Movable or removable closures – Facially opposed primary and auxiliary closure for common... – Auxiliary mounted for movement
Reexamination Certificate
1999-01-21
2003-11-04
Strimbu, Gregory J. (Department: 3634)
Movable or removable closures
Facially opposed primary and auxiliary closure for common...
Auxiliary mounted for movement
C049S068000, C049S142000, C049S400000
Reexamination Certificate
active
06640495
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to hatches and similar apparatus for controlling access to installations such as submersible pump stations, pits, sewers, manholes, vaults, cellars, chutes, chambers, large receptacles, confined spaces, and the like. The present invention relates more particularly to a hatch which includes certain safety features to protect against a fall through the hatch and prevent unauthorized entry to a confined space.
2. Background Art
Access hatches and similar devices have been in use, in one form or another, for hundreds of years. A representative sample of such devices are disclosed in the following United States Patents: U.S. Pat. No. 4,266,380 to Samolis (1981); U.S. Pat. No. 3,521,537 to Forni et al. (1970); U.S. Pat. No. 3,198,094 to Dunkerley (1965); U.S. Pat. No. 1,523,191 to Gilfoy (1925); U.S. Pat. No. 1,442,737 to Schacht (1923); U.S. Pat. No. 1,244,501 to Jackson (1917); U.S. Pat. No. 1,068,856 to Clay (1913); U.S. Pat. No. 736,714 to Gendron (1903); U.S. Pat. No. 705,679 to Knapp et al. (1902); U.S. Pat. No. 202,373 to Purtell (1878); U.S. Pat. No. 195,965 to Straight (1877); U.S. Pat. No. 14,359 to Jenks (1856); and U.S. Pat. No. 14,107 to Moore (1856).
The hatches disclosed in these patents all present a potential safety hazard, in that the worker is usually exposed to an open hole when he or she is opening or closing the hatch door, cover, grate, etc. For example, to open or close the hinged grates in U.S. Pat. No. 4,266,380 to Samolis, the worker has to grasp the free side (opposite the hinged side) of the grate. This arrangement encourages the worker to stand near the free sides of the grates or to reach over the grates, exposing the worker to the hole as the grates are opened. A similar example is shown in U.S. Pat. No. 736,714 to Gendron—the handle is located at the free side of the door. A different example is shown in U.S. Pat. No. 3,198,094 to Dunkerley, where a handle to a door lever is located at the free side of a hinged door. The position of the handle encourages the worker to stand near or reach over to the free side of the door, thus exposing the worker to the risk of a fall. Thus, a need persists to improve upon the safety of hatches, especially during the process of opening and closing the hatches.
Another safety issue presented by hatches concerns the requirement that an adequate barrier be erected around the hatch opening. A number of attempts have been made to incorporate such a barrier into the hatch design itself, to eliminate the need for a separate barrier. Examples of such attempts are disclosed in the following U.S. Patents: U.S. Pat. No. 5,241,789 to Vacelet (1993); U.S. Pat. No. 4,266,380 to Samolis; U.S. Pat. No. 1,442,737 to Schacht; U.S. Pat. No. 1,244,501 to Jackson; U.S. Pat. No. 705,679 to Knapp et al.; U.S. Pat. No. 195,965 to Straight; U.S. Pat. No. 14,359 to Jenks; and U.S. Pat. No. 14,107 to Moore. Some of these designs have met with some success. However, they suffer from certain drawbacks. Some of these designs require an interconnection, by way of fasteners, clips or chains, between the “barrier components” (e.g., plates or grates) and the hatch cover. This arrangement creates the possibility that if such an interconnection fails, the entire barrier may fail. Fasteners, clips and chains are prone to failure over the useful life of the hatch. Another drawback is the complexity of the moving parts associated with the barrier components and the increased complexity of the hatch cover design. Such complexity leads to increased costs, maintenance and repair for the hatch. Thus, there is a need for a simple, reliable, and inexpensive approach to providing a barrier function in a hatch design.
Another safety issue is whether protection is afforded a worker against falling through the hatch opening (i.e., “fall-through protection”). A falling hazard can arise even where the hatch provides some means of fall-through protection. For example, U.S. Pat. No. 5,265,974 (1993) to Dargie describes a “safety net” for the hatch opening. Such a device may be adequate to prevent a fall through the hatchway. However, the net is to be pushed aside, like a shower curtain, to gain access through the hatch. The worker could inadvertently leave the net open after work is completed and the hatch is closed, thus creating a hazard to the next worker who opens the hatch. Thus, a need exists for fall-through protection that is less prone to human error.
The hazard of falling through a hatchway can be further reduced if the worker can perform certain work while the existing fall-through protection is in-place. Such an objective can be achieved if the fall-through protection permits limited access through the hatch. Also, in cases where apparatus connected to a utility line (e.g., a cable or hose) is to be brought up through the hatch for maintenance, the above objective can be achieved with fall-through protection that can be put back in-place once the apparatus is brought up for maintenance. The patents cited herein fail to address such additional versatility in fall-through protection for hatches.
There are instances when a worker may only need to look through a hatch and not enter through it. For example, a worker may need only to visually inspect equipment installed in a pit. In such a case, a worker, who is not trained or certified to enter the pit, can be assigned to such duties. However, once the hatch cover is opened, the untrained or uncertified worker may be tempted to enter the pit. It would therefore be advantageous to provide direct means for controlling the removal of the fall-through protection (e.g., the opening of a grate). For example, for a hatch having a cover and grate, a lock can be employed separately for the grate. An untrained or uncertified worker would be denied access to a key for the grate, thus preventing unauthorized entry.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an access hatch that avoids the limits and problems associated with the prior art.
It is another object of the present invention to provide an access hatch that prompts a worker to stand at a safe location when opening and closing the hatch.
It is a further object of the present invention to provide an access hatch with a grate, wherein the grate self-locks in an open position to provide a secure barrier on one side of the hatch.
It is yet another object of the present invention to provide an access hatch with a grate, wherein a simple self-locking hinge is provided to lock the grate in an open position.
It is yet a further object of the present invention to provide an access hatch with fall-through protection that is substantially immune from human error.
It is still another object of the present invention to provide an access hatch with fall-through protection, wherein the fall-through protection must be in-place before the hatch cover can be closed by a worker, thus ensuring that the fall-through protection is in place for the next worker who opens the hatch.
It is still a further object of the present invention to provide limited access through the hatch even though fall-through protection is in place, thus allowing a worker to perform minor maintenance tasks without removing the fall-through protection.
It is yet still another object of the present invention to provide an access hatch with fall-through protection that can be put back in-place once apparatus, connected to a utility line (e.g., a cable or hose), is brought up through the hatch for maintenance.
It is yet still a further object of the present invention to provide an access hatch with fall-through protection, wherein direct means are provided for controlling the removal of the fall-through protection, to prevent unauthorized entry.
These and other objects are attained in accordance with the present invention, wherein there is provided an access hatch having a frame, a grate, and a pull member or arm pivotally coupled to the grate. The frame contains an access ope
Duane Morris LLP
Strimbu Gregory J.
Syracuse Castings Sales Corp.
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