Abstract: A momentum arresting ramp that includes a plurality of steps that each includes a slider receiving surface and a transition surface. The steps may enable a device with wheels to be moved down the ramp by a user, without inconvenient gravity building momentum of the device down the ramp. For example, the steps may be spaced apart along a first axis such that a first slider of the device is never in contact with one of the transition surfaces when a second slider of the device is in contact with another one of the transition surfaces. The configuration of the steps and the sliders may enable the device (e.g., a device heavy enough to typically require two users to unload using a planar ramp) to be easily and conveniently unloaded by a single user.

Abstract: A cage for surrounding a section of a work area of the top of rolling stock includes an inboard side, an outboard side, a front end section and a back end section. The inboard side of the cage is attached to an associated deployment apparatus. Each of the two sides can define a pair of fence notches to slide over the rails surrounding the work area. Each of the two end sections can define an inboard notch and a center notch. Some embodiments of the end sections can define an outboard notch that includes a self-adjusting straddle. The cage can be provided as part of a portable fall protection device that includes a telescoping positioning mechanism.

Abstract: This invention relates to a stair assembly to be arranged in a stairwell opening of an upper floor, comprising: —a girder assembly; —a plurality of steps mounted to the girder assembly; and —a guard structure, wherein the girder assembly is pivotably mountable to the upper floor to pivot about a pivot axis between an operational position, in which the girder assembly extends obliquely downwards, and a hidden position, in which the girder assembly extends horizontally, wherein the moveable guard structure is moveable between an operational position, in which the guard structure extends upwards, and a hidden position, in which the guard structure has moved downwards, and wherein the stair assembly is configured such that when the girder assembly and the guard structure are in their respective hidden positions a person is able to walk over the stair assembly as part of the upper floor.

Abstract: A retractable staircase having a first side stringer and a second substantially parallel side stringer connected to a plurality of steps. The first side stringer is fixedly attached to a wall and the second side stringer is pivotally movable about the first side stringer between an extended position, where the steps lie substantially horizontally between the stringers, and a retracted position where the steps lie substantially vertically between the stringers. The retractable staircase also includes a collapsible handrail and a gate that are interconnected with the side stringers and the pivoting steps so that when one of them is moved, the other two move substantially simultaneously.

Abstract: The present disclosure relates to stair systems and methods for allowing stair movement, including rotational movement, between building levels while maintaining the structural integrity of the stair system for safe egress passage and ingress passage. The systems and methods of the present disclosure allow for independent movement of the surrounding building walls, landings, floor slabs, and/or any other portion of the surrounding building structure or stair system. Embodiments of the present disclosure are suitable for use in both new constructions as well as in existing constructions for retrofit applications to allow for movement between levels, landings, or within stairwell structures. The present disclosure can reduce stair damage during building movement whether it is from wind, thermal, explosive, or seismic activity, and/or any other type of suitable force or experience, as the present disclosure allows for rotational movement, longitudinal movement, or a combination thereof.

Abstract: The present disclosure relates to stair systems and methods for allowing stair movement between building levels while maintaining the structural integrity of the stair system for safe egress passage. The systems and methods of the present disclosure allow for independent movement of the surrounding building walls, landings, floor slabs, and/or any other portion of the surrounding building structure or stair system. The embodiments of the present disclosure are suitable for use in both new constructions as well as in existing constructions for retrofit applications to allow for movement between levels, landings, or within stairwell structures. The present disclosure reduces stair damage during building movement whether it is from wind, thermal, or seismic activity, and/or any other type of suitable force or experience, as the present disclosure allows for directional movement, or a combination thereof, including tension and compression, lateral, or vertical movement.

Abstract: A retractable vehicle step assembly includes a drive shaft having a spline and a step coupled to the drive shaft through a step linkage system. The step is moveable between an extended position and a retracted position. The step linkage system includes a first step linkage defining a spline engagement opening for engagement with the spline of the drive shaft and a fastener. The fastener is adjustably coupled to the first step linkage so as to clamp the spline engagement opening of the first step linkage around the drive shaft. Upon loosening the fastener, the first step linkage is disengageable from the drive shaft and the step is moveable from the extended position to the retracted position regardless of rotation of the drive shaft.

Abstract: Folding ladder assembly includes upper and lower ladder sections, and first, second, and third linkage assemblies. First linkage assembly includes at least a first linkage assembly linkage member. Second linkage assembly includes at least a second linkage assembly first linkage member pivotably coupled to upper and lower ladder sections. Third linkage assembly includes at least portions of the first linkage assembly linkage member and the second linkage assembly first linkage member. Movement of the first linkage assembly results in movement of the upper ladder section, the second linkage assembly, the third linkage assembly, and the lower ladder section.

Abstract: Apparatus to equip an existing stair case with no hand railing with hand railings with the purpose of aiding a person with reduced capacity to climb up and down stairs. The apparatus includes features that permit the system to adjust to a large inventory of existing stair cases and to be installed without making any damage to existing installation. The apparatus is comprised of oversteps, railings, fixed height railing supports, adjustable height railing supports, attachments to prevent tripping, a half step and hardware to attach all the pieces together such as bolts, nuts, butterfly nuts, washers and screws. No need for repairs to existing installation once the adjustable stair system with railings is removed. The apparatus is movable, re-usable and may be installed indoors and outdoors.

Abstract: A self-leveling staircase. The staircase has a first flight of self-leveling steps having a first end adjacent to the ground and a plurality of stair treads pivotally attached at a right edge to a first pair or stair rails and at a left edge to a second pair of stair rails. A self-leveling platform is pivotally attached on a second end of the first flight of self-leveling steps and to the first and second pair of stair rails. A second flight of self-leveling steps having a first end is pivotally attached to an opposite side of the self-leveling platform from the first flight of self-leveling steps. The second flight of self-leveling step has a plurality of stair treads pivotally attached at a right edge to a third pair of stair rails and pivotally attached at a left edge on front and back ends thereof to a fourth pair of stair rails.

Abstract: The present disclosure relates to stair systems and methods for allowing stair movement between building levels while maintaining the structural integrity of the stair system for safe egress passage. The systems and methods of the present disclosure allow for independent movement of the surrounding building walls, landings, floor slabs, and/or any other portion of the surrounding building structure or stair system. The embodiments of the present disclosure are suitable for use in both new constructions as well as in existing constructions for retrofit applications to allow for movement between levels, landings, or within stairwell structures. The present disclosure reduces stair damage during building movement whether it is from wind, thermal, or seismic activity, and/or any other type of suitable force or experience, as the present disclosure allows for directional movement, or a combination thereof, including tension and compression, lateral, or vertical movement.

Abstract: A retractable staircase having a first side stringer and a second substantially parallel side stringer connected to a plurality of steps. The first side stringer is fixedly attached to a wall and the second side stringer is pivotally movable about the first side stringer between an extended position, where the steps lie substantially horizontally between the stringers, and a retracted position where the steps lie substantially vertically between the stringers. The retractable staircase also includes a collapsible handrail and a gate that are interconnected with the side stringers and the pivoting steps so that when one of them is moved, the other two move substantially simultaneously.

Abstract: A stair system with freedom of movement between landings associated therewith includes a connection system configured to connect stairs to a landing associated with a construction, wherein the connection system structurally supports the stairs for safe egress over the stairs while concurrently supporting movement between the landing and a second landing associated with the construction by the stairs in at least one dimension, and wherein the movement supports inter-story drift between the landing and the second landing and removes some force translation between the landing and the second landing.

Abstract: A work vehicle comprising: a cab, an inside of which is a cockpit, having a window portion; a vehicle body having a passage on a periphery of the cab; a front lateral wiper provided so as to be rotatable around a first axis and along the window portion, and rotating around a second axis that extends in a different direction with the first axis in a movement range between a normal position that is in contact with the window portion and a rising position separated from the window portion; and a passage fence extending along an outer edge of the passage. The passage fence is configured to open upward with penetrating the passage fence inwardly and outwardly, and a part of the passage fence has an opening that includes the movement range of the front lateral wiper.

Abstract: A loading apparatus is provided that includes a set of stairs, a platform, and a handle. The stairs are attached to the platform and the platform has a locking mechanism. The handle has a first end that is pivotally attached to the set of stairs and the locking mechanism is capable of engaging the handle.

Abstract: A ladder for use with heavy machinery such as farm equipment, the ladder having platform steps, the ladder being convertible between a deployed position for supporting a person or other load, to a storage, scaffold, or ramp position in which the steps lie in a generally planar arrangement. When deployed, the ladder steps remain parallel to each other. The ladder includes two frames, the frames pivotably connected by a plurality of platform steps, one of the frames being pivotably attached to a piece of heavy machinery. The frame nest within one another in the storage configuration. The pivotable attachment to the heavy equipment may be wheels on the ladder frame that engage horizontal tracks on the heavy equipment, allowing the ladder to be lifted up, the frames nested, and the ladder in the storage configuration slid along the tracks and stored.

Abstract: A system for providing a flexible cover in a storage tank is provided that reduces the amount of vapors released from a hydrocarbon liquid and other liquids and reduces the amount of product (liquid) lost to the atmosphere. The flexible cover is, in some embodiments, comprised of one or more membranes joined together along their respect perimeter edges. The membranes are made from a material or materials that allow the cover to roll up, or otherwise reduce the cross sectional diameter or area of the cover, to allow the membrane to pass through a port in a storage tank. Once inside the storage tank, the cover may return to its normal and/or predetermined dimensions to cover the upper surface of the hydrocarbon or other liquid, which reduces the release of vapors from the hydrocarbon liquid and other liquids.

Abstract: An upper level of a multi-level building is guarded from flooding by water present in one of the levels of the building where the upper level is reached from the lower level (or vice versa) by connecting stairs. A flight of stairs bridging the levels is buoyant and pivotally connected to the building at one end of the flight adjacent one of the levels such that on occasion of water rising originating in one of the levels, the flight rotates upward on the axis of the pivot to block water from entering the upper level.

Abstract: A stair system with freedom of movement between landings associated therewith includes a connection system configured to connect stairs to a landing associated with a construction, wherein the connection system structurally supports the stairs for safe egress over the stairs while concurrently supporting movement between the landing and a second landing associated with the construction by the stairs in at least one dimension, and wherein the movement supports inter-story drift between the landing and the second landing and removes some force translation between the landing and the second landing.

Abstract: A ladder having platform steps, the ladder being convertible between a deployed position for supporting a person or other load, to a storage, scaffold, or ramp position in which the steps lie in a generally planar arrangement. When deployed, the ladder steps remain parallel to each other and form a series of parallelograms with the rails of the ladder. The ladder is also capable of being locked or secured at various angles of deployment. The ladder further includes receivers to selectively receive accessories such as wheels, hooks, handles, or pads. The addition of accessories such as wheels allows the ladder in the storage position to be used as a creeper, dolly, or cart.

Abstract: A lanyard assembly for lifting a rescue stretcher, includes a lifting gear with a lower fastening arrangement to be fixed at different fastening points of the stretcher, and a rope assembly to connect the lifting gear with a lifting device, wherein the rope assembly includes a set of rope sections, each rope section having a fixed length and a first end being connectable to the lifting device and an opposite second end being connectable to the first end of any other rope section or to the lifting gear.

Abstract: A tread support device for stairways is generally triangular with two parts which pivot in relationship to one another to allow selection of any desired riser height. Precalculated groups of holes on each of the two parts overlap, with different sets of holes overlapping at different riser heights separated by different increments of ? inch. An alignment guide allows easy selection of the desired riser height, after which the holes which are aligned and overlapping are fastened together to keep the device whole. A complete system consists of left-handed and right-handed tread support units, along with right and left handed units designed to meet the base of the steps with adjustable bolts. A stairway may be built using uncut stringers by use of the invention.

Abstract: A ladder for a fire truck includes a plurality of telescoping ladder-frame sections, each formed of a pair of spaced side rails having a C-shaped cross section for slidably receiving a corresponding side rail on an adjacent section. Positioned between each of the side rails are a plurality of motorized platforms that are deployable to provide a series of horizontal stairs for ascending the ladder. The platforms may also be inverted until they are parallel with the side rails to form a slide on which a fire victim may easily descend to safety.

Abstract: Disclosed herein is an adjustable staircase wherein each tread of the staircase is suspended from a tread adjustment mechanism. The tread adjustment mechanism allows the coordinated movement of all the treads to a desired rise height, and allows the positioning of the first tread directly on a supporting surface when it is in a fully lowered position.

Abstract: A tool for use with elevators and escalators, having two or more slidably connected assemblies, is provided. The assemblies have rails connected together and arranged in a parallel orientation. Support members are connected to the rails and a plurality of treads is attached to the support members. The treads are configured to provide a working surface upon which personnel can stand, sit or kneel and upon which materials can be placed. An extension member is connected to one end of the rails. Each extension member includes a locking member and a stop. Each locking member includes a first arm, a second arm and a third arm. In an open position, the third arm is in contact with the stop and in a closed position, the second arm is in contact with the stop. The assemblies are configured to bridge gaps formed within and around the elevators and escalators.

Abstract: A lift apparatus configured to move a passenger platform of the lift apparatus between a first position and an elevated second position. A stairway of the example lift apparatus may be used as a stairway when the passenger platform is arranged in the first position. As the passenger platform is raised to the elevated second position, hinged steps of the stairway are transformed into a horizontal surface.

Abstract: A tool for use in the construction and maintenance of elevators and escalators is provided. The tool includes a plurality of rails arranged in a parallel orientation, a plurality of support members connected to the plurality of rails and a plurality of treads attached to the plurality of support members. The plurality of treads is configured to provide a working surface upon which construction or maintenance personnel can stand, sit or kneel. The plurality of treads is further configured to provide a working surface upon which materials can be placed. The tool is configured to bridge gaps formed within the elevators and escalators and bridge gaps formed in building spaces in and around the elevators and escalators.

Abstract: The present invention involves a selectively collapsible ladder which permits for adjusting the pitch of the steps between at least two pitches, one pitch being where the ladder collapsed for storage and another pitch whereby the steps are positioned for use by a user. The ladder includes a support structure comprising one or more support rails for extending between the ground and a loading or work surface or storage compartment. The steps are connected together by one or more links for effecting simultaneous movement of the steps. A stop mechanism is provided to releasably fix the step pitch relative to a support rail. The stop mechanism may include a ratchet mechanism that permits setting the pitch of the steps at one of several available pitch settings.

Abstract: A convertible dock ramp has an upper end pivotally mounted to a mounting structure, and a lower end resting on a second structure. The dock ramp includes a pair of spaced-apart side frames each including upper and lower rails; and a plurality of steps each including a tread surface and a bottom surface connected by spaced-apart curved front and rear surfaces. The steps are pivotally mounted between the side frames such that the tread surfaces remain substantially parallel to each other as the side frames pivot. The steps are pivotable between: a ramp configuration in which the tread surfaces collectively form a flat ramp surface; and a stair configuration in which the tread surfaces collectively form a staircase-like structure. A changeover mechanism selectively retains the convertible dock ramp in the ramp configuration or the stair configuration.

Abstract: A convertible dock ramp has an upper end for being pivotally mounted to a mounting structure, and a lower end for resting on a second structure. The convertible dock ramp includes a pair of spaced-apart side frames each including upper and lower rails; and a plurality of steps each including a tread surface. The steps are pivotally mounted between the side frames such that the tread surfaces remain substantially parallel to each other as the side frames pivot about the upper end. The steps are pivotable between: a ramp configuration in which the tread surfaces collectively form a substantially flat ramp surface; and a stair configuration in which the tread surfaces collectively form a staircase-like structure. A changeover mechanism selectively retains the convertible dock ramp in the ramp configuration or the stair configuration. A safety stair tread deflects upward as needed to prevent trapping a user's foot.

Abstract: A pivot assembly particularly adapted for pivotally interconnecting a pair of relatively thin parallel walls spaced an appreciable distance from one another. A stud with a pivot joint on one end is interposed between the walls.

Abstract: The invention is a loading system, which is a combination adjustable height stairway and a landing platform at one end that can be elevated to the level of the aircraft loading door and a lifting portion for loading articles to and from the landing platform. Both the lifting portion and the adjustable height stairway are side by side and are adapted to move in unison to and from the aircraft and further adapted to independently elevate or descend. The stairway and lifting portion may each be independently operated by at least one hydraulically driven motor. The system can moved to and from the aircraft using a combination of independent drive wheels and swivel wheels in order to provide tight maneuverability of the combined stairway and lifting portion.

Abstract: A flexible, waterproof flashing is described. The flashing contains a base layer containing at least one synthetic fiber layer and at least one metal layer; and an adhesive layer located above the base layer, wherein a portion of the adhesive layer is capable of contacting with a substrate.

Abstract: An elevator in which the sheave diameter is reduced and the attendant lowering of the rope life and strength is suppressed to secure safety and reliability. To this end, a rope is used in which a plurality of element wires constituting the wire rope are each covered with resin material and the whole wire rope is covered with resin material, thereby reducing the wear due to slippage between the element wires and the wear due to contact with the sheave, which wear occurs when the rope is entrained around the sheave. When the elevator sheave diameter is reduced, a worried lowering of the rope life can be suppressed or the rope life can be improved. Thus, it is possible to achieve reduction of size and weight of equipment including motors and hoists, installation space saving for elevators, improved safety and reliability of the system by virtue of the increased rope life.

Abstract: A portable embankment stairway with steps that can be adjusted for the slope of the section of the embankment on which it is temporarily installed to provide level footing for workmen on the stairway.

Abstract: A bulk unloading station is formed by two elongated modules stacked one on top of the other. Each module has a frame with pillars and when the upper module is stacked on the lower module the pillars on the upper module align with the pillars on the lower module. The modules are sized for shipment by truck or railroad car to the bulk unloading site. The lower module contains fluid transfer equipment. Unloading arms, with fluid conduits connectable to a fluid containing vehicle at one lateral side of the station, are mounted on the upper module. Conduits extending between the lower module and the upper module include removable segments at the juncture of the modules.

Abstract: An adjustable stair stringer and railing construction assembly is disclosed. The assembly is adapted to use a pair of parallel stringer arms for each side of the stair, a riser/tred support bracket for each stair, and alignment and spacing elements for spacing the support brackets along the stringers. The brackets include formations for spacing the stringers with respect to each other and for spacing adjacent brackets along the stringers. The brackets are initially pivotally attached to each of the stringers so as to be rotatably movable about their pivotal attachment as the stringers are moved axially. Axial movement of the stringers with respect to each other establishes the angle of rise of the stair. Treds and risers are attached to the brackets to form the stairs and railings are attachable to the stringer and bracket assembly to complete the construction.

Abstract: A gangway to accommodate passage to and from a boarding structure includes first and second longitudinal frame members each having an elongate housing with a wall structure surrounding an interior thereof and a pair of longitudinal elongate rails extending through a length of the housing in parallel relation to each other and terminating at opposite distal ends; the pair of rails including a fixed rail and a moving rail. A series of step members, each including top bottom step surfaces, are rotatably supported between the first and second longitudinal frame members in pivotal interconnection with the pair of rails of each frame member.

Abstract: A gangway to accommodate passage from one floor, platform level, deck surface, or the like to another includes a rigid support structure defining a main frame assembly having a pair of longitudinal frame members extending in spaced, parallel relation to one another substantially along a length of the main frame assembly between opposite ends. A series of step members, each including a substantially flat top step surface, are supported transversely between the longitudinal frame members in close relation to one another; each of the step members being rotatable relative to the main frame assembly about a transverse axle.

Abstract: A stairway connects a stationary member, such as a fixed dock, to a member, such as a floating dock or a floating vessel, which moves vertically with respect to the stationary member. The stairway moves with the moving member and includes stringer members connected to hand rail members by picket members and step supporting pivot arms connected to adjustment arms in a manner which forms a compound parallelogram linkage in which the picket members and the pivot arms remain vertical during movement of the stairway whereby the steps remain horizontal and the hand rails remain parallel to the stringer members during such movement. The stairway includes wheels that rollably engage the moving member and moves between angular orientations as the moving member moves with respect to the stationary member. Steps are mounted on the pivot arms and include walking surfaces which remain horizontally oriented during movement of the stairway.

Abstract: An upstanding support structure is provided defining an elevated horizontally elongated stationery platform extending along one side of the support structure and a horizontally elongated second platform is mounted, in cantilever fashion, from the one side of the support structure for vertical shifting relative thereto so as to be downwardly displacable over the upper portion of an elongated bulk material receiving vehicle disposed along side the one side of the support structure adjacent the lower end thereof. The second platform includes a first side fence extending along the side thereof adjacent the support structure as well as end fences extending across the ends of the second platform and appreciably outwardly beyond the outer side of the second platform.

Abstract: The invention is an adjustable height stairway having two parallel elongate ower frame members and two parallel elongate upper frame members swingable on a base. The upper frame members have wave-like edges that can fit with complimentary wave-like edges on the lower frame members. A set of steps parallel to the base has pivotal connections to each frame member at peaks of the wave-like edges. At a first angular position, the stairway is in a collapsed configuration wherein the pivotal connections are coplanar and the steps lie in a common plane to form a runway. In a second angular position the stairway is in an expanded configuration form a ladder or set of stairs.

Abstract: An upstanding support structure is provided defining an elevated horizontally elongated stationary platform extending along one side of the support structure and a horizontally elongated second platform is mounted, in cantilever fashion, from the one side of the support structure for vertical shifting relative thereto so as to be downwardly displaceable over the upper portion of an elongated bulk material receiving vehicle disposed along side the one side of the support structure adjacent the lower end thereof. The second platform includes a first side fence extending along the side thereof adjacent the support structure as well as end fences extending across the ends of the second platform and appreciably outwardly beyond the outer side of the second platform.

Abstract: The side ladder has upper and lower footpaces (1, 3) connected with side elements (5) on which a flight of steps (7) is hinged. A first actuator (11) is provided for withdrawing the ladder from a housing (15) on the boat and a second actuator (13) is provided for rotating the ladder about a horizontal axis. A leverage (21, 23, 27, 29) keeps the steps (7) and the lower footpace (3) in their horizontal position during rotation of the ladder. A piston and cylinder system (53) is provided for operating a handrail (41) and a further rotation of the ladder about a vertical axis can be carried out by a hydraulic motor (31).

Abstract: An adjustable stairway is disclosed that is supported on a retractable, wheel mounted carriage. A locking mechanism selectively maintains the carriage in a lowered, ground engaging position for easy maneuvering of the stairway. The weight of the stairway urges the carriage into a raised position when the locking mechanism is released, allowing the stairway to rest on stationary foot pads.

Abstract: An elevated platform is provided including one longitudinal marginal portion alongside which an elongated tank body of a vehicle may be disposed. The marginal portion of the platform pivotally mounts a pair of extension panels therefrom in slightly spaced relation therealong for movement between raised inoperative positions and downwardly and outwardly inclined operative positions and a step ramp has one end pivotally mounted from the platform between the panels for swinging movement between a raised inoperative position and a downwardly and outwardly inclined inoperative position. The outer margins of the panels and the outer end of the step ramp are generally coterminous when in the operative positions for engagement with and support from the near side of the top of a tank body and an upstanding railing assembly is swingably mounted from the platform and positionable for engaging and the support from the far side of the top of a tank body with which the panels and the ramp are engaged.

Abstract: Adjustable staircase having a pair of stringers each provided with a pair of pantographs, disposed one above the other, identical in overall length and having diagonal levers also of equal length, which levers are pivoted at their center and end points. The ends of the pantographs are mounted to connectors that are intended to be fixed to the two different levels that are to be joined. This mounting is such that the ends of the two pantographs, at each level, can pivot about axes that lie in horizontal planes so that if the levels to be connected are moved away or toward one another, corresponding pivot points on the two pantographs move together in parallel horizontal pivot points planes. The threads of the staircase are fixed to the pantographs by means of supports each of which has a tread portion which is secured to one edge of one tread and a pantograph portion which is pivotally connected to corresponding pivot points lying in the same horizontal plane.

Abstract: This invention relates to a platform and more particularly to a vertically adjustable safety platform assembly for obtaining safety railing enclosed access to the tops of mobile equipment of various heights such as tank trucks and railroad tank and hopper cars. The assembly includes an elevated platform portion for obtaining access to the tops of mobile equipment, and a ladder for obtaining access to the platform. The platform is mounted on a column on guide rails, such platform being power driven by controls either from below or from the platform. The platform includes safety railings along the perimeter of the platform which extend beyond the perimeter so that when the platform is positioned on top of the mobile equipment a safety railing enclosure is provided.

Abstract: A rocker arm assembly for support of the haul rope of an aerial tramway or the like is disclosed. The assembly includes rocker arms, rope supporting sheaves rotatably mounted to the rocker arms and cantilevered from an inwardly facing side of the rocker arms. The rocker arms are additionally formed with rope catching groove or recess positioned outwardly of the sheaves and having a configuration which will enable not only the rope, but a hanger arm and grip to pass over the rope catcher in the event that the haul rope derails from the sheaves. The rocker arm assembly also preferably includes a platform which acts as a mount for the rocker arms and can be used for maintainence and repair of the rocker arms and rope supporting sheaves. Additionally, the rocker arm assembly includes haul rope derailment responsive apparatus formed to shutdown the tramway operation upon derailment of the rope from the sheaves.

Abstract: In a stepladder, with two legs which are connected with each other swingably around an axis in the region of an upper end of the legs, at least one of the legs has transverse support members which are supported by a first pair of stiles, and arranged spaced apart from each other in the longitudinal direction of the first pair of stiles to form the treads, said transverse support members being developed as board-shaped threads which, when the legs are spread apart a predetermined maximum distance, the standing surface of the transverse support members is horizontal and lies in horizontal planes, the treads being connected swingably about axes parallel to each other, to the first pair of stiles and to respective link members which are parallel to the first pair of stiles whereby a mutual supporting relationship between the first pair of stiles and the link members upon a predetermined maximum spread of the legs so as to increase the resistance to bending of the first pair of stiles and limit the swingability of