WO2024154151A1

WO2024154151A1 - Frugally designed jaw crusher

Info

Publication number: WO2024154151A1
Application number: PCT/IN2024/050043
Authority: WO
Inventors: Balakrishna Rao
Original assignee: Indian Institute of Technology Madras
Current assignee: Indian Institute of Technology Madras
Priority date: 2023-01-17
Filing date: 2024-01-17
Publication date: 2024-07-25
Anticipated expiration: 2025-07-17

Abstract

A frugally designed jaw crusher (100) for extracting minerals is disclosed. The jaw crusher includes an optimized flywheel (102), an optimized pitman frame (104) and an optimized rear wall(106). The flywheel has a peripheral flywheel portion (202) and a petalled web (206) with five petal-shaped openings connecting to a hub of the flywheel. 5 The petalled web includes spokes (204) of rounded rectangular cross section of width to height 2:1. The optimized pitman frame houses a bearing for an eccentric shaft (108) and extends in length down to a toggle seat (308). The toggle seat has a twin wall structure (306) formed by a triangular 4-ribbed construction of uniform wall thickness. The jaw crusher is frugally designed for reduced weight and improved strength, load bearing 10 capacity, better damping and reduced peak stress with more savings on material cost.

Description

FRUGALLY DESIGNED JAW CRUSHER

CROSS-REFERENCES TO RELATED APPLICATION

[0001] This application takes priority to Indian Provisional Patent Application No. 202341003454 titled “A FRUGALLY ENGINEERED JAW CRUSHER FOR EXTRACTION OF MINERALS” filed on January 17, 2023.

FIELD OF INVENTION

[0002] The present disclosure relates to jaw crusher, more particularly it relates to an improved jaw crusher with improved strength, load bearing capacity, better damping, reduced peak stress and frugal design for material saving.

DESCRIPTION OF THE RELATED ART

[0003] Jaw crushers are used in extraction of minerals and ores from and under Earth’s surface. Typical to the mining industry, the components of a jaw crusher are bulky in design in order to be robust. Therefore, the components have good potential to be frugally redesigned. Jaw crushers are used extensively as popular primary crushing equipment for minerals and aggregates. Hence, cost plays a very significant role due to high volumes, especially in aggregates production. The requirements of robustness, value and cost-saving makes the components of a jaw crusher prime candidates for a redesign using frugality principles to facilitate weight reduction of the overall equipment.

[0004] The jaw crusher works by breaking rocks under compression and impact between a fixed and a moving jaw. Jaw crushers are classified based on the pivot position of the moving jaw and the toggle type. Based on the pivot position, a jaw crusher can be classified as Blake type (pivot at the top), Universal type (pivot at the center) or Dodge type (pivot at the bottom). Based on the toggle type, a jaw crusher can be classified either as a single toggle jaw crusher or a double toggle jaw crusher.

[0005] Various publications have tried to address the problems encountered for reducing weights for the various components of the jaw crusher while enhancing its functionality. PCT publication 2018113959A1 discloses a jaw crusher having a movable jaw support frame configured to facilitate interchange between shim and wedge settings, the support frame is configured to minimize stress concentrations. US application 8757530B2 discloses a pitman of jaw crusher has an upper part, which includes an upper supporting point for supporting the pitman in the body of the jaw crusher, and a lower part having a lower supporting point for supporting the pitman in the body of the jaw crusher through a toggle plate. Chinese application 217747204U discloses a novel jaw crusher flywheel which comprises a rim, and a hub, a web plate, a spoke and a balancing weight which are arranged in the rim. Chinese application 218422965U discloses a novel jaw crusher with an adjustable jaw plate, which comprises a jaw crusher frame, a static jaw plate and a movable jaw body are arranged in the jaw crusher frame, and an adjusting device is arranged between the static jaw plate and the jaw crusher frame or/and between the movable jaw body and the jaw crusher frame.

[0006] Presently, there is a requirement for a frugal design for jaw crushers for weight reduction as well as streamlining the major components of the jaw crusher to facilitate the reduction of the total weight of the jaw crusher.

SUMMARY OF THE INVENTION

[0007] The present subject matter relates to a jaw crusher for extraction of minerals.

[0008] In one embodiment of the present subject matter, a jaw crusher for extraction of minerals. The jaw crusher includes a flywheel of optimized construction having a peripheral flywheel portion and a petalled web connecting to a hub of the flywheel. The petalled web includes five petal-shaped openings bounded by spokes of rounded rectangular cross section, the spokes having a width and a height and a width to height ratio of 2: 1, wherein the flywheel has a peak torque of 75 Nm/kg or more. The jaw crusher further includes a pitman frame for providing mounting surfaces for crusher plates, an eccentric shaft and a toggle mechanism including the pitman frame housing a bearing for the shaft and extending in length down to a toggle seat, the frame having a height to width ratio of 2: 1, and having a twin wall structure with side walls extending from the bearing location to the toggle seat and the toggle seat is formed by a triangular 4-ribbed construction. The jaw crusher also includes an optimized rear frame.

[0009] In various embodiments, the optimized rear frame is filleted with ribs and having uniform wall thickness.

[0010] In various embodiments, the spokes of the flywheel (102) have a section of width to height ratio of 2: 1. [0011] This and other aspects are described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention has other advantages and features, which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:

[0013] FIG. 1 illustrates a frugally designed jaw crusher, according to an embodiment of the present subject matter.

[0014] FIG. 2 illustrates the frugally designed flywheel of the jaw crusher, according to an embodiment of the present subject matter.

[0015] FIG. 3 illustrates the frugally designed pitman frame of the jaw crusher, according to an embodiment of the present subject matter.

[0016] FIGS. 4A and 4B illustrate the frugally designed rear wall/frame of the jaw crusher, according to an embodiment of the present subject matter.

[0017] FIGS. 5A, 5B and 5C illustrate the three design versions of the flywheel, according to an embodiment of the present subject matter.

[0018] FIGS. 6A, 6B and 6C illustrate the three design versions of the pitman frame, according to an embodiment of the present subject matter.

[0019] FIGS. 7A, 7B and 7C illustrate the different sections of the optimized flywheel.

[0020] FIGS. 8A-8E illustrate the different sections of the optimized pitman frame

[0021] FIGS. 9A, 9B and 9C illustrate the different sections of optimized flywheel.

[0022] Referring to the figures, like numbers indicate like parts throughout the various views.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

[0024] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of “a”, “an”, and “the” include plural references. The meaning of “in” includes “in” and “on.” Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.

[0025] The present subject matter describes a frugally designed jaw crusher with reduced weight and improved strength, load bearing capacity, better damping and reduced peak stress with more flexibility and savings on material cost. The jaw crusher in various embodiments may be a Blake-type single toggle with the flywheel, pitman frame and rear wall/frame of the jaw crusher being redesigned to reduce weight.

[0026] A jaw crusher for crushing mineral ores or rocks as illustrated in FIG. 1, in various embodiments of the subject matter. The jaw crusher 100 includes a flywheel 102 of optimized construction, an optimized pitman frame 104 for providing mounting surfaces for crusher plates, an eccentric shaft 108, a toggle mechanism 110 and an optimized rear wall 106. The flywheel 102 uses moment of inertia to store energy while rotating which is for providing extra energy required to crush rocks during the crushing stroke in a jaw crusher 100. Further, the flywheel also compensates for the drop in the speed of the shaft during crushing, hence optimized flywheel 102 has reduced weight while maintaining the moment of inertia.

[0027] In various embodiments, the optimized flywheel 102 illustrated in FIG. 2 includes a peripheral flywheel portion and a petalled web 206 that is connecting to a hub 208 of the flywheel 102. The petalled web 206 comprises five petal-shaped openings bounded by spokes 204 of rounded rectangular cross section and the spokes 204 have a width and a height and a width to height ratio of 2: 1. In the optimized flywheel 102, the height of the rounded rectangle is 30mm, the cross section of the rounded rectangle increases near the hub. The petalled web 206 creates a branching effect that facilitates in improving the damping and load bearing capacity of the flywheel 102 while reducing peak stress on the component. Further, the odd number of spokes 204 present in the petalled web 206 and reduced section thickness facilitates a significant increase in the value of endurance strength, reduction in overall stress as well as a more uniform distribution of stress throughout the component. The optimized flywheel uses biomimetics for redesigning the component leading to more material savings EMS of 0.05+0.03 = 0.08. In one embodiment, the optimized flywheel 102 has a peak torque of 75 Nm/kg or more. The optimized flywheel is casted with ASTM A48 (grey cast iron) material which has good shock absorption properties.

[0028] In various embodiments, the pitman frame is one of the heaviest components of the jaw crusher 100 and is configured to be of robust design. The optimized pitman frame 104 illustrated in FIG. 3 provides mounting surface for crusher plates, an eccentric shaft 108 and a toggle mechanism 110. The optimized pitman frame 104 includes a bearing for the shaft 108 at one end and extends in length to a toggle seat 308 with a height to width ratio of 2: 1. In various embodiments, the height h of the pitman frame is defined as the length of the frame measured from a center of the shaft opening to the bottom of the frame, and width is defined as. The optimized pitman frame 104 has a twin wall structure 304 with a wall thickness and side walls 306 extending from the bearing location to the toggle seat 308. Further, the toggle seat 308 formed by a triangular 4-ribbed construction 310. The pitman frame 104 incorporates a beaded rib design and rounded off comers to reduce stress on the component. The twin wall structure 304 is designed to be similar to the shape of lower jaw bone of many animals, including canines. In some embodiments, the material ASTM A352 (cast alloy steel) is utilized for casting the optimized pitman frame 104. As biomimetics is used for optimizing the pitman frame design there is savings of material EMS of 0.06+0.02 = 0.08.

[0029] In various embodiments, the optimized rear wall of the jaw crusher 100 holds up one of the ends of the jaw crusher and provides an assembling point for side plates. The other end is held up by a front wall. The rear wall also provides a mounting point for the toggle mechanism 110 as well as motor frame (not shown in picture) in the jaw crusher 100. The rear wall performs the function of conducting the crushing forces through the pitman frame 104, through the toggle 110 and into the side walls where foundation pads are assembled. The rear wall is also subjected to high levels of loading and requires strong material for casting. The optimized rear wall 106 as illustrated in FIGS. 4A and 4B is filleted 404 with ribs 402 to ensure less stress on the overall structure and having uniform wall (406) thickness of 25mm. The material ASTM A352 (alloy steel) is utilized for casting the optimized rear wall 106 and there is savings of material EMS of 0.03.

[0030] The jaw crusher optimization follows a frugal design approach which has several advantages over the present prior art. The frugal design is based on the factor of frugality that has yielded material savings of 8%, 7% and 30% while increasing the factor of safety by 35%, 71% and 18% in the flywheel, the Pitman and the rear frame/wall respectively over their base designs. Optimized designs for the flywheel, the pitman frame and the rear frame/wall contributed to weight savings of 49 Kg, 212 Kg, 368 Kg respectively with total weight reduction for the jaw crusher amounting to 678 Kg, which is 14.2% of the weight of the three components (the flywheels, the pitman frame and the rear wall) considered for redesign. For a 110 kW jaw crusher weighing approximately 22 metric tons, the weight saving equals about 3% of total weight. Reduction in total weight of the jaw crusher also leads to reduction in the running cost of the equipment. The factor of frugality of 1.87^{1 79},

1.76 and 1.63 is obtained for each of the components respectively based on the frugal design optimization.

[0031] Although the detailed description contains many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed herein. Various other modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the system and method of the present invention disclosed herein without departing from the spirit and scope of the invention as described here, and as delineated in the claims appended hereto.

EXAMPLES

[0032] EXAMPLE 1: Frugality Analysis for different designs versions of Flywheel

[0033] In a first design version of the flywheel, a simple design commonly available in the market is used featuring a flat profile for easy manufacturing. The flywheel has a periphery portion that is connected to the hub by 5 spokes, each spoke has a width of 158mm and the thickness of 60mm. In a second version of the flywheel, a spoke web connects the hub of the flywheel with the periphery. The spoke web has 4 openings bound by rounded rectangular cross section, the height of the rounded rectangle is 60mm. The third version is the optimized flywheel is described perviously. The three design versions of the flywheel are illustrated in FIG. 5.

[0034] The following table provides a comparison of the flywheel’s three versions of design. TABLE 1 : Frugality analysis for flywheel design

[0035] Wherein, N is fatigue based factor of safety that is dependent on endurance strength and which is provided as a ratio of maximum material stress to actual working stress, MS is the material saving, F is defined as factor of frugality and F^N is given by factor of frugality and factor of safety. [0036] As can be observed from TABLE 1, there are distinct differences in each design version with respect to stress, endurance, mass and other factors. For first design version the stress concentration at the base of each spoke and the torque applied at the periphery is transferred to the hub via the spokes. This version of the flywheel design displays the highest peak stress value and the lowest endurance strength value of the three designs. For second design version the concentration of stress is still at the base of each spoke similar to previous version but to a reduced extent. The peak von Mises stress values have gone down from 37.1 MPa in first version to 30.2 MPa in second version. The stress is also less due to reduction of material Since second version uses a simple design scheme to reduce mass, MSI = 0.05 and EMS = 0.05. The third design version as disclosed with reference to FIG. 2 presents the best performance with reduced mass, higher endurance and more savings on material.

[0037] EXAMPLE 2: Frugality Analysis for different designs versions of Pitman frame

[0038] In a first design version of the pitman frame, a simple design commonly available is used to satisfy assembly and packaging constraints, the general wall thickness for this version is maintained at 43mm, which includes the ribs. In a second version of the pitman frame, the design for the pitman frame was changed to allow weight reduction but the general wall thickness was increased to 50mm. Further, the geometry at the bottom portion of the pitman frame was also modified to accommodate a webbed rib design to facilitate easier core removal and to give better strength for casting. The third version is the optimized pitman frame is described previously. The three design versions of the pitman frame are illustrated in FIG. 6.

[0039] The following table provides a comparison of the pitman frame’s three design version.

TABLE 2: Frugality analysis for pitman design

[0040] As can be observed from TABLE 2, there are distinct differences in each design version with respect to stress, endurance, mass and other factors. For first design version the stress concentrations near the base of the frame. For second design version, due to changes in the design and rounding of edges shows reduction in stress for the overall frame and EMS is 0.06. The third design version presents the best performance with reduced mass, higher endurance and more savings on material.

[0041] EXAMPLE 3: Frugality Analysis for different designs versions of Rear wall /frame [0042] In a first design version of the rear frame/wall, a simple design based on available geometrical constraints with high wall thickness. In a second version of the rear frame/wall, the design for the rear frame/wall was changed to reduce unwanted material and bring complexity in shape. This version is described previously.

[0043] The following table provides a comparison of the rear frame’s two design version. TABLE 3: Frugality analysis for rear frame/wall design

[0044] As can be observed from TABLE 3, there are distinct differences in each design version with respect to stress, endurance, mass and other factors. For first design version the stress concentrations near bosses where the rear frame/wall is assembled with the side walls. For second design version, is better filleted with ribbed design with the stress mostly concentrated around the center of the rear wall/frame and SMS is 0.03 with higher F value.

[0045] FIGS. 7A, 7B and 7C illustrate the different sections of the optimized flywheel. FIGS. 8A-8E show the different sections of the optimized pitman frame. FIGS. 9A, 9B and 9C show the different sections of optimized rear wall.

Claims

WE CLAIM:

1. A frugally designed jaw crusher (100) for extraction of minerals, comprising: i. a flywheel (102) of optimized construction comprising a peripheral flywheel portion (202) and a petalled web (206) connecting to a hub (208) of the flywheel (102), wherein the petalled web (206) comprises five petal-shaped openings bounded by spokes (204) of rounded rectangular cross section, the spokes (204) having a width and a height and a width to height ratio of 2: 1, wherein the flywheel (102) has a peak torque of 75 Nm/kg or more; ii. a pitman frame (104) for providing mounting surfaces for crusher plates, an eccentric shaft (108) and a toggle mechanism (110) including: a. the pitman frame (104) housing a bearing (302) for the shaft and extending in length down to a toggle seat (308), the frame (104) having a height to width ratio of 2: 1, and having a twin wall structure (304) with side walls (306) extending from the bearing location to the toggle seat (308); and b. the toggle seat (308) formed by a triangular 4-ribbed construction (310); and iii. an optimized rear frame (106).

2. The jaw crusher (100) as claimed in claim 1, wherein the optimized rear frame (106) is filleted (404) with ribs (402) and having uniform wall (406) thickness.

3. The jaw crusher (100) as claimed in claim 1, wherein the spokes of the flywheel (102) have a section having width to height ratio of 2: 1.