33results about How to "Control to move left and right" patented technology

The invention discloses an automatic stirring and feeding equipment for pig farms, which comprises a casing, a first sliding chamber is arranged inside the left side of the casing, a first guide groove is arranged on the left inner wall of the first sliding chamber, a first sliding The casing on the right side of the chamber is provided with a second sliding chamber connected with the first sliding chamber, the casing on the right side of the second sliding chamber is provided with a discharge hole extending up and down, and the top of the second sliding chamber is provided with a horizontal through discharge hole. The material hole and the partition guide groove extending to the right, the top of the discharge hole is provided with a funnel-shaped hopper, the top of the funnel-shaped hopper is provided with a feed hopper, the housing above the first sliding chamber is provided with a third sliding chamber, the third The inner walls of the left and right sides of the sliding cavity are symmetrically provided with a third guide groove, and a screw is provided in the first sliding cavity, the bottom of the screw is connected with the power of the first motor, and the upper screw is threaded and connected with a moving block; the present invention is simple in structure, reasonable in design, and easy to operate It is simple, the manufacturing cost is very low and the maintenance cost is low. It is suitable for small and medium-sized farmers. It can automatically control the feeding work and reduce the labor load of workers.

The invention discloses bridge maintenance equipment comprising a material case. A first sliding cavity is formed in the interior of the left side of the material case. A first guiding groove is formed in the inner wall of the left side of the first sliding cavity. A second sliding cavity communicating with the first sliding cavity is formed in the interior, on the right side of the first sliding cavity, of the material case. A discharging groove extending up and down is formed in the interior, on the right side of the second sliding cavity, of the material case. A closing groove penetrating through the discharging groove and extending rightward is formed in the top of the second sliding cavity. A conic cavity is formed in the top of the discharging groove. A feeding cavity is formed in the top of the conic cavity. A third sliding cavity is formed in the interior, on the first sliding cavity, of the material case. Third guiding grooves are formed in the inner walls of the left and right sides of the third sliding cavity symmetrically. A spiral rod is arranged in the first sliding cavity. The bottom of the spiral rod is connected with a first driving machine. A lifting block is connected on the spiral rod in a threaded fit mode. The structure is simple, the design is reasonable, operation is easy, stirring and discharging work can be controlled automatically, the labor amount of workers is reduced, the construction maintenance speed is improved, meanwhile, a lighting function is achieved, the using cost is low, and the existing requirement is met.

The invention discloses a coating device. The coating device comprises a base, a first sliding connection cavity is formed inside the left side of the base, the left inner wall of the first sliding connection cavity is provided with a first guide groove, a second sliding connection cavity communicated with the first sliding connection cavity is formed in the position, on the right side of the first sliding connection cavity, of the base, an output groove extending vertically is formed in the position, on the right side of the second sliding connection cavity, of the base, a closure groove penetrating the output groove and extending rightwards is formed in the top of the second sliding connection cavity, a hopper-shaped portion is arranged at the top of the output groove, a stirring portion is arranged at the top of the hopper-shaped portion, a third sliding connection cavity is arranged in the position, above the first sliding connection cavity, of the base, the left and right inner walls of the third sliding connection cavity are provided with third guide grooves correspondingly, a spiral rod is arranged in the first sliding connection cavity, the bottom of the spiral rod is connected with a first motor, and a push block is connected to an upper thread of the spiral rod. The coating device is simple in structure, reasonable in design, simple to operate, capable of controlling stirring and material discharge automatically and reducing workload of workers, low in use cost, high in stirring uniformity and higher in stirring efficiency and can meet the existing requirements.

The invention discloses a decorative coating device. The decorative coating device comprises a base body, wherein the interior of the left side of the base body is provided with a first sliding connection cavity; the inner wall of the left side of the first sliding connection cavity is provided with a first guide groove; the interior of the base body at the right side of the first sliding connection cavity is provided with a second sliding connection cavity which is communicated with the first sliding connection cavity; the interior of the base body at the right side of the second sliding connection cavity is provided with an output groove which can extend up and down; the top part of the second sliding connection cavity is provided with a sealing groove which penetrates through the output groove and extends to the right side; a hopper-shaped part is arranged at the top part of the output groove, and a uniform stirring part is arranged at the top part of the hopper-shaped part; the interior of the base body above the first sliding connection cavity is provided with a third sliding connection cavity; the inner walls of left side and right side of the third sliding connection cavity are correspondingly provided with third guide grooves; a spiral rod is arranged in the first sliding connection cavity, the bottom part of the spiral rod is connected with a first electric rotation machine, and the spiral rod is in matched connection with a push-up block by threads. The decorative coating device has the advantages that the structure is simple, the design is reasonable, and the operation is simple; the stirring and material discharging are automatically controlled, the labor intensity of workers is decreased, the use cost is lower, the stirring is more uniform, the stirring efficiency is improved, and the existing requirements are met.

The invention discloses novel bridge maintaining equipment. The novel bridge maintaining equipment comprises a material box, a first sliding cavity is formed in the left side of the material box, a first guide groove is formed in the inner wall of the left side of the first sliding cavity, and a second sliding cavity communicating with the first sliding cavity is formed in the portion, located at the right side of the first sliding cavity, of the material box; an arrangement groove arranged in a vertical-extending mode is formed in the portion, located at the right side of the second sliding cavity, of the material box, a closed groove penetrating through the arrangement groove and extending rightwards is formed in the top of the second sliding cavity, a cone-shaped cavity is formed in the top of the arrangement groove, and a feeding cavity is formed in the top of the cone-shaped cavity; and a third sliding cavity is formed in the portion, located above the first sliding cavity, of the material box, third guide grooves are symmetrically formed in the inner walls of the left and right sides of the third sliding cavity, a screw rod is arranged in the first sliding cavity, a first driver is connected with the bottom of the screw rod, and a lifting block is connected to the screw rod in a threaded fit mode. According to the novel bridge maintaining equipment, the structure is simple, the design is reasonable, operation is simple, stirring and discharging work can be automatically controlled, the labor capacity of workers are reduced, the construction and maintenance speed is enhanced, meanwhile the lighting function is achieved, the use cost is low, and current requirements are met.

A processing device is disclosed. The device includes a machine body. The inside of the left side of the machine body is provided with a first sliding cavity. The left side inner wall of the first sliding cavity is provided with a first guiding and conveying slot. A second sliding cavity communicated with the first sliding cavity is disposed in the machine body at the right side of the first sliding cavity. A discharging passage extending up and down is disposed in the machine body at the right side of the second sliding cavity. The top of the second sliding cavity is provided with a separating slot penetrating the discharging passage and extending to the right side. The top of the discharging passage is provided with a hopper. The top of the hopper is provided with a stirring part. A third sliding cavity is disposed in the machine body above the first sliding cavity. Left and right inner walls of the third sliding cavity are provided with third guiding and conveying slots symmetrically. A stud is disposed in the first sliding cavity. The bottom of the stud is connected to a first motor. The stud is in threaded connection with a touching and pressing block. The device is simple in structure, reasonable in design, simple to operate and capable of automatically controlling stirring and material discharging, has a reminding function, and is capable of reducing labor of workers, increasing the working efficiency, making stirring effects good and making food safety high.

The invention discloses a coating matching device which comprises a matrix. A first slide cavity is arranged inside the left side of the matrix, a first guide groove is formed in the inner wall of the left side of the first slide cavity, a second slide cavity which is communicated with the first slide cavity is arranged in the matrix and is positioned on the right side of the first slide cavity, an output groove is formed in the matrix in an extension manner in the up-down direction and is particularly formed in the right side of the second slide cavity, an enclosed groove which is perforated through the output groove and extends towards the right side is formed in the top of the second slide cavity, a hopper-shaped portion is arranged on the top of the output groove, a stirring portion is arranged on the top of the hopper-shaped portion, a third slide cavity is arranged in the matrix and is positioned above the first slide cavity, third guide grooves are correspondingly formed in the inner walls of the left side and the right side of the third slide cavity, a spiral rod is arranged in the first slide cavity, a first electric rotary machine is connected with the bottom of the spiral rod, and a pushing and lifting block is fittingly connected onto the spiral rod in a threaded manner. The coating matching device has the advantages that the coating matching device is simple in structure, reasonable in design and easy to operate, stirring and discharging work can be automatically controlled, and accordingly the amount of labor can be reduced for workers; the coating matching device is low in service cost, uniform stirring effects can be realized, the stirring efficiency can be improved, and existing requirements can be met.

The invention discloses an automatic stirring and feeding equipment for pig farms, which comprises a casing, a first sliding chamber is arranged inside the left side of the casing, a first guide groove is arranged on the left inner wall of the first sliding chamber, and the first sliding chamber The housing on the right side is provided with a second sliding chamber connected with the first sliding chamber, the housing on the right side of the second sliding chamber is provided with a discharge hole extending up and down, and the top of the second sliding chamber is provided with a horizontal through discharge hole. hole and the partition guide groove extending to the right, a funnel-shaped hopper is provided on the top of the discharge hole, a feed hopper is provided on the top of the funnel-shaped hopper, a third sliding chamber is provided in the housing above the first sliding chamber, and the third sliding chamber The inner walls of the left and right sides of the cavity are symmetrically provided with a third guide groove, and a screw is provided in the first sliding cavity, the bottom of the screw is connected with the power of the first motor, and the upper screw is threaded and connected with a moving block; the invention has simple structure, reasonable design and simple operation , The manufacturing cost is very low and the maintenance cost is low. It is suitable for small and medium-sized farmers. It can automatically control the feeding work and reduce the labor load of workers.

The invention discloses automatic stirring and feeding equipment for pig raising. The equipment includes a housing, the left side of the housing is internally provided with a first sliding cavity, the inner wall of the left side of the first sliding cavity is provided with a first guide groove, the portion, on the right side of the first sliding cavity, of the housing is internally provided with a second sliding cavity communicated with the first sliding cavity, the portion, on the right side of the second sliding cavity, of the housing is internally provided with a discharge hole extending up and down, the top of the second sliding cavity is provided with a partition plate guide groove which transversely penetrates through the discharge hole and extends to the right side, the top of the discharge hole is provided with a funnel-shaped hopper, the top of the funnel-shaped hopper is provided with a feeding hopper, the portion, above the first sliding cavity, of the housing is internally provided with a third sliding cavity, the inner walls of the left side and the right side of the third sliding cavity are symmetrically provided with third guide grooves, a threaded rod is arranged in the first sliding cavity, the bottom of the threaded rod is in powered connection with a first motor, and the threaded rod is connected with a moving block in a screw-thread fit mode. According to the equipment, the structure is simple, the design is reasonable, the operation is simple, the manufacturing cost and the maintenance cost are very low, the equipment is suitable for small and medium-sized farmers to use, feeding work can be automatically controlled and the labor amount of workers is reduced.

The invention discloses an agricultural machine for fertilization, which comprises a box body, a first sliding chamber is arranged inside the left side of the box body, a first guide groove is arranged on the inner wall of the left side of the first sliding chamber, and a The box body of the second slip chamber is provided with a second slip chamber connected with the first slip chamber, the box body on the right side of the second slip chamber is provided with a discharge groove extending up and down, and the top of the second slip chamber is provided with The switch slot that penetrates the delivery slot and extends to the right side, the top of the delivery slot is provided with a bucket, the top of the bucket is provided with a feeding section, and the box above the first slide chamber is provided with a third slide cavity, the inner walls of the left and right sides of the third sliding cavity are correspondingly provided with a third guide groove, the first sliding cavity is provided with a screw rod, the bottom of the screw rod is connected with the first motor, and the screw thread on the screw rod matches Connected with a top block; the invention has simple structure, reasonable design, simple operation, low manufacturing and maintenance costs, suitable for individual growers, can automatically control the stirring and discharging work, the stirring is relatively uniform, the labor load of workers is reduced, and the fertilization efficiency is improved.

The invention discloses a jigging and flotation integrated coal wash-dressing machine. The jigging and flotation integrated coal wash-dressing machine comprises a machine body, wherein a screening cavity is arranged in the machine body, two nozzles which are symmetrical left and right and can spray water into the screening cavity are fixedly arranged on the top wall of the screening cavity, a screening net which can screen coal is arranged in the screening cavity, a screening mechanism which achieves the effect of jigging and screening of coal through the water sprayed out by the nozzles and vibration of the screening net is arranged in the screening cavity, and the lower side of the screening cavity communicates with a working cavity. According to the jigging and flotation integrated coalwash-dressing machine, the two modes of jigging screening and bubble flotation are combined together to wash coal powder and separate out clean coal, the washing effect of the coal is effectively improved, the quality of the coal is effectively improved, and the problem of qualified washing caused by faults or errors generated in a single washing process is reduced.

The invention discloses a convenient processing apparatus, comprising an apparatus body, wherein the interior of the left side of the apparatus body is provided with a first sliding chamber; the left inner wall of the first sliding chamber is provided with a first guiding and conveying groove; a second sliding chamber communicated with the first sliding chamber is arranged in the part, located at the right side of the first sliding chamber, of the apparatus body; a discharging channel arranged to extend upwardly and downwardly is mounted in the part, located at the right side of the second sliding chamber, of the apparatus body; the top of the second sliding chamber is provided with a separating groove communicated with the discharging channel and extending rightward; the top of the discharging channel is provided with a hopper; the top of the hopper is provided with a stirring part; a third sliding chamber is arranged in the part, located above the first sliding chamber, of the apparatus body; the inner walls of the left and right sides of the third sliding chamber are correspondingly provided with third guiding and conveying grooves; a bolt is arranged in the first sliding chamber; the bottom of the bolt is connected with a first motor; and the bolt is in screw-thread fit with a touch press block. The convenient processing apparatus provided by the invention is simple in structure, reasonable in design, simple to operate and capable of automatically controlling stirring and discharging operations; and the convenient processing apparatus has a prompting function, can reduce the amount of labor work, is good in stirring effect, enables food safety to be high and improves work efficiency.

The invention discloses a rostrum for teachers in junior high schools. The rostrum includes a rostrum body, a retractable plate is arranged in an inner cavity of the rostrum body, the right side of the retractable plate penetrates through the rostrum body and extends to the outer side of the rostrum body, a supporting leg is fixedly connected to the right side of the bottom of the retractable plate, a first bracket is fixedly connected to the bottom of the supporting leg, and a first roller is movably connected to the bottom of the first bracket. Through arrangement and cooperation of the rostrum body, the retractable plate, the supporting leg, the first bracket, the first roller, a second bracket, a second roller, a sliding groove, a threaded sleeve, a threaded rod, a first rotating rod,a first gear, a second gear, a second rotating rod, a connecting rod, a handle, a first connecting block, a second connecting block, a movable plate, a fixing block and a fixing rod for use, the problem that the use areas of existing rostrums in classrooms cannot be increased is solved, and the rostrum for teachers has the advantages of an increasable use area and is worthy of popularization.

The invention relates to a compactor, in particular to a high-efficiency compactor for waste cotton pads for the medical gynecology. The high-efficiency compactor for the waste cotton pads for the medical gynecology has the advantage that compacting is rapid. The high-efficiency compactor for the waste cotton pad for the medical gynecology comprises a first mounting plate, a second mounting plate,a driving mechanism, a first moving mechanism, a fixing mechanism, a second moving mechanism, a height adjusting mechanism, a third mounting plate, a first fixing rod, a first sliding block, a flat belt, a first sliding rail, a circular pipe, a sliding rod, a second sliding block, a second fixing rod, a rolling wheel, a second sliding rail and a placement box, wherein the second mounting plate isfixedly connected to the end part of the first mounting plate in the vertical direction, and the third mounting plate is fixedly connected to the top of the second mounting plate in the horizontal direction. According to the high-efficiency compactor, the effect of rapid compaction can be achieved.

The invention discloses a fertilizing device for agricultural planting, which comprises a box body, a first sliding chamber is arranged inside the left side of the box body, a first guide groove is arranged on the left inner wall of the first sliding chamber, and a first sliding chamber The box on the right side is provided with a second slip chamber communicating with the first slip chamber, and the box on the right side of the second slip chamber is provided with a discharge groove extending up and down, and the top of the second slip chamber There is a switch slot that penetrates the discharge slot and extends to the right. The top of the discharge slot is provided with a bucket, the top of the bucket is provided with a feeding section, and the box above the first slide chamber is provided with a third Sliding cavity, the inner walls of the left and right sides of the third sliding cavity are correspondingly provided with a third guide groove, the first sliding cavity is provided with a screw rod, the bottom of the screw rod is connected with the first motor, and the screw rod is The top block is connected with the pattern; the invention has simple structure, reasonable design, simple operation, low manufacturing and maintenance costs, suitable for individual growers, can automatically control the stirring and discharging work, the stirring is relatively uniform, the labor load of workers is reduced, and the fertilization efficiency is improved. .

The invention discloses a high-efficiency processing device, which comprises a machine body. A first slide chamber is arranged inside the left side of the machine body. A first guide groove is provided on the inner wall of the left side of the first slide chamber. The second sliding chamber is connected with the first sliding chamber. The body on the right side of the second sliding chamber is provided with a discharge channel extending up and down. The top of the second sliding chamber is provided with a separation groove extending to the right through the discharge channel. There is a hopper on the top of the channel, and a stirring part is arranged on the top of the hopper. A third sliding chamber is provided in the body above the first sliding chamber. The inner walls on the left and right sides of the third sliding chamber are equally provided with third guide grooves. The first There is a stud in the sliding chamber, the bottom of the stud is connected with the first motor, and the screw is connected with a contact pressure block; the invention has simple structure, reasonable design, simple operation, can automatically control the stirring and discharging work, and has Reminder function, reduce the labor load of workers, good mixing effect, high food safety, and improve work efficiency.

The invention discloses a puncture locator for spine surgery, and relates to the technical field of medical apparatus and instruments. The puncture locator for the spine surgery comprises a fixing sleeve, wherein one end of the inner cavity of the fixing sleeve is provided with a first rotation groove; a first rotation shaft is arranged in the first rotation groove; two ends of the outer side of the first rotation shaft are independently provided with a first bevel gear; one end of the fixing sleeve is provided with a first through hole; one end, which is near the first through hole, of the fixing sleeve is provided with a motor; the first rotation shaft is fixedly connected with the output shaft of the motor through the first through hole; two ends of the top of the fixing sleeve are independently provided with a second through hole; a first threaded rod is arranged in each second through hole; and the bottom of each first threaded rod is provided with a second bevel gear. By use of the puncture locator for the spine surgery, the problem that a slight deviation of a needle inserting position causes an inestimable result can be effectively solved, and the problems that most existing locators only can regulate the angle of a puncture needle through a computer and each angle of the whole can not be accurately regulated can be solved.

The invention discloses bridge deck maintaining equipment comprising a material box. A first sliding cavity is formed in the left side of the material box, and a first guide groove is formed in the inner wall of the left side of the first sliding cavity; a second sliding cavity communicated with the first sliding cavity is formed in the portion, located on the right side of the first sliding cavity, of the material box, and a discharging groove which is arranged in a vertical-extending mode is formed in the portion, located on the right side of the second sliding cavity, of the material box; aclosed groove which penetrates through the discharging groove and extends to the right side is formed in the top of the second sliding cavity, a conical cavity is formed in the top of the discharginggroove, and a feeding cavity is formed in the top of the conical cavity; a third sliding cavity is formed in the portion, located above the first sliding cavity, of the material box, and third guidegrooves are symmetrically formed in the inner walls of the left side and the right side of the third sliding cavity; a spiral rod is arranged in the first sliding cavity, and the bottom of the spiralrod is connected with a first driving machine; and spiral lines on the spiral rod are connected with a lifting block in a matched mode. The bridge deck maintaining equipment is simple in structure, reasonable in design, easy to operate, and capable of automatically controlling stirring and discharging, so that the labor amount of workers is reduced, the construction and maintaining speed is increased, an illumination function is achieved, the use cost is low, and the existing requirements are met.

The invention discloses a practical water-saving irrigation device. The device includes a main machine body composed of a first machine body and a second machine body, the second machine body is positioned at the top of the right side of the first machine body, a water tank is arranged at the top of the left side of the first machine body, an irrigation device body is rotabtaly and cooperatively connected with a marginal portion of the top of the right side of the second machine body, a stirring device is rotatably and cooperatively connected in the water tank, a first containing cavity is formed in the first machine body below the bottom of the water tank, a first rotary rod extending upwards and downwards is rotatably and cooperatively connected in the inner top surface of the first containing cavity, an extending part of the top of the first rotary rod penetrates through the bottom of the water tank and is fixedly connected with the stirring device, the extending part of the bottomof the first rotary rod extends into the first containing cavity and is fixedly provided with a first conical wheel at the tail end, and the first machine body below the second machine body is internally provided with a second containing cavity in the right side of the first containing cavity. The practical water-saving irrigation device has the advantages that the structure is simple, the operation is convenient, the time and labor are saved, the jetting orientation is convenient to adjust, the operation stability is high, and the water supply range is wide.

The invention discloses cooling equipment which comprises a vehicle platform composed of a first base platform and a second base platform. The second base platform is located on the top of the right side of the first base platform; a storage box is arranged on the top of the left side of the first base platform; a water spraying device is connected on the top of the right side of the second base platform in a switch-over mode; a stirring device is connected in the storage box in a switch-over mode; a first inner cavity is formed in the position, on the lower portion of the bottom of the storage box, of the first base platform; a first switch-over connecting shaft extending up and down is connected inside the top surface inside the first inner cavity in a switch-over mode; the top extending section of the first switch-over connecting shaft penetrates through the bottom of the storage box and is fixedly connected with the stirring device; the bottom extending section of the first switch-over connecting shaft extends into the first inner cavity, and the tail end of the bottom extending section of the first switch-over connecting shaft is fixedly provided with a first cone pulley; and a second inner cavity which is formed in the right side of the first inner cavity is formed in the position, on the lower portion of the second base platform, of the first base platform. The cooling equipment is simple in structure and convenient to operate, the time and labor are saved, the spraying direction is easy to adjust, operation stability is high, and the water spraying range is wide.

The invention discloses an automobile seat force measurement experiment platform, which comprises a base. The outer surface of the top portion of the base is fixedly connected with a support base; andone side of the support base is movably connected with a lead screw shaft. The lead screw shaft is concentrically and externally movably connected with a nut base. The outer surface of the top portion of the nut base is fixedly connected with an experiment platform. The experiment platform is internally provided with screws. The experiment platform and the nut base are fixedly connected through the screws. One tail end of the lead screw shaft is connected with a shaft coupler. One tail end of the shaft coupler is provided with a servo motor. The servo motor is concentrically sleeved by a rotation shaft. The shaft coupler is fixedly connected with the servo motor through the rotation shaft. The experiment platform is internally provided with a connection hole. The connection hole is fixedly connected with a support in the same central axis. A mechanism, which can move up and down and left and right is provided, and the angle of the connecting rod can be adjusted, so that measurement offorce and data in different areas of an automobile seat can be achieved conveniently.

The invention provides an auxiliary positioning device for convenient wall reinforcing bar punching for building construction, and belongs to the field of building construction. The auxiliary positioning device comprises a supporting main rod part, wherein two slide paths which are symmetrically arranged up and down are arranged on the middle part of the supporting main rod part; four roller wheels are symmetrically arranged in the two slide ways left and right; square movable slide plates are horizontally and fixedly connected in the middle of the four roller wheels; a first slide slot is horizontally formed in the middle of each movable slide plate; and two vertical slide blocks are perpendicularly in sleeve connection in each first slide sloth symmetrically left and right. According tothe auxiliary positioning device provided by the invention, the four roller wheels conveniently slide left and right in the two slide paths, the movable slide plates conveniently slide left and rightin the two slide paths through the four roller wheels, and the two vertical slide blocks conveniently move left and right in each first slide slot; when a rotary threaded rod rotates upwards for conveniently driving the two vertical slide blocks to get close to the middle; when the rotary threaded rod rotates downwards for driving the two vertical slide blocks to separate towards left and right ends; and a rotary handle is convenient for rotating the rotary threaded rod by a user.

The invention provides an auxiliary positioning device for convenient wall reinforcing bar punching for building construction, and belongs to the field of building construction. The auxiliary positioning device comprises a supporting main rod part, wherein two slide paths which are symmetrically arranged up and down are arranged on the middle part of the supporting main rod part; four roller wheels are symmetrically arranged in the two slide ways left and right; square movable slide plates are horizontally and fixedly connected in the middle of the four roller wheels; a first slide slot is horizontally formed in the middle of each movable slide plate; and two vertical slide blocks are perpendicularly in sleeve connection in each first slide sloth symmetrically left and right. According tothe auxiliary positioning device provided by the invention, the four roller wheels conveniently slide left and right in the two slide paths, the movable slide plates conveniently slide left and rightin the two slide paths through the four roller wheels, and the two vertical slide blocks conveniently move left and right in each first slide slot; when a rotary threaded rod rotates upwards for conveniently driving the two vertical slide blocks to get close to the middle; when the rotary threaded rod rotates downwards for driving the two vertical slide blocks to separate towards left and right ends; and a rotary handle is convenient for rotating the rotary threaded rod by a user.