Eccentric Drill Bit Adjustment Method for Combined Down-the-Hole Hammers

Abstract

This invention discloses a method for adjusting an eccentric drill bit in a combined down-the-hole hammer. It is applicable to combined down-the-hole hammers with adjustable eccentric drill bit sizes. The eccentric drill bit is connected to the down-the-hole hammer body via a size adjustment mechanism and a locking mechanism. During adjustment, the eccentric drill bit is first released to a free state using the locking mechanism. Then, the eccentric drill bit is adjusted to a predetermined size using the size adjustment mechanism. Finally, the eccentric drill bit is locked in position again using the locking mechanism. This eccentric drill bit adjustment method simplifies the adjustment operation, improves the adjustment accuracy, effectively reduces the workload of workers, and facilitates smooth drilling operations.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology, and in particular to a method for adjusting an eccentric drill bit for a combined down-the-hole hammer. Background Technology

[0002] Down-the-hole (DH) hammers are indispensable tools in drilling operations. A DH hammer consists of a center drill bit and an eccentric drill bit. The center drill bit is used to advance and drill the hole, while the eccentric drill bit is used to enlarge the hole after the center drill bit has made its hole. Early DH hammers used an integrated structure for the center and eccentric drill bits. During drilling, the two bits interfered with each other, easily causing excessive deviations in the hole's inclination, failing to meet process requirements. Chinese patent CN201310138334.0 discloses a DH hammer with a separate center and eccentric drill bit structure. These two bits work relatively independently, ensuring that the hole's inclination deviation remains within the allowable range. However, some shortcomings still exist. For example, adjusting the diameter of the eccentric drill bit requires workers to install and fix each eccentric enlargement piece using connectors. This process is cumbersome, labor-intensive, and time-consuming, affecting the overall work progress. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for adjusting an eccentric drill bit in a combined down-the-hole hammer, specifically employing the following technical solution:

[0004] The eccentric drill bit adjustment method for combined down-the-hole hammers described in this invention is applicable to combined down-the-hole hammers with adjustable eccentric drill bit sizes, wherein...

[0005] The adjustable eccentric drill bit size combined down-the-hole hammer includes a down-the-hole hammer body and a central drill bit coaxially arranged therewith. Eccentric drill bits are arranged in a ring array around the rotating shaft of the central drill bit. The characteristic is that the eccentric drill bits are connected to the down-the-hole hammer body through a size adjustment mechanism and a locking mechanism.

[0006] The eccentric drill bit adjustment method includes: first, using the locking mechanism to put the eccentric drill bit in a free state; then, using the size adjustment mechanism to adjust the eccentric drill bit to a predetermined size; and finally, using the locking mechanism again to lock the position of the eccentric drill bit.

[0007] The size adjustment mechanism includes a vertical gear shaft disposed at the tail of the eccentric drill bit, and an arc-shaped adjusting rack disposed in the body of the down-the-hole hammer and meshing with the vertical gear shaft, wherein the center of the arc-shaped adjusting rack coincides with the rotation axis of the central drill bit.

[0008] The arc-shaped adjusting racks are interconnected to form a toothed ring, and the meshing teeth of the toothed ring are arranged on the inner surface.

[0009] The down-the-hole hammer body has a first annular groove for setting an arc-shaped adjusting rack and a second annular groove for setting an eccentric drill bit. Between the first annular groove and the second annular groove are several vertical holes for passing through a vertical gear shaft.

[0010] The locking mechanism includes a vertical locking rod with a tension spring on it. A insertion hole perpendicular to the tension spring is provided in the middle of the vertical locking rod. The insertion hole is adapted to a drive component for stretching the tension spring and inserting the two ends of the vertical locking rod into the eccentric drill bit and the down-the-hole hammer body, respectively.

[0011] The eccentric drill bit is provided with a number of positioning holes that are adapted to the vertical chuck, and the positioning holes are distributed in an arc shape with the vertical gear shaft as the center.

[0012] The down-the-hole hammer body is provided with a vertical groove adapted to the vertical locking rod, and the vertical groove is connected to the second annular groove; the down-the-hole hammer body is also provided with a transverse groove adapted to the driving component, and the transverse groove is connected to the vertical groove.

[0013] The tension spring is located at the end of the vertical clamp rod, and its two ends are connected to the vertical clamp rod and the vertical groove, respectively.

[0014] The drive component includes a screw and a transverse sleeve connected to it by a screw. The head of the screw is connected to the body of the down-the-hole hammer through a bearing, and the tail of the screw extends out of the transverse groove.

[0015] The head of the transverse sleeve is a spherical structure, and the body of the transverse sleeve is prismatic; the insertion hole is adapted to the shape of the body of the transverse sleeve, and the entrance end of the insertion hole is provided with a concave spherical surface with a diameter larger than that of the head of the transverse sleeve.

[0016] The eccentric drill bit adjustment method for combined down-the-hole hammers provided by this invention is applicable to combined down-the-hole hammers with adjustable eccentric drill bit sizes. Because the eccentric drill bit is equipped with a vertical gear shaft that meshes with a concentrically arranged arc-shaped adjusting rack, the size of the eccentric drill bit extending beyond the hammer body can be adjusted synchronously to adapt to different drilling requirements. Simultaneously, by adjusting the connection between the horizontal drive component and the vertical locking rod, the position locking and unlocking of the eccentric drill bit is easily achieved, facilitating the switching between drilling and adjustment operations. The eccentric drill bit adjustment method adopted in this invention simplifies the adjustment operation of the eccentric drill bit, improves the adjustment accuracy, effectively reduces the workload of workers, and facilitates the smooth progress of drilling operations. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the down-the-hole hammer in this invention.

[0018] Figure 2 yes Figure 1 Cross-sectional view.

[0019] Figure 3 yes Figure 1 A schematic diagram of the eccentric drill bit section.

[0020] Figure 4 yes Figure 3 An exploded view of a single eccentric drill bit. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0022] like Figure 1-4 As shown, the eccentric drill bit adjustment method for combined down-the-hole hammers of the present invention is applicable to combined down-the-hole hammers with adjustable eccentric drill bit sizes. It includes a down-the-hole hammer body 1 and a central drill bit 2 coaxially arranged therewith. Eccentric drill bits 3 are arranged in a ring array around the rotating shaft of the central drill bit 2. The eccentric drill bits 3 are connected to the down-the-hole hammer body 1 through a size adjustment mechanism and a locking mechanism.

[0023] Specifically, the size adjustment mechanism includes a vertical gear shaft 41 installed at the tail of the eccentric drill bit 3, and an arc-shaped adjusting rack 42 installed inside the down-the-hole hammer body 1 and meshing with the vertical gear shaft 41. The center of each arc-shaped adjusting rack 42 coincides with the rotation axis of the central drill bit 2. The arc-shaped adjusting rack 42 is installed in a first annular groove on the down-the-hole hammer body 1, the eccentric drill bit 3 is installed in a second annular groove located above the first annular groove, and the vertical gear shaft 41 is installed in a vertical hole connecting the first and second annular grooves. For ease of installation and operation, the arc-shaped adjusting racks 42 are interconnected to form a gear ring. The meshing teeth of the gear ring can be set on the inner surface (see...). Figure 3 It can also be set on the outer surface. When the gear ring rotates, the vertical gear shaft 41 drives each eccentric drill bit 3 to rotate synchronously until it reaches the size required to extend beyond the body 1 of the down-the-hole hammer, and then stops.

[0024] The locking mechanism includes a vertical locking rod 51, which is located in a vertical groove on the down-the-hole hammer body 1. All vertical grooves are located above and connected to the second annular groove. A tension spring 52 is installed at the top of each vertical locking rod 51, and the two ends of the tension spring 52 are fixedly connected to the vertical locking rod 51 and the vertical groove, respectively. A insertion hole 53 perpendicular to the tension spring 52 is provided in the middle of the vertical locking rod 51. This insertion hole 53 is adapted to a drive component for stretching the tension spring 52 and inserting the bottom of the vertical locking rod 51 into the eccentric drill bit 3. Since the eccentric drill bit 3 has multiple extension positions, several positioning holes 54 adapted to the vertical locking rods 51 are provided on the eccentric drill bit 3, and the positioning holes 54 in the same group are distributed in an arc shape with the vertical gear shaft 41 on the eccentric drill bit 3 as the center. The aforementioned driving component includes a screw 55 and a transverse sleeve 56 screwed to it. The screw 55 passes through a transverse groove that communicates with the vertical groove. Its head is connected to the down-the-hole hammer body 1 via a bearing 57, and its tail extends out of the transverse groove for easy screwing. Furthermore, the head of the transverse sleeve 56 has a spherical structure, and the body of the transverse sleeve 56 is prismatic. Correspondingly, the insertion hole 53 is adapted to the shape of the body of the transverse sleeve 56, and the inlet end of the insertion hole 53 is provided with a concave spherical surface with a diameter larger than that of the head of the transverse sleeve 56.

[0025] The eccentric drill bit adjustment method of the present invention includes: first, using a locking mechanism to put the eccentric drill bit 3 in a free state; then, using a size adjustment mechanism to adjust the eccentric drill bit 3 to a predetermined size; and finally, using the locking mechanism again to lock the position of the eccentric drill bit 3.

[0026] The following details the process of locking and unlocking the position of the eccentric drill bit 3.

[0027] When the screw 55 is rotated clockwise, the transverse sleeve 56 fitted on its outer side will move along the screw 55 toward the insertion hole 53 of the vertical locking rod 51. The transverse sleeve 56 first contacts the concave spherical surface with a larger flare. When it enters the rear main body section, since the insertion hole 53 is adapted to the body shape of the transverse sleeve 56, the tension spring 52 at the top of the vertical locking rod 51 is stretched by a downward force under the action of the transverse sleeve 56, thereby causing the vertical locking rod 51 to move downward as a whole and be inserted into the corresponding positioning hole 54, thus completing the position locking of the eccentric drill bit 3 (drilling can then be carried out).

[0028] When the screw 55 is rotated counterclockwise, the transverse sleeve 56 fitted on its outer side will gradually disengage from the insertion hole 53 along the screw 55; when the transverse sleeve 56 reaches the concave spherical surface of the insertion hole 53, the tension spring 52 will return to its contracted state under the action of elastic restoring force, driving the vertical locking rod 51 to disengage from the positioning hole 54. At this time, the eccentric drill bit 3 can rotate freely under the action of the size adjustment mechanism to adjust its position.

[0029] It should be noted that in the description of this invention, terms such as "front," "rear," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

Claims

1. A method for adjusting an eccentric drill bit in a combined down-the-hole hammer, applicable to combined down-the-hole hammers with adjustable eccentric drill bit size, characterized in that: The adjustable eccentric drill bit size combined down-the-hole hammer includes a down-the-hole hammer body and a central drill bit coaxially arranged therewith. Eccentric drill bits are arranged in a ring array around the rotating shaft of the central drill bit. The eccentric drill bits are connected to the down-the-hole hammer body through a size adjustment mechanism and a locking mechanism. The size adjustment mechanism includes a vertical gear shaft disposed at the tail of the eccentric drill bit, and an arc-shaped adjustment rack disposed in the body of the down-the-hole hammer and meshing with the vertical gear shaft, wherein the center of the arc-shaped adjustment rack coincides with the rotation axis of the central drill bit. The down-the-hole hammer body is provided with a first annular groove for setting an arc-shaped adjusting rack and a second annular groove for setting an eccentric drill bit. A plurality of vertical holes for passing through a vertical gear shaft are provided between the first annular groove and the second annular groove. The locking mechanism includes a vertical locking rod, on which a tension spring is provided. A insertion hole perpendicular to the tension spring is opened in the middle of the vertical locking rod. The insertion hole is adapted to a driving component for stretching the tension spring and inserting the two ends of the vertical locking rod into the eccentric drill bit and the down-the-hole hammer body, respectively. The driving component includes a screw and a transverse sleeve connected to it. The head of the screw is connected to the body of the down-the-hole hammer through a bearing, and the tail of the screw extends out of the transverse groove. The head of the transverse sleeve is a spherical structure, and the body of the transverse sleeve is prismatic; the insertion hole is adapted to the shape of the body of the transverse sleeve, and the entrance end of the insertion hole is provided with a concave spherical surface with a diameter larger than that of the head of the transverse sleeve. The eccentric drill bit adjustment method includes: first, using the locking mechanism to put the eccentric drill bit in a free state; then, using the size adjustment mechanism to adjust the eccentric drill bit to a predetermined size; and finally, using the locking mechanism again to lock the position of the eccentric drill bit.

2. The method for adjusting the eccentric drill bit for a combined down-the-hole hammer according to claim 1, characterized in that: The arc-shaped adjusting racks are interconnected to form a toothed ring, and the meshing teeth of the toothed ring are arranged on the inner surface.

3. The method for adjusting the eccentric drill bit for a combined down-the-hole hammer according to claim 1, characterized in that: The eccentric drill bit is provided with a number of positioning holes that are adapted to the vertical chuck, and the positioning holes are distributed in an arc shape with the vertical gear shaft as the center.

4. The method for adjusting the eccentric drill bit for a combined down-the-hole hammer according to claim 1, characterized in that: The down-the-hole hammer body is provided with a vertical groove adapted to the vertical locking rod, and the vertical groove is connected to the second annular groove; the down-the-hole hammer body is also provided with a transverse groove adapted to the driving component, and the transverse groove is connected to the vertical groove.

5. The method for adjusting the eccentric drill bit for a combined down-the-hole hammer according to claim 4, characterized in that: The tension spring is located at the end of the vertical clamp rod, and its two ends are connected to the vertical clamp rod and the vertical groove, respectively.

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