1. Field Of The Invention
The embodiments of the invention relate to a guardrail end terminal, and more particularly, to guardrail end terminal system backed by a cable.
2. Discussion Of The Related Art
In general, a guardrail end terminal system is located at the oncoming traffic ends of guardrail runs. The guardrail end terminal system is designed to deflect a side impact by a vehicle and, in the alternative, absorb a head-on or shallow angle, i.e. <5 degrees, impact by a vehicle at the guardrail extruder head at the beginning of the guard end terminal system. A guardrail extruder head absorbs energy from a head-on or shallow angle impact to its impacting head by moving down the W-beam guard rail and receiving a W-beam guardrail though a feeder chute, flattening the guardrail beam in an extruder throat by squeezing the W-shape out of the guardrail beam, and then deflecting the flattened guardrail beam through a curved deflecting plate. Thus, W-beam guardrail should feed into the guardrail extruder head and absorb energy by being flattened so as to slow an impacting vehicle as the vehicle runs down a length of W-beam guardrail while flattening the guardrail beam and deflecting the flattened guardrail. Prior art examples of such guardrail extruder heads and further description of their operation can be found in U.S. Pat. Nos. 6,715,735 and 4,928,928.
The guardrail end terminal system typically starts at the first guardrail post on which the guardrail extruder head is mounted. The guardrail end terminal system also typically includes at least second, third, fourth and fifth guardrail posts that immediately follow the first guardrail post. A guardrail is positioned within the guardrail extruder head and bolted to the second through fifth guardrail posts as well as other additional guardrail posts along the length of the guardrail. The first through fifth guardrail posts are at least included in the guardrail end terminal system in that those guardrail posts are weakened guardrail posts of the guardrail end terminal system. More particularly, weakened guardrail posts are designed to be pushed over by the guardrail extruder head as the guardrail extruder head moves down the guardrail during an impact. A guardrail end terminal system can also include sixth, seventh, eighth and ninth guardrail posts in addition to the first through fifth guardrail posts to accommodate the head-on impact of higher speed and/or heavier vehicles.
Typically, a vehicle impacting at the guardrail extruder head or impacting the guardrail between the first and second guardrail post will let the vehicle gate or pass through the guardrail end terminal system. A guardrail end terminal system should be able to deflect a high angle impact of a vehicle at a point before the fourth weakened guardrail post of the guardrail end terminal system. That is, a vehicle impacting the guardrail between the second weakened guardrail post and the last weakened guardrail post of a guardrail end terminal system should be deflected or stopped. However, the overall height of guardrail has been raised and vehicles have become heavier such that prior art guardrail end terminal systems have difficulty in deflecting or stopping a vehicle impacting the guardrail between the second and fourth guardrail posts.
Accordingly, embodiments of the invention are directed to a cable backed guardrail end terminal system that substantially obviates one or more of the problems due to limitations and disadvantages of the prior art.
An object of embodiments of the invention is to provide a cable backed guardrail end terminal system that will deflect a vehicle.
Another object of embodiments of the invention is to provide a guardrail end terminal system with a cable backing to deflect a vehicle if the vehicle impacts the guardrail anywhere between the second and fifth posts of the cable backed part of the end terminal system.
Another object of embodiments of the invention is to provide a guardrail end terminal system with a cable backing to stop a vehicle if the vehicle impacts the guardrail between the second and fifth posts of the cable backed part of the end terminal system.
Additional features and advantages of embodiments of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of embodiments of the invention. The objectives and other advantages of the embodiments of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a guardrail end terminal system includes: a first guardrail post at a first end of the system; a second guardrail post located subsequent to the first guardrail post; a guardrail extruder head mounted on the first guardrail post; a guardrail positioned in the guardrail extruder head and mounted to the second guardrail post; a first cable hanging bracket on the second guardrail post; a cable brake attached to a second end of the system opposite to the first end of the system; and a first cable anchored to the first guardrail post and extending through the first cable hanging bracket to the cable brake.
In another aspect, a guardrail end terminal system includes: a first guardrail post at a first end of the system; a second guardrail post located subsequent to the first guardrail post; a third guardrail post located subsequent to the second guardrail post; an anchor attached to the first guardrail post; a first cable hanging bracket on the second guardrail post; a second cable hanging bracket on the third guardrail post; a brake tube at a second end of the system opposite to the first end of the system; a braking slug at an end of the brake tube; and a first cable connected to the anchor and extending through the first cable hanging bracket and the second cable hanging bracket to be connected to the braking slug.
In yet another aspect, a guardrail end terminal system includes: a first guardrail post at a first end of the system; a second guardrail post located subsequent to the first guardrail post; a third guardrail post located subsequent to the second guardrail post; a fourth guardrail post at a second end of the system opposite to the first end of the system; a fifth located prior to the fourth guardrail post; an anchor attached to the first guardrail post; a first cable hanging bracket on the second guardrail post; a second cable hanging bracket on the third guardrail post; a brake bracket on the fourth and fifth guardrail posts; a brake tube attached to the brake bracket; and a braking slug at an end of the brake tube; a first cable connected to the anchor and extending through the first cable hanging bracket and the second cable hanging bracket to be connected to the braking slug.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of embodiments of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of embodiments of the invention.
Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thicknesses of layers and regions may be exaggerated for clarity.
In general, embodiments of the invention, are directed toward an improved guardrail end terminal system 1, which uses a backing cable 10 anchored 9 at the first guardrail post 2a and strung through cable hanging brackets 7 on the backs of at least the second, third, fourth and fifth guardrail posts 2b-2e so as to extend to a cable brake 8 mounted on at least a pair of guardrail posts 2j and 2k located beyond the first through fifth guardrail posts 2a-2e. For example, during an impact onto the guardrail 4 between the second guardrail post 2b and the pair of guardrail posts 2j and 2k on which the cable brake 8 is mounted, the cable brake 8 provides tension on the backing cable 10 while providing an additional length of backing cable 10 to be resistively fed behind the guardrail posts taking force from an impact on the guardrail. In this example, the backing cable 10 can slide through the hanging brackets 7 of the guardrail posts taking force from the guardrail being impacted, i.e. 2c-2e, as well as through the hanging brackets 7 of guardrail posts, i.e. 2f-2i, between the impacted guardrail posts and the cable brake 8 so as to result in an additional length cable 10 being resistively fed into the impacted portion of the guardrail 4 from the cable brake 8. In effect, the backing cable 10 together with the cable brake 8 acts as an arresting cable that provides additional support behind the guardrail posts 2b-2i at the cable hanging brackets 7 where an impact on the guardrail occurs such that the guardrail 4 will be further supported in deflecting or stopping an impacting vehicle.
The first guardrail post 2a, as shown in
The guardrail 14 is not mounted in the guardrail extruder head 16 but rather an extension of the guard rail 14 is positioned within the guardrail extruder head 16. Thus, the guardrail 14 is not attached to either the first guardrail post 12 or the guardrail extruder head 16. However, the guardrail 14 is mounted to the second guardrail post 12b and to the third through eighth guardrail posts 12c-12h through blockouts 13.
The first guardrail post 12a, as shown in
The second through eighth guardrail posts 12b-12h are yielding steel posts having an I-beam configuration with a web between two flanges. Yielding holes 23, as shown in
The anchor 19 passes through the weakening hole 12aa of the first guardrail post 12a on one side of the first guardrail post 12a and through a bearing plate 24 on the other side of the first guardrail post 12a. As the guardrail extruder head 16 moves along the guardrail 14 during a head-on or shallow angle impact on the guardrail extruder head 16, the first guardrail post 12a will be broken across the weakening hole 12aa by the guardrail extruder head such that the anchor 19 can be released. A guardrail cable 25 can also be connected to the anchor 19 and extend to a guardrail grabber 26, which is detachably attached to the guardrail 14. The guardrail grabber 26 is detachably attached in that the guardrail grabber 26 can be knocked off the guardrail 14 by the back bar 16a of the guardrail extruder head 16 as the guardrail extruder head 16 moves along the guardrail 14 during a head-on or shallow angle impact on the guardrail extruder head 16.
A yoke support 15 is position between the first and second guardrail posts 12a and 12b such the second post 12b provides support to the first post 12a and the bearing plate 24 in providing an anchor point for the anchor 19. Further, the yoke support 15 can extend to and come into contact with the bearing plate 24 at both sides of the first guardrail post 12a to provide support from the second guardrail post 12b to the bearing plate 24. In the alternative, a pair of angle iron strut supports can be used in place of the yoke 15. Thus, a first angle iron strut support can be attached at the front sides of the first and second guardrail posts 12a and 12b to provide support to the first post 12a and the bearing plate 24 in providing an anchor point for the anchor 19. Further, a second angle iron strut support can be attached at the back sides of the first and second guardrail posts 12a and 12b to provide support to the first post 12a and the bearing plate 24 in providing an anchor point for the anchor 19. Both the first and second strut supports can extend to and come into contact with the bearing plate.
The cable hanging bracket 17 can be placed on the backing cable 20 and attached to the o the back side of the second guardrail post 12b with the fastening mechanism 30. The fastening mechanism 30 includes a bolt 31 that slides through the back side of the second guardrail post 12b and a cable hanging bracket 17 as well as a spacer 32 within the cable hanging bracket 17. The spacer 32 provides a bind-free upper surface for the backing cable 20 and provides spacing for the backing cable 20 to easily slide through the cable hanging bracket 17. A washer 33 and a nut 34 on the bolt 31 secure the attachment of the cable hanging bracket 17 to the back side of the second guardrail post 12b.
Although the brake bracket 37 is shown in
As shown in
As the braking slug 40 is pulled through the rectangular-shaped brake tube due to an impact on the guardrail, the long sides 38c and 38d of the brake tube are bulged out and the short side 38a of the brake tube, positioned away from the brake bracket 37, moves toward the short side 38b of the brake tube adjacent to the brake bracket 37. The rectangular-shaped brake tube is deformed by the braking slug 40 bulging out the long sides 38c and 38d of the brake tube and collapsing the short side 38a of the rectangular-shaped brake tube toward the other short side 38b of the rectangular-shaped brake tube. The force required to cause the deformation of the rectangular-shaped brake tube as the braking slug 40 is pulled through the rectangular-shaped brake tube together with a frictional force between the braking slug 40 and the sides 38a, 38b, 38c and 38d of the brake tube as the braking slug 40 is pulled through the rectangular-shaped brake tube creates the resistive force on the braking slug 40 as the braking slug 40 is pulled through the rectangular-shaped brake tube 38. Thus, the backing cable 20, which is attached to the braking slug 40, can be resistively fed behind guardrail posts taking force from an impact on the guardrail 14 due to the resistive forces on the braking slug 40 as the braking slug 40 is pulled through the rectangular-shaped brake tube 38.
Although a disclosed embodiment of the present invention shown herein include a rectangular brake tube 38 together with a braking slug 40 having a conical portion 40a and a cylindrical portion 40, other brake tubes having other geometric shapes as well as other braking slugs having other geometric shapes are alternatively envisioned. For example, the brake tube can have a triangular shape while the braking slug has a front portion with a conical shape and a back portion with a rectangular shape. In another example, a braking slug can have a triangular wedge shape with a width less than width of rectangular brake tube but the triangular wedge shaped braking slug can have an overall height greater than the rectangular tube can. Any shape of brake tube can be used with any shape of braking slug as long as a resistive force is created by pulling the braking slug through the brake tube. The braking slug, regardless of shape, can deform, destroy or otherwise alter the shape of brake tube to create a resistive force to the braking slug being pulled through the brake tube.
It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the invention without departing from the spirit or scope of the invention. Thus, it is intended that embodiments of the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
This invention claims the benefit of U.S. Provisional Patent Application No. 61/990,139 filed on May 8, 2014, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61990139 | May 2014 | US |