Method for extracting a CDC-16 broken taper shank rammer pick

Abstract

The application discloses a kind of CDC-16 broken taper handle tamping pickaxe extraction methods, by estimating the dismounting force Q' required for broken taper handle tamping pickaxe, the structural characteristics of tamping are combined and according to the principle of inclined plane force enhancement design inclined iron as dismounting tool, and the process of pre-disassembly is analyzed, the optimal structure of inclined iron is determined, finally through external power source to inclined iron exert transverse thrust, so as to take out broken taper handle tamping pickaxe.The application can exert a small force on inclined iron, which can generate a thrust force greater than the dismounting force on the taper handle remaining in the taper hole of the pickaxe arm, thereby completing the dismounting, avoiding replacing the pickaxe arm, reducing the user's use cost, filling the gap in the dismounting technology of CDC-16 broken taper handle tamping pickaxe for large railway maintenance machinery, improving the user's work efficiency and greatly reducing the labor intensity.

Description

Technical Field

[0001] This invention relates to the field of tamping operation technology, and in particular to a method for removing a CDC-16 tamping pick with a broken cone handle. Background Technology

[0002] The CDC-16 tamping machine is mainly used for tamping ballast in turnout areas of ballasted railways. It uses a tamping pick mounted on a tamping device, which is inserted into the ballast to vibrate and clamp it, thus completing the tamping process. The tamping pick is connected by a self-locking tapered shank inserted into a corresponding tapered hole in the pick arm, and locked in place by the taper. As tamping continues, the significant reaction force from the downward insertion of the tamping device tightens the tapered shank lock, increasing the interference fit force of the tapered engagement. During tamping operations, the tamping pick frequently breaks along the large end of the tapered shank, significantly impacting normal railway construction. When this happens, the tapered shank remaining in the tapered hole of the pick arm cannot be removed due to the lack of a point of leverage, requiring replacement of the pick arm to restore equipment functionality, thus significantly increasing user production costs.

[0003] Studying the structure reveals that, to prevent the tamping pick from rotating during operation, a slotted through-hole is machined into the pick arm, and a corresponding flat bar is machined into the top of the pick. During installation, the flat bar is inserted into the slotted through-hole to prevent rotation. A certain gap is left between the top of the flat bar and the slotted through-hole, but this space cannot directly accommodate equipment that can generate pressure greater than the disassembly force. This has become a major pain point for railway large-scale track maintenance machinery construction companies. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for removing a broken cone handle from a CDC-16 tamping pick. Based on the structural characteristics of tamping, a disassembly tool is designed to generate a thrust exceeding the disassembly force on the cone handle remaining in the cone hole of the pick arm, thereby completing the disassembly, avoiding the need to replace the pick arm, and reducing user costs.

[0005] The technical solution to achieve the objective of this invention is:

[0006] A method for removing a CDC-16 tamping pick with a broken cone handle includes the following steps:

[0007] Step S1: Estimate the dismantling force Q' required for the tamping pick used to break the cone handle;

[0008] Step S2: Based on the structural characteristics of tamping and the principle of force amplification by inclined plane, pre-disassembly is performed by inserting a wedge into the gap between the top of the flat square and the through hole of the waist-shaped groove.

[0009] Step S3: Analyze the pre-disassembly process to determine the optimal structure of the wedge;

[0010] Step S4: Apply a lateral thrust to the wedge of the optimal structure using an external power source, thereby removing the tamping pick with the broken cone handle.

[0011] Further, in step S1, the dismantling force Q' = 1.5Q, where Q is the minimum binding force between the pick and the arm of the broken cone-handle tamping pick, determined according to the following formula.

[0012] Q = p × π × d m ×l f ×μ

[0013] , where l f The length of the tamping pick support, μ, is the coefficient of friction between the tamping pick and its arm, and p is the combined pressure between the tamping pick and its arm with the broken cone shank. These values ​​are determined according to the following formula.

[0014]

[0015] E a E represents the elastic modulus of the pickaxe arm. i S is the elastic modulus of the tamping pick. a The flattening depth of the pickaxe arm, Sa = 1.6 × Ra a Ra a S represents the surface roughness of the pickaxe arm. i For the tamping depth using a pickaxe, Si = 1.6 × Ra i Ra i δ represents the surface roughness of the tamping pick, δ is the interference fit between the tamping pick and the pick arm, δ = ΔE × C, ΔE is the axial pressing displacement of the tamping pick, and C is the fit taper. a C is the stiffness coefficient of the pickaxe arm. i The stiffness coefficient of the tamping pick is determined according to the following formula.

[0016]

[0017]

[0018] , where d a γ is the outer diameter of the pickaxe arm. a For the pickaxe arm Poisson's ratio, d i For the inner diameter of the pickaxe used for tamping, γ i The Poisson's ratio and the average cone diameter (d) for tamping are determined by the following formulas.

[0019]

[0020] , where d f1 The minimum cone diameter for a conical interference fit, i.e., the diameter of the small end of the tamping pick, is d. f2 This is the diameter of the maximum cone, i.e., the diameter of the large end of the pick arm hole.

[0021] Furthermore, in step S3, by analyzing the pre-disassembly process, the total reaction force R of the pick arm on the wedge is established based on the force triangle of the wedge. 31 Functional relationship and the total reaction force R of the tamping pick on the wedge 21 The functional relationship is as follows:

[0022] R 31 =Pcos(α+φ2) / sin(α+φ1+φ2)

[0023] R 21 =Pcosφ1 / sin(α+φ1+φ2)

[0024] Where α is the slope of the wedge, Φ1 is the friction angle between the pick arm and the wedge, Φ2 is the friction angle between the wedge and the tamping pick, Φ3 is the friction angle between the tamping pick and the pick arm, and l f Let P be the length of the tamping pick support and P be the force of the wedge pressing in. Based on the force and moment balance conditions of the tamping pick, the following equilibrium equations are established:

[0025] ∑F X =(R 3B -R 3C cosφ3-R 12 sin(α+φ2)=0

[0026] ∑F Y =R 12 cos(α+φ2)-(R 3B +R 3C sinφ3-Q=0

[0027]

[0028] , where R 3B R 3C These are the support reactions of the pick arm on the small and large ends of the tamping pick, R respectively. 12 Let be the total reaction force of the wedge on the tamping pick, and b be the cantilever length of the tamping pick. After simplification, we get:

[0029]

[0030]

[0031] R 3C =R 3B -R 21 sin(α+φ2) / cosφ3

[0032] Thus, a functional relationship is established between the dismantling force Q' and the wedge pressing force P.

[0033]

[0034] Based on the functional relationship, combined with the minimum stroke of the wedge and the pressing force P, the optimal slope of the wedge is determined.

[0035] Furthermore, the finite element method was used to analyze the pre-disassembly process of the fracture cone handle tamping pick on the wedge with a determined inclination, to determine the maximum equivalent stress on the wedge and the minimum yield strength of the wedge material, taking into account both hardness and wear resistance, thereby determining the material of the wedge.

[0036] Furthermore, the wedge is an elliptical flat wedge with a cross-section that matches the through hole of the waist-shaped groove. The outer circumference of the middle part of the wedge has a slope extending to the small end, and the slope of the slope is α.

[0037] Furthermore, the thickness of the small end of the wedge is 0, 5, 10 or 15 mm.

[0038] Furthermore, in step S4, the external power source is a manual power source consisting of a hammer and a striking rod or a hydraulic cylinder.

[0039] By adopting the above technical solution, the present invention has the following beneficial effects:

[0040] (1) This invention estimates the dismantling force required for the tamping pick with a broken cone handle, cleverly utilizes the gap between the flat top and the through hole of the waist-shaped groove, designs a wedge as a dismantling tool based on the principle of force amplification of the inclined plane, and optimizes the structure of the wedge by analyzing the pre-dismantling process, thus determining the optimal structure of the wedge. Finally, under the action of an external power source, a lateral thrust is applied to the wedge with the optimal structure, generating a thrust exceeding the dismantling force on the cone handle remaining in the cone hole of the pick arm, thereby completing the dismantling, solving the industry problem, avoiding the need to replace the pick arm, and reducing the user's operating costs.

[0041] (2) The dismantling force of the present invention is 1.5 times the theoretical bonding force between the broken cone shank tamping pick and the pick arm. While ensuring that the broken cone shank tamping pick remaining in the pick arm can be removed, the dismantling force is reduced as much as possible, thereby reducing the structural requirements of the wedge.

[0042] (3) This invention establishes a functional relationship between the disassembly force Q' and the wedge pressing force P, thereby conveniently and quickly determining the optimal slope of the wedge.

[0043] (4) The present invention uses the finite element method to analyze the pre-disassembly process, accurately obtains the maximum equivalent stress on the wedge and the minimum yield strength of the wedge material, which facilitates the selection of wedge material that meets the requirements and improves the disassembly success rate.

[0044] (5) The wedge of the present invention is an elliptical flat wedge with a cross-section that is compatible with the through hole of the waist-shaped groove. When the external power source applies a thrust to the wedge, it relies on the self-positioning and guidance of the groove wall of the through hole of the waist-shaped groove to prevent the wedge from deviating during the pressing process, and ensure that the top thrust applied to the wedge is maximized to be converted into the thrust of the wedge inclined surface of the tamping pick for fracture.

[0045] (6) The small end of the wedge of the present invention has a variety of thicknesses and forms a variety of specifications to meet the different gaps between the top of the tamping pick and the top of the waist-shaped groove through hole, and has a wide range of applications.

[0046] (7) The external power source of the present invention is a manual power source or a hydraulic cylinder, which meets the needs of different scenarios and has a wide range of applications. Attached Figure Description

[0047] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0048] Figure 1 This is a cross-sectional view of the tamping pick and pick arm assembled according to the present invention;

[0049] Figure 2 This is a simplified diagram of the external structure of the tamping pick and pick arm assembled according to the present invention;

[0050] Figure 3 This is a mechanical structure analysis diagram of the present invention;

[0051] Figure 4 This is a schematic diagram of the wedge structure of the present invention;

[0052] Figure 5 This is a simplified structural diagram of the extraction method in Example 1;

[0053] Figure 6 This is a simplified structural diagram of the extraction method in Example 2.

[0054] The labels in the attached diagram are:

[0055] 1. Hammer for tamping; 2. Hammer arm; 3. Waist-shaped groove through hole; 4. Wedge; 4-1. Inclined surface; 5. Hammer; 6. Striking rod. Detailed Implementation

[0056] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0057] (Example 1)

[0058] like Figure 1 and Figure 2The assembly diagram of the CDC-16 tamping machine's tamping pick and pick arm shown includes a tamping pick 1, a pick arm 2, and a slotted through hole 3. The tamping pick 1 is interference-fitted into the pick arm 2. The slotted through hole 3 is formed on the pick arm 2. The top of the tamping pick 1 is conical and extends into the slotted through hole 3, with a gap between the top of the tamping pick 1 and the top of the slotted through hole 3. When the tamping pick breaks along the large end diameter of the cone handle, the lack of support from the pick's shoulder makes disassembly impossible due to the absence of a leverage point, rendering conventional hammering and pulling operations impossible. This embodiment provides a method for removing a broken cone handle tamping pick from a CDC-16 tamping machine, including the following steps:

[0059] Step S1: Estimate the dismantling force Q' required for the tamping pick used to break the cone handle;

[0060] Specifically, the dismantling force Q' = 1.5Q, where Q is the theoretical combined force between the pick and the arm of the tamping pick with the broken cone handle, determined according to the following formula.

[0061] Q = p × π × d m ×l f ×μ

[0062] , where l f The length of the tamping pick support, μ, is the coefficient of friction between the tamping pick and its arm, and p is the combined pressure between the tamping pick and its arm with the broken cone shank. These values ​​are determined according to the following formula.

[0063]

[0064] E a E represents the elastic modulus of the pickaxe arm. i S is the elastic modulus of the tamping pick. a The flattening depth of the pickaxe arm, Sa = 1.6 × Ra a Ra a S represents the surface roughness of the pickaxe arm. i For the tamping depth using a pickaxe, Si = 1.6 × Ra i Ra i δ represents the surface roughness of the tamping pick, δ is the interference fit between the tamping pick and the pick arm, δ = ΔE × C, ΔE is the axial pressing displacement of the tamping pick, and C is the fit taper. a C is the stiffness coefficient of the pickaxe arm. i The stiffness coefficient of the tamping pick is determined according to the following formula.

[0065]

[0066]

[0067] , where d a γ is the outer diameter of the pickaxe arm. a For the pickaxe arm Poisson's ratio, di The inner diameter of the tamping pick is d. In this embodiment, the tamping pick is a solid structure. i =0, γ i Poisson's ratio for tamping, d m The average cone diameter is determined by the following formula:

[0068]

[0069] , where d f1 The minimum cone diameter for a conical interference fit, i.e., the diameter of the small end of the tamping pick, is d. f2 The maximum cone diameter, i.e., the diameter of the large end of the pick arm hole, is the average cone diameter d in this embodiment. m It is 75mm.

[0070] In this embodiment, the elastic modulus E of the pickaxe arm a And the elastic modulus E of the tamping pick i All values ​​are taken as 210000 MPa, and the pickaxe arm Poisson's ratio γ. a And tamping picks Poisson's ratio γ i All values ​​are taken as 0.3, and the surface roughness Ra of the pick arm is... a and the surface roughness Ra of the tamping pick i All values ​​are taken as 1.6, the friction coefficient μ is 0.12, and the maximum driving distance of 3mm for tamping picks is taken as the axial driving displacement ΔE of the tamping pick. The taper C is 0.05, and the outer diameter d of the pick arm is... a The length of the tamping pick support is 110mm, and the length of the tamping pick support is l. f If the diameter is 120mm, then the required disassembly force Q' = 532079N.

[0071] Step S2: Combining the structural characteristics of tamping, and based on the principle of force amplification on inclined planes, such as... Figure 3 As shown, wedge 4 is inserted into the gap between the top of the flat square and the through hole of the waist-shaped groove for pre-disassembly;

[0072] Specifically, since the tamping pick is broken, there is no external leverage point, making it impossible to pull out its cone handle by applying external force. Analysis of the structure reveals that to prevent rotation of the tamping pick during operation, a slotted through-hole is machined into the pick arm, and a corresponding flat bar is machined into the top of the tamping pick. During installation, the flat bar is inserted into the slotted through-hole to prevent rotation. A small gap is left between the top of the flat bar and the slotted through-hole, but this space cannot directly accommodate equipment that can generate a pressure greater than the dismantling force Q'. Based on the principle of inclined plane force amplification, a wedge with a certain inclination can be inserted into this space. By applying an axial thrust to the wedge, the inclined plane generates a component force greater than the thrust, pushing the broken cone handle out.

[0073] Step S3: Analyze the pre-disassembly process to determine the optimal structure of the wedge;

[0074] Specifically, the total reaction force R of the pick arm on the wedge is established based on the force triangle of the wedge. 31 Functional relationship and the total reaction force R of the tamping pick on the wedge 21 The functional relationship is as follows:

[0075] R 31 =Pcos(α+φ2) / sin(α+φ1+φ2)

[0076] R 21 =Pcosφ1 / sin(α+φ1+φ2)

[0077] Where α is the slope of the wedge, Φ1 is the friction angle between the pick arm and the wedge, Φ2 is the friction angle between the wedge and the tamping pick, Φ3 is the friction angle between the tamping pick and the pick arm, and P is the pressing force of the wedge. The following equilibrium equations are established based on the force balance and moment balance conditions of the tamping pick:

[0078] ∑F X =(R 3B -R 3C cosφ3-R 12 sin(α+φ2)=0

[0079] ∑F Y =R 12 cos(α+φ2)-(R 3B +R 3C sinφ3-Q=0

[0080]

[0081] , where R 3B R 3C These are the support reactions of the pick arm on the small and large ends of the tamping pick, R respectively. 12 Let be the total reaction force of the wedge on the tamping pick, and b be the cantilever length of the tamping pick. After simplification, we get:

[0082]

[0083]

[0084] R 3C =R 3B -R 21 sin(α+φ2) / cosφ3

[0085] Thus, a functional relationship is established between the dismantling force Q' and the wedge pressing force P.

[0086]

[0087] Based on the functional relationship, combined with the minimum stroke and pressing force P of the wedge, the optimal inclination of the wedge is determined. In this embodiment, different inclination values ​​are substituted to calculate the corresponding pressing force P of the wedge and the minimum stroke of the wedge at that inclination. The results are shown in the table below. From the data in the table, it can be seen that when the inclination α is 1:8, P = 0.361Q' = 192081N, the wedge stroke is 24mm, and the pressure and stroke matching effect is optimal. Therefore, the inclination α of the wedge is determined to be 1:8.

[0088] slope The stroke of the wedge (mm) The pressing force (N) of the wedge. 1：6 18 216460 1：7 21 202243 1：8 24 192081 1：9 27 183625 1：10 30 177196

[0089] The finite element method was used to analyze the pre-disassembly process of a tamping pick with a fracture cone handle for a wedge with an inclination angle α of 1:8. When the wedge was subjected to a force of 192081N, the maximum equivalent stress on the wedge was 500.87MPa. Therefore, the minimum yield strength of the wedge material was 500.87MPa. In order to balance hardness and wear resistance, the wedge material in this embodiment was determined to be Hardox450.

[0090] like Figure 4 As shown, the wedge 4 is an elliptical flat wedge with a cross-section adapted to the through hole of the waist-shaped groove. A slope 4-1 extending to the small end is provided on the outer circumference of the middle section, with a slope of 1:8. When the wedge is inserted into the gap between the through hole of the waist-shaped groove and the flat iron, the self-positioning and guiding of the groove wall ensures that the wedge will not deviate during the pressing process, maximizing the conversion of the jacking force applied to the wedge into the thrust of the wedge's slope against the tamping pick. The end face of the small end of the wedge is rounded off from the outer circumference to reduce scraping of the groove wall of the through hole during axial advancement, minimizing the jacking force applied to the wedge. Simultaneously, due to various factors, the gap between the tip of the tamping pick and the tip of the waist-shaped groove is not a fixed value. Therefore, while maintaining the slope of the slope, the small end of the wedge has four different thicknesses d: 0mm, 5mm, 10mm, or 15mm, forming various specifications to meet the disassembly and assembly requirements of different tamping gaps, thus having a wide range of applications.

[0091] Step S4: As Figure 5 As shown, an artificial power source consisting of a hammer 5 and a striking rod 6 is used as an external power source to apply a lateral thrust to the wedge, thereby removing the tamping pick with the broken cone handle. This method not only has lower requirements for construction conditions but also has lower construction costs.

[0092] (Example 2)

[0093] The assembly structure of the tamping pick and pick arm of the CDC-16 tamping machine in this embodiment is the same as that in Embodiment 1, and the method for removing the tamping pick with the broken cone handle is also similar to that in Embodiment 1. The difference lies in step S4, such as... Figure 6As shown, the external power source uses a hydraulic cylinder 7. The hydraulic cylinder is fixedly installed on the pick arm, and the ejection mechanism of the hydraulic cylinder pushes the right side of the wedge. As the ejection mechanism of the hydraulic cylinder pushes the wedge to move continuously, the tamping pick is finally ejected. No manual operation is required, which reduces the labor intensity of workers and improves the extraction efficiency.

[0094] Based on the structural characteristics of the pick arm and the tamping pick itself, this invention calculates the interference fit force between the tamping pick cone handle and the pick arm cone hole. Utilizing the principle of force amplification by an inclined plane, a beveled elliptical flat iron is designed to meet usage requirements, enabling the disassembly of the tamping pick with a broken cone handle. The angle of the inclined plane is the optimal angle obtained through theoretical calculation. This angle allows for the generation of the maximum vertical component force with the minimum axial force under the minimum stroke, filling the gap in disassembly technology for the CDC-16 large railway track maintenance machinery with a broken cone handle. This improves user work efficiency and significantly reduces labor intensity. Simultaneously, because the broken cone handle is detachable, the replacement of the pick arm due to scrapping is reduced, significantly lowering user equipment operating costs and maintenance time. This ensures the timely and smooth progress of track construction and the quality of tamping operations, laying a solid foundation for the high-speed and stable operation of China's railways.

[0095] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for removing a CDC-16 tamping pick with a broken cone handle, characterized in that, Includes the following steps: Step S1: Estimate the dismantling force Q' required for the tamping of the broken cone handle; Step S2: Based on the structural characteristics of tamping and the principle of force amplification by inclined plane, pre-disassembly is performed by inserting a wedge into the gap between the top of the flat square and the through hole of the waist-shaped groove. Step S3: Analyze the pre-disassembly process to determine the optimal structure of the wedge; By analyzing the pre-disassembly process, a functional relationship is established between the disassembly force Q' and the wedge pressing force P. Where α is the slope of the wedge, Φ1, Φ2, and Φ3 are the friction angles, lf is the support length of the tamping pick, and b is the cantilever length of the tamping pick. Based on the functional relationship, combined with the minimum stroke of the wedge and the tamping force P, the optimal slope of the wedge is determined. The finite element method was used to analyze the pre-disassembly process of the fracture cone handle tamping pick for the wedge with a certain inclination, to determine the maximum equivalent stress and the minimum yield strength of the wedge material, thereby determining the material of the wedge. Step S4: Apply a lateral thrust to the wedge of the optimal structure using an external power source, thereby removing the tamping pick with the broken cone handle.

2. The method for removing a CDC-16 tamping pick with a broken cone handle according to claim 1, characterized in that: In step S1, the disassembly force Q' = 1.5Q, where Q is the theoretical combined force between the pick and the arm of the broken cone handle tamping pick.

3. The method for removing a CDC-16 tamping pick with a broken cone handle according to claim 1, characterized in that: The wedge is an elliptical flat wedge with a cross-section that matches the through hole of the waist-shaped groove. The outer circumference of the middle part of the wedge has a slope extending to the small end, and the slope of the slope is α.

4. The method for removing a CDC-16 broken cone handle tamping pick according to claim 3, characterized in that: The thickness of the small end of the wedge is 0, 5, 10 or 15 mm.

5. The method for removing a CDC-16 tamping pick with a broken cone handle according to claim 1, characterized in that: In step S4, the external power source is a manual power source consisting of a hammer and a striking rod or a hydraulic cylinder.

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