A telescopic down-the-hole drill bit guide device

Abstract

This utility model relates to a telescopic down-the-hole drill bit guide device, belonging to the technical field of drill bit auxiliary structures. The telescopic down-the-hole drill bit guide device includes: a guide bushing and a locking mechanism. The guide bushing has a chip removal groove on its side end, and ball bearings staggered with the chip removal groove are embedded in the side end of the guide bushing. The top of the guide bushing has a countersunk hole, and the interior of the guide bushing has a positioning groove communicating with the countersunk hole. The locking mechanism includes a bolt inserted into the countersunk hole, and the side end of the bolt head has an installation cavity communicating with the positioning groove. The locking block and the positioning groove are always positioned on the side of the bolt facing away from the axis of the guide bushing, ensuring that centrifugal force pushes the locking block outward during drill bit rotation, allowing it to penetrate deeper into the positioning groove and enhancing the bolt locking effect. This dynamic self-reinforcing mechanism effectively prevents bolt loosening, eliminating the need for adhesive injection to prevent loosening and removing residual adhesive from the source.

Description

Technical Field

[0001] This utility model relates to the field of drill bit auxiliary structure technology, and in particular to a telescopic down-the-hole drill bit guide device. Background Technology

[0002] Telescopic down-the-hole (DHH) bits achieve axial extension and retraction adjustment of the bit head through internal mechanical structures (such as springs and hydraulic devices). They can dynamically adjust the extension length according to rock hardness or drilling resistance, optimizing drilling efficiency and reducing the risk of stuck drill bit, while protecting the drill pipe from impact damage.

[0003] Currently, this drill bit commonly uses bolted guide bushings. To prevent the bolts from loosening, maintenance personnel often inject adhesive into the threaded holes, but cleaning residual adhesive during disassembly and assembly is time-consuming, reducing the efficiency of bushing replacement. Utility Model Content

[0004] Therefore, it is necessary to provide a telescopic down-the-hole drill bit guide device to address the problem that the existing anti-loosening design telescopic down-the-hole drill bit guide device is cumbersome to replace and maintain, and inconvenient to replace.

[0005] A telescopic down-the-hole drill bit guide device includes: a guide bushing and a locking mechanism. The guide bushing has a chip removal groove on its side end, and ball bearings that are staggered with the chip removal groove are embedded in the side end of the guide bushing. The guide bushing has a countersunk hole on its top, and a positioning groove communicating with the countersunk hole is formed inside the guide bushing.

[0006] In one embodiment, the locking mechanism includes a bolt inserted into the countersunk hole, and a mounting cavity communicating with a positioning groove is provided on the side end of the bolt head. A locking block that is inserted into the positioning groove is slidably connected inside the mounting cavity. The locking block and the positioning groove are always located on the side of the bolt facing away from the axis of the guide bushing.

[0007] In one embodiment, a spring is fixedly connected to one end of the locking block facing away from the positioning groove, and one end of the spring contacts the mounting cavity.

[0008] In one embodiment, the locking block is disposed in a local cross-sectional shape of an isosceles triangle in the positioning groove, and one end of the locking block disposed inside the positioning groove has rounded corners.

[0009] In one embodiment, the horizontal depth of the positioning groove is less than the horizontal length of the locking block, and the horizontal depth of the positioning groove is greater than the local horizontal length of the locking block, which has a local cross-sectional shape of an isosceles triangle.

[0010] In one embodiment, the locking block is cylindrical in shape in the portion outside the positioning groove, and conical in shape in the portion inside the positioning groove.

[0011] In one embodiment, the connection between the positioning groove and the countersunk hole is beveled.

[0012] In one embodiment, an anti-detachment block is slidably connected inside the mounting cavity, and the two ends of the anti-detachment block are respectively fixedly connected to a locking block and a spring.

[0013] In one embodiment, the vertical cross-sectional shape of the mounting cavity is convex, and the vertical cross-sectional height of the anti-detachment block is greater than the vertical cross-sectional inner diameter of the mounting cavity opening.

[0014] Beneficial effects

[0015] The aforementioned telescopic down-the-hole drill bit guide device has a locking block and a positioning groove always positioned on the side of the bolt facing away from the guide bushing axis. This ensures that when the drill bit rotates, centrifugal force pushes the locking block outward to slide deeper into the positioning groove, enhancing the bolt locking effect. This dynamic self-reinforcing mechanism effectively prevents the bolt from loosening, eliminating the need to rely on adhesive injection for anti-loosening and removing residual adhesive cleaning problems at the source.

[0016] The spring is fixedly connected to the end of the locking block facing away from the positioning groove and provides initial preload within the mounting cavity. When the machine stops, the spring automatically pushes the locking block back into the mounting cavity, releasing the lock from the positioning groove and allowing the bolts to be easily removed. This design eliminates the need for cleaning residual adhesive and significantly improves the efficiency of guide bushing replacement. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is an assembly diagram of the overall structure and telescopic down-the-hole drill bit in this utility model;

[0019] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 3 This is a cross-sectional view of the overall structure of this utility model;

[0021] Figure 4 for Figure 3 Enlarged view of A in the middle;

[0022] Figure 5 This is an exploded view of the locking mechanism in this utility model.

[0023] Figure label:

[0024] 100. Guide bushing; 110. Chip removal groove; 120. Countersunk hole; 130. Positioning groove; 200. Ball bearing; 300. Locking mechanism; 310. Bolt; 311. Mounting cavity; 320. Locking block; 330. Spring; 340. Anti-detachment block. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0026] The following is combined Figure 1 - Figure 5 This invention describes a telescopic down-the-hole drill bit guide device.

[0027] In one embodiment, a telescopic down-the-hole drill bit guiding device includes: a guide bushing 100 and a locking mechanism 300. The guide bushing 100 has a chip removal groove 110 at its side end, and ball bearings 200, staggered with the chip removal groove 110, are embedded in the side end of the guide bushing 100. A countersunk hole 120 is formed at the top of the guide bushing 100, and a positioning groove 130 communicating with the countersunk hole 120 is formed inside the guide bushing 100. The design of the chip removal groove 110 and the ball bearings 200 optimizes chip removal efficiency and guiding performance during drilling. The countersunk hole 120 and the positioning groove 130 provide a mounting base for the locking mechanism 300, creating conditions for subsequent glue-free disassembly and anti-loosening locking.

[0028] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the locking mechanism 300 includes a bolt 310 inserted into the countersunk hole 120. The bolt 310 has a mounting cavity 311 at its head end that communicates with the positioning groove 130. A locking block 320, which is inserted into the positioning groove 130, is slidably connected inside the mounting cavity 311. The locking block 320 and the positioning groove 130 are always positioned on the side of the bolt 310 facing away from the axis of the guide bushing 100. This arrangement ensures that when the drill bit rotates, centrifugal force can effectively act on the locking block 320, pushing it outward to enhance the locking effect. During the manufacturing of the bolt 310, the designer can design the mounting cavity 311 as a horizontally convex hole, then insert the locking block 320, the anti-disengagement block 340, and the spring 330 through the larger inner diameter opening of the mounting cavity 311, and then seal and close the larger inner diameter opening of the mounting cavity 311 by means of hot-melt welding or similar methods.

[0029] like Figure 3 , Figure 4 and Figure 5 As shown, a spring 330 is fixedly connected to one end of the locking block 320 facing away from the positioning groove 130, and one end of the spring 330 contacts the mounting cavity 311. The spring 330 provides initial preload in the non-working state, keeping the locking block 320 in contact with the positioning groove 130 or easily reset, and automatically unlocking when the machine stops, simplifying the disassembly process. The local cross-sectional shape of the locking block 320 within the positioning groove 130 is an isosceles triangle, and one end of the locking block 320 inside the positioning groove 130 has rounded corners. The isosceles triangular cross-section provides a reliable self-locking wedge surface, significantly enhancing the anti-loosening capability, while the rounded corner design effectively reduces the frictional resistance when the locking block 320 slides within the positioning groove 130, making locking and unlocking actions smoother. The horizontal depth of the positioning groove 130 is less than the horizontal length of the locking block 320, and the horizontal depth of the positioning groove 130 is greater than the local horizontal length of the isosceles triangular cross-sectional shape of the locking block 320. This depth design precisely ensures that the isosceles triangular portion of the locking block 320 can be fully embedded into the positioning groove 130 for effective locking. Simultaneously, its overall length constraint prevents over-embedding and jamming, and ensures smooth retraction into the mounting cavity 311 during unlocking. The external portion of the locking block 320 in the positioning groove 130 has a cylindrical shape, while the internal portion has a conical cross-section. The external cylindrical portion facilitates smooth sliding under centrifugal force, while the internal conical (or isosceles triangular) cross-section optimizes the wedging fit with the positioning groove 130, further enhancing the reliability of dynamic locking. The connection between the positioning groove 130 and the countersunk hole 120 is chamfered. This chamfer guides the conical end of the locking block 320 smoothly into the positioning groove 130 during installation and assists the locking block 320 in overcoming friction and smoothly exiting during disassembly, greatly facilitating the replacement of the guide bushing 100.

[0030] like Figure 3 , Figure 4 and Figure 5 As shown, an anti-detachment block 340 is slidably connected inside the mounting cavity 311. Both ends of the anti-detachment block 340 are fixedly connected to the locking block 320 and the spring 330, respectively. The anti-detachment block 340 connects the locking block 320 and the spring 330 into a single assembly, preventing them from loosening and falling out of the mounting cavity 311 during disassembly, assembly, or high-speed rotation, thus improving the overall reliability and service life of the locking mechanism 300. The vertical cross-sectional shape of the mounting cavity 311 is laterally convex, and the vertical cross-sectional height of the anti-detachment block 340 is greater than the vertical cross-sectional inner diameter of the opening of the mounting cavity 311. This structural design creates a physical limit, ensuring that the anti-detachment block 340, along with the locking block 320 and the spring 330, is always constrained inside the mounting cavity 311, and will not accidentally fall off even under strong vibration or centrifugal force, ensuring the continuous effectiveness of the locking function.

[0031] In this embodiment, during disassembly, simply loosen and pull upwards the bolt 310. As the bolt 310 moves, the spring 330 inside its mounting cavity 311 pushes the locking block 320 back from the positioning groove 130 of the guide bushing 100. The end of the locking block 320 that engages with the positioning groove 130 has a rounded isosceles triangular cross-section, and the entrance to the positioning groove 130 is designed with an angle; the two work together to ensure that the locking block 320 exits smoothly. When the bolt 310 is completely removed, the anti-dislodgement block 340 on it effectively prevents the locking block 320 and the spring 330 from falling out of the mounting cavity 311. After removing the old guide bushing 100 with the chip removal groove 110 and the embedded ball bearing 200, install the new guide bushing 100. Insert the assembled locking mechanism 300 into the countersunk hole 120 at the top of the new guide bushing 100 and tighten the bolt 310. During tightening, the inclined surface of the side wall of the positioning groove 130 presses against the rounded isosceles triangular cross-section of the locking block 320, forcing it to compress the spring 330 and slide inward toward the mounting cavity 311. When the bolt 310 is tightened to the correct position, the spring 330 immediately pushes the locking block 320 into the positioning groove 130. The horizontal depth design of the positioning groove 130 ensures that the isosceles triangular cross-section of the locking block 320 can reliably engage to complete the mechanical locking process. No glue is required throughout the process, significantly improving replacement efficiency.

[0032] Working principle: When the drill bit rotates at high speed, the resulting centrifugal force acts on the locking block 320, which is located on a cylindrical portion outside the positioning groove 130. This force pushes the locking block 320 to slide outward along the mounting cavity 311 of the bolt 310, compressing the spring 330. This displacement forces the conical end of the locking block 320, located inside the positioning groove 130, to wed deeper into the positioning groove 130 of the guide bushing 100. The beveled angle at the entrance of the positioning groove 130 helps guide the wedging. The horizontal depth of the positioning groove 130 is less than the overall horizontal length of the locking block 320 but greater than the horizontal length of its conical portion, ensuring effective and reliable wedge locking. The anti-disengagement block 340 inside the mounting cavity 311 prevents the component from disengaging during high-speed rotation. The higher the drill bit speed, the greater the centrifugal force generated, and the stronger the wedging force pushing the locking block 320, achieving a self-reinforcing "tightening with rotation" dynamic anti-loosening. After the centrifugal force disappears when the machine stops, the spring 330 automatically resets and the locking block 320 unlocks. This mechanism cleverly utilizes the rotational kinetic energy of the drill bit itself to provide vibration and loosening resistance far exceeding that of traditional spring 330 anti-loosening or thread sealant. It forms a dual guarantee of static pre-locking by spring 330 and dynamic wedging by centrifugal force, without the need for maintenance intervention.

[0033] It should be noted that the guide bushing 100, ball bearing 200 and bolt 310 mentioned above are all devices with relatively mature existing technology. The specific models can be selected according to actual needs, and will not be elaborated here.

[0034] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A retractable roof bolter guide, characterised in that, include: A guide bushing (100) has a chip removal groove (110) on its side end, and ball bearings (200) that are staggered with the chip removal groove (110) are embedded in the side end of the guide bushing (100). A countersunk hole (120) is provided on the top of the guide bushing (100), and a positioning groove (130) communicating with the countersunk hole (120) is provided inside the guide bushing (100). The locking mechanism (300) includes a bolt (310) inserted into the countersunk hole (120). The bolt (310) has a mounting cavity (311) at the side end of its head that communicates with the positioning groove (130). The mounting cavity (311) is slidably connected to a locking block (320) that is inserted into the positioning groove (130). The locking block (320) and the positioning groove (130) are always located on the side of the bolt (310) facing away from the axis of the guide bushing (100).

2. A retractable roof bolter guide as claimed in claim 1 wherein, A spring (330) is fixedly connected to one end of the locking block (320) facing away from the positioning groove (130), and one end of the spring (330) is in contact with the mounting cavity (311).

3. A retractable roof bit guide as claimed in claim 2, wherein, The locking block (320) is located in the positioning groove (130) and its local cross-sectional shape is an isosceles triangle. One end of the locking block (320) located inside the positioning groove (130) has a rounded corner.

4. A retractable roof bit guide as claimed in claim 3, wherein, The horizontal depth of the positioning groove (130) is less than the horizontal length of the locking block (320), and the horizontal depth of the positioning groove (130) is greater than the local horizontal length of the locking block (320) whose local cross-sectional shape is an isosceles triangle.

5. A retractable roof bit guide as claimed in claim 4, wherein, The locking block (320) is cylindrical in shape when located outside the positioning groove (130), and conical in shape when located inside the positioning groove (130).

6. The retractable roof bolter guide of claim 1, wherein, The positioning groove (130) and the countersunk hole (120) are beveled at the connection.

7. A retractable roof bit guide as defined in claim 2, wherein, An anti-detachment block (340) is slidably connected inside the mounting cavity (311), and the two ends of the anti-detachment block (340) are fixedly connected to a locking block (320) and a spring (330) respectively.

8. A retractable roof bit guide as claimed in claim 7, wherein, The vertical cross-sectional shape of the mounting cavity (311) is convex, and the vertical cross-sectional height of the anti-detachment block (340) is greater than the vertical cross-sectional inner diameter of the opening of the mounting cavity (311).

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