Wellhead falling object prevention device for petroleum drilling

Abstract

The utility model relates to the technical field of oil drilling mouth falling prevention, in particular to an oil drilling mouth falling prevention device which comprises a drilling pipeline, the drilling pipeline is arranged in soil, a cover plate is installed over the drilling pipeline, a round hole is formed in the middle of the cover plate, and a round groove is formed in the middle of the inner wall of the round hole in a circle. Two groups of long arc-shaped grooves are formed in the edge, close to the circular hole, of the cover plate, and two groups of short arc-shaped grooves are formed between the outer edge and the long arc-shaped grooves in the cover plate; the fixing assembly is arranged below the cover plate, and the fixing assembly is used for fixing the cover plate on the inner wall of the drilling pipeline; the opening and closing assembly is arranged in a circular groove formed in the middle of the inner wall of the circular hole, and the opening and closing assembly is used for conveniently placing a drill bit. The problems that a traditional petroleum drilling well mouth falling object preventing device is tedious in operation and difficult to observe, and a movable fence is poor in stability are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of preventing objects from falling from a petroleum drilling wellhead, in particular to a device for preventing objects from falling from a petroleum drilling wellhead. Background Art

[0002] Traditional oil drilling wellheads are prone to falling debris during operations due to their openness and height differences. These foreign objects, including tools, parts, and rock fragments, can damage critical equipment like the drill pipe and drill bit, disrupt drilling operations, and even lead to safety accidents. Currently, most existing oil drilling wellhead fall-object prevention devices on the market utilize simple covering or enclosure structures, such as fixed covers and movable fences. However, these devices present several practical challenges.

[0003] In the prior art, fixed covers are cumbersome to operate when the wellhead needs to be frequently opened and closed, and it is not easy to observe the conditions inside the well; although movable fences are easy to operate, they have poor stability and are easily displaced or collapsed due to wind, collision, etc., and have poor practicality. Therefore, the present application discloses an oil drilling wellhead falling object prevention device to solve the problems of traditional oil drilling wellhead falling object prevention devices being cumbersome to operate, difficult to observe, and poor stability of movable fences. Utility Model Content

[0004] In view of this, the purpose of the present invention is to provide an oil drilling wellhead anti-falling object device to solve the problems of traditional oil drilling wellhead anti-falling object devices such as cumbersome operation, difficult observation and poor stability of movable fences.

[0005] Based on the above objectives, the present invention provides a device for preventing falling objects at a wellhead of a petroleum drilling well, comprising: a drilling pipe, the drilling pipe being disposed in the soil, a cover plate being installed directly above the drilling pipe, the cover plate having a circular hole in the middle, a circular groove being formed around the middle of the inner wall of the circular hole, two groups of long arc-shaped grooves being formed on the cover plate near the edge of the circular hole, and two groups of short arc-shaped grooves being formed between the outer edge of the cover plate and the long arc-shaped grooves;

[0006] A fixing assembly, the fixing assembly being arranged below the cover plate and being used for fixing the cover plate on the inner wall of the drilling pipe;

[0007] An opening and closing component is arranged in the circular groove opened in the middle of the inner wall of the circular hole, and the opening and closing component is used to facilitate the insertion of the drill bit.

[0008] The top end of the first concave mounting block is fixedly mounted on the bottom surface of the cover plate, and the top end of the first concave mounting block is fixedly mounted on the bottom surface of the cover plate, and the top end of the first concave mounting block is fixedly mounted on the bottom surface of the cover plate, and the top end of the first concave mounting block is fixedly mounted on the bottom surface of the cover plate, and the first rotating rod is installed on the inner wall of the groove of the first concave mounting block, and a mounting ring is rotatably installed on the first rotating rod, and an L-shaped clamp arm is installed on one side wall of the mounting ring.

[0009] Preferably, the L-shaped clamp arm is installed inverted, and a second concave mounting block is installed on the outer side of the top surface of the short side of the L-shaped clamp arm, a second rotating rod is installed on the inner wall of the groove of the second concave mounting block, and one end of a vertical guide rod is installed on the second rotating rod. The end of the vertical guide rod is located at the position of the second rotating rod and is provided with a circular hole with the same diameter as the second rotating rod, and a vertical spring is sleeved on the vertical guide rod.

[0010] Preferably, the top end of the vertical guide rod is slidably inserted into the bottom of the cover plate, and the bottom of the cover plate is located at the position of the vertical guide rod and is provided with a circular groove with the same diameter as the vertical guide rod. One end of the vertical spring abuts against the side wall of the second rotating rod, and the other end of the vertical spring abuts against the bottom surface of the cover plate.

[0011] Preferably, a through hole is opened in the middle of the long side of the L-shaped clamp arm, a horizontal guide rod is slidably inserted into the hole, an arc-shaped support plate is installed at the end of the horizontal guide rod close to the inner wall of the drilling pipe, and a limiting ring is installed at the end of the horizontal guide rod away from the inner wall of the drilling pipe. A horizontal spring is sleeved on the horizontal guide rod, one end of the horizontal spring abuts against the side wall of the arc-shaped support plate, and the other end of the horizontal spring abuts against the inner wall of the L-shaped clamp arm.

[0012] Preferably, the opening and closing assembly includes an operating circular plate, and the top of the operating circular plate is provided with connecting columns at the positions of the two groups of the long arc grooves, and the top of the two groups of connecting columns is provided with a second circular armrest, and the bottom surface of the operating circular plate is evenly arranged with multiple groups of oblique straight line grooves, and the operating circular plate is evenly spaced and provided with multiple groups of oblique triangular plates on one side of the oblique straight line grooves, and the number of the oblique triangular plates is the same as the number of the oblique straight line grooves, and each group of the oblique triangular plates on one side of the operating circular plate is provided with a limiting strip, and the limiting strip is slidably installed in the oblique straight line groove, and the width of the limiting strip is the same as the width of the oblique straight line groove, and the oblique triangular plate slides in the oblique straight line groove through the limiting strip.

[0013] Preferably, a mounting post is installed on the side wall of each group of the oblique triangular plates away from the operating circular plate, and the mounting post is cylindrical. A fixed base plate is installed on the side of the oblique triangular plates where the mounting post is installed, and a plurality of groups of oblique arc grooves are evenly arranged on the fixed base plate. The number of the oblique arc grooves is the same as the number of the mounting posts, and the outer ends of each group of the mounting posts are slidably inserted into the oblique arc grooves at the corresponding positions, and the other side of the fixed base plate is fixedly installed on the bottom surface of the circular groove.

[0014] Beneficial effects of the utility model:

[0015] Through the design of the opening and closing components, the placement of the drill bit can be easily controlled, while ensuring that the wellhead remains closed during the drilling process, effectively preventing falling objects from entering the drilling pipe, and avoiding equipment damage and safety accidents caused by falling objects. The ingenious design of the fixing component enables the cover plate to be firmly fixed to the inner wall of the drilling pipe. At the same time, by adjusting the support column and L-shaped clamp arm and other components, the cover plate can be easily installed and removed, greatly improving the operating efficiency. Through the coordinated use of vertical springs and horizontal springs, the L-shaped clamp arm can fit tightly to the inner wall of the drilling pipe, and maintain a stable fixing effect even in vibration or impact environments. In addition, the overall device has a compact structure and a reasonable design. The connection between the components is firm and reliable, which is convenient for daily maintenance and inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the three-dimensional structure of the utility model;

[0018] Figure 2 This is a schematic diagram of a partial structural cross-section of the present invention;

[0019] Figure 3 For this utility model Figure 2 A in the middle is an enlarged structural diagram;

[0020] Figure 4 This is a schematic diagram of the three-dimensional structure of the fixing component of the utility model;

[0021] Figure 5 This is a schematic diagram of the internal structure of the utility model.

[0022] The following are marked in the figure:

[0023] 1. Drilling pipe; 2. Cover plate; 3. Circular hole; 4. Circular groove; 5. Long arc groove; 6. Short arc groove; 7. Connecting column; 8. Support column; 9. Arc groove; 10. Operating circular plate; 11. First circular handrail; 12. Second circular handrail; 13. First concave mounting block; 14. Mounting ring; 15. L-shaped clamping arm; 16. Retaining spring; 17. Limiting circular block; 18. Vertical guide rod; 19. Vertical spring; 20. Second concave mounting block; 21. Arc retaining plate; 22. Directional pulley; 23. Horizontal guide rod; 24. Horizontal spring; 25. Oblique linear groove; 26. Mounting column; 27. Oblique triangle plate; 28. Fixed base plate; 29. Oblique arc groove. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0025] It should be noted that, unless otherwise defined, the technical or scientific terms used in this utility model should have the usual meanings understood by people with ordinary skills in the field to which this utility model belongs. The "first", "second" and similar words used in this utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0026] The utility model provides Figures 1 to 5The device for preventing falling objects from a wellhead of an oil drilling well is shown, comprising: a drilling pipe 1, the drilling pipe 1 being set in the soil, a cover plate 2 being installed directly above the drilling pipe 1, a circular hole 3 being opened in the middle of the cover plate 2, a circular groove 4 being opened in the middle of the inner wall of the circular hole 3, two groups of long arc grooves 5 being opened on the edge of the cover plate 2 near the circular hole 3, and two groups of short arc grooves 6 being opened on the cover plate 2 between the outer edge and the long arc groove 5; a fixing assembly being set below the cover plate 2, and being used to fix the cover plate 2 on the inner wall of the drilling pipe 1; an opening and closing assembly being set in the circular groove 4 opened in the middle of the inner wall of the circular hole 3, and being used to facilitate the insertion of the drill bit. The design of the opening and closing assembly can conveniently control the The drill bit is placed, and at the same time, it is ensured that the wellhead remains closed during the drilling process, which effectively prevents falling objects from entering the drilling pipe 1 and avoids equipment damage and safety accidents caused by falling objects. The ingenious design of the fixing assembly enables the cover plate 2 to be firmly fixed to the inner wall of the drilling pipe 1. At the same time, by adjusting the support column 8 and the L-shaped clamp arm 15 and other components, the cover plate 2 can be easily installed and removed, which greatly improves the operating efficiency. Through the coordinated use of the vertical spring 19 and the horizontal spring 24, the L-shaped clamp arm 15 can fit tightly to the inner wall of the drilling pipe 1, and maintain a stable fixing effect even in a vibration or impact environment. In addition, the overall device has a compact structure and a reasonable design. The connection between the components is firm and reliable, which is convenient for daily maintenance and inspection.

[0027] Furthermore, in this example, Figure 2 、 Figure 3 and Figure 4As shown, the fixing assembly includes a support column 8, a first circular handrail 11 is installed at the upper end of the support column 8, the support column 8 is slidably inserted in the short arc groove 6, and a limited circular block 17 is installed at the lower end of the support column 8, and a resisting spring 16 is sleeved on the support column 8 between the upper end surface of the limited circular block 17 and the cover plate 2, and the lower end surface of the first circular handrail 11 is located at a position on one side of the support column 8 and a directional pulley 22 is installed, and an arc groove 9 is opened on the cover plate 2 at a position corresponding to the directional pulley 22, and the lower end of the cover plate 2 is located at one end of the short arc groove 6 and a first concave mounting block 13 is installed, the top end of the first concave mounting block 13 is fixedly installed on the bottom surface of the cover plate 2, and a first rotating rod is installed on the inner wall of the groove of the first concave mounting block 13, and a mounting rod is rotatably installed on the first rotating rod. The circular ring 14 has an L-shaped clamp arm 15 installed on one side wall of the mounting circular ring 14. The L-shaped clamp arm 15 is installed inverted, and a second concave mounting block 20 is installed on the outer side of the short side top surface of the L-shaped clamp arm 15. A second rotating rod is installed on the inner wall of the groove of the second concave mounting block 20. One end of a vertical guide rod 18 is installed on the second rotating rod. The end of the vertical guide rod 18 is located at the position of the second rotating rod and a circular hole with the same diameter as the second rotating rod is opened. A vertical spring 19 is sleeved on the vertical guide rod 18. The top end of the vertical guide rod 18 is slidably inserted into the bottom of the cover plate 2. The bottom of the cover plate 2 is located at the position of the vertical guide rod 18 and a circular groove with the same diameter as the vertical guide rod 18 is opened. One end of the vertical spring 19 abuts against the side wall of the second rotating rod. The vertical spring 1 The other end of 9 abuts against the bottom surface of the cover plate 2, and a through hole is opened in the middle of the long side of the L-shaped clamping arm 15, and a horizontal guide rod 23 is slidably inserted in the hole. The end of the horizontal guide rod 23 close to the inner wall of the drilling pipe 1 is installed with an arc-shaped stop plate 21, and the end of the horizontal guide rod 23 away from the inner wall of the drilling pipe 1 is installed with a limit ring. A horizontal spring 24 is sleeved on the horizontal guide rod 23, and one end of the horizontal spring 24 abuts on the side wall of the arc-shaped stop plate 21, and the other end of the horizontal spring 24 abuts on the inner wall of the L-shaped clamping arm 15. The support column 8 is slidably inserted in the short arc groove 6 through the limiting round block 17 at its lower end. At the same time, the stop spring 16 is sleeved on the support column 8 and is located between the limiting round block 17 and the cover plate 2, providing a certain elastic support and reset ability for the support column 8. The first circular handrail 11 is installed on the upper end of the support column 8 for easy operation by the user. The directional pulley 22 is installed on the lower end surface of the first circular handrail 11 and slides along the arc groove 9 on the cover plate 2, which helps to maintain stability and guidance when adjusting the position of the support column 8. The L-shaped clamping arm 15 rotates in the first concave mounting block 13 through the mounting ring 14 and the first rotating rod to achieve flexible adjustment of the clamping arm. The vertical guide rod 18 is installed on the L-shaped clamping arm 15 through the second rotating rod and is covered with a vertical spring 19 to provide a certain elastic support for the L-shaped clamping arm 15. The horizontal guide rod 23 is slidably inserted into the hole of the L-shaped clamping arm 15. The arc-shaped support plate 21 and the horizontal spring 24 are respectively installed at both ends of the horizontal guide rod 23 to achieve fixation and buffering of the inner wall of the drilling pipe.When it is necessary to fix the cover plate 2, the user operates the first circular handrail 11 to drive the support column 8 to slide in the short arc groove 6, and through the guiding effect of the directional pulley 22 in the arc groove 9, the upper end surface of the L-shaped clamping arm 15 abuts against the lower end of the limiting round block 17, and the fixed arc-shaped retaining plate 21 fits tightly against the inner wall of the drilling pipe 1. As the L-shaped clamping arm 15 rotates, the arc-shaped retaining plate 21 first contacts the inner wall of the drilling pipe 1 and is subjected to the reaction force of the inner wall of the drilling pipe 1, which causes the horizontal guide rod 23 to slide in the hole of the L-shaped clamping arm 15, and at the same time the horizontal spring 24 is compressed, generating The vertical spring 19 also plays a role in this process. It allows the L-shaped clamp arm 15 to deform elastically when subjected to the reaction force from the inner wall of the drilling pipe 1, thereby absorbing some of the impact force and protecting the fixing assembly and the inner wall of the drilling pipe 1 from damage. When the cover plate 2 needs to be opened, the user can reverse the operation of the first circular handrail 11 to make the bottom end of the limiting block 17 leave the top of the short arm of the L-shaped clamp arm 15. As the limiting block 17 moves away from the top of the short arm of the L-shaped clamp arm 15 and the lock of the L-shaped clamp arm 15 is unlocked, it is only necessary to lift the cover plate 2.

[0028] Furthermore, in this example, Figure 1 and Figure 5As shown, the opening and closing assembly includes an operating circular plate 10, and the top of the operating circular plate 10 is located at the position of the two groups of long arc grooves 5. Connecting columns 7 are installed, and the tops of the two groups of connecting columns 7 are installed with second circular armrests 12. The bottom surface of the operating circular plate 10 is evenly arranged with multiple groups of oblique linear grooves 25. Multiple groups of oblique triangular plates 27 are evenly spaced and installed on one side of the oblique linear grooves 25 on the operating circular plate 10. The number of oblique triangular plates 27 is the same as that of the oblique linear grooves 25. A limiting strip is installed on each group of oblique triangular plates 27 on one side of the operating circular plate 10. The limiting strip is slidably installed in the oblique linear grooves 25. The width of the limiting strip is the same as that of the oblique linear grooves 25. The oblique triangular plates 27 slide in the oblique linear grooves 25 through the limiting strip. , each set of oblique triangular plates 27 is installed with a mounting column 26 on the side wall away from the operating circular plate 10, and the mounting column 26 is cylindrical. A fixed base plate 28 is installed on one side of the oblique triangular plate 27 where the mounting column 26 is installed. A plurality of oblique arc grooves 29 are evenly arranged on the fixed base plate 28. The number of oblique arc grooves 29 is the same as the number of mounting columns 26, and the outer end of each set of mounting columns 26 is slidably inserted into the oblique arc groove 29 at the corresponding position. The other side of the fixed base plate 28 is fixedly mounted on the bottom surface of the circular groove 4. The operating circular plate 10 is above the space in the circular groove 4, and the fixed base plate 28 is fixedly mounted on the bottom surface of the circular groove 4. The connecting column 7 is mounted on the top of the operating circular plate 10 and is located at the position of the two sets of long arc grooves 5. The second circular handrail 1 2 is installed on the top of the connecting column 7, which is convenient for the user to operate. The oblique linear grooves 25 are evenly arranged on the bottom surface of the operating circular plate 10, and the oblique triangular plates 27 are evenly spaced and installed on the operating circular plate 10 and correspond to the oblique linear grooves 25. The limit strips are installed on each set of oblique triangular plates 27 and slidably installed in the corresponding oblique linear grooves 25 to ensure that the oblique triangular plates 27 can slide along the oblique linear grooves 25. The mounting column 26 is installed on the side wall of the oblique triangular plate 27 away from the operating circular plate 10 and is cylindrical. At the same time, it is slidably inserted into the oblique arc groove 29 at the corresponding position on the fixed bottom plate 28. When the user needs to open the opening and closing component, by holding the second circular armrest 12 and applying a rotational force, the operating circular plate 1 is driven. 0 rotation, as the operating circular plate 10 rotates, the oblique triangular plate 27 is restricted by the fixed bottom plate 28 and cannot rotate with the operating circular plate 10, but slides in the oblique linear groove 25 through the limit bar. Due to the oblique design of the oblique linear groove 25 and the oblique triangular plate 27, when the operating circular plate 10 rotates, the oblique triangular plate 27 will slide along the oblique linear groove 25 and gradually move away from the center of the operating circular plate 10, while driving the mounting post 26 to slide in the oblique arc groove 29. This sliding process causes the front end of the oblique triangular plate 27 of the opening and closing assembly to gradually expand, thereby achieving the opening and closing effect. When the operating circular plate 10 rotates to a predetermined position, the oblique triangular plate 27 and the mounting post 26 will reach the ends of the oblique linear groove 25 and the oblique arc groove 29.At this point, the opening and closing assembly is fully open. When the user needs to close the opening and closing assembly, the second circular armrest 12 is rotated in the opposite direction, driving the operating circular plate 10 to rotate in the opposite direction. As the operating circular plate 10 rotates in the opposite direction, the oblique triangular plate 27 slides along the oblique linear groove 25 again, and the front end of the oblique triangular plate 27 gradually approaches the center of the operating circular plate 10. At the same time, the mounting post 26 also slides in the oblique arc groove 29 and gradually returns to its initial position. When the operating circular plate 10 rotates back to its initial position, the oblique triangular plate 27 and the mounting post 26 also return to their initial state. At this time, the opening and closing assembly is fully closed.

[0029] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0030] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A device for preventing falling objects at the wellhead of an oil drilling well, characterized in that: include: A drilling pipe (1), the drilling pipe (1) is set in the soil, a cover plate (2) is installed directly above the drilling pipe (1), a circular hole (3) is opened in the middle of the cover plate (2), a circular groove (4) is opened in the middle of the inner wall of the circular hole (3), two groups of long arc grooves (5) are opened on the cover plate (2) near the edge of the circular hole (3), and two groups of short arc grooves (6) are opened between the outer edge of the cover plate (2) and the long arc groove (5); A fixing assembly, the fixing assembly being arranged below the cover plate (2), and the fixing assembly being used to fix the cover plate (2) on the inner wall of the drilling pipe (1); An opening and closing component is arranged in the circular groove (4) opened in the middle of the inner wall of the circular hole (3), and the opening and closing component is used to facilitate the insertion of the drill bit.

2. The oil drilling wellhead falling object prevention device according to claim 1, characterized in that: The fixing assembly includes a support column (8), the upper end of the support column (8) is equipped with a first circular handrail (11), the support column (8) is slidably inserted in the short arc groove (6), and the lower end of the support column (8) is equipped with a limiting circular block (17), and the support column (8) between the upper end surface of the limiting circular block (17) and the cover plate (2) is provided with a resisting spring (16), the lower end surface of the first circular handrail (11) is located on one side of the support column (8) and is equipped with a directional pulley (22), and the cover plate (2) is provided with an arc groove (9) at a position corresponding to the directional pulley (22), and a first concave mounting block (13) is installed at a position at the lower end of the cover plate (2) at one end of the short arc groove (6), the top end of the first concave mounting block (13) is fixedly mounted on the bottom surface of the cover plate (2), a first rotating rod is installed on the inner wall of the groove of the first concave mounting block (13), a mounting ring (14) is rotatably mounted on the first rotating rod, and an L-shaped clamping arm (15) is installed on one side wall of the mounting ring (14).

3. The oil drilling wellhead falling object prevention device according to claim 2, characterized in that: The L-shaped clamp arm (15) is installed in an inverted manner, and a second concave mounting block (20) is installed on the outer side of the top surface of the short side of the L-shaped clamp arm (15), a second rotating rod is installed on the inner wall of the groove of the second concave mounting block (20), and one end of a vertical guide rod (18) is installed on the second rotating rod. The end of the vertical guide rod (18) is located at the position of the second rotating rod and is provided with a circular hole with the same diameter as the second rotating rod, and a vertical spring (19) is sleeved on the vertical guide rod (18).

4. The oil drilling wellhead falling object prevention device according to claim 3, characterized in that: The top end of the vertical guide rod (18) is slidably inserted into the bottom of the cover plate (2); the bottom of the cover plate (2) is located at the position of the vertical guide rod (18) and is provided with a circular groove having the same diameter as the vertical guide rod (18); one end of the vertical spring (19) abuts against the side wall of the second rotating rod, and the other end of the vertical spring (19) abuts against the bottom surface of the cover plate (2).

5. The oil drilling wellhead falling object prevention device according to claim 4, characterized in that: A through hole is provided in the middle of the long side of the L-shaped clamp arm (15), and a horizontal guide rod (23) is slidably inserted into the hole. An arc-shaped retaining plate (21) is installed at one end of the horizontal guide rod (23) close to the inner wall of the drilling pipe (1), and a limiting ring is installed at one end of the horizontal guide rod (23) away from the inner wall of the drilling pipe (1). A horizontal spring (24) is sleeved on the horizontal guide rod (23), one end of the horizontal spring (24) abuts against the side wall of the arc-shaped retaining plate (21), and the other end of the horizontal spring (24) abuts against the inner wall of the L-shaped clamp arm (15).

6. The oil drilling wellhead falling object prevention device according to claim 1, characterized in that: The opening and closing assembly comprises an operating circular plate (10), the top of the operating circular plate (10) is provided with connecting columns (7) at the positions of the two groups of the long arc grooves (5), and the tops of the two groups of the connecting columns (7) are provided with second circular handrails (12), the bottom surface of the operating circular plate (10) is provided with multiple groups of oblique linear grooves (25) arranged evenly in a row, multiple groups of oblique triangular plates (27) are evenly spaced and provided on one side of the oblique linear grooves (25) on the operating circular plate (10), the number of the oblique triangular plates (27) is the same as the number of the oblique linear grooves (25), and a limiting strip is provided on each group of the oblique triangular plates (27) located on one side of the operating circular plate (10), the limiting strip is slidably provided in the oblique linear grooves (25), the width of the limiting strip is the same as the width of the oblique linear grooves (25), and the oblique triangular plates (27) slide in the oblique linear grooves (25) through the limiting strip.

7. The oil drilling wellhead falling object prevention device according to claim 6, characterized in that: A mounting post (26) is mounted on the side wall of each group of the oblique triangular plates (27) away from the operating circular plate (10), and the mounting post (26) is cylindrical. A fixed base plate (28) is mounted on the side of the oblique triangular plates (27) on which the mounting post (26) is mounted, and a plurality of groups of oblique arc grooves (29) are evenly arranged in a row on the fixed base plate (28). The number of the oblique arc grooves (29) is the same as the number of the mounting posts (26), and the outer end of each group of the mounting posts (26) is slidably inserted into the oblique arc groove (29) at the corresponding position, and the other side of the fixed base plate (28) is fixedly mounted on the bottom surface of the circular groove (4).

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