40 results about "Lateral displacement" patented technology

The invention relates to the technical field of constructional engineering equipment, in particular to a rigidity and energy dissipation adjustable composite energy dissipation bearing device which comprises a first connecting plate, a second connecting plate, a first damping part and a second damping part. The first damping piece is arranged on the first connecting plate on the column body in a friction sliding mode, and the second damping piece is connected between the beam body and the first damping piece in an included angle mode, so that the flexural rigidity of the beam-column joint can be effectively improved under the action of frequent earthquakes, and the initial rigidity and lateral displacement resistance of the structure are enhanced; the rigid response performance of the structure under the action of small earthquakes is improved; the second damping piece can adjust the energy dissipation path through the change of the included angle between the length direction of the second damping piece and the axis of the column body in the earthquake action process, the friction sliding mechanism of the first damping piece is matched, the energy dissipation capacity of the joint under the earthquake action is effectively improved, and therefore structural stress concentration is reduced, and structural damage is delayed. The structure is light in weight, convenient to install and wide in application range.

The invention discloses an optimization method of a low-loss bending waveguide, which comprises the following steps: firstly, adopting NA bending as a basic bending path, determining two optimal boundary NA curves for a given equivalent bending radius Reff, and forming a width gradually-changed NA bending waveguide structure; lateral shift amounts din and dout are introduced into the input end and the output end of the constructed NA bending waveguide structure with the gradually-changed width respectively, and optimal lateral shift amounts din and dout are obtained through step-by-step parameter scanning and simulation optimization; and based on the optimal lateral shift amounts din and dout, obtaining a curved waveguide structure combining an NA curved path, width gradient and a specific lateral shift parameter. According to the method, the mode mismatch loss and the radiation loss can be remarkably reduced at the same time for the NA bending waveguide with the ultra-small radius, and the total transmission loss of the bending waveguide is further reduced on the basis of the prior art.

The invention relates to the technical field of steel structure engineering construction, in particular to a super-long independent steel column segmented locking type temporary stabilizing device and a construction method thereof, and is suitable for the overall lifting stage of a multi-layer aerial corridor. The device comprises a first locking assembly surrounding a concrete column and providing an X-direction lateral fulcrum; the second locking assembly is fixedly connected to the surface of the steel column to form a force transmission interface; and the connecting conversion assembly connects the steel column and the concrete column into a whole, so that the X-direction load of the steel column is transmitted to the concrete column in sections. The super-long steel columns are temporarily decomposed into short column stress sections with the length not larger than the designed length, and lateral displacement is remarkably restrained. The construction method comprises the steps that the device is installed at the corridor joint, pre-tightening force is synchronously applied, displacement is monitored in real time, overall dismantling is conducted after lifting is completed, and no residue exists after dismantling. The method is not pre-buried and fully recycled, super-long columns are restored to be in a short column stress state, lateral displacement is reduced, steel is saved, the construction period is shortened, green construction and appearance completeness are both considered, and the method is suitable for a large-span corridor overall lifting project.

The invention discloses a design method of a hinge type curved pipe pressure balance type expansion joint based on CAESAR II, and relates to the technical field of simulation of expansion joints in CAESAR II. The method comprises the steps that an expansion joint body pipe section of the hinge type curved pipe pressure balance type expansion joint is established in a CAESAR II according to initial design parameters, a hinge model comprising multiple sections of hinge plates connected in sequence is established in the radial direction of the expansion joint body pipe section, and a pin shaft is simulated by applying a first constraint to the connecting position of every two adjacent hinge plates, establishing a simulation model of the hinge type curved pipe pressure balance type expansion joint; performing displacement analysis on the simulation model to obtain an axial displacement value and a transverse displacement value; and updating the simulation model based on the process design parameters, and carrying out iteration. The technical problems that according to a traditional method, only a whole rigid body structure can be adopted for simple simulation, the real mechanical behavior of the expansion joint cannot be reflected, the displacement response of the expansion joint is seriously shifted from the actual physical state, and design of materials, structural parameters and the like of the expansion joint is not accurate are solved.

The invention provides a bow and arrow side pad with position and speed measurement, which comprises a protective shell in a hollow column shape and used for being detachably mounted on a bow handle through threads, and a measuring assembly detachably accommodated in the protective shell and used for measuring the position and speed of an arrow, comprising a measuring shell, a control panel, a light wave emitting sensor, a light wave receiving sensor and a wireless transmission module, the wireless transmission module is used for wirelessly transmitting measured data to external electronic equipment, and an adjusting assembly is arranged in the protective shell; wherein the measuring shell is in sliding fit with the protective shell, so that the measuring assembly can generate lateral displacement under the action of the adjusting assembly. According to the invention, the core function of applying accurate lateral force to the arrow through the adjusting assembly is reserved, and automatic acquisition and wireless transmission of the to-be-launched position and the departure initial speed of the arrow are synchronously completed through a built-in light wave sensing and wireless transmission system on the premise that the normal operation process of a shooter is not interfered at all.

This invention relates to the field of pile foundation testing, and more particularly to a pile foundation testing device and method for civil engineering construction. The device includes a tamping apparatus for testing the pile body and testing components. In this invention, when the pile body tilts, the light spot undergoes vertical and / or lateral displacement on the receiving plane. If the tilt causes the light spot to move upward or downward, it may partially or completely enter the light aperture range of adjacent adjustment apertures. For example, when the top of the pile tilts to the right, due to the clockwise rotation of the transmitting end, the projection point of the 45° beam moves upward on the receiving end plane. The light spot originally illuminating the middle adjustment aperture may simultaneously cover the edge of the light aperture of one or two upper adjustment apertures. If the tilt angle is large, the center of the light spot may completely move out of the original aperture and into the adjacent aperture area, or even cross multiple apertures. Therefore, the tilt amount of the pile body can be determined by monitoring the number of infrared receivers that have sensed infrared radiation.

The invention relates to the field, in particular to pile foundation detection equipment for civil engineering construction and a detection method, the pile foundation detection equipment comprises a tamping device used for detecting a foundation pile body and a detection assembly, and in the pile foundation detection equipment, when the foundation pile body inclines, light spots generate vertical and / or transverse displacement on a receiving plane. If the light spot moves upwards or downwards due to inclination, part or all of the light spot possibly enters the range of the light through hole of the adjacent adjusting aperture. For example, when the top of a foundation pile inclines rightwards, the whole transmitting end rotates clockwise, the projection point of a 45-degree light beam moves upwards on the plane of the receiving end, and light spots originally irradiated on the middle adjusting aperture may cover the edges of light through holes of one or two adjusting apertures above at the same time; if the inclination angle is large, the center of the light spot may completely move out of the original through hole, enter an adjacent through hole area and even cross a plurality of through holes, and therefore the inclination amount of the foundation pile body can be judged according to the number, monitored by the terminal, of the infrared receiving ends which sense infrared rays.

The invention provides a polarization-insensitive tunable light beam deflector based on cascade metasurfaces, and relates to the technical field of optics. The polarization-insensitive tunable light beam deflector sequentially comprises a first-layer metasurface, an air gap and a second-layer metasurface from bottom to top, the first-layer metasurface and the second-layer metasurface are both composed of elliptical nano-column arrays which are periodically arranged; the lateral displacement dx of the second layer of metasurface relative to the first layer of metasurface in the x direction and the lateral displacement dy of the second layer of metasurface in the y direction are adjusted in a mechanical mode, the total phase distribution of the cascade metasurface is changed to generate a phase gradient, and continuous deflection scanning of an emergent light beam in a two-dimensional space is achieved. The polarization-insensitive metasurface unit structure is realized by adopting the elliptical nano-columns. The nanorods are rotated by 45 degrees, so that the unit structures have the same regulation and control capability under x and y polarization, and the problem that a traditional anisotropic structure is sensitive to the polarization state of incident light is solved.

This invention provides a dual-platform absorbing tip transverse positioning system, installed on the floor of an anechoic chamber to simulate different radio wave environments. The system consists of two parallel hydraulic platforms with densely arranged absorbing tips on them, and a raised floor is mounted on the hydraulic platforms. The hydraulic platforms are driven by hydraulic cylinders to lift and lower scissor supports. Sprockets are located at both ends of the platforms, driven by chains, and a transverse motor is also provided. The motor drives the sprockets through gear engagement, causing the absorbing tips on the platforms to move laterally. The raised floor, originally a metal reference surface, can be adjusted to a non-reflective environment according to testing requirements. The hydraulic platforms rise, driven by the transverse motor, and the absorbing tips of the two platforms unfold laterally, providing a non-reflective test. The aforementioned actions are reversed, causing the platforms filled with absorbing tips to retract and disappear under the raised floor. This system can flexibly switch between different testing environment conditions to meet the diverse needs of the anechoic chamber.

This invention discloses a method for measuring the diffraction efficiency of a grating based on a partitioned grating reflector, comprising: a laser source, a collimating mirror, a plane mirror, a partitioned grating reflector, a beam splitter cube, an electric turntable, a lateral displacement stage, a screen, a first photodetector, and a second photodetector. The electric turntable supports the plane mirror and the partitioned grating reflector; the lateral displacement stage supports the laser source, the beam splitter cube, the screen, the first photodetector, and the second photodetector. First, the plane mirror is used to perform a coarse vertical calibration of the laser incident direction. Then, the partitioned grating reflector is installed, and a fine calibration is achieved through the reflection zone, calibrating the position of the reflected light spot. Based on this, the laser source is moved so that the incident light illuminates the grating under test, aligning the position of the zero-order diffraction spot with the calibrated reflected light spot position, thus achieving effective alignment. Consistency verification of the measurement process is achieved through multiple comparisons of the calibration results.

The present disclosure relates to a system for determining corrugation of a film, which has a predetermined dimension in a width direction and extends in a longitudinal direction, due to tension acting on the film and inhomogeneity of a film material in a roll-to-roll inline apparatus that conveys the film in the longitudinal direction. The system includes: a lateral displacement sensor mounted on one or more of two sides of the film in a width direction to be spaced apart from a surface of the film, and configured to measure a displacement of the surface of the film; and a ripple determination unit for converting a lateral displacement value of the film surface as a function of time measured by the lateral displacement sensor into an amplitude value as a function of the frequency signal and comparing the converted amplitude value with a preset amplitude value as a function of the frequency signal, to determine the presence or absence of corrugations in the membrane.

An interferometer based on an atomic force microscope ("AFM") uses a light source and a beamsplitting optical interface to split a light beam into a signal beam and a reference beam. Both the signal beam and the reference beam are focused near an AFM cantilever. A beam displacer introduces a lateral displacement between the signal beam and the reference beam that causes the center of the signal beam to be separated from the center of the reference beam by more than half the sum of their beam diameters in at least one plane between the beam displacer and a focusing lens structure. A detector operates to determine a difference in the optical path length between the signal beam and the reference beam to determine information about movement of the cantilever.

A lens for vehicular lamp which projects a light distribution image including a non-irradiation area which does not irradiate a mask object and an irradiation area which irradiates other areas, wherein the lens for vehicular lamp is configured to clearly project a first non-irradiation area for masking at least a mask object that exists at a long distance in a vicinity of an intersection of a horizontal line and a vertical line in the light distribution image onto a first location that is a first distance away in an optical axis direction of the lens for vehicular lamp, and a second non-irradiation area for masking at least a mask object that exists at a close distance laterally displaced from an intersection of the horizontal line and the vertical line in the light distribution image onto a second location.

The application discloses a target point accurate positioning and large workpiece measuring device and a measuring method thereof. The motion range adjusting part is used for adjusting the position of the measuring point in a large range, controlling the movement of the measuring device, and making the measuring device reach a general direction suitable for the operation of the camera group; the angle adjusting part is used for adjusting the working visual angle of the device in 360 degrees; the vertical displacement adjusting part is used for calibrating target points of different heights; and the horizontal displacement adjusting part is used for controlling the movement range of the camera group, so as to improve the measuring precision. The application solves the problems of difficult initial calibration and low precision in the prior art.

The utility model relates to light control biaxial horizontal material collecting machine technical field, and disclose a light control biaxial horizontal material collecting machine with tension adjusting mechanism, including the bottom plate, the bottom plate top fixedly connected with light control biaxial horizontal material collecting machine body, the light control biaxial horizontal material collecting machine body top both sides are all fixedly connected with the transverse board, the transverse board top one side fixedly connected with the workstation, the workstation bottom both sides are respectively fixedly connected with first shell and second shell. The utility model discloses the setting of transmission motor can drive first threaded rod and second threaded rod synchronous rotation to drive threaded bushing and mobile plate horizontal displacement to adjust the position of the tensioning roller, realize the dynamic adjustment to the coiled material tension, and this is according to the characteristics of different materials and process requirement flexible adjustment tightness, avoid the material relaxation, wrinkle or overstretching in the process of winding due to tension uneven, reduce material loss and the rate of defective products.

The invention belongs to the technical field of ultra-precise angle measurement, and discloses a six-dimensional angle measurement device and method based on wavefront interference fringes. Three paths of detection laser are used for generating three wavefront interference light spots, spatial frequencies and phases of the light spots in the horizontal direction and the vertical direction are calculated respectively, and simultaneous decoupling is carried out to accurately measure six-degree-of-freedom information of axial displacement, longitudinal displacement, lateral displacement, pitching, deflection and rolling angles of the reflector. According to the six-degree-of-freedom measuring device, single-principle integrated six-degree-of-freedom geometric quantity measurement can be achieved, the measurement resolution is high, the measurement result can be directly traced to the laser wavelength, and the requirement of high-end equipment for ultra-precise six-degree-of-freedom geometric quantity measurement is met.

The utility model discloses a gantry lifting mechanism for an immersion type electrophoresis pool, which relates to the technical field of electrophoresis production lines and comprises a connecting plate, a positioning plate and a lifting seat, and a dismounting positioning mechanism is arranged at the joint of the positioning plate and the lifting seat and used for quickly dismounting the positioning plate and the lifting seat. According to the gantry lifting mechanism for the immersion type electrophoresis pool, through the clamping design of the I-shaped butt joint blocks and the butt joint grooves, a stable embedding relation is formed, transverse displacement in the lifting process is effectively avoided, the stability of the overall structure is guaranteed, the stability of the whole structure is improved, and the service life of the gantry lifting mechanism is prolonged. In cooperation with a first screw with reverse threads and a limiting rod structure in the disassembly and assembly positioning mechanism, synchronous opening and closing of a clamping plate can be achieved by rotating the screw, disassembly and assembly of a positioning plate and a lifting base are rapidly completed, operation is convenient and efficient, the convenience of adaptive replacement of the clamping unit is greatly reduced, and the production flexibility and efficiency are improved.

The application discloses a physical-based Fourier ptychographic light source pose correction method. The low-resolution image obtained through the Fourier ptychographic light path is affected by the pose deviation of the LED lamp plate in the system, thereby affecting the reconstruction quality. The application firstly constructs a physical model of the bright field to dark field boundary of the captured image for the microscope used, collects a group of low-resolution images of empty slides, screens out transition images with bright-dark boundaries, and calculates the bright-dark field boundary information of the transition images and the unbiased transition images generated by the model to solve the full pose parameters (including the distance from the sample, two orthogonal lateral displacements, the in-plane rotation angle and two tilt angles) of the misaligned LED array. The illumination angle can be accurately corrected, thereby ensuring the accuracy and uniformity of the illumination effect. It is verified through experiments that the application achieves good correction effect in practical application and enhances the robustness of the Fourier ptychographic reconstruction system to the light source position deviation.

This invention provides a non-contact online visual measurement method and system for wheel-rail dynamic attitude parameters, belonging to the field of 3D point cloud visual measurement technology. Based on the principle of stereo vision measurement, it reconstructs a wheel-rail cross-sectional profile point cloud sequence from the acquired image sequence of the structured light-illuminated cross-sectional area on the outer side of the wheel and rail, according to calibration parameters. Based on the reconstructed wheel-rail cross-sectional profile point cloud sequence, it partitions and fits planes, calculates and decomposes the angles of the normal vectors of specific planes using multi-frame information, and obtains angle parameters. Based on the reconstructed wheel-rail cross-sectional profile point cloud sequence, it fits the wheel circle using inter-frame and geometric constraints to determine key points in the wheel-rail region and the rail reference plane, and calculates wheel-rail displacement parameters. This invention enables simple, accurate, and safe non-contact measurement of lateral displacement, heave, yaw angle, and roll angle of the wheel during train operation; it provides rapid, accurate, and reliable theoretical and technical support for non-contact measurement of wheel-rail motion attitude.

The invention discloses a backboard design method for maintaining the shape of an optical reflection mirror surface in a wide temperature change environment, and belongs to the technical field of precision optics. The method comprises the following steps: acquiring a curvilinear equation and a material thermal expansion coefficient of a to-be-processed reflecting mirror surface; selecting a plurality of sampling points based on the mirror curve equation, and calculating transverse displacement of the sampling points due to thermal deformation of the substrate material in a temperature change environment; calculating the longitudinal compensation displacement required by the sampling point according to the shape maintaining requirement; and based on the relation among the longitudinal compensation displacement, the thermal expansion coefficient and the temperature change, the backboard thickness at the corresponding sampling point is solved, a backboard curvilinear equation is obtained through fitting, and forming machining is conducted based on the backboard curvilinear equation. According to the invention, the nonlinear relation between the reflecting mirror surface and the curved surface of the back plate is established, and the axial-longitudinal thermal deformation coupling of the back plate and the mirror body is utilized to actively counteract the thermal defocus of the mirror surface, so that passive thermal compensation is realized, the problem of curvature drift of the optical reflecting mirror surface in a wide temperature change environment is effectively solved, and the device has the advantages of simple structure, high reliability and low cost.

The utility model discloses a convenient installation structure and light hydrocarbon gas detection device, and convenient installation structure includes: installation base body, connecting structure and elastic locking structure, installation base body is configured in connecting medium container, and is provided with at least one connecting groove, connecting structure includes connecting piece and at least one insert, the connecting piece is used for connecting detection element, at least one the insert is connected with connecting piece, and with connecting groove opposite setting, can insert in connecting groove and pass through rotation or transverse displacement and realize the locking connection, elastic locking structure is connected with connecting piece, can be compressed when insert and connecting groove locking connection, to produce the reverse force of preventing insert and take out, and the device has realized light hydrocarbon gas detection device's quick, simple and easy and firmly install, has improved installation efficiency, has reduced installation cost.

This invention belongs to the field of laser technology, specifically relating to a spatial four-parameter precision measurement system and method for beam lateral displacement and deflection. To improve measurement accuracy and anti-interference capability, the invention sequentially arranges an electro-optic modulator (EOM), a first high-reflection mirror, a second high-reflection mirror, a three-mirror cavity, a plane mirror, a beam splitter detector (SD), and a mixer in the output optical path of the laser. After demodulation, low-pass filtering, and quantization, combined with parameters such as Planck's constant, laser wavelength, and cavity length, and setting the signal-to-noise ratio to 1, the minimum measurable tilt angle can be derived. For the lateral displacement signal, the same detection and demodulation logic is used to extract the corresponding low-frequency error signal and quantize it, deriving the minimum measurable lateral displacement, and finally outputting the quantized error signals corresponding to the two types of mismatches.

The utility model relates to a three-dimensional imaging device based on structured light projection, and belongs to the field of three-dimensional imaging devices. Comprising a photographing mechanism, a projection mechanism, a transverse displacement mechanism, a vertical displacement mechanism, a storage mechanism, a workbench, a supporting stand column and a control mechanism. The object placing mechanism and the supporting stand column are both arranged at the top end of the workbench, an object to be measured is movably arranged on the object placing mechanism, the vertical displacement mechanism is arranged at the top end of the supporting stand column, the transverse displacement mechanism is installed on the vertical displacement mechanism in a sliding mode, and the photographing mechanism and the projection mechanism are arranged side by side and movably arranged on the transverse displacement mechanism. The control mechanism is arranged in the workbench and connected with the photographing mechanism, the projection mechanism, the transverse displacement mechanism, the vertical displacement mechanism and the storage mechanism. According to the utility model, the cooperative work efficiency of the industrial camera and the projector is improved, and the imaging speed and the measurement precision are optimized; the overall structure is simple and convenient to popularize and apply.

The invention discloses a bolt looseness detection device, and belongs to the technical field of mechanical detection. The device comprises a fixing mechanism, a detection seat, a detection head, a connecting rod, a result amplification rod and a result display assembly. The fixing mechanism is clamped on a plate connected with a detected bolt, a detection head is assembled in the detection seat in a sliding mode, and the detection head is hinged to the result amplification rod through a connecting rod. Micro axial displacement generated by loosening of the bolt is converted into transverse displacement of the result amplification rod through the connecting rod, then secondary amplification is carried out through the rack and gear transmission system, and finally an instrument pointer is driven to rotate and readings are displayed. The bottom of the detection head is provided with centering grooves adaptive to bolts of different specifications, and the floating design of the detection head ensures stable contact. A pure mechanical structure is adopted, micron-order displacement is amplified into visual pointer angle change, and the device has the advantages of being high in sensitivity and reliability, free of a power source, easy and convenient to operate, good in environment adaptability and the like, and is suitable for key bolt state monitoring of various engineering sites.

This utility model discloses a camera bracket machining fixture, including a base plate with a machining opening, a positioning block on one side of the base plate, a clamping mechanism on the other side of the machining opening, and a support block disposed between the positioning block and the clamping mechanism. The positioning block has a flat surface and an inclined surface on the side near the machining opening that abut against the camera bracket. The flat surface has a protrusion that mates with the recess of the camera bracket, achieving multi-directional precise positioning. The clamping mechanism drives the clamping block to press the workpiece against the positioning block, ensuring uniform distribution of clamping force. The support block has a support step and adjustable positioning bolts to support the workpiece and limit lateral displacement. The base plate has a machining opening for easy observation and chip removal during machining, and a rotatable seat is mounted on the side, with a support plate enhancing structural stability. This fixture, through the synergistic effect of a composite positioning structure and a multi-directional clamping device, solves the positioning problem during the machining of irregularly shaped workpieces, and has advantages such as high positioning accuracy, stable clamping, and convenient operation.

This application discloses a coordinate measurement compensation method, device, medium, and equipment for a solid corner reflector, relating to the field of large-size precision engineering measurement technology. The method includes: acquiring the coordinates of the measurement optical center of the solid corner reflector using a laser tracker; calculating the three-dimensional attitude parameters of the solid corner reflector based on the measurement optical center coordinates and calibration parameters, including the coordinate system rotation transformation matrix and the physical depth from the incident surface of the solid corner reflector to its vertex; calculating the refractive geometric parameters of the laser incident on the solid corner reflector based on the three-dimensional attitude parameters and the direction of the incident laser beam; constructing a complete optical path propagation model based on the refractive geometric parameters, and calculating the propagation optical path and lateral displacement of the laser inside the solid corner reflector; and compensating the measurement optical center coordinates of the solid corner reflector based on the propagation optical path and lateral displacement to obtain the compensated physical geometric vertex coordinates. This application can improve the coordinate measurement accuracy of solid corner reflectors.

Phase-contrast images in a charged particle beam system are obtained by guiding a sample-modulated CPB towards a phase plate to displace the diffraction plane relative to the phase plate. Based on the interference fringes in the image, the lateral displacement of the CPB relative to the phase plate can be estimated and adjusted.

The invention belongs to the technical field of ultra-precise angle measurement, and discloses a five-dimensional angle measurement device and method based on wavefront interference fringes. The laser wavelength is used as the traceability reference. The homodyne wavefront interference principle is utilized in a single interference measuring head, two paths of detection laser are used for generating two wavefront interference light spots, the spatial frequencies and phases of respective fringe images in the horizontal direction and the vertical direction are calculated respectively, and simultaneous decoupling is carried out to accurately measure the axial displacement, lateral displacement, pitching, deflection and roll angle deviation of the reflector. According to the five-dimensional geometric quantity measurement device, single-principle integrated five-dimensional geometric quantity measurement can be achieved, the measurement resolution is high, the measurement result can be directly traced to the laser wavelength, and the requirement of high-end equipment for ultra-precise five-dimensional geometric quantity measurement is met.

The utility model relates to a showcase technical field especially is with a kind of special display cabinet of exhibition picture.It includes: cabinet body and the top cover being arranged above the cabinet body, further include: guide wheel and horizontal shift component;The top cover is equipped with the notch being communicated with the inside of cabinet body, the notch both sides are symmetrically equipped with support vertical plate, symmetrically be equipped with combination rod between the two support vertical plate, the combination rod is triangularly arranged, the transmission screw rod being connected with combination rod is equipped in the top cover middle part, guide wheel is all installed on the combination rod;The horizontal shift component is connected with guide wheel, and can drive the guide wheel and carry out lateral displacement along combination rod, the hanging rope that passes guide wheel successively and penetrates into notch is equipped in the horizontal shift component;The utility model is designed to cooperate on structure, can realize the adjustment to the height direction and width direction of hanging point position, is applicable to the hanging demand of different size exhibition picture, need not to destroy, keep the integrity of display cabinet, it is convenient and fast to operate.