57 results about "Fixed ladder" patented technology

The utility model discloses a roadway drainage pipeline water leakage on -line monitoring devices relates to monitoring device technical field, including setting in the mounting bracket of groove upper end still include: swing rod sensor, set in mounting bracket upper end, elastic card piece, set in the fixed ladder type bottom plate of groove inboard upper end, when the water flow of groove inboard has the flow, the water flow extrusion is connected on the V type tab of ladder type bottom plate upper end, and V type tab pushes its front end fixed extrusion rod, and extrusion rod extrusion pushes elastic card piece and the water baffle bottom part of swing rod sensor one side set swing rod lower end and separates, and then through the water baffle drive swing rod sensor rotates to make sensor transmission signal alarm, and the device can detect the water leakage condition fast and accurately, and timely sends out the alarm signal, and lets the maintenance personnel know and handles the problem in the first time, and effectively avoids the problem such as roadway ponding caused by not finding in time because of water leakage.

The utility model relates to the technical field of automobile production equipment, in particular to an automatic nail feeding device for an automobile production line. According to the technical scheme, the automatic nail feeding device comprises a stepped nail feeding machine, a plurality of movable stepped plates and a plurality of fixed stepped plates which are arranged in the stepped nail feeding machine in a staggered mode and further comprises a feeding bin formed in the stepped nail feeding machine, and an adjusting baffle is slidably connected to the interior of the feeding bin; and a step mechanism is arranged at one end, close to the movable step plate and the fixed step plate, of the adjusting baffle. The adjusting baffle, the telescopic mechanism and the sliding mechanism are matched, the hand-cranking handle is rotated to drive the screw rod to drive the adjusting baffle to move horizontally, the step plate is clamped through the step mechanism, the telescopic elastic rod abuts against the step plate, and the using length of the step plate can be adjusted according to the length of a screw. In this way, the problem that a fixed-length step plate is poor in adaptability is solved, long screws are prevented from being stuck, short screws are prevented from laterally turning and sliding out, conveying interruption is reduced, and the screw conveying efficiency is improved.

This utility model discloses a lifting platform, including a fixed ladder and a base. The fixed ladder is welded to the upper surface of the base, and a sliding ladder is slidably connected to the outside of the fixed ladder. Slide grooves are formed in the support rods on both sides of the sliding ladder, and sliding rods with sliding rollers are provided on both sides of the sliding ladder. A transmission mechanism is provided on both sides of the fixed ladder, and the transmission mechanism includes several guide wheels set on the slide grooves. A steel wire rope is placed in the grooves of the guide wheels. A lifting mechanism is provided on the upper surface of the base, located below the sliding ladder, with one end of the steel wire rope fixed to the lifting mechanism. This utility model, by setting up a lifting mechanism, allows the lifting platform to slide smoothly within the slide grooves using the sliding rollers on the slide rods. Combined with the steel wire rope and guide wheels in the transmission mechanism, and the lifting mechanism itself, this achieves smoother lifting and lowering of the work platform, making the lifting process smoother and more stable. It effectively avoids shaking and jamming, greatly improving work efficiency.

The utility model discloses a hanging folding ladder for hanging a wall, which comprises a pair of L-shaped supports arranged in parallel at intervals, each support comprises a wall connecting section extending horizontally and an extending part connecting section extending vertically, one end of each wall connecting section is connected with a cantilever wall, and one end of each extending part connecting section is connected with an extending part of the cantilever wall; the limiting groove is formed in the wall connecting section; the folding ladder comprises a main ladder section and an auxiliary ladder section which are connected through a hinge, and a bearing cross rod at the top of the main ladder section is hung on the wall connecting section in a sliding mode and can fall into the limiting groove along the wall connecting section in a sliding mode. The ladder can be installed at a fixed position, the problems that the ladder is privately moved and cannot be found in emergency situations are solved, the ladder can be folded and lean against the wall at the fixed position, the occupied space is reduced, and the problem that a traditional fixed inclined ladder occupies a channel and a goods area is solved.

The utility model discloses a scaffold for indoor decoration, and relates to the technical field of indoor decoration. The device comprises a fixing frame, two sides of the fixing frame are rotatably matched with fixing ladders, the lower sides of the two fixing ladders are slidably matched with extension ladders, cushion blocks are arranged at the bottoms of the extension ladders, adjusting assemblies are arranged between the fixing frame and the cushion blocks on the two sides, and storage boxes are installed on the outer side edges of the fixing frame and the two extension ladders. The height of the scaffold can be conveniently and rapidly adjusted through the adjusting assembly, different decoration height requirements are met, the fixed ladders on the two sides of the fixed frame can be rotationally unfolded around the fixed rods, the extension ladders can be slidably unfolded on the lower sides of the fixed ladders, the bottoms of the extension ladders are supported through cushion blocks, and unfolding of the scaffold is completed. After construction is finished, the extension ladder can slide back into the fixed ladder, the fixed ladder rotates around the fixed rod to be folded, storage is convenient, the storage box is installed on the outer side edge of the scaffold, and constructors can conveniently take and place tools and materials at any time.

The utility model relates to a folding type pedal ladder, it includes fixed ladder, fixed block, movable ladder, special-shaped pin shaft and baffle, is fixed with fixed block respectively in the top rear side of two vertical rods of fixed ladder, has the foldable movable ladder through special-shaped pin shaft swing joint in the middle part of fixed ladder, is fixed with baffle respectively vertically in the both sides of the bottom of fixed ladder behind movable ladder, when movable ladder unfolds, the board surface of movable ladder and baffle abuts, is opened in the top of two vertical rods of fixed ladder along the left and right direction respectively and is passed through and has been connected the slot, two joint slots are opposite settings, when movable ladder is completely folded, the crosspiece of movable ladder is placed in the joint slot.

A system is provided for safe access to a roof through an opening in a roof of a structure having a fixed ladder leading upward to the opening. The system includes a mechanism to drive a set of pushrods to raise a hatch covering the opening. The system may include a section of ladder secured to the underside of the hatch. The system may have an extendable ladder driven by the drive mechanism to slide along the fixed ladder and extend through the opening in the roof when the hatch is raised. The system may include a safety pole driven by the drive mechanism to extend through the opening in the roof when the hatch is raised. The system allows someone who needs to access the roof for inspection or maintenance to safely open the hatch, climb up through the opening in the roof, and safely step onto the roof.

The utility model belongs to a ladder stand device in constructional engineering, and particularly relates to a telescopic ladder stand which comprises a fixed ladder fixed on the upper portion of a structure, the fixed ladder is composed of a plurality of ladder steps, a telescopic ladder is arranged on the outer sides of the ladder steps, the telescopic ladder comprises a sliding rail and ladder plates, the sliding rail adopts two U-shaped steel channels, notches of the U-shaped steel channels are oppositely arranged, and the U-shaped steel channels are fixedly connected to the two sides of the outer ends of the ladder steps; the ladder plate comprises two stand columns, the two stand columns are connected through a plurality of step beams, and the stand columns are installed in the U-shaped channel steel in a sliding mode; a plurality of grooves are symmetrically formed in the side outer wall of the stand column, each groove is provided with a deepest point, and the deepest points and the outer wall of the stand column are in inclined plane connection; a roller assembly is arranged on the outer side of the groove and fixedly connected with the sliding rail through an elastic mounting seat, and a roller is clamped in the groove through a spring to play a role in preventing the extension ladder from falling.

An emergency evacuation device of a wave-compensated gangway comprises a first horizontal moving frame, a second horizontal moving frame and a fixed truss, one end of the first horizontal moving frame and one end of the second horizontal moving frame can slide up and down along the fixed ladder end support, the other end of the first horizontal moving frame is sleeved with a first sliding block, the first sliding block can slide along the axial direction of the first horizontal moving frame, the other end of the second horizontal moving frame is sleeved with a second sliding block, the second sliding block can slide along the axial direction of the second horizontal moving frame, the first sliding block and the second sliding block are fixed on the wave-compensated gangway, the two ends of the fixed truss are connected with the first horizontal moving frame and the second horizontal moving frame respectively, a movable truss is arranged between the fixed truss and the wave-compensated gangway, and the end of the movable truss is connected with the first horizontal moving frame through a hinge. The design can reliably connect the ladder and the wave-compensated gangway, and ensure that the operating personnel can evacuate from the wave-compensated gangway in the case of wave-compensated gangway failure.

The utility model provides a ladder cage prefabricated foundation which comprises a concrete prefabricated slab, and the concrete prefabricated slab is provided with a foundation fixing structure used for fixing the concrete prefabricated slab on the ground and a ladder cage fixing structure used for fixing a ladder cage on the concrete prefabricated slab. The elevator cage connecting structure comprises a metal connecting block used for being welded to the elevator cage body and an elevator cage connecting threaded column poured on the concrete prefabricated plate, and the elevator cage connecting threaded column penetrates through the metal connecting block and then is in threaded connection with an elevator cage connecting nut so that the metal connecting block can be fixed to the concrete prefabricated plate. The utility model aims to provide the removable ladder cage prefabricated foundation for fixing the ladder cage, and solves the problems that the installation speed is slow and waste pollution is generated as the foundation needs to be manufactured on site when the existing ladder cage is used.

The utility model relates to the field of bar feeding, and discloses an automatic distributing feeder which comprises a bar box, the bottom of the front side wall of the bar box is fixedly communicated with a conveying channel, and the bottom of the bar box and the bottom of the conveying channel incline forwards and downwards. Supporting legs are fixedly connected to the two corners of the bottom of the rear side of the bar box and the two corners of the bottom of the front side of the conveying channel, the upper portion and the lower portion of the front portion of the conveying channel are open, two fixed ladder plates are fixedly connected between the rear end of the bottom opening and the front end of the top opening of the conveying channel and distributed in a left-right spaced mode, and sliding grooves are formed in the front side and the rear side of the outer wall of each fixed ladder plate. A lifting ladder is arranged between the two fixed ladder plates, the left side and the right side of the lifting ladder are in sliding fit with the two fixed ladder plates, the left side wall and the right side wall of the lifting ladder are each fixedly connected with two fixed shafts, and the four fixed shafts are located in the four sliding grooves correspondingly. The lifting ladder is driven by the air cylinder to move up and down in a reciprocating mode, and therefore automatic distribution and feeding of bars are achieved.

The application provides an adjustable boarding ladder, and relates to the technical field of marine equipment, which comprises a frame structure and a support column structure, the support column structure comprises a support cylinder and a movable column, and a rotary control device is arranged at the connection between the support cylinder and the movable column; the frame structure comprises a first platform and a second platform, one side of the first platform is provided with a movable ladder frame, the upper end of the movable column is provided with a lifting piece for controlling the lifting and falling of the movable ladder frame; one side of the second platform is provided with a fixed ladder frame, a climbing channel is arranged between the first platform and the second platform, an escape channel is arranged below the second platform, a pawl limiting device is arranged outside the support cylinder and between the first platform and the second platform, and the pawl limiting device is used for limiting the rotation of the movable column to ensure the safety of escape; the boarding ladder adopts a double-layer structure, the first platform is communicated with the second platform through the climbing channel, when congestion occurs on the second platform, personnel can be distributed through the escape channel, and the occurrence of trampling can be effectively reduced.

The invention discloses a sliding ladder stand adaptive to multiple working conditions. The sliding ladder stand comprises a fixed ladder fixed to a mechanical equipment rack and a movable ladder arranged on the fixed ladder. Clamping grooves with different heights are formed in the movable ladder, and the length of the movable ladder downwards extending out of the bottom of the movable ladder is adjusted by clamping the movable ladder in the clamping grooves with different heights. The passing performance of machine construction is improved, and the user can get on and off the vehicle conveniently.

This utility model relates to the field of pressure vessel technology, specifically disclosing a mobile pressure vessel ladder, including a base with casters at the lower end and support studs on both sides. A support frame is located at the upper end of the base, with an inclined fixed ladder connected to one side of the support frame. A lifting platform is located above the support frame, with a vertical ladder connected to one end of the lifting platform. Lifting frames are connected to both sides of the vertical ladder, and the lifting frames slide against the support frame. The upper end of the lifting frames is connected to the bottom of the lifting platform, and the other end of the lifting platform is connected to a telescopic platform. In use, the telescopic platform rests on the maintenance platform on top of the pressure vessel. This utility model reduces the risk of equipment failure throughout its entire lifecycle, extends its safe service life, has extremely high utilization, and is convenient and flexible to use. Compared with existing technologies, this device reduces manufacturing and maintenance costs.

1. The name of the design product: ladder universal fixed connecting piece. 2. The use of the design product: used for connecting and fixing ladder assembly through three joints. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: perspective view.

The invention relates to an electric steel tube combined tower and a mounting method thereof, the electric steel tube combined tower comprises a steel tube tower body with a fixed ladder, an electric rope ladder winding and unwinding assembly is arranged in an inner cavity of the steel tube tower body, and the steel tube tower body is further provided with a rope ladder inlet and outlet. The electric rope ladder winding and unwinding assembly is arranged in the inner cavity of the steel tube tower body, a gear motor of the electric rope ladder winding and unwinding assembly can be prevented from being exposed to wind, rain and the sun, the outdoor service life of the gear motor is greatly prolonged, after the rope ladder is wound, the cover plate covers the rope ladder inlet and outlet, and the rope ladder winding and unwinding effect is improved. In this way, irrelevant personnel cannot touch the electric retractable rope ladder assembly, the irrelevant personnel can be prevented from manually damaging the electric retractable rope ladder assembly, a very good anti-climbing effect can be achieved for the irrelevant personnel, after the rope ladder is unfolded downwards, a maintainer can conveniently climb the rope ladder, the use reliability is very high, and the electric retractable rope ladder assembly is suitable for popularization and application. By arranging the clamping supporting part and the anti-swing inserting part, when the rope ladder is used by a maintainer, the rope ladder does not swing, and the rope ladder has enough supporting force and is more reliable to use.

The utility model provides a tower buckling rod piece installing and hanging platform which is installed on a tower frame cross rod and comprises a crawling ladder, the crawling ladder comprises two vertical pipes which are arranged in a mirror image mode, and a plurality of bearing cross rods are arranged between the two vertical pipes in the length direction of the two vertical pipes. The two U-shaped frames are arranged at the two ends of the two vertical pipes respectively, clamped to the corresponding tower cross rods and used for fixing the ladder stand between the two adjacent tower cross rods; and the construction platform is arranged between the two vertical pipes. A constructor can enter the construction platform through the crawling ladder formed by the cross rods and the two vertical pipes, the construction platform is fixed between the two tower cross rods under the action of the two U-shaped frames, the constructor can stably operate on the construction platform, the risk of high-altitude operation is reduced, and meanwhile the construction efficiency is improved. And the crawling ladder, the U-shaped frame and the construction platform can be quickly assembled, so that the construction period is greatly shortened, and the construction efficiency is improved.

The utility model discloses a portable platform ladder which comprises a platform, and guardrails are detachably connected to the two side edges of the platform in the length direction. The two ends of the platform in the length direction are detachably connected with a left side ladder and a right side ladder respectively, the left side ladder and the right side ladder comprise fixed ladder sections which are located on the upper portions and detachably connected with the platform respectively, the lower portions of the fixed ladder sections are connected with telescopic ladder sections, and telescopic locking devices are arranged between the fixed ladder sections and the telescopic ladder sections. When the portable platform ladder is used, the guardrails on the platform can be detached firstly, the platform ladder crosses the handrails between the roads or between the bridges from the road or the bridge on one side, the platform ladder is erected between the roads on the two sides or between the two bridges, the guardrails are assembled on the platform after adjustment, and at the moment, the portable platform ladder is constructed. A worker can easily and quickly walk to a road or a bridge on the other side from the platform by crossing a handrail in the middle of the road or the bridge from the road or the bridge on one side, so that the rescue time is greatly shortened.

The utility model relates to the technical field of square-cone mixers, and discloses a square-cone mixer convenient to feed, which comprises two mounting racks, a square-cone mixer body is rotatably arranged in the middle of the two mounting racks, a blanking protection mechanism is fixedly arranged at the lower end of the square-cone mixer body, a fixed ladder is fixedly arranged on one sides of the two mounting racks, and the fixed ladder is fixedly arranged on the other sides of the two mounting racks. A feeding mechanism is fixedly arranged on one side of the fixed ladder, the discharging protection mechanism comprises a mounting ring, telescopic rods are fixedly arranged at the lower ends of the two sides of the mounting ring, a corrugated pipe is fixedly arranged in the middle of the lower end of the mounting ring, and the feeding mechanism comprises a mounting block. According to the feeding device, the feeding mechanism is arranged, through cooperation of a servo motor, a threaded rod, a threaded box and other components, a discharging box can be lifted to the height aligned with the upper end of the fixed ladder, a worker can conveniently carry materials to a feeding port, the labor intensity of manual carrying is reduced, and the feeding efficiency is improved.

A vehicle-mounted telescopic ladder, relating to the field of telescopic ladder technology, includes components such as a fixed ladder, an extension ladder, and a wear-resistant sliding plate. The fixed ladder has two spaced-apart poles and multiple crossbars. The extension ladder has two C-shaped poles that movably fit over the fixed ladder poles, and also includes multiple crossbar assemblies. The wear-resistant sliding plate is installed at the four corners of the fixed ladder poles, with its surface and end face corresponding to the inner wall of the extension ladder poles. Positioning pin holes on the plate surface mate with through holes at the top of the extension ladder, used to install positioning pins to restrict relative movement. The fixed ladder pole has an upper limit seat and a first lower limit baffle. The extension ladder pole has a second lower limit baffle at its inner top. The extension ladder pole has feet with rubber pads. The fixed ladder has a hook at the top, and the extension ladder has an anti-slip pad at the bottom. This invention allows the fixed ladder and extension ladder to slide with zero gap, reducing noise and improving the user experience.

1. Name of the designed product: ladder fixing connector. 2. Use of the designed product: used for connecting and fixing ladder assembly through interface. 3. Design points of the designed product: in shape. 4. Picture or photo showing the design points: perspective view.

A ladder assembly is disclosed that is configured for use with a vehicle. The ladder assembly includes a case and a ladder defining a longitudinal axis. The case include at least one engagement member that is configured for releasable engagement with the vehicle such that the ladder assembly is removably connectable thereto. The ladder is reconfigurable between a collapsed configuration and an expanded configuration and is pivotably connected to the case to allow for adjustment in an angular orientation of the ladder. In certain embodiments, the ladder assembly may further include one or more locking mechanisms that are configured to fix the angular orientation and / or the vertical position of the ladder.

The utility model provides a kind of welding tool of ladder stand, comprising: multiple positioning plate are equipped and are all installed on bottom plate, a part of positioning plate is placed transversely, another part of positioning plate is placed longitudinally, the positioning plate of transverse placement is used to fixed the riser of ladder stand, the positioning plate of longitudinal placement is used to fixed the horizontal pipe of ladder stand;Support plate is installed on bottom plate and is used to fixed the L-shaped plate of ladder stand;Positioning plate and support plate mutually cooperate, form the working position for fixing each component of ladder stand.The utility model has the beneficial effects: through positioning plate and support plate, the fixing of riser and horizontal plate is completed and the L-shaped plate for fixing ladder stand is welded on ladder stand, simplifies the process of assembly, facilitates the welding of staff, and guarantees the stability of welding, improves welding quality.

1. The name of the design product: ladder universal fixed connecting piece. 2. The use of the design product: used for connecting and fixing ladder assembly through two rotating interfaces. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: perspective view.

The utility model relates to the technical field of ice makers, and particularly discloses a structure for conveniently and quickly disassembling a skating plate, which comprises a fixed side plate, an in-out limiting groove is formed in the fixed side plate; an opening hole is formed in the in-out limiting groove; a stepped shaft is rotationally inserted into the opening hole; when the stepped shaft rotates in the opening hole to the upper limit groove and the clamping protrusion to be aligned and overlapped, certain friction force is generated, the angle between the stepped shaft and the movable block is fixed, and therefore the locking function is achieved. The in-and-out limiting groove can be opened and closed by rotating the movable block, when the upper limiting groove and the clamping protrusion are staggered by rotating the movable block and the in-and-out limiting groove is opened, the limiting shaft and the skating plate can be assembled and disassembled through the in-and-out limiting groove, and when the upper limiting groove and the clamping protrusion are aligned and coincident by rotating the movable block, the limiting shaft and the skating plate can be assembled and disassembled through the in-and-out limiting groove. When the in-and-out limiting grooves are closed, the limiting shafts and the skating plates are closed in the in-and-out limiting grooves, and meanwhile rotation of the limiting shafts and the skating plates is not affected for skating.

The invention discloses a bearing device suitable for an exoskeleton, which comprises an exoskeleton machine armor for improving the load bearing capacity of a user, a bearing assembly arranged on the back of the exoskeleton machine armor and comprising a tool frame for placing small parts and a tool back frame for bearing large tools, a loading and unloading piece used for connection is arranged between the tool frame and the exoskeleton machine armor, the tool back frame comprises two supporting rods parallel to one side of the tool frame, and bearing rods are fixedly installed between the supporting rods and the tool frame. The exoskeleton machine armor has the beneficial effects that through the design of the tool frame and the tool back frame, a worker can conveniently carry various tools used in electric power overhaul in a severe environment through the exoskeleton machine armor, in addition, through the splayed design of the two supporting rods, the worker can conveniently fix ladders of different specifications on the tool back frame, and the working efficiency is improved. And the application range of the tool back frame is expanded.

The utility model relates to the technical field of building construction, in particular to a building climbing frame for constructional engineering. The technical problem to be solved by the utility model is to provide a building climbing frame for constructional engineering. The building climbing frame comprises a base, a fixed ladder frame, a connecting cross rod, a first sliding ladder frame, a second sliding ladder frame, a fixed sleeve, a clamping rod, an elastic piece and the like, a fixed ladder assembly is hinged to the upper portion of the base and is in sliding connection with one side of a first sliding ladder assembly, the other side of the first sliding ladder assembly is in sliding connection with a second sliding ladder assembly, and the fixed ladder assembly, the first sliding ladder assembly and the second sliding ladder assembly are all provided with connecting transverse rods at uniform intervals. Fixed sleeves are arranged above the fixed ladder assembly and the first sliding ladder assembly, clamping rods are sleeved with the fixed sleeves, and elastic pieces are clamped between the fixed sleeves and the clamping rods. According to the telescopic climbing frame, the fixed ladder assembly, the first sliding ladder assembly and the second sliding ladder assembly are connected with one another, so that the effects that the climbing frame stretches out and draws back, and the length of the climbing frame is increased are achieved.

The utility model discloses a kind of vehicle-mounted emergency box-type substations, belong to box-type substation technical field, it includes substation box, the substation box side is provided with fixed assembly, the substation box side is fixedly connected with guide rail, slidingly connected with moving frame on the guide rail.The utility model is provided with fixed assembly, it is convenient to vertically fix ladder, is stored in the substation box side, vertically stored ladder is firm and does not shake, when reaching emergency site, staff can quickly unlock fixed assembly, put down ladder and carry out operation, be provided with guide rail, moving frame, ladder, cylindrical rack, protective cover one, connecting block two, box door and transmission assembly, when moving frame drives ladder to slide on guide rail, cylindrical rack of moving frame side drives transmission assembly in protective cover one to work, so that the connecting shaft on protective cover one rotates, connecting shaft is opened by connecting block two with box door, without again operating box door alone, greatly save time and energy.

The utility model provides a carriage structure of a power supply semitrailer, which comprises a tractor, a gooseneck semitrailer and a carriage, stress grooves are arranged on two sides of the front portion of the carriage, each stress groove is in a groove shape and consists of an outer groove plate, a framework and an inner decorative plate, a folding top climbing ladder is further embedded in each stress groove and comprises a fixed ladder and a folding ladder, and the fixed ladders and the folding ladders are arranged on the framework. The fixed ladder is fixedly installed in the stress groove, and the bottom of the fixed ladder is connected with the folding ladder in a turnover mode. According to the utility model, the groove is additionally arranged at the joint of the gooseneck semitrailer and the carriage, the groove plays a role of a stress concentration venting port, the structure is simple, and the processing cost is low; the folding top climbing ladder is additionally arranged in the groove, so that after the tractor is separated from the semitrailer, the top climbing operation is not influenced, and an operator can normally go to the top of the vehicle to maintain the vehicle.

The present application relates to the field of airport ground equipment, in particular to a wide range of passenger elevator car telescopic structure ladder body, including fixed ladder, telescopic ladder and ladder telescopic oil cylinder, also including telescopic assembly; telescopic assembly includes telescopic tail ladder, pedal mounting bracket, bottom support and elastic member, pedal mounting bracket is slidably connected with telescopic ladder through elastic member, bottom support is fixedly connected with fixed ladder, telescopic tail ladder is fixedly connected with pedal mounting bracket, when telescopic ladder is lowered to the lowest, telescopic ladder drives pedal mounting bracket to abut against bottom support, at this time, pedal mounting bracket and telescopic tail ladder are limited and lifted by bottom support, steps of telescopic tail ladder are compressed and close to the fixed step below the lowest step of telescopic ladder, at this time, elastic member is stretched and stored energy, when telescopic ladder is pushed out by ladder telescopic oil cylinder and linear displacement is generated with fixed ladder, telescopic tail ladder is pushed out by gravity and elastic member until the limiting position, reaches the same height difference and depth position as other fixed steps.