Patent ID: 12221859

REFERENCE NUMERALS

1. base;11. fork;12. shift fork;13. pin;14. support plate;15. pin hole;16. key pin;2. steel ball seat;20. guide ramp;21. upper steel ball seat;22. lower steel ball seat;23. outer annular groove;3. steel ball frame;31. limit hole;311. upper limit hole;312. lower limit hole;313. protruding ring;32. flange;4. steel ball;5. drill pipe.

DESCRIPTION OF THE EMBODIMENTS

The present invention is further described in combination with the accompanying drawings and specific embodiments.

As shown inFIGS.1to11, a ball-clamp type fall arrester for a drill pipe includes a base1and a steel ball seat2which is arranged in the base1. A liftable steel ball frame3is arranged in the steel ball seat2. A side wall of the steel ball frame3is provided with a plurality of limit holes31. An inner wall of the steel ball seat2is provided with a guide ramp20. Steel balls4are arranged in the limit holes31and are radially movable. When the steel ball frame3is lifted or lowered, the radial positions of the steel balls4in the limit holes31are positioned by the guide ramp20.

At least one circumference of the steel ball frame3is provided with several steel balls4arranged at equal intervals. The inner wall of the steel ball seat2forms the guide ramp20of an inverted conical shape.

The steel balls4and the guide ramp20of the steel ball seat2movably cooperate and resume a clamped state or an unclamped state. The steel ball frame3is positioned in the steel ball seat2. The side wall of the steel ball frame3is provided with the limit holes31, in which movable steel balls4are arranged. The steel balls4are lifted or lowered with the limit holes31during the axial upward or downward movement of the steel ball seat3. When the steel balls4are lowered, they come into contact with the guide ramp20of the inner wall of the steel ball seat2. By the contact cooperation with the inverted conical inner wall of the steel ball seat2, which narrows from top to bottom, the steel balls4move radially inwardly, and they partly pass through the limit holes31and then abut an outer wall of the drill pipe5that passes through the steel ball frame3, clamping the drill pipe5to prevent it from falling. Due to the cooperation of the drill pipe5and the guide ramp20of the inner wall of the steel ball seat2, the steel balls4are in the clamped state when moving to the bottom of the steel ball seat2, and in the unclamped state when moving to the top of the steel ball seat2.

In the present embodiment, the steel ball seat2includes an upper steel ball seat21and a lower steel ball seat22having identical structures with a wide top and a narrow bottom. The limit holes31includes upper limit holes312and lower limit holes312provided on the steel ball frame3, wherein the upper limit holes311is movably positioned in the upper steel ball seat21, and the lower limit hole312is movably positioned in the lower steel ball seat22. The upper steel ball seat21and the lower steel ball seat22have identical structures with an inverted conical guide ramp20that is wide at the top and narrow at the bottom. When installed in the base1, the upper steel ball seat21is located above the lower steel ball seat22, with the larger diameter ends of both facing upwards. The limit holes31of the steel ball frame3are arranged in two rows, i.e., the upper limit holes311and the lower limit holes312. The axial positions of the upper limit holes311are limited by the axial length of the upper steel ball seat21, and the axial positions of the lower limit holes312are limited by the axial length of the lower steel ball seat22. When raising the drill pipe, the steel ball seat3is lifted axially, and the steel balls4move in the upper limit holes311and the lower limit holes312axially and outwardly. When the steel balls4move to the larger diameter ends of the upper steel ball seat21and the lower steel ball seat22, the steel balls4are separated from the drill pipe5and resume in the unclamped state, and thus the drill pipe5can be taken out from the steel ball frame3. During the axial upward movements of the steel balls4, when the steel balls4in the lower limit holes312move to the bottom of the upper steel ball seat21, they will abut against the bottom of the upper steel ball seat21to prevent the steel ball frame3from continuing moving out axially, and thus to prevent the steel ball frame3and the steel balls4from moving out of the base1which plays a role in limiting and protecting the steel ball frame3from moving out of the steel ball seat2. When the drill pipe5falls, it drives the steel balls4and the steel ball frame3to move axially downwardly, and the steel balls4contact with the inverted conical inner walls of the upper steel ball seat21and the lower steel ball seat22. During the downward movements, the steel balls4keep clamping the drill pipe5in cooperation with the inverted conical surface inner wall of the upper steel ball seat21and the lower steel ball seat22, such that the steel balls4are in the clamped state, and thus the drill pipe5is clamped.

The inner sides of upper limit holes311and lower limit holes312are respectively provided with protruding rings313to prevent the steel balls4from moving out. The inner diameter of the protruding rings313is smaller than that of the steel balls4. In the state without the drill pipe5, the steel ball frame3will fall to the bottom of the steel ball seat2due to its own gravity, and the steel balls4will move radially inward along the limit holes31. The protruding rings313can prevent the steel balls4from moving out of the limit holes31and falling into the drill hole.

A side wall of the base1is provided with a rotatable fork11. The top of the steel ball frame3is provided with a flange32extending radially outwardly. The front end of the fork11is provided with a shift fork12, which is clamped at the steel ball frame3and abuts against the lower side of the flange32. Specifically, the side wall of the base1extends outwardly to form a support plate14, and the fork11is rotatably connected to the support plate14through a pin13. When raising the drill pipe, the fork11is depressed downwards, with the pin13serving as a fulcrum, and a front end of the fork11will move upwards. The steel ball frame3can be lifted through the shift fork12clamped under the flange32. When the steel ball frame3is lifted, it will drive the steel balls4to move axially upwardly, and the steel balls4will gradually move to the inner walls with a larger inner diameter of the upper steel ball seat21and the lower steel ball seat22. At this time, the upper steel ball seat21and the lower steel ball seat22have no restriction on the steel balls4. Thus, the steel balls4are in the unclamped state, the drill pipe5is unclamped and it can be taken out of the steel ball frame3.

The side wall of the base1is provided with a pin hole15. An outer wall of the steel ball seat2is provided with an outer annular groove23. The pin hole15is inserted with a key pin16, and the end of the key pin16is inserted into the outer annular groove23. During assembly, the lower steel ball seat22is first placed into the base1, and then the upper steel ball seat21. The upper steel ball seat21is arranged above the lower steel ball seat22. The key pin16is tightly screwed in the pin hole15, and the key pin16is fastened on the upper steel ball seat21, thus the upper steel ball seat21and the lower steel ball seat22can be fixed in the base1simultaneously. The key pin16can also be inserted into the outer annular groove23of the upper steel ball seat21and the lower steel ball seat22simultaneously, locking the upper steel ball seat21and the lower steel ball seat22. In other embodiments, the steel ball seat2and the base1can also be assembled through thread connection.

During a specific implementation of the present invention, as shown inFIG.10, which is a schematic cross-sectional structural view of an embodiment of the present invention in a clamped state with a specific implementation, the fall arrester is mounted around an outer circumference of the drill pipe5. Under normal conditions, the steel ball frame3is located below the steel ball seat2due to its own gravity and thus contacts the drill pipe5. The steel balls4maintain point contact with the drill pipe5, and the steel balls4can rotatably support the outer wall of the drill pipe5during the normal drilling of the drill pipe5.

When a drill-falling occurs, the drill pipe5falls, and it keeps contact with the steel balls4and drives the steel balls4as well as the steel ball frame3to fall, and the steel ball frame3axially moves downwardly from the original position. During the moving process, the steel balls4are limited by the gradually narrowed guide ramps20of the upper steel ball seat21and the lower steel ball seat22, so that the steel balls4continue moving radially towards the outer wall of the drill pipe5in the process moving downwardly. During the downward and radially inward movement of the steel balls4, the radial force of the steel balls4contacting and clamping the drill pipe5gradually increases until the drill pipe5is locked. By the cooperation of the steel balls4and the steel ball seat2, the purpose of clamping the drill pipe5is achieved, which can effectively prevent the drill pipe5from suddenly falling, and has high safe performance in use.

As shown inFIG.11, shown is a schematic cross-sectional structural view of an embodiment of the present invention in an unclamped state with a specific implementation. When raising the drill pipe, the fork11is depressed downwardly, and the shift fork12of the fork11moves up to lift the steel ball frame3upwardly. During the axial upward movement of steel ball frame3, it drives the steel balls4to move axially upwardly. During the upward movement of the steel balls4, they gradually separate from the guide ramps20of the inner walls of the upper steel ball seat21and the lower steel ball seat22. The steel balls4in the lower limit holes312move upwardly until contacting the bottom of the upper steel ball seat21. The upper steel ball seat21limits the steel balls4and the steel ball frame3from moving outwardly, to prevent the steel ball frame3from moving out of the base1. During the upward movements of the steel balls4, the clamping force on the drill pipe5is gradually reduced. When the steel balls4release the drill pipe5, the drill pipe5can be taken out of the steel ball frame3.

In summary, the present invention has been made into actual samples and undergone multiple usage tests as the description and illustrations describe. From the results of the usage tests, it can be proven that the present invention can achieve its intended purpose, and its practical value is beyond doubt. The above-mentioned embodiments are only used to illustrate the present invention for convenience, and are not intended to limit the present invention in any form. Any equivalent embodiments obtained by those of ordinary skill in the art by partially modifying or changing the technical content disclosed in the present invention without departing from the technical features of the disclosure all fall within the scope of the disclosure.