A two-stage cylinder control method

Abstract

The present invention provides a two-stage cylinder control method. When extending, for the first-stage stroke control: the second locking assembly locks the movable rod of the second moving assembly, gas is introduced into the rear end of the cylinder body to push the piston rod of the first moving assembly to extend until the rear end of the piston rod migrates to the front end of the movable rod; for the second-stage stroke control: the restriction of the second locking assembly on the movable rod is released, and the gas introduced into the cylinder body pushes the piston rod and drives the movable rod to extend further forward; when contracting, the gas at the rear end of the cylinder body is released, gas is introduced into the front end of the cylinder body, the gas pushes the piston rod and drives the movable rod to move backward. When the movable rod is locked by the second locking assembly, the gas continues to push the piston rod to move until it contracts to the initial state. When controlling the extension of the piston rod, the movable rod is locked first, so that the piston rod can only extend for one stage. When full extension is required, it is unlocked first to achieve two-stage control.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of pneumatic actuators, and mainly relates to a two-stage cylinder control method. Background Art

[0002] Existing cylinders are generally of one-stage type, reaching the maximum stroke when extended, and only having one stroke. Such cylinders cannot meet the requirements in special scenarios. For example, in the fireproof door and window industry. Doors and windows not only have the function of transmitting light, but also play a role in ventilation and exchanging indoor and outdoor air. Especially in case of a fire, the doors and windows should be opened to the maximum to quickly discharge the high-temperature and toxic gases in the room and relieve the indoor environment. Therefore, the requirements for the opening amplitude of doors and windows are different during daily ventilation and fire ventilation, so there is an urgent need to develop a cylinder with two strokes. Summary of the Invention

[0003] The present invention provides a two-stage cylinder control method. When controlling the piston rod to extend, first lock the movable rod so that the piston rod can only extend for one stage. When full extension is required, unlock it first to achieve two-stage control.

[0004] For the two-stage cylinder control method provided by the present invention, during extension, the first-stage stroke control: the second locking assembly locks the movable rod of the second moving assembly, and gas is introduced into the rear end of the cylinder body to push the piston rod of the first moving assembly to extend until the rear end of the piston rod migrates to the front end of the movable rod; the second-stage stroke control: release the restriction of the second locking assembly on the movable rod, and the gas introduced into the cylinder body pushes the piston rod and drives the movable rod to further extend forward; during contraction, release the gas at the rear end of the cylinder body, introduce gas into the front end of the cylinder body, the gas pushes the piston rod and drives the movable rod to move backward. When the movable rod is locked by the second locking assembly, the gas continues to push the piston rod to move until it contracts to the initial state.

[0005] After the piston rod moves to the first stroke, due to the locking of the movable rod, the piston rod is blocked by the movable rod. In the specific scenario of applying the two-stage cylinder, it is not likely to cause the piston rod to extend too long due to an accident. Only after the piston rod is unlocked can the piston rod extend to the second stroke.

[0006] Preferably, when locked, the second locking pin at the rear end of the movable rod presses the second ball support plug of the second locking assembly backward, and the second limiting ball of the second locking assembly snaps into the second locking groove on the outer wall of the rear end of the second locking pin; the gas at the rear end of the cylinder body enters the second rear accommodating cavity. When the gas pressure is greater than the acting force of the second rear locking slider return spring of the second locking assembly on the second rear locking slider, the gas pushes the second rear locking slider backward, the second limiting ball disengages from the second locking groove, and the second ball support plug of the second locking assembly resets under the action of the second ball support plug return spring. The second limiting ball is restricted in the space formed by the second ball support plug, the second rear locking slider, and the inner wall of the second rear accommodating cavity, thereby releasing the restriction of the second locking assembly on the movable rod.

[0007] Preferably, when the piston rod contracts to the initial state, it is locked by the first locking assembly. When locked, the first locking pin at the rear end of the piston rod presses the first ball support plug of the first locking assembly backward, and the first limiting ball of the first locking assembly snaps into the first locking groove; the gas at the rear end of the cylinder body enters the first rear accommodating cavity. When the gas pressure is greater than the acting force of the first rear locking slider return spring of the first locking assembly on the first rear locking slider, the gas pushes the first rear locking slider backward, the first limiting ball disengages from the first locking groove, and the first ball support plug of the first locking assembly resets under the action of the first ball support plug return spring. The first limiting ball is restricted in the space formed by the first ball support plug, the first rear locking slider, and the inner wall of the first rear accommodating cavity, thereby releasing the restriction of the first locking assembly on the piston rod.

[0008] Preferably, the first rear accommodating cavity is communicated with the second rear accommodating cavity, and the acting force of the second rear locking slider return spring on the second rear locking slider is greater than the acting force of the first rear locking slider return spring on the first rear locking slider; first, introduce gas with a pressure greater than the acting force of the first rear locking slider return spring and less than the acting force of the second rear locking slider return spring. After the piston rod extends to the specified position in the first stroke, then introduce gas with a pressure greater than the acting force of the second rear locking slider return spring. In this solution, no high-pressure opening valve is provided, but the first rear accommodating cavity is directly communicated with the second rear accommodating cavity. Then, to unlock the piston rod first and then the movable rod, the pre-tightening force of the second rear locking slider return spring needs to be set larger. Of course, it is also possible to introduce gas with a relatively high pressure at the beginning to achieve unlocking together.

[0009] Preferably, the first rear accommodation cavity and the second rear accommodation cavity are communicated through a high-pressure opening valve. First, a gas with a pressure greater than the acting force of the first rear locking slider return spring and less than the acting force required to open the high-pressure opening valve is introduced. After the piston rod extends to the specified position of the first-stage stroke, a gas with a pressure sufficient to open the high-pressure opening valve is then introduced, so that the first rear accommodation cavity and the second rear accommodation cavity are communicated.

[0010] Preferably, the high-pressure opening valve includes a valve body, a high-pressure valve piston, and a high-pressure valve return spring. A high-pressure valve piston accommodation cavity with a pressure relief hole is formed in the valve body. The high-pressure valve piston is arranged in the high-pressure valve piston accommodation cavity, dividing the high-pressure valve piston accommodation cavity into front and rear parts; the high-pressure valve piston accommodation cavity is communicated with the first rear accommodation cavity and the second rear accommodation cavity through a second air passage and a third air passage respectively, and the high-pressure valve piston accommodation cavity is also communicated with the second rear accommodation cavity through a fourth air passage;

[0011] When locking, the gas at the rear end of the release cylinder body is released to relieve the pressure of the first rear accommodation cavity. The high-pressure valve piston is reset under the action of the high-pressure valve return spring. The high-pressure valve piston separates the second air passage and the third air passage. The fourth air passage, the rear part of the high-pressure valve piston accommodation cavity, and the pressure relief hole are communicated. The second rear accommodation cavity is depressurized through the fourth air passage, the high-pressure valve piston accommodation cavity, and the pressure relief hole; when unlocking, the gas pressure entering the front part of the high-pressure valve piston accommodation cavity from the first rear accommodation cavity through the second air passage is greater than the acting force of the high-pressure valve return spring, so that the second air passage, the front part of the high-pressure valve piston accommodation cavity, and the third air passage are communicated, and the high-pressure valve piston blocks the fourth air passage.

[0012] After the high-pressure opening valve is provided, the unlocking of the piston rod and the unlocking of the movable rod can be carried out simultaneously or separately. When the gas pressure introduced into the first rear accommodation cavity is greater than the acting force of the high-pressure valve return spring, the gas enters the high-pressure valve piston accommodation cavity through the second air passage and then enters the second rear accommodation cavity through the third air passage. At this time, the piston rod and the movable rod are basically unlocked synchronously. At this time, the piston rod can be pushed out by the piston at one time instead of having a two-stage stroke. It is also possible to first introduce a gas with a slightly lower pressure, which is not enough to push the high-pressure valve piston, so as to unlock the piston rod first, and then introduce a gas with a slightly higher pressure to push the high-pressure valve piston and unlock the movable rod. It should be noted that the word "high-pressure" in the high-pressure opening valve does not mean how large the pressure of the valve should be or what range it should meet, but is just a name. How much pressure of the gas needs to be introduced to push the high-pressure valve piston mainly depends on the acting force of the high-pressure valve return spring. That is to say, after the high-pressure opening valve is provided, the present invention can be used as a two-stage cylinder or as an ordinary one-stage cylinder and can be applied to various uses.

[0013] Preferably, after the piston rod extends forward to the in-place position, it is locked by the front locking assembly. When locking, the front locking steel ball of the front locking assembly is snapped into the front locking groove on the piston rod; the gas introduced into the front end of the cylinder body enters the front accommodating cavity, and this gas pushes the front locking slider of the front locking assembly to move forward to the front end, and the front locking steel ball of the front locking assembly disengages from the front locking groove, thereby releasing the restriction on the piston rod.

[0014] The present invention is provided with a second locking assembly for locking the second moving assembly at the rear end of the rear end cover. When the first stage extends to the end of the movable rod, after the second moving assembly is unlocked, the second stage extends completely, realizing the two-stage extension control of the cylinder. The first moving assembly can also be locked, which is used in the fire door and window industry. Locking the first moving assembly can prevent the doors and windows from being blown open by the wind. A front retracting assembly can also be provided at the front end to lock the piston rod that has extended completely, preventing the doors and windows from being blown closed by the wind. Brief Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of the present invention;

[0016] Figure 2 is a schematic structural diagram of the first moving assembly of the present invention;

[0017] Figure 3 is a schematic structural diagram of the second moving assembly of the present invention;

[0018] Figure 4 is a schematic structural diagram of the first locking assembly and the second locking assembly at the rear end of the present invention;

[0019] Figure 5 is a schematic structural diagram of the front retracting assembly at the front end of the present invention;

[0020] Figure 6 is a state diagram when the first moving assembly and the second moving assembly of the present invention are locked simultaneously;

[0021] Figure 7 is a state diagram when the first moving assembly of the present invention is unlocked and the second moving assembly is locked;

[0022] Figure 8 is a state diagram when the first moving assembly and the second moving assembly of the present invention are unlocked simultaneously;

[0023] Figure 9 is a state diagram when the front locking assembly of the present invention is unlocked.

[0024] In the figure: 1 - cylinder body; 2 - front end cover; 2.1 - front seal cover; 2.2 - fifth air passage; 3 - rear end cover; 3.1 - first rear accommodating cavity; 3.2 - first rear seal cover; 3.3 - first air passage; 4 - moving assembly accommodating cavity;

[0025] 5 - First moving component; 5.1 - Piston; 5.2 - Piston rod; 5.3 - Adapter; 5.4 - Eyebolt; 5.5 - First locking pin; 5.6 - First limiting end face; 5.7 - First locking groove; 5.8 - Front locking groove;

[0026] 6 - Second moving component; 6.1 - Movable rod; 6.2 - Second locking pin; 6.3 - Second limiting end face; 6.4 - Limiting protrusion; 6.5 - Second locking groove;

[0027] 7 - First locking assembly; 7.1 - First limiting steel ball; 7.2 - First rear locking slider; 7.3 - First rear locking slider return spring; 7.4 - First steel ball support plug; 7.5 - First steel ball support plug return spring; 7.6 - First steel ball support plug accommodation cavity;

[0028] 8 - Second locking assembly; 8.1 - Second limiting steel ball; 8.2 - Second rear locking slider; 8.3 - Second rear locking slider return spring; 8.4 - Second steel ball support plug; 8.5 - Second steel ball support plug return spring; 8.6 - Second steel ball support plug accommodation cavity;

[0029] 9 - Front locking assembly; 9.1 - Front locking slider; 9.2 - Front locking steel ball; 9.3 - Front locking slider return spring; 9.4 - Front locking bolt;

[0030] 10 - Second locking assembly housing; 10.1 - Second rear accommodation cavity; 10.2 - Second rear cover; 10.3 - Third air passage; 10.4 - Fourth air passage;

[0031] 11 - High - pressure opening valve; 11.1 - Valve body; 11.2 - High - pressure valve piston; 11.3 - High - pressure valve return spring; 11.4 - High - pressure valve piston accommodation cavity; 11.5 - Pressure relief hole;

[0032] 12 - Second air passage. Detailed implementation mode

[0033] The present invention provides a two - stage cylinder with two - stage stroke.

[0034] It includes a cylinder block 1, a front end cover 2 is arranged at the front end of the cylinder block 1, a rear end cover 3 is arranged at the rear end of the cylinder block 1, a moving component accommodating cavity 4 is arranged inside the cylinder block 1, a first moving component 5 moving along the axial direction of the cylinder block is arranged inside the moving component accommodating cavity 4, and a first locking component 7 matching the first moving component 5 is arranged on the rear end cover 2. A second moving component 6 is movably connected inside the first moving component 5, and a second locking component 8 matching the second moving component 6 is arranged at the rear end of the first locking component 7. The first locking component 7 unlocks the first moving component 5, the first moving component 5 moves forward to the front end of the second moving component 6 (at this time the second moving component is locked by the second locking component), the second locking component 8 unlocks the second moving component 6, and the second moving component 6 moves forward together with the first moving component 5 until the first moving component 5 abuts against the front end cover 2.

[0035] Corresponding locking components can be provided for both the first moving component and the second moving component for locking and unlocking, or only a locking component can be provided for the second moving component. If the present invention is applied to fire doors and windows, strong winds may blow the doors and windows open, so when the doors and windows are closed, the first moving component also needs to be locked, and usually two locking components are provided.

[0036] As Figure 2 shown, the first moving component 5 includes a piston 5.1 and a piston rod 5.2. The rear end of the piston rod 5.2 is connected to the piston 5.1. The piston 5.1 is located inside the moving component accommodating cavity 4 and can reciprocate axially along the cylinder block 1, and the front end of the piston rod 5.2 extends outside the front end cover 2. A ring screw 5.4 is connected to the front end of the piston rod 5.2 through an adapter 5.3. A first locking pin 5.5 is arranged at the rear end of the piston rod 5.2. The first locking pin 5.5 can be integrally formed with the piston rod 5.2 or can adopt a split design. For the convenience of processing, the split design is adopted in this embodiment. Both the piston rod 5.2 and the first locking pin 5.5 are hollow structures. Since the inner diameter of the first locking pin 5.5 is smaller than the inner diameter of the piston rod, a first limiting end face 5.6 is formed at the front end of the first locking pin 5.5. A first locking groove 5.7 is arranged on the outer periphery at the rear end of the first locking pin 5.5. A front locking groove 5.8 is arranged on the outer periphery of the rear part of the piston rod 5.2.

[0037] As Figure 3As shown in the figure, the second moving component 6 includes a movable rod 6.1. A second locking pin 6.2 is provided at the rear end of the movable rod 6.1. The second locking pin 6.2 can be integrally formed with the movable rod 6.1 or can be designed as a separate part. For the convenience of processing, the separate part design is adopted in this embodiment. The outer diameter of the second locking pin 6.2 is larger than that of the movable rod 6.1, so that a second limiting end face 6.3 is formed at the front end of the second locking pin. The movable rod 6.1 is arranged in the hollow inner cavity of the piston rod 5.2 and the first locking pin 5.5. A limiting protrusion 6.4 is provided at the front end of the movable rod 6.1. When the movable rod 6.1 moves away from the piston rod 5.2, when the limiting protrusion 6.4 abuts against the first limiting end face 5.6, the two rods extend to the longest. When the movable rod 6.1 moves towards the piston rod 5.2, when the rear end face of the first locking pin 5.5 abuts against the second limiting end face 6.3, the two rods contract to the shortest. The outer diameter of the movable rod 6.1 matches the inner diameter of the first locking pin 5.5, so that there is a certain frictional force between the movable rod and the first locking pin, and a certain force is required to make the two move relative to each other. A second locking groove 6.5 is provided on the outer periphery of the rear end of the second locking pin 6.2.

[0038] As Figure 4 shown in the figure, a first rear accommodating cavity 3.1 is provided at the rear end of the rear end cover 3. The first locking assembly 7 is installed in the first rear accommodating cavity 3.1 and includes a first limiting steel ball 7.1, a first rear locking slider 7.2, a first rear locking slider return spring 7.3, a first steel ball support plug 7.4, and a first steel ball support plug return spring 7.5. The first rear locking slider 7.2 can move back and forth in the first rear accommodating cavity 3.1. A first steel ball support plug accommodating cavity 7.6 is provided on the inner side of the front end of the first rear locking slider 7.2. The first steel ball support plug 7.4 is arranged in the first steel ball support plug accommodating cavity 7.6. A first steel ball support plug return spring 7.5 is provided between the first steel ball support plug 7.4 and the first rear locking slider 7.2. A first steel ball accommodating groove is provided at the front end of the first steel ball support plug accommodating cavity 7.6. An inclined surface is provided at the front end of the first steel ball accommodating groove. The first limiting steel ball 7.1 is located in the first steel ball accommodating groove. The inclined surface is provided to make it easy for the first limiting steel ball to enter and exit the first steel ball accommodating groove. When locking, a part of the first limiting steel ball will be stuck in the first locking groove. A first rear cover 3.2 is installed at the rear end of the rear end cover 3. The first rear locking slider return spring 7.3 is arranged between the first rear cover 3.2 and the first rear locking slider 7.2. A first air passage 3.3 is provided on the rear end cover 3 to communicate the rear end of the moving component accommodating cavity 4 with the front end of the first rear accommodating cavity 3.1. The rear end of the moving component accommodating cavity 4 is communicated with the first air inlet through the air passage. The first air inlet can be opened on the rear end cover, or on the cylinder block or on the front end cover. A sealing ring is provided between the first rear locking slider 7.2 and the inner wall of the rear end cover 3.

[0039] The rear end of the first rear locking slider 7.2 extends out of the rear end cover 3. A second locking component housing 10 is fixedly connected to the rear end of the first rear locking slider 7.2. A second rear accommodation cavity 10.1 is provided at the rear end of the second locking component housing 10, and the second locking component 8 is installed in the second rear accommodation cavity 10.1. The second locking component 8 includes a second limiting steel ball 8.1, a second rear locking slider 8.2, a second rear locking slider return spring 8.3, a second steel ball support plug 8.4, and a second steel ball support plug return spring 8.5. The second rear locking slider 8.2 can move back and forth in the second rear accommodation cavity 10.1. A second steel ball support plug accommodation cavity 8.6 with an opening facing forward is formed in the second rear locking slider 8.2. The second steel ball support plug 8.4 is arranged in the second steel ball support plug accommodation cavity 8.6, and a second steel ball support plug return spring 8.5 is provided between the second steel ball support plug 8.4 and the second rear locking slider 8.2. A second steel ball accommodation groove is provided at the front end of the second steel ball support plug accommodation cavity 8.6, and an inclined surface is provided at the front end of the second steel ball accommodation groove. The second limiting steel ball 8.1 is located in the second steel ball accommodation groove. The inclined surface is provided to enable the second limiting steel ball to easily enter and exit the second steel ball accommodation groove. When locking, a part of the second limiting steel ball will be stuck in the second locking groove. A second rear cover 10.2 is installed at the rear end of the second locking component housing 10, and the second rear locking slider return spring 8.3 is arranged between the second rear cover 10.2 and the second rear locking slider 8.2. A sealing ring is provided between the second rear locking slider 8.2 and the second locking component housing 10. A high-pressure opening valve 11 is also installed on the second locking component housing 10, including a valve body 11.1, a high-pressure valve piston 11.2, and a high-pressure valve return spring 11.3. A high-pressure valve piston accommodation cavity 11.4 is provided in the valve body 11.1, and a sealing ring is provided between the outer periphery of the high-pressure valve piston and the valve body. A high-pressure valve return spring 11.3 is provided between the high-pressure valve piston 11.2 and the rear end of the high-pressure valve piston accommodation cavity 11.4, and a pressure relief hole 11.5 communicating with the outside is provided at the rear end of the high-pressure valve piston accommodation cavity 11.4. A second air passage 12 communicating the front end of the high-pressure valve piston accommodation cavity 11.4 with the first accommodation cavity 3.1 is provided on the first rear locking slider 7.2, the second locking component housing 10, and the valve body. A third air passage 10.3 communicating the front end of the high-pressure valve piston accommodation cavity 11.4 with the second rear accommodation cavity 10.1 is provided on the second locking component housing 10. A fourth air passage 10.4 communicating the rear end of the high-pressure valve piston accommodation cavity 11.4 with the second rear accommodation cavity 10.1 is also provided on the second locking component housing 10. The second locking component housing 10 and the first rear locking slider 7.2 are arranged as hollow structures, and through holes for the second locking pin 6.5 at the rear end of the movable rod to pass through are provided. A sealing ring is provided between the rear end face of the first rear locking slider 7.2 and the second locking component housing 10. The inner diameter of the sealing ring matches the outer diameter of the second locking pin. When the second moving component is locked, it prevents gas from entering the second rear accommodation cavity from the first accommodation cavity through the gap between the outer diameter of the second locking pin and the inner wall of the first rear locking slider.

[0040] When the gas in the first rear accommodation cavity enters the front end of the high-pressure valve piston accommodation cavity 11.4 through the second air passage 12, the gas pressure is greater than the acting force of the high-pressure valve return spring. The gas pushes the high-pressure valve piston to move backward, so that the second air passage, the front end of the high-pressure valve piston accommodation cavity, and the third air passage 10.3 are connected. The high-pressure valve piston 11.2 blocks the fourth air passage 10.4, and the gas in the second rear accommodation cavity 10.1 cannot overflow through the fourth air passage via the pressure relief hole 11.5. If the gas pressure is less than the acting force of the high-pressure valve return spring, the high-pressure valve return spring 11.3 pushes the high-pressure valve piston to reset. The high-pressure valve piston blocks the third air passage 10.3, and the gas cannot enter the second rear accommodation cavity. The second rear accommodation cavity is connected to the pressure relief hole through the fourth air passage.

[0041] As Figure 5 , 9 shown, a front accommodation cavity is provided at the front end of the front end cover 2. The front locking assembly 9 is installed in the front accommodation cavity and includes a front locking slider 9.1, front locking steel balls 9.2, and a front locking slider return spring 9.3. A front seal cover 2.1 is provided at the front end of the front end cover 2. The front locking slider return spring 9.3 is arranged between the front seal cover 2.1 and the front locking slider 9.1. A front locking steel ball accommodation groove is provided on the inner side of the rear end of the front locking slider 9.1. A front locking bolt 9.4 extending outside the front end cover is also connected to the front locking slider 9.1. A kidney-shaped hole for the front locking bolt 9.4 to move back and forth is provided on the front end cover 9.1. Thus, the front locking slider can be manually pushed by the front locking bolt, so that the front locking steel balls are disengaged from the front locking grooves 5.8 to unlock the piston rod. The front locking steel balls 9.2 are matched with the front locking grooves 5.8 on the piston rod 5.2. The front accommodation cavity is connected to the front end of the moving component accommodation cavity 4 through a fifth air passage 2.2. The fifth air passage 2.2 is connected to the second air inlet, and the second air inlet is provided on the front end cover.

[0042] The piston 5.1 divides the moving component accommodation cavity 4 into two parts, front and rear. The high-pressure valve piston 11.2 divides the high-pressure valve piston accommodation into two parts, front and rear. The two parts are opposite to each other, and the area will change as the piston 5.1 and the high-pressure valve piston 11.2 move.

[0043] Now in combination with Figure 6 , 7 , 8, the working principle of the two-stage cylinder is described.

[0044] Contracted state: As Figure 6As shown, the first limiting steel ball 7.1 is located in the first locking groove 5.7 of the first locking pin 5.5. The first rear locking slider 7.2 abuts against the front wall of the first rear accommodating cavity under the action of the first rear locking slider return spring 7.3, and restricts the first limiting steel ball 7.1 from sliding out of the first locking groove 5.7, thereby locking the first moving component. The first steel ball support plug 7.4 abuts against the rear end of the first locking pin 5.5 under the action of the first steel ball support plug return spring 7.5. The second limiting steel ball 8.1 is located in the second locking groove of the second locking pin 6.2. The second rear locking slider 8.2 abuts against the front wall of the second rear accommodating cavity under the action of the second rear locking slider return spring 8.3, and restricts the second limiting steel ball 8.1 from sliding out of the second locking groove, thereby locking the second moving component. The second steel ball support plug 8.4 abuts against the rear end of the second locking pin 6.2 under the action of the second steel ball support plug return spring 8.5.

[0045] Unlocking of the first moving component: As shown in Figure 6 , 7 , compressed gas at 7 bar enters from the first air inlet communicating with the rear end of the moving component accommodating cavity 4, and the compressed gas enters the first rear accommodating cavity 3.1 through the first air passage 3.3, pushing the first rear locking slider 7.2 backward, thereby releasing the restriction on the first limiting steel ball 7.1, which slides out of the first locking groove 5.7. After the first moving component is unlocked, the compressed gas pushes the piston 5.1, causing the first moving component to move forward. At the same time, the first steel ball support plug 7.4 moves forward under the action of the first steel ball support plug return spring 7.5 until it abuts against the first limiting steel ball 7.1, restricting the first limiting steel ball 7.1 within the space enclosed by the first steel ball support plug 7.4, the front wall of the first rear accommodating cavity, and the first rear locking slider 7.2, preventing the first limiting steel ball 7.1 from falling into the middle and losing its limiting function. The first moving component moves forward until the first limiting end face 5.6 at the front end of the first locking pin 5.5 abuts against the limiting protrusion 6.4 at the front end of the movable rod 6.1. The first stroke of the piston rod extends. At this time, the compressed gas at 7 bar is not sufficient to overcome the acting force of the high-pressure valve piston return spring to push the high-pressure valve piston, and the second moving component remains locked.

[0046] Unlocking of the second moving component: As shown in Figure 7 , 8As shown in the figure, compressed gas at 10 bar enters through the first air inlet connected to the rear end of the moving component accommodation cavity. The compressed gas enters the first rear accommodation cavity 3.1 through the first air passage 3.3, and then reaches the front end of the high-pressure valve piston accommodation cavity through the second air passage 12, pushing the high-pressure valve piston 11.2 backward (the high-pressure valve piston requires high-pressure gas above 10 bar to be pushed open, so the compressed gas at 7 bar cannot push it). The compressed gas enters the second rear accommodation cavity through the third air passage 10.3, thereby pushing the second rear locking slider 8.2 backward, releasing the restriction on the second limiting steel ball 8.1, and sliding out from the second locking groove. After the second moving component is unlocked, the compressed gas pushes the first moving component and then drives the second moving component forward. At the same time, the second steel ball support plug 8.4 moves forward under the action of the second steel ball support plug return spring 8.5 until it abuts against the second limiting steel ball 8.1, restricting the second limiting steel ball 8.1 within the space enclosed by the second steel ball support plug 8.4, the front wall of the second rear accommodation cavity, and the second rear locking slider 8.2, preventing the second limiting steel ball from falling into the middle and losing its limiting function. The first moving component moves forward until the piston 5.1 abuts against the front wall of the moving component accommodation cavity, achieving the extension of the second stroke of the piston rod.

[0047] Piston rod locking: When the piston rod is fully extended, the front locking steel ball 9.2 sinks into the front locking groove 5.8 of the piston rod, locking the piston rod.

[0048] Piston rod and movable rod contraction and reset: Compressed gas at 7 bar enters through the second air inlet connected to the fifth air passage 2.2. The first air inlet connected to the rear end of the moving component accommodation cavity starts to release pressure. The high-pressure valve piston of the high-pressure opening valve resets under the action of the high-pressure valve piston return spring, isolating the second air passage and the third air passage. The gas in the second rear accommodation cavity is released through the fourth air passage 10.4, the high-pressure valve piston accommodation cavity, and the pressure relief hole 11.5. As Figure 9 shown, the compressed gas enters the front accommodation cavity through the fifth air passage 2.2, pushing the front locking slider 9.1 forward, releasing the restriction on the front locking steel ball 9.2, and the front locking steel ball slides out from the front locking groove. The piston rod 5.2 moves backward with the piston 5.1 under the action of the compressed gas, driving the movable rod backward at the same time. As Figure 8 shown, the second locking pin 6.2 of the second moving component passes through the central through holes of the rear end cover, the first rear locking slider, and the second locking component housing, abuts against the second steel ball support plug 8.4 and pushes the second steel ball support plug 8.4 backward until the second limiting steel ball 8.1 sinks into the second locking groove on the second locking pin. The second rear locking slider 8.2 resets under the action of the second rear locking slider return spring 8.3, thereby limiting the second limiting steel ball within the second locking groove to lock the second moving component. Figure 7As shown, after the second moving component is locked, the first moving component continues to move backward. The first locking pin 5.5 passes through the central through-hole of the rear end cover and abuts against the first steel ball support plug 7.4, pushing the first steel ball support plug 7.4 to move backward until the first limiting steel ball 7.1 falls into the first locking groove on the first locking pin 5.5. The first rear locking slider 7.2 is reset under the action of the first rear locking slider return spring 7.3, so that the first limiting steel ball is limited in the first locking groove to lock the first moving component.

[0049] In the above embodiments, locking components are provided for both the first moving component and the second moving component. When it is not necessary to lock the first moving component, the second locking component can be installed on the rear end cover, that is, the second rear accommodating cavity is arranged at the position of the first rear accommodating cavity. In the above embodiments, a high-pressure opening valve is provided, or it can be not provided. In this case, the two moving components are unlocked simultaneously, or gas corresponding to the pressure for opening the high-pressure opening valve can be directly introduced. In the above embodiments, the moving component accommodating cavity, the first rear accommodating cavity, and the second accommodating cavity are connected through an air passage to achieve synchronous control of one air source, or multiple air sources can be provided for separate control. The first locking component and the second locking component can also adopt other existing locking devices. For example, an interference fit method can be adopted, and a slot is provided at the rear end, and unlocking can only occur when the piston driving force is greater than the frictional force.

Claims

1. A two-stage cylinder control method, the two-stage cylinder comprising a cylinder block, a moving component accommodating cavity is provided in the cylinder block, a first moving component is arranged in the moving component accommodating cavity, and a second moving component is movably connected within the first moving component; characterized in that: When extending, control of the first stroke: The second locking assembly locks the movable rod of the second moving assembly, gas is introduced into the rear end of the cylinder block to push the piston rod of the first moving assembly to extend until the rear end of the piston rod migrates to the front end of the movable rod; control of the second stroke: The restriction of the second locking assembly on the movable rod is released, and the gas introduced into the cylinder block pushes the piston rod and drives the movable rod to extend further forward; when contracting, the gas at the rear end of the cylinder block is released, gas is introduced into the front end of the cylinder block, the gas pushes the piston rod and drives the movable rod to move backward, when the movable rod is locked by the second locking assembly, the gas continues to push the piston rod to move until it contracts to the initial state; When the second locking assembly locks the movable rod, the second locking pin at the rear end of the movable rod presses the second ball support plug of the second locking assembly backward, and the second limit ball of the second locking assembly is caught in the second locking groove on the outer wall of the rear end of the second locking pin; The gas at the rear end of the cylinder block enters the second rear accommodation cavity. When the gas pressure is greater than the acting force of the second rear locking slider return spring of the second locking assembly on the second rear locking slider, the gas pushes the second rear locking slider to move backward, the second limit ball disengages from the second locking groove, and the second ball support plug of the second locking assembly returns under the action of the second ball support plug return spring. The second limit ball is restricted in the space formed by the second ball support plug, the second rear locking slider and the inner wall of the second rear accommodation cavity, thereby releasing the restriction of the second locking assembly on the movable rod; When the piston rod contracts to the initial state, it is locked by the first locking assembly. At this time, the first locking pin at the rear end of the piston rod presses the first ball support plug of the first locking assembly backward, and the first limit ball of the first locking assembly is caught in the first locking groove at the rear end of the piston rod; The gas at the rear end of the cylinder block enters the first rear accommodation cavity. When the gas pressure is greater than the acting force of the first rear locking slider return spring of the first locking assembly on the first rear locking slider, the gas pushes the first rear locking slider to move backward, the first limit ball disengages from the first locking groove, and the first ball support plug of the first locking assembly returns under the action of the first ball support plug return spring. The first limit ball is restricted in the space formed by the first ball support plug, the first rear locking slider and the inner wall of the first rear accommodation cavity, thereby releasing the restriction of the first locking assembly on the piston rod; The first rear accommodation cavity communicates with the second rear accommodation cavity, and the acting force of the second rear locking slider return spring on the second rear locking slider is greater than the acting force of the first rear locking slider return spring on the first rear locking slider; First, introduce gas with a pressure greater than the acting force of the first rear locking slider return spring and less than the acting force of the second rear locking slider return spring. When the piston rod extends to the specified position of the first stroke, then introduce gas with a pressure greater than the acting force of the second rear locking slider return spring; or, The first rear accommodation cavity and the second rear accommodation cavity are communicated through a high-pressure opening valve. First, a gas with a pressure greater than the acting force of the first rear locking slider return spring and less than the acting force required to open the high-pressure opening valve is introduced. After the piston rod extends to the specified position of the first-stage stroke, a gas with a pressure sufficient to open the high-pressure opening valve is then introduced, so that the first rear accommodation cavity and the second rear accommodation cavity are communicated.

2. The two-stage cylinder control method according to claim 1, characterized in that: The high-pressure opening valve includes a valve body, a high-pressure valve piston, and a high-pressure valve return spring. A high-pressure valve piston accommodation cavity with a pressure relief hole is provided in the valve body. The high-pressure valve piston is arranged in the high-pressure valve piston accommodation cavity, dividing the high-pressure valve piston accommodation cavity into two parts, front and rear; the high-pressure valve piston accommodation cavity is communicated with the first rear accommodation cavity and the second rear accommodation cavity through a second air passage and a third air passage respectively, and the high-pressure valve piston accommodation cavity is also communicated with the second rear accommodation cavity through a fourth air passage; When the second locking assembly locks the movable rod, the gas at the rear end of the cylinder body is released to relieve the pressure in the first rear accommodation cavity. The high-pressure valve piston is reset under the action of the high-pressure valve return spring. The high-pressure valve piston separates the second air passage and the third air passage. The fourth air passage, the rear part of the high-pressure valve piston accommodation cavity, and the pressure relief hole are communicated, and the second rear accommodation cavity is depressurized through the fourth air passage, the high-pressure valve piston accommodation cavity, and the pressure relief hole; when the second locking assembly unlocks the movable rod, the gas pressure entering the front part of the high-pressure valve piston accommodation cavity from the first rear accommodation cavity through the second air passage is greater than the acting force of the high-pressure valve return spring, so that the second air passage, the front part of the high-pressure valve piston accommodation cavity, and the third air passage are communicated, and the high-pressure valve piston blocks the fourth air passage.

3. The two-stage cylinder control method according to claim 1 or 2, characterized in that: A front end cover is provided at the front end of the cylinder body. A front accommodation cavity is provided at the front end of the front end cover. The front locking assembly is installed in the front accommodation cavity. When the piston rod extends forward in place, it is locked by the front locking assembly. At this time, the front locking steel balls of the front locking assembly are engaged in the front locking grooves on the piston rod; the gas introduced into the front end of the cylinder body enters the front accommodation cavity, and this gas pushes the front locking slider of the front locking assembly forward, and the front locking steel balls of the front locking assembly are disengaged from the front locking grooves, thereby releasing the restriction on the piston rod.

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