A three-piece jaw fixture

Abstract

The present invention discloses a three-piece jaw clamp, which relates to the technical field of jaw processing. The key points of its technical solution include a clamp body, the clamp body includes a cylinder body, a positioning frame is arranged on the inner side wall of the cylinder body, and three circumferentially evenly distributed positioning grooves are formed between the positioning frame and the cylinder body; the positioning groove includes two positioning surfaces with an included angle of 120°, and the eccentric distance between the intersection line of the two positioning surfaces and the center line of the cylinder body is not less than 8 mm and not more than 12 mm. The present invention can clamp three jaws at the same time, thereby improving the processing efficiency, and can ensure the rigidity of the clamp and reduce the processing difficulty.

Description

Technical Field

[0001] The present invention relates to the technical field of bit leg processing, and more specifically, it relates to a three-piece bit leg fixture. Background Art

[0002] There are two types of cone bits: three-cone bits and single-cone bits, among which the bit leg is the main load-bearing structure. The three-cone bit is assembled and welded together by the 120° surfaces of three bit legs, and each bit leg is equipped with a cone responsible for rock breaking. During the drilling process, in order to facilitate slag discharge, a certain gap and angle must be maintained between the back of the bit leg and the wellbore wall. Therefore, the back of the bit leg must meet the design dimensions. Whether it is the bit leg for a three-cone bit or a single-cone bit, the dynamic balance problem of the lathe spindle must be solved when turning the outer circle of the back of the bit leg. For the bit legs used in three-cone bits, the industry generally adopts a method of installing two bit legs in pairs and point-symmetrically to process them simultaneously, which solves the dynamic balance problem of the lathe while ensuring the processing efficiency.

[0003] To ensure the rigidity of the fixture, the two 120° V-grooves on the fixture that cooperate with the 120° surface of the bit leg cannot communicate. Therefore, the distance between the two V-grooves is generally designed to be 3 mm, that is, the intersection line of the 120° surface of the bit leg deviates from the lathe spindle by 1.5 mm. To further improve the processing efficiency, it is possible to consider processing three bit legs simultaneously. However, if the fixture for processing three pieces at one time is designed according to the method for two pieces, and the intersection line of the V-grooves also deviates from the center of the lathe spindle by 1.5 mm, then the thickness of the three partitions between the V-grooves is only 2.6 mm, which brings great difficulties to the processing and heat treatment of the fixture, and is prone to being bruised during use, with poor fixture rigidity and cannot be used. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a three-piece bit leg fixture, which can clamp three bit legs simultaneously, thereby improving the processing efficiency, and can ensure the rigidity of the fixture and reduce the processing difficulty.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A three-piece bit leg fixture, including a fixture main body, the fixture main body includes a cylinder body, and a positioning bracket is provided on the inner side wall of the cylinder body. Three circumferentially evenly distributed positioning grooves are formed between the positioning bracket and the cylinder body;

[0007] The positioning groove includes two positioning surfaces with an included angle of 120°, and the eccentric distance between the intersection line of the two positioning surfaces and the center line of the cylinder body is not less than 8 mm and not more than 12 mm.

[0008] Further, the eccentric distance between the intersection line of the two positioning surfaces and the center line of the cylinder body is 10 mm.

[0009] Further, define the central plane of the two positioning surfaces as the positioning central plane. The intersection of the three positioning central planes forms an inscribed cylinder, and the center line of the inscribed cylinder coincides with the center line of the cylinder body.

[0010] Further, the positioning frame and the cylinder body are integrally formed.

[0011] Further, a pressing assembly is provided on the cylinder body. The pressing assembly includes a pressing nut and a pressing screw that cooperates with the pressing nut. The end of the pressing screw extends into the positioning groove; the pressing nut is embedded in the side wall of the cylinder body, and a limiting structure for restricting the rotation of the pressing nut is provided between the pressing nut and the cylinder body.

[0012] Further, the center line of the pressing screw is perpendicular to and intersects the intersection line of the two positioning surfaces.

[0013] Further, the pressing nut includes a T-shaped nut, and the limiting structure includes a limiting groove provided on the side wall of the cylinder body and cooperating with the T-shaped nut.

[0014] Further, the limiting groove is provided on the inner side wall of the cylinder body.

[0015] Further, a wear-resistant pressing head is provided at the end of the pressing screw.

[0016] Further, the jaw clamp further includes a flange concentrically installed at the bottom end of the cylinder body, and the cylinder body and the flange are connected by cooperation of screws and key blocks.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. Increase the eccentricity distance between the intersection line of the two positioning surfaces and the center line of the cylinder body to 10 mm, which can increase the thickness of the partition between adjacent positioning grooves to 16 mm, improve the rigidity of the fixture, and thus enable simultaneous machining of three jaws, improving production efficiency;

[0019] 2. When the central plane of the positioning groove passes through the center line of the cylinder body, rotate the positioning groove around the intersection line of the two positioning surfaces, and the three positioning grooves rotate in the same direction, then the distance between the central plane of the jaw back and the center line of the cylinder body can be reduced, and an inscribed cylinder can be formed at the intersection of the three positioning central planes;

[0020] 3. Use a separate pressing nut to provide the threaded hole. When the threaded hole has problems, directly replace the pressing nut without replacing the cylinder body, which can reduce production costs and is convenient for replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1Schematic diagram of the overall structure of a three-piece bit shank clamp in the embodiment;

[0022] Figure 2 Schematic diagram of the structure of the clamp body in the embodiment;

[0023] Figure 3 Schematic diagram of the structure of the clamp and the bit shank in the clamped state in the embodiment.

[0024] In the figure: 1. Cylinder body; 11. Limit groove; 2. Positioning frame; 3. Positioning groove; 4. Flange; 51. Compression screw; 52. Compression nut; 53. Wear-resistant pressure head; 6. Bit shank; 61. Back of the bit shank. Specific implementation mode

[0025] The present invention will be further described in detail below with reference to the accompanying drawings.

[0026] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0027] Embodiment:

[0028] A three-piece bit shank clamp, referring to Figure 1 , which includes a clamp body. The clamp body includes a cylinder body 1. A positioning frame 2 is arranged on the inner side wall of the cylinder body 1. Three circumferentially evenly distributed positioning grooves 3 are formed between the positioning frame 2 and the cylinder body 1; preferably, in this embodiment, the positioning frame 2 and the cylinder body 1 are integrally formed, so as to improve the structural strength and rigidity of the clamp body; the positioning groove 3 includes two positioning surfaces with an included angle of 120°. The eccentricity between the intersection line of the two positioning surfaces and the center line of the cylinder body 1 is not less than 8 mm and not more than 12 mm; preferably, in this embodiment, the eccentricity between the intersection line of the two positioning surfaces and the center line of the cylinder body 1 is 10 mm; after the bit shank 6 is installed in the positioning groove 3, the distance between the intersection line of the 120° surface of the bit shank 6 and the center line of the cylinder body 1 is 10 mm. At this time, the outer circle radius of the back of the bit shank 61 processed will become larger, but the arc of the outer circle of the back of the bit shank 61 is shorter, so the difference between the two extreme positions on both sides of the back of the bit shank 61 and the processed deviation of 1.5 mm is very small, so the bit shank processed with a deviation of 10 mm in this embodiment can be used normally; in this embodiment, the eccentricity between the intersection line of the two positioning surfaces and the center line of the cylinder body 1 is increased to 10 mm, so that the thickness of the partition between adjacent positioning grooves 3 can be increased to 16 mm, and the rigidity of the clamp is improved, so that three bit shanks can be processed simultaneously, improving production efficiency.

[0029] Referring to Figures 1 to 3, the central plane of the two positioning surfaces is defined as the positioning middle plane. In this embodiment, an inscribed cylinder is formed at the intersection of the three positioning middle planes, and the center line of the inscribed cylinder coincides with the center line of the cylinder body 1, so that the distance between the central plane of the back of the jaw and the center line of the cylinder body can be reduced; when the central plane of the positioning groove 3 passes through the center line of the cylinder body 1, the positioning groove 3 is rotated around the intersection line of the two positioning surfaces, and the three positioning grooves 3 rotate in the same direction, so that the distance between the central plane of the back of the jaw and the center line of the cylinder body can be reduced, and an inscribed cylinder can be formed at the intersection of the three positioning middle planes.

[0030] Referring to Figure 1 , in this embodiment, a pressing assembly is arranged on the cylinder body 1. The pressing assembly includes a pressing nut 52 and a pressing screw 51 that cooperates with the pressing nut 52. The end of the pressing screw 51 extends into the positioning groove 3 for pressing the jaw; preferably, the center line of the pressing screw 51 is perpendicular to and intersects the intersection line of the two positioning surfaces and is located on the positioning middle plane; the pressing nut 52 is embedded in the side wall of the cylinder body 1, and a limiting structure for restricting the rotation of the pressing nut 52 is arranged between the pressing nut 52 and the cylinder body 1; in this embodiment, a separate pressing nut 52 is used to provide the threaded hole, so when the threaded hole has problems, the pressing nut 52 can be directly replaced without replacing the cylinder body 1, which can reduce the production cost and is convenient for replacement.

[0031] Referring to Figure 1 , specifically, in this embodiment, the pressing nut 52 is a T-shaped nut, and the limiting structure includes a limiting groove 11 arranged on the side wall of the cylinder body 1 and cooperating with the T-shaped nut; the T-shaped nut is a conventional fastener and can be directly purchased, which is convenient for replacement and has a low replacement cost; the radial protruding part of the T-shaped nut is embedded in the limiting groove 11, so that when the pressing screw 51 rotates, the T-shaped nut cannot rotate, and the pressing action can be smoothly realized; preferably, in this embodiment, the limiting groove 11 is arranged on the inner side wall of the cylinder body 1, so that the radial protruding part of the T-shaped nut is also located inside the cylinder body 1, so that the pressing assembly will not be separated from the cylinder body 1, which is convenient for storage and use; in this embodiment, a through hole with a clearance fit or an interference fit with the T-shaped nut is opened on the side wall of the cylinder body 1. Preferably, the T-shaped nut and the through hole are in an interference fit, which is convenient for replacing the T-shaped nut; of course, in other alternative embodiments, the pressing nut can also be a nut with other structures, which is not limited here, such as an external hexagonal nut, etc., and the external hexagonal nut can be embedded in the side wall of the cylinder body 1; preferably, a wear-resistant pressing head 53 is arranged at the end of the pressing screw 51 in this embodiment, so that the service life of the pressing screw 51 can be extended and the production cost can be reduced; three pressing assemblies are arranged on the cylinder body 1 in this embodiment, that is, each pressing assembly corresponds to a positioning groove 3; in other alternative embodiments, multiple pressing assemblies arranged along the axial direction of the cylinder body 1 can also be configured for one positioning groove 3, which is not limited here.

[0032] Reference Figure 1 Specifically, in this embodiment, the tool joint fixture further includes a flange 4 concentrically installed at the bottom end of the cylinder body 1. The cylinder body 1 and the flange 4 are connected by screws in cooperation with key blocks; the cylinder body 1 and the flange 4 are positioned by key blocks and then fixedly connected by screws, so as to ensure the machining accuracy; during machining, the flange 4 is connected to the main shaft of the lathe, so that the center line of the cylinder body 1 coincides with the center line of the main shaft of the lathe.

Claims

1. A three-piece jaw fixture, characterized in that: It includes a fixture body, and the fixture body includes a cylinder body. A positioning frame is arranged on the inner side wall of the cylinder body, and three circumferentially evenly distributed positioning grooves are formed between the positioning frame and the cylinder body; The positioning groove includes two positioning surfaces with an included angle of 120°. The eccentric distance between the intersection line of the two positioning surfaces and the central axis of the cylinder body is not less than 8 mm and not more than 12 mm; Define the central plane of the two positioning surfaces as the positioning middle plane. An inscribed cylinder is formed at the intersection of the three positioning middle planes, and the central axis of the inscribed cylinder coincides with the central axis of the cylinder body; The positioning frame and the cylinder body are integrally formed.

2. The three-piece jaw fixture according to claim 1, characterized in that: The eccentric distance between the intersection line of the two positioning surfaces and the central axis of the cylinder body is 10 mm.

3. The three-piece jaw fixture according to claim 1 or 2, characterized in that: A pressing assembly is arranged on the cylinder body. The pressing assembly includes a pressing nut and a pressing screw rod that cooperates with the pressing nut. The end of the pressing screw rod extends into the positioning groove; the pressing nut is embedded in the side wall of the cylinder body, and a limiting structure for restricting the rotation of the pressing nut is arranged between the pressing nut and the cylinder body.

4. The three-piece jaw fixture according to claim 3, wherein: The central axis of the pressing screw rod is vertically intersected with the intersection line of the two positioning surfaces.

5. The three-piece jaw fixture according to claim 3, characterized in that: The pressing nut includes a T-shaped nut, and the limiting structure includes a limiting groove arranged on the side wall of the cylinder body and cooperating with the T-shaped nut.

6. The three-piece jaw fixture according to claim 5, wherein: The limiting groove is arranged on the inner side wall of the cylinder body.

7. The three-piece jaw fixture according to claim 3, characterized in that: A wear-resistant pressing head is arranged at the end of the pressing screw rod.

8. The three-piece jaw fixture according to claim 1, characterized in that: The jaw fixture further includes a flange concentrically installed at the bottom end of the cylinder body. The cylinder body and the flange are connected by the cooperation of screws and key blocks.

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