Adaptable platform for loading and unloading railway cars

An apparatus that provides selectively deployable worker access with fall protection to at least a portion of the top of a container disposed above the ground. A gangway and its associated fall protection cage are selectively deployable from an elevated platform over the top of the container. The gangway and its associated cage are slidably connected to the platform via a track carried along the side of the platform.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

Not applicable.

FIELD OF THE INVENTION

The subject matter disclosed herein generally involves elevated platforms for accessing the tops of rolling stock for purposes of loading and unloading same, and particularly fall protection equipment provided for such elevated platforms.

BACKGROUND OF THE INVENTION

Long strings of railway tank cars are often pulled alongside of elevated platforms for the purpose of loading or unloading the contents of the tanks. These car strings usually are left coupled together, and the tops of the tanks carried by the cars generally need to be accessed by workers. This worker access typically is effected via a fold-down ramp or gangway. In accessing the tops of rolling stock (tank trucks, tank railroad cars, etc.), a gangway is lowered from the elevated platform to allow workers to move cargo between the platform and the top of the rolling stock. These gangways include cantilevers that usually carry a protective enclosure (aka cage) added to the outboard end to provide fall protection while the worker is on top of the rolling stock. Examples of these gangways are disclosed in U.S. Pat. Nos. 4,679,657; 5,042,612; 5,392,878; 7,140,467; 7,216,741 and 8,015,647, the disclosures of which being hereby incorporated herein for all purposes by this reference.

Because of variations in the lengths of railway tank cars, variations in the configurations of the tops of railway tank cars and operator error in positioning the railway tank cars relative to the platform, the gangways often are mounted on tracks that enable the gangway to slide along the length of the platform and thereby assume different positions with respect to the tops of the railway tank cars. An example of a track-mounted gangway is disclosed in U.S. Patent Application Publication No. 2012-0045274, the disclosure of which being hereby incorporated herein for all purposes by this reference.

Depending on how the string of cars is spotted, the length of track required to position the gangways along the length of the elevated platform can become quite large. The string of railway transport cars is usually spotted from one end of the string of cars or from the middle of the string of cars. The farther the car is from the spotting origin, the longer the length of track that the gangway must traverse in order to become properly positioned to allow the worker to access the top of the tank.

A self-closing gate provides access to the gangway when the gangway is moved opposite the opening to the car. Currently, side rails with the gates are bolted or welded on at specific locations of the elevated platform based on current anticipated needs. However, changes in lengths of cars and car configurations can result in additional track being needed than what was originally allowed for. Additionally, the relative locations of the self-closing gates and the fixed sections of side rail on each side of the platform may need to be changed in order to accommodate the different lengths of cars and different car configurations.

Emergency ladders often are used on these long platforms, and each emergency ladder is provided with its own self-closing gate that in turn provides access to the ladder from the elevated platform. Thus, to accommodate the different lengths of cars and different car configurations, the relative locations of the emergency ladder and its associated self-closing gate also may need to be changed so that it does not block movement of the gangway along the track in the platform.

If changed circumstances require reconfiguring the locations of each gangway and its self-closing gate as well as any emergency ladders and associated self-closing gate along the length of the elevated loading platform, effecting these changes poses problems of disassembly and re-assembly and the time and man-hours associated with completing these tasks.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate at least one presently preferred embodiment of the invention as well as some alternative embodiments. These drawings, together with the written description, serve to explain the principles of the invention but by no means are intended to be exhaustive of all of the possible manifestations of the invention.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the ranges and limits mentioned herein include all sub-ranges located within the prescribed limits, inclusive of the limits themselves unless otherwise stated. For instance, a range from 100 to 200 also includes all possible sub-ranges, examples of which are from 100 to 150, 170 to 190, 153 to 162, 145.3 to 149.6, and 187 to 200. Further, a limit of up to 7 also includes a limit of up to 5, up to 3, and up to 4.5, as well as all sub-ranges within the limit, such as from about 0 to 5, which includes 0 and includes 5 and from 5.2 to 7, which includes 5.2 and includes 7.

The longitudinal direction extends along the length of a structure, and the length of an elongated structure is the longest dimension of the structure. The transverse direction extends perpendicular to the longitudinal direction along the width of a structure, and the width of an elongated structure is the shorter orthogonal dimension of the structure. The vertical direction typically is the orthogonal direction that is normal to both the transverse direction and the longitudinal direction and typically is parallel to the direction in which the force of gravity would tend to operate when the apparatus in question is being used for its intended purpose.

When one structure is selectively attached to another structure or selectively connected to another structure, it means that the two structures are attached or connected at the option of the user and thus can be separated from one another at the option of the user without damaging the two structures and without damaging the fastening elements that were used to effect the connection or attachment between the two structures. Similarly, when one structure is detachably attached to another structure or detachably connected to another structure, it means that the two structures are attached or connected at the option of the user and thus can be separated from one another at the option of the user without damaging the two structures and without damaging the fastening elements that were used to effect the connection or attachment between the two structures. Typically, in both of these cases, the two structures can be reused repeatedly, and the fastening elements can be reused repeatedly as well.

An embodiment of the apparatus20of present invention that includes an elevated platform22for worker access to the tops13aof tanks13carried by railcars in accordance with the present invention is depicted from different vantage points in each of FIGS.3and7-9for example. More detailed aspects of embodiments of various components of embodiments of the elevated platform22are shown inFIGS. 1,2,4-6and10for example. As explained more fully below, because of the modular nature of some of these various components, different combinations of them can be made within the scope of the present invention so that one embodiment of one component may be combined with another embodiment of the same or a different component to yield a still further embodiment of the present invention.

As noted above, some embodiments of the apparatus20of the present invention may include an elevated platform, which is schematically represented by the element designated by the numeral22inFIG. 3for example. As shown in FIGS.3and7-9for example, the apparatus20desirably includes an elevated platform22that extends in a longitudinal direction and is defined in part by a deck22a. As shown from a head on view inFIG. 7and from a side view inFIG. 9, the deck22aof the elevated platform22typically is supported and suspended above the ground by a plurality of rigid legs22bthat are the elongated, underlie the platform22and carry same. These rigid legs22bdesirably may be formed from steel girders for example and are conventional in the art.

Some components of embodiments of the apparatus20of the present invention can be retrofitted to platforms22that already exist. However, unlike conventional elevated platforms in which the fixed railings and swing gates are welded permanently to the platform, the apparatus of the present invention permits non-destructive disassembly and detachable reassembly of these elements to the platform in order to accommodate repositioning of the swinging gates and the fixed railings in different arrangements and so permit worker access to different rail car configurations (especially regards the relative positioning of the loading hatches for the rail cars) as well as different rail train configurations (different rail cars connected successively in a different order in the train for example).

As schematically shown inFIGS. 3 and 8for example, the deck desirably has a pair of longitudinally extending sides that are separated apart from one another in the transverse direction, which is the direction that is normal to the virtual centerline21shown in dashed line inFIG. 8for example. As shown inFIG. 8for example, each side of the deck22adesirably is disposed to a respective opposite side of a virtual longitudinal centerline21that extends down the length of the platform22and is oriented normal to the transverse direction. As shown inFIGS. 8 and 10for example, the deck22adesirably is formed by steel decking that is rated to support the types of loads that are anticipated where the apparatus20will be installed.

As schematically shown inFIGS. 3 and 8for example, the apparatus20desirably includes a pair of longitudinally extending stringers23that form the opposite sides of the platform. As shown inFIG. 3for example, a first stringer23is disposed along one side of the deck, and a second stringer23is disposed along the opposite side of the deck.FIGS. 1 and 2illustrate an individual section of a modified metal I-bar that forms a section of an individual longitudinally extending stringer23. As shown inFIG. 1for example, each stringer23defines an upper flange23athat extends along the length of the stringer23and extends generally in the transverse direction. Moreover, each stringer23further defines a lower flange23bthat is spaced vertically apart from the upper flange23a. The lower flange23bextends along the length of the first stringer23and also extends in the transverse direction. As shown inFIG. 10for example, the upper flange23aof each stringer23defines a depending lip23cthat extends along the length of the stringer23and extends generally in the vertical direction from the upper flange23aa short distance toward the lower flange23bto form one side of a three-sided channel23d. As shown inFIGS. 1,2and10for example, the upper and lower flanges23a,23bof each stringer23form part of a trackway24that includes the channel23dand extends along the length of each respective stringer23and thus extends longitudinally down each side of the deck22a.

As embodied herein and indicated generally by the numeral30in each ofFIGS. 3,4and7for example, the apparatus20desirably includes at least a first gangway30, and desirably a plurality of gangways30such as shown inFIGS. 3 and 7for example. As shown inFIGS. 4 and 7for example, each gangway30has an inboard end30athat is configured to be constrained within the trackway24of one of the stringers23. As shown inFIG. 7for example, the inboard end30aof each gangway30is pivotally connected to the platform22and configured to slidably move along and generally within the trackway24of one of the stringers23. The manner of effecting the configuration of the inboard end30aof the gangway30so as to be slidable within the constraints of the first trackway24is conventional and disclosed for example in commonly owned U.S. Patent Application Publication No. 2012-0045274, the disclosure of which being hereby incorporated herein for all purposes by this reference.

As shown inFIGS. 4 and 7for example, each gangway30also includes an outboard end30bthat is spaced apart from and disposed generally opposite the inboard end30ain a transverse direction. As is conventional and shown inFIG. 7for example, a fall protection cage35can be provided and has an inboard end35aconnected to the outboard end30bof the gangway30. Moreover, as shown inFIG. 4for example, each gangway30is configured for pivotal movement of the outboard end30bwith respect to the inboard end30a.FIG. 4illustrates the operational mode of the apparatus20in which the gangway30is completely retracted as the gangway30is slidably moving within the trackway24down the length thereof, such movement being in the direction into and out of the view shown inFIG. 4for example. Conversely,FIG. 7illustrates the operational mode in which the apparatus20deploys a first gangway30from one side of the platform22and a second gangway30from the opposite side of the platform22in the fully extended mode so that each gangway30reaches the respective top13aof a tank13that is to be accessed by workers walking from the platform22onto the respective gangway30and onto the top13aof the respective tank13, which is shown in phantom by the chain dashed outline. Moreover, as schematically shown inFIG. 7for example, the outboard end35bof each fall protection cage35is deployed over the work area on the top13aof the tank13. Also shown in chain dashed outline inFIG. 7are the curved ladders14that provide access from each opposite side of the tank13, the safety railing15at the top of the ladders14carried by the tank13, and the service hatch16from which the cargo will be extracted from the tank13or loaded into the tank13, as the case may be.

The details of the gangway30are varied and conventional and can be learned for example from the disclosures in U.S. Patent Application Publication Nos. 2012-0045274 and 2012-0042458, the disclosure of each of which being hereby incorporated herein for all purposes by this reference. As embodied herein and shown inFIG. 3for example, the width of the gangway30is defined between a first side31of the gangway30and a second side32of the gangway30opposing the first side31of the gangway30. As shown inFIG. 7for example, the gangway30provides a walking surface33upon which workers can walk from the deck22aof the platform22onto the top13aof the tank13. The operative orientation of the gangways30is shown inFIGS. 3 and 7for example. As shown inFIG. 7for example, the walking surface33extends generally horizontally in a transverse direction from the platform22to the top13aof the tank13that is to be accessed by workers for inspection, loading or unloading. In its stored orientation shown inFIG. 4for example, the gangway30and its walking surface33is pivoted above the platform22and disposed generally at a right angle with respect to the deck22aof the platform22.

As shown inFIGS. 4 and 7for example, the walking surface33of the gangway30typically is bounded on each respective opposite side by a gangway railing that is indicated generally by the numeral34. The gangway railing34desirably is configured so that it can fold and collapse onto itself to permit the gangway30at the user's option to be raised above the normal horizontal walking plane and lowered to dispose the walking surface33of the gangway30in a position suited for workers to move between the top13aof the tank13and the deck22aof the platform22.

In accordance with the present invention, as shown inFIGS. 1,2and10for example, at least the upper flange of each stringer23defines a plurality of bolt openings25. The spatial arrangement of the bolt openings25in each stringer23on each opposite side of the platform22desirably is the same, but can be different in some embodiments. Moreover, these arrangements of bolt openings25can be done in pairs or triplets or any other multiple grouping instead of as a single bolt opening25, depending on the number of bolts needed to detachably anchor each of the modules of the platform railings and/or the gate modules50. In the examples given below, groupings in pairs of bolt openings25will be used to explain this aspect of the present invention.

In the embodiment shown inFIGS. 1,2and10, each grouping of bolt openings25includes two side-by-side bolt openings25wherein each bolt opening25is defined vertically through the upper flange23aof the stringer23. In this case, as schematically shown inFIG. 10for example, the magnitude of the linear distance in the longitudinal direction between each pair of side-by-side bolt openings25of each grouping of bolt openings25is a gap that is generally designated by the upper case letter G. Moreover, this gap G between the bolt openings25in each grouping of bolt openings25desirably will be the same throughout each such grouping of bolt openings25of the stringer23. A convenient reference point for measuring the distance that defines the gap G in the longitudinal direction between the pair of bolt openings25in a particular group of bolt openings25is the center of each bolt opening25. However, whether the reference point for the measures of the gap G is chosen as the point equidistant between the bolt openings25of each grouping or a different reference point doesn't matter so long as the chosen reference point remains consistent. Additionally, while there are two side-by-side bolt openings25in the embodiment of the grouping of bolt openings25depicted in the drawings, a different number of bolt openings25in each grouping of bolt openings25is contemplated and could be for example three bolt openings25in each grouping or for example just a single bolt opening25in each grouping. Naturally, in the case of the single bolt opening25in the grouping of bolt openings25, no gap would exist and G becomes zero and thus would be inapplicable, and the meaning of the term grouping in such an instance would default to a set with only one member.

In accordance with one embodiment of the present invention, there are two types of successive dual groupings of bolt openings25defined through the upper flange23aof each stringer23. Each type of successive dual groupings of bolt openings25is characterized by a different standard separation distance measured in the longitudinal direction. As schematically shown inFIG. 1for example, one of the two types of successive dual groupings of bolt openings25defined in at least the upper flange23aof the first stringer23is characterized by a relatively smaller spacing measured in the longitudinal direction between any successive groupings of bolt openings25, and this relatively smaller spacing distance is denominated a first spacing and designated by the alphanumeric S1. Moreover, as shown inFIG. 1each of these smaller first spacings S1has the same magnitude. Additionally, as schematically shown inFIG. 1for example, the other of the two types of successive dual groupings of bolt openings25defined in at least the upper flange23aof the first stringer23is characterized by a relatively larger spacing measured in the longitudinal direction between any the successive groupings of bolt openings25, and this relatively larger spacing distance is denominated a second spacing and designated by the alphanumeric S2. Moreover, as shown inFIG. 1each of these larger second spacings S2has the same magnitude. It should be noted that if only a single bolt suffices to anchor the posts of the railing modules or gate modules50, then each grouping will be defined by a single bolt opening25that is separated by either the first spacing S1or the second spacing S2.

Thus, as schematically shown inFIG. 1for example, the distance measured in the longitudinal direction between the end groupings of bolt openings25of two successive groupings of bolt openings25of the second type of successive dual groupings of bolt openings25characterized by the larger second spacing S2will have a magnitude that is a third spacing generally designated by the alphanumeric S3that is equal to two times (twice) the second spacing S2plus the first spacing S1, which is the separation distance between anchoring points of two side-by-side modules characterized by the unit spacing S2. In other words, 2×S2+S1=S3. Thus, as schematically shown inFIGS. 1 and 2for example, the S3magnitude is equal to a whole number multiple (2 in the case ofFIG. 1) of the S2magnitude plus the magnitude of the smaller spacing S1that exists between the two successive groupings of bolt openings25that are separated by the larger spacing magnitude S2.

Conventional loading platforms include conventional side railings or fencing as well as swing gates that control worker access between the platform and the tops13aof the tanks13for purposes of loading or unloading. Moreover, these conventional railings and swing gates are permanently welded to the conventional platform. However, instead of being permanently welded along the sides of the deck forming the elevated platform as in these conventional loading platforms, the platform railings in accordance with the present invention are broken up into modules of one or more standard lengths, and these railing modules in accordance with the apparatus20of the present invention are selectively, detachably bolted to the stringers23that form part of the trackways24disposed along the sides of the deck22aof the platform22of the apparatus21of the present invention. Similarly, in accordance with the present invention, each gate module50(described more fully hereafter) that includes a barrier52pivotally connected to a gate post51desirably is configured with a longitudinal dimension that permits a degree of interchangeability with embodiments of the modules of the platform railings40,44(described more fully hereafter). Moreover, in accordance with the present invention, embodiments of the modules of the platform railings40,44are configured so that the longitudinal dimension of the largest module of the platform railings40is some whole number multiple of the longitudinal dimension of the smallest of the modules of platform railings40and/or the gate module50plus the separation distance S1between the anchoring points of the side-by-side smallest modules.

As schematically shown inFIGS. 1 and 2for example, any two side-by-side unit modules, be they embodiments of platform railing modules44or embodiments of the gate modules50or one platform railing module44adjacent to an embodiment of one gate module50, can be interchanged with one of the larger platform railing modules40of the S3magnitude measured in the longitudinal dimension. Moreover, it is this uniformity of the magnitudes of the spacings between the bolt openings25and the arrangement of the groupings of bolt openings25that permits a modular approach to the detachable attachment of the various fall protection components, which are described in more detail hereafter and that include for example the platform railing modules40,44and embodiments of the gate modules50.

As schematically shown inFIG. 1for example, the apparatus20desirably includes at least a first platform railing module40that defines at least a first end post41and a second end post42that is spaced apart in the longitudinal direction from the first end post41. Each of the end posts41,42extends in a vertical direction and desirably can be connected by one or more horizontally elongated connecting rails45. Each end post41,42also has a vertically lower end that defines a foot flange43. Each foot flange43defines a grouping of bolt openings26, and these bolt openings26in the foot flange43are sized and spaced apart from one another in the same manner as each grouping of bolt openings25defined through the stringer23. Moreover, the magnitude of the spacing in the longitudinal direction between the bolt openings26of each grouping of each foot flange43of each platform railing module40is the same first spacing G described above in relation each grouping of bolt openings25defined through the stringers23. Additionally, the magnitude of the spacing in the longitudinal direction between the grouping of bolt openings26of the foot flange43of the first end post41and the grouping of bolt openings26of the foot flange43of the second end post42is a whole number multiple of the second spacing S2plus the first spacing S1. For the platform railing module40in the embodiment shown inFIG. 1, that whole number multiplier is the number 2. Moreover, as shown inFIG. 2for example, for a second type of platform railing module44that differs from the first platform railing module40by the different lengths of the connecting rails45, the magnitude of the spacing in the longitudinal direction between the grouping of bolt openings26of the foot flange43of the first end post41and the grouping of the bolt openings26of the foot flange43of the second end post42desirably can be equal to the magnitude of the second spacing S2alone. Thus, allowing for the longitudinal distances between each of the end posts41,42of each type of platform railing module40,44, the bolt openings26in the foot flanges43of each platform railing module40,44, will align with and correspond to the bolt openings25in the upper flange23aof the stringer23.

As shown inFIGS. 1 and 2for example, pluralities of threaded bolts27and mating threaded nuts28are provided. A threaded bolt27is selectively received through one of the respective bolt openings26of the foot flange43of one of the end posts41or42as well as through an aligned bolt opening25of the upper flange23aof the stringer23so as to selectively attach that respective end post41or42of the platform railing module40or44via a respective threaded nut28that is tightened on the end of the respective threaded bolt27. Similarly, a second threaded bolt27is selectively received through a respective bolt opening26of the foot flange43of the other end post41or42of the platform railing module40or44and successively through an aligned respective bolt opening25of the upper flange23aof the stringer23to selectively attach the opposite end post41or42of the platform railing module40or44via a second threaded nut28that is tightened on the end of the second threaded bolt27. In this way, each platform railing module40or44can be detachably connected to the platform22via the threaded nuts28attached to the threaded bolts27. Moreover, removal of each platform railing module40or44is easily achieved by undoing the bolts27and nuts28without damaging either the platform22, the platform railing module40or44or the bolts27and nuts28. Thus, use of the apparatus20of the present invention easily accommodates different rail car configurations and different train configurations pulled up alongside of the platform22for loading or unloading.

As shown in FIGS.6and8-10for example, the apparatus further desirably can include a plurality of swing gate modules50that are detachably connected to the platform22. As shown inFIGS. 1,2and10in particular for example, each gate module50is detachably connected to the upper flange23aof the stringer23of the platform22. As schematically shown inFIG. 3for example, gate modules50desirably are configured and disposed so as to selectively control ingress and egress of workers between the deck22aand one of the gangways30. Alternatively, as explained more fully below, gate modules50also desirably are configured and disposed so as to selectively control ingress and egress of workers between the deck22aand one of the emergency egress ladders17(e.g.,FIGS. 6 and 10).

As shown inFIGS. 1,2and10for example, each gate module50desirably includes at least one gate post51and a gate barrier52that is pivotally connected to the gate post51. Moreover, as shown inFIG. 10for example, the pivotal connection between the barrier52and the gate post51desirably is effected by a spring-biased hinge connection53that biases the position of the barrier52in the closed position such as shown inFIGS. 1 and 2for example. In the closed position, the gate module50desirably has its barrier52disposed so as to block passage of workers between the deck22aand a gangway30or an emergency egress ladder17(e.g.,FIGS. 6 and 10). In the closed position, the gate module50desirably has its barrier52disposed in alignment with the adjacent platform railing module40or44. As shown inFIGS. 1,2and10for example, the barrier52of the gate module50desirably is provided with a stop flange54that prevents the spring-biased hinge connection53from moving the barrier past alignment with the adjacent platform railing module40or44. However, as schematically shown inFIGS. 3,8and10for example, each gate module50desirably is configured so that the spring-biased hinge connection53permits the worker to pivot the barrier52manually in a manner to swing the barrier52inwardly toward the longitudinal centerline21of the deck22ato open up worker passage between the deck22aand a gangway30or an emergency egress ladder17(e.g.,FIGS. 6 and 10).

As shown schematically inFIG. 1for example, the gate post51of each swing gate module50extends in a vertical direction and has a vertically lower end that defines a foot flange55. In an alternative embodiment shown inFIG. 10for example, a single post serves as both the gate post51of the swing gate module50and an end post42of an adjacent platform railing module44, and thus the gate post51and the end42post share a foot flange43,55. In each case, the foot flange43,55defines a group of bolt openings26,56. The magnitude of the spacing in the longitudinal direction between the bolt openings56of the foot flange55of the gate post51is the same as the magnitude of the gap G in the foot flange43of the end posts41,42of the platform railing module40,44and thus the same as the gap G between the bolt openings25of the upper flange23aof the stringer23.

As schematically shown inFIG. 1for example, the longitudinal extent of some embodiments of the gate module50desirably is one half of the longitudinal extent of one embodiment of the larger of the fixed railing modules40. As schematically shown inFIGS. 2,6and9for example, the longitudinal dimension of some embodiments of the gate module50plus the longitudinal dimension of some embodiments of the smaller of the fixed railing modules44equals the longitudinal dimension of the larger of the fixed railing modules40. Accordingly, some embodiments of each gate module50configured so that when aligned in succession with one of the smaller of the fixed railing modules44, these two components of the apparatus20are be interchangeably detachably connected to upper flange of the stringer23with the larger of the fixed railing modules40. Similarly, some embodiments of the gate modules50are configured so that when two of these embodiments of the gate modules50are aligned in succession they are interchangeably detachably connected to the upper flange23aof the stringer23with the larger of the fixed railing modules40.

As shown inFIGS. 4-6and10for example, conventional platforms may be provided with one or more emergency egress ladders17that are rigidly fixed to the platform22. As shown inFIG. 6for example, each such emergency egress ladder17includes a plurality of rungs18disposed horizontally between a pair of opposing side rails19and successively in a vertical direction downwardly from the platform22to permit workers to escape from the platform22in an emergency situation. As shown inFIG. 10for example, the top rung18aof the emergency egress ladder17is disposed closest to the platform22among the plurality of rungs18. The top rung18aand the uppermost ends19aof the side rails19of the fixed emergency ladder17are disposed beneath the platform22so as not to interfere with the passage of the gangway30sliding along the trackway24up and down the length of the platform22. It is conventional therefore to provide a gate at the location of each of these fixed emergency egress ladders17, and this gate is biased in the closed position that blocks passage from the deck22aof the platform22to the top of the emergency ladder17. Thus, in order to descend the emergency ladder17, workers must open the gate disposed at the top of the ladder17and turn 180 degrees before stepping backwards with one foot to descend the ladder17. However, in an emergency situation, each worker who is rushing to descend the fixed emergency egress ladder17must take care in assuring that the worker's first step makes contact with the upper rung18aof the emergency ladder17. Moreover, this first step must be taken in a direction that not only is descending from the platform22but also spaced apart in the transverse direction from the platform22, thereby increasing the chances of a misstep, especially during an emergency in which the workers are in a hurry to leave the deck22aof the platform22and descend the ladder17to reach the safety on the ground.

In accordance with the present invention as schematically shown inFIGS. 4-6and10for example, embodiments of the apparatus desirably can include one or more ladder extension modules60. As shown inFIG. 10for example, each ladder extension module60is configured to be disposed in general alignment with the top of the emergency ladder17that extends vertically beneath the platform22. As shown inFIGS. 4-6for example, each ladder extension module60desirably is configured so as to be detachably connected to the platform22. As shown inFIG. 10for example, each ladder extension module60is desirably configured so as to be detachably connected to the upper flange23aof the stringer23on one side of the deck22a. However, a ladder extension module60desirably can be retrofitted to a pre-installed swing gate that is disposed to provide access to a fixed emergency egress ladder17.

Moreover, as schematically shown inFIG. 10for example, the longitudinal dimension of one embodiment of a ladder extension module60desirably is the same as the longitudinal dimension of three of the smaller of the fixed railing modules44or the longitudinal dimension of three of one of embodiments of the gate modules50. Accordingly, one embodiment of a ladder extension module60is configured to be interchangeably detachably connected to the upper flange23aof the stringer23in place of two of the smaller of the fixed railing modules44and one of one embodiment of the gate modules50in succession. Alternatively, one embodiment of a ladder extension module60is configured to be interchangeably detachably connected to the upper flange23aof the stringer23in place of one of the larger of the fixed railing modules40and one of one embodiment of the gate modules50in succession.

As shown inFIG. 10for example, each ladder extension module60desirably includes a pair of sidebars61,62, and a first sidebar61is longitudinally spaced apart from a second sidebar62that is disposed generally in parallel with the first sidebar61. Furthermore, as shown inFIGS. 5 and 10for example, each ladder extension module60desirably includes for each sidebar61,62, at least a first linkage63and desirably a plurality of linkages63. As shown inFIG. 10for example, each linkage63has one end pivotally connected to the sidebar61or62and a second end pivotally connected to the gate post51for the gate, whether it is the gate post51with the spring biased hinge or the gate post41of a railing module40or44that is disposed longitudinally spaced apart from the gate post51with the spring biased hinge53.

As schematically shown inFIG. 5for example, the pivoting movement of the sidebars61with respect to the linkages63renders the ladder extension module60selectively deployable between an extended mode and a retracted mode. In the view ofFIG. 5, the retracted mode is indicated by the dashed outline, while the extended mode is indicated by the solid outline of the first sidebar61that is visible in the view ofFIG. 5. When the ladder extension module60is deployed in the extended mode as schematically shown inFIGS. 5,8and10for example, the sidebars61,62are disposed in the extended position. As schematically shown inFIG. 5for example, the sidebars61,62are disposed in a retracted position and folded against the gate post51or end post41or42(as the case may be) when the ladder extension module60is disposed in the retracted mode (dashed outline inFIG. 5). As shown inFIGS. 5 and 10for example, in the extended mode, the respective sidebar61or62of the ladder extension module60is disposed spaced apart from the associated gate post51,41or42by a distance that is substantially comparable to the length of one of the respective linkages63. Moreover, as schematically shown inFIG. 4, when the ladder extension module60is disposed in the retracted mode, the sidebars61,62are thus disposed in their retracted positions wherein each sidebar61,62rests against the respective connected gate post51or end post41or42. In the retracted mode schematically shown inFIG. 4, the ladder extension module60is configured so as to permit the gangway30to bypass the ladder extension module60as the gangway30slides longitudinally along the trackway24.

As shown inFIG. 10for example, each ladder extension module60includes a ladder rung64that is connected between the pair of sidebars61,62, and accordingly this ladder rung64is selectively deployable between an extended mode and a retracted mode along with the sidebars61,62. In retracted mode, the ladder rung64of each ladder extension module60is disposed close enough to the longitudinal centerline21of the deck22aso as to allow each gangway30to bypass the ladder rung64as the gangway30moves slidably along the trackway24.

When the ladder extension module60is deployed in the extended mode, the sidebars61,62are disposed relatively farther away from the longitudinal centerline21of the deck22a. As shown inFIG. 10for example, when the ladder extension module60is deployed in the extended mode, the sidebars61,62assume a disposition so that they are substantially vertically aligned with the upper ends19aof the fixed emergency ladder17. Moreover, as shown inFIG. 10for example, when the ladder extension module60is deployed in the extended mode, the ladder rung64of the ladder extension module60is likewise disposed in vertical alignment with the ladder rungs18a,18bof the fixed ladder17. Additionally, as shown inFIG. 10for example, when the ladder extension module60is deployed in the extended mode, the disposition of the ladder rung64in the ladder extension module60desirably is disposed so that the vertical distance between the top rung18aof the fixed ladder17and the rung64of the ladder extension module60is substantially the same as the vertical distance that separates at least the two uppermost rungs18a,18bof the fixed ladder17. The vertical distance separating the uppermost two rungs18a,18bof the emergency egress ladder17is deemed to be substantially the same as the vertical distance between the top rung18aof the emergency egress ladder17and the rung64of the ladder extension module60when the user of same is unlikely to notice any difference in vertical height during descent of the emergency ladder17via the ladder extension module60. In this way, when the ladder extension module60is deployed in its extended mode, the ladder extension module60assumes a configuration that acts as an uninterrupted extension of the fixed emergency ladder17, both as to the orientation of the sidebars61,62with the side rails19of the emergency ladder17and the orientation of the ladder extension's rung64with the rungs18of the emergency ladder17.

Because of these standardized length dimensions of the anchoring points of the modules40,44,50,60and the commensurately standardized spacing of the bolt openings25along the upper flanges23aof the stringers23in accordance with one aspect of the present invention, the same platform railing modules40,44, and swinging gate modules50can be selectively detached and moved to different locations along the platform22and positioned in different arrangements with respect to one another. Moreover, the same detachably interchangeable advantage is secured through use of the ladder extension module60in accordance with this aspect of the present invention.

While at least one presently preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.