US 20070201949 A1
A detectable warning plate having integrally cast lugs. The lugs may extend from the undersurface of the plate so that they can be entrapped within concrete during installation. The plate may define a vent hole through the plate above each lug to permit air to escape from beneath the dome plate during installation. The plate may include one or more integral support ribs that extend downwardly from the plate. The support ribs may extend around the plate near the periphery. The lugs may be extensions of the support ribs.
1. A warning plate to be embedded in concrete comprising:
a main body having a top surface and a bottom surface, said main body including a plurality of protrusions extending upwardly from said top surface;
a plurality of lugs extending downwardly from said bottom surface, each of said lugs defining a through-hole of sufficient size to permit free flow of concrete through said through-hole of each of said lugs; and
wherein said main body defines at least one vent hole extending through said main body from said top surface to said bottom surface adjacent to each lug, whereby air is free to vent from beneath said plate during installation of said plate in concrete.
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wherein each of said protrusions includes a planar top surface, said planar top surface of each of said protrusions being textured.
8. A detectable warning plate comprising:
a main cast body having a top surface and a bottom surface, said main cast body including a plurality of protrusions extending upwardly from said top surface;
at least one lug integrally cast with said main cast body extending downwardly from said bottom surface, said lug having an interlock segment spaced from said bottom surface a sufficient distance to permit free flow of concrete between said interlock segment and said bottom surface; and
at least one support rib integrally cast with said main cast body extending across a portion of said main cast body, said support rib extending downwardly from said bottom surface.
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15. A cast detectable warning plate to be embedded in concrete comprising:
a main body having a top surface and a bottom surface, said main body including a plurality of protrusions extending upwardly from said top surface, said protrusion being regularly space and of uniform size and shape, said main body including a support rib extending downwardly from said bottom surface, said support rib being integrally formed with said main body;
a plurality of lugs extending downwardly from said bottom surface, said lugs being integrally formed with said main body, each of said lugs defining a through-hole of sufficient size to permit free flow of wet concrete through said through-hole;
wherein said main body defines at least one vent hole extending through said main body from said top surface to said bottom surface adjacent to each through-hole, whereby air is free to escape from beneath said plate during installation of said plate in concrete.
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The present invention relates to municipal/construction castings and more particularly to detectable warning plates.
Detectable warning plates are widely used as a tactile warning for the blind in sidewalks, walkways and other similar structures. Typically, detectable warning plates are embedded in the sidewalk and have an upper surface with an arrangement of regularly-spaced protrusions in the shape of truncated domes. The size, shape and arrangements of protrusions are specified in the ADA Accessibility Guidelines for Detectable Warnings. These specifications are intended to provide uniform warnings that can be readily detected by the blind. In some applications, the prescribed pattern of protrusions is formed directly in the concrete. Unfortunately, it can be difficult to manufacture protrusions in concrete that are uniform and of consistently high quality. Further concrete protrusions are highly susceptible to wear and other damage.
Accordingly, a variety of detectable warning products have been developed to be embedded in concrete and provide the prescribed pattern of protrusions. Detectable warning plates are manufactured from materials ranging from plastic to iron. Experience has revealed that detectable warning products manufactured from plastics, composites and other relatively light materials are more susceptible to wear and more prone to damage from snow plows and other maintenance equipment. Further, conventional detectable warning products of essentially all types can be susceptible to separation from the concrete in which they are embedded. For example, external forces, such as a snow plow, may break the detectable warning plate away from the concrete. Further, the expansion and contraction associated with temperature changes can also cause a detectable warning plate to separate from the concrete. Conventional detectable warning plates have been provided with interlocking structures on their undersurface. It can, however, be difficult to get the concrete to adequately flow around the interlocking structure and these conventional efforts have met with only limited success.
Accordingly, there remains a long felt and unmet need for a detectable warning product that is durable, easily installed, remains embedded and does not warp during installation or use.
The aforementioned problems are overcome by the present invention wherein a detectable warning plate is provided with integral locking lugs. In one embodiment, the plate includes two lugs arranged in a regular pattern on the bottom of the plate. In this embodiment, each lug may extend downwardly from the undersurface of the plate and may be somewhat C-shaped. The lugs are spaced a sufficient distance from the undersurface of the plate to readily permit the flow of concrete around the lug. The plate may be cast from iron and may include lugs that are formed integral with the plate during casting.
In one embodiment, the plate may define a vent hole extending vertically through the plate above each lug. The vent holes permit air to escape from beneath the plate during installation as concrete flows in around the lugs.
In another embodiment, the plate includes support ribs to strengthen the plate and, among other things, reduce the possibility of warping or other deformation during manufacture. In one embodiment, the support ribs extend from the undersurface of the plate and extend around the plate near its periphery. In another embodiment, the support ribs are arranged in an X-shaped configuration with its intersection located at the approximate center of the plate. In these embodiments, the lugs may be extensions of the support rib.
If desired, the upper surface of the detectable warning plate may be textured to improve traction. The design and configuration of the texture may vary from application to application. For example, this texture may extend over all or a portion of each truncated dome-like protrusion, and/or over the surfaces between the protrusions.
The present invention provides a detectable warning plate that is durable and easy to install. The lugs provide an integral structure that can be embedded within concrete to provide a durable and lasting attachment. The broad spacing of the lugs permits wet concrete to easily flow around the lugs to interlock the plate and the concrete. The vent holes facilitate installation by permitting air trapped within the lugs to escape as the wet concrete flows around the lugs. Otherwise, air pockets trapped under the plate might have a significant adverse impact on the interlock between the plate and the concrete. The integral support ribs dramatically reduce the risk of warping during manufacture and may provide additional structure for the lugs.
These and other objects, advantages, and features of the invention will be readily understood and appreciated by reference to the detailed description of the current embodiment and the drawings.
A detectable warning plate in accordance with an embodiment of the present invention is shown in
Referring now to
The plate 10 may optionally include support ribs. In the illustrated embodiment, support ribs 20 a-b extend from the lower surface 18 of the main body 12 (See
As noted above, the plate 10 includes lugs 14 a-d that extend from the undersurface of the main body 12. The lugs 14 a-d may be integrally formed with the plate 10 or may be separately manufactured and attached to the plate 10. In the illustrated embodiment, the plate 10 includes four lugs 14 a-d extending from and in alignment with the support ribs 20 a-b. The lugs 14 a-d may alternatively be separate from the support ribs 20 a-b. As shown, the lugs 14 a-d of this embodiment are generally C-shaped, each having an interlock section 34 and opposite end sections 36 and 38. The end sections 36 and 38 are joined to the lower surface 18 of the main body 12. The interlock section 34 of each lug 14 a-d is spaced a sufficient distance away from the main body 12 to allow the free flow of concrete around the lugs 14 a-d during installation in wet concrete. In the illustrated embodiment, each lug is spaced approximately 33 mm from the lower surface 18. The number, size, shape, arrangement and configuration of the lugs may vary from application to application depending in large part on the characteristics of the main body 12, the characteristics of the concrete (or other foundation in which the plate 10 is to be embedded) and the desired strength of the bond between the plate 10 and the foundation.
The main body 12 may define a plurality of vent holes 40 a-d that permit air to vent from beneath the plate 10 during installation as concrete flows around the lugs 14 a-d. In the illustrated embodiment, a single vent hole 40 a-d is defined vertically through the main body 12 in alignment with the approximate center of each lug 14 a-d. As a result, the illustrated embodiment includes four vent holes 40 a-d. The number, size, shape and location of the vent holes 40 a-d may vary from application to application as desired. For example, two or more vent holes may be defined at each lug. By increasing the number of vent holes, the size of each vent hole may be decreased.
The detectable warning plate 10 may be installed in wet concrete using conventional techniques and apparatus. For example, the plate 10 may be placed in wet concrete as the sidewalk or other infrastructure is being formed. The plate 10 is placed in the concrete after the concrete has been poured and before the concrete has cured to the point where it has lost the ability to flow. The plate 10 will typically be installed so that the planar upper surface 16 of the plate 10 is aligned with the top surface of the surrounding concrete. The plate 10 is positioned with the lugs 14 a-d pushed down into the wet concrete. When placed in wet concrete, the inherent flowing nature of the wet concrete will cause the concrete to flow around the lugs 14 a-d (See
The present invention may be manufactured using any of a variety of conventional manufacturing techniques. For example, the detectable warning plate 10 may be manufactured using conventional cast iron manufacturing techniques and apparatus. In the illustrated embodiment, the plate 10 is cast as a one-piece component having integral support ribs 20 and integral lugs 12 a-d. Although plate 10 is manufactured from iron, it may alternatively be manufactured from other materials as appropriate for the specific application.
A detectable warning plate 110 in accordance with another embodiment of the present invention is shown in
Detectable warning plates 210, 310 and 410 in accordance with three additional alternative embodiments of the present invention are shown in
The above description is that of the current embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.