Injection-molded plastic nestable shell for concrete parking bumpers

A parking bumper shell that can be easily filled with a heavy form-filling material (such as concrete) to form a parking bumper is provided. The parking bumper shell may be injection molded from durable, brightly-colored, UV- and weather-resistant plastic. Undercuts, such as in the form of a plurality of undercut wings or z-puller pins, may be disposed on the interior of the parking bumper shell's top and side walls to aid in holding the parking bumper shell and the heavy filling material together. The parking bumper shell may also include internally projecting hollow extensions that are adapted to receive anchoring posts. While the parking bumper shell is being filled, it may be placed in a rigid frame which helps the shell to keep its shape during filling. The parking bumper shells are light-weight, nestable, and do not require internal steel rebar reinforcement, thereby greatly reducing transportation costs.

FIELD OF THE DISCLOSURE

This disclosure relates generally to parking bumper shells for use in making parking bumpers for a parking lot, and, more particularly, to a parking bumper shell that can be easily transported and filled to create a parking bumper.

BACKGROUND

Typically, parking bumpers are made primarily of concrete with internal, axially-extending steel reinforcing bar (rebar) reinforcement and have a generally trapezoidal cross-section or half-octagonal cross-section. Parking bumpers are usually held in place with respect to a parking space or otherwise by gravity, as well as through the use of rebar or other inexpensive metal rods which anchor the parking bumper to the parking lot surface. Mating channels may be provided through the parking bumper with sufficient clearance to allow a length of rebar or a similar metal rod to pass through the parking bumper. Typically, the parking bumper is positioned in the parking lot, and then anchoring posts are driven through the mating channels into the parking lot surface to secure the parking bumper. The parking bumper may be moved to a desired location on a concrete, asphalt, or otherwise paved surface using, for example, front end loaders, cranes, or other common hauling or moving equipment.

Parking bumpers may sometimes be painted. For example, parking bumpers are often painted yellow. Additionally, parking bumpers may be painted with lettering to designate the characteristic of the parking spot, such as the parking spot being for “visitors” or “handicapped”. Painting and labeling, of course, require extra materials and labor.

It is difficult and expensive to transport concrete parking bumpers, as described above, to a given parking lot location. Moreover, the paint or lettering on parking bumpers fades and chips away quickly. As a result, painted bumpers require frequent maintenance. Another drawback of conventional concrete parking bumpers is their vulnerability to the outdoor elements. The freeze-thaw cycle and road salt, particularly in colder climates with snowy and icy winters, degrade concrete parking bumpers, causing them to crack, crumble, chip, or undesirably crush when impacted by a car tire.

The parking bumper shells of the present disclosure overcome these and other shortcomings of conventional concrete parking bumpers. As compared to conventional parking bumpers, the parking bumper shells of the present disclosure are inexpensive to produce, light-weight, and take up less cargo space when nested. Moreover, the parking bumper shells can be formed using material that is already of the desired color, for example, yellow plastic, and preferably, UV stabilized. Thus, the need to continually maintain and paint the parking bumper is eliminated.

SUMMARY OF THE DISCLOSURE

The parking bumper shells of the present disclosure are preferably made of injection molded plastic and include a top wall, first and second side walls, and first and second end walls. Preferably, the parking bumper shells are formed such that they have a cross-sectional shape of a half-octagon. Accordingly, each of the first and second side walls preferably has a first portion that is outwardly tapered and a second portion that extends vertically from a bottom of the first portion.

A lip may extend substantially along each of the first and second side walls to aid in keeping the filling material within the parking bumper shell and to provide a surface upon which to level the filling material after it is poured. The lip may be located at a bottom edge of the side walls and extends inwardly approximately ¼ inch from the side wall.

Internal ribs that extend substantially along the length of the side walls may also be provided on an interior of the first and second side walls. Like the lip, the internal ribs aid in keeping the filling material within the parking bumper shell. The internal ribs project inwardly approximately ¼ inch from the first and second side walls. The internal ribs may be spaced evenly along a height of the side wall.

The top wall may include inwardly projecting elongate knock-out pins. Each of the elongate knock-out pins may aid in keeping the filling material within the parking bumper shell by having an undercut along a portion of the length of the pin, into which the concrete, or other heavy, hardenable filling material, may creep. A portion of the elongate knock-out pins has a reduced thickness, thereby providing a notch or detent to retain the heavy filling material therein, and provide resistance to maintain the heavy filling material within the parking bumper shell. These knock-out pins are referred to herein as “z-puller pins,” due to the cross-sectional appearance of the pins and a preferable shape of the detents therein, although it will be understood that different profiles or detent shapes than those shown in the accompanying drawings (e.g. sawtoothed, stair-step, wave-formed, etc.) may be employed without departing from the scope of the present disclosure and appended claims. The z-puller pins are thus elongate knock-out pins wherein a portion of the elongate knock-out pin has a thickness that reduces at a constant rate, to form a z-shaped notch or detent in the pin. The pins may be supported by one or more ribs, or instead by an enlarged base section, which help anchor the z-puller pin to the wall on which it is attached. In a preferred embodiment, a plurality of z-puller pins are provided in the parking bumper shell on the underside of the top wall.

The top wall may further include internally projecting hollow extensions. The hollow extensions may be conical, and include a ledge and a shoulder to allow for proper seating of a washer, an anchoring post, and a cap within a top portion of the hollow extension. Each of the hollow extensions may be further provided with a neck and inwardly projecting fins. The neck and inwardly projecting fins may be disposed at a lower portion of the hollow extension and can aid in securing the anchoring post within the hollow extension. The inwardly projecting fins may be oriented to form a keyway, which allows a lifting tool with an L- or T-shaped extension to be inserted to assist in moving the filled parking bumper. The conical hollow extensions may each include at least one annular bead on an exterior thereof. Like the notch or detent in the z-puller pin, and the internal ribs, the annular bead serves to retain concrete or other heavy form-setting material in the parking bumper shell.

A parking bumper of the present disclosure may be formed using one of the parking bumper shells of this disclosure. To form a parking bumper, the parking bumper shell may be inverted and filled with any suitable form-setting heavy filling material, for example, concrete. The filling material may be leveled using the bottom peripheral edge of the side and end walls as a guide for a trowel or similar leveling tool.

Because the weight of the filling material may cause the first and second walls of the parking bumper shell to bow outward during filling, resulting in a parking bumper with sides that are not parallel, planar and square, a removable rigid casting frame may be used to support the parking bumper shell during filling of the parking bumper shell and curing of the heavy filling material within. Before filling, the parking bumper shell is inverted and lowered into the rigid frame. The rigid frame is sized just large enough to allow the parking bumper shell to slide into place within the frame. Heavy filling material is then poured into the parking bumper shell, and the filler material is leveled (using a trowel or similar straight-edged tool) with the top of the rigid frame. The side walls of the rigid frame may be of a height equal to that of the parking bumper shell within, or preferably, may be slightly higher, such that the completed parking bumper sits atop a thin base pad of additional filler material. The base pad embeds the bottom peripheral free edge of the parking bumper shell's end walls and side walls in filler material.

Once the filling material is solidified, the parking bumper is turned upright and properly positioned on the parking lot surface. When the parking bumper is placed upright for installation, the base pad (if provided) elevates the plastic shell off the ground slightly to prevent damage to the plastic parking bumper shell as the completed parking bumper is maneuvered into place. Finally, anchoring posts may be driven through the hollow extensions and into the parking lot surface to permanently hold the parking bumper in place.

Parking bumpers formed using the parking bumper shells of the present disclosure are virtually impervious to typical outdoor elements, such as the freeze-thaw cycle, and resistant to degradation even after long exposure to road salt. When formed of injection molded UV stabilized plastic, the parking bumper shells of the present disclosure also advantageously retain their bright color for many years, even after constant exposure to direct sunlight.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Provided is a parking bumper shell and method of making parking bumpers using the parking bumper shell. The parking bumper shell may be formed from any suitable material. For example, the parking bumper shell may be formed from a plastic. Preferably, the parking bumper shell is formed using injection molded plastic, and most preferably, injection molded UV stabilized plastic. The parking bumper shell may be painted or formed from a dyed material. For example, the parking bumper shell may be formed using a plastic with a yellow color.

Referring toFIG. 1, the parking bumper shell10has a height H, width W, and a length L. The length L of the parking bumper shell10may be greater than the height H of the parking bumper shell10. Preferably, the length L is either three feet or 6 feet. A cross-section of the parking bumper shell10may be, for example, a semi-circle, a trapezoid, or any other suitable shape. Preferably, as shown inFIG. 1, the parking bumper shell10has a half-octagonal cross-sectional shape.

The parking bumper shell10has a top wall14. First and second side walls12are operatively coupled to, and respectively extend from, opposite sides of the top wall14. First and second end walls16, having a shape that substantially corresponds to the cross-sectional shape of the parking bumper shell10, are operatively coupled to and extend from opposite sides of the top wall14. The first and second end walls16connect adjacent ends of the respective first and second side walls12, so as to form an open-bottom chamber. The side walls12of the parking bumper shell10may be substantially planar. Preferably, the first and second side wall12, the top wall14, and the first and second end walls16are approximately ⅛ inch thick.

The first and second side walls12may each include an outwardly tapered first portion12aand a generally vertical second portion12b. Preferably, the outwardly tapered first portion12amay be disposed above the generally vertical second portion12b.

Referring toFIG. 2, the first and second side walls12may each include an inwardly projecting lip18. The lip18may be disposed at a bottom of the side wall12. For example, the lip18may be disposed and operatively coupled to a bottom end of the generally vertical second portion12b. The lip18may extend substantially along a length of the side wall12. Preferably, the lip18projects inwardly approximately ¼ inch from the side wall12. When forming a parking bumper using the parking bumper shell10, the lip18may help to maintain a heavy filling material, such as concrete, within the parking bumper shell10. Furthermore, the lips18provide co-planar surfaces that can be used as guides to level the filling material after pouring. For example, a trowel can be placed against the lips18; the lips18will hold the trowel level when the trowel is dragged across the parking bumper shell10to level surface of the filling material.

Additionally, the first and second side walls12may each include one or more internal ribs20that project inwardly from the first and second side walls12. The internal ribs20can also aid in holding the heavy filling material within the parking bumper shell10when a parking bumper is formed. The internal ribs20may also provide stability and structural rigidity to the overall parking bumper shell10to help the parking bumper shell10maintain its shape during transit. The internal ribs20may extend substantially along the length of the side walls12. The internal ribs20may have, for example, a semi-circular cross-section, a trapezoidal cross-section, a triangular cross-section, a rectangular cross-section, or any other suitable cross-sectional shape. Preferably, the internal ribs20project inwardly approximately ¼ inch from the side walls12.

If more than one internal rib20is provided, the internal ribs20may be spaced along a height of the side walls12. The internal ribs20may, for example, be spaced equally along the height of the side walls12. Preferably, the internal ribs20are disposed and operatively coupled to the interior of the outwardly tapered first portion12aof the side walls12. More preferably, two internal ribs20are provided and are equally spaced along the height of the outwardly tapered first portion12aof the side walls12.

Referring toFIGS. 16 and 17, the side walls12may also be equipped with undercut wings41to be embedded into the heavy filling material, and to thereby help hold and secure the side walls12of the parking bumper shell10against the heavy filling material cured within. The undercut wings41also lend strength and stability to side wall12prior to filling, e.g. during shipment or storage. The undercut wings41are planar and finlike, and extend from the interior of the side wall12at an acute angle thereto. A variety of acute angles may work acceptably, but an angle of 56.3 degrees between the undercut wing41and second side wall12bhas been found to yield acceptable results. Though the undercut wings41may be formed of any shape, they are preferably of a planar and parallelogram shape that will not interfere with nested stacking of multiple parking bumper shells.

Preferably, the undercut wings41are arranged in pairs, with the undercut wings41in a given pair oriented at an angle to one another. The acute angle between the undercut wings41and the side walls12traps a “wedge” of heavy filler material in the recess between undercut wing41and the side wall12. When the side wall12is pulled away from the heavy filler material, that “wedge” resists outward motion of the undercut wing41and, therefore, of the side wall12on which the undercut wing41is mounted. Further, orienting each of the undercut wings41within a pair in substantially different planes (e.g. at least 60 degrees apart) from one another helps the undercut wing pair to resist forces in a variety of directions. For instance, pulling the side wall12in a direction parallel to one undercut wing41will encounter resistance from the other undercut wing41in the pair. Additionally, the plane of each undercut wing41may simultaneously be oriented perpendicular to the base of the parking bumper shell10. This allows the undercut wings41to simply slide out of the injection molding core (not shown) when the parking bumper shell10is removed, minimizing cost of manufacture by greatly reducing mold complexity and eliminating the need for so-called “collapsing” parts on the mold core. This reduces the wear and tear on injection molding machinery greatly. Resistance to vertical forces tending to separate the parking bumper shell10from the heavy filler material is provided by the z-pullers (described below).

Preferably, a plurality of undercut wing pairs may be used along the length of the side wall12to help securely keep the entire side wall12tight against the heavy filler material once the filler material has set. While no undercut wings41are provided on the end wall16, additional undercut wings can be so provided, if desired; due to their short length, the end walls16do not tend to pull away from the heavy filler material significantly.

Referring again toFIG. 1, a logo plate or label22may be provided on an exterior of the top wall14and either one or both of the side walls12. The logo plate or label22may be adapted to receive lettering, symbols, or any other image or sign. For example, the logo plate or label22may be decorated with text or symbols designating the parking space by a number or as “Handicapped” or “Reserved”. During injection molding of the parking bumper shell10, a steel molding cavity (not shown) may be provided with a removable plate (not shown) for molding the logo plate22directly onto the parking bumper shell10. Depending on the depth of the portion of the cavity used to form each of the logo plates22, the logo plates may be raised (as shown inFIG. 1), flush with the exterior of the parking bumper shell10, or recessed into the parking bumper shell10. Alternatively, a weather- and fade-resistant adhesive label made of a thin, flexible material, such as acrylic tape pre-printed with text or symbols, may be placed on the parking bumper shell after manufacture. The exterior of either or both of the side walls12may further include one or more exterior ribs24that extend along the length of the side walls12.

Referring toFIG. 18, all or part of the parking bumper shell10exterior surface may be textured with a non-skid texture pattern or coating. Any commonly available non-skid texture pattern or coating material may be employed. The non-skid texture pattern may be molded into the parking bumper shell or may be applied after molding in the form of an adhesive sheet or coating. The parking bumper shell10ofFIG. 18has a non-skid texture pattern molded into the top wall14, with a rectangular space reserved for indicia, e.g. a label plate, parking directive, or company logo.

Referring toFIGS. 3 and 5, the top wall14may include one or more elongate knock-out pins21that extend inwardly from the top wall14. Each of the elongate knock-out pins21extends inwardly (i.e. has a length of) approximately ⅜ inch. The elongate knock-out pins21may be approximately ⅜ inch thick. The elongate knock-out pins21may, however, have any other suitable length or thickness. The elongate knock-out pins21may have, for example, a rectangular cross-section, octagonal cross-section, or any other suitable cross-sectional shape. Preferably, the elongate knock-out pins21have a circular cross-sectional shape.

Like the internal ribs20, the elongate knock-out pins21(also referred to herein as “z-puller pins” due to the cross-sectional shape of notches or detents23therein) can facilitate holding the form-setting heavy material within the parking bumper shell10when a parking bumper is formed. Referring toFIG. 4, a portion of the elongate knock-out pins21has a reduced thickness, thereby providing a notch or detent23, permitting heavy filling material to creep therein, and when hardened, provide resistance to maintain the heavy filling material within the parking bumper shell10. Each z-puller pin is an elongate knock-out pin21, wherein a portion of the elongate knock-out pin21has a thickness that reduces at a constant rate to form the z-shaped notch or detent23. The elongate knock-out pins21may have any other suitably shaped notch or detent23for retaining heavy filling material therein. For example, the elongate knock-out pins21may have a square, rectangular, or rounded notch or detent23.FIG. 21A,21B, and21C show three different views of a z-puller pin42with a support rib44attached. The support rib44is approximately triangular in shape and extends from the interior of top wall14to the side of z-puller pin42. The support rib44, if used, helps to lend structural strength and stability to the z-puller pin42. Alternatively, the z-puller pin42may be supported with an increased diameter base member, to provide extra support (not shown). As shown inFIG. 3, the elongate knock-out pins21may be provided as a substitute for the internal ribs20. Alternatively, as shown inFIG. 5, the elongate knock-out pins21may be provided in addition to the internal ribs20.

At a thinnest point, and by way of example only, the elongate knock-out pin21may have a thickness at the notch or detent23of approximately half its overall thickness, such as 3/16 inch for an elongate knock-out pin21having an overall thickness of ⅜ inch.

If more than one elongate knock-out pin21is provided, the elongate knock-out pins21may be spaced evenly along the interior of the top wall14. In the embodiment ofFIG. 3, four elongate knock-out pins21are provided and spaced along the interior of the top wall14such that two elongate knock-out pins21are equally spaced from a respective end wall16, and two elongate knock-out pins21are equally spaced from a respective hollow extension26. In the embodiment ofFigure 16, eight pairs of knockout pins42with support ribs are spaced across the length of the interior of top wall14. Additional configurations, attachment locations, and alignments of such knockout pins may be used, as desired.

The elongate knock-out pins21may be used for conventional injection molding purposes, such as facilitating removal of the injection molded parking bumper shell10from a steel injection mold core. However, it is recognized that other means of facilitating removal of the injection molded parking bumper shells10from an injection mold cavity may be employed, such as stripper bars, as an alternative to knock-out pins. Thus, while the term “elongate knock-out pins” is used herein, it is not intended to be limited to any operational requirements in terms of the manner in which the parking bumper shell10of the present disclosure is manufactured or removed from an injection mold core.

Due to the manner in which the detents are imparted to the elongate knock-out pins21during injection molding, it may be necessary when removing the injection molded parking bumper shell10from the mold core to pull the parking bumper shell10slightly up to provide clearance of portions of core of the mold used to form the notch or detents of the knock-out pins21, before pulling the parking bumper shell10out of the mold.

Referring toFIGS. 2 and 6, the top wall14may include one or more hollow extensions26that extend inwardly from the top wall14. The hollow extensions26are configured to receive an anchoring post (not shown) when the parking bumper is formed. The hollow extension26may have a height substantially equal to the height H of the parking bumper shell10, or may have a slightly smaller height such that the hollow extension26does not touch the ground (and cause unwanted rocking of the parking bumper) when the parking bumper shell is placed on the ground upright. Preferably, the parking bumper shell10has two conically-shaped hollow extensions26that extend inwardly from the top wall14. Each of the hollow extensions26may have, however, any suitable shape. As shown inFIG. 2, the two hollow conical extensions26may be spaced along the top wall14such that they are equally spaced from a respective end wall16. Alternatively, the hollow extensions26may be spaced to conform to the spacing of existing anchoring posts already provided in a given parking lot.

As shown inFIGS. 12-15, in addition or as an alternative to the “z-puller” elongate knock-out pins21or the internal ribs20, the conical extensions26may be provided with at least one annular bead25, at least partially about its circumference. Preferably, the annular bead25has a thickness on the order of 0.02 to 0.03 inch. The annular bead25can facilitate holding the concrete or other form-setting heavy material within the parking bumper shell10, by serving as an undercut in a manner similar to the internal ribs20or the notches or detents23of the elongate knock-out pins21.FIGS. 12-15demonstrate that a conical extension26having the annular bead25thereon may be used in combination with one or both of the elongate knock-out pins21or the internal ribs20as means to facilitate holding the form-setting heavy material within the parking bumper shell10. The conical extension26having the annular bead25may be employed as the sole means to facilitate holding the form-setting heavy material within the parking bumper shell10, without either the elongate knock-out pins21or the internal ribs20.

Referring toFIGS. 10 and 11, the parking bumper shells10may be nested on top of one another to conserve space during transportation and storage of the parking bumper shells10. As shown inFIG. 11, the hollow extensions26may be sized to allow for nesting of two or more parking bumper shells10. Accordingly, the interior of the hollow extensions26may be sized to substantially receive an exterior of another hollow extension26. In a particularly preferred embodiment, two of the parking bumper shells10may be nested with only an approximately 1 inch loss (i.e. the combined height of the two parking bumper shells10when nested for transit or storage purposes is approximately 1 inch greater than the height of a single parking bumper shell10).

Referring toFIGS. 6 and 7, the hollow extension26may include an inwardly projecting neck28and inwardly projecting fins30. The inwardly projecting neck28is disposed substantially around an interior circumference of the hollow extension26. The inwardly projecting neck28may be disposed at the lower portion26bof the hollow extension26. In addition, one or more fins30may be provided on the interior of the hollow extension26. Like the neck28, the fins30project into the interior of the hollow extension26. The one or more fins30may be disposed just above the neck28. The fins30may be spaced evenly about an interior circumference of the hollow extension26. The fins30and the neck28can aid in keeping the anchoring post secured in the hollow extension26. When an anchoring post is placed into the hollow extension26, the fins30and the neck28may be pushed against the anchoring post and provide resistance against movement of the anchoring post.

The neck28may be formed with keyway tabs47that narrow from the top of the neck to the bottom. The keyway tabs47are flexible enough to accommodate various sizes of steel reinforcing bar which are commonly used to anchor existing parking bumpers, and which may be inserted into hollow extension26as an anchoring post51, such as ½″, ⅝″, and ¾″ diameter (also known as #4, #5, or #6 size rebar, respectively). Such tabs are so spaced as to also accept other commonly used anchoring posts51, such as long lag bolts, long carriage bolts, oversized, headed landscape timber spikes, and lengths of metal rod. The narrowing profile of the tabs allows steel reinforcing bar (if used as an anchoring post51) to slide through easily when it is inserted downward through hollow extension26and into the ground at time of parking bumper installation, but the neck28tends to grip and resist movement in the opposite direction, as the chamfered-edge keyway tabs47(seeFIGS. 6 and 7) slightly deform and tightly grip the anchoring post51when extended therethrough. The keyway tabs47grip steel rebar especially well, because the keyway tabs47tend to engage the ridges formed on the surface of rebar. This helps to hold the parking bumper firmly against the parking lot surface, and also helps to prevent the anchoring post51from “riding up” out of the parking lot surface over time due to forces from ground freeze and thaw.

Referring toFIG. 7, the opening in the neck28may be in the shape of a keyway (approximately that of a rectangle superimposed upon a circle, with their centers at the same point, and with one dimension of the rectangle being greater than the diameter of the circle and the other dimension being less than the diameter of the circle). This shape not only allows for gripping of the anchoring post51as described above, but also for the insertion of a lifting tool (with an L- or T-shaped tip extension) that passes through the neck28when inserted. Once the lifting tool (not shown) is rotated 90 degrees about the axis of the neck28, the L- or T-shape on the extension then engages the keyway tabs47forming the neck28, and the lifting tool can then be used to lift the parking bumper. This method can be used to lift the parking bumper when it is in both the inverted and upright positions, as long as no anchoring post51is installed in the neck28at the time of lifting.

Referring toFIG. 8, the hollow extension26may include a ledge32that extends outwardly from the interior of the hollow extension26. The ledge32may be disposed in a top portion26aof the hollow extension26, which is located near the top wall14. The ledge32may be used to support a washer50or other means of retention. The ledge32may be further adapted to receive a cap36. To allow for proper positioning and sealing of the cap36, the ledge32may further include a shoulder34that is adapted to receive a top portion36aof the cap36. The shoulder34allows the cap36to sit within the hollow extension26such that the top portion36aof the cap36is flush with an exterior of the top wall14.

Referring toFIG. 9, the cap36is sized to fit in the top portion26aof the hollow extension26. The cap36may include a top portion36aand a bottom portion36b. The top portion36amay have a diameter that is larger than a diameter of the bottom portion36b. The top portion36aof the cap36is adapted to rest adjacent the shoulder34of the ledge32. The bottom portion36bof the cap36is adapted to fit within the ledge32of the hollow extension26.

The top portion36aof the cap36may also be surrounded by an annular bead45which fits into a corresponding annular groove46cut into the recess in the top wall14just above shoulder34. The interlocking fit of the annular bead45into the annular groove46helps to secure the cap36into the top wall14, and may be so tight as to require striking with a rubber mallet for installation. The extremely tight fit of the cap36into the parking bumper helps to prevent unauthorized removal (i.e. by prying) of the cap36from an installed parking bumper, e.g. after the bumper is anchored to the ground in its desired end-use location with one or more anchoring posts51, and also inhibits accidental loss due, for example, to adverse weather conditions.

The bottom portion36bof the cap36may include an internal recess38that tapers upward toward the top portion36aof the cap36. This recess38allows the cap36to sit over the anchor post51.

The bottom portion36bof the cap36may also include one or more outwardly projecting ribs40. The ribs40can help to secure the cap36within the ledge32of the hollow extension26. The outwardly projecting ribs40may have, for example, a semi-circular cross-section, a trapezoidal cross-section, a triangular cross-section, a rectangular cross-section, or any other suitable cross-sectional shape. The ribs40vertically extend substantially along a height of the bottom portion36bof the cap36. The ribs40may be spaced evenly about a circumference of the bottom portion36bof the cap36. Preferably, the ribs40extend outwardly approximately ¼ inch from the bottom portion36bof the cap36.

A method of forming parking bumpers using the parking bumper shells10of the present disclosure will now be described. The parking bumpers can be formed at a precaster's site by filling the parking bumper shell10with a suitable form-setting heavy filling material, such as concrete or asphalt. Advantageously, such form-setting material may be left-over concrete from other projects that would otherwise go to waste. Alternatively, the parking bumper shells10can be located adjacent their final, desired positions at the parking lot, so that once filled with a suitable form-setting heavy filling material the parking bumpers do not again need to be moved (except to be turned upright.)

To prepare the parking bumper shell10for filling, the parking bumper shell10may be inverted, so that the top wall14is disposed against the ground. The parking bumper shell10may then be filled, for example, with concrete, asphalt, or any other suitable form-setting heavy filling material. The form-setting heavy filling material may then be tamped if needed. To level the surface of the heavy filling material, a trowel or other suitable leveling tool may be run along the lips18of the first and second side walls12. Any heavy filling material that enters the hollow extensions26may easily be removed by any known methods, such as punching out the solidified portions within the hollow extensions26.

During filling, the weight of the heavy filling material may cause the side walls12of the parking bumper shell10to bow outward. This may result in a parking bumper with sides that are not parallel, planar, or square. To prevent this from happening, a rigid frame43may be used to support the parking bumper shell10during filling (seeFIG. 18.) The rigid frame43is built of a material strong and rigid enough (such as metal or high-tensile strength styrene plastic), and of dimensions thick enough, to maintain the side walls12of the parking bumper shell10straight as they are filled with the heavy filling material. The rigid frame43is in the form of a box, closed on all sides except the top, with an interior length and width equal to that of the exterior length L and width W of the parking bumper shell10, and with an interior height that can be greater than, less than, or equal to that of the exterior height H of the parking bumper shell10. This allows an inverted parking bumper shell10to be lowered into the rigid frame43from above prior to filling with heavy filling material, with the parking bumper shell's10side walls12lightly contacting the inner side walls of the rigid frame43. As previously stated, the height of the side walls of the rigid frame43may be less than or equal to the height H of the side walls12of the parking bumper shell10, or may extend slightly higher by an additional clearance Δh. That clearance Δh, for example, could be ⅛ to ¼ inch.FIGS. 19 and 20show a cross-sectional view of a parking bumper shell10placed into the rigid frame43before and after filling, respectively.

Once the parking bumper shell10has been inverted and placed in the rigid frame43, it is ready to be filled. Heavy form-setting filler material (i.e. concrete) is poured into the parking bumper shell10until it reaches the top of the side walls of the rigid frame43if the top of the side walls of the rigid frame43extends past the top of the side walls12of the parking bumper shell10. If the top of the side walls of the rigid frame43does not extend past the top of the side walls12of the parking bumper shell10, the heavy form-setting filler material is poured into the parking bumper shell10until it reaches the top of the side walls12of the parking bumper shell10. A trowel or similar straight-edged tool may be run across the top of the rigid frame43or the top of the side walls12of the parking bumper shell10to level the heavy filling material and remove excess. If the side walls of the rigid frame43are less than or equal in height to the height of the parking bumper shell10within, the filler material will be flush with the bottom of the side walls12, end walls16and lip18(if present). If the side walls of the rigid frame43extend above the parking bumper shell10by an additional clearance Δh, the filler material will fill the parking bumper shell10and also form a base pad49of height Δh across the base of the finished parking bumper. The outer edge of the base pad49will cover off the bottom free peripheral edge of the side walls12and end walls16. Advantageously, such a base pad keeps the lip18or lower edge of the side walls12and end walls16from scraping against the ground during installation, potentially causing the side walls12or end walls16to separate from the cured heavy filler material or damaging the parking bumper's exterior, e.g. by cracking the plastic.

To help speed production of parking bumpers at the work site, an alternate method of production may be employed once two or more parking bumpers have been completed. The advantage of this method is that it does not require use of the rigid frame member43, yet results in a completed parking bumper with planar, parallel, and square sides. Two completed, filled and dried parking bumpers may be inverted and then placed with an empty, inverted parking bumper shell10between them such that the lower side wall12bon each completed parking bumper is supporting the same lower side wall12bon the empty bumper in between. The empty parking bumper shell10may then be filled with the heavy filling material, and a trowel may be run across the surface of the two surrounding parking bumper shells to level the filling material in the center parking bumper shell. Excess heavy filling material may be wiped or troweled away from the end walls16of the just-filled parking bumper shell10. The parking bumpers on either side may be removed when the heavy filling material inside the parking bumper shell10in the center has set.

Yet another method of casting parking bumpers on-site with adequate support for the side walls12is to place a plurality of parking bumper shells10, inverted, into parallel recesses provided in the underside of their shipping pallet (not shown) and fill the parking bumper shells10with heavy filling material. Like the rigid frame43, the shipping pallet is built of a rigid material (e.g. wood) and of a thickness adequate to hold the side walls12of the parking bumper shell10planar, parallel, and square during shipping. Unlike the rigid frame43, however, the shipping pallet has several parking bumper shell-shaped recesses to provide a “gang form” for the casting of several parking bumpers simultaneously.

After the heavy filling material solidifies, the parking bumper may be lifted from the rigid frame using the above-described lifting tool (if the rigid frame is used,) transported to the desired parking lot or other location, and flipped upright at the desired, final location of the parking bumper. The undercut wings41, internal ribs20, lips18, and/or elongate knock-out pins21or42serve to secure the solidified heavy filling material and the parking bumper shell10together. Once the parking bumper is properly situated, anchor posts, e.g. suitably-sized rebar rods, may then be driven through the hollow extensions26into the parking lot using, for example, an impact drill. Alternatively, a lag shield and lag bolt may be placed in the hollow extensions26and received in the washer50. The lag bolt may then be tightened into place on the parking bumper using a ratchet wrench. The cap36may then be placed and secured in the ledge32of the hollow extensions26, using a mallet or hammer, for example. Any heavy filler material that enters or obstructs the neck28during casting will be easily cleared away by hammering when the anchoring post is inserted and hammered into place.FIG. 23shows a cutaway view of a parking bumper fully installed, with a representative anchoring post51used to secure the parking bumper to the parking lot surface.

By forming parking bumpers using the parking bumper shells10, the cost of the parking bumpers can be greatly reduced. The parking bumper shells10are inexpensive to produce and the pouring of the parking bumpers at a precaster's site using the parking bumper shells10is not very labor intensive. Also, prior art parking bumpers are typically produced using about eleven feet total of ½″ steel rebar cast into the concrete, which serves to prevent crack propagation in the concrete from causing a portion of the bumper to fracture off. In the present parking bumper, steel rebar does not need to be cast into the body of the parking bumper, because the plastic outer shell and the undercut features serve to hold the concrete in place, even if cracking of the filler material does occur within the parking bumper shell. In a prior art parking bumper, the rebar required to reinforce the concrete structure of the bumper contributed about half of the total material cost for that bumper, whereas in the present parking bumper, the cost of that steel rebar (and the labor to cut and install it) is avoided entirely. Additionally, precaster sites can maintain a supply of parking bumper shells10on site, and utilize left-over ready-mix or other heavy filling material to form parking bumpers. Moreover, the unfilled parking bumper shells10are relatively light as compared to conventional concrete parking bumpers and can be nested on top of each other. Thus, transportation, storage, and retail display space can be more efficiently used and overall associated costs can be greatly reduced. Thus, the parking bumper shells10of the present disclosure are suitable for sale at lumber yards or other home improvement stores, as a kit, together with Sakrete®, Quikrete®, or any other ready-mix concrete or heavy filling material mix, with or without a trowel or similar leveling tool, for do-it-yourself or independent contractor use.

While various embodiments have been described above, this disclosure is not intended to be limited thereto. Variations can be made to the disclosed embodiments that are still within the scope of the appended claims.