Fire escape – ladder – or scaffold – Wall- or floor-attached – Ladder
Reexamination Certificate
2000-12-18
2002-05-14
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Wall- or floor-attached
Ladder
C182S206000
Reexamination Certificate
active
06386318
ABSTRACT:
BACKGROUND—FIELD OF INVENTION
This invention relates to ladders usable as lifesaving equipment for persons who fall into the water from marine structures peculiar to yacht basins or small boat marinas, namely floating docks, walkways, and boat slips.
BACKGROUND—DESCRIPTION OF PRIOR ART
The surface decking of slips, docks, and walkways typical of marinas is generally no more than 15 to 20 inches above the water upon which they float. That spatial relationship, unaffected by tides, remains fairly constant and this tends to reenforce the general perception of marinas as safe havens. Consequently, few life-saving devices are to be found in marinas. For many marina occupants, however, the safe haven can, and has, become a death trap. Young adults in good health with good upper body strength can easily manage an unassisted escape from the water. The typical marina occupant, however, is an older person less physically fit with, perhaps, a child or a grandchild. Such persons are at risk of drowning should they fall into the water and there is no ladder available to them. Absent timely assistance from someone, such persons are in extreme danger of drowning.
Although data are difficult to generate it is beyond doubt that such drownings do occur. The present invention, in fact, was inspired by just such a drowning death on Dec. 24, 1999. The physical evidence at the scene of said drowning made it very clear that the victim had died for lack of a ladder.
The prior art of marine ladders useable as lifesaving equipment for persons who fall into the water are of two basic types: rigid ladders rigidly attached to marine structures, and stowable ladders designed for attachment to boats.
Of the said rigid ladders, most prior art has focused on the problems of large ship-berthing structures which may rise to considerable heights above water level. Several prior art patents combine water exit ladders with fender functions to protect ships' hulls from damage and to transport people between smaller boats, or the water, and elevated docks or quays. Japanese patent no. 55-19383 and U.S. Pat. Nos. 4,494,474 and 4,267,792 combine said ladder and fender functions. The prior art of such large-scale structures appears to have no practical application to such marine structures as are typical of yacht basins and marinas.
Usage in marinas and yacht basins has, for the most part, been to ignore the problem entirely or to rely upon rigid ladders, rigidly attached to selected locations to facilitate escape from the water. Such ladders necessarily remain partially submerged and thus, especially in salt water, become fouled with marine growth which, without periodic maintenance may render them inconvenient, or even unsafe, to use. In the nature of things such periodic maintenance seldom gets done and rigidly fixed ladders of whatever material will almost certainly become a home for a host of sharp-edged and slimy sea growth and, consequently, of marginal reliability as a life ladder.
Of the several marine-type ladders designed for installation on boats, most must be deployed by a person in the boat and are not accessible to a person in the water until they have been so deployed. Such devices are disclosed in U.S Pat. Nos. 4,813,514; 4,768,618; 4,724,925; and 5,117,940.
An exception to the above listed patents is U.S. Pat. No. 4,896,744, which discloses a potentially lifesaving ladder which stows under the decking of a pontoon boat and may be deployed, without assistance, by a person in the water. However, there seems no practical way to install the pontoon boat ladder on the structures appurtenant to the typical yacht basin or small boat marina.
Moreover, ladders which are appurtenant to boats which may or may not be in their slips are not a reliable substitute for safety devices installed as permanent fixtures of the marina environment.
The only prior art patent that is clearly relevant to conditions peculiar to marinas and yacht basins is disclosed in U.S. Pat. No. 4,365,689 filed on behalf of one Francis Dever in February of 1981. Said patent is for a tiltable, portable, pivotable ladder that stows horizontally above the water and may be easily deployed to a vertical position, and is intended to provide the means for unassisted escape from the water to the surface of a marine structure such as a floating dock. Moreover, the device is ballasted so that it will, automatically, return after use to a dry, horizontal stowage position.
It is clear that the Dever invention was aimed at the same problem as that which has inspired the present invention, namely that it is very difficult for persons in the water to escape, unassisted, from the water to the safety of even a relatively low-lying floating dock. Moreover, like the present invention, the Dever ladder stows horizontally out of the water so as to avoid fouling by marine growth, utilizes pivot means to go from stowed, horizontal position to deployed, vertical position; is ballasted; and is deployable from the water by a person unassisted. In all of that, the Dever ladder resembles the present invention. The resemblance, however, is more apparent than real and infinitely less significant than the differences which distinguish it from the present invention. The contrast here is between a workable concept and one which is essentially unworkable. The Denver device is dominated by considerations of portability and automatic function and by pivot means which have an axis that is parallel to the ladder's treads and thus require the ladder to pivot teeter-totter style on the edge of any structure to which it may be attached.
In consequence of said pivot means, the ladder, when in its stowed position, lies with its upper portion flat on the surface of the structure to which it is attached, a hazard to foot traffic; its lower portion protrudes outward over the water, a hazard to boating operations and possibly even swimming traffic.
The pursuit of portability and automatic function, for their part, have resulted in a light-weight ladder device, delicately balanced by means of metal washers serving as the ballast needed to move the ladder from stowage to deployment and back again with very little human involvement. The whole is attachable, ostensibly, by a pair of struts which attach at one end to said pivot means and at the other end are fitted with L-bolts situated so as to grip the edge of the deck planking of a floating dock, secured there by the tightening of wing nuts threaded onto the upper leg of said L-bolt.
The resulting attachment is so inadequate as to border on the whimsical. The weight of even a small child in swim wear, applied to the ladder, suspended as it is from the pivot means at the outer ends of said struts, would almost certainly peel the L-bolt clamping means away from the dock structure and render the ladder useless.
Another consequence of the Dever quest for portability and automatic function is a ladder designed to be relatively small. Drawings of preferred embodiments disclose a ladder having only two treads below the pivot means. The bottom most of these would, therefore, be just at or just below the water's surface. Persons seeking to climb onto a ladder step so near to the water's surface would need to exert considerable strength and ability to do so. For ease of access, the bottom tread of a life ladder should be submerged deeply enough upon deployment as to permit ease of access and require a minimum of physical prowess. This is a consideration of special urgency where the users of such a life ladder are likely to be aging adults and may be wearing water-soaked winter clothing.
Unfortunately, any attempt to lengthen the bottom portion of the Dever ladder would, first of all, be pointless without a more secure attachment means; and secondly, such lengthening would only exacerbate the hazardous condition created by the protruding lower portions of the stored ladder.
SUMMARY OF THE INVENTION
It is the purpose of this invention to provide a life ladder suitable for installation and service in a yacht basin or small boat mar
Stodola Daniel P.
Thompson Hugh B.
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