The invention relates to a jaw crusher having a stationary crusher jaw and having a movable crusher jaw, between which a crushing chamber and a crushing gap are formed, wherein the movable crusher jaw can be driven by a crusher drive to generate a crushing motion, wherein an overload protection mechanism is assigned to one of the crusher jaws, preferably to the movable crusher jaw, wherein the overload protection mechanism comprises a control unit, which, in the event of an overload, causes the crusher jaws to move relative to one another in such a way that the crushing gap is enlarged.
Jaw crushers of the type mentioned above are used for crushing rock material, such as natural stone, concrete, bricks or recycled material. The material to be crushed is fed to a feed unit of the material crusher plant, for instance in the form of a hopper, and fed to the crusher unit via transport devices. In a jaw crusher, two crusher jaws arranged at an angle to each other form a wedge-shaped shaft into which the material to be crushed is introduced. While one crusher jaw is stationary, the opposite crusher jaw can be moved by means of an eccentric and is supported by a pressure plate on a control unit. The latter is articulated in relation to the swingarm holding the movable crusher jaw and the actuator unit. This results in an elliptical motion of the movable crusher jaw, which crushes the material to be crushed and guides it downwards in the shaft into a crushing gap. A control unit can be used to adjust the gap width of the crushing gap.
The crusher is exposed to high mechanical loads during the crushing process. These result from the feed size, the grain distribution and the crush resistance of the fed material and from the desired crushing ratio and the filling level of the material to be crushed in the crushing chamber of the crusher. Incorrect operation of the material crusher plant, in particular if a non-crushable element, e.g. a steel element, enters the crushing chamber, can result in an overload of the crusher. This can damage or wear out components of the crusher prematurely.
In the event of an overload, the pressure plate can also serve as a predetermined breaking point. If a non-breakable object in the crushing chamber blocks the crusher jaws, the forces acting on the movable crusher jaw increase. These forces are transferred into the pressure plate. If the forces are excessive, the pressure plate buckles. This causes the movable crusher jaw to move out of the way and the crushing gap to increase. In this way the unbreakable object can then fall out of the crushing chamber. This reliably prevents damage to important system components of the jaw crusher. Clearly this procedure can only be used sensibly if the frequency of foreign elements entering the crushing chamber is very low because the pressure plate is damaged every time. Therefore, ways to avoid damage to the pressure plate based on the state of the art were sought. For this reason, EP 2 662 142 B1 proposes a jaw crusher, in which the moving crusher jaw is again supported by a pressure plate. The pressure plate itself is supported by a hydraulic cylinder on its side facing away from the movable crusher jaw. A high-pressure valve is assigned to the hydraulic cylinder. If an overload situation now occurs, the valve opens and the hydraulic cylinder is triggered. Then the movable crusher jaw can move out of the way, which increases the crushing gap. The disadvantage of this design is that the hydraulic cylinder no longer provides rigid support for the moving crusher jaw during the crushing process. The hydraulic cylinder brings too much elasticity into the system affecting the crushing result.
The invention addresses the problem of providing a jaw crusher of the type mentioned above, which reliably withstands high loads in continuous operation.
This problem is solved by an actuator unit being driven by means of the kinetic energy of a driven component of the jaw crusher, in particular of at least one flywheel of a crusher drive, of the movable crusher jaw and/or of the crusher drive (30) driving the movable crusher jaw, and by at least one actuator (80) being acted upon by the actuator unit (100) using a transfer medium to effect the gap adjustment.
I.e., the kinetic energy of a driven component of the jaw crusher, in particular the flywheel(s) or the crusher drive driving the flywheels and the movable crusher jaw, or the movable crusher jaw itself, is used to drive the actuator unit. There, the power is sufficiently high to be used to operate the overload protection. Accordingly, the actuator unit is used to control one or several actuators, wherein the energy provided by the actuator unit is transmitted to the actuator. In particular, an actuator can be used, for instance, to move an actuator unit, which supports the crusher jaw during crushing operation to permit the movable crusher jaw to be moved. According to the invention, a transfer medium is used to transmit from the actuator unit to the actuator, which transfer medium can be an oil, in particular a hydraulic oil.
According to a preferred variant of invention, provision may be made that the movable crusher jaw is supported relative to the crusher frame on a control element of the control unit, wherein the control element can be adjusted relative to the movable crusher jaw in order to be able to effect an adjustment of the crushing gap, and that the actuator acts on the control element to adjust the latter in case of overload.
The control unit can be used, for instance, to adjust the movable crusher jaw for normal crushing operation. Depending on the desired grain size, the crusher jaw is set to achieve a defined crushing gap. The crusher jaw is now supported by a control element of the control unit on the crusher frame, in particular on an adjustment wedge. In this way, a fixed allocation of the moving crusher jaw to the control unit is established. This fixed allocation provides for a defined and mechanically stable support. If a non-crushable object enters the crushing chamber during crushing operation, the control element, in particular the adjusting wedge, can be adjusted preferably transverse to the direction of motion of the movable crusher jaw. The movable crusher jaw moves out of the way. The crushing gap is enlarged.
It may be particularly preferably provided that the control unit has two control elements designed as wedge elements, which are supported in a sliding manner against each other at their wedge surfaces, that one actuator each is assigned to one or both control elements, and that the actuator unit can adjust one or both actuators. This wedge adjustment can be used to set the gap in a defined manner for the crushing process, with the aid of the actuators if applicable. If an overload situation now occurs, one or both actuators are used to effect the motion of the wedge elements. If both wedge elements are adjusted, a relatively large adjustment distance can be covered within a short time to effectively protect the crusher from an overload situation. Of course, based on a suitable design, it may also be sufficient to equip only one wedge element with an actuator and to control it using the actuation element.
In a further preferred variant of the invention, a pressure element, preferably a pressure plate, is used to support the movable crusher jaw with respect to the control unit, a tensioning cylinder holds the pressure element to the control unit using preload and in the event of an overload adjustment of the movable crusher jaw, effected by the actuator unit, the tensioning cylinder is also re-tensioned by the actuator unit. The pressure element is used as a transmission element to guide the motion of the movable crusher jaw in a defined way. The control unit supports the pressure plate. The control unit can be used to adjust the crushing gap in a defined way. If then the control unit or an element assigned to the control unit is displaced by the actuator unit in the event of an overload situation, the pressure plate has to be reliably held in position. This is guaranteed by the tensioning cylinder. As the actuator unit also acts on the tensioning cylinder, the functionality of the actuator unit can be extended. The force generated by the kinetic energy of the crusher drive and the moving crusher jaw can be used to adjust the tensioning cylinder.
In a particularly preferred variant of the invention a load sensor is used to detect an overload situation and a connected controller, and the controller activates the actuator unit when this overload signal is detected. The particular advantage of this system is that it not only reacts passively to an overload case, but that the actuator unit can be actively activated and controlled to counteract an overload case. A force transducer can be used as a load sensor, for instance, which directly or indirectly determines the force in a component of the jaw crusher. For instance, a part of the machine chassis, in particular the crusher frame, on which one of the two crusher jaws, preferably the stationary crusher jaw, is supported, can be measured. In particular, an extensometer can be used, which records the strain in the stressed component. Inferences from this elongation can be applied to the load behavior of the component.
A particularly preferred variant of invention is characterized in that the actuator unit is a fluid pump, preferably a hydraulic oil pump. The fluid, preferably hydraulic oil, can be effectively used as a transfer medium between the actuation element and the actuator and/or the tensioning cylinder. The high forces can be reliably transmitted in this way.
A possible embodiment of the invention is such, that the movable crusher jaw accommodates a drive shaft of the crusher drive for rotation, in that the drive shaft has a deflector element, in particular an eccentric or a cam disk, and in that an actuation element of the actuator unit interacts with the deflector element to drive the actuator unit. In this way, the energy from the crusher drive can be introduced into the actuation element of the actuator unit with little technical effort. In particular, provision may also be made that the actuation element rotatably receives a rolling element at a head, and that the running surface of the rolling element runs on the deflector element, in particular the cam disk. The rolling element can roll on the deflector element, in particular the cam disk, resulting in little wear and precise guidance.
A simple design is obtained for the actuator unit if provision is made that the actuator unit accommodates the actuation element adjustably in a housing, that the actuation element has at least one piston or is at least connected to such a piston, that the piston(s) is/are adjustable in one or more pump chambers, and that at least one pump chamber can be brought into fluid-conveying connection with the actuator and/or the tensioning cylinder.
A particularly preferred embodiment of the invention provides that the actuation element can be blocked, preferably hydraulically blocked, in a waiting position in the housing against the preload of a spring. During normal operation of the crusher, i.e. when there is no overload situation, the actuation element is kept in the waiting position. If the actuator unit is then activated in the event of an overload, the blockade of the actuation element can be lifted and the actuation element, supported by the spring, can be quickly brought into its functional position. In this way, the functionality of the system and its operational readiness are quickly established. Consequently, the system can react quickly to an overload. For this purpose, provision may also be made, additionally or alternatively, that a pressure accumulator is used which, when activated, forces a pressurized fluid into a first pump chamber of the actuator unit and in this way moves the actuation element from a waiting position or a pump end position to an extended activation position or supports this motion.
According to a particularly preferred embodiment variant of the invention, provision may be made that during the crushing operation the lower part of the movable crusher jaw makes a partial motion towards the stationary crusher jaw (closing motion) and a further partial motion away from the stationary crusher jaw (opening motion), and that the actuator unit uses the transfer medium to act on at least one actuator to effect the gap adjustment preferably synchronously with this motion, in particular preferably when the movable crusher jaw moves towards the stationary crusher jaw or when it moves away from the latter. The gap adjustment can therefore either counteract the partial closing motion reducing the resulting closing motion or support the partial opening motion increasing the opening motion.
Of course, the gap can also be adjusted when the crusher jaws are in an intermediate partial motion.
The invention makes use of the fact that when the movable crusher jaw moves away from the stationary crusher jaw (opening motion), a relief situation sets in.
Accordingly, the force on the support of the moving crusher jaw is reduced during this motion sequence, resulting in the force required for the gap adjustment being lower.
The invention is explained in greater detail below based on an exemplary embodiment shown in the drawings. In the Figures:
The material flow not screened out on the first screen deck 12.1 is fed into the crusher unit 20. The crusher unit 20 has a stationary crusher jaw 21 and a movable crusher jaw 22. A crushing chamber 23 is formed between the two crusher jaws 21, 22. At their lower ends, the two crusher jaws 21, 22 define a crushing gap 24. The two crusher jaws 21, 22 thus form a crushing chamber 23 converging towards the crushing gap 24. The stationary crusher jaw 21 is firmly mounted to the crusher frame 17. An eccentric drive 30 drives the movable crusher jaw 22. The crusher drive 30 has a drive shaft 31, on which a flywheel 30.1 is mounted for co-rotation. This will be explained in more detail below.
As
Finally,
The control unit 60 is used to adjust the crushing gap 24 between the two crusher jaws 21, 22. The control unit 60 may also be referred to as an adjustable support 60 configured to provide relative movement between the crusher jaws to adjust the crushing gap.
A tensioning cylinder 40 is provided in order to be able to maintain a defined allocation of the pressure plate 50 to the control unit 60 on the one hand and to the movable crusher jaw 22 on the other hand during the crushing process. The tensioning cylinder 40 has a piston rod 41, which bears a fastening element 42 at one end. The fastening element 42 is pivotably attached to the movable crusher jaw 22. The piston rod 41 is connected to a piston 45. The piston 45 can be linearly adjusted in the tensioning cylinder 40. A beam 44 bears the housing of tensioning cylinder 40. The beam 44 is supported by at least one, preferably two, compression springs 43 on a component of the crusher frame 17. A spring preload is applied accordingly. The spring preload causes a tension, which pulls the housing of the tensioning cylinder 40 and with the latter the piston 45 and the piston rod 41. In this way a tensioning force is applied to the movable crusher jaw 22, which tensioning force is transferred to the pressure plate 50. Accordingly, the pressure plate 50 is held in a clamped and preloaded manner between the movable crusher jaw 22 and the control unit 60.
As
According to a preferred invention variant, the actuators 80 act bidirectionally. They are used to allow the adjustment of the crushing gap 24 during normal crushing operation. Accordingly, they can be controlled via a controller, for instance. Because both actuators 80 are permanently coupled to the control elements 60.1, 60.2, the control elements 60.1, 60.2 can be moved linearly with the actuators 80. The gap width of the crushing gap 24 is determined depending on the control position of the control elements 60.1, 60.2. The tensioning cylinder 40 follows the adjustment motion, i.e. it is guaranteed that the pressure plate 50 is always held securely between the two pressure plate bearings 51, 52.
While a small crushing gap 24 is set in
As
As the illustration in
The actuation element 110 can be linearly adjusted in the housing 100.1. The actuation element 110 has a first piston 110.1 and a second piston 110.2. Embodiments, in which only one piston 110.1 is used, are also conceivable. The first piston 110.1 has a relatively smaller diameter than the second piston 110.2.
A connection piece 110.3 is connected to the second piston 110.1. The connection piece 110.3 is used to guide the actuation element 110 out of the housing 100.1, the connection piece 110.3 bears a head 120. A rolling element 130 is connected to the head 120 for rotation. The rolling element 130 can have the shape of a wheel, as shown here. The rolling element 130 has an outer circumferential running surface 131. The rolling element 130 may also be referred to as a roller 130.
As the drawings show, the actuation element 110 is supported in the housing 100.1 against the preload of a spring 140. The spring 140 acts on the actuation element 110 preferably in the area of one of the pistons 110.1, 110.2 and can be accommodated in a space-saving manner in one of the pump chambers, preferably in the first pump chamber 102.
The actuator unit 100 is spatially assigned to the deflector element 33 (see
If an overload occurs, the operating position as shown in
As mentioned above, it is advantageous if not only one actuator 80, but both actuators 80 are adjusted simultaneously. In this way, the crushing gap 24 can be enlarged within a very short time. In this case, both actuators 80 are connected to the first pump chamber 102.
As a result of an adjustment of the two actuators 80, the two control elements 60.1 and 60.2 are displaced relative to each other. Consequently, the movable crusher jaw 22 can move out of the way, increasing the crushing gap 24. The tensioning cylinder 40 is activated to prevent the pressure plate 50 from falling down, as mentioned above. The tensioning cylinder 40 pulls the movable crusher jaw 22 against the pressure plate 50 to keep the latter always tensioned.
In particular, it may be preferable to have the actuator(s) 80 of the actuator unit 100 pressurized two or more times within one overload cycle to open the crushing gap 24. Then the actuator unit can be designed having a relatively manageable installed size. For instance, it may be intended that the actuation element 110 of the actuator unit 100 described above performs two or more pump strokes. The actuator 80 and/or the tensioning cylinder 40 is/are in such a case not moved along its/their entire length of travel per pump stroke, but only along a partial length of travel. After the deflector element 33 is attached to the drive shaft 31, the pump strokes can be performed in short succession, one after the other, enabling the crushing gap 24 to be opened quickly.
It is also conceivable that the invention could be designed in such a way that the deflector element 33 is designed such that two or more pump strokes can be achieved per revolution. Similarly, a configuration of the invention is conceivable in which two or more actuator units are used, all of which act on the actuators simultaneously or with a time delay.
The position of the deflector element 33 on the drive shaft 31 determines the point at which the pumping action of the actuator unit 100 is initiated. The deflector element 33, which operates the rolling element 130, is arranged at an angular offset to the eccentric, which is responsible for the eccentric motion of the movable crusher jaw 22. Because of the angular offset, the opening motion of the control unit 60 can be synchronized with the motion of the moving crusher jaw. Particularly preferably, the deflector element 33 is set in such a way that the opening motion of the crushing gap 24 by the control unit 60 begins shortly before the closing motion of the crushing gap 24, which is performed by the rotation of the drive unit of the crusher. This prevents uncrushable material from being further pressed in the crusher jaw and reduces the load on the crushing mechanism. However, any other adjustment of the deflector element 33 relative to the eccentric is also conceivable. In principle, it would also be possible to adjust the position of the deflector element 33 relative to the eccentric during operation.
If a pump stroke is performed from the position shown in
In
As
A pressure accumulator 150 is also provided. The pressure accumulator 150 is used to keep hydraulic oil pressurized. In this exemplary embodiment, a housing, in which a piston 152 is preloaded against a spring 151, can be used to form the pressure accumulator 150. The housing is used to hold hydraulic oil, which is preloaded via the piston 152 and the spring 151. The spring chamber can be atmospherically balanced or have a gas pressure.
As
If now an overload occurs, the situation shown in
When the deflector element 33 meets the rolling element 130, the pumping motion starts, which pushes the actuation element 110 back from its extended position as shown in
Firstly, a pump pressure is generated in the pump chamber 103. The fluid port 100.3 is used to connect the pump chamber 103 to the chamber 40.1 of the tensioning cylinder 40. Accordingly, a pressure is introduced into the chamber 40.1, which acts on the piston 45 and thus activates the tensioning cylinder 40. Accordingly, the piston 45 moves the piston rod 41 (chamber 40.2 must be de-pressurized to do so). Simultaneously, the fluid port 100.2 is used to connect the first pump chamber 102 to the chamber 80.2 of the actuator 80. This pump pressure causes a displacement of the piston 82 in the actuator 80. This adjustment results in the coupling 81 being entrained from the right to the left. To prevent the actuator 80 from blocking, the chamber 80.1 on the other side of the piston 82 is de-pressurized into the pipe leading away from the accumulator 150. The hydraulic oil is thus de-pressurized into this accumulator pipe and fills the accumulator 150 until the pressure exceeds the pressure set in valve 187. Particularly preferably, the accumulator pressure at maximum filling quantity and the set pressure value of valve 187 are balanced. At the same time, the oil returning via the check valve 193 refills the front chamber 80.2, which gains volume during the pumping process. For this purpose, the actuator 80 has to have a certain area ratio or the return oil quantity of the tensioning cylinder 40 is used for this purpose. If this process causes the pressure in the pipe to rise above a preset limit, the pressure is discharged into the tank 160 via the relief valve 187.
As mentioned above, the first pump stroke may be followed by a second or more pump strokes. Two unidirectional valves 184, 185 are used to secure the pressure in the tensioning cylinder 40 and in the actuator 80 after the first pump stroke (see
If the pressure rises above the value set in the valve 186, the discharged oil fills the accumulator 150. If the pressure rises above the value set in the valve 190, the oil is transferred from the chamber 103 to 104. In doing so, the oil remains in the system and is always ready for use in the next pump stroke, even after long periods at pressure limitation.
When the overload has ended, i.e. the crushing gap 24 has been opened and the uncrushable object has left the crushing chamber 23, the valves 181 and 183 are moved to their original position. In this case the actuator unit 100 is also moved back to its prepared waiting position, as shown in
Number | Date | Country | Kind |
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10 2018 110 265.8 | Apr 2018 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/059216 | 4/11/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/206654 | 10/13/2019 | WO | A |
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Number | Date | Country | |
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20210138477 A1 | May 2021 | US |