EP3876691A1

EP3876691A1 - An arm unit configured for attaching a disc blade to a disc plough frame

Info

Publication number: EP3876691A1
Application number: EP19798272.1A
Authority: EP
Inventors: Johnson REGO; Gopal Kamble; Ajit Patil; Sankar RAMACHANDRAN
Original assignee: SKF AB
Current assignee: SKF AB
Priority date: 2018-11-09
Filing date: 2019-11-04
Publication date: 2021-09-15
Also published as: WO2020094578A1; CN113163706A; MX2021004556A

Abstract

The present disclosure discloses an arm unit (305) for attaching a disc blade to a disc plough and a method for casting the same. The arm unit (305) comprises a bearing housing section (310) joined to an arm section (315) formed using split-pattern casting. The method for casting the arm unit involves forming an arm unit pattern by fastening a bearing housing pattern to an arm section pattern. The bearing housing pattern may be of a standard geometry, whereas the arm section pattern may be customised based on the requirement of a customer. The arm unit pattern thus formed is further used for producing a mould for casting the arm unit. The bearing housing pattern is reusable with arm section patterns corresponding to arm sections of different geometries.

Description

AN ARM UNIT CONFIGURED FOR ATTACHING A DISC BUADE TO A DISC

PEOUGH FRAME

FIEED OF THE INVENTION

[001] The present disclosure relates to an arm unit for attaching a disc blade to a disc plough and a method for casting the arm unit using split-pattern casting.

BACKGROUND OF THE INVENTION

[002] Disc plough is a farming tool used for preparation of a seedbed before planting of crops for cultivation. Typically, the disc plough is a tillage implement mounted on a tractor. The tractor draws the tillage implement over the seedbed for overturning of soil and breaking down of clods in the soil. The disc plough frame typically comprises an attachment link, a beam, at least one furrow wheel, a plurality of disc blades and associated scrapers. The disc blades are attached to a hub assembly secured on the beam through an arm.

[003] Commercially, the bearing housing in a hub assembly and the arm are custom- designed based on customer requirement or market demand. Since no two custom designs are similar, individual pattern designs are required for casting each of the bearing housing and the arm. Due to the lack of availability of standard designs for the bearing housing, a manufacturer of the disc plough may get the bearing housing and the arm manufactured through external vendors. In another instance, the manufacturer may manufacture the bearing housing based on indigenous designs. For example, the design used in Africa may be different from the design used in Mexico.

[004] After manufacturing of the bearing housing, the manufacturer assembles various components such as shaft, bearings, seal and so on into the bearing housing, for forming the hub assembly. Consequently, the components may also need to be custom designed in order to match the geometry of the bearing housing. In one example, the bearing housing may be sourced from a first external vendor and the hub assembly is assembled by the manufacturer of the disc plough using components sourced from a second external vendor. As a result, the probability for occurrence of mismatch between the bearing housing and the components is high. Furthermore, manufacturing of customized bearing housing and components also increase the overall time and material cost for production of the disc plough.

[005] Therefore, standardization of the bearing housing and a manufacturing process for the same is required.

BRIEF SUMMARY OF THE INVENTION

[006] This summary is provided to introduce a selection of concepts in a simple manner that is further described in the detailed description of the disclosure. This summary is not intended to identify key or essential inventive concepts of the subject matter nor is it intended for determining the scope of the disclosure.

[007] An example of an arm unit configured for attaching a disc blade to a disc plough frame, wherein the arm unit is from one of a first series of arm units and a second series of arm units is disclosed. Each arm unit comprises a bearing housing section and an arm section forming a single entity. The bearing housing section of the first series of arm units and the second series of arm units are identical at least in geometry outside a connection area of the bearing housing section to the arm section, and the arm section of the first series of arm units and the second series of arm units are different at least in geometry.

[008] An example of a method for casting an arm unit configurable for attaching a disc blade to a disc plough frame is disclosed. The method comprises making an arm section pattern corresponding to an arm section. The method further comprises making a bearing housing pattern corresponding to a bearing housing section. The method further comprises joining the bearing housing pattern to the arm section pattern by means of a fastening mechanism to form an arm unit pattern. The method further comprises casting an arm unit using the arm unit pattern. The arm unit is a single entity comprising the bearing housing section and the arm section. The bearing housing pattern is reusable with arm section patterns corresponding to arm sections of different geometries.

[009] To further clarify advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof, which is illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. The disclosure will be described and explained with additional specificity and detail with the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

[0010] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:

[0011] FIG. 1A illustrates an arm assembly comprising bearing housing section and an arm section, for attaching a disc blade onto a disc plough frame, in accordance with one embodiment of the present disclosure;

[0012] FIG. IB illustrates a bearing housing section, in accordance with one exemplary embodiment of the present disclosure;

[0013] FIG. 1C illustrates an arm section, in accordance with one exemplary embodiment of the present disclosure;

[0014] FIG. ID illustrates a bearing housing section attached to the arm section, in accordance with one exemplary embodiment of the present disclosure;

[0015] FIG. 2 shows a method of casting an arm unit comprising the bearing housing section and the arm section, in accordance with one embodiment of the present disclosure;

[0016] FIG. 3 A illustrates a first series of arm units and second series of arm units, in accordance with one exemplary embodiment of the present disclosure;

[0017] FIG. 3B illustrates an arm unit, in accordance with one exemplary embodiment of the present disclosure; [0018] FIG. 3C illustrates an arm section pattern, in accordance with one exemplary embodiment of the present disclosure;

[0019] FIG. 3D illustrates a bearing housing pattern, in accordance with one exemplary embodiment of the present disclosure; and

[0020] FIG. 3E illustrates an arm unit pattern, in accordance with one exemplary embodiment of the present disclosure.

[0021] Further, persons skilled in the art to which this disclosure belongs will appreciate that elements in the figures are illustrated for simplicity and may not have been necessarily drawn to scale. Furthermore, in terms of the construction of the arm unit and/or the hub assembly, one or more components of the arm unit and/or the hub assembly may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION

[0022] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications to the disclosure, and such further applications of the principles of the disclosure as described herein being contemplated as would normally occur to one skilled in the art to which the disclosure relates are deemed to be a part of this disclosure.

[0023] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof. [0024] In the present disclosure, relational terms such as first and second, and the like, may be used to distinguish one entity from the other, without necessarily implying any actual relationship or order between such entities.

[0025] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or a method. Similarly, one or more elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other elements, other structures, other components, additional devices, additional elements, additional structures, or additional components. Appearances of the phrase “in an embodiment”,“in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The components, methods, and examples provided herein are illustrative only and not intended to be limiting.

[0027] The present disclosure relates to a method for manufacturing of an arm unit. The arm unit consists of a bearing housing section which is assembled to form a hub assembly, and an arm section for securing the bearing housing section onto a beam of a disc plough. In the following sections, disc plough and disc plough frame have been used interchangeably. The invention disclosed attempts to address the shortcomings associated with conventional manufacturing processes for hub assemblies. In particular, the method helps in standardizing the bearing housing section design while customizing the arm section for a given tillage implement.

[0028] Embodiments of the present disclosure will be described below in detail with reference to the accompanying figures. [0029] Referring to FIGS. 1A and IB, an arm assembly 100 comprising a bearing housing section 105 and an arm section 150, for attaching a disc blade (not shown) onto a disc plough frame is shown, in accordance with one embodiment of the present disclosure.

[0030] The bearing housing section 105 is made of a suitable material such as Spheroidal Graphite Iron (SG Iron). The bearing housing section 105 is essentially a hollow cylindrical element having a first end which is open and a second end which is closed. In the present embodiment, the first end has an increased diameter for seating of a shaft 110 extending through the bearing housing section 105 as shown. In one embodiment, the bearing housing section 105 is a three-side closed bearing housing section.

[0031] The shaft 110 is essentially an elongated solid circular component having a flange portion at one end. The flange portion has an outer diameter greater than the diameter of the first end of the bearing housing section 105, as shown, for securing a disc blade. More specifically, the flange portion consists two or more holes 112 for securing the disc blade through a nut and bolt mechanism. The shaft 110 is further provided with a seal groove on the elongated solid circular component, just below the flange portion of the shaft 110. The seal groove may be a small section of the shaft 110, which has an enlarged diameter compared to the remaining length of the elongated solid circular component.

[0032] The shaft 110 is configured to rotate coaxially with respect to a central axis of the bearing housing section 105, thereby rotating the disc blade secured to the flange portion. As used herein, the central axis is defined as an imaginary line at the center of a body about which the body rotates. The rotation of the shaft 110 is driven by a forward motion of a tractor to which the disc plough is attached. More specifically, the resultant forces acting on the disc blade mounted on the shaft 110 causes the rotation of the shaft 110 inside the bearing housing section 105.

[0033] The rotation of the shaft 110 inside the bearing housing section 105 is enabled using a bearing assembly 115. The bearing assembly 115 enables rotation by reducing friction between the shaft 110 and the bearing housing section 105. In the present embodiment, the bearing assembly 115 is mounted on the elongated portion of the shaft 110 located inside the bearing housing section 105. The bearing assembly 115 is mounted on the shaft 110 by pressing. In one example, the bearing assembly 115 may consist of pre-adjusted taper hub units arranged in a back-to-back manner. The bearing assembly 115 further comprises a spacer 120 for positioning the bearing assembly 115 on the shaft 110. The bearing assembly 115 is secured on the shaft 110 using a lock nut 125 at a specific torque, in order to achieve a required preload for the bearing assembly 115. Consequently, the bearing assembly 115 rotates along with the shaft 110 inside the bearing housing section 105. Loosening of the lock nut 125 due to vibrations is prevented using a cotter pin 130. Further, the bearing assembly 115 and hence the shaft 110 is held in position in the bearing housing section 105 using a collar 135. The collar 135 is essentially a mechanical stop provided near the first end of the bearing housing section 105. The hub assembly further comprises a seal 140 engaged with the seal grove on the shaft 110. The seal 140 prevents ingress of contaminants including, but not limited to, dust, mud and slurry into the bearing assembly 115. The seal 140 also prevents the leakage of lubricants out of the bearing assembly 115. The leakage of lubricants out of the bearing assembly 115 may be further prevented by a bearing seal (not shown) present inside the bearing assembly 115, in addition to the seal 140.

[0034] In the present disclosure, the bearing housing section 105 is designed to have a standard geometry (i.e., size and shape). The arm assembly 100 further comprises the arm section 150 for attaching the hub assembly to the disc plough frame. Referring to FIG. 1C, the arm section 150 is shown, in accordance with one exemplary embodiment of the present disclosure. The arm section 150 may have a customized design based on the make of the disc plough frame. For example, the hub assembly may be interfaced to the disc plough frame from a first manufacturer using an arm section of a first geometry, and to the disc plough frame from a second manufacturer using an arm section of a second geometry.

[0035] The bearing housing section 105 is casted along with the arm section 150 as a single entity (henceforth referred to as an arm unit) of same material as shown in FIG. ID. Further, the various components such as the shaft 110, the bearing assembly 115, the spacer 120, the lock nut 125, the cotter pin 130, the collar 135 and the seal 140 are assembled into the bearing housing section 105 for forming the hub assembly attached to the arm section 150.

[0036] Referring to FIG. 2, in conjunction with FIGS. 3A, 3B, 3C, 3D and 3E, a method 200 for casting an arm unit 305 from one of a first series of arm units 305a-l, 305a-2... 305a- n (collectively referred as 305a) and a second series of arm units 305b-l, 305b-2... 305b-n (collectively referred as 305b) is shown, in accordance with one embodiment of the present disclosure. The arm unit 305 comprises a bearing housing section 310 (also shown as bearing housing section 105) and an arm section 315 (also shown as arm section 150), as shown in FIG. 3B. The method 200 for casting the arm unit 305 is explained in steps 205 to 230 considering an example of a sand casting process.

[0037] The method begins at step 205.

[0038] At step 210, an arm section pattern 320 is made using a suitable material including, but not limited to, wood, plastic and metal. In the present disclosure, the arm section pattern 320 collectively refers to two pieces or halves of the arm section pattern, 320a and 320b, having contours similar to the arm section 315 as shown in FIG. 3C. The two pieces of the arm section pattern, 320a and 320b, when joined form a replica of the arm section 315. The arm section 315 may correspond to one of a first series of arm units 305a and a second series of arm units 305b, as shown in FIG. 3A. The arm sections of the first series of arm units 305a are identical arm sections of a first geometry, e.g., the arm sections may be straight in shape and of length 100 cm. Similarly, the arm sections of the second series of arm units 305b are identical arm sections of a second geometry, e.g., the arm sections may be arched shape and of length 75 cm. However, the bearing housing sections in both the first series of arm units and the second series of arm units are identical in geometry.

[0039] At step 215, a bearing housing pattern 325 is made using a suitable material including, but not limited to, wood, plastic and metal. In the present disclosure, the bearing housing pattern 325 collectively refers to two pieces or halves of the bearing housing pattern, 325a and 325b, having contours similar to the bearing housing section 310 as shown in FIG. 3D. The two pieces of the bearing housing pattern 325 when joined form a replica of the bearing housing section 310. Ideally, the arm section pattern 320 and the bearing housing pattern 325 are made of the same material.

[0040] At step 220, the arm section pattern 320 is further joined to the bearing housing pattern 325 using a fastening mechanism for forming an arm unit pattern 330. More specifically, a first piece of the arm unit pattern 330a is obtained my fastening the first piece of the arm section pattern 320a to the first piece of the bearing housing pattern 325a as shown in FIG. 3E. Similarly, a second piece of the arm unit pattern 330b is obtained my fastening the second piece of the arm section pattern 320b to the second piece of the bearing housing pattern 325b. In one example, the fastening mechanism used may be screws of the same material as the bearing housing section 310 and the arm section 315. The arm section pattern 320 and the bearing housing pattern 325 may be fastened onto a match plate, using the screws, to obtain the arm unit pattern 330.

[0041 ] At step 225, an arm unit 305 is casted using the arm unit pattern 330. Firstly, the arm unit pattern 330 is used for forming a mould. The mould may be made in a flask using sand. More specifically, the arm unit pattern 330 is used to create a cavity corresponding to the contours of the arm unit 305 in sand. The first piece of the arm unit pattern 330a is used to create a respective cavity in a drag (not shown in figures) of the mould. At first, the first piece of the arm unit pattern 330a is placed over a plane surface. Further, the drag is placed over the first piece of the arm unit pattern 330a and filled with sand. After filling, the sand in the drag is compacted such that an impression of the first piece of the arm unit pattern 330a is formed in the sand. The drag is further flipped over and a cope (not shown in figures) is positioned over the drag. Further, the second piece of the arm unit pattern 330b is aligned over the first piece of the arm unit pattern 330a for forming a respective cavity in the cope when filled with sand and compacted. The cope is also incorporated with a gating system. After compacting, the drag and the cope are separated for removing the first piece of arm unit pattern 330a and the second piece of arm unit pattern 330b respectively. Further, one or more cores may also be positioned within the cope and/or the drag for formation of internal cavities and reentrant angles in the final cast of the arm unit 305. In one example, the one or more cores are positioned using chaplets.

[0042] After placing the core, the cope is positioned over the drag again to form the mould. Further, molten metal is poured into the cavity of the mould through the gating system. In one example, the molten metal may be molten SG Iron. Subsequently, the mould yields the cast of the arm unit 305 comprising the bearing housing section 310 and the arm section 315, upon cooling, i.e., after solidifying. The cast of the arm unit 305 may be taken out of the mould by breaking open the mould. The cast of the arm unit 305 may be further machined before assembling the various components into the bearing housing section. The bearing housing pattern is reusable with arm section patterns corresponding to arm sections of different geometries. For example, the bearing housing pattern 325 may be reused with arm section pattern 320a or arm section pattern 320b. It must be noted that the reusability of the bearing housing pattern 325 is not limited to arm section pattern 320a or arm section pattern 320b, but may be reused with more arm section patterns of different geometries.

[0043] The method ends at step 230.

[0044] It must be noted that when an arm section pattern corresponding to the first series of arm units is joined to the bearing housing pattern, a first arm unit pattern is formed. Similarly, when an arm section pattern corresponding to the second series of arm units is joined to the bearing housing pattern, a second arm unit pattern is formed. In other words, the bearing housing section of the first series of arm units and the second series of arm units are identical in geometry outside their connection area to the arm section, and the arm section of the first series of arm units and the second series of arm units are different in geometry. Therefore, the bearing housing pattern may be reused with arm section patterns of different geometry. The arm section pattern may be customized based on customer or market demand, for different arm unit designs while using the same design for the bearing housing section. It is to be noted that the bearing housing section is closed on three-sides. The three-sided closed design ensures that less contamination enters the bearing housing section.

[0045] The method of manufacturing disclosed herein, provides flexibility in meeting design requirements for specific purposes by standardizing the sizing of the bearing housing section and customizing the arm section. Consequently, the number of patterns used for the production of bearing housing sections is reduced. Further, separate moulds are not required for casting of the bearing housing section and the arm section. Furthermore, the components used in the hub assembly may also be standardized for a given size of bearing housing section. As a result, the overall manufacturing cost is reduced compared to existing manufacturing methods. The use of standardized components also reduce the financial and material loss due to mismatch between components and the bearing housing section.

[0046] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. [0047] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.

Claims

WE CLAIM:

1. An arm unit (305) configured for attaching a disc blade to a disc plough frame, wherein the arm unit (305) is from one of a first series of arm units (305a-l, 305a-2... 305a-n) and a second series of arm units (305b-l, 305b-2... 305b-n), the arm unit (305) comprising:

a bearing housing section (310) and an arm section (315) forming a single entity of uniform material, wherein the bearing housing section (310) of the first series of arm units (305a-l, 305a-2... 305a-n) and the second series of arm units (305b-l, 305b-2... 305b-n) are identical in geometry outside a connection area of the bearing housing section (310) to the arm section (315), and wherein the arm section (315) of the first series of arm units (305a-l, 305a- 2... 305a-n) and the second series of arm units (305b-l, 305b-2... 305b-n) are different in geometry.

2. The arm unit as claimed in claim 1, further comprising a shaft assembled inside the bearing housing section, wherein the shaft is configured to rotate coaxially with respect to a central axis of the bearing housing section.

3. The arm unit as claimed in claim 2, wherein the shaft is fitted with a bearing assembly for enabling rotational movement of the shaft inside the bearing housing section.

4. The arm unit as claimed in claim 1, wherein the arm section is made based on an arm section pattern and the bearing housing section is made based on a bearing housing pattern.

5. The arm unit as claimed in claim 4, wherein the arm section pattern and bearing housing pattern are joined to form an arm unit pattern.

6. The arm unit as claimed in claim 5, wherein the arm unit is casted from the arm unit pattern to form as the single entity of uniform material.

7. The arm unit as claimed in claim 1, wherein the bearing housing section is a three-side closed bearing housing section.

8. A method for casting an arm unit configurable for attaching a disc blade to a disc plough frame, the method comprising:

making an arm section pattern corresponding to an arm section; making a bearing housing patern corresponding to a bearing housing section; joining the bearing housing pattern to the arm section pattern by means of a fastening mechanism to form an arm unit patern; and

casting an arm unit using the arm unit pattern, wherein the arm unit is a single entity comprising the bearing housing section and the arm section, and wherein the bearing housing pattern is reusable with arm section patterns corresponding to arm sections of different geometries.

9. The method as claimed in claim 8, further comprising forming a mould using the arm unit pattern.

10. The method as claimed in claim 9, further comprising pouring molten metal into a cavity of the mould, wherein the cavity of the mould defines a contour of the arm unit.

11. The method as claimed in claim 10, further comprising cooling the molten metal in the mould for casting the arm unit.

12. The method as claimed in claim 8, further comprising assembling a shaft inside the arm unit, wherein the shaft is configured to rotate coaxially with respect to a central axis of the bearing housing section.

13. The method as claimed in claim 12, wherein the shaft is fited with a bearing assembly for enabling rotational movement of the shaft inside the bearing housing section.

14. The method as claimed in claim 8, wherein the bearing housing section is a three-side closed bearing housing section.