Abstract:
A flexible gate is disclosed which comprises a plurality of segments. The segments may be connected by at least one coupling. When the flexible gate is acted on by a force, the flexible gate may flex. When the force is no longer present, the flexible gate may return to a substantially straight position. The segments may be removed or added as needed to repair broken segments or to adjust the length of the flexible gate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 60/136,254 filed May 27, 1999. Said U.S. Provisional Application Ser. No. 60/136,254 is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the field of crossing gates and more particularly to the field of railroad crossing gates. 
     BACKGROUND OF THE INVENTION 
     Known to the art are solid, one piece gates to prevent traffic from crossing a certain area. For example, railroad crossing gates are lowered when a train is approaching to prevent traffic from crossing the railroad tracks. In another example, a gate may be used to prevent vehicles from entering a parking lot unless the customer pays a fee. 
     Typically, a motor is used to raise and lower a gate to stop traffic and to allow traffic to pass. However, a large motor may not be feasible for raising and lowering gates due to cost and physical size limitations. Thus, smaller motors are typically utilized with solid, light-weight gates that may be resistant to outdoor elements. For example, a number of gates are made of a solid piece of lumber, however fiberglass and aluminum have also been utilized. Unfortunately, gates made out of lumber, fiberglass, and aluminum known to the art are susceptible to damage if they come into contact with a vehicle. 
     Installing and maintaining a gate which is made of one solid member presents a number of problems. First of all, some gates need to be very long. For example, present highway railroad crossing gates may be as long as forty feet. Since different crossings require a different lengths of gates, a variety of sizes must be kept on hand to replace damaged gates. It may be costly to keep different sizes of gates. Additionally, it may present a storage problem due to the length of the gates. Special carriers must be installed on maintenance vehicles in order to transport gates. In order to accommodate this difficulty, some gates have been produced with two pieces of tube that telescope one inside the other. This may provide some flexibility in gate length, but results in added weight and makes it difficult to install, especially with just one maintenance person. 
     Damage caused when vehicles strike the gates is another problem with gates known to the art. Vehicles often strike crossing gates, usually unintentionally. Another example may involve crossing arms that are sheared off when they come down between the cab and the trailer of semi trucks. Damage to the gates costs railroad companies millions of dollars in material costs and labor costs. Also, when the gates are non-functional, the intersections become extremely dangerous for the public. For example, if a railroad crossing gate is not functional, a motorist may be unaware that a train is approaching a railroad crossing and may proceed through the intersection and subject themselves to a risk of an accident which could be prevented if the crossing gate is operational. 
     Some existing gates have been designed with shear pins so that the whole gate falls off when struck. While the repair person will still have to remount the crossing arm, sometimes it will not be damaged beyond use. However, the crossing arms may be run over and broken by vehicles and trains. 
     Consequently, it would be advantageous to provide a gate which is light-weight, capable of length adjustment, may be installed easily by a single maintenance person, and may not be damaged when vehicles inadvertently strike the gate. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a gate in which its length may be adjusted and one which may not be completely damaged if struck by a vehicle. Additionally, the present invention is directed to a gate which has the capability of being installed by a single maintenance person. The flexible gate of the present invention comprises a plurality of segments which may be connected by a coupling between the segments. The flexible gate may flex when acted on by a force and return to a normal straight position when the force is no longer present. 
     Segments may be added or removed to a gate in order to increase the length of the gate or decrease the length of the gate. Since the segments are fairly short, the segments may be carried and stored easily, and allow for easy installation or repair by a single maintenance person. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The numerous objects and advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
     FIG. 1 is an illustration of an exemplary embodiment of a flexible gate of the present invention; 
     FIG. 2 is an illustration of an exemplary embodiment of a flexible gate of the present invention displaying flexible movement of the gate; 
     FIG. 3 is a cut-away view of an exemplary embodiment of a flexible gate; 
     FIG. 4 illustrates an exemplary embodiment of a base segment of a flexible gate; 
     FIG. 5 is a cut-away view from the top of an exemplary base segment of a flexible gate; 
     FIG. 6 is a cut-away side view of an exemplary embodiment of a segment with an endcap with an attached spring and spring mounting bracket; 
     FIG. 7A is a top cut-away view of an exemplary embodiment of a flex joint; 
     FIG. 7B is a side cut-away view of an exemplary embodiment of FIG. 7A; 
     FIG. 7C is a front view of an exemplary embodiment of a flex joint which illustrates a slot in which the cable passes in an exemplary embodiment; 
     FIG. 8 is an illustration depicting a detailed cut-away of an exemplary embodiment of a flex joint between two gate segments; and 
     FIG. 9 is a detailed cut-away of an exemplary embodiment of a flex joint between two gate segments while the gate is in the bent position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to a presently preferred embodiment of the invention, examples of which are illustrated in the accompanying drawings. 
     Referring now to FIG. 1, an exemplary embodiment of a flexible gate  100  in accordance with the present invention is shown. The flexible gate  100  comprises a plurality of segments  110  connected to each other by flex joints  116 . A base segment  112  may be utilized at the side of the gate that may be attached to the mechanism used for raising and lowering the gate. The base segment  112  may be attached to a gate support  142  via a bracket  140 . 
     In an exemplary embodiment, the segments may be tubes with a rectangular cross section constructed of fiberglass, aluminum or other durable material. It should be apparent to a person of ordinary skill in the art that other cross sections may be utilized for the segments as an alternative to a rectangular cross section. In a preferred embodiment, the segments may be between three feet and five feet in length. Shorter segments may be easier to store and carry than full-length gates. Additionally, different length gates may be easily constructed by using the proper number of segments. Furthermore, if a segment is damaged, the gate may be repaired by removing and replacing the damaged segment. It may be preferable to form segments in a uniform size to aid in repair and replacement. Therefore, a repair crew may carry a fewer number of segments. 
     Another advantage of the present invention is the capability to withstand damage if the gate is struck. Referring to FIG. 2, an illustration of an exemplary embodiment of a gate as shown in FIG. 1 is shown displaying the capability of the gate to flexibly move in accordance with the present invention. In a preferred embodiment, a vehicle strikes a gate which may cause the gate to flex, and then return to a normal position without damaging the gate. With this embodiment, the gate may remain functional and may ensure that a railroad crossing has an adequate system to prevent traffic from crossing railroad tracks when a train is approaching. 
     Referring to FIG. 3, an exemplary embodiment is shown wherein segments may be held in place by stringing a tension cable  118  from a base segment  112  to a spring  122  which is attached to an endcap  114  of a final segment via a connecting device  120 . A close-up view of an exemplary base segment is shown in FIG.  4 . Tension may be applied to the cable  118  by turning a hex nut  128  that is connected to the ratchet wheel  124  using a torque wrench. The pawl  126  pivots about the hinge pin  132  and prevents the ratchet wheel  124  from loosening by rotating backwards. The pawl  126  may be locked into place by inserting a bolt  130  through a hole in the pawl  126  into a threaded hole in the base segment  112 . 
     A cut-away view from the top of an exemplary base segment is shown in FIG.  5 . The tension cable  118  may be passed through a slot  150  in the flex joint  116  and then through a hole in the reel  134 . One end of the reel  134  passes through a hole in the base segment  112  and is attached to the ratchet wheel  124 . The other end of the reel  134  is connected to a threaded rod  136  that passes through the other side of the base segment  112  and has a nut  138  threaded onto the rod  136 . By turning the ratchet wheel  124 , the reel  134  is turned in the same direction. 
     Referring to FIG. 6, a cut-away view of an exemplary final segment is shown. In this embodiment, the end of the tension cable  118  may be attached to a spring  122 . The spring  122  is attached to a connecting device  120  which is attached to an endcap  114  of the final segment. It should be apparent that the spring  122  may be placed anywhere in the gate without departing from the spirit and scope of the present invention. 
     Turning to a more thorough explanation of an exemplary embodiment of a flex joint, cut-away views of the flex joints are shown in FIGS. 7A,  7 B, and  7 C. Cable  118  is passed through the slot  150  of the flex joint  116  and held centered by the inside curve  152  of the flex joint  116 . Referring now to FIG. 8, a detailed view of an exemplary embodiment of the gate of the present invention in a non-flexed position is shown. When the segments  110  are pivoted about the barrier surfaces of  154  of the flex joint  110 , an increase in the tension of the cable  118  results and the spring  122  is stretched as shown in FIG.  9 . The surfaces  156  of the flex joint  110  may be curved on a radius such that they keep the segments  110  aligned with each other. 
     The tension in the cable  118  may cause the segments  110  to return to their normal straight position after bending pressure is removed. A one-way shock absorber (not shown) may be mounted in parallel with the spring to prevent the gate from swinging back too quickly after it has been bent. In another embodiment, by utilizing a different thickness and inside curvature  152  of the flex joint  110 , the flexibility characteristics of the joints may be varied. For example, easily flexing joints may be used on the free end of the gate which has to support less weight and survive less wind pressure than joints at the base end of the gate. 
     It is believed that the present invention and many of its attendant advantages may be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.