Fire escape – ladder – or scaffold – Safety device – platform associated – Railing
Reexamination Certificate
2002-08-29
2004-12-14
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Safety device, platform associated
Railing
C182S128000
Reexamination Certificate
active
06830127
ABSTRACT:
FIELD OF THE INVENTION
This invention is in the field of pipeline construction safety devices and in particular the field of pipeline alignment instrumentation platforms for underground pipeline construction.
BACKGROUND OF THE INVENTION
The construction of underground pipelines, and in particular the construction of pipelines for the non-pressurized, gravity flow of wastewater with suspended solids, such as sanitary sewers and storm sewers, requires tight alignment and slope control. Such pipelines are typically constructed with a uniform pipe diameter, uniform slope and uniform alignment between manholes, with slope changes and alignment changes occurring at manholes only. The manholes are used for access for inspection, maintenance and cleaning of the pipeline. The uniform slope and alignment between manholes provides for the free flow of the waste water with the solids remaining in suspension and not settling out in the pipeline.
Modern construction techniques for such pipelines utilize a construction laser which emits a pinpoint laser beam on a selected alignment and slope for alignment and slope control as the pipeline is laid. The laser is simply mounted in the bottom of the manhole from which the next segment of pipeline is to be constructed. The laser must be adjusted to emit the laser beam on the alignment and with the slope desired for the construction of the next segment of pipeline which connects to the manhole. The horizontal alignment of the laser beam must be set based on reference to survey markers in place on the surface of the ground. While the construction lasers are self-leveling and therefore provide for simply dialing in the desired slope, the alignment of the laser must be surveyed in by reference to survey markers on the surface. The most commonly used method for aligning the laser is to position a surveying instrument known as a transit directly over the laser with the transit being above the surface of the ground with the survey markers in view. The transit can then be set on the proper alignment for the pipeline. With the pipeline trench dug away from the manhole a few feet thereby allowing the laser beam to be directed roughly in the direction of the desired pipeline alignment, the transit is rotated vertically from the desired alignment and the laser beam alignment is adjusted to match the alignment established by the transit. Thereafter, depending upon the soil conditions, the alignment can be checked as the pipe sections are laid and minor adjustments can be made to the laser alignment as the pipeline construction proceeds further away from the manhole. This can continue only so long as the pipe trench is not back filled as trench back filling will obstruct the view of the laser beam through the transit.
The manholes for sanitary sewer and storm sewer lines are generally constructed from pre-formed circular manhole sections which have an inside diameter of 4 feet, 5 feet or more. These manhole sections, which are usually several feet in height are stacked one upon the other on top of a manhole base. The number of manhole sections is dependent upon the depth of the pipeline at the manhole location. On top of the circular manhole sections, a manhole cone narrows the diameter of the manhole down to 2 ½ or 3 feet typically. On top of the cone, manhole rings are used to bring the manhole to the desired finish elevation, where the manhole cover is installed.
During the pipeline construction, typically the manhole sections are placed for a manhole up to the level where the cone would be installed. At this point, the transit that is used to align the laser for the next section of pipe is perched on tope of the manhole sections. This is accomplished by spreading the legs of the transit tripod placing them on top of the top manhole section, or placing a board or some other standing surface on top of the top manhole section, leaving an opening for the proper positioning of the transit over the laser. The transit operator is standing on some board on top of the manhole section at great safety risk to himself and others including particularly the workmen inside the manhole to adjust the laser.
An apparatus is needed that will improve efficiency and safety of the construction laser alignment procedure. Despite the inefficiency and obvious safety deficiencies of commonly used procedures, Applicant has found no prior art devices that are designed to address this need. U.S. Pat. No. 5,787,955 and U.S. Pat. No. 5,265,974 to Dargie disclose a safety net for a ground level hatch frame opening. U.S. Pat. No. 4,960,150 discloses a safety cover movable deck on tracks and rollers.
The objective of the present invention is to provide a movable platform which is mountable on the top of a manhole pipe section, providing a safer working surface for workmen for accessing the manhole to set up a pipeline construction laser and for setting up and operating surveying instruments for aligning the construction laser with the desired pipeline alignment.
SUMMARY OF THE INVENTION
The present invention is a safety platform for which a preferred embodiment comprises a platform deck, one set of four internal anchor pedestals for anchoring to the inside wall of a small diameter manhole section, another set of four external anchor pedestals for anchoring to the outside wall of a larger diameter manhole section, two opposing pairs of folding handrails with handrail anchor brackets securing the handrail sections to the platform deck, and four sets of safety barrier chains. For preferred embodiments, the platform deck is constructed of grating trimmed with structural angle. However, the platform deck can be constructed of plate material. Grating or plate material can be metallic, such as steel or aluminum, or non-metallic, such as fiberglass. The platform deck has an access opening which is likewise trimmed with structural angle to provide smooth edges for persons using the access opening. The access opening is positioned in the platform deck such that when the platform is positioned on the manhole the access opening outside edge is over the manhole inside wall and the manhole rungs, if there are any. This promotes easy access to the manhole from the platform deck and easy exit from the manhole to the platform deck. A pair of access cover rails is attached to the platform deck bottom, the access cover rail length typically being approximately twice the width of the access opening to allow for the access opening cover to be slid completely under the platform deck to an access position which provides for the access opening to be completely opened. Rail stop plates on each ends of the access cover rails confines the access cover to the access cover rails. Alternatively, tabs or other mechanisms can be used to confine the access cover to the rails. The distance between the access cover rails will generally be approximately equal to the length of the access opening since the length and width of the access cover will generally be approximately equal to the length and width of the access opening. This provides for a complete closure of the access opening when the access cover is in the closed position. A lock pin inserted through an upper lock pin opening in an upper lock pin collar, through the access cover and through a lower lock and opening in the lower lock pin collar secures the access cover in the fully closed or partially closed position. The upper lock panel collar and lower lock pin collar are welded to the top and bottom respectively of the access opening frame. A first handrail section and a second handrail section are anchored on opposing sides of the platform deck. The first handrail section is anchored to the platform deck by a pair of first handrail anchor brackets and the second handrail section is anchored to the platform deck by a pair of second handrail anchor brackets. The first handrail section and the second handrail section respectfully are secured in the upright position by a handrail lock pin inserted in anchor bracket lock pin holes in opposing anchor bracket sid
Chin-Shue Alvin
Nelson J. David
LandOfFree
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