package comprising in combination: A CYLINDRICAL PROJECTILE NOSE HAVING A NECKED DOWN PORTION AT ONE END FORMING A CYLINDRICAL PROTRUSION EXTENDING FROM THE CENTER OF SAID PROJECTILE NOSE; A THIN WALLED CYLINDER SUPERIMPOSED AND RIGIDLY ATTACHED TO THE OUTER SURFACE OF SAID PROJECTILE NOSE; SAID THIN WALLED CYLINDER HAVING ITS FORWARD EDGE COPLANAR WITH THE SURFACE OF THE NECKED DOWN PORTION OF SAID PROJECTILE NOSE; PLURALITY OF RECTANGULAR FINGER-LIKE PROJECTIONS FORMED AS AN INTEGRAL PART OF SAID THIN WALLED CYLINDER WITH EACH OF SAID FINGER-LIKE PROJECTIONS SPACED FROM EACH OTHER BY A SERIES OF SPACED ALIGNED SLOTS; PLURALITY OF ARCUATE PORTIONS OF SAID THIN WALLED CYLINDER SEPARATING EACH OF THE SERIES OF SPACED ALIGNED SLOTS FOR FORMING A NUMBER OF YIELDABLE MEMBERS; WHEREBY THE CYLINDRICAL PROTRUSION EXTENDING FROM THE CENTER OF THE SAID PROJECTILE NOSE FORMS A CONICAL CAVITY UPON IMPACT WITH THE EARTH CAUSING THE SAID FINGER-LIKE PROJECTIONS TO ENGAGE THE WALLS OF THE CONICAL CAVITY TO BEND OUTWARDLY TO SHEAR THE ARCUATE PORTIONS OF THE THIN WALLED CYLINDER AS PROGRESSIVELY HARDER EARTH IS MET FOR APPLYING A VARIABLE BRAKING FORCE TO THE AIR DROPPED PACKAGE FOR LIMITING DEPTH OF PENETRATION INTO THE EARTH.