You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     This invention relates generally to traffic delineators, and more particularly to a handle formed in the top of a blow-molded cylindrical or conical traffic delineator. 
     The development of plastic traffic delineators, such as plastic cylinders, cones and barrels, for directing and channeling traffic flows has significantly increased the safety of automotive transportation. If a wood or metal delineator is struck by an automobile, the occupants may be seriously injured and the automobile seriously damaged. If a car being channeled by a line of plastic cylindrical delineators strikes one of the plastic cylinders, the lightweight, collapsible delineator causes little damage to the vehicle, which reduces the risk of injury to the vehicle occupants. Plastic cylinders are also sufficiently resilient to withstand numerous hits from vehicles and not show significant wear. 
     Plastic cylindrical traffic delineators have many advantages, including relative ease of manufacturing, light weight, and easy storage because the cylinders have a relatively narrow diameter and thus do not require significant space. Plastic conical traffic delineators have the same advantages and can also be stacked for storage. These delineators may be made of numerous colors, but a bright “flourescent” orange has become common. Such coloration makes the cylinders more easily seen, day or night and in good or bad weather, than other colors. 
     For ease of manufacture and use, cylindrical and conical delineators are often made in two pieces, a blow-molded cylinder or cone over which a drop down base is placed. The cylinder or cone is usually a light-weight structure having a thin, plastic wall. The drop down base may be made of lightweight plastic, but is often made of heavy rubber. Sandbags or other ballasting materials may be used to increase the weight of the base and cylinder or cone combination. 
     Recently, manufacturers have included handles on the top of the cylindrical and conical delineators to make it easier to move the delineators. One such handle is that on the cylindrical delineator being sold by Bent Manufacturing company of Huntington Beach, Calif. That handle has a modified “T” shape, with the upper surface of the handle having an arcuate curvature to fit into human hands. Another cylindrical delineator having a handle on top is depicted in U.S. Pat. No. 5,036,791 to Thurston, the disclosure of which is incorporated herein by this reference. That patent depicts two handles, one being of a generally “T” shape and the other having an inverted “U” shape. Yet another cylindrical delineator handle is that on the delineator being sold by Traffix Devices, Inc. of San Clemente, Calif. That handle is merely a reduction in the diameter of the cylinder, and then an abrupt enlargement of the diameter on the very top end of the cylinder, to form what may be termed as a “baseball bat” handle. 
     Existing handles formed on the top end of the cylinder have drawbacks. In particular, existing handles can be crushed when run over by an automobile. Generally, existing handles do not recover from such a crushing force, but rather are permanently deformed or require significant effort to push the plastic back into its original shape. Furthermore, existing handles are not as comfortable to hold as might be desired, and several of the prior handles do not accommodate attachment of a warning light or other marker to the top of the traffic delineator. 
     SUMMARY OF THE INVENTION 
     According to the present invention, handle for the top of a traffic delineator is provided that overcomes these and other drawbacks of the prior handles. A handle made according to the present invention is inexpensive to manufacture and incorporate into existing cylindrical or conical delineator designs. Thus, existing bases and molds may be used, with relatively minor modifications to incorporate the handle of the present invention. 
     The handle of the present invention includes a lower portion, and intermediate portion, and an upper portion. The lower portion seamlessly connects to the remainder of the delineator. 
     The intermediate portion is formed in the shape of a concave curve rotated about the axis of the cylindrical or conical delineator in such a fashion that the diameter of the intermediate portion gradually reduces from the lower end to the upper end. This shape renders the handle both very easily gripped by a human hand and also causes the handle to assume its original shape even after a crushing force such a car running over the handle. 
     The upper portion of the handle includes an extension beyond the reduced diameter of the intermediate section. This horizontal extension acts as a block to assist in holding the delineator by the intermediate portion. The extension may be similar to the T-shaped handles known in the art, or may be of the “baseball bat” shape. 
     The handle of the present invention may also include means for mounting a warning light to the top of the delineator. Thus, the present invention retains the advantages of prior delineator handles while providing additional advantages. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will be apparent from the following Detailed Description taken in conjunction with the accompanying Drawings, in which: 
     FIG. 1 is a perspective view of a traffic delineator cylinder having a handle according to a first embodiment of the present invention; 
     FIG. 2 is a close up perspective view of the handle depicted on the cylinder of FIG. 1; 
     FIG. 2A is a close up perspective view of the handle depicted on the cylinder of FIG. 1 that includes a hole for mounting a flag therein; 
     FIG. 3 is a top view of the handle of FIG. 2; 
     FIG. 4 is a first side view of the handle of FIG. 2; 
     FIG. 5 is a second side view of the handle of FIG. 2; 
     FIG. 6 is a cut-away bottom view of the handle of FIG. 2; 
     FIG. 7 is a perspective view of a traffic delineator cylinder having a handle according to a second embodiment of the present invention; 
     FIG. 8 is a close up perspective view of the handle depicted on the cylinder of FIG. 7; 
     FIG. 9 is a top view of the handle of FIG. 8; 
     FIG. 10 is a first side view of the handle of FIG. 8; 
     FIG. 11 is a second side view of the handle of FIG. 8; and 
     FIG. 12 is a cut-away bottom view of the handle of FIG.  8 . 
    
    
     DETAILED DESCRIPTION 
     As shown in the drawings, the present invention is embodied in a handle  10  for a traffic delineator  12 . The handle is formed into the top of a unitary cylinder  16  or cone  18  or many other delineators known in the art. The handle is formed of plastic, typically during the blow molding of the cylinder or cone. 
     The cylinder  16  or cone  18  comprises a hollow body with a central vertical axis  20  and is preferably formed by blow molding and subsequent trimming. Such delineators are known in the art. The delineator  12  may be made of many shapes and colors, including those most common in the traffic delineation industry. A plastic or rubber base  22  is often mounted on the delineator to provide ballast. Preferably the delineator is interchangeable and, where applicable, stackable, with existing cylinders or cones, and may be used with existing delineator bases. Making the delineator hollow reduces the weight and significantly reduces the amount of material needed. The delineator may be made of any of the materials known in the art, and usually includes pigments for the desired color, ultraviolet light inhibitors, stabilizers and fillers. 
     As depicted in FIGS. 1 and 2, the handle  10  comprises of a convexly curved lower portion  26 , a concavely curved intermediate portion  28 , and an upper portion  30  that includes a T-shaped grip  32 . The shape of the lower portion is preferably that of the outer surface of a toroid. That is, a cross-sectional view of the lower portion has the shape of a generally circular arc having a radius of between about one-half inch and one inch. In the three dimensional lower portion, that arc is rotated 360° about the axis  20  of the cylinder  16  to form the convexedly curved outer wall  36  of the lower portion of the handle  10 . In one embodiment, the lower portion has a radius measured from the axis of the cylinder of between about two to three inches and a vertical height of between about one-half and one inches. 
     The lower portion  26  seamlessly extends into the intermediate portion  28  of the handle  10 . The side wall  38  of the intermediate portion of the handle has the shape of a concave curve that has been rotated 360° about the axis  20  of the cylinder  16 . Although a parabolic curve, a hyperbolic curve, or other curves could be used to form the intermediate portion, Applicants have found that a generally circular curve having a radius R of between four and five inches best fits the grip of a human hand. Applicants have also found that the intermediate portion should be between about three to five inches in height. 
     The concave curve of the side wall  38  is oriented at an angle to the axis  20  of the delineator  12 . That is, the radius R of the concave curve is not perpendicular to the axis. As a result, the radius of the intermediate portion  28  about the axis of the delineator gradually reduces from between about two to three inches at bottom of the lower portion  26  to between about one to two inches at top of the intermediate portion. This reduction of the radius of the intermediate portion along the concave curvature of the side wall  38  renders the intermediate portion exceedingly easily gripped by a human hand, and it also greatly increases the strength and durability of the handle  12 . 
     As depicted in FIGS. 1-6, according to one embodiment of the present invention, the handle  10  includes curved indentations  42  cut into the side wall  38  of the intermediate portion  28 . Such indentations increase the strength of the intermediate portion. However, as depicted in FIGS. 7-12, in other embodiments of the present invention such indentations are not incorporated. 
     The upper portion  30  of the handle  10  depicted in FIGS. 1-12 has a modified “T” shape grip  32 . The “T” shape grip acts as a block so that when a hand grasps the intermediate portion  28  of the handle  10 , undercut surfaces  46  of the upper portion contact the hand to assist in lifting the delineator  12 . Also, fingers may grasp the undercut surfaces  46  to grab the handle. The crossing surface  48  on top of the handle is preferably formed with a convex arc that facilitates holding the handle in the palm of the hand. 
     As perhaps best shown in FIGS. 2 and 8, a hole  50  may be formed into the “T” shape grip  32 . Such a hole  50  is useful for mounting a light, sign, or other traffic safety device to the delineator  12 . The hole may be compression molded into the “T” shape grip, or may be cut out of the grip after molding, preferably by incorporating a divot into the mold where the hole is to be placed. As depicted in FIG. 2A, a bore  52  for accepting a flag pole may also be included on the top of the “T” shape grip. A detent  54  may be formed into the side walls  32  of the upper portion  30  for supporting the flag pole when inserted into the bore. 
     The “T” shape grip  30  may be replaced by many of the handles of the prior art. For instance, U.S. Pat. No. 5,749,673, the disclosure of which is incorporated herein by this reference, depicts a “baseball bat” style handle that may be incorporated into the present invention. Alternatively, a straight “T” shaped handle or an inverted “U” shaped handle, such as is depicted in U.S. Pat. No. 5,036,791, may be used. 
     It will be obvious to those of skill in the art that the handles depicted in the FIGURES may be modified produce different embodiments of the present invention. Thus, the present invention has several advantages over the prior art without sacrificing any of the advantages of the prior art. Although two embodiments of the invention have been illustrated and described, various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention.

Summary:
A handle for the top of a blow-molded traffic delineator includes a bulbous lower portion, an curved intermediate portion, and an upper portion that forms a T-shaped handle. The upper portion has a hole therethrough to allow mounting of a warning light or other item. The intermediate portion has a curvature that gradually reduces the diameter of the handle moving from lower end to upper end, in a shape that easily accommodates the grasp of a human hand.