Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to delimiters and particularly to retractable delimiters.
2. Description of the Prior Art
Rural airports do not generally have the types of facilities used at major airports. For example, many of these airports do not have runway lighting. The runways are marked by delimiters—cones that are placed at regular intervals along the sides of the runway. These cones are visible to pilots and enable them to see the edges of the runway. When the runway needs maintenance, e.g., when snow must be removed, the delimiters become obstacles to the cleaning process. Thus, a crew must physically remove the cones before the runway can be plowed. This may mean having a worker walk the length of the runway to move the cones. Once the snow is cleared, the cones have to be replaced. This also requires time and labor to perform.
To eliminate the need to remove cones or other delimiters, several retractable types of delimiters have been invented. These delimiters can be retracted into the ground when they are not needed and then raised when they are needed. Many of the patents for these types of delimiters are directed to highway and parking lot use. For example, large arena parking lots often need to set cones for traffic flow into the parking lot. Use of the retractable delimiters allows the parking crew to raise those units as needed to create the proper traffic flow. As time progresses and the traffic flow must be adjusted, delimiters can be raised and lowered as needed
Examples of these devices are found in the following U.S. Pat. Nos. 364,175, 3,086,430, 5,425,595 and 5,819,471.
One problem with all of these designs is that they are unsuitable for use at airports. Under aviation rules, any delimiter must collapse when struck be a wing. A freestanding cone presents no danger to an airplane. However, a rigidly installed retractable delimiter does present such a danger. These devices are not designed to flex or break when hit and can therefore cause serious damage to an airplane.
The instant invention overcomes these difficulties. It is a delimiter that can be arranged along the sides of a runway. The delimiters can be locked in an upright position for most normal operations. When the runway must be cleared of snow, an operator can lower the delimiters in place, either manually or by motor. After the runway has been cleared of snow, the delimiters can be raised again for use. Unlike the delimiters described above, these delimiters meet all aircraft regulation requirements. When collapsed, they do not protrude above the surface of the ground. The delimiters also have a shear mechanism that allows the raised portion of the delimiter to break off when struck. This shear mechanism protects aircraft by breaking away the upper portion of the delimiter.
It is an object of this invention to produce a delimiter for use at airports that can be raised and lowered quickly and easily.
It is a further object of this invention to produce a delimiter that has a breakaway capability to protect aircraft and vehicles that contact the delimiter.
It is yet a further object of the invention to produce a delimiter that can be raised and lowered by a motor.
Referring now to
Referring now to
As mentioned above, the problem with the earlier devices is that they lack any way of shearing off at ground level if they are impacted.
Referring now to
To ensure that the inner post 42 remains centered and upright in the outer case, guide rings 50 can be installed as shown. In addition to the guide rings, an upper limit system is also shown. Here, two (or more) screws 54 are secured to the lower portion of the inner post as shown. These screws contact the guide rings 50 to limit the upward movement of the inner post. The position of the screws 54 us determined by the placement of the shear point. The shear point should be places at or just above grade level. Once the proper height is determined, the screws 54 can be adjusted to ensure that the shear point is at the proper height.
The present disclosure should not be construed in any limited sense other than that limited by the scope of the claims having regard to the teachings herein and the prior art being apparent with the preferred form of the invention disclosed herein and which reveals details of structure of a preferred form necessary for a better understanding of the invention and may be subject to change by skilled persons within the scope of the invention without departing from the concept thereof.
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Number | Date | Country |
---|---|---|
492024 | Dec 1990 | EP |
2687702 | Aug 1993 | FR |