Variable diameter uphole hot melt drill bit

Abstract

The application discloses an up-drilling hot melting drill bit with variable diameter, and belongs to the technical field of polar ice cap drilling, which comprises a first drill bit body, a spline rod, a first spring, a sliding sleeve, a second spring, a second drill bit body, a connecting rod, a first fixing block, a third spring, a limiting sleeve, a fourth spring, a second fixing block, an outer tube, a third drill bit body, a supporting rod, a fifth spring and a limiting gasket, which maintains a small diameter when drilling downward and increases the diameter when drilling upward, so that a large-diameter borehole is formed, and the problem that a recyclable hot melting detector is prone to being stuck when drilling upward in a dry hole section is solved; the interaction force between the drill bit and the ice layer is used as the power for increasing the diameter of the drill bit, and the drill bit can be self-locked when the diameter of the drill bit is increased to the maximum; the setting height of the second drill bit body and the third drill bit body is controlled, so that the retraction and extension movements of the second drill bit body and the third drill bit body are performed at different heights, the mutual interference of the second drill bit body and the third drill bit body is avoided, and the second drill bit body and the third drill bit body can be spliced into a complete ring after being extended, and the structure is simple and reliable.

Description

Technical Field

[0001] This invention belongs to the field of polar ice sheet drilling technology, and relates to a thermomelting drill bit, particularly a variable diameter upward drilling thermomelting drill bit. Background Technology

[0002] Retrievable thaw detectors are a crucial technology for pollution-free drilling and sampling of subglacial lakes in polar regions. They consist of two thaw drill bits, one upper and one lower, used to melt the ice during upward and downward drilling respectively. During downward drilling, the lower thaw drill bit is activated for heating, while the detector extends a cable to melt the ice as it drills downwards. The meltwater in the borehole refreezes and seals the borehole, creating a closed melting chamber for the detector. During upward drilling, the upper thaw drill bit is activated, and the detector retracts the cable to melt the ice as it drills upwards, returning to the surface along the cable. However, this technology suffers from drawbacks. Because ice shrinks as it melts into water, a dry section without meltwater exists above the melting chamber. When drilling reaches this dry section, the meltwater from the thaw drill bit flows down the drill string, preventing effective borehole enlargement. The resulting borehole diameter is roughly the same as the drill bit diameter. For detectors several meters long, a small gap between the detector and the borehole can easily lead to stuck drill bits. Increasing the diameter of the top-heat-melting drill bit can solve the problem of stuck drill bit when drilling upwards, but when drilling downwards, a large-diameter top-heat-melting drill bit is more likely to cause stuck drill bit. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of easy jamming of recyclable thermal fusion detectors during upward drilling in dry hole sections. A variable diameter upward drilling thermal fusion drill bit is proposed. When drilling downward, the diameter of the drill bit is the same as that of the detector, and when drilling upward, the diameter can be increased to form a large diameter borehole, thereby solving the problem of easy jamming of recyclable thermal fusion detectors during upward drilling in dry hole sections.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned objective is as follows: a variable diameter upward drilling thermoforming drill bit, comprising a first drill bit body and a heating rod disposed inside the first drill bit body, and further comprising a spline rod, a first spring, a sliding sleeve, a second spring, a second drill bit body, a connecting rod, a first fixing block, a third spring, a limiting sleeve, a fourth spring, a second fixing block, an outer tube, a third drill bit body, a support rod, a fifth spring, and a limiting washer; the first fixing block and the second fixing block are located inside the outer tube and are coaxially arranged; the first fixing block and the second fixing block have spline holes machined at their centers for cooperating with the spline rod; the spline rod is arranged relative to the spline hole in a manner that prevents relative rotation but allows axial upward movement; a T-shaped groove is provided on the upper surface edge of the first fixing block, and the first fixing block... The upper surface of the fixed block is also provided with an annular boss, and the top of the annular boss is provided with a step with an outward bevel. This step with an outward bevel is used to cooperate with the annular groove at the bottom of the first drill bit body, and locks it when the first drill bit body moves to the lower limit position. The spline rod is threaded to the bottom of the first drill bit body and the two are arranged coaxially. Two sliding sleeves and a limiting sleeve are respectively installed on the outside of the spline rod. The sliding sleeves can slide freely relative to the spline rod, and the limiting sleeve is fixed at the fixed position of the spline rod. The two sliding sleeves are the upper sliding sleeve and the lower sliding sleeve. A first spring is installed between the upper sliding sleeve and the first drill bit body, a second spring is installed between the upper sliding sleeve and the lower sliding sleeve, a third spring is installed between the lower sliding sleeve and the first fixed block, and a fourth spring is installed between the limiting sleeve and the second fixed block. The connecting rod The system is divided into two connecting rods: connecting rod one and connecting rod two. Connecting rod one is located between the second drill bit body and the lower sliding sleeve. Connecting rod one, the second drill bit body, and the lower sliding sleeve form a parallelogram linkage mechanism. Connecting rod two is connected between the third drill bit body and the upper sliding sleeve. Connecting rod two, the third drill bit body, and the upper sliding sleeve form a parallelogram linkage mechanism. The second and third drill bit bodies are always in a vertical state. When the upper and lower sliding sleeves reciprocate up and down along the spline rod, connecting rod one and connecting rod two respectively drive the second and third drill bit bodies to reciprocate in the vertical direction. The overall external shape of the first drill bit body is a positive cone, and an inverted conical step is provided at the bottom of the first drill bit body to guide the second and third drill bit bodies. An annular groove with an inner step is machined on the bottom surface of the first drill bit body. The second... The drill bit body and the third drill bit body are arranged alternately. The upper part of the second drill bit body and the third drill bit body are arc-shaped blocks with inner and outer conical surfaces, and the lower part are slender rods with rectangular cross sections. The bottom of the slender rod of the second drill bit body is provided with a T-shaped step for engaging with a T-shaped groove provided on the first fixed block. The bottom of the slender rod of the third drill bit body is provided with a T-shaped step for engaging with a T-shaped groove provided on the support rod. All T-shaped steps can slide freely in their corresponding T-shaped grooves. The arc-shaped blocks of the second drill bit body are provided with inclined surfaces that increase from top to bottom at both ends, and the arc-shaped blocks of the third drill bit body are provided with inclined surfaces that decrease from top to bottom at both ends. When the second drill bit body and the third drill bit body move to the upper limit position, the inclined surfaces of the second drill bit body and the third drill bit body contact each other and splice together to form a complete ring.The support rod is generally round, with its lower part inserted into and slidingly engaged with the first fixing block. The bottom is connected to a limiting washer via screws. The top and middle sections of the support rod are respectively provided with a first step and a second step. A fifth spring is installed between the first step and the first fixing block. The second step is used to limit the lower movement of the support rod, and the limiting washer is used to limit the upper movement of the support rod. A T-groove is machined on the top of the support rod.

[0005] Furthermore, the first drill bit body has a central hole for a cable to pass through, and the top of the central hole is conical.

[0006] Furthermore, the center of the spline bar is provided with a through hole for the cable to pass through.

[0007] Furthermore, one end of the connecting rod one is hinged to the second drill bit body via the first pin, and the other end is hinged to the sliding sleeve via the second pin. Both ends of the connecting rod one can rotate freely around the first pin and the second pin respectively. One end of the connecting rod two is hinged to the third drill bit body via the first pin, and the other end is hinged to the upper sliding sleeve via the second pin. Both ends of the connecting rod two can rotate freely around the first pin and the second pin respectively.

[0008] Furthermore, rectangular grooves running from top to bottom are evenly distributed around the annular boss on the upper surface of the first fixed block to provide space for the movement of the connecting rod.

[0009] Furthermore, there are three of each of the second and third drill bit bodies.

[0010] Furthermore, the first fixing block and the second fixing block are arranged facing each other vertically, and the edges of the first fixing block and the second fixing block are respectively connected to the inner wall of the outer tube by screws.

[0011] Furthermore, the center of the first fixing block is provided with a recessed area for placing the third spring, and through holes for the support rod to pass through are evenly distributed around the recessed area.

[0012] Furthermore, the first spring, the second spring, the third spring, the fourth spring, and the fifth spring are all compression springs.

[0013] Through the above design scheme, the present invention can bring the following beneficial effects:

[0014] 1. The present invention provides a variable diameter upward drilling thermal fusion drill bit, which maintains a small diameter when drilling downward and increases the diameter when drilling upward, thereby forming a large diameter borehole, and solves the problem that retrievable thermal fusion detectors are prone to getting stuck when drilling upward in dry hole sections;

[0015] 2. This invention uses the interaction force between the drill bit and the ice layer as the driving force for increasing the drill bit diameter, and completes self-locking when the drill bit increases to its maximum diameter, resulting in a simple and reliable structure;

[0016] 3. By controlling the height of the second and third drill bits, the present invention allows their retraction and extension movements to occur at different heights, thus avoiding mutual interference. At the same time, after extension, all the second and third drill bits can be spliced ​​into a complete ring, resulting in a simple and reliable structure. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to understand the invention, but do not constitute an improper limitation of the invention. In the drawings:

[0018] Figure 1 This is a cross-sectional view of a variable diameter upward drilling thermomelting drill bit proposed in this invention;

[0019] Figure 2 This is an external schematic diagram of the variable diameter upward drilling fusion drill bit proposed in this invention after its diameter has been increased;

[0020] Figure 3 This is a schematic diagram of the structure of a variable diameter upward drilling fusion drill bit proposed in this invention in its small diameter state;

[0021] Figure 4 This is an external schematic diagram of a variable diameter upward drilling fusion drill bit proposed in this invention in its small diameter state;

[0022] Figure 5 This is a schematic diagram of the structure of the second drill bit body in this invention;

[0023] Figure 6 This is a schematic diagram of the third drill bit body structure in this invention;

[0024] Figure 7 This is a schematic diagram of the first fixing block structure in this invention.

[0025] The markings in the diagram are as follows: 1-First drill bit body; 2-Heating rod; 3-Splined rod; 4-First spring; 5-Sliding sleeve; 6-Second spring; 7-Second drill bit body; 8-First pin; 9-Connecting rod; 10-Second pin; 11-First fixing block; 12-Third spring; 13-Limiting sleeve; 14-Fourth spring; 15-Second fixing block; 16-Outer tube; 17-Cable; 18-Third drill bit body; 19-Support rod; 20-Fifth spring; 21-Limiting washer; 22-Annular boss. Detailed Implementation

[0026] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. To avoid obscuring the essence of the invention, well-known methods, processes, flows, and elements are not described in detail. In the description of the invention, it should be understood that the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only, and the features defined by "first," "second," "third," "fourth," and "fifth" do not indicate any order, quantity, or importance, but are merely used to distinguish different components.

[0027] like Figures 1 to 7 As shown, a variable diameter upward drilling thermoforming drill bit includes a first drill body 1, a heating rod 2, a splined rod 3, a first spring 4, a sliding sleeve 5, a second spring 6, a second drill body 7, a connecting rod 9, a first fixing block 11, a third spring 12, a limiting sleeve 13, a fourth spring 14, a second fixing block 15, an outer tube 16, a cable 17, a third drill body 18, a support rod 19, a fifth spring 20, and a limiting washer 21. The first fixing block 11 and the second fixing block 15 are located inside the outer tube 16 and are coaxially arranged. The first fixing block 11 and the second fixing block 15 are arranged vertically opposite each other. The edges of the first fixing block 11 and the second fixing block 15 are respectively connected to the inner wall of the outer tube 16 by screws. The center of the first fixing block 11 and the second fixing block 15 is machined with a splined rod for connecting with the splined rod. The splined rod 3 can slide up and down along the splined hole, but cannot rotate relative to it. The center of the first fixing block 11 is provided with a recessed area for placing the third spring 12, and the recessed area is surrounded by through holes for the support rod 19 to pass through. The upper surface edge of the first fixing block 11 is provided with three T-shaped grooves, which are used to limit the T-shaped steps at the bottom of the three second drill bits 7. At the same time, the upper surface of the first fixing block 11 is also provided with an annular boss 22. The annular boss 22 is provided with six rectangular grooves that run from top to bottom to provide space for the movement of the connecting rod 9. The top of the annular boss 22 is provided with a step with an outer bevel for cooperating with the annular groove at the bottom of the first drill bit 1, and locking it when the first drill bit 1 moves to the lower limit.

[0028] The spline rod 3 is threaded to the bottom of the first drill bit body 1 and the two are arranged coaxially. The center of the spline rod 3 is provided with a through hole for the cable 17 to pass through. Two sliding sleeves 5 and a limiting sleeve 13 are respectively installed on the outside of the spline rod 3, and the two sliding sleeves 5 and the limiting sleeve 13 are splined with the limiting sleeve 13. The sliding sleeves 5 can slide freely on the spline rod 3, while the limiting sleeve 13 is fixed in a fixed position on the spline rod 3. The two sliding sleeves 5 are the upper sliding sleeve and the lower sliding sleeve, respectively. A first spring 4 is installed between the upper sliding sleeve and the first drill bit body 1, a second spring 6 is installed between the upper sliding sleeve and the lower sliding sleeve, a third spring 12 is installed between the lower sliding sleeve and the first fixing block 11, and a fourth spring 14 is installed between the limiting sleeve 13 and the second fixing block 15. Each of the sliding sleeves 5 is provided with a spline hole in the center for splined engagement with the spline rod 3, and three evenly distributed rectangular slots on the outside for placing the connecting rod 9. The connecting rod 9 is divided into two groups. For ease of description, the first group is called connecting rod one and the second group is called connecting rod two. Connecting rod one is located between the second drill body 7 and the sliding sleeve. Connecting rod one, the second drill body 7 and the sliding sleeve form a parallelogram linkage mechanism. Connecting rod two is connected between the third drill body 18 and the upper sliding sleeve. Connecting rod two, the third drill body 18 and the upper sliding sleeve form a parallelogram linkage mechanism. The second drill body 7 and the third drill body 18 are always in a vertical state. When the upper sliding sleeve and the lower sliding sleeve move up and down along the spline rod 3, connecting rod one and connecting rod two respectively drive the second drill body 7 and the third drill body 18 to move back and forth in the vertical direction.

[0029] The first drill bit body 1 has a central hole for the cable 17 to pass through. The top of the central hole is conical so that meltwater from the ice layer can flow into the central hole of the first drill bit body 1 to cool the cable 17. The first drill bit body 1 has six to eight circular countersunk holes inside for installing the heating rod 2. The overall shape of the first drill bit body 1 is conical. An inverted conical step is provided at the bottom of the first drill bit body 1 to guide the second drill bit body 7 and the third drill bit body 18. An annular groove with an inner step is machined on the bottom surface of the first drill bit body 1 to cooperate with the annular boss 22 of the first fixing block 11 with an outer inclined step on the top.

[0030] There are three of each of the second drill bit body 7 and the third drill bit body 18, arranged alternately. The upper part of each drill bit body 7 and the third drill bit body 18 is an arc-shaped block with inner and outer conical surfaces, and the lower part is a slender rod with a rectangular cross-section. Two circular holes are provided at the bottom of the slender rod for connection to the connecting rod 9 via the first pin 8. The bottom of the slender rod of the second drill bit body 7 has a T-shaped step for engaging with the T-shaped groove of the first fixing block 11. The slender rod of the third drill bit body 18... The bottom of the long rod is provided with a T-shaped step for engaging with the T-shaped groove of the support rod 19. All T-shaped steps can slide freely within their respective T-shaped grooves. The arc-shaped block of the second drill bit body 7 has inclined surfaces that increase from top to bottom at both ends, and the arc-shaped block of the third drill bit body 18 has inclined surfaces that decrease from top to bottom at both ends. When the second drill bit body 7 and the third drill bit body 18 move to their upper limit, the inclined surfaces of the second drill bit body 7 and the third drill bit body 18 come into contact with each other and are joined together to form a complete ring.

[0031] The support rod 19 is generally round. The lower part of the support rod 19 is inserted into the through hole of the first fixing block 11 and slides with the through hole. The bottom of the support rod 19 is connected to the limiting washer 21 by screws. The top and middle parts of the support rod 19 are respectively provided with a first step and a second step. A fifth spring 20 is installed between the first step and the first fixing block 11. The second step is used to limit the lower position of the support rod 19, and the limiting washer 21 is used to limit the upper position of the support rod 19. The top of the support rod 19 is machined with a T-shaped groove to cooperate with the T-shaped step at the bottom of the third drill bit body 18.

[0032] The first spring 4, the second spring 6, the third spring 12, the fourth spring 14, and the fifth spring 20 are all compression springs.

[0033] Each of the second drill bit body 7 and the third drill bit body 18 is connected to two connecting rods 9 with its corresponding sliding sleeve 5, thereby utilizing the motion characteristics of the parallelogram to ensure that the second drill bit body 7 and the third drill bit body 18 are always in a vertical state.

[0034] During downward drilling, under the thrust of the fourth spring 14, the limiting sleeve 13 contacts the bottom surface of the first fixing block 11, thereby limiting the position of the first drill bit body 1 and the spline rod 3; simultaneously, the sliding sleeve connected to the second drill bit body 7 moves upward under the thrust of the third spring 12, and drives the second drill bit body 7 to slide inward along the T-groove of the first fixing block 11 through the connecting rod until the second drill bit body 7 slides to the limit position of the T-groove of the first fixing block 11, thereby limiting the position of the first drill bit body 1 and the spline rod 3. The second drill bit body 7 is at its maximum retracted position; the upper sliding sleeve connected to the third drill bit body 18 moves upward under the thrust of the second spring 6, and drives the third drill bit body 18 to slide inward along the T-groove of the support rod 19 through the second connecting rod until the third drill bit body 18 slides to the limit position of the T-groove of the support rod 19, thereby limiting the maximum retracted position of the third drill bit body 18; the diameter of the second drill bit body 7 and the third drill bit body 18 after retraction is smaller than the maximum diameter of the first drill bit body 1 and the outer tube 16, to prevent the formation of a step that hinders drilling.

[0035] During upward drilling, the first drill bit body 1 and splined rod 3 will move downward under the pressure of the ice layer, and push the upper sliding sleeve connected to the third drill bit body 18 downward through the first spring 4. At this time, since the support rod 19 remains stationary under the thrust of the fifth spring 20, the upper sliding sleeve will push the third drill bit body 18 outward along the T-shaped groove at the top of the support rod 19 through the connecting rod 2. When the connecting rod 2 contacts the top surface of the support rod 19, the third drill bit body 18 extends to its maximum diameter. During this process, the second spring 6 will also push... The sliding sleeve connected to the second drill bit body 7 moves downward, thereby pushing the second drill bit body 7 to slide outward along the T-shaped groove of the first fixing block 11 via the connecting rod 1. After the connecting rod 1 contacts the first fixing block 11, the second drill bit body 7 extends to its maximum diameter. At this point, since the support rod 19 has not moved, the third drill bit body 18, extended to its maximum diameter, is located above the second drill bit body 7, and the two do not interfere with each other. When the first drill bit body 1 continues to move downward, the inner conical surface at the top of the third drill bit body 18 will first contact the inner conical surface at the bottom of the first drill bit body 1. When the first drill bit body 1 continues to move downwards, it drives the third drill bit body 18 and the support rod 19 to move downwards simultaneously, and causes the second drill bit body 7 to enter the gap between two adjacent third drill bit bodies 18 and make contact with the bottom conical surface of the first drill bit body 1, so that the second drill bit body 7 and the third drill bit body 18 form a complete ring; at the same time, the annular boss 22 of the first fixing block 11 will contact the annular groove at the bottom of the first drill bit body 1, and under the guiding action of the step with an outer inclined surface provided on the top of the annular boss 22, it will form a shape When the first drill bit body 1 enters the bottom annular groove, and the bottom conical surface of the first drill bit body 1 contacts both the second drill bit body 7 and the third drill bit body 18, the annular boss 22 of the first fixing block 11 will completely enter the bottom annular groove of the first drill bit body 1. At this time, the annular boss 22 of the first fixing block 11 with an outer inclined step extends into the inner step of the bottom annular groove of the first drill bit body 1 through deformation, thereby locking the position of the first drill bit body 1 and ensuring that even if the entire molten drill bit is separated from the ice layer, the molten drill bit can still maintain its maximum diameter.

[0036] Furthermore, the first drill bit body 1, the second drill bit body 7, and the third drill bit body 18 are all made of metals with high thermal conductivity, such as copper and aluminum alloys, to improve the ice melting rate.

[0037] Working principle of the invention:

[0038] The variable diameter upward drilling thermomelting drill bit provided by this invention, when drilling downwards, because the upper part of the first drill bit body 1 does not contact the ice layer, the first drill bit body 1 and the spline rod 3 will be in the upper limit position under the thrust of the fourth spring 14, and the three support rods 19 will also be in the upper limit position under the thrust of the fifth spring 20; the sliding sleeve connected to the three second drill bit bodies 7 moves upward under the thrust of the third spring 12, and drives the three second drill bit bodies 7 to slide inward along the T-shaped groove of the first fixing block 11 through the connecting rod 2, until the second drill bit body 7 contacts one side of the T-shaped groove of the first fixing block 11, so that the three second drill bit bodies 7 retract to the minimum diameter position; and The upper sliding sleeves of the three connected third drill bit bodies 18 move upward under the thrust of the second spring 6, and through the connecting rod 2, drive the three third drill bit bodies 18 to slide inward along the T-shaped grooves of the three support rods 19 until the third drill bit bodies 18 slide to the limit position of the T-shaped grooves of the support rods 19 and stop, thereby causing the three third drill bit bodies 18 to retract to the minimum diameter position. Since the support rods 19 are at the upper limit position, the height of the third drill bit bodies 18 is higher than that of the second drill bit body 7, so the second drill bit body 7 does not interfere with the retraction of the third drill bit bodies 18. At this position, since the maximum outer diameter of each upper component is smaller than the diameter of the outer tube 16, it will not cause jamming during the downward drilling process.

[0039] When the variable diameter upward drilling thermomelting drill bit provided by this invention drills upward, the first drill bit body 1 will come into contact with the ice layer. At this time, since the heating rod 2 is not powered, the first drill bit body 1 has little effect on melting the ice layer. Therefore, when the detector moves upward as a whole, the first drill bit body 1 will move downward relative to the outer tube 16 under the thrust of the ice layer, and push the upper sliding sleeve connected to the third drill bit body 18 downward through the first spring 4. At this time, since the support rod 19 remains stationary under the thrust of the fifth spring 20, the upper sliding sleeve will push the third drill bit body 18 along the support rod 19 through the connecting rod 2. The T-slot of the second drill bit 18 slides outward. When the second connecting rod contacts the top surface of the support rod 19, the third drill bit body 18 extends to its maximum diameter. During this process, the second spring 6 also pushes the sliding sleeve connected to the second drill bit body 7 downward, thereby pushing the second drill bit body 7 to slide outward along the T-slot of the first fixing block 11 through the first connecting rod 1 until the first connecting rod contacts the first fixing block 11. At this time, the second drill bit body 7 extends to its maximum diameter. Since the support rod 19 has not moved, the third drill bit body 18, which has extended to its maximum diameter, is still located above the second drill bit body 7, and their extension movements do not interfere with each other. As the drill bit body 1 continues to move downward relative to the outer tube 16, the inner conical surface at the top of the third drill bit body 18 will first contact the bottom conical surface of the first drill bit body 1. As the first drill bit body 1 continues to move downward, it will drive the third drill bit body 18 and the support rod 19 downward simultaneously, causing the second drill bit body 7 to enter the gap between the third drill bit bodies 18 and contact the bottom conical surface of the first drill bit body 1, thus forming a complete ring between the second drill bit body 7 and the third drill bit body 18. Simultaneously, the annular boss 22 of the first fixing block 11 will contact the annular groove at the bottom of the first drill bit body 1, thereby creating a band on the top of the annular boss 22. Under the guiding effect of the step with an outer bevel, the drill bit deforms and enters the annular groove at the bottom of the first drill bit body 1. When the conical surface at the bottom of the first drill bit body 1 contacts both the second drill bit body 7 and the third drill bit body 18, the annular boss 22 of the first fixing block 11 will completely enter the annular groove at the bottom of the first drill bit body 1. At this time, the step with an outer bevel provided on the top of the annular boss 22 of the first fixing block 11 extends into the inner step of the annular groove at the bottom of the first drill bit body 1 through deformation, thereby locking the position of the first drill bit body 1 and ensuring that even if the molten drill bit loses contact with the ice layer, the molten drill bit can still maintain its maximum diameter.

[0040] At this time, the heating rod 2 is powered on, and the thermal melting drill bit begins to melt ice and drill. The meltwater in the ice layer above the center hole of the first drill bit body 1 will flow into the center hole of the first drill bit body 1 and cool the cable 17 to prevent the cable 17 from being damaged due to overheating. The meltwater in the ice layer outside the center hole of the first drill bit body 1 will be melted by the conical surface formed by the combination of the first drill bit body 1, the second drill bit body 7 and the third drill bit body 18, so that the diameter of the drill hole is larger than the diameter of the outer tube 16, ensuring that the detector can pass through safely and smoothly.

Claims

1. A variable diameter upward drilling thermoforming drill bit, comprising a first drill bit body (1) and a heating rod (2) disposed inside the first drill bit body (1), characterized in that, It also includes a spline rod (3), a first spring (4), a sliding sleeve (5), a second spring (6), a second drill bit body (7), a connecting rod (9), a first fixing block (11), a third spring (12), a limiting sleeve (13), a fourth spring (14), a second fixing block (15), an outer tube (16), a third drill bit body (18), a support rod (19), a fifth spring (20), and a limiting washer (21); the first fixing block (11) and the second fixing block (15) are located inside the outer tube (16) and are coaxially arranged. The first fixing block (11) and the second fixing block (15) have spline holes machined in their centers for cooperating with the spline rod (3). The spline rod (3) is relative to The spline holes are arranged in a manner that prevents relative rotation but allows axial movement; the upper surface edge of the first fixing block (11) is provided with a T-groove, and the upper surface of the first fixing block (11) is also provided with an annular boss (22), the top of the annular boss (22) is provided with a step with an outer inclined surface, the step with an outer inclined surface is used to cooperate with the annular groove at the bottom of the first drill bit body (1), and lock it when the first drill bit body (1) moves to the lower limit; the spline rod (3) is threaded to the bottom of the first drill bit body (1) and the two are arranged coaxially, and two sliding sleeves (5) and a limiting sleeve (13) are respectively installed on the outside of the spline rod (3), the sliding sleeves (5) can be relative to the spline rod (3) Free sliding, the limiting sleeve (13) is fixed at the fixed position of the spline rod (3), the two sliding sleeves (5) are the upper sliding sleeve and the lower sliding sleeve respectively, a first spring (4) is installed between the upper sliding sleeve and the first drill bit body (1), a second spring (6) is installed between the upper sliding sleeve and the lower sliding sleeve, a third spring (12) is installed between the lower sliding sleeve and the first fixed block (11), and a fourth spring (14) is installed between the limiting sleeve (13) and the second fixed block (15); the connecting rod (9) is divided into connecting rod one and connecting rod two. Connecting rod one is set between the second drill bit body (7) and the lower sliding sleeve. Connecting rod one, the second drill bit body (7) and the lower sliding sleeve form a parallelogram linkage mechanism. Connecting rod two is connected to the first fixed block (11). Between the three drill bit bodies (18) and the upper sliding sleeve, the second connecting rod, the third drill bit body (18) and the upper sliding sleeve form a parallelogram linkage mechanism. The second drill bit body (7) and the third drill bit body (18) are always in a vertical state. When the upper sliding sleeve and the lower sliding sleeve move up and down along the spline rod (3), the first connecting rod and the second connecting rod respectively drive the second drill bit body (7) and the third drill bit body (18) to move back and forth in the vertical direction. The overall shape of the first drill bit body (1) is a positive cone, and an inverted cone-shaped step is provided at the bottom of the first drill bit body (1) to guide the second drill bit body (7) and the third drill bit body (18). An annular groove with an inner step is machined on the bottom surface of the first drill bit body (1).The second drill bit body (7) and the third drill bit body (18) are arranged alternately. The upper part of the second drill bit body (7) and the third drill bit body (18) is an arc-shaped block with inner and outer conical surfaces, and the lower part is a slender rod with a rectangular cross-section. The bottom of the slender rod of the second drill bit body (7) is provided with a T-shaped step for engaging with the T-shaped groove on the first fixing block (11). The bottom of the slender rod of the third drill bit body (18) is provided with a T-shaped step for engaging with the T-shaped groove on the support rod (19), and all T-shaped steps can slide freely in their corresponding T-shaped grooves. The arc-shaped blocks of the second drill bit body (7) are provided with inclined surfaces that increase from top to bottom at both ends, and the arc-shaped blocks of the third drill bit body (18) are provided with inclined surfaces that decrease from top to bottom at both ends. When the second drill bit body (7) When the third drill bit body (18) moves to the upper limit, the inclined surfaces of the second drill bit body (7) and the third drill bit body (18) come into contact with each other and are spliced ​​into a complete ring; the support rod (19) is a round rod in shape. The lower part of the support rod (19) is inserted into the first fixing block (11) and slides with it. The bottom of the support rod (19) is connected to the limiting washer (21) by screws. The top and middle parts of the support rod (19) are respectively provided with a first step and a second step. A fifth spring (20) is installed between the first step and the first fixing block (11). The second step is used to limit the lower position of the support rod (19), and the limiting washer (21) is used to limit the upper position of the support rod (19); a T-shaped groove is machined on the top of the support rod (19).

2. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The first drill bit body (1) has a central hole for the cable (17) to pass through, and the top of the central hole is conical.

3. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The center of the spline rod (3) is provided with a through hole for the cable (17) to pass through.

4. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: One end of the first connecting rod is hinged to the second drill bit body (7) via the first pin (8), and the other end is hinged to the upper sliding sleeve via the second pin (10). The two ends of the first connecting rod can rotate freely around the first pin (8) and the second pin (10), respectively. One end of the second connecting rod is hinged to the third drill bit body (18) via the first pin (8), and the other end is hinged to the upper sliding sleeve via the second pin (10). The two ends of the second connecting rod can rotate freely around the first pin (8) and the second pin (10), respectively.

5. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The annular boss (22) provided on the upper surface of the first fixed block has rectangular grooves that run from top to bottom, providing space for the movement of the connecting rod (9).

6. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The number of the second drill bit body (7) and the third drill bit body (18) are both three.

7. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The first fixing block (11) and the second fixing block (15) are arranged facing each other vertically, and the edges of the first fixing block (11) and the second fixing block (15) are respectively connected to the inner wall of the outer tube (16) by screws.

8. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The first fixing block (11) has a recessed area in the center for placing the third spring (12), and through holes for the support rod (19) to pass through are evenly distributed around the recessed area.

9. The variable diameter upward drilling thermoforming drill bit according to claim 1, characterized in that: The first spring (4), the second spring (6), the third spring (12), the fourth spring (14) and the fifth spring (20) are all compression springs.

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