Force control clamping device

Abstract

The invention discloses a force control clamping device which comprises a mounting plate, a control valve bank, a three-position air cylinder, a connecting mechanism, a clamp assembly and a material tray, the connecting mechanism penetrates through and fixes the mounting plate, the top end of the connecting mechanism is connected with the three-position air cylinder, the bottom end of the connecting mechanism is connected with the clamp assembly, and the control valve bank is fixed to the mounting plate. The output end of the clamping assembly is connected with the three-position air cylinder so as to control the three-position air cylinder to reach a contraction position, a force control start position and a force control end position respectively, the clamping assembly is used for clamping the material disc, and the material disc is used for fixing a sample. The device has the advantages that accurate lifting control over the material disc is achieved, accurate rotation control over the material disc is also achieved, it is possible to adjust the pressing degree of samples according to different sample specifications, and the automation degree of metallographic corrosion is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation, and particularly relates to a force-controlled clamping device, which is applicable to the automatic corrosion link of metallographic tests. Background Art

[0002] The invention patent of CN202211656259.2 discloses an automatic metallographic inspection system based on a double-positioning tray. Its positive positioning structure controls the clamping of the tray through the contraction of a cylinder, where the neck ring groove of the central column of the tray cooperates with the inner cylinder and steel balls of the clamping jaw. The advantage of this patent is its strong applicability, which can take into account the automatic transfer of the tray between multiple devices. However, during the processes of sample corrosion and grinding / polishing, it is necessary to adjust the pressing degree of the sample according to different sample specifications to complete the grinding / polishing processes of different types of samples. This structure cannot achieve precise control of the grinding / polishing force, which affects the automatic process of metallographic corrosion. Summary of the Invention

[0003] Object of the Invention: Aiming at the deficiencies of the prior art, the present invention proposes a force-controlled clamping device, aiming to precisely control the pressing degree during the grinding / polishing process of the sample and improve the degree of automation of metallographic corrosion.

[0004] Technical Solution: A force-controlled clamping device includes a mounting plate, a control valve group, a three-position cylinder, a connecting mechanism, a fixture assembly, and a tray. The connecting mechanism passes through and is fixed to the mounting plate, with its top connected to the three-position cylinder and its bottom connected to the fixture assembly. The control valve group is fixed on the mounting plate, and its output end is connected to the three-position cylinder to control the three-position cylinder to reach the contraction position, the force control starting position, and the force control ending position respectively. The fixture assembly is used to clamp the tray, and the tray is used to fix the sample.

[0005] The principle of the present invention is: The control valve group is used to drive the three-position cylinder for force-position control. The contraction position is the control original position, the force control starting position is the control middle position, and the force control ending position is the farthest output position. Among them, the contraction position and the force control starting position adopt conventional control, which can quickly return to the original position and pre-position. Dynamic force control is adopted between the force control starting position and the force control ending position, which can precisely control the pressing degree, so as to meet the grinding / polishing requirements of different sample specifications.

[0006] Further, the fixture assembly includes a transmission sleeve, an outer sleeve, an inner sleeve, a piston, a connection seat, and steel balls. The upper and lower ends of the transmission sleeve are hermetically connected to the connection mechanism and the outer sleeve respectively. The inner sleeve is hermetically nested inside the outer sleeve. After the transmission sleeve, the outer sleeve, and the inner sleeve are assembled, a hollow sealed cavity is formed. The piston and the connection seat are installed in the hollow sealed cavity. The top of the connection seat is connected to the piston, and the bottom is connected to the inner sleeve. The connection mechanism is inserted into the hollow sealed cavity and sequentially outputs the force of the three-position cylinder to the piston, the connection seat, and the inner sleeve, driving the inner sleeve to slide along the inner wall of the outer sleeve. A steel ball chute is provided on the inner wall of the outer sleeve, a tapered hole is provided on the side wall of the inner sleeve, the steel balls are stuck into the tapered hole, and both sides of the steel balls respectively protrude out of the tapered hole. The material tray is provided with a central column, and a neck ring groove is provided on the central column. The steel balls contract inward along the tapered hole under the extrusion of the steel ball chute to be stuck into the neck ring groove and retract into the steel ball chute to release the central column. This structure is applicable to the clamping of a material tray with a neck ring groove. Using the same set of cylinders as the power output, it not only realizes force control but also realizes the clamping of the material tray, with strong versatility and a compact structure.

[0007] Further, the fixture assembly further includes a compression spring. A first retaining ring is provided on the connection seat, and a second retaining ring is provided inside the outer sleeve. The compression spring is sleeved on the connection seat, and the upper and lower ends are respectively limited by the first retaining ring and the second retaining ring to assist the piston to return to its original position after the three-position cylinder has no power output in the hollow sealed cavity.

[0008] Further, a rotation assembly is further included. The connection mechanism includes a support sleeve, a ball spline, a rotary joint, and a vent screw. The ball spline includes a spline shaft and a spline nut connected to each other. The fixed ends of the support sleeve and the spline nut are installed on the mounting plate. The top of the support sleeve is fixedly connected to the three-position cylinder, and the ball spline is clamped inside. The movable ends of the spline shaft and the spline nut penetrate through the mounting plate. The top end of the spline shaft is connected to the three-position cylinder through the rotary joint, and the bottom end is hermetically fixedly connected to the vent screw. The vent screw is inserted into the hollow sealed cavity. The spline shaft and the transmission sleeve are connected by a key. The rotation assembly includes a rotation drive, a driving pulley, a synchronous belt, a driven pulley, and a shrink disc. The rotation drive is fixed on the mounting plate, and the driving pulley is fixedly provided at the output end. The driven pulley is installed on the movable end of the spline nut through the shrink disc. The synchronous belt is wound around the driving pulley and the driven pulley to form a transmission. In this structure, the rotation of the material tray can be realized through the cooperation of the rotation assembly and the spline nut, and it does not affect the lifting control of the material tray.

[0009] Furthermore, the connection mechanism also includes a transition sleeve and a bearing. The output end of the three-position cylinder is sleeved on the upper part of the transition sleeve, and the spline shaft is sleeved on the lower part through the bearing to maintain the stability of the connection structure.

[0010] Furthermore, the clamp assembly also includes a floating pin and a pin hole spring. A pin hole is provided at the bottom of the outer sleeve. The pin hole spring and the floating pin are connected and installed in the pin hole, and the outer protrusion of the floating pin is exposed outside the outer sleeve. A circumferential positioning hole is provided on the material tray, and the outer protrusion of the floating pin is aligned with the circumferential positioning hole to achieve precise transmission of the material tray during rotation.

[0011] Furthermore, the connection mechanism also includes an origin screw and a sensor. The origin screw is fixed on the side wall of the spline shaft. The sensor passes through the support sleeve and faces the origin screw to accurately locate the rotation origin.

[0012] Furthermore, it also includes a protective cover, which is circumferentially arranged on the clamp assembly and covers the material tray to protect the material tray and the sample installed on the material tray.

[0013] Beneficial effects: Compared with the prior art, the advantages of the present invention are: it not only realizes the precise lifting and lowering control of the material tray, but also realizes the precise rotation control of the material tray, making it possible to adjust the degree of sample depression according to different sample specifications, thereby improving the degree of automation of metallographic corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 This is the pneumatic principle diagram of the control valve group; Figure 3 It is a schematic diagram of three-position cylinder control; Figure 4 It is a cross-sectional view of the connection structure of the clamp assembly; Figure 5 for Figure 4 A magnified schematic diagram of the D position in the middle; Figure 6 It is a cross-sectional view of the inner sleeve connection structure; Figure 7 for Figure 6 A magnified schematic diagram of the E position in the middle; Figure 8 is a cross-sectional view of the connecting mechanism; Figure 9 It is a cross-sectional view of the ball spline connection structure; Figure 10 It is a three-dimensional diagram of the rotating component connection structure. DETAILED DESCRIPTION

[0015] The present invention will be further clarified below in conjunction with the accompanying drawings and specific embodiments. These embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0016] A force control clamping device is applicable to scenarios where precise control of the lifting position is required, such as metallographic corrosion, automated grinding and polishing scenarios, etc. As shown in the attached Figure 1 figures, it includes a mounting plate 1, a control valve group 2, a three-position cylinder 3, a connecting mechanism 4, a fixture assembly 5, a tray 6, a rotating assembly 7, and a protective cover 8.

[0017] The connecting mechanism 4 passes through and is fixedly installed on the mounting plate 1, with its top connected to the three-position cylinder 3 and its bottom connected to the fixture assembly 5. The control valve group 2 is fixed on the mounting plate 1, and its output end is connected to the three-position cylinder 3 to control the three-position cylinder 3 to reach the retracted position, the force control starting position, and the force control ending position respectively. The fixture assembly 5 is used to clamp the tray 6, and the tray 6 is used to fix the specimen. The protective cover 8 is circumferentially arranged on the fixture assembly 5 and covers the tray 6.

[0018] In this embodiment, the control logic of the control valve group and the three-position cylinder is briefly described: As shown in the attached Figure 2 、 3 figures: When the third solenoid valve operates, air enters through the air vent A, and the cylinder retracts to the retracted position; when the third solenoid valve and the first solenoid valve operate, air enters through the air vents A and C, and the cylinder extends to the force control starting position; when the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve operate simultaneously, air enters through the air vents A, B, and C at the same time, and the cylinder gradually extends to the force control ending position.

[0019] During the gradual movement from the force control starting position to the force control ending position, the output force F is: F = P B * S B2 +(S A2 - S B1 ) * P C - P A * S A1 Wherein, P A , P B , P C are the air pressures of the three air vents A, B, and C of the three-position cylinder respectively; S A1 and S A2 are the effective acting areas on the left and right sides of the first piston in the three-position cylinder respectively; S B1 and S B2 are the effective acting areas on the left and right sides of the second piston in the three-position cylinder respectively; By controlling the pressures of the air inlets B and C respectively through the control valve group, different cylinder output forces can be obtained, so as to precisely control the pressing degree of the three-position cylinder from the force control starting position to the force control ending position.

[0020] Meanwhile, in this embodiment, a single cylinder is used to drive both the lifting of the device and the clamping of the tray. The specific structure is as follows: As shown in the appended Figures 4 - 7 figure, the fixture assembly 5 includes a transmission sleeve 5a, an outer sleeve 5b, an inner sleeve 5c, a piston 5d, a connecting seat 5e, steel balls 5f, and a compression spring 5g.

[0021] As shown in the appended Figure 4 , 6 figure, the upper and lower ends of the transmission sleeve 5a are hermetically connected to the connecting mechanism 4 and the outer sleeve 5b respectively. The inner sleeve 5c is hermetically nested inside the outer sleeve 5b. After the transmission sleeve 5a, the outer sleeve 5b, and the inner sleeve 5c are assembled, a hollow sealed cavity is formed. The piston 5d and the connecting seat 5e are installed in the hollow sealed cavity. The top of the connecting seat 5e is connected to the piston 5d, and the bottom is connected to the inner sleeve 5c. The connecting mechanism 4 is inserted into the hollow sealed cavity and sequentially outputs the force of the three-position cylinder 3 to the piston 5d, the connecting seat 5e, and the inner sleeve 5c, driving the inner sleeve 5c to slide along the inner wall of the outer sleeve 5b. As shown in the appended Figure 7 figure, a steel ball chute 5b-1 is provided on the inner wall of the outer sleeve 5b, and a tapered hole 5c-1 is opened on the side wall of the inner sleeve 5c. The steel balls 5f are stuck into the tapered hole 5c-1, and both sides of them are respectively exposed outside the tapered hole 5c-1. The tray 6 is provided with a central column 61, and a neck ring groove 61a is opened on the central column 61. The steel balls 5f contract inward along the tapered hole 5c-1 under the extrusion of the steel ball chute 5b-1 to be stuck into the neck ring groove 61a, and retreat into the steel ball chute 5b-1 to release the central column 61. As shown in the appended Figure 5 figure, a first retaining ring 5e-1 is provided on the connecting seat 5e, and a second retaining ring 5b-2 is provided inside the outer sleeve 5b. The compression spring 5g is sleeved on the connecting seat 5e, and the upper and lower ends are respectively limited by the first retaining ring 5e-1 and the second retaining ring 5b-2.

[0022] In this structure, when it is necessary to clamp the tray, the three-position cylinder 3 outputs compressed air into the hollow sealed cavity, sequentially pushing the piston 5d, the connecting seat 5e, and the inner sleeve 5c to move downward. The steel balls 5f retreat outward into the steel ball chute 5b-1. Then, the central column 61 of the tray is inserted into the inner sleeve 5c. After that, the three-position cylinder 3 sucks air, and the compression spring 5g rebounds, driving the connecting seat 5e, the inner sleeve 5c, and the piston 5d back to their original positions. The steel balls 5f are gradually stuck into the neck ring groove 61a through the tapered hole 5c-1 under the extrusion of the steel ball chute 5b-1, thus clamping the central column 61 of the tray to form a clamp. The process of unloading the tray is the opposite and will not be elaborated here. Multiple such structures can be circumferentially and uniformly arranged along the inner sleeve and the outer sleeve to improve stability.

[0023] In addition, this embodiment also realizes the rotation control of the tray, enabling the automatic rotation of the tray from the clamping device, which is more convenient for corrosion and grinding operations. The specific structure is as follows: As shown in the appended Figure 4 ,6 As shown in Figures 8, 9 and 10, the connecting mechanism 4 includes a support sleeve 41, a ball spline 42, a rotary joint 43, a vent screw 44, a transition sleeve 45, a bearing 46, an origin screw 47 and a sensor 48.

[0024] As attached Figure 8 As shown, the ball spline 42 includes a spline shaft 42a and a spline nut 42b connected to each other. The fixed ends of the support sleeve 41 and the spline nut 42b are installed on the mounting plate. The top of the support sleeve 41 is fixedly connected to the three-position cylinder 3, and the ball spline 42 is clamped inside. The movable ends of the spline shaft 42a and the spline nut 42b are penetrated through the mounting plate 1. Figure 4 , 8 As shown, the top of the spline shaft 42a is connected to the three-position cylinder 3 through a rotary joint 43, and the bottom end is sealed and fixed with a vent screw 44, which is inserted into the hollow sealing cavity. The spline shaft 42a and the transmission sleeve 5a are connected by a key. Figure 8 , 9 As shown, the output end of the three-position cylinder 3 is sleeved on the upper part of the transition sleeve 45, and the spline shaft 42a is sleeved on the lower part through the bearing 46. The origin screw 47 is fixed on the side wall of the spline shaft 42a, and the sensor 48 passes through the support sleeve 41 and faces the origin screw 47.

[0025] like Figure 6 As shown, the clamp assembly 5 also includes a floating pin 5h and a pin hole spring 5i. A pin hole 5b-3 is provided at the bottom of the outer sleeve 5b. The pin hole spring 5i and the floating pin 5h are connected and installed in the pin hole 5b-3, and the outer protrusion of the floating pin 5h is exposed outside the outer sleeve 5b. A circumferential positioning hole 62 is provided on the material tray 6, and the outer protrusion of the floating pin 5h is aligned with the circumferential positioning hole 62.

[0026] like Figure 10 As shown, the rotating assembly 7 includes a rotating drive 71, a driving pulley 72, a synchronous belt 73, a driven pulley 74, and an expansion sleeve 75. The rotating drive 71 is fixed on the mounting plate 1, the driving pulley 72 is fixed at the output end, the driven pulley 74 is installed on the movable end of the spline nut 42b through the expansion sleeve 75, and the synchronous belt 73 is wrapped around the driving pulley 72 and the driven pulley 74 to form a transmission.

[0027] In this structure, the top of the spline shaft 42a is connected to the three-position cylinder 3 through a rotary joint 43, and the bottom realizes air pressure transmission through a vent screw 44. It is fixed by a key connection and an over sleeve 45 to achieve rotary transmission. At the same time, a spline nut 42b is used to connect to the rotary drive 71. The movable end of the spline nut 42b can transmit the rotary force to the spline shaft 42a without affecting the lifting of the spline shaft 42a. This structure not only ensures the stability of the lifting structure but also avoids the influence of the rotary structure on the lifting structure. At the same time, in this structure, precise rotary control is achieved by inserting a floating pin into the circumferential positioning hole to avoid rotary slip, and then the positioning detection of the rotary origin is realized through the alignment detection of the origin screw and the sensor, realizing the stability and controllability of the rotary motion.

[0028] When the clamping device of this embodiment is in use, first, the pressure output of the three-position cylinder drives the up and down sliding of the inner sleeve, squeezing the steel balls to complete the clamping of the tray. Then, through the precise control of the retraction position, force control start position, and force control end position of the three-position cylinder, the tray is driven to reach the specified working position. After that, the rotary drive outputs power. Driven by the synchronous belt, the driving pulley drives the driven pulley to rotate, and then drives the spline shaft, fixture assembly, and tray to rotate in sequence, thus completing subsequent automated corrosion and grinding operations.

[0029] The clamping device of this embodiment not only realizes the precise lifting control of the tray but also realizes the precise rotary control of the tray, making it possible to adjust the pressing degree of the specimen according to different specimen specifications and improving the automation degree of metallographic corrosion.

Claims

1. A force-controlled clamping device, characterized in that: It includes a mounting plate (1), a control valve group (2), a three-position cylinder (3), a connecting mechanism (4), a fixture assembly (5), and a tray (6). The connecting mechanism (4) passes through and is fixed to the mounting plate (1), with its top connected to the three-position cylinder (3) and its bottom connected to the fixture assembly (5). The control valve group (2) is fixed on the mounting plate (1), and its output end is connected to the three-position cylinder (3) to control the three-position cylinder (3) to reach the retracted position, the force control starting position, and the force control ending position respectively. The fixture assembly (5) is used to clamp the tray (6), and the tray (6) is used to fix the specimen.

2. The force control clamping device according to claim 1, wherein: The fixture assembly (5) includes a transmission sleeve (5a), an outer sleeve (5b), an inner sleeve (5c), a piston (5d), a connecting seat (5e), and steel balls (5f). The upper and lower ends of the transmission sleeve (5a) are hermetically connected to the connecting mechanism (4) and the outer sleeve (5b) respectively. The inner sleeve (5c) is hermetically nested inside the outer sleeve (5b). After the transmission sleeve (5a), the outer sleeve (5b), and the inner sleeve (5c) are assembled, a hollow sealed cavity is formed. The piston (5d) and the connecting seat (5e) are installed in the hollow sealed cavity. The top of the connecting seat (5e) is connected to the piston (5d), and the bottom is connected to the inner sleeve (5c). The connecting mechanism (4) is inserted into the hollow sealed cavity and sequentially outputs the acting force of the three-position cylinder (3) to the piston (5d), the connecting seat (5e), and the inner sleeve (5c), driving the inner sleeve (5c) to slide along the inner wall of the outer sleeve (5b). A steel ball chute (5b-1) is provided on the inner wall of the outer sleeve (5b), and a tapered hole (5c-1) is opened on the side wall of the inner sleeve (5c). The steel balls (5f) are snapped into the tapered hole (5c-1), and both sides of the steel balls (5f) are exposed outside the tapered hole (5c-1). The tray (6) is provided with a central column (61), and a neck ring groove (61a) is opened on the central column (61). The steel balls (5f) are squeezed in the steel ball chute (5b-1) and contract inward along the tapered hole (5c-1) to snap into the neck ring groove (61a), or retract into the steel ball chute (5b-1) to release the central column (61).

3. The force control clamping device according to claim 2, characterized in that: The fixture assembly (5) further includes a compression spring (5g). A first retaining ring (5e-1) is provided on the connecting seat (5e), and a second retaining ring (5b-2) is provided inside the outer sleeve (5b). The compression spring (5g) is sleeved on the connecting seat (5e), and its upper and lower ends are limited by the first retaining ring (5e-1) and the second retaining ring (5b-2) respectively.

4. A force-controlled clamping device according to claim 2, characterized in that: It also includes a rotating assembly (7), wherein the connecting mechanism (4) includes a support sleeve (41), a ball spline (42), a rotating joint (43), and a vent screw (44), wherein the ball spline (42) includes a spline shaft (42a) and a spline nut (42b) connected to each other, wherein the fixed ends of the support sleeve (41) and the spline nut (42b) are mounted on the mounting plate, the top of the support sleeve (41) is fixedly connected to the three-position cylinder (3), and the ball spline (42) is clamped inside, the movable ends of the spline shaft (42a) and the spline nut (42b) pass through the mounting plate (1), and the top end of the spline shaft (42a) is connected to the three-position cylinder (3) through the rotating joint (43). The cylinder (3) and the bottom end seal are fixedly connected to the vent screw (44), the vent screw (44) is inserted into the hollow sealing cavity, and the spline shaft (42a) and the transmission sleeve (5a) are connected by a key; the rotating assembly (7) comprises a rotating drive (71), a driving pulley (72), a synchronous belt (73), a driven pulley (74), and an expansion sleeve (75); the rotating drive (71) is fixed on the mounting plate (1), the driving pulley (72) is fixed on the output end, the driven pulley (74) is installed on the movable end of the spline nut (42b) through the expansion sleeve (75), and the synchronous belt (73) is wound around the driving pulley (72) and the driven pulley (74) to form a transmission.

5. The force control clamping device according to claim 4, wherein: The connection mechanism (4) further comprises a transition sleeve (45) and a bearing (46); the transition sleeve (45) is sleeved on the output end of the three-position cylinder (3) at its upper portion, and is sleeved on the spline shaft (42a) at its lower portion via the bearing (46).

6. The force control clamping device according to claim 4, wherein: The clamp assembly (5) also includes a floating pin (5h) and a pin hole spring (5i). A pin hole (5b-3) is provided at the bottom of the outer sleeve (5b). The pin hole spring (5i) and the floating pin (5h) are connected and installed in the pin hole (5b-3). The outer protrusion of the floating pin (5h) is exposed outside the outer sleeve (5b). A circumferential positioning hole (62) is provided on the material tray (6), and the outer protrusion of the floating pin (5h) is aligned with the circumferential positioning hole (62).

7. The force control clamping device according to claim 6, wherein: The connecting mechanism (4) further comprises an origin screw (47) and a sensor (48), wherein the origin screw (47) is fixed on the side wall of the spline shaft (42a), and the sensor (48) passes through the support sleeve (41) and faces the origin screw (47).

8. The force control clamping device according to claim 1, wherein: It also comprises a protective cover (8), which is arranged on the clamp assembly (5) along the circumferential direction and covers the material tray (6).

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