150results about "Telescopic elements" patented technology

The invention discloses a plane matrix type high folding and unfolding bionic antenna truss structure with a negative Poisson's ratio effect, and relates to the technical field of space folding and unfolding mechanisms, the plane matrix type high folding and unfolding bionic antenna truss structure comprises a plurality of cell elements and a plurality of cell element connecting rods, transverse cell elements are connected through the cell element connecting rods, and longitudinal cell elements are fixedly connected through adjacent cell element cross beams; the cell element connecting rods are hinged to the cell elements on the two sides respectively, and the cell elements are three-level positioning inwards-concave hexagonal cell elements; the folding and unfolding antenna truss structure is in a folded state during launching, transportation and silent latency and is in an unfolded working state during on-orbit task execution, the high folding and unfolding ratio characteristic of the antenna provides bionic improvement inspiration for various urgent properties such as stealth and size reduction of a satellite antenna structure, the shape of the antenna folding and unfolding array can be changed in a multi-stage mode, and the antenna folding and unfolding array is suitable for large-scale popularization and application. Therefore, the functions of optimal frequency band adjustment, optimal area expansion, switching of different scanning ranges and the like are realized.

The invention discloses a mesh antenna metal net zero-constraint splicing method. A metal net is tiled and hung on a working tension applying device, and working tension is applied to the metal net in the transverse direction and the longitudinal direction; in the working tension state, tension control belts are sewn on the edges of the two sides of the metal net in the length direction; lapping two metal nets which need to be spliced and are sewn with the same tension control belts, wherein the sections of the lapping positions are lapped according to the sequence of belt-net-net-belt; sewing two layers of metal nets along the two sides of the tension control belt by adopting composite material sewing lines; and repeating the steps, and sewing all the metal meshes required by the whole antenna reflecting surface in sequence. According to the method, the metal net is spliced by adopting an overlock stitching method, the tension control belt can be detached after splicing is completed, the formed splicing seam is of a net-net structure, the thickness is only 0.07-0.08 mm, the elasticity keeps the original elasticity of the metal net, the net surface tension is more uniform, and the risk that the antenna expansion resistance is increased due to micro shrinkage of the tension control belt at high temperature is effectively eliminated.

The application discloses an over-constrained cross type deployable parabolic cylindrical antenna support structure and particularly relates to the technical field of aerospace. The application comprises a plurality of arc surface deployable units, cylindrical deployable units and a motion control device, the arc surface deployable units are deployed to form an arc-shaped support surface, the cylindrical deployable units are deployed to form a linear support surface, and the motion control device is used for controlling the cylindrical deployable units to drive the arc surface deployable units to be deployed or contracted. The technical scheme of the application aims to provide a reference value for the structural design of a large-scale deployable parabolic cylindrical antenna, realizes the support of the deployable parabolic cylindrical antenna, and is beneficial to the structural design of the deployable parabolic cylindrical antenna.

The utility model discloses an assembly assembly dotting frock, including work table, the top of work table is sequentially provided with feeding station, assembly station, pre -dotting station, dotting station and material collecting box, and the inside of work table is provided with through groove, and one side of through groove is provided with mounting panel, and the top of through groove is provided with material shifting board, and the side of mounting panel is provided with linear slide rail, and material shifting board passes through sliding block and is installed on linear slide rail, and one side of material shifting board is sequentially provided with first material shifting dog, second material shifting dog, third material shifting dog and fourth material shifting dog, and the utility model discloses through with antenna mast from feeding station sequentially after assembly station, pre -dotting station and dotting station, then, fall into the inside of material collecting box, realized the automatic integration of antenna mast feeding, assembly, dotting and collection, reduced the consumption of human resources, improved production efficiency.

The invention discloses a horn antenna device with a reconfigurable wave beam and a using method thereof, and belongs to the technical field of antennae, and the horn antenna device comprises a wave same module which is relatively and fixedly arranged at the tail end of the horn antenna device; the three-axis telescopic framework is connected to the front end of the wave-same module, and the three-axis telescopic framework is at least composed of a transverse electric control telescopic component, a longitudinal electric control telescopic component and a depth direction electric control telescopic component and is used for changing the aperture and the depth size of the horn antenna; the distance feedback device is arranged at the oral surface position of the three-axis telescopic framework and is used for detecting in real time and feeding back the actual oral surface size to the control extension set; and the control extension set is electrically connected with the transverse electric control telescopic component, the longitudinal electric control telescopic component, the depth direction electric control telescopic component and the distance feedback device. The wave beam reconfigurable horn antenna device is simple and small in structure and high in structural strength, can expand various frequency bands and gains, and has high development and use potential.

The application relates to the technical field of aerospace equipment, in particular to a stretchable release mechanism for separating a lunar soil penetration projectile communication antenna, which comprises a main body, the main body comprising a first mounting surface and a second mounting surface, the first mounting surface being arranged obliquely to the second mounting surface; an antenna oscillator arranged on the first mounting surface and provided with a locking ring for locking the antenna oscillator; a super-elastic conductive member sleeved on the second mounting surface; and a fuel line release mechanism arranged on the super-elastic conductive member, one end of the fuel line release mechanism being connected with the locking ring and the other end being connected with one end of the second mounting surface away from the first mounting surface. The arrangement of the fuel line release mechanism avoids the risk of failure of the stretchable release mechanism for separating the lunar soil penetration projectile communication antenna.

An antenna for charging and measurement may comprise: a telescopic support installed at a lower portion of an aerial vehicle and configured to contract when the aerial vehicle lands on a wireless station and extend when the aerial vehicle takes off from the wireless station; and an antenna coil part deformed into a spiral shape when the telescopic support is contracted so that the wireless station receives wireless power and deformed into a conical shape when the telescopic support is extended to measure a radio signal.

The invention discloses a portable frequency interferometer and a wireless signal shielding system. The portable frequency interferometer comprises an interferometer host used for generating a radio interference signal; the at least one antenna assembly is used for transmitting the radio interference signal; and a movable connecting piece. The interferometer host is movably connected with the at least one antenna assembly through the movable connecting piece, so that the antenna assembly can move relative to the interferometer host, and the antenna assembly and the interferometer host can be fixed. According to the portable frequency interferometer, the antenna assembly is movably connected to the interferometer host, integration of the antenna assembly and the interferometer host is achieved, the overall size of the portable frequency interferometer is more compact, miniaturization of the portable frequency interferometer is facilitated, and the appearance of the portable frequency interferometer is simpler and more attractive.

The utility model discloses a posture monitoring communication antenna, which relates to the technical field of communication antenna equipment and comprises a sucker seat, an antenna telescopic rod arranged at the top of the sucker seat, a reflecting plate arranged at the top of the sucker seat, a plurality of reflecting strips matched with the reflecting plate arranged at the top of the reflecting plate, and a connecting rod arranged between the reflecting strips and the antenna telescopic rod. A positioning pin is arranged at the bottom of the reflecting strip, holes matched with the positioning pin are formed in the surface of the reflecting strip and the top of the reflecting plate, the multi-stage telescopic rod serves as an antenna, the length of the antenna can be changed, one side of the antenna is shielded by a housing composed of the reflecting strip and the reflecting plate, the signal receiving and transmitting direction of the antenna is accurate, and the antenna is more compact. And the antenna telescopic rod can be stretched and extended, the reflection strip is separated from the reflection plate in the extension process, the radiation area for signal sending and receiving is increased, the height is increased after the whole structure is completely unfolded, the height and the receiving area of the antenna can be adjusted without assistance of external equipment.

The application discloses a large-diameter rib-column tension type deployable antenna mechanism and relates to a deployable antenna, which is used for solving the problems of the current lack of large-scale deployment mechanism of the existing tension type antenna mechanism and the large mass and low rigidity of the large-diameter antenna deployment structure. The application comprises a telescopic column, a plurality of rib units and a motor screw rod control unit. The motor screw rod control unit is installed in the middle of the telescopic column. The plurality of rib units are arranged in the circumferential direction. The root of each rib unit is connected with the motor screw rod control unit. The application adopts the bifurcation design of the rib end, reduces the length of the outermost circle of the tension cable, reduces the rope suspension depth, can obtain the effective diameter of the large antenna with less rib number, and makes the structure mass lighter due to the less rib number. The three-circle cross tension cable between the adjacent ribs, the telescopic column in the center and the tension cable at the rib end are designed, so that the structure is tensioned into a whole, and the rigidity of the structure is improved. The application belongs to the technical field of aerospace engineering.

The invention relates to the technical field of communication equipment, in particular to a communication base station which comprises a baseband processing unit, a radio frequency processing unit and an antenna feeder system which are installed on a stand column, the antenna feeder system is movably installed on the side portion of the stand column through a stretching component, and a movable frame of a stretching component body is installed on the side portion of the stand column in a sliding mode; the working angle and position of the antenna feeder system are adjusted by controlling the extension amplitude of the antenna feeder system on the side part of the stand column, so that the capability of resisting severe weather of the antenna equipment is improved; under the condition of hail weather, the antenna feeder system is erected, and the hail impact area is reduced; under the condition of storm weather, the antenna feeder system is folded towards the position close to the stand column, the extending distance of the antenna feeder system is shortened, the pressure borne by the connecting component is reduced, and the connecting component is prevented from being broken and damaged.

The embodiment of the invention provides an antenna. The antenna comprises a telescopic assembly, a reflection assembly and an electromechanical conversion assembly, the telescopic assembly comprises a fixed end and a free end, and the fixed end of the telescopic assembly is connected with the first end of the electromechanical conversion assembly; the length of the telescopic assembly is adjusted by stretching or compressing the free end of the telescopic assembly. The mechanical stress state of the first end of the electromechanical conversion assembly is adjusted by adjusting the length of the telescopic assembly, so that the mechanical vibration characteristic of the electromechanical conversion assembly is adjusted. The reflection assembly is connected with the second end of the electromechanical conversion assembly, and the reflection assembly adjusts the electromagnetic field distribution of the antenna by reflecting the electromagnetic radiation converted by the electromechanical conversion assembly; the first end of the electromechanical conversion assembly and the second end of the electromechanical conversion assembly are opposite ends. The antenna can improve the radiation efficiency.

The utility model relates to the technical field of watches, in particular to a telescopic antenna cavity structure of an intelligent watch, which comprises a watch body, the top surface of the watch body is coaxially and rotatably connected with a rotary cover, the inside of the watch body is movably connected with a liftable lifting seat, and the top of the lifting seat is provided with a ceramic antenna module. The surface of the rotary cover is cooperatively provided with a probe hole for the ceramic antenna module to extend out, the surface of the lifting seat is fixedly connected with a guide block, a spring is fixedly connected between the guide block and the meter body, the bottom surface of the rotary cover is cooperatively provided with an arc-shaped inclined wall for limiting the guide block, and the highest point of the arc-shaped inclined wall is communicated with the probe hole. According to the technical scheme of the utility model, the problem that the static structure is difficult to adapt to the requirements of dynamic scenes in the antenna design of a conventional watch with a metal watchcase can be solved.

The application discloses a beam reconfigurable horn antenna device and a use method thereof, and belongs to the technical field of antennas, and comprises: a wave module which is fixedly arranged at the tail end of the horn antenna device; a three-axis telescopic framework which is connected to the front end of the wave module, and is composed of at least a transverse electric control telescopic component, a longitudinal electric control telescopic component and a depth direction electric control telescopic component, and is used for changing the aperture and the longitudinal depth size of the horn antenna; a distance feedback device which is arranged at the aperture position of the three-axis telescopic framework, and is used for detecting the actual aperture size in real time and feeding back the actual aperture size to a control extension; and a control extension which is electrically connected with the transverse electric control telescopic component, the longitudinal electric control telescopic component, the depth direction electric control telescopic component and the distance feedback device. The beam reconfigurable horn antenna device has the advantages of simple structure, small size, high structural strength, and can expand horn antennas of various frequency bands and gains, and has high development and use potential.

The application discloses a spotlight antenna mounting device and relates to the technical field of spotlight antenna mounting. The spotlight antenna mounting device comprises a fixed support assembly and a spotlight antenna connecting assembly. The fixed support assembly comprises at least two mounting surfaces, and any two mounting surfaces intersect with each other. The spotlight antenna connecting assembly is detachably connected with any one of the at least two mounting surfaces. The spotlight antenna connecting assembly of the spotlight antenna mounting device provided by the application has multiple connection postures which can be selected, so that the spotlight antenna mounting device can be flexibly adapted to the installation requirements of the spotlight antenna in various complex installation environments, such as a parapet wall, a roof slope or a pointed tile.

The fine-tuning type high-efficiency antenna and the prevention method can prevent the bad weather floating object from hitting, and belongs to the technical field of fine-tuning type antenna. In order to solve the problem that the antenna in the bad environment is easily hit by the gravel rolled up by the wind force, the normal operation of the antenna is affected, and even the signal transmission operation of the antenna is directly interrupted. If a protective device is directly added around the antenna, the signal receiving performance of the antenna is easily affected. The cover plate is swung to the upper end of the fine-tuning type antenna part to form a shielding cover, and is in an inclined state. At this time, the fan is towards the upper end of the fine-tuning type antenna part, and the wind force is applied to the fine-tuning type antenna part from top to bottom. The shielding cover shields the fine-tuning type antenna part in the bad weather. The rotation axis points of the traction swing rod and the cover plate are perpendicular to each other, so as to expand the activity range of the cover plate and the traction swing rod. Under the mutual auxiliary cooperation, the flying birds are driven away regularly, and the functionality of the cover plate is improved.

This invention discloses a large-aperture radio telescope system for the far side of the moon, comprising: an antenna interferometer array, an electro-optic conversion link, a lunar digital center, a relay transmitting antenna, a lunar relay satellite, and a ground data processing center. The antenna interferometer array acquires scene radiation signals using the principle of integrated aperture interferometry and transmits these signals to the electro-optic conversion link. The electro-optic conversion link receives the scene radiation signals, performs electro-optic modulation to convert them into optical signals, and transmits them to the lunar digital center. The lunar digital center demodulates the signals and transmits the modulated signals to the lunar relay satellite via the relay transmitting antenna. After up-conversion and forwarding, the signals are sent back to the ground data processing center for large-scale data processing and inversion imaging. This invention lays an important foundation for the engineering realization of a lunar-based large-aperture radio telescope.

The application provides a protection device for wired communication equipment, which comprises a base, wherein a swing mechanism, a lifting mechanism, an extending mechanism, a cleaning mechanism, a detecting mechanism and a balancing mechanism are arranged in the base; the protection device has the functions of communication signal enhancement, lightning protection, rainwater power generation, antenna cleaning, balance state detection and equipment balance maintenance; the communication capacity of the communication equipment is increased through the front-back swing of the second antenna; the lightning protection effect is improved through the up-down movement of the first antenna and the first lightning rod driven by the half circular gear and the continuous swing of the four second lightning rods driven by the cam; the rainwater is collected and the power generation shaft is driven to rotate by the rainwater impact rotating plate, the power generation shaft drives the generator to generate electricity, the stored rainwater is used for water spraying cleaning and water cooling of the antenna, and the balance state of the equipment is detected by the ball and the equipment is automatically balanced by the gravity ball.

The invention discloses a modular assembled satellite antenna, and belongs to the technical field of satellite antennae, the modular assembled satellite antenna comprises a main body, an assembled antenna is carried at the top end of the main body, the main body comprises a main frame, an auxiliary storage box is fixed on the back surface of the main frame, and a sealing cover is coupled and clamped on one side of the outer wall of the auxiliary storage box. A telescopic handle is fixed to the top end of the auxiliary storage box, a pulley block is fixed to the bottom end of the auxiliary storage box, and a lifting table is carried at the top end of the main frame. According to the assembled satellite antenna, the assembled antenna, the steering engine and the control box are integrated, the overall size is reduced, the assembled antenna is combined in an assembled mode, meanwhile, the assembled antenna can be matched with an electric screw rod structure to drive a lifting table in threaded connection to descend, and the assembled antenna can be directly stored in a storage groove when moved and stored; and each group of antenna panels can be stored in the auxiliary storage box, so that the antenna panels can be conveniently carried by matching with a pulley block and a telescopic handle at the bottom, the overall structure is more convenient and stable, and the antenna panels can be placed and used at any time.

The invention belongs to the technical field of digital communication, and particularly relates to an airborne multi-mode fusion digital air emergency communication command device which comprises an unmanned aerial vehicle body, a base and a satellite antenna which are sequentially stacked and installed into a whole. The bottom of the unmanned aerial vehicle body is provided with lifting supporting legs used for rising and falling supporting and a cable used for conducting electric energy and data transmission with ground equipment. The cable is formed by stacking a magnetic rubber layer, an insulating layer and a wire group layer, an elastic metal wire penetrates through the insulating layer, the insulating layer is attached to one end of the bottom of the base to be bent into a spiral shape, and the elastic metal wire is spirally attached through magnetic attraction force of the magnetic rubber layer; a linkage rod used for regulating and controlling the signal receiving angle of the satellite antenna is arranged between the foot root of the lifting supporting leg and the bottom of the satellite antenna. The satellite antenna with the specific diameter can be carried through the mooring unmanned aerial vehicle, the satellite antenna can be stably suspended in the air, meanwhile, the signal receiving angle can be adjusted according to needs in the using process, the influence of severe weather is small, and the satellite antenna can more stably work in the air.

The utility model discloses a geological radar antenna support for tunnel detection, which comprises a mounting table, the mounting table is fixed at the top of an extension frame, the extension frame is inserted into a lifting frame, the lifting frame is inserted into a rotating frame, the rotating frame is rotatably connected with a top frame through trunnions on two sides, the top frame is provided with four supporting legs, the supporting legs are of telescopic structures and are arranged on a base, and the base is provided with a base. And universal wheels are arranged below the base. The geological radar antenna can be conveniently driven to lift and incline, geological detection work can be conveniently carried out on the top and the side wall in a tunnel, the structure is simple, operation is stable and safe, operation is convenient and fast, the device can be suitable for geological detection work of tunnels of different types and different sizes, and the application range is wide. The device not only improves the convenience of the detection work, but also reduces the risk of accidents caused by manual operation, improves the safety of the detection work, saves time, labor and cost, and is safe and reliable.

The invention discloses a relay antenna structure and a vehicle-mounted rotor unmanned aerial vehicle, relates to the technical field of unmanned aerial vehicle antennas, and mainly solves the problem that manual intervention operation is needed when the length of a VHF frequency band antenna of a vehicle-mounted unmanned aerial vehicle is between 800mm and 1300mm. When the antenna automatically stretches out and draws back, extra power does not need to be provided, the antenna does not need to be manually operated to be unfolded and folded, the automation degree of the vehicle-mounted unmanned aerial vehicle when the communication relay function is achieved is improved, the operation time is obviously shortened, personnel do not need to climb for operation, and the safety of the personnel is greatly guaranteed.

The invention discloses a telescopic antenna hydraulic energy filter, which belongs to the technical field of hydraulic systems and comprises a positioning ring, a first energy filtering unit and a second energy filtering unit, the first energy filtering unit and the second energy filtering unit are of variable-diameter annular structures extending outwards along the positioning ring, the diameters of the ends, connected with the positioning ring, of the first energy filtering unit and the second energy filtering unit are the largest, and the diameters of the first energy filtering unit and the second energy filtering unit are gradually reduced from the ends connected with the positioning ring to the ends away from the positioning ring. Therefore, an opening and closing structure is formed; and the first energy filtering unit and the second energy filtering unit are provided with a plurality of energy filtering blades which are circumferentially arranged at intervals. The invention further discloses a hydraulic pipeline joint with the energy filter and an installation method. According to the invention, through a'closing-in-opening 'two-stage variable cross-section flow channel structure, the local impedance characteristic of an oil way is changed, and the problem of structural resonance noise which is easily generated in a hydraulic pipeline system and is excited by fluid pulsation is solved.

The application discloses a folding and unfolding mechanism of a four-surface array antenna, which comprises a mounting platform, a lifting mechanism arranged on the mounting platform, the lifting mechanism comprising a lifting upper frame, a lifting driving element, a swing rod I and a swing rod II, the lifting driving element being arranged between the lifting upper frame and the mounting platform, a front array surface and a rear array surface being hingedly connected to the front and rear ends of the lifting upper frame, the front array surface and the rear array surface being hingedly connected to the swing rod I between the mounting platform, left and right unfolding mechanisms being arranged on the lifting upper frame, a left array surface and a right array surface being hingedly connected to the left and right ends of the left and right unfolding mechanisms, the left array surface and the right array surface being hingedly connected to the swing rod II between the mounting platform. The application has the advantages that a folding and unfolding mode of a vehicle-mounted large-caliber four-surface array antenna from a transportation state to a working state is provided, single-vehicle transportation of the large-caliber four-surface array antenna can be realized and the transportation limit requirements of roads and railways can be met, the four-surface array antenna can be automatically and quickly unfolded, precious battlefield time is saved, and the battlefield survival capability is improved.

The utility model relates to a universal rod-shaped antenna, which comprises a mounting seat, a movable seat horizontally and rotatably arranged at the upper end of the mounting seat, a telescopic rod-shaped antenna longitudinally hinged at the upper end of the movable seat, and a spiral antenna arranged at the tail end of the telescopic rod-shaped antenna, a protective outer cover is arranged at the tail end of the telescopic rod-shaped antenna, and the helical antenna is arranged in the protective outer cover; a first wiring channel is axially arranged in the telescopic rod-shaped antenna, a second wiring channel is longitudinally arranged on the movable seat corresponding to the first wiring channel in a penetrating manner, a longitudinal third wiring channel is arranged on the mounting seat corresponding to the second wiring channel, and a wiring groove communicated with the lower end of the third wiring channel is formed in the outer side wall of the lower end of the mounting seat; the device is small and exquisite in overall structure, capable of extending or shortening, adjustable in orientation, high in adaptability and stable in signal.

This invention relates to the field of wireless communication technology and discloses a retractable reflector-assisted 5G antenna structure, including a mounting bracket, a protective box mounted on the mounting bracket, and a dynamic RIS (Radio Reflector System) body slidably mounted on the upper end of the protective box via a sliding hole. The dynamic RIS body consists of a reflective panel and a back plate. A support slide is slidably mounted inside the protective box. A telescopic support portion is shared on both the protective box and the support slide, and a snap-fit ​​portion is shared on both the dynamic RIS body and the support slide. This retractable reflector-assisted 5G antenna structure effectively solves the problems in existing technologies, such as the need to improve the installation stability of the mounting bracket, the limitations of the application of dynamic RIS in complex environments, and the need for protective measures to prevent performance degradation or equipment damage after severe weather warnings are issued, sometimes requiring temporary equipment recall or shutdown, frequent equipment inspection and maintenance, and increased long-term maintenance costs.

The invention belongs to the technical field of communication towers, and particularly relates to a polyurethane composite material mobile communication tower which comprises a mobile unit, a radiation unit, a reflecting plate, a power distribution network and an antenna housing. The lifting frame is arranged at the telescopic end of an electric push rod arranged on the back surface of the antenna housing; when the lifting frame ascends and descends, the driving piece is started to drive the rotating blocks to rotate, and the adjacent rotating blocks are hinged end to end, so that the rotating blocks can rotate in an arc-shaped state, the rotating blocks are helped to drive the cleaning cotton to be better attached to the receiving and transmitting surface of the antenna housing, and the cleaning effect is improved; the cleaning strength of the cleaning cotton driven by each rotating block to make contact with the surface of the radome is the same, and the situation that due to the fact that the cleaning strength of the surface of the radome is different, the surface of the radome is not uniform in wiping strength, abrasion is generated, and a coating on the surface of the radome is damaged is avoided.

An underground enclosure for housing electrical components is provided. The underground enclosure may include a shell defining an interior compartment housing a lift system, an equipment rack structure connected to the lift system, a top panel with a compartment opening for accessing the interior compartment, and an enclosure cover adapted to cover and removably seal the compartment opening. In certain applications, a telecommunications base station may also be provided. The telecommunications base station may include the underground enclosure and a cellular base station, the cellular base station including an antenna and a power source coupled to a signal processing unit. In alternative embodiments, the underground enclosure may be configured as a cube-shaped structure or a tubular structure.

A millimeter wave duplexer and dual-polarized antenna feed source integrated system comprises a shell, the shell is arranged on a rod body through an adjusting mechanism, the adjusting mechanism comprises an installation ring frame arranged on the rod body in a sleeving mode and a plurality of ratchet bars arranged on the surface of the rod body, and the outer side of the installation ring frame is provided with an accommodating cover extending in the axial direction of the installation ring frame. A pawl, a torsional spring and a driving assembly used for driving the pawl to rotate are arranged in the containing cover, the pawl is rotationally arranged in the containing cover through a rotating shaft, the rotating shaft is coaxially sleeved with the torsional spring, one end of the torsional spring is connected with the inner wall of the containing cover, the other end of the torsional spring is connected with the pawl, and the driving assembly drives the pawl to rotate in the first direction. In the process that the clamping end of the pawl is meshed with the ratchets of the ratchet bar, the mounting ring frame moves in the length direction of the ratchet bar so as to change the height of the mounting ring frame, unlocking and resetting of the pawl can be completed only through the driving assembly, and the adjusting efficiency is improved.