Source: http://www.google.com/patents/US4871119?dq=5,598,374
Timestamp: 2014-12-18 05:15:32
Document Index: 460521330

Matched Legal Cases: ['art.\n3', 'art 12', 'arts 13', 'art 12', 'arts 13', 'art 13']

Patent US4871119 - Impact crushing machine - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAn impact crushing machine provided with easily repairable strikers fixedly arranged along the circumference of a rotor at regular angular intervals so as to extend radially of the rotor. A plurality of seats fixedly mounted respectively with striking chips formed of a durable hard material such as a...http://www.google.com/patents/US4871119?utm_source=gb-gplus-sharePatent US4871119 - Impact crushing machineAdvanced Patent SearchPublication numberUS4871119 APublication typeGrantApplication numberUS 07/164,181Publication dateOct 3, 1989Filing dateMar 4, 1988Priority dateMar 6, 1987Fee statusPaidAlso published asDE3807176A1Publication number07164181, 164181, US 4871119 A, US 4871119A, US-A-4871119, US4871119 A, US4871119AInventorsHiroyuki Murata, Takeshi Tanaka, Chouji Hino, Harunaga Kiuchi, Masahiro ChijiOriginal AssigneeKabushiki Kaisha Kobe Seiko ShoExport CitationBiBTeX, EndNote, RefManPatent Citations (8), Referenced by (23), Classifications (6), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetImpact crushing machineUS 4871119 AAbstract An impact crushing machine provided with easily repairable strikers fixedly arranged along the circumference of a rotor at regular angular intervals so as to extend radially of the rotor. A plurality of seats fixedly mounted respectively with striking chips formed of a durable hard material such as a hard metal are arranged in lines and rows on and detachably fixed to the radially outer end of the striker for individual replacement. When the striking chip is abraded to an unusable extent, the seat mounted with the worn striking chip and a seat fixedly mounted with an unworn striking chip can be interchanged for the further use of the striker, so that the frequency of replacing the heavy striker with a new one is reduced and the operating cost of the impact crushing machine is reduced.
What is claimed is: 1. An impact crushing machine, comprising:a casing; a rotor supported for rotation on a main shaft extended within said casing; a plurality of strikers fixed to the circumference of the rotor; an impact plate liner extending around the rotor at a predetermined distance from the rotor; a plurality of seats arranged axially in at least one row and radially of the rotor and which are removably fixed to each striker; a plurality of hard metal chips fixed, respectively, to said seats wherein said hard metal chips are removably attached to said seats, and at least a contact surface between the seat provided on the radially outer line and each hard metal chip joined to said seat is inclined toward the direction of rotation of said rotor at an angle of 3� to 25�. 2. An impact crushing machine according to claim 1, wherein a thickness dimension of said hard metal chips at a radially inner part is greater than that at a radially outer part.
3. An impact crushing machine, comprising:a casing; a rotor supported for rotation on a main shaft extending within said casing; a plurality of strikers fixed to the circumference of said rotor; an impact plate liner extending around said rotor at a predetermined distance from the rotor; a plurality of seats arranged axially in at least one row and radially of the rotor and which are removably fixed to each striker; a plurality of hard metal chips fixed to said seats wherein said seats are fastened to each striker so that an entire face of said hard metal chips can be used for crushing. 4. An impact crushing machine, comprising:a casing; a rotor mounted for rotation on a main shaft extended within said casing; a plurality of strikers fixedly attached to the circumference of the rotor, to crush and send flying rocklike pieces by respective extremities of said strikers; an impact plate liner extended around the rotor at a predetermined distance from the rotor, to crush and repulse rocklike pieces sent flying by the strikers; a plurality of seats, said seats being arranged axially of the rotor in a row on the extremity of each striker and removably fixed to the extremity of each striker; and a plurality of hard metal chips fixed, respectively, to each of said seats, wherein said hard metal chip is joined to said seat removably attached to the extremity of the body of said striker, and at least a contact surface between the seat provided on the radially outer line and said hard metal chip joined to said seat is inclined toward the direction of rotation of said rotor at an angle in the range of 3� to 25�. Description
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an impact crushing machine provided with strikers which are durable, sufficiently abrasion-resistant and can easily be replaced with new ones when worn out.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1(a) and 1(b), a striker 10, in a first embodiment, according to the present invention comprises a body 11 having a recessed part 12 having inlet parts 13, a plurality of seats 14, arranged in a row respectively fitting the recesses and fixed to the recessed part 12 of the body 11, and hard metal chips 15 respectively brazed to the seats 14. The seats 14 are detachably fixed to the body 11 respectively with bolts 17. A brazing sheet (i.e., a clad sheet formed by cladding both sides of a copper plate, respectively, with two layers of silver solder) is used for brazing the hard metal chip 15 to the seat 14. The hard metal chip 15 may be fixed to the seat 14 by welding, such as pressure welding by HIP, electron beam welding or laser welding, or by mechanical means. The inlet parts 13 are provided to prevent the seats 14 from being loosened by shocks and to prevent the action of a high centrifugal force on the bolts 17. The bottom surface of the seat 14 is engraved in a shape as shown in FIGS. 14(a), 14(b) or 14(c) so that the bottom surface and the inlet part 13 complement each other.
FIGS. 2(a) and 2(b) show modifications of the hard metal chip 15. In the modification shown in FIG. 2(a), the thickness of the hard metal chip 15b' is varied along the radial direction to reduce the quantity of the hard metal forming the hard metal chip, to extend the life of the striker and to use only one side of the hard metal chip so that the hard metal chip is economized. In such a tapered hard metal chip tapered toward the radially inner end thereof, the minimum thickness t is on the order of 3 mm and the inclination θ of the back surface to the front surface is in the range of 3� to 25�. Tensile stress exerted by the impact of a rocklike piece on the surface of the hard metal chip having a thickness of t can be analyzed by a finite element method and is expressed by
where σ is the tensile stress, k is a proportinal constant, and P is an impact applied to the hard metal chip by a rocklike piece. Therefore, the reduction of the minimum thickness t (FIG. 15) of the hard metal chip entails frequent cracking of hard metal chips. From such a point of view, various trial hard metal chips varying in the minimum thickness t in the range of 2 to 10 mm and in the inclination θ of the back surface in the range of 0� to 30� were subjected to cracking tests in which the circumferential speed of the rotor was 28 m/sec, the size of the rocklike pieces was in the range of 0 to 50 mm and crushing rate was 140 t/hr.
The results of the cracking test are shown in FIG. 15, in which black circles indicate hard metal chips which were cracked to an unusable degree, blank triangles indicate those which were partly chipped at the edges to a degree which will not interfere with the practical crushing operation of the impact crushing machine, and blank circles indicate those which were neither cracked nor chipped. As is obvious from FIG. 15, the hard metal chips are sufficiently durable when the inclination θ is in the range of 3� to 25� and the minimum thickness t is on the order of 3 mm. More explicitly, all the hard metal chips having the minimum thickness of 3 mm and the inclination θ in the range of 3 � to 25� were cracked somewhat on the working surfaces thereof. This is due to the reduction of the minimum thickness t to the lower limit of the desirable range. All the hard metal chips having the inclination θ of 25� and the minimum thickness in the range of 3 to 7 mm were chipped somewhat. In those hard metal chips, the angle φ between a tangent f and the joining surface is an acute angle and thereby stress is concentrated on the contact point between the upper contact surface 23 of the hard metal chip and the body of the striker to chip a portion of the hard metal chip in the vicinity of the contact point.
A large inclination θ is advantageous in preventing cracking and chipping when the minimum thickness t is sufficiently large, because the greater the inclination θ, the greater the thickness of the outer end of the hard metal chip. When the inclination θ was 3�, the hard metal chips respectively having a minimum thicknesses of 3 mm and 5 mm were chipped, while those having a minimum thickness of 7 mm or greater were not chipped. When the inclination θ was 5�, the hard metal chips having a minimum thickness t of 3 mm were chipped, while those having a minimum thickness t of 5 mm or above were not chipped.
Thus, it was found that hard metal chips having a minimum thickness t of 5 mm or above and the inclination θ in the range of 5� to 20� will not be chipped at all. The material forming the trial hard metal chips was K20 (JIS B 4104).
As is obvious from FIG. 17, an inclination greater than an angle of 3� limited damages in the hard metal chips to an acceptable extent, and a minimum thickness t of 5 mm or above is sufficient when the inclination is an angle of 3� or above. However, when the minimum thickness is 3 mm, all the hard metal chips were chipped somewhat even if the inclination θ was greater than an angle of 3�, and all the hard metal chips were damaged to an unusable extent when the minimum thickness was 2 mm. Although the hard metal chips were neither cracked not chipped when the inclination θ was greater than an angle of 25�, rocks sent flying by the crushing surface 20c impinged against the backside of the body of the adjacent striker abrading the backside of the body when the inclination θ was greater than the angle of 25�. Therefore, it is not desirable to form the contact surface of the seat with an inclination greater than an angle of 25�.
In a striker in a seventh embodiment according to the present invention shown in FIG. 10, a plurality of hard metal chips 21l are arranged in a single axial line. Each hard metal chip 21l and each seat 20l are square in shape. Therefore, when one edge of the hard metal chip 21l is abraded to a maximum extent, the seat 20l can be turned through an angle of 90� to use a new edge of the hard metal chip 21l. The life of the striker in the seventh embodiment was 10 times that of the conventional striker formed of high chromium cast iron. As mentioned above, the seat and the body of the striker are abraded in shapes indicated by broken lines 25b, 25c and 25d in FIGS. 4(a), 4(b) and 4(c). It was found that the angles respectively between the abraded surface indicated by the broken line 25b and the top 24b, between the abraded surface indicated by the broken line 25c and the top 24c, and between the abraded surface indicated by the broken line 25d and the top 24d is approximately an angle of 15�. That is, these broken lines correspond to a falling curve of rocklike pieces. FIG. 18 shows the results of experimental examination of the falling mode of rocklike pieces.
FIG. 18 is a graph showing the variation of the depth of abrasion at the top of the striker with the quantity of crushed rocklike pieces, hence, the duration of crushing operation. As is obvious from FIG. 18, the depth of abrasion increases to a value on the order of 27 mm and the angle θ between the top and the abraded surface increases to an angle of 15� and the depth of abrasion and the angle θ remain constant thereafter. Therefore, when the fastening members such as bolts are provided on radially inner side relative to the broken line indicating the limit of abrasion, the fastening member will not be abraded. Furthermore, a bolt fastening the axially outermost seat 14 to the body of the striker is positioned axially inside relative to a plane inclined at an angle of 15� to the surface of a side casing liner 9 and passing the axially outer end 20 of the contact surface 19 between the hard metal chip 15 and the seat 14 as shown in FIG. 19.
FIG. 20 is a graph showing the variation of the measured depth h of abrasion of the side surface of the striker and that of the measured angle θ between the abraded surface 21 and the side surface of the striker with the quantity of crushed rocklike pieces, hence, with the duration of crushing operation when the rotor 5 was rotated at a circumferential speed of 28 m/sec for experimental crushing operation. As is obvious from FIG. 20, the depth h increased to a value on the order of 25 mm and the angle θ increased to an angle of 15� and remained constant thereafter regardless of the material of the body of the striker. Accordingly, the bolt will not be abraded when the same is provided at a position axially inside the abraded surface 21 inclined at an angle of 15� to the original side surface of the striker.
The strikers shown in FIGS. 11(a), 11(b) and 11(c) are designed on the basis of such experimental results. A top surface 24m (24n, 24p) including those of a seat 20m (20n, 20p) and the body 22m (22n, 22p) of the striker (strikers) is inclined radially inward at an angle of 15� to a tangent 32m (32n, 32p) to a hard metal chip 21m (21n, 21p) at the upper end of the same. Accordingly, the seat 20m (20n, 20p) and the body 22m (22n, 22p) are not subject to abrasion, and hence the head of a bolt 23m (23n, 23p) fastening the seat 20m (20n, 20p) to the body 22m (22n, 22p) is not abraded. Furthermore, since a portion of the seat 20m (20n, 20p) near the contact surface between the hard metal chip (21m (21n, 21p) and the seat 20m (20n, 20p) is not abraded in a groove, the hard metal chip is hardly chipped even if the upper edge of the hard metal chip is abraded with a sharp edge, which further reduces the consumption of the hard metal chips.
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