A middle lifting cylinder of a lifting mast of a forklift truck and the lifting mast

Abstract

This invention discloses an intermediate lifting cylinder and a lifting mast for a forklift, belonging to the field of forklift technology. The application includes a base, a cylinder body, and a drive sprocket assembly. The drive sprocket assembly includes a drive wheel that lifts and lowers synchronously with the telescopic shaft and a transmission chain sleeved on the drive wheel. A dust blowing assembly includes a guide cylinder mounted on the base and a guide rod disposed within the guide cylinder. The upper end of the guide rod is connected to the upper end of the telescopic shaft via a mounting plate. The drive sprocket assembly is positioned above the mounting plate. The guide rod has equidistant exhaust holes facing the telescopic shaft. The guide rod is hollow and has a baffle rod inside. This invention enables dust removal and cleaning of the telescopic shaft, allowing the air drawn into the guide cylinder by the telescopic shaft to be accurately and directionally ejected. This increases the pressure generated when the gas is ejected, thereby improving the cleaning force, and also prevents the ejected gas from diffusing, ensuring stable cleaning results.

Description

Technical Field

[0001] This invention relates to an intermediate lifting cylinder and a lifting mast for a forklift, belonging to the field of forklift technology. Background Technology

[0002] The forklift mast is the main load-bearing structure of the forklift unit. As a mechanism for lifting goods, it is also called the mast. It consists of an inner mast, an outer mast, a fork carriage, forks, sprockets, chains, lifting cylinders, and intermediate cylinders. In the forklift mast system, the intermediate cylinder includes a cylinder barrel and a piston rod that are nested together. The cylinder barrel is fixed to the outer mast, and the upper end of the piston rod is fixed to the sprocket mechanism.

[0003] During forklift operation, factors such as cargo handling often result in a large amount of dust and other particulate matter floating around. The lifting cylinder itself is in this environment during lifting and lowering, and is easily contaminated with a lot of dust. This dust is then carried into the cylinder during the return stroke, thus affecting the service life of the entire lifting cylinder. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an intermediate lifting cylinder and a lifting mast for a forklift, which solves the problem in the prior art that the intermediate lifting cylinder of the forklift is prone to dust accumulation, affecting its service life.

[0005] The technical problem to be solved by the present invention is achieved by the following technical solution: an intermediate lifting cylinder for a forklift lifting mast, including a base, which is fixedly installed on the lifting mast of the forklift; The cylinder body includes a cylinder barrel disposed on the base and a telescopic shaft disposed within the cylinder barrel; The drive sprocket assembly includes a drive wheel that moves up and down synchronously with the telescopic shaft and a transmission chain sleeved on the drive wheel; The dust blowing assembly includes a guide cylinder disposed on the base and a guide rod disposed inside the guide cylinder. The upper end of the guide rod is connected to the upper end of the telescopic shaft and a mounting plate is provided. The drive sprocket assembly is disposed above the mounting plate. The guide rod has vent holes equidistantly arranged in the direction of the telescopic shaft. The guide rod is hollow inside and has a blocking rod for blocking the vent holes. The blocking rod is used to control the number of vent holes that are open.

[0006] By adopting the above technical solution, the number of exhaust holes opened is controlled by relative sliding, achieving dynamic matching between the blowing range and the telescopic height. This allows the air drawn into the guide cylinder by the telescopic shaft to be accurately and directionally ejected. This not only increases the pressure generated when the gas is ejected, thereby improving the cleaning force, but also prevents the ejected gas from spreading, ensuring stable cleaning results. Each ejected gas is directed close to a point near the inner cavity of the dry cylinder, allowing the telescopic shaft in that section to immediately retract into the cylinder after the airflow cleans the dust, preventing secondary dust contamination. Furthermore, because the airflow point is always maintained at the upper inlet position of the cylinder, the amount of floating dust in that area is significantly reduced.

[0007] The present invention is further configured such that: an air inlet is provided at the lower end of the guide cylinder connected to the base, and a first plug is provided at the air inlet; an air outlet is provided at the upper end of the barrier rod, and a second plug is provided at the air outlet.

[0008] By adopting the above technical solution, a spherical plug is used, which has a line contact seal with the corresponding air inlet and outlet, resulting in low movement resistance and rapid opening and closing when the air pressure changes, ensuring that the dust blowing action is synchronized with the lifting and lowering of the hydraulic cylinder.

[0009] The invention is further configured such that: a buffer cavity is provided between one end of the barrier rod, which is hollow inside and slidably disposed inside the guide cylinder, and the lower end of the guide rod, and an adjusting spring is provided inside the buffer cavity.

[0010] By adopting the above technical solution, and through the coordinated design of the buffer chamber and the adjusting spring, the air extraction speed inside the guide cylinder can be kept relatively smooth, preventing drastic changes in internal pressure caused by rapid up-and-down movement of the entire telescopic shaft. When the acceleration generated during the upward or downward movement of the telescopic shaft is relatively fast, the adjusting spring in the buffer chamber will be stretched or compressed, thereby generating a certain pulling or pushing force on the blocking rod, which plays a buffering role, making the entire air extraction process relatively smooth. After the telescopic shaft stabilizes, the compressed elastic potential energy or the reverse elastic potential energy generated by the stretching is gradually released. Finally, under the condition of smooth air extraction or exhaust, the air pressure change in the inner cavity of the guide cylinder is controlled, achieving smooth air extraction and exhaust, and ensuring a stable and sufficient airflow ejected from the telescopic shaft.

[0011] The present invention is further configured such that: the upper and lower ends of the adjusting spring are respectively fixedly connected to the guide rod and the end of the blocking rod, and the buffer cavity is connected to the inner cavity of the guide cylinder.

[0012] By adopting the above technical solution, the space inside the entire guide cylinder can be fully utilized to maximize the gas storage capacity, thereby providing a stable gas source for the subsequent dust removal of the telescopic shaft.

[0013] The present invention is further configured such that: the number of exhaust holes is at least five, and they are equidistantly opened on the guide rod along the axial direction of the guide rod.

[0014] By adopting the above technical solution and setting multiple exhaust ports, the more exhaust ports there are, the higher the directional accuracy during exhaust, and the smaller the fluctuation in the position of the airflow blowing towards the telescopic shaft after exhaust. Exhaust ports at different heights ensure that the guide cylinder maintains a relatively stable height during exhaust, ensuring that the exhaust gas is always located near the cylinder inlet.

[0015] The present invention is further configured such that: the number of guide cylinders is at least two, which are disposed on the base of the outer ring of the cylinder, and a reinforcing plate is disposed between the upper end of the guide cylinder and the cylinder.

[0016] By adopting the above technical solution and using two opposing guide cylinders in combination, the exhaust airflow can generate convection, thereby improving the dust removal rate. This causes the airflow near the telescopic shaft to be disturbed outward, and the dust in the air can be carried away with the disturbed airflow, preventing it from adhering to the telescopic shaft.

[0017] The present invention is further configured such that: a sealing ring is sleeved on the end of the guide rod slidably disposed in the inner cavity of the guide cylinder, and sealing rings are sleeved on both the upper and lower ends of the barrier rod.

[0018] By adopting the above technical solution, leakage channels can be effectively sealed, the airtightness of each chamber can be ensured, and compressed air can be ejected from the exhaust port at sufficient pressure, thereby improving the dust blowing speed and effect.

[0019] The present invention is further configured such that: a sealing plug is connected to the second plug, and a thrust spring is provided between the upper end of the sealing plug and the upper surface of the inner cavity of the guide rod; the thrust force applied by the thrust spring to the second plug is always less than the pressure generated when the air in the bottom cavity of the guide cylinder is compressed when the guide rod slides down.

[0020] By adopting the above technical solution, the pressure generated by the compressed air in the guide rod will only overcome the spring thrust and push open the plug to blow away dust when the oil cylinder descends (returns). When the oil cylinder rises, the negative pressure and spring force can make the plug close tightly, avoiding ineffective dust blowing.

[0021] The present invention is further configured such that: the bottom of the base has a cavity communicating with the inner cavity of the guide cylinder, and a filter plate for filtering air is provided in the cavity at the bottom of the base.

[0022] By adopting the above technical solution, the filter plate effectively filters out dust and sand particles in the air, ensuring that the air blown toward the telescopic shaft is clean and preventing secondary wear.

[0023] This application also relates to a forklift lifting mast, wherein an intermediate lifting cylinder is installed on the forklift lifting mast for driving itself to rise or fall.

[0024] By adopting the above technical solution, the serious wear problem caused by dust entering the intermediate lifting cylinder of the traditional lifting gantry can be effectively avoided, and the reliability and durability of the entire gantry system can be greatly improved.

[0025] The beneficial effects of this invention are: By actively cleaning the telescopic shaft in real time, the directional airflow continuously sweeps the surface of the telescopic shaft, eliminating the problem of dust carrying back during the return trip from the source. This can reduce the wear rate of the cylinder seals and cylinder walls by more than 70%, extending the overall service life of the cylinder by 2-3 times and effectively reducing the subsequent maintenance costs of the forklift lifting mast.

[0026] By setting multiple exhaust holes for switching exhaust, the airflow direction discharged from the guide cylinder can be kept stable with a small range of vertical height fluctuation, thereby achieving point-to-point and directional cleaning of the telescopic shaft. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a front view of the present invention; Figure 3 This is an internal cross-sectional view of the dust blowing assembly of the present invention; Figure 4 This is a three-dimensional structural diagram of the present invention; Figure 5 This is a three-dimensional structural diagram of another embodiment of the present invention.

[0028] In the diagram: 1. Base; 2. Cylinder body; 201. Cylinder barrel; 202. Telescopic shaft; 3. Drive sprocket assembly; 301. Drive wheel; 302. Transmission chain; 4. Dust blowing assembly; 401. Guide cylinder; 402. Guide rod; 403. Exhaust port; 404. Barrier rod; 405. Air inlet; 406. Plug one; 407. Plug two; 408. Buffer chamber; 409. Adjusting spring; 410. Sealing plug; 411. Thrust spring; 412. Piston disc; 413. Connecting hole; 5. Mounting plate; 6. Reinforcing plate; 7. Filter plate; 8. Lifting forks; 9. Forklift; 10. Push cylinder; 11. Fixed guide bracket; 12. Sliding guide bracket. Detailed Implementation

[0029] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific illustrations.

[0030] like Figure 1 As shown, a middle lifting cylinder for a forklift mast includes a base 1 fixedly mounted on the lifting mast, a cylinder body 2 fixed on the base 1, and at least two dust blowing components 4 equidistantly mounted on the outer circumference of the cylinder body 2. The cylinder body 2 includes a cylinder barrel 201 fixed on the base 1 and a telescopic shaft 202 slidably disposed within the cylinder barrel 201 and capable of vertical extension and retraction. A sealing piston is provided at the end of the telescopic shaft 202 slidably disposed within the cylinder barrel 201, and a drive sprocket assembly 3 is connected to the upper end outside the cylinder barrel 201. The drive sprocket assembly 3 includes a drive wheel 301 rotatably mounted on the upper end of the telescopic shaft 202 and a transmission chain 302 disposed through the drive wheel 301. The two ends of the transmission chain 302 are respectively connected to the base 1 and the lifting frame in the lifting mast.

[0031] The drive sprocket assembly 3 includes a drive wheel 301 that rises and falls synchronously with the telescopic shaft 202, and a transmission chain 302 sleeved on the drive wheel 301. One end of the transmission chain 302 is fixed to the base 1, and the other end is connected to the lifting forks 8 of the external lifting gantry. The drive wheel 301 is driven to rise by the telescopic shaft 202, thereby causing the drive wheel 301 to rotate relative to the transmission chain 302, gradually lifting the lifting forks 8 upward, thus achieving the lifting of the goods.

[0032] It should be noted that in the above embodiments, the lifting mast is a double-rail lifting type, meaning that two sets of guide supports are installed on the lifting mast. The first set of guide supports is lifted relative to the second set of guide supports by a central lifting cylinder, while the second set of guide supports is lifted relative to the entire forklift 9 by a drive component mounted on the forklift 9. In other embodiments, the lifting cylinder described in this application can also be applied to a single-rail lifting mast, where the telescopic shaft 202 pushes the entire lifting mast directly relative to the forklift 9 body.

[0033] like Figure 2 and Figure 3 As shown, the dust blowing assembly 4 includes a guide cylinder 401 mounted on a base 1 and a guide rod 402 disposed within the guide cylinder 401. The upper end of the guide rod 402 is connected to the upper end of the telescopic shaft 202 via a mounting plate 5. The drive sprocket assembly 3 is disposed above the mounting plate 5. The guide rod 402 has equidistant exhaust holes 403 facing the telescopic shaft 202. The guide rod 402 is hollow and has a blocking rod 404 for blocking the exhaust holes 403. The blocking rod 404 controls the number of exhaust holes 403 that are open.

[0034] In the above embodiment, the injection direction of all exhaust holes 403 is towards the inner cavity inlet edge at the upper end of the cylinder 201, and forms a preset angle of 30°~45° with the outer surface of the telescopic shaft 202, with the exhaust direction of the exhaust holes 403 pointing upwards. During the telescopic movement of the telescopic shaft 202, the blocking rod 404 slides relative to the guide cylinder 401. Through this relative sliding, the exhaust holes 403 on the side wall of the guide rod 402 are blocked or exposed in turn, thereby accurately controlling the actual opening position of the exhaust holes 403, so that the effective blowing range corresponds to the real-time telescopic height of the telescopic shaft 202. Specifically, when the telescopic shaft 202 extends outward from inside the cylinder 201, the guide rod 402 moves upward synchronously with the telescopic shaft 202, causing the exhaust port 403 to be exposed. The number of open exhaust ports 403 increases linearly with the increase of the extension height, and the airflow coverage area expands synchronously. When the telescopic shaft 202 retracts into the cylinder 201, the guide rod 402 moves downward synchronously with the telescopic shaft 202. The upper end face of the cylinder 201 gradually blocks the exhaust ports 403 above. The number of open exhaust ports 403 decreases linearly with the decrease of the retraction height, and the airflow coverage area shrinks synchronously.

[0035] The number of exhaust holes 403 is at least five, and they are equidistantly opened on the side wall of the guide rod 402 along the axial direction of the guide rod 402. In this embodiment, the number of exhaust holes 403 is fifteen, and they are equidistantly arranged along the axial direction of the guide rod 402.

[0036] Because the number of open exhaust ports 403 corresponds to the telescopic height, the airflow can always be focused on the currently exposed shaft section surface of the telescopic shaft 202. This effectively gathers airflow energy, increases the instantaneous pressure of the ejected gas, and enhances the blowing force on the dust adhering to the shaft surface. It also prevents the airflow from spreading disorderly in all directions, ensuring consistent cleaning results across different telescopic strokes. Specifically, in this embodiment, the airflow injection point of all open exhaust ports 403 is always concentrated near the inner cavity inlet at the upper end of the cylinder 201. When the telescopic shaft 202 completes its retraction, the airflow immediately blows away the dust adhering to the surface of the telescopic shaft 202 section outside the cylinder 201, preventing it from being carried into the cylinder 201. Simultaneously, the continuously directional airflow forms a localized air curtain in the upper inlet area of ​​the dry cylinder 201, continuously blowing away suspended dust in that area, significantly reducing the probability of the telescopic shaft 202 becoming dusty during its entry and exit from the cylinder 201.

[0037] Furthermore, such as Figure 3As shown, a conical air inlet 405 is provided at the lower end of the guide cylinder 401 connected to the base 1. A plug 406 is provided at the air inlet 405. When the guide rod 402 rises synchronously with the telescopic shaft 202, the air inlet 405 draws air outward, and the external airflow can push open the plug 406 and enter the inner cavity of the guide cylinder 401. Conversely, when the guide rod 402 descends synchronously with the telescopic shaft 202, the gas in the guide cylinder 401 is pressurized and presses the plug 406 against the air inlet 405, sealing the air inlet 405. This allows the gas in the guide cylinder 401 to flow upward along the inner cavity of the guide rod 402. In addition, a plug 407 is also provided at the upper air outlet of the blocking rod 404. The air outlet also has a conical cross-section, and its opening and closing timing is opposite to that of the air inlet 405 located below the guide cylinder 401. That is, when the air inlet 405 is open, the air outlet is closed, and when the air inlet 405 is closed, the air outlet is open.

[0038] In the above embodiments, the shape of plug 406 and plug 407 can be a conical or spherical structure adapted to the cross-section of the corresponding air inlet 405 and air outlet, and the material can be made of elastic material, so that when the air inlet 405 or air outlet is blocked in the future, it can undergo partial deformation and fit more tightly with it.

[0039] By using the aforementioned one-way air inlet 405 and air outlet, the gas inside the guide cylinder 401 can quickly switch between inlet and outlet states as the guide rod 402 moves up and down, ensuring the stability of dust blowing. Furthermore, by employing conical air inlets 405 and air outlets, along with matching conical or spherical plugs, the internal cavity of the guide cylinder 401 can quickly open and close in response to pressure changes.

[0040] Furthermore, the baffle rod 404 is hollow inside, and its lower end is slidably disposed inside the guide cylinder 401, with a buffer cavity 408 reserved between the lower end of the guide rod 402 and the lower end of the baffle rod 402. An adjusting spring 409 is installed in the buffer cavity 408. The upper and lower ends of the adjusting spring 409 are fixedly connected to the guide rod 402 and the guide cylinder 401, respectively. During the process of the guide rod 402 moving up and down along the axis of the guide cylinder 401, the adjusting spring 409 can generate corresponding stretching or compression, thereby achieving buffering of air extraction or exhaust, so that the air pressure change inside the guide cylinder 401 maintains a relatively stable linear fluctuation. This can effectively avoid large local stress fluctuations when the telescopic rod switches between rising and falling states, which would cause large air pressure fluctuations in the cavity of the guide cylinder 401 and affect subsequent exhaust and dust removal.

[0041] Specifically, the barrier rod 404 is coaxially slidably inserted into the inner cavity of the guide cylinder 401. Its lower end is fixedly connected to a piston disc 412 that is in sealing and sliding fit with the inner wall of the guide cylinder 401. The piston disc 412 divides the upper part of the inner cavity of the guide cylinder 401 into a buffer cavity 408. Its upper end extends out of the buffer cavity 408 and into the inner cavity of the guide rod 402. The adjusting spring 409 is sleeved on the outside of the rod section of the barrier rod 404 located in the buffer cavity 408. Its upper end is fixed to the lower end of the guide rod 402, and its lower end is fixed to the upper surface of the piston disc 412. When the airflow suction assembly draws or vents air from the internal cavity of the guide cylinder 401 through the internal air passage of the telescopic shaft 202, if the telescopic shaft 202 experiences rapid lifting or lowering due to changes in operating conditions, the resulting instantaneous acceleration will cause the guide rod 402 to jerk or momentarily displace relative to the guide cylinder 401. By setting an adjusting spring 409, the blocking rod 404 connected to the guide rod 402 can be buffered, thus preventing excessive local suction or venting pressure. This allows the blocking rod 404 to undergo a relatively smooth axial displacement relative to the buffer cavity 408 along with the guide cylinder 401.

[0042] When the telescopic shaft 202 rises rapidly, the guide cylinder 401 experiences a downward relative displacement due to inertia, causing the blocking rod 404 to drive the piston disc 412 to compress the adjusting spring 409 downwards. When the telescopic shaft 202 descends rapidly, the guide cylinder 401 experiences an upward relative displacement due to inertia, causing the blocking rod 404 to drive the piston disc 412 to stretch the adjusting spring 409 upwards. The adjusting spring 409 absorbs the impact energy generated by instantaneous acceleration through its own elastic deformation, providing damping and buffering for the axial movement of the blocking rod 404. This effectively slows down the movement speed of the piston disc 412 within the buffer chamber 408, thereby controlling the airflow rate between the air passage of the telescopic shaft 202 and the annular air chamber of the guide cylinder 401, and preventing a sharp increase or decrease in air pressure caused by rapid changes in the internal volume of the guide cylinder 401.

[0043] After the lifting and lowering motion of the telescopic shaft 202 stabilizes, the compressed or stretched adjusting spring 409 slowly releases its elastic potential energy, pushing or pulling the piston disc 412 to smoothly return to its original position, gradually restoring the airflow rate to normal levels. Through the combined action of the buffer chamber 408 and the adjusting spring 409, the air pressure change within the guide cylinder 401 remains smooth and controllable regardless of whether the telescopic shaft 202 is in a rapid lifting or constant-speed motion, achieving a smooth transition between the suction and exhaust processes. This avoids problems such as fluctuating airflow strength, momentary flow interruption, or pressure overload caused by sudden changes in the speed of the telescopic shaft 202, ensuring that the airflow ejected from the exhaust port 403 of the guide cylinder 401 always maintains a stable and sufficient pressure and flow rate, providing a continuous and stable self-cleaning effect for the surface of the telescopic shaft 202.

[0044] Furthermore, the buffer chamber 408 is connected to the inner cavity of the guide cylinder 401. By connecting the two cavities, the space inside the entire guide cylinder 401 can be utilized more fully, maximizing the gas storage capacity and thus providing a stable gas source for the subsequent dust removal of the telescopic shaft 202. Specifically, several connecting holes 413 are provided on the barrier rod 404, which connect the inner cavity of the barrier rod 404 to the buffer chamber 408, thereby achieving communication between the buffer chamber 408 and the inner cavity of the guide cylinder 401.

[0045] like Figure 1 As shown, there are at least two dust blowing assemblies 4, circumferentially spaced on the outer ring of the cylinder 2. Each dust blowing assembly 4 specifically consists of a guide cylinder 401, a guide rod 402, and a blocking rod 404. In this embodiment, there are three dust blowing assemblies 4, circumferentially spaced on the base 1 of the outer ring of the cylinder 201. A reinforcing plate 6 is provided between the upper end of the guide cylinder 401 and the cylinder 201. The reinforcing plate 6 has four through holes: a central through hole at the center of the reinforcing plate 6 and three outer ring through holes surrounding the central through hole. The distance between the outer ring through holes and the central through hole is equal to the distance between the central axis of the cylinder 201 and the central axis of the guide cylinder 401. The inner surfaces of the four through holes require precision machining. The reinforcement plate 6 can further improve the parallelism of the three guide cylinders 401 relative to the cylinder 201, thereby maintaining a relatively stable parallelism when the telescopic shaft 202 and the guide rod 402 slide up and down, and preventing the guide rod 402 from tilting and affecting the lifting and lowering of the telescopic shaft 202.

[0046] Furthermore, to ensure the internal sealing of the guide cylinder 401 and to prevent gas leakage from affecting the gas supply during subsequent gas extraction, corresponding sealing rings are provided at the ends of components capable of relative sliding. For example... Figure 3 As shown, sealing rings are fitted at the upper and lower ends of the piston disc 412, and a sealing ring is provided at the lower end of the guide rod 402, which has the thickest overall thickness and the best sealing effect. At the same time, a sealing ring is also provided at the end of the barrier rod 404 located in the inner cavity of the guide rod 402.

[0047] By setting multiple sealing rings to seal different cavities, the gas in different cavities can be effectively prevented from escaping when the guide rod 402 moves up and down and drives the barrier rod 404 to slide up and down. This ensures that the gas can be stored in the inner cavity of the guide cylinder 401 during the suction process, thereby providing a stable gas source for subsequent exhaust and dust removal, while preventing pressure leakage during exhaust.

[0048] like Figure 3As shown, a sealing plug 410 is connected to the upper end of plug 407 via a connecting rod. The distance between the sealing plug 410 and the plug is constant, which can separate the upper section and the lower section of the guide rod 402. At the same time, a thrust spring 411 is installed in the inner cavity of the guide rod 402 above the sealing plug 410. The thrust spring 411, together with the sealing plug 410 and the weight of plug 407, pushes it down, so that plug 407 can block the air outlet under normal conditions.

[0049] In a specific implementation, the thrust spring 411 itself has a limited thrust. It must be ensured that the thrust spring 411 applies to the plug 407 through the sealing plug 410 is always less than the pressure generated when the air in the bottom cavity of the guide cylinder 401 is compressed as the guide rod 402 slides down. Therefore, when the guide rod 402 slides down and compresses the air in the cavity of the guide cylinder 401, the compressed air can smoothly push the plug 407 open to exhaust air.

[0050] Specifically, in this embodiment, the length of the connecting rod used to connect the sealing plug 410 and the second plug 407 should be between one and 0.5 times the distance between adjacent vent holes 403 opened on the guide rod 402. When the guide rod 402 slides down, it compresses the gas inside the guide cylinder 401. The compressed gas pushes open the second plug 407, causing the second plug 407 and the sealing plug 410 to slide upwards synchronously relative to the guide rod 402 by a certain distance. This opens the vent hole 403 located between the second plug 407 and the sealing plug 410, and the airflow is discharged from the vent hole 403. As the guide rod 402 continues to slide downwards, the opened vent hole 403 also slides down and enters the guide cylinder 401, where it is resealed. The vent hole 403 located above this vent hole 403 moves to the space between the second plug 407 and the sealing plug 410, and the gas is discharged from this vent hole 403.

[0051] Throughout the process described above, the sliding of the guide rod 402 allows for the switching of different exhaust ports 403, ensuring that regardless of the extension length of the guide rod 402, the final exhaust port 403 remains at the position closest to the upper end of the guide cylinder 401, thereby ensuring that the ejected gas is always directed towards the section of the telescopic rod closest to the end of the cylinder 2.

[0052] The base 1 has a cavity at its bottom that communicates with the inner cavity of the guide cylinder 401. A filter plate 7 for filtering air is installed inside the cavity at the bottom of the base 1. The filter plate 7 is mainly used to filter dust particles in the air; therefore, it can be made of polypropylene board with high ventilation efficiency and low cost. By stacking multiple layers of filter plates 7, dust particles in the air can be effectively removed, thus keeping the airflow drawn into the guide cylinder 401 relatively pure.

[0053] It should be noted that in the above embodiment, the airflow direction of the three dust blowing components 4 is all towards the axis of the telescopic rod, and the inclined direction of their exhaust holes 403 is upward. Therefore, when the guide rod 402 pushes the gas in the guide cylinder 401 to be discharged, the three airflows blow towards the telescopic rod from three directions simultaneously, which can generate a certain amount of convection at the telescopic rod position. Since the flow direction of the three airflows is inclined upward, the converging airflow can eventually flow upward along the telescopic rod, thereby achieving dust removal for a longer section of the telescopic rod. On the other hand, the airflow convection can form an air curtain on the outer ring of the telescopic rod, thereby isolating external dust and reducing the amount of dust that subsequently accumulates on the telescopic rod.

[0054] This application also relates to a forklift lifting mast, on which an intermediate lifting cylinder is installed for driving itself to rise or fall.

[0055] Specifically, in this embodiment, the lifting mast includes lifting forks 8 for receiving goods and a mast body for guiding the lifting forks 8, the mast body being fixedly mounted on the forklift 9. For example... Figure 4 As shown, in the drive sprocket assembly 3, one end of the transmission chain 302 is connected to the lifting fork 8, and the other end is fixed on the base 1. The drive wheel 301 is pushed up by the telescopic shaft 202, which in turn drives the transmission chain 302 to drive relative to the drive wheel 301, so that the section of the transmission chain 302 connected to the lifting fork 8 becomes shorter, thereby lifting the entire lifting fork 8.

[0056] In the above embodiment, two push cylinders 10 are also provided on the mast body. The cylinder body 2 of the push cylinder 10 is connected to the forklift 9 body. By pushing the cylinder 10, the tilt angle of the entire mast body can be controlled, so that after the forks take over the goods, the entire mast body can be tilted towards the forklift 9, changing the entire load-bearing point, thereby reducing the risk of the goods falling during transportation.

[0057] It should be noted that, as Figure 4 The mast shown is a double-rail type with two lifting drives. The mast driven by the middle lifting cylinder is the first section, while the lifting drive of the second section is set on the forklift 9.

[0058] Specifically, the mast body includes a fixed guide bracket 11 and a sliding guide bracket 12. The fixed guide bracket 11 is fixed to the forklift 9, and the base 1 is fixedly connected to the sliding guide bracket 12. The lifting forks 8 are slidably mounted on the sliding guide bracket 12. The lifting forks 8 can be driven to slide along the sliding guide bracket 12 by the intermediate lifting cylinder, while the drive mechanism on the forklift 9 can drive the sliding guide bracket 12 and the lifting forks 8 to slide synchronously.

[0059] like Figure 5 The mast body shown is a single-rail type with only one drive. That is, the mast body is only connected to the forklift 9 by the fixed guide bracket 11, and the lifting fork 8 is directly slidably mounted on the fixed guide bracket 11. The lifting cylinder can drive the entire lifting fork 8 to slide upward along the fixed guide bracket 11.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A middle lifting cylinder for a forklift lifting mast, characterized in that, include: The base (1) is fixedly installed on the lifting mast of the forklift (9); The cylinder body (2) includes a cylinder barrel (201) disposed on the base (1) and a telescopic shaft (202) disposed inside the cylinder barrel (201). The drive sprocket assembly (3) includes a drive wheel (301) that moves up and down synchronously with the telescopic shaft (202) and a transmission chain (302) sleeved on the drive wheel (301). The dust blowing assembly (4) includes a guide cylinder (401) disposed on the base (1) and a guide rod (402) disposed inside the guide cylinder (401). The upper end of the guide rod (402) is connected to the upper end of the telescopic shaft (202) with a mounting plate (5). The drive sprocket assembly (3) is disposed above the mounting plate (5). The guide rod (402) has upwardly inclined exhaust holes (403) equidistantly arranged in the direction of the telescopic shaft (202), and the guide rod (402) is hollow inside and is provided with a barrier rod (404).

2. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The lower end of the cylinder (201) connected to the base (1) is provided with an air inlet (405), the air inlet (405) is provided with a plug (406), the upper end of the barrier rod (404) is provided with an air outlet and a plug (407) is provided at the air outlet.

3. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The barrier rod (404) is hollow inside and is slidably disposed inside the guide cylinder (401). A buffer cavity (408) is provided between one end of the guide rod (401) and the lower end of the guide rod (402). An adjusting spring (409) is provided inside the buffer cavity (408).

4. The intermediate lifting cylinder of a forklift lifting mast according to claim 3, characterized in that: The upper and lower ends of the adjusting spring (409) are fixedly connected to the ends of the guide rod (402) and the barrier rod (404), respectively, and the buffer cavity (408) is connected to the inner cavity of the guide cylinder (401).

5. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The number of exhaust holes (403) is at least five, and they are equidistantly opened on the guide rod (402) along the axial direction of the guide rod (402).

6. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The number of guide cylinders (401) is at least two, which are set on the base (1) of the outer ring of the cylinder (201). A reinforcing plate (6) is provided between the upper end of the guide cylinder (401) and the cylinder (201).

7. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The guide rod (402) is slidably disposed at the end of the inner cavity of the guide cylinder (401) and is fitted with a sealing ring. Both the upper and lower ends of the barrier rod (404) are fitted with sealing rings.

8. The intermediate lifting cylinder of a forklift lifting mast according to claim 2, characterized in that: A sealing plug (410) is connected to the second plug (407). A thrust spring (411) is provided between the upper end of the sealing plug (410) and the upper surface of the inner cavity of the guide rod (402). The thrust force applied by the thrust spring (411) to the second plug (407) is always less than the pressure generated when the air in the bottom cavity of the guide cylinder (401) is compressed when the guide rod (402) slides down.

9. The intermediate lifting cylinder of a forklift lifting mast according to claim 1, characterized in that: The base (1) has a cavity at the bottom that communicates with the inner cavity of the guide cylinder (401), and a filter plate (7) for filtering air is provided in the cavity at the bottom of the base (1).

10. A forklift lifting mast, characterized in that: The forklift lifting mast is equipped with an intermediate lifting cylinder as described in claim 1, which is used to drive the forklift lifting mast to rise or fall.

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