GB1588249A

GB1588249A - Jaw plate structure for jaw crushers

Info

Publication number: GB1588249A
Application number: GB5192177A
Authority: GB
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 1977-07-13
Filing date: 1977-12-14
Publication date: 1981-04-23
Also published as: DE2755426A1; JPS5419256A; BR7708276A; FR2397232B1; AU3138377A; DE2755426C2; FR2397232A1; JPS5723542B2; AU509363B2; CA1091207A

Description

(54) JAW PLATE STRUCTURE FOR JAW CRUSHERS (71) We, KAWASAKI JUKOGYO KABUSHIKI KAISHA, a company organized and existing under the Laws of Japan of 14, Higashikawasaki-Cho- 2-Chome, Ikuta-Ku, Kobe Shi, Hyogo-Ken, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to crushers, to primary crushers, and to jaw crushers or jaw breakers for crushing bulk materials such as rock and ores. More specifically, the invention deals with an improved jaw plate structure for use in the opposed, coacting jaws of jaw crushers such as those of the overhead eccentric or single toggle type or the Blake type.

The pair of opposed jaw plates of a jaw crusher are usually provided with corrugated crushing surfaces so that the bulk material fed may be readily crushed therebetween. The ridges of the corrugated crushing surfaces are, of course, subject to more rapid wear than their furrows or grooves in the case where the jaw plates are of homogeneous material. As a consequence, the crushing surfaces of such jaw plates readily become flat. This is undesirable since the crushing performance of the jaw crusher generally declines with the progress of the flattening of the crushing surfaces. until the particle size of the product becomes far greater than the setting.

The jaw plates with their corrugated crushing surfaces have customarily been cast from such materials as high manganese cast steel, low-alloy cast steel, and high chromium cast irons. Of these materials, high manganese cast steel and low-alloy cast steel are more ductile than high chromium cast iron and therefore comparatively immune to fracture but are rather unsatisfactory in wear resistance. High chromium cast irons, on the other hand, are more wear-resistant than high manganese cast steel or low-alloy cast steel but, at the same time, are more brittle and therefore more vulnerable to fracture.

In view of the above explained properties of the listed steel materials, a proposal has been made in Japanese Utility Model Application Laid Open No. 48-101260 (101260/1973) to provide a jaw plate comprising a base which is cast from high manganese cast steel or low-alloy cast steel. and which has a corrugated crushing surface, and a multiplicity of blocks of high chromium cast iron which are embedded in the ridges of the crushing surface of the base. According to this known jaw plate structure. the ridges of the corrugated crushing surface are more wear-resistant than its furrows, so that the difference in height between the ridges and furrows can be maintained for a greater period of time than with the jaw plates of homogeneous material.

A problem has been encountered. however, in the dimensioning of the jaw plates according to the above mentioned Japanease utility model application. Since jaw crushers in general are required to handle materials of widely varying hardness and other properties; the dimensions of the jaw plates (i.e.. those of the bases and the blocks) have been determined on a purely empirical basis. The performance and durability of the jaw plates have therefore not been truly satisfactory.

It is an object of this invention to improve the crushing performance of the jaw plates of the type disclosed in the aforementioned Japanese utility model application.

Another object of the invention is to increase the useful life of the jaw plates ofthe above specified type.

The invention is based upon the discovery that the best possible crushing performance and the longest possible service life can be derived from a jaw plate of the type under consideration only when the latter is manufactured to some pertinent dimensional specifications. Thus, in accordance with the invention, such pertinent dimensions of the jaw plate are specified in relation to the pitch of the corrugations of its crushing surface. The jaw plate of this invention has the distinct advantage that the ridges and furrows of its crushing surface are worn at approximately the same rate. This means that the desired difference in height between the ridges and furrows of the crushing surface is maintained for an extended length of time, so that the performance of the jaw plate does not deteriorate with the progress of its wear.

According to the present invention, there is provided a jaw plate structure for use in the opposed, coacting jaws of the jaw crusher, comprising a base of relatively ductile material having a crushing surface which is corrugated to provide alternating ridges and furrows with a preselected pitch (P), there being a series of recesses of generally rectangular shape in the crushing surface aligned along each ridge thereon, each recess having a width (W) ranging from 0.2 to 0.8 times the pitch (P) and the length (L) ranging from 0.2 to 3.00 times the pitch (P), each series of recesses having spacing gaps (S) therebetween ranging from 0.05 to 0.50 times the pitch (P), a plurality of blocks each formed of more wear-resistant material than the base and fitted in one of the respective recesses in the crushing surface of the base, each block having an exposed surface shaped to conform to the shape of each ridge of the crushing surface and having a portion projecting beyond both lateral edges of the base bounding the open end of each recess, the projecting portion of each block having a height (H) ranging from 0.17 to 1.0 times the pitch (P), and means for securing the blocks to the base.

The invention will now be described by way of example with reference to the accompanying drawings, in which: FIGURE lisa side elevation, in vertical section, schematically illustrating an example of a jaw crusher having jaw plates which can be constructed in accordance with the present invention; FIGURE 2 is a perspective view of the jaw plate structure embodying the principles of the invention; FIGURE 3 is a relatively enlarged, fragmentary plan view of the jaw plate structure of FIGURE 2; FIGURE 4 is a fragmentary sectional view of the jaw plate structure taken on the line IV-IV of FIGURE 3; and FIGURE 5 is a view similar to FIGURE 4 but showing a modification of the embodiment of FIGURES 2,3 and 4.

Referring in detail to the above drawings and initially to FIGURE 1 thereof, there is shown a jaw crusher of the overhead eccentric or single toggle type generally designated by reference numeral 10. The jaw crusher 10 comprises a stationary jaw 11 and a movable or "swinging" jaw 12 which are disposed opposite to each other to define therebetween the usual crushing cavity having a feed inlet 13 at the top and a product outlet 14 at the bottom.

The stationary jaw 11 has a jaw plate 15 which is shown to be composed of a plurality of separate sections and which is bolted or otherwise fastened to a frame 16 in vertical disposition.

The movable jaw 12 has a jaw plate 17 which is likewise shown to be composed of a plurality of sections and which is bolted or otherwise fastened to a jaw support 18 disposed at its lower end near the lower end of the stationary jaw 11 and inclined away from the stationary jaw. At its top end, the movable jaw support 18 is rotatably coupled via a ball bearing 19 to an eccentric shaft 20 which in turn is coupled eccentrically to a flywheel 21 rotated by a suitable drive mechanism (not shown). Also included in the jaw crusher 10 are a toggle mechanism 22 having a toggle member 23 extending between. and fitted in the bottom end of the movable jaw support 18 and a frame 24, and a spring assembly 25 comprising a coiled compression spring 26 and a tension rod 27 for biasing the movable jaw 12 away from the stationary jaw l I.

Thus. as the flywheel 21 is rotated by the drive mechanism, the movable jaw 12 "swings" in a fashion peculiar to the jaw crusher and coacts with the stationary jaw 11 to crush rock, ores or other bulk material. This bulk material is fed into the machine through the feed inlet 13, and the crushed product is discharged out of the product outlet 14.

The construction and operation of the overhead eccentric jaw crusher 10 as so far described have been well known in the art, and therein lies no feature of this invention. The invention is specifically directed to the jaw plate structure, shown in FIGURE 2 and therein generally labelled 30. that can be used as the stationary or the movable jaw plate 15 or 17 or as one of the constituent sections of either jaw plate.

With reference now directed to FIGURES 2. 3 and 4, the jaw plate structure 30 in accordance with this invention comprises a base 3 1 and a plurality of multiplicity of substantially rectangular blocks 32 of wear-resistant material received in respective recesses 33 formed in the base. Preferably cast from such comparatively ductile material as high manganese cast steel or low-alloy cast steel and heat-treated, the base 31 has a crúshing surface 34 which is corrugated to form alternating curved ridges 35 and furrows 36; The recesses 33 of generally rectangular shape are formed in the crushing surface 34 of the base 31 so as to be disposed along the ridges 35 thereon.

Although the recesses 33 are shown to be aligned in both of the directions parallel and transverse to the corrugations 35 and 36 of the crushing surface 34, the recesses may be arranged in a staggered or zigzag fashion in the transverse direction. It is of absolute necessity, however, that the recesses 33 be aligned along each ridge 35 of the crushing surface 34.

The blocks 32 fitted into the recesses 33 should be made of more wear-resistant material than the base 31, such as, preferably, high chromium cast iron, which may be heat-treated as required. As will be best seen from FIGURE 4, each block 32 has an exposed surface 37 which is curved to conform to the shape of each ridge 35 of the crushing surface 34, so that the ridges are formed by both the base and the blocks.

The base 31 and the blocks 32, if they are castings as aforesaid, are finished by grindin, and each block is fitted into one of the recesses 33 in the base with constant clearance C around the block. The blocks 32 are secured to the base 31, for example, by means of a suitable synthetic resin adhesive, indicated at 38 in FIGURE 4, which is filled in the gaps therebetween.

Shown at 39 in FIGURES 3 and 4 are grooves of constant depth formed in the rear surface 40 of the base 31 in parallel spaced relationship to each other. These grooves are disposed sustantially in register with the furrows 36 of the crushing surface 34 and are intended for use in mounting the jaw plate structure 30 in position on the crusher 10.

In accordance with this invention some pertinent dimensions of the jaw plate structure 30 of the above described configuration are specified as follows in relation to the pitch P (FIGURE 4) of the corrugations 35 and 36 of the crushing surface 34 in order to derive the best possible crushing performance and enduring quality therefrom. The actual length of the pitch P of the crushing surface corrugations is subject to change depending upon the size of the feed material and of the processed product. Roughly speaking, however, this pitch can be in the range of 200 to 250 millimeters for coarse crushing, 90 to 200 millimeters for intermediate crushing. and 40 to 90 millimeters for fine crushing.

The width W and the length L of each recess 33 in the base 31 range from 0.2 to 0.8 times and from 0.2 to 3.00 times the pitch P respectively. The spacing gap S between any two adjacent recesses 33 of each series ranges from 0.05 to 0.50 times the pitch P. The height H of the portion 41 of each block 32 which projects beyond the opposite lateral edges 42 of the base 31 bounding the open end of each recess 33 ranges from 0.17 to 1.0 times the pitch P.

Furthermore, the depth D of each recess 33 (as measured from the lateral edges 42 down to the bottom of the recess) preferably ranges from 0.1 to 1.33 times the pitch P. The thickness T of the portion 43 of the base 31 lying between the recesses 33 and the grooves 39 ranges from 0.03 to 0.50 times the pitch P. The clearance C with which each block 32 is fitted in one of the recesses 33 ranges from 0.01 to 0.10 times the pitch P. Although the dimensions of each block 32 are not specifically set forth except for the height H of its portion 41, the block dimensions can be easily computed from the above specified dimensions of each recess 33 and clearance C.

The width W of each recess 33 is set in the range of from 0.2 to 0.8 times the pitch P because. at widths less than 0.2 times the pitch P, the corresponding width of each block 32 would be so small that the furrow portions of the base 31 would suffer rapid wear. resulting in the excessive protrusion of the blocks 32 out of the crushing surface 34, especially in the case of jaw plates designed for fine crushing. Such protruding blocks would easily fracture, and the performance and durability of the jaw plates would be materially reduced. If the width W of each recess 33 were more than 0.8 times the pitch P, on the other hand, then the corresponding width of the furrow portions 36 of the base 31 would be so reduced that the desired difference in height between the ridges 35 and furrows 36 of the crushing surface 34 would not be maintained for any extended length of time.

The length L of each recess 33 is also set in the range of from 0.2 to 3.00 times the pitch P.

This is because. if the recess length L were less than 0.2 times the pitch P. the corresponding length of each block 32 would be so small that an unnecessarily large number of such blocks would have to be embedded in each ridge 35 of the crushing surface 34, thereby causing an increase in the manufacturing cost of the jaw plate. Alternatively, such reduction in the length L of each recess 33 might result in a corresponding increase in the spacing gap S between the recesses of each series. In this case, the base portions lying between the recesses of each series would suffer rapid wear, again resulting in the excessive protrusion of the blocks 32 out of the crushing surface 34. and the worn base portions would form pockets in which the material would easily be caught while being crushed.If the recess length L were more than 3.00 times the pitch P, on the other hand. then the blocks 32 of correspondingly increased length would be vulnerable to fracture.

The spacing gap S between any two adjacent ones of the recesses 33 of each series is specified as being in the range of from 0.05 to 0.50 times the pitch P. The reason for this is that. should the spacing gap S be less than about 0.05 times the pitch P, the molten metal would not flow smoothly in the mold during the casting of the jaw plate base 31. resulting in the production of defective articles. The spacing gap S of more than about 0.50 times the pitch P is also undesirable for the reasons set forth already in conjunction with the length L of each recess 33.

The height H of the projecting portion 41 of each block 32 is set in the range of from 0.17 to 1.0 times the pitch P. If the height H were less than 0.17 times the pitch P. there would not be a sufficient difference in height between the ridges 35 and furrows 36 of the crushing surface 34. resulting in poor crushing performance. If the height H were more than 1.0 times the pitch P. on the other hand. then there would be too great a difference in height between the ridges and furrows of the crushing surface to cause smooth flow of the material down the crushing cavity of the jaw crusher. The material might then be scattered about while being crushed,and the blocks 32 would be vulnerable to fracture or damage.

The depth D of each recess 33 is specified as ranging from 0.1 to 1.33 times the pitch P. If the depth D were less than about 0.1 times the pitch P. the blocks 32 fitted in the recess 33 would be of such small thickness that they would be susceptible to fracture or damage and might even be thrown out of the recesses in use. If the depth D were more than 1.33 times the pitch P, on the other hand. then unnecessarily large amounts of materials would have to be used for the manufacture of the base 3 1 and the blocks 32.

The thickness T of the base portion 43 between the recesses 33 and the grooves 39 is set in the range of from 0.03 to 0.50 times the pitch P. If the thickness T were less than 0.03 times the pitch P. the base 31 would be difficult to manufacture by casting and might be fractured in use. If the thickness T were more than 0.5 times the pitch P. on the other hand. then an unnecessarily large amount of material would be required for the manufacture of the base 31.

The clearance C with which each block 32 is fitted in the respective recess 33 is set in the range of from 0.0 l to O. l 10 times the pitch P. If the clearance C were less than 0.01 times the pitch P. the amount of an adhesive filled into the clear space would be insufficient to securely retain each block 37 in the recess 33. On the contrary. if the clearance C were more than 0. l times the pitch.P. the amount of an adhesive filled into the clear space would be too much to securely retain each block in the recess. In either case. therefore. the blocks might be dislodged out of the recesses in use.

Having thus set forth the grounds on which are based the dimensional specifications of the jaw plate structure 30 in accordance with this invention. it is clear that the jaw plate structure is well calculated to attain the above stated objectives. In order to demonstrate this fact.

several different pairs of jaw plates were manufactured in accordance with the teachings of this invention and were put to practical tests as to their crushing performance and durability.

The test results were further compared against the results of similar tests conducted on prior art pairs of jaw plates.

For these tests. our sample pairs of jaw plates I. II. III and IV were manufactured in accordance with the invention. with the respective sets of dimensions specified in the table below. I and II brine intended for fine crushing and II and IV for coarse crushing. Also. two prior art pairs of jaw plates V (for fine crushing) and VI (for coarse crushing) were employed which were both cast solely from high manganese steel. with corrugations on their crushing surfaces similar to the corrugations on the jaw plates of this invention. The difference in height between the ridges and furrows of the crushing surfaces was 25 millimeters in the prior art jaw plates V and 60 millimeters in the prior art jaw plates VI. Mounted on one and the same jaw crusher. the pairs of jaw plates of the invention and the prior art were used for ore crushing under the same working conditions to determine their per-hour capacities and wear ratios between the ridges and furrows of the crushing surfaces. The results are tabulated in the following table.

Dimensions, mm Ore crushing Wear ratio Intended capacity, between ridges use P W L S H D C tons per hour and furrows Invention I Fine 30 22 90 10 18 40 1 35 1.5:1 crushing (0.73p) (3.00p) (0.33p) (0.60p) (1.33p) (0.03p) II Fine 50 33 100 15 20 45 0.9 45 1.4:1 crushing (0.66p) (2.00p) (0.30p) (0.40p) (0.90p) (0.02p) III Coarse 180 100 108 20 38 90 1.5 550 1:1 crushing (0.56p) (0.60p) (0.11p) (0.21p) (0.50p) (0.01p) IV Coarse 240 120 167 25 40 120 3.0 650 1:1 crushing (0.50p) (0.69p) (0.10p) (0.17p) (0.50p) (0.01p) Prior Art V Fine 30 ... ... ... ........... .... 30 5:1 crushing VI Coarse 180 .. ................ .................. 500 3:1 crushing It will be readily seen from the above table that the jaw plates constructed in accordance with this invention serve to materially increase the capacity of jaw crushers.Moreover, the ridges and furrows of the inventive jaw plates are worn at a substantially even ratio; indeed, in the inventive jaw plates designed for coarse crushing, hardly any difference-exists in the rates of wear of the ridges and furrows. This is in marked contrast to the extremely uneven wear of the ridges and furrows of the prior art jaw plates. It is therefore apparent that the useful life of the inventive jaw plates is significantly longer than that of the prior art.

In FIG. 5 is shown a slight modification of the above described jaw plate structure 30, in which modification each block 32a of wear-resistant material has a plurality of grooves 45 formed in its lateral surfaces in parallel spaced relationship to each other and in parallel relationship to the plane of the jaw plate structure. These grooves are intended to receive the synthetic resin adhesive 38 as the latter is filled into the gaps between each block 32a and the surrounding recess walls of the base 31. In this manner the blocks 32a will be retained in the respective recesses 33 still more positively than the blocks 32 having no such grooves. It is to be understood, however, that the illustrated grooves 45 are by way of example only and can be replaced by other depressions of any desired shape or arrangement.

desired shape or arrangement.

WHAT WE CLAIM IS: 1. A jaw plate structure for use in the opposed, coacting jaws of a jaw crusher, comprising a base of relatively ductile material having a crushing surface which is corrugated to provide alternating ridges and furrows with a preselected pitch (P), there being a series of recesses of generally rectangular shape in the crushing surface aligned along each ridge thereon, each recess having a width (W) ranging from 0.2 to 0.8 times the pitch (P) and a length (L) ranging from 0.2 to 3.00 times the pitch (P), each series of recesses to 0.50 times the pitch (P), each series of recesses having spacing gaps (S) therebetween ranging from 0.05 to 0.50 times the pitch (P), a plurality of blocks each formed or more wear-resistant material than the base and fitted in one of the respective recesses in the crushing surface of the base, each block having an exposed surface shaped to conform to the shape of each ridge of the crushing surface and having a portion projecting beyond both lateral edges of the base bounding the open end of each recess, the projecting portion of each block having a height (H) ranging from 0.17 to 1.0 times the pitch (P). and means for securing the blocks to the base.

2. A jaw plate structure according to claim 1, wherein each recess in the crushing surface of the base has a depth (D) ranging from 0.1 to 1.33 times the pitch (P).

3. The jaw plate structure according to claim 1 or claim 2, wherein the base has a plurality of grooves of constant depth formed in its surface opposite to the crushing surface. and wherein the portion of the base lying between the recesses and the grooves has a thickness (T) ranging from 0.03 to 0.50 times the pitch (P).

4. The jaw plate structure according to any one of the preceding claims wherein each block is received with clearance (C) in a respective one of the recesses in the crushing surface of the base. and wherein the securing means comprises an adhesive filled into the clearance.

5. The jaw plate structure according to claim 4. wherein the clearance (C) ranges from 0.01 to 0.10 times the pitch (P).

6. The jaw plate structure according to claim 4, wherein each block has depressions formed in its lateral surfaces for receiving the adhesive.

7. The jaw plate structure according to any one of the preceding claims, wherein the base is a casting of material selected from the group consisting of high manganese cast steel and low-alloy steels.

8. The jaw plate structure according to any one of the preceding claims wherein each block is a casting of high chromium iron.

9. A jaw plate structure for use in the opposed. coacting jaws of a jaw crusher. comprising a base of relatively ductile material having a crushing surface which is corrugated to provide alternating ridges and furrows with a preselected pitch (P). there being a series of recesses of generally rectangular shape in the crushing surface aligned along each ridge thereon. each recess having a width (W) ranging from 0.2 to 0.8 8 times the pitch (P) and a length (L) ranging from 0.2 to 3.00 times the pitch (P). each series of recesses having spacing gaps (S) therebetween ranging from 0.05 to 0.50 times the pitch (P). a plurality of blocks each formed of more wear-resistant material than the base and fitted in one of the respective recesses in the crushing surface of the base. having a clearance (C) between the inner side walls of the recess and the side walls of the block. said clearance (C) ranging from 0.01 to 0.10 times the pitch (P). each block having an exposed surface shaped to conform to the shape of each ridge of the crushing surface and having a portion projecting beyond both lateral edges of the base bounding the open end of each recess. the projecting portion of each block having a height (H) ranging from 0.17 to 1.0 times the pitch (P). and means for securing the blocks to the base. the securing means being an adhesive filled into the clearance (C).

10. The jaw plate structure substantially as hereinbefore described with reference to and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. It will be readily seen from the above table that the jaw plates constructed in accordance with this invention serve to materially increase the capacity of jaw crushers. Moreover, the ridges and furrows of the inventive jaw plates are worn at a substantially even ratio; indeed, in the inventive jaw plates designed for coarse crushing, hardly any difference-exists in the rates of wear of the ridges and furrows. This is in marked contrast to the extremely uneven wear of the ridges and furrows of the prior art jaw plates. It is therefore apparent that the useful life of the inventive jaw plates is significantly longer than that of the prior art. In FIG. 5 is shown a slight modification of the above described jaw plate structure 30, in which modification each block 32a of wear-resistant material has a plurality of grooves 45 formed in its lateral surfaces in parallel spaced relationship to each other and in parallel relationship to the plane of the jaw plate structure. These grooves are intended to receive the synthetic resin adhesive 38 as the latter is filled into the gaps between each block 32a and the surrounding recess walls of the base 31. In this manner the blocks 32a will be retained in the respective recesses 33 still more positively than the blocks 32 having no such grooves. It is to be understood, however, that the illustrated grooves 45 are by way of example only and can be replaced by other depressions of any desired shape or arrangement. desired shape or arrangement. WHAT WE CLAIM IS:

1. A jaw plate structure for use in the opposed, coacting jaws of a jaw crusher, comprising a base of relatively ductile material having a crushing surface which is corrugated to provide alternating ridges and furrows with a preselected pitch (P), there being a series of recesses of generally rectangular shape in the crushing surface aligned along each ridge thereon, each recess having a width (W) ranging from 0.2 to 0.8 times the pitch (P) and a length (L) ranging from 0.2 to 3.00 times the pitch (P), each series of recesses to 0.50 times the pitch (P), each series of recesses having spacing gaps (S) therebetween ranging from 0.05 to 0.50 times the pitch (P), a plurality of blocks each formed or more wear-resistant material than the base and fitted in one of the respective recesses in the crushing surface of the base, each block having an exposed surface shaped to conform to the shape of each ridge of the crushing surface and having a portion projecting beyond both lateral edges of the base bounding the open end of each recess, the projecting portion of each block having a height (H) ranging from 0.17 to 1.0 times the pitch (P). and means for securing the blocks to the base.

as illustrated by the accompanying drawings.