阅读说明：本技术 一种具有全行程手动调节、限位和锁定功能的气动执行器 (Pneumatic actuator with full-stroke manual adjusting, limiting and locking functions ) 是由 吴伟国 汤俊杰 于 2020-06-23 设计创作，主要内容包括：本发明提供了一种具有全行程手动调节、限位和锁定功能的气动执行器,包括执行器缸体、齿轮传动轴、活塞、端盖、弹簧、封盖、调节装置和指示器,执行器缸体分为行程段和限位段,齿轮传动轴设置在执行器缸体内部,活塞包括气动活塞和限位活塞,端盖安装在执行器缸体的行程段远端,端盖内侧面与活塞盘一远端面之间通过多组弹簧连接,封盖安装在执行器缸体的限位段远端,封盖中心处固定设有轴承,轴承的内环外侧固定连接有旋转套杆,调节装置包括螺纹限位杆和手动转轮,指示器固定套接在螺纹套杆远端。总之,本发明具有结构新颖、调节方便、安全性高等优点。(The invention provides a pneumatic actuator with full-stroke manual adjustment, limiting and locking functions, which comprises an actuator cylinder body, a gear transmission shaft, a piston, an end cover, a spring, a sealing cover, an adjusting device and an indicator, wherein the actuator cylinder body is divided into a stroke section and a limiting section, the gear transmission shaft is arranged in the actuator cylinder body, the piston comprises the pneumatic piston and the limiting piston, the end cover is arranged at the far end of the stroke section of the actuator cylinder body, the inner side surface of the end cover is connected with the far end surface of a piston disc through a plurality of groups of springs, the sealing cover is arranged at the far end of the limiting section of the actuator cylinder body, a bearing is fixedly arranged at the center of the sealing cover, a rotary sleeve rod is fixedly connected to the outer side of an inner ring of the bearing, the adjusting device comprises. In a word, the invention has the advantages of novel structure, convenient adjustment, high safety and the like.)

1. A pneumatic actuator with full-stroke manual adjustment, limiting and locking functions is characterized by mainly comprising an actuator cylinder body (1), a gear transmission shaft (2), a piston (3), an end cover (4), a spring (5), a sealing cover (6), an adjusting device (7) and an indicator (8),

the actuator cylinder body (1) is a cylindrical cylinder body with a hollow interior, the actuator cylinder body (1) is divided into a stroke section (11) for the movement of the piston (3) and a limit section (12) for limiting the stroke of the piston (3) from left to right, the upper end surface and the lower end surface of the actuator cylinder body (1) are respectively and symmetrically provided with a shaft hole (113) for installing the gear transmission shaft (2),

the upper end and the lower end of the gear transmission shaft (2) respectively penetrate through the two shaft holes (113) and are arranged in the actuator cylinder body (1), racks (21) are uniformly arranged on the side surface of the gear transmission shaft (2), the upper end of the gear transmission shaft (2) is connected with an angle indicator (22) for indicating the rotation angle of the gear transmission shaft (2),

the piston (3) is divided into a pneumatic piston (31) arranged in the far end of the stroke section (11) and a limit piston (32) arranged in the stroke section (11) and close to the limit section (12), the pneumatic piston (31) is meshed with a rack (21) on the gear transmission shaft (2), a piston guide plate I (311) is arranged on the contact surface of the pneumatic piston (31) and the inner wall of the actuator cylinder body (1), the far end of the pneumatic piston (31) is connected with a piston disc I (312), the limit piston (32) is meshed with the rack (21) on the gear transmission shaft (2), a piston guide plate II (321) is arranged on the contact surface of the limit piston (32) and the inner wall of the actuator cylinder body (1), and the far end of the limit piston (32) is connected with a piston disc II (322),

the end cover (4) is fixedly and hermetically arranged at the far end of the stroke section (11) of the actuator cylinder body (1), the inner side surface of the end cover (4) is connected with the far end surface of the piston disc I (312) through a plurality of groups of springs (5),

the sealing cover (6) is fixedly and hermetically arranged at the far end of the limiting section (12) of the actuator cylinder body (1), a bearing (61) is fixedly arranged at the center of the sealing cover (6), a rotating loop bar (62) for rotating the bearing is fixedly connected to the outer side of an inner ring of the bearing (61), the rotating loop bar (62) comprises a rotating nut (621) close to the end of the bearing (61) and a threaded loop bar (622) fixedly connected to the far end of the rotating nut (621), and the inner surface and the outer surface of the rotating nut are both provided with threads,

the adjusting device (7) comprises a thread limiting rod (71) sleeved in the rotating sleeve rod (62) and a manual rotating wheel (72) sleeved on the rotating nut (621), one end, extending into the limiting section (12), of the thread limiting rod (71) is fixedly provided with a limiting device (711), the position of the limiting device (711) is adjusted by rotating the manual rotating wheel (72) to limit the stroke of the limiting piston (32),

the indicator (8) is fixedly sleeved at the far end of the threaded sleeve rod (622), the indicator (8) is hollow, and an indicating window (81) used for observing the position of the threaded limiting rod (71) is formed in the side wall of the indicator (8).

2. The pneumatic actuator with the full-stroke manual adjusting, limiting and locking functions as claimed in claim 1, wherein an air port A (111) and an air port B (112) are formed in the front side face of the actuator cylinder (1) in a penetrating mode, a sealing portion between the pneumatic piston (31) and the limiting piston (32) is communicated with the air port A (111), compressed air is filled through the air port A (111) to push the pneumatic piston (31) and the limiting piston (32) to move, and the sealing portion between the pneumatic piston (31) and the end cover (4), the sealing portion between the limiting piston (32) and the sealing cover (6) are respectively communicated with the air port B (112) and used for exhausting air squeezed when the pneumatic piston (31) and the limiting piston (32) move.

3. The pneumatic actuator with full-stroke manual adjusting, limiting and locking functions as claimed in claim 1, characterized in that the end cover (4) and the sealing cover (6) are both provided with a pressure relief valve (9) for discharging compressed gas in the actuator cylinder (1).

4. Pneumatic actuator with full stroke manual adjustment, limit and lock function according to claim 1, characterized by that, the angle indicator (22) on the upper end of the gear transmission shaft (2) and the lower end of the gear transmission shaft (2) are sealed with the actuator cylinder (1).

5. A pneumatic actuator with full stroke manual adjustment, limitation and locking function according to claim 1, characterized in that the outside of the bearing (61) is provided with a locking hole (611), and the locking hole (611) limits the rotation of the bearing (61) by inserting a locking bolt (612).

6. The pneumatic actuator with full stroke manual adjustment, limit and locking function according to claim 1 is characterized in that, stroke scales are arranged on two sides of the indication window (81), and one end of the threaded limit rod (71) positioned at the indicator (8) is provided with a pointer (712) for pointing to the stroke scales.

7. A pneumatic actuator with full stroke manual adjustment, limitation and locking function according to claim 1, characterized in that the end of the threaded limiting rod (71) at the indicator (8) is provided with a pointer (712) for pointing to the stroke scale.

Technical Field

The invention belongs to the technical field of actuators, and particularly relates to a pneumatic actuator with full-stroke manual adjustment, limiting and locking functions.

Background

The pneumatic actuator is an actuating device for opening and closing or regulating a valve by air pressure, is also called a pneumatic actuating mechanism or a pneumatic device, but is generally called a pneumatic head. Pneumatic actuators are sometimes also equipped with certain auxiliary devices. Commonly used valve positioners and hand wheel mechanisms. The valve positioner is used for improving the performance of the actuator by utilizing a feedback principle, so that the actuator can realize accurate positioning according to a control signal of the controller. The hand wheel mechanism is used for directly operating the control valve to maintain normal production when the control system has no power supply, no air supply, no output of the controller or failure of the actuating mechanism.

The types and configurations of the adjustment mechanisms of the pneumatic actuators are substantially the same, mainly the actuators are different. Therefore, the pneumatic actuator is divided into an actuator and a regulating valve in the description. The pneumatic actuator consists of an actuating mechanism and a regulating valve. And generating corresponding thrust to push the regulating valve to act according to the magnitude of the control signal. The regulating valve is a regulating part of the pneumatic actuator, and generates certain displacement or rotation angle under the action of thrust of the actuating mechanism, so that the flow of fluid is directly regulated.

The advantages and disadvantages of the pneumatic actuator include: (1) the load is large, and the high-torque output application can be adapted; (2) the action is rapid and the response is rapid; (3) the adaptability of the working environment is good, and the device is more superior to hydraulic, electronic and electric control in the severe working environments such as inflammable, explosive, dusty, strong magnetic, radiation and vibration; (4) the motor is easily damaged when the stroke is blocked or the valve rod is tied. (5) The control precision is lower, and the pneumatic actuator can not return to the preset position after the air supply is cut off.

Most of the existing pneumatic actuators are conventional pneumatic actuators, the stroke range of the existing pneumatic actuators cannot be adjusted in a large range, and the existing pneumatic actuators are difficult to return to a preset position manually after a gas source is cut off, so that the pneumatic actuator with full-stroke manual adjustment, limiting and locking functions is designed.

Disclosure of Invention

In view of the above problems, the present invention provides a pneumatic actuator with full-stroke manual adjustment, limiting and locking functions.

The technical scheme of the invention is as follows: a pneumatic actuator with full-stroke manual regulation, limiting and locking functions mainly comprises an actuator cylinder body, a gear transmission shaft, a piston, an end cover, a spring, a sealing cover, a regulating device and an indicator,

the actuator cylinder body is a cylindrical cylinder body with a hollow interior, the actuator cylinder body is divided into a stroke section for the motion of the piston and a limit section for limiting the stroke of the piston from left to right, the upper end surface and the lower end surface of the actuator cylinder body are respectively and symmetrically provided with shaft holes for mounting the gear transmission shaft,

the upper end and the lower end of the gear transmission shaft respectively penetrate through the two shaft holes and are arranged in the actuator cylinder body, racks are uniformly arranged on the side surface of the gear transmission shaft, the upper end of the gear transmission shaft is connected with an angle indicator for indicating the rotation angle of the gear transmission shaft,

the piston is divided into a pneumatic piston arranged in the far end of the stroke section and a limit piston arranged in the stroke section and close to the limit section, the pneumatic piston is meshed with a rack on the gear transmission shaft, a piston guide plate I is arranged on the contact surface of the pneumatic piston and the inner wall of the cylinder body of the actuator, the far end of the pneumatic piston is connected with a piston disc I, the limit piston is meshed with the rack on the gear transmission shaft, a piston guide plate II is arranged on the contact surface of the limit piston and the inner wall of the cylinder body of the actuator, and the far end of the limit piston is connected with a piston disc II,

the end cover is fixedly and hermetically arranged at the far end of the stroke section of the actuator cylinder body, the inner side surface of the end cover is connected with the far end surface of the piston disc through a plurality of groups of springs,

the sealing cover is fixedly and hermetically arranged at the far end of the limiting section of the actuator cylinder body, a bearing is fixedly arranged at the center of the sealing cover, a rotating loop bar for rotating the bearing is fixedly connected to the outer side of an inner ring of the bearing, the rotating loop bar comprises a rotating nut close to the end of the bearing and a threaded loop bar which is fixedly connected to the far end of the rotating nut and is provided with threads on the inner surface and the outer surface,

the adjusting device comprises a threaded limiting rod sleeved in the rotating sleeve rod and a manual rotating wheel sleeved on the rotating nut, a limiting stopper is fixedly arranged at one end of the threaded limiting rod extending into the limiting section, the position of the limiting stopper is adjusted by rotating the manual rotating wheel to limit the stroke of the limiting piston,

the indicator is fixedly sleeved at the far end of the threaded sleeve rod, the indicator is hollow, and an indicating window for observing the position of the threaded limiting rod is arranged on the side wall of the indicator.

Furthermore, an air port A and an air port B are arranged on the front side face of the actuator cylinder body in a penetrating mode, the middle sealing portion of the pneumatic piston and the limiting piston is communicated with the air port A, compressed air is filled through the air port A to push the pneumatic piston and the limiting piston to move, the middle sealing portion of the pneumatic piston and the end cover, the middle sealing portion of the limiting piston and the sealing cover are respectively communicated with the air port B and used for discharging air extruded when the pneumatic piston and the limiting piston move, and the operation of the pneumatic actuator is controlled through the air inlet and the air outlet of the air port A and the air port B.

Furthermore, lubricating grooves are uniformly formed in the contact surfaces of the inner side walls of the piston guide plate I and the piston guide plate II and the actuator cylinder body respectively, lubricating oil is pre-filled in the lubricating grooves, the lubricating oil can reduce friction loss between the piston guide plate I and the actuator cylinder body and the inner wall of the actuator cylinder body, heat generated by friction can be absorbed, and thermal stress deformation of the piston guide plate I, the piston guide plate II or the actuator cylinder body caused by high temperature generated by friction is avoided.

Further, all be equipped with the relief valve that is used for discharging compressed gas in the executor cylinder body on end cover and the closing cap, the inside compressed air of executor cylinder body can cause the hindrance to manual operation when utilizing the runner to adjust pneumatic actuator stroke or dismantle maintenance pneumatic actuator, and the relief valve can operate after the evacuation of compressed air in the executor cylinder body, and is safe convenient.

Furthermore, the angle indicator at the upper end of the gear transmission shaft and the lower end of the gear transmission shaft are both sealed with the actuator cylinder body, so that pressure leakage caused by untight sealing is avoided, and errors are generated in operation of the pneumatic actuator.

Furthermore, a locking hole is formed in the outer side of the bearing, the locking hole limits the rotation of the bearing by inserting a locking bolt, the bearing is locked by the locking bolt after the stroke limit of the pneumatic actuator is adjusted, and the phenomenon that the bearing rotates in the working process of the pneumatic actuator to cause stroke limit deviation or failure is avoided.

Furthermore, stroke scales are arranged on two sides of the indication window, a pointer used for pointing to the stroke scales is arranged at one end, located on the indicator, of the threaded limiting rod, the pointer can accurately indicate the position of the threaded limiting rod, and the thread limiting rod is suitable for accurate limiting adjustment.

The working method of the invention comprises the following steps:

assembling an adjusting device: the method comprises the steps that a limiting device extends into a limiting section of an actuator cylinder body, the far end of a threaded limiting rod is screwed into a rotary loop bar, a manual rotating wheel is sleeved on the outer side of a rotary nut of the rotary loop bar, an indicator is rotatably sleeved on the far end of the threaded loop bar of the rotary loop bar, the manual rotating wheel is rotated to enable the far end of the threaded limiting rod to rotate and move to the farthest end in the indicator, a far-end pointer of the threaded adjusting rod is observed through an indicating window of the indicator and indicates the stroke scale zero scale positions on two sides of the indicating window, and a locking bolt is inserted into a locking hole to lock the rotating angle of a bearing;

and (4) normal operation: when the pneumatic actuator normally works, the adjusting device does not need to be rotated, compressed air enters the actuator cylinder body through the air port A, the pneumatic piston and the limiting piston are extruded outwards, the pneumatic piston and the limiting piston drive the gear transmission shaft to rotate in the movement process, so that external load is driven to do work, the travel of the pneumatic piston and the limiting piston is the maximum travel, and the limiter does not participate in the work;

limiting and relieving the stroke: when the stroke range of the pneumatic actuator needs to be limited, the locking bolt of the locking hole is taken out firstly, the manual rotating wheel is rotated to enable the threaded limiting rod to move towards the inside of the actuator cylinder body, the stroke scale of the indicating window is observed, when the pointer of the threaded limiting rod indicates the required limited stroke range, the manual rotating wheel is stopped to rotate, the locking bolt is inserted into the locking hole locking bearing, the pneumatic actuator is started, when the pneumatic piston and the limiting piston are extruded outwards by compressed air, the piston disc II of the limiting piston is blocked by the limiting stopper when moving to the position of the limiting stopper and cannot move continuously, the rotation of the gear transmission shaft is stopped randomly, the stroke range limitation of the pneumatic actuator is realized, and the manual rotating wheel is rotated to enable the pointer at the far end of the threaded limiting rod to indicate the stroke scale zero scale positions at the two sides of the indicating window, namely the stroke range limitation of the pneumatic actuator is.

The invention has the beneficial effects that: the invention provides a pneumatic actuator with full-stroke manual regulation, limiting and locking functions, which is particularly suitable for equipment needing to regulate the stroke range of the pneumatic actuator, wherein a regulating device is arranged at the side end of a cylinder body of the actuator, the stroke range limitation of the pneumatic actuator and the manual regulation of the rotating angle of the pneumatic actuator can be realized by rotating a manual rotating wheel, the pneumatic actuator is convenient and labor-saving, the limiting device is arranged in a limiting section, the limiting piston is limited by the position of the limiting device, the stroke limiting function of the pneumatic actuator is realized, an indicator is arranged at the far end of the regulating device, the stroke limiting range of the pneumatic actuator can be known by observing the position of a threaded limiting rod in an indicating window, and a lubricating groove filled with lubricating oil is arranged on a guide plate of the piston, so that the friction loss between a first piston guide plate, a second piston guide plate and the inner wall of the cylinder body of the actuator can be reduced, and the heat generated by friction can be absorbed, so that the high temperature generated by friction is prevented from causing thermal stress deformation to the piston guide plate I, the piston guide plate II or the actuator cylinder body. In a word, the invention has the advantages of novel structure, convenient adjustment, high safety and the like.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic longitudinal cross-section of the present invention;

FIG. 3 is a schematic view of an exploded structure of the present invention;

FIG. 4 is a schematic view of a rotary shank configuration of the present invention;

fig. 5 is a schematic view of the indicator structure of the present invention.

Wherein, 1-actuator cylinder, 11-stroke section, 111-air port A, 112-air port B, 113-shaft hole, 12-limit section, 2-gear transmission shaft, 21-rack, 22-angle indicator, 3-piston, 31-pneumatic piston, 311-piston guide plate I, 312-piston disc I, 32-limit piston, 321-piston guide plate II, 322-piston disc II, 33-lubrication groove, 4-end cover, 5-spring, 6-sealing cover, 61-bearing, 611-locking hole, 612-locking bolt, 62-rotating sleeve rod, 621-rotating nut, 622-thread sleeve rod, 7-adjusting device, 71-thread limit rod, 711-limit device, 712-pointer, 72-manual rotating wheel, 8-indicator, 81-indication window, 9-relief valve.

Detailed Description

For the understanding of the technical solution of the present invention, the following description is further illustrated with reference to fig. 1 to 5 and specific examples, which are not intended to limit the scope of the present invention.

As shown in figures 1-3, a pneumatic actuator with full-stroke manual adjustment, limit and locking functions mainly comprises an actuator cylinder body 1, a gear transmission shaft 2, a piston 3, an end cover 4, a spring 5, a sealing cover 6, an adjusting device 7 and an indicator 8,

the actuator cylinder body 1 is a cylindrical cylinder body with a hollow interior, the actuator cylinder body 1 is divided into a stroke section 11 for the movement of the piston 3 and a limit section 12 for limiting the stroke of the piston 3 from left to right, the upper end surface and the lower end surface of the actuator cylinder body 1 are respectively and symmetrically provided with a shaft hole 113 for installing the gear transmission shaft 2,

the upper end and the lower end of the gear transmission shaft 2 respectively penetrate through the two shaft holes 113 and are arranged inside the actuator cylinder body 1, the side surface of the gear transmission shaft 2 is uniformly provided with a rack 21, the upper end of the gear transmission shaft 2 is connected with an angle indicator 22 for indicating the rotation angle of the gear transmission shaft 2, the angle indicator 22 at the upper end of the gear transmission shaft 2 and the lower end of the gear transmission shaft 2 are both sealed with the actuator cylinder body 1,

the piston 3 is divided into a pneumatic piston 31 arranged in the far end of the stroke section 11 and a limit piston 32 arranged in the stroke section 11 and close to the limit section 12, the pneumatic piston 31 is meshed with the rack 21 on the gear transmission shaft 2, the contact surface of the pneumatic piston 31 and the inner wall of the actuator cylinder body 1 is provided with a piston guide plate I311, the far end of the pneumatic piston 31 is connected with a piston disc I312, the limit piston 32 is meshed with the rack 21 on the gear transmission shaft 2, the contact surface of the limit piston 32 and the inner wall of the actuator cylinder body 1 is provided with a piston guide plate II 321, the far end of the limit piston 32 is connected with a piston disc II 322,

the contact surfaces of the first piston guide plate 311, the second piston guide plate 321 and the inner side wall of the actuator cylinder 1 are respectively and uniformly provided with a lubricating groove 33, the lubricating grooves 33 are pre-filled with lubricating oil,

an air port A111 and an air port B112 penetrate through the front side surface of the actuator cylinder 1, the middle sealing parts of the pneumatic piston 31 and the limiting piston 32 are communicated with the air port A111, compressed air is filled through the air port A111 to push the pneumatic piston 31 and the limiting piston 32 to move, the middle sealing parts of the pneumatic piston 31 and the end cover 4 and the middle sealing parts of the limiting piston 32 and the sealing cover 6 are respectively communicated with the air port B112 and used for discharging air extruded when the pneumatic piston 31 and the limiting piston 32 move,

the end cover 4 is fixedly and hermetically arranged at the far end of the stroke section 11 of the actuator cylinder body 1, the inner side surface of the end cover 4 is connected with the far end surface of the first piston disc 312 through a plurality of groups of springs 5,

the cover 6 is fixedly and closely installed at the far end of the limiting section 12 of the actuator cylinder 1, a bearing 61 is fixedly arranged at the center of the cover 6, a rotating sleeve rod 62 for rotating the bearing is fixedly connected to the outer side of the inner ring of the bearing 61, as shown in fig. 4, the rotating sleeve rod 62 comprises a rotating nut 621 close to the end of the bearing 61 and a threaded sleeve rod 622 fixedly connected to the far end of the rotating nut 621, the inner side and the outer side of the threaded sleeve rod 622 are both provided with threads, a locking hole 611 is arranged at the outer side of the bearing 61, the locking hole 611 limits the rotation of the bearing 61 by inserting a,

the end cover 4 and the sealing cover 6 are both provided with a pressure release valve 9 for discharging compressed gas in the actuator cylinder body 1,

the adjusting device 7 comprises a thread limiting rod 71 sleeved in the rotary sleeve rod 62 and a manual rotating wheel 72 sleeved on the rotary nut 621, wherein one end of the thread limiting rod 71 extending into the limiting section 12 is fixedly provided with a limiter 711, the position of the limiter 711 is adjusted by rotating the manual rotating wheel 72 to limit the stroke of the limiting piston 32, the upper end and the lower end of the limiter 711 are respectively provided with a rotation preventing rod 7111, the upper side wall and the lower side wall of the piston disc II 322 are provided with a sliding groove 3222 for preventing the rotation preventing rod 7111 from sliding,

indicator 8 is fixed to be cup jointed at the distal end of screw sleeve pole 622, and indicator 8 is inside hollow, and is equipped with the instruction window 81 that is used for observing screw thread gag lever post 71 position on the indicator 8 lateral wall, as shown in fig. 5, indicates window 81 both sides and is equipped with the stroke scale, and the one end that screw thread gag lever post 71 is located indicator 8 is equipped with pointer 712 that is used for pointing to the stroke scale.

The assembling and working method of the embodiment comprises the following steps:

assembling an adjusting device: the stopper 711 is inserted into the limiting section 12 of the actuator cylinder 1, the far end of the threaded limiting rod 71 is screwed into the rotating sleeve rod 62, the manual rotating wheel 72 is sleeved outside the rotating nut 621 of the rotating sleeve rod 62, the indicator 8 is rotatably sleeved at the far end of the threaded sleeve rod 622 of the rotating sleeve rod 62, the manual rotating wheel 72 is rotated to enable the far end of the threaded limiting rod 71 to rotate and move to the farthest end inside the indicator 8, the far end pointer 712 of the threaded adjusting rod 71 is observed through the indicating window 81 of the indicator 8 and indicates the stroke scale zero scales on two sides of the indicating window 81, and the locking bolt 612 is inserted into the locking hole 611 to lock the rotating angle of the bearing 61;

and (4) normal operation: when the pneumatic actuator normally works, the adjusting device does not need to be rotated, compressed air enters the actuator cylinder body 1 through the air port A, the pneumatic piston 31 and the limiting piston 32 are extruded outwards, the pneumatic piston 31 and the limiting piston 32 drive the gear transmission shaft 2 to rotate in the movement process, so that external load is driven to do work, the stroke of the pneumatic piston 31 and the limiting piston 32 is the maximum stroke, and the limiter 711 does not participate in the work;

limiting and relieving the stroke: when the stroke range of the pneumatic actuator needs to be limited, the locking bolt 612 of the locking hole 611 is taken out firstly, the manual rotating wheel 72 is rotated to enable the threaded limiting rod 71 to move towards the inside of the actuator cylinder body 1, the stroke scale of the indicating window 81 is observed, when the pointer 712 of the threaded limiting rod 71 indicates the required limited stroke range, the manual rotating wheel 72 is stopped rotating, the locking bolt 612 is inserted into the locking hole 611 to lock the bearing 61, the pneumatic actuator is started, when the compressed air presses the pneumatic piston 31 and the limiting piston 32 outwards to move, the piston disc II 322 of the limiting piston 32 is blocked by the limiter 711 when moving to the position of the limiter 711, the movement cannot be continued, the rotation of the gear transmission shaft 2 is also stopped at random, the stroke range limitation of the pneumatic actuator is realized, the pointer 712 at the far end of the threaded limiting rod 71 indicates the stroke scale zero scale at two sides of the indicating window 81 by rotating the manual rotating wheel 72, i.e., to remove the travel range restriction of the pneumatic actuator.