A back reaming structure for a down-the-hole drill bit

Abstract

The utility model provides a follow the pipe structure for down -the -hole drill, including the sleeve pipe, detachable installation in the connecting sleeve of sleeve pipe top, is equipped with a plurality of strip keys on the sleeve pipe inner wall and the surface key groove of down -the -hole drill corresponds, is equipped with at least one pin hole on the sleeve pipe surface and the snap spring groove top of down -the -hole drill corresponds, the movable pin hole is equipped with the pin post, when the sleeve pipe is covered on down -the -hole drill, the pin post end part is placed in the lower side place in the snap spring groove, the utility model discloses when using, the inner chamber of sleeve pipe is straight cylinder, need not processing and place the special groove of snap spring, has omitted the processing step, only needs to drill a few pin holes for installing pin post on the side of sleeve pipe, compared with the mode that the current pipe shoe passes through snap spring and clamps the main drill handle, the processing difficulty and step greatly reduce.

Description

Technical Field

[0001] This utility model relates to the field of tube shoe technology, specifically a follow tube structure for down-the-hole drill bits. Background Technology

[0002] When installing a down-the-hole (DH) drill bit, first, a matching tube shoe needs to be fitted onto the drill shank of the DH drill bit. Then, the tube shoe is threaded onto the drill rod to complete the installation. Existing DH drill bit structures are as follows: Figure 1 As shown in the down-the-hole drill bit 11, a retaining ring groove 12 is provided at the top of the drill shank. During installation, the tube shoe is fitted onto the drill shank, allowing the tube shoe to be keyed to the drill shank, as shown in the figure. Figure 5 As shown, two semi-circular retaining rings 6 are then placed inside the top of the tube shoe to limit the drill bit and prevent it from falling out of the tube shoe.

[0003] A slot specifically for housing the retaining spring 6 needs to be provided inside the top of the boot (e.g. Figure 4 (As indicated by the middle arrow A), and the retaining ring 6 needs to be machined into a specific shape, which involves a precise and multi-step machining process, adding to the production cost. Therefore, we propose a casing structure for down-the-hole drill bits. Utility Model Content

[0004] This invention provides a casing structure for down-the-hole drill bits, which has the advantages of convenient installation and easy processing, and solves the problems mentioned in the background art.

[0005] The technical solution of this utility model is implemented as follows: a casing structure for down-the-hole drill bits is designed, including a casing, the top of which is detachably installed in a connecting sleeve. The inner wall of the casing is provided with multiple bar keys corresponding to the keyways on the surface of the down-the-hole drill bit. The surface of the casing is provided with at least one pin hole corresponding to the snap ring groove on the top of the down-the-hole drill bit. A pin is movably provided in the pin hole. When the casing is fitted onto the down-the-hole drill bit, the end of the pin is positioned slightly below the snap ring groove.

[0006] Preferably, the outer surface of the sleeve is stepped, and an external thread is provided on its top surface, while an internal thread corresponding to the external thread is provided inside the connecting sleeve.

[0007] Preferably, the bottom surface of the sleeve is provided with at least two symmetrical planar grooves.

[0008] Preferably, the top of the connecting sleeve is connected to the drill pipe.

[0009] Preferably, the number of pin holes is at least two and they are symmetrically distributed.

[0010] Compared with the prior art, this utility model is convenient to install by inserting the pin into the pin hole. When removing the sleeve, the pin can be directly removed to detach the sleeve from the drill shank. At the same time, the drill shank is limited by at least two pins, and the limiting force is strong, which can effectively prevent the drill shank from coming off. Most importantly, the inner cavity of the sleeve is cylindrical, eliminating the need to process a special groove for placing the retaining spring, thus omitting the processing steps. Only a few pin holes for installing the pin need to be drilled on the side of the sleeve. Compared with the existing method of using retaining springs to hold the drill shank, the processing difficulty and steps are greatly reduced. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a three-dimensional structural diagram of the present invention. Figure 1 .

[0013] Figure 2 This is a three-dimensional structural diagram of the present invention. Figure 2 .

[0014] Figure 3 This is a cross-sectional view of the present invention.

[0015] Figure 4 Schematic diagram of the existing tube shoe structure Figure 1 .

[0016] Figure 5 Schematic diagram of the existing tube shoe structure Figure 2 .

[0017] In the diagram: 1. Drill rod; 2. Connecting sleeve; 3. Casing; 4. Flat groove; 5. Strip key; 6. Snap ring; 7. Pin hole; 8. Pin; 9. External thread; 10. Internal thread; 11. Down-the-hole drill bit; 12. Snap ring groove. Detailed Implementation

[0018] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] Reference Figures 1 to 3This utility model provides a technical solution: a casing structure for down-the-hole drill bits, including a casing 3 (commonly called a casing shoe), the top of which is detachably installed in a connecting sleeve 2, such as... Figure 1 and Figure 2 As shown, specifically, the top surface of the sleeve 3 is provided with an external thread 9, and the connecting sleeve 2 is provided with an internal thread 10 corresponding to the external thread 9. The top thread of the sleeve 3 is installed in the connecting sleeve 2. The outer surface of the sleeve 3 is stepped. The external thread 9 is provided on the stepped surface of the sleeve 3, and the step below the sleeve 3 is used to cooperate with the connecting sleeve 2 to play a limiting role.

[0020] Furthermore, it is necessary to explain the actual down-the-hole drill bits, such as... Figure 1 As shown, the top of the drill shank of the down-the-hole drill bit is provided with a snap ring groove 12, and multiple keyways are provided on the surface of the drill shank below the snap ring groove 12. Corresponding to the keyway, multiple bar keys 5 are provided on the inner wall of the sleeve 3. The bar keys 5 correspond to the keyway on the surface of the down-the-hole drill bit 11. When the sleeve 3 is fitted onto the down-the-hole drill bit 11, the bar keys 5 are placed in the keyway, so that the down-the-hole drill bit 11 can only move along the axial direction of the sleeve 3 and cannot rotate. To prevent the down-the-hole drill bit 11 from dislodging from the casing 3, at least one pin hole 7 is provided on the surface of the casing 3, corresponding to the retaining groove 12 at the top of the down-the-hole drill bit 11. The pin hole 7 is located at the external thread 9, and it does not affect the continuity of the external thread 9. Furthermore, the position of the pin hole 7 should be offset from the bar key 5 to avoid penetrating the bar key. There are at least two pin holes 7, symmetrically distributed, and each pin hole 7 contains a movable pin 8. When the casing 3 is fitted onto the down-the-hole drill bit 11, as... Figure 3 As shown, the end of the pin 8 is positioned slightly below the snap ring groove 12, which maximizes the movement distance of the down-the-hole drill bit 11 when it moves up and down. It should be noted that the clearance fit between the pin 8 and the inner wall of the snap ring groove 12 allows for a certain amount of play between the inner wall of the snap ring groove 12 and the end of the pin 8, preventing hard friction between the pin 8 and the snap ring groove 12. Moreover, the insertion of the pin 8 into the pin hole 7 not only makes installation convenient, but also allows the sleeve 3 to be removed directly by taking out the pin 8 when removing the sleeve 3, thus removing the sleeve 3 from the drill shank. Furthermore, the drill shank is limited by at least two pins 8, with a strong limiting force, which can effectively prevent the drill shank from coming out. Most notably, the inner cavity of the sleeve 3 is cylindrical, eliminating the need for machining a special groove for placing the retaining spring 6, thus omitting machining steps. Moreover, it is only necessary to drill a few pin holes 7 on the side of the sleeve 3 for installing the pin 8. Compared to the existing method of using the retaining spring 6 to hold the main drill shank, the pin holes 7 are directly drilled on the surface of the sleeve 3, and then the pin 8 is placed in the pin holes 7, which greatly reduces the machining difficulty and steps.

[0021] Furthermore, at least two symmetrical planar grooves 4 can be provided on the bottom surface of the casing 3. The planar grooves 4 facilitate the installation of the casing 3 by tightening the shoe and drill shank with a wrench, greatly reducing the processing difficulty and steps.

[0022] Furthermore, it should be noted that the top of the connecting sleeve 2 is connected to the drill rod 1. It should be said that the connecting sleeve 2 and the drill rod 1 are an integral structure. The drill rod 1 is connected to the power device, thereby driving the drill rod 1 to rotate.

[0023] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A casing structure for a down-the-hole drill bit, comprising a casing (3), the top of which is detachably installed in a connecting sleeve (2), and the inner wall of the casing (3) having multiple bar keys (5) corresponding to the keyways on the surface of the down-the-hole drill bit (11), characterized in that, The casing (3) has at least one pin hole (7) on its surface that corresponds to the snap ring groove (12) on the top of the downhole drill bit (11). A pin (8) is provided in the pin hole (7). When the sleeve (3) is fitted onto the downhole drill bit (11), the end of the pin (8) is positioned slightly below the snap ring groove (12).

2. The casing structure for down-the-hole drill bits as described in claim 1, characterized in that, The outer surface of the sleeve (3) is stepped, and an external thread (9) is provided on its top surface. The inner thread (10) corresponding to the external thread (9) is provided inside the connecting sleeve (2).

3. The casing structure for down-the-hole drill bits as described in claim 2, characterized in that, The bottom surface of the sleeve (3) is provided with at least two symmetrical planar grooves (4).

4. The casing structure for down-the-hole drill bits as described in claim 1, characterized in that, The top of the connecting sleeve (2) is connected to the drill rod (1).

5. The casing structure for down-the-hole drill bits as described in claim 3 or 4, characterized in that, The number of pin holes (7) is at least two and they are symmetrically distributed.

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