131results about "Movable tracks" patented technology

The invention discloses a rail train gravity energy storage system which comprises a low-position storage yard, a high-position storage yard, a transport train, a train rail, a driving device, a power generation device and a transfer device. The train track comprises an upward track, a high-position running track, a downward track and a low-position running track which are sequentially connected to form an annular track; a height difference exists between the low-position storage yard and the high-position storage yard; the ascending rail is provided with an ascending section, the ascending section ascends step by step at the altitude, the multiple driving devices are arranged along the ascending section at intervals, and the distance between any two adjacent driving devices is smaller than or equal to the train length of the transport train. The descending rail is provided with a descending section, the altitude of the descending section is decreased step by step, the multiple power generation devices are arranged along the descending section at intervals, and the distance between any two adjacent power generation devices is smaller than or equal to the train length of the transport train. According to the rail train energy storage system, by arranging the ascending section ascending step by step and the descending section descending step by step, the operation stability and the operation efficiency of the whole system can be improved.

The utility model discloses a kind of across shaft portal crane combined track beam structure, including the reinforced concrete track beam of ground part;Combined track beam across shaft part, the combined track beam is composed of custom steel box girder and the reinforced concrete track beam arranged thereon;Custom steel box girder is connected with enclosure structure by pre-embedded steel plate, and its top elevation is flush with the top elevation of the reinforced concrete track beam of ground part;Combined track beam and the reinforced concrete track beam of ground part are connected, form continuous portal crane track support structure;The device solves the problem that the track beam cannot be set on the ground due to the limitations of site or the width and span of foundation pit in the prior art;It has the characteristics that large-diameter circular shaft portal crane track beam can be arranged across shaft.

The invention relates to the field of railway tracks, and provides a walking track of a fine adjustment system and the fine adjustment system. A walking track of the fine adjustment system comprises a beam assembly, a walking track assembly and a lifting walking arm assembly, the beam assembly and the track panel are arranged at intervals, and an elevation fine adjustment device and a transverse fine adjustment device are arranged on the beam assembly. The walking rail assembly is arranged on the elevation fine adjustment screw and extends in the length direction of the track panel, the lifting walking arm assembly is connected between the beam assembly and the walking rail assembly, the lifting walking arm assembly and the walking rail assembly are movably matched, and the beam assembly can move on the walking rail assembly through the lifting walking arm assembly. The walking rail assembly extending in the length direction of the track panel is arranged on the elevation fine adjustment screw, so that the beam assembly is prevented from walking on the track panel through the lifting walking arm assembly.

The present application relates to the technical field of conveying trolley, in particular to a flexible adjustment motion track conveying trolley for crack detection and an adjustment method thereof, comprising: a track part, comprising a first track and a second track arranged in parallel, the first track and the second track are connected and fixed through assembling supports at both ends, and the assembling supports are provided with steel bridge fixing members for fixing the whole track part on the surface of a steel bridge; a trolley part, comprising a trolley main body, the bottom of the trolley main body is provided with a magnetic slide seat and a driving wheel in sliding fit with the first track and the second track; the top of the trolley main body is provided with a moving seat capable of moving perpendicularly to the length direction of the track, and the moving seat is provided with a holder mounting rack; the second track is provided with at least one additional seat capable of sliding along the length direction and fixed, and the additional seat is provided with a flexible adjustment track structure; the flexible adjustment track structure comprises an assembling pipe and unit seats arranged in the assembling pipe; the purpose of adjusting the motion track and flexibly conveying the detector is achieved.

The invention discloses an installation method and installation equipment for a steel coil trolley track. The installation method comprises the steps that measurement data of a rolling line datum point are obtained through a laser tracker arranged at a target position, and measurement data of a plurality of peripheral position points in the middle of a mandrel are obtained through the laser tracker arranged at the target position; establishing a three-dimensional coordinate system according to the measurement data of the rolling line datum point; performing circle fitting according to the measurement data of the plurality of peripheral position points, and determining the center point coordinate of the central part of the mandrel in the three-dimensional coordinate system according to the fitting result; and target position coordinates used for installing the steel coil trolley track are determined in the three-dimensional coordinate system according to the center point coordinates, and the steel coil trolley track is installed according to the target position coordinates. The technical problems that an existing method for installing the steel coil trolley track is large in error, tedious in operation and long in installation time consumption are solved.

The invention discloses a kind of frame beam soil covering equipment, including support plate (1), the front side of support plate (1) is equipped with two parallel climbing tracks (2), and climbing track (2) is equipped with climbing guide groove (5), and the lower end of climbing track (2) is hinged with support plate (1), and transport vehicle (3) is equipped between two climbing tracks (2), and the bottom of transport vehicle (3) is equipped with two rows of gyro wheel (4), and two rows of gyro wheel (4) are located in the climbing guide groove (5) of two climbing tracks (2) respectively, and lifting car is equipped with winch mechanism (6) between support plate (1);The lower part of climbing track (2) is equipped with guide rail (7), and guide rail (7) is equipped with guide guide groove (8), and the upper end of guide rail (7) is hinged with climbing track (2).The present application has the advantages of low equipment cost, low use cost and easy to reach the slope position, and good safety, low failure rate.

The invention provides a method for adjusting the length of a main cable by padding sleepers on a ground anchor backpack of a cable system, which comprises the following steps of: establishing a relational expression among the radius of the main ground anchor backpack, the thickness of the sleepers and a cable length adjusting value through analytic geometry, and adjusting the length of the main cable on the premise that the radius of the main ground anchor backpack and the cable length adjusting value are known. The accurate thickness value of the main ground anchor knapsack can be obtained according to the relational expression, in the sag adjusting process of the main cable, the cable adjusting can be completed through quick cushion plugging, repeated operation in the construction process is avoided, and then the construction efficiency can be improved.

The utility model relates to the technical field of explosion-proof ground rails, in particular to an explosion-proof ground rail convenient for dust cleaning, which comprises a ground rail main body, a movable bottom plate is arranged on the ground rail main body, a straight-tooth right-handed gear and a right-handed helical rack which are in meshing transmission are arranged at the bottom of the movable bottom plate, and a vertical plate is arranged at the bottom of the movable bottom plate. A rotating arm and a mounting plate are arranged on the front side plate face of the vertical plate, a connecting arm is rotatably mounted at the end of the rotating arm, a swing arm is rotatably connected to the mounting plate, the movable end of the connecting arm is rotatably connected to the middle of the swing arm, and a mounting support is fixedly connected to the tail end, away from the mounting plate, of the swing arm. According to the explosion-proof type ground rail structure, the cleaning brush which is originally fixedly installed is designed to swing back and forth, in the advancing process of the movable bottom plate, the cleaning brush can synchronously and comprehensively clean dust on the surface of the rack, and the dust cleaning efficiency can be improved.

A walking device for installing equipment in a limited space, comprising a track and a walking device capable of walking along the track, the walking device comprising a main body structure, a guide assembly and an adjustment movement assembly rotatably connected to the main body structure, the main body structure being used for fixing the equipment to be installed, the guide rail being provided with a guide groove in the length direction and a rolling groove on both sides of the guide groove, the guide assembly being rolling fitted in the guide groove and enabling the walking device to move in the length direction of the guide rail, the adjustment movement assembly being rolling fitted in the rolling groove and being used for preventing the walking device from deviating to the sides of the track and derailing, in use, the equipment to be installed is installed on the main body structure of the walking device, the guide rail is installed on the carrier in the limited space, the guide assembly and the adjustment movement assembly can transport the equipment to the position where the equipment needs to be installed in the limited space through the guide rail, and the problem that the equipment cannot be installed and maintained in the later period due to the fact that the equipment installation space does not meet the installation personnel to reach is solved.

The invention discloses a movable track used for a railway wheel set orthogonal to a plate chain and located above the plate chain, which is characterized in that the wheel set, a longitudinal track, a transverse plate chain, a movable track and an orthogonal position are included in a workshop of a railway vehicle depot or a vehicle plant, the wheel set can longitudinally run on the longitudinal track and transversely run on the transverse plate chain, and the movable track can run on the orthogonal position. The orthogonal position is located at the orthogonal position of the longitudinal rail and the transverse plate chain, when the movable rail located at the orthogonal position rides on the transverse plate chain, the wheel pair can stride over the transverse plate chain to move forwards, and when the movable rail is opened or moved away, operation of the wheel pair on the transverse plate chain is not affected.

The present application relates to the technical field of tunnel construction, and discloses a real-time monitoring type three-support structure synchronous construction method The present application aims at solving the technical problems that the track equipment reliability is not high and cannot be replaced in time after the tunnel lining and tunnel excavation are implemented synchronously in the prior art The construction steps of the present application include: tunnel excavation, inverted arch lining processing, inverted arch support lining support, tunnel boring machine tunneling synchronous construction, side top arch lining trolley assembly and displacement The present application realizes synchronous implementation of the tunnel lining and tunnel excavation, reasonably controls the excavation and lining speed, has the advantages of shortening the long and large tunnel construction period, improving the tunnel lining quality, prolonging the track equipment service life and the like ​ ​ ​ ​ ​ ​ ​ 。

The invention discloses a method for transporting a large steel lining to an over-small circular-arch-shaped area in a tunnel. The method comprises the steps that a water blocking ring steel lining is transported to a guide rail area on the upstream side of a small circular-arch-shaped section area of a diversion tunnel through a heavy forklift and unloaded; a binding device of the steel lining and the heavy forklift is dismantled, and the steel lining makes contact with the side guide rail in an inclined mode; pulling the steel lining to slide on the guide rail through a traction assembly to pass through the small arch-shaped section area; and after the traction assembly is removed, the heavy forklift is adopted to load the steel lining again and transport the steel lining to a mounting station. The main function is to adapt to the diversion tunnel which has been supported and is inconvenient to modify and adjust to the greatest extent, the steel lining can be smoothly transported and passed, the transportation safety of the steel lining is ensured, and the controllability of the construction period is also ensured; the method is light and easy to understand, high in practicability, convenient to construct, high in safety coefficient, novel in creativity, reusable and high in generalization performance.

The utility model belongs to the technical field of wharf rail construction, and particularly relates to a plug-in type cross rail, which comprises a main rail, an auxiliary rail, a plug-in type cross rail and a plug-in type cross rail, the center block is composed of a base and an insertion block; the base is positioned below the fracture, and a plurality of jacks are formed in the base; the bottom of the insertion block is provided with an insertion piece corresponding to the position of the insertion hole. According to the utility model, a continuous track is reserved, the operation process is simplified while the impact wear of the travelling crane is reduced, and the device has a better market application prospect.

The utility model provides a bridge crossing device and a transfer device of a railway maintenance vehicle set and the railway maintenance vehicle set. The gap bridge device comprises a swing arm and a clamping plate, the clamping plate is fixed to one end of the swing arm, and the other end of the swing arm is connected with a first transfer device rail. One end of the telescopic piece is connected with the swing arm, and the other end of the telescopic piece is connected with a carriage of the first transfer device rail; the baffle is provided with a clamping groove and is fixed at the end part of the second transfer device track; the telescopic piece extends to drive the swing arm to swing until the clamping plate abuts against the clamping groove of the baffle and reaches preset pressure, the telescopic piece is locked, and the swing arm is connected with the first transfer device rail and the second transfer device rail. The gap bridge device solves the technical problems that a traditional gap bridge device is complex in structure and inconvenient to operate.

This invention provides a vibration-damping and noise-reducing track structure for RGV (Remotely Resistant Vehicle). The RGV vibration-damping and noise-reducing track structure includes: a vibration-damping base; two tracks, which are mounted on top of the vibration-damping base via multiple sets of fixing brackets. Each set of fixing brackets has fixing bolts installed on its top. The vibration-damping base includes a support structure, a vibration-damping structure, and a wear-resistant structure. The wear-resistant structure is installed between the support structure and the wear-resistant structure, and the vibration-damping structure is a rubber damping pad; filling openings are located at both ends of the tracks, and the interior of the filling openings is filled with a filling structure, which is made of foam plastic. Each track has a sliding opening on its top. The vibration-damping and noise-reducing track structure for RGV provided by this invention can effectively isolate vibration transmission between the track and the foundation, reducing ground vibration and noise propagation, reducing ground vibration amplitude by 30%-40%. Simultaneously, the filling structure can absorb noise, improving the noise reduction effect.

The invention discloses a raw material stacker-reclaimer rail horizontal load resisting structure and a construction method. According to the structure, embedded bolts and anchor bolts are arranged in a rail foundation, a rail base plate is arranged on the surface of a grouting layer and fixed through the embedded bolts, and a rail is erected on the surface of the rail base plate and fixed through a rail pressing device; the force transmission plate is arranged on the surface of the resistance component, the resistance component is arranged between the track foundation and the track base plate, the anchor plates are arranged on the two sides of the resistance component and fastened through anchor bolts, the grouting layer is poured around the resistance component, and the track base plate is located on the surface of the grouting layer. The method comprises the following steps: determining the thickness of a resistance component and a force transmission plate according to process requirements, paying off, positioning and mounting embedded bolts and anchor bolts, pouring a track foundation, mounting the resistance component, the force transmission plate, the anchor plate and a track base plate, pouring a grouting layer, and mounting a track through a track pressing device and the track base plate. According to the structure and the construction method, the vertical load of the track is effectively transmitted, the capability of resisting the horizontal load is achieved, the safety and applicability of the track are improved, and potential safety hazards are eradicated.

The utility model discloses a support arm for a track machine, which is mounted on a support and comprises a support body and a connector, the support body is provided with at least two vertical mounting holes, two corresponding side walls of the support body are recessed inwards to form arc recesses respectively, and the arc recesses are positioned in the middle of the center connection of the two vertical mounting holes; at least one transverse mounting hole is formed in the connecting body, and the transverse mounting hole is matched with the mounting seat. According to the supporting arm for the track machine, due to the fact that the multiple vertical installation holes and the one or more transverse installation holes are formed, connection between the supporting arm and the support and connection between the supporting arm and the track are firmer and safer, and due to the design of the connecting plates and the arc concave parts, the overall strength of the supporting arm is further enhanced, and safety is higher.

A mining turnout device based on no movement comprises a mining turnout device body provided with a first stock rail (2), a second stock rail (3), a fourth stock rail (4), a fifth stock rail (5), a sixth stock rail (6) and a seventh stock rail (7), a first butt-joint rail assembly arranged on the first stock rail (2), and a second butt-joint rail assembly arranged on the second stock rail (3). The first butt-joint rail (8) is arranged among the first butt-joint rail assembly, the second butt-joint rail assembly, the fifth stock rail (5) and the sixth stock rail (6), and the turning machine (90) is arranged among the first butt-joint rail assembly, the second butt-joint rail assembly, the first butt-joint rail (8) and the mining turnout device body. The first stock rail (2) is in split rail body butt joint through the first butt rail assembly, the second stock rail (3) is in split rail body butt joint through the second butt rail assembly, the fifth stock rail (5) and the sixth stock rail (6) are in split rail body butt joint through the first butt rail assembly (8), and the fifth stock rail (5) and the sixth stock rail (6) are in split rail body butt joint through the turning machine (90). End head swing motion of the first butt-joint rail assembly and the second butt-joint rail assembly is achieved, middle rotation motion of the first butt-joint rail (8) is achieved, and transposition butt joint of a turnout between two station tracks is achieved through corner motion. The technical problem that the turnout is subjected to transposition butt joint between two station tracks through the displacement motion of the switch machine with thread transmission is solved, so that the installation space of the mining turnout is optimized, and the application range of the mining turnout is expanded.

The invention relates to the technical field of track insulation construction, in particular to an electric flat car track and equipment foundation insulation method. According to the technical scheme, insulating material parameters are matched according to construction environment humidity; and then a multi-layer insulation system is constructed through the four steps that insulation grouting materials are poured into the embedded bolt holes, the top face of the foundation is coated with insulation paint, an insulation cushion leather plate is laid, a rail is installed and fixed through a rubber rail pressing device, and secondary insulation grouting is conducted on the upper portion of the rail. Insulation detection nodes are respectively arranged after track installation and secondary grouting, qualified detection is used as a process conversion condition, and an insulation performance file is synchronously established. Through combination of environment adaptation, multi-layer insulation, process detection and data filing, the problem of low success rate of one-time construction in the prior art is solved, and a systematic, verifiable and full-period controllable insulation construction quality control system is formed.

The present application relates to the technical field of agricultural rail car, and particularly relates to an agricultural rail car track structure, which comprises a track body, two ends of a connecting sleeve are inserted into a first guide rail and a second guide rail respectively; a first bolt hole is arranged on the first guide rail, and a first bolt passes through the first bolt hole and one end of the connecting sleeve; a second bolt hole is arranged on the second guide rail, and a second bolt passes through the second bolt hole and the other end of the connecting sleeve; the second bolt hole is a long strip-shaped through hole, and the length of the second bolt hole is greater than the length of the connecting sleeve inserted into the first guide rail. The present application has the beneficial effects that: in the agricultural rail car track structure, the long strip-shaped second bolt hole is arranged, when disassembling, the second bolt drives the connecting sleeve to completely shrink into the second guide rail, at this time, the first guide rail and the second guide rail are conveniently separated and disassembled, and it is not necessary to be limited to disassembling the head and tail sections, so that the disassembling efficiency of the track is improved, and the track maintenance and replacement are also facilitated.

This invention pertains to the field of pedestrian transportation in coal mine roadways, specifically disclosing an intelligent personnel transportation system for mine roadways. The system includes a track installed at the top of the roadway, with a forward movement device slidably connected below the track. The forward movement device is powered by a drive unit connected below it. An automatic boarding / alighting device is detachably connected below the drive unit. The automatic boarding / alighting device includes a passenger vehicle and a propulsion mechanism for separating / connecting the passenger vehicle and the drive unit. The intelligent transportation system also includes an intelligent allocation system for scheduling the passenger vehicles and automatically navigating routes according to instructions. This intelligent personnel transportation system can transport pedestrians to any designated location in the underground roadway via the track installed at the top of the roadway, allowing for scheduled times and designated routes. The automatic boarding / alighting device overcomes the limitation of not being able to perform other operations while transporting people in the roadway, and features high safety, high intelligence, and high labor efficiency.

The inclined laneway track comprises a sleeper, a steel rail and a connecting plate, fasteners are oppositely arranged at the top of the sleeper, the steel rail is connected to the top of the sleeper and connected with the fasteners in a buckled mode, and the connecting plate is connected with the sleeper and the steel rail. Therefore, connection between the steel rails and the sleepers is firmer, vibration and impact force generated when a mine car runs can be effectively resisted, and relative displacement between the steel rails and the sleepers is reduced, so that the risk of loosening of the rails is reduced, the distance between the steel rails can be kept stable, and change of the distance between the rails caused by connection loosening is avoided; the possibility of mine car derailing is reduced, and transportation safety is guaranteed; meanwhile, the connecting plates can disperse stress at the connecting positions of the steel rails and the sleepers, local damage caused by stress concentration is avoided, and the service life of the rail is prolonged.

A rail system comprising: a first beam and a second beam each comprising a respective upper surface configured to provide a track, a respective pair of sidewalls extending downwards from the respective upper surface and defining a lateral extent of the respective beam, a respective cut-out extending through the respective pair of sidewalls defining a respective cut-out volume extending through the lateral extent of the respective beam and wherein the first beam and the second beam are arranged perpendicular to one another, with the first beam uppermost and the second beam underneath, and the cut-outs of both beams aligned, such that the first beam and the second beam interlock and the first upper surface and second upper surface lie in a single plane, and wherein the rail system comprises a locking arrangement configured to lock the beams together.

The application discloses a kind of multi-track mobile field operation device, by setting up two track bases, a plurality of first tracks, two second tracks, rail car, track car and rail change steering platform etc. Mechanism close cooperation forms a complete operation system on farmland.The rail car carries out linear operation on the first track, solves the problem of poor walking precision and soil compaction of traditional agricultural implements;Track car and rail change steering platform solve the problem of low steering efficiency of traditional operation, realize the quick, accurate transfer and direction adjustment of agricultural implements between different operation lines.Make the whole farmland operation process efficient, accurate, environmental protection, effectively solve the problems of existing technology, such as farmland infrastructure limitation, soil compaction, poor operation accuracy and low steering efficiency.

The utility model relates to the technical field of single crystal silicon rod detection, and provides a gantry type ground rail device for single crystal silicon rod detection, which comprises a ground rail mechanism, a gantry mechanism and a silicon rod rotating table, the ground rail mechanism comprises a base, a sliding rail and a sliding platform. Sliding rails are arranged on the two sides of the base respectively. A rack is arranged on the sliding rail; a sliding platform is arranged on each sliding rail; a servo motor is arranged on the sliding platform; gears are arranged at the output ends of the servo motors, and the gears are meshed with the corresponding racks; the gantry mechanism comprises a mounting plate and two gantry stand columns. The gantry stand columns are arranged on the corresponding sliding platforms, and a mounting plate is connected between the two gantry stand columns. The mounting plate is used for arranging a visual acquisition system; and the silicon rod rotating table is arranged on the base. According to the utility model, the measurement in a full-length range can be realized, and the stability of the visual acquisition system during automatic image data acquisition is ensured.

The invention belongs to the technical field of trolleys, and particularly relates to a low-resistance walking structure of an excavation trolley, which comprises a walking structure mounted at the bottom of a frame, the walking structure comprises steel wheels and rubber wheels which are coaxially fixed, and a flexible steel rail for the steel wheels to walk, and the flexible steel rail is positioned in an accommodating space of a bearing shell; the space between the bottom of the flexible steel rail and the containing space of the bearing shell is filled with a cushion layer, and the space between the cushion layer and the containing space of the bearing shell is filled with a covering layer used for partially burying the flexible steel rail. The diameter of the rubber wheel is larger than that of the steel wheel, when the steel wheel is located on the flexible steel rail, the rubber wheel is suspended, a traditional crawler walking structure is changed into a track walking structure according to local materials used for a gravel pavement and a working environment, and walking resistance during walking can be greatly reduced through track walking; and the problem of frame distortion during walking can be avoided, and the walking stability and the walking speed are remarkably improved.

The utility model belongs to the technical field of tracks, and discloses a dumping plough moving track which comprises a track frame body and a moving bracket, the moving bracket comprises a bracket body, a moving groove, a moving part and a lifting frame, the moving groove is formed in the bracket body, the lifting frame is arranged in the moving groove, the lifting frame is in sliding connection with the moving groove, and the moving part is arranged in the moving groove. The two lifting frames are connected with the track frame body in a clamped mode, and the moving parts are arranged on the lifting frames and used for controlling the lifting frames to move. The rail structure formed by combining the sleeper base and the steel rails is arranged, the high supporting performance is achieved, meanwhile, a downward pressing structure is formed on the two sides of the sleeper base through the arc-shaped pressing blocks and the arc-shaped pressing plates, supporting force can be provided for the sleeper base to avoid settlement of the sleeper base, and when the sleeper base moves, the sleeper base is prevented from falling off. The arc-shaped pressing block and the arc-shaped pressing plate can press the surrounding base material downwards, so that the arc-shaped pressing block and the arc-shaped pressing plate and the sleeper base are kept on the base material.

The present application belongs to the field of track construction technology, especially to a whole turnout reverse curve longitudinal moving steering system and sliding method, which solves the problems of poor anti-overturning ability of the existing whole trolley under strong wind environment, easy to swing tail and hit the tunnel side wall when moving in the narrow tunnel curve, and lack of emergency braking protection when moving on the slope. The system includes turnout and multiple trolley chassis, and the turnout and trolley chassis are provided with a control mechanism, the control mechanism includes multiple slide rods sliding through the trolley chassis, the bottom of the slide rod is rotatably connected with a roller III, the top of the trolley chassis is provided with an anti-overturning mechanism on both sides, the anti-overturning mechanism includes a wind deflector rotating on the top of the trolley chassis and multiple rollers IV arranged below the trolley chassis, and further includes a connecting mechanism for connecting adjacent two trolley chassis, the connecting mechanism includes a rear side plate and a connecting plate fixed at both ends of the trolley chassis, respectively. The present application is used for longitudinal moving steering of the whole turnout under complex line conditions.

The utility model discloses a fastening adjustable fixing device for a large-gradient TBM (tunnel boring machine) inverted arch block rail, which is mounted in a rail bearing groove of an inverted arch block and respectively arranged on two sides of a steel rail in the rail bearing groove, and comprises a first component and a second component, the first assembly is of a box type structure with an opening in one side, one side of the second assembly is installed in the first assembly, the other side of the second assembly is provided with a curved surface matched with the side portion of a base of the steel rail in shape, bolt holes are formed in the top face, the front face and the rear face of the first assembly, and bolts penetrate through the bolt holes. And the fixation of the second assembly is realized. The fastening adjustable fixing device has the advantages that the transverse length of the fastening adjustable fixing device can be adjusted by adjusting the position of the second assembly in the first assembly, the second assembly is fixed through the bolt, and a steel rail on an inverted arch block is fixed.