100results about How to "Flat contact surface" patented technology

The invention discloses a three-dimensional (3D) printer which comprises a rack, a base, an X-axis movement system, a Y-axis movement system, a Z-axis movement system and a printing device, wherein the rack comprises a left upright post, a right upright post, an upper connecting plate and a lower connecting plate; the upper connecting plate and the lower connecting plate are connected with the left upright post and the right upright post, respectively; the base is connected with the lower connecting plate; the upper connecting plate is connected with a printing supplies connecting rack; the printing supplies connecting rack is connected with a printing supplies fixing disc; the printing device is connected with the X-axis movement system; the X-axis movement system is connected with the Z-axis movement system; the Z-axis movement system is connected with a guide rail of the left upright post and the right upright post; the Y-axis movement system is connected with the base; the X-axis movement system is provided with an X-axis movement guide rail through which the printing device moves; a power supply and a controller which are connected with each other are arranged at the bottom of the base; the controller is connected with the X-axis movement system, the Y-axis movement system, the Z-axis movement system and the printing device. The 3D printer is simple and compact in structure, small in size and low in manufacturing cost.

The invention discloses an FDM (frequency-division multiplexing) 3D (three dimensional) printer. The 3D printer comprises a rack and an X-axis moving system, wherein a controller is connected with the X-axis moving system and a printing device; the X-axis moving system comprises a first numerical control motor and a horizontal X-axis moving guide rail, the horizontal X-axis moving guide rail is connected with a left-side support arm and a right-side support arm, the first numerical control motor is connected with a first synchronous toothed belt, the first synchronous toothed belt is a long-strip belt, one end of the long-strip belt is connected with the left-side support arm, the other end of the long-strip belt is connected with the right-side support arm, a first groove is formed in the left-side support arm, a second groove is formed in the right-side support arm, the left end of the first synchronous toothed belt is meshed and locked with the first groove, the right end of the first synchronous toothed belt is bent inwards, tooth grooves on two sides of a bent part of the first synchronous toothed belt are correspondingly matched with a tooth top to form a gear belt overlap region, and the gear belt overlap region is matched and locked with the second groove. The FDM 3D printer is simple in structure and small in volume and low in cost.

The invention relates to a sand mould of precoated sand for casting single piston ring and a manufacturing method of the sand mould. The sand mould comprises a circular tray body, a pouring system arranged on the circular tray body, a retainer ring and air outlet holes, wherein the pouring system comprises a downsprue, a flow gate, a cross gate and a dead head, the downsprue penetrates through the middle part of the circular tray body, the flow gate arranged on the facade of the circular tray body is communicated with the downsprue through the cross gate, the flow gate is communicated with a ring body groove, the dead head is arranged to be opposite to the flow gate, and the dead head is communicated with the ring body groove through more than two inclined pouring gates; and the retainer ring higher than the surface of the sand mould is arranged on the periphery of the facade of the circular tray body, and more than four air outlet holes passing through the circular tray body are symmetrically arranged on the inner side of the ring body groove between the cross gate and the dead head along the axial line of the cross gate. The piston ring processed by the invention is stable in quality and high in yield, the piston ring casting has the advantages of clear outline, high dimension precision and good surface quality, and the piston ring casting is liable to clean, thereby reducing the processing allowance, reducing the successive processing cost and improving the production efficiency.

The invention provides a simulation test device for a response characteristic of a tunnel lining geological radar and a test method thereof. The simulation test device comprises a main body model made from concrete, wherein a plurality of clamping slots are formed in the main body model; concrete simulation components which are matched with the clamping slots and are used for simulating different lining structure types or different geological defects are arranged in the clamping slots; the concrete simulation components and the main body model are combined to form an integrated model; the geological radar is used for detecting the position above the integrated model to obtain the response characteristics of different lining structures in the geological radar. The simulation test device can be used for simulating the structures of tunnel lining concrete, reinforcement fabrics and steel arches and defects that the untightness of the lining is not matched with disengagement, cracks, caves, ponding and steel bar distribution and the like and can comprehensively simulate various situations in detection of the actual lining quality. The simulation test device can simulate various different situations only by changing the types of the concrete simulation components inserted into the clamping slots and is extremely high in reusability.

The invention relates to the field of medical instruments, in particular to a balloon-type support device for laparoscopic surgery. The support device comprises a hollow rod-shaped support rod, a bottom cover is arranged at the bottom of the support rod, and a top cover is arranged at the top of the support rod. The support rod is provided with a slider, a receiving chamber is formed between the slider and the bottom cover, the receiving chamber is provided with a balloon, and the slider is connected at the top of the balloon. The side wall of the receiving chamber is provided with at least two openings, and the slider is slid toward the bottom of the support rod. The balloon protrudes from the opening to the outside of the support rod. The number of puncture holes is reduced, the connection between the support rod and the abdominal wall is stabilized, the structure is simple, the operation is convenient, and the work difficulty of the medical staff is reduced. Because the contact areabetween the balloon and the inner wall of the abdominal cavity is wider and the contact surface is smoother, on the one hand, the support device has better supporting effect, on the other hand, the pressure injury to the abdominal wall is avoided correspondingly, and the unnecessary trauma caused by surgery of the patient is reduced.

The invention relates to a combined groove-type ironing machine. The combined groove-type ironing machine comprises an ironing groove set. Ironing grooves are in arc shapes with upward arc openings. The ironing groove set comprises at least one rigid groove and at least one flexible groove, and transition grooves with downward arc openings are arranged between the ironing grooves; the first ironing groove of the ironing groove set is a rigid groove, and the second ironing groove of the ironing groove set is a flexible groove; transition-groove installation holes used for being connected with the horizontal edge portions of the transition grooves are formed in the horizontal edge portions of the two ends of the rigid grooves; the transition grooves are fixed onto racks of the rigid grooves and the flexible grooves through installation supports on the two sides. According to the combined groove-type ironing machine, the excellent heat storage performance of the rigid grooves and the ironing effect of the flexible grooves of the ironing machine are combined, cloth grass with a large amount of moisture firstly enters the rigid grooves, and the large amount of moisture is removed; meanwhile, the problem that as supplying of steam is insufficient, the temperature of groove bodies is suddenly lowered, and halting occurs accordingly is solved, and after the damp-dry cloth grass enters the flexible grooves, the good ironing quality can be achieved through the rapid heat exchange capacity, the smooth contact faces and the excellent packaging performance of the thin plate structures of the flexible grooves.

The invention discloses a fluorescent signal detection device of a real-time fluorescent quantitative PCR (Polymerase Chain Reaction) instrument. One end of a screw rod is fixedly connected with a transmission device through a bearing arranged on a guide rail; a slide block is in sliding fit with the guide rail, arranged together with the screw rod and fixedly connected with a second stepping motor; light rays emitted by a light source enter a sample to be detected sequentially through a two-phase color spectroscope, a plane mirror, a lens and a light emitting hole in a light path module shell; a fluorescent group contained in the sample to be detected is stimulated to generate fluorescent light, and the fluorescent light roundly enters the receiving end of a photomuitplier through the light emitting hole, the lens, the plane mirror, the two-phase color spectroscope and a filter lens; an output shaft of the second stepping motor is fixed with the light path module shell; the pulse signal input end and the direction signal input end of a first subdivision driver and a second subdivision driver are connected with the corresponding output end of a controller; the output end of the first subdivision driver is connected with the transmission device; and the output end of the second subdivision driver is connected with the second stepping motor. The fluorescent signal detection device has compact structure and simple and reliable light path system.

The invention discloses a pin moving device which comprises a pin, a rotary power unit and a driving member arranged in the rotary power unit, wherein, the pin and the driving member are in fixed connection, or the pin and the driving member are of a one-piece structure, the rotary power unit is used for driving the driving member and the pin to rotate along a circumferential direction of the pin and simultaneously driving the driving member and the pin to move forward or backward along the axial direction of the pin, and the pin and the driving member are arranged along a coaxial line. The invention also discloses a movable connecting structure having the pin moving device and a suspension hook structure. The invention enables the technical problem in the prior art that it is difficult to install a pin because a great frictional force between the pin and the inner wall of an installing hole needing to be installed with the pin to be overcome, and enables the problem that a large-size and great-weight suspension hook is prone to making integral transportation of the suspension hook exceed national restrictions on transportation weight and size to be overcome.

The invention discloses a fuse for wind power protection and a replacement method of a fusing feedback device of the fuse. According to the main point of the technical scheme, the fuse comprises an installation base for installing a fuse link; the installation base is provided with the fusing feedback device; the fusing feedback device comprises a trigger, a linkage mechanism and an interaction mechanism; the trigger is connected with the fuse link in parallel; the voltage on the trigger is increased when the fuse link is fused; when the fuse link is fused, the trigger actuates the linkage mechanism to generate an action; the action of the linkage mechanism triggers the action of the interaction mechanism; and the action of the interaction mechanism is converted into an electric signal and is transmitted to an external data interface. The electric signal is transmitted to the positions of a monitor room and the like through a microswitch according to the fusing condition of the fuse link; multiple pieces of position information can be timely and accurately obtained by power maintenance personnel; and field investigation is not needed, so that manpower is saved; and the efficiency is improved.

The invention discloses a prestressed reinforced concrete precast column vertical connecting structure and a construction method thereof. The prestressed reinforced concrete precast column vertical connecting structure comprises an upper-layer reinforced concrete prefabricated column, a lower-layer reinforced concrete prefabricated column, a steel bar connector, a leveling positioner and a sealinggrouting material, an anchoring space for accommodating the steel bar connector is formed in the bottom end of the upper-layer reinforced concrete prefabricated column; lower-layer column prestressedribs and upper-layer column prestressed ribs do not make contact in the steel bar connector, the leveling positioner is arranged on the top end face of the lower-layer reinforced concrete prefabricated column, the bottom end face of the upper-layer reinforced concrete prefabricated column abuts against the positioner, an initial tensioning gap is formed between the upper-layer reinforced concreteprefabricated column and the upper-layer reinforced concrete prefabricated column, and the initial tensioning gap is filled with the sealing grouting material. The pre-stress principle of pre-stresssteel bars is utilized, and standing and positioning of the columns are achieved through initial tensioning of the pre-stress steel bars in cooperation with the leveling positioner; and then through complete tensioning, reliable connection of the columns and the overall lateral performance and self-resetting performance of the structure are ensured.

The invention relates to a packaging method and device. The method includes the steps that a binding agent is formed in a packaging region of a display substrate; an organic film is formed on the binding agent; pressure is exerted on the organic film and the binding agent, wherein the organic film does not adhere to equipment for exerting force; the organic film is removed; a cover plate is pressed on the binding agent. According to the technical scheme of the embodiment, the organic film can be formed on the binding agent after the binding agent is formed, then pressure is exerted on the binding agent through the organic film, the contact face between the binding agent and the display substrate is flat, a good packaging effect is ensured, and it is avoided that newton rings or other poor display problems occur in the packaging region in the follow-up display process.

The invention provides a super-thick carbon oil printing special composite screen printing plate and a manufacturing method thereof. The manufacturing method of the special composite screen printing plate comprises the following steps of (1) fully wetting a composite steel mesh with water; (2) pasting a layer of aqua film to the back surface of the composite steel mesh and baking the composite steel mesh in a drying oven; (3) tearing off an aqua film protective film, coating the surface of the aqua film with light sensitive paste and then drying the aqua film; and (4) conducting exposure and development to obtain the super-thick carbon oil printing special composite screen printing plate comprising the steel mesh, the aqua film layer and the light sensitive paste layer arranged in sequence. Through the screen printing plate, the problem that a short circuit is caused by carbon oil leakage due to the fact that the middle of a mesh screen is empty in the traditional screen printing plateprinting process is solved; the edge of carbon oil is more regular and smooth; deckle edges are avoided in the printing process; the printing quality is guaranteed better.

The invention belongs to the technical field of PU synthetic leather, and particularly relates to high-abrasion-resistance PU synthetic leather and a preparation method thereof. The PU synthetic leather comprises a base fabric layer, a coating and release paper; the base fabric layer is made of a non-woven fabric material and adopts a double-layer composite material, and the upper surface of the base fabric layer is covered with the coating; the coating is divided into a cortex coating and a skin coating; the upper surface of the base fabric layer is covered with the cortex coating; and the upper surface of the skin coating is bonded with the release paper. Through the high-abrasion-resistance PU synthetic leather and the preparation method thereof, it is effectively achieved that PU synthetic leather is washable, small in quality change, not prone to generating static electricity, high in strength and excellent in antibacterial performance, meanwhile, the stable electromagnetic shielding performance is achieved, moreover, the abrasion resistance of a PU coating is substantially improved, pinholes are not prone to being generated after the surface of the leather is rubbed, and thebeauty of the appearance can be kept for a long time during using.

The invention discloses a plate feeding table, which comprises a support, wherein a worktable is arranged on the support; and a supporting and conveying device is arranged on the worktable. The 360-degree omni-directional multi-degree-of-freedom conveying can be realized; round balls are adopted as rolling carriers, with smoother contact surface and smaller friction, the plate feeding table has the advantage of creating convenience in conveying and reducing abrasion to the surfaces of plates; and the detachable way is adopted and the round balls can be conveniently replaced after being abraded, therefore the plate feeding table has high convenience.

The invention discloses a building formwork pull rod which comprises a pull rod body arranged between two building formworks. The pull rod body comprises a rod body and connecting portions arranged at two ends of the rod body respectively, cross section of the rod body is round, diameters of sections of two ends of the rod body are unequal, and the rod body forms a conical structure, with a certain oblique angle, similar to die drawing design in a die. After concrete is solidified, the pull rod body can be taken out by knocking from one end smaller in diameter to the other end, larger in diameter, of the rod body, so that great convenience in taking out is realized; sleeving of plastic pipes is not needed, so that a lot of plastic pipes are saved, mounting process of the pull rod is simplified, and cost is lowered greatly; a contact face of the pull rod and a wall is smooth, so that the building formwork pull rod is good in sealing effect during repairing and less prone to water leaking.

The invention discloses an electric hair trimmer comprising a cutter head unit, a motor, a rotating shaft, and a power source. The cutter head unit comprises a fixed cutter unit, a moving cutter unit and a fine adjustment mechanism. The moving cutter unit is arranged above the fixed cutter unit. The moving cutter unit comprises a moving cutter and a moving cutter drive rack. The fine adjustment mechanism comprises an adjusting block and a torsion spring arranged on the same. Two ends of the torsion spring are inserted onto the moving cutter drive rack, so that the moving cutter has a degree of freedom of motion, rocking left and right and sliding back and forth relative to the fixed cutter unit. The upper surface of the fixed cutter unit is provided with a grinding bar or a grinding layer. The grinding bar or grinding layer is disposed on the upper surface of the fixed cutter unit, so that the trimmer has the function of blade sharpening; when the shearing sharpness of the cutter head decreases, the cutter head can be ground with the grinding bar or grinding layer and kept sharp, hair-cutting efficiency is improved, the service life of the cutter head is greatly prolonged, and cost is saved.

The invention discloses gastrointestinal surgical scissors. The gastrointestinal surgical scissors comprise a scissor body A and a scissor body B the middles of which are connected with each other through a hinge shaft, the bottom of the scissor body A and the bottom of the scissor body B are both provided with finger rings, a sliding column is installed on the hinge shaft on the surface of the scissor body B, an auxiliary rod is installed on the scissor body B through the sliding column, the middle of the auxiliary rod is provided with a bevel groove, the sliding column is installed in the bevel groove, the top of the auxiliary rod is provided with an arc hook, the tail portion of the auxiliary rod is provided with a contact plate, and the back side of a blade of the scissor body B is provided with a replacement hook. By means of the gastrointestinal surgical scissors, the separation of the gastrointestinal tracts and accurate shearing and connection of target positions are achieved with one hand during a surgery.

The invention relates to the technical field of wind power flange machining, in particular to a clamping mechanism for wind power flange radial drilling. The supporting plate at least comprises a fixing plate, a positioning plate is arranged on one side of the fixing plate, mounting plates are mounted on the surfaces of the fixing plate and the positioning plate, a positioning block is arranged on the surface of the positioning plate, a screw is arranged between the positioning block and one mounting plate, the driven part at least comprises a driven wheel, and the driven wheel rotates on the surface of the supporting plate. The side face of the driven wheel is connected with a rack in a meshed mode, the rack is fixedly connected with the driving arm, an annular pasting plate is arranged above the driven wheel, and the bottom face of the protrusion is elastically connected with the annular pasting plate through a spring. The wind power flange is driven to rotate through rotation of the annular flitch plate, a local drill hole of the wind power flange deviates from the current position, chippings in the drill hole fall into the gap, and chippings of the fixing plate and the positioning plate fall into the gap in a statistical mode through rotation and friction of the wind power flange.

The invention discloses a riveting square jig, comprising a synchronous driving structure and a riveting mechanism. The synchronous driving mechanism comprises a cylinder, a bottom plate, a movable plate and support columns, the cylinder is arranged under the bottom plate, a piston rod of the cylinder penetrates through the bottom plate and is connected with the bottom of the movable plate, a hole for placing a gold needle is arranged in the center of a placing plate, a baffle plate is arranged on each of four sides of the placing plate, each baffle plate is internally provided with a sliding groove used for placing a sliding arm, four sliding arms are arranged on the movable plate, cam rollers are in sliding contact with sliding surfaces of the sliding arms and are connected with movable blocks through fixed rods, fixed arms are arranged on the movable blocks, and tension springs are mounted between the fixed arms and side walls of the baffle plates. The riveting square jig provided by the invention is simple in structure, convenient to use, fast in return speed, and accurate in return, and can move four riveting plates at the same time, processing quality is improved, manufacturing costs are relatively low, and the length of the gold needle can be prevented from being elongated.

The invention relates to a cooling plate for an electric energy storage element, said cooling plate comprising at least two non-detachably interconnected metal sheets and at least one plastic covering. The joined metal sheets comprise at least one cooling channel which can be created by separating means.

The invention provides a cooling disc body with an internal annular channel and a preparation method of the cooling disc body. The cooling disc body comprises a main plate and a cover plate, annular grooves are evenly formed in the main plate, the cover plate is used in cooperation with the main plate and covers one side of the annular grooves in the main plate, and the annular grooves form the internal annular channel of the cooling disc body; and the whole cooling disc body is in a volute shape and comprises a volute body and a volute inlet, and the inlet and the outlet of the annular channel are formed in the volute inlet and communicate with the outside. Through the structural design of the annular channel in the cooling disc body, the contact surface between the cooling disc body and a to-be-cooled product is smooth, the contact area is large, cooling mediums can be uniformly distributed and rapidly circulate, and the product is rapidly cooled; and the cooling disc body is reasonable in structural design, simple and convenient in preparation process, good in sealing performance and high in product percent of pass, reworking operation can be greatly reduced, the production cost is reduced, and application to high-precision product cooling is facilitated.

The invention discloses an automobile tire chain. The automobile tire chain comprises one group of spliced chain section units; the chain section units are octagonal steel rings; the chain section units are spliced with each other in a transverse direction and a longitudinal direction in sequence to form a rectangular chain; the adjacent chain section units are connected with each other through connecting parts; the connecting parts are two chain section sleeves which are arranged in parallel; the two chain section sleeves are matched with two side edges of the connected chain section units; the length of the rectangular chain is adaptive to the perimeter of a tire; the width of the rectangular chain is adaptive to the width of the tire; and two wide edges of the rectangular chain are respectively provided with connecting hooks matched with each other. The tire chain is encircled on the automobile tire and fixed by the connecting hooks; as honeycomb splicing structures are formed between the chain section units, the tire chain and the tire can fit closely together on the premise of ensuring the skid resistance and stability, and the friction between the tire chain and the tire is reduced; and moreover, breakage of the tire chain can be avoided to ensure driving safety. The automobile tire chain is convenient to detach and mount, easy to store and convenient to carry along with automobiles.

The invention relates to an In2Te3 phase-change memory element and a preparation method thereof. The In2Te3 phase-change memory element is characterized in that an In2Te3 membrane is adopted as phase-change memory storage material, wherein the In2Te3 membrane is in an amorphous state at room temperature and is in a crystalline state after anneal at 450-470 DEG C, the basic configuration of the phase-change memory element is of a three-layer structure which is formed in such a way that one layer of In2Te3 membrane is clamped between a top electrode film and a bottom electrode film, and the top electrode film and the bottom electrode film respectively lead out wire leads made of spun gold or brass wires. The invention realizes the switching effect in tests and has the characteristics that the differences of resistance values of the In2Te3 membrane in an amorphous state and in a crystalline state are obvious and can reach 3-4 orders of magnitude; the phase-change speed / read-write speed is fast, the working volt is low, and the needed voltage pulse achieves ns magnitudes; and a plurality of circular changes can be made between a high-impedance state and a low-impedance state.

An embodiment of the invention provides a reflector plate, a backlight module and a display device. The reflector plate comprises a base layer, a reflecting layer and a flatness adjusting layer. The reflecting layer is arranged on the base layer, and the flatness adjusting layer is arranged under the base layer; the flatness adjusting layer is used for keeping the surface, which is close to the base layer, of the flatness adjusting layer flat. The reflector plate, the backlight module and the display device have the advantage that the problem of white spot defects due to the fact that an existing reflector plate rubs with optical net points of light guide plates can be solved.

The invention discloses a distribution transformer cover plate which relates to the technical field of transformer devices. The distribution transformer cover plate comprises a square cover plate body and is characterized in that the upper cover surface of the cover plate body is a flat end surface, four sides of the cover plate body respectively extend by 60mm to be used as flanges, four corners of the flanges are respectively provided with a gap, and front 30-mm parts of the four flanges are inwards bent to form included angles of 90 DEG, so that edges are formed. The distribution transformer cover plate is flat, and is little in deformation of boat shape and waves, attractive in appearance and little in labor intensity; a temporary reinforcing rib is not needed to be welded or the thickness of a steel plate is not needed to be increased. The contact surface of the distribution transformer cover plate and a box edge sealing member is flat, the compression amounts of sealing members are consistent, and the leakage probability is reduced.

The invention relates to a groove type ironing machine and belongs to the technical field of ironing machines. The groove type ironing machine comprises an ironing groove group, each ironing groove is in an arc shape with an upward arc opening, the ironing groove group comprises at least one rigid groove and at least one flexible groove, and transition grooves with downward arc openings are between the ironing grooves. The first ironing groove of the ironing groove group is a rigid groove, the second ironing groove is a flexible groove, a transition groove between the first ironing groove and the second ironing groove is a first transition groove, the rigid groove is provided with a transverse steam chamber partition fixedly arranged at the longitudinal middle position of an outer arc panel of an inner groove plate in the transverse direction, at least one longitudinal steam chamber partition is arranged between outer arc panels of the inner groove plate in the longitudinal direction to divide the ironing grooves into at least four steam chambers, each steam chamber is provided with a steam branch pipe respectively, and the steam branch pipe is communicated with a steam main pipe for centralized supply of steam. The groove type ironing machine is further provided with an adjustable pressurization system. The groove type ironing machine greatly improves ironing effect under the conditions that steam pressure is limited.

The invention provides a novel dough mixer. The novel dough mixer adopts a horizontal screw type structure, and comprises a motor, a supporting frame and a material barrel, wherein the supporting frame is arranged below the material barrel; a screw type blade is arranged inside the material barrel; a feeding hole and a water charging hole are arranged above the material barrel; a discharging hole is arranged on one side below the material barrel; the motor is arranged on the supporting frame and on one side of the material barrel; the motor is connected with the screw type blade by a gear mechanism; a transparent partition plate is arranged outside the gear mechanism; and a smooth ceramic layer is respectively arranged on the inner wall of the material barrel and the outer surface of the screw type blade. The novel dough mixer has such advantages that the structure is simple, flour is not easy to adhere, dough mixing is safer and more sanitary, and the like.

The invention discloses a semiconductor structure and a forming method thereof. The forming method includes the following steps of: forming a doped layer in a substrate or on the surface of the substrate, wherein the substrate exposes the side wall of the doped layer; forming a sacrificial layer on the surface of the side wall of the doped layer exposed by the substrate; forming a dielectric layeron the substrate and the doped layer, wherein the dielectric layer covers the side wall of the sacrificial layer; forming a first trench in the dielectric layer, wherein the bottom of the first trench exposes the top of the doped layer and the top of the sacrificial layer; after the first trench is formed, removing the sacrificial layer, and forming a second trench at the bottom of the first trench; forming a metallide on the surface of the doped layer exposed by the first trench and the second trench; and after the metallide is formed, forming plugs in the second trench and the first trench.According to the forming method, the resistance between the plugs and the doped layer can be reduced, and the performance of the semiconductor structure can be improved.

The invention provides an MPO multifilament drawing auxiliary device with ultrahigh squareness. The device is arranged on the end surface of a drawing furnace and comprises: an outer clamp; an inner clamp, wherein the size of the inner clamp is smaller than that of the outer clamp, and the outer clamp and the inner clamp are installed diagonally, so that the outer clamp at least partially clamps the inner clamp, and a square enclosure is formed between the outer clamp and the inner clamp; a plurality of sliding blocks arranged in the square enclosure, wherein every two of the sliding blocks are adjacent to form a square hole located in the center; and through L-shaped grooves arranged on each edge of the outer clamp and the inner clamp and pushing mechanisms arranged in the L-shaped grooves, wherein the pushing mechanism can be switched between a locking state and a releasing state in the L-shaped groove, in the releasing state, a pushing rod is acted by a clamping spring and located in one side of a sliding groove in the direction perpendicular to the side face of the sliding block, contacts with the corresponding sliding block and is pressed, and in the locking state, the pushingrod is operated to overcome the elastic force of the clamping spring, and the pushing rod and the sliding block are clamped on the other side of the L-shaped groove, so that the overall squareness isguaranteed.