Oil cylinder convenient to operate

Abstract

The utility model belongs to the technical field of oil cylinders, and particularly relates to an oil cylinder convenient to operate, which comprises a shell consisting of a base and an outer cylinder barrel, a valve body is fixedly mounted in the shell, a piston rod is arranged in an inner cylinder barrel in a sliding manner, a lower piston is arranged in the base in a sliding manner, a joint is arranged below the valve body, and an inner piston is arranged in the joint in a sliding manner. Oil in the first pressurizing cavity enters the second pressurizing cavity through the first oil channel, and oil in the second pressurizing cavity enters the pressure cavity through the oil inlet channel. When the piston rod needs to move downwards, the lower piston moves upwards until the inner piston pushes the oil inlet valve to open the oil inlet channel, the oil return one-way valve opens the oil return channel, and oil in the pressure cavity returns to the oil storage cavity through the oil inlet channel, the second pressurization cavity and the oil return channel. The piston rod is compact in structure and easy to operate, the piston rod can move upwards and downwards only by treading the pedal assembly, and separate operation is not needed; the pedal force and the lifting speed can be automatically switched between a light load and a heavy load; in order to guarantee safety, the device can descend at a constant speed during descending.

Description

Technical fields:

[0001] This utility model belongs to the field of hydraulic cylinder technology, and specifically refers to a hydraulic cylinder that is easy to operate. Background technology:

[0002] Chinese invention patent (publication number CN118598017A, application date 2024.06.11, publication date 2024.09.06) discloses a 1500LB motorcycle lifting platform, including a frame and a hydraulic mechanism. The frame includes a base; a front support is fixed to the front end of the base by a pin; a rear support is fixed to the rear end of the base by a pin; a lifting arm is inserted into the rear support; a handle is fixedly installed on the rear outer surface of the top of the lifting arm; safety frames are provided on both sides of the lifting arm; three safety pins are fixedly welded to both sides of the base; a platform is provided at the top of the rear and front supports; a support platform is fixedly welded to the inner side of the base; and the support platform... A hydraulic mechanism is installed on the upper side of the platform; the hydraulic mechanism includes an oil reservoir, an oil cylinder is installed inside the oil reservoir, a piston rod is inserted inside the oil cylinder, a pump body is installed on the right side of the oil reservoir, a pump core is inserted inside the pump body, a handle is fixedly installed on the top of the pump core, a return spring is sleeved on the outer surface of the pump body, a lifting foot is inserted inside the handle, a tightening screw is installed inside the oil reservoir at the bottom end of the piston rod, a speed limiting spring is installed on the right side of the tightening screw, a 6mm steel ball is movably attached to the upper side of the speed limiting spring, a return foot pedal is installed at the bottom of the oil reservoir, a return push rod is movably attached to the right side of the return foot pedal, a pin is movably attached to the right side of the return push rod, and a high-pressure steel ball is movably attached to the right side of the pin.

[0003] The drawback of the aforementioned hydraulic mechanism is that lifting the piston rod requires stepping on the lifting pedal, and retracting the piston rod requires stepping on the return pedal. These two operations are separate and complicated. Summary of the Invention:

[0004] The purpose of this invention is to provide an easy-to-operate hydraulic cylinder, in which the piston rod can be moved up and down simply by stepping on the foot pedal assembly, without the need for separate operation, making it easy to operate.

[0005] This utility model is implemented as follows:

[0006] An easy-to-operate hydraulic cylinder includes a housing consisting of a base and an outer cylinder. A valve body is fixedly installed inside the housing. An inner cylinder is fixedly installed at the upper end of the valve body, located inside the outer cylinder. An oil storage chamber is formed between the outer cylinder, the inner cylinder, and the valve body. A piston rod slides inside the inner cylinder, forming a pressure chamber between the piston rod, the inner cylinder, and the valve body. A lower piston slides vertically inside the base, located below the valve body and driven upward by a foot pedal assembly. A connector is provided below the valve body, and an inner piston slides inside the connector. A first pressure chamber is formed between the lower piston, the valve body, the connector, and the housing. A second pressure chamber is formed between the inner piston, the connector, and the valve body. An oil passage is connected between the first and second pressure chambers. The valve body has an oil passage connecting the oil storage chamber and the first pressure chamber, an oil inlet connecting the second pressure chamber and the pressure chamber, and a return oil passage connecting the second pressure chamber and the oil storage chamber. The system includes an oil passage, an oil passage one equipped with an oil passage check valve, an oil passage two equipped with an oil passage valve, an oil inlet valve in the oil inlet passage, and a return oil check valve in the oil return passage. When the piston rod needs to move upward, the foot pedal assembly drives the lower piston upward, compressing the first pressurized chamber. The oil pressure in the first pressurized chamber causes the oil passage valve to block the second oil passage and the oil passage check valve to open the first oil passage. The hydraulic oil in the first pressurized chamber enters the second pressurized chamber through the first oil passage. During the upward movement of the lower piston, the inner piston moves upward, compressing the second pressurized chamber. The oil pressure in the second pressurized chamber causes the oil inlet valve to open the oil inlet passage, and the hydraulic oil in the second pressurized chamber enters the pressure chamber through the oil inlet passage. When the piston rod needs to move downward, the foot pedal assembly drives the lower piston upward until the inner piston pushes the oil inlet valve to open the oil inlet passage and the return oil check valve to open the return oil passage. The hydraulic oil in the pressure chamber returns to the oil storage chamber through the oil inlet passage, the second pressurized chamber, and the return oil passage.

[0007] In the aforementioned easy-to-operate hydraulic cylinder, the valve body is provided with a valve core hole, and the side wall of the valve core hole is provided with an oil inlet hole and an oil outlet hole that are connected to the return oil channel and are arranged opposite to each other. An adjusting valve core is slidably arranged in the valve core hole along the axial direction. The valve core hole on one side of the adjusting valve core is connected to the oil storage chamber, and the valve core hole on the other side is connected to the oil inlet channel. The adjusting valve core includes a frustum section that is arranged opposite to the oil inlet hole. The diameter of the frustum section gradually increases from the side of the valve core hole connected to the oil storage chamber to the other side.

[0008] In the aforementioned easy-to-operate hydraulic cylinder, a spring is provided in the valve core hole, which has elasticity to move the regulating valve core towards the oil inlet channel. The regulating valve core also includes a small cylindrical section with a diameter equal to the minimum diameter of the frustum section and a large cylindrical section with a diameter equal to the maximum diameter of the frustum section. The small cylindrical section is connected to the minimum diameter of the frustum section, and the large cylindrical section is connected to the maximum diameter of the frustum section. The regulating valve core is provided with a convex ring one and a convex ring two that abut against and seal against the side wall of the valve core hole. The convex ring one is located on the side of the small cylindrical section away from the frustum section, and the convex ring two is located on the side of the large cylindrical section away from the frustum section.

[0009] In the aforementioned easy-to-operate hydraulic cylinder, the axial direction of the valve core hole is arranged vertically, and includes a large valve core hole and a small valve core hole. The regulating valve core and spring are arranged in the large valve core hole, the upper end of the large valve core hole is connected to the oil storage chamber, and the regulating valve core is provided with a sliding column. The upper end of the sliding column is inserted into the regulating valve core, and the lower end is slidably disposed in the small valve core hole. The lower end of the small valve core hole is connected to the oil inlet channel.

[0010] In the aforementioned easy-to-operate hydraulic cylinder, an O-ring is fitted around the sliding column to seal the gap between the sliding column and the small valve core hole.

[0011] In the aforementioned easy-to-operate hydraulic cylinder, the oil passage valve includes an oil passage valve core for blocking and opening the second oil passage and a spring second that springs the oil passage valve core to return to the oil storage chamber side. The valve body is provided with a mounting hole, and a pressure reducing valve core is slidably disposed in the mounting hole. The mounting hole on one side of the pressure reducing valve core is connected to the pressure chamber. The end of the pressure reducing valve core away from the pressure chamber is connected to the oil passage valve core. Under heavy load, the pressure reducing valve core pushes the oil passage valve core to open the second oil passage.

[0012] In the aforementioned easy-to-operate hydraulic cylinder, the valve body is provided with an installation sleeve, and a push shaft located between the pressure-reducing valve core and the oil-passing valve core is slidably disposed inside the installation sleeve. A spring is fitted outside the push shaft, which has elasticity to move the push shaft to one side of the pressure-reducing valve core.

[0013] In the aforementioned easy-to-operate hydraulic cylinder, the mounting hole is arranged vertically along the axis, the upper end of the mounting sleeve is open, and the lower end face is provided with an assembly hole for the push shaft to extend out. The upper end of the push shaft is provided with a mounting flange, and the upper end of the spring abuts against the mounting flange and the lower end abuts against the lower end face of the mounting sleeve.

[0014] In the aforementioned easy-to-operate hydraulic cylinder, an O-ring is fitted around the pressure-reducing valve core to seal the gap between the pressure-reducing valve core and the mounting hole.

[0015] In the aforementioned easy-to-operate hydraulic cylinder, the oil valve core is provided with an oil unloading channel that connects the oil storage chamber and the pressurization chamber.

[0016] In the aforementioned easy-to-operate hydraulic cylinder, the oil passage valve core is arranged vertically along its axis. The oil unloading channel includes a vertical hole arranged along the axial direction of the oil passage valve core and a horizontal hole arranged perpendicular to the axial direction of the oil passage valve core. The diameter of the horizontal hole is 0.6mm-0.8mm. The vertical hole is a stepped hole, which includes a small hole at the top and a large hole at the bottom. The horizontal hole is connected to the side wall of the small hole. The diameter of the small hole is 1.0mm-1.4mm, and the diameter of the large hole is 2.0mm-2.4mm.

[0017] In the aforementioned easy-to-operate hydraulic cylinder, the inlet valve includes an inlet valve core for blocking and opening the inlet channel and a spring four that springs back the inlet valve core to the pressure chamber two. The end of the inlet valve core near the pressure chamber two extends out of the valve body. The return check valve includes a return valve core for blocking and opening the return channel and a spring five that springs back the return valve core to the pressure chamber two. The end of the return valve core near the pressure chamber two extends out of the valve body. The spring force of the spring four is much smaller than that of the spring force of the spring five. When the inner piston moves upward and pushes the inlet valve core and the return valve core into the valve body, the inlet valve core opens the inlet channel, and the return valve core opens the return channel.

[0018] In the aforementioned easy-to-operate hydraulic cylinder, the lower piston is a hollow cylindrical shape with an upward-facing opening. A mounting seat is provided inside the lower piston. The mounting seat includes a base plate and a sleeve portion located above the base plate. The inner end face of the lower piston is recessed to form a groove. The base plate has an oil passage hole connecting the first pressure chamber and the groove. The upper end of the sleeve portion is fixedly connected to the lower end of the inner piston, and the upper end of the sleeve portion is located inside the inner piston. The mounting seat has a through hole connecting the groove and the second pressure chamber. The oil passage hole, the groove, and the through hole form the first oil passage channel. The oil passage check valve is located inside the through hole. A spring six, sleeved outside the sleeve portion, is provided between the inner piston and the base plate. When the inner piston pushes the inlet valve and the return check valve, the lower end of the connector abuts against the spring six.

[0019] In the aforementioned easy-to-operate hydraulic cylinder, the sleeve is screwed to the inner piston.

[0020] In the aforementioned easy-to-operate hydraulic cylinder, the through hole is arranged vertically along its axial direction. The oil-passing one-way valve includes a steel ball mounted on a mounting base for sealing and opening the through hole, and a spring that springs the steel ball downwards to return it to its original position.

[0021] In the aforementioned easy-to-operate hydraulic cylinder, the sixth spring is a disc spring washer.

[0022] In the aforementioned easy-to-operate hydraulic cylinder, the lower piston is fitted with an O-ring to seal the gap between the lower piston and the base, and the inner piston is fitted with an O-ring to seal the gap between the inner piston and the connector.

[0023] In the aforementioned easy-to-operate hydraulic cylinder, the lower end of the valve body is screwed to the upper end of the base, the upper end of the valve body is located inside the outer cylinder, and an O-ring is fitted on the valve body to seal the gap between the base and the valve body and to seal the gap between the outer cylinder and the valve body.

[0024] In the aforementioned easy-to-operate hydraulic cylinder, a spring seven is fitted around the connector, with the upper end of the spring seven abutting against the valve body and the lower end abutting against the base plate.

[0025] In the aforementioned easy-to-operate hydraulic cylinder, a base frame is installed below the base. The foot pedal assembly includes a hinge seat one with its lower end hinged to the base frame, and a hinge seat two with its upper end hinged to the hinge seat one. One end of the hinge seat two is hinged to the lower piston, and the other end is hinged to one end of the foot pedal. A torsion spring with elasticity is fitted on the hinge shaft between the hinge seat two and the foot pedal, causing the foot pedal to rotate upward. The end of the foot pedal hinged to the hinge seat two is provided with a limiting plate that abuts against and limits the hinge seat two.

[0026] In the aforementioned easy-to-operate hydraulic cylinder, the lower piston further includes a connecting sleeve disposed under the cylinder body. The base is provided with a waist-shaped hole arranged vertically along its length direction. There are two waist-shaped holes arranged opposite each other. The second hinge seat includes two hinge plates located on both sides of the base and a connecting plate connecting the two hinge plates. The hinge shaft between the second hinge seat and the lower piston passes through one of the hinge plates, one of the waist-shaped holes, the connecting sleeve, the other waist-shaped hole, and the other hinge plate in sequence.

[0027] In the aforementioned easy-to-operate hydraulic cylinder, the base frame includes a horizontal mounting plate and two vertical mounting plates. Each vertical mounting plate is provided with two mounting ears. The lower end of the hinge seat is hinged in one of the mounting ears, and the other mounting ear extends into the base and is hinged to the base. A gap of 0.8mm-1.2mm is left between the bottom surface of the base and the vertical mounting plate.

[0028] In the aforementioned easy-to-operate hydraulic cylinder, the upper end of the outer cylinder is provided with a front end cover. The front end cover includes an outer sealing part and an inner sealing part. The outer sealing part is disposed inside the outer cylinder, and the outer side wall of the outer sealing part is sealed to the inner side wall of the outer cylinder. The upper end of the inner cylinder is disposed inside the inner sealing part, and the inner side wall of the inner sealing part is sealed to the outer side wall of the inner cylinder. The upper end of the piston rod extends out of the front end cover, and the outer side wall of the piston rod abuts against the inner side wall of the front end cover.

[0029] In the aforementioned easy-to-operate hydraulic cylinder, a connecting part is provided at the middle of the upper end of the valve body, the upper end of the inner cylinder is screwed to the inner sealing part and the lower end is screwed to the connecting part, a limiting flange is provided on the outer periphery of the outer sealing part, and the outer cylinder is axially limited between the limiting flange and the base.

[0030] In the aforementioned easy-to-operate hydraulic cylinder, an O-ring is fitted around the outer sealing part to seal the gap between the outer cylinder barrel and the outer sealing part; an O-ring is fitted around the inner cylinder barrel to seal the gap between the inner sealing part and the inner cylinder barrel; and an O-ring is fitted around the piston rod to seal the gap between the piston rod and the front end cover.

[0031] In the aforementioned easy-to-operate hydraulic cylinder, springs one, two, three, four, five, and seven are compression springs.

[0032] The outstanding advantages of this utility model compared to the prior art are:

[0033] 1. This utility model can open the oil inlet channel by pushing the oil inlet valve with the internal piston and open the oil return channel with the return oil check valve, so that the hydraulic oil in the pressure chamber returns to the oil storage chamber through the oil inlet channel, the pressurization chamber and the return oil channel, thereby realizing the downward movement of the piston rod, that is, the upward and downward movement of the piston rod. Only the foot pedal assembly needs to be stepped on, and there is no need to operate separately, so the operation is simple.

[0034] 2. The valve body of this utility model is provided with a valve core hole. The side wall of the valve core hole is provided with an oil inlet hole and an oil outlet hole that are connected to the oil return channel and are arranged opposite to each other. An adjusting valve core is slidably arranged in the valve core hole along the axial direction. The valve core hole on one side of the adjusting valve core is connected to the oil storage chamber, and the valve core hole on the other side is connected to the oil inlet channel. The adjusting valve core includes a frustum section that is arranged opposite to the oil inlet hole. The diameter of the frustum section gradually increases from the side of the valve core hole connected to the oil storage chamber to the other side, so that the piston rod can descend at a constant speed under light load and heavy load.

[0035] 3. The valve body of this utility model is provided with an installation hole, and a pressure reducing valve core is slidably installed in the installation hole. The installation hole on one side of the pressure reducing valve core is connected to the pressure chamber. The end of the pressure reducing valve core away from the pressure chamber is connected to the oil passage valve core. When under heavy load, the pressure reducing valve core pushes the oil passage valve core to open the second oil passage, so that the first pressure chamber is depressurized, thereby allowing the valve to be stepped up with a smaller force when under heavy load.

[0036] 4. The foot pedal assembly of this utility model adopts a folding mechanism design. When working, the foot pedal unfolds and works normally. When not working, the foot pedal automatically folds, saving space. At the same time, the hinge between the foot pedal and the hinge seat adopts a self-lubricating bushing structure, which makes unfolding and folding easy and can extend the service life. Attached image description:

[0037] Figure 1 This is a perspective view of the present invention;

[0038] Figure 2 This is a cross-sectional view of the footless assembly and base frame of this utility model;

[0039] Figure 3 This is a partial sectional view of the present invention from another angle;

[0040] Figure 4 This is a perspective view of the regulating valve core of this utility model;

[0041] Figure 5 This is a perspective view of the foot pedal assembly, base frame, and lower piston of this utility model;

[0042] Figure 6 This is a cross-sectional view of the lower piston and mounting base of this utility model.

[0043] Reference numerals: 1. Base; 2. Outer cylinder; 3. Valve body; 4. Inner cylinder; 5. Oil reservoir; 6. Piston rod; 7. Pressure chamber; 8. Lower piston; 9. Connector; 10. Inner piston; 11. Pressurization chamber one; 12. Pressurization chamber two; 13. Oil passage one; 14. Oil passage two; 15. Oil inlet passage; 16. Oil return passage; 17. Oil check valve; 17a. Steel ball; 17b. Spring Spring 8; 18. Oil passage valve; 18a. Oil passage valve core; 18b. Spring 2; 19. Oil inlet valve; 19a. Oil inlet valve core; 19b. Spring 4; 20. Return oil check valve; 20a. Return oil valve core; 20b. Spring 5; 21. Valve core hole; 22. Oil inlet hole; 23. Oil outlet hole; 24. Adjusting valve core; 24a. Frustum section; 24b. Small cylindrical section; 24c. Large cylindrical section; 2 4d, Convex Ring 1; 24e, Convex Ring 2; 25, Spring 1; 26, Mounting Hole; 27, Pressure Reducing Valve Core; 28, Mounting Sleeve; 29, Push Shaft; 30, Spring 3; 31, Mounting Base; 31a, Base Plate; 31b, Fitting Part; 32, Groove; 33, Oil Pass Hole; 34, Through Hole; 35, Spring 6; 36, Spring 7; 37, Base Frame; 37a, Horizontal Mounting Plate; 37b, Vertical Mounting Plate Mounting plate; 37c, Mounting ear; 38, Hinge seat one; 39, Hinge seat two; 39a, Hinge plate; 39b, Connecting plate; 40, Foot pedal; 41, Torsion spring; 42, Limiting plate; 43, Front end cover; 43a, Outer sealing part; 43b, Inner sealing part; 43c, Limiting flange; 44, Sliding column; 45, Mounting flange; 46, Waist-shaped hole; 47, Oil unloading channel; 48, Connecting part. Detailed implementation method:

[0044] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 —6:

[0045] An easy-to-operate hydraulic cylinder includes a housing consisting of a base 1 and an outer cylinder 2. A valve body 3 is fixedly installed inside the housing. An inner cylinder 4 located inside the outer cylinder 2 is fixedly installed at the upper end of the valve body 3. An oil storage chamber 5 is formed between the outer cylinder 2, the inner cylinder 4, and the valve body 3. A piston rod 6 is slidably mounted inside the inner cylinder 4. A pressure chamber 7 is formed between the piston rod 6, the inner cylinder 4, and the valve body 3. A lower piston 8 is vertically slidably mounted inside the base 1. The lower piston 8 is located below the valve body 3 and is driven upward by a foot pedal assembly. A connector 9 is provided below the valve body 3. The connector 9 has an inner piston 10 slidingly mounted inside. The lower piston 8, valve body 3, connector 9, and outer shell form a pressure chamber 11. The inner piston 10, connector 9, and valve body 3 form a pressure chamber 2 12. An oil passage 13 connects the pressure chamber 11 and pressure chamber 2 12. The valve body 3 has an oil passage 14 connecting the oil storage chamber 5 and pressure chamber 11, an oil inlet passage 15 connecting pressure chamber 2 12 and pressure chamber 7, and a return passage 16 connecting pressure chamber 2 12 and oil storage chamber 5. Oil passage 13 is equipped with an oil passage check valve 17, oil passage 24 is equipped with an oil passage valve 18, oil inlet passage 15 is equipped with an oil inlet valve 19, and oil return passage 16 is equipped with a return check valve 20. When the piston rod 6 needs to move upward, the foot pedal assembly drives the lower piston 8 to move upward, compressing the pressure chamber 11. The oil pressure in the pressure chamber 11 causes the oil passage valve 18 to block the oil passage 24 and the oil passage check valve 17 to open the oil passage 13. The hydraulic oil in the pressure chamber 11 enters the pressure chamber 22 through oil passage 13, and the lower piston... During the upward movement of piston rod 8, the inner piston 10 moves upward, compressing the second pressurizing chamber 12. The oil pressure in the second pressurizing chamber 12 causes the inlet valve 19 to open the inlet channel 15, and the hydraulic oil in the second pressurizing chamber 12 enters the pressure chamber 7 through the inlet channel 15. When piston rod 6 needs to move downward, the foot pedal assembly drives the lower piston 8 to move upward until the inner piston 10 pushes the inlet valve 19 to open the inlet channel 15 and the return check valve 20 to open the return channel 16. The hydraulic oil in the pressure chamber 7 returns to the oil storage chamber 5 through the inlet channel 15, the second pressurizing chamber 12, and the return channel 16.

[0046] The working principle of this utility model is as follows: Figure 1-6 As shown, when the foot pedal assembly is pressed, the foot pedal assembly drives the lower piston 8 to move upward, compressing the first pressure chamber 11. The oil pressure in the first pressure chamber 11 causes the oil valve 18 to block the second oil passage 14 and causes the oil check valve 17 to open the first oil passage 13. The hydraulic oil in the first pressure chamber 11 enters the second pressure chamber 12 through the first oil passage 13. During the upward movement of the lower piston 8, the inner piston 10 is driven to move upward, compressing the second pressure chamber 12. The oil pressure in the second pressure chamber 12 causes the oil inlet valve 19 to open the oil inlet passage 15. The hydraulic oil in the second pressure chamber 12 enters the pressure chamber 7 through the oil inlet passage 15, pushing the piston rod 6 upward.

[0047] Next, press the foot pedal assembly hard. The foot pedal assembly drives the lower piston 8 to move upward until the inner piston 10 pushes the oil inlet valve 19 to open the oil inlet channel 15 and the return oil check valve 20 to open the return oil channel 16. The hydraulic oil in the pressure chamber 7 returns to the oil storage chamber 5 through the oil inlet channel 15, the second pressurization chamber 12, and the return oil channel 16. The piston rod 6 moves downward slowly.

[0048] This utility model has a compact structure and is easy to operate. The piston rod can be moved up and down by simply stepping on the foot pedal assembly, without the need for separate operation.

[0049] Under heavy load, the high oil pressure in pressure chamber 7 leads to a fast hydraulic oil flow rate in the return oil channel, which in turn causes the piston rod 6 to descend at an accelerated rate.

[0050] To prevent the piston rod 6 from descending rapidly under heavy loads due to high oil pressure, such as... Figure 2-4 As shown, the valve body 3 is provided with a valve core hole 21. The side wall of the valve core hole 21 is provided with an oil inlet hole 22 and an oil outlet hole 23 that are connected to the oil return channel 16 and are arranged opposite to each other. An adjusting valve core 24 is slidably arranged in the valve core hole 21 along the axial direction. One side of the valve core hole 21 of the adjusting valve core 24 is connected to the oil storage chamber 5, and the other side of the valve core hole 21 is connected to the oil inlet channel 15. The adjusting valve core 24 includes a frustum section 24a that is arranged opposite to the oil inlet hole 22. The diameter of the frustum section 24a gradually increases from the side of the valve core hole 21 that is connected to the oil storage chamber 5 to the other side. Under heavy load, the oil pressure in pressure chamber 7 is relatively high, that is, the oil pressure in oil inlet channel 15 is relatively high. Under the push of the oil pressure in oil inlet channel 15, the regulating valve core 24 moves to the side of oil storage chamber 5. The diameter of the part of the frustum section 24a opposite to the oil inlet hole 22 becomes larger, which reduces the oil inlet area of ​​the return oil channel 16 entering the oil inlet hole 22 and reduces the oil outlet area entering the oil storage chamber 5 through the oil outlet hole 23. This ensures that the amount of hydraulic oil flowing back from pressure chamber 7 to oil storage chamber 5 remains unchanged, so that the piston rod 6 can descend at a constant speed under heavy load. This ensures that the piston rod 6 can descend at a constant speed under both light and heavy load.

[0051] To allow the piston rod 6 to move quickly downwards under no-load conditions, a spring 25 is provided inside the valve core hole 21, which has elasticity to move the regulating valve core 24 toward the oil inlet channel 15. The regulating valve core 24 also includes a small cylindrical section 24b with the same diameter as the minimum diameter of the frustum section 24a and a large cylindrical section 24c with the same diameter as the maximum diameter of the frustum section 24a. The small cylindrical section 24b is connected to the minimum diameter of the frustum section 24a, and the large cylindrical section 24c is connected to the maximum diameter of the frustum section 24a. The regulating valve core 24 is provided with a convex ring 24d and a convex ring 24e that abut against and seal against the side wall of the valve core hole 21. The convex ring 24d is located on the side of the small cylindrical section 24b away from the frustum section 24a, and the convex ring 24e is located on the side of the large cylindrical section 24c away from the frustum section 24a.

[0052] Furthermore, the valve core hole 21 is arranged vertically along its axis and includes a large valve core hole and a small valve core hole. The regulating valve core 24 and the spring 25 are arranged in the large valve core hole. The upper end of the large valve core hole is connected to the oil storage chamber 5. The regulating valve core 24 is provided with a sliding column 44. The upper end of the sliding column 44 is inserted in the regulating valve core 24, and the lower end slides in the small valve core hole. The lower end of the small valve core hole is connected to the oil inlet channel 15.

[0053] In order to better seal the gap between the sliding post 44 and the small valve core hole, the sliding post 44 is fitted with an O-ring to seal the gap between the sliding post 44 and the small valve core hole.

[0054] The structure of the oil passage valve 18 is as follows: Figure 2 As shown, the oil passage valve 18 includes an oil passage valve core 18a for blocking and opening the second oil passage 14 and a second spring 18b that springs back the oil passage valve core 18a to the side of the oil storage chamber 5. The valve body 3 is provided with a mounting hole 26, and a pressure reducing valve core 27 is slidably disposed in the mounting hole 26. The mounting hole 26 on one side of the pressure reducing valve core 27 is connected to the pressure chamber 7. The end of the pressure reducing valve core 27 away from the pressure chamber 7 is connected to the oil passage valve core 18a. Under heavy load, the pressure reducing valve core 27 pushes the oil passage valve core 18a to open the second oil passage 14, so that the pressure chamber 11 is depressurized, thereby allowing the valve to rise with a smaller force under heavy load. Under heavy load, the oil pressure in pressure chamber 7 is relatively high. The oil pressure in pressure chamber 7 causes the pressure reducing valve core 27 to move towards the oil passage valve core 18a and pushes the oil passage valve core 18a to open the oil passage 14. As the lower piston 8 moves upward, the hydraulic oil in the pressure chamber 11 returns to the oil storage chamber 5 through the oil passage 14, causing the pressure chamber 11 to depressurize. At this time, the oil passage check valve 17 closes the oil passage 13, and the hydraulic oil in the pressure chamber 11 does not enter the pressure chamber 22, which reduces the amount of hydraulic oil entering pressure chamber 7. This makes it easier to push the lower piston 8 and the inner piston 10 upward, which is more labor-saving, but requires repeated pedaling of the foot pedal assembly.

[0055] Under light load, pressurizing chamber 11 and pressurizing chamber 2 work simultaneously, allowing piston rod 6 to rise rapidly.

[0056] The connection structure between the pressure reducing valve core 27 and the oil passage valve core 18a is as follows: Figure 2 As shown, the valve body 3 is provided with an installation sleeve 28, and a push shaft 29 is slidably disposed inside the installation sleeve 28 between the pressure reducing valve core 27 and the oil passing valve core 18a. The push shaft 29 is fitted with a spring 30 that has elasticity to move the push shaft 29 toward the pressure reducing valve core 27.

[0057] The mounting structure of the push shaft 29 and the spring 30 is as follows: the axial direction of the mounting hole 26 is vertically arranged, the upper end of the mounting sleeve 28 is open, and the lower end face is provided with an assembly hole for the push shaft 29 to extend out. The upper end of the push shaft 29 is provided with a mounting flange 45. The upper end of the spring 30 abuts against the mounting flange 45 and the lower end abuts against the lower end face of the mounting sleeve 28.

[0058] In order to better seal the gap between the pressure reducing valve core 27 and the mounting hole 26, an O-ring is fitted on the outside of the pressure reducing valve core 27 to seal the gap between the pressure reducing valve core 27 and the mounting hole 26.

[0059] When unloaded, after the piston rod 6 reaches the top, the pressure chamber 7 is filled with hydraulic oil, and the hydraulic oil in the second pressure chamber 12 can no longer enter the pressure chamber 7. If the foot pedal is pressed, the oil pressure in the second pressure chamber 12 pushes the return valve 18 to open the return channel 16, and the hydraulic oil in the second pressure chamber 12 enters the oil storage chamber 5 through the return channel 16. The oil pressure in the first pressure chamber 11 pushes the oil passage check valve 17 to open the oil passage 13, and the hydraulic oil in the first pressure chamber 11 enters the second pressure chamber 12 through the oil passage 13.

[0060] To reduce the force required to step on the foot pedal assembly when unloaded, the oil valve core 18a is provided with an oil discharge channel 47 connecting the oil storage chamber 5 and the pressurization chamber 11. When pressure relief is required under no-load conditions, the hydraulic oil in the pressurization chamber 11 returns to the oil storage chamber 5 through the oil discharge channel 47, thereby reducing the amount of oil entering the oil storage chamber 5 from the pressurization chamber 2 12 through the return channel 16.

[0061] The specific structure of the oil unloading channel 47: The oil valve core 18a is axially arranged vertically. The oil unloading channel 47 includes a vertical hole arranged along the axial direction of the oil valve core 18a and a horizontal hole arranged perpendicular to the axial direction of the oil valve core 18a. The diameter of the horizontal hole is 0.6mm-0.8mm. The vertical hole is a stepped hole, which includes a small hole at the top and a large hole at the bottom. The horizontal hole is connected to the side wall of the small hole. The diameter of the small hole is 1.0mm-1.4mm, and the diameter of the large hole is 2.0mm-2.4mm. The oil volume in the oil unloading channel 47 is much smaller than the oil volume in the second oil passage 14 opened by the pressure reducing valve core 27 pushing the oil valve core 18a. Therefore, it has little impact on the amount of oil entering the pressure chamber 7 during the upward movement of the piston rod 6.

[0062] In this embodiment, the diameter of the horizontal hole is 0.7 mm, the diameter of the small hole is 1.2 mm, and the diameter of the large hole is 2.2 mm.

[0063] The specific structure of the inlet valve 19 and the return check valve 20 is as follows: Figure 2 , 3As shown, the oil inlet valve 19 includes an oil inlet valve core 19a for blocking and opening the oil inlet channel 15 and a spring 4 19b that springs back the oil inlet valve core 19a to the side of the pressure chamber 2 12. The end of the oil inlet valve core 19a near the pressure chamber 2 12 extends out of the valve body 3. The return oil check valve 20 includes a return oil valve core 20a for blocking and opening the return oil channel 16 and a spring 5 20b that springs back the return oil valve core 20a to the side of the pressure chamber 2 12. The end of the return oil valve core 20a near the pressure chamber 2 12 extends out of the valve body 3. The spring force of the spring 4 19b is much smaller than that of the spring 5 20b. When the inner piston 10 moves upward and pushes the oil inlet valve core 19a and the return oil valve core 20a into the valve body 3, the oil inlet valve core 19a opens the oil inlet channel 15, and the return oil valve core 20a opens the return oil channel 16.

[0064] When the inner piston 10 does not push the inlet valve core 19a and the return valve core 20a into the valve body 3, the oil pressure in the pressure chamber 2 12 can usually only make the inlet valve core 19a open the inlet channel 15, but cannot make the return valve core 20a open the return channel 16, because the elastic force of the fourth spring 19b is much smaller than that of the fifth spring 20b.

[0065] Furthermore, the elastic force of spring 5 20b is greater than or equal to 10 times the elastic force of spring 4 19b. In this embodiment, the elastic force of spring 5 20b is 100N, and the elastic force of spring 4 19b is 6N.

[0066] The structure of the lower piston 8 and the oil passage 13 is as follows: Figure 2 , 3 As shown in Figure 6, the lower piston 8 is a hollow cylindrical shape with an upward-facing opening. A mounting base 31 is provided inside the lower piston 8. The mounting base 31 includes a base plate 31a and a fitting portion 31b located above the base plate 31a. The inner end face of the lower piston 8 is recessed to form a groove 32. The base plate 31a has an oil passage hole 33 connecting the first pressure chamber 11 and the groove 32. The upper end of the fitting portion 31b is fixedly connected to the lower end of the inner piston 10, and the upper end of the fitting portion 31b is disposed inside the inner piston 10. The mounting base 31 has a groove 32 connecting the second pressure chamber 12. The through hole 34, the oil passage hole 33, the groove 32 and the through hole 34 form the oil passage channel 13. The oil passage one-way valve 17 is set in the through hole 34. A spring six 35 is provided between the inner piston 10 and the base plate 31a and is fitted outside the fitting part 31b. When the inner piston 10 pushes the oil inlet valve 19 and the oil return one-way valve 20, the lower end of the connector 9 abuts against the spring six 35, so that the foot pressure when the piston rod 6 moves down is greater than the foot pressure when the piston rod 6 moves up, so that the operator can distinguish whether the piston rod 6 moves up or down when the foot is pressed.

[0067] Connection method between the sleeve part 31b and the inner piston 10: The sleeve part 31b is screwed to the inner piston 10.

[0068] The structure of the oil-passing one-way valve 17: the through hole 34 is arranged vertically along the axis. The oil-passing one-way valve 17 includes a steel ball 17a disposed on the mounting base 31 for blocking and opening the through hole 34, and a spring 17b that springs the steel ball 17a downward to reset it.

[0069] Furthermore, the spring 635 is a butterfly spring washer.

[0070] For better sealing, the lower piston 8 is fitted with an O-ring to seal the gap between the lower piston 8 and the base 1, and the inner piston 10 is fitted with an O-ring to seal the gap between the inner piston 10 and the connector 9.

[0071] For better sealing, the lower end of the valve body 3 is screwed to the upper end of the base 1, and the upper end of the valve body 3 is located inside the outer cylinder 2. The valve body 3 is fitted with an O-ring to seal the gap between the base 1 and the valve body 3 and an O-ring to seal the gap between the outer cylinder 2 and the valve body 3.

[0072] To ensure that the mounting base 31 and lower piston 8 can automatically return to their downward position when the foot pedal assembly is released, a spring 36 is fitted around the connector 9. The upper end of the spring 36 abuts against the valve body 3, and the lower end abuts against the base plate 31a. When the foot pedal assembly is released, the base plate 31a moves downward under the elastic force of the spring 36, which in turn moves the mounting base 31 and the inner piston 10 downward. The space of the first pressure chamber 11 and the second pressure chamber 12 increases, the oil passage valve 18 opens the second oil passage 14, and the oil passage check valve 17 opens the first oil passage 13. The hydraulic oil in the oil storage chamber 5 enters the first pressure chamber 11 through the second oil passage 14, and then enters the second pressure chamber 12 through the first oil passage 13.

[0073] To reduce the lateral space occupied by the pedal assembly, such as Figure 1 , 5 As shown, a base frame 37 is installed below the base 1. The foot pedal assembly includes a hinge seat 38 with its lower end hinged to the base frame 37. A hinge seat 39 is hinged to the upper end of the hinge seat 38. One end of the hinge seat 39 is hinged to the lower piston 8, and the other end is hinged to one end of the foot pedal 40. A torsion spring 41 is fitted on the hinge shaft between the hinge seat 39 and the foot pedal 40, which has elastic force to make the foot pedal 40 rotate upward. The end of the foot pedal 40 that is hinged to the hinge seat 39 is provided with a limiting plate 42 that abuts against and limits the hinge seat 39. When the foot pedal 40 is pressed, it rotates downwards around the hinge axis between itself and the second hinge seat 39 until the limiting plate 42 abuts against the second hinge seat 39. Then, pressing the foot pedal 40 causes the end of the second hinge seat 39 that is hinged to the lower piston 8 to move upwards around the hinge axis between the second hinge seat 39 and the first hinge seat 38, thereby driving the lower piston 8 to move upwards. When the foot pedal 40 is released, it rotates upwards to return to its original position under the elastic force of the torsion spring 41, completing the retraction of the foot pedal 40.

[0074] The foot pedal assembly of this utility model adopts a folding mechanism design. When working, the foot pedal 40 unfolds and works normally. When not working, the foot pedal 40 automatically folds, saving space.

[0075] Furthermore, the hinge between the foot pedal 40 and the hinge seat 39 adopts a self-lubricating bushing structure, which allows for easy unfolding and folding, while also extending the service life.

[0076] The hinge structure between the second hinge seat 39 and the lower piston 8: The lower piston 8 also includes a connecting sleeve disposed under the cylinder. The base 1 is provided with a waist-shaped hole 46 arranged vertically along the length direction. There are two waist-shaped holes 46 arranged opposite each other. The second hinge seat 39 includes two hinge plates 39a located on both sides of the base 1 and a connecting plate 39b connecting the two hinge plates 39a. The hinge axis between the second hinge seat 39 and the lower piston 8 passes through one of the hinge plates 39a, one of the waist-shaped holes 46, the connecting sleeve, the other waist-shaped hole 46, and the other hinge plate 39a in sequence.

[0077] Structure of base frame 37: The base frame 37 includes a horizontal mounting plate 37a and two vertical mounting plates 37b. Each vertical mounting plate 37b is provided with two mounting ears 37c. The lower end of the hinge seat 38 is hinged in one of the mounting ears 37c. The other mounting ear 37c extends into the base 1 and is hinged to the base 1. A gap of 0.8mm-1.2mm is left between the bottom surface of the base 1 and the vertical mounting plate 37b, so that the base 1 can rotate slightly relative to the base frame 37.

[0078] Furthermore, the upper end of the outer cylinder 2 is provided with a front end cover 43, which includes an outer sealing part 43a and an inner sealing part 43b. The outer sealing part 43a is disposed inside the outer cylinder 2, and the outer side wall of the outer sealing part 43a is sealed to the inner side wall of the outer cylinder 2. The upper end of the inner cylinder 4 is disposed inside the inner sealing part 43b, and the inner side wall of the inner sealing part 43b is sealed to the outer side wall of the inner cylinder 4. The upper end of the piston rod 6 extends out of the front end cover 43, and the outer side wall of the piston rod 6 abuts against the inner side wall of the front end cover 43.

[0079] Installation structure of outer cylinder 2 and inner cylinder 4: The valve body 3 is provided with a connecting part 48 at the middle of the upper end. The upper end of the inner cylinder 4 is screwed to the inner sealing part 43b and the lower end is screwed to the connecting part 48. The outer sealing part 43a is provided with a limiting flange 43c on its outer periphery. The outer cylinder 2 is axially limited between the limiting flange 43c and the base 1.

[0080] For better sealing, an O-ring is fitted on the outer sealing part 43a to seal the gap between the outer cylinder 2 and the outer sealing part 43a, an O-ring is fitted on the inner cylinder 4 to seal the gap between the inner sealing part 43b and the inner cylinder 4, and an O-ring is fitted on the piston rod 6 to seal the gap between the piston rod 6 and the front end cover 43.

[0081] Furthermore, spring 1 25, spring 2 18b, spring 3 30, spring 4 19b, spring 5 20b and spring 7 36 are compression springs.

[0082] This invention allows for automatic switching between foot pedal force and lifting speed under light and heavy loads; for safety, it can descend at a constant speed.

[0083] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. A cylinder for ease of operation, characterised in that: The device includes a housing consisting of a base (1) and an outer cylinder (2). A valve body (3) is fixedly installed inside the housing. An inner cylinder (4) located inside the outer cylinder (2) is fixedly installed at the upper end of the valve body (3). An oil storage chamber (5) is formed between the outer cylinder (2), the inner cylinder (4), and the valve body (3). A piston rod (6) is slidably installed inside the inner cylinder (4). A pressure chamber (7) is formed between the piston rod (6), the inner cylinder (4), and the valve body (3). A lower piston (8) is slidably installed vertically inside the base (1). The lower piston (8) is located below the valve body (3) and is driven upward by a foot pedal assembly. A connector (9) is provided below the valve body (3). 9) An inner piston (10) is provided inside. The lower piston (8) forms a pressure chamber one (11) between the valve body (3), the connector (9), and the outer shell. The inner piston (10) forms a pressure chamber two (12) between the connector (9) and the valve body (3). An oil passage one (13) connects the pressure chamber one (11) and the pressure chamber two (12). The valve body (3) is provided with an oil passage two (14) connecting the oil storage chamber (5) and the pressure chamber one (11), an oil inlet passage (15) connecting the pressure chamber two (12) and the pressure chamber (7), and an oil return passage (16) connecting the pressure chamber two (12) and the oil storage chamber (5). Oil passage one (13) is equipped with an oil passage check valve (17), oil passage two (14) is equipped with an oil passage valve (18), oil inlet passage (15) is equipped with an oil inlet valve (19), and oil return passage (16) is equipped with a return oil check valve (20). When the piston rod (6) needs to move upward, the foot pedal assembly drives the lower piston (8) to move upward, compressing the first pressurizing chamber (11). The oil pressure in the first pressurizing chamber (11) causes the oil passage valve (18) to block the second oil passage (14) and the oil passage check valve (17) to open the first oil passage (13). The hydraulic oil in the first pressurizing chamber (11) enters the second pressurizing chamber (12) through the first oil passage (13). The lower piston (8) During the upward movement, the inner piston (10) moves upward, compressing the second pressurizing chamber (12). The oil pressure in the second pressurizing chamber (12) causes the oil inlet valve (19) to open the oil inlet channel (15). The hydraulic oil in the second pressurizing chamber (12) enters the pressure chamber (7) through the oil inlet channel (15). When the piston rod (6) needs to move downward, the foot pedal assembly drives the lower piston (8) to move upward until the inner piston (10) pushes the oil inlet valve (19) to open the oil inlet channel (15) and the return oil check valve (20) to open the return oil channel (16). The hydraulic oil in the pressure chamber (7) returns to the oil storage chamber (5) through the oil inlet channel (15), the second pressurizing chamber (12), and the return oil channel (16).

2. An actuator cylinder for ease of operation according to claim 1 wherein: The valve body (3) is provided with a valve core hole (21). The side wall of the valve core hole (21) is provided with an oil inlet hole (22) and an oil outlet hole (23) that are connected to the return oil channel (16) and are arranged opposite to each other. An adjusting valve core (24) is slidably arranged in the valve core hole (21) along the axial direction. The valve core hole (21) on one side of the adjusting valve core (24) is connected to the oil storage chamber (5), and the valve core hole (21) on the other side is connected to the oil inlet channel (15). The adjusting valve core (24) includes a frustum section (24a) that is arranged opposite to the oil inlet hole (22). The diameter of the frustum section (24a) gradually increases from the side of the valve core hole (21) connected to the oil storage chamber (5) to the other side.

3. An easy-to-operate oil cylinder according to claim 2, characterized in that: The valve core hole (21) is provided with a spring (25) that makes the regulating valve core (24) move toward the oil inlet channel (15) with elasticity. The regulating valve core (24) also includes a small cylindrical section (24b) with the same diameter as the minimum diameter of the frustum section (24a) and a large cylindrical section (24c) with the same diameter as the maximum diameter of the frustum section (24a). The small cylindrical section (24b) is connected to the minimum diameter of the frustum section (24a), and the large cylindrical section (24c) is connected to the maximum diameter of the frustum section (24a). The regulating valve core (24) is provided with a convex ring (24d) and a convex ring (24e) that abut against and seal against the side wall of the valve core hole (21). The convex ring (24d) is located on the side of the small cylindrical section (24b) away from the frustum section (24a), and the convex ring (24e) is located on the side of the large cylindrical section (24c) away from the frustum section (24a).

4. The cylinder of claim 1, wherein: The oil passage valve (18) includes an oil passage valve core (18a) for blocking and opening the second oil passage (14) and a second spring (18b) that springs the oil passage valve core (18a) back to the oil storage chamber (5). The valve body (3) is provided with a mounting hole (26). A pressure reducing valve core (27) is slidably disposed in the mounting hole (26). The mounting hole (26) on one side of the pressure reducing valve core (27) is connected to the pressure chamber (7). The end of the pressure reducing valve core (27) away from the pressure chamber (7) is connected to the oil passage valve core (18a). Under heavy load, the pressure reducing valve core (27) pushes the oil passage valve core (18a) to open the second oil passage (14).

5. The easy-to-operate hydraulic cylinder according to claim 4, characterized in that: The valve body (3) is provided with an installation sleeve (28), and a push shaft (29) is slidably provided inside the installation sleeve (28) between the pressure reducing valve core (27) and the oil passing valve core (18a). The push shaft (29) is fitted with a spring three (30) that has elastic force to move the push shaft (29) toward the pressure reducing valve core (27).

6. An easy-to-operate oil cylinder according to claim 4, characterized in that: The oil valve core (18a) is provided with an oil unloading channel (47) that connects the oil storage chamber (5) and the pressurization chamber (11).

7. An easy-to-operate oil cylinder according to claim 1, characterized in that: The inlet valve (19) includes an inlet valve core (19a) for blocking and opening the inlet passage (15) and a spring four (19b) that springs back the inlet valve core (19a) to the pressure chamber two (12). The end of the inlet valve core (19a) near the pressure chamber two (12) extends out of the valve body (3). The return check valve (20) includes a return valve core (20a) for blocking and opening the return passage (16) and a spring that springs back the return valve core (20a) to the pressure chamber two (12). (12) The spring five (20b) resets on one side, and the end of the return valve core (20a) near the pressure chamber two (12) extends out of the valve body (3); the elastic force of the spring four (19b) is much smaller than that of the spring five (20b); when the inner piston (10) moves upward and pushes the inlet valve core (19a) and the return valve core (20a) into the valve body (3), the inlet valve core (19a) opens the inlet channel (15), and the return valve core (20a) opens the return channel (16).

8. The cylinder of claim 1, wherein: The lower piston (8) is a hollow cylindrical shape with an upward-facing opening. A mounting base (31) is provided inside the lower piston (8). The mounting base (31) includes a base plate (31a) and a sleeve portion (31b) located above the base plate (31a). The inner end face of the lower piston (8) is recessed to form a groove (32). An oil passage hole (33) is provided on the base plate (31a) connecting the pressure chamber (11) and the groove (32). The upper end of the sleeve portion (31b) is fixedly connected to the lower end of the inner piston (10), and the upper end of the sleeve portion (31b) is positioned inside the inner piston (10). The mounting base (31) is provided with a through hole (34) connecting the groove (32) and the pressure chamber (12). The oil passage hole (33), the groove (32) and the through hole (34) form the oil passage channel (13). The oil passage check valve (17) is set in the through hole (34). A spring six (35) is provided between the inner piston (10) and the base plate (31a) and is fitted outside the fitting part (31b). When the inner piston (10) pushes the oil inlet valve (19) and the oil return check valve (20), the lower end of the connector (9) abuts against the spring six (35).

9. An easy-to-operate oil cylinder according to claim 8, characterized in that: The connector (9) is fitted with a spring seven (36), the upper end of which abuts against the valve body (3) and the lower end of which abuts against the base plate (31a).

10. The cylinder of claim 1, wherein: A base frame (37) is installed below the base (1). The foot pedal assembly includes a hinge seat 1 (38) with its lower end hinged to the base frame (37). A hinge seat 2 (39) is hinged to the upper end of the hinge seat 1 (38). One end of the hinge seat 2 (39) is hinged to the lower piston (8), and the other end is hinged to one end of the foot pedal (40). A torsion spring (41) with elastic force is fitted on the hinge shaft between the hinge seat 2 (39) and the foot pedal (40) to make the foot pedal (40) rotate upward. The end of the foot pedal (40) that is hinged to the hinge seat 2 (39) is provided with a limiting plate (42) that abuts against and limits the hinge seat 2 (39).

Images