Patent Grant
8668158
This application claims priority under 35 U.S.C. §119 to Swedish Patent Application No. 1050377-9, filed on Apr. 16, 2010, which is incorporated by reference herein in its entirety.
The present invention relates generally to a horizontal shaft impact crusher including a crusher housing having an inlet for material to be crushed and an outlet for material that has been crushed, an impeller mounted on a horizontal shaft in the crusher housing and operative for rotating around a horizontal axis, a curtain against which material accelerated by the impeller may be crushed, and an adjustment device for adjusting the position of the curtain relative to the impeller.
Horizontal shaft impact crushers are utilized in many applications for crushing hard material, such as pieces of rock, ore, etc. A horizontal shaft impact crusher has an impeller that is made to rotate around a horizontal axis. Pieces of rock are fed towards the impeller and are struck by beater elements mounted on the impeller. The pieces of rock are disintegrated by being struck by the beater elements, and are accelerated and thrown against breaker plates, often referred to as curtains, against which further disintegration occurs. The action of the impeller thus causes the material fed to the horizontal shaft impact crusher to move freely in a crushing chamber and to be crushed upon impact against the beater elements, against the curtains, and against other pieces of material moving around at high speed in the crushing chamber.
Adjustment of the position of the curtain may be made to compensate for both curtain wear and beater element wear. Furthermore, adjustment of the position of the curtain may be made to adjust the size of the crushed material.
U.S. Pat. No. 4,017,035 discloses a horizontal shaft impact crusher which is provided with supporting hydraulic cylinders for adjusting and maintaining the position of the curtain. However, the design of the crusher described in U.S. Pat. No. 4,017,035 is considered to be complex and may be costly to manufacture and/or operate.
The present invention aims at obviating the above-mentioned disadvantages of previously known horizontal shaft impact crushers and at providing an improved crusher. Therefore, a primary object of the invention is to provide a simple and robust horizontal shaft impact crusher that allows for simple adjustment of the position of the curtain relative to the impeller, thereby controlling the wear of the curtain and impeller beater elements while minimizing cost of manufacture and operation of the crusher.
In an embodiment, the invention provides a horizontal shaft impact crusher, including a crusher housing that has an inlet for material to be crushed and an outlet for material that has been crushed. An impeller is mounted on a horizontal shaft in the crusher housing and is operative for rotating around a horizontal axis. A curtain is provided against which material accelerated by the impeller may be crushed. An adjustment device is included for adjusting the position of the curtain relative to the impeller. The adjustment device is slidably connected to at least two guide rails provided with the crusher housing. A retaining device is arranged to hold, with a predetermined holding force, the adjustment device in a crusher operation position relative to the guide rails. The adjustment device is movable along the guide rails from the crusher operation position and away from the impeller in response to an excessive force being transferred from the curtain to the adjustment device and exceeding the predetermined holding force.
An advantage of this embodiment of the horizontal shaft impact crusher is that the adjustment of the curtains may be carried out in a simple and mechanically stable manner since the adjustment device may be arranged to slide easily along the guide rails when not retained by the retaining device. Furthermore, a robust and reliable mounting of the crusher curtains in different positions may be achieved. The adjustment device can still slide, in a predictable manner, when exposed to excessive forces also when the adjustment device is retained by the retaining device. When retained, the adjustment device is slidable in response to excessive forces caused by, for example, non crushable objects. Hence, a reliable overload protection is achieved.
In response to a force sufficiently large to overcome the holding force of the retaining device the adjustment device can thus slide although retained by the retaining device. In such a situation, which may be the result of a non crushable object being inadvertently introduced to the crusher, the adjustment device thus slides against the holding force of the retaining device.
A further advantage of this embodiment of the crusher is that the manufacturing costs thereof may be reduced since the adjustment device may be retained by a mechanical retaining device, such as a bolt, and thus no hydraulic device is needed to retain the curtains in a desired position.
According to one embodiment the adjustment device is retained by a hydraulic or a pneumatic device in order to enable adjustment of the curtain in a very simple manner by, e.g., a small hydraulic cylinder. Such a hydraulic or pneumatic device only needs to be capable to generate a certain friction force between the adjustment device and the guide rods and may thus be small compared to the supporting hydraulic cylinders used in U.S. Pat. No. 4,017,035.
In another embodiment, each of the guide rails has a receiving portion adapted to at least partly enclose a connection portion of the adjustment device in order to improve the robustness and stability of the device when retained to the guide rails and the guidance stability when adjustment of the curtain is carried out. Furthermore, improved control as regards the holding force of the retaining device is achieved.
The profile of the connection portion may be V-shaped and arranged with its sharp end facing the receiving portion of the respective guide rail.
In another embodiment, the adjustment device further includes at least one resilient member arranged to dampen forces exerted on the curtain. The at least one resilient member can include a spring.
In one embodiment, the adjustment device is provided with a hydraulic device which is operative for adjusting the distance between a cross beam to which the curtain is connected and the housing of the crusher. This has the advantage that the curtain can be positioned in an easy and safe manner, thereby enabling production to be maintained quickly and easily after, e.g., an overload situation.
In another embodiment, the adjustment device further includes a compression plate which supports the at least one resilient member and is connected to the curtain, the compression plate being retractable away from the impeller by the hydraulic device.
In yet another embodiment, the adjustment device is further provided with a safety mechanism for preventing the curtain to come into contact with the beater elements of the impeller.
According to one embodiment a hydraulic device is operative for retracting the curtain from the impeller against the force of at least one resilient member with the adjustment device still in the crusher operation position, such that blockages can be cleared from the crusher without having to release the adjustment device. An advantage of this embodiment is that blockages that do not cause forces exceeding the predetermined holding force can be cleared from the crusher without having to dismount any parts, such as the adjustment device.
The adjustment device can include a horizontal cross beam on which the at least one connection portion is arranged, in order to achieve a very robust design.
In an embodiment, the at least one connection portion is arranged in alignment with a longitudinal center plane of a cross beam, in order to further improve the stability of the adjustment device.
According to one embodiment the adjustment device is provided with a cross beam and two V-shaped connection portions, e.g., in the form of V-shaped guide blocks, both of which are aligned to a longitudinal center plane of the cross beam. This embodiment has the advantage that the stability and/or robustness of the adjustment device may be even further improved.
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention.
a is a plan view and illustrates, schematically, a guide block received in a guide rail of the crusher shown in
b is a section view and illustrates the guide block and guide rail shown
a-c are sections of the adjustment device shown in
Material to be crushed is fed to an inlet 8 for material to be crushed. The crushed material leaves the crusher 1 via an outlet 10 for material that has been crushed.
The housing 2 is provided with a plurality of wear protection plates 12 that are operative for protecting the walls of the housing 2 from abrasion and from impact by the material to be crushed. Furthermore, the housing 2 includes a bearing 14 for the horizontal shaft 6. A lower feed plate 16 and an upper feed plate 18 are arranged at the inlet 8. The feed plates 16, 18 are operative for providing the material fed to the crusher 1 with a suitable direction with respect to the impeller 4.
The crusher 1 includes a first curtain 28, and a second curtain 30. Each curtain 28, includes at least one wear plate 32 against which material may be crushed.
A first end 34 of the first curtain 28 has been mounted by a horizontal first pivot shaft 36 extending through an opening 38 formed in the first curtain 28 at the first end 34. The first pivot shaft 36 extends further through openings in the housing 2 to suspend the first end 34 in the housing 2. A second end 40 of the first curtain 28 is connected to a first adjustment device 42 including two parallel adjustment bars 44, of which only one bar 44 is visible in
A first end 52 of the second curtain 30 has been mounted by a horizontal second pivot shaft 54 extending through an opening 56 formed in the second curtain 30 at the first end 52. The second pivot shaft 54 extends further through openings in the housing 2 to suspend the first end 52 in the housing 2. A second end 58 of the second curtain 30 is connected to a second adjustment device 60 including two parallel adjustment bars 62, of which only one bar 62 is visible in
The impeller 4 is provided with four beater elements 70, each such beater element 70 having a “banana” shape, as seen in cross-section. Each beater element 70 has a central portion 72 which is operative for co-operating with a mounting block 74 being operative for pressing the back of the beater element 70 towards the impeller 4 to keep the beater element 70 in position. An arrow R indicates the direction of rotation of the impeller 4. A leading edge 76 of the beater element 70 extends in the direction of rotation R, such that a scoop-area 78 is formed between the central portion 72 and the leading edge 76. The beater element 70 is symmetric around its central portion 72, such that once the leading edge 76 has been worn out, the beater element 70 can be turned and mounted with its second leading edge 80 operative for crushing material. The area formed between the impeller 4 and the first and second curtains 28, 30 can be called a crushing chamber 82 of the crusher 1.
In operation, material to be crushed is fed to the inlet 8. The material will first reach the first curtain 28, being located upstream of the second curtain 30 as seen with respect to the direction of travel of the material. The feed plates 16, 18 direct the material towards the impeller 4 rotating at, typically, 400-850 rpm. When the material is hit by the beater elements 70 it will be crushed and accelerated against the wear plates 32 of the first curtain 28 where further crushing occurs. The material will bounce back from the first curtain 28 and will be crushed further against material travelling in the opposite direction and, again, against the beater elements 70. When the material has been crushed to a sufficiently small size it will move further down the crusher chamber 82, and will be accelerated, by the beater elements 70, towards the wear plates 32 of the second curtain 30, being located downstream of the first curtain 28. Hence, the material will move freely around in the crushing chamber 82, and will be crushed against the beater elements 70, against the wear plates 32 of the curtains 28, 30, and against other pieces of material circling around, at a high velocity, in the crusher 1. Arrows F indicate the path of the material through the crusher 1.
By adjusting the longitudinal position of the adjustment bar 44 in relation to the housing 2, the first curtain 28 may be pivoted around the first pivot shaft 36 until an optimum distance between the second end 40 and the impeller 4 has been obtained, with respect to the properties, as regards, e.g., size and hardness, of the material to crushed. Hence, the adjustability of the distance between the first curtain 28 and the impeller 4 is largest at that location, i.e., at the second end 40 of the first curtain 28, where the distance between the first curtain 28 and the impeller 4 is normally the smallest. In a similar manner the second adjustment device 60 may be utilized for making the second curtain 30 pivot around the second pivot shaft 54 until a suitable distance between the impeller 4 and the second end 58 of the second curtain 30 has been obtained.
As illustrated in
The guide blocks 86 can slide along the guide rails 90. Adjustment of the cross beam 84, and thereby of the first curtain 28 which is connected to the cross beam 84 via the bars 44, to a correct position in relation to the impeller 4 with respect to the properties of the material to be crushed may be carried out by adjusting the position of cross beam 84 by having the guide blocks 86 slide relative to the guide rails 90.
As illustrated in
Each guide rail 90 is provided with a longitudinal slot 94, as is best illustrated in
As mentioned above each of the guide rails 90 has a groove 91 with a shape that is complementary to the corresponding V-shaped guide block 86. The V-shaped guide block 86 in combination with the V-shaped groove 91 of the guide rail 90 provides for lateral guidance of the cross beam 84 and helps to prevent the cross beam 84 from twisting during crusher 1 operation and adjustment.
After adjusting the position of the cross beam 84 to a desired position, i.e., a position at which the first curtain 28 is located at a desired distance from the impeller 4 with respect to the size of the material that is to be crushed, the bolts 92 are tightened to such extent, for example to a predetermined torque, that a predetermined holding force in the form of the friction force between the V-shaped guide blocks 86 and the grooves 91 of the guide rails 90 is generated. This predetermined holding force is large enough to prevent relative displacement between the cross beam 84 and the crusher housing 2 under normal crushing conditions. Hence, the bolts 92 are tightened to a specific tightening moment that provides the desired frictional force between the guide blocks 86 and the guide rails 90. The first curtain 28 is thus prevented from pivoting around the first pivot shaft 36 under normal crushing conditions. If a bulky and non crushable object is introduced into the crusher 1 the forces exerted on the first curtain 28, to which the adjustment device 42 is connected, is raised significantly. When such forces, denoted excessive forces, exceed the predetermined holding force in the form of the friction force between the V-shaped guide blocks 86 and the grooves 91 of the guide rails 90 the guide blocks 86 slide along the guide rails 90, in a direction away from the housing 2 and away from the impeller 4, causing the first curtain 28 to pivot around the first pivot shaft 36, thereby increasing the distance between the impeller 4 and the first curtain 28 such that the non-crushable object can pass through the crusher 1. In this manner damage to parts of the crusher 1 caused by non-crushable objects introduced to the crusher 1 can be avoided.
The hydraulic cylinder 95 includes a piston 95a which abuts, during an adjustment procedure, the roof of the housing 2, as illustrated in
The first curtain 28, which is connected to the cross beam 84 of the adjustment device 42, may be repositioned in order to change crusher 1 settings by first loosening the bolts 92 and then displacing the cross beam 84 along the guide rails 90 with the help of the hydraulic cylinder 95.
The adjustment device 42 further includes resilient members, in the form of springs 96, as is best illustrated in
The adjustment device 42 is further provided with a mechanical safety device 98, illustrated in
The retaining bolts 92 are arranged to hold the adjustment device 42 in a desired crusher 1 operation position as long as the forces applied to the guide blocks 86 do not exceed the predetermined holding force. However, the adjustment device 42 is slidable in response to an excessive force that overcomes the predetermined holding force generated by the retaining bolts 92. The guide blocks 86 may then slide against the friction force generated between the guide blocks 86 and the grooves 91 of the guide rails 90 by the tightened retaining bolts 92 and the respective clamping plates 100.
When material is crushed in the crusher 1, forces are applied to the adjustment device 42 via the first curtain 28. As long as the crusher 1 is fed with material of the type the crusher 1 is designed to crush, the predetermined holding force is not exceeded which means relative displacement of the adjustment device 42 is prevented. However, it may happen that a non-crushable object of a certain size is introduced into the crusher 1. Such a non crushable object will exert excessive forces to the first curtain 28 and the adjustment device 42. When a force exceeding the predetermined holding force is exerted on the adjustment device 42, the predetermined holding force, i.e., the friction force between the guide blocks 86 and the grooves 91 generated by the retaining bolts 92, is no longer enough to prevent the adjustment device 42 from sliding along the guide rails 90 away from the housing 2 and away from the impeller 4, such that the first curtain 28 is moved away from the impeller 4. Hence, in an overload situation, i.e., when the predetermined holding force is exceeded, displacement of the first curtain 28 is enabled, hence avoiding damage to the first curtain 28 and the adjustment device 42.
As long as forces acting on the adjustment device 42 do not exceed the predetermined value, the retaining bolts 92 prevent relative displacement of the adjustment device 42. The first curtain 28 will thus maintain the position to which it is adjusted as long as no overload situation occurs. Since the first curtain 28 is held in position by a mechanical fastening device, in the form of tightened bolts 92, no hydraulic pressure is needed to secure the first curtain 28 position. A reliable and simple overload protection is thus achieved.
The guide blocks 86 together form a slidable member which prevents relative displacement of the adjustment device 42 under normal conditions and which allows relative displacement in case of an overload situation.
a, 5b and 5c further illustrate a crossbeam compression plate 106. The crossbeam compression plate 106 supports lower spring seats 106a. In the situation illustrated in
Hereinbefore it has been described that the crusher 1 is provided with a first curtain 28, and a second curtain 30 located downstream of the first curtain 28. It will be appreciated that a crusher 1 may also be provided with further curtains, such as a third curtain located downstream of the second curtain 30. An adjustment device 42 of the type that has been described in detail hereinbefore can be arranged for one, two, or all of the curtains 28, 30 of a crusher 1. Hence, the adjustment device 60 being operative for controlling the position of the second curtain 30 could be similar to the adjustment device 42.
Hereinbefore it has been described that the second adjustment device 60 operative for adjusting the position of the second curtain 30 may be of a similar design as the first adjustment device 42 operative for adjusting the position of the first curtain 28. It will be appreciated that the second adjustment device 60 may, optionally, be arranged without a safety device 98, since the second curtain 30, hanging, as illustrated in
In the described embodiment the adjustment device 42 includes a hydraulic cylinder 95 for positioning the first curtain 28 into a correct position. It is, however, also possible to make the adjustment device 42 entirely mechanical, which may reduce investment and maintenance costs.
Hereinbefore it has been described that the V-shaped guide blocks 86 are mounted on the adjustment device 42 and co-operate with V-shaped grooves 91 on the respective guide rails 90. It will be appreciated that the opposite arrangement is also possible, i.e., that the adjustment device 42 could, as alternative, be provided with V-shaped grooves co-operating with guide rails being generally V-shaped blocks. Furthermore, other shapes are also possible, including guide blocks 86 having a cross-section having the shape of a half-circle or some other suitable shape. Preferably, the shape is such that it provides both a predictable friction and a guidance in the horizontal direction.
In the described embodiment retaining bolts 92 are arranged to hold the adjustment device 42 in a desired crusher 1 operation position. It is realized that other devices, including a small hydraulic cylinder, capable of generating the required friction force between the guide block 86 and the guide rail 90, may be used instead of bolts 92. According to one embodiment the retaining device includes two small hydraulic cylinders.
Hereinbefore it has been described that the adjustment device 42 includes a compression plate 106 supporting spring seats 106a of each of the springs 96. In an alternative embodiment the first adjustment device 42 may include two compression plates 106, each of which support a respective spring seat. A number of hydraulic devices operative for moving each of the two compression plates may then be needed in order to provide a robust adjustment device 42.
In the described embodiment resilient members in the form of springs 96 are arranged to dampen forces exerted on the first curtain 28. Alternatively, such a resilient member may be formed from another component having resilient characteristics, such as, for instance, a component formed from an elastic material.
It is further realized that the adjustment device 42 may include a resilient member in the form of one single resilient member, such a single spring being, preferably, arranged on the cross beam 84 centrally between the two bars 44.
Hereinafter a crusher according to a second embodiment will be described with reference to
Hence, in this embodiment the horizontal shaft impact crusher includes a first and a second V-shaped connection portion, in the form of V-shaped guide blocks 86, fastened to a cross beam 84. The V-shaped guide blocks 86 are centrally arranged, i.e. arranged in alignment with a center plane LCP of the cross beam 84, as illustrated in
This embodiment has the advantage that the stability of the adjustment device 42 is further improved. A first curtain 28 position may be adjusted using the hydraulic cylinder 95 as described hereinbefore. By arranging the V-shaped guide blocks 86 adjacent to the center plane LCP of the cross beam 84, as illustrated in
The second embodiment also differs in that the bolts 88 securing the guide block 86 to the cross beam 84 are countersunk, as illustrated in
Furthermore, the second embodiment also differs in that the friction coating 93 includes two separate friction coating 93 elements 93a and 93b, as illustrated in
While the invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the invention, as defined in the appended claims and their equivalents thereof. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1050377 | Apr 2010 | SE | national |
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| Entry |
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| Notification of First Office Action (with English Translation) in Chinese patent application No. 201180019393.5 dated Dec. 4, 2013. |
| Notification of First Office Action (with English Translation) in Chinese patent application No. 201180019400.1 dated Dec. 12, 2013. |
| Number | Date | Country | |
|---|---|---|---|
| 20110253822 A1 | Oct 2011 | US |
