FIELD OF* THE INVENTION This invention pertains to vertical hanging skirt members forming part of a railroad crossing *-* ^■ gate assembly utilized for blocking the flow of traffic over a railroad crossing to prevent accidental collision with oncoming trains. More particularly, this invention pertains to a gate assembly having free-hanging skirt members which -*- ^u provide 360° reflection in darkness and an appear¬ ance of obstructing gate structure during daylight.

BACKGROUND AND PRIOR ART

The use of a deployable guard rail to block r--> traffic at a railroad crossing has long been recognized as a useful safety device to prevent collision of automobiles or other traffic with moving trains. During typical use, the guard rail or gate assembly stands in vertical position to

²³ the side of the roadway, allowing traffic to pass through when a moving train is not present. As a train approaches the railroad crossing, the gate is manually or automatically deployed to a hori¬ zontal, obstructing position, preventing the flow of traffic across the railroad tracks.

Frequently, a skirt assembly is hung from the gate arm to increase the visual appearance of obstruction and to impede improper traffic flow under or around deployed gates. The skirt assembly 0 is typically coupled at the lower side of the gate arm ^' when in its horizontal position. Skirt material includes cord or chain, either free-

O PI

hanging or interconnected along the length of the gate arm and having a length reaching close to the ground when the gate arm is fully deployed hori¬ zontally. The skirt member operates to give an appearance of a fence-like structure as it hangs from the horizontal gate arm.

Collapsible materials such as rope, cord or chain are particularly useful because they collapse to a vertical hanging structure as the gate arm is retracted to its vertical orientation. Unfortunately, this collapsible characteristic also leads to entanglement of the cord or chain, thereby interfering with normal operation of the skirt structure. Another form of skirt structure applied within the prior art includes aluminum slats or strips as individual skirt members coupled at one end to the gate arm by an eye bolt or other means of attachment which permits rotation of the aluminum slat with respect to the gate arm as it moves from horizontal to vertical position. Typical construction utilizing aluminum slats involves attachment of each slat to the gate arm at approximate 10 inch intervals. Various patterns of warning colors (red and white) are applied to the exposed surfaces of the respective slats so that the combination of slats present a recurring pattern of diagonal colors.

If the aluminum slats are permitted to hang free, entanglement may also occur, as with other prior art. Furthermore, in the wind, the slats can be turned sideways or fluttered in other

OMPI

Yklm WIPO

conductivity of aluminum increases its vulner¬ ability to formation of ice which not only interferes with the reflective properties of the skirt, but can also add excessive weight to an already heavy gate assembly.

OBJECTS AND SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a skirt member which can operate as part of a skirt assembly for a railroad crossing guard arm and which is light in weight and can be adapted with reflective tape to establish appropriate warning patterns across the width of the skirt.

It is a further object of the present inven- tion to provide skirt members for a gate assembly which may hang freely, without the need for a weighted arm to hold the members in vertical position.

It is yet another object of the present invention to provide a skirt member for utiliza¬ tion with a crossing gate assembly which provides 360 reflection uninterrupted by movement of the skirt member caused by wind.

A still further object of the present inven- tion is to provide a skirt member which is capable of breaking ice free from its reflective structure to maintain nighttime visibility.

These and other objects of the present invention are realized in a free-hanging skirt member utilized for a gate arm assembly in connec¬ tion with railroad crossing guard structure wherein the skirt member comprises a stiff,

OMPI

directions to defeat the visual obstruction objective. Therefore, a long length of aluminum metal is often attached at the lower end of each slat, tying the combination of slats together and weighting them in vertical orientation. Typically, this length of aluminum weighting material extends the full length of the gate arm as a unitary piece, tying the gate assembly into a single fence-like structure. Although the appearance of visual obstruction is provided by the slatted aluminum assembly, the numerous pieces of aluminum add substantial weight to the guard assembly, requiring greater power in the motors and lifting mechanisms for operating the system. This problem is further compounded when ice and snow are added to the weight of the aluminum.

Another disadvantage of the aluminum skirt structure relates to nighttime visibility. Typically, reflective tape is placed on each side of the aluminum slat to provide nighttime reflec¬ tion from the headlights of an automobile. If the aluminum slats are merely free-hanging, without a suspended weight attached to the bottom end of the slat, wind causes the slats to flutter sideways and to turn from their proper reflective angle.

Likewise, ice and snow build-up can block the reflective tape and defeat its nighttime function. The aluminum slats are not well adapted to release such ice and snow, particularly when they are vertically fixed between the gate arm and the suspending weight. Finally, the temperature

resilient rod having sufficient length to enable the skirt member to provide an appearance of obstruction when hanging below a gate which has been lowered to its horizontal, blocking position. The skirt member includes a top end which is adapted with rotational attachment means for coupling to the gate arm such that the rod is capable of retaining a substantial vertical orien¬ tation as the gate arm is moved from its blocking horizontal position toward the vertical non- obstructing position. A plurality of unitary, hollow or foamed, elongated plastic bulbs are positioned on the rod, essentially covering the rod surface. Each bulb has thin wall or foamed structure of three integral parts which are geometrically configured about a common axis. These include (i) a tubular body forming a midsection of the bulb and having sufficient diameter to develop the appearance of obstruction. The midsection is adapted to receive reflective material in approximate 360 implacement around the exterior surface thereof. The bulb further includes (ii) upper and lower closing surfaces which converge from the upper and lower extre- mities of the tubular midsection to form distal, coaxial stems separated from each other by a distance greater than the length of the midsec¬ tion. Each stem includes an opening positioned along the common axis of the three parts of the bulb and has an opening size adapted to fit snugly around the rod. When inserted upon the rod, adjacent stems of the bulbs are in substantial

mutual contacting position. A retaining means is coupled to the bottom end of the rod for holding the mounted bulbs in proper position on the rod.

This structure provides a lightweight skirt member which gives 360 nighttime reflection and gives the daytime appearance of a standard obstructing gate appearance. The substantial decrease in weight enables use of less expensive equipment to operate the gate crossing system. The use of the bulbs having irregular surfaces and being freely movable in the wind operates to break away any ice formation as it begins to develop around each bulb structure. The thin plastic wall or foamed structure of each bulb permits the bulb structure to partially collapse and release ice or other debris attached thereto. The use of multiple bulbs on a single rod permits the selection of various colors to form any desirable pattern to attract the attention of drivers approaching the gate crossing. An additional benefit of the present skirt member is the elimination of hanging stress on the bulbs due to total transfer of weight to the rod, which merely supports each respective bulb positioned thereon. Finally, the use of bulb structure with its rounded lateral surfaces prevent entanglement of adjacent skirt members due to movement by the wind or shifting of position as the gate arm is raised. Rather than becoming interlocked with adjacent skirt members, the round surfaces tend to merely roll off each other and keep the skirt member free to resume its vertical position when the gate arm

OMPI °ιo

is dropped to the horizontal position.

Additional benefits and objects of the subject invention will be apparent to those skilled in the art, based on the following detailed description of a preferred embodiment, in combination with attached drawings which include:

Figure 1, depicting a railroad crossing gate arm assembly with coupled skirt members in accor¬ dance with the present invention. Figure 2, showing two bulb sections mounted on a rod, the combination comprising a skirt member in accordance with the present invention.

Figure 3, illustrating a cross-section of Figure 2, taken along lines 3-3. Figure 4, showing a cross-section taken along lines 4-4.

Figure 5, depicting a bulb constructed of foamed plastic.

DESCRIPTION OF PREFERRED EMBODIMENT Figure 1 illustrates a gate arm assembly 10 having a horizontal railroad crossing guard 11 or arm adapted for displacement to a vertical, non-obstructing position (shown In broken line as item 18) with an attached combination of free- hanging skirt members 15 which are mounted at intervals of approximately 1/4 meter along the guard arm 14. A counterweight and enclosed motor

12 are ppart of the gate arm assembly 10 and are balanced on the opposite side of a pole, which also serves to support cross bars, visual alarm lighting, etc. Typically, the motor contained in the counterbalance section 12 is actuated and

-£fREX OMPI

driven by a power supply 13 which is coupled to a detector on the railroad track which registers the approach of an oncoming train. The respective skirt members 15 include a stiff, resilient, lightweight rod 30 (Figure 2) which has sufficient length to enable the skirt member to provide an appearance of obstruction as shown by item 15 in Figure 1.

Although the stiffness and resilience of the rod need not be quantitatively specified, these characteristics can be qualitatively defined in terms of function. For example, the rods must be sufficiently stiff to prevent mutual entanglement which would otherwise result from wind, vandalism, and the periodic horizontal to vertical displace¬ ment of the gate arm assembly. As can be noted in item 19 of the broken line illustration of the vertical position, the skirt members 19 are virtually touching each other. If the skirt members lack sufficient stiffness to maintain a straight, vertical line, this close contact could result in tangling of one skirt member with its adjacent ones. For example, this common problem occurs with ropes, cords, and chains where insufficient stiffness is present.

This characteristic of stiffness is to be distinguished from rigid structure which lacks flexibility. As indicated, the rod must also have resilience, which is intended to incorporate the dual characteristics of flexibility and self- restoring elasticity. These characteristics are necessary in view of frequent impacts of the skirt

fu RE c

OMPI a s _. WIPO

member against other skirt members, against vehicles and other moving objects. It is desirable that the skirt member have resilience so that following deformation of the rod around the impac- ting object, the rod is restored to its straight, stiff structure.

These characteristics of stiffness, resil¬ ience, and lightweight are present in a fiber- reinforced composite structure formed as a rod by the pultrusion process. Inasmuch as the pultrusion art is well-known, further explanation of its process is unnecessary. Other materials could likewise be utilized, including both reinforced and unreinforced thermosetting and thermoplastic materials, as well as lightweight metals which have the required resilience and durability necessary for a natural environment.

With respect to the length of the skirt member 15, it is clear that this will be dependent _. upon the height of the horizontal gate arm 14 above the ground surface. This distance is usually subject to government regulations and will vary from country to country. A length of 75 centi¬ meters is a typical length for the rod. As shown in Figure 1, the rod is attached to the gate arm at point 16 by rotational means which permits the rod to retain a substantial vertical orientation during both horizontal positioning of the gate arm and displacement thereof toward the vertical position. Such rota¬ tional means could include an eye bolt which permits the suspended rod to rotate sidewards with

respect to the eye bolt opening. This type of attachment is characteristic of prior art methods such as attachment of the aluminum slats pre¬ viously discussed. Many types of hardware attachments may be utilized to accomplish this objective.

When the subject skirt member is fully assembled as shown in Figure 1, the rod previously described is substantially concealed except for the top end including the rotational attachment means 16 and the bottom end of the rod which extends close to the ground and which includes a bolt or other retaining means to hold the elon¬ gated plastic bulbs in position along the length of the rod. The structure of such bulbs is more clearly disclosed in Figures 2, 3 and 4. Each bulb is of unitary composition, typically made by casting, blow molding or injection molding processes. The bulbs are either hollow or of foamed plastic to minimize weight and to permit deformation of wall structure upon impact, with subsequent restoration to its normal configura¬ tion.

As shown in Figure 3, the thin wall structure of the bulb is divided into three integral parts 22, 23 and 24. The central part of the bulb is a tubular body 23 whose diameter is somewhat constant as is typical of a tube shape. This tubular body 23 forms the midsection of the bulb and is configured in size to provide the desired appearance of obstruction for deterring vehicle passage underneath the gate arm 11. A

typical bulb diameter may range from approximately five to ten centimeters, with the preferred width being approximately 7.5 centimeters. This tubular midsection 23 is also adapted to receive reflec- tive material in approximate 360° implacement at its exterior surface. This can be accomplished by applying reflective tape 37 around the central part of the midsection 23 at its exterior surface 36. It will be noted in the figures that surface 36 in the tubular midsection 23 is slightly recessed, developing a ridge 35 at upper and lower sides of the surface area 36. This recess functions to protect reflective material which is adhered at surface 36 from contact abrasion. Bulb 20 in Figure 2 (shown in cross— section in Figure 3) is illustrated without reflective material to give clear view of the recessed surface 36. Bulb 21, on the right side of Figure 2, specifically shows the reflective material mounted at the midsection. Because this material wraps around the full structure of the bulb, 360 of light reflection is provided. This represents a distinct advantage over the prior art aluminum slats which were flat and would tend to flutter in and out of reflective position in response to the wind or other causes of vibration. The remaining two parts of the thin wall plastic bulb comprise the upper 22 and lower 24 closing surfaces which converge from the terminal extremities of the midsection 23 to form distal, coaxial stems 26 and 27 which are utilized, to

position the bulb on the rod 30. As noted in the figures, the distance between the respective stems 26 and 27 is greater than the distance of the tubular midsection. Each stem extends beyond the end of the tubular midsection to provide a taper¬ ing wall 22 and 24 which helps to provide resilience to the thin structure and also facilitates collapse with minimal force to assist in breaking away ^* ice adhering to the curved surfaces. This structure provides other beneficial characteristics which are inherently realized by a bulb configuration.

The segmentation of the bulb into three sections is not, however, to be construed as a strict definition of three separate . structured parts. To the contrary, the bulb is a single, unitary structure. The segmentation is done primarily for the purpose of distinguishing the tubular section of the bulb, which provides surface for reflective tape from the remaining two parts at the top and bottom of the tubular section which are required to close the bulb and provide support to the tubular portion. Accordingly, dimensions are not critical with respect to the three segments. Typically, the requirement for maximum reflectivity will dictate that the tubular midsection will be larger than the remaining upper and lower closing surfaces.

The figures illustrate the desired symmetry which results from the construction of these three integral parts of the bulb about a common axis 40. Typically, this axis will, be

defined by the center of the supporting rod 30, which operates as the mount for each of the bulbs. This is accomplished by use of openings within each stem which likewise retain a coaxial orienta- tion with the bulb structure about axis 40. The opening size is approximately equal to the dia¬ meter of the rod to ensure a snug fit as the bulb is positioned on the rod. When properly posi¬ tioned, the adjacent stems of each pair of bulbs (i.e., 27 and 28) are in substantial mutual contacting position to cover all but the top and bottom ends of the rod. It will be noted that remaining bulbs on rod 30 in Figure 2 have not been included because of their similarity with those bulbs illustrated, 20 and 21. The actual number of bulbs used in connection with the skirt member will depend upon bulb size and the length of rod to be attached to the gate arm.

As an alternative to collapsible thin wall structure, a bulb of foamed plastic can be utilized. This embodiment is shown in Figure 5. The characteristic bulb configuration is applied in accordance with the three geometric sections previously described. The bulb interior has a foamed content 50 which retains the collapsible, resilient properties of the hollow bulb. The exterior, skin surface 51 is smooth and weather- resistant.

The subject bulbs are constructed of thermoplastics which are capable of enduring the adverse effects of the environment, such as sunlight, cold temperatures, etc. EVA has been

OMPI

found to be a suitable material for construction of the subject bulbs and provides a collapsible, thin wall which is effective in maintaining low weight and breaking ice from its exterior surface, while at the same time providing sufficient resilience to maintain the bulb in its normal configuration in the absence of impacting forces. HYTRIL (tm) and similar good weathering plastics provide suitable properties for bulb construction in accordance with the present invention. Foamed bulbs would likewise be fabricated from similar weather-resistant plastics by well-known techniques.

As previously indicated, the dimensions of the bulbs will vary greatly, depending upon the length of the rod, the desired reflective pattern, and the pattern of bulb colors which may be varied. It should be noted that a distinct advan¬ tage of utilizing a plurality of plastic bulbs permits selection of different colors which may be utilized to increase the visibility of the skirt structure for the gate assembly. These bulb patterns can be ordered to create diagonal stripes traversing across the several skirt members in numerous patterns. These color variations can be complimented with several colors of reflective tape to further increase skirt visibility.

Because of the desirability of having several bulbs mounted on each respective hanging rod, bulb length will typically range from 7 centimeters to approximately 45 centimeters. The tubular section of the bulbs will typically range

from 25 percent to 85 percent of the total bulb length. Most of this surface area will be adapted for implacement of reflective material. The afore¬ mentioned recess area offers protection against abrasive contact for such reflective material and will typically be at least one millimeter in depth. The dimensions of the bulbs illustrated in the figures are approximately 15 centimeters in length with approximately 60 percent of the length comprising the tubular midsection and approxi¬ mately 7.6 centimeters of the midsection being recessed for reflective tape. Utilizing these dimensions, each bulb may be viewed from 360 orientation with the appearance of a 7.6 centi- meter square.

Although the respective skirt members function adequately without additional weight at the base of the skirt, Figure 1 illustrates the addition of weighted material attached at the bottom end 17 of each of the respective skirt members. This weighted material may be a board, chain or length of plastic to assist in retaining the skirt members in relative parallel orienta¬ tion. As with the rotational means of attachment at the top end, similar rotational means are required at the bottom end to enable each respec¬ tive skirt member to retain its substantially vertical orientation during displacement from the horizontal blocking position of the gate arm to a vertical, non-obstructing position as illustrated in dashed lines in Figure 1.

It is to be understood that the subject

OMPI

disclosure relates to the preferred embodiment and should not be construed as limiting the following claims, which define the invention.

OMPI