39results about How to "Guaranteed vertical installation" patented technology

The invention relates to a fabricated wall body included angle adjusting device which comprises a shaft rod erected at an included angle of wall bodies, and the shaft rod, a bottom beam and an obliquebeam form a triangular supporting structure. A through hole is formed in the outer end of the bottom beam, an arc-shaped telescopic beam is installed in the through hole, sliders are arranged at thetwo ends of the arc-shaped telescopic beam, the slider at one end of the arc-shaped telescopic beam is arranged at the bottom of the left wall body, and the slider at the other end is arranged at thebottom of the right wall body; a construction method of the fabricated wall body included angle adjusting device comprises the steps of sleeving the shaft rod with a wall fixator, and connecting the left wall body firstly; connecting the right wall body; pulling telescopic rods out of a guide groove, and inserting L-shaped supporting plates of the sliders at the ends of the two telescopic rods into the bottoms of the wall bodies separately; rotating supporting lead screws of universal wheels to enable the universal wheels to touch the ground, and continuing screwing the supporting lead screwsof the universal wheels to enable the L-shaped supporting plates to slightly lift the wall bodies; adjusting the included angle, and then fixing the free ends of the wall bodies; and fixing a lockingassembly at the included angle. According to the fabricated wall included angle adjusting device, the adjustment of the wall body is labor-saving, the installation precision of the wall body is high,and the speed is high.

The invention discloses a root key construction device for a root pouring pile. A hydraulic cylinder is fixed to the position above the center of a base plate. The end portion of a hydraulic rod of the hydraulic cylinder downwards stretches out towards the base plate. A plurality of vertical push rods are evenly distributed on the part, around the hydraulic cylinder, of the base plate. The hydraulic rod is connected with the vertical push rods through a connecting rod mechanism, the vertical push rods move in the radial direction of the base plate, the positions, corresponding to the vertical push rods, of the edge of the upper surface of the base plate are provided with root key limiting devices, and the root key axis points at the axis of the base plate through the root key limiting devices and moves in the radial direction of the base plate. The positions, corresponding to the root key limiting devices, of the bottom of the base plate are rotationally connected with transmission gears, the transmission gears are in transmission connection with respective drive motors, and the transmission gears are in engaged transmission with vertical racks at the tail ends of root keys inserted in the side wall of a pile pit. It can be known from the above structure, the root key construction device for the root pouring pile can construct all root keys on one layer at the same time, automatic ascending in the pile pit can be achieved without the aid of external force so that construction of all the root keys in the pile pit can be finished, and the root key construction efficiency is improved.

The invention discloses a construction platform for facilitating root key construction of a root type cast-in-place pile. The construction platform for facilitating the root key construction of the root type cast-in-place pile comprises a base plate; the positions, corresponding to root key limiting devices, of the bottom of the base plate are respectively and rotatably connected with transmission gears; the transmission gears are respectively in transmission connection with respective driving motor; the transmission gears are in engaged transmission with vertical gear racks at the tail ends of the root keys which are inserted into the side wall of a pile pit. From the above structure, the construction platform for facilitating the root key construction of the root type cast-in-place pile disclosed by the invention can climb in the pile pit automatically so as to complete the construction of all root keys in the pile pit without external force, so that the construction efficiency of the root keys is improved.

The invention discloses a porous medium permeability testing device, which is composed of a first gas source module, a reactor module, a backflow module, a vacuum-pumping module, a gas-liquid separation module and a mesh plate template. With the arrangement of a device capable of rapidly guaranteeing vertical installation of reactors and by the mode of arranging multiple reactors, the problem that existing devices cannot be applied in reaches on permeability of porous mediums is solved. By the use of the device, laboratory testing researches on permeability rules of a porous medium can be realized.

The invention discloses a small hydraulic buffer impact test method and device, and the method comprises the following steps: first, a small hydraulic buffer is vertically fixedly arranged, a buffer rod is vertically upward, an impact load and the hydraulic buffer are arranged on a same vertical line, and the impact load is arranged on a set height above the hydraulic buffer; the impact load freely falls onto the hydraulic buffer for drop-hammer impact; a plurality of different buffer state images in the buffer process of the hydraulic buffer can be obtained by use of a high-speed camera; and finally, the number of the shot images in the buffer process can be obtained by analytic statistics by use of dichotomy, and the buffer time of the hydraulic buffer can be obtained by dividing the number of the shot images by shooting frame rate of the high-speed camera. Through measuring the buffer time of the small hydraulic buffer for further obtaining the mechanical system actuation time, the buffer property of the hydraulic buffer can be judged, the method is simple, and test results are accurate.

The invention provides a steel strand mounting method for a wind driven generator supporting tower frame prestressed structure. The steel strand mounting method includes the steps that tower top anchorage devices and tower bottom anchorage devices are mounted; single steel strands are pulled into target tower bottom anchor holes through a winch, and tower bottom clamping pieces are used for anchoring; steel strands are pulled into target tower top anchor holes, and tower top clamping pieces are used for anchoring the steel strands; the target tower top anchor holes and the target tower bottomanchor holes are converted until a first preset number of target tower top anchor holes and a first preset number of target tower bottom anchor holes are hung and anchored; and the tower top anchoragedevices and the tower bottom anchorage devices are converted until a second preset number of tower top anchorage devices and a second preset number of tower bottom anchorage devices are hung and anchored. The steel strands are mounted in the manners of single hanging and tensioning and opposite angle mounting, the mounting efficiency is high, the safety coefficient is large, the energy consumption is low, mounting is stable, the problems of mutual twisting, winding and interfering between the mounted steel strands are solved, the height of a foundation inner cavity of a tower barrel is reduced, and the material cost, the construction cost and the labor cost are reduced.

The invention particularly relates to a grouting pipe reinforcing and grouting structure and a construction method thereof. The grouting structure comprises a grouting pipe, and a soil breaking mechanism arranged on the grouting pipe. The soil breaking mechanism comprises a fixed part fixedly sleeving the grouting pipe, a sliding pipe part and a soil breaking assembly, the sliding pipe part sleeves the position, above the fixed part, of the grouting pipe and is in sliding fit with the grouting pipe, and the soil breaking assembly is arranged between the fixed part and the sliding pipe part. When the sliding pipe part slides in the fixed direction, the soil breaking assembly can expand out in the axis direction away from the grouting pipe. Slurry output grooves corresponding to the positions of slurry output holes formed in the grouting pipe are formed in the outer surface of the sliding pipe part. The invention correspondingly discloses the construction method of the grouting structure. According to the grouting pipe reinforcing and grouting structure and the construction method thereof, the slurry output size of the grouting pipe can be increased, and therefore slurry output by the grouting pipe can permeate into the soil layer around the pipe, and the slurry output effect of the grouting pipe and the connecting stability of the grouting pipe and the soil layer around the pipecan be improved.

The invention discloses a rootkey construction method of a rootkey construction device utilizing a root type cast-in-place pile. A substrate is hoisted to the pit bottom, a hydraulic rod is made to downwards stretch out of a hydraulic cylinder, a pressing plate A is driven to downwards press towards one side of a pressing plate B, a connection rod A and a connection rod B outwards push a connection block and a vertical push plate, and the vertical push plate is made to horizontally jack rootkeys into the side wall of a pile pit; after the rootkeys are jacked into the side wall, the hydraulic rod is made to retreat to the hydraulic cylinder; operators position vertical racks and steel bars of the rootkeys, it is guaranteed that the vertical racks are straight, the vertical racks and the tail ends of the rootkeys are fixed, and the vertical racks are made to be meshed with corresponding transmission gears; and when all the rootkeys on a certain layer are fixedly provided with the vertical racks, drive motors are started to drive the transmission gears to climb upwards along the vertical racks. It is known through the above steps that by means of the rootkey construction method of the rootkey construction device utilizing the root type cast-in-place pile, all the rootkeys on the same layer can be constructed simultaneously, climbing in the pile pit can be performed automatically without depending on external force so as to complete construction of all the rootkeys in the pile pit, and construction efficiency of the rootkeys is improved.

The invention discloses a fast detection device for a spatially continuous bent pipe, which comprises a base plate, wherein the base plate is equipped with a reference positioning module, a first ellipticity detection module, a second ellipticity detection module, a first resilience detection module and a second resilience detection module, wherein the bent pipe is erected on the reference positioning module, the first ellipticity detection module, the second ellipticity detection module, the first resilience detection module and the second resilience detection module. The fast detection device can quickly detect two molding indicators such as the ellipticity and the resilience of the metal bent pipe, and has the characteristics of easy adjusted of the detection range, high working efficiency and low cost.

The invention relates to a full-automatic assembly machine for bolts. The machine comprises a worktable, and a frame fixedly mounted on the worktable. The machine is characterized by further comprising an assembly mechanism for assembling the bolts, automatic loading mechanisms arranged on the two sides of the assembly mechanism, and supporting parts for supporting the bolts in the assembly process; the assembly mechanism is arranged on the frame through a transverse driving mechanism in a transverse sliding mode; the automatic loading mechanisms are fixedly mounted on the worktable; the supporting parts are arranged on the worktable right under the assembly mechanism; and the worktable is provided with a qualified conveying channel and an unqualified conveying channel. The machine realizes automatic assembly, and achieves high assembly efficiency and good assembly effect.

The invention discloses a pulp bleaching device for packaging paper. The device comprises a reaction kettle and a reaction tank. The reaction kettle is installed in the reaction tank; the reaction tank is installed on a base; the reaction kettle is a cylindrical structure, and the outer side of the reaction kettle is surrounded by a heating pipe; a mounting ring plate and a mounting strip plate are arranged in the reaction kettle; the mounting ring plate is provided with a high-pressure nozzle hole; a pushing device is arranged in the reaction tank; and the upper inner side wall of the reaction tank is provided with an air inlet hole, which is communicated with a steam generator through an intake pipe. The device has a high-efficiency bleaching effect. By the device, paper pulp can be fully contacted with a bleaching agent; the bleaching time can be saved and the bleaching process can be simplified; the damage to the fiber structure of paper pulp by multiple operation steps is reduced,and the original quality of paper pulp can be guaranteed; the bleaching efficiency can be improved; equipment investment and floor space are reduced; and the production cost is reduced.

The invention discloses an automatic locking screw machine capable of correcting deviation for a computer case. With the matching of the driving structure, the automatic locking screw machine can automatically align the bolt holes of the components with the mounting holes of the chassis when installing the circuit board and other components in the computer case, so as to avoid the bolt holes and the mounting holes of the case after the components are offset. If the mounting holes are not aligned, screwing in the screws will cause the screws to not be fully screwed in and cause floating. The components can be stably installed in the case, which effectively improves the quality of the computer case installation and ensures the service life of the computer.

The invention discloses an ultrasonic gauge which comprises a U-shaped pipeline with two ends, an electronic circuit, a first shell, a second shell and more than two ultrasonic transducers. The first shell is used for accommodating the electronic circuit, the second shell is used for accommodating the U-shaped pipeline, and the ultrasonic transducers are connected to the electronic circuit by corresponding wires; the waterproof ultrasonic transducers are penetratingly arranged on the inner wall of the U-shaped pipeline in the second shell and are in direct contact with liquid in the U-shaped pipeline. The ultrasonic gauge has the advantages that the ultrasonic transducers can be in direct contact with the metered liquid and can be assuredly perpendicularly mounted, and information can be accurately received by the transducers in an opposite transmission manner.

The invention discloses a root key construction device for a root pouring pile. A hydraulic cylinder is fixed to the position above the center of a base plate. The end portion of a hydraulic rod of the hydraulic cylinder downwards stretches out towards the base plate. A plurality of vertical push rods are evenly distributed on the part, around the hydraulic cylinder, of the base plate. The hydraulic rod is connected with the vertical push rods through a connecting rod mechanism, the vertical push rods move in the radial direction of the base plate, the positions, corresponding to the vertical push rods, of the edge of the upper surface of the base plate are provided with root key limiting devices, and the root key axis points at the axis of the base plate through the root key limiting devices and moves in the radial direction of the base plate. The positions, corresponding to the root key limiting devices, of the bottom of the base plate are rotationally connected with transmission gears, the transmission gears are in transmission connection with respective drive motors, and the transmission gears are in engaged transmission with vertical racks at the tail ends of root keys inserted in the side wall of a pile pit. It can be known from the above structure, the root key construction device for the root pouring pile can construct all root keys on one layer at the same time, automatic ascending in the pile pit can be achieved without the aid of external force so that construction of all the root keys in the pile pit can be finished, and the root key construction efficiency is improved.

The invention discloses an anti-theft panoramic cloud monitoring device with an automatic alarm function. The device comprises a video recorder, Camera, display and alarm, The camera is electrically connected with the video recorder through a first transmission line. The display is electrically connected with the video recorder through a second transmission line. the camera is fixed on the mounting surface through a connecting mechanism; a supporting seat is fixedly mounted at the bottom of the display; A power interface is formed in the position, close to one side, of the rear surface of thevideo recorder, a plurality of network cable interfaces are formed in the position, close to the middle, of the rear surface of the video recorder, a plurality of USB interfaces and video interfaces are formed in the position, close to the other side, of the rear surface of the video recorder, and a mounting base is connected to the bottom of the video recorder. According to the anti-theft panoramic cloud monitoring equipment with the automatic alarm function, it can be guaranteed that a camera can be vertically installed during hoisting and wall mounting, and the stability of a video recorderduring placement can be improved.

The invention specifically relates to a grouting pipe reinforcement grouting structure and a construction method thereof. The grouting structure includes a grouting pipe and a soil-breaking mechanism arranged on the grouting pipe; The fixed part of the grouting pipe is sleeved on the grouting pipe above the fixed part and the sliding pipe part is slidably matched with the grouting pipe, and the soil breaking assembly is arranged between the fixed part and the sliding pipe part; the sliding pipe part faces the fixed part When sliding in the same direction, the soil-breaking assembly can expand toward the axis away from the grouting pipe; the outer surface of the sliding pipe is also provided with a grouting groove corresponding to the position of the grouting hole set on the grouting pipe; the present invention also discloses correspondingly A construction method of grouting structure is proposed. The grouting pipe reinforcement grouting structure and its construction method in the present invention can increase the grouting volume of the grouting pipe, and enable the slurry output from the grouting pipe to penetrate into the soil layer around the pipe, so as to improve the grouting pipe. Slurry effect and connection stability with the soil around the pipe.

The invention discloses a rootkey construction method of a rootkey construction device utilizing a root type cast-in-place pile. A substrate is hoisted to the pit bottom, a hydraulic rod is made to downwards stretch out of a hydraulic cylinder, a pressing plate A is driven to downwards press towards one side of a pressing plate B, a connection rod A and a connection rod B outwards push a connection block and a vertical push plate, and the vertical push plate is made to horizontally jack rootkeys into the side wall of a pile pit; after the rootkeys are jacked into the side wall, the hydraulic rod is made to retreat to the hydraulic cylinder; operators position vertical racks and steel bars of the rootkeys, it is guaranteed that the vertical racks are straight, the vertical racks and the tail ends of the rootkeys are fixed, and the vertical racks are made to be meshed with corresponding transmission gears; and when all the rootkeys on a certain layer are fixedly provided with the vertical racks, drive motors are started to drive the transmission gears to climb upwards along the vertical racks. It is known through the above steps that by means of the rootkey construction method of the rootkey construction device utilizing the root type cast-in-place pile, all the rootkeys on the same layer can be constructed simultaneously, climbing in the pile pit can be performed automatically without depending on external force so as to complete construction of all the rootkeys in the pile pit, and construction efficiency of the rootkeys is improved.

The invention relates to a pipe fitting connecting device, which comprises a connecting body. The connecting body comprises a base body portion and an upper connecting portion. A lower connecting hole for connecting a lower pipe fitting is formed in the base body portion, while an upper connecting hole for connecting an upper pipe fitting and coaxially communicating with the lower connecting hole is formed in the upper connecting portion, and the upper connecting hole is larger in diameter than the lower connecting hole. A mounting cap is arranged on an upper end of the upper connecting portion, and an orifice for an upper pipe fitting to pass therethrough is formed in the mounting cap. A sealing clip is arranged on an upper surface of the mounting cap and used for sealing a gap between the orifice and an upper pipe fitting. While an upper pipe fitting is mounted, a bottom end of the upper pipe fitting is inserted into the upper connecting hole through the orifice in the mounting cap, and capable of radially moving in the upper connecting hole; then, the gap between the orifice and the upper pipe fitting is sealed by using the sealing clip. The pipe fitting connecting device provided by the present invention provides a large radial moving range for an upper pipe fitting in the upper connecting hole, and thus can guarantee vertical installation of the upper pipe fitting to an utmost extent.

The invention discloses a RF antenna pedestal with good stability.The RF antenna pedestal comprises a mounting base, wherein an RF antenna pedestal body is disposed at a midpoint on the top of the mounting base; an annular fixing plate is fixedly connected to the surface of the RF antenna pedestal body; a lantern ring is disposed on the surface of the RF lantern ring body and located on the top ofthe annular fixing plate; the two sides of the top surface of the lantern ring are fixedly connected with a handle through first connecting rods; the left and right sides of the lantern ring are fixedly connected to an adsorption fixing device through connecting posts; the adsorption fixing device comprises a sleeve; two sides of the top of the sleeve are fixedly connected with a connecting platethrough second connecting rods; and a threaded rod is arranged at a midpoint on the top of the connecting plate. The RF antenna pedestal with good stability is reasonable in structural design and convenient to use, can ensure that the antenna is installed vertically so as to achieve the best effect, ensures signal transmission, and expands the use range of the RF antenna.

The invention discloses an easy-to-install windmill based on wind energy conversion technology, comprising a generator set, a supporting rod for fixing the generator set and a base for limiting the supporting rod, wherein a wing is installed at one end of the generator set and two clamping blocks are arranged on the base; an adjusting block is fixed at the lower end of the supporting rod, and connecting blocks are arranged on both sides of the adjusting block and are rotatably connected to the two clamping blocks; the adjusting block is provided with a limiting hole, the two clamping blocks are respectively provided with first connecting holes and second connecting holes, and a limiting rod sequentially passes through the first connecting holes, the limiting hole and the second connectingholes to fix the supporting rod and the base. The supporting rod and the base are rotatably connected by the adjusting block at the lower end of the supporting rod and the two clamping blocks on the base; after the base is fixed, the supporting rod can be pulled up by means of a traction rope and the like, and then the limiting rod passes through the two clamping blocks and the adjusting block tofix the supporting rod and the base relatively, thus completing the installation of the entire windmill. The entire installation process is simple and convenient and easy to implement, and the installing difficulty of the windmill is reduced.

The invention discloses a new energy vehicle battery module. The base connecting plate is fixed on the equipped vehicle, the front part is fixed with a support vertical plate assembly, and the rear part is fixed with several battery modules. The upper parts of several battery modules pass through the battery module. The group connection components are connected and fixed. The support vertical plate component includes a moving end and a fixed end. The moving end can rotate around the fixed end. There are several connecting protrusions evenly distributed on the two opposite sides of the BMU, and several connecting protrusions are arranged on the other side. end, the connecting end is connected with the insertion end, and the connecting protrusion is fixed with the moving end through bolt connection. The first matching protrusion, the second matching protrusion and the third matching protrusion are respectively connected with the first groove, the second The groove and the third groove are mated and connected, and the fixing protrusion is mated and fixed with the clamping opening. The invention can ensure the corresponding installation of the plug and the BMU joint, avoid damage to the pins, and improve product quality. The invention is suitable for wide application in new energy vehicles.

The invention discloses a concentrating photovoltaic power generation matrix and system convenient to install. The concentrating photovoltaic power generation matrix comprises a fixed plate and an adjusting unit, mounting holes are formed in four corners of the upper surface of the fixing plate; the adjusting unit is arranged in the middle of the upper surface of the fixing plate, the upper end of the adjusting unit is rotationally connected with a supporting seat, the upper end of the supporting seat is rotationally connected with a rotating seat through a bearing, the upper end of the rotating seat is rotationally connected with a third rotating shaft, and the outer arc surface of the third rotating shaft is fixedly connected with the inner arc wall of the lower end of a supporting block; the upper surface of the supporting frame is provided with gallium arsenide solar cells which are uniformly distributed, the upper surface of the supporting frame is provided with Fresnel lenses which are uniformly distributed through a supporting shell, and the Fresnel lenses are respectively matched with the gallium arsenide solar cells; the concentrating photovoltaic power generation matrix convenient to install is high in power generation efficiency, convenient to level during installation, and simple and convenient to install.

The invention relates to an L-shaped assembly system for installing thermal insulation and decoration integrated panels, including an L-shaped connecting plate, an L-shaped fixing plate and an L-shaped supporting plate. The L-shaped connecting plate is divided into an upper connecting plate and a lower connecting plate. plate; the upper connecting plate and the lower connecting plate are respectively fixed above and below the inner side of the decorative board, the L-shaped fixing plate and the L-shaped support plate are respectively fixed above and below the outer side of the wall, and the upper connecting plate and the lower connecting plate are respectively connected to the L The L-shaped fixing plate and the L-shaped support plate are connected by bolts, the L-shaped support plate is provided with a horizontal support platform, and the bottom surface of the decorative plate is in contact with the top surface of the support platform. The invention has the advantages of simple structure, small volume, light weight, low cost, firm and convenient installation.

The invention discloses a transmission mechanism capable of automatically adjusting concentricity. A clutch is freely arranged, a first self-aligning bearing is arranged on a first transmission system, and a second self-aligning bearing is arranged at the end, far away from the first transmission system, of a second transmission system. The concentricity between a transmission shaft of the first transmission system and the clutch can be automatically adjusted by arranging the first self-aligning bearing in the first transmission system, the end, far away from a clutch type main shaft, of the first transmission system is ensured to be vertically mounted, the concentricity between the second transmission system and the clutch can be automatically adjusted by arranging the second self-aligning bearing in the second transmission system, the position where the second transmission system is connected with the clutch is ensured to be vertically mounted, and therefore the concentricity of thewhole transmission mechanism can be automatically adjusted through one-by-one adaptability of the three parts.

The invention discloses a pulp bleaching device for packaging paper. The device comprises a reaction kettle and a reaction tank. The reaction kettle is installed in the reaction tank; the reaction tank is installed on a base; the reaction kettle is a cylindrical structure, and the outer side of the reaction kettle is surrounded by a heating pipe; a mounting ring plate and a mounting strip plate are arranged in the reaction kettle; the mounting ring plate is provided with a high-pressure nozzle hole; a pushing device is arranged in the reaction tank; and the upper inner side wall of the reaction tank is provided with an air inlet hole, which is communicated with a steam generator through an intake pipe. The device has a high-efficiency bleaching effect. By the device, paper pulp can be fully contacted with a bleaching agent; the bleaching time can be saved and the bleaching process can be simplified; the damage to the fiber structure of paper pulp by multiple operation steps is reduced,and the original quality of paper pulp can be guaranteed; the bleaching efficiency can be improved; equipment investment and floor space are reduced; and the production cost is reduced.

The invention discloses a small hydraulic shock absorber impact test method and device, which are characterized by the following steps: firstly, the hydraulic shock absorber is vertically and fixedly arranged, and its buffer rod is vertically upward; On the line, set the impact load at the set height above the hydraulic buffer; then impact the impact load on the hydraulic buffer in a free fall manner as a drop weight; use a high-speed camera to obtain the amount of the hydraulic buffer during the buffering process. Finally, for the obtained images, the dichotomy method is used to analyze and count the number of pictures taken during the buffering process, and the buffer time of the hydraulic buffer is obtained by dividing the number of pictures by the shooting frame rate of the high-speed camera. The invention further obtains the actuation time of the mechanical system by measuring the buffering time of the small hydraulic buffer, thereby judging the buffering performance of the hydraulic buffer. The method is simple and the test result is accurate.

The invention relates to the technical field of movie and television equipment, in particular to digital media movie and television equipment. The digital media movie and television equipment comprises a frame body and a supporting assembly, wherein the frame body comprises an upper top plate, a side plate and a lower bottom plate, a first connecting shaft is arranged at the top of the side plate,the upper top plate is rotationally connected with the side plate through the first connecting shaft, a second connecting shaft is arranged at the bottom of the side plate, the lower bottom plate isrotationally connected with the side plate through the second connecting shaft, a protruding part is arranged on the lower bottom plate, a mounting cavity is formed in the lower bottom plate, throughgrooves are formed in the bottom of the mounting cavity, supporting legs comprise contact pieces making contact with the ground, rod bodies and connecting pieces, the connecting pieces are provided with rotating pieces, the rotating pieces are clamped into the through grooves and can rotate freely, a first mounting groove and a second mounting groove are formed in the side plate, the upper top plate is clamped into the first mounting groove in a matched mode, and the protruding part on the lower bottom plate is clamped into the second mounting groove in a matched mode. According to the digitalmedia movie and television equipment, the angle is convenient to adjust, meanwhile, mounting is convenient, the overall size is small, and carrying is more convenient.