Two-sided manhole step

Abstract

A two-sided manhole step. The step includes a first step surface and a second step surface. Lugs extend from ends of the first and second step surfaces. The lugs help to prevent individuals from sliding off the manhole step, regardless of whether the step is installed with the first step surface or second step surface facing upwards.

Description

This application relates to and claims the benefit of U.S. Provisional Application No. 60/488,187, filed Jul. 17, 2003 and entitled “Two-Sided Manhole Step”, which is hereby incorporated in its entirety by this reference.

FIELD OF THE INVENTION

This invention relates to manhole steps and ladders, more specifically, the present invention relates to two-sided manhole steps.

BACKGROUND OF THE INVENTION

Pre-cast concrete manholes are widely used throughout the world to provide access to storm and sanitary sewer systems and a variety of other below-ground installations of piping, cables and the like. For such accesses to be used, a ladder or steps must be provided to permit workers to descend into and climb out of the manhole. A variety of structures have been employed to make this possible, including temporarily positioning ladders in the manhole and permanently attaching ladders or steps to the inside wall of the manhole.

One such step is disclosed in U.S. Pat. No. 4,100,997, which is incorporated herein by reference. U.S. Pat. No. 4,100,997 describes a steel reinforced plastic step that is injection molded of copolymer polypropylene. Support members that terminate at ends having molded, deformable annular projections are driven into preformed holes in the inside wall of the manhole. The disclosed step of U.S. Pat. No. 4,100,997 has an upper flat step surface attached to the two support members. At each end of the flat support surface is an upward projection member that projects at approximately 90° from the flat step surface.

Such upward projection members ensure that the manhole step complies with OSHA Standard No. 1910.27(b)(1)(v), which requires that the “rungs of an individual-rung ladder shall be so designed that the foot cannot slide off the end.” FIG. 1 shows an OSHA suggested design for rungs 8 on individual-rung ladders installed in concrete 6.

A problem occurs when manhole steps are installed and due to the installation process the steps are installed upside down. When steps such as the one shown in U.S. Pat. No. 4,100,997 or the one shown in FIG. 1 are installed upside down, they would no longer comply with the OSHA standards.

SUMMARY

Embodiments of the present invention include a two sided step which includes a first step surface, a second step surface, at least one attachment member for securing the step to a structure, first and second lugs extending substantially perpendicular from ends of the first step surface, and third and fourth lugs extending substantially perpendicular from ends of the second step surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) illustrates a prior art manhole step.

FIG. 1(b) illustrates a side view of a prior art manhole step of FIG. 1(a).

FIG. 2 illustrates a perspective view of an embodiment of the present invention.

FIG. 3 illustrates a top view of an embodiment of the present invention.

FIG. 4 illustrates a right side view of an embodiment of the present invention.

FIG. 5 illustrates a front view of an embodiment of the present invention.

FIG. 6 illustrates a back view of an embodiment of the present invention.

DETAILED DESCRIPTION

FIGS. 2-6 illustrate various views of a steel reinforced, molded plastic step 10 which is molded from plastic material such as polypropylene or other well-known plastic material. The step 10 is integrally formed having a step member 12 with a first flat step surface 14 and a second flat step surface 16 and respective opposed, step support members 18, 20 extending substantially perpendicular from the step member 12. The step support members 18, 20 are attachment members for securing the step 10 in the wall of a manhole or other desired structure. Various suitable attachment members, in any desired number or configuration, known to those skilled in the art can be used.

Each end of the step support members is provided with a means 22, 24 for retaining the step 10 in place in tapered holes or bores formed in the concrete wall of a manhole or other desired structure. Each end can be identical or similar in construction and can be molded to include a plurality of evenly spaced circular projections which may be smaller or less in diameter from one another such that the means 22, 24 taper towards distal ends. The operation of the ends is described in more detail in U.S. Pat. No. 4,100,997. Other means for retaining the step in concrete known to those skilled in the art can be used.

Both ends of the step member 12 have integrally formed lugs 26, 28, 34 and 36 that project outwardly from the first step surface 14 and project outwardly from the second step surface 16. As shown in FIGS. 2-6, the lugs extend substantially perpendicular from the first and second step surfaces. Ribbing 30, 32, located on the outside of the lugs, reinforces the lugs. Other means of reinforcement can be used as are known to those skilled in the art.

The lugs 26, 28, 34 and 36 can facilitate prevent a user's foot from slipping off a side of the step 10.

In the embodiments shown in FIGS. 4-6, the first step surface 14 can be identical to the second step surface 16. The first step surface 14 has reflection symmetry with respect to the second step surface 16.

In the embodiments shown in FIGS. 2-6, first and second step surfaces include treads 38 and 40 which may provide additional traction for the step's user. Treads 38 and 40 can be formed in several different designs and shapes as is known to one skilled in the art.

To install the step 10, two tapered openings or bores are first drilled into a wall of the manhole or other structure using a drill or other suitable means. In another embodiment, the openings are preformed in the wall. Next, the ends of the step support members are aligned with the respective openings and then hammered in place by a mallet or small sledge hammer, causing the circular projections to deform and securely hold the step 10 in the openings. Because the step 10 is symmetric with respect to its first and second step surfaces and associated lugs, the manhole step of the present invention can be installed with either step surface facing upwardly, so that it cannot be installed upside down.

As those skilled in the art will appreciate, the particular embodiment of this invention described above and illustrated in the figures is provided for explaining the invention, and various alterations may be made in the structure and materials of the illustrated embodiment without departing from the spirit and scope of the invention as described above.

Claims

1. A step comprising:

(a) a first step surface;

(b) a second step surface;

(c) at least one attachment member for securing the step to a structure;

(d) a first lug extending substantially perpendicular from a first end of the first step surface;

(e) a second lug extending substantially perpendicular from a second end of the first step surface;

(f) a third lug extending substantially perpendicular from a first end of the second step surface; and

(g) a fourth lug extending substantially perpendicular from a second end of the second step surface.

2. The step of claim 1, further comprising a top side and a bottom side, wherein the top side is symmetrical to the bottom side.

3. The step of claim 2, wherein the top side is a reflection of the bottom side.

4. The step of claim 2, wherein the top side comprises the first step surface, the first lug, and the second lug; and wherein the bottom side comprises the second step surface, the third lug, and the fourth lug.

5. The step of claim 1, wherein the manhole step is molded plastic.

6. The step of claim 5, wherein the manhole step is polypropylene.

7. The step of claim 5, wherein the manhole step is reinforced with steel.

8. The step of claim 1, wherein the first, second, third, and fourth lugs are reinforced.

9. The step of claim 8, further comprising ribs reinforcing the first, second, third, and fourth lugs.

10. The step of claim 9, wherein the ribs extend from outer surfaces of the first, second, third, and fourth lugs.

11. The step of claim 1, wherein at least portions of the first and second step surfaces comprise treads.

12. The step of claim 1, wherein the at least one attachment member comprises two step support members.

13. The step of claim 12, wherein the two step support members taper towards distal ends; and wherein the distal ends further comprise a plurality of projections circumscribing the ends.

14. A manhole step, comprising:

(a) a first step surface;

(b) a second step surface;

(c) two step support members for securing the manhole step to a structure; wherein the two step support members taper towards distal ends;

(d) a first lug extending substantially perpendicular from a first end of the first step surface;

(e) a second lug extending substantially perpendicular from a second end of the first step surface;

(f) a third lug extending substantially perpendicular from a first end of the second step surface; and

(g) a fourth lug extending substantially perpendicular from a second end of the second step surface.

15. The manhole step of claim 14, wherein the first, second, third, and fourth lugs are reinforced.

16. The manhole step of claim 15, further comprising ribs reinforcing the first, second, third, and fourth lugs.

17. The manhole step of claim 16, wherein the ribs extend from outer surfaces of the first, second, third, and fourth lugs.

18. A manhole step, comprising:

(a) a step, comprising: (i) a first step surface; (ii) a second step surface; (iii) a first lug extending substantially perpendicular from a first end of the first step surface; (iv) a second lug extending substantially perpendicular from a second end of the first step surface; (v) a third lug extending substantially perpendicular from a first end of the second step surface; (vi) a fourth lug extending substantially perpendicular from a second end of the second step surface; and (vii) wherein the first, second, third and fourth lugs are reinforced by a plurality of ribs; and

(b) two step support members extending substantially perpendicular from the step; wherein the two step support members taper towards distal ends; and wherein the distal ends further comprise a plurality of projections circumscribing the ends.

19. The manhole step of claim 18, further comprising a top side and a bottom side, wherein the top side is symmetrical to the bottom side.

20. The manhole step of claim 19, wherein the top side is a reflection of the bottom side.