Abstract: The deploying stepway includes a guide frame and a step assembly. The step assembly includes a plurality of steps, a step frame pivotally coupled to the steps and including a pivot assembly, and a proximal portion and a distal portion defined on either side of the pivot assembly. The deploying stepway is configured to transition among a stair configuration, in which the proximal and distal portions are aligned and extend from the guide frame at a declined stair angle, a ladder configuration in which the distal portion is pivoted relative to the proximal portion and extends from the guide frame at a declined ladder angle, and a stowed configuration in which the step assembly is at least substantially received in the guide frame. The methods include deploying the deploying stepway from the stowed to the stair configuration and transitioning the deploying stepway from the stowed to the ladder configuration.

Abstract: Vacuum cleaning devices include foldable wands to provide a storage configuration and/or facilitate use. A vacuum cleaning device includes a wand having a first end coupled to a vacuum unit and a second end coupled to a vacuum head or surface cleaning head. The wand defines an air passage allowing air to pass from the surface cleaning head to the vacuum unit and includes a flexible air passage along at least a portion of the wand. The wand also includes a plurality of segments pivotably connected together such that the wand is foldable about 180° in a forward direction until the vacuum unit is positioned proximate a top of the surface cleaning head, thereby providing a storage configuration.

Abstract: A tree stand includes a ladder portion having first and second rails, a tree-engaging member configured to engage a tree, and a mechanism being selectively variable in length operatively interconnecting the member and the first and second rails and controlling the distance between the member and the first and second rails. A platform is pivotably connected to the first and second rails.

Abstract: A stake post having a locking hinge that enables selective movement of a gate unit between a first position in which the gate unit forms a portion of a retaining wall in cooperation with other gate units, and a second position in which the gate unit is removed from alignment with one or more adjacent gate units to thereby provide an opening through a retaining wall otherwise formed by the stake post when in the first position.

Abstract: This disclosure relates to accessories configured to be supported by door strikers of motor vehicles. In particular, the accessories may be mounted to a motor vehicle when a traditional, or factory, door is removed. Some example accessories are useable as a step when mounted to the vehicle, and are also useable as a tool (i.e., as a shovel, flashlight, bit driver, socket wrench, and/or hex wrench) when removed from the vehicle.

Abstract: A disclosed rebar coupler includes a first coupling member, a second coupling member, and a coupling means. Accordingly, the connection angle between the first coupling member and the second coupling member is variable to a desired angle. The connection angle between rebars to be connected may be rapidly and conveniently varied at an industrial site to which the rebars are applied.

Abstract: An emergency descent system includes at least one ladder which is articulated on at least one supporting unit on a bearing device. The ladder is designed to be unfolded about this bearing device out of a rest position in which the ladder is disposed parallel to the at least one supporting unit and into a working position, wherein a push-out unit and a pivot unit operatively connected thereto by means of a catch are associated with the ladder. The pivot unit drives the push-out unit by the kinetic energy generated during the unfolding, wherein the push-out unit moves away from the at least one supporting unit at a first acute angle, and in the operating position, the push-out unit forms an acute angle with the at least one supporting unit and the pivot unit is held at an obtuse angle relative to the push-out unit on a stop associated with the at least one supporting unit.

Abstract: A fall protection tool for use in blocking an opening in a doorframe. The tool includes a frame assembly including a pair of lateral posts spaced from each other and extending substantially parallel with each other, and at least one transverse post extending between the pair of lateral posts. The tool also includes a hook member coupled to each lateral post, wherein the hook member is configured to couple to a portion of the doorframe such that the frame assembly is hangable from the doorframe.

Abstract: The present invention relates to an integrated folding safety handrail and outdoor escape stairs for high-rise buildings and an emergency escape device which are applied to high-rise buildings such as safety handrails for preventing falling from a movable passage exposed to apartment houses such as apartments or office buildings, and the outside and is applied as a substitute for safety handrails in high-rise buildings or outdoor ground clearance 3 m or more which is usually used as a safety handrail for falling prevention and so that an escaping person in the high-rise building escapes outside or safely escapes to a lower floor in case of emergency such as fire, terror, and disaster.

Abstract: The present invention relates to at least a foldable step mounted within a cabinet or cupboard of varying heights and having a minimal folded profile. The foldable step has a pair of cross members secured in a horizontal orientation to the cupboard. The cross members are coupled to a pair of cupboard support members. The cupboard support members are rotatably coupled to two offset members that rotate vertical support members to reach the floor. The vertical support members hold a plurality of steps using other support members. The entire linkage structure pivotally or slidably folds into a minimal profile.

Abstract: A clamping system for supporting an extension ladder on a gutter utilizes at least one and, more preferably, a pair of identical, clamp(s) to capture the ladder preventing movement laterally or horizontally away from the gutter. The clamp includes a clamp body with a latch pivotably mounted thereto which is spring biased to the gutter-clamping position. A lock screw may be utilized to prevent the latch from releasing the gutter preventing the ladder from moving. A pair of ears extends from each side of the clamp body and have slots which engage the channels on a forward face of the ladder leg.

Abstract: A ladder in a multi-step structure includes: first front and rear connecting members that are connected to a vehicle body and between a wheel and an end of the vehicle body and that are juxtaposed with a predetermined space; a first step board that is connected between respective lower ends of the first front and rear connecting members; second front and rear connecting members, respective upper ends of which are connected to both ends of the first step board; and a second step board that is connected between respective lower ends of the second front and rear connecting members. In the first front and rear connecting members, one near the wheel is fixed to the vehicle body and the other near the end of the vehicle body is connected in a pivotally movable manner to the vehicle body and is foldable.

Abstract: The current invention provides an automatic gear-shift drive mechanism including a first gear system having a first gear ratio, and a second gear system having a second gear ratio, wherein the first gear ratio is higher than the second gear ratio, and is biased to spin the drying assembly with the first gear system when the automatic gear-shift drive mechanism is driven and the workload is below a threshold workload, and switch to spin the drying assembly with the first and the second gear systems when the automatic gear-shift drive mechanism is driven and the workload is at or above the threshold workload.

Abstract: A roof ladder construction includes a roof hook assembly and a ladder to which the roof hook assembly is pivotally mountable for movement between two operative positions, a first of the operative positions being a position in which the roof hook assembly may extend over a roof ridge for engagement with a remote roof surface at a side of the roof opposite that at which the ladder is positioned and the other, second position being one in which the roof hook assembly does not engage with the remote surface of the roof.

Abstract: Latching or locking deployment hinges are provided that include a latch mechanism, a spring-loaded tensioning device, and a trigger mechanism. The trigger mechanism and the spring-loaded tensioning device are configured to transfer the compressed spring load in the spring-loaded tensioning device to the latch mechanism once the hinge has closed sufficiently far enough to latch together, thus inducing a pre-load through the latch mechanism that eliminates gapping in the hinge interface. The hinges may be sprung or actuated using a powered drive mechanism.

Abstract: A hatch actuating arrangement for actuating a hatch of a hatch device, with the hatch device being adapted to be disposed or being disposed within a tower structure of a wind turbine. A hatch actuator being movably supported relative to the hatch such that a downward force upon the hatch actuator and a weight of the hatch actuator urges the hatch to rotate toward the open position; and wherein the hatch actuator is connected to and positioned proximate a side of a ladder above the hatch so that a user may open the hatch while upon the ladder above the hatch.

Abstract: Self-locking bi-foldable load bearing segments are disclosed that can be used in applications such as ladders or ramp. First and second sections of the segment are foldably coupled to transition between an open configuration and a folded configuration. The first and second sections can include rungs pivotally attached to rails that can be further transitioned from the folded configuration to a collapsed configuration, but not transitioned from the open configuration to the collapsed configuration. Openings in the side walls of the rails allow the rungs to pivot in one direction, but not an opposite direction. In the open configuration, the openings of the first and second sections may be oriented opposite, and the direction of allowed rotation of the rungs of the first section and second section are opposite, restricting compression of the rails together.

Abstract: A foldable ladder has multiple ladder segments that fold and unfold relative to each other. Each ladder segment includes one rung element and multiple side rail sections that unfold for deployment to form box-shaped side rails of the ladder. Adjacent ladder segments are connected to each other by hinge joints. The ladder includes locking features at the hinge joints for preventing relative pivoting movement of adjacent ladder segments by more than about 180 degrees.

Abstract: A climbing support is provided for aiding a climber in scaling a tree, pole, or other generally vertical surface. The climbing support includes an elongate body that supports a plurality of steps, a strap, cable, or other flexible securing member that is wrapped around the tree, and a retractor for stowing the flexible securing member so that it is extendable and retractable from the support. The climbing support is thus substantially self-contained so that it does not require separate components for installation or use. Standoffs may be provided for stabilizing the support in a location spaced from the tree. Optionally, the climbing support's steps, standoffs, and elongate body are collapsible to compact configurations for stowage or transport.

Abstract: Self-locking bi-foldable load bearing segments are disclosed that can be used in applications such as ladders or ramp. First and second sections of the segment are foldably coupled to transition between an open configuration and a folded configuration. The first and second sections can include rungs pivotally attached to rails that can be further transitioned from the folded configuration to a collapsed configuration, but not transitioned from the open configuration to the collapsed configuration. Openings in the side walls of the rails allow the rungs to pivot in one direction, but not an opposite direction. In the open configuration, the openings of the first and second sections may be oriented opposite, and the direction of allowed rotation of the rungs of the first section and second section are opposite, restricting compression of the rails together.

Abstract: A convertible ladder and scaffold assembly includes a plurality of uprights and a plurality of beams each extending from one of the uprights. A plurality of hinges each hingedly connect one of the uprights to one of the beams about a rotational axis (AR) to provide an assembly having ladder, scaffold, push-cart, and storage configurations. Each of the hinges defines catches and present a stop releasably engaging catches for preventing rotation about the rotational axis (AR). At least one lever bar releasably engages a plurality of the stops for simultaneously releasing a plurality of the stops from engaging catches. Each of the lever bars have a plurality of lever sections for providing leverage to disengage the stops from the catches. Each of the lever bars has a grip section interconnecting the lever sections for simultaneously releasing a plurality of the stops from engaging the catches.

Abstract: A safety equipment deployment system includes a sensor for receiving input, circuitry for determining whether the input satisfies a time pattern requirement and, responsive to determining satisfaction of the time pattern requirement, triggering release of safety equipment. The safety equipment can include a foldable ladder fixed to a stanchion. The safety equipment can include a device attached to a cord that extends from a bobbin below deck, through a hollow stanchion, and out a top end of the stanchion.

Abstract: Ladder configurations and components are provided including an outer rail assembly which is longitudinally adjustable relative to an inner rail assembly. The outer rail assembly may include a pair of spaced apart outer rails each fixedly coupled to an associated sleeve or sliding mechanism. Each sleeve is in turn slidably coupled to an inner rail of the inner rail assembly. The outer rails may be positioned and oriented at an acute angle relative to the inner rails so as to provide an increased base distance between the two outer rails. Support structures are also disclosed which are coupled at multiple locations along a rail member and at least one location of a rung. Additionally, ladder hinges are disclosed including hinge components configured to effectively transmit loads from associated rails. In one embodiment the hinge may include a pinch prevention mechanism.

Abstract: The present disclosure relates to a step stool, and particularly to a folding step stool including legs that fold between an opened, use position and a collapsed, folded position. The present disclosure also relates to a tray assembly that moves relative to the legs and is used for storing or holding articles associated with use of the step stool. The step stool includes a mechanism to coordinate the movement of the tray assembly and a step of the step stool when the step stool is moved between the opened and collapsed positions.

Abstract: A collapsible work horse has legs pivotally mounted to opposing surfaces of a support beam. The legs are secured in the extended position by a two-part locking arrangement. In one non-limiting embodiment of the invention, a first part of a locking arrangement is mounted to each of the first ends of the legs adjacent the pivot point of its respective leg, and a second part of the locking arrangement is mounted to the supporting member. When the legs are in the extended position, the first and second parts of the locking arrangement engage one another to securely fix the legs in the extended position. In another non-limiting embodiment of the invention, a plurality of work horses are assembled with a tool support and work piece supports to provide a work station. The tool support and work piece supports are designed to be fixable in a compact storage arrangement.

Abstract: A universal hinged tread system includes a folding stair set with one or more primary treads. At least one auxiliary tread is hingedly attached atop at least one primary tread. The folding stair set includes at least two hingedly attached sections. The hingedly attached sections fold flat against each other when in a stowed position, and every other folding stair section is inverted when in the stowed position. Each auxiliary tread is angularly displaced from its primary tread as its folding stair section is inverted. The auxiliary treads do not obstruct any primary treads on other sections when in a stowed position. The auxiliary treads include a beveled lower front edge to aid the auxiliary treads in deflecting.

Abstract: A boarding ladder includes an upper step having a first and second collar, a lower step having a left and right side selectively slidably engaged with the first and second collar, respectively, with the lower step selectively slidable between raised and lowered positions. Left and right extensions are pivotally engaged with the left and right sides, respectively, with the left and right extensions pivoting between folded and extended positions. The left and right extensions are selectively slidably engaged with the first and second collars, respectively, in the extended position. A method of lowering a boarding ladder includes pivoting a left and right extension of a lower step to an extended position, disengaging a retention member from an upper step and the lower step, and lowering the lower step from the upper step until a stop on each of the left and right extensions abuts the upper step.

Abstract: Ladder configurations and components are provided including an outer rail assembly which is longitudinally adjustable relative to an inner rail assembly. The outer rail assembly may include a pair of spaced apart outer rails each fixedly coupled to an associated sleeve or sliding mechanism. Each sleeve is in turn slidably coupled to an inner rail of the inner rail assembly. The outer rails may be positioned and oriented at an acute angle relative to the inner rails so as to provide an increased base distance between the two outer rails. Support structures are also disclosed which are coupled at multiple locations along a rail member and at least one location of a rung. Additionally, ladder hinges are disclosed including hinge components configured to effectively transmit loads from associated rails. In one embodiment the hinge may include a pinch prevention mechanism.

Abstract: A folding ladder includes a hinge assembly having first and second ladder hinge plates each defining a plate opening and a plurality of locking slots. A housing is associated with the first ladder hinge plate and extends through the plate openings to provide a rotation axis for the plates, and the second plate is operable to rotate relative to the first plate about the rotation axis to selectively align slots of the first and second plates. A key outside the housing selectively engages aligned slots to selectively prevent rotation of the ladder hinge plates about the rotation axis and is operated by a manual rotation member. An extension ladder includes a pair of nested outer and inner ladder rails. Ladder rungs connected between and the inner rails define a plurality of supporting openings and the inner rails include outer bearing surfaces associated with the supporting openings.

Abstract: Ladder configurations and components are provided including an outer rail assembly which is longitudinally adjustable relative to an inner rail assembly. The outer rail assembly may include a pair of spaced apart outer rails each fixedly coupled to an associated sleeve or sliding mechanism. Each sleeve is in turn slidably coupled to an inner rail of the inner rail assembly. The outer rails may be positioned and oriented at an acute angle relative to the inner rails so as to provide an increased base distance between the two outer rails. Support structures are also disclosed which are coupled at multiple locations along a rail member and at least one location of a rung. Additionally, ladder hinges are disclosed including hinge components configured to effectively transmit loads from associated rails. In one embodiment the hinge may include a pinch prevention mechanism.

Abstract: A walking ladder which has a pair of ladder sections each section having a pair of spaced apart elongated members and a series of steps spaced apart and extending across the space between the elongated members. A pair of hinges are provided with each hinge pivotally coupling corresponding ends of the elongated members so that said sections have an A-shape when in an operating position. The hinges are confined to a width bounded by sides of the elongated members. A user straddles the walking ladder and removes his/her weight from one step and transfers it to another enabling the user to move one section of the ladder relative to the other and hence walk.

Abstract: The invention provides aluminum ladder hinge with enhanced safety structure. The hinge is made of flat inner case and outer case. Especially, the hinge has a locking block design to stabilize the angle of opening and closure. There is also a design of a joint reinforcing disk and a reinforcing tab to enhance the guiding groove and reduce friction loss. There is also design of prolonged caps and a rectangular hole, liner to strengthen the assembly of the hinge and the aluminum ladder. Based on the above designs, an advanced aluminum ladder hinge with enhanced safety structure is invented to improve the safety of aluminum ladder in use.

Abstract: An articulated joint for a foldable ladder includes an outer casing pair, an inner casing pair pivotally moving with respect to the outer casing pair, a lock device composed of a lock block and a locating pin. The locating pin has a ball end to be slightly squeezed in the locating hole such that the ball end is capable of retained in the locating hole and pivotally joined to the locating hole. The lock block provides triangular prism shaped projections at two opposite long edges of the bottom side of the lock block. Hence, the lock block can move along the guide slot of the outer casing shells steadily and be pivotally joined to fixing pin without loosening apart from each other.

Abstract: A folding step stool includes a hinge mechanism. The step stool includes a first section connected to the hinge mechanism. The first section having a bottom step. The step stool includes a second section connected to the hinge mechanism. The step stool includes a third section connected to the hinge mechanism, wherein when the folding step is in and unfolded state, the first and second sections form a base on a floor and are in angular relationship with each other, and the third section extends upward from the hinge mechanism relative to the first section, and when the first, second and third sections are in a folded state, they are essentially in parallel with each other, are no more than ¾ as tall and ½ as long as when the step stool is in the unfolded state. A method for using a folding step stool. A hinge for a folding step stool having a folded and unfolded state and having a top rail, front rail and rear rail. A method for using a folding step stool.

Abstract: A dynamic hinge includes a first member connected to a first ladder portion of a ladder, and a second member connected to a second ladder portion. The first member pivots relative to the second member about a pivot axis that does not intersect both the first and second members. The first member includes first and second parallel segments, and the second member includes a third and fourth parallel segments. A guide plate is attached to either the first or second member, and the guide plate is positioned between the first and second segments and between the third and fourth segments. The guide plate includes two non-linear slots, and an other of the first and second members includes two pins, respectively adapted to slide within the two non-linear slots. The pins extend between either the first and second segments or the third and fourth segments.

Abstract: A ladder having a first ladder section, a second ladder section, an adjustable hinge mechanism, an engagement indicator and a static hinge mechanism. The adjustable hinge mechanism is mounted with respect to the first ladder and the second ladder so that the adjustable hinge mechanism is moveable between an engaged position and a disengaged position. The static hinge mechanism enables the first and second ladder sections to be maintained in a stationary position with respect to each other.

Abstract: A hinge for a folding ladder including a hinge latch movable between a locked position and an unlocked position disposed within a hinge latch cavity. The hinge latch includes a first locking portion protruding therefrom, an elongated slot formed configured to slidingly receive a hinge shaft, a first opening configured to receive a first biasing member, and a second opening configured to receive a locking member. Rotational movement of one hinge casing relative to another hinge casing is prevented by engagement of the first locking portion and locking member with a respective one of the first opening and second opening.

Abstract: A collapsible handrail mechanism for steps or a ladder including: an outer stringer and an inner stringer jointly pivotable about a pivot point; a stanchion located between the outer and inner stringers and pivotally mounted to at least one of the stringers; a latching mechanism through which the stanchion passes and to which at least one of the stringers is pivotally mounted at the said pivot point; the latching mechanism having a slide plate preventing substantial downwards movement of the stanchion, a top plate preventing substantial upwards movement of the stanchion, and a side plate preventing substantial sideways movement of the stanchion; whereas, in operation of the handrail mechanism from a stowed position, when the stringers are lowered the stanchion is thereby forced to slide on the slide plate causing the stanchion to pivot about its mounting up into an operational position.

Abstract: A lockable hinge includes a first and second hinge member, a lock, and an actuator. The lockable hinge is coupled to a pair of ladder-leg sections and is arranged to allow the ladder-leg sections to move among closed-ladder, trestle-ladder, and straight-ladder positions. The lock is used to lock the hinge members to cause the ladder-leg sections to lock in the closed-ladder, trestle-ladder and straight-ladder positions.

Abstract: A system and method for providing an improved ladder for enabling a user to climb up or down and forward or backwards movement relative to a surface. The system enables increased mobility and stability. The system can be designed in multiple ways which some of them have been shown in the present invention. The present invention clearly saves production time, keeping the user on the ladder while relocating, and it definitely more convenient and time saving to the user.

Abstract: The present invention teaches a boat trailer ladder which may be easily secured to and moved along the trailer rails. A hook is dimensioned and configured to engage standard boat trailer rails. An A-frame ladder provides steps from an approximately the level of the trailer rails, or in alternative embodiments from approximately ground level, up for a distance above the trailer rails. The extra elevation gained by a user of ordinary size standing on an upper step is sufficient to allow them to reach the top surfaces of the boat.

Abstract: A folding step stool includes a hinge mechanism. The step stool includes a first section connected to the hinge mechanism. The first section having a bottom step. The step stool includes a second section connected to the hinge mechanism. The step stool includes a third section connected to the hinge mechanism, wherein when the folding step is in and unfolded state, the first and second sections form a base on a floor and are in angular relationship with each other, and the third section extends upward from the hinge mechanism relative to the first section, and when the first, second and third sections are in a folded state, they are essentially in parallel with each other, are no more than ¾ as tall and ½ as long as when the step stool is in the unfolded state. A method for using a folding step stool. A hinge for a folding step stool having a folded and unfolded state and having a top rail, front rail and rear rail. A method for using a folding step stool.

Abstract: A lockable hinge includes a first and second hinge member, a lock, and an actuator. The lockable hinge is coupled to a pair of ladder-leg sections and is arranged to allow the ladder-leg sections to move among closed, trestle-ladder, and straight-ladder positions. The lock is used to lock the hinge members to cause the ladder-leg sections to lock in the closed, trestle-ladder and straight-ladder positions.

Abstract: Disclosed herein is a hinge for a folding ladder having first and second ladder frames. The hinge includes a main hinge unit, a subsidiary hinge unit, and a locking unit. The main hinge unit includes first and second support arms commonly mounted to an upper end of the first ladder frame, and first and second disc parts extending from upper ends of the first and second support arms, respectively, and being spaced apart from each other by a predetermined interval. The subsidiary hinge unit includes a subsidiary support arm mounted to an upper end of the second ladder frame, and a subsidiary disc part extending from an upper end of the subsidiary support arm, the subsidiary disc part being disposed between the first and second disc parts, with a plurality of notches being provided along a peripheral edge of the subsidiary disc part.

Abstract: Disclosed herein is a safety unit of a hinge for a folding ladder to prevent a user's finger from being caught in the hinge when the hinge rotates. The hinge includes a first joint unit, a second joint unit, and a locking unit, and the safety unit is provided between a first stop shoulder of the first joint unit and a second stop shoulder of the second joint unit. The safety unit includes a mount part and an insert part. The mount part is provided in the first joint unit to be positioned under the first stop shoulder, and an inside portion of the mount part is rounded to surround a part of the first joint unit. The insert part extends from an upper end of the mount part, and is rounded to have the same curvature as the inside portion of the mount part.

Abstract: A hinge and locking assembly includes a first support plate, a second support plate coupled to the first support plate for pivoting movement about an axis, a knob rotatable about the axis and a rotation limiter. The knob is movable axially along the axis between a first axial position and a second axial position The second support plate has a first tab-receiving space. The knob has a second tab-receiving space. The rotation limiter includes a slip disc rotatable about the axis and having first and second tabs. The first tab moves into the first tab-receiving space when the knob is moved from the first position to the second position. The second tab is received in the second tab-receiving space.

Abstract: A folding ladder includes a hinge assembly having first and second ladder hinge plates each defining a plate opening and a plurality of locking slots. A housing is associated with the first ladder hinge plate and extends through the plate openings to provide a rotation axis for the plates, and the second plate is operable to rotate relative to the first plate about the rotation axis to selectively align slots of the first and second plates. A key outside the housing selectively engages aligned slots to selectively prevent rotation of the ladder hinge plates about the rotation axis and is operated by a manual rotation member. An extension ladder includes a pair of nested outer and inner ladder rails. Ladder rungs connected between and the inner rails define a plurality of supporting openings and the inner rails include outer bearing surfaces associated with the supporting openings.

Abstract: An extension ladder and tree stand for supporting a seated or standing person on an elevated platform against a tree trunk for hunting, photography, and the like. The ladder and platform collapse into a compact size and shape for carrying by a person. The ladder is in telescoping sections. Alternate steps of the ladder slide to the middle of each telescoping section. This provides twice as many steps as sections, reducing the number of telescoping sections by half. This minimizes weight, size, complexity, and expense. When deployed, all parts remain safely assembled in all positions. Captive spring loaded pins fix the telescoping sections in extended or retracted positions, and fix the sliding steps in a middle position of each section. A folding seat on the platform has a cushion that reconfigures into a back cushion for carrying the collapsed assembly on the back of a person.

Abstract: A ladder assembly includes two symmetric support stands pivotally connected with each other. Each of the two support stands includes a main frame, an upper frame, a lower frame, a top bar, a retraction control unit, and four fixing devices. Thus, height of the ladder assembly can be adjusted easily and conveniently, thereby facilitating the user operating the ladder assembly. In addition, the upper frame and the lower frame can be folded on the main frame, so as to reduce the volume the ladder assembly efficiently, thereby greatly facilitating storage and transportation of the ladder assembly.

Abstract: A ladder having a first ladder section, a second ladder section, an adjustable hinge mechanism, an engagement indicator and a static hinge mechanism. The adjustable hinge mechanism is mounted with respect to the first ladder and the second ladder so that the adjustable hinge mechanism is moveable between an engaged position and a disengaged position. The static hinge mechanism enables the first and second ladder sections to be maintained in a stationary position with respect to each other.