Highway Safety Device

Abstract

A highway safety device or barrier for decelerating and redirecting an errant vehicle as it approaches a hazard. The safety device includes a plurality of interconnected deformable metal cells containing an internal crush panel and a dispersable mass such as sand, supported on a lightweight crushable core.

Description

BACKGROUND OF THE INVENTION

In recent years, many proposals have been made to provide impact attenuators to control the rate of deceleration of an errant vehicle as it approaches a hazard such as a bridge abutment or other fixed object adjacent to a highway. One of the most successful devices is disclosed in U.S. Pat. No. 3,606,258, owned by applicant's assignee. The impact attenuator there disclosed comprises an array of frangible containers of considerable size, each containing a dispersable mass, so disposed within the container as to locate the center of gravity of the unit substantially at the level of the center of gravity of the average passenger vehicle. Barriers of this type, which are particularly effective in safely decelerating vehicles traveling at highway speeds, necessarily occupy considerable space and cannot be effectively located in restricted areas, particularly on urban streets. Also, they are essentially vehicle decelerators and are deliberately so constructed as to possess minimal vehicle redirecting capability and thus, by themselves, are not practical substitutes for guard rails and other vehicle deflecting devices.

Conventional guard rails and similar devices, although effective upon tangential impact at angles of 25.degree. or less, are extremely rigid and have little or no capacity for effecting controlled deceleration of a vehicle, when struck in line with their ends or terminals. Also, they often cause the colliding vehicle to overturn upon impact.

SUMMARY OF THE PRESENT INVENTION

It is the principal purpose and object of the present invention to provide improved vehicle deceleration and redirecting barrier devices, particularly adapted for installation in urban areas or similar locations where vehicle speeds are moderate and where available space is severely limited.

It is a further object of the present invention to provide improved barrier devices, particularly adapted for use in combination with, as a substitute for, or as a supplement to a conventional guard rail.

It is also an object of the present invention to provide improved barrier devices which are of relatively simple mechanical construction which are durable, and which are relatively inexpensive to manufacture and to install.

In attaining these and other objects, the present invention provides a barrier including a series of identical cells, preferably constructed of relatively light gauge metal and preferably cylindrical in form. The lower portion of each of the cells is filled with a lightweight, rigid, crushable core, the space above the core within the cell being filled with a dispersable mass such as sand. Preferably, the cells are constructed from half-cylinders and include a metal panel extending diametrically across the cell in a direction parallel to the path of travel of the vehicles on the adjacent roadway. The individual cells are mechanically connected together to form a mechanically continuous unit, the ends of the groups of cells being anchored by posts or connected to conventional guard rail assemblies.

Additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings.

DRAWINGS

FIG. 1 is a perspective view of a typical installation of the barrier unit of the present invention;

FIG. 2 is an exploded view of a portion of the unit of FIG. 1;

FIG. 3 is a top plan view of a portion of the barrier unit and an adjacent supporting post; and

FIG. 4 is a top plan view of the unit as it appears after impact.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a typical application of the invention in which the barrier assembly, indicated generally 10, is positioned in front of a fixed object 12, the barrier extending away from the fixed object in a direction opposite to the travel of vehicles on the adjacent roadway 14.

The barrier assembly comprises a series of identical individual cells 16 illustrated in greater detail in FIGS. 2 and 3. The cells are of elongated, cylindrical form and are fabricated from pairs of identical sheet metal half cylinders 18, each of the cylinder halves having marginal flanges 20 suitably secured together by bolts or rivets. Each of the cells also includes a crush panel 22 which extends diametrically across the cell in a direction parallel to the longitudinal axis of the barrier. The marginal edges of the crush panel extend between the flanges 20, the edges of the panel being secured by the bolts or rivets which secure the two cylinder halves together. As best shown in FIG. 3, the flanges 20 also provide a convenient means for attaching connecting strips 25 to secure adjacent cells together, essentially along their entire vertical length.

The crush panel is provided with corrugations 26 to increase the resistance of the overall cell to diametral crushing. Both the cylinder halves and the crush panel are fabricated from sheet metal, the gauge of which is sufficiently light to permit deformation upon impact by a vehicle but sufficiently heavy to assure structural integrity of the assembly and to possess the capability of energy absorption by metal deformation.

Fitted within the lower end of the cells 16 below the lower edge of the crush panel is a core assembly 28, formed from foamed polyurethane or a similar lightweight crushable plastic. Preferably the core is provided with a number of voids 30 to decrease its mass and insure its crushability upon impact. Below the main body of the core, which fits snugly within the lower end of the cylindrical call, the core is provided with an annular shoulder 32 which extends outwardly to the edge of the flanges 20.

After the units are installed, the space within the cells above the core assembly 28 is filled with a dispersable mass such as sand and the tops of the cells are closed by removable covers 34 formed of sheet metal or plastic. The covers are primarily provided to prevent the entry of moisture into the cells and at the same time improve the appearance of the units and inhibit tampering.

In a typical case, the individual cells are approximately 18 inches in diameter and 36 inches in vertical length. The core assemblies 28 are approximately 10 inches in height. The weight of the sand mass is approximately 380 pounds, giving each of the cells a total weight of approximately 440 pounds.

It is to be noted that the use of the core, which has negligible weight, elevates the center of gravity of the unit. Typically the parts are so dimensioned that the center of gravity of each of the cells is approximately 23 inches above the level of the roadway, which corresponds closely to the level of center of gravity of the average passenger vehicle. Accordingly, upon impact the barrier tends neither to raise nor depress the nose of the vehicle and thus avoids imposing an overturning moment on the vehicle, a defect associated with many prior barriers.

In the illustrated installation the barrier assembly 10 is anchored at its opposite ends to wood or metal posts 38, one of which is placed as close as possible to the fixed object 12. As best shown in FIG. 2, the cells are secured to the posts by two or more brackets 40 which encircle the posts and are suitably secured to the flanges 20 of the adjacent cell. Alternately, the barrier may be secured at one end directly to the fixed object or it may be substituted for the portion of the conventional guard rail which is normally positioned adjacent to the fixed object. Since the cells are mechanically connected to each other, the entire array of cells may form a part of a guard rail system under tension. Also the cell array may be installed in parallel with a conventional guard rail; that is, positioned alongside a conventional guard rail on the lane side where space permits. Also multiple arrays of cells may be installed side-by-side with appropriate lateral spacing to provide additional protection adjacent to wide fixed objects.

FIG. 4 illustrates the action of the barrier upon a direct head-on impact. Upon impact, the lead post 38 is broken away at ground level, the post being designed primarily to maintain the barrier in place initially. As the vehicle progresses through the barrier, the individual cells are collapsed as shown in FIG. 4 and the kinetic energy of the vehicle is gradually absorbed by metal deformation of the cell halves and the crush panel as well as by displacement or dispersement of the sand mass.

In a typical case, a five-cell barrier having an overall length of approximately 9 feet and a total weight of approximately 2,300 pounds is effective to bring a standard passenger vehicle to rest from a speed of approximately 40 miles per hour in a distance of 6 feet with an average deceleration of 9 G which minimizes damage to the vehicle and reduces injury exposure to the occupants.

It will be noted that the rigid foam core 28 not only elevates the barrier mass to the height of the center of gravity of the vehicle and thus eliminates ramping of the vehicle but also minimizes the ground level resistance to displacement of the cells which would otherwise be caused by the bearing of the cell edges against the pavement or ground surface and which might otherwise result in a dangerous vehicle ramping moment.

Instead, the core material is abraded away by friction against the ground level surface, with little resistance to the movement of the cells.

In addition to its ability to decelerate a vehicle upon straight line impact, the barrier of the present invention also has a substantial redirecting capacity and, upon low or medium angle impact, will safely direct the vehicle away from the fixed object. Unlike most guard rails or equivalent devices the redirecting force is exerted essentially at the center of gravity of the vehicle without transmitting all of said force into the ground, so that the tendency of the vehicle to ramp over the barrier or to overturn upon impact is effectively minimized.

Inherent in this barrier is a continuity of metal components extending in one plane, permitting the tensioning of the barrier, with the well-established and desirable effect of increasing its deflecting capabilities. The barrier may be joined with other tensioned barriers such as guardrail or cable barriers at any point, thus maintaining the tension uninterrupted.

In some circumstances metal cells of different diameters may be used. Larger cells of the same height may be joined in sequence with smaller cells, thus adapting the barrier to short, wide sites to good advantage.

Varying the cell diameter also permits variations in the resistance to displacement by vehicles, which would be desirable under certain circumstances.

The choice of metal as to its physical characteristics as well as its thickness or gauge provides the engineer with a useful variable for design purposes in adjusting resistance to impact.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

What is claimed and desired to be secured by Letters Patent is:

1. A highway safety device for decelerating or redirecting a vehicle approaching a hazard comprising a vertically elongated deformable hollow metal cell, a lightweight crushable core filling the lower portion of said cell and providing a ground-engaging base for said cell which permits essentially free displacement of said cell upon impact by a vehicle, and a metal crush panel extending diametrically across said cell along the full length of the portion of said cell above said core means fixedly connecting said panel to said cell, the space above said core being adapted to contain a dispersible mass such as sand.

2. The combination according to claim 1 wherein said cell is of cylindrical configuration and comprises a pair of semi-cylinders having radially projecting marginal flanges extending essentiallly the full length of said cells, said flanges being joined together, and wherein said crush panel extends between said flanges and is joined thereto.

3. A highway safety device for decelerating or redirecting a vehicle approaching a hazard comprising a group of vertically elongated deformable hollow metal cells, a lightweight crushable core filling the lower portion of each of said cells and providing a ground-engaging base for each of said cells which permits essentially free displacement of said cells upon impact by a vehicle, a metal crush panel extending diametrically across each of said cells along the full length of the portion of said cells above said core and projecting outwardly beyond the periphery of each of said cells, means including said crush panels fixedly joining said cells in alignment with adjacent cells substantially along their full length, and the space within said cells above said cores being adapted to contain a dispersible mass such as sand.

4. The combination according to claim 3 wherein the cell diameter and the cell wall thickness are varied to control the resistance of the device to vehicle impact.