Pneumatic clamping jaw

Abstract

The invention relates to the technical field of grabbing equipment, in particular to a pneumatic clamping jaw which comprises an air cylinder body and a piston rod, a piston cavity is formed in the air cylinder body in the axial direction of the air cylinder body, and an isolation base is arranged in the piston cavity in the circumferential direction of the piston cavity; the first end of the piston rod hermetically and slidably penetrates through the isolation seat, and the second end hermetically and slidably penetrates out of the cylinder body; a piston arranged in the piston cavity in a sealing and sliding manner is fixed on the piston rod; an air inlet cavity is formed between the piston and the isolation seat, an air outlet cavity is formed between the piston and the bottom of the piston cavity, and an air inlet communicated with the air inlet cavity and an air outlet communicated with the air outlet cavity are formed in the air cylinder body; the piston rod is in driving connection with the two clamping fingers arranged on the cylinder body in a sliding manner and is used for driving the two clamping fingers to open and close; a sealing cavity communicated with the piston cavity is formed in the top of the piston cavity, a sensor is arranged in the sealing cavity, and the abrasion degree of the clamping fingers is judged by detecting the distance between the piston rod and the sensor, so that the pneumatic clamping jaw can automatically monitor the abrasion degree of the clamping fingers.

Description

Technical Field

[0001] The present invention relates to the technical field of grasping devices, and particularly to a pneumatic gripper. Background Art

[0002] A pneumatic gripper is an actuator that uses compressed air as a power source to pick up or grasp workpieces. Its core function is to replace manual grasping, improve production efficiency and safety, and is widely used in automated production lines, machining, warehousing and logistics and other fields.

[0003] At present, in areas where the operating environment is relatively frequent, the two fingers at the end of the pneumatic gripper need to open and close back and forth. However, since the fingers need to continuously contact the product, the clamping surfaces of the fingers are continuously worn, resulting in an increase in the clamping gap between the fingers and the product, and further resulting in a condition where the product cannot be clamped tightly by the fingers and the product drops and is damaged.

[0004] In summary, the existing pneumatic grippers cannot automatically monitor the wear degree of the fingers. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, one of the purposes of the present invention is to provide a pneumatic gripper, aiming to solve the technical problem that the existing pneumatic gripper cannot automatically monitor the wear degree of its fingers.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A pneumatic gripper includes a cylinder body, a piston rod, a piston and two fingers. A piston chamber is axially arranged in the cylinder body, and a partition seat is hermetically arranged circumferentially in the piston chamber; the first end of the piston rod axially and hermetically slides through the partition seat along the cylinder body, and the second end of the piston rod axially and hermetically slides out of the cylinder body; the piston is fixed on the piston rod, and the piston is hermetically slidably arranged in the piston chamber, and the piston is located between the partition seat and the bottom of the piston chamber; an intake chamber is formed between the piston and the partition seat, and an exhaust chamber is formed between the piston and the bottom of the piston chamber. An intake port communicating with the intake chamber and an exhaust port communicating with the exhaust chamber are arranged on the cylinder body; the second end of the piston rod is drivingly connected to the two fingers slidably arranged on the cylinder body to drive the opening and closing of the two fingers; a sealing chamber hermetically communicating with the piston chamber is arranged at the top of the piston chamber, a sensor is installed in the sealing chamber, the sensor is electrically connected to a control platform arranged outside the pneumatic gripper, and the sensor judges the wear degree of the fingers by detecting the distance between the piston rod and the sensor.

[0008] Advantages of the present invention:

[0009] 1. When the pneumatic gripper of the present invention is in use, when compressed air enters the intake cavity from the intake port, the compressed air pushes the piston to drive the piston rod to move downward, driving the two fingers to move away from each other to open; when the compressed air enters the outlet cavity from the outlet port, the compressed air pushes the piston to drive the piston rod to move upward, driving the two fingers to move towards each other to close and clamp the product. Since the piston fixedly connected to the piston rod is located between the isolation seat and the bottom of the piston cavity, the upward movement stroke of the piston can be limited by the isolation seat, and the downward movement stroke of the piston can be limited by the bottom wall of the piston cavity; because the sensor is located in the sealed cavity above the piston rod, when the fingers clamp the product and the clamping surfaces of the fingers are not worn, the distance between the top end of the piston rod and the sensor is set as H1; when the fingers clamp the product and the clamping surfaces of the fingers clamping the product are worn, the distance between the top end of the piston rod and the sensor is set as H2, and the wear amount of the clamping surface of the fingers clamping the product is △H, △H = H1 - H2. When the wear amount of the clamping surface of the fingers clamping the product is greater than the preset threshold, the △H value will show an abnormality on the control platform. At this time, the control platform will remind the operator to replace the fingers, achieving full utilization of the usage rate of the fingers and avoiding product dropping due to the fingers not clamping the product tightly.

[0010] 2. Since the sensor is located in the sealed cavity communicating with the top of the piston cavity, it is avoided that the sensor is fixed on the fingers, thus avoiding fatigue failure of the sensor due to the frequent opening and closing of the fingers; in addition, since the sensor is in the sealed cavity, it is not easily affected by environmental factors (such as dust, oil), and even when the pneumatic gripper operates in a humid and high-temperature environment, the sensor is not easily damaged.

[0011] 3. Since the sensor is not fixed on the fingers, it will not affect the clamping stiffness of the fingers.

[0012] Furthermore, the pneumatic gripper of the present invention further includes a link mechanism and two finger mounting seats. A guide rail is provided at the bottom of the cylinder block, the slide rail extends along the direction perpendicular to the axis of the cylinder block, the finger mounting seats are slidably arranged on the slide rail along the extension direction of the slide rail, the piston rod is drivingly connected to the two finger mounting seats through the link mechanism, the piston rod drives the link mechanism to drive the two finger mounting seats to slide towards or away from each other along the extension direction of the slide rail, and the two fingers are respectively arranged on the two finger mounting seats.

[0013] Beneficial effect: It is beneficial to the opening and closing of the two fingers.

[0014] Furthermore, a buffer pad is provided at the bottom of the outlet cavity to prevent the piston from making hard contact with the bottom wall of the outlet cavity.

[0015] Beneficial effect: Avoid the piston from making hard contact with the bottom wall of the outlet cavity during the downward movement process.

[0016] Further, the linkage mechanism includes a first rotating shaft, a second rotating shaft, a first connecting rod, and a second connecting rod. A groove communicating with the piston chamber is formed at the bottom of the cylinder block along the extension direction of the slide rail. The first rotating shaft and the second rotating shaft are respectively horizontally rotatably arranged at two ends within the groove. The extension directions of the first rotating shaft and the second rotating shaft are perpendicular to the extension direction of the slide rail. The first connecting rod and the second connecting rod are respectively sleeved on the first rotating shaft and the second rotating shaft, and two ends of the first connecting rod are respectively connected to one of the finger mounting seats and the second end of the piston rod, and two ends of the second connecting rod are respectively connected to the other finger mounting seat and the second end of the piston rod.

[0017] Beneficial effects: The linkage mechanism amplifies the driving force through the lever principle, enabling the fingers to bear a relatively large load.

[0018] Further, a chute is formed at the bottom of the slide rail along the extension direction of the slide rail. The two finger mounting seats are slidably connected to the chute. Two waist-shaped grooves are formed on the top surface of the slide rail, and the waist-shaped grooves extend along the extension direction of the slide rail. The two waist-shaped grooves are respectively used to avoid the first connecting rod and the second connecting rod.

[0019] Beneficial effects: The chute formed at the bottom of the slide rail can, to a certain extent, prevent the chute from being exposed outside, effectively avoiding the influence of dust and having better dust-proof performance.

[0020] Further, a rolling connection is provided between the chute and the finger mounting seat.

[0021] Beneficial effects: Reduce the friction between the chute and the finger mounting seat.

[0022] Further, first arc-shaped guiding grooves are formed on opposite side walls within the chute along the extension direction of the chute. Second arc-shaped guiding grooves are formed on opposite side walls of the finger mounting seat along the extension direction of the chute. Each first arc-shaped guiding groove corresponds to each second arc-shaped guiding groove. A ball is connected between the first arc-shaped guiding groove and the second arc-shaped guiding groove, and the ball is in spherical contact with the first arc-shaped guiding groove and the second arc-shaped guiding groove.

[0023] Beneficial effects: Reduce the friction between the chute and the finger mounting seat.

[0024] Further, blocking plates are provided at opposite ends of the finger mounting seat, and the blocking plates are used to prevent the balls between the first arc-shaped guiding groove and the second arc-shaped guiding groove from falling off.

[0025] Beneficial effects: Can prevent the balls between the first arc-shaped guiding groove and the second arc-shaped guiding groove from falling off.

[0026] Further, connection holes are formed in the upper surface of the finger mounting base. The first connecting rod is connected to the connection hole on one of the finger mounting bases by a ball joint, and the second connecting rod is connected to the connection hole on the other finger mounting base by a ball joint.

[0027] Beneficial effects: Under vibration or dynamic loads, the ball joint connection can absorb deviations through its own movement, avoiding stress concentration or structural damage caused by rigid connections between the first connecting rod or the second connecting rod and the finger mounting base. Additionally, the ball joint transmits force through the contact surface, with uniform force distribution, reducing local stress concentration. When the force is unbalanced, the ball joint can automatically adjust the angle to maintain stability, preventing structural jamming or failure.

[0028] Further, a disc is provided at the top end of the piston rod. The outer diameter of the disc is larger than the outer diameter of the top end of the piston rod. A cylindrical groove is formed in the upper surface of the isolation seat. The cylindrical groove is coaxial with the disc, and the inner diameter of the cylindrical groove is larger than the outer diameter of the disc.

[0029] Beneficial effects: It can increase the detection area of the probe of the sensor on the top end of the piston rod, and to a certain extent, avoid the disc occupying the space in the sealing cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a three-dimensional structural schematic diagram of the pneumatic gripper of the present invention;

[0031] Figure 2 is Figure 1 the top view of

[0032] Figure 3 is Figure 2 the sectional view taken along line A-A in

[0033] Figure 4 is Figure 3 the enlarged structural schematic diagram at B in

[0034] Figure 5 is Figure 1 the bottom view of

[0035] Figure 6 is Figure 1 the front view of

[0036] Figure 7 is a structural schematic diagram of the cylinder block involved in this embodiment;

[0037] Figure 8 is Figure 7 the bottom view of

[0038] Figure 9 is a structural schematic diagram of the connection between the piston assembly, the clamping assembly and the connecting rod mechanism involved in this embodiment;

[0039] Figure 10 This is a schematic structural view of a guide rail according to this embodiment;

[0040] Figure 11 This is a top view of a guide rail according to this embodiment;

[0041] Figure 12 This is a schematic structural view of a finger mounting seat according to this embodiment;

[0042] Figure 13 This is a left view of a finger mounting seat according to this embodiment.

[0043] Markings in each drawing:

[0044] 1. Cylinder block; 10. Piston chamber; 11. Air inlet; 12. Air outlet; 13. Groove; 14. Perforation; 140. First annular groove; 141. First sealing ring; 15. Isolation seat; 150. Second annular groove; 151. Second sealing ring; 152. Cylindrical groove; 153. Third annular groove; 154. Third sealing ring; 16. Slide rail; 160. Slide groove; 161. First arc-shaped guiding groove; 162. Waist-shaped groove; 2. Piston assembly; 20. Piston rod; 201. Disc; 21. Piston; 210. Air inlet chamber; 211. Air outlet chamber; 212. Buffer pad; 213. Fourth annular groove; 214. Fourth sealing ring; 3. Clamping assembly; 30. Finger mounting seat; 301. Second arc-shaped guiding groove; 302. Baffle plate; 303. Connecting hole; 31. Fingers; 32. Ball; 4. Link mechanism; 40. First rotating shaft; 41. Second rotating shaft; 42. First link; 43. Second link; 5. Sealing upper cover; 50. Sealing chamber; 501. Sensor; 51. Fifth sealing ring. Specific embodiments

[0045] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "width", "upper", "lower", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features between them.

[0048] Embodiment 1

[0049] Please refer to Figure 1 - Figure 13 The present invention provides a pneumatic gripper, which includes a cylinder block 1, a piston assembly 2, a clamping assembly 3, a link mechanism 4 and a sealing upper cover 5.

[0050] In this embodiment, refer to Figure 1 、 Figure 3 、 Figure 4 and Figure 6 - Figure 8, a piston chamber 10 is arranged axially along the cylinder block 1 itself. An air inlet 11 and an air outlet 12 are arranged on one side wall of the cylinder block 1, and both the air inlet 11 and the air outlet 12 communicate with the piston chamber 10. A groove 13 communicating with the piston chamber 10 is formed at the bottom of the cylinder block 1 along a direction perpendicular to the axis of the cylinder block 1; the piston chamber 10 and the groove 13 are communicated through a through hole 14 arranged on the cylinder block 1. The through hole 14 is coaxially arranged with the piston chamber 10. A first annular groove 140 is formed in the through hole 14 along its circumferential direction, and a first sealing ring 141 is fixedly installed in the first annular groove 140. In addition, a partition seat 15 is fixedly arranged in the piston chamber 10 along its circumferential direction, and the partition seat 15 and the piston chamber 10 are sealed through a second sealing ring 151. A second annular groove 150 is formed in the outer wall of the partition seat 15 along its circumferential direction, and the second sealing ring 151 is installed in the second annular groove 150. In addition, a cylindrical groove 152 is formed in the top end surface of the partition seat 15, and the cylindrical groove 152 is coaxially arranged with the piston chamber 10; a third annular groove 153 is formed in the bottom of the partition seat 15 along its circumferential direction, and a third sealing ring 154 is fixedly installed in the third annular groove 153.

[0051] In this embodiment, referring to Figure 3 , Figure 6 , Figure 10 and Figure 11 , a slide rail 16 is fixed to the bottom of the cylinder block 1. The slide rail 16 extends along a direction perpendicular to the axis of the cylinder block 1, and the extending direction of the slide rail 16 is the same as the extending direction of the above-mentioned groove 13. In addition, a chute 160 is formed in the bottom of the slide rail 16 along the extending direction of the slide rail 16. The chute 160 penetrates through the opposite ends of the slide rail 16, and first arc-shaped guiding grooves 161 are formed in the opposite side walls of the chute 160 along the extending direction of the chute 160. In addition, two kidney-shaped grooves 162 are formed in the top surface of the slide rail 16, and the kidney-shaped grooves 162 extend along the extending direction of the slide rail 16.

[0052] In this embodiment, referring to Figure 3 , Figure 4 , Figure 7 and Figure 9, the piston assembly 2 includes a piston rod 20 and a piston 21. The piston rod 20 and the piston 21 are integrally connected. The piston 21 is fixed on the piston rod 20 and is coaxially arranged with the piston rod 20. The outer diameter of the piston rod 20 is smaller than the outer diameter of the piston 21. The first end of the piston rod 20 slides axially through the above-mentioned isolation seat 15 in a sealed manner along the cylinder block 1, and is sealed between the first end of the piston rod 20 and the isolation seat 15 by the above-mentioned third sealing ring 154. The second end of the piston rod 20 slides out of the piston chamber 10 through the perforation 14 axially along the cylinder block 1 and enters the groove 13 to be connected with the connecting rod mechanism 4. The second end of the piston rod 20 is sealed with the cylinder block 1 by the above-mentioned first sealing ring 141. In addition, a disc 201 is threadedly connected to the top end of the piston rod 20. The outer diameter of the disc 201 is larger than the outer diameter of the top end of the piston rod 20. A cylindrical groove 152 is formed on the upper surface of the isolation seat 15. The cylindrical groove 152 is coaxially arranged with the disc 201. The inner diameter of the cylindrical groove 152 is larger than the outer diameter of the disc 201. The cylindrical groove 152 is mainly used to accommodate the disc 201.

[0053] Referring to Figure 3 , Figure 4 and Figure 9 , the piston 21 is arranged to slide in a sealed manner in the piston chamber 10, and the piston 21 is located between the isolation seat 15 and the bottom of the piston chamber 10. The piston 21 is sealed with the piston chamber 10 by a fourth sealing ring 214. A fourth annular groove 213 is formed on the outer peripheral wall of the piston 21, and the fourth sealing ring 214 is installed and fixed in the fourth annular groove 213. Of course, an air inlet chamber 210 is formed between the piston 21 and the isolation seat 15. The air inlet chamber 210 communicates with the air inlet 11. An air outlet chamber 211 is formed between the piston 21 and the bottom of the piston chamber 10. The air outlet chamber 211 communicates with the air outlet 12. When compressed air enters the air inlet chamber 210 from the air inlet 11, the compressed air pushes the piston 21 to drive the piston rod 20 to move downward. When compressed air enters the air outlet chamber 211 from the air outlet 12, the compressed air pushes the piston 21 to drive the piston rod 20 to move upward. In order to prevent the piston 21 from making hard contact with the bottom wall in the air outlet chamber 211, a buffer pad 212 is arranged at the bottom in the air outlet chamber 211 to protect the piston 21.

[0054] In this embodiment, referring to Figure 1 , Figure 3 - Figure 5 and Figure 10 - Figure 13, the clamping assembly 3 includes two finger mounting seats 30 and two fingers 31. Each finger 31 corresponds to each finger mounting seat 30 one by one. The two fingers 31 are respectively arranged on the two finger mounting seats 30. Each finger 31 and each finger mounting seat 30 can be detachably connected by screws, so that the replacement of the finger 31 is convenient. Among them, the finger mounting seat 30 is slidably arranged on the slide rail 16 along the extension direction of the slide rail 16, so that the two finger mounting seats 30 are both slidably connected to the chute 160. It can be seen from this that the two fingers 31 slidably arranged on the guide rail of the cylinder block 1 are respectively driven and connected to the second end of the piston rod 20 through the two finger mounting seats 30. In this way, by driving the two finger mounting seats 30 to move towards or away from each other, the opening and closing of the two fingers 31 can be driven.

[0055] In this embodiment, referring to Figure 3 , Figure 5 , Figure 9 - Figure 11 , the finger mounting seat 30 is in rolling connection with the chute 160 of the slide rail 16, so that the friction between the chute 160 and the finger mounting seat 30 can be reduced, and the process of the finger mounting seat 30 sliding along the chute 160 is smoother. Specifically, second arc-shaped guide grooves 301 are opened on the opposite side walls of the finger mounting seat 30 along the extension direction of the chute 160. Each first arc-shaped guide groove 161 corresponds to each second arc-shaped guide groove 301 one by one. A ball 32 is connected between the first arc-shaped guide groove 161 and the second arc-shaped guide groove 301. The ball 32 is in spherical contact with the first arc-shaped guide groove 161 and the second arc-shaped guide groove 301. In this way, the friction between the finger mounting seat 30 and the slide rail 16 can be greatly reduced, the opening and closing actions of the two finger mounting seats 30 respond quickly, and further the opening and closing actions of the two fingers 31 respond quickly.

[0056] In this embodiment, referring to Figure 3 and Figure 9 , blocking plates 302 are fixed at the opposite ends of the finger mounting seat 30. The blocking plates 302 are mainly used to block the balls 32 between the first arc-shaped guide groove 161 and the second arc-shaped guide groove 301 from falling off. In addition, connection holes 303 are opened on the upper surface of the finger mounting seat 30. The connection holes 303 on each finger mounting seat 30 communicate with the corresponding waist-shaped grooves 162. The connection holes 303 are mainly used for connecting the link mechanism 4.

[0057] In this embodiment, referring to Figure 3 and Figure 9, the connecting rod mechanism 4 is used to connect the two finger mounting seats 30 and the piston rod 20. That is to say, the piston rod 20 is drivingly connected to the two finger mounting seats 30 through the connecting rod mechanism 4. The piston rod 20 drives the two finger mounting seats 30 to slide towards or away from each other along the extension direction of the slide rail 16 by driving the connecting rod mechanism 4. Specifically, the connecting rod mechanism 4 includes a first rotating shaft 40, a second rotating shaft 41, a first connecting rod 42 and a second connecting rod 43. A groove 13 communicating with the piston chamber 10 is formed in the bottom of the cylinder block 1 along the extension direction of the slide rail 16. The first rotating shaft 40 and the second rotating shaft 41 are respectively horizontally rotatably arranged at both ends in the groove 13. The extension directions of the first rotating shaft 40 and the second rotating shaft 41 are perpendicular to the extension direction of the slide rail 16. The first connecting rod 42 and the second connecting rod 43 are respectively sleeved on the first rotating shaft 40 and the second rotating shaft 41. One end of the first connecting rod 42 is connected to the second end of the piston rod 20, and the other end of the first connecting rod 42 passes through a kidney-shaped groove 162 and is ball-jointed to a connection hole 303 on a finger mounting seat 30; one end of the second connecting rod 43 is connected to the second end of the piston rod 20, and the other end of the second connecting rod 43 passes through another kidney-shaped groove 162 and is ball-jointed to a connection hole 303 on the other finger mounting seat 30. It can be seen from this that the two kidney-shaped grooves 162 on the slide rail 16 are mainly used to avoid the first connecting rod 42 and the second connecting rod 43 of the connecting rod mechanism 4 respectively, and prevent the slide rail 16 from interfering with the connection of the first connecting rod 42 and the second connecting rod 43 to the two finger mounting seats 30 respectively. Since the first connecting rod 42 is ball-jointed to the connection hole 303 on one finger mounting seat 30 and the second connecting rod 43 is ball-jointed to the connection hole 303 on the other finger mounting seat 30, under vibration or dynamic load, the ball joint can absorb deviations through its own movement, avoiding stress concentration or structural damage caused by the rigid connection between the first connecting rod 42 or the second connecting rod 43 and the finger mounting seat 30; in addition, the ball head transmits force through the contact surface, and the force is evenly distributed, reducing local stress concentration. When the force is unbalanced, the ball head can automatically adjust the angle to maintain stability, avoiding jamming or failure of the connection structure between the first connecting rod 42 or the second connecting rod 43 and the finger mounting seat 30.

[0058] In this embodiment, referring to Figure 3 , the sealing upper cover 5 is fixed on the top of the cylinder block 1. The inner cavity of the sealing upper cover 5 is a sealing cavity 50 communicating with the piston chamber 10. The sealing upper cover 5 and the cylinder block 1 are sealed by a fifth sealing ring 51, so that the sealing cavity 50 and the piston chamber 10 are sealed and communicated. Among them, a sensor 501 is installed in the sealing cavity 50. The sensor 501 is electrically connected to a control platform (not shown) arranged outside the pneumatic gripper. The control platform is used to display the detection data of the sensor 501. The sensor 501 judges the wear degree of the finger 31 by detecting the distance between the piston rod 20 and the sensor 501.

[0059] The working principle of the present invention:

[0060] When the pneumatic gripper of the present invention is in use, when compressed air enters the air inlet cavity 210 from the air inlet 11, the compressed air pushes the piston 21 to drive the piston rod 20 to move downward, thereby driving the linkage mechanism 4 to drive the two finger mounting seats 30 to move away from each other and open, and further causing the two fingers 31 to open; when compressed air enters the air outlet cavity 211 from the air outlet 12, the compressed air pushes the piston 21 to drive the piston rod 20 to move upward, thereby driving the linkage mechanism 4 to drive the two finger mounting seats 30 to move toward each other and close, and further causing the two fingers 31 to close and clamp the product. Since the piston 21 fixedly connected to the piston rod 20 is located between the isolation seat 15 and the bottom of the piston cavity 10, the upward stroke of the piston 21 can be limited by the isolation seat 15, and the downward stroke of the piston 21 can be limited by the bottom wall of the piston cavity 10; because the sensor 501 is located in the sealed cavity 50 above the piston rod 20, when the fingers 31 clamp the product and the clamping surface of the fingers 31 is not worn, the distance between the top disc 201 of the piston rod 20 and the sensor 501 is set as H1; when the fingers 31 clamp the product and the clamping surface of the fingers 31 for clamping the product is worn, the distance between the top disc 201 of the piston rod 20 and the sensor 501 is set as H2, and the wear amount of the clamping surface of the fingers 31 for clamping the product is ΔH, ΔH = H1 - H2. Of course, the value of ΔH can be displayed on the control platform. When the wear amount of the clamping surface of the fingers 31 for clamping the product is greater than the preset threshold (the preset threshold is set on the control platform), the value of ΔH will be displayed abnormally on the control platform. At this time, the control platform will remind the operator to replace the fingers 31, making full use of the usage rate of the fingers 31 and avoiding the product from falling due to the fingers 31 not clamping the product tightly. That is to say, it can be understood that the pneumatic gripper of the present invention converts the change amount (ΔH) of the distance between the top disc 201 of the piston rod 20 and the sensor 501 into the wear amount of the fingers 31.

[0061] It should be noted that since the sensor 501 is located in the sealed cavity 50 communicating with the top of the piston cavity 10, the sensor 501 can be prevented from being fixed on the fingers 31, thereby avoiding the fatigue failure of the sensor 501 caused by the frequent opening and closing of the fingers 31; in addition, since the sensor 501 is in the sealed cavity 50, it is not easily affected by environmental factors (such as dust and oil). Even when the pneumatic gripper operates in a humid and high-temperature environment, the sensor 501 is not easily damaged. In addition, since the sensor 501 is not fixed on the fingers 31, it does not affect the clamping stiffness of the fingers 31.

[0062] In this embodiment, by way of example, it is assumed that the preset threshold value of the wear amount of the clamping surface of the finger 31 is 5 mm. The sensor 501 in this embodiment is a laser displacement sensor 501. When the finger 31 clamps the product and the clamping surface of the finger 31 has no wear, the distance H1 between the top disk 201 of the piston rod 20 and the laser displacement sensor 501 detected by the laser displacement sensor 501 is 10 mm; when the finger 31 clamps the product and the clamping surface of the finger 31 has wear, the distance H2 between the top disk 201 of the piston rod 20 and the sensor 501 detected by the laser displacement sensor 501 is 8 mm. At this time, the wear amount △H of the clamping surface of the finger 31 is 2 mm and is displayed on the control platform. Since △H = 2 mm is less than the preset threshold value of 5 mm, the control platform will not prompt the operator to replace the finger 31. When the finger 31 clamps the product and the clamping surface of the finger 31 has no wear, the distance H1 between the top disk 201 of the piston rod 20 and the laser displacement sensor 501 detected by the laser displacement sensor 501 is 10 mm; when the finger 31 clamps the product and the clamping surface of the finger 31 has wear, the distance H2 between the top disk 201 of the piston rod 20 and the sensor 501 detected by the laser displacement sensor 501 is 4 mm. At this time, the wear amount △H of the clamping surface of the finger 31 is 6 mm and is displayed on the control platform. Since △H = 6 mm is greater than the preset threshold value of 5 mm, the △H value will be displayed abnormally on the control platform. At this time, the control platform will remind the operator to replace the finger 31. It can be seen that the laser displacement sensor 501 in this embodiment uses the principle of laser triangulation or time of flight to measure the distance between the top of the piston rod 20 and the laser displacement sensor 501 in real time. When the clamping surface of the finger 31 wears, it will cause a change in the movement stroke of the piston rod 20, which in turn affects the position of the top of the piston rod 20. By monitoring the change amount of the distance between the laser displacement sensor 501 and the top disk 201 of the piston rod 20, the wear degree of the finger 31 can be deduced.

[0063] Embodiment 2

[0064] The difference between this embodiment and Embodiment 1 is that the type of the sensor 501 is different. The sensor 501 is a TOF sensor, that is, the TOF (Time of Flight) ranging method is used to detect the wear degree of the finger 31. By measuring the time for the optical signal to be emitted from the TOF sensor to the target object (the top disk 201 of the piston 21) and reflected back, and combining the speed of light to calculate the distance between the TOF sensor and the target object. Using this principle, the wear amount of the finger 31 can be indirectly judged by monitoring the change in the distance between the TOF sensor and the top of the piston 21. It should be noted that the working principle of the TOF sensor belongs to the prior art and will not be described here.

[0065] Embodiment 3

[0066] The difference between this embodiment and the above-mentioned embodiment lies in the different type of the sensor 501. The sensor 501 is a light intensity attenuation sensor, that is, the wear degree of the finger 31 is detected by the optoelectronic method. By measuring the characteristics of the optical signal (such as light intensity, spot size, beam offset, etc.), the distance between the light intensity attenuation sensor and the target object (such as the top disc 201 of the piston 21) is calculated. Using this principle, the wear amount of the finger 31 can be indirectly judged by monitoring the change in the distance between the light intensity attenuation sensor and the top of the piston 21. It should be noted that the working principle of the light intensity attenuation sensor belongs to the prior art and will not be described here.

[0067] Embodiment Four

[0068] The difference between this embodiment and the above-mentioned embodiment lies in the different type of the sensor 501. The sensor 501 is a pressure sensor, that is, the pressure method is adopted to convert the wear degree of the finger 31 into a pressure value through force conduction, and the wear degree of the finger 31 is determined by sampling the pressure value converted into an electrical signal. Specifically, the wear amount of the finger 31 is indirectly judged by monitoring the pressure change between the pressure sensor and the top disc 201 of the piston 21. The core principle is that when the clamping surface of the finger 31 wears and the gap between the finger 31 and the product increases, the contact pressure between the pressure sensor and the top of the piston 21 will change, and the wear amount of the finger 31 can be deduced by measuring this pressure change. It should be noted that the working principle of the pressure sensor belongs to the prior art and will not be described here.

[0069] Embodiment Five

[0070] The difference between this embodiment and the above-mentioned embodiment lies in the different type of the sensor 501. The sensor 501 is an inductive proximity switch, and the inductive proximity switch is a type of position sensor. In this embodiment, the change in the inductive distance between the inductive proximity switch and the top disc 201 of the piston 21 is monitored by the inductive proximity switch method, and the wear amount of the finger 31 is indirectly judged. The core principle is that when the finger 31 wears and the gap between the finger 31 and the product increases, the inductive distance of the inductive proximity switch will change accordingly, and the wear amount of the finger 31 can be deduced by measuring this distance change. It should be noted that the working principle of the inductive proximity switch belongs to the prior art and will not be described here.

[0071] Embodiment Six

[0072] The difference between this embodiment and the above - mentioned embodiment lies in the different type of the sensor 501. The sensor 501 is an ultrasonic sensor. According to the principle of ultrasonic ranging, when ultrasonic waves propagate in a material and encounter different medium interfaces (for example, the wear of the finger 31 will cause a change in the gap between the top of the piston rod 20 and the ultrasonic sensor), reflections will occur. By analyzing the time difference or amplitude change of the reflected wave, the distance can be calculated, and then the wear amount of the finger 31 can be deduced. It should be noted that the working principle of the ultrasonic sensor 501 belongs to the prior art and will not be described here.

[0073] The above - mentioned are only the preferred embodiments of the present invention. It does not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A pneumatic gripper, comprising a cylinder block, a piston rod, a piston and two fingers. A piston chamber is arranged axially in the cylinder block, and a partition seat is hermetically arranged circumferentially in the piston chamber. The first end of the piston rod slidably penetrates through the partition seat axially of the cylinder block in a sealed manner, and the second end of the piston rod slidably penetrates out of the piston chamber axially of the cylinder block in a sealed manner. The piston is fixed on the piston rod, and the piston is slidably arranged in the piston chamber in a sealed manner, and the piston is located between the partition seat and the bottom of the piston chamber. An intake chamber is formed between the piston and the partition seat, and an exhaust chamber is formed between the piston and the bottom of the piston chamber. An intake port communicating with the intake chamber and an exhaust port communicating with the exhaust chamber are arranged on the cylinder block. The second end of the piston rod is drivingly connected to the two fingers slidably arranged on the cylinder block for driving the opening and closing of the two fingers; characterized in that, A sealing cavity that is hermetically communicated with the piston cavity is provided at the top of the piston cavity. A sensor is installed in the sealing cavity. The sensor is electrically connected to a control platform disposed outside the pneumatic gripper. The sensor determines the wear degree of the finger by detecting the distance between the piston rod and the sensor.

2. The pneumatic gripper according to claim 1, characterized in that, It further includes a connecting rod mechanism and two finger mounting seats. A slide rail is fixed to the bottom of the cylinder block. The slide rail extends along a direction perpendicular to the axial direction of the cylinder block. The finger mounting seats are slidably arranged on the slide rail along the extending direction of the slide rail. The piston rod is drivingly connected to the two finger mounting seats through the connecting rod mechanism. The piston rod drives the connecting rod mechanism to drive the two finger mounting seats to slide towards or away from each other along the extending direction of the slide rail. The two fingers are respectively arranged on the two finger mounting seats.

3. The pneumatic gripper according to claim 1, characterized in that, A buffer pad is provided at the bottom of the air outlet cavity to prevent the piston from making hard contact with the bottom wall of the air outlet cavity.

4. The pneumatic gripper according to claim 2, characterized in that, The connecting rod mechanism includes a first rotating shaft, a second rotating shaft, a first connecting rod and a second connecting rod. A groove communicated with the piston cavity is formed in the bottom of the cylinder block along the extending direction of the slide rail. The first rotating shaft and the second rotating shaft are respectively horizontally rotatably arranged at two ends in the groove. The extending directions of the first rotating shaft and the second rotating shaft are perpendicular to the extending direction of the slide rail. The first connecting rod and the second connecting rod are respectively sleeved on the first rotating shaft and the second rotating shaft. And two ends of the first connecting rod are respectively connected to one finger mounting seat and the second end of the piston rod. Two ends of the second connecting rod are respectively connected to the other finger mounting seat and the second end of the piston rod.

5. The pneumatic gripper according to claim 4, characterized in that, A chute is formed in the bottom of the slide rail along the extending direction of the slide rail. The two finger mounting seats are slidably connected to the chute. Two kidney-shaped grooves are formed in the top surface of the slide rail. The kidney-shaped grooves extend along the extending direction of the slide rail. The two kidney-shaped grooves are respectively used to avoid the first connecting rod and the second connecting rod.

6. The pneumatic gripper according to claim 5, characterized in that, A rolling connection is provided between the chute and the finger mounting seat.

7. The pneumatic gripper according to claim 6, characterized in that, First arc-shaped guiding grooves are formed in opposite side walls of the chute along the extending direction of the chute. Second arc-shaped guiding grooves are formed in opposite side walls of the finger mounting seat along the extending direction of the chute. Each first arc-shaped guiding groove corresponds to each second arc-shaped guiding groove. A ball is connected between the first arc-shaped guiding groove and the second arc-shaped guiding groove. The ball is in spherical contact with the first arc-shaped guiding groove and the second arc-shaped guiding groove.

8. The pneumatic gripper according to claim 7, characterized in that, Blocking plates are provided at opposite ends of the finger mounting seat. The blocking plates are used to prevent the balls between the first arc-shaped guiding groove and the second arc-shaped guiding groove from falling off.

9. The pneumatic gripper according to claim 4, wherein Connection holes are formed in the upper surface of the finger mounting seat. The first connecting rod is connected to the connection hole on one finger mounting seat by a ball head. The second connecting rod is connected to the connection hole on the other finger mounting seat by a ball head.

10. A pneumatic gripper according to claim 1, characterized in that, A disc is provided at the top end of the piston rod. The outer diameter of the disc is larger than the outer diameter of the top end of the piston rod. A cylindrical groove is formed in the upper surface of the isolation seat. The cylindrical groove is coaxial with the disc. The inner diameter of the cylindrical groove is larger than the outer diameter of the disc.

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